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Regression of Anterior Disc-osteophyte Complex Following Cervical Laminectomy and Fusion for Cervical Spondylotic Myelopathy.

STUDY DESIGN
Retrospective case control study.


OBJECTIVE
To investigate whether posterior cervical laminectomy and fusion modifies the natural course of anterior disc-osteophyte complex in patients with multilevel CSM.


SUMMARY OF BACKGROUND DATA
Dorsal migration of the spinal cord is the main purported mechanism of spinal cord decompression following cervical laminectomy and fusion but other potential mechanisms have received scant attention in the literature. This study was conducted to investigate whether cervical laminectomy and fusion affects the size of anterior disc osteophyte complex.


METHODS
The medical records and radiographical imaging of 44 patients that underwent cervical laminectomy and fusion for CSM between 2006 and 2013 were analyzed. The size of the anterior disc osteophyte complex was measured pre and postoperatively on MR images taken at an interval of >3 months apart. A control group consisted of 20 non-operatively treated advanced cervical spondylosis patients. Patients in the control met the same inclusion and exclusion criteria and also had sequential MRI taken at an interval of >3 months apart.


RESULTS
The nonoperative and operative groups were statistically similar in the pertinent patient demographics and characteristics including gender, age, time to second MRI, size of anterior disc-osteophyte complex on baseline MRI, mean number of levels affected, and percentage of patients with T2 signal change. As expected the mJOA scores were significantly lower in the operative versus nonoperative cohort (13.6 vs. 16.5, P<0.01). A significant decrease in the size of anterior disc osteophyte was observed in the operative group postoperatively (P<0.01). In comparison, there was no statistically significant change in the size of the anterior disc osteophyte complex in the control group (P>0.05). The magnitude of the change in disc size between the two groups was statistically significant (P<0.01).


CONCLUSION
The findings of this study suggest that regression of anterior-disc osteophyte complex occurs following cervical laminectomy and fusion, and likely provides another mechanism of spinal cord decompression.