Effectiveness of different surgical methods in the treatment of acute central cord syndrome without fractures and dislocations of the cervical spine

1.Introduction

Cervical spinal injury (CSI) without fractures or dislocations is a condition usually seen in the young and middle-aged population, accounting for about 45% of all cases [1], in which fractures or dislocations of the cervical spine are absent under computed tomography (CT), X-ray, or magnetic resonance imaging (MRI). However, it demonstrates acute CSI symptoms that are detectable by MRI. Patients mainly present with a more pronounced motor nerve impairment in the upper extremity than the lower extremity, loss of sensation, and sphincter dysfunction below the plane of injury, with the central cord syndrome (CCS) being more common. Clinically, CSI with fractures or dislocations can be detected by conventional imaging, and the efficiency of surgical treatment for it is considered favorable. Nevertheless, consensus on the treatment for CCS without fractures or dislocations has not yet been developed [1, 2, 3, 4, 5, 6, 7, 8, 9]. CSI can be treated with anterior cervical discectomy and fusion or posterior cervical laminectomy. Anterior cervical discectomy and fusion features complex anatomical structures at the surgical site, a small surgical field of view, difficult surgery, and high early complication rates (2.4%–36.6%) [1]. In posterior cervical laminectomy, the cervical spinal cord is indirectly decompressed ventrally by enlarging the cervical spinal canal and moving the spinal cord posteriorly through the “bowstring effect” [2], but patients may experience postoperative axial symptoms [2, 3]. The choice of surgical approach (anterior, posterior, or combined anterior-posterior approach) depends mainly on the imaging of the cervical spine in the sagittal plane, the extent of the lesion, the site of compression, the degree of preoperative neck pain, and the surgical history of patients [1, 2, 3]. Treatment of non-fractured dislocated cervical spinal cord injuries decompresses the compressed spinal cord, reconstructs the spine, and ensures the stability of the cervical spine, so the determination of spinal cord compression and cervical spine stability is a key reference factor in the evaluation of surgical indications. The selection of a reasonable surgical approach to achieve complete decompression of the spinal canal contributes to a favorable treatment outcome [6]. The choice of the anterior and posterior approaches for surgery should be based on the principle of accurate and effective decompression of the spinal cord with compression, and anterior surgery is more appropriate in most cases because of the presence of cervical disc compression [4, 7]. Anterior surgery can be adopted for those with cervical disc herniation compressing the spinal cord or the dural sac leading to spinal stenosis, without continuous posterior longitudinal ligament ossification and hypertrophy of the ligamentum flavum. In the case of mild disc bulge, good spinal canal volume, and no significant interference with cerebrospinal fluid imaging between the disc and the spinal cord, the bulging disc can be considered not to constitute a spinal cord compressor. Hypertrophy of the ligamentum flavum and narrowing of the cervical spinal canal constituting a spinal cord compressor require posterior surgical canal enlargement for treatment, and posterior decompression can be used in the case of continuous posterior longitudinal ligament ossification that precludes anterior surgery. The ASIA issued the neurological classification of spinal cord injuries (ASIA criteria) in 1982, and its fourth edition (1992) was adopted by the International Spinal Cord Society (ISCS) and was recognized by the International Spinal Cord Society (ISCoS) as the international standard for neurological classification of spinal cord in-jury (ISNCSCI) [2]. The sixth edition of the ASIA criteria (2000) included basic concepts, neurological scores, ASIA impairment scale (AIS), and clinical syndromes, and introduced quantitative indicators [3, 4], and are widely used worldwide [5].

2.Material and methods

3.Results

4.Discussion

Acute central cord syndrome is a specific type of spinal cord injury caused by compression of the central cervical spinal cord from the anterior and posterior cervical spinal canal. The disease is more frequently seen in the young and middle-aged population and is characterized by the typical acute cervical spinal injury without fractured and dislocated cervical vertebrae, with complex specific manifestations. Its etiology is poorly understood. As patients with mild conditions of the disease may recover spontaneously after conservative treatment [19, 20, 21], the application of surgical methods for ACSS remains controversial, and conservative treatment has been more frequently adopted in previous practice. However, results of the follow-up statistics by Ratre et al. showed no relief or even worsening of symptoms in some cases [22, 23, 24]. With the development of MRI technology, it has been found that most patients with CCS had severe soft tissue injury around the spinal cord and some underlying lesions of spinal canal compression, which necessitates surgical treatment [25, 26]. Results of the present study showed significant improvement in the ASIA classification, ASIA motor scores, and sensory scores after surgery (P< 0.001), and patients in both groups were satisfied with the surgical methods without significant differences (P= 0.659). A possible explanation can be that the surgery reduces the edema of the spinal cord and its internal pressure, improves blood circulation, and lessens or avoids secondary damage to the spinal cord, thereby accelerating early recovery of spinal cord function and increasing patient satisfaction, which is similar to the results by Zhu et al. [27]. After the onset of CSI, tissue hemorrhage, edema, and dural adhesions lead to increased intradural pressure in the spinal canal and spinal cord parenchyma, causing an ischemic and hypoxic pathophysiologic process that accelerates the cascade response of secondary spinal cord injury. Proper timing of surgery and appropriate surgical decompression strategies can reduce the associated secondary injuries. However, there is still debate about the safety and efficacy of decompression surgery. Considering the impact of the degree and severity of nerve injury on the timing of surgery, clinical CSI subgroups may potentially benefit from early surgery. Early decompression should be considered for patients with incomplete cervical CSI, and patient age should be excluded from the criteria for early surgery. The optimal time point for early surgery should not be limited by progression and is encouraged to be determined by a thorough examination of the patient’s condition and the shortest time for stabilization of the patient’s status. Therefore, a variety of circumstances, such as standardized decompression methods, indications, and timing of surgery, should be considered to ensure the effectiveness and safety of early surgical interventions and to promote functional recovery of residual nerve tissue. No significant differences between the anterior cervical discectomy and fusion and the posterior cervical laminectomy for patients with ACCS in terms of ASIA classification, ASIA motor scores, and sensory scores were found. It was shown that the complication rate of posterior cervical spine surgery is lower than that of anterior surgery in patients with CSI [9]. The limitations of this study include the lack of studies on complications and the small number of patients included. In the future, a multicenter study with a larger number of patients will be conducted to obtain more clinical data. Moreover, elderly patients were not covered in this study. The elderly population is prone to traumatic cervical medullary injuries due to physical deterioration, poor coordination, and poor muscle protection and compensatory capacity, and therefore cervical medullary injuries in the elderly population require increasing attention. ACSS, as one of the most common types of incomplete cervical medullary injury, features an incidence of about 70% [1]. Because elderly patients usually have degenerative cervical spine diseases and different degrees of cervical spinal cord compression and other pathological bases in the spinal canal, they are more susceptible to spinal cord compression after trauma. Elderly patients with ACCS, even without cervical fracture-dislocation, are often associated with injury to the anterior cervical ligament, or the disc-anterior longitudinal ligament complex, leading to potential cervical instability [4, 5, 6], which is an absolute indication for surgical treatment. With the development of tissue engineering and medical devices, the self-locking zero-tangential interbody fusion ROI-C was designed to be used in anterior cervical decompression fusion surgery. Currently, the ROI-C fusion device has been widely used in the surgical treatment of cervical degenerative diseases with satisfactory results due to its simple operation, high time efficiency, and good treatment effects.

5.Conclusion

Both anterior cervical discectomy and fusion and posterior cervical laminectomy can improve the ASIA classification, ASIA motor scores, and sensory scores of ACCS patients without fractures or dislocations of the cervical spine. Therefore, surgical methods should be adopted based on the patients’ conditions.