Paravertebral somatic nerve block for outpatient inguinal herniorraphy
Introduction. Inguinal herniorrhaphy is a common outpatient surgical procedure. However, anesthetic techniques for inguinal herniorrhaphy are still associated with numerous side effects. Nausea, vomiting, puritis, urinary retention and difficult pain management can complicate care and lead to admission( 1 ). Paravertebral somatic nerve blockade (PSNB) has the potential advantage to offer unilateral abdominal wall anesthesia and long lasting post-operative pain relief with minimal side effects. To date no study has examined this technique for outpatient inguinal herniorrhaphy. This study examined the feasibility, pain relief, side effects and patient satisfaction of PSNB when used for outpatient inguinal herniorrhaphy. Methods. After Institutional Review Board approval, written informed consent was obtained from 22 patients agreeing to have their inguinal herniorrhaphy surgery under paravertebral blockade with intravenous sedation. Twenty-two patients received a PSNB at thoracic nerve 10 to lumbar nerve 2 using the techniques of Moore(2) and Katz (3). The superior aspects of the spinous processes of thoracic level 10 to lumbar level 2 were identified and the needle entry site was marked 2.5-3 cm lateral to each spinous process ipsilateral to the hernia. Using a 22-gauge 3.5 inch Quinke spinal needle attached via extension tubing to a syringe, the needle was advanced anteriorly in the parasagital plane until it contacted the transverse process. The needle was then withdrawn to the subcutaneous tissue, and angled to walk off the caudad edge of the transverse process 1-2 cm anteriorly. Then 5 ml of bupivacaine 0.5% with epinephrine 1:400,000 was injected at each of the five levels. All patients received intra-operative sedation with propofol 10-50 mcg/kg/min IV. Intermittent intravenous doses of fentanyl 25 meg and propofol 10 mg were given for supplemental sedation. Intravenous ketorolac 30 mg was administered at the conclusion of surgery. All patients were given prescriptions for oral narcotic tablets to treat post-operative pain after discharge. The onset of surgical anesthesia, duration of analgesia, side effects, and patient satisfaction with the technique were documented in the post anesthetic care unit and by repeat telephone interviews. Results, The mean age of the patients in the trial was 54 ±19 years (range 23-79). Surgical anesthesia occurred 15-30 min after injection. Two patients had a failed block, these were not included in subsequent analyses. The mean ±S.D. time to onset of discomfort was 14 ±11 hours. Time until first narcotic requirement was 22 ±18 hours. The mean number of narcotic tablets taken during the 48 hour follow-up period was 3 ±3. No narcotic tablets were required in fourteen of twenty patients in the first 12 hours. Thirteen patients (n=20) had no incisional discomfort 10 hours or longer after their blocks. Three patients had epidural spread. No patient had urinary retention. The majority of the patients (17 of 20) were very satisfied with their anesthetic technique. Conclusions. The results of our initial experience suggest that PSNB is a potentially safe and effective technique. In general, the block provided long lasting pain relief in the majority of patients with few side effects. A larger randomized study comparing paravertebral blocks with conventional anesthesia choices is suggested given the findings in this series of patients-.
Klein, SM; Greengrass, RA; Warner, DS
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