The effects of neuromuscular blockade on operating conditions during general anesthesia for spinal surgery

Muscle relaxants are prescribed routinely for patients undergoing general anesthesia, but the requirement for paralysis in spinal surgery is unclear. This study compared the operating conditions of general anesthesia with and without a muscle relaxant on spinal surgery patients.

Eighty-six adults who underwent elective spinal surgery were randomly assigned to a relaxant group (group R) or a no-relaxant group (group NR). All patients were induced with intravenous midazolam (0.05 mg/kg), fentanyl (4 µg/kg), propofol (1.0 mg/kg), and succinylcholine (2 mg/kg) and then atracurium was used in group R but not in group NR. The operating conditions, including muscle tone, body movements, airway pressure, anesthetics consumption, eye-opening time, extubation time, and the Observer's Assessment of the Alertness/Sedation (OAA/S) score 20 minutes after the extubation were compared between the 2 groups.

The operating conditions including muscle tone scales, body movements, and airway pressure did not differ between the 2 groups. Eye-opening time (9.35±2.34 vs. 11.02±2.50 min; P=0.002) and extubation time (13.95±3.41 vs. 16.72±3.67 min; P=0.001) were shorter in group NR than in group R. The BIS score at extubation (87.2±5.0 vs. 83.3±5.7; P=0.001) and the OAA/S score 20 minutes after extubation (5 [3 to 5] vs. 4 [3 to 5]; P=0.005) were significantly higher in group NR than in group R. Propofol consumption was higher in group NR than in group R (4206.10±415.80 vs. 3900.60±365.40 μg/kg, respectively; P=0.001).

General anesthesia without muscle relaxant provides similar working conditions to those observed with muscle relaxant, and it is associated with earlier eye opening and extubation and higher level of consciousness on emergence from spinal surgery.