In the setting of trauma and degeneration, BSS occurs when the herniated cervical disc tissue is large and simultaneously protrudes laterally, as determined by the intrinsic anatomical characteristics of the spinal cord conduction tracts: compression of the corticospinal tracts in the anterior and lateral cords of the spinal cord, and of the thalamic tracts of the spinal cord, which cross within the spinal cord, results in ipsilateral motor dysfunction and contralateral warmth and nociception below the plane of the injured segment, respectively, and posterior cord involvement results in positional and vibratory sensory deficits. Since Stookey first reported a case of cervical disc herniation leading to BSS in 1928, a total of 39 such cases have been reported in the English literature, while some scholars in China have reported 25 cases since 2007.Jomin et al. counted the prevalence rate as 2.6%, but they did not provide a detailed number of cases, and Choi et al.[1] reported 0.21% (5/2350,) domestic Yang Haisong counted 4.0% (15/372). In the English literature, Jomin et al. reported 2 cases of cervical trauma resulting in nucleus pulposus herniation into the dural sac type of BSS, accounting for 5.1%. We hypothesize that on the basis of cervical disc degeneration, trauma can lead to rupture of the annulus fibrosus of the intervertebral disc, and protrusion of the nucleus pulposus under pressure, which can penetrate through the whole layer of the weaker posterior longitudinal ligament to reach the epidural space, and can separate from the nucleus pulposus tissue in the annulus fibrosus and then move in any direction within the spinal canal. The ossification of the posterior longitudinal ligament can cause the dural sac in contact with it to be subjected to chronic stress stimulation for a long period of time, resulting in a tight adhesion between the dural sac and the posterior longitudinal ligament and an increase in brittleness, and if the nucleus pulposus is strong enough, the nucleus pulposus can break through the dural sac and enter the spinal cord. People in China have the habit of seeking massage for neck and shoulder discomfort, so practitioners should be aware of this disease. For non-traumatic BSS, we analyzed the possible causes of this type of BSS: the patient has existing cervical degeneration, and under the stress of repeated cervical spine activities, the nucleus pulposus can prolapse across the posterior longitudinal ligament and lodge in the epidural space corresponding to the level of the intervertebral space. In patients with cervical spinal stenosis, the spinal cord is unable to tolerate the compression of the nucleus pulposus due to a significant reduction in the reserve space of the spinal canal, and symptoms are manifested. In our group of 8 patients, the ratio of the average preoperative vertebral canal loss diameter to the vertebral body loss diameter was 0.72 but less than 0.75, suggesting the presence of spinal stenosis. In the clinical data of 39 cases reported in the English literature, the mean age at onset of the patients was 47 years (25-73 years), with 28 males and 11 females.Thirty-four cases were single-space disc herniations, five cases were 2-space disc herniations, and no 3-space disc herniations leading to BSS were reported. The most affected segment was C5/6 (53.8%), and the rest were C3/4 (17.9%), C4/5 (17.9%), C6/7 (17.9%), and C2/3 (5.1%) in that order. Cervical disc herniation was most common in the epidural type of herniation, and a total of 10 cases (29%) of intradural herniation were reported. In our group, all 8 cases were observed as epidural type herniation on preoperative MRI, and intraoperatively, all of these free nuclei were confirmed to have penetrated the posterior longitudinal ligament, but there was no intradural herniation. The history of epidural-type BSS ranged from 1 to 18 months, whereas that of intradural-type BSS ranged from 1 day to 2 months. Because the nucleus pulposus herniated into the intradural directly compresses and injures the spinal cord, the literature reports that this type of BSS has a poorer clinical outcome than the epidural type of BSS. All cervical disc herniations are paracentral in MRI cross-sectional view, and central herniations do not produce BSS symptoms. Because the herniated cervical discs mainly compressed the spinal cord rather than the nerve roots, only 9 patients showed radicular pain symptoms. In addition, clinically, soft cervical disc herniation could not cause complete loss of function of the spinal cord, therefore, it did not show typical BSS: 1) usually the lateral corticospinal tracts and thalamic tracts on the herniated side were involved, while the posterior cord was not involved, so none of the clinical cases showed complete loss of positional and vibration senses; 2) the lateral corticospinal tracts were compressed, but the function was not completely lost; the muscle strength of the limbs on the side of the spinal cord compression was 2 to 4 levels in 8 cases of this group; the muscle strength was 2 to 4 levels in the limbs on the side of spinal cord compression. In this group, the muscle strength of the limbs on the side of spinal cord compression varied from 2 to 4, and there was no case of 0 level of muscle strength on the damaged side when the spinal cord was completely cut in half.3) Because the clinical manifestations of all the cases were not typical of BSS, they were easily misdiagnosed as myelitis, multiple sclerosis, and neurological diseases such as subacute co-morbidities, which would result in the loss of optimal treatment time before cervical spinal cord MRI was carried out. Cervical disc herniation leads to severe compression of one half of the spinal cord, and spinal cord function is obviously impaired. Therefore, early surgical decompression is required to maximize the recovery of spinal cord function after the diagnosis is clear. Although there are reports that cervical disc herniation is naturally absorbed by conservative treatment, Shimomura et al. showed in a retrospective study of 56 patients with spinal cord cervical spondylosis who were not treated surgically that good clinical outcomes could be achieved by conservative treatment in patients with mild (preoperative JOA scores of 13-17) spinal cord cervical spondylosis, and that in patients who had annular compression of the spinal cord and loss of the subdural space in the axial plane of MRI, the spinal cord could be decompressed in the axial plane of MRI. Surgery is required for mild patients with spinal cord compression and loss of the subdural space on the axial plane of MRI. In our group, 8 patients had a preoperative JOA score of 10 or less, so conservative treatment was not appropriate and surgical treatment was preferred. Similarly, most of the literature supports early surgical decompression therapy for BSS to save spinal cord function, and even some of the trauma-induced BSS requires emergency surgical treatment. Since the nucleus pulposus of BSS compresses the spinal cord from the front, surgical decompression by anterior approach can directly remove the compression-causing material and reduce the compression completely. Early on, some scholars used posterior laminoplasty for indirect decompression, but most scholars believed that posterior indirect decompression could not remove the compressor, and the “anchoring effect” of cervical nerve roots and dentate ligament on the spinal cord made the spinal cord move backward to a limited extent, which affected the clinical efficacy of posterior surgery. Lee et al. used anterior foraminotomy, drilling a hole (5×8 mm in size) in the medial aspect of the hook vertebral joint and removing the protruding nucleus pulposus minimally invasively under the microscope. Because of its high technical requirements, it is difficult to popularize the operation. Most of the literature reports the use of anterior transforaminal decompression (61.5%) or subtotal vertebral body resection, decompression and implant fusion and internal fixation (10.2%) in the treatment of BSS.Usually, the selection of these two surgical procedures should be guided by the following principles: 1) in the case of a single-space herniation, with well-developed vertebral canal and insignificant bony proliferation, a single-space decompression and fusion and fixation can be feasible in order to preserve the cervical spine motion segments; 2) in the case of a disc herniation with two or more spaces, the cervical vertebrae can be treated by the following procedures (2) For herniated discs with two or more interspaces, cervical degeneration and osteophyte proliferation is obvious, and the nucleus pulposus is large and breaks through the posterior longitudinal ligament and is free from the posterior longitudinal ligament to the posterior part of the vertebral body, or herniated into the dural sac, and it is difficult to remove the nucleus pulposus via the vertebral body with a limited surgical field, sub-total resection of the vertebral body for decompression and fusion fixation can be used. Overall, patients had a satisfactory clinical recovery after surgical decompression, with a few remaining motor and sensory deficits. The literature reported that 16 of 29 patients (55%) with epidural herniation achieved complete recovery, while 3 of 10 patients (30%) with intradural herniation achieved complete recovery. In conclusion, BSS caused by cervical disc herniation is relatively rare in clinical practice, and the clinical manifestations of patients are not very typical. Therefore, it is advisable for such patients to undergo early cervical MRI and differentiate from related neurological disorders, and then undergo anterior Nucleus Pulposus removal, decompression and internal fixation after early diagnosis, and complete decompression is the key to the success of the surgical treatment.