A randomized controlled trial evaluating the impact of selective axillary nerve block after arthroscopic subacromial decompression.

BACKGROUND: The sensory innervation of the shoulder is complex and there are variations in the branching patterns of the sensory fibres. Articular branches from the axillary nerve to the subacromial bursa are described in more than 50% of investigated shoulders but the isolated contribution of sensory input from the axillary nerve has never been investigated clinically. We hypothesized that a selective block of the axillary nerve would reduce morphine consumption and pain after arthroscopic subacromial decompression. METHODS: We included 60 patients in a randomized, blinded, placebo-controlled study. Patients were randomized to a preoperative selective ultrasound-guided axillary nerve block with 20 mL ropivacaine (7.5 mg/mL) or 20 mL saline. Primary outcome was intravenous morphine consumption 0-4 h postoperatively. Secondary outcome was postoperative pain evaluated by a visual analogue scale (VAS) score (0-100). RESULTS: We analysed data from 50 patients and found no significant difference in 0-4 h postoperative morphine consumption between the two groups (ropivacaine 14 mg, placebo 18 mg (P = 0.12)). There was a reduction in postoperative pain: VAS 0-4 h (area under the curve) (ropivacaine 135, placebo 182 (P = 0.03)), VAS after 8 h (ropivacaine 9, placebo 20 (P = 0.01)) and VAS after 24 h (ropivacaine 7, placebo 18 (P = 0.04)). Eight out of 19 patients with a successful selective axillary nerve block needed an interscalene brachial plexus escape block. CONCLUSIONS: Selective block of the axillary nerve has some pain relieving effect, but in this setting the effect was unpredictable, variable and far from sufficient in a large proportion of the patients. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01463865). Registered: November 1, 2011.

Pharmacokinetics of Repeated Melatonin Drug Administrations Prior to and After Surgery.

BACKGROUND: Recent clinical studies have documented the analgesic, anti-inflammatory, antioxidative and anxiolytic effects of exogenous melatonin. The pharmacokinetic properties of melatonin have primarily been investigated in experimental studies. OBJECTIVE: The aim of this study was to estimate the pharmacokinetics of melatonin in patients undergoing surgery and general anesthesia. METHODS: The study was designed as a prospective, two-phase cohort study. Patients were candidates for subpectoral breast augmentation surgery, and surgical procedures were performed by a single surgeon. The perioperative treatment protocol was standardized between patients. During the study, each patient received two separate oral administrations of melatonin 10 mg. Melatonin was administered 60 min before surgery, and at 9:00 p.m. the evening after surgery. The pharmacokinetic variables absorption half-life (t ½ absorption), time to maximal plasma concentration (T max), maximal plasma concentration (C max), elimination half-life (t ½ elimination), and area under the melatonin plasma concentration-time curve from time zero to infinity (AUC ∞) were estimated for both study phases. RESULTS: Median (interquartile range) values of t ½ absorption and T max were significantly increased during the postoperative phase [10.8 (6.9-15.1) min; 90.0 (48.8-120.0) min] compared with perioperatively [9.5 (6.3-16.5) min; 30.0 (15.0-30.0) min] (p = 0.034; p = 0.002), respectively. C max values were significantly higher during surgery [5497.5 (2077.1-13,233.8) pg/ml] compared with postoperative values [2340.5 (1672.4-8871.4) pg/ml] (p = 0.005). Correspondingly, t ½ elimination was significantly extended during the postoperative phase [103.5 (57.8-237.8) min] compared with the perioperative phase [60.5 (47.8-83.6) min] (p = 0.015). AUC ∞ did not differ between the study phases (p > 0.05). CONCLUSIONS: These preliminary results indicate that postoperative melatonin dose should be augmented compared with preoperative administration if corresponding melatonin plasma levels are intended. Furthermore, postoperative administration times should be advanced compared with preoperative administration.