Technique to minimize paraspinal muscle atrophy after posterior cervical fusion

Paraspinal muscle atrophy (PMA) after posterior cervical fusion is a known complication that causes considerable morbidity. It has been shown in the lumbar spine that preservation of the posterior ramus of the spinal nerve is important in minimizing paraspinal muscle atrophy. During posterior cervical spine fusions, we modified the exposure of the dorsal cervical spine by exposing only the medial two-thirds of the lateral mass utilizing a low electrocautery setting. In a retrospective analysis, we compared the incidence of paraspinal muscle atrophy using this modified technique with historical cohorts who underwent posterior cervical fusion using the standard technique of exposure of the entire lateral mass.

All patients who underwent posterior cervical fusion and internal fixation between 1999 and 2007 were included. Patients operated from 1999 to 2003 who underwent the standard exposure of the lateral mass formed Group 1 (n=31). Group 2 (n=32) included patients whose lateral masses were exposed using the modified technique of limiting the exposure only to the medial two-thirds of the lateral mass with the cautery on a low setting. All patients were assessed for PMA at six months after surgery. Atrophy was graded as no atrophy, mild atrophy (minimal midline atrophy), moderate atrophy (muscle lost without palpable hardware) and severe atrophy (hardware palpable). Before initiating the study, no atrophy and mild atrophy were grouped together as a non-significant atrophy and moderate atrophy and severe atrophy were grouped together as significant atrophy.

We found a statistically lower incidence of paraspinal atrophy using this modified exposure of the lateral mass (p<0.03).

This modified technique of cervical spine exposure is associated with lower paraspinal muscle atrophy secondary to the preservation of the innervation of the paraspinal musculature.