Ahmad H. M. Nassar
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Ahmad H. M. Nassar has a total of 18 co-authors. Here are the top co-authors by number of shared publications:
- Ahmed Hamouda
Guy’s and St Thomas’ NHS Foundation Trust, UK
3 shared publications Zubir Ahmed
Monklands Hospital
2 shared publicationsA. Mughrabi
Monklands Hospital
1 shared publicationB. Mohammed
Monklands Hospital, Lanarkshire, Scotland, United Kingdom
1 shared publicationC. Seow
Monklands Hospital
1 shared publicationC. Sharp
Monklands Hospital
1 shared publication
Latest Publications
- 12 May 2012
- Published by Springer Nature in Surgical Endoscopy
- Vol. 26 (11) , 3190-3194
Intrahepatic choledochoscopy during trans-cystic common bile duct exploration; technique, feasibility and value
Transcystic laparoscopic common bile duct exploration (TC-LCBDE) is advantageous for exploring the bile duct. Choledochoscopy, however, may be quite challenging to perform transcystically because the cystic duct is usually narrow, duct anatomy may be unfavorable, and not all stones are amenable to transcystic extraction. Convention suggests that it is technically very difficult to visualize the intrahepatic bile ducts with transcystic choledochoscopy, due to the angle of insertion of the cystic into the common bile duct (CBD). However, we have performed intrahepatic choledochoscopy successfully, moving the choledochoscope from the CBD into the common hepatic duct by using what we have termed a “wiper blade maneuver”. The purpose of this study was to confirm how often this was possible. A search of a prospectively collected database of patients undergoing routine intraoperative cholangiography (IOC) and laparoscopic CBD exploration under the care of a single consultant surgeon was performed. A total of 592 LCBDEs were performed between September 1992 and January 2011; 325 were transcystic explorations. Of these, 72.5 % were female and 56 % were admitted acutely. Exploration and duct clearance was performed by blind Dormia basket trawling in 63 %. The choledochoscope was utilized in 120 cases (37 %). The 3-mm choledochoscope was used in 66 (55 %) and the 5-mm scope in 54 (45 %). Intrahepatic choledochoscopy was performed in 49 patients (40.8 %). Length of surgery was 40–350 min (median 90 min; standard deviation 49 min). It is technically challenging to perform intrahepatic choledochoscopy with a 3-mm choledochoscope due to its narrow gauge. The more rigid 5-mm scope is thus preferred, but is limited in TCE because its effective use depends on the presence of a dilated cystic duct. Despite the technical limitations of both caliber scopes, we have demonstrated that intrahepatic choledochoscopy during TCE is possible, with each, in 40 % of cases.
- 12 May 2012
- Published by Springer Nature in Surgical Endoscopy
- Vol. 26 (11) , 3190-3194
Intrahepatic choledochoscopy during trans-cystic common bile duct exploration; technique, feasibility and value
Transcystic laparoscopic common bile duct exploration (TC-LCBDE) is advantageous for exploring the bile duct. Choledochoscopy, however, may be quite challenging to perform transcystically because the cystic duct is usually narrow, duct anatomy may be unfavorable, and not all stones are amenable to transcystic extraction. Convention suggests that it is technically very difficult to visualize the intrahepatic bile ducts with transcystic choledochoscopy, due to the angle of insertion of the cystic into the common bile duct (CBD). However, we have performed intrahepatic choledochoscopy successfully, moving the choledochoscope from the CBD into the common hepatic duct by using what we have termed a “wiper blade maneuver”. The purpose of this study was to confirm how often this was possible. A search of a prospectively collected database of patients undergoing routine intraoperative cholangiography (IOC) and laparoscopic CBD exploration under the care of a single consultant surgeon was performed. A total of 592 LCBDEs were performed between September 1992 and January 2011; 325 were transcystic explorations. Of these, 72.5 % were female and 56 % were admitted acutely. Exploration and duct clearance was performed by blind Dormia basket trawling in 63 %. The choledochoscope was utilized in 120 cases (37 %). The 3-mm choledochoscope was used in 66 (55 %) and the 5-mm scope in 54 (45 %). Intrahepatic choledochoscopy was performed in 49 patients (40.8 %). Length of surgery was 40–350 min (median 90 min; standard deviation 49 min). It is technically challenging to perform intrahepatic choledochoscopy with a 3-mm choledochoscope due to its narrow gauge. The more rigid 5-mm scope is thus preferred, but is limited in TCE because its effective use depends on the presence of a dilated cystic duct. Despite the technical limitations of both caliber scopes, we have demonstrated that intrahepatic choledochoscopy during TCE is possible, with each, in 40 % of cases.
- 1 January 2010
- Published by Springer Nature in Surgical Endoscopy
- Vol. 24 (7) , 1552-1556
Laparoscopic transcystic bile duct exploration: the treatment of first choice for common bile duct stones
This study was designed to explore the role of transcystic bile duct exploration (TCE) as a first line of treatment for patients with suspected or incidental common bile duct (CBD) stones. A prospective, case-control study of clinically comparable groups of patients who underwent laparoscopic cholecystectomy (LC) alone (n = 1,854) and combined LC/TCE for CBD stones (n = 253) under the care of one surgeon was performed. Other than ultrasonography, no routine preoperative imaging was used; however, we performed routine intraoperative cholangiography on all patients. There was no difference in age (49 ± 15 vs. 57 ± 19, p = 0.7), sex (79% vs. 82% females, p = 0.6), and ASA grade (1.9 ± 1 vs. 1.8 ± 1, p = 0.7). A larger proportion of the TCE group presented as an emergency (TCE 45% vs. LC alone 27%, p = 0.03) and more often presented with acute biliary pain compared with LC alone (27% vs. 13%, p = 0.02). Although a majority of the patients in the TCE group had clinical or biochemical risk factors for CBD stones (86%), only 27% had suspected stones on preoperative ultrasound. The incidence of jaundice (6% vs. 20%, p = 0.01) was lower in the LC alone group compared with TCE patients. Previous abdominal surgery was noted in 34% patients who underwent LC alone and 30% in LC/TCE (p = 0.06). Significantly there was no difference in open conversion between the two groups (LC alone 0.5% vs. LC/TCE 0.6%, p = 0.07). Comparison of selected outcome parameters for LC versus TCE showed a postoperative hospital stay of 2 (1–14) vs. 2 (1–17) days (p = 0.07), presentation to resolution 1 (1–11) vs. 1 (1–11) weeks (p = 0.07), and morbidity 1.07% vs. 1.2% (p = 0.07). The study advocates single-session laparoscopic cholecystectomy with transcystic CBD exploration as a feasible first choice treatment and the logical next step in the management of patients with CBD stones.
- 1 January 2010
- Published by Springer Nature in Surgical Endoscopy
- Vol. 24 (7) , 1552-1556
Laparoscopic transcystic bile duct exploration: the treatment of first choice for common bile duct stones
This study was designed to explore the role of transcystic bile duct exploration (TCE) as a first line of treatment for patients with suspected or incidental common bile duct (CBD) stones. A prospective, case-control study of clinically comparable groups of patients who underwent laparoscopic cholecystectomy (LC) alone (n = 1,854) and combined LC/TCE for CBD stones (n = 253) under the care of one surgeon was performed. Other than ultrasonography, no routine preoperative imaging was used; however, we performed routine intraoperative cholangiography on all patients. There was no difference in age (49 ± 15 vs. 57 ± 19, p = 0.7), sex (79% vs. 82% females, p = 0.6), and ASA grade (1.9 ± 1 vs. 1.8 ± 1, p = 0.7). A larger proportion of the TCE group presented as an emergency (TCE 45% vs. LC alone 27%, p = 0.03) and more often presented with acute biliary pain compared with LC alone (27% vs. 13%, p = 0.02). Although a majority of the patients in the TCE group had clinical or biochemical risk factors for CBD stones (86%), only 27% had suspected stones on preoperative ultrasound. The incidence of jaundice (6% vs. 20%, p = 0.01) was lower in the LC alone group compared with TCE patients. Previous abdominal surgery was noted in 34% patients who underwent LC alone and 30% in LC/TCE (p = 0.06). Significantly there was no difference in open conversion between the two groups (LC alone 0.5% vs. LC/TCE 0.6%, p = 0.07). Comparison of selected outcome parameters for LC versus TCE showed a postoperative hospital stay of 2 (1–14) vs. 2 (1–17) days (p = 0.07), presentation to resolution 1 (1–11) vs. 1 (1–11) weeks (p = 0.07), and morbidity 1.07% vs. 1.2% (p = 0.07). The study advocates single-session laparoscopic cholecystectomy with transcystic CBD exploration as a feasible first choice treatment and the logical next step in the management of patients with CBD stones.
- 16 February 2007
- Published by Springer Nature in Surgical Endoscopy
- Vol. 21 (9) , 1671-1673
A new endoscopic technique for the buried bumper syndrome
The Buried Bumper Syndrome is a well-recognized long-term complication of percutaneous endoscopic gastrostomy (PEG). Overgrowth of gastric mucosa over the inner bumper of the tube will cause mechanical failure of feed delivery, rendering the tube useless. Endoscopic removal is usually attempted but fails in most cases. Therefore, most of the buried inner bumpers are removed by making an external incision over the PEG site under local anaesthesia or at laparotomy. These approaches can be associated with pain, wound infection, or a gastrocutaneous fistula. A new method to facilitate the removal of a PEG tube, where the inner bumper is buried in the gastric mucosa, is described. A length of ureteric catheter, or similar tube, is passed through the shortened external PEG tube into the gastric cavity and is then tied to the tube above the skin. The intragastric part of that tube helps to identify the site of the buried bumper and is then trapped within an endoscopic snare. Traction is then applied to the snare, inverting the tube and dislodging the bumper with minimum disruption to the stomach wall. This avoids the need for repair and allows for immediate reinsertion of a fresh PEG tube. A PEG tube in a patient with buried bumper syndrome can be safely removed endoscopically, without a skin incision or gastric wall disruption. A novel, simple, and safe endoscopic removal technique is described.
- 16 February 2007
- Published by Springer Nature in Surgical Endoscopy
- Vol. 21 (9) , 1671-1673
A new endoscopic technique for the buried bumper syndrome
The Buried Bumper Syndrome is a well-recognized long-term complication of percutaneous endoscopic gastrostomy (PEG). Overgrowth of gastric mucosa over the inner bumper of the tube will cause mechanical failure of feed delivery, rendering the tube useless. Endoscopic removal is usually attempted but fails in most cases. Therefore, most of the buried inner bumpers are removed by making an external incision over the PEG site under local anaesthesia or at laparotomy. These approaches can be associated with pain, wound infection, or a gastrocutaneous fistula. A new method to facilitate the removal of a PEG tube, where the inner bumper is buried in the gastric mucosa, is described. A length of ureteric catheter, or similar tube, is passed through the shortened external PEG tube into the gastric cavity and is then tied to the tube above the skin. The intragastric part of that tube helps to identify the site of the buried bumper and is then trapped within an endoscopic snare. Traction is then applied to the snare, inverting the tube and dislodging the bumper with minimum disruption to the stomach wall. This avoids the need for repair and allows for immediate reinsertion of a fresh PEG tube. A PEG tube in a patient with buried bumper syndrome can be safely removed endoscopically, without a skin incision or gastric wall disruption. A novel, simple, and safe endoscopic removal technique is described.
- 7 February 2007
- Published by Springer Nature in Surgical Endoscopy
- Vol. 21 (6) , 955-959
Intraoperative cholangiography facilitates simple transcystic clearance of ductal stones in units without expertise for laparoscopic bile duct surgery
In the absence of facilities and expertise for laparoscopic bile duct exploration (LBDE), most patients with suspected ductal calculi undergo preoperative endoscopic duct clearance. Intraoperative cholangiography (IOC) is not performed at the subsequent laparoscopic cholecystectomy. This study aimed to investigate the rate of successful duct clearance after simple transcystic manipulations. This prospective study investigated 1,408 patients over 13 years in a unit practicing single-session management of biliary calculi. For the great majority, IOC was attempted. Abnormalities were dealt with by flushing of the duct, glucagon injection, Dormia basket trawling, choledochoscopic transcystic exploration, or choledochotomy. Of 1,056 cholangiograms performed (75%), 287 were abnormal (27.2%). Surgical trainees, operating under supervision, successfully performed 24% of all cholangiograms. Of 396 patients admitted with biliary emergencies, 94.1% had abnormal cholangiograms. Of the 287 patients with abnormal IOCs, 9.4% required no intervention, 18% were clear after glucagon and flushing, and 13% were cleared using Dormia basket trawling under fluoroscopy. A total of 95 patients required formal LBDE, and 2 required postoperative endoscopic retrograde cholangiopancreatography (ERCP). No postoperative ERCP for retained stones was required after simple transcystic manipulation. Eight conversions occurred, one during a transcystic exploration. Follow-up evaluation continued for as long as 6 years in some cases. Two patients had recurrent stones after LBDE and a clear postoperative tube cholangiogram. In this series, 10% of the abnormal cholangiograms occurred in patients without preoperative risk factors for bile duct stones. Altogether, 88 IOCs (31%) were cleared after either simple flushing or trawling with a Dormia basket. Formal LBDE was not required for 40% of abnormal cholangiograms. Simple transcystic manipulations to clear the bile ducts justify the use of routine IOC in units without laparoscopic biliary expertise.
- 7 February 2007
- Published by Springer Nature in Surgical Endoscopy
- Vol. 21 (6) , 955-959
Intraoperative cholangiography facilitates simple transcystic clearance of ductal stones in units without expertise for laparoscopic bile duct surgery
In the absence of facilities and expertise for laparoscopic bile duct exploration (LBDE), most patients with suspected ductal calculi undergo preoperative endoscopic duct clearance. Intraoperative cholangiography (IOC) is not performed at the subsequent laparoscopic cholecystectomy. This study aimed to investigate the rate of successful duct clearance after simple transcystic manipulations. This prospective study investigated 1,408 patients over 13 years in a unit practicing single-session management of biliary calculi. For the great majority, IOC was attempted. Abnormalities were dealt with by flushing of the duct, glucagon injection, Dormia basket trawling, choledochoscopic transcystic exploration, or choledochotomy. Of 1,056 cholangiograms performed (75%), 287 were abnormal (27.2%). Surgical trainees, operating under supervision, successfully performed 24% of all cholangiograms. Of 396 patients admitted with biliary emergencies, 94.1% had abnormal cholangiograms. Of the 287 patients with abnormal IOCs, 9.4% required no intervention, 18% were clear after glucagon and flushing, and 13% were cleared using Dormia basket trawling under fluoroscopy. A total of 95 patients required formal LBDE, and 2 required postoperative endoscopic retrograde cholangiopancreatography (ERCP). No postoperative ERCP for retained stones was required after simple transcystic manipulation. Eight conversions occurred, one during a transcystic exploration. Follow-up evaluation continued for as long as 6 years in some cases. Two patients had recurrent stones after LBDE and a clear postoperative tube cholangiogram. In this series, 10% of the abnormal cholangiograms occurred in patients without preoperative risk factors for bile duct stones. Altogether, 88 IOCs (31%) were cleared after either simple flushing or trawling with a Dormia basket. Formal LBDE was not required for 40% of abnormal cholangiograms. Simple transcystic manipulations to clear the bile ducts justify the use of routine IOC in units without laparoscopic biliary expertise.
- 28 July 2005
- Published by Springer Nature in Surgical Endoscopy
- Vol. 19 (10) , 1370-1372
Intraoperative cholangiography time in laparoscopic cholecystectomy
The debate for and against the routine use of intraoperative cholangiography (IOC) continues. One of the main arguments against the routine use of the technique during laparoscopic cholecystectomy (LC) is the length of time it takes, which in turn increases the cost. In this study, we recorded the time spent by the radiographer providing IOC service in the context of optimizing the utilization of the radiographer and IOC time. A total of 91 consecutive LCS, including 19 laparoscopic bile duct explorations, from April 2003 to January 2004 were included in the study. We recorded the time the radiographer took from receiving a call to arriving in the theater, the time he or she spent performing the IOC, and the total time spent in theater. We also recorded the total operative time. The mean time from call to arrival was 9 min (SD = 3, n = 91). The mean total time spent by the radiographer in the theater involved in performing the IOC during LC was 15 min (SD = 8, n = 72), and that during laparoscopic exploration was 46 min (SD = 20, n = 19). The mean operative time was 67 min (SD = 24) and 135 min (SD = 59), respectively. Radiographer services as well as IOC time could be optimized to facilitate the routine use of this important technique in LC. Optimizing the logistics and time factor in IOC is an integral component of single-stage management of patients with suspected bile duct stones.
- 28 July 2005
- Published by Springer Nature in Surgical Endoscopy
- Vol. 19 (10) , 1370-1372
Intraoperative cholangiography time in laparoscopic cholecystectomy
The debate for and against the routine use of intraoperative cholangiography (IOC) continues. One of the main arguments against the routine use of the technique during laparoscopic cholecystectomy (LC) is the length of time it takes, which in turn increases the cost. In this study, we recorded the time spent by the radiographer providing IOC service in the context of optimizing the utilization of the radiographer and IOC time. A total of 91 consecutive LCS, including 19 laparoscopic bile duct explorations, from April 2003 to January 2004 were included in the study. We recorded the time the radiographer took from receiving a call to arriving in the theater, the time he or she spent performing the IOC, and the total time spent in theater. We also recorded the total operative time. The mean time from call to arrival was 9 min (SD = 3, n = 91). The mean total time spent by the radiographer in the theater involved in performing the IOC during LC was 15 min (SD = 8, n = 72), and that during laparoscopic exploration was 46 min (SD = 20, n = 19). The mean operative time was 67 min (SD = 24) and 135 min (SD = 59), respectively. Radiographer services as well as IOC time could be optimized to facilitate the routine use of this important technique in LC. Optimizing the logistics and time factor in IOC is an integral component of single-stage management of patients with suspected bile duct stones.
- 1 January 2005
- Published by Taylor & Francis in Minimally Invasive Therapy & Allied Technologies
- Vol. 14 (6) , 369-371
Voice recognition interfaces (VRI) optimize the utilization of theatre staff and time during laparoscopic cholecystectomy
During laparoscopy, members of staff spend time setting up and de‐activating the light source, camera and insufflator. Voice Recognition Interface (VRI) devices, such as HERMES (Stryker Europe, Montreux, Switzerland), enable the surgeon to perform and control these and other functions. They recognize the surgeon's voice and adjust the instruments in response to programmed verbal commands. The aim of this study was to evaluate HERMES with regards to the utilization of time and theatre staff during laparoscopic cholecystectomy. A total of 100 patients were randomized to either HERMES‐assisted or standard laparoscopic cholecystectomy. Three time variables were measured for performing three VRI tasks: (1) The initial setting up of the light source and camera, (2) the activation of the insufflator, and (3) the deactivation of the insufflator and light source at the end of the operation. The mean (and standard deviation) of the time in seconds required for setting up the light source and camera was 27.6 (26.9) in non‐HERMES operations and 11.7 (4.7) in HERMES‐assisted cases (p<0.001). Insufflation time was 19.8 (13.3) vs. 6.7 (2.5) (p<0.001), and switch‐off time was 19.5 (11.8) vs. 11.8 (5.7) (p<0.001). HERMES optimized the operating time and the utilization of theatre staff during laparoscopic cholecystectomy.
- 1 January 2005
- Published by Taylor & Francis in Minimally Invasive Therapy & Allied Technologies
- Vol. 14 (6) , 369-371
Voice recognition interfaces (VRI) optimize the utilization of theatre staff and time during laparoscopic cholecystectomy
During laparoscopy, members of staff spend time setting up and de‐activating the light source, camera and insufflator. Voice Recognition Interface (VRI) devices, such as HERMES (Stryker Europe, Montreux, Switzerland), enable the surgeon to perform and control these and other functions. They recognize the surgeon's voice and adjust the instruments in response to programmed verbal commands. The aim of this study was to evaluate HERMES with regards to the utilization of time and theatre staff during laparoscopic cholecystectomy. A total of 100 patients were randomized to either HERMES‐assisted or standard laparoscopic cholecystectomy. Three time variables were measured for performing three VRI tasks: (1) The initial setting up of the light source and camera, (2) the activation of the insufflator, and (3) the deactivation of the insufflator and light source at the end of the operation. The mean (and standard deviation) of the time in seconds required for setting up the light source and camera was 27.6 (26.9) in non‐HERMES operations and 11.7 (4.7) in HERMES‐assisted cases (p<0.001). Insufflation time was 19.8 (13.3) vs. 6.7 (2.5) (p<0.001), and switch‐off time was 19.5 (11.8) vs. 11.8 (5.7) (p<0.001). HERMES optimized the operating time and the utilization of theatre staff during laparoscopic cholecystectomy.