UNASSIGNED: Severe traumatic fractures and dislocations of the lower cervical spine are usually accompanied by irreversible spinal cord injuries. Such patients rarely have mild or no neurological symptoms.
UNASSIGNED: We report three cases of severe lower cervical dislocation without spinal cord injury and discuss the mechanisms underlying this type of injury. All three patients had severe lower cervical dislocation, but their neurological symptoms were mild. In all cases, the fractures occurred at the bilateral junctions of the lamina and pedicle, resulting in severe cervical spondylolisthesis, whereas the posterior structure remained in place, thereby increasing the cross-sectional area of the spinal canal. After preoperative skull traction for a few days, the patients underwent anterior or combined anterior and posterior cervical surgeries. All surgeries were successfully completed and the patient\'s symptoms disappeared at the last follow-up.
UNASSIGNED: Severe traumatic dislocation of the lower cervical spine with an intact neurological status is rare in clinical practice. Pathological canal enlargement preserves neurological function, and the most commonly injured segment is C7. Preoperative traction for closed reduction remains controversial. We suggest that if no obvious anterior compression is observed, closed reduction should be pursued. Anterior or combined anterior and posterior cervical surgeries can provide rigid fixation with satisfactory results.

BACKGROUND: Complete fractures and dislocations of the lower cervical spine are usually associated with severe spinal cord injury. However, a very small number of patients do not have severe spinal cord injury symptoms, patients with normal muscle strength or only partial nerve root symptoms, known as \"lucky fracture dislocation\". The diagnosis and treatment of such patients is very difficult. Recently, we successfully treated one such patient.
METHODS: A 73-year-old male patient had multiple neck and body aches after trauma, but there was sensory movement in his limbs. However, preoperative cervical radiographs showed no significant abnormalities, and computed tomography (CT) and magnetic resonance imaging (MRI) confirmed complete fracture and dislocation of C7. Before operation, the halo frame was fixed traction, but the reduction was not successful. Finally, the fracture reduction and internal fixation were successfully performed by surgery. The postoperative pain of the patient was significantly relieved, and the sensory movement of the limbs was the same as before. Two years after surgery, the patient\'s left little finger and ulnar forearm shallow sensation recovered, and the right flexion muscle strength basically returned to normal.
CONCLUSIONS: This case suggests that when patients with trauma are encountered in the clinic, they should be carefully examined, and the presence of cervical fracture and dislocation should not be ignored because of the absence of neurological symptoms or mild symptoms. In addition, positioning during handling and surgery should be particularly avoided to increase the risk of paralysis.

To investigate the changes in neuromuscular function of anterior approach combined with subtotal vertebral body resection and titanium mesh cage (TMC) internal fixation for the old fracture-dislocated lower cervical spine. A 56-year-old female was admitted to the hospital with neck pain and numbness of the left upper extremity for 3 years due to a fall injury from a height, which worsened for 20 days. Although 3 years had passed, the patient still had significant left limb numbness and decreased muscle strength. Eventually, the patient was diagnosed with the old fracture-dislocation type injury of C6 and C7. C6 was II-degree anterior dislocation and the bilateral joint process was locked, C7 was burst fracture, and C5 was spinal cord segment injury. Then, the operation of the anterior approach combined with subtotal vertebral body resection and TMC internal fixation was performed under general anesthesia. Postoperative symptoms were significantly improved. And during five-year of follow-up, no adverse reactions and complications were reported. Although cervical fracture and dislocation combined with cervical spinal cord injury had persisted for many years, surgical treatment was necessary. The anterior approach combined with subtotal vertebral body resection and TMC internal fixation was desirable to improve neuromuscular function for the old fracture-dislocation of the lower cervical spine, which has some guiding effects on the clinical treatment.

OBJECTIVE: The surgical treatment of lower cervical facet dislocation is controversial. Great advancements on reduction techniques for lower cervical facet dislocation have been made in the past decades. However, there is no article reviewing all the reduction techniques yet. The aim is to review the evolution and advancements of the reduction techniques for lower cervical facet dislocation.
METHODS: The application of all reduction techniques for lower cervical facet dislocation, including closed reduction, anterior-only, posterior-only, and combined approach reduction, is reviewed and discussed. Recent advancements on the novel techniques of reduction are also described. The principles of various techniques for reduction of cervical facet dislocation are described in detail.
RESULTS: All reduction techniques are useful. The anterior-only surgical approach appears to be the most popular approach. Moreover, many novel or modified reduction and fixation methods have been introduced in recent years.
CONCLUSIONS: The selection of surgical approach depends on a combination of factors, including surgeon preference, patient factors, injury morphology, and inherent advantages and disadvantages of any given approach.

The biomechanical effects of intervertebral discs and facet joints degeneration on the cervical spine are essential to understanding the mechanisms of spinal disorders to improve pathological and clinical treatment. In this study, the biomechanical effects of a progressively degenerated C5-C6 segment on the human lower cervical spine are determined by a detailed simulation of intervertebral disc degeneration. A detailed asymmetric three-dimension intact finite element model was developed using computed tomography scan data of the human lower cervical spine (C3-C7). The intact finite element model was then modified at the C5-C6 segment to build three degenerated models, such as mild, moderate, and severe degeneration. The physiological compressive load 73.6 N, and moment 1 Nm were applied at the superior endplate of the vertebra C3, and the inferior endplate of the C7 vertebra was a constraint for all degrees of freedom. Range of motion, maximum von Mises stress in the annulus, intradiscal pressure, and facet joint force of the degenerated models were computed. With progressive degeneration in the C5-C6 segment, the range of motion of degenerated and normal segments decreases in all postures. Intradiscal pressure of the degenerated segment decreases but increases in normal segments of degenerated segment C5-C6, and facet joint forces increase at both degenerated and normal segments. This study emphasizes that the degenerated disc alters the degenerated and normal segments\' motion and loading patterns. The abnormal increase in facet joint force in the degenerated models threatened to accelerate the degeneration in the normal segments.

OBJECTIVE: Using the method of finite element analysis, to compare the biomechanical properties between the plate deviating from the long axis of the cervical spine and the standard placement of the plate in the anterior cervical fusion surgery.
METHODS: A healthy female volunteer was selected and CT scan (C1-T1) was performed. Using Mimics 19.0, Geomagic Studio 2015, Solidworks 2018, Ansys Workbench 17.2 to establish a lower cervical spine (C3-C7) model and to verify the reliability of the model. Subsequently, anterior cervical plates of different angles and lengths were placed to establish an anterior cervical discectomy fusion (ACDF) model. Applying 73.6 N axial pressure and 1 NM pure moment on C3 to make the model produce flexion, extension, lateral bending and rotation activities, observed the model stress cloud diagram and recorded the maximum stress value of the instrument and the intervertebral mobility.
RESULTS: The lower cervical spine (C3-C7) finite element model was established and verified against the published literature on the range of motion (ROM) of cervical spine. Effect of steel plate offset axis on stress distribution, maximum stress value and intervertebral ROM of internal fixation apparatus was minimal, and the mechanical effect of steel plate offset was less in double section steel plate than in single section steel plate.
CONCLUSIONS: Little effect on the mechanical stability of the cervical spine was anticipated when the anterior cervical plate was not perfectly aligned with the long axis of the cervical spine. If the tilt of the plate in clinical surgery is less than 20°, there is no need to readjust the position of the plate.

UNASSIGNED: To investigate the effectiveness of cervical pedicle screw implantation technique under regional method.
UNASSIGNED: The clinical data of 85 patients who met the selection criteria between April 2010 and May 2018 were retrospectively analyzed. There were 57 males and 28 females, aged 35-68 years, with an average of 57.6 years. Among them, there were 10 cases of ossification of posterior longitudinal ligament, 68 cases of cervical spondylosis with multilevel stenosis, 3 cases of cervical tumor, 1 case of congenital malformation, and 3 cases of cervical trauma; the lower cervical spine lesions involved C 3-C 7. Preoperative Frankel spinal cord injury grading: 2 cases of grade C, 51 cases of grade D, and 32 cases of grade E. Cervical pedicle screw implantation technique under regional method was performed with a total of 618 pedicle screws. Postoperative changes in neurological symptoms were observed; cervical mouth opening anteroposterior and lateral X-ray films and cervical CT examinations were performed to evaluate the pedicle screws position.
UNASSIGNED: The operation time was 2.5-4.0 hours, with an average of 3.0 hours. The intraoperative blood loss was 180-550 mL, with an average of 345 mL. No intraoperative vascular or nerve injury occurred. The patients with neurological symptoms were relieved to varying degrees. There were 2 cases of superficial incision infection after operation, the wound healed after enhanced dressing change. The postoperative hospital stay was 5-14 days, with an average of 8.4 days. At discharge, Frankel neurological grading was grade D in 26 patients and grade E in 59 patients. All the patients were followed up 6-24 months, with an average of 13 months. At last follow-up, cervical X-ray films showed the good pedicle screw fixation without loosening. Cervical CT evaluated the position of pedicle screws: 523 pedicle screws (84.7%) in grade Ⅰ, 80 (12.9%) in grade Ⅱ, and 15 (2.4%) in grade Ⅲ; the accuracy rate of the screw position was 97.6%.
UNASSIGNED: Cervical pedicle screw implantation technique under regional method can significantly improve the success rate of screw implantation. It is easy to operate, does not destroy the bone cortex, and has stable fixation.
UNASSIGNED: 探讨区域法下颈椎椎弓根钉植入技术的临床应用效果。.
UNASSIGNED: 回顾分析 2010 年 4 月—2018 年 5 月收治且符合选择标准的 85 例患者临床资料。男 57 例，女 28 例；年龄 35～68 岁，平均 57.6 岁。其中后纵韧带骨化 10 例，颈椎多节段退变椎管狭窄 68 例，颈椎肿瘤 3 例，先天发育畸形 1 例，颈椎外伤 3 例。病变部位累及 C 3～C 7。术前 Frankel 脊髓损伤分级：C 级 2 例，D 级 51 例，E 级 32 例。术中采用区域法下颈椎椎弓根钉植入技术，共植入 618 枚椎弓根钉。术后观察患者神经症状变化；行颈椎张口正侧位 X 线片及颈椎 CT 检查，评价椎弓根钉位置等级。.
UNASSIGNED: 手术时间 2.5～4.0 h，平均 3.0 h；术中出血量 180～550 mL，平均 345 mL。术中未出现血管、神经损伤，术前有神经症状患者术后均有不同程度好转。术后 2 例切口浅表感染，给予加强换药处理后切口愈合。术后住院时间 5～14 d，平均 8.4 d。出院时 Frankel 神经功能分级为 D 级 26 例、E 级 59 例。85 例患者均获随访，随访时间 6～24 个月，平均 13 个月。末次随访时颈椎 X 线片示椎弓根钉固定良好，无松动。颈椎 CT 评价椎弓根钉位置：Ⅰ级 523 枚（84.7%），Ⅱ级 80 枚（12.9%），Ⅲ级 15 枚（2.4%）；植钉准确率97.6%。.
UNASSIGNED: 区域法下颈椎椎弓根钉植入技术充分考虑到个体差异，可明显提高植钉成功率，操作简便，术中不破坏骨皮质且固定牢靠。.

暂无摘要。

BACKGROUND: Osteochondroma rarely occurs in the lower cervical spine in elderly patients, because it usually develops during skeletal growth and because of the limited mobility and lower stress in the lower cervical spine.
METHODS: A 63-year-old man complained of 3-month history of neck pain and a hard, palpable mass in the lower cervical spine. Plain radiography, computed tomography (CT) scan, and magnetic resonance imaging (MRI) revealed a bony mass arising from the left C5 transverse process with a medullary continuation and calcification and soft tissue displacement at the C4-C6 level. After the operation, the biopsy finding was consistent with osteochondroma, without malignant degeneration. We performed en bloc resection of the tumor, including the cartilaginous cap. The patient\'s symptoms improved after resection of the osteochondroma and demonstrated no recurrence of tumor at a 1-year follow-up.
CONCLUSIONS: This patient had a rare involvement of the transverse process without neurologic symptoms. Multiple imaging modalities, including plain radiography, CT, and MRI, play important roles in the diagnosis of osteochondroma. Complete surgical excision, including the cartilaginous cap, achieved a satisfactory surgical outcome and prevented possible recurrence.

OBJECTIVE: Besides the facet joints interlocking, the fibrous tissue or bony callus around the dislocated segments make the reduction for this kind of old injury to be more challenging and different from that of acute injuries. This study is aimed to present 4 cases of old subaxial cervical facet dislocations (SCFD) that were successfully treated with posterior unlocking under endoscopy followed by anterior decompression, reduction, and fixation.
METHODS: Between January 2017 and December 2017, 4 patients with old SCFD who underwent posterior unlocking of facet joints under endoscopy followed by anterior decompression, reduction, and fixation were enrolled. A cervical collar was prescribed for 4 weeks postoperatively. Postoperative follow-up evaluations were conducted at 2, 6, and 12 months, including neck visual analogue scale score and neck disability index, radiography, and computed tomography.
RESULTS: The operative time averaged 145 minutes (range, 130-155 minutes). No deterioration of neural function, major vessel rupture, or iatrogenic injury to esophagus occurred. Intraoperative blood loss averaged 45 mL (range, 40-50 mL). Hospital stay for all patients was only 4 days. The neck visual analogue scale score and neck disability index were improved at the final follow-up, and interbody fusion was satisfactory without any radiologic sign of instability or internal failure.
CONCLUSIONS: For patients with old SCFD, the unlocking of facet joints via the posterior approach under endoscopy followed by anterior decompression, reduction, and fixation is an alternative technique.