Brent D. Matthews

Comparison of ultrasonic energy, bipolar thermal energy, and vascular clips for the hemostasis of small-, medium-, and large-sized arteries

Background: Advanced laparoscopic procedures have necessitated the development of new technology for vascular control. Suture ligation can be time-consuming and cumbersome during laparoscopic dissection. Titanium clips have been used for hemostasis, and recently plastic clips and energy sources such as ultrasonic coagulating shears and bipolar thermal energy devices have become popular. The purpose of this study was to compare the bursting pressure of arteries sealed with ultrasonic coagulating shears (UCS), electrothermal bipolar vessel sealer (EBVS), titanium laparoscopic clips (LCs), and plastic laparoscopic clips (PCs). In addition, the spread of thermal injury from the UCS and the EBVS was compared. Methods: Arteries in three size groups (2–3, 4–5 and 6–7 mm) were harvested from freshly euthanized pigs. Each of the four devices was used to seal 16 specimens from each size group for burst testing. A 5-Fr catheter was placed into the open end of the specimen and secured with a purse-string suture. The catheter was connected to a pressure monitor and saline was infused until there was leakage from the sealed end. This defined the bursting pressure in mmHg. The ultrasonic shears and bipolar thermal device were used to seal an additional 8 vessels in each size group, which were sent for histologic examination. These were examined with hematoxylin and eosin stains, and the extent of thermal injury, defined by coagulation necrosis, was measured in millimeters. Analysis of variance was performed and, where appropriate, a Tukey’s test was also performed. Results: The EBVS’s mean burst pressure was statistically higher than that of the UCS at 4 or 5 mm (601 vs 205 mmHg) and 6 or 7 mm (442 vs 175 mmHg). EBVS had higher burst pressures for the 4 or 5-mm group (601 mmHg) and 6 or 7-mm group (442 mmHg) compared with its pressure at 2 or 3 mm (128 mmHg) (p = 0.0001). The burst pressures of the UCS and EBVS at 2 or 3 mm were not significantly different. Both clips were statistically stronger than the thermal devices except at 4 or 5 mm, in which case the EBVS was as strong as the LC (601 vs 593 mmHg). The PC and LC were similar except at 4 or 5 mm, where the PC was superior (854 vs 593 mmHg). The PC burst pressure for 4 or 5 mm (854 mmHg) was statistically higher than that for vessels 2 or 3 mm (737 mmHg) but not different from the 6 or 7 mm pressure (767 mmHg). Thermal spread was not statistically different when comparing EBVS and UCS at any size (EBVS mean = 2.57 mm vs UCS mean = 2.18 mm). Conclusions: Both the PC and LC secured all vessel sizes to well above physiologic levels. The EBVS can be used confidently in vessels up to 7 mm. There is no difference in the thermal spread of the LigaSure vessel sealer and the UCS.

Initial results with an electrothermal bipolar vessel sealer

BackgroundAn electrothermal bipolar vessel sealer (EBVS; Ligasure, Valleylab, Boulder, CO, USA) was developed as an alternative to suture ligatures, hemoclips, staplers, and ultrasonic coagulators for ligating vessels and tissue bundles. The EBVS seals vessels up to 7 mm in diameter by denaturing collagen and elastin within the vessel wall and surrounding connective tissue. This study is the first to determine the clinical efficacy and safety of this instrument and delineate its potential timesavings in both experimental (animal) and clinical scenarios.MethodsA prospective review of the author’s clinical experience with the EBVS in laparoscopic and open operations from October 1998 to March 2000 was performed. In addition, five Yorkshire domestic pigs underwent 150-cm small intestine resections (n=10) using the EBVS (n=5) and suture ligatures (n=5). Measurements included time to complete intestinal resection, the number of applications per minute for each method, and the presence of postapplication bleeding. Statistical analysis was performed using Student’s t-test.ResultsThe EBVS was used in 98 cases (46 laparoscopic and 52 open) with a mean of 43 applications (range, 10–150 applications) per case. The operations included 53 colon and/or small bowel resections (54.1%), 24 fundoplications (24.5%), 12 gastric resections (12.2%), 3 splenectomies, 2 pancreatectomies, 1 adrenalectomy, 1 bilateral salpingooopherectomy, 1 pancreatic cyst-jejunostomy, and 1 vagotomy with gastrojejunostomy. In all these cases, the EBVS was intended to be the only means of vessel ligation. An alternative ligation technique was required for bleeding in only 13 (0.3%) of more than 4,200 applications of the EBVS. No postoperative hemorrhagic complications occurred. There was an estimated mean reduction in operative time of 39 min per open procedure, and a mean prolongation in operative time of 8 min per laparoscopic procedure when the EBVS was used in lieu of suture ligatures, hemoclips, staplers, or ultrasonic coagulators. In the animal model, the mean time for completion of the intestinal resection was 251.9 s for the EBVS and 702.0 s for ligatures (p<0.001). The mean number of applications per minute was 7.6 for the EBVS and 1.8 for ligatures (p<0.001). No postapplication bleeding was seen.ConclusionsInitial clinical results from the use of EBVS in laparoscopic and open procedures demonstrate it to be safe and effective, reducing operative time in open procedures. Suture ligatures, ties, hemoclips, and other ligating techniques were used rarely (0.3%) after an application of the EBVS. In an experimental animal model, the EBVS was significantly faster and more efficient (more applications per minute) than ligatures for intestinal resection.

Laparoscopic vs open resection of gastric stromal tumors.

BackgroundGastric stromal tumors are rare neoplasms that may be benign or malignant. Given that malignant gastric stromal tumors rarely involve lymph nodes and require excision with negative margins, they appear amendable to laparoscopic excision. There are few reports of laparoscopic resection, and no comparisons have been done between laparoscopic and open surgery. This study compares the relative efficacy of the two approaches.MethodsBetween May 1994 and December 2000, 33 patients underwent 35 operations for gastric stromal tumors. Laparoscopic resections were performed in 21 patients; open resections were done in 12 patients. The medical records of the patients were reviewed retrospectively with regard to operating time, blood loss, length of stay, and clinical course.ResultsPatient demographics, tumor characteristics (mean tumor size, benign vs malignant), and presenting symptoms were similar for both groups. In the laparoscopic group, 15 wedge resections; three partial gastrectomies, and three transgastric needlescopic enucleations were performed. In the open group, six vedge resections, four antrectomies, and two partial proximal gastrectomies were performed. There were no significant differences in mean operative time (169 vs 160 min), mean estimated blood loss (106 vs 129 cc), or perioperative complication rate (9.5% vs 8.3%) between the laparoscopic and open groups, respectively. The mean length of stay was significantly less (p<0.05) in the laparoscopic group (3.8 vs 6.2 days). Average follow-up was 1.5 years. One patient in each group has died due to metastastic disease. There have been no trocar site recurrences.ConclusionsLaparoscopic resection of gastric stromal tumors is safe and appropriate. Tumor size, operating time, and estimated blood loss were equivalent to the open approach, and there was a statistically shorter hospital stay in the laparoscopic group.

Pooled Data Analysis of Laparoscopic vs. Open Ventral Hernia Repair: 14 Years of Patient Data Accrual

BackgroundThe purpose of this study was to analyze the published perioperative results and outcomes of laparoscopic (LVHR) and open (OVHR) ventral hernia repair focusing on complications and hernia recurrences.MethodsData were compiled from all English-language reports of LVHR published from 1996 through January 2006. Series with fewer than 20 cases of LVHR, insufficient details of complications, or those part of a larger series were excluded. Data were derived from 31 reports of LVHR alone (unpaired studies) and 14 that directly compared LVHR to OVHR (paired sudies). Chi-squared analysis, Fisher’s exact test, and two-tailed t-test analysis were used.ResultsForty-five published series were included, representing 5340 patients (4582 LVHR, 758 OVHR). In the pooled analysis (combined paired and unpaired studies), LVHR was associated with significantly fewer wound complications (3.8% vs. 16.8%, p < 0.0001), total complications (22.7% vs. 41.7%, p < 0.0001), hernia recurrences (4.3% vs. 12.1%, p < 0.0001), and a shorter length of stay (2.4 vs. 4.3 days, p = 0.0004). These outcomes maintained statistical significance when only the paired studies were analyzed. In the pooled analysis, LVHR was associated with fewer gastrointestinal (2.6% vs. 5.9%, p < 0.0001), pulmonary (0.6% vs. 1.7%, p = 0.0013), and miscellaneous (0.7% vs. 1.9%, p = 0.0011) complications, but a higher incidence of prolonged procedure site pain (1.96% vs. 0.92%, p = 0.0469); none of these outcomes was significant in the paired study analysis. No differences in cardiac, neurologic, septic, genitourinary, or thromboembolic complications were found. The mortality rate was 0.13% with LVHR and 0.26% with OVHR (p = NS). Trends toward larger hernia defects and larger mesh sizes were observed for LVHR.ConclusionsThe published literature indicates fewer wound-related and overall complications and a lower rate of hernia recurrence for LVHR compared to OVHR. Further controlled trials are necessary to substantiate these findings and to assess the health care economic impact of this approach.

Assessment of Adhesion Formation to Intra-Abdominal Polypropylene Mesh and Polytetrafluoroethylene Mesh

BACKGROUND The development of intra-abdominal adhesions, bowel obstruction, and enterocutaneous fistulas are potentially severe complications related to the intraperitoneal placement of prosthetic biomaterials. The purpose of this study was to determine the natural history of adhesion formation to polypropylene mesh and two types of polytetrafluoroethylene (ePTFE) mesh when placed intraperitoneally in a rabbit model that simulates laparoscopic ventral hernia repair. MATERIALS AND METHODS Thirty New Zealand white rabbits were used for this study. A 10-cm midline incision was performed for intra-abdominal access and a 2 cm x 2 cm piece of mesh (n = 60) was sewn to an intact peritoneum on each side of the midline. Two types of ePTFE mesh (Dual Mesh and modified Dual Mesh, W.L. Gore & Assoc., Flagstaff, AZ) and polypropylene mesh were compared. The rate of adhesion formation was evaluated by direct visualization using microlaparoscopy (2-mm endoscope/trocar) at 7 days, 3 weeks, 9 weeks, and 16 weeks after mesh implantation. Adhesions to the prosthetic mesh were scored for extent (%) using the Modified Diamond Scale (0 = 0%, 1 <or= 25%, 2 = 25-50%, 3 > 50%). At necropsy the mesh was excised en bloc with the anterior abdominal wall for histological evaluation of mesothelial layer growth. RESULTS The mean adhesion score for the polypropylene mesh was significantly greater (P < 0.05) than Dual Mesh at 9 weeks and 16 weeks and modified Dual Mesh at 7 days, 9 weeks, and 16 weeks. Fifty-five percent (n = 11) of the polypropylene mesh had adhesions to small intestine or omentum at necropsy compared to 30% (n = 6) of the Dual Mesh and 20% (n = 4) of the modified Dual Mesh. There was a significantly greater percentage (P < 0.003) of ePTFE mesh mesothelialized at explant (modified Dual Mesh 44.2%; Dual Mesh 55.8%) compared to the polypropylene mesh (12.9%). CONCLUSIONS Serial microlaparoscopic evaluation of intraperitoneally implanted polypropylene mesh and ePTFE mesh in a rabbit model revealed a progression of adhesions to polypropylene mesh over a 16 week period. The pore size of mesh is critical in the development and maintenance of abdominal adhesions and tissue ingrowth. The macroporous polypropylene mesh promoted adhesion formation, while the microporous nature of the visceral side of the ePTFE served as a barrier to adhesions.

Initial results with a stapled gastrojejunostomy for the laparoscopic isolated Roux-en-Y gastric bypass

BACKGROUND The gastric pouch to jejunum anastomosis is a critical step in the performance of an isolated Roux-en-Y gastric bypass. When performing this procedure laparoscopically, intracorporeal suturing of the gastric pouch to Roux-en-Y jejunum anastomosis is technically demanding, time consuming, and perhaps the most prohibitive part of the operation. We devised a unique, effective, and simple method to perform this anastomosis using an EEA stapler. This report describes this technique and its follow-up in our series of patients undergoing a laparoscopic isolated Roux-en-Y gastric bypass utilizing this technique. METHODS A prospective analysis was performed identifying the technical success, leak rate, and postoperative incidence of anastomotic stenosis and its management in a consecutive series of patients undergoing a laparoscopic isolated Roux-en-Y gastric bypass with a gastrojejunal anastomosis constructed with a 21-mm or 25-mm EEA stapler. RESULTS Forty-eight patients underwent laparoscopic isolated Roux-en-Y gastric bypass. Mean age was 40.9 years (range 22 to 64) and mean body mass index was 52.3 kg/m(2) (range 31 to 76 kg/m(2)). There were no mortalities. Three patients (6.3%) were converted to an open procedure, but only 1 because of an inability to perform the gastrojejunal anastomosis (short jejunal mesentery). There was 1 leak (2.1%) from the gastrojejunal anastomosis. It was successfully managed nonoperatively. Thirteen patients (27.1%) patients developed an anastomotic stenosis requiring endoscopic balloon dilatation. Seven of the 13 patients required only a single dilatation and have had no recurrence of dysphagia. Six of the 13 patients needed 2 to 4 dilatations, and all are swallowing normally. None have required surgical revision. After 12 months of follow-up, the mean weight loss was 115 pounds and mean decrease in body mass index was 18.5 kg/m(2). CONCLUSIONS The stapled EEA gastrojejunal anastomosis for the laparoscopic isolated Roux-en-Y gastric bypass is safe and effective. Anastomotic stenosis occurs in approximately one quarter of patients, but it can be managed well with endoscopic balloon dilatation.

Histologic and Biomechanical Evaluation of Crosslinked and Non-Crosslinked Biologic Meshes in a Porcine Model of Ventral Incisional Hernia Repair

BACKGROUND The objective of this study was to evaluate the biomechanical characteristics and histologic remodeling of crosslinked (Peri-Guard, Permacol) and non-crosslinked (AlloDerm, Veritas) biologic meshes over a 12 month period using a porcine model of incisional hernia repair. STUDY DESIGN Bilateral incisional hernias were created in 48 Yucatan minipigs and repaired after 21 days using an underlay technique. Samples were harvested at 1, 6, and 12 months and analyzed for biomechanical and histologic properties. The same biomechanical tests were conducted with de novo (time 0) meshes as well as samples of native abdominal wall. Statistical significance (p < 0.05) was determined using 1-way analysis of variance with a Fishers least significant difference post-test. RESULTS All repair sites demonstrated similar tensile strengths at 1, 6, and 12 months and no significant differences were observed between mesh materials (p > 0.05 in all cases). The strength of the native porcine abdominal wall was not augmented by the presence of the mesh at any of the time points, regardless of de novo tensile strength of the mesh. Histologically, non-crosslinked materials showed earlier cell infiltration (p < 0.01), extracellular matrix deposition (p < 0.02), scaffold degradation (p < 0.05), and neovascularization (p < 0.02) compared with crosslinked materials. However, by 12 months, crosslinked materials showed similar results compared with the non-crosslinked materials for many of the features evaluated. CONCLUSIONS The tensile strengths of sites repaired with biologic mesh were not impacted by very high de novo tensile strength/stiffness or mesh-specific variables such as crosslinking. Although crosslinking distinguishes biologic meshes in the short-term for histologic features, such as cellular infiltration and neovascularization, many differences diminish during longer periods of time. Characteristics other than crosslinking, such as tissue type and processing conditions, are likely responsible for these differences.

Laparoscopic Curative Resection of Pheochromocytomas

Purpose:Pheochromocytomas are relatively uncommon tumors whose operative resection has clear medical and technical challenges. While the safety and efficacy of laparoscopic adrenalectomy are relatively well documented, few studies with extended follow-up have been conducted to measure the success of the procedure for the most challenging of the adrenal tumors. In addition, several reports question the applicability of a minimally invasive approach for sizeable pheochromocytomas. The purpose of our investigation was to assess the outcomes of laparoscopic adrenalectomy for pheochromocytomas in the largest study to date when performed by experienced laparoscopic surgeons. Methods:All pheochromocytomas removed by the authors from January 1995 to October 2004 were reviewed under an Institutional Review Board approved protocol. Eighty-five percent were documented in a prospective fashion. Results:Eighty consecutive patients underwent laparoscopic resection of 81 pheochromocytomas. Seventy-nine were found in the adrenal (42 left, 35 right, 1 bilateral); 2 were extra-adrenal paragangliomas. Eight patients had multiple endocrine neoplasia syndrome. Two lesions were malignant. There were 48 females and 32 males with a mean age of 45 years (range, 15–79 years). Mean tumor size was 5.0 cm (range, 2–12.1 cm); 41 of these lesions were 5 cm in size or larger. Average operative time and blood loss were 169 minutes (range, 69–375 minutes) and 97 mL (range, 20–500 mL), respectively. Intraoperative hypertension (systolic blood pressure, >170 mm Hg) was reported in 53% of patients and hypotension (systolic blood pressure, <90 mm Hg) in 28% of patients. There were no conversions to open surgery. Mean length of stay was 2.3 days (range, 1–10 days). There were 6 perioperative morbidities (7.5%) and no mortalities. No patient required a blood transfusion. No recurrence of endocrinopathy has been documented at a mean follow-up of 21.4 months. Conclusion:Laparoscopic resection of pheochromocytomas, including large lesions, can be accomplished safely by experienced surgeons. A short hospital stay with minimal operative morbidity and eradication of endocrinopathy support the minimally invasive approach for adrenalectomy in the setting of pheochromocytoma.

A Comparison of Laparoscopic Bipolar Vessel Sealing Devices in the Hemostasis of Small-, Medium-, and Large-Sized Arteries

INTRODUCTION The development of new energy sources for hemostasis has facilitated advanced laparoscopic procedures. Few studies, however, have documented the strength of the vessels sealed or the extent of surrounding lateral thermal injury, two important factors in maintaining hemostasis while preventing injury to surrounding structures. This study compared the burst pressure and extent of thermal injury of vessels sealed with the 5-mm laparoscopic PlasmaKinetics trade mark sealer (PK) (Gyrus Medical, Maple Grove, Minnesota) and the 5-mm laparoscopic LigaSure trade mark sealing device (LS) (Valleylab, Boulder, Colorado). METHODS Arteries in three sizes (2-3 mm, 4-5 mm, and 6-7 mm) were harvested from domestic pigs. Eight to 17 specimens from each size were randomly sealed with the PK, and the same number with the LS. Burst pressures were measured in mm Hg. The extent of thermal injury, determined by coagulation necrosis, was measured microscopically in millimeters after staining the transected vessels with hematoxylin and eosin. Descriptive statistics, including means and standard deviations, are reported. Students t-test and ANOVA were performed to determine significance (P <.05). RESULTS The mean bursting pressures of the PK and the LS were equal in the 2-3 mm vessels (397 vs. 326 mm Hg, P =.49). The PK bursting pressures were significantly less than the LS in the 4-5 mm (389 vs. 573 mm Hg, P =.02) and the 6-7 mm groups (317 vs. 585 mm Hg, P =.0004). As vessel size increased, the PK was associated with significantly lower burst pressures, while the LS was associated with progressively higher burst pressures (P =.035). Thermal spread was not significantly different between the PK and the LS in the 2-3 mm (1.5 vs. 1.2 mm, P =.27), the 4-5 mm (2.4 vs. 2.4 mm, P =.79), or the 6-7 mm vessel size groups (3.2 vs. 2.5 mm, P =.32). Increasing vessel size, regardless of instrument used, was associated with increased thermal injury (P <.0001). CONCLUSION The LS produces supraphysiologic seals with significantly higher bursting pressures than the PK in vessels ranging from 4 to 7 mm. The PK seals become progressively weaker while the LS seals increase in strength as the vessel size increases. Although thermal spread increases with vessel size, the degree of lateral thermal injury is no different between the two instruments.

Outcomes analysis of laparoscopic resection of pancreatic neoplasms

BackgroundExperience with laparoscopic resection of pancreatic neoplasms remains limited. The purpose of this study is to critically analyze the indications for and outcomes after laparoscopic resection of pancreatic neoplasms.MethodsThe medical records of all patients undergoing laparoscopic resection of pancreatic neoplasms from July 2000 to February 2006 were reviewed. Data are expressed as mean ± standard deviation.ResultsLaparoscopic pancreatic resection was performed in 22 patients (M:F, 8:14) with a mean age of 56.3 ± 15.1 years and mean body mass index (BMI) of 26.3 ± 4.5 kg/m2. Nine patients had undergone previous intra-abdominal surgery. Indications for pancreatic resection were cyst (1), glucagonoma (1), gastrinoma (2), insulinoma (3), metastatic tumor (2), IPMT (4), nonfunctioning neuroendocrine tumor (3), and mucinous/serous cystadenoma (6). Mean tumor size was 2.4 ± 1.6 cm. Laparoscopic distal pancreatectomy was attempted in 18 patients and completed in 17, and enucleation was performed in 4 patients. Laparoscopic ultrasound (n = 10) and a hand-assisted technique (n = 4) were utilized selectively. Mean operative time was 236 ± 60 min and mean blood loss was 244 ± 516 ml. There was one conversion to an open procedure because of bleeding from the splenic vein. The mean postoperative LOS was 4.5 ± 2.0 days. Seven patients experienced a total of ten postoperative complications, including a urinary tract infection (UTI) (1), lower-extremity deep venous thrombosis (DVT) and pulmonary embolus (1), infected peripancreatic fluid collection (1), pancreatic pseudocyst (1), and pancreatic fistula (6). Five pancreatic fistulas were managed by percutaneous drainage. The reoperation rate was 4.5% and the overall pancreatic-related complication rate was 36.4%. One patient developed pancreatitis and a pseudocyst 5 months postoperatively, which was managed successfully with a pancreatic duct stent. There was no 30-day mortality.ConclusionsLaparoscopic pancreatic resection is safe and feasible in selected patients with pancreatic neoplasms. With a pancreatic duct leak rate of 27%, this problem remains an area of development for the minimally invasive technique.