A Prospective Randomised study comparing postoperative outcome after Regional or General Anesthesia for Incisional Hernia Surgery in Obese Patients

INTRODUCTION: Incisional hernia is the most frequent postoperative complication following abdominal surgery. The cumulative incidence has remained constant despite several attempts to improve laparotomy closure. Surgical closure technique, individual, biological and patient dependent risk factors play a key role. Recent advances in anesthesia techniques, adequate prevention and treatment of infection during surgery, and the use of new suture materials though have reduced the incidence of incisional hernia. Nevertheless, incisional hernia still occurs in 0.5% to 11% of all laparotomies performed. It has been estimated that about half of incisional hernias will develop within 3 months of the initial abdominal procedure. Surgical repair may be established by open or laparoscopic approaches. Some of the well-known factors affecting recurrence rates are obesity, large incision size, preoperative presence of mesh and postoperative wound infection. Incisional hernia surgery is considered as a major abdominal procedure and can be performed under general anesthesia, regional anesthesia or both combined together. Any surgery is associated with stress responses and this contribute to various organ dysfunctions. Pain relief may be a powerful technique to modify surgical stress response. It has been assumed that sufficient pain relief will improve the surgical outcome and there is a common consensus that optimal pain relief is a prerequisite for early postoperative recovery.12The effect of epidural anesthesia and analgesia on high risk patients coming for major abdominal surgery has been studied in mid 1980s by Yeager and colleagues on 53 patients, which has shown significant improvement in postoperative outcome. Multimodal analgesia programs have shown to decrease hospital stay and improve postoperative recovery. The most commonly used pain-relieving techniques for major abdominal surgeries are patient controlled analgesia with opioids, non-steroidal anti-inflammatory drugs and epidural analgesic techniques. Evidence suggests that epidural local anesthetic or local anesthetic-opioid techniques are the most effective in providing dynamic pain relief, after major surgical procedures. The duration of epidural local anesthetic analgesia is important, atleast 24 hours and preferably 48 hours. The MASTER (Multicentre Australian Study of Epidural Anesthesia) RCT investigated the influence of perioperative epidural analgesia on outcome in 888 patients undergoing major abdominal surgery in between 1995 and 2001 from 25 hospitals in six countries. These patients were considered high risk because of the presence of one or more important co-morbidities. In comparison with a control group who received intravenous (IV) opioid analgesia, they found no difference in mortality or in the incidence of major morbidity with the exception of the incidence of respiratory failure. However, postoperative analgesia was found to be clinically superior on the basis of pain visual analog scores (VAS) in patients randomized to the epidural group. In the epidural group, mean pain VAS with coughing was 30% less than in the control group in the first 24 hours after surgery and 20% less for the remaining 48 hours. A systemic overview was conducted by Rodgers and colleagues in year 2000 of 141 available randomized controlled trials, including 9559 patients till January 1997. It showed that the use of epidural and spinal block resulted in a statistically and clinically significant reduction in morbidity and mortality after surgery. AIM OF THE STUDY: To test the efficacy and evaluate the impact of epidural anesthesia and postoperative epidural analgesia on postoperative outcomes in obese patients undergoing incisional hernia surgery. MATERIAL AND METHODS: The aim of the study was to test the efficacy and evaluate the impact of epidural anesthesia and analgesia on postoperative outcomes in obese patients undergoing incisional hernia surgery. After obtaining institutional review board approval and written informed consent, an open randomized controlled trial was conducted on 60 patients scheduled for elective incisional hernia surgery. Sample size: The sample size was calculated as 30 in each group based on Franco Carli et al study. A sample size of 30 was calculated in each group with 80% power to detect a difference of 2.2 in the means of Visual Analogue Scale the primary outcome, assuming the common standard deviation of 2.7, and the test to be performed at 5% significance level (two-sided). In this open trial, patients undergoing elective incisional hernia surgery was randomized either to receive general anesthesia with subcutaneous morphine for postoperative analgesia (control group) or spinal anesthesia with postoperative epidural analgesia with bupivacaine and fentanyl (regional group). Inclusion criteria: 1. Patients aged between 18 and 60 years. 2. American Society Anesthesia class I, II. (ASA Risk categorization). 3. Scheduled for incisional hernia as elective planned surgery. 4. Calculated Body Mass Index(BMI) more than 25. Exclusion criteria: 1. Pediatric and geriatric age group. 2. Pregnancy. 3. Known allergy to any anesthetic agent. 4. Scheduled for emergency surgery. 5. Contraindications to regional anesthetic technique. 6. Failure in performing the anesthetic technique. Consent: Consent for either anesthetic technique was taken in the pre anesthetic clinic (PAC). The risk and benefits of either anesthetic techniques were explained. Statistical analysis: All the study variables are described using either mean with standard deviations or absolute numbers with frequency percentages as appropriate. Baseline comparisons between the two study groups are made. Comparisons for quantitative variables are made using Student’s t-test and chi-square test was used for categorical variables. A p value of less than 0.05 was considered statistically significant. The data were coded and entered into Microsoft Excel computer programme and analysed using software STATA,VERSION 8. CONCLUSION: Combined spinal epidural is a superior alternative technique to general anesthesia with parenteral opioids in the post operative management of incisional hernia surgery for obese patients. Combined spinal epidural technique provides better pain relief, early bowel recovery, less incidence of hypoxia and nausea and better patient satisfaction in postoperative period in obese patients.