Does surgical approach affect headache relief in patients undergoing cervical fusion for subaxial cervical spondylotic myelopathy? A Spine CORe™ analysis of QOD data

OBJECTIVE: Headache is a common complaint associated with cervical spondylotic myelopathy (CSM), presenting in more than one-third of patients. Surgical treatment of CSM has been linked to improved headache symptoms. The etiology of headache associated with subaxial cervical spine disorders is not well understood, nor is the mechanism of surgery in relieving symptom intensity. The authors hypothesized that surgical treatment of CSM has a positive impact on patients with headache symptoms, and that anterior cervical discectomy and fusion (ACDF) provides simpler access to foraminal decompression without disruption of posterior myofascial planes and thus could better relieve cervicogenic headache symptoms than a posterior approach. The present study seeks to compare the effect of posterior versus anterior approaches on headache symptom relief in patients with CSM. METHODS: The authors conducted a post hoc analysis of prospectively collected data from the 14-site Spine CORe™ study group using their data from the cervical module of the Quality Outcomes Database (QOD). Patients who underwent cervical surgery via ACDF or posterior cervical laminectomy and fusion (PCLF) to treat CSM were included and reviewed. The primary outcome of Neck Disability Index (NDI) headache scores (Likert scale 0-5) were collected at baseline and at 3, 12, 24, and 60 months postoperatively. Patients with a minimum preoperative headache score of 1 at baseline were included in the analysis. RESULTS: Of a total of 1085 patients in the QOD database, 697 with CSM and 5-year follow-up data endorsed headache preoperatively, with a median NDI headache score of 2 and a mean NDI headache score of 2.4 at baseline. The mean patient age was 58.6 (SD 11.5) years, 490 (70.3%) had concurrent neck pain and 251 (36.0%) had concurrent C2 (n = 3, 0.4%), C3 (n = 107, 15.4%), or C4 (n = 141, 20.2%) radiculopathy. Four hundred nineteen patients (60.1%) underwent ACDF, 119 (17.1%) underwent PCLF, with the remaining 159 (22.8%) undergoing anterior decompressions without fusion, laminoplasties, laminectomies, foraminotomies, or a combination of nonfusion decompression procedures. Postoperative headache intensities were lower than baseline intensities (Kruskal-Wallis test = 373, p < 0.0001) by a median of 1 point. By the end of the 5-year follow up, 365 (87.1%) of the ACDF patients and 99 (83.2%) of the PCLF patients experienced at least some headache relief (χ2 = 0.49, p = 0.48), defined by ≥ 1-point ordinal scale improvement of the headache score. Furthermore, 201 (48%) ACDF and 42 (35.3%) PCLF patients experienced full headache relief (χ2 = 6.01, p = 0.01), defined as a decrease to a score of zero postoperatively. There was no effect of age (β = 0.5221, p = 0.32), concurrent neck pain (U = 46476, p = 0.56), or C2-4 radiculopathy (U = 24682, p = 0.98) on headache relief by the end of follow-up. CONCLUSIONS: Surgical treatment of CSM improved symptom intensity in patients experiencing preoperative headache. ACDF and PCLF were equally effective in relieving headache at 3-60 months postoperatively. Postoperative headache relief was not affected by surgical approach, age, concurrent neck pain, or concurrent C2-4 radiculopathy.