Effects of intraoperative-intrathecal sufentanil injection on postoperative pain management after single level lumbar discectomy.

BACKGROUND For lumbar disc operation a chain of painful procedures including skin incision, muscle dissection and sometimes laminectomy should be performed. The combination of these manoeuvres results in significant post-operative pain. The standard way to reduce post-operative pain consist of intra-operative injection of local anaesthetic (Bupivicaine or Lidocaine) to the superficial tissues and intravenous, oral or rectal prescription of Opioid analgesics or other analgesics after operation, but inadequate analgesia, constipation and delayed mobilisation are frequent side effect of those treatments. The goal of this study was to reduce postoperative pain of patients which causes a reduction in analgesic consumption and eventually shortened hospital stay and acceleration in physical therapy programs and ambulation. MATERIALS AND METHODS After ethical comitte approval, patients allocated in two groups A and B. Each group consisted 30 patients which all of them underwent general anesthesia. All of operations performed by same surgeon... After discectomy and at the end of surgery based on patients odd or even number of hospital admission, one group (group-A) received sufentanil (Iranian pharmaceutic company) 0.05/kg intrathecaly injected in surgical level and the placebo group (group-B) normal saline was injected. In recovery room when patients were sufficiently awake for pain assessment, patients were asked to score pain on the verbal pain assessment score In both groups we compaired pain scores pre and postoperativly. The total dose of opioid requirement for patients and its time after operation was recorded. RESULTS Of the 60 patients (ASA classes I and II) entering the study, no one excluded during our study. 30 patients received intrathecal injection of sufentanil as group-A or case and 30 patients normal saline as group-B or control. Mean age between two groups showed no significant difference. 45.7 year (SD = 11.5) for group-A and 44.3 year (SD = 9.9) for group-B which did not differ between two groups (P = 0.617). Urinary retension happened in 3 patients of group-A and 3 patients of group-B (P = 1). Pruritis happened in 1 patient of group-A and no patient in group-B (P = 0.15). Patients in group-A had reduced analgesic requirments (P = 0.01). Preoperative low back pain based on NPS (numerical pain scores) criteria in group-A shows score 1, (n = 7) score 2, (n = 10) score 3, (n = 11) and score 4 (n = 2) (mean = 2.2667 and SD = 0.9072). These scores in group-B showed score 2 (n = 4) score 3 (n = 16) and score 4 (n = 10) (mean = 3.2 and SD = 0.6644) (P < 0.001). After surgery low back pain assessment in two groups shows in group-A three patients had score 1, score 2, (n = 7) score 3, (n = 11) score 4, (n = 8) score 5 (n = 1) (mean = 2.9 and SD = 1.0289) and in group-B score 4 (n = 17) score 5 (n = 13) (mean = 4.4333 and SD = 0.5040) (P < 0.001). Preoperative lower extremity radicular pain assessment in two groups shows a mean pain score of 8.3 with SD = 0.9523 in group-A and a mean of 8.3448 with SD = 1.1109 in group-B and after operation a mean pain score of 1.7333 with SD = 0.8277 in group-A and a mean of 4.1667 with SD = 0.7466 in group-B. In walking ability assessments pre and postoperatively based on Mann-Whitney test it is shown that in group-A walking ability is better than group-B (P < 0.001). CONCLUSION In this study we studied the efficacy of intraoperative-intrathecal sufentanil injection versus placebo on post operative pain management. Our study showed that intrathecal (IT) sufentanil provided more effective analgesia postoperatively after single level discectomy. Urinary retention was equal in two groups. For more exact conclusions it is better to do a similar study on more patients.