This study focused on revision surgical methods and outcomes of two-level ASD in 32 patients who recently developed neurological symptoms similar with 2 lesions in the adjacent segments proved by MRI, comprising 10 patients who had index surgeries. Both anterior and posterior decompression and fusion proved effective for patients with two-level symptomatic ASD.

This study aimed to distinguish between the clinical and radiological outcomes of repeat anterior and posterior decompression and fusion techniques for two-level symptomatic adjacent segment disease (ASD).

A total of 32 patients with two-level symptomatic ASD were retrospectively reviewed. Out of which, 18 underwent repeat anterior cervical discectomy and fusion (ACDF). And, 14 patients who underwent posterior decompression and fusion (PDF) were older; more commonly reported with myelopathic deficits, and were fused at additional levels. 

A comparison of clinical outcomes (i.e. Japanese Orthopedic Association, JOA; Neck Disability Index, NDI; and VAS scores), perioperative parameters (blood loss, operation time, and hospital stay duration), radiological factors (cervical lordosis and ROM), and complications were compared.

Patients who underwent ACDF had significantly shorter surgery time, lesser blood loss, and decreased hospital stay. Significant increases in JOA scores and decreases in NDI and both neck pain and arm pain VAS scores were observed in both the groups (figure 1), however, patients who undertook PDF had considerably higher NDI scores, neck pain VAS scores, loss of cervical lordosis and ROM. In the ACDF group, 3 patients developed dysphagia, and 2 patients had C5 root palsy and 1 had hematoma in the PDF group. 

Repeated ASD following the second operation arose in 2 patients in the ACDF group however no patients in the PDF group.

Both anterior and posterior decompression and fusion effectively improved neurological function for patients with two-level symptomatic ASD. ACDF had less surgical trauma, improved restoration of lordosis, and less neck pain after the operation, nevertheless higher possibility of recurrent ASD for patients with radicular symptoms. In elderly patients with myelopathy developing in adjacent segments, PDF proved to be an effective surgical alternative.