Background: In lateral cervical disc herniations, posterior foraminotomy (PF) provides direct nerve root decompression and maintains segmental mobility. However, partial facetectomy can cause instability. This study evaluated long-term clinical outcomes related to cervical sagittal alignment after PF.
Methods: The study included 48 consecutive patients with lateral cervical disc herniations who underwent PF. Pain and mobility were evaluated using the Numeric Rating Scale and Neck Disability Index (NDI), respectively. Sagittal alignment was evaluated using the modified Toyama method.
Results: Median Numeric Rating Scale arm, Numeric Rating Scale neck, and NDI scores improved by 7, 4.5, and 24 points, respectively. Corresponding mean minimal clinically important differences were achieved in 94%, 77%, and 98% of patients at a mean follow-up of 8.4 years. Of patients, 82% showed favorable radiological results (i.e., retained or developed lordosis or had straight spine), while 18% showed unfavorable radiological results (i.e., retained or changed toward kyphosis). The latter group had multilevel cervical degenerative disc disease (mcDDD) before 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 minimal clinically important differences, 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 benefited from PF. Sagittal alignment improved in >40% of patients, but coexisting mcDDD was a main risk factor for kyphosis persistence.
Keywords: Cervical degenerative disc disease; Cervical discopathy; Modified Toyama method; Posterior foraminotomy.
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