Paul D Hansen

Cost-effective management of common bile duct stones: a decision analysis of the use of endoscopic retrograde cholangiopancreatography (ERCP), intraoperative cholangiography, and laparoscopic bile duct exploration.

BackgroundThere are a variety of approaches to the diagnosis and treatment of common bile duct (CBD) stones in patients undergoing laparoscopic cholecystectomy (LC).MethodsDecision modeling was used to evaluate the cost-effectiveness of four strategies for managing CBD stones around the time of LC: (a) routine preoperative endoscopic retrograde cholangiopancreatography (ERCP) (preoperative ERCP), (b) LC with intraoperative cholangiography (IOC), followed by laparoscopic common bile duct exploration (LCDE), (c) LC with IOC, followed by ERCP (postoperative ERCP), and (d) expectant management (LC without any tests for CBD stones). Local hospital data were used to estimate costs. Cost-effectiveness was expressed in terms of the cost per case of residual CBD stones prevented (in excess of the cost of LC alone). Diagnostic test characteristics, procedure success rates, and adverse event probabilities were derived from a systematic review of the literature. Sensitivity analysis was used to explore the effect of uncertainty on the results of the model.ResultsLC alone was the least costly strategy, but it was also the least effective. Of the more aggressive strategies, LCDE and preoperative ERCP were associated with marginal costs of

Outcomes of laparoscopic herniorrhaphy without fixation of mesh to the abdominal wall

5993.60 and

A decision analysis of the optimal initial approach to achalasia: Laparoscopic heller myotomy with partial fundoplication, thoracoscopic heller myotomy, pneumatic dilatation, or botulinum toxin injection

299,259.35, respectively, per case of residual CBD stones prevented. Postoperative ERCP was more costly and less effective than LCDE, but it had a lower cost-effectiveness ratio than preoperative ERCP when the prevalence of CBD stones was <80%.ConclusionsCompared to other common approaches, laparoscopic CBD exploration is a cost-effective method of managing CBD stones in patients who undergo LC. If expertise in LCDE is unavailable, selective postoperative ERCP is preferred over routine preoperative ERCP, unless the probability of CBD stones is very high (>80%).

Preoperative determinants of an esophageal lengthening procedure in laparoscopic antireflux surgery

Background: Recently there has been interest in performing laparoscopic herniorrhaphies without the use of staples or tacks to fix the mesh. Although mesh fixation has been linked to an increased incidence of nerve injury and involves increased operative costs, many surgeons feel that fixation is necessary to reduce the risk of hernia recurrence. This study evaluates the outcomes of laparoscopic herniorrhapies performed with and without mesh fixation at our institution. Methods: We retrospectively evaluated our last 172 laparoscopic herniorrhaphies, which span a period of conversion from staple fixation to nonfixation of total extraperitoneal herniorrhaphies using systematic chart review and follow-up self-administered questionnaires. The outcomes assessed were the incidences of postoperative neuralgia and hernia recurrence. Adjustment for important prognostic factors was achieved using Cox regression for estimating the risk of recurrence, and multiple logistic regression for estimating the risk of neuropathic complications. Results: Of 172 laparoscopic herniorrhaphies performed in 129 patients since July 1993, 105 were accomplished without mesh fixation, and 67 were performed with fixation of mesh to the abdominal wall. There were no significant differences in demographics between the two groups. A trend toward a higher incidence of neuropathic complications was observed in the mesh-fixation group (risk ratio [RR], 2.2; 95% CI, 0.5-10). A nonsignificant increased risk of hernia recurrence with fixation of mesh was observed (4.2 vs 1.6 per 100 hernia-years at risk; RR, 2.3; 95% CI, 0.4-13.10), but this finding may be associated with a selection bias with regard to giant hernia defects. Conclusions: Our data suggest that mesh fixation to the abdominal wall may be avoided in total extraperitoneal repairs without increasing the risk of hernia recurrence and neuropathic complications. The increased risk of recurrence observed with mesh fixation possibly results from selection bias. Large randomized controlled studies are needed to determine whether mesh fixation is truly related to neuropathic complications and the incidence of recurrence.

A mathematical model for preoperative planning of radiofrequency ablation of hepatic tumors

In the absence of randomized controlled trials that directly compare all of the modern methods of managing achalasia, decision analysis may help determine the optimal treatment strategy. Four strategies for the initial management of achalasia were compared using the following decision model: (1) laparoscopic Heller myotomy and partial fundoplication; (2) pneumatic dilatation; (3) botulinum toxin injection; and (4) thoracoscopic Heller myotomy. Probabilities of clinical events and utilities of health states were estimated using review of the medical literature and patient interviews. A recursive decision tree (Markov model) was used to simulate all the important outcomes of each initial treatment option, allowing for complications, relapses over time, and transitions between strategies when appropriate. After 10 years, laparoscopic Heller myotomy with partial fundoplication was associated with the longest quality-adjusted survival (quality-adjusted life years [QALY] = 7.41). The difference between this strategy and either pneumatic dilatation or botulinum toxin injection was small. Thoracoscopic Heller myotomy was associated with the poorest quality-adjusted survival (QALY = 7.15). Pneumatic dilatation was the favored strategy when the effectiveness of laparoscopic surgery at relieving dysphagia was less than 89.7%, the operative mortality risk was greater than 0.7%, or the probability of reflux after pneumatic dilatation was less than 19%. In a decision model, laparoscopic Heller myotomy with partial fundoplication is at least as effective as endoscopic approaches for managing achalasia symptoms. However, the differences are small enough that patient preferences and local expertise should be taken into consideration when tailoring a treatment plan for an individual patient.

Laparoscopic placement of hepatic artery infusion pumps: technical considerations and early results.

BACKGROUND In a minority of patients undergoing antireflux surgery, an esophageal lengthening procedure is required to reduce the gastroesophageal junction (GEJ) below the esophageal hiatus. We evaluated risk factors associated with an irreducible GEJ to identify clinical features that were predictive of the need for a Collis gastroplasty in patients undergoing laparoscopic antireflux surgery. METHODS Patients who required a Collis gastroplasty during a laparoscopic antireflux procedure (defined as the inability to reduce the GEJ > 2.5 cm below the esophageal hiatus despite extensive mobilization of the mediastinal esophagus) were compared to a random sample of patients who did not have a Collis gastroplasty. Predictors of the need for an esophageal lengthening procedure were identified using logistic regression modeling. Risks were expressed as odds ratios (OR) and 95% confidence intervals (CI). RESULTS Twenty patients who had a Collis gastroplasty were compared to 133 patients who had adequate esophageal length. The presence of a stricture (OR 3.0; 95% CI 1.0, 9.7), paraesophageal hernia (OR 3.5; 95% CI 1.3, 9.6), Barretts esophagus (OR 3.7, 95% CI 1.3, 10.7), and re-do antireflux surgery (OR 6.4; 95% CI 2.0, 20.7) were associated with the need for gastroplasty. Patients with none of these factors were extremely unlikely to require a gastroplasty (OR 0.08; 95% CI 0.02, 0.34). CONCLUSION Patients undergoing laparoscopic antireflux surgery who are at high risk of needing an esophageal lengthening procedure can be easily identified preoperatively using simple clinical characteristics.

Laparoscopic radiofrequency ablation and hepatic artery infusion pump placement in the evolving treatment of colorectal hepatic metastases

Background: Radiofrequency ablation (RFA) is rapidly evolving as an effective minimally invasive technique for the treatment of small and unresectable liver tumors. A potential cause of treatment failure is the inability to determine the optimum number of overlapping ablations needed to completely destroy tumors larger than the size of a single ablation. To clarify this relationship, we performed a mathematical evaluation that enables us to accurately estimate the number of ablations needed to completely ablate larger tumors. Methods: This estimation is based on the assumptions that complete ablation of the surface of a target tumor, including its blood supply, would completely destroy the tumor and that the tumor and ablations produced are perfectly spherical. The smallest possible number of partially overlapping ablations that would completely cover the surface of the target tumor is the same as the number of faces on a regular polyhedron that has a circumscribing diameter equal to or greater than the diameter of the target sphere. Results: This mathematical analysis shows that for a 5-cm ablation device, tumors with diameters ranging between 3.01 and 3.30 cm will require at least four ablations. Tumors between 3.31 and 4.12 cm require six overlapping ablations, and tumors between 4.13 and 6.23 cm require 12 overlapping ablations. The number of ablations needed for larger tumors and for 3-, 4-, 6-, and 7-cm ablation devices are also determined. Conclusion: The smallest number of ablations required to completely ablate a spherical target tumor larger than the size of the ablation sphere increases dramatically as tumor size increases. Because this model is geometrically optimized, even a small change in the position of the ablation spheres with respect to the target sphere can leave potentially unablated tumor and thus result in treatment failure.

Transthoracic hepatic radiofrequency ablation

BackgroundLaparoscopic hepatic artery infusion pump (LHAIP) placement is a novel treatment option for patients with colorectal liver metastases. This study investigates technical difficulties with regard to variant hepatic arteries and the preliminary outcomes for patients treated with LHAIP placement.MethodsBetween March 1998 and January 2003, 38 patients with colorectal metastases confined to the liver, 35 (92%) of who had prior systemic chemotherapy that failed, were treated with LHAIP.ResultsTwelve patients (32%) had LHAIP placement only, and 26 (68%) had pump placement combined with laparoscopic radiofrequency ablation (LRFA; 24 patients) and/or liver resection (2 patients). Variant hepatic arterial (HA) anatomy was present in 18 patients (47%). The presence of a variant HA did not increase pump complications, operative time, or blood loss (P ≥ .20) or decrease the functional time of pump use (P = .91) in comparison with normal anatomy. In all patients with a variant HA, laparoscopic ligation of the variant vessel and/or cannulation of nongastroduodenal artery resulted in complete hepatic perfusion. Three misperfusions identified intraoperatively with use of methylene blue injection were corrected by laparoscopic ligation (two) or postoperative angioembolization (one). Postoperative pump radionuclide flow studies confirmed isolated hepatic artery infusion in all cases. There was a 13% pump-related complication rate. During a median follow-up of 11 months (0.5 to 35.5 months), the actuarial rate of overall survival was 47% and the estimated median survival time was 17.5 months.ConclusionsLHAIP placement is technically feasible, and variant HA is not associated with increased pump complications or decreased pump functional time.

Incidence of cancer of the pancreas, extrahepatic bile duct and ampulla of Vater in the United States, before and after the introduction of laparoscopic cholecystectomy

Background: Laparoscopic radiofrequency ablation (LRFA) and laparoscopic hepatic artery infusion pump (LHAIP) placement are new treatment options for patients with colorectal liver metastases. This study investigates the selection criteria, safety, efficacy, and preliminary outcomes of patients treated with LRFA and LHAIP placement. Methods: Fourty five patients with colorectal metastases confined to the liver, 37 of whom had failed systemic chemotherapy, were treated with LRFA and/or LHAIP between September 1996 and December 2001. Treatment selection was individualized, based on each patients general health, liver function, and tumor size, number, location, and distribution. Results: Twenty patients (44%) had LRFA alone, 10 (22%) had LHAIP placement alone, and 15 (33%) patients had combined LRFA and LHAIP therapy. The LRFA group had a significantly shorter mean operative time and blood loss (p <0.05), but hospital stays were similar when compared to patients receiving LRFA + LHAIP or LHAIP alone. Tumor characteristics were worse in both LHAIP groups, with a higher incidence of tumors ?4 cm, major vascular involvement, diffuse tumor pattern, bilobar distribution, and involvement of more than three segments. During a mean follow-up period of 11.5 ± 7.8 months (range, 1–38), the actuarial survival was 70%, 67%, and 50% for LRFA, LRFA + LHAIP, and LHAIP, respectively. LHAIP only patients had the shortest estimated mean survival time of the three groups by Kaplan-Meier survival curves (p = 0.001). Conclusion: LRFA and/or LHAIP placement are safe and feasible treatment options for the treatment of colorectal hepatic metastases. The choice of treatment for patients should be based primarily on tumor characteristics. Long-term studies, which will elucidate the role of these evolving treatments, are now under way.

Laparoscopic resections of liver and pancreas

Background:Radiofrequency ablation (RFA) is an alternative for the treatment of unresectable hepatic tumors. Tumors beneath the diaphragmatic dome may be difficult to access by laparoscopy. In these cases, a transthoracic transdiaphragmatic approach for delivering RFA can be used.Methods:Three patients with hepatic metastatic disease were treated using a transthoracic transdiaphragmatic approach to deliver RFA therapy for tumors in liver segments 7 and 8. The patients underwent thoracoscopy. The tumors were identified using transdiaphragmatic ultrasound, and transthoracic transdiaphragmatic RFA (TTRFA) was performed.Results:In three patients, TTRFA was successfully used to ablate five lesions. There were no perioperative complications, blood loss was minimal,and postoperative hospital stays ranged from 2 to 8 days. There were no recurrences during a follow-up period of 4 to 20 months.Conclusions:TTRFA is a viable alternative for hepatic tumors located beneath the dome of the diaphragm that are difficult to access by laparoscopy.