Does Laparoscopic Omentectomy Reduce CAPD Catheter Malfunction: A Three-arm Pilot Randomized Trial

Introduction

Continuous ambulatory peritoneal dialysis (CAPD) is an effective method of renal replacement therapy that helps preserve residual renal function in patients with end-stage renal disease (ESRD).[1] A properly positioned and patent dialysis catheter is paramount to successful CAPD. Various methods of insertion of CAPD catheter are in practice, namely, percutaneous, peritoneoscopic, laparoscopic, and open techniques.[2] Open surgical insertion under local anesthesia is the most commonly performed procedure. However, the open technique has certain disadvantages as it involves blind placement of the catheter, which may pose difficulty, especially in patients with obesity, previous laparotomy, or peritoneal adhesions. In comparison, laparoscopic technique allows accurate siting of the catheter in the pelvis under direct vision, and thus, may have less risk of catheter migration. However, laparoscopy requires general anesthesia, which carries its own risk, especially in patients with ESRD. Randomized studies comparing laparoscopic and open peritoneal dialysis (PD) catheter insertion (PDCI) have not shown any advantage of the former in terms of catheter survival.[34] A possible explanation could be that even with the laparoscopic technique, catheter malfunction is a frequent complication because of omental wrapping.

Prevention of omental wrapping by performing prophylactic omentectomy has been hypothesized and attempted in some centers.[56] However, performing omentectomy by open technique entails need for a long incision and can become a morbid surgery in patients with ESRD. Laparoscopic omentectomy is feasible and safe in experienced hands. Laparoscopy not only allows precise positioning of catheter under direct vision but also makes omentectomy easy and less morbid. This pilot randomized controlled trial (RCT) was undertaken to evaluate whether laparoscopic PDCI with or without omentectomy reduces the incidence of PD catheter malfunction.

Materials and Methods

This three-armed, parallel, pilot RCT was conducted at a tertiary referral center in northern India, after obtaining due clearance from the Institute Ethics Committee. The study was conducted jointly by the general surgery and nephrology departments. Informed written consent was taken from all patients.

Results

Between September 2017 and September 2019, 59 consecutive patients, eligible for CAPD, were assessed. Fourteen patients were excluded for various reasons, and the remaining 45 were randomly allocated to Group A (n = 18), Group B (n = 12), and Group C (n = 15). Two patients in Group A discontinued PD, one in Group B was lost to follow-up, and one patient in Group C died 3 weeks after catheter insertion. In ITT analysis, these four patients were considered to have had catheter malfunction at both 6 weeks and 3 months. Per-protocol analysis was done excluding these four patients, with 16, 11, and 14 patients in Groups A, B, and C, respectively [Figure 1].

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Figure 1

CONSORT (Consolidated Standards of Reporting Trials) diagram

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Baseline demographic and clinical characteristics of the study population are shown in Table 1. The mean age of the patients was 50.5 ± 21.3 years (range 4–82) and mean body mass index (BMI) was 23.2 ± 5.3 kg/m² (range 13.9–34.6). The percentage of male patients was higher in Group C, but the difference was not significant. The known duration of chronic kidney disease was significantly higher in Group B (P = 0.02).

Discussion

This pilot trial is the first randomized study attempting to evaluate the role of laparoscopic omentectomy on PD catheter function. Follow-up at 3 months was more than 90%, and all the patients underwent the treatment that was allocated; there was no crossover. Only one out of 16 patients undergoing omentectomy had catheter malfunction, which, on re-laparoscopy, was found to be due to small bowel adhesions. Although the difference in catheter malfunction among patients with and without omentectomy did not reach statistical significance, the reduction in malfunction in the former was clinically relevant.

One of the most frequent complications of PD is catheter malfunction due to mechanical obstruction secondary to omental wrapping, kinking, or migration of the catheter. Proponents of laparoscopy claim that catheter insertion under vision results in a higher success rate due to accurate placement of the tip of the catheter in the pelvis. However, two meta-analyses comparing laparoscopic and open PDCI reported contradictory results. Xie et al.,[7] in a meta-analysis of four randomized trials and 10 observational studies, found longer operating time in laparoscopic PDCI and no difference in hospital stay, early and late complications, including catheter migration and blockage. In another meta-analysis of three randomized trials and eight cohort studies, Hagen et al.[8] found a lesser incidence of catheter migration and greater 1-year catheter survival in the laparoscopic approach. In a recent multicenter randomized trial comparing laparoscopic and open PDCI (CAPD I trial), van Laanen et al.[3] compared catheter function 2 to 4 weeks after insertion. Adequate function was seen in 77% of patients having open insertion and 70% of patients having laparoscopic insertion. The difference was statistically not significant, and morbidity in the two groups was comparable. The authors commented that laparoscopy-assisted catheter fixation and omentectomy might improve catheter survival. The CAPD II trial is currently underway to study this objective. In another randomized trial from the United Kingdom, Wright et al.[4] found conventional surgery to be significantly faster than laparoscopic surgery. Catheter survival and early and late complications were comparable. Our results were similar, with the incidence of catheter malfunction at 3 months being 36.4% and 21.4%, respectively, for laparoscopic (without omentectomy) and open techniques. In a randomized trial of first-time PDCI from Taiwan, 77 patients were randomly allocated to open or laparoscopic insertion. Catheter longevity was comparable in the two arms. The authors recommended conventional open insertion for patients having primary catheter placement, as it was more cost-effective.[9] Similarly, in patients undergoing PDCI for the first time, we did not find any advantage of a laparoscopic approach. However, when performing omentectomy, laparoscopy is the preferred approach as it allows removal of the omentum through 1- to 2-cm incisions, which otherwise would require a long incision, resulting in increased morbidity.

Several authors have proposed partial omentectomy to reduce the incidence of catheter malfunction due to omental wrapping. Omentum has a natural tendency to wrap around any foreign body in the peritoneal cavity and isolate it from the rest of the abdomen. Omental wrapping around the catheter causes occlusion of the side holes or tip of the catheter, which is clinically manifested as outflow obstruction.[10] Reissman et al.[5] performed routine omentectomy in 60 consecutive patients under local anesthesia. There was only one (2%) catheter obstruction during a mean follow-up of 28 months and 90% of the catheters survived 1 year. Nicholson et al.[6] performed omentectomy in 113 cases out of 300 consecutive open PD catheter insertions. Catheter survival was significantly higher in the patients having omentectomy (78%, compared with 50% without omentectomy, P = 0.0002). In a retrospective study by Kavalakkat et al.,[11] 40 patients underwent omentectomy and PDCI, whereas 18 underwent PDCI only. None of the patients undergoing omentectomy developed catheter blockage, whereas 27.8% of patients in the other group did. In a study by Sanderson et al.,[12] routine omentectomy in 260 patients undergoing CAPD catheter placement resulted in 60% reduction in catheter obstruction. One-year catheter survival was 90%. In our study, omentectomy resulted in a malfunction rate of 6.2% at 3 months, compared with 28% without omentectomy. Our results, though statistically not significant, are in concordance with these studies.

Although prophylactic omentectomy during open PDCI has shown promising results in terms of catheter survival, there is no large series of laparoscopic prophylactic omentectomy. Laparoscopic insertion and omentectomy are more often recommended as a salvage procedure for blocked PD catheters.[10131415] A purported advantage of laparoscopic PDCI (in addition to facilitating omentectomy through small incisions) is that it also facilitates lysis of intraperitoneal adhesions. Patients who have had previous abdominal surgery or PD peritonitis are more prone to adhesion formation. In the open technique of PDCI, it is difficult to lyse these adhesions without resorting to a long incision, with its attendant morbidity. Patients with previous failed PD catheter comprised a major fraction (53%, n = 24/45) of our study population. These patients either had removal of their previous catheter due to intractable or fungal peritonitis, or came with a catheter in situ, with outflow failure. Laparoscopic insertion and/or omentectomy in such situations may be advantageous. Yilmazlar et al.[14] reported 16 cases of malfunctioning catheter, of which 13 were salvaged using adhesiolysis (n = 8) or catheter repositioning (n = 5). Peppelenbosch et al.[15] successfully managed 18 out of 23 patients with catheter malfunction using a combination of advanced laparoscopic techniques, including catheter repositioning (n = 23), fixation (n = 21), omentectomy (n = 8), and adhesiolysis (n = 3). Lee and Donovan[13] performed omentectomy in 13 patients with catheter malfunction; five patients had recurrent catheter malfunction, of which three were managed with laparoscopic manipulation. In our study, the previous catheter was salvaged in eight patients, of which six underwent omentectomy and two had simple laparoscopic repositioning without omentectomy. In patients with previous failed PDCI, omentectomy led to a fivefold reduction (8.3% vs. 45.5% in no omentectomy) in malfunction at 3 months. Thus, laparoscopic omentectomy seems to be beneficial in this subset of patients.

Important disadvantages of the laparoscopic technique are the need for general anesthesia with its attendant risks, prolonged operating time, and the need for expensive laparoscopic setup and instruments. In a recent Indian study, in which 19 patients with malfunctioning catheters underwent laparoscopic salvage procedure with omentopexy, the median operating time was 63 minutes, and there were no intraoperative or postoperative complications.[16] In the study by Kavalakkat et al.,[11] operating time was significantly higher in patients who had omentectomy (90 minutes vs. 80 minutes in patients without omentectomy). Similar results were observed in our study; on an average, omentectomy took about 26 minutes more. However, the low rate of intraoperative complications (6.2%, n = 1/16) in our study confirms that laparoscopic PDCI with omentectomy is a safe procedure. In a recent multicenter collaborative cohort study from USA, the incidence of early PD peritonitis (defined as peritonitis within 60 days of insertion of a catheter) was 8.4%.[17] The incidence of early PD peritonitis (within 3 months) in our study was also relatively low (4.9%) and comparable among the three groups. This is in contrast to a recent Turkish study, in which the authors found a significant higher rate of peritonitis in open insertion (75%) compared with laparoscopic insertion (25%). The high rate of peritonitis in this study is not surprising, as this was a 12-year-long study with longer follow-up.[18]

Our study is limited by inadequate sample size and short follow-up. Block randomization was not done, leading to unequal distribution of patients in the three groups. The high proportion of patients with prior failed PD catheter is also a shortcoming, as these patients may be more likely to benefit from laparoscopic omentectomy. Despite these limitations, the results of our study may be clinically relevant. We chose to conduct a pilot trial as the majority of ESRD patients in our setup are reluctant to opt for PD and prefer hemodialysis as renal replacement therapy. PD. Future research should also be focused on cost–benefit analysis of surgical PD catheter insertion techniques in the Indian setting.

In conclusion, this study found a statistically nonsignificant but clinically relevant reduction of catheter malfunction in patients undergoing laparoscopic omentectomy, especially in those with previous failed PD catheters. High-quality trials with adequate number of patients are required before this can be routinely practiced.