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Papers by Muhammed A Memon

Research paper thumbnail of Postgraduate Diploma and Master (M.A.) in Clinical Education

Research paper thumbnail of Improving Statistical Inference with uncertain non-sample prior information

In the classical inference, the observed sample data is the only source of information. The Bayes... more In the classical inference, the observed sample data is the only source of information. The Bayesian inferential methods assume prior distribution of the underlying model parameters to combine with sample data. Often non-sample prior information (NSPI) on the value of the model parameters is available from previous studies or expert knowledge which could be used along with the sample data to improve the quality of statistical inference. Obviously the NSPI is not always correct and hence there is uncertainty in the suspected value of the parameter. Any such uncertainty can be removed by conducting an appropriate statistical test, and the quality of statistical inference can be improved by including the outcome of the test in the inferential procedure. This paper provides the underlying methodology to illustrate the process and include an example to demonstrate its application.

Research paper thumbnail of Response to letter

Research paper thumbnail of Operative Surgery Vivas for the MRCS, Ali Abbassian, Sarah Krishnanandan, Christopher James. Cambridge University Press, UK. (164 pp., £ 21.99 or $ 39.99), ISBN: 0521674417

Research paper thumbnail of Emergency Intraperitoneal Onlay Mesh Repair of Incarcerated Spigelian Hernia

JSLS, Journal of the Society of Laparoendoscopic Surgeons, 2010

Research paper thumbnail of Preliminary results of meta-analysis of endoscopic retrograde cholangiopancreatography (ERCP) versus conservative treatment for gall stone pancreatitis

Research paper thumbnail of Preliminary results of meta-analysis of laparoscopic and open inguinal hernia repair

Research paper thumbnail of Meta-analysis of laparoscopic posterior and anterior fundoplication for gastro-oesophageal reflux disease

Research paper thumbnail of Handoscopic Surgery

Archives of Surgery, 1999

Research paper thumbnail of Open Disclosure Program: Should All Trainee Surgeons Be Educated?

ANZ Journal of Surgery, 2009

Research paper thumbnail of Effect of Immune-Enhanced Supplemented Formulas in Perioperative Outcomes: A Meta-Analysis

ANZ Journal of Surgery, 2009

Research paper thumbnail of Using DVDS to Enhance the Teaching of Human Anatomy

ANZ Journal of Surgery, 2009

ABSTRACT One of the recognised problems in learning anatomy comes from trying to form a three dim... more ABSTRACT One of the recognised problems in learning anatomy comes from trying to form a three dimensional mental picture without three dimensional learning tools. Few people are able to create mental images that are three dimensional by looking at either pictures in books, slides on a screen or static images on a computer monitor; all these modalities support a learning experience that is in only two dimensions. While it is considered that the best three dimensional learning experience comes from dissecting the human body itself, today, access to that facility is becoming more difficult. To overcome these problems the authors have reviewed a DVD selection that presents freshly dissected human anatomical specimens in three dimensions. The DVDs are based on cadaveric material which has not been embalmed so that tissues retain the colour, texture and mobility of the living body. The dissections used have also been undertaken by skilled clinical anatomists, using the finest surgical and even micro surgical techniques. Each DVD has a clear, clear concise narration throughout, making them a saving aid to first time learning, an effective way to build on existing knowledge of anatomy, an efficient tool for revision and, for clinicians in training and in practice, a swift renewal of anatomical knowledge. The authors’ succinct appraisal of the DVDs reviewed has demonstrated that they are a means of enhancing the teaching of anatomy and facilitation of learning.

Research paper thumbnail of Delayed Presentation of Duodenal Hematoma and Acute Pancreatitis Following a Seatbelt Injury

ANZ Journal of Surgery, 2009

Research paper thumbnail of Does the Use of Dedicated Ranson's Criteria Improve Patient Outcome?

ANZ Journal of Surgery, 2009

Research paper thumbnail of Laparoscopic Anterior Versus Posterior Fundoplication for Gastroesophageal Reflux Disease

Annals of Surgery, 2011

To compare short- and long-term outcome after laparoscopic anterior fundoplication (LAF) versus p... more To compare short- and long-term outcome after laparoscopic anterior fundoplication (LAF) versus posterior fundoplication (LPF) through a systematic review and meta-analysis of randomized clinical trials (RCTs). LPF is currently considered the surgical therapy of choice for gastroesophageal reflux disease (GERD). Alternatively, LAF has been alleged to reduce troublesome dysphagia and gas-related symptoms. Four electronic databases (MEDLINE, EMBASE, Cochrane Library, and ISI web of Knowledge CPCI-S) were searched for RCTs comparing primary LAF versus LPF for GERD. The methodological quality was evaluated to assess bias risk. Primary outcomes were esophageal acid exposure time, heartburn, Dakkak dysphagia score (0-45) and reoperation rate. Short- and long-term results were pooled separately in meta-analyses as risk ratios (RRs) and weighted mean differences (WMDs). Eleven reports on 7 eligible RCTs (anterior vs. posterior total [n = 5]; anterior vs. posterior partial [n = 2]) comparing LAF (n = 345) versus LPF (n = 338) were identified. Short-term (6-12 months) esophageal acid exposure time (3.3% vs. 0.8%: WMD 2.04; 95% confidence interval [CI] [0.84-3.24]; P < 0.001), heartburn (21% vs. 8%; RR 2.71; 95%CI [1.72-4.26]; P < 0.001) and reoperation rate (8% vs. 4%; RR 1.94; 95%CI [0.97-3.87]; P = 0.06) were higher after LAF. In contrast, the Dakkak dysphagia score was lower after LAF (2.5 vs. 5.7; WMD -2.87; 95%CI [-3.88 to -1.87]; P < 0.001). There were no short-term differences in prevalence of esophagitis, regurgitation and perioperative outcomes. The higher rate of heartburn after LAF persisted during long-term (2-10 years) follow-up (31% vs. 14%; RR 2.15; 95% CI [1.49-3.09]; P < 0.001) with more PPI use (25% vs. 10%; RR 2.53; 95% CI [1.40-4.45]; P = 0.002). The long-term reoperation rate was twice as high after LAF (10% vs. 5%; RR 2.12; 95% CI [1.07-4.21]; P = 0.03). Long-term Dakkak dysphagia scores, inability to belch, gas bloating and satisfaction were not different. Esophageal acid exposure time and the prevalence of heartburn are higher after LAF compared with LPF. In the short-term this is counterbalanced by less severe dysphagia. However, dysphagia scores…

Research paper thumbnail of Surgical e-learning: validation of multi-media, web-based lectures

Research paper thumbnail of Lung Herniation Secondary to Minimally Invasive Direct Coronary Artery Bypass Grafting

The Annals of Thoracic Surgery, 1998

Lung herniation after thoracotomy is rare. We report a 66-year-old man who presented with this co... more Lung herniation after thoracotomy is rare. We report a 66-year-old man who presented with this complication after undergoing attempted minimally invasive direct coronary artery bypass grafting. The defect was repaired with a composite of Marlex mesh and methyl methacrylate.

Research paper thumbnail of Meta-Analysis of Early Endoscopic Retrograde Cholangiopancreatography (ERCP)±Endoscopic Sphincterotomy (ES) Versus Conservative Management for Gallstone Pancreatitis (GSP).

Surg Laparosc Endosc Percutan Tech, Mar 20, 2015

CONTEXT: The utility of early endoscopic retrograde cholangiopancreatography (ERCP)±endoscopic... more CONTEXT:

The utility of early endoscopic retrograde cholangiopancreatography (ERCP)±endoscopic sphincterotomy (ES) in the treatment of gallstone pancreatitis (GSP) is still contentious.
OBJECTIVES:

The aim was to conduct a meta-analysis of randomized controlled trials (RCTs) investigating the treatment of GSP by early ERCP±ES versus conservative management and analyzing the patient outcomes.
DATA SOURCES:

A search of Medline, Embase, Science Citation Index, Current Contents, PubMed, and the Cochrane Database of Systematic Reviews identified all RCTs comparing early ERCP to conservative management in GSP published between January 1970 and January 2014. Search terms included "Endoscopic retrograde cholangiopancreatography (ERCP)"; "Endoscopic sphincterotomy"; "Gallstones"; "Bile duct stones"; "Gallstone pancreatitis"; "Biliary pancreatitis"; "Randomize/Randomised controlled trials"; "Conservative management/treatment"; "Human"; "English."
STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS:

Only prospective RCTs comparing early intervention (ie, between 24 and 72 h) with ERCP±ES versus conservative management in GSP were included.
STUDY APPRAISAL AND SYNTHESIS METHODS:

Data extraction and critical appraisal was carried out independently by 2 authors (M.J.B. and M.A.M.) using predefined data fields. Variables analyzed included severity of pancreatitis (mild or severe), overall mortality, overall complications which included pseudocyst formation, organ failure (renal, respiratory, and cardiac), abnormal coagulation, biliary sepsis, and development of pancreatic abscess/phlegmon. The quality of RCTs was assessed using Jadad's scoring system. Random-effects model was used to calculate the outcomes of both binary and continuous data. Heterogeneity among the outcome variables of these trials was determined by the Cochran Q statistic and I index. The meta-analysis was prepared in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines.
RESULTS:

Eleven RCTs consisting of 1314 patients (conservative management=662, ERCP=652) were analyzed. There was a near significant decrease in mortality for ERCP group compared with conservatively managed patients with severe pancreatitis [odds ratio (OR) 0.45; 95% confidence interval (CI), 0.19, 1.09; P=0.08]. In patients with mild pancreatitis, mortality results were comparable for both groups (OR 0.66; 95% CI, 0.02, 28.75; P=0.83). Overall complications were significantly reduced in the ERCP group in severe pancreatic patients (OR 0.32; 95% CI, 0.17, 0.61; P=0.00). In those with mild disease, a strong trend to decreased complications in the ERCP group was seen, however, this was not significant (OR 0.67; 95% CI, 0.43, 1.03; P=0.06).
CONCLUSIONS:

This meta-analysis demonstrates a significant decrease in complications in patients with severe GSP managed with early ERCP/ES compared with conservative management. As far as the mortality is concerned, no significant decrease was observed in mortality even in severe GSP patients treated with early ERCP/ES.

Research paper thumbnail of Rectus sheath haematoma: a rare presentation of non-contact strenuous exercises

Rectus sheath haematoma (RSH) is a well-documented but uncommon clinical condition. It is usually... more Rectus sheath haematoma (RSH) is a well-documented but
uncommon clinical condition. It is usually a self-limiting condition but can present as a life-threatening emergency. RSH after noncontact vigorous exercise is unknown. Two such cases secondary to yoga and laughter therapy sessions, respectively, are reported. One of them required surgical intervention, whereas the other was successfully treated conservatively.

Research paper thumbnail of De Garengeot hernia: an analysis of our experience.

AIM: The presence of a vermiform appendix in a femoral hernia sac is termed De Garengeot hernia.... more AIM:

The presence of a vermiform appendix in a femoral hernia sac is termed De Garengeot hernia. It may present as a tender and/or erythematous groin swelling and is often misdiagnosed as an incarcerated or strangulated femoral hernia. The purpose of this study is to review the management of De Garengeot hernia at a single institution since 1991.

MATERIALS AND METHODS:

A retrospective analysis of seven consecutive patients operated upon at our institution from 1991 to 2006 with De Garengeot hernia was undertaken. Patients' demographics, treatment performed and postoperative outcome were analysed.

RESULTS:

There were three men and four women. The median age was 55 years. None of the patients were diagnosed preoperatively. The commonest presenting symptom was painful groin swelling. All patients therefore underwent emergency surgery with a presumptive diagnosis of either incarcerated or strangulated femoral hernia. Operative findings included four normal appendices, two inflamed appendices and one perforated appendix in the femoral hernial sac. Patients with normal appendix (n = 4) had mesh hernia repair without an appendicectomy. The rest of the patients (n = 3) with abnormal appendix underwent emergency open appendicectomy followed by sutured hernia repair. We had no deaths in this series and one minor wound infection. No recurrent hernia has been detected to date.

CONCLUSION:

Inflammation of the appendix determines the type of hernia repair and surgical approach. Incidental appendicectomy in the case of a normal appendix is not preferred.

Research paper thumbnail of Postgraduate Diploma and Master (M.A.) in Clinical Education

Research paper thumbnail of Improving Statistical Inference with uncertain non-sample prior information

In the classical inference, the observed sample data is the only source of information. The Bayes... more In the classical inference, the observed sample data is the only source of information. The Bayesian inferential methods assume prior distribution of the underlying model parameters to combine with sample data. Often non-sample prior information (NSPI) on the value of the model parameters is available from previous studies or expert knowledge which could be used along with the sample data to improve the quality of statistical inference. Obviously the NSPI is not always correct and hence there is uncertainty in the suspected value of the parameter. Any such uncertainty can be removed by conducting an appropriate statistical test, and the quality of statistical inference can be improved by including the outcome of the test in the inferential procedure. This paper provides the underlying methodology to illustrate the process and include an example to demonstrate its application.

Research paper thumbnail of Response to letter

Research paper thumbnail of Operative Surgery Vivas for the MRCS, Ali Abbassian, Sarah Krishnanandan, Christopher James. Cambridge University Press, UK. (164 pp., £ 21.99 or $ 39.99), ISBN: 0521674417

Research paper thumbnail of Emergency Intraperitoneal Onlay Mesh Repair of Incarcerated Spigelian Hernia

JSLS, Journal of the Society of Laparoendoscopic Surgeons, 2010

Research paper thumbnail of Preliminary results of meta-analysis of endoscopic retrograde cholangiopancreatography (ERCP) versus conservative treatment for gall stone pancreatitis

Research paper thumbnail of Preliminary results of meta-analysis of laparoscopic and open inguinal hernia repair

Research paper thumbnail of Meta-analysis of laparoscopic posterior and anterior fundoplication for gastro-oesophageal reflux disease

Research paper thumbnail of Handoscopic Surgery

Archives of Surgery, 1999

Research paper thumbnail of Open Disclosure Program: Should All Trainee Surgeons Be Educated?

ANZ Journal of Surgery, 2009

Research paper thumbnail of Effect of Immune-Enhanced Supplemented Formulas in Perioperative Outcomes: A Meta-Analysis

ANZ Journal of Surgery, 2009

Research paper thumbnail of Using DVDS to Enhance the Teaching of Human Anatomy

ANZ Journal of Surgery, 2009

ABSTRACT One of the recognised problems in learning anatomy comes from trying to form a three dim... more ABSTRACT One of the recognised problems in learning anatomy comes from trying to form a three dimensional mental picture without three dimensional learning tools. Few people are able to create mental images that are three dimensional by looking at either pictures in books, slides on a screen or static images on a computer monitor; all these modalities support a learning experience that is in only two dimensions. While it is considered that the best three dimensional learning experience comes from dissecting the human body itself, today, access to that facility is becoming more difficult. To overcome these problems the authors have reviewed a DVD selection that presents freshly dissected human anatomical specimens in three dimensions. The DVDs are based on cadaveric material which has not been embalmed so that tissues retain the colour, texture and mobility of the living body. The dissections used have also been undertaken by skilled clinical anatomists, using the finest surgical and even micro surgical techniques. Each DVD has a clear, clear concise narration throughout, making them a saving aid to first time learning, an effective way to build on existing knowledge of anatomy, an efficient tool for revision and, for clinicians in training and in practice, a swift renewal of anatomical knowledge. The authors’ succinct appraisal of the DVDs reviewed has demonstrated that they are a means of enhancing the teaching of anatomy and facilitation of learning.

Research paper thumbnail of Delayed Presentation of Duodenal Hematoma and Acute Pancreatitis Following a Seatbelt Injury

ANZ Journal of Surgery, 2009

Research paper thumbnail of Does the Use of Dedicated Ranson's Criteria Improve Patient Outcome?

ANZ Journal of Surgery, 2009

Research paper thumbnail of Laparoscopic Anterior Versus Posterior Fundoplication for Gastroesophageal Reflux Disease

Annals of Surgery, 2011

To compare short- and long-term outcome after laparoscopic anterior fundoplication (LAF) versus p... more To compare short- and long-term outcome after laparoscopic anterior fundoplication (LAF) versus posterior fundoplication (LPF) through a systematic review and meta-analysis of randomized clinical trials (RCTs). LPF is currently considered the surgical therapy of choice for gastroesophageal reflux disease (GERD). Alternatively, LAF has been alleged to reduce troublesome dysphagia and gas-related symptoms. Four electronic databases (MEDLINE, EMBASE, Cochrane Library, and ISI web of Knowledge CPCI-S) were searched for RCTs comparing primary LAF versus LPF for GERD. The methodological quality was evaluated to assess bias risk. Primary outcomes were esophageal acid exposure time, heartburn, Dakkak dysphagia score (0-45) and reoperation rate. Short- and long-term results were pooled separately in meta-analyses as risk ratios (RRs) and weighted mean differences (WMDs). Eleven reports on 7 eligible RCTs (anterior vs. posterior total [n = 5]; anterior vs. posterior partial [n = 2]) comparing LAF (n = 345) versus LPF (n = 338) were identified. Short-term (6-12 months) esophageal acid exposure time (3.3% vs. 0.8%: WMD 2.04; 95% confidence interval [CI] [0.84-3.24]; P < 0.001), heartburn (21% vs. 8%; RR 2.71; 95%CI [1.72-4.26]; P < 0.001) and reoperation rate (8% vs. 4%; RR 1.94; 95%CI [0.97-3.87]; P = 0.06) were higher after LAF. In contrast, the Dakkak dysphagia score was lower after LAF (2.5 vs. 5.7; WMD -2.87; 95%CI [-3.88 to -1.87]; P < 0.001). There were no short-term differences in prevalence of esophagitis, regurgitation and perioperative outcomes. The higher rate of heartburn after LAF persisted during long-term (2-10 years) follow-up (31% vs. 14%; RR 2.15; 95% CI [1.49-3.09]; P < 0.001) with more PPI use (25% vs. 10%; RR 2.53; 95% CI [1.40-4.45]; P = 0.002). The long-term reoperation rate was twice as high after LAF (10% vs. 5%; RR 2.12; 95% CI [1.07-4.21]; P = 0.03). Long-term Dakkak dysphagia scores, inability to belch, gas bloating and satisfaction were not different. Esophageal acid exposure time and the prevalence of heartburn are higher after LAF compared with LPF. In the short-term this is counterbalanced by less severe dysphagia. However, dysphagia scores…

Research paper thumbnail of Surgical e-learning: validation of multi-media, web-based lectures

Research paper thumbnail of Lung Herniation Secondary to Minimally Invasive Direct Coronary Artery Bypass Grafting

The Annals of Thoracic Surgery, 1998

Lung herniation after thoracotomy is rare. We report a 66-year-old man who presented with this co... more Lung herniation after thoracotomy is rare. We report a 66-year-old man who presented with this complication after undergoing attempted minimally invasive direct coronary artery bypass grafting. The defect was repaired with a composite of Marlex mesh and methyl methacrylate.

Research paper thumbnail of Meta-Analysis of Early Endoscopic Retrograde Cholangiopancreatography (ERCP)±Endoscopic Sphincterotomy (ES) Versus Conservative Management for Gallstone Pancreatitis (GSP).

Surg Laparosc Endosc Percutan Tech, Mar 20, 2015

CONTEXT: The utility of early endoscopic retrograde cholangiopancreatography (ERCP)±endoscopic... more CONTEXT:

The utility of early endoscopic retrograde cholangiopancreatography (ERCP)±endoscopic sphincterotomy (ES) in the treatment of gallstone pancreatitis (GSP) is still contentious.
OBJECTIVES:

The aim was to conduct a meta-analysis of randomized controlled trials (RCTs) investigating the treatment of GSP by early ERCP±ES versus conservative management and analyzing the patient outcomes.
DATA SOURCES:

A search of Medline, Embase, Science Citation Index, Current Contents, PubMed, and the Cochrane Database of Systematic Reviews identified all RCTs comparing early ERCP to conservative management in GSP published between January 1970 and January 2014. Search terms included "Endoscopic retrograde cholangiopancreatography (ERCP)"; "Endoscopic sphincterotomy"; "Gallstones"; "Bile duct stones"; "Gallstone pancreatitis"; "Biliary pancreatitis"; "Randomize/Randomised controlled trials"; "Conservative management/treatment"; "Human"; "English."
STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS:

Only prospective RCTs comparing early intervention (ie, between 24 and 72 h) with ERCP±ES versus conservative management in GSP were included.
STUDY APPRAISAL AND SYNTHESIS METHODS:

Data extraction and critical appraisal was carried out independently by 2 authors (M.J.B. and M.A.M.) using predefined data fields. Variables analyzed included severity of pancreatitis (mild or severe), overall mortality, overall complications which included pseudocyst formation, organ failure (renal, respiratory, and cardiac), abnormal coagulation, biliary sepsis, and development of pancreatic abscess/phlegmon. The quality of RCTs was assessed using Jadad's scoring system. Random-effects model was used to calculate the outcomes of both binary and continuous data. Heterogeneity among the outcome variables of these trials was determined by the Cochran Q statistic and I index. The meta-analysis was prepared in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines.
RESULTS:

Eleven RCTs consisting of 1314 patients (conservative management=662, ERCP=652) were analyzed. There was a near significant decrease in mortality for ERCP group compared with conservatively managed patients with severe pancreatitis [odds ratio (OR) 0.45; 95% confidence interval (CI), 0.19, 1.09; P=0.08]. In patients with mild pancreatitis, mortality results were comparable for both groups (OR 0.66; 95% CI, 0.02, 28.75; P=0.83). Overall complications were significantly reduced in the ERCP group in severe pancreatic patients (OR 0.32; 95% CI, 0.17, 0.61; P=0.00). In those with mild disease, a strong trend to decreased complications in the ERCP group was seen, however, this was not significant (OR 0.67; 95% CI, 0.43, 1.03; P=0.06).
CONCLUSIONS:

This meta-analysis demonstrates a significant decrease in complications in patients with severe GSP managed with early ERCP/ES compared with conservative management. As far as the mortality is concerned, no significant decrease was observed in mortality even in severe GSP patients treated with early ERCP/ES.

Research paper thumbnail of Rectus sheath haematoma: a rare presentation of non-contact strenuous exercises

Rectus sheath haematoma (RSH) is a well-documented but uncommon clinical condition. It is usually... more Rectus sheath haematoma (RSH) is a well-documented but
uncommon clinical condition. It is usually a self-limiting condition but can present as a life-threatening emergency. RSH after noncontact vigorous exercise is unknown. Two such cases secondary to yoga and laughter therapy sessions, respectively, are reported. One of them required surgical intervention, whereas the other was successfully treated conservatively.

Research paper thumbnail of De Garengeot hernia: an analysis of our experience.

AIM: The presence of a vermiform appendix in a femoral hernia sac is termed De Garengeot hernia.... more AIM:

The presence of a vermiform appendix in a femoral hernia sac is termed De Garengeot hernia. It may present as a tender and/or erythematous groin swelling and is often misdiagnosed as an incarcerated or strangulated femoral hernia. The purpose of this study is to review the management of De Garengeot hernia at a single institution since 1991.

MATERIALS AND METHODS:

A retrospective analysis of seven consecutive patients operated upon at our institution from 1991 to 2006 with De Garengeot hernia was undertaken. Patients' demographics, treatment performed and postoperative outcome were analysed.

RESULTS:

There were three men and four women. The median age was 55 years. None of the patients were diagnosed preoperatively. The commonest presenting symptom was painful groin swelling. All patients therefore underwent emergency surgery with a presumptive diagnosis of either incarcerated or strangulated femoral hernia. Operative findings included four normal appendices, two inflamed appendices and one perforated appendix in the femoral hernial sac. Patients with normal appendix (n = 4) had mesh hernia repair without an appendicectomy. The rest of the patients (n = 3) with abnormal appendix underwent emergency open appendicectomy followed by sutured hernia repair. We had no deaths in this series and one minor wound infection. No recurrent hernia has been detected to date.

CONCLUSION:

Inflammation of the appendix determines the type of hernia repair and surgical approach. Incidental appendicectomy in the case of a normal appendix is not preferred.