Long-term Clinical Results with Radiological Correlations after Posterior Foraminotomy for Unilateral Cervical Discopathy.

Abstract BACKGROUND In lateral cervical disc herniations, a posterior foraminotomy (PF) provides direct nerve root decompression and maintains segmental mobility. However, a partial facetectomy can cause instability. This study evaluated long-term clinical outcomes related to cervical sagittal alignment after PF. MATERIALS: We included 48 consecutive patients with lateral cervical disc herniations that underwent PF. Pain and mobility were evaluated using the numerical rating scale (NRS) and the Neck Disability Index (NDI), respectively. Sagittal alignment was evaluated using the modified Toyama method. RESULTS The median arm NRS, neck NRS, and NDI scores improved by 7, 4.5, and 24 points, respectively. Corresponding mean minimal clinically important differences (MCIDs) were achieved in 94%, 77%, and 98% of patients, respectively, at a mean follow-up of 8.4 years, and 82% of patients showed favorable radiological results (i.e., retained or developed lordosis or had straight spine), while 18% of patients showed unfavorable radiological results (i.e., retained or changed toward kyphosis). The latter group had multilevel cervical degenerative disc disease (mcDDD) before the PF. Nevertheless, the risk of developing kyphosis was only 2.6% and the potential for improving sagittal balance was 43%. Follow-up median NDI scores, but not MCIDs, were significantly worse in patients with preoperative kyphosis (21 vs. 8; P= 0.03) or mcDDD (20 vs. 8; P= 0.024) compared with other patients. CONCLUSIONS Patients with preoperative kyphosis or mcDDD had worse NDI outcomes but also benefitted from PF. Sagittal alignment improved in over 40% of patients, but coexisting mcDDD was a main risk factor for kyphosis persistence.