The cervical spine demonstrates less postoperative bone loss than the lumbar spine

Preoperative Decreased Hounsfield Unit Values of Cervical Vertebrae and the Relative Cross-Sectional Area of Flexion/Extension Paraspinal Muscles Are Novel Risk Factors for the Loss of Cervical Lordosis after Open-Door Laminoplasty

Open-door laminoplasty is widely used for patients with cervical spondylotic myelopathy (CSM). However, the loss of cervical lordosis (LCL) seems to be unavoidable in the long-term follow-up after surgery, which may affect the clinical outcomes. The risk factors for this complication are still unclear. In this study, patients who underwent open-door laminoplasty between April 2016 and June 2021 were enrolled. Cervical X-rays were obtained to measure the C2–7 Cobb angle, C2–7 sagittal vertical axis (SVA), T1 slope (T1S) and ranges of motion (ROM). Cervical computed tomography (CT) scans and magnetic resonance imaging (MRI) were collected to evaluate the cervical Hounsfield unit values (HU) and the relative cross-sectional area (RCSA) of paraspinal muscles, respectively. A total of 42 patients were included and the average follow-up period was 24.9 months. Among the patients, 24 cases (57.1%) had a LCL of more than 5° at a 1-year follow-up and were labeled as members of the LCL group. The follow-up JOA scores were significantly lower in the LCL group (13.9 ± 0.6 vs. 14.4 ± 0.8, p = 0.021) and the mean JOA recovery rate was negatively correlated with LCL (r = −0.409, p = 0.007). In addition, LCL was positively correlated to the preoperative T1S, flexion ROM, flexion/extension ROM and the RCSA of flexion/extension muscles, while it was negatively correlated to extension ROM and the HU value of cervical vertebrae. Furthermore, multiple linear regression showed that preoperative T1S, mean HU value of cervical vertebrae, flexion/extension ROM and the flexion/extension RCSA were independent risk factors for LCL. Spine surgeons should consider these parameters before performing open-door laminoplasty.

Reoperations after fusion surgeries for degenerative spinal diseases depending on cervical and lumbar regions: a national database study

BACKGROUND

Reoperation is one of the key factors affecting postoperative clinical outcomes. The reoperation rates of cervical surgeries might be different from those of lumbar surgeries due to the anatomical and biomechanical differences. However, there has been no study to compare the reoperation rate between them. The purpose is to compare reoperation rates after fusion surgeries for degenerative spinal diseases depending on the anatomic region of cervical and lumbar spines.

METHOD

We used the Korean Health Insurance Review & Assessment Service national database. Subjects were included if they had any of the primary procedures of fusion combined with the procedure of decompression procedures under the diagnosis of degenerative diseases (n = 42,060). We assigned the patients into two groups based on anatomical regions: cervical and lumbar fusion group (n = 11,784 vs 30,276). The primary endpoint of reoperation was the repeat of any aforementioned fusion procedures. Age, gender, presence of diabetes, associated comorbidities, and hospital types were considered potential confounding factors.

RESULTS

The reoperation rate was higher in the patients who underwent lumbar fusion surgery than in the patients who underwent cervical fusion surgery during the entire follow up period (p = 0.0275). A similar pattern was found during the late period (p = 0.0468). However, in the early period, there was no difference in reoperation rates between the two groups. Associated comorbidities and hospital type were noted to be risk factors for reoperation.

CONCLUSIONS

The incidence of reoperation was higher in the patients who underwent lumbar fusion surgery than those who underwent cervical fusion surgery for degenerative spinal diseases.