Yuxiao Deng

Clinical and radiography results of mini-plate fixation compared to suture suspensory fixation in cervical laminoplasty: A five-year follow-up study.

OBJECTIVES Lamina closure is the most common reason for failure of unilateral open-door laminoplasty. Mini-plate fixation was designed to solve such problem. We assessed the clinical outcomes and radiography results of mini-plate fixation by comparing it with suture suspension fixation. PATIENTS AND METHODS This prospective study enrolled 57 patients with multi-segment cervical spondylotic myelopathy between January 2008 and March 2010. Thirty-four patients underwent laminoplasty with mini-plate fixation (mini-plate group) whereas 23 patients underwent laminoplasty with suture suspension fixation (suture group). The neurological function was measured with the Japanese Orthopedic Association (JOA) score. Cervical range of motion (ROM), C2-7 angle, and the spinal canal expansive parameters (anteroposterior diameter, Pavlovs ratio, cross-sectional area, and open angles) were evaluated. RESULTS The mean follow-up time was 64 (60-82) months. There were no significant differences in preoperative JOA scores (p=0.191), postoperative JOA scores (p=0.700), preoperative cervical ROM (p=0.315) and preoperative C2-7 angle (p=0.074) between the two groups. Both groups had significant postoperative JOA improvement (p<0.05). The mini-plate group had larger cervical ROM (p=0.041) and C2-7 angle (p=0.040) than the suture group at the final follow-up. Both groups showed significant improvement in the spinal canal expansive parameters immediately after the surgery. In the suture group, the parameters, such as anteroposterior diameter, Pavlovs ratio, cross-sectional area, and open angles, decreased along with time, mainly within the first 6 months following the operation. In the mini-plate group, these parameters remained unchanged. The spinal canal expansive parameters between the 2 groups were not significantly different immediately following the operation, but were significantly different at the final follow-up (p<0.05). Three patients in the suture group displayed neurological deterioration due to lamina reclosure. CONCLUSIONS Laminoplasty by mini-plate fixation preserved more cervical ROM and better cervical alignment, maintained cervical spine canal expansive stability and effectively avoided lamina reclosure for a long-term follow-up.

Multivariate Analysis of Factors Associated With Axial Symptoms in Unilateral Expansive Open-Door Cervical Laminoplasty With Miniplate Fixation.

AbstractRetrospective case–control study.Unilateral expansive open-door cervical laminoplasty with miniplate fixation is an efficient and increasing popular surgery for multilevel cervical spondylotic myelopathy. Axial symptoms are the most frequent complaints after cervical laminoplasty. But the mechanisms have not been fully clarified yet.The objective of this study is to compare the clinical and radiologic data between patients with or without axial symptoms and to investigate the factors associated with axial symptoms by multivariate analysis in cervical laminoplasty with miniplate fixation.A total of 129 patients who underwent cervical laminoplasty with miniplate fixation were comprised from August 2009 to March 2014. Patients were grouped according to whether they suffered from postoperative axial symptoms (PA) or not (NA). The clinical data including gender, age, duration of symptoms, diagnosis type, medical comorbidity, operative level, blood loss, operative time, pre- and post-Japanese Orthopedic Association (JOA) score, JOA recovery rates, and other complications were recorded. The radiologic data including cervical canal diameter, C2–7 Cobb angle, cervical range of motion (ROM), cross-sectional area, open angle, hinge union, and facet joint destroyed would be measured according to X-ray plain and CT scan images. The univariate analysis and multivariate logistic regression analysis were performed.There were 39 patients in PA group and 90 patients in NA group. Both groups gained significant JOA improvement postoperatively (P < 0.05). The preoperative neck pain (P = 0.048), negative change of cervical ROM (P = 0.018), and facet joints destroyed (P = 0.022) were significant different between the 2 groups. There were no significant differences for other clinical and radiography parameters between the groups (P > 0.05). The multivariate analysis showed that the negative change of cervical ROM (OR = 1.062, P = 0.047) and facet joints destroyed (OR = 0.661, P = 0.024) were related to axial symptoms.The change of cervical ROM and facet joints destroyed by miniscrews might be associated with axial symptoms after cervical laminoplasty with miniplate fixation. Cervical spine surgeons should carefully operate to decrease the injury of posterior musculature structure and protect the facet joints.

Comparison of the incidence of patient-reported post-operative dysphagia between ACDF with a traditional anterior plate and artificial cervical disc replacement

PURPOSE Compared with anterior cervical discectomy and fusion (ACDF), cervical disc replacement (CDR) has provided satisfactory clinical results. The incidence of post-operative dysphagia between ACDF with a traditional anterior plate and CDR remains controversial. Considering the limited studies and knowledge in this area, a retrospective study focusing on post-operative dysphagia was conducted. METHODS The Bazaz grading system was used to assess the severity of dysphagia at post-operative intervals including 1 week, 1 month, 3 months, 6 months, 12 months and 24 months respectively. The Chi-square test, Student t-test, Mann-Whitney U tests and Ordinal Logistic regression were used for data analysis when appropriate. Statistical significance was accepted at a probability value of <0.05. RESULTS Two hundred and thirty-one patients in the CDR group and one hundred and fifty-eight patients in Plate group were included in this study. The total incidences of dysphagia in the CDR and plate group were 36.58% and 60.43% at one week, 29.27% and 38.85% at one month, 21.95% and 31.65% at three months, 6.83% and 17.99% at six months, 5.85% and 14.39% at 12 months, and 4.39% and 10.07% at the final follow-up respectively (All P<0.05, Mann-Whitney U test). Ordinal Logistic regression analysis showed that female patients, two-level surgery, C4/5 surgery, and anterior cervical plating were significant risk factors for post-operative dysphagia (all P<0.05). CONCLUSION Comparing ACDF with a plate, CDR with a Prestige LP can significantly reduce both transient and persistent post-operative dysphagia. Female patients, two-level surgery, C4/5 surgery and anterior cervical plating were associated with a higher incidence of dysphagia. Future prospective, randomized, controlled studies are needed to further validate these findings.

Use of rapid prototyping drill template for the expansive open door laminoplasty: A cadaveric study.

OBJECTIVE Trough preparation is a technically demanding yet critical procedure for successful expansive open door laminoplasty (EOLP), requiring both proper position and appropriate bone removal. We aimed to use the specific rapid prototyping drill template to achieve such requirement. METHODS The 3D model of the cadaveric cervical spine was reconstructed using the Mimics 17.0 and Geomagic Studio 12.0 software. The drilling template was designed in the 3-Matic software. The trough position was simulated at the medial margin of the facet joint. Two holders were designed on both sides. On the open side, the holder would just allow the drill penetrate the ventral cortex of the lamina. On the hinge side, the holder was designed to keep the ventral cortex of the lamina intact. One orthopedic resident performed the surgery using the rapid prototyping drill template on four cadavers (template group). A control group of four cadavers were operated upon without the use of the template. RESULTS The deviation of the final trough position from the simulated trough position was 0.18mm±0.51mm in the template group. All the troughs in the template group and 40% of the troughs in the control group were at the medial side of the facet joint. The complete hinge fracture rate was 5% in the template group, significantly lower than that (55%) in the control group (P=0.01). CONCLUSION The rapid prototyping drill template could help the surgeon accomplish proper trough position and appropriate bone removal in EOLP on the cadaveric cervical spine.

Posterior distraction reduction and occipitocervical fixation for the treatment of basilar invagination and atlantoaxial dislocation

OBJECT To introduce a novel distraction technique for the treatment of basilar invagination (BI) and atlantoaxial dislocation (AAD) via a posterior-only approach. METHODS Twenty-one consecutive patients with BI and AAD who underwent posterior distraction reduction and occipitocervical fixation between January 2009 and June 2013 were enrolled in the present study. This novel distraction technique included two steps. First, the distraction between the occipitocervical junction of the rod (OCJR) and the occipital screws was performed to achieve horizontal and partial vertical reduction. Secondly, the distraction was performed between the C2 screws and OCJR to achieve complete vertical reduction. The pre- and postoperative JOA score, the extent of reduction, the fusion status, and the complications were recorded and analyzed. RESULTS The mean follow-up was 18.3 months with a range of 10-32 months. No patient incurred neurovascular injury during surgery. The mean JOA score at the last follow-up (15.4) showed significant improvement (P<0.01) compared with the pre-operative parameters (11.2). Complete horizontal reduction was achieved in 18 patients (85.7%), and complete vertical reduction was achieved in 17 patients (80.9%). The rest patients are all received greater than 50% horizontal and vertical reduction. Solid fusion was achieved in 20 patients (95.2%). Mild dysphagia was observed in two patients. One patient suffered from postoperative fever and pulmonary infection. CONCLUSION This novel distraction technique may provide satisfactory reduction via a posterior-only approach without exposure of the C1/2 facet joint. Therefore, it is a safe and effective method for the treatment of BI with AAD.

Clinical and radiographic comparison of cervical disc arthroplasty with Prestige-LP Disc and anterior cervical fusion: A minimum 6-year follow-up study

OBJECTIVES To retrospectively compare the long-term clinical and radiographic outcomes of cervical disc arthroplasty (CDA) with Prestige-LP Disc and anterior cervical discectomy and fusion (ACDF) for single-level cervical degenerative disc disease. PATIENTS AND METHODS Ninety-eight patients (45 CDA and 53 ACDF) with a minimum 6-year follow-up were included. Clinical evaluations included Japanese Orthopedic Association (JOA), visual analogue scale (VAS), and Neck Disability Index (NDI) scores. Radiographic evaluations included sagittal alignment, range of motion (ROM) at the index and adjacent level, adjacent segment degeneration (ASD), and heterotopic ossification (HO). RESULTS At the final follow-up, there were no significant differences in JOA, VAS neck, and VAS arm scores between the two groups. However, NDI scores improved more in the CDA group than in the ACDF group. The sagittal alignment was maintained in both groups. The ROM at the index level in the CDA group was decreased from 9.6±4.3° at baseline to 7.8±4.7° at the final follow-up. The ROM at the cranial adjacent level in the ACDF group was increased. The incidence of ASD was lower in the CDA group than in the ACDF group (26.7% vs 49.1%, p=0.023). HO was observed in 46.7% of the patients but did not influence the clinical outcome. CONCLUSION Both CDA with Prestige-LP Disc and ACDF showed good clinical outcomes at a minimum 6-year follow-up. Compared with ACDF, CDA preserved the motion and reduced the incidence of ASD.

The biomechanical impact of facet tropism on the intervertebral disc and facet joints in the cervical spine

BACKGROUND CONTEXT Facet tropism is defined as the angular difference between the left and the right facet orientation. Facet tropism was suggested to be associated with the disc degeneration and facet degeneration in the lumbar spine. However, little is known about the relationship between facet tropism and pathologic changes in the cervical spine and the mechanism behind. PURPOSE This study was conducted to investigate the biomechanical impact of facet tropism on the intervertebral disc and facet joints. STUDY DESIGN A finite element analysis study. METHODS The computed tomography (CT) scans of a 28-year-old male volunteer was used to construct the finite element model. First, a symmetrical cervical model from C2 to C7 was constructed. The facet orientations at each level were simulated using the data from our previously published study. Second, the facet orientations at the C5-C6 level were altered to simulate facet tropism with respect to the sagittal plane. The angular difference of the moderate facet tropism model was set to be 7 degrees, whereas the severe facet tropism model was set to be 14 degrees. The inferior of the C7 vertebra was fixed. A 75 N follower loading was applied to simulate the weight of the head. A 1.0 N⋅m moments was applied on the odontoid process of the C2 to simulate flexion, extension, lateral bending, and axial rotation. RESULTS The intradiscal pressure (IDP) at the C5-C6 level of the severe facet tropism model increased by 49.02%, 57.14%, 39.06%, and 30.67%, under flexion, extension, lateral bending, and axial rotation moments, in comparison with the symmetrical model. The contact force of the severe facet tropism model increased by 35.64%, 31.74%, 79.26%, and 59.47% from the symmetrical model under flexion, extension, lateral bending, and axial rotation, respectively. CONCLUSIONS Facet tropism with respect to the sagittal plane at the C5-C6 level increased the IDP and facet contact force under flexion, extension, lateral bending, and axial rotation. The results suggested that facet tropism might be the anatomic risk factor of the development of cervical disc degeneration or facet degeneration. Future clinical studies are in need to verify the biomechanical impact of facet tropism on the development of degenerative changes in the cervical spine.

Anterior release and nonstructural bone grafting and posterior fixation for old lower cervical dislocations with locked facets

Abstract Lower cervical dislocations are often missed at the time of initial injury for several reasons. The treatment of old facet dislocations of the lower cervical spine is difficult, and the optimal method has not been established. The objective of the present study was to evaluate the clinical outcomes of a surgical technique, anterior release, and nonstructural bone grafting combined with posterior fixation, for the treatment of old lower cervical dislocations with locked facets. This was a retrospective study of 17 patients (13 men and 4 women) with old facet dislocations, who underwent the same surgical treatment at our hospital between April 2010 and January 2016. The anterior procedure was conducted to remove the fusion mass and to achieve discectomy and morselized bone grafting. Subsequent posterior procedure included release, reduction, and posterior fusion. The neurologic status, clinical data (Japanese Orthopedic Association [JOA], Neck Disability Index [NDI], and Visual Analog Scale [VAS] scores), and radiographic information (local sagittal alignment and bone graft fusion) were recorded and evaluated pre and postoperatively. All patients achieved a nearly complete reduction intraoperatively. The mean operative time was 178 ± 49 minutes. The mean blood loss was 174 ± 73 mL. Each patient completed at least 12 months of follow-up. The mean follow-up duration was 32.6 ± 18.5 months. The neurologic status according to the Frankel grade was significantly improved at the last follow-up. The JOA, NDI, and VAS scores all demonstrated significant improvements compared with the preoperative values (P < .05). The kyphosis angle of the dislocated segments was 10.5 ± 5.9° at preoperation, and was corrected to 5.9 ± 4.3° lordosis postoperatively. Anterior and posterior solid fusion was observed in all patients within 12 months of follow-up. Fat liquefaction and delayed healing of the posterior wound occurred in 1 patient. Cerebrospinal fluid leakage occurred in another patient. There was no neurologic deterioration and no procedure-related complications. Anterior release and nonstructural bone grafting combined with posterior fixation provides a safe and effective option for treating old lower cervical dislocations with locked facets.

Three-dimensional Printed Patient-specific Drilling Templates for Expansive Open-door Laminoplasty

The expansive open‐door laminoplasty (EOLP) has been proven effective in treating patients with cervical myelopathy caused by bony cervical stenosis or ossification of the posterior longitudinal ligament.[1] The aim of the EOLP was to help patients gain neurological improvement by decompressing the spinal cord and nerve root. The trough preparation was a critical procedure for successful EOLP, for which the appropriate trough position and drilling depth mattered the most. For now, the trough preparation was solely based on the surgeon’s experience. Although the surgery‐related complications were uncommon, the consequences were severe.[2] Rich experience was required to reduce the incidence of surgery‐related complications. However, under some circumstances where the junction between the lamina and the lateral mass was obscure, it was even challenging for an experienced surgeon to accomplish the proper trough preparation. Here, we presented a case of EOLP using the three‐dimensional printed patient‐specific drilling. Using the computer‐aided design (CAD) and rapid prototyping (RP) techniques, the positions of troughs and drilling depths were simulated preoperatively, and the drilling templates were fabricated to guide the trough preparation intraoperatively.