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Papers by Adrian Kah Heng Chiow

Research paper thumbnail of Bilateral breast cancer – an Asian perspective

European Journal of Cancer Supplements, 2008

Research paper thumbnail of A rare case of spontaneous common bile duct perforation

HPB, 2018

Conclusion: More conservative approaches such as external drainage of choledochal cyst should be ... more Conclusion: More conservative approaches such as external drainage of choledochal cyst should be considered for pregnant patients with high risk, complete excision of choledochal cyst during hepaticojejunostomy is recommended at the optimal time. Excision of only the extrahepatic part of the cyst has become the accepted form of treatment for type-IV-A cysts. Hepatic resection for a type IV-A choledochal cyst should be considered when the intrahepatic dilatation is confined to one part of the liver We think that lt. lobectomy may be indicated in type IV-A choledochal cyst pts. with an intrahepatic stricture that exist deep in the liver parenchyma.

Research paper thumbnail of Minimally invasive liver resection for huge (≥10 cm) tumors: an international multicenter matched cohort study with regression discontinuity analyses

Hepatobiliary Surgery and Nutrition, 2021

Background: The application and feasibility of minimally invasive liver resection (MILR) for huge... more Background: The application and feasibility of minimally invasive liver resection (MILR) for huge liver tumours (≥10 cm) has not been well documented. Methods: Retrospective analysis of data on 6,617 patients who had MILR for liver tumours were gathered from 21 international centers between 2009-2019. Huge tumors and large tumors were defined as tumors with a size ≥10.0 cm and 3.0-9.9 cm based on histology, respectively. 1:1 coarsened exact-matching (CEM) and 1:2 Mahalanobis distance-matching (MDM) was performed according to clinically-selected variables. Regression discontinuity analyses were performed as an additional line of sensitivity analysis to estimate local treatment effects at the 10-cm tumor size cutoff. Results: Of 2,890 patients with tumours ≥3 cm, there were 205 huge tumors. After 1:1 CEM, 174 huge tumors were matched to 174 large tumors; and after 1:2 MDM, 190 huge tumours were matched to 380 large tumours. There was significantly and consistently increased intraoperative blood loss, frequency in the application of Pringle maneuver, major morbidity and postoperative stay in the huge tumour group compared to the large tumour group after both 1:1 CEM and 1:2 MDM. These findings were reinforced in RD analyses. Intraoperative blood transfusion rate and open conversion rate were significantly higher in the huge tumor group after only 1:2 MDM but not 1:1 CEM. Conclusions: MILR for huge tumours can be safely performed in expert centers It is an operation with substantial complexity and high technical requirement, with worse perioperative outcomes compared to MILR for large tumors, therefore judicious patient selection is pivotal.

Research paper thumbnail of Combined HPB with multi-quadrant, multi-visceral resection with robotic Xi : our early experience

HPB, 2018

Introduction: Earlier iterations of the Robotic Da Vinci system (S, Si) had been limited by bulky... more Introduction: Earlier iterations of the Robotic Da Vinci system (S, Si) had been limited by bulky robotic arms and need for repositioning of the robotic cart for multi-quadrant, multi-visceral surgery. The introduction of the Da Vinci Xi with its slimmer arm profile, longer reach and rotating boom mounted arms has simplified the docking procedure allowing for single docking even for complex multi-quadrant surgery. We present our early experience using the Da Vinci Xi for various hepato-pancreaticobiliary (HPB) surgeries combined with other sub-specialities for multi-visceral resection. Methods: A retrospective review of a prospectively maintained database of robotic surgeries performed in CGH since February 2015 to November 2017 was done. All cases involving combined multi sub-speciality synchronous surgery was reviewed and anonymised data was extracted for analysis. Results: 360 robotic cases had been performed in CGH during the study duration covering colorectal, urology, HPB and upper gastrointestinal surgery. 11 cases were multi-visceral, multi-quadrant surgeries of which 4 were HPB combined with another specialty. 2 were left lateral sectionectomies of liver with anterior resection for metastatic colorectal cancer, 1 Whipple operation for periampullary carcinoma with right partial nephrectomy for renal cell carcinoma(RCC) and lastly cholecystectomy with partial nephrectomy for RCC. All margins were clear. There was no 90 day/inpatient mortality in the entire cohort of 11 patients. Conclusion: Complex multi-quadrant, multi-visceral surgeries are feasible and safe with the Da Vinci Xi. More comparative studies with larger cohorts are needed to confirm the benefit of this modality versus conventional laparoscopic surgery.

Research paper thumbnail of Inguinal Hernias: A Current Review of an Old Problem

Singapore General Hospital Proceedings

AbstRACt The repair of groin hernias are amongst the most commonly performed procedures by the ge... more AbstRACt The repair of groin hernias are amongst the most commonly performed procedures by the general surgeon today, with almost as many types of repairs as there are hernias. Inguinal hernias account for 75% of all abdominal wall hernias with a lifetime risk of 27% in men and 3% in women 1 . Repair techniques have evolved from open suture methods to mesh repairs done either open or laparoscopically, translating to improved patient care and decreasing complications associated with hernia repair. This article is intended to provide an overview of the presentation and latest evidence based guidelines for the management of inguinal hernias.

Research paper thumbnail of Isolated tuberculosis of the pancreas mimicking a pancreatic tumor with concomitant choledocholithiasis

International Journal of Hepatobiliary and Pancreatic Diseases, 2014

Research paper thumbnail of Rare cause of acute surgical abdomen with free intraperitoneal air: Spontaneous perforated pyometra. A report of 2 cases

American Journal of Case Reports, 2012

The acute abdomen accounts for up to 40% of all emergency surgical hospital admissions and a larg... more The acute abdomen accounts for up to 40% of all emergency surgical hospital admissions and a large proportion are secondary to gastrointestinal perforation. Studies have shown the superiority of the abdominal CT over upright chest radiographs in demonstrating free intraperitoneal air. Spontaneous perforated pyometra is a rare cause of the surgical acute abdomen with free intraperitoneal air. Only 38 cases have been reported worldwide. We report 2 cases of spontaneously perforated pyometra in our hospital's general surgery department. Both underwent exploratory laparotomy: one had a total hysterectomy and bilateral salpingo-oophorectomy, while the other had an evacuation of the uterine cavity, primary repair of uterine perforation and a peritoneal washout. A literature search was conducted and all reported cases reviewed in order to describe the clinical presentations and management of the condition. Of the 40 cases to date, including 2 of our cases, the most common presenting symptoms were abdominal pain (97.5%), fever (37.5%) and vomiting (25.0%). The main indication for exploratory laparotomy was pneumoperitoneum (97.5%). Pyometra is an unusual but serious condition in elderly women presenting with an acute abdomen. A high index of suspicion is needed to make the appropriate diagnosis.

Research paper thumbnail of Recurrent Pyogenic Cholangitis: Disease Characteristics and Patterns of Recurrence

ISRN Surgery, 2013

Recurrent pyogenic cholangitis (RPC) is characterized by repeated infections of the biliary syste... more Recurrent pyogenic cholangitis (RPC) is characterized by repeated infections of the biliary system with the formation of stones and strictures. The management aims are to treat acute cholangitis, clear the biliary ductal debris and calculi, and eliminate predisposing factors of bile stasis. Operative options include hepatectomy and biliary drainage procedures or a combination of both; nonoperative options include endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) guided procedures. This current study compares the operative and the nonoperative management outcomes in patients with RPC in 80 consecutive patients. In addition, we aim to evaluate our approach to the management of RPC over the past decade, according to the various degrees of severity and extent of the disease, and identify the patterns of recurrence in this complex clinical condition. Initial failure rate in terms of residual stone of operative compared with nonoperative treatment was 10.2% versus 32.3% ( = 0.020). Long-term failure rate for operative compared with non-operative treatment was 20.4% versus 61.3% ( = 0.010). Based on multivariate logistic regression, the only significant factors associated with failure were bilaterality of disease (OR: 8.101, = 0.007) and nonoperative treatment (OR: 26.843, = 0.001). The median time to failure of the operative group was 48 months as compared to 20 months in the nonoperative group ( < 0.010). Thus operative treatment is a durable option in long-term resolution of disease. Hepatectomy is the preferred option to prevent recurrent disease. However, biliary drainage procedures are also an effective treatment option. The utility of nonoperative treatment can achieve a reasonable duration of disease free interval with minimal complications, albeit inferior to operative management.

Research paper thumbnail of Bilateral breast cancer – an Asian perspective

European Journal of Cancer Supplements, 2008

Research paper thumbnail of A rare case of spontaneous common bile duct perforation

HPB, 2018

Conclusion: More conservative approaches such as external drainage of choledochal cyst should be ... more Conclusion: More conservative approaches such as external drainage of choledochal cyst should be considered for pregnant patients with high risk, complete excision of choledochal cyst during hepaticojejunostomy is recommended at the optimal time. Excision of only the extrahepatic part of the cyst has become the accepted form of treatment for type-IV-A cysts. Hepatic resection for a type IV-A choledochal cyst should be considered when the intrahepatic dilatation is confined to one part of the liver We think that lt. lobectomy may be indicated in type IV-A choledochal cyst pts. with an intrahepatic stricture that exist deep in the liver parenchyma.

Research paper thumbnail of Minimally invasive liver resection for huge (≥10 cm) tumors: an international multicenter matched cohort study with regression discontinuity analyses

Hepatobiliary Surgery and Nutrition, 2021

Background: The application and feasibility of minimally invasive liver resection (MILR) for huge... more Background: The application and feasibility of minimally invasive liver resection (MILR) for huge liver tumours (≥10 cm) has not been well documented. Methods: Retrospective analysis of data on 6,617 patients who had MILR for liver tumours were gathered from 21 international centers between 2009-2019. Huge tumors and large tumors were defined as tumors with a size ≥10.0 cm and 3.0-9.9 cm based on histology, respectively. 1:1 coarsened exact-matching (CEM) and 1:2 Mahalanobis distance-matching (MDM) was performed according to clinically-selected variables. Regression discontinuity analyses were performed as an additional line of sensitivity analysis to estimate local treatment effects at the 10-cm tumor size cutoff. Results: Of 2,890 patients with tumours ≥3 cm, there were 205 huge tumors. After 1:1 CEM, 174 huge tumors were matched to 174 large tumors; and after 1:2 MDM, 190 huge tumours were matched to 380 large tumours. There was significantly and consistently increased intraoperative blood loss, frequency in the application of Pringle maneuver, major morbidity and postoperative stay in the huge tumour group compared to the large tumour group after both 1:1 CEM and 1:2 MDM. These findings were reinforced in RD analyses. Intraoperative blood transfusion rate and open conversion rate were significantly higher in the huge tumor group after only 1:2 MDM but not 1:1 CEM. Conclusions: MILR for huge tumours can be safely performed in expert centers It is an operation with substantial complexity and high technical requirement, with worse perioperative outcomes compared to MILR for large tumors, therefore judicious patient selection is pivotal.

Research paper thumbnail of Combined HPB with multi-quadrant, multi-visceral resection with robotic Xi : our early experience

HPB, 2018

Introduction: Earlier iterations of the Robotic Da Vinci system (S, Si) had been limited by bulky... more Introduction: Earlier iterations of the Robotic Da Vinci system (S, Si) had been limited by bulky robotic arms and need for repositioning of the robotic cart for multi-quadrant, multi-visceral surgery. The introduction of the Da Vinci Xi with its slimmer arm profile, longer reach and rotating boom mounted arms has simplified the docking procedure allowing for single docking even for complex multi-quadrant surgery. We present our early experience using the Da Vinci Xi for various hepato-pancreaticobiliary (HPB) surgeries combined with other sub-specialities for multi-visceral resection. Methods: A retrospective review of a prospectively maintained database of robotic surgeries performed in CGH since February 2015 to November 2017 was done. All cases involving combined multi sub-speciality synchronous surgery was reviewed and anonymised data was extracted for analysis. Results: 360 robotic cases had been performed in CGH during the study duration covering colorectal, urology, HPB and upper gastrointestinal surgery. 11 cases were multi-visceral, multi-quadrant surgeries of which 4 were HPB combined with another specialty. 2 were left lateral sectionectomies of liver with anterior resection for metastatic colorectal cancer, 1 Whipple operation for periampullary carcinoma with right partial nephrectomy for renal cell carcinoma(RCC) and lastly cholecystectomy with partial nephrectomy for RCC. All margins were clear. There was no 90 day/inpatient mortality in the entire cohort of 11 patients. Conclusion: Complex multi-quadrant, multi-visceral surgeries are feasible and safe with the Da Vinci Xi. More comparative studies with larger cohorts are needed to confirm the benefit of this modality versus conventional laparoscopic surgery.

Research paper thumbnail of Inguinal Hernias: A Current Review of an Old Problem

Singapore General Hospital Proceedings

AbstRACt The repair of groin hernias are amongst the most commonly performed procedures by the ge... more AbstRACt The repair of groin hernias are amongst the most commonly performed procedures by the general surgeon today, with almost as many types of repairs as there are hernias. Inguinal hernias account for 75% of all abdominal wall hernias with a lifetime risk of 27% in men and 3% in women 1 . Repair techniques have evolved from open suture methods to mesh repairs done either open or laparoscopically, translating to improved patient care and decreasing complications associated with hernia repair. This article is intended to provide an overview of the presentation and latest evidence based guidelines for the management of inguinal hernias.

Research paper thumbnail of Isolated tuberculosis of the pancreas mimicking a pancreatic tumor with concomitant choledocholithiasis

International Journal of Hepatobiliary and Pancreatic Diseases, 2014

Research paper thumbnail of Rare cause of acute surgical abdomen with free intraperitoneal air: Spontaneous perforated pyometra. A report of 2 cases

American Journal of Case Reports, 2012

The acute abdomen accounts for up to 40% of all emergency surgical hospital admissions and a larg... more The acute abdomen accounts for up to 40% of all emergency surgical hospital admissions and a large proportion are secondary to gastrointestinal perforation. Studies have shown the superiority of the abdominal CT over upright chest radiographs in demonstrating free intraperitoneal air. Spontaneous perforated pyometra is a rare cause of the surgical acute abdomen with free intraperitoneal air. Only 38 cases have been reported worldwide. We report 2 cases of spontaneously perforated pyometra in our hospital&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s general surgery department. Both underwent exploratory laparotomy: one had a total hysterectomy and bilateral salpingo-oophorectomy, while the other had an evacuation of the uterine cavity, primary repair of uterine perforation and a peritoneal washout. A literature search was conducted and all reported cases reviewed in order to describe the clinical presentations and management of the condition. Of the 40 cases to date, including 2 of our cases, the most common presenting symptoms were abdominal pain (97.5%), fever (37.5%) and vomiting (25.0%). The main indication for exploratory laparotomy was pneumoperitoneum (97.5%). Pyometra is an unusual but serious condition in elderly women presenting with an acute abdomen. A high index of suspicion is needed to make the appropriate diagnosis.

Research paper thumbnail of Recurrent Pyogenic Cholangitis: Disease Characteristics and Patterns of Recurrence

ISRN Surgery, 2013

Recurrent pyogenic cholangitis (RPC) is characterized by repeated infections of the biliary syste... more Recurrent pyogenic cholangitis (RPC) is characterized by repeated infections of the biliary system with the formation of stones and strictures. The management aims are to treat acute cholangitis, clear the biliary ductal debris and calculi, and eliminate predisposing factors of bile stasis. Operative options include hepatectomy and biliary drainage procedures or a combination of both; nonoperative options include endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) guided procedures. This current study compares the operative and the nonoperative management outcomes in patients with RPC in 80 consecutive patients. In addition, we aim to evaluate our approach to the management of RPC over the past decade, according to the various degrees of severity and extent of the disease, and identify the patterns of recurrence in this complex clinical condition. Initial failure rate in terms of residual stone of operative compared with nonoperative treatment was 10.2% versus 32.3% ( = 0.020). Long-term failure rate for operative compared with non-operative treatment was 20.4% versus 61.3% ( = 0.010). Based on multivariate logistic regression, the only significant factors associated with failure were bilaterality of disease (OR: 8.101, = 0.007) and nonoperative treatment (OR: 26.843, = 0.001). The median time to failure of the operative group was 48 months as compared to 20 months in the nonoperative group ( < 0.010). Thus operative treatment is a durable option in long-term resolution of disease. Hepatectomy is the preferred option to prevent recurrent disease. However, biliary drainage procedures are also an effective treatment option. The utility of nonoperative treatment can achieve a reasonable duration of disease free interval with minimal complications, albeit inferior to operative management.