Laparoscopic Nissen fundoplication with carbon dioxide pneumoperitoneum preserves cell-mediated immunity in an immature animal model.

PURPOSE: The aim of this study is to elucidate the effects of laparoscopic Nissen fundoplication (LNF) with carbon dioxide (CO(2)) or helium (He) on the cell-mediated immune response in a pediatric animal model compared with open Nissen fundoplication (ONF). METHODS: Cell immune response was evaluated in 45 1-week-old Sprague Dawley rats using the delayed type hypersensitivity (DTH) skin test. Animals were sensitized against keyhole limpet hemocyanin (KLH) by subcutaneous injection (0.5 mg) in complete Freund's adjuvant. Animals were challenged 2 weeks later by an intradermal injection of KLH (0.3 mg) in sterile saline (challenge 1, baseline). Rats with positive DTH skin reaction at 24 and 48 hours after challenge 1 were put randomly into 4 groups (n = 10 each): I, only anesthesia (control); II, LNF with CO(2), III, LNF with He; IV, ONF. Animals were injected intradermally with KLH (0.3 mg) immediately before the procedures (challenge 2) and 3 and 6 days postoperatively (challenges 3 and 4). RESULTS: DTH skin reactions were measured 24 and 48 hours after each challenge. There were no significant changes in cell-mediated immunosuppression after LNF with CO(2). However, a transient cell-mediated immunosuppression was observed after LNF with He and ONF. All fundoplications were intact at the time of necropsy. CONCLUSIONS: These data suggest a transient suppression of cell-mediated immunity in open procedures when compared with laparoscopic interventions using CO(2) in a pediatric animal model. In addition, the type of gas used during laparoscopy also may modulate this transient immunosuppression.

Use of a cauterizing laparoscopic linear stapler in intestinal anastomosis.

The purpose of this study was to assess the usefulness of a cauterizing laparoscopic linear stapler for intestinal anastomosis. In a porcine model, intestinal anastomoses performed with a standard laparoscopic linear stapler, a cauterizing laparoscopic linear stapler (RF stapler), and a two-layer, hand-sewn technique were compared by measuring bursting pressures at 4 and 7 days after surgery. During surgery, the RF stapler provided better hemostasis than the regular stapler for mesenteric transection. At 4 days, one leak occurred in the RF stapler group, and the bursting pressure in the RF stapler group was significantly lower than the bursting pressures in the regular stapler group and the hand-sewn group. In addition, the bursting pressure was significantly greater in the hand-sewn group than in the regular stapler group at 4 days. By 7 days, there were no differences in bursting pressure among the groups. We recommend that the RF stapler not be used for intestinal anastomosis. However, the device may be beneficial for controlling vasculature.

Complications of laparoscopic treatment of esophageal achalasia in children.

BACKGROUND/PURPOSE: The aim of this study was to evaluate the incidence and management of the complications that occurred in some children who underwent laparoscopic Heller's esophagocardiomyotomy in the authors' institutions. METHODS: Between March 1993 and October 1998, the files of all the children with achalasia who underwent laparoscopic Heller's esophagocardiomyotomy in a community hospital in Naples, Italy, and a private hospital in Paris, France, were reviewed. A 5-port technique was used associating Heller's esophagocardiomyotomy to an antireflux surgical mechanism (Dor's or Toupet's) in all cases. Intra- and postoperative complications, as well as the postoperative outcome, were evaluated. RESULTS: Ten laparoscopic Heller's esophagocardiomyotomies were performed in 5 girls and 5 boys with achalasia. Age ranged between 2 and 13 years. Mean operating time was 120 minutes. Hospital stay ranged between 3 and 41 days. Complications were recorded in 3 patients: in 2 an esophageal mucosal perforation and in 1 a prolonged dysphagia. Two of these complications occurred in the last patients operated on. Follow-up varied from 6 months to 6 years. All children were free of symptoms. CONCLUSIONS: The results show that laparoscopic Heller's esophagocardiomyotomy in children is a feasible procedure. Assessment of mucosal integrity immediately after the myotomy must be performed. Complications can happen even if the operation is performed by expert laparoscopic surgeons.

Cell-mediated immune response is better preserved by laparoscopy than laparotomy.

BACKGROUND: This study compares the effects of carbon dioxide pneumoperitoneum versus laparotomy on cellular-mediated immune response in a murine model. METHODS: Sixty-eight female C3H/He mice were sensitized to keyhole limpet hemocyanin (KLH) and to a mouse mammary carcinoma cell line (MC2) before surgery. Animals were randomized into 4 groups: group I, anesthesia (control); group II, pneumoperitoneum with carbon dioxide; group III, extraperitoneal wound; group IV, laparotomy. All animals were challenged subsequently with KLH and MC2 tumor cells. Delayed-type hypersensitivity skin reaction (DTH) to KLH was measured on postoperative days (PODs) 1, 2, 4, and 5. Tumor growth was assessed weekly as an indicator of postoperative cellular immune response. RESULTS: Compared with preoperative values, postoperative DTH skin reactions were significantly less for all PODs in groups III and IV (P < .05), on POD 1 and 4 in group II (P < .05) and POD 4 for group I (P < .05). Group IV showed significantly fewer DTH skin reactions for all PODs compared with groups I and II (P < .05) and all PODs except on day 2 compared with group III (P < .05). Tumor growth was significantly increased at postoperative week 2 (n = 3/17 mice) and 3 (n = 4/17 mice) in group IV, when compared with groups I and II (P < .05). CONCLUSIONS: Cellular immunity is preserved after carbon dioxide pneumoperitoneum compared with extraperitoneal incisions and laparotomy as measured by DTH and the ability to reject an immunogenictumor.

Comparison of the stress response after laparoscopic and open cholecystectomy.

BACKGROUND: We designed a prospective controlled animal study to compare the stress response induced after laparoscopic and open cholecystectomy. METHODS: Twelve female pigs (20-25 kg body weight) were anesthetized with ketamine, pentobarbital, and fentanyl. The animals were randomized into the following four groups: control (C), pneumoperitoneum with CO(2) at 14-15 mmHg (P), laparoscopic cholecystectomy (LC), and open cholecystectomy (OC). The average duration of the procedure in each group was 35 min. RESULTS: Central venous pressure, mean arterial pressure, pulmonary capillary wedge pressure, and cardiac output were monitored. Measurements were recorded when animals were anesthetized (baseline), immediately before and after surgery, and thereafter every 30 min for a maximum of 3 h. White blood cell count (WBC) was determined from blood samples taken before and after 3 h of surgery. Ultrasound-guided liver biopsies were done preoperatively and after 3 h of surgery. Total RNA was isolated from the liver biopsy specimens. Steady-state mRNA levels of beta-fibrinogen (beta-fib), alpha 1-chymotrypsin inhibitor (alpha1-CTI), metallothionein (MT), heat shock protein 70 (Hsp70), and polyubiquitin (Ub) were detected by Northern blot/hybridization. There were no statistical differences in the hemodynamic parameters among the groups. The number of circulating neutrophils and monocytes decreased only after LC. Expression of Hsp70 was not induced after any surgical procedure, and the mRNA levels of Ub did not change after surgery. The expression of alpha1-CTI and beta-fib (acute phase genes) were similarly increased after LC and OC. Steady-state mRNA levels of MT were slightly increased after P and LC but not after OC. CONCLUSION: These data indicate that there are no significant differences between LC and OC in terms of induction of the stress response.

Long distance telementoring. A novel tool for laparoscopy aboard the USS Abraham Lincoln.

BACKGROUND: As general surgeons perform a growing number of laparoscopic operations in increasingly specialized environments, the ability to obtain expert advice during procedures becomes more important. Technological advances in video and computer communications are enabling surgeons to procure expertise quickly and efficiently. In this article, we present laparoscopic procedures completed through an intercontinental telementoring system and the first telementored laparoscopic procedures performed aboard a naval vessel. METHODS: Video, voice, and data streams were linked between the USS Abraham Lincoln Aircraft Carrier Battlegroup cruising the Pacific Ocean and locations in Maryland and California, creating the Battlegroup Telemedicine (BGTM) system. Three modes of BGTM communication were used: intraship, ship to ship, and ship to shore. RESULTS: Five laparoscopic inguinal hernia repairs were completed aboard the Lincoln under telementoring guidance from land-based surgeons thousands of miles away. In addition, the BGTM system proved invaluable in obtaining timely expertise on a wide variety of surgical and medical problems that would otherwise have required a shore visit. CONCLUSIONS: Successful intercontinental laparoscopic telementoring aboard a naval vessel was accomplished using "off-the-shelf" components. In many instances, the high risk and cost of transporting patients to land-based facilities was averted because of the BGTM system. Also, the relationship between the on-site and telementoring surgeon was critical to the success of this experiment. Long-distance telementoring is an invaluable tool in providing instantly available expertise during laparoscopic procedures.

Human vs robotic organ retraction during laparoscopic Nissen fundoplication.

BACKGROUND: Advances in technique and instrumentation have enabled surgeons to perform an increasing number of complicated procedures through laparoscopy. However, these efforts have often been compromised by the exertion of excessive force when anatomical structures are retracted to create a clear view of the anatomy. Here, we present a comparative study of human and robotic performance in force-controlled organ retraction during laparoscopic Nissen fundoplication (LNF). METHODS: Six female pigs (20-25 kg) were anesthetized, intubated, and placed on mechanical ventilation; pneumoperitoneum (13 mmHg CO2) was established. A force-sensing retractor (FSR) was constructed to record the forces applied in retracting the stomach during dissection of the esophageal hiatus. The FSR was calibrated using known forces and then operated by either human alone or robot under human guidance using the FSR data. The esophageal hiatus was visualized and dissected, and LNF was completed. RESULTS: Less force was needed for robotic (74.3 +/- 10.5 g; mean +/- standard deviation) than for human (108.9 +/- 34.3 g) retraction (p = 0.007) to obtain an optimal view of the esophageal hiatus. No significant differences were observed for retraction setup time (robot, 14.3 +/- 0.8 min; human, 13.7 +/- 9.9 min; mean +/- SD) or hiatal dissection time (robot, 14.0 +/- 3.0 min; human, 14.0 +/- 6.1 min; mean +/- SD). CONCLUSIONS: These preliminary results illustrate our continuing effort to develop and evaluate an automated surgical assistant for laparoscopy. As more personnel-intensive advanced laparoscopic procedures are performed, robotic retraction is likely to offer a superior alternative to human retraction; it minimizes the forces exerted on the organs while maintaining excellent anatomical view.

Immune response: effects of operative stress in a pediatric model.

PURPOSE: The purpose of this study is to delineate the effect of different operative procedures on the cell-mediated immune response in a pediatric animal model using the delayed type hypersensitivity (DTH) skin test. METHODS: Sprague Dawley rats (1 week old) were sensitized against keyhole limpet hemocyanin (KLH). Animals were challenged 2 weeks later by an intradermal injection of KLH (0.3 mg) in sterile saline. Rats with positive DTH skin reactions at 24 and 48 hours after challenge (baseline) were divided randomly into five groups (n = 10 each): group I, unmanipulated control; group II, anesthesia; group III, anesthesia and midline extraperitoneal incision; Group IV, anesthesia and laparoscopy (pneumoperitoneum with carbon dioxide); Group V, anesthesia and midline laparotomy. Before each procedure (day 0) and on postoperative days 3 and 6, animals were again challenged intradermally with KLH (0.3 mg). DTH skin reaction was evaluated 24 and 48 hours later. RESULTS: A statistically significant difference (P < .05) in DTH skin reaction at 24 and 48 hours was observed between postoperative days 1 to 5 in the extraperitoneal and laparotomy groups with respect to baseline and the control group. Statistically significant differences were found in postoperative days 1, 4, and 5 between laparoscopy and laparotomy. The laparoscopy group showed a statistically significant decrease in DTH skin induration on postoperative day 2 when compared with the control group. At postoperative day 7 and 8 there was no statistical difference in DTH skin response comparing baseline values or between groups. CONCLUSIONS: These results suggest that in a pediatric animal model, abdominal surgical procedures accompanied by extensive tissue dissection produce a cellular immunosuppression, lasting up to 7 days, which is not observed in less invasive procedures. Observations concerning lesser immunosuppressive effects of laparoscopy when compared with laparotomy in adult models, as previously described by our laboratory, were also found in this pediatric model.

Increased mediastinal pressure and decreased cardiac output during laparoscopic Nissen fundoplication.

BACKGROUND: Laparoscopic Nissen fundoplication (LNF) is gaining popularity. Although the hemodynamic effects of the typical pneumoperitoneum have been studied, the additional consequences of the hiatal dissection necessary for LNF have not. METHODS: Seven female pigs were anesthetized, intubated, and ventilated with a volume ventilator and hemodynamic and mechanical pressure monitoring devices were placed. Pressures were recorded every 15 minutes for 1 hour after each of four interventions: (1) anesthesia induction, (2) CO2 pneumoperitoneum (15 mm Hg), (3) LNF, and (4) release of pneumoperitoneum (and removal of ports). RESULTS: Right atrial, inferior vena caval, mediastinal, pleural, airway, and pulmonary capillary wedge pressures all increased after pneumoperitoneum (p < 0.05). Only mediastinal pressure (8.6 vs 13.7 mm Hg, pneumoperitoneum vs LNF; p < 0.05) and pleural pressure (2.6 vs 3.5 mm Hg, pneumoperitoneum vs LNF; p < 0.05) showed a further significant increase after LNF. In addition, cardiac output fell significantly after LNF (5.9 vs. 4.6 L/min; p < 0.05). Mediastinal pressure and cardiac output remained significantly altered after the release of pneumoperitoneum. CONCLUSIONS: Surgical disruption of the esophageal hiatus during LNF causes both increased mediastinal and pleural pressure and a significant reduction in cardiac output. These findings uncover a previously unsuspected physiologic detriment that may occur during LNF.