Photogrammetric analysis: An objective measure to assess the craniocervical range of motion after cervical laminoplasty surgeries

Abstract

Surgical decompression using laminoplasty is commonly performed for multilevel stenosis with cervical spondylotic myelopathy. However, the long-term effects on the craniocervical range of motion (ROM) after surgery are not well understood. This study represents the first entry into the literature of photogrammetric analysis for clinical measurement of craniocervical ROM. All patients underwent a French-door laminoplasty from 1995 to 2016 and were evaluated radiologically and with postoperative photographs (photogrammetric analysis) to measure craniocervical ROM and axial rotation. Radiographic parameters were occiput to C2 angle, C1–2 angle, C2–7 angle/cervical lordosis (CL), T1-slope (T1S), and TS-CL were measured. Chin-brow vertical angle (CBVA) was utilized for flexion and extension, while nose-turn angle (NTA) was used to assess axial rotation. Forty-four patients (mean age: 65.7 years, 50% female) had a mean follow-up of 37.9 months. Mean values in neutral, flexion, and extension were occiput to C2 = 30°, 15°, and 43°; C1–C2 = −32°, −25°, −32°; and C2–C7 = −4°, 11°, −20°, respectively. Mean CL was within 1 SD of the established −17° (±13.86°). Mean T1S and TS-CL were 33° and 30° in the neutral position, respectively. Mean radiographic full range of motion from flexion to extension was 53°. NTA towards patients’ left was 48° and the right side was 45°. Mean CBVA, was −4°, mean flexion 37°, and extension −45°; full range was 81°. Global craniocervical ROM has proven to be well preserved for many years following cervical laminoplasty. Photogrammetric analysis is a cost-effective and radiation-free method, accurate for quantitative assessment of craniocervical and cervical ROM.