Selective Opioid Antagonists Following Bowel Resection for Prevention of Postoperative Ileus: a Systematic Review and Meta-analysis

BACKGROUND

Postoperative ileus (POI) remains a common complication following bowel resection. Selective opioid antagonists have been increasingly studied as prophylactic pharmaceutical aids to reduce rates of POI. The aim of this study was to evaluate the impact of selective opioid antagonists on return of bowel function following bowel resection.

METHODS

MEDLINE, Embase, and CENTRAL were systematically searched. Articles were included if they compared the incidence of POI and/or length of stay (LOS) in patients receiving and not receiving selective opioid antagonists following elective bowel resection. A pairwise meta-analyses using inverse variance random effects was performed.

RESULTS

From 636 citations, 30 studies with 45,051 patients receiving selective opioid antagonists (51.3% female, mean age: 60.9) and 55,071 patients not receiving selective opioid antagonists (51.2% female, mean age: 61.1) were included. Patients receiving selective opioid antagonists had a significantly lower rate of POI (10.1% vs. 13.8%, RR 0.68, 95%CI 0.63-0.75, p < 0.01). Selective opioid antagonists also significantly reduced LOS (MD - 1.08, 95%CI - 1.47 to - 0.69, p < 0.01), readmission (RR 0.94, 95%CI 0.89-0.99, p = 0.03), and 30-day morbidity (RR 0.85, 95%CI 0.79-0.90, p < 0.01). Improvements in LOS, readmission rate, and morbidity were not significant when analysis was limited to laparoscopic surgery. There was no significant difference in inpatient healthcare costs (SMD - 0.33, 95%CI - 0.71-0.04, p = 0.08).

CONCLUSIONS

Rate of POI decreases with the use of selective opioid antagonists in patients undergoing bowel resection. Selective opioid antagonists also improve LOS, rates of readmission, and 30-day morbidity for patients undergoing open bowel resection. Addition of these medications to enhance recovery after surgery protocols should be considered.

The association of alvimopan treatment with postoperative outcomes after abdominal surgery: A systematic review across different surgical procedures and contexts of perioperative care

BACKGROUND

Alvimopan is a Food and Drug Administration-approved treatment to accelerate gastrointestinal recovery after abdominal surgery; however, benefits may vary across different procedures and contexts of care. The purpose of this study is to summarize the evidence regarding the effect of alvimopan on postoperative outcomes after abdominal surgery.

METHODS

Major databases (Medline, Embase, Biosis, Cochrane, Web of Science, and Scopus) were searched for randomized controlled trials and nonrandomized studies comparing alvimopan versus control. Risk of bias was assessed using Cochrane's risk of bias tool 2.0 (for randomized controlled trials) and Risk of Bias in Nonrandomized Studies-of Intervention tool (for nonrandomized studies). Results were appraised descriptively as heterogeneity in reporting and risk of bias hindered meta-analysis. Quality of evidence across different surgical procedures and contexts of care (ie, open versus minimally invasive surgery, traditional care versus enhanced recovery pathway) was evaluated using Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

Nine randomized controlled trials and 35 nonrandomized studies were identified. Evidence of low to moderate certainty supports that alvimopan reduces length of stay and improves gastrointestinal recovery after open bowel resection and open radical cystectomy. Limited evidence supports alvimopan for surgeries not listed in Food and Drug Administration labels (ie, total abdominal hysterectomy and retroperitoneal lymph node dissection). Similar effects were observed in traditional and enhanced recovery pathway settings, but enhanced recovery pathway elements varied across studies. There is very low certainty of evidence supporting alvimopan for patients undergoing minimally invasive surgery.

CONCLUSION

Evidence supports that alvimopan improves outcomes after open bowel resection and open radical cystectomy. Benefits for patients undergoing minimally invasive surgery and treated in contemporary enhanced recovery pathway settings remain uncertain. These findings contribute important new knowledge to inform evidence-based alvimopan prescribing.

Acute Colonic Pseudo-Obstruction After Posterior Spinal Fusion: A Case Report and Literature Review

BACKGROUND

Acute colonic pseudo-obstruction (ACPO) or Ogilvie's syndrome occurs in 0.22%-7% of patients undergoing surgery, with a mortality of up to 46%. ACPO increased median hospital days versus control in spinal surgery (14 vs. 6 days; P < 0.001). If defined as postoperative ileus, the incidence was 7%-13.4%. Postoperative ileus is associated with 2.9 additional hospital days and an $80,000 increase in cost per patient. We present a case of ACPO in an adult patient undergoing spinal fusion for correction of scoliosis and review the available literature to outline clinical characteristics and surgical outcomes.

CASE DESCRIPTION

The patient was a 31-year-old woman with untreated advanced scoliosis with no history of neurologic issues. T2-L3 spinal instrumentation and fusion was completed. Plain abdominal radiography showed of dilated cecum 11 cm and the department of general surgery was consulted. Neostigmine administration was planned after conservative treatment failure after transfer to the intensive care unit. The patient was discharged home with no recurrence >60 days. Thirty cases were found in our literature review using PubMed and Embase databases and summarized.

CONCLUSIONS

Of 30 cases reviewed, only 3 cases of ACPO were specific to patients undergoing spinal fusion for scoliosis. According to the literature, 20% of patients had resolution with conservative treatment, 40% with neostigmine, and 30% with surgical intervention. Other noninvasive treatments may have similar efficacy in preventing complications leading to surgical invention. Sixty clinical trials and 9 systematic reviews were summarized with an updated management algorithm.

Enhanced Recovery Pathway for Right and Left Colectomy: Comparison of Functional Recovery

BACKGROUND

Enhanced recovery (ERAS) guidelines do not differentiate between left- and right-sided colectomies, but differences in recovery have been reported for the two procedure types. We aimed to compare compliance with the ERAS protocol and outcomes after right versus left colectomy.

METHODS

Between June 2011 and September 2014, all patients undergoing elective colonic resection were treated according to a standardized ERAS protocol and entered a prospective database. This retrospective analysis compared right and left colectomy regarding application of the ERAS pathway, bowel recovery, complications, and hospital stay.

RESULTS

Eighty-five patients with right colectomy matched well with 138 left-sided resections for baseline demographics. Overall compliance with the ERAS protocol was 76 % for right versus 77 % for left colectomy patients (p = 0.492). First flatus occurred at postoperative day 2 in both groups (p = 0.057); first stool was observed after a median of 3 (right) and 2 days (left), respectively (p = 0.189). Twenty patients (24 %) needed postoperative nasogastric tube after right colectomy compared to 11 patients (8 %) after left colectomy (p = 0.002). Overall complication rates were 49 and 37 % for right and left colectomy, respectively (p = 0.071). Median postoperative length of stay was 6 days (IQR 4-9) after right and 5 days (IQR 4-7.5) after left colectomy (p = 0.020).

CONCLUSION

Overall compliance with the protocol was equally high in both groups showing that ERAS protocol was applicable for right and left colectomy. Functional recovery however, tended to be slower after right colectomy, and postoperative ileus rate was significantly higher. More cautious early feeding after right colectomy should be considered.

Alvimopan combined with enhanced recovery strategy for managing postoperative ileus after open abdominal surgery: a systematic review and meta-analysis

BACKGROUND

To assess the efficacy and safety of alvimopan in conjunction with enhanced recovery strategy, compared with this strategy alone, in management of postoperative ileus in patients undergoing open abdominal surgery.

METHODS

Electronic databases were comprehensively searched for relevant randomized controlled trials. We were interested in doses of 6 and 12 mg. The efficacy end points included the time to recovery of full gastrointestinal (GI) function (a composite end point measured by the time to first toleration of solid food [SF] and the time to first passage of stool, GI-2), the recovery of upper (SF) or the lower (the time to first bowel movement, BM) GI function, and the length of hospital stay (the time to discharge order written). Safety end points included GI-related, non-GI-related, and serious adverse events. These parameters were all analyzed by RevMan 5.3 software.

RESULTS

Nine randomized controlled trials involving 4075 patients were enrolled in this study. The pooled results showed that alvimopan significantly decreased the time to GI-2 recovery (6 mg, hazard ratio [HR] = 1.45, P < 0.00001; 12 mg, HR = 1.59, P < 0.00001), BM (6 mg, HR = 1.54, P < 0.00001; 12 mg, HR = 1.74, P = 0.0002), and the time to discharge order written (6 mg, HR = 1.37, P < 0.00001; 12 mg, HR = 1.34, P < 0.00001) compared with the placebo group. However, SF was significantly reduced in 6 mg group (HR = 1.23, P = 0.008) rather than 12 mg group (HR = 1.14, 95% confidence interval 1.00, 1.30, P = 0.04). The incidence of some GI-related and serious adverse events were significantly lower in the alvimopan group than the placebo group, and the dose of 12 mg was superior to 6 mg in this regard.

CONCLUSIONS

Alvimopan can accelerate recovery of GI function (especially for the lower GI tract), shorten the length of hospital stay, and reduce postoperative ileus-related morbidity without compromising opioid analgesia in an enhanced recovery setting.

Incidence of prolonged postoperative ileus after colorectal surgery: a systematic review and meta-analysis

AIM

Prolonged postoperative ileus (PPOI) after colorectal surgery remains a leading cause of delayed postoperative recovery and prolonged hospital stay. Its exact incidence is unknown. The aim of this systematic review is to investigate the definitions and incidence of PPOI previously described.

METHOD

MEDLINE, Embase and the Cochrane Database of Systematic Reviews (up to July 2014) were searched. Two authors independently reviewed citations using predefined inclusion and exclusion criteria.

RESULTS

The search strategy yielded 3233 citations; 54 were eligible, comprising 18 983 patients. Twenty-six studies were prospective [17 of these being randomized controlled trials (RCTs)] and 28 were retrospective. Meta-analysis revealed an incidence of PPOI of 10.3% (95% CI 8.4-12.5) and 10.2% (95% CI 5.6-17.8) for non-RCTs and RCTs, respectively. Significant heterogeneity was observed for both non-RCTs and for RCTs. The used definition of PPOI, the type of surgery and access (laparoscopic, open) and the duration of surgery lead to significant variability of reported PPOI incidence between studies. The incidence of PPOI is lower after laparoscopic colonic resection.

CONCLUSION

There is a large variation in the reported incidence of PPOI. A uniform definition of PPOI is needed to allow meaningful inter-study comparisons and to evaluate strategies to prevent PPOI.

Methylnaltrexone for the treatment of opioid-induced constipation

Opioids are the drugs of choice for treating moderate-to-severe pain, especially for patients in the end stage of cancer or other advanced illnesses, and also in critical care or for the treatment of chronic pain. Side effects such as nausea, pruritus, dizziness and constipation have to be controlled in order to use these drugs to their full potential. Opioid-induced bowel syndrome and constipation caused by activation of μ-receptors in the gut can have such distressing effects that some patients prefer to forego adequate pain control. Methylnaltrexone is a μ-opioid receptor antagonist that, unlike naltrexone or naloxone, does not pass the blood-brain barrier, and therefore does not impair the centrally mediated analgesic effect of opioids. It is licensed for the treatment of opioid-induced constipation in palliative care in more than 50 countries. This article presents practically relevant pharmacological data, basic research results and evidence from clinical research about methylnaltrexone, and outlines potential future therapeutic options for this promising drug.

New therapeutic strategies for postoperative ileus

Patients undergoing an abdominal surgical procedure develop a transient episode of impaired gastrointestinal motility or postoperative ileus. Importantly, postoperative ileus is a major determinant of recovery after intestinal surgery and leads to increased morbidity and prolonged hospitalization, which is a great economic burden to health-care systems. Although a variety of strategies reduce postoperative ileus, including multimodal postoperative rehabilitation (fast-track care) and minimally invasive surgery, none of these methods have been completely successful in shortening the duration of postoperative ileus. The aetiology of postoperative ileus is multifactorial, but insights into the pathogenesis of postoperative ileus have identified intestinal inflammation, triggered by surgical handling, as the main mechanism. The importance of this inflammatory response in postoperative ileus is underscored by the beneficial effect of pharmacological interventions that block the influx of leukocytes. New insights into the pathophysiology of postoperative ileus and the involvement of the innate and the adaptive (T-helper type 1 cell-mediated immune response) immune system offer interesting and important new approaches to prevent postoperative ileus. In this Review, we discuss the latest insights into the mechanisms behind postoperative ileus and highlight new strategies to intervene in the postoperative inflammatory cascade.