Metabolism and immunology in laparoscopy. First workshop on experimental laparoscopic surgery, Frankfurt, 1997

Improved abdominal wall wound healing by helium pneumoperitoneum

BACKGROUND

Despite widespread use of the endoscopic technique in the treatment of inguinal and incisional hernias, knowledge about its impact on abdominal wall wound healing is rare. Questions remain regarding the risk of port-site hernias and hernia recurrence. The current study investigated the gas-dependent effects of pneumoperitoneum on laparotomy wound healing.

METHODS

Laparotomy was performed in 54 male Sprague-Dawley rats. A carbon dioxide (n = 18) or helium (n = 18) pneumoperitoneum of 3 mmHg was maintained before and after laparotomy, with an overall duration of 30 min. The rats in the control group (n = 18) received no pneumoperitoneum. The animals were killed after 5 and 10 days, and the abdominal wall was explanted for subsequent histopathologic examinations of the laparotomy wound. The granuloma formation in hematoxylin and eosin-stained sections was analyzed. Infiltration of macrophages (CD68) and expression of matrix metalloproteinases (MMP-8 and MMP-13) were examined by immunohistochemistry. The collagen type 1 to type 3 ratio was investigated by cross-polarization microscopy after Sirius Red staining.

RESULTS

After 5 and 10 days, the percentages of CD68-positive cells, granuloma formation, and expression of MMP-8 did not differ between the groups. In contrast, after both 5 and 10 days, the expression of MMP-13 and the collagen 1 to 3 ratio were significantly higher after helium pneumoperitoneum than in the control animals.

CONCLUSION

The results suggest that helium pneumoperitoneum may ameliorate wound healing within the abdominal wall and could therefore represent a beneficial gas for endoscopic hernia repair.

Signs of reperfusion injury following CO2 pneumoperitoneum: an in vivo microscopy study

BACKGROUND

During laparoscopic surgery, pneumoperitoneum is generally established by means of carbon dioxide (CO(2)) insufflation which may disturb hepatic microperfusion. It has been suggested that the desufflation at the end of the procedure creates a model of reperfusion in a previously ischemic liver, thus predisposing it to reperfusion injury.

METHODS

To study the effects of pneumoperitoneum on hepatic microcirculation, Sprague-Dawley rats underwent pneumoperitoneum with an intraabdominal pressure of 8 or 12 mmHg for 90 min. Subsequently, in vivo microscopy was performed to assess intrahepatic microcirculation and transaminases were measured to index liver injury.

RESULTS

A CO(2) pneumoperitoneum of 8 mmHg did not change serum transaminases; however, further increase of intraperitoneal pressure to 12 mmHg significantly increased AST, ALT, and LDH measured after desufflation to almost 1.5 times as much as control values of 49 +/- 5 U/L, 31 +/- 3 U/L, and 114 +/- 12 U/L. In parallel, in all subacinar zones the permanent adherence of both leukocytes and platelets to the endothelium increased by about sixfold and threefold, respectively. Furthermore, Kupffer cells labeled with latex beads as an index for their activation were significantly increased compared to controls.

CONCLUSION

This in vivo observation demonstrated traces of reperfusion injury in liver induced by the insufflation and desufflation of CO(2 )pneumoperitoneum. The clinical relevance of this finding and the issue of using hepatoprotective substances to prevent this injury should be further investigated.

Laparoscopy and collagen metabolism

The collagens represent a vital component within the wound healing process and physiological scar formation. Therefore, analysing the influence of new operative procedures on collagen metabolism is of great surgical interest. As the endoscopic technique has, nowadays, become routinely applied for diverse abdominal diseases worldwide, we present a review of literature facing its impact on collagen biology.

Effect of laparoscopy on immune function

BACKGROUND

Laparoscopic surgery is believed to lessen surgical trauma and so cause less disturbance of immune function. This may contribute to the rapid recovery noted after many laparoscopic operations. Preservation of both systemic and intraperitoneal immunity is particularly important in surgery for sepsis or cancer and so an understanding of the impact of laparoscopy on immune function is relevant.

METHODS

Literature on immunological changes following laparoscopy and open surgery was identified from Medline, along with cross-referencing from the reference lists of major articles on the subject.

RESULTS AND DISCUSSION

Despite a few contradictory reports, systemic immunity appears to be better preserved after laparoscopic surgery than after open surgery. However, the local intraperitoneal immune system behaves in a particular way when exposed to carbon dioxide pneumoperitoneum; suppression of intraperitoneal cell-mediated immunity has been demonstrated in a number of studies. This feature may be clinically important and should be acknowledged when considering laparoscopic surgery in patients with malignancy or sepsis.

Effect of insufflation gas and intraabdominal pressure on portal venous flow during pneumoperitoneum in the rat

BACKGROUND

Carbon dioxide, the primary gas used to establish a pneumoperitoneum, causes numerous systemic effects related to cardiovascular function and acid-base balance. Therefore, the use of other gases, such as helium, has been proposed. Furthermore, the pneumoperitoneum itself, with the concomitant elevation of intraabdominal pressure, causes local and systemic effects that have been only partly elucidated. Portal blood flow, which plays an important role in hepatic function and cell-conveyed immune response, is one of the affected parameters.

METHODS

An established animal model (rat) of laparoscopic surgery was extended by implanting a periportal flow probe. Hemodynamics in the portal vein were then measured by transit-time ultrasonic flowmetry during increasing intraabdominal pressure (2-12 mmHg) caused by gas insufflation (carbon dioxide vs helium).

RESULTS

The installation of the pneumoperitoneum with increasing intraperitoneal pressure led to a significant linear decrease in portal venous flow for both carbon dioxide and helium. At higher pressure levels (8-12 mmHg), portal blood flow was significantly lower (1.5-2.5-fold) during carbon dioxide pneumoperitoneum. An intraabdominal pressure of 8 mmHg caused a decrease to 38.2% of the initial flow (helium, 59.7%); whereas at 12 mmHg, portal flow was decreased to 16% (helium, 40.5%).

CONCLUSION

Elevated intraabdominal pressure generated by the pneumoperitoneum results in a reduction of portal venous flow. This effect is significantly stronger during carbon dioxide insufflation. Portal flow reduction may compromise hepatic function and cell-conveyed immune response during laparoscopic surgery.

Laparoscopic surgery and surgical infection

INTRODUCTION

It has been observed that the metabolic response to surgical injury is less after laparoscopic surgery than after open surgery. However, the effect of laparoscopic surgery on surgical infection has not been given much attention in the surgical literature, even though it may decrease the incidence of infectious complications. The objective of this study was to assess the influence that laparoscopic surgery has on surgical infection and to highlight certain controversial aspects.

METHODS

A review of the literature was undertaken to examine the relationship between laparoscopic surgery and surgical infection. This was achieved primarily by using PubMed Medline as a source of material.

RESULTS AND CONCLUSION

Laparoscopic surgery is associated with better preservation of the immune system than open surgery. This results in a decreased incidence of infectious complications. Although carbon dioxide pneumoperitoneum affects the peritoneal response to injury, it seems to have no harmful effect in terms of intra-abdominal infection. Nevertheless, at laparoscopic operation the virulence of intestinal micro-organisms should be recognized and, while knowing the advantages of minimally invasive surgery, the surgeon should consider the complexity of this technique. Furthermore, maintenance of laparoscopic instruments should be governed by the same norms as those used in open surgery; recommendations offered by the manufacturers should be respected.

Could age be an indication for laparoscopic colectomy in colorectal cancer?

BACKGROUND

The incidence of colorectal carcinoma increases in the elderly. Regardless of age as an isolated factor, postoperative complications represent the main factor in increasing hospital mortality.

METHODS

The aim of this study was to compare the short-term results (first 30 postoperative days) after laparoscopically assisted colectomy (LAC) and open segmental colectomy (OC) in colorectal carcinoma between two groups of patients, older than 70 and younger than 70 years of age. In the study from November 1993 to June 1998, 255 patients were evaluated to participate.

RESULTS

Peristalsis, oral intake, and discharge from the hospital occurred earlier in LAC than in OC treated patients, in the two age groups. The mean operative time was significantly longer in the LAC than in the OC patients in the two age groups. No differences were observed in morbidity between LAC and OC in the group younger than 70 years of age. However, the overall morbidity was significantly lower in the LAC group in patients older than 70 years. One patient in the LAC group older than 70 years died.

CONCLUSION

These results suggest that laparoscopically assisted colectomy may be particularly indicated in elderly patients.

Effects of intraabdominally insufflated carbon dioxide and elevated intraabdominal pressure on postoperative gastrointestinal transit: an experimental study in mice

BACKGROUND/PURPOSE

Postoperative ileus after abdominal operations is thought to be related to the degree of surgical trauma, and it has been shown that the simple act of opening the peritoneum can decrease gastrointestinal motility. Accordingly, some investigators have shown a reduction in the duration of postoperative ileus after laparoscopic procedures. It is not clear, however, if this reduction is secondary to less manipulation of the viscera or to the lack of an abdominal incision. The aim of this study was to determine the effect of intraabdominal insufflation with CO2 on postoperative gastrointestinal transit.

METHODS

Twenty-eight male mice weighing between 25 and 30 g were divided randomly into 4 groups: Control (unoperated), Incision (conventional laparotomy), Cecal (laparotomy plus cecal manipulation), and Insufflation (abdominal insufflation with CO2). Postoperative gastrointestinal motility was assessed by weighing total fecal output over the first 15 postoperative hours.

RESULTS

Fecal pellet output over 15 hours in the untreated control group was 1.20 +/- 0.12 g. In mice subjected to peritoneal incision alone, fecal pellet output was significantly decreased to 0.82 +/- 0.11 g (P < .05). However, in mice subjected to abdominal insufflation with CO2, fecal pellet output was not significantly different from untreated controls (1.2 +/- 0.05 g; not significant). Fecal pellet output was markedly reduced by incision combined with cecal manipulation (0.24 +/- 0.02 g, P < .01).

CONCLUSIONS

The current study findings show that abdominal insufflation, in a procedure similar to that used during laparoscopic surgery, had no measurable effect on gastrointestinal transit in awake mice. This suggests that the lack of an abdominal incision can contribute to a reduced postoperative ileus after abdominal surgery.

Minimally invasive techniques for colorectal cancer

Laparoscopic approaches are increasingly being applied to colorectal surgical procedures. Initial concerns regarding the existence of benefits from the laparoscopic approach have now been addressed. Even as these were being addressed, however, further concerns arose regarding the appropriateness of this technique in malignancy. Colorectal cancer is the only intra-abdominal malignancy that is knowingly resected employing laparoscopic techniques. This controversy was highlighted by reports of early wound implants. With careful technique, training and experience, however, wound recurrences are rarely seen, suggesting that this phenomenon, in the clinical setting, is primarily technique-related. Lack of rigorous evidence either condemning or supporting the laparoscopic approach for colorectal cancer resulted in the establishment of several large-scale randomized, prospective trials, all currently in progress, that aim to determine if laparoscopic resection of colorectal cancer results in oncologic outcomes comparable to the open approach.