Poster

P8: Totally laparoscopic versus open gastrectomy for gastric cancer in a Hong Kong major regional centre: A matched case-control study

BYO Chan, KKW Yau and CKO Chan

Department of Surgery, Queen Elizabeth Hospital, 30 Gascoigne Road, Kowloon

Department of Management Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong

Aim: Laparoscopic gastrectomy revolutionized the management of gastric cancer. Yet no local data concerning the efficacy and safety of such procedures exist. This study aims to compare outcomes following laparoscopic versus open gastrectomy for gastric cancer at a major regional centre in Hong Kong.

Methods: Forty-three patients who had laparoscopic gastrectomy performed from January 2009 to December 2014 were compared with 185 patients undergoing open gastrectomy during the same six-year period. Cases and controls were matched for age, sex, American Society of Anaesthesiologists (ASA) class, presence of neoadjuvant therapy, tumour location, type of operation done and pathological stage. Endpoints were perioperative and long term outcomes including survival and recurrence.

Results: Thirty six patients (16%) has early gastric cancer, the rest 192 (84%) having advanced disease. Distal gastrectomy and total gastrectomy each accounted for 105 out of 228 procedures (46%). No difference was demonstrated in radicality, length of operation, overall complications, operative or 30-Day mortality, margin clearance, survival time and disease recurrence. Laparoscopic approach was associated with shorter post-operative length of stay (10 vs 11 days, p = 0.02), higher lymph node yield (31 vs 24, p = 0.048) and higher rates of adjuvant therapy (OR 5.70, p=0.001). In subgroup analysis, less minor complications (OR 0.264, p=0.003) was seen in the laparoscopic group.

Conclusion: Laparoscopic gastrectomy has matured in our unit offering a safe and effective treatment modality, even potentially superior in terms of oncological outcomes compared to traditional open surgery for both early and advanced, surgically resectable gastric cancer patients.

P9: Accuracy of CT virtual colonoscopy of detecting colonic lesion in endoscopic obstructive left side colorectal cancer

C Chan

From surgery, PYNEH

Background: There are 10% patient have synchronous colorectal cancer. In the group of endoscopic obstructive left side colorectal cancer, there is completion colonoscopy 3 months after colectomy to screen synchronous tumor in our center.

CT virtual colonoscopy before operation can provide more information on significant colonic lesion which may alter the operative management and the timing of completion colonoscopy.

The aim of this study is to compare the accuracy of CT virtual colonoscopy.

Method: This is retrospective study includes 45 patients who had endoscopic obstructive left side colorectal cancer from 4/2015 to 7/2016. These 45 patients had CT virtual colonoscopy before operation and complete colonoscopy 3 months after operation. The colonic lesion detected in CT virtual colonoscopy and completion colonoscopy was compared. The colonic lesion is classified into significant lesion (>= 1 cm) and non-significant lesion (<1 cm).

Results: The total sensitivity of CT virtual colonoscopy is 33.3%. For significant colonic lesion (>=1 cm) and non-significant colonic lesion (<1 cm), the sensitivity are 50% and 21.4% respectively. The specificity of CT virtual colonoscopy is 85.7%

Conclusion: The sensitivity of CT virtual colonoscopy is not high enough to detect significant colonic lesion and cannot replace the important role of early completion colonoscopy. Early post-operative colonoscopy in endoscopic obstructive left side colorectal cancer is recommended. The technique of CT virtual colonoscopy should be investigated to improve the accuracy.

P10: Bowel obstruction due to obturator hernia - A retrospective cohort study comparing the outcomes between two consecutive decades

BHH Cheung, J Yip, DCC Foo, O Lo and WL Law

Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, China

Aim: The prevalence of obturator hernia increases with the ageing population. This study aims to review the surgical outcome of emergency repair for patients with obstructing obturator hernia.

Methods: All cases presented with obturator hernia since 1998 were included. Patients’ characteristics, operative findings, and postoperative outcomes were retrospectively reviewed and analyzed between two consecutive decades (1998-2007 vs 2008-2017) with SPSS version 20.

Results: All were Chinese females with a median age of 88 (range 77 - 100). Though the patients had more advanced median age (89.5 vs 87) in the second decade, comorbidities were similar between these two periods. In total 41 patients underwent 45 operations and 28/46 (62.2%) were performed in the second decade. The most common postoperative complication was pneumonia (29.4% from 1998-2007 vs 39.3% from 2008-2017 respectively). However, less intensive care unit admissions (17.6% vs 14.3%) and tracheal intubation (17.6% vs 3.6%) were noted in the second decade. Probably this may be associated with frequent bronchoscopic toileting (11.8% vs 21.4%) and more non-invasive ventilatory support (5.9% vs 14.3%) in this period. No significant differences were noted in overall complication rate (64.7% vs 64.3%, p=1.00) and 30-day mortality (17.9% vs 17.6%, p=1.00).

Conclusions: Advanced age was noticed in our patients presenting with obstructing obturator hernia. Despite high incidence of postoperative pneumonia in these elderly, with frequent bronchoscopic toilet and non-invasive ventilator support, the overall complication rate and mortality were comparable in these two consecutive decades.

P11: Laparoscopic versus open ventral incisional hernia repair with mesh: A retrospective cohort study in a local institute

SH Cheung, DCT Lam and TL Chow

Department of Surgery, United Christian Hospital, Hong Kong

Aims: Laparoscopic repair with synthetic mesh is gaining popularity in treating incisional hernia. We would like to review the clinical outcomes and safety between open and laparoscopic repair of ventral incisional hernia.

Methods: All patients undergoing elective incisional hernia repair with mesh, in either open or laparoscopic manner, from Jan 2012 to Dec 2016 in United Christian Hospital were included. Exclusion criteria included repair under emergency setting and repair without mesh. Patient’s baseline demographics, peri-operative parameters and post-op complications were evaluated. The primary end point was the recurrence rate. Secondary outcomes included operative time, blood loss, hospital stay and complications.

Results: A total of 97 patients were eligible for analysis: 58 (59.8%) open repair (O) VS 39 (40.2%) laparoscopic repair (L). Patient’s gender and age were comparable in both groups. Laparoscopic group had significantly larger size of defect (O = 4.3+/−3.18 cm VS L = 7.2+/−4.40 cm, P = 0.001). The mean follow-up time for both groups was similar (O = 19 weeks +/− 16.69 VS L = 13 weeks +/− 10.06, p = 0.057). 3 patients in open group and 6 patients in laparoscopic group had recurrence but it was statistically insignificant (O = 5.17% VS L = 15.39%, p = 0.152). Longer operative time was observed in laparoscopic group (O = 93+/−52.36 min VS L = 137+/−61.77 min, P < 0.001). There was no difference in the blood loss (O = 25+/−71.57 ml VS L=9+/−12.83 ml, P = 0.193) and hospital stay (O=5.2+/−6.25 days VS L = 4.2+/−3.02 days, P = 0.355). The overall major (Clavien-Dindo Class III or above) (O = 1.72% VS L = 2.56%, p = 1.00) and minor (Clavien-Dindo Class I-II) (O = 3.45% VS L = 5.13%, p = 1.00) complication rate was comparable between two groups.

Conclusion: Laparoscopic incisional hernia repair is a feasible alternative to open repair with comparable short term recurrence rate and complications. Further followed-up is required to observe for the long term safety and efficacy of laparoscopic repair.

P12: The management of gallstone ileus: Experience of a single centre in HKSAR

WY Chung, KF Wong and SK Leung

Introduction: Gallstone ileus is mechanical bowel obstruction due to impacted gallstone coming from the gall bladder through cholecystoenteric fistula. It is a rare disease, affecting more female elderly and many of them have multiple co-morbidities. Clinical picture is non-specific, and diagnosis is by imaging or intraoperative finding. The best surgical treatment is still controversial. This study aims to re-evaluate the management of gallstone ileus.

Methods: We performed a retrospective case series study of all the patients diagnosed to have gallstone ileus between 2003 and 2016 in our centre.

Results: A total of 28 patients were studied. There were 9 male (32%) and 19 female (68%) patients. The median age was 78 (from 47 to 97). The clinical presentations were non-specific. CT scan was effective in diagnosing gallstone ileus, and the use of CT scan had reduced the time for diagnosis (mean = 2.3 days vs 4.9 days, P = 0.01). 24 cases were treated with enterolithotomy alone and the recurrence rate was 8.3% (N = 2). There was no statistically significant difference in morbidity and mortality between patients receiving enterolithotomy alone and concomitant cholecystectomy during enterolithotomy. The overall postoperative 30-day morbidity was 29% and mortality was 11% (N = 3). The 3 cases of mortality were all associated with post-operative pneumonia (P<0.01).

Conclusions: CT scan is effective and accurate in diagnosing gallstone ileus. Majority of our patients were treated by enterlithotomy without cholecystecomy. Large scale studies are required to dictate the best surgical treatment for gallstone ileus.

P13: Laparoscopic Anatomical resection for recurrent Hepatocellular carcinoma at S8 using Laparoscopic Aquamantys Bipolar sealer/ Energy device combo

TP Fung, S Lam, SW Wong and D Tam

Aim: Laparoscopic resection of S8 liver tumor is a difficult procedure in terms of anatomical location and the difficulty in control bleeding. We present our laparoscopic S8 resection in a case of recurrent HCC at the previously Radiofrequency ablated zone using Aquamantys Bipolar sealer

Method: The patient was put supported up at right side at 45 degree. The first 12mm trocar was inserted at subumbilical region. Then 3 other 12 mm trocars were inserted at the epigastric, right mid-clavicular line and right anterior axillary line. After adhesiolysis, IOUS was performed to localize the lesion and marked the transection line. The right liver was not mobilized. Liver transection was effected with Harmonic scalpel. Retraction and hemostasis was achieved by the Laparoscopic bipolar sealer. After the transection at right and left side of the lesion was developed adequately, IOUS was performed again to make sure the deep margin was adequate. Liver transection was effected till reaching the segment 8 Glissonean pedicle and it was transected with Endovascular stapler.

Result: We performed pure laparoscopic S8 resection for 1 patient. The operative time was 3 hours 47 minutes. Blood lost was 100 ml. The post-operative course was uneventful. The specimen confirmed HCC with adequate margin.

Conclusion: Laparoscopic anatomical resection of S8 is a difficult procedure. The use of laparoscopic bipolar sealer can serve the purpose of retraction and hemostasis and help to clear up the surgical field to facilitate liver transection

P14: Free hand FNAC is a good alternative to USG guided FNAC of parotid gland tumor – A single centre retrospective review

DSW Hung and EYL Lai

Queen Elizabeth Hospital, Yau Ma Tei, 30 Gascoigne Road

Aim: Fine-needle aspiration cytology (FNAC) is a commonly used diagnostic tool to evaluate lesions of the parotid gland. However, ultrasound (USG) guided FNAC requires expertise, which may not be always be immediately available.

The aim of our study is to evaluate the accuracy and yield of free hand FNAC versus ultrasound guided FNAC and its subsequent correlation to the final pathology in order to evaluate its use as a pre-operative investigational tool.

Methods: A retrospective review was carried out for patients who underwent superficial, partial, or complete parotidectomy at the Queen Elizabeth Hospital by the general surgical team during 1/4/2008 to 31/3/2016. Results for 176 surgeries performed were analyzed. 155 cases with pre-operative FNAC of the parotid were included in the study.

Results: USG guided FNAC and free hand FNAC both have high sensitivity (USG guided FNAC 92.9% vs free hand FNAC 90%) and specificity (100%) for diagnosing malignancy pre-operatively. Free hand FNAC does not have a lower yield and has not been shown to be statistically inferior to USG guided FNAC.

Conclusion: Free hand FNAC should be considered an alternative in selective cases where lesions are easily identified and accessible for free hand FNAC.

P15: Endovascular thrombectomy and thrombolysis for cerebral venous sinus thrombosis

ACO Tsang, AC Hwang, GKK Leung and WM Lui

Division of Neurosurgery, Department of Surgery, The University of Hong Kong, 102 Pokfulam Road, Queen Many Hospital, The University of Hong Kong

Aim: Cerebral venous sinus thrombosis is a rare but severe cause of stroke with irreversible complications including venous infarction, intracranial hemorrhage, and extensive cerebral edema which lead to high mortality. Current intravenous anticoagulation treatment has limited efficacy in extensive thrombosis. With advancement in endovascular thrombolytic techniques in arterial occlusion, the application of thrombectomy device to improve venous sinus thrombosis is being investigated.

Methods: A retrospective review of cerebral venous sinus thrombosis patients treated from 2014 to 2017 with endovascular thrombectomy was carried out. Patients refractory to medical anticoagulation was treated with transvenous endovascular aspiration thrombectomy using large bore thrombectomy catheters, followed by placement of microcatheter for local thrombolytic infusion at the site of thrombosis. The angiographic and clinical outcome was reviewed.

Results: Four patients with acute complicated cerebral dural venous sinus thrombosis were treated by transvenous aspiration thrombectomy with 5Max ACE catheters. For residual thrombus occluding a segment of the dural venous sinus or cortical vein, a microcatheter was left in-situ locally at the occlusion site for post-procedural continuous urokinase infusion for thrombolysis.

Partial or near total recanalization was achieved with first stage aspiration thrombectomy, and all patients had re-establishing antegrade dural venous sinus flow and improved venous stasis. Continuous thrombolytic infusion was given for 2 days with reopening of critical cortical veins or further regain of the dural venous sinus lumen. There were no procedural-related complication and no progression of hemorrhage. One patient required decompressive craniectomy for diffuse cerebral edema. All patients recovered to mRS 1 at last follow up.

Conclusion: Endovascular aspiration thrombectomy followed by continuous local infusion of thrombolytic agent appeared to be a safe and efficacious treatment for cerebral dural venous sinus thrombosis refractory to medical treatment.

P16: The immune profiles of long-term survival recipients after liver transplantation

JJ Jia,^1,2,3 JJ Huang,^1,3 L Geng^1,2,3 and SS Zheng^1,2,3

¹Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, 310003,Hangzhou, China

²Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health; Department of Hepatobiliary Surgery, the First Affiliated Hospital, Zhejiang University, College of Medicine, Hangzhou, 310003 ,P. R. China

³Key Laboratory of Organ Transplantation, Zhejiang Province, Hangzhou 310003,China

This work was supported by National Natural Science Major Project of China (No.915422058); Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No.81421062); National Natural Science Foundation of China (No.81373160); China Postdoctoral Science Foundation (2017M610374).

Background: Tacrolimus (TAC) has become the cornerstone immunosuppressant used in most liver transplantation (LT) recipients. However, TAC-related toxicity has frequently occurred as a consequence of over immunosuppression in long-term survival recipients. Here we aimed to monitor the dynamic immune profiles and optimize a “tacrolimus minimizing” strategy for long-term survival recipients.

Methods: 85 patients who received LT were enrolled in our study. Blood TC and the immune profiles of LT patients at different time point were detected. Besides, long-term survival patients are grouped according to blood TC, with the relating clinical information collected for analysis.

Results: Mean blood TC gradually declined with the extension of survival time after LT. The ratios of CD3⁺ /CD4⁺ T /NKT cells decrease firstly then increase. The frequency of CD19⁺ B cells/NK cells/Treg cells/Breg cells increased gradually with survival time. Two groups were divided according to TC (2.0 ng/ml) for recipients who survival over 10 years. 22 (48.9%) cases had a TC < 2.0 ng/mL and 23 (51.1%) cases had a TC > 2.0 ng/mL. TAC related toxicity between two groups were not statistically different (P > 0.05).

Conclusions: The characteristics of peripheral immune profiles can be summarized as follows: Treg/B/Breg/ NK cells gradually increased while T/NKT cells decrease as survival time extending. “Tacrolimus minimizing” strategy with TC less than 2mg/ml may be safe and practical for long-term survival recipients.

P17: Effect on DM control after laparoscopic sleeve gastrectomy for obesity

J Lau, T Cheung and CN Tang

Pamela Youde Nethersole Eastern Hospital (PYNEH)

Objective(s): Review on the potential benefit on Diabetes mellitus (DM) control after laparoscopic sleeve gastrectomy for obesity.

Methods: A single centre, retrospective evaluation of patients who had undergone laparoscopic sleeve gastrectomy (LSG) in PYNEH during the period from January 2010 to March 2017. Information including patient demographics, body mass index (BMI), Pre- and post-operative body weight, Hba1c, diabetic medication use were collected on follow-up and evaluated.

Results: A total of 29 patients has undergone LSG during the period, among them 21 patients has a history of diabetes mellitus (DM) and their outcomes were analysed. Their age ranged from 24 to 63, with a Male:Female ratio of 8:13. The mean pre-operative BMI was 38.2, with an average body weight of 105kg. All patients achieved weight reduction early post-operatively (range 2-34kg, mean 13kg). The % estimated weight loss (EWL) at 1 year post-operative was 63%.

The mean pre-operative Hba1c was 8.0, post-operatively majority of patients (86%) were found to have a lowered Hba1c (mean 6.5). 48% of the patients were able to stop all oral hypoglycemic agents (OHA). Two cases of post-operative haemorrhage requiring laparotomy were encountered.

Conclusion: Other than serving the purpose of weight control, laparoscopic sleeve gastrectomy appears to provide metabolic benefit on achieving better DM control with improved Hba1c level and reduction in OHA use.

P18: TG13 severity grading in prediction of surgical outcome for acute cholecystitis

ST Lau, CCN Chong, HT Lok, AKY Fung, KW Fong, YS Cheung, J Wong, KF Lee and PBS Lai

Department of Surgery, Prince of Wales Hospital, 30-32 Ngan Shing Street, Shatin, New Territories

Aim: To evaluate the clinical value of Tokyo guideline 2013 (TG13) severity grading in predicting the complication of cholecystectomy in patient with acute cholecystitis.

Method: 70 cases of acute cholecystitis with cholecystectomy performed between Jan 2015 – Dec 2015 in the Prince of Wales hospital were reviewed. Demographic factors, radiological features, TG13 severity grading, intra-operative severe bleeding or gallbladder perforation and post-operative complication were analyzed.

Result: Among 70 cases, 35(50%) are grade I, 31 (44.3%) are Grade II and 4 (5.7%) are Grade III. 42 patient undergo laparoscopic cholecystectomy, 24 patients had laparoscopic converted open surgery and 4 had open approach cholecystectomy. 5 cases had intraoperative severe bleeding, 4 cases had intraoperative gallbladder perforation and 12 cases had post-operative complication (including wound infection, chest infection, ileus, intra-abdominal collection and haematoma). No mortality was recorded. TG13 grade III have higher chance of intraoperative gallbladder perforation (p=0.04) and postoperative complication (p=0.03). TG13 severity grading is also associated with open surgery (p=0.09) and longer length of stay (p=0.00). No correlation is found between radiological features, operative approach and complication.

Conclusion: Tokyo guideline for acute cholecystitis can provide a guidance to management of acute cholecystitis. TG13 severity grading is useful in predicting surgical outcome.

P19: Predictive factors of prolonged hospital stay after esophageal and gastric resection: A regional hospital perspective

ST Lau, YF Cheung, HT Leong and WH Kwong

Department Of Surgery, North District Hospital, 9 Po Kin Road, Sheung Shui, NT, Hong Kong

Aim: To identify predictive factors associated with unnecessary prolonged hospital stay after esophageal and gastric resections so as to facilitate setting up multidisciplinary protocol to reduce total hospital stay and to enhance early recovery.

Method: 96 cases of esophagectomy and gastrectomy cases between July 2013 – Sept 2016 at a regional secondary hospital were reviewed by two clinicians. Two in-hospital mortalities were excluded. Demographic factors, premorbid status, disease nature, preoperative social support, intraoperative detail, postoperative progress, complication and total length of stay were analyzed

Results: 80 cases of gastrectomy and 14 cases of esophagectomy are included. Median of stay were 9 days and 17 days respectively. 27 cases(33%) and 4 cases(28%) had prolonged hospital stay for more than one day respectively. In multivariate analysis, factors including planned open surgeries (p=0.001), Planned open surgeries and conversion to open surgeries (p=0.004), longer ICU stay (p=0.002), presence of complication (p=0.042) and postoperative renal impairment (p=0.023) were significant in leading to prolonged hospital stay. In univariate analysis, preoperative physiotherapy was also significant in reducing length of stay

Conclusion: Open surgeries, postoperative complications, long ICU stay and postoperative renal impairments predicts prolonged hospital stay after esophageal and gastric resection. Prolonged hospital stay potentially leads to unnecessary complication and increase in cost. Perioperative protocol can be set up aiming at these predictive factors to reduce hospital stay, complications and costs.

P20: Role of elective neck dissection in squamous cell carcinoma of maxilla. Any controversies?

CC Lee, YH Ng and YW Chan

The Univerysity Of Hong Kong, Queen Mary Hospital And Kwong Wah Hospital

Aim: Performing neck dissection in maxillary squamous cell carcinoma remains controversial. In this retrospective cohort study, we investigate the relationship between maxillary squamous cell carcinoma and neck nodal metastasis, and the role of neck dissection.

Methods: Patients with maxillary squamous cell carcinoma were identified from Queen Mary Hospital and Kwong Wah Hospital between September 2007 and December 2016 through electronic database. The medical record was reviewed. The patient demographics and tumor characteristic were analyzed by multivariate Cox regression analysis. The Cox proportional hazards model was used to assess prognostic values.

Results: A total of 50 Chinese subjects were included. The distribution of the tumor sites were: upper alveolus (N=22, 44%); maxillary sinus (N=20, 40%); and hard and/or soft palate (N=6, 12%). Pathological stages I, II, III and IV were 6%, 20%, 12% and 62% respectively. 25 subjects (50%) received elective neck dissection. Overall 14 subjects (28%) developed nodal recurrence at average of 5 months (range 1-14) after initial operation. Those who had undergone elective neck dissection was associated with lower nodal recurrence rate (6% VS 22%, p=0.012) and better disease-specific survival (12% VS 28%, p=0.021). The hazard ratio to develop nodal recurrence was 4.035 (95%CI 1.13-14.48, p=0.032) for not receiving neck dissection. The hazard ratio to disease-specific survival was 3.240 (95%CI 1.32-7.94, p= 0.010) for nodal recurrence.

Conclusions: We have demonstrated better neck disease control and disease-specific survival in maxillary squamous cell carcinoma patients. Due to the small sample size, further studies are necessary to determine the appropriate type of neck dissection.

P21: Learning curve in colorectal endoscopic submucosal dissection following hospital authority credentialing guidelines

KY Lee and CM Poon

Department of Surgery, Tuen Mun Hospital, 23 Tsing Chung Koon Road, Tuen Mun, N.T., Hong Kong

Aim: The Hospital Authority’s “Guidelines on Endoscopic Diagnosis and Management of Early GI cancers and Guidelines on Handling and Pathological Examination of Endoscopic Submucosal Dissection(ESD) Specimens for GI Neoplastic Lesion” provides clear guidelines on the endoscopists’ credentialing process to perform ESD. This study aimed to report the learning curve in colorectal ESD of a single endoscopist following this guideline.

Method: The endoscopist, a fellow in General Surgery with competency in diagnostic and therapeutic colonoscopy, attended local and overseas training workshops and had hands-on ESD training on animal models. The endoscopist then had 4-weeks observation in a dedicated center in Osaka, Japan.

Following the observation, the endoscopist started performing colorectal ESD under supervision +/- assistance. At least 10 cases of successful and non-complicated(without perforation) ESD were performed before the endosocpist became independent.

Results: The endoscopist performed 54 colorectal ESD from Aug 2015 to Apr 2017.

In total, 21 ESD were performed to accumulate 10 successful non-complicated ESD (7 cases of perforation and 7 requiring the assistance from supervisor). The results of these first 21 cases were compared to the subsequent 21 cases to determine the learning curve.

The average polyp size was 7.7cm² and 8.1cm² respectively. The average speed was 56.1min/ cm² compared to 27.9min/ cm². The rate of independence was 67%(14) compared to 86%(18) and the rate of perforation was 33%(7) compared to 10%(2).

Conclusion: Following the HA credentialing guidelines, endoscopists can receive structured training in ESD, resulting in effective learning and safe application of skills, as reflected by the significant increase in speed and rate of independence, as well as significantly smaller perforation risk.

P22: Hypoparathyroidism after thyroid surgery in the era of empirical calcium supplements

X Lo, LY Leung, TK Tam and HT Leong

Department of Surgery, North District Hospital

Aim: To identify factors associated with transient and permanent hypoparathyroidism after thyroid surgery especially with respect to empirical use of calcium and vitamin D supplements since 2012.

Methods: Total thyroidectomy and completion thyroid surgery, excluding those with concomitant parathyroid surgery, between Jan 2010 to Dec 2013 in our unit were included. Demographics, OT details, parathyroid hormone levels and need of calcium supplements were retrieved from prospectively managed database.

Results: A total of 298 patients with 263 total and 35 completion thyroidectomies were operated on during the study period. 32.6% of these patients had a cancer diagnosis with 18.5% had concomitant central compartment lymph node dissection (CCD) and 3% had lateral neck lymph node dissection. 16 patients (5.4%) had elective readmission for management of symptomatic hypocalcemia. 82.2% of patients were found to be possible for discharge on day one based on calcium level or absence of hypocalcemia symptoms with use of empirical calcium and vitamin D supplement postoperatively (p=.033), size of specimen (p=.000) and CCD being performed (p=.002) being statistically significant independent factors.Permanent hypoparathyroidism rate was 9.7% and only CCD being performed (p=.013) was an independent risk factor. Only 44.4% of patients with CCD done are symptom free on first postoperative day and permanent hypoparathyroidism affected 26.7% of these patients.

Conclusion: Empirical calcium and vitamin D supplements after thyroid surgery effectively reduce symptomatic transient hypocalcemia. CCD is an independent predictor of both transient and permanent hypoparathyroidism, its indication needs to be justified with patients well informed before embarking on it.

P23: A 5-year retrospective cohort study to compare outcome of open surgical cut down vs Ultra-sound guided percutaneous insertion of long term tunneled central venous access

YK Leung, MWY Leung, NSY Chao, PMY Tang, KLY Chung, CSW Liu, JWS Hung, YCL Leung, FSD Yam and KKW Liu

Division of Paediatric Surgery, Department of Surgery, Queen Elizabeth Hospital & United Christian Hospital, Hong Kong.

Aim of the Study: Open surgical cut-down(OSCD) is a standard approach for long-term tunneled central venous access. Ultra-sound guided percutaneous insertion(USPI) gains popularity as a minimal invasive approach. It is our aim to compare the operating time and complications of OSCD and USPI to internal jugular vein in paediatric population.

Methods: Hospital records of patients aged 3 months to 16 years underwent long-term tunneled central line insertion to internal jugular vein in a paediatric surgery centre from 2011-2015 were reviewed. Chi-square test and Student’s t-test were used for statistical analysis.

Results: Eighty-five cases were recruited with 51 OSCD and 34 USPI. Mean age for OSCD was 65.4 months and USPI was 85.8 months. 73 cases were indicated for chemotherapy, 8 cases were for total-parenteral nutrition and 4 cases were for other venous access. Early complications are defined as incidents occurred within 7 days of insertion. The mean operating time for OSCD is 57.0 minutes and for USPI is 52.0 minutes (p=0.110). Early complications included arterial puncture (p=0.155), primary displacement (p=0.653), primary blockage (p=0.640), early exist site infection (p=0.360) and early bacteremia (p=0.602) are all statistically insignificant in both group. Late complication included late displacement (p=0.310), late blockage (p=0.314), late exit site infection (p=0.208), catheter related blood-stream infection (p=0.062) and leakage or fracture of catheter (p=0.398) also showed no difference in both groups. Both techniques experienced no local bleeding or perioperative mortalities.

Conclusion: Ultra-sound guided percutaneous approach is a feasible and safe method for long-term tunneled central venous access comparing with open surgical cut-down.

P24: Treatment of cutaneous angiosarcoma of the scalp and face in Chinese - A local experience of a regional hospital in Hong Kong

JJM Lim, HY Chiu, TL Chow, WWY Kwan and CK Kwan

United Christian Hospital, 130 Hip Wo Street, Kwun Tong, Kowloon, Hong Kong

Aim: Angiosarcoma is a rare aggressive sarcoma mostly occurring in the head and neck skin in the elderly. Most existing studies originate from the Caucasians. We undertook this survey to study its disease characteristics in the Chinese.

Methods: Patients with histopathologically-verified cutaneous angiosarcoma of the head and neck in the past two decades were retrieved from our cancer registry. Demographic, clinicopathological information, treatment modalities and outcomes were recounted.

Results: A total of 17 Chinese patients were enrolled. Their median age was 81 years-old. The tumours resided in scalp alone(N=11), face alone(N=4) or both scalp and face(N=2). Two patients were found to have distant metastases. The dispositions were surgery(N=6), surgery with adjuvant radiotherapy(N=1), palliative radiotherapy(N=5) and palliative chemotherapy(N=3). Two patients refused treatment initially. Of the 7 patients treated surgically, there were 4 local and 2 regional recurrences. The median time for relapse was 7.5 months. Sixteen patients have died; the causes of death were disease-related in 12. Four other patients died of inter-current illnesses. One patient was surviving with the disease. The median overall survival was 11.1 months. The longest survival in our series was 42 months.

Conclusion: The outcome of angiosarcoma is poor. High index of suspicion is mandatory for prompt diagnosis. Adjuvant radiotherapy is recommended following surgery. The benefits and roles of systemic treatment with surgery or radiotherapy require validation with further studies.

P25: Prospective study for unilateral cleft lip repair using modified Fisher’s technique

CSW Liu, *WS Hung, *LY Chung, *SD Yam, CL Leung, *MY Tang, *WY Leung, SY Chao, ^CH Ho, ^WK Wong, ^SC Fung and KKW Liu

Division of Pediatric Surgery, Department of Surgery, United Christian Hospital

*Division of Pediatric Surgery, Department of Surgery, Queen Elizabeth Hospital

^Department of Dental Maxillofacial Surgery, United Christian Hospital

Aim: Fisher’s technique (anatomical subunit approximation) for unilateral cleft lip repair has the advantages of minimizing the size of the triangular flap due to Rose-Thompson effect, yet placing the scar on the ideal philtral column. We have few modifications from the original Fisher’s technique. We review our experience for unilateral cleft lip patients using modified Fisher technique.

Methods: From May, 2017 onwards, 5 consecutive unilateral cleft lip patients were repaired by modified Fisher technique with overlapping of orbicularis muscle plus overcorrection of nostril width and height. Objective assessment of the nasolabial outcome was done using Asher-McDade aesthetic score via evaluating standardized two-dimensional clinical photos comparing validated reference photos by three independent maxillofacial surgeons. A patient-centered outcome assessment was performed using satisfaction with appearance scale (SWA) questionnaire by parents.

Results: 5 consecutive patients with unilateral cleft lip were recruited. 4 were incomplete cleft lip and 1 had complete cleft lip. Mean age of operation was 3 months. Mean follow up period was 1.5 months. The average size of triangular flap used is small 1.7 mm (range 1 – 2mm). None of these patients had complications. Median Asher-McDade score for nasal form, nasal symmetry, vermilion border and nasolabial profile were 1.15, 1, 1.8 and 1.15 respectively (1 = excellent, 5 = poor). Parents were satisfied with the aesthetic outcome with median overall satisfaction score of 8.5 (out of 10).

Conclusions: Modified Fisher’s technique is applicable to all extent of unilateral cleft lip patients. Satisfactory short term aesthetic and patient centered outcomes were achieved.

P26: Robot-assisted laparoscopic adrenalectomy - A retrospective review in a single centre

GYL Liu, SCY Law, CY Choi and CN Tang

Department of Surgery, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong SAR

Aim: Laparoscopic adrenalectomy is an established approach for adrenal pathologies, as it reduces access trauma and improves vision. Over the past 10 years, robot-assisted approach has been increasing practiced for the management of more challenging adrenal masses. We aim to review of the experience of robot-assisted adrenalectomy in a single surgical centre in Hong Kong.

Methods: Patients who underwent robot-assisted adrenalectomy in a single surgical centre were reviewed retrospectively during the period from August 2011 to May 2017. Their demographics and postoperative outcomes were analysed.

Results: Among the 49 patients undergoing robot-assisted adrenalectomy, 25 were male and 24 were female. Their mean age was 54 years. The majority of patients (n=36, 73%) had functional adrenal cortical tumour, other indications included local symptoms due to large size of lesion, indeterminate nature of lesion, and isolated adrenal metastasis. Majority lesions were on the left side (61%). Two patients had concomitant pathology necessitating other procedures performed in the same session. The mean size of adrenal pathology is 29mm, with the largest adrenal lesion excised measured 100mm. Mean operation time was 123.6 minutes. Shortening in operation time was observed as experience accumulated. Blood loss was minimal. Postoperative complication occurred in 1 (2%) patient with colonic injury. The mean hospital stay was 2.9 days (range, 1-16 days). No disease recurrence was noted at the latest follow up.

Conclusion: Robot-assisted adrenalectomy is feasible and safe in experienced hands. It may potentially shorten the operation time.

P27: Short term outcomes of laparoscopic sleeve gastrectomy performed in a newly established bariatric surgery team in a local hospital in Hong Kong

EYJ Lo, TM Tsui, YS Sze and TT Tang

Yan Chai Hospital, 7-11 Yan Chai Street, Tsuen Wan, New Territories, Hong Kong

Background: Laparoscopic sleeve gastrectomy (LSG) has been gaining popularity as a choice of bariatric surgery due to its lower morbidity and safer complication profile. Some studies have shown promising results in terms of BMI reduction and diabetic control. In Hong Kong bariatric surgery is still in development, and most of local data was obtained from tertiary centres.

Aim: This study aims to evaluate and compare the short term BMI and metabolic outcomes in morbidly obese Chinese patients received LSG with those received standard medical care and lifestyle modification advice from dietitian and physiotherapist alone in a community hospital in Hong Kong.

Method: We conducted a retrospective cohort study on patients receiving LSG in Yan Chai Hospital since the starting of its surgical bariatric service till December 2016. Patients who attended the metabolic and bariatric surgery clinic but did not receive LSG are screened, and those with similar baseline characteristic are selected for comparison. BMI and metabolic outcomes, including HbA1c value, diabetic and anti-hypertensive medications requirement, lipid profile, are compared at entry and 6 months after treatment. Complications of surgery are also evaluated.

Results: From January 2016 to December 2016, 17 patients aged 46.1 ± 8.8 with BMI 39.7 ± 4.09 kg/m² received LSG in Yan Chai Hospital. Patient with LSG have statistically significant reduction in BMI (8.2 ± 0.64 vs 0.46 ± 1.36, p= 0.00), HbA1c change (-1.17 ± 1.55 vs 0.024 ± 0.75, p=0.01), diabetic (-0.74 ± 0.85 vs 0.06 ± 0.24, p=0.01) and anti-hypertensive ( -0.82 ± 1.01 vs 0.00 ± 0, p= 0.02) medications requirement, triglyceride reduction (-0.93 ± 0.9 vs -0.02 ± 0.46, p= 0.001) and improvement in HDL level (1.11 ± 0.19 vs 1.05 ± 0.17, p=0.016). Only one patient suffered from urinary tract infection, and there was no other complication.

Conclusion: LSG appears to be a safe and effective surgical option in management of obesity, and satisfactory results may be replicable in other peripheral hospitals.

P28: 10 Years experience of outpatient hemithyroidectomy – What do we learn?

X Lo, TK Tam and HT Leong

Department of Surgery, North District Hospital and Alice Ho Miu Ling Nethersole Hospital

Aim: Outpatient thyroidectomy had been debated over the years with concerns of its safety especially with regard to postoperative haematoma. We wish to assess safety and factors that may affect outcome in this group of patients.

Methods: Retrospective analysis of patients who underwent hemithyroidectomy under general anaesthesia since our unit started outpatient service.

Results: A total of 531 patients underwent hemithyroidectomy from Aug 2005 to Oct 2016. 52 patients were planned for overnight stay and excluded from analysis. 59 patients (12.3%) required overnight stay. Only 5 patients (1.0%) developed a haematoma and all were discovered before planned discharge time and operated on with extra stay. There was no 30-day mortality. 11 patients (2.3%) were readmitted through emergency within 30 days and none were related to hematoma. Recurrent laryngeal nerve injury occurred in 8 patients with 5 of them subsequently recovered. On univariate analysis, patients’ thyroid status being not euthyroid was the only significant factor associated with haematoma (p=0.030). Longer OT time (p=0.002), post-operative haematoma (p=0.002) and larger preoperative nodule size (p=0.022) were significantly associated with overnight stay on multivariate analysis. Patient’s age, thyroid status and intraoperative blood loss were statistically significant on univariate analysis only.

Conclusion: Outpatient thyroidectomy is safe in a highly selected group of patients despite some may still need inpatient care. Day surgery units with access to inpatient facilities without long distance transfer are in a better position to provide such care. Availability of expert surgical and anaesthetic teams to shorten operative time and minimise complications is especially important.

P29: Surgical treatment of infective endocarditis: A 3-year retrospective review

TW Lum, HM Chan, WS Ng, HY Chan, SH Chu, WK Ng, CC Ma and HL Cheung

Department of Cardiothoracic Surgery, Queen Elizabeth Hospital, Hong Kong

Aim: To review the demographics, etiology and surgical treatment of infective endocarditis in the Department of Cardiothoracic Surgery in Queen Elizabeth Hospital

Methods: Patients underwent surgical treatment for infective endocarditis during June 2014 to June 2017 was included in the present study. The clinical data were retrieved via the electronic patient record system.

Results: There were 41 patients (24 Male, 17 Female), with mean age 51 (range 19 - 84) underwent surgical treatment for infective endocarditis in the study period. All patients underwent valvular surgery. There were 29 single valve procedures [AVR (39.0%) , MVR (24.4%), TVR (2.4%), PVR (2.4%) , MVA (2.4%) ]; There were 10 double valve procedures [ AVR + MVR (9.8%), MVR + TVR (2.4%), MVR + TVA (4.9%), AVR + MVA (7.3%) ] and 1 triple valve procedure MVR+AVR+TVA (2.4%). Concomitant CABG was required in one patient requiring single valve procedure.

The commonest causative organism was Viridans Streptococci (24.4%). Nine patients (22.0%) were culture negative. There were 4 cases (9.8%) of prosthetic valve endocarditis.

There were 3 patients requiring delay sternum closure and one patient requiring re-sternotomy for hemostasis in early post-operative period.

The overall 30-day mortality was 2.4%.

Conclusion: Surgical treatment of infective endocarditis continues to be challenging and the clinical outcome remains satisfactory.

P30: Foreign body aspiration in pediatric patient managed with emergency rigid bronchoscopy: A 3-year review

TW Lum, HM Chan, WS Chau, CC Ma and HL Cheung

Department of Cardiothoracic Surgery, Queen Elizabeth Hospital, Hong Kong

Aim: To review pediatric patient presented with foreign body aspiration requiring emergency rigid bronchoscopy in Queen Elizabeth Hospital.

Method: All pediatric patients presented with aspiration of foreign body managed with emergency rigid bronchoscopy in the Department of Cardiothoracic Surgery during June 2014 to June 2017 were included. The clinical data were retrieved via the electronic patient record system.

Results: A total of 6 patients (Male=3, Female=3) with mean age of 5 (range 10 months to 18 years old) has been included in the present study. The commonest presentations were cough (50%) and wheeze (50%). All patients had pre-operative CXR and only one patient had pre-operative CT scan. The commonest aspirated foreign body was peanut (50%) and all foreign were identified from the right side airway. The mean operation time was 28 minutes (range 9 to 62 minutes) and the mean length of hospital stays was 3.2 days (range 2 to 4 days).

Conclusion: All pediatric patients suspected to have foreign body aspiration with symptoms should have early intervention in order to prevent airway obstruction or inflammation. History taking from parents or carers dictated the timing and indication requiring for surgical management.

P31: Effects of SFPR4 on insulin secretion and blood glucose regulation of insulinoma and its mechanism

L Ma, L You, L Cong, YP Zhao*

Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences/Peking Union Medical College, No.1 Shuaifuyuan Wangfujing, Dongcheng district, Beijing, China

Aim: To investigate the expression and activation of SFRP4 and Wnt/β-catenin pathway in human insulinoma and serum, and to clarify their relativity with clinical and pathological parameters. To observe how SFRP4 affects the proliferation of insulinoma cells and the secretion of insulin. To evaluate the impact of SFRP4 on blood glucose regulation and the associated mechanism.

Methods: SFRP4 and β-catenin expressions in tissues and serum were examined by IHC and ELISA. The clinical parameters were analyzed by statistical methods. CCK8 method and GSIS test were used to determine SFRP4’s impact on the proliferation and secretion of insulinoma cells. SFRP4’s impact on Wnt/β-catenin pathway, was observed by Western blotting. qRT-PCR was used to examine how SFRP4 influences glucose output of hepatocytes and the expressions of key enzymes in gluconeogenesis.

Results: The expression of SFRP4 was significantly upregulated in insulinoma. Tissue SFRP4 expression was positively correlated with the blood glucose level and serum SFRP4 level was negatively correlated with insulin level. SFRP4 led to a promoted cell growth of INS-1, and resulted in a dampened capacity of insulin secretion. SFRP4 triggered glucose output in hepatocytes, and upregulated gluconeogenesis program.

Conclusions: SFRP4, which upregulates in insulinoma, may promote the aberrant activation of Wnt/β-catenin pathway, thus, participate in the pathogenesis and development of insulinoma. SFRP4 represents its vital role in the maintenance of blood glucose levels via inhibiting the insulin secretion in insulinoma and promoting gluconeogenesis in liver.

P32: Early results of cavitron ultrasonic surgical aspirator (CUSA) assisted zero-ischemia non-clamping laparoscopic partial nephrectomy

CWH Mak, RWH Chu, WKW Chan, CL Cho and IC Law

Division of Urology, Department of Surgery, Kwong Wah Hospital

Aim: Preserving renal function is one of the most important aim in partial nephrectomy for renal tumour. Our study evaluates the efficacy and safety of zero-ischemia non-clamping partial nephrectomy with the use of Cavitron Ultrasonic Surgical Aspirator (CUSA).

Methods: A total of thirty-six patients underwent laparoscopic partial nephrectomy from August 2010 to February 2017. Among these cases, thirteen patients had CUSA assisted non-clamping laparoscopic partial nephrectomy (CUSA group) from May 2015 to February 2017. Clinical and laboratory parameters of patients in CUSA group were compared with eleven patients who had laparoscopic partial nephrectomy with main artery clamping method (MAC group).

Results: Renal mass complexity of both groups were comparable as reflected by similar RENAL-nephrometric score (CUSA: 6.9; MAC: 7.2; p=0.73). There were no major surgical complication in both groups. CUSA group had a smaller mean blood loss estimation (311ml, 368ml) but a longer average operation time (294 mins, 264 mins).

MAC group had a significant decrease in renal function on post operative day 0 (eGFR:58.7; p=0.00) and day1 (eGFR:57.4; p=0.01) when compared with pre-operative eGFR (77.0). CUSA group patients had a relatively static renal function after operation (eGFR trend: 73.6, 69.5, 65.7).

Patients in CUSA group were associated with a significant shorter hospital stay (5.5days, 8.6 days; p=0.03).

Conclusion: CUSA assisted zero-ischemia non-clamping laparoscopic partial nephrectomy is a safe technique and is associated with better early postoperative renal function and a shorter hospital stay.

P33: Sentinel lymph node biopsy with indocyanine green lymphoscintigraphy in squamous cell carcinomas of the tongue: Prospective study of 16 cases

JCW Ng and JYW Chan

Department of Surgery, Queen Mary Hospital

Aim: Selective neck dissection (SND) is currently the standard of nodal staging for occult nodal metastasis in patients with clinically N0 squamous cell carcinoma (SCC) of the tongue. This study aims to investigate the feasibility of intra-operative real time indocyanine green (ICG) mapping of sentinel lymph node (SLN) with near-infrared fluorescence.

Methods: Between January 2015 and July 2016, consecutive patients with biopsy proven tongue SCC with clinically N0 status were included. Exclusion criteria included nodal metastasis, previously treated neck and allergy to ICG. Intra-operatively, 2.5mg of ICG was injected submucosally around the tumour. Real-time mapped SLN was excised before SND (level I to III). The ability of ICG identifying SLN was examined. The number and level of the SLNs, the according signal-to-background ratio and the histopathology of the SLN and the SND specimens were studied.

Results: A total of 16 consecutive patients were recruited. Among them, 9 were male and the median age was 54 (range, 32-82) years. Fourteen patients had 22 SLN identified at a mean of 153.1 (range, 88 – 222) seconds after ICG injection. Seven patients had SLN positive for malignancy. None of the SND specimens harbored microscopic tumour deposits. One patient pN1 post radiotherapy alone developed local recurrence whereas one patient pN2b receiving radiotherapy alone succumbed with distant recurrence. Other patients remained disease free at the last follow-up.

Conclusion: Real time ICG lymphoscintigraphy is feasible and reliable for the identification of SLN for patients with clinically N0 carcinoma of the tongue. It can potentially replace routine SND for better nodal staging.

P34: Hidradenitis suppurativa: A diagnostic dilema

JCW Ng, RCL Chan and JYW Chan

Department of Surgery, Queen Mary Hospital

Aim: This is a retrospective study to evaluate the efficacy of clinical diagnosis, patient demographics and the site of involvement of hidradenitis suppurativa (HS) in oriental Chinese.

Method: Data were retrieved from the Department of Pathology tissue bank record with the key word of “hidradenitis suppurativa” from 2007 to 2016. Only patients with histopathological features of HS were included. Respective medical records were subsequently retrieved for data analysis.

Results: Over the study period, 24 patients with HS were identified. The disease was more common in male (n = 13, 54.2%), and the median age was 35.5 years old (Range, 21-73 years). Accurate clinical diagnosis during the first consultation was made only in 25% of patients. The commonest misdiagnoses were simple abscess (37.5%) and infected sebaceous cyst (25%). Majority (79.2%) of the patients were affected at the axilla, followed by buttock (16.7%), and vulva (4.2%). Among these patients, 58.3%% responded well to simple excision, while the remaining patients presented with a more aggressive course of disease, requiring multiple resection and reconstruction as well as systemic therapy using isotretinoin or antibiotics such as clarithyromycin or clindamycin, or anti-TNF group such as adalimumab, together with topicals such as urea cream.

Conclusion: Hidradenitis suppurativa often presents as a diagnostic challenge. Awareness among the clinicians and prompt referral to surgeons is important to ensure a timely and proper treatment of the condition. Multidisciplinary approach of management between surgeons and dermatologists is essential for optimal control.

P35: Endovenous ablation using venaseal sapheon closure system for treatment of great saphenous vein incompetence

WK Ng, PY Wong, SM Kwok, KF Cheung, CK Chan, TL Cheng and KM Chan

Department of Surgery, Princess Margaret Hospital, 2-10 Princess Margaret Hospital Road, Lai Chi Kok, Kowloon

Aim: To analyze the results of using VenaSeal (cyanoacrylate embolization systems) in patients with GSV incompetence.

Methods: We conducted a prospective, single arm study to evaluate the results of using VenaSeal in patients with GSV incompetence between Oct 2015 and Dec 2016. Clinical examination, duplex ultrasound and patient's satisfaction and symptoms scores were evaluated at 6 weeks, 6 months and 1 year.

Result: 20 patients with 27 limbs were recruited in total. Technical successful rate was 96%. At 6 weeks, 96% GSVs were occluded. Only 1 case showed patent GSV at 6 weeks, with subsequent duplex at 6 months showed complete occlusion. At 1 year, the GSV occlusion rate was 78%, with most recannulation occurred over distal GSVs. Only one case developed clinical recurrence requiring reintervention. Patient's satisfaction and symptoms were measured by Chronic Venous Insufficiency Questionnaire (CIVIQ score), Venous Clinical Severity Score (VCSS), Patient Satisfactory Score (PSS) and Symptoms Score. There were significant improvement over CIVIQ score at 6 weeks (Mean 49.3 vs 40.3, p=0.03), 6 months (p=0.01), VCSS at 6 weeks (Mean 5.4 vs 2.4, p<0.01), at 6 months (p<0.01), at 1 year (p<0.01), PSS at 6 weeks (Mean 5.6 vs 2.4, p<0.01), 6 months (p<0.01), 1 year (p<0.01), and symptoms score at 6 weeks (Mean 3.9 vs 1.9, p<0.01) and 6 months (p<0.01). Clinical stage by CEAP classification also showed significant reduction at 6 weeks (Mean 2.8 vs 1.9, p<0.01), 6 months (p<0.01) and 1 year (p=0.03). Only two cases developed erythema and haemotoma after operation. No major adverse effect or complication, including deep vein thrombosis were detected.

Conclusion: In patients with GSV incompetence, VenaSeal showed a high technical successful rate, occlusion rate and significant improvement in patient's satisfactory and symptoms, without any major adverse event.

P36: Challenges in managing abdominal tuberculosis: Retrospective review

DWL Ng, SWY Luk, MHY Cheung and HT Leong

Department of Surgery, North District Hospital, Hong Kong SAR, China

Background: Making the diagnosis of abdominal tuberculosis is challenging owing to the insensitivity of the culture result. This affects subsequent treatment and prognostication. At least 760 abdominal tuberculosis cases had been reported in the past 10 years in the Hong Kong. Yet, limited regional clinical data is available.

Aim: To review demographic, clinical symptoms, diagnosis and treatment outcome of patients diagnosed with abdominal tuberculosis in Hong Kong.

Method: Patients with the provisional diagnosis of abdominal tuberculosis were included in this cohort study. Retrospective review of patients’ records was conducted at single district institute in Hong Kong between July 2007 and June 2017 inclusively.

Results: Total 21 patients were eligible and included in this study. 17 of them (80.9%) had abdominal tuberculosis. Male population was affected slightly more than female (10:7). Mean age of diagnosis was 51.6 +/- 18.9 years old. 52% (n=9) of them were chronic smoker. Abdominal pain (n= 12; 70%) was the most common presenting symptom while 6 patients developed peritoneal sign. Most of the cases were diagnosed through peritoneal biopsy (n=9; 53%), both open and laparoscopic techniques. Acid fast bacilli (AFB) culture through sputum, ascitic fluid and early morning urine samples were insensitive tests. 14 out of 17 patients (82.3%) made good recovery with timely anti-tuberculosis treatment yet 2 patients died of TB-related complication.

Conclusion: Abdominal tuberculosis affects young and old populations in Hong Kong. Early biopsy should be considered. Minimal invasive diagnostic technique is feasible in selected cases. With timely anti-tuberculosis treatment, abdominal tuberculosis is readily curable with good prognosis.

P37: Laparoscopic Nissen versus Toupet fundoplication for treatment of gastro-esophageal reflux disease - A retrospective cohort study of Chinese population in a local institute

CK So, CT Lam, KW Leung, SH Lam and TL Chow

Introduction: Laparoscopic Nissen fundoplication was firstly reported in 1991 and has been adopted as the standard procedure for patients with severe reflux disease. Partial fundoplication was postulated to be associated with less dysphagia and wind-related problems alongside recent evidences showing similar efficacy. The aim of this study was to compare the surgical safety and clinical outcomes between laparoscopic Nissen and Toupet fundoplication in Chinese population.

Method: From August, 2008 to March, 2017, 54 patients who underwent laparoscopic fundoplication for reflux disease were retrospectively reviewed. Patient demographics, perioperative parameters and postoperative outcomes were evaluated. The primary end point was the recurrence. Secondary end points included postoperative dysphagia and belching.

Results: 42 patients (77.8%) underwent laparoscopic Nissen fundoplication (NF) while 12 patients (22.2%) underwent laparoscopic Toupet fundoplication (TF). Patients' sex, age, and preoperative DeMeester score were comparable between two groups. No statistical significant differences demonstrated regarding intraoperative blood loss (NF=17 ±24.4 ml vs TF=36 ±40.1 ml, p=0.153), operative time (NF=151 ±24.1 minutes vs TF=174 ±57.0 minutes, p=0.202), and total hospital stay (NF= 3.7 ±1.3 days vs TF=4.5±1.9 days, p=0.089). The follow up time for Nissen group was significantly longer (NF=220 ±157.0 weeks vs TF= 54 ±73.4 weeks, CI=101.10-231.14, p=0.000). There was no statistical significance in recurrence (NF=11.9% vs TF=0%, p=0.575), postoperative dysphagia necessitating endoscopic dilatation (NF=16.6% vs TF=8.3%, p=0.667), and belching (NF=14.3% vs TF=8.3%, p=1.000). No surgical related morbidity and mortality observed in both groups.

Conclusion: Laparoscopic Toupet fundoplication is a safe alternative procedure in treatment of reflux disease with similar short-term efficacy and adverse effect profile when compared to laparoscopic Nissen fundoplication.

P38: Myth and controversy in cleft surgery for Pierre-Robin sequence: Are the pre-operative anthropometric measurements of their cleft palate different from those in isolated cleft palate?

PMY Tang, CSW Liu, NSY Chao and KKW Liu

Department of Surgery, Division of Paediatric Surgery, the United Christian Hospital & Queen Elizabeth Hospital/ KEC Cleft Lip & Palate Services

Aim: Cleft palates in children with Pierre-Robin Sequence (PRS) are often said to have ‘U-shaped’ configurations and therefore anatomically different from those in children with isolated cleft palate (IsCP). This study aims to distinguish if the pre-operative anthropometry of cleft palate in PRS is significantly different from that in IsCP that might predict poorer surgical outcomes.

Methods: We reviewed the clinical records of patients with PRS who underwent palatoplasty in our center from 1995 to 2015. A control group of patients with non-syndromic IsCP undergoing palatoplasty by the same surgical technique during that period of time were identified. Demographic data and palatal anthropometry before palatoplasty were analyzed with unpaired t-tests.

Results: Measurements were obtained in 16 PRS and 16 IsCP patients: respective mean palatal gap lengths were 22.1mm vs 22.0mm (p=0.764), mean gaps at uvula were 13.8mm vs 12.8mm (p=0.615), mean gaps at mid-palate were 11.1mm vs 10.9mm (p=0.915), mean velopharyngeal portal depths were 13.5mm vs 14.4mm (p=0.327), mean body-weights were 8.6kg vs 8.7kg (43^rd vs 55^th percentile, p=0.512), age at operation were 18.3months vs 12.9months (p<0.001). No fistulae complications or overt hypernasal speech were observed during postoperative follow-up in each cohort.

Conclusions: At the time of palatoplasty, patients with PRS were significantly older than those with IsCP while body-weights and weight-percentiles were similar. There was no significant difference in anthropometry of their palatal cleft in terms of gap length, widths and velopharyngeal portal depth, correlating with comparable surgical outcomes.

P39: Laparoscopic sleeve gastrectomy for weight reduction and diabetes control at a local hospital: Short term outcome measurement

RTT Tang, TM Tsui, YS Sze and KW Lui

Yan Chai Hospital

Background: Laparoscopic sleeve gastrectomy (LSG) is the most commonly performed procedure for weight reduction and diabetes control worldwide. There have been reports that the procedure is effective in weight and diabetes control in the local Chinese population in Hong Kong. This study determines if similar results are yielded at our newly established multi-disciplinary metabolic and bariatric surgery team.

Methods: This is a prospective observational studies of obese patients undergone LSG as a stand-alone procedure.

Results: In the year 2016, there were 17 patients aged 46.1+-8.8 years old. Their body mass index was 39.7+-4.09kg/m2. They were followed up at 3 and 6 months interval, and their excess body weight and HbA1C were measured.

At 3-month interval, their mean excess weight loss by percentage was 28.8%+-9.1% (n=17). At 6-month interval, their mean excess weight loss by percentage was 36.4%+-12.1% (n=15). Failed weight loss (%EWL<30%) were 55.6% (n=17) and 33.3% (n=15) at 3 and 6-month interval respectively.

9 subjects were diagnosed with DM, and were on medications. Proportions of subjects with satisfactory glycemic control (HbA1C<=7%) was 22.2%, 88.9% and 100% at 0, 3, 6 interval from surgery respectively.

Conclusions: LSG is a promising procedure for weight reduction and diabetes control, with results appreciable as early as 3 months from the procedure. Long-term data will be further collected to determine its sustained effect.

P40: Endovascular salvage for iatrogenic arterial injury from image-guided procedures

YP Tsang, JCY Lam, SYC Pang and CN Tang

Department of Surgery, Pamela Youde Nethersole Eastern Hospital, Hong Kong

Background: Iatrogenic injury has become an important cause of arterial trauma. The increasing number of percutaneous procedures could be one postulated reason. Image-guided procedure, most commonly by ultrasound, aims to increase the success rate but complications might still arise especially in difficult situations.

Method: We report two cases of iatrogenic arterial injury in our institution to illustrate the importance of endovascular salvage.

Result: The first case is an injury during double lumen venous catheter insertion for a 34-year-old patient. Arterial injury was noticed during the insertion of the Fr10 dilator but the dilator was withdrawn immediately. CT scan revealed contrast extravasation at the junction of right subclavian artery and internal mammary artery. Endovascular coil embolization of right internal mammary artery and a covered stent placement at subclavian artery were performed via right brachial approach. Completion angiogram shows good radiological result and patient was stabilized.

Another injury happened during ultrasound-guided pleural tapping in a 94-year-old lady. Arterial spurting is observed during the insertion of the Fr6 dilator. A pigtail catheter was introduced and spigotted. CT scan revealed the injury at the distal descending thoracic aorta. A 32x70mm Endurant II^TM stent-graft was introduced and deployed at the site of injury whereas the pigtail catheter was removed simultaneously. No leakage was detected on completion angiography and patient was stabilized.

Conclusion: Iatrogenic arterial injury sporadically occurs even extra-precaution is made. Prompt management with endovascular salvage might save the patients from this major complication with lower morbidity.

P41: Curative resection for left colonic carcinoma: Laparoscopic segmental resection versus formal left hemicolectomy – A retrospective analysis

KLM Tung and CW Lau

Department of Surgery, Pamela Youde Nethersole Eastern Hospital

Aim: To review post-operative outcomes between these two surgical approaches.

Method: Between Jan 2012 to Jan 2016, 78 consecutive patients with left colonic carcinoma located between distal transverse colon to recto-sigmoid junction underwent either segmental resection (SR) or formal left hemicolectomy (LH). Short term and long term outcomes were compared between the two groups.

Results: Within 5 years, 36 patients underwent segmental resection and 42 patients underwent formal left hemicolectomy. Operation time was longer in LH group while intra-operative blood loss was more in SR group. For the choice of anastomosis, in the SR group, surgeon either performed hand-sew or staple anastomosis while in LH group, all were done with staple anastomosis. The tumor staging was comparable between two groups. There were no single case of resection margin involvement and the LN harvested in the LH group were higher (13.3 in SR, 17 in LH). For post-operative outcomes, SR had a significantly higher leakage rates as compared to LH (16.7% vs 2.4%), length of hospital and postoperative complications were also higher in the SR group. Recurrence rate was comparable between the two groups.

Conclusion: Segmental resection seems to have inferior outcomes as compared to formal left hemicolectomy with higher blood loss, higher leakage rate and post-operative complications.

P42: Memokath^TM prostate stent in patients with refractory urinary retention: The functional stent survival and outcomes

FCH Wong, KW Wong, SK Li, NH Chan, CM Li and CN Tang

Division of Urology, Department of Surgery, Pamela Youde Nethersole Eastern Hospital, 3 Lok Man Road, Chai Wan, Hong Kong

Aim: Memokath^TM prostate stent is an alternative to long-term urinary catheter for patients with refractory urinary retention. Memokath^TM stent insertion is a low-risk and local anaesthesia procedure. The benefits include avoiding operative risks in high-risks patients, and reducing catheter-related complications. This study aimed to evaluate the outcomes of the patients with Memokath^TM stent inserted at our hospital.

Method: We had retrospectively reviewed all patients with Memokath^TM stent inserted at our hospital over a 6-year period from January 2011 to December 2016. The indication was refractory urinary retention in patients not fit for transurethral resection of prostate (TURP). The intentions of stenting were either permanent or for bridging while waiting for resolution or workup of acute medical issues. The primary outcome was the duration of functioning stent. The secondary outcomes were risk factors for stent failure and the stent-related complications rate.

Results: Over the 6-year period, 129 patients with Memokath^TM stent inserted were included. The mean duration of functioning stent was 1399.8days (46.0months). Cerebral condition was associated with stent failure. The stent-related complication rates were: urinary tract infection (0.36), haematuria (0.21), encrustation (0.04) and incontinence (0.04) episodes per stent-year.

Conclusions: Memokath^TM prostate stent is a feasible alternative to patients with refractory urinary retention with high operative risks. The stent can function for a reasonable duration and has fewer complications when compared with long-term urethral catheterisation.

P43: Delay jejunal flap for esophageal reconstruction: A rat model

KC Wong ¹, HT Leong¹, P Ciudad², CY Lu³, PY Chen⁴ and HC Chen²

¹Department of Surgery, North District Hospital, Hong Kong

²Department of Plastic and Reconstructive Surgery, China Medical University

³Department of Neurology and Stroke Center, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan; Department of Nursing, Central Taiwan University of Science and Technology, Taichung, Taiwan

⁴Department of Pathology, China Medical University Hospital, Taichung, Taiwan

Background: Jejunal flap is regarded an inferior choice for esophageal reconstruction due to its poor tolerance to ischemia. Limited by the length of mesentry, vascular anastomosis must be performed for the flap to reach up to neck.

The idea of delayed flap, well described in cutaneous flaps but not intestinal tract, may produce longer and straight jejunal flaps without the need for microvascular anastomosis and be used for upper or total oesophageal reconstructions.

Materials and Method: This study aims to investigate the feasibility of delayed jejunal flaps in a rat model. A segment of jejunum and its vascular pedicle is isolated and placed in a subcutaneous pocket. Serial ligation of vasa-recti are performed at time intervals of 120 hours, in different sequence among the 4 groups: (a) from the most distal one and proceed proximally (b) from the second most distal and proceed proximally (c) from the most proximal and proceed distally (d) control group with no ligation. The segment of jejunal is harvested for analysis including: (1) mucosal injury score, (2) change of cytokines, especially IL-6 and IL-1β, (3) hyper-oxidation of the cellular lipid, (4) the fragmented DNA of apoptotic cells.

Results: Rats in group (b) show lowest mucosal injury score and lower level of cytokines expression, followed by group (c) and group (a).

Conclusion: This study demonstrates the feasibility of applying the delayed flap concept in constructing pedicle jejunal flaps, and providing data on the optimal time interval and sequence of vasa-recti ligation. Further studies are warranted to verify its clinical application.

P44: A single center retrospective clinical study on bezoar intestinal obstruction – 10 years experience

KKF Wong and SK Leung

Department of Surgery, Tuen Mun Hospital, Hong Kong

Background: Bezoar is a rare cause of intestinal obstruction. Early diagnosis can facilitate proper surgical management and recovery.

Aim and Method: This retrospective study reviewed 81 patients who had small bowel obstruction due to bezoars(from 2007-2016) and identified factors associated with surgical outcome.

Results: The average patient age was 65.9 years(range, 31- 95years). The common bezoar locations were the distal ileum(47 cases, 58%) and jejunum(16 cases, 20%). 30 cases(37%) had multi-bezoars, including 13 cases(16%) involving the stomach. All cases involved had phytobezoars. While milking was applied to 39 cases(48.1%), enterotomy was performed in 36 cases (44.4%).6 cases(7.5%) involved small bowel resection. Patients with history of abdominal surgery were more often requiring enterotomy(P=0.012), while patient with virgin abdomen were more often treated with fragmentation and milking (P=0.021).Patient with history of abdominal surgery(P=0.008) or gastric surgery (P=0.016) were more common to receive additional co-procedures during the operation. Post-operative complication rate was similar in who received these three types of operation. Complications (P=0.008) and mortality (P=0.048) were more common in patients with medical co-morbidities (P = 0.008) and complication led to prolong hospital stay (P=0.014). Post-operative complication tends to be more common in whom received additional procedure (extensive adhesiolysis, bypass, cholecystectomy, gastrostomy) (P=0.109).

Conclusion: Bezoar obstruction was most commonly found over the distal ileum. Multiple bezoars condition was also common. Milking and fragmentation was the most commonly performed operation, compared with enterotomy and bowel resection. Post-operative complication rate was similar among patients who received these three types of operation. Complications were statistically more common in patient with medical co-morbidities and tend to be more common in who received additional procedure during the surgery.

P45: Emergency aortic stent-graft treatment in patients with malignant aorto-esophageal fistula is worthwhile

PC Wong, YC Chan, Y Law and SW Cheng

Division of Vascular & Endovascular Surgery, Department of Surgery, University of Hong Kong Medical Centre, South Wing, 14^th Floor K Block, Queen Mary Hospital, Hong Kong.

Aim: To investigate the outcome of emergency aortic stent-graft treatment in patients with malignant aorto-esophageal fistula (AEF).

Methods: Two patients with advanced squamous cell carcinoma of the mid-esophagus were reported. Both patients had esophageal stents in-situ and developed sudden onset massive haematemesis and haemodynamic instability due to primary AEF. An electronic search was performed to identify similar published case reports. A case series was constructed with comparison on the patient’s demographics, tumour status, operation performed, clinical outcome and survival.

Results: Six patients with malignant AEF were reported in this series. Hemostasis was successfully achieved with endovascular aortic stent-graft in all patients. On average, the patients survived for more than three months after the operation with no further septic or haemorrhagic complications. Five out of six patients finally passed away due to terminal malignancy while one patient survived with good recovery.

Conclusion: We emphasize that even when the esophageal tumours are locally advanced, TEVAR (Thoracic endovascular aortic stent-graft repair) should be regarded as the first line treatment of AEF as supported by its relatively low operative mortality and effective control of massive hematemesis. A reasonable prolongation of survival could be achieved even in patients with malignant AEF.

P46: Early experience on arch-last technique in total aortic arch replacement surgery using Gelweave Vascutec 4-branched aortic graft

SKW Yam and HHY Chan

Department of Cardiothoracic Surgery, Queen Elizabeth Hospital

Aim: Total aortic arch replacement remains a complex surgical procedure. Stroke and haemostasis are still challenging issues causing significant morbidity and mortality. Here we investigate the efficacy of total arch replacement with arch-last technique using 4-branched aortic graft.

Methods: Between April 2016 and June 2017, six consecutive patients (age from 30 to 78, mean 51) received total aortic arch replacement using arch-last technique. All patients were put on cardiopulmonary bypass and hypothermic circulatory arrest at 25°C. Selective antegrade cerebral perfusion (SACP), using two Foley catheters to innominate artery and left common carotid artery, was performed for cerebral protection. Aortic arch was resected and distal anastomosis between proximal descending aorta and the aortic graft was performed. Patients were then actively rewarmed to normal body temperature while performing proximal aortic anastomosis. Finally the three supraaortic vessels were anastomosed to the graft in sequence of left subclavian, left common carotid and innominate arteries (Arch-Last). SACP was then off and cardiopulmonary bypass was weaned.

Results: 5 out of 6 patients were done under emergency operation. Pathology includes acute type A aortic dissection (2 cases), acute type A aortic intramural haematoma (2 cases), chronic type A aortic dissection (1 case) and aortic arch aneurysm (1 case). Length of postoperative stay was from 7 to 28 days (mean 20 days). No in-hospital death and no post-operative neurological complications were observed.

Conclusion: Arch-last technique for total arch replacement using 4-branched aortic graft is feasible and safe. It provides a simple and effective way of cerebral protection.

P47: 10-Year survival after breast-conserving surgery plus radiotherapy compared with mastectomy in early stage non-palpable breast cancer: A Chinese population-based study of controversy in survival benefit

R Yao, B Pan and Q Sun

Department of Breast Surgery, Peking Union Medical College Hospital, No.1 Shuaifuyuan Wangfujing, Dongcheng District, Beijing, China

Background: Some studies showed that improved survival for breast-conserving surgery (BCS) plus radiotherapy compared with mastectomy in early breast cancer. As these studies didn’t present long-term overall survival (OS), the effect of BCS might be overestimated. Meanwhile, there is little data about the long-term survival of the screen-detected non-palpable breast cancer (NPBC) with different surgery in Chinese women.

Methods: We included and followed up 410 women who were asymptomatic, screen-detected and diagnosed with primary, invasive NPBC, stage T1/N0-1/M0 breast cancer between January 2001 and December 2014 in Peking Union Medical College Hospital, given either BCS plus radiotherapy or mastectomy. The clinicopathological features, treatment choice, 10-year disease-free survival (DFS) and OS were reviewed.

Results: Of the 410 NPBC patients included in this study, 92 (22.4%) received BCS plus radiotherapy and 318 (77.6%) received mastectomy. The BCS group presented higher rates of younger patients, smaller tumor, positive hormone receptor and endocrine therapy than the mastectomy group. However, BCS group had no significance associated with improved 10-year OS in the whole cohort compared with mastectomy group (p=0.248), even though it showed worse 10-year DFS (p=0.043). And it remained non-significant for all subgroups of different T and N stages (p=0.266).

Conclusion: This population-based study with long term follow-up confirmed that BCS plus radiotherapy didn’t show improved 10-year overall survival compared with mastectomy in early breast cancer. However, these results suggest that BCS plus radiotherapy is at least equivalent to mastectomy with respect to overall survival and may influence treatment decision making for patients with early breast cancer.

P48: Home safe home? Serious complications following foreign body ingestion in paediatric population

F Yeung, PHY Chung, KKY Wong and PKH Tam

Department of Surgery, University of Hong Kong Medical Center, Queen Mary Hospital, Hong Kong

Aim: Accidental foreign body ingestion (FBI) is a common paediatric problem. This study aims to review our experiences in managing children with suspected FBI and elucidate the serious complications following the incidences.

Methods: We performed a retrospective analysis of paediatric patients with suspected FBI admitted to our institution between January 2013 and June 2017. Demographic data, radiological findings, interventions and complications were analysed.

Results: A total of 302 patients with mean age of 5.5 years (Range: 3 months-17 years) were admitted for suspected FBI. The most common foreign body ingested were fish bones (n=224, 74.2%). Three serious complications occurred, in which one girl ingested multiple magnetic beads developed small bowel fistulation and internal herniation requiring laparotomy and partial ileal resection. Another boy accidentally ingested corrosive detergent leading to extensive oesophageal stricture depending upon regular balloon dilatation. Another serious complication occurred in a boy with missed fish bone on first admission and developed retropharyngeal abscess requiring emergency neck incision and drainage with removal of fish bone in the abscess cavity. Radiographs were only able to identify 14.9% (n=45) of all foreign bodies. Upper endoscopy was selectively performed in 15.6% patients (n=47) with persistent symptoms after negative direct laryngoscopy following fish bone ingestion or radiographs showing foreign bodies persisting in oesophagus or stomach.

Conclusion: Serious complications could occur following FBI in children especially in those with magnetic or caustic FBI. High vigilance for missed foreign bodies are necessary and emergency upper endoscopy or computed tomography shall be offered in suspicious cases before occurrence of devastating complications.

P49: Outcome analysis of end-stage renal failure patient on hemodialysis and peritoneal dialysis underwent parathyroidectomy for secondary hyperparathyroidism

KH Yue and KP Wong

Department of Surgery, Queen Mary Hospital

Aim: The outcome between end-stage renal failure patients on hemodialysis and peritoneal dialysis who underwent parathyroidectomy was studied.

Methods: Patients underwent parathyroidectomy from Jan 2008 to Dec 2015 for secondary renal hyperparathyroidism in Queen Mary Hospital were reviewed for short-term and long-term outcomes. Persistent disease is defined as elevation of PTH >800 pg/ml within 6 months after operation; whereas recurrence is defined as elevation of PTH >800 pg/ml after 6 months.

Results: There were total 97 patients underwent parathyroidectomy (HD vs PD; 29 vs 68). The average time of follow-up was 46 month. The rate of hungry bone syndrome were 27.6% in HD group and 23.9% in PD group (p = 0.798). The overall permanent recurrent laryngeal nerve palsy rate was 2.1% (HD vs PD, 0% vs 2.9%, p=1.0).

5 patients had persistent disease (HD 3/29 vs PD 2/68, p=0.156) and 10 patients had recurrence (HD 2/29 vs PD 8/68, p= 0.718). The overall persistent and recurrence rate was 5.1% and 11.1% respectively. The median time to recurrence is 33.5 months. Intraoperative identification of less than 4 parathyroid glands was associated with persistent disease (p=0.01) but not recurrent disease (p=0.599).

Conclusion: The short-term and long-term outcomes between the two groups of patients are similar. Intraoperative identification of all 4 parathyroid glands is essential for lowering the risk of persistent disease.

P50: Re-intervention for patient after endovenous laser therapy for saphenofemoral junction incompetency and great saphenous vein reflux

KH Yue, WC Wong and SH Wong

Department of Surgery, Kwong Wah Hospital

Aim: Endovenous laser therapy combined with below knee stab avulsion is the mainstream of treatment for saphenofemoral junction incompetency and great saphenous vein reflux. The need and burden for additional intervention for recurrent and residual disease after the procedure was not well studied.

Methods: Records of patients underwent endovenous laser therapy with stab avulsion for SFJ incompetency and GSV reflux from Jan 2014 to Jun 2016 were reviewed. Clinical, sonographic and surgical outcome were analyzed per treated limb.

Results: There were total 80 patient and 89 limbs (47 lefts and 42 rights), including 5 patients who had recurrent varicose vein with previous surgical intervention. The median duration of follow-up was 13.5 month (1 - 36 month).

The rate of clinical recurrence was 6.7% (6 limbs). The rate of recanalization of GSV on USG was 13.5% (12 limbs). The rate of residual below knee GSV reflux and residual varicosities was 23.6% (21 limbs).

Total 9 limbs (10.1%) required further intervention by foam sclerotherapy, in which 7 for residual below knee GSV reflux and residual calf varicosities (RR 13.5, p =0.002), and 2 for recanalized GSV (RR 6.01, p=0.013).

Conclusion: The need for further intervention was largely due to residual below knee GSV reflux and residual calf varicosities.

Remarks: Recanalization is defined as detection of trickle flow or complete recanalization on USG. Residual below knee GSV reflux and calf varicosities is defined as detection of such within 6-month after operation. Clinical recurrence is defined as recur of varicose vein or venous ulcer due to recanalization of GSV (by perforator reflux or neovascularization), or development of AASV reflux after 6 months.

P51: Tissue metabolomic profile in occult HBV infection-related hepatocellular carcinoma, using high-resolution magic-angle spinning ¹H NMR spectroscopy

C Cen,^1,2,3 J Yu,^1,2,3 SF Yu,^1,2,3 JM Liu,⁴ YF Ye,^1,2,3 WC Zhang,² L Zhou,^1,2,3 HY Xie^1,2,3 and SS Zheng^1,2,3

¹Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China

²Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, Key Laboratory of Organ Transplantation, Hangzhou, Zhejiang Province, China

³Collaborative Innovation Center for Diagnosis Treatment of Infectious Diseases, Hangzhou, Zhejiang Province, China

⁴Department of Pathology and Molecular Medicine, Faculty of Health Sciences, McMaster University, 1200 Main Street West, Hamilton, ON, L8N 3Z5, Canada

Aim: Hepatitis B virus (HBV) represents a major risk factor for the development of hepatocellular carcinoma (HCC). Occult HBV infection, reflected by hepatitis B surface antigen negative/hepatitis B core antibody positive (HBsAg-/anti-HBc+), is highly prevalent in HCC patient and may play an important role in hepatocarcinogenesis through the expression of oncogenic viral protein. In this study, we aimed to investigate the metabolomic signatures of occult HBV infection-related HCC, to further understand the pathogenesis of this disease.

Methods: Tumor and adjacent non-tumor tissues from 30 HBsAg+/anti-HBc+ HCC patients and 30 HBsAg-/anti-HBc+ HCC patients were analyzed, using high-resolution magic-angle spinning (HRMAS) ¹H NMR spectroscopy. Orthogonal projection to latent structure-discriminant analysis (OPLS-DA) was performed to compare the expression of metabolomic profiles.

Results: Metabolic profile was identified in tissues from all four groups. The level of expression varied between tumor and non-tumor tissues in both HBsAg+/anti-HBc+ and HBsAg-/anti-HBc+ groups, with high sensitivity and specificity (AUC=0.997, 0.975 respectively). Additionally, the contents of hypoxanthine, histidine, phenylalanine, tryptophan were higher in HBsAg+/anti-HBc+ HCC tissues, comparing to HBsAg-/anti-HBc+ HCC tissues (R²X = 0.206, Q² = 0.362, P = 7.0689 × 10⁻⁵), indicating upregulation of protein turnover and nucleotide biosynthesis.

Conclusion: In HCC patients, the tissue metabolomic profile expressed differently between HBsAg+/anti-HBc+ and HBsAg-/anti-HBc+ groups. The novel findings may enlighten our understanding of the pathogenesis of occult HBV infection-related HCC and lead to the further development of appropriate molecular targeted therapy.