Object: No previous hypothesis has attempted to fully account for the occurrence of upper-limb palsy (ULP) after cervical laminoplasty. The authors propose that friction-generated heat from a high-speed drill may cause thermal injury to the nerve roots close to the drilled bone, which may then lead to ULP. The authors investigated the effect of cooling the saline used for irrigation during the drilling on the incidence of upper-limb (C-5) palsy following cervical laminoplasty.
Methods: The irrigation saline for drilling was used at room temperature (RT, average temperature of 25.6°C) in operations of 79 patients (the RT group) and cooled to an average of 12.1°C in operations of 80 patients (the low-temperature [LT] group). The authors used a hand-held dynamometer to precisely assess muscle strength presurgery and 2 weeks postsurgery.
Results: There was a 7.6% and 1.9% decrease in the strength of the deltoid muscle, a 10.1% and 4.4% decrease in the strength of the biceps brachii, a 1.3% and 0.6% decrease in the strength of the triceps brachii, and a 7.6% and 3.1% decrease in grip strength in the RT and LT groups, respectively. Multivariate analysis revealed that a significant predictor for decreased deltoid muscle strength was the use of irrigation saline at RT.
Conclusions: Using cooled irrigation saline during bone drilling significantly decreased the incidence of ULP and can thus be recommended as a simple method for the prevention of ULP.