A Helpful Third Portal for Unilateral Biportal Endoscopic Decompression in Patients with Cervical Spondylotic Myelopathy: A Technical Note

Unilateral biportal endoscopic (UBE) laminotomy with bilateral decompression is a high-risk operation when performed in the cervical spine. In this study, we aimed to design an auxiliary portal for treatment of cervical spondylotic myelopathy using a percutaneous biportal endoscopic approach.Six patients with cervical spondylotic myelopathy were consecutively treated using an auxiliary portal (Zhang's portal) during percutaneous biportal endoscopic surgery between June 2020 and July 2021. Clinical outcomes were assessed by comparing preoperative and postoperative Japanese Orthopaedic Association scores and status based on modified Macnab criteria.The study enrolled 6 patients (2 men and 4 women; mean age, 51.6 ± 10.8 years). The mean operative time was 78.6 ± 37.4 minutes. There were no cases of infection, cerebrospinal fluid leakage, or neurological complications. The mean Japanese Orthopaedic Association score improved from 7.5 to 12.1. At final follow-up, outcomes were considered excellent for all patients based on modified Macnab criteria.Zhang's portal can allow for safe, flexible, and convenient contralateral decompression without the need to remove excessive portions of bone from the spinous process. Our results suggest that applying Zhang's portal in unilateral biportal endoscopy surgery represents an alternative when aiming to decompress the contralateral canal in patients with cervical spondylotic myelopathy caused by hypertrophy of the ligamentum flavum.