Peritoneal macrophage and blood monocyte functions after open and laparoscopic-assisted cecectomy in rats.

BACKGROUND: It has been well established that open abdominal surgery results in systemic immunosuppression postoperatively; in contrast, laparoscopic surgery is associated with significantly better preserved systemic immune function. However, when intraperitoneal (local) immune function is considered, laparoscopic procedures done under a CO2 pneumoperitoneum (pneumo) have been shown to result in greater immunosuppression compared to that of open surgery. Few studies have simultaneously assessed systemic and local immune function. The purpose of this study was to assess peripheral blood mononuclear cell (PBMC) and peritoneal macrophage tumor necrosis factor-alpha (TNF-alpha) levels, H2O2 production, and MHC class II antigen expression after open and laparoscopically assisted cecectomy in a rat model. METHODS: A total of 75 Sprague Dawley rats were used for three separate experiments. For each study, rats were randomly divided into three groups: anesthesia alone (AC), laparoscopic-assisted cecectomy (LC), and open cecectomy via full laparotomy (OP). A CO2 pneumo was used for laparoscopic operations. On postoperative day 1 the animals were sacrificed, macrophages were harvested via intraperitoneal lavage, and PBMCs were isolated from whole blood obtained by cardiac puncture. In experiment 1, macrophages and PBMC from each animal were stimulated with lipopolysaccharide, after which TNF-alpha levels of the supernatant were determined. In experiment 2, after stimulation with PMA, H2O2 release was assessed by measuring fluorescence. In experiment 3, via flow cytometry, the number of cells with surface MHC class II proteins were determined. Data from the three groups in each experiment were compared using analysis of variance Tukey-Kramer tests. RESULTS: Macrophages and PBMC from rats in the OP group released significantly more TNF-alpha than cells from rats in the LC ( p < 0.05) or AC ( p < 0.05) groups. Macrophages from rats in the OP group released significantly less H2O2 than cells from the AC ( p < 0.01) and LC ( p < 0.05) groups. There was no difference between the AC and LC results. No significant differences in PBMC H2O2 release were noted among any of the groups. OP group macrophages expressed significantly less MHC class II antigen than did AC group macrophages ( p < 0.05). No differences were noted among the LC results and either the OP or AC group's outcomes. No differences were noted in PBMC MHC class II expression among any of the groups. CONCLUSIONS: In all instances, the LC group's macrophage results were similar to the AC group's results. OC group macrophages produced significantly more TNF-alpha and less H2O2 than both the AC and LC groups. MHC class II protein expression was less for the OC group than for the AC group. OC group PBMCs produced more TNF-alpha. No differences in PBMC H2O2 release or MHC class II expression were noted. Laparoscopic methods better preserves the baseline values of the parameters studied.

Persistent post-laparoscopy pneumoperitoneum.

BACKGROUND: Persistent pneumoperitoneum after a laparoscopic operation can represent either residual postoperative pneumoperitoneum or free intraperitoneal gas released from the gastrointestinal tract. This animal study was conducted to better characterize the extent and duration of postoperative pneumoperitoneum as detected by computed tomography (CT). METHODS: Five pigs underwent cholecystectomy, four laparoscopically and one open. All pigs were followed serially with upright chest radiographs and abdominal CT scans beginning immediately postoperatively and continuing daily until resolution of pneumoperitoneum as detected by both imaging modalities. All radiographs and CT scans were reviewed by dedicated radiologists who reported the extent and duration of pneumoperitoneum in a blinded fashion. RESULTS: Pneumoperitoneum resolved on upright chest radiographs in all five pigs by or on postoperative day 1. Serial CT scans demonstrated that the laparoscopic group had either resolution of pneumoperitoneum or minimal persistence of free intraperitoneal gas by postoperative day 2. In contrast, the single pig in the open group had CT evidence of persistent pneumoperitoneum through postoperative day 6. CONCLUSIONS: In the pig model, small pockets of free intraperitoneal gas detected by CT scanning are expected to resolve by postoperative day 2 following laparoscopic surgery. Persistence of pneumoperitoneum beyond this interval is abnormal and may represent a perforated viscus. Whereas a prospective CT imaging study in humans is not ethically feasible, we believe that parallel conclusions between the pig and human may be drawn.

Ultrasound and sestamibi scan as the only preoperative imaging tests in reoperation for parathyroid adenomas.

BACKGROUND: In an effort to determine an efficient algorithm for the evaluation of patients with parathyroid adenomas in the reoperative setting, we explored the combination of using ultrasound scans (US) and sestamibi scintigraphy as the only preoperative imaging tests. METHODS: We analyzed the outcomes of 62 consecutive patients who were treated between January 1995 and May 1999 and who were referred for persistent primary hyperparathyroidism after initial surgical exploration, at which time no abnormal parathyroid glands had been found. Although all patients underwent US, computed tomography scan, magnetic resonance imaging, and sestamibi scan, we analyzed the success of localization and reoperation using only the results of US and sestamibi scan. RESULTS: Sixty-one patients (98%) underwent curative reoperations. The sensitivity, positive predictive value, and accuracy for US were 90%, 86%, and 84%, respectively; the corresponding values for sestamibi imaging were 78%, 94%, and 74%, respectively. In 58 of 62 cases (94%) preoperative US and/or sestamibi scan accurately identified the adenoma. In 3 patients for whom combined US and sestamibi scan were inaccurate, 1 adenoma was found by intraoperative US in the strap muscle; 1 adenoma was found by blind cervical thymectomy, and 1 adenoma was found by planned sternotomy that was based on computed tomography findings. CONCLUSIONS: This study supports an algorithm of obtaining US and sestamibi scan as the initial and perhaps only preoperative localization tests for patients with primary hyperparathyroidism after failed operation, at which time no abnormal glands had been found.