An evaluation of electrosurgical vessel-sealing devices in biliary tract surgery in a porcine model.

OBJECTIVES: The purpose of this study was to evaluate two electrosurgical vessel-sealing devices in biliary surgery. METHODS: Porcine common bile ducts (CBDs) were sealed with two electrosurgical devices, an electrothermal bipolar vessel-sealing device (EBVS) and ultrasonic coagulation shears. Acute study animals underwent surgical bile duct sealing followed by immediate burst pressure testing. Chronic study animals were maintained for 1 week postoperatively and then tested. RESULTS: The seal failure rate in the acute study was 50% for both the EBVS device and shears, and 0% for the laparoscopic surgical clip device used as a control. The latter had significantly higher burst pressures (646.2 ± 281.8 mmHg; P = 0.006) than the EBVS device (97.6 ± 86.6 mmHg) and shears (71.7 ± 89.3 mmHg). No significant difference in burst pressures was noted between the EBVS device and shears (97.6 ± 86.6 mmHg vs. 71.7 ± 89.3 mmHg). In the chronic study, obvious bile leaks occurred in one of four pigs (25%) in the EBVS device subgroup and two of four pigs (50%) in the shears subgroup. The average proximal CBD pressure in seven pigs was 16.1 ± 4.1 mmHg. The average chronic burst pressure in the control subgroup was 1088.0 ± 922.6 mmHg. CONCLUSIONS: Given the high rates of failure of the EBVS device and the shears in consistently sealing biliary ducts, we do not recommend their routine use in biliary surgery.

Pushing the envelope in biomaterial research: initial results of prosthetic coating with stem cells in a rat model.

BACKGROUND: Coating prosthetic for hernia repair with a patient's own cells could improve biocompatibility by decreasing inflammation and adhesion formation and by increasing tissue ingrowth and resistance to infection. The objective of this study was to prove the feasibility of prosthetic coating with stem cells and to assess its resistance to adhesion formation when implanted in an animal model. METHODS: Adult Lewis rat bone marrow stem cells were harvested and cultured. Stem cells were then implanted on three different prosthetics. The prosthetic with the best stem cell adherence was implanted intraperitoneally into six adult rats. Untreated prosthetic was implanted in control animals (n = 12). After 2 weeks, intra-abdominal adhesions were graded using an adhesion scoring scale by two surgeons who were blinded to the animal group. Data were analyzed using the Wilcoxon rank-sum test. RESULTS: Stem cells demonstrated the best adherence and growth on polyglactin prosthetics. After implantation, the stem cell-coated polyglactin prosthetic had <25% of its surface area covered with adhesions in five (83%) samples, whereas the control polyglactin group had only one sample (8.3%) with <25% adhesions, and seven of its samples (58.3%) had >50% surface area adhesions (p < 0.05). CONCLUSIONS: The feasibility of hernia prosthetic coating with stem cells was demonstrated. Furthermore, stem-cell coated polyglactin prosthetic exhibited improved biocompatibility by decreasing adhesion formation in an animal model. Further study is needed to determine the factors that promote stem cell adherence to prosthetics and the in vivo prosthetic biomechanics after stem cell coating. This work is underway in our laboratory.

Short-term outcomes after unilateral versus complete thyroidectomy for malignancy: a national perspective.

The extent of thyroidectomy for well-differentiated thyroid cancer (WDTC) remains controversial. We compared outcomes of patients undergoing unilateral thyroid lobectomy (UTL) versus complete thyroidectomy (CT) to determine the best operative management of WDTC. We compared outcomes of patients who underwent UTL or CT for malignancy using the 1999 to 2003 editions of the National Inpatient Sample database. A total of 13,854 patients underwent UTL (n = 4,238) and CT (n = 9,616). The CT group was more likely to have complications than the UTL group (15% vs 6%, P < 0.0001). Mean total charges were higher in the CT group ($11,432) versus the UTL group ($9,739), as was LOS (2 days versus 1 day); P < 0.0001. Complete thyroidectomy is associated with increased morbidity, total charges, and length of stay. The higher risk of short-term complications should be considered when considering performing a complete thyroidectomy for WDTC.

A comparison of gastrojejunal anastomoses with or without buttressing in a porcine model.

INTRODUCTION: The addition of staple-line reinforcements on circular anastomoses has not been well studied. We histologically and mechanically analyzed circular- stapled anastomoses with and without bioabsorbable staple-line reinforcement (SeamGuard, W. L. Gore & Associates, Flagstaff, AZ) in a porcine model. METHODS: Gastrojejunal anastomoses were constructed using a #25 EEA Proximate ILS (Ethicon Endo-Surgery, Cincinnati, OH) mechanical stapling device with and without Bioabsorbable SeamGuard (BSG). Gastrojejunal anastomoses were resected acutely and at 1 week, and burst-pressure testing and histological analysis were performed. Standardized grading systems for inflammation, collagen deposition, vascularity, and serosal inflammation were used to compare the two anastomosis types. RESULTS: Acute burst pressures were significantly higher with BSG than with staples alone (1.37 versus 0.39 psi, p=0.0075). Burst pressures at 1 week were significantly lower with BSG than with staples alone (2.24 versus 3.86 psi, p=0.0353); however, both readings were above normal physiologic intestinal pressures. There was no statistical difference in inflammation (13.4 versus 15.6, p=0.073), width of mucosa (3.2 mm versus 3.2 mm, p=0.974), adhesion formation (0 versus 0.5, p=0.575), number of blood vessels (0.5 versus 1.0, p=0.056), or serosal inflammation (2.0 versus 1.0, p=0.27) between the stapled anastomoses and those buttressed with BSG. Stapled-only anastomoses had statistically more collagen (2.0 versus 1.0, p=0.005) than the anastomoses supported with BSG. CONCLUSIONS: The addition of BSG as a staple-line reinforcement acutely improves the burst strength of a circular anastomosis but not at 1 week. At 1 week, a decrease in collagen content with the BSG-buttressed stapled anastomosis was the only difference in the histologic parameters studied with no difference in vascularity, adhesions, or inflammation. The long-term effect of BSG on anastomotic strength or scarring is yet to be determined. The clinical implications may include decreased stricture formation and also decreased strength at anastomoses.

Comparison of blood vessel sealing among new electrosurgical and ultrasonic devices.

BACKGROUND: Bipolar electrosurgical devices and ultrasonic devices are routinely used in open and advanced laparoscopic surgery for hemostasis. New electrosurgical and ultrasonic instruments demonstrate improved quality and efficiency in blood vessel sealing. METHODS: The 5-mm laparoscopic Gyrus PKS Cutting Forceps (PK), Gyrus Plasma Trissector (GP), Harmonic Scalpel (HS), EnSeal Tissue Sealing and Hemostasis System (RX), LigaSure V with LigaSure Vessel Sealing Generator (LS), LigaSure V with Force Triad Generator (FT), and Ligamax 5 Endoscopic Multiple Clip Applier (LM) were tested to compare burst pressure, sealing time, and failure rate. Each device was used to seal 13 small (2-3 mm diameter), 13 medium (4-5 mm diameter), and 13 large (6-7 mm diameter) arteries from euthanized pigs. A p value <0.05 was considered statistically significant. RESULTS: Mean burst pressures were not statistically different for 2-3 mm or 6-7 mm vessels. For 4-5 mm vessels, LS had the highest mean burst pressure recorded. Mean seal times were shorter for every vessel size when FT was compared with LS (p < 0.05). The shortest sealing times for 2-3 mm vessels were recorded for GP. The shortest sealing times for medium and large vessels were observed with FT. The highest percentage failure rate for each vessel size occurred with GP. For 4-5 mm diameter vessels, the failure rate was 48% for GP, 41% for PK, and 22% for HS. For 6-7 mm diameter vessels, the failure rate was 92% for GP, 41% for PK, and 8% for HS. LM and FT had no recorded failures. CONCLUSION: Among the new 5-mm laparoscopic electrosurgical and ultrasonic instruments available for testing, RX, LS, and FT produced the highest mean burst pressures. FT had the shortest mean seal times for medium and large vessels. Minimal or no seal failures occurred with HS, RX, LS, LM, and FT.

Guidelines for power and time variables for microwave ablation in an in vivo porcine kidney.

PURPOSE: Microwave technology provides an emerging thermal ablation technique for solid organ tumors. We propose guidelines and recommend optimal time and power for use. METHODS: Microwave ablations using a VivaWave Microwave Ablation System (Valleylab, Boulder, CO) were performed in vivo in a porcine kidney model. The independent variables were power (20, 30, 40, 45, 50, 60 W) and time (2, 4, 6, 8, 10, 15, 20 min) with the outcome variable diameter of ablation. Following ablations, kidneys were procured for gross and histological evaluation. Analysis of variance (ANOVA) was used followed by Tukey tests when appropriate. A P value of <0.05 was considered statistically significant. RESULTS: In 308 total ablations, a minimum of 7 ablations were performed in 35 of 42 power and time variables (83%). The outcome variable, ablation diameter, was affected significantly by time, power, and time/power interaction (P < 0.0001). For each time point, a one-way ANOVA showed an overall significant difference in ablation size X wattage (P < 0.0001). Tukey tests showed that, at each time point, ablation sizes at 45, 50, and 60 W were not significantly different. After determining that 45 W was optimal, a one-way ANOVA showed an overall significant difference in ablation sizes for time points at 45 W (P < 0.0001). Tukey tests showed that, at 45 W, ablation sizes at 10 min were significantly larger than ablation sizes at 8, 6, 4, and 2 min. CONCLUSIONS: We propose guidelines for use of a novel microwave ablation system and recommend use at 45 W for 10 min.

Safety and efficacy of the electrothermal bipolar vessel sealer in trauma.

The electrothermal bipolar vessel sealer (EBVS) was developed as an alternative to sutures, clips, and the ultrasonic scalpel for haemostasis during open and laparoscopic surgery. The purpose of this prospective clinical study was to objectively evaluate the performance of the EBVS during trauma surgery. Data from trauma cases, in which the EBVS was used, was collected prospectively for 19 consecutive months. Data collected included: total number of EBVS applications, need for additional haemostatic devices after application, calculated time savings or loss, and hemorrhagic complications. The EBVS was used in 23 trauma cases consisting of 13 small bowel resections, 4 ileocolectomies, 2 left hemicolectomies, 1 transverse colectomy, 1 right hemicolectomy with roux-en-Y gastrojejunostomy and duodenostomy, 1 Hartmann's procedure, and 1 splenorrhaphy with omental injury repair. A total of 631 applications of the device were used, averaging 27.4 applications per case. An additional suture ligature or clip placed for an inadequate EBVS seal (failure) was needed in only 1.5% of the total EBVS applications. All of these (10) occurred in one patient undergoing Hartmann's procedure for massive colonic injury. An additional 45 sutures or clips for non-EBVS failure were used in 5 cases due to proximity of bleeding to critical vascular, biliary, or bowel structures. In 17 trauma cases (74%) with intestinal resection no other means of hemostasis (sutures or clips) was required except the EBVS. The mean calculated time savings using the EBVS was 26.8 min (range 9.8-48) per case. There were no haemorrhagic complications. The EBVS is safe and effective for intestinal resections and haemostasis in trauma surgery. This novel energy source reliably seals major mesenteric vessels with little need for sutures or clips. Using the EBVS can substantially shorten operative time.

Comparing quality-of-life outcomes in symptomatic patients undergoing laparoscopic or open ventral hernia repair.

BACKGROUND: The aim of this study was to compare quality-of-life outcomes in patients with symptomatic hernias who were undergoing laparoscopic and open repairs. MATERIALS AND METHODS: Clinical data for patients undergoing ventral hernia repair were reviewed with quality-of-life surveys administered before and at least 6 months following surgery. RESULTS: The study included 56 symptomatic patients. Forty-one patients (73%) underwent laparoscopic repair, and 15 patients (27%) underwent open repair. There was no difference in preoperative quality-of-life scores on the SF-36 Health Survey between patients having laparoscopic or open repairs. Postoperative quality-of-life scores on the SF-36 survey were significantly improved in the laparoscopic group, compared with the open group, in general health (46% vs. 37%; P=0.0217), vitality (53% vs. 45%; P=0.0491), role-emotional (45% vs. 35%; P=0.0480), and mental health (49% vs. 39%; P=0.0381). Postoperative quality-of-life scores on the Carolinas Comfort Scale (CCS) were significantly improved in the laparoscopic group, compared with the open group, in bending over (3.15 vs. 5.87, P=0.0158), sitting up (2.51 vs. 5.13; P=0.0211), activities of daily living (2.48 vs. 5.75; P=0.0139), coughing or deep breathing (2.95 vs. 5.75; P=0.0314), walking (2.36 vs. 4.62; P=0.0427), exercising (3.19 vs. 6.14; P=0.0222), and total comfort scale (17.62 vs. 40.23; P=0.0084). CONCLUSIONS: Laparoscopic ventral hernia repair provides improved quality-of-life, compared with open repair, 6 months postoperatively. Nearly all physical variables measured by the CCS were significantly better when ventral hernias were repaired laparoscopically.

Development of a functional, internet-accessible department of surgery outcomes database.

The need for surgical outcomes data is increasing due to pressure from insurance companies, patients, and the need for surgeons to keep their own "report card". Current data management systems are limited by inability to stratify outcomes based on patients, surgeons, and differences in surgical technique. Surgeons along with research and informatics personnel from an academic, hospital-based Department of Surgery and a state university's Department of Information Technology formed a partnership to develop a dynamic, internet-based, clinical data warehouse. A five-component model was used: data dictionary development, web application creation, participating center education and management, statistics applications, and data interpretation. A data dictionary was developed from a list of data elements to address needs of research, quality assurance, industry, and centers of excellence. A user-friendly web interface was developed with menu-driven check boxes, multiple electronic data entry points, direct downloads from hospital billing information, and web-based patient portals. Data were collected on a Health Insurance Portability and Accountability Act-compliant server with a secure firewall. Protected health information was de-identified. Data management strategies included automated auditing, on-site training, a trouble-shooting hotline, and Institutional Review Board oversight. Real-time, daily, monthly, and quarterly data reports were generated. Fifty-eight publications and 109 abstracts have been generated from the database during its development and implementation. Seven national academic departments now use the database to track patient outcomes. The development of a robust surgical outcomes database requires a combination of clinical, informatics, and research expertise. Benefits of surgeon involvement in outcomes research include: tracking individual performance, patient safety, surgical research, legal defense, and the ability to provide accurate information to patient and payers.

Optimal treatment of hepatic abscess.

Many treatment strategies have been proposed for pyogenic liver abscesses; however, the indications for liver resection for treatment have not been studied in a systematic manner. The purpose of our study was to evaluate the role of surgical treatment in pyogenic abscesses and to determine an optimal treatment algorithm. We retrospectively reviewed the medical records of all patients who had a pyogenic liver abscess at Rhode Island Hospital between 1995 and 2002. Abscesses and treatment strategies were classified into three groups each. The abscess groups included Abscess Type I (small <3 cm), Abscess Type II (large >3 cm, unilocular), and Abscess Type III (large >3 cm, complex multilocular). The treatment strategy groups included Treatment Group A (antibiotics alone), Treatment Group B (percutaneous drainage plus antibiotics), and Treatment Group C (primary surgical therapy). Descriptive statistics were calculated and chi2 used for comparison with a P < 0.05 considered significant. Our study consisted of 107 patients with pyogenic liver abscess. The success rate for small abscesses treated with antibiotics was 100 per cent. The success rate with antibiotics and percutaneous drainage for large, unilocular abscesses was 83 per cent and for large, multiloculated abscesses was 33 per cent. None of the 27 patients who had surgical therapy for large, multiloculated abscesses had recurrences. Surgical treatment for large (>3 cm), multiloculated abscesses had a significantly higher success rate than percutaneous drainage plus antibiotic therapy (33% versus 100%, P < or = 0.01). The mortality rate for the percutaneous drainage plus antibiotic group was not significantly different from the primary surgical group (4.2% versus 7.4%, P = 0.40). We propose a treatment algorithm with small abscesses being treated with antibiotics alone; large, uniloculated abscess with percutaneous drainage plus antibiotics; and large, multiloculated abscessed treated with surgical therapy.

Guidelines for power and time variables for microwave ablation in a porcine liver.

The purpose of our study was to provide guidelines for the use of a novel microwave ablation system. Microwave ablations using a 915-MHz system were evaluated in a porcine liver. The independent variables were power and time, with the outcome variable being diameter of ablation. After ablations, livers were procured for measurement and histologic evaluation. Our study consisted of 420 ablations. The outcome variable, ablation diameter, was affected significantly by time, power, and time/power interaction (p<0.0001). For each time point, a one-way analysis of variance (ANOVA) showed an overall significant difference in ablation size X wattage (p<0.0001). Tukey tests at each time point showed ablation sizes at 45, 50, and 60 W were not significantly different. After it was determined that 45 W was optimal, a one-way ANOVA showed an overall significant difference in ablation sizes for time points at 45 W (p<0.0001). Tukey tests revealed that at 45 W, ablation sizes at 10, 15, and 20 min were not statistically different. We propose guidelines for diameters based on different time and power variables and recommend 45 W for 10 min to achieve optimal diameters at the shortest time and lowest wattage.

Postoperative pulmonary embolism: timing, diagnosis, treatment, and outcomes.

BACKGROUND: Postoperative pulmonary embolism (PE) remains a major health concern. The purpose of our study was to evaluate our experience with postoperative PE. METHODS: We retrospectively reviewed the medical records of patients who had a postoperative PE at our institution. RESULTS: Our study included 115 patients. Prophylaxis was administered preoperatively in 31% of patients and postoperatively in 56% of patients. The diagnosis was obtained by computed tomography scan in 74 patients (64%), ventilation-perfusion scan in 24 patients (21%), angiogram in 8 patients (7%), and other modalities in 9 patients (8%). The time elapsed between surgery and the diagnosis of PE varied significantly by patient age (<40 y: 3 d, compared with 40-60 y: 11 d; P = .02). The majority of patients with PE were treated with anticoagulation (83%). Morbidity and mortality rates both were 9%. CONCLUSIONS: Age has a significant impact on the timing of postoperative PE, with the majority of cases being diagnosed with a computed tomography scan, and treated with anticoagulation.

Reversal of Hartmann's procedure: a high-risk operation?

BACKGROUND: Patients who undergo Hartmann's procedure often do not have their colostomy closed based on the perceived risk of the operation. This study evaluated the outcome of reversal of Hartmann's procedure based on preoperative risk factors. METHODS: We retrospectively reviewed adult patients who underwent reversal of Hartmann's procedure at our tertiary referral institution. Patient outcomes were compared based on identified risk factors (age >60 years, American Society of Anesthesiologists [ASA] score >2, and >2 preoperative comorbidities). RESULTS: One-hundred thirteen patients were included. Forty-four patients (39%) had an ASA score of >or=3. The mean hospital duration of stay was 6.8 days. There were 28 (25%) postoperative complications and no mortality. Patients >60 years old had significantly longer LOS compared with the rest of the group (P = .02). There were no differences in outcomes between groups based on ASA score or the presence of multiple preoperative comorbidities. An albumin level of <3.5 was the only significant predictor of postoperative complications (P = .04). CONCLUSIONS: The reversal of Hartmann's operation appears to be a safe operation with acceptable morbidity rates and can be considered in patients, including those with significant operative risk factors.

Hepatic tumor ablation with clustered microwave antennae: the US Phase II trial.

BACKGROUND: Thermal ablation techniques have become important treatment options for patients with unresectable hepatic malignancies. Microwave ablation (MWA) is a new thermal ablative technique that uses electromagnetic energy to produce coagulation necrosis. We report outcomes from the first clinical trial in the United States using MWA and a 915 MHz generator. PATIENTS AND METHODS: Patients with unresectable primary or metastatic liver cancer were enrolled in a multi-institutional trial from March 2004 through May 2006. Demographic information, diagnosis, treatment, and outcomes were documented. RESULTS: Eighty-seven patients underwent 94 ablation procedures for 224 hepatic tumors. Forty-two ablations (45%) were performed open, 7 (7%) laparoscopically, and 45 (48%) percutaneously. The average tumor size was 3.6 cm (range 0.5-9.0 cm). Single antenna ablation volumes were 10.0 ml (range 7.8-14.0 ml), and clustered antennae ablation volumes were 50.5 ml (range 21.1-146.5 ml). Outcome variables were measured with a mean follow-up of 19 months. Local recurrence at the ablation site occurred in 6 (2.7%) tumors, and regional recurrence occurred in 37 (43%) patients. With a mean follow-up of 19 months, 41 (47%) patients were alive with no evidence of disease. There were no procedure-related deaths. The overall mortality rate was 2.3%. CONCLUSIONS: Microwave ablation is a safe and effective technology for hepatic tumor ablation. In our study, clustered antennae resulted in larger ablation volumes. Further studies with histological confirmation are needed to verify clinical results.

Abdominal wall reconstruction after temporary abdominal closure: A ten-year review.

Abdominal wall reconstruction (AWR) is often required for hernias created after temporary abdominal closure (TAC). Demographic and clinical data from patients undergoing TAC and AWR between January 1, 1992, and December 31, 2002, were collected and univariate analysis performed. Temporary abdominal closure and AWR were performed in 21 patients. Complications developed in 12 patients (57.1%) after TAC; associated risk factors were mesh placement (P = .04) and skin grafting (P = .04). Successful AWR included mesh (n = 6), component separation (n = 6), primary repair (n = 4), and 3 combination techniques. Six patients (28.6%) developed intraoperative complications, and 14 (66.7%) developed postoperative complications. Intraoperative complications were increased in patients with tissue expanders (P = .01). Postoperative complications (P = .04) were less likely with component separation. The complication rate with TAC and AWR is high. Tissue expanders are associated with an increased risk of intraoperative complications with AWR, whereas component separation is associated with a reduction in postoperative complications.