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Colorectal operations are among the most frequently performed major abdominal surgical procedures1, 2. Postoperative pain requiring bed rest and persistent gastrointestinal dysfunction are key factors keeping the patient in hospital. Although systemic opioids are effective for pain, they delay recovery of colonic mobility and prolong postoperative ileus3. For more than 20 years epidural analgesia (EA) has been advocated as improving pain control4, and it has been demonstrated to decrease the duration of ileus and postoperative complications in some studies5. EA is currently considered as playing a key role in postoperative management after colorectal surgery6, 7 but studies have failed to demonstrate that it reduces hospital stay8, 9, and it may even increase the cost of postoperative pain management and be responsible for rare but devastating complications, such as epidural haematoma and abscess10, 11. In the light of the above, a systematic review of the literature was performed to assess the effect of EA with local anaesthetic (LA) on recovery, evaluated in terms of length of hospital stay, pain intensity, duration of ileus, incidence of complications and side-effects.
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This systematic review has shown that EA does not shorten the duration of hospital stay after colorectal surgery, despite being associated with a significant decrease in VAS pain score and duration of ileus. Improved analgesia with EA compared with parenteral opioids has been demonstrated for 2 days after surgery in a recent meta-analysis, supporting the findings of the present review4.
Another systematic review has also documented a reduction of postoperative ileus after major abdominal surgery30. Postoperative ileus is one of the most significant side-effects and one of the limiting factors for early recovery after colonic surgery31. Gastrointestinal dysfunction after abdominal surgery may have numerous causes, including autonomic nervous system dysfunction, inflammatory response, anaesthetic and opioid administration, and gastrointestinal hormone disruption2. The mechanism of ileus shortening by EA may include a decrease in sympathetic tone, stress response and inflammatory processes2. The benefits of reduction of ileus include patient comfort and facilitation of oral feeding. Other strategies, however, such as administration of gastrointestinal opioid receptor antagonists or multimodal analgesia using anti-inflammatory drugs, have also been demonstrated to speed recovery of bowel function after abdominal surgery31, 32. Moreover, an epidural catheter may be associated with inadequate analgesia or technical failure. In a large RCT comparing epidural with systemic analgesia, almost 40 per cent of the patients assigned to EA had the catheter removed prematurely33. Indeed, Zutshi and colleagues29 have recently questioned the benefit of using EA after colorectal surgery when patients receive fast-track postoperative care29.
Anastomotic leakage is the most important surgical complication after colonic procedures; it may increase morbidity, duration of hospital stay and mortality. The frequency of detectable leakage varies from 6 to 15 per cent10, 17–19, 22, 23, 25. The stimulatory effect of EA on gastrointestinal mobility may lead to some theoretical concern about increasing anastomotic leakage but, on the other hand, segmental autonomic blockade may increase the blood supply to the anastomosis and improve healing. In the present meta-analysis, the anastomotic leak rate was much the same whatever the analgesic technique. Shortening the delay to recovery of bowel function has no drawback in terms of anastomotic leakage, contrary to previous suggestions34.
EA may facilitate physiotherapy and ambulation. Moreover, it attenuates the hormonal and metabolic stress response to surgery and improves homeostasis35. Taken together with the shortening of ileus, these benefits might be expected to lead to a reduction in postoperative morbidity and hospital stay. Despite better pain control, however, two large RCTs have failed to demonstrate any benefit in terms of mortality, morbidity and duration of hospital stay with EA8, 33. Still, these studies did not employ specific perioperative care to accelerate postoperative recovery, such as early mobilization and oral feeding, and avoiding routine postoperative nasogastric decompression and mechanical bowel preparation36, 37. Significant improvements in postoperative recovery and reduced hospital stay have, indeed, been demonstrated thanks to multimodal rehabilitation programmes38. In the present review, the L'Abbé plot of duration of hospital stay according to the analgesic technique shows that the most recently published trials document a shorter length of hospital stay; its mean duration had decreased from over 2 weeks to less than 1 week in the most recent reports.
One might argue that discharge criteria may have been set several hours or days before the discharge event, and that duration of hospital stay depends on factors other than medical ones. Indeed Liu and co-workers5 have reported a difference in postoperative ileus and discharge criteria in patients having colonic surgery with EA compared with those receiving intravenous PCA morphine, but they failed find any difference in hospital stay. Nevertheless, as noted above, the duration of stay has decreased in recent years while the lack of difference between EA and parenteral analgesia groups has persisted.
More important than year of publication is whether a rehabilitation programme was or was not used. A multimodal approach is considered to limit the undesirable consequences of surgery, to reduce morbidity and so improve the postoperative period39. This strategy is based on multimodal analgesia, active oral renutrition after surgery, minimally invasive surgery and adequate pain relief. Such an approach has been shown both to reduce hospital stay and to enhance recovery after colonic surgery6. Not surprisingly, the most recently published studies included in the present review used a multimodal approach in addition to EA or systemic opioid analgesia5, 10, 19–20, 27–29. Interestingly, these studies have shown that hospital stay after colorectal surgery is now less than 10 days (Fig.4). The present review suggests that it is the multimodal programme rather than the analgesic technique that improves recovery.
Combination of trials that differ in terms of underlying condition, operation and intervention in a meta-analysis is inappropriate, and so only patients having colorectal surgery were included in the present work. The aim was to increase clinical homogeneity between trials. Rehabilitation programmes in addition to EA have been used in some trials and not in others but it is noteworthy that the lack of effect of EA on length of hospital stay is homogeneous across a set of trials that were clearly heterogeneous in terms of postoperative management. Another limitation of the meta-analysis is the poor methodological quality of the studies and the small number of patients included40, 41. The method of randomization was often not described in sufficient detail and blinding assessment of outcomes was not performed, probably because of ethical concern about the placement of sham epidural catheters. Finally, the absence of double-blinding might theoretically have overvalued the effect of EA on some measures of postoperative recovery41. However, others have suggested that individual quality measures, such as blinding, are not reliably associated with the strength of treatment effect in a meta-analysis of RCTs42.
Another limitation is that duration of hospital stay was not pre-established according to specific discharge criteria. In fact, duration of stay was evaluated as a secondary endpoint in most of the studies included in the present work and may depend on many components, such as departmental organization, healthcare system and professional habits. A multimodal recovery programme after colonic surgery with pre-established endpoints reduces the hospital stay6. The gap between readiness for discharge and length of hospital stay represents real life, where discharge may be difficult despite better analgesia and shorter postoperative ileus43. EA alone is not sufficient to shorten hospital stay after elective colorectal surgery, although it should be included in fast-track programmes within a structured surgical departmental organization38, 43.
In conclusion, the present review supports the beneficial effect of EA on pain control and gastrointestinal dysfunction after colorectal surgery. These advantages, however, do not shorten hospital stay. Rather than focusing on specific analgesic techniques, future studies on postoperative care and duration of hospital stay should adopt a global approach to patient management.