Comparison of the Anterior and Posterior Approach in Treating Four-Level Cervical Spondylotic Myelopathy

Comparison of the Anterior and Posterior Approach in Treating Four-Level Cervical Spondylotic Myelopathy

Cervical spondylotic myelopathy (CSM) is a common degenerative condition affecting individuals over the age of 55. It is characterized by compression of the spinal cord due to degenerative changes in the cervical spine. Surgical intervention is often required to decompress the spinal cord and restore stability. The two primary surgical approaches for treating CSM are the anterior and posterior approaches. However, the optimal approach for treating four-level CSM remains a topic of debate. This study aims to compare the clinical and radiological outcomes, as well as complications, between the anterior and posterior approaches for four-level CSM.

The anterior approach includes techniques such as multilevel anterior cervical discectomy and fusion (ACDF), anterior cervical corpectomy and fusion (ACCF), and hybrid decompression and fusion (HDF). These procedures directly decompress the spinal cord and improve cervical alignment. However, they are associated with certain limitations, such as a restricted surgical field and a higher risk of complications like non-union of bone grafts and implant dislodgement. On the other hand, the posterior approach involves laminectomy or laminoplasty with or without fusion. This approach is less technically demanding and is associated with fewer complications compared to the anterior approach. However, it can lead to issues such as C5 nerve root palsy, axial neck pain, and progressive cervical kyphosis.

This study retrospectively reviewed 44 patients with four-level CSM who underwent surgery between February 2012 and November 2015. Of these, 19 patients underwent anterior decompression and fusion, while 25 patients underwent posterior laminoplasty and instrumentation. The patients were followed up for an average of 4.8 years in the anterior group and 4.0 years in the posterior group. Preoperative and postoperative assessments included Japanese Orthopedic Association (JOA) scores, 36-item short form survey (SF-36) scores, and cervical alignment measurements using the Cobb angle at C2–C7.

The results showed no significant differences in JOA scores between the two groups preoperatively, immediately postoperatively, or at the last follow-up. However, the JOA scores significantly improved in both groups immediately postoperatively and at the last follow-up compared to their preoperative values. The recovery rate, which measures the improvement in JOA scores, was significantly higher in the anterior group both immediately postoperatively and at the last follow-up. Specifically, the recovery rate was 52% and 56% in the anterior group, compared to 35% and 43% in the posterior group, respectively. Additionally, the SF-36 score, which assesses general health and quality of life, was significantly higher in the anterior group at the last follow-up compared to the posterior group (69.4 vs. 61.7).

Radiological outcomes also favored the anterior approach. The Cobb angle, which measures cervical sagittal alignment, significantly improved in both groups immediately postoperatively and at the last follow-up compared to their preoperative values. However, the degree of improvement was significantly higher in the anterior group. The Cobb angle was 12.3° ± 4.2° immediately postoperatively and 12.4° ± 3.5° at the last follow-up in the anterior group, compared to 9.2° ± 3.6° and 9.0° ± 2.6° in the posterior group, respectively.

Complications varied between the two approaches. In the anterior group, three patients experienced temporary dysphagia, and one patient had transient dysphonia. In the posterior group, one patient suffered from C5 palsy, and four patients had persistent axial symptoms, which presented as stiffness and soreness. These complications highlight the potential drawbacks of each approach. While the anterior approach is associated with a higher risk of dysphagia and dysphonia, the posterior approach can lead to persistent axial pain, which can significantly impact a patient’s quality of life.

The study’s findings are consistent with previous research. For instance, Hirai et al. demonstrated that the anterior approach was associated with higher improvement in JOA scores and recovery rates at a 2-year follow-up. Similarly, a meta-analysis by Zhu et al. found that postoperative JOA scores were better in the anterior surgery group compared to the posterior group. However, other studies, such as those by Qian et al. and Luo et al., have shown no significant differences in neurological functional recovery rates between the two approaches.

One of the key factors influencing the choice of surgical approach is the patient’s cervical sagittal alignment. The anterior approach is particularly effective in restoring cervical lordosis, which has a strong influence on clinical outcomes. In contrast, the posterior approach can lead to decreased lordosis and worsened sagittal alignment, especially in patients with pre-existing kyphosis. However, this study found that laminoplasty and instrumented fusion could still improve sagittal alignment in patients with mild flexible kyphosis, defined as less than 15°.

When deciding on the surgical approach, other factors such as the patient’s age, health status, and the severity of cervical stenosis should also be considered. The anterior approach is generally recommended for younger and fitter patients due to the greater intraoperative time and blood loss associated with the procedure. In contrast, the posterior approach may be more suitable for elderly patients and those with significant pre-existing comorbidities.

In conclusion, both the anterior and posterior approaches are effective in treating four-level cervical spondylotic myelopathy. However, the anterior approach is associated with a higher recovery rate in JOA scores and better improvement in cervical sagittal alignment. The posterior approach, while less technically demanding, can lead to persistent axial pain, which may affect the patient’s quality of life. Therefore, the choice of surgical approach should be tailored to the individual patient’s condition, taking into account factors such as age, health status, and cervical alignment.

doi.org/10.1097/CM9.0000000000001146

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