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

A Prospective Study Using Propensity Score Matching to Compare Long-term Survival Outcomes After Robotic-assisted, Laparoscopic, or Open Liver Resection for Patients With BCLC Stage 0-A Hepatocellular Carcinoma

OBJECTIVE

To compare the short- and long-term outcomes of robot-assisted (RALR), laparoscopic (LLR), or open liver resection (OLR) in the treatment of Barcelona Clinic Liver Cancer (BCLC) stage 0-A hepatocellular carcinoma (HCC).

SUMMARY BACKGROUND DATA

Following the Balliol IDEAL classification, long-term oncological outcomes can be used to evaluate the value of minimally invasive techniques in the treatment of HCC, and to assess whether they should become a standard practice.

METHODS

Data from prospective cohorts of patients with BCLC stage 0-A HCC who underwent curative liver resection using OLR, LLR, or RALR at Tongji Hospital were reviewed. The short-term and long-term oncological outcomes of these 3 different surgical approaches after adequate follow-up were compared using propensity score matching to reduce selection bias.

RESULTS

Of 369 patients included in this study (71, RALR; 141, LLR; and 157, OLR), 56 patients in each of the 3 groups were chosen for further comparison, after propensity score matching. In the minimally invasive group (RALR+LLR), both the operative time and duration of Pringle's maneuver were significantly longer than those in the OLR group; however, the length of hospital stay was significantly shorter. There were no significant differences in the other intraoperative parameters and the incidence of postoperative complications among the 3 groups. HCC recurrence in the minimally invasive group when compared with the OLR group was characterized by a significantly higher proportion of single lesion or early-stage HCC. However, there were no significant differences in the 5-year disease-free survival (63.8%, 54.4%, and 50.6%) or overall survival rates (80.8%, 78.6%, and 75.7%, respectively) among the 3 groups. Clinically significant portal hypertension was the only risk factor that negatively affected the 5-year disease-free survival rate. Multivariate Cox regression analysis showed that clinically significant portal hypertension, serum alpha-fetoprotein level (≥400 ng/mL), and Edmondson-Steiner grading (III+IV) were independent risk factors for poor long-term survival.

CONCLUSION

Both robotic and laparoscopic hepatectomies were safe and effective for patients with BCLC stage 0-A HCC when compared with open hepatectomy.

Perioperative and long-term survival outcomes of laparoscopic versus laparotomic hepatectomy for BCLC stages 0-A hepatocellular carcinoma patients associated with or without microvascular invasion: a multicenter, propensity score matching analysis

PURPOSE

To analyze the long-term oncological outcomes of Barcelona Clinic Liver Cancer (BCLC) stages 0-A hepatocellular carcinoma (HCC) patients associated with or without microvascular invasion (MVI) treated with laparoscopic versus laparotomic liver resection.

METHODS

Clinicopathological data of HCC patients with BCLC stages 0-A from four medical centers were retrospectively reviewed. The survival outcomes of patients who underwent laparoscopic hepatectomy were compared with those who underwent laparotomic hepatectomy. Subgroup analyses in terms of MVI were further performed to explore the effect of surgical approaches on the long-term survival outcomes. Propensity score matching (PSM) analysis was used to match patients between the laparoscopic and laparotomic resection groups in a 1:1 ratio.

RESULTS

495 HCC patients at BCLC stages 0-A were enrolled, including 243 in the laparoscopic resection group and 252 in the laparotomic resection group. Laparoscopic resection group had a shorter operation time, less blood loss, a lower frequency of blood transfusion and postoperative complication rates. The laparoscopic resection group had a significantly better overall survival (OS) and recurrence-free survival (RFS) than the laparotomic resection group before and after PSM. Subgroup analysis demonstrated that OS and RFS of patients without MVI were remarkably better in the laparoscopic resection group compared with the laparotomic resection group. However, no significant differences in OS and RFS between the two groups were found in patients with MVI after PSM.

CONCLUSIONS

Pure laparoscopic hepatectomy for patients with BCLC stages 0-A HCC can be performed safely with favorable perioperative and long-term oncological outcomes at high-volume liver cancer centers, regardless of the presence of MVI.

Significance of Preoperative Prognostic Nutritional Index in the Perioperative Management of Gastric Cancer

BACKGROUND

Malnutrition leads to accelerated tumor progression through the suppression of tumor immunity. The present study examined the significance of the preoperative prognostic nutritional index (PNI) for predicting postoperative survival outcomes in gastric cancer (GC).

METHODS

A total of 447 patients who underwent curative gastrectomy for GC were included in the present study. PNI was calculated as 10 × serum albumin (g/dl) + 0.005 × total lymphocyte counts (per mm³). The prognostic impact of preoperative PNI was examined using two multivariate analysis models.

RESULTS

The optimal cutoff value of preoperative PNI for predicting overall survival (OS) was 48 based on a receiver operating characteristic curve. The 5-year OS rate was 59.5% in the PNI<48 group and 91.3% in the PNI≥48 group (p<0.001). In the first multivariate survival analysis where all explanatory variables were composed of preoperative factors alone, a PNI<48 (hazard ratio [HR] 3.33; 95% confidence interval [CI] 2.01-5.56, p<0.001), upper-third GC and cT2-T4 were identified as independent indicators of a poor OS. In the second survival analysis where explanatory variables were composed of preoperative, intraoperative, and pathological factors, a PNI<48 (HR 2.80; 95% CI 1.65-4.78, p<0.001), hypertension, open gastrectomy, intraoperative blood loss≥100g, pT2-T4, and pN+ were independent prognostic factors.

CONCLUSION

Preoperative PNI may be a useful predictor of postoperative survival outcomes both before and immediately after surgery in GC. Appropriate perioperative interventions and the meticulous surveillance of GC relapse are necessary for patients with PNI<48.

Cellular Immunoprofile of Peritoneal Environment During a HIPEC Procedure

BACKGROUND

We characterized the peritoneal immune cellular profile during cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) in this pilot study.

METHODS

We prospectively performed flow cytometric analysis of peritoneal fluid collected at laparotomy and during HIPEC at 0, 30, 60, and 90 min. Analysis consisted of standard flow cytometric leukocyte gating and the use of antibodies for stem cells, B lymphocytes, T-helper, T-suppressor, and natural killer (NK) cells.

RESULTS

The mean peritoneal carcinomatosis index (PCI) score was 19.8 ± 11.5 (median 19). Twelve patients had a completeness of cytoreduction (CCR) score of 0-1, and three patients had a CCR score of ≥ 2 (20%). The proportion of peritoneal NK cells remained stable (p = 0.655) throughout perfusion. The CD4/CD8 ratio (p = 0.019) and granulocyte/lymphocyte ratio (p = 0.018) evolved during cytoreduction, with no further change during HIPEC. Two distinct temporal patterns of peritoneal T lymphocytes became evident (the 'high' and 'low' CD4/CD8 ratio groups) and patients maintained their high versus low peritoneal CD4/CD8 ratio status throughout the duration of HIPEC. High CD4/CD8 was associated with longer cytoreduction (p = 0.019) and borderline higher PCI score (p = 0.058). No association was identified with age (p = 0.131), sex (p = 1.000), CCR status (p = 0.580), occurrence of complication (p = 0.282), or ascites volume (p = 0.713).

CONCLUSION

The cellular immunoprofile of peritoneal fluid during HIPEC is stable but changes during cytoreduction. Two distinct immune groups emerged, based on CD4/CD8 ratios in the peritoneal perfusate. Further studies are warranted to evaluate peritoneal immunity and the clinical significance of novel peritoneal immune phenotype.

Surgical trauma-induced immunosuppression in cancer: Recent advances and the potential therapies

Surgical resection remains the mainstay treatment for solid cancers, especially for localized disease. However, the postoperative immunosuppression provides a window for cancer cell proliferation and awakening dormant cancer cells, leading to rapid recurrences or metastases. This immunosuppressive status after surgery is associated with the severity of surgical trauma since immunosuppression induced by minimally invasive surgery is less than that of an extensive open surgery. The systemic response to tissue damages caused by surgical operations and the subsequent wound healing induced a cascade alteration in cellular immunity. After surgery, patients have a high level of circulating damage-associated molecular patterns (DAMPs), triggering a local and systemic inflammation. The inflammatory metrics in the immediate postoperative period was associated with the prognosis of cancer patients. Neutrophils provide the first response to surgical trauma, and the production of neutrophil extracellular traps (NETs) promotes cancer progression. Activated macrophage during wound healing presents a tumor-associated phenotype that cancers can exploit for their survival advantage. In addition, the amplification and activation of myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) or the elevated programmed death ligand-1 and vascular endothelial growth factor expression under surgical trauma, exacerbate the immunosuppression and favor of the formation of the premetastatic niche. Therapeutic strategies to reduce the cellular immunity impairment after surgery include anti-DAMPs, anti-postoperative inflammation or inflammatory/pyroptosis signal, combined immunotherapy with surgery, antiangiogenesis and targeted therapies for neutrophils, macrophages, MDSCs, and Tregs. Further, the application of enhanced recovery after surgery also has a feasible outcome for postoperative immunity restoration. Overall, current therapies to improve the cellular immunity under the special condition after surgery are relatively lacking. Further understanding the underlying mechanisms of surgical trauma-related immunity dysfunction, phenotyping the immunosuppressive cells, and developing the related therapeutic intervention should be explored.

Perioperative Detection of Circulating Tumor Cells in Radical or Partial Nephrectomy for Renal Cell Carcinoma

BACKGROUND

The current study was conducted to clarify the frequency of systemic circulating tumor cells (CTCs) appearing after surgery for renal cell carcinoma and to evaluate the differences in postoperative CTCs between different surgical procedures.

METHODS

This prospective, cohort study included 60 consecutive patients who underwent laparoscopic radical nephrectomy (RN) (n = 22), laparoscopic partial nephrectomy (PN) (n = 19), open RN (n = 8), or open PN (n = 11). In this study CTCs were measured by the FISHMAN-R system, and CTCs drawn from a peripheral artery were collected just before and immediately after surgery. The number of pre- and postoperative CTCs and the perioperative changes in CTCs were measured for each surgical method.

RESULTS

Six patients were excluded from the current analyses. Preoperative CTCs did not differ significantly by surgical approach (laparoscopic RN: 3.4 ± 4.2; laparoscopic PN: 3.4 ± 4.1; open RN: 7.7 ± 6.8; open PN: 6.0 ± 7.6; P = 0.19). Open RN resulted in a significantly greater number of postoperative CTCs (laparoscopic RN: 4.8 ± 3.7; laparoscopic PN: 7.9 ± 9.1; open RN: 22.5 ± 26.3; open PN: 6.4 ± 6.3; P < 0.001) and perioperative changes in CTCs (laparoscopic RN: 1.3 ± 5.3; laparoscopic PN: 4.5 ± 9.6; open RN: 14.7 ± 25.0; open PN: 0.4 ± 6.3; P < 0.001). No significant differences in these were observed among the three groups except in the open RN group. In the multivariate analysis, the surgical approach was significantly correlated with the number of postoperative CTCs (P = 0.016) and the perioperative change in CTCs (P = 0.01).

CONCLUSIONS

This proof-of-concept study indicated that after surgery, more cancer cells can be expelled into the bloodstream, especially after open RN. Sufficient and careful follow-up assessment for the emergence of distant metastases is needed for patients undergoing open RN.

Postoperative Serum C-Reactive Protein Level Predicts Long-term Outcomes in Stage I Gastric Cancer

BACKGROUND

The aim of this study was to investigate the prognostic impact of postoperative systemic inflammation in patients with stage I gastric cancer.

METHODS

This study reviewed the medical records of 470 patients with stage I gastric cancer who underwent gastrectomy. The postoperative serum C-reactive protein (CRP) level on postoperative days (PODs) 1 and 3 and its peak value were evaluated as prognostic factors. A receiver operating characteristics curve analysis was performed to determine their cut-off values.

RESULTS

The CRP level on POD 3 (P = 0.001) and the peak CRP level (P = 0.007) were significantly associated with the overall survival rate. In the multivariate analysis, the CRP level on POD 3 (P = 0.002) and the peak CRP level (P = 0.008) were identified as independent predictors of the overall survival. The high CRP on POD3 group had significantly higher mortality rate from relapse of gastric cancer (P = 0.001) and infectious disease (P = 0.003) than the low CRP on POD 3 group. The CRP level on POD 3 was significantly associated with the patient sex, surgical procedure, duration of the operation, amount of blood loss, postoperative infectious complication, and peak CRP level.

CONCLUSIONS

The serum CRP level during the early postoperative period predicts the long-term outcomes in stage I gastric cancer. The present study suggests a significant influence of postoperative systemic inflammation on the survival of patients with stage I gastric cancer.

More Reasonable Animal Model for Study the Effect of Pneumoperitoneum on Abdominal Tumor Cells

Background:

Many animal experimental studies showed that abdominal tumor cells will be widely spread during laparoscopic treatment and grow into metastases. These results are different from clinical observations. There is a hypothesis that too much tumor cells was injected in the animals lead to the results of theses bias. We aim to learn the difference of abdominal cavity volume between human body and the nude mice and to determine reasonable amount of tumor cells in the animal experiments.

Methods:

The insufflated CO₂ volume which represents the capacity of the abdominal cavity was recorded during laparoscopic process in 212 patients and 20 nude mice respectively, the relative volume of nude mice and human body was calculated. Based on data from the literature and this study , the amount of tumor cells in the animal experiments was determined. According to these data, we set up a new animal model and a traditional one respectively, and compared the rate of successful modeling and tumor formation between two animal models.

Results:

The intraperitoneal volumes of humans and nude mice were 3.01±0.36 L and 0.011±0.001 L respectively.The number of tumor cells that be uesd in animal should be approximately 0.26×10⁵ in terms of known data in human beings. Compared with the traditional animal model which formed a large number of intraperitoneal tumor metastasis, the new animal model was shows more moderately, and the rate of successful modeling was similar.

Conclusion:

In animal experiments, to simulate the clinical situation, about 0.26×10⁵ tumor cells should be inject in peritoneal cavity of the nude mice.

Advantages of laparoscopic compared to conventional surgery are not related to an innate immune response of peritoneal immune activation: an animal study in rats

PURPOSE

Laparoscopic surgery (LS) has proved superior compared to conventional surgery (CS) regarding morbidity, length of hospital stay, rate of wound infection and time until recovery. An improved preservation of the postoperative immune function is assumed to contribute to these benefits though the role of the local peritoneal immune response is still poorly understood. Our study investigates the peritoneal immune response subsequent to abdominal surgery and compares it between laparoscopic and conventional surgery to find an immunological explanation for the clinically proven benefits of LS.

METHODS

Wistar rats (N = 140) underwent laparoscopic cecum resection (LCR; N = 28), conventional cecum resection (CCR; N = 28), laparoscopic sham operation (LSO; N = 28), conventional sham operation (CSO; N = 28), or no surgical treatment (CTRL; N = 28). Postoperatively, peritoneal lavages were performed, leukocytes isolated and analyzed regarding immune function and phagocytosis activity.

RESULTS

Immune function was inhibited postoperatively in animals undergoing LCR or CCR compared to CTRL reflected by a lower TNF-α (CTRL 3956.65 pg/ml, LCR 2018.48 pg/ml (p = 0.023), CCR 2793.78 pg/ml (n.s.)) and IL-6 secretion (CTRL 625.84 pg/ml, LCR 142.84 pg/ml (p = 0.009), CCR 169.53 pg/ml (p = 0.01)). Phagocytosis was not affected in rats undergoing any kind of surgery compared to CTRL. Neither cytokine secretion nor phagocytosis activity differed significantly between laparoscopic and conventional surgery.

CONCLUSIONS

According to our findings the benefits associated with LS compared to CS cannot be explained by differences in the postoperative peritoneal innate immune response. Further studies are needed to elucidate the causes for a more favorable postoperative outcome in patients after LS compared to CS.

Laparoscopic cholecystectomy in elderly patients: an evaluation of immunity

OBJECTIVE

We sought to investigate the impact of laparoscopic cholecystectomy (LC) on the inflammatory response and immunological function of elderly patients compared with that on the younger ones.

METHODS

Between June 2012 and June 2013, this prospective study investigated a total of 112 patients having the surgery of LC due to symptomatic cholelithiasis or polyps, among whom 52 were elderly patients with the age beyond 65 years old and the remaining 60 were younger than the age. Peripheral venous blood samples were taken from these patients prior to surgery and on post-operative days 1, 3 and 7, respectively. The perioperative clinical outcomes and immunological function results were analyzed and compared between the two groups divided by age.

RESULTS

The demographics of the two groups did not differ except for the age. Surgical trauma seemed more serious for elderly patients as illustrated by the longer operating time, hospital stay and more quantity of patients got complication. Both groups indicated changes in inflammatory and immune aspects. Compared with the younger ones, elderly patients showed less quantity of preoperative basic immune cells, delayed immune responses after the surgical trauma of LC and hyporeactivity of inflammatory response when accepting LC.

CONCLUSIONS

An examination of the inflammatory reaction and immune response after LC demonstrated that there are significant differences observed in two groups divided by age. Further studies with more samples are required to determine the exact relationship of perioperative immune change and higher adverse outcome rate of aged people.

Comparison of open and retroperitonoscopic donor nephrectomy in terms of lipid and protein peroxidation responses

BACKGROUND

This study was designed to compare donors who underwent open (ODN) versus retroperitonoscopic nephrectomy (RDN) in terms of intra-operative oxidative stress and recipients graft function in the early postoperative period.

METHODS

Among 40 patients who underwent donor nephrectomy, 23 were operated via an open method and 17 via retroperitonoscopic method. To analyze oxidative stress, we measured plasma levels of malondialdehyde (MDA), protein carbonyl, and protein sulfhydryl moieties in donor venous blood before induction of anesthesia and postoperatively at 0, 6, and 24 hours. The influence of oxidative stress on graft function was evaluated by means of the postoperative 5th day recipient creatinine and estimated glomerular filtration rate (eGFR) Modification of Diet in Renal Disease Formula (MDRD) to evaluate delayed graft function (DGF) status.

RESULTS

ODN patients showed significantly higher 24-hour mean levels of MDA, (6,139 ± 1,854 vs 4,813 ± 1,771 nmol/L; P = .01), protein carbonyl (366 ± 64 vs 311 ± 62 μmol/L; P = .01) and protein sulfhydryl (468 ± 110 vs 386 ± 75 μmol/L; P = .01) moieties compared with those RDN patients. However, ODN and RDN recipients were similar in terms of 5th day mean creatinine and eGFR (1.1 ± 0.3 vs 1.4 ± 0.8 mg/dL and 69.15 ± 12.24 vs 56.31 ± 25.2, respectively) and DGF status (4.4% [1/23] vs 5.9% [1/17], respectively).

CONCLUSIONS

Although ODN donors were more prone to intra-operative oxidative stress than RDN donors, based on significantly higher levels of oxidative stress markers, this difference seems to not significantly influence recipients early graft function.

Recognizing risk: bowel resection in the chronic renal failure population

BACKGROUND

There is a paucity of quality data on the effects of chronic kidney disease in abdominal surgery. The aim of this study was to define the risk and outcome predictors of bowel resection in stage 5 chronic kidney disease using a large national clinical database.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried from years 2005-2010 for major bowel resection in dialysis-dependent patients. Patient demographics, preoperative risk factors, and intraoperative variables were evaluated. Primary endpoints were mortality and morbidity after 30 days. Predictors of outcome were assessed by multivariate regression.

RESULTS

The study included 1,685 patients with chronic kidney disease undergoing bowel resection. Overall mortality and morbidity were 27.5 and 58.3 %, respectively. Acute presentation was the strongest predictor of mortality (OR 2.39, CI 1.54-3.72, p < 0.001). Other predictors of mortality included hypoalbuminemia (OR 2.12, CI 1.39-3.24, p < 0.001), pulmonary comorbidity (OR 2.25, CI 1.67-3.03, p < 0.001), and cardiac comorbidity (OR 1.54, CI 1.16-2.05, p = 0.003).

CONCLUSION

This study demonstrates that bowel resection in patients with chronic kidney disease confers a high mortality risk. Preoperative optimization of comorbid conditions may reduce mortality after bowel resection in dialysis-dependent patients. In addition, laparoscopy was associated with a reduction in postoperative morbidity suggesting that it should be used preferentially.

Laparoscopic and open splenectomy for splenomegaly secondary to liver cirrhosis: an evaluation of immunity

OBJECTIVE

We sought to investigate the perioperative inflammatory response and immunological function of patients with portal hypertension-induced splenomegaly who underwent laparoscopic (LS) or open splenectomy (OS).

METHODS

This prospective study investigated a total of 34 patients with splenomegaly due to portal hypertension who underwent either LS (n = 18) or OS (n = 16) between May 2009 and September 2010. Peripheral venous blood samples were taken from these patients prior to surgery and on postoperative days (POD) 1, 3, and 7. The perioperative clinical outcomes and immunological function results were analyzed and compared within each surgical group.

RESULTS

The demographics of the two groups did not differ. The patients in the LS group experienced longer operating time, less intraoperative blood loss, earlier resumption of diet, and shorter postoperative hospital stay. Both the open and laparoscopic groups exhibited statistically significant differences in interleukin -6 and C-reactive protein levels, and total lymphocyte, CD4 T, and natural killer cell numbers on POD 1 and 3 compared with pre splenectomy. The immune responses in the LS group were significantly lower than those in the OS group. The LS group exhibited better preserved cellular immune response and faster recovery than the OS group on POD 7.

CONCLUSIONS

An examination of the inflammatory reaction and cellular immune response after LS and OS demonstrated that there are significant differences in the immune responses observed in the two groups. Further human studies are required to determine the permanent effects of LS on immune function.

Immune cell populations and cytokine production in spleen and mesenteric lymph nodes after laparoscopic surgery versus conventional laparotomy in mice

PURPOSE

There is evidence that open as well as minimally invasive abdominal surgery impair post-operative innate and acquired immune function. To compare the impact of these approaches as well as the one of different peritoneal gas exposures on immune function, we investigated cellular as well as cytokine-based immune parameters in mesenteric lymph nodes and the spleen postoperatively.

METHODS

Mice (n = 26) were randomly assigned to the 4 study groups: (1) sham controls undergoing anesthesia alone, (2) laparotomy, and (3) air, or (4) carbon dioxide pneumoperitoneum. Mice were sacrificed 48 h after the intervention, and their spleens and mesenteric lymph nodes were harvested. Cytokine production (TNF-α, IL-6, IL-10, and IFN-γ), splenic T cell subpopulations (cytotoxic T cells, T helper cells, and regulatory T cells) were analyzed.

RESULTS

TNF-α production of splenocytes 16 h after ex vivo lipopolysaccharides (LPS) stimulation was significantly increased in the laparotomy group compared to all other groups. In contrast, TNF-α production of lymph node cells and IL-6 production of splenocytes after ex vivo LPS stimulation did not differ significantly between the groups. The numbers of regulatory T cells (Treg) in the spleen differed between groups. A significant reduction in Treg cell frequency was detected in the CO(2) insufflation group compared to the laparotomy and the air insufflation group.

CONCLUSION

Our findings demonstrate a distinct difference in immune effector functions and cellular composition of the spleen with regard to splenic TNF-α production and increased numbers of Treg cells in the spleen. These findings are in line with a higher peritoneal inflammatory status consequent to peritoneal air rather than CO(2) exposure. Treg turned out to be key modulators of postoperative dysfunction of acquired immunity.

Effects of CO(2) pneumoperitoneum on peritoneal macrophage function and peritoneal metastasis in mice with gastric cancer

BACKGROUND

Whether laparoscopy with CO(2) pneumoperitoneum affects the peritoneal metastasis of gastric cancer is a pressing question. In light of the important impact change in peritoneal macrophage function has on the peritoneal metastasis of gastric cancer, this study investigated the change in peritoneal macrophage function in gastric cancer in the CO(2) pneumoperitoneum environment, as well as its effect on the peritoneal metastasis of gastric cancer.

METHODS

An orthotopic transplantation model of murine forestomach carcinoma was established using the 615 mouse line. The mice bearing tumors were randomly divided into four groups (30 mice each group): anesthesia alone, laparotomy, mini-laparotomy, and CO(2) insufflation. After the operation, peritoneal macrophages were collected from 6 mice in each group and cultured. The phagocytosis of neutral red by macrophages and the levels of NO, TNF-α, IL-10, and VEGF produced by macrophages were measured after 12, 24, 48, and 72 h of culture. The remaining mice were observed after 2 weeks for the rate of peritoneal metastasis of forestomach carcinoma cells and the total weight of implanted nodules.

RESULTS

In the laparotomy group, 4 mice died intraoperatively and 2 died in the CO(2) insufflation group. The uptake of neutral red by peritoneal macrophages and the levels of NO, TNF-α, IL-10, and VEGF secreted by peritoneal macrophages in the laparotomy group and mini-laparotomy group after 12 h of culture were all significantly higher than those in the anesthesia-alone group (p < 0.05). The corresponding levels in the CO(2) insufflation group after 12 h were all significantly lower than those in the anesthesia-alone group (p < 0.05). There were no significant differences among the four groups at 24, 48, and 72 h after culture. Comparing with those in the laparotomy group, the uptake of neutral red by peritoneal macrophages and the levels of NO, TNF-α, IL-10, and VEGF secreted by peritoneal macrophages in the CO(2) insufflation group were all significantly lower after 12 h of culture (p < 0.05), but did not differ significantly at 24, 48, and 72 h of culture (p > 0.05), and did not differ significantly in the mini-laparotomy group at all the time (p > 0.05). The rate of peritoneal metastasis of mouse forestomach carcinoma was 50% in the laparotomy group, 45.83% in the mini-laparotomy group, and 45.45% in the CO(2) insufflation group; this difference was not statistically significant (p > 0.05). The total weight of implanted nodules of mouse forestomach carcinoma was 1.02 ± 0.38 g in the laparotomy group, 0.97 ± 0.41 g in the mini-laparotomy group, and 0.93 ± 0.45 g in the CO(2) insufflation group, which was not a statistically significant difference (p > 0.05).

CONCLUSION

CO(2) pneumoperitoneum neither significantly changes the phagocytosis and cytokine secretion functions of peritoneal macrophages in gastric cancer-bearing mice nor significantly promotes peritoneal metastasis of gastric cancer.

Pulmonary and peritoneal inflammatory findings in transgastric NOTES compared with laparoscopy: pooled analysis from randomized porcine survival studies

BACKGROUND

Laparoscopy, which is a minimally invasive surgery, is associated with decreased peritoneal adhesions and inflammatory response compared with laparotomy.

OBJECTIVE

To evaluate whether natural orifice transluminal endoscopic surgery (NOTES) leads to an attenuated peritoneal response compared with laparoscopy.

DESIGN

Pooled histologic analysis from 2 randomized porcine trials.

SETTING

Laboratory.

INTERVENTION

Histologic analysis of swine undergoing diagnostic laparoscopy, diagnostic NOTES peritoneoscopy, NOTES with transgastric mesh placement, or diagnostic endoscopy (no gastrotomy) followed by laparoscopic mesh placement.

MAIN OUTCOME MEASUREMENTS

The presence and grade of inflammation in necropsy specimens of lung, liver, and spleen as reviewed by a blinded veterinary pathologist.

RESULTS

Four NOTES mesh animals exhibited mesh infections at necropsy. Tissue from 48 swine were available for analysis. Pulmonary inflammation, liver fibrosis, and spleen capsulitis were the primary findings. No difference was seen in the incidence of each finding among groups. The severity of the pulmonary inflammation in the laparoscopy group was significantly higher than in the NOTES groups. The NOTES mesh group exhibited significantly more severe liver fibrosis and spleen capsulitis. There was no difference between clinical behavior, serum white blood cell count, or peritoneal white blood cell count among groups in either study. Intra-abdominal pressures during NOTES were lower than during laparoscopy.

LIMITATIONS

Pooled analysis of 2 separate studies.

CONCLUSION

More severe pulmonary inflammation was found in animals undergoing longer laparoscopic procedures with higher intra-abdominal pressures. Intraperitoneal inflammation was most significant with transgastric mesh placement, likely caused by infections.

Designing a robotic colorectal program

Designing a successful robotic colorectal program requires consideration and implementation of several important concepts with continued perseverance through many obstacles that may arise. The ideal strategy is to establish a core group of committed individuals, define the goals and vision of the program, enlist corporate partners, and gain financial support with a sound business, educational, and research plan. Factors such as cost, limited availability, and demanding training are often hindrances to the implementation of a new robotic colorectal program while scheduling conflicts and inadequate resources may present obstacles to developing a colorectal program in institutions with existing robotic surgical programs. In developing a business plan one should consider the potential for increased patient referrals and the benefits of reduced hospital stay, decreased infection and complication rates, and quicker recovery compared with open surgical procedures. The optimal robotics surgical staff will include those most eager to be trained, as they are highly motivated and have the greatest enthusiasm to succeed. The early foundation of accomplishment will be vital to the long-term success of the program. In addition to building the ideal surgical team, patient selection is one of the most crucial considerations in developing a successful robotics program. Initiating a positive impression for robotic-assisted laparoscopic colorectal procedures will be an important precursor to continued success. Likewise, maintaining a regular schedule of procedures may advance the team's competencies and deter complacency. Proper planning, deliberate implementation, and sustained perseverance are key to the successful initiation of a robotic colorectal program.

The efficacy of preoperative PET/CT for prediction of curability in surgery for locally advanced gastric carcinoma

Background

The benefits of preoperative ¹⁸FDG-PET/CT for gastric cancer remain uncertain. The aim of this study was to investigate the effects of preoperative ¹⁸FDG-PET/CT on the surgical strategy for locally advanced gastric cancer retrospectively.

Methods

From January 2007 to November 2008, ¹⁸FDG-PET/CT was performed in 142 patients who had been diagnosed with advanced gastric cancer by computed tomography or gastrofiberscope findings.

Results

Detection rates were 88.7% (126/142) for primary tumors and 24.6% (35/142) for local lymph nodes (LN). Nine patients with metastatic lesions underwent induction chemotherapy without operation. Of 133 patients subjected to operation, positive FDG uptake in primary tumors (p = 0.047) and local lymph nodes (p < 0.001) was related to non-curable operations. The mean standard uptake value (SUV) of primary tumors of patients who underwent non-curable operations was significantly higher than that of patients with curable operations (p = 0.001). When the SUV was greater than 5 and FDG uptake of LN was positive, non-curable operations were predicted with a sensitivity of 35.2%, a specificity of 91.0% and an accuracy of 76.7%.

Conclusions

High SUV of the primary tumor and positive FDG uptake in local lymph nodes at PET/CT could predict non-curative resection in locally advanced gastric cancer. Therefore, information from preoperative PET/CT can help physician decisions regarding other modalities without laparotomy.

Is there a role for a strict incision length criterion for determining conversions during laparoscopic colorectal resection?

PURPOSE

There's no consensus about what defines a conversion for laparoscopic-assisted colorectal resection (LACR). This study's goal was to assess the utility of a strict incision length (IL) definition of conversion (incision > 7 cm) and compare it with results obtained when the surgeon determined (SD) if a LACR had been successfully completed.

METHODS

The demographic and perioperative data for 580 elective LACRs were reviewed. The short-term outcomes for each conversion definition were determined and compared.

RESULTS

Conversion rates were 22% using the IL definition and 16% via the SD method. Both methods detected significant differences between completed and converted groups regarding the following: incision size, hospital stay, time to flatus, bowel movement, and regular diet as well as rate of wound infection and ileus. The IL method alone detected significant differences in the rate of pulmonary complications and BMI between the completed and converted groups.

CONCLUSIONS

The 2 methods yielded similar results for most parameters. The IL method better separated the patients in regard to 2 parameters. This method is objective and easy to apply; however, it may discriminate against obese patients whose extraction incisions are often longer. A conversion definition that considers BMI and IL is needed.

Application of stereology to study the effects of pneumoperitoneum on peritoneum

BACKGROUND

Scanning electron microscopy is unable to provide sufficient data to obtain definitive results for research into the morphologic effect of pneumoperitoneum on peritoneum. To overcome this difficulty, we adopted stereology to examine the effect of the type of gas insufflated, pressure, duration, and gas flow on morphologic alterations of peritoneum.

METHODS

Fifty SD rats were divided into ten groups. One group served as control. Pneumoperitoneum was established at 5 mmHg and 1.0 l/min gas flow for 1, 2 or 3 h with CO2 (in groups C1h, C2h, and C3h, respectively) or with He (in groups H1h, H2h, and H3h, respectively). CO2 pneumoperitoneum was further established at 8 mmHg and 1.0 l/min gas flow for 1 h (group C8p), at 5 mmHg and 2.0 l/min gas flow for 1 h (group C2f), and at 5 mmHg and 3.0 l/min gas flow for 1 h (group C3f). After the procedures, five specimens were sampled from anterior peritoneum and measured by stereological and electron-microscopic techniques.

RESULTS

Groups H1h and C1h, H2h and C2h, and H3h and C3h, respectively, were the same in terms of area fraction of basal lamina exposed and diameter of mesothelial cells (P>0.05). The magnitudes of peritoneal trauma in groups C2h, C3h, C8p, C2f, and C3f were significantly higher than that in group C1h (P<0.01), and the same result was observed in groups H2h and H3h against group H1h (P<0.01), and in group C3f against group C2f (P<0.01). Furthermore, the area fractions of basal lamina exposed in groups C3h and H3h were remarkably higher than those in groups C2h and H2h, respectively (P<0.01). The mechanism of basal lamina exposure comprises mesothelial cell desquamation and plasmatorrhexis.

CONCLUSIONS

Peritoneal morphologic trauma during pneumoperitoneum can be attributed to the pressure, duration, and gas flow instead of the type of gas insufflated.

Peritoneal changes due to laparoscopic surgery

Background

Laparoscopic surgery has been incorporated into common surgical practice. The peritoneum is an organ with various biologic functions that may be affected in different ways by laparoscopic and open techniques. Clinically, these alterations may be important in issues such as peritoneal metastasis and adhesion formation.

Methods

A literature search using the Pubmed and Cochrane databases identified articles focusing on the key issues of laparoscopy, peritoneum, inflammation, morphology, immunology, and fibrinolysis.

Results

Laparoscopic surgery induces alterations in the peritoneal integrity and causes local acidosis, probably due to peritoneal hypoxia. The local immune system and inflammation are modulated by a pneumoperitoneum. Additionally, the peritoneal plasmin system is inhibited, leading to peritoneal hypofibrinolysis.

Conclusion

Similar to open surgery, laparoscopic surgery affects both the integrity and biology of the peritoneum. These observations may have implications for various clinical conditions.

Comparison of immunologic outcomes of laparoscopic vs open approaches in clinical stage III colorectal cancer

PURPOSE

Improved survival in patients with stage III colon cancer after a laparoscopic colectomy (LC) has been reported by Lacy et al. (Lancet 359:2224-2229, 6), and preserved immunity was suggested as the reason for the survival advantage. The aim of our study was to clarify the existence of an immunological benefit after laparoscopic colon cancer surgery (LC) compared to open colon surgery (OC).

METHODS

From January 2006 to November 2007, 74 patients with clinical stage III colon cancer were prospectively assigned to undergo a LC (n = 35) or an OC (n = 39). The immune factors were examined preoperatively, and on the first and fifth days postoperatively (POD1 and POD5).

RESULTS

The cellular immune factors were significantly decreased; however, there was no significant difference between the LC and OC groups except for the mHLA-DR. The LC group had a better preserved mHLA-DR on POD5 than did the OC group (p = 0.015), in addition to a faster recovery (p < 0.005).

CONCLUSION

The mHLA-DR on POD5 was affected less by the LC compared to the OC. The LC demonstrated minimal immunological advantage when compared to the OC. However, further study is required to clarify the immunological benefits of the LC on colorectal cancer prognosis.

Postoperative peritoneal dissemination of ovarian cancer cells is not promoted by carbon-dioxide pneumoperitoneum at low intraperitoneal pressure in a syngenic mouse laparoscopic model with controlled respiratory support: a pilot study

STUDY OBJECTIVE

To investigate postoperative peritoneal dissemination of ovarian cancer cells in a syngenic mouse model with and without controlled respiratory support (CRS).

DESIGN

Randomized controlled trial (Canadian Task Force classification I).

SETTING

Academic facility.

SUBJECTS

Sixty-four female C57BJ6 mice.

INTERVENTIONS

Mice were randomly divided into 4 surgical groups: anesthesia alone group; 2 carbon-dioxide pneumoperitoneum groups, 1 with low (2 mm Hg) and 1 with high (8 mm Hg) intraperitoneal pressure (IPP); and finally the laparotomy group. Each of the 4 groups was then subdivided into one group with CRS and the other without. Mouse ovarian cancer cells were injected intraperitoneally just before surgery.

MEASUREMENTS AND MAIN RESULTS

A laparotomy was performed to evaluate postoperative peritoneal dissemination of ovarian cancer cells on postoperative day 14. A computerized analysis system was then used to evaluate peritoneal dissemination. In the groups with CRS, the peritoneal dissemination score was significantly higher in the laparotomy and high IPP groups compared with anesthesia alone (p <.0001 vs laparotomy, p <.002 vs high IPP) and low IPP (p <.0002 vs laparotomy, p <.004 vs high IPP) groups. No significant difference was detected between the low IPP and anesthesia alone groups.

CONCLUSION

Postoperative peritoneal dissemination of ovarian cancer cells is not promoted by a carbon-dioxide pneumoperitoneum with a low IPP in a mouse model with CRS when assessed on postoperative day 14.

Conversion of laparoscopic colon resection does not affect survival in colon cancer

BACKGROUND

Laparoscopic and open resections of colon cancer are considered oncologically equivalent treatment methods. Conversion of laparoscopic procedures, however, was associated with decreased survival in colon cancer patients in the only prior study examining this question. We conducted this study to evaluate the effect of conversion on survival.

METHODS

A series of consecutive patients treated with laparoscopic resection of colorectal cancer (n = 174) in the period 1998-2003 was evaluated retrospectively. Median follow-up was 51 months with a minimum of 3 years.

RESULTS

There was no statistically significant difference in all-cause mortality between laparoscopically completed and converted groups (22/143, 15.4% versus 8/31, 25.8%; OR 1.9, p = 0.164). Kaplan-Meier survival analysis did not show any survival difference between the two groups (p = 0.266).

CONCLUSIONS

The results of our study suggest there is no survival difference in patients requiring conversion of laparoscopic resection indicated for colorectal cancer. Further examination of this question is warranted to determine whether laparoscopic resection of colorectal cancer should be offered to all patients, including those at high risk for conversion.

Adhesion formation with open versus laparoscopic cholecystectomy: an immunologic and histologic study

BACKGROUND

This randomized study aimed to compare the reaction of the immune system to the process of postoperative adhesion formation after open and laparoscopic cholecystectomy.

METHODS

In this study, 20 mongrel dogs were used: 10 each in the laparoscopic and open cholecystectomy groups. Blood and peritoneal lavage samples were taken up to postoperative day 14, followed by second-look laparoscopy and reoperation to detect the rate of adhesion formation. Also, specimens were obtained from the liver bed for histology.

RESULTS

In the open cholecystectomy group, the white blood cell count was higher in blood samples and lower in lavage specimens. Adhesion formation was extensive, and the histologic immune reaction was more intensive in the open cholecystectomy group.

CONCLUSION

This randomized study proved that laparoscopic cholecystectomy was associated with less immune suppression, less inflammatory reaction, and therefore less adhesion formation than open cholecystectomy.

Peritoneal tissue-oxygen tension during a carbon dioxide pneumoperitoneum in a mouse laparoscopic model with controlled respiratory support

BACKGROUND

Previous animal studies suggested that the peritoneal environment during a carbon dioxide (CO(2)) pneumoperitoneum is hypoxic and that this may contribute to the formation of intra-abdominal adhesions or the growth of malignant cells. There is no study, however, that investigates the relationship between anaesthesia, ventilation and the laparoscopic peritoneal environment to the development of hypoxia. The objective of this study is to monitor the peritoneal tissue-oxygen tension (PitO(2)) under various conditions including anaesthesia alone, during a CO(2) pneumoperitoneum at both low and high intraperitoneal pressure (IPP), and laparotomy, in animal models with controlled respiratory support (CRS).

METHODS

C57BL6 mice were divided into eight groups (n = 5) consisting of anaesthesia alone or with CO(2) pneumoperitoneum at low (2 mmHg) or high (8 mmHg) IPP or undergoing laparotomy. Groups were further subdivided into those with or without CRS with endotracheal intubation and mechanical ventilation. Over the course of the 1 h procedure, PitO(2) was continuously monitored.

RESULTS

Protocol 1. The PitO(2) levels (104.2 +/- 7.8 mmHg, mean +/- SEM) in non-injured peritoneum during a CO(2) pneumoperitoneum at a low IPP were elevated approximately 2-fold over the levels during laparotomy (49.8 +/- 15.0 mmHg) in ventilated mice. Protocol 2. After insufflation with CO(2), the PitO(2) was immediately elevated and maintained at a higher level. Following laparotomy, it decreased immediately. This elevation was not seen with air insufflation.

CONCLUSION

In mice, a significant elevation in PitO(2) occurs during a CO(2) pneumoperitoneum at low IPP with CRS.

The role of the spleen in laparoscopy-associated inflammatory response

BACKGROUND

Carbon dioxide (CO(2)) pneumoperitoneum alters the inflammatory response in animal models of sepsis. The spleen is a key organ in inflammation and its removal was predicted to modify this effect.

METHODS

The acute phase inflammatory response to lipopolysaccharide (LPS) challenge in male rats was examined for the effects of splenectomy (spx) and the technique of removal (open or laparpscopic). A series of experiments compared LPS-only controls with LPS injection 2 or 9 days following open spx, lap CO2 spx, open sham, or lap CO2 sham. The method of splenectomy was studied by randomization to control, open spx, lap CO2 spx, lap helium (He) spx, or lap air spx with LPS challenge on postoperative day 2. Serum levels of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (INF-gamma) and, interleutin (IL) 10 were collected at multiple time points, assayed by commercial enzyme-linked immunosorbent assay, analyzed by analysis of variance.

RESULTS

Levels of TNF-alpha at 1.5 were significantly lower following open sham than following lap sham (p < 0.05). Splenectomy drastically reduced INF-gamma and TNF-alpha levels compared to controls (p < 0.05) on postoperative day 2. No method of spx preserved TNF-alpha or INF-gamma responses. Recovery of TNF-alpha response on day 9 was delayed in the spx groups.

CONCLUSIONS

Splenectomy dramatically reduces TNF-alpha and INF-gamma responses to LPS challenge, although by different mechanisms. Pneumoperitoneum-mediated modulation of the septic inflammatory response is partially dependent on the spleen.

Impact of carbon dioxide versus air pneumoperitoneum on peritoneal cell migration and cell fate

BACKGROUND

Postoperative systemic immune function is suppressed after open abdominal surgery, as compared with that after minimally invasive abdominal surgery. As a first line of defense, peritoneal macrophages (PMo) and polymorphonuclear neutrophil granulocytes (PMNs) are of primary importance in protecting the body from microorganisms. Previous studies have shown changes in these cell populations over time after open versus laparoscopic surgery. This study aimed to investigate the dynamics of cell recruitment and clearance of peritoneal cells.

METHODS

Female NMRI mice (33 +/- 2 g) were randomly assigned to carbon dioxide (CO2) or air insufflation. Intravasal cells with phagocytic capabilities were selectively stained by intravenous injection of the fluorescent dye PKH26 24 h before surgery. Gas was insufflated into the peritoneal cavity through a catheter, and the pneumoperitoneum was maintained for 30 min. Peritoneal lavage was performed 1, 3, 8, or 24 h after surgery. Apoptotic cells were assessed by flow cytometry using a general caspase substrate.

RESULTS

The total peritoneal cell count did not differ between groups. The PKH26-positive PMo level was significantly increased after CO2, as compared with air, at 1 h and 24 h. The ratio of apoptotic PMo did not differ between the groups. In the peritoneal lavage, polymorphonuclear leukocytes (PMNs) were tripled in the air group, as compared with the CO2 group, whereas the ratio of apoptotic PMNs was significantly decreased. There was a higher fraction of PKH26-positive PMNs after air exposure, as compared with that after CO2.

CONCLUSIONS

Air exposure triggered a higher transmigration rate of PMNs from the blood compartment into the peritoneal cavity and decreased PMN apoptosis, as compared with CO2. The lower proportion of PKH26-positive peritoneal macrophages in the air group might have been attributable to a higher inflammatory stimulation than in the CO2 group, leading to increased emigration of PMo to draining lymph nodes. All the findings underscore a complex cell-specific regulation of cell recruitment and clearance in the peritoneal compartment.

Cytokine response to surgical stress: comparison of pure laparoscopic, hand-assisted laparoscopic, and open nephrectomy

BACKGROUND AND PURPOSE

Laparoscopic surgery has been shown to induce less immune suppression than open surgery, presumably because there is less tissue trauma, a factor that may impact oncologic-disease control. The objective of this study was to compare the cytokine and stress response associated with pure laparoscopic, hand-assisted laparoscopic (HAL), and open nephrectomy.

MATERIAL AND METHODS

Fifteen female farm pigs (45-50 kg) underwent transperitoneal laparoscopic, handassisted (HAL), or open nephrectomy (N = 5 in each group). At 1, 4, 24, and 48 hours post-nephrectomy, blood and peritoneal fluid samples were collected for measurement of tumor necrosis factor (TNF) alpha, interleukin (IL)-1beta, and IL-6 using enzyme-linked immunosorbent assay (ELISA) techniques. Body temperature and serum glucose and cortisol were also measured.

RESULTS

No evidence of perioperative infection was detected in any animal through temperature and glucose monitoring. Operating time and blood loss were comparable among the three groups. Peak serum cortisol concentrations were significantly higher in the HAL group than in the pure laparoscopic group at 24 hours (P = 0.02). Serum TFNalpha concentrations were significantly lower in the pure laparoscopy group (40 +/- 6 pg/mL) than in the HAL and open-nephrectomy groups (81 +/- 6 pg/mL and 83 +/- 17 pg/mL, respectively; P < 0.05), although no differences between groups were found in the serum IL-1beta and IL-6 concentrations. Peritoneal IL-1beta was significantly higher in the HAL than in the open-nephrectomy group (2993 +/- 507 pg/mL and 733 +/- 185 pg/mL, respectively; P = 0.05). Peritoneal IL-6 was significantly lower in the pure laparoscopy group (694 +/- 234 pg/mL) than in the open-surgery group (1668 +/- 312 pg/mL) (P = 0.04).

CONCLUSION

Pure laparoscopic surgery in pigs elicits a less-robust cytokine response than HAL or open nephrectomy with respect to serum TNFalpha and peritoneal IL-6 concentrations, perhaps reflecting less impairment of the immune system. Clinical confirmation is required, and the implications with regard to oncologic tumor surveillance in humans require further study.

Effect of radiofrequency ablation of the liver on cell-mediated immunity in rats

We investigated the effect of radiofrequency ablation (RFA) of the liver on cell-mediated immunity in rats. Sprague-Dawley rats were divided into five groups: control group that did not have any procedure, a sham-operation group that underwent laparotomy, a lobectomy group that had left lateral lobectomy of the liver, a one-lobe RFA group that had RFA on the left lateral lobe of the liver, and a two-lobe RFA group that had RFA on the left lateral and left median lobe of the liver. Delayed-type hypersensitivity (DTH) was induced by challenging the ears of previously sensitized rats with 2,4-dinitro-1-fluorobenzene. Cell-mediated immunity was evaluated by direct measurement of the ear thickness and quantitative analysis of leukocytic infiltration of the tissue. The increased ear thickness was 42.0%, 69.2%, 61.8%, 46.7%, and 39.8% from the baseline one day after each procedure, and the mean leukocytic infiltration into the ear tissue was 3136.7, 3895.0, 3913.3, 2803.3, and 2316.7/mm(2) seven days after each procedure in the control, sham-operation, lobectomy, one-lobe RFA, and two-lobe RFA groups, respectively. In conclusion, RFA of the liver tissue can partially abolish the augmentation of DTH and leukocytic infiltration those were seen in the hepatic lobectomy and sham-operation groups. The procedure had a negative effect on cell-mediated immunity in rats, and the intensity of RFA showed a reverse correlation with cell-mediated immunity.

Hepatic carbohydrate metabolism in rats after laparotomy and laparoscopy

BACKGROUND

Portal venous and mesenteric blood flow are reduced by 40-60% in humans and animals during laparoscopic surgery compared to laparotomy. Little is known about whether these intraabdominal micro- and macrocirculatory changes are associated with alterations in the hepatic energy metabolism.

METHODS

We operated on male Sprague-Dawley rats, performing either laparoscopy (CO2, 6 mmHg; n = 27) or laparotomy (n = 28), and compared the results with two control groups: intraperitoneal (i.p.) endotoxin administration (n = 28, positive control) and anesthesia only (n = 28, negative control). We investigated the impact of the two different surgical techniques on daily food intake, body weight gain, glycogen content in the liver, levels of blood glucose, and liver function tests (LFTs) on postoperative days 1, 2, 4, and 8. Local (hepatic) and systemic inflammatory responses (interleukin-6 and tumor necrosis factor-alpha) during the postoperative time course were also determined. Data were analyzed using the Kruskal-Wallis test or univariate analysis of variance.

RESULTS

Body weight gain, food intake, liver and spleen weights, as well as LFTs [except aspartate aminotransferase (AST)] did not differ among the four groups. The significant increase in the AST level following laparoscopy compared to the anesthesia-only group was found on postoperative days 1 and 2; however, a similar difference was not detected after laparotomy or i.p. endotoxin injection. Laparoscopy showed no alterations in the hepatic glycogen stores compared to anesthesia only, whereas laparotomy and endotoxinemia significantly reduced the hepatic glycogen stores on postoperative days 2 and 4. The systemic postoperative inflammatory response did not differ between laparotomy and laparoscopy, but it was higher in both groups than in anesthesia only. In rats treated with endotoxin, the systemic inflammatory response was even higher than in the two surgical groups. The hepatic inflammatory response did not differ between the four groups.

CONCLUSION

This study shows a significant postoperative decrease in the hepatic glycogen content after laparotomy and i.p. endotoxin injection but not after laparoscopy. Food intake and inflammatory response cannot explain this difference between the two surgical groups, which suggests that alterations in the postsurgical hormonal stress response are the most likely explanation for these findings.

Early peritoneal macrophage function after laparoscopic surgery compared with laparotomy in a mouse mode

BACKGROUND

The authors previously demonstrated postoperative preservation of the immune function measured by delayed-type skin reaction and tumor growth after laparoscopic surgery, as compared with laparotomy. For further elucidation of the origin of the demonstrated immune preservation, peritoneal macrophage (PMo) function was investigated 1 h after different surgical procedures.

METHODS

Female NMRI mice were divided into five groups: anesthesia only, abdominal skin incision, laparotomy, peritoneal carbon dioxide (CO2) insufflation, and peritoneal air insufflation. Escherichia Coli phagocytosis, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta1 (TGF-beta1), and interleukin-10 (IL-10) release of isolated PMo were investigated.

RESULTS

All invasive interventions reduced the PMo phagocytosis by factors of approximately 2 to 4.7, as compared with the sham control group. Spontaneous ex vivo TNF-alpha release was significantly increased whenever the abdominal cavity was exposed to ambient air. The macrophage's ability to release TNF-alpha after E. coli exposure was diminished in the abdominal air exposure groups, as compared with the CO2 insufflation group.

CONCLUSION

Reduced phagocytosis 1 h after surgical interventions suggests a contribution of PMo to the altered immune function. When exposed to CO2, PMo show a decreased basal TNF-alpha release. However, PMo also show an increased TNF-alpha release after a second immune stimulation (E. coli), suggesting a greater competency of interaction in an immune defense reaction after CO2 exposure.

Carbon dioxide pneumoperitoneum–mediated attenuation of the inflammatory response is independent of systemic acidosis

BACKGROUND

The purpose of this study was to determine if systemic acidosis induced by peritoneal absorption of carbon dioxide (CO2 ) during laparoscopy plays a role in CO2 pneumoperitoneum-mediated attenuation of the acute phase inflammatory response associated with perioperative sepsis. The influence of hepatic polymorphonuclear (PMN) leukocyte infiltration on this phenomenon was also investigated.

METHODS

Forty-five rats were randomized into 5 groups: anesthesia control, open cecal ligation and puncture (OCLP), laparoscopic cecal ligation and puncture using helium for insufflation (He LCLP), LCLP using CO2 with continued spontaneous ventilation (LCLP-SV), and LCLP using CO2 with intubation and positive pressure ventilation (LCLP-PPV).

RESULTS

After 30 minutes, arterial blood gas parameters remained normal in control, OCLP rats, and He LCLP rats, while CO2 LCLP-SV rats developed significant hypercarbic acidosis. This acidosis was corrected in CO2 LCLP-PPV rats ( P < .0001 vs CO2 LCLP-SV for both). Expression of the rat acute phase gene alpha 2 -macroglobulin was greater after OCLP and He LCLP than after either CO2 LCLP-SV or CO2 LCLP-PPV ( P < .0001 vs either CO2 OCLP-SV for both). However, levels of alpha 2 -macroglobulin were not significantly different between the acidotic (LCLP-SV) and normocarbic (LCLP-PPV) CO2 groups. Infiltration of the hepatic parenchyma by PMNs did not differ significantly between groups.

CONCLUSIONS

CO2 insufflation-induced systemic acidosis is not responsible for the reduction in the acute phase inflammatory response observed in laparoscopic animal models of sepsis. Hepatic PMN infiltration also does not appear to mediate this effect.

Immunological advantages of advanced laparoscopy

Surgical trauma causes significant alterations in host immune function. Compared with open surgery, laparoscopic surgery is associated with reduced postoperative pain and more rapid return to normal activity. Experimental data have also shown more aggressive tumor establishment and growth rates following open surgery and laparoscopic surgery. Surgery-related immunosuppression may be partly responsible for the differences in cancer growth and outcome noted. It is clear that the choice of abdominal surgical approach has immunologic consequences. Further studies are needed to better the time course and extent of surgery-related alterations in the immune system and their clinical importance. A better understanding of the impact of surgery on the immune system may provide opportunities for pharmacologic manipulation of postoperative immune function to improve clinical results.

Videoendoscopic endotracheal intubation in the rat: A comprehensive rodent model of laparoscopic surgery1,2

BACKGROUND

Peritoneal absorption of CO(2) during abdominal insufflation in laparoscopy may disrupt the acid-base equilibrium and alter the physiological response to stress. Current nonventilated rodent models of laparoscopy do not manage the CO(2) load of pneumoperitoneum, but ventilated surgical rodent models are invasive (tracheotomy) and may independently induce the inflammatory response.

MATERIALS AND METHODS

A comprehensive rodent model of laparoscopy was developed. Rats were randomized to receive anesthesia alone, anesthesia plus CO(2) pneumoperitoneum, or anesthesia plus CO(2) pneumoperitoneum with videoendoscopic intubation and mechanical ventilation. Arterial blood-gas analysis was performed at baseline and after 30 min of intervention.

RESULTS

Baseline pH, pCO(2), and HCO(3)(-) arterial blood gas parameters were normal for all rats. After 30 min, pCO(2) and pH changed slightly but remained normal among rats receiving anesthesia alone (pCO(2) = 46.5 +/- 1.9; pH = 7.365 +/- 0.009) whereas animals receiving anesthesia plus CO(2) pneumoperitoneum that were dependent on spontaneous respiration for ventilation developed significant hypercarbic acidosis (pCO(2) = 53.2 +/- 1.9, P < 0.05; pH = 7.299 +/- 0.011, P < 0.001). This acidosis was completely corrected with increased minute ventilation in intubated rats receiving mechanical ventilation (pCO(2) = 36.8 +/- 1.5, P < 0.001; pH = 7.398 +/- 0.011, P < 0.001).

CONCLUSIONS

CO(2) pneumoperitoneum induces significant hypercarbic acidosis in nonventilated rats. Noninvasive endotracheal intubation is feasible in the rat with videoendoscopic assistance. Our noninvasive rodent model of laparoscopic surgery controls for anesthesia- and capnoperitoneum-related acid-base changes and provides an environment in which the biological response to pneumoperitoneum can be studied precisely.

Increased peritoneal dissemination after laparotomy versus pneumoperitoneum in a mouse cecal cancer model

BACKGROUND

The effect of carbon dioxide (CO(2)) pneumoperitoneum on the liberation of cancer cells from the primary tumor is not clear. This study investigated the influence of laparotomy versus CO(2) pneumoperitoneum on the progression of colon cancer with serosal invasion in a mouse model.

METHODS

Pieces of human colon adenocarcinoma (HT29) tumor were implanted in the cecal wall of 45 BALB/c nude mice. Each mouse underwent one of three procedures: laparotomy, CO(2) pneumoperitoneum, or anesthesia (control). Three weeks later, the size and weight of cecal tumors, the number of nodules, and the tumor volume score of peritoneal dissemination were examined. Another 45 mice were treated in the same way. The cecal tumor was resected on days 1, 3, or 5 after treatment. Total RNA was isolated from the resected tumors. The expression of E-cadherin and beta-1 integrin messenger RNA (mRNA) was examined by semiquantitative real-time reverse transcriptase-polymerase chain reaction assay.

RESULTS

Significantly more nodules of peritoneal dissemination were found in the laparotomy group than in the control group (p < 0.05). The tumor volume score of peritoneal dissemination in the laparotomy group was significantly higher than in the other two groups (p < 0.05). The expression of E-cadherin mRNA at day 5 in the laparotomy group was significantly less than in the other two groups (p < 0.05). There were no differences in beta-1 integrin among three groups.

CONCLUSIONS

Peritoneal dissemination was more extensive after laparotomy than after CO(2) pneumoperitoneum in a mouse model of cecal cancer with serosal invasion. Decreased expression of E-cadherin mRNA in tumors after laparotomy, but not after CO(2) pneumoperitoneum, may be associated with the increase in peritoneal dissemination.

The effect of timing of pneumoperitoneum on the inflammatory response

BACKGROUND

We examined the effects of an identical period of pneumoperitoneum applied at three different time points after lipopolysaccharide (LPS) challenge. Two different insufflation gases were also compared.

METHODS

Male rats (n = 70) were injected intravenously with 1 mg/kg of LPS (time 0). The time relationship between a 1.5-h period of insufflation and initial LPS stimulation was the experimental variable. All rats were killed 6 h after injection. CO2 and helium insufflation were investigated. Ten control rats received LPS only. Serum interleukin-6 (IL-6) levels were determined by enzyme-linked immunosorbent assay (ELISA). Hepatic expression of alpha2-macroglobulin, beta-fibrinogen, and metallothionein were measured by Northern blot analysis. Statistical analysis was performed using one-way analysis of variance (ANOVA).

RESULTS

Expression of alpha2-macroglobulin mRNA was lower in CO2 groups compared to the control group (p < 0.05 at time 120 and 270). beta-Fibrinogen message was diminished in CO2 0 and 120 groups compared to control. Serum levels of IL-6 and expression of metallothionein mRNA did not show significant differences between groups.

CONCLUSIONS

These findings suggest that CO2 pneumoperitoneum downregulates the inflammatory response to LPS challenge. Start time of CO2 insufflation does not appear to alter hepatic expression of acute phase genes. The mechanism of alpha2-macroglobulin downregulation does not appear to be due to IL-6.

The net immunologic advantage of laparoscopic surgery

The trauma of surgery evokes a variety of physiologic and immunologic alterations that should contribute to host defense. However, an exaggerated response to injury may result in immunosuppression and lead to significant postoperative morbidity and mortality. Laparoscopic surgery may result in less induced surgical trauma than conventional open surgery. Decreased postoperative pain and speedy functional recovery of laparoscopic patients may be attributable to the reduced inflammatory response and minimal immunosuppression. Inflammation, an early protective homeostatic immune response to injury, is characterized by the production of proinflammatory cytokines and by activation of cellular and humoral immune mechanisms. Postoperative levels of the inflammatory cytokines have been consistently lower after laparoscopic procedures, indicating a smaller degree of surgical insult and acute inflammatory reaction. Surgical stress derails the functions of both polymorphonuclear and mononuclear cells, which may lead to an increased risk of postoperative infection. Comparative studies of cellular immunity after laparoscopic and conventional surgery demonstrate immunologic advantage conferred by laparoscopy. Exaggerated activation of peritoneal immunity may lead to a relative local immunosuppression, resulting in ineffective intraperitoneal bacterial clearance and serious postoperative infections. Functions of the peritoneal macrophages are better preserved when laparotomy is avoided. Decreased perioperative stress may be particularly important for oncologic patients. Laparoscopic approaches may result in diminished perioperative tumor dissemination and better cancer outcomes. Although laparoscopy is "minimally invasive," systemic immune responses still are undeniably activated. However, laparoscopic surgery appears to induce a smaller injury, resulting in proportionally decreased immunologic changes. In addition to improved cosmesis and faster functional recovery, a patient undergoing laparoscopic surgery may benefit most from a net immunologic advantage.

New tools for laparoscopic division of the pancreas: a comparative animal study

We tested the hypothesis that the pancreas can be safely divided laparoscopically using non-suture devices. Twelve pigs were randomized into 4 groups: 1) laparoscopic distal pancreatectomy (LDP) using an ultrasonic scalpel; 2) LDP using an ultrasonic scalpel with pancreatic stump suture reinforcement; 3) LDP using a 35-mm laparoscopic linear vascular stapler; 4) LDP using a prototype 35-mm radio-frequency laparoscopic linear vascular stapler. There were no serious complications related to distal pancreatectomy. All groups gained weight by postoperative day (POD) 14. Serum amylase, glucose, electrolytes and total bilirubin levels were measured preoperatively and on POD 1, 3, 7, and 14, and peripancreatic peritoneal fluid amylase levels were measured on POD 7 and 14; all remained normal in all groups. Fewer adhesions to the pancreatic stump were found in the ultrasonic scalpel groups as compared with the stapler groups. Ultrasonic dissection may be the superior means oflaparoscopic transection of the pancreas.

Evaluation of laparoscopic-assisted placement of jejunostomy feeding tubes in dogs

OBJECTIVE

To evaluate feasibility of performing laparoscopic-assisted placement of a jejunostomy feeding tube (J-tube) and compare complications associated with placement, short-term feedings, and medium-term healing with surgically placed tubes in dogs.

DESIGN

Prospective study.

ANIMALS

15 healthy mixed-breed dogs.

PROCEDURES

Dogs were randomly allocated to undergo open surgical or laparoscopic-assisted J-tube placement. Required nutrients were administered by a combination of enteric and oral feeding while monitoring for complications. Radiographic contrast studies documented tube direction and location, altered motility, or evidence of stricture.

RESULTS

Jejunostomy tubes were successfully placed in the correct location and direction in all dogs. In the laparoscopic group, the ileum was initially selected in 2 dogs, 2 dogs developed moderate hemorrhage at a portal site, and 2 J-tubes kinked during placement but were successfully readjusted postoperatively. All dogs tolerated postoperative feedings. All dogs developed minor ostomy site inflammation, and 1 dog developed bile-induced dermatitis at the ostomy site. Despite mild, transient neutrophilia, no significant difference was noted in WBC counts between groups. No dog had altered gastric motility or evidence of stricture, although the jejunopexy site remained identifiable in several dogs at 30 days.

CONCLUSIONS AND CLINICAL RELEVANCE

Requirements for successful J-tube placement were met by use of a laparoscopic-assisted technique, and postoperative complications were mild and comparable to those seen with surgical placement. Laparoscopic-assisted J-tube placement compares favorably to surgical placement in healthy dogs and should be considered as an option for dogs requiring enterostomy feeding but not requiring a celiotomy for other reasons.