Does Segmental Kyphosis Affect Surgical Outcome after a Posterior Decompressive Laminectomy in Multisegmental Cervical Spondylotic Myelopathy?

STUDY DESIGN Retrospective analysis. PURPOSE To compare results of laminectomy in multisegmental compressive cervical myelopathy (CSM) with lordosis versus segmental kyphosis. OVERVIEW OF LITERATURE Laminectomy is an established procedure for decompression in CSM with cervical lordosis. However in patients with segmental kyphosis, it is associated with risk of progression of kyphosis and poor outcome. Whether this loss of sagittal alignment affects functional outcome is not clear. METHODS We retrospectively reviewed 68 patients who underwent laminectomy for CSM from 1998 to 2009. As per preoperative magnetic resonance images, 36 patients had preoperative lordosis (Group 1) and 32 had segmental kyphosis (Group 2). We studied age at the time of surgery, duration of preoperative symptoms, recovery rate, magnitude of postoperative backward shifting of spinal cord and loss of sagittal alignment. RESULTS Mean follow up was 5.05 years (range, 2-13 years) and mean age at the time of surgery 61.88 years. Group 1 had 20 men and 16 women and Group 2 had 19 men and 13 women. Mean recovery rate in Group 1 was 60.32%, in Group 2 was 63.7% without any statistical difference (p-value 0.21, one tailed analysis of variance). Two patients of Group 1 had loss of cervical lordosis by five degrees. In Group 2 seven patients had progression of segmental kyphosis by 5-10 degrees and two patients by more than 10 degrees. Mean cord shift was more in Group 1 (mean, 2.41 mm) as compared to Group 2 (mean, -1.97 mm) but it had no correlation to recovery rate. Patients with younger age (mean, 57 years) and less duration of preoperative symptoms (mean, 4.86 years) had better recovery rate (75%). CONCLUSIONS Clinical outcome in CSM is not related to preoperative cervical spine alignment. Thus, lordosis is not mandatory for planning laminectomy in CSM. Good outcome is expected in younger patients operated earliest after onset of symptoms.