Clinical application of square hook knife assisted posterior longitudinal ligament resection in anterior decompression surgery of cervical spondylosis

Objective To explore the clinical effect and safety of square hook knife in the resection of the longitudinal ligament after anterior decompression surgery of cervical spondylosis. Methods The clinical data of 43 cases of cervical spondylosis with square hook knife assisted cervical longitudinal ligament resection in the Department of Orthopedics of Luoyang Orthopedic Hospital of Henan Province from September 2015 to June 2017 were analyzed retrospectively. There were 23 males and 20 females with an age of 38-69 (54.2±8.3) years. According to the classification of cervical spondylosis, there were 13 patients of nerve root type, 21 patients of spinal cord type and 9 patients of mixed type. The safety, postoperative efficacy and complications of this method were also analyzed. The operative time, intraoperative blood loss, postoperative hospital stay and postoperative complications were observed. According to the Japanese Orthopaedic Association(JOA) score at the last follow-up, the improvement rate of cervical spinal cord function was calculated to evaluate the clinical efficacy. Results All patients have a smooth operation and 2 patients with cerebrospinal fluid leakage were recovered after conservative treatment. The operative time was 67-170 (102.4±20.7) minutes, the intraoperative blood loss was 50-280(160.6±51.2) mL, and the postoperative hospital stay was 5-11 (7.8±1.3) days. Of the 43 patients, 38 were followed up for 8-17 (10.5±2.1) months. No postoperative hoarseness, hematoma, infection, failure of internal fixation and other complications occurred. The preoperative JOA scores were 6-11(8.7±1.3)points, and the JOA scores were 10-17 (15.6±1.1) points at the end of follow-up. The improvement rates of cervical spinal cord function were 65.8%-93.6%(83.1%±6.8%). The curative effects were excellent in 8 patients, good in 24 patients, common in 5 patients and poor in 1 case, with an excellent rate of 84.2%. Conclusions It is safe and reliable to remove the posterior longitudinal ligament with square hook knife in anterior cervical approach, which is beneficial to the recovery of spinal cord shape and nerve function, and the clinical effect is satisfactory. Key words: Cervical spondylosis; Decompression of anterior cervical approach; Square hook knife; Posterior longitudinal ligament