Objective To study operative methods of treating upper cervical spine instability without injury. Methods Twentythree cases were treated by internal fixation with autologous bone grafts. Atlantoaxial arthrodesis were performed in 10 cases with Apofix interlaminar clamp(5 cases), Atlas cable system(3 cases) and Brookes(2 cases). Occipitocervical fusion were performed in the other 13 cases by using of CD-cervical(3 cases), Cervifix(8 cases) and Ustick fixation(2cases). Results All the 23 cases were followed up for 2.5 years in average (ranged from 6 months to 5 years). Solid arthrodesis was obtained in all 23 cases . Six months after operation, of the 20 cases with preoperation nervous lesion, improvement was achieved in 16 cases. According to JOA standard and Hirabashiformula,the rate of improvement was 27.1%.Conclusion Posterior fusion is recommended for upper cervical unstability.
Objective To evaluate the clinical effect of Halo-vest in treatment of unstable upper cervical spine. Methods From March 1997 to October 2002, 16 cases of unstable upper cervical spineswere treated and immobilized by Halovest, aged from 14 to 53 years. There were 3 cases of isolated Jefferson fractures, 4 cases of isolated Hangman fractures and 1 case of Anderson type Ⅱ fracture. The 8 cases were immobilized for 3-4 months by Halovest. There were 3 cases of old odontoid fractures with dislocations treated by occipitocervical plate fixation and fusion, 1 case of C1 malignant tumor by posterior resection and internal fixation, 2 cases of C2 malignant tumor by anterior resection, fusion, and internal fixation; these cases were immobilized by Halo-vest during surgery. There were 1 case of C2,3 tuberculosis were treated by anterior debridement and fusion, and 1 case of gooseneck deformity by anterior decompression, fusion and screw fixation after resection of C2-7 , the 2 cases were immobilized for 3 months by Halo-vest.Of 16 cases, there were 8 cases accompanied with spinal cord syndrome. Results Fifteen cases were followed up 6 months to 5 years. Anterior arch ununion and posteriorarch osseous healing occurred in 1 case of Jefferson fracture. Other fractures and embedded bones became osseous fusion. One case of C2 malignant tumorrecurred 8 months after operation. Spinal cord syndrome of all patients disappeared. Conclusion Halo-vest immobilization is an effective method for conservative treatment and stable reconstruction of unstable upper cervical spine.
A comprehensive, geometrically accurate, nonlinear C0-T1 three-dimensional finite element (FE) model was developed for the biomechanical study of human cervical spine and related disorders. The model was developed with anatomic detail from the computed tomography (CT) images of a 46-year old female healthy volunteer, and applied the finite element model processing softwares such as MIMICS13.1, Hypermesh11.0, Abaqus 6.12-1, etc., for developing, preprocessing, calculating and analysing sequentially. The stress concentration region and the range of motion (ROM) of each vertebral level under axial rotation, flexion, extension, and lateral bending under physiologic static loadings were observed and recorded. The model was proven reliable, which was validated with the range of motion in previous published literatures. The model predicted the front and side parts of the foramen magnum and contralateral pedicle and facet was the stress concentration region under physiological loads of the upper spine and the lower spine, respectively. The development of this comprehensive, geometrically accurate, nonlinear cervical spine FE model could provide an ideal platform for theoretical biomechanical study of human cervical spine and related disorders.
ObjectiveTo investigate the effectiveness of cervical pedicle screw implantation technique under regional method.MethodsThe 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 C3-C7. 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.ResultsThe 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%.ConclusionCervical 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.
This study aims to investigate the range of motion (ROM) and the stress variation in the intervertebral disc and the vertebral body on adjacent segments and the influence of force transmission mode after the dynamic cervical implant (DCI) surgery. Two types of surgery, DCI implantation and interbody fusion were used to establish the finite element model of the cervical C5, 6 segment degeneration treatment. The ROM and the adjacent discs and vertebral body stresses of two procedures under flexion, extension, lateral bending and axial rotation working conditions were analyzed. The results showed that ROM of the surgical segment in DCI model was well preserved and could restore to the normal ROM distributions (reduction of the amplitude was less than 25%), and the kinetic characteristics of adjacent segments was less affected. In fusion surgery model, however, ROM of the surgical segment was reduced by 86%-91%, while ROM, disc stress and vertebral stress of adjacent segments were increased significantly, and stress of the C5 vertebral body was increased up to 171.21%. Therefore DCI surgery has relatively small influence on cervical ROM and stress. The study provides a theoretical basis for DCI and fusion surgery in clinic.
Objective To explore the surgical feasibil ity and cl inical outcome of transpedicle screw fixation in treatment of atlantoaxial instabil ity and dislocation. Methods From January 2007 to June 2009, 16 patients with atlantoaxial instabil ity and dislocation were treated with transpedicle screw fixation. There were 13 males and 3 females, with a mean age of 42 years (range, 24-61 years). The transpedicle screw fixation was employed in 5 patients with old odontoid fracture (4 of Anderson type II and 1 of type III), in 4 patients with fresh odontoid fracture, in 4 patients with traumatic disruption of transverse atlantal l igament, and in 3 patients with congenital odontoid disconnection for atlantoaxial instabil ity. All patients had symptoms of cervical pain and l imition of cervical motion, 10 patients compl icated by dyscinesia and hypoesthesia of extremities. The Japanese Orthopaedic Association (JOA) score before operation was from 5 to 13, with an average of 8.5. The image examination showed atlantoaxial instabil ity or dislocation in all patients. Granulated autogenous il ium (20-30 g) was placed onto the surface of the posterior arches of both atlas and axis in some patients with old fracture of odontoid process or disruption of transverse atlantal l igament. Results The mean operative time and bleeding amount were 1.6 hours (1.2-2.5 hours) and 100 mL (50-200 mL), respectively. All the incision healed by first intension. All patients were followed up for 3-18 months, with an average of 11.5 months. The JOA score 3 months after operation was from 12 to 17, with an average of 14.2. All screws were successfully placed in atlas and axis. No postoperative compl ications such as vertebral artery injury, dural rupture, exacerbation of neurological symptoms, wound infection, and broken srews were observed in 16 cases. Postoperative radiograph and CT showed that only one screw penetrated into vertebral canal, but there was no neurological symptoms. Bony fusion was observed after 6 to 18 months of operation, and atlantoaxial rotational function in all patients restored satisfactorily, but axial rotation was partially lost. Conclusion Transpedicle screw fixation in upper cervical spine for treatment of atlantoaxial instabil ity and dislocation is safe and rel iable
ObjectiveTo introduce and interpret ABCD classification system for subaxial cervical spine injury. MethodsThe literature related to subaxial cervical spine injury classification system was extensively reviewed, analyzed, and summarized so as to introduce the ABCD classification system. ResultsThe ABCD classification system for subaxial cervical spine injury consists of 3 parts. The first part of the proposed classification is an anatomical descri ption of the injury; it del ivers the information whether injury is bony, ligamentous, or a combined one. The second part is the classification of nerve function, spinal stenosis, and spinal instabil ity. The last part is optional and denotes radiological examination which is used to define injury type. Several letters have been used for simplicity to del iver the largest amount of information. And a treatment algorithm based on the proposed classification is suggested. ConclusionThe ABCD classification system is proposed for simplification. However further evaluation of this classification is needed.
Objective To investigate the effect of ultrasonic bone curette in anterior cervical spine surgery. MethodsA clinical data of 63 patients with cervical spondylosis who were admitted between September 2019 and June 2021 and met the selection criteria was retrospectively analyzed. Among them, 32 cases were operated with conventional instruments (group A) and 31 cases with ultrasonic bone curette (group B). There was no significant difference between the two groups (P>0.05) in gender, age, surgical procedure, surgical segment and number of occupied cervical space, disease type and duration, comorbidities, and preoperative Japanese Orthopaedic Association (JOA) score, cervical dysfunction index (NDI), and pain visual analogue scale (VAS) score. The operation time, intraoperative bleeding, postoperative drainage, postoperative hospital stay, and the occurrence of postoperative complications were recorded in both groups. Before operation and at 1, 3, and 6 months after operation, the JOA score and NDI were used to evaluate the function and the postoperative JOA improvement rate was calculated, and VAS score was used to evaluate the pain improvement. The anteroposterior and lateral cervical X-ray films were taken at 1, 3, and 6 months after operation to observe whether there was any significant loosening and displacement of internal fixators. ResultsCompared with group A, group B had shorter operation time and postoperative hospital stay, less intraoperative bleeding and postoperative drainage, and the differences were significant (P<0.05). All incisions healed by first intention in the two groups, and postoperative complications occurred in 5 cases (15.6%) in group A and 2 cases (6.5%) in group B, showing no significant difference (P>0.05). All patients were followed up 6-12 months (mean, 7.9 months). The JOA score and improvement rate gradually increased in groups A and B after operation, while the VAS score and NDI gradually decreased. There was no significant difference in VAS score between 3 months and 1 month in group B (P>0.05), and there were significant differences between the other time points of each indicator in the two groups (P<0.05). At 1, 3, and 6 months after operation, the JOA score and improvement rate in group B were better than those in group A (P<0.05). X-ray films examination showed that there was no screw loosening or titanium plate displacement in the two groups after operation, and the intervertebral cage or titanium mesh significantly sank. ConclusionCompared with traditional instruments, the use of ultrasonic bone curette assisted osteotomy in anterior cervical spine surgery has the advantages of shorter operation time, less intraoperative bleeding, less postoperative drainage, and shorter hospital stay.
ObjectiveTo measure anatomical parameters related to cervical uncovertebral joint and provide data support for the design of uncovertebral joint fusion cage.MethodsAccording to the inclusion and exclusion criteria, raw DICOM data of cervical CT scan in 60 patients (30 males and 30 females, aged 39-60 years) were obtained, then the three-dimensional cervical spine model was reconstructed for anatomical measurement by using the Mimics19.0 software. The height of the uncinate process, the length of the uncinate process, the width of the uncinate process, and the length of the uncovertebral joint in the intervertebral foramen region were measured bilaterally from C3 to C7. The anterior and posterior distances between the uncinate processes were measured from C3 to C7. The height of the uncovertebral joint space, the central height of the intervertebral disc space, and the depth of the intervertebral disc space were also measured from C2, 3 to C6, 7. The mean, standard deviation, maximum, and minimum were calculated by using the SPSS22.0 statistical software for the design of uncovertebral joint fusion cage.ResultsThe height of the uncinate process, the length of the uncinate process, the width of the uncinate process, and the length of the uncovertebral joint in the intervertebral foramen region of C3-C7 and the height of the uncovertebral joint space of C2, 3-C6, 7 showed no significant difference between two sides (P>0.05). The height of the uncovertebral joint space also had no significant difference between females and males (P>0.05). The anterior distances between the uncinate processes of C3-C7 were significantly larger than the posterior distances between the uncinate processes (P<0.05), the uncovertebral joint presented a posterior cohesive shape. The central height of the intervertebral disc space in male group was slightly higher than that in female group, and the differences were significant (P<0.05) at C2, 3 and C5, 6; the depth of the intervertebral disc space in male group was significantly higher than that in female group (P<0.05). The central height of the intervertebral disc space was (4.94±0.49) mm (range, 3.81-5.90 mm), the depth of the intervertebral disc space was (15.78±1.23) mm (range, 12.94-18.85 mm), the anterior and posterior distances between the uncinate processes were (17.19±2.39) mm (range, 13.39-24.63 mm) and (10.84±2.12) mm (range, 7.19-16.64 mm), respectively. According to the results of the anatomical research, the height of the uncovertebral joint fusion cage was designed as 5, 6, 7, and 8 mm; the depth of the uncovertebral joint fusion cage was designed as 12, 13, 14, 15, and 16 mm; the width of the uncovertebral joint fusion cage was designed as 14-18 mm; and the two wings are designed as arc-shape with 2 and 3 mm in width.ConclusionThere are certain differences in the anatomical parameters of the uncovertebral joint between different segments. The uncovertebral joint fusion cage that designed based on the results of anatomical research is suitable for most patients.
This article reviews the progress of biomechanical studies on anterior cervical fusion and nonfusion surgery in recent years. The similarities and differences between animal and human cervical spines as well as the major three biomechanical test methods are introduced. Major progresses of biomechanical evaluation in anterior cervical fusion and nonfusion devices, hybrid surgery, coupled motion and biomechanical parameters, such as the instant center of rotation, are classified and summarized. Future development of loading method, multilevel hybrid surgery and coupling character are also discussed.