Objective To explore changes in the height and width of the cervical intervertebral foramina of C6,7 before and after the C5,6 discetomy, the replacement or the anterior intervertebral fusion so as to provide the theoretical basis for the clinical practice. Methods Eleven fresh cervical spinal specimenswere obtained from young adult cadavers. The specimens of C5,6 were divided into the integrity group, the discectomy group, the artificial disc replacement group, and the intervertebral fusion group. The range of variety (ROV) of the C6,7 intervertebral foramen dimensions (height, width) before and after the loading tests (0.75, 1.50 Nm) were measured in the 4 groups. Results The C6,7 intervetebral foramen height and width increased significantly during flexion (Plt;0.01) but decreased significantly during extension (Plt;0.01). There was a significantdifference between the two test conditions in each of the 4 groups (Plt;0.01). However, in the two test conditions there was no significant difference in ROV of the C6,7 intervetebral foramen height and width during flexion and extension betweenthe integrity group, the discectomy, and the artificial disc replacement group（Pgt;0.05）, but a significant difference in the above changes existed in the intervertebral fusion group when compared with the other 3 groups (Plt;0.05). In the same group and under the same conditions, the ROV of the C6,7 intervetebral foramen height and width was significantly different in the two test conditions (Plt;0.01). Conclusion The results have indicated thatartificial disc replacement can meet the requirements of the normal cervical vitodynamics. The adjacent inferior cervical intervetebral foramen increases during flexion but decreases during extension. The intervertebral fusion is probably one of the causes for the cervical degeneration or the accelerated degeneration and for the cervical spondylotic radiculopathy and the brachial plexus compression.
ObjectiveTo observe the in vivo three-dimensional (3-D) transient motion characteristics of the subaxial cervical spine in healthy adults.
MethodsSeventeen healthy volunteers without cervical spine related diseases were recruited for this study, including 8 males and 9 females with a mean age of 26 years (range, 23-41 years). The vertebral segment motion of each subject was reconstructed with CT, and Rhinoceros 4.0 solid modeling software were used for 3-D reconstruction model of the subaxial cervical spine. In vivo cervical vertebral motion in flexionextension, left and right bending, left and right rotation was observed with dual fluoroscopic imaging system (DFIS). Coordinate systems were established at the vertebral center of C3-7 to obtain the intervertebral range of motion (ROM) and displacement at C3, 4, C4, 5, C5, 6, and C6, 7. The X-axis pointed to the left along the coronal plane, the Y-axis pointed to the back along the sagittal plane, and the Z-axis perpendicular to the X-Y plane pointed to the head. The ROM along X, Y, and Z axises were represented by rotation in flexion-extension (α), in left-right bending (β), and in left-right twisting (γ) respectively, and the displacement in left-right direction (x), in anterior-posterior direction (y), and in proximaldistal direction (z), respectively.
ResultsIn flexion and extension, the displacement in anterior-posterior direction of C6, 7 was significantly less that of other segments (P<0.05), but the displacements in left-right direction and in proximaldistal direction showed no significant difference between segments (P>0.05); the ROM values in flexion-extension of C4, 5 and C5, 6 were significantly larger than those of C3, 4 and C6, 7 (P<0.05), and the ROM value in left-right twisting of C4, 5 was significantly larger than those of C5, 6 and C6, 7 (P<0.05), but the ROM value in left-right bending showed no significant difference between segments (P>0.05). In left and right bending, there was no significant difference in the displacement between other segments (P>0.05) except that the displacement in anterior-posterior direction of C3, 4 was significantly larger than that of C4, 5 (P<0.05), and that the displacement in proximal-distal direction of C6, 7 was significantly less than that of C3, 4 and C4, 5 (P<0.05); no significant difference was shown in the ROM value between segments (P>0.05), except that the ROM value in left-right twisting of C3, 4 was significantly larger than that of C5, 6 and C6, 7 (P<0.05). In left and right rotation, the ROM value in left-right twisting of C3, 4 was significantly larger than that of C4, 5 and C6, 7 (P<0.05), and the displacement and ROM value showed no significant differece between other segments (P>0.05).
ConclusionThe intervertebral motions of the cervical spine show different characters at different levels. And the 6-degree-of-freedom data of the cervical vertebrae are obtained, these data may provide new information for the in vivo kinematics of the cervical spine.
Objective To explore the feasibilities, methods, outcomes and indications of atlas pedicle screw system fixation and fusion for the treatment of upper cervical diseases. Methods From October 2004 to January 2006, 17 patients with upper cervical diseases were treated with atlas pedicle screw system fixation and fusion. There were 13 males and 4 females, ageing 19 to 52 years. Of 17 cases, there were 14 cases of atlantoaxial dislocation(including 3 cases of congenital odontoid disconnection，4 cases of old odontoid fracture，2 cases of new odontoid fracture(typeⅡC), 3 cases of rupture of the transverse ligament, and 2 cases of atlas fracture； 2 cases of tumor of C2; 1case of giant neurilemoma of C2,3 with instability after the resection oftumors. JOA score before operation was 8.3±3.0. Results The mean operative time and bleeding amount were 2.7 hours (2.1-3.4 hours) and 490 ml (300-750 ml) respectively. No injuries to the vertebral artery and spinal cord were observed. The medial-superior cortex of lateral mass was penetrated by 1 C1 screw approximately 3 mmwithout affecting occipito-atlantal motions. All patients were followed up 3-18 months. The clinical symptoms were improved in some extents and the screws were verified to be in a proper position, no breakage or loosening of screw and rob occurred. All patients achieved a solid bone fusion after 3-6 months. JOA score 3 months after operation was14.6±2.2. JOA improvement rates were 73%-91%(mean 82%). Conclusion The atlas pedicle screw system fixation and fusion is feasible for the treatment of upper cervical diseases and has betteroutcomes, wider indications if conducted properly.
Objective To evaluate the fixation technique of using the cervical lateral mass plate in the cervical posterior approach operation. Methods Eight patients in this group were admitted from September 2001 to November 2006. Among the 8 patients, there were 6 males and 2 females, with their ages ranging from 28 to 78 years. Cervical vertebral fracture with dislocation was found in 4 patients, C2 spinal cord injury in 1, C1 fracture in 1, cervical spinal stenosis in 1, and C2-5 spinal cord neurofibroma in 1. Muscle strength 3-4. TheFrankel grading system was usedin 6 patients with traumatic injury. Before operation, Grade C was observed in 2patients，Grade D in 3，and Grade E in 1. All the operations were performed according to requirements of the Margel’s method. We positioned 40 screws in all the patients, including 4 screws at C2，6 screws at C3，12 screws at C4，4 screws at C5，4 screws at C6，2 screws at C7，and 6 screws at T1. Results The followingup for an average of 14.1 months (range,645 months) revealed that there was no malposition of the screws in the patients. One of the 8 patients developed spinal instability in the fixed segment at 3 months after operation. The headchestbrace was applied to the patient for 3 months, and the spinal fusion was achieved. The further followingup to 45 months indicated that there was no instability occurring. The remaining patients recovered to their spinal stability by the spinal fusion. The patients also recovered in their neurological function after operation. The Frankel assessment showed that 1 patient had Grade E, 3 from Grade D to Grade E, 1 from Grade C to Grade D, and 1 from Grade C to Grade E. Conclusion The cervical lateral mass plate fixation can provide the immediate and b segmental immobilization for the good cervical spine stability.
Objective To study the prevention and management of early compl ications associated with anterior cervical spinal surgery. Methods From November 1998 to December 2006, 363 cases were treated with anterior cervicalsurgery, including 268 males and 95 females aged 17-79 years．In these cases, 224 suffered from cervical spondylosis, 39 from cervical disc herniation, 87 from cervical trauma, 9 from cervical tumor and 4 from cervical tuberculosis. Forty-eight cases with anterior cervical surgery were fused by autogenous il iac bones, 132 cases with anterior cervical surgery were fused by autogenous il iac bones and anterior cervical spine locking plates, and 183 cases with anterior cervical surgery were fused by titanium mesh cage and anterior cervical spine locking plates. Results A total of 282 cases were followed up for 3 months to 5 years with the average of 1 year and 11 months. Twenty-three compl ications associated with surgery were found, with an incidence of 8.16%. Three cases of transient superior laryngeal nerve palsy recovered within 3-7 days after the restriction of l iquid diet and fluid replacement. Two cases of recurrent laryngeal nerve palsy recovered by 3-month pronunciation practice. One case of spinal cord injury was treated with medicine for dehydration and anti-inflammation, and was restored to preoperative muscle power of inferior extremity after 6 months. Two cases of CSF leakage were cured with moderate local compression and meticulous water-tight wound closure. Among the 10 patients with compl ications of internal fixation, one suffering mild dysphagia was reoperated, while the others were treated with cephal-cervico-thorax plaster external fixation and recovered with sol id fusion within 3-18 months. Among the 4 cases with cervical hematoma, 1 died of wrong rescue procedures and 1 was infected. Conclusion Adequate preoperative preparation, thorough understanding of anatomy related to the anterior approach and skilled surgical technique are essential for preventing the early postoperative compl ications of anterior cervical spinal surgery．
Objective To investigate and compare the effects of restoring and maintaining the cervical curvature and height of the fused segment by using three different anterior cervical plate systems. Methods From January 2002 to June 2004, 122 patients underwent anterior cervical decompression,autogenous iliac bone graft and plate fixation. Of the 122 patients (85 males, 37 females, aged 14-70), 37 underwent surgery involving the fixation with the Orion plate system, 39 with the Zephir plate system, and 46 with the Codman platesystem. The cervical curvature and height of the fused segment were measured onthe lateral X-ray films so as to compare the changes of the conditions preoperatively,1 week after surgery, and during the follow-up, and also to compare the difference among the three groups. Results The follow-up of the patients for 6-35 months (average 17.3 months) showed that all the patients developed the bone fusion 6 months after operation. There was a significant improvement in the cervical curvature and height of the fused segment before operation versus 1 week after operation（Plt;0.05）; however, there were no significant changes 1 week after operation versus during the followup in each group（Pgt;0.05）; there was no significant difference among the three groups（Pgt;0.05）. Conclusion The three plate systems can effectively reconstruct and maintain the cervical curvature and height of the fused segment, with a satisfactory effect in a short term.
Objective To develop a high-accuracy, better-safety and low-cost cervical pedicle locator system for guiding cervical pedicle screw placement. Methods Cervical pedicle screw locator system was made of stainless steel. Ten cervical specimens from voluntary donation were divided into two groups according to compatibil ity design: control group inwhich 60 screws were planted into C2-7 by free hand; and experimental group in which 60 screws were planted into C2-7 under the guidance of three-dimensional locator system. The condition of screw insertion was observed and the accuracy was evaluated by the integrity of pedicle walls. Results In the control group, 32 screws (53.33%) were placed inside the pedicles and 28 (46.67%) were outside; 9 screws (15.00%) led to nerve root injury, 5 screws (8.33%) caused vertebral artery injury and no spinal cord injury occurred; and the qual ification ratio of screw insertion was 76.67% (excellent 32, fair 14, poor 14). While in the experimental group, 54 screws (90.00%) were placed inside the pedicles and 6 (10.00%) were outside; 1 screw (1.67%) caused vertebral artery injury and no nerve root injury and spinal cord injury occurred; and the qual ification ratio of screw insertion was 98.33% (excellent 54, fair 5, poor 1). There was significant difference between the two groups (P lt; 0.05). Conclusion Cervical pedicle screw locator system has the advantages of easy manipulation, high accuracy of screw placement and low cost. With further study, it can be appl ied to the cl inical.
ObjectiveTo design the method of posterior percutaneous full-endoscopic cervical foraminotomy (P-PECF) for treating cervical osseous foraminal stenosis and analyze its feasibility in clinical application.MethodsThe clinical data of 12 patients with cervical osseous foraminal stenosis who met the selection criteria between October 2015 and June 2017 were retrospectively analysed. There were 7 males and 5 females with an age of 52-63 years (mean, 57.6 years). The disease duration ranged from 15 days to 6 months (mean, 3.7 months). The segments included C4, 5 in 2 cases, C5, 6 in 6 cases, and C6, 7 in 4 cases; all showing root pain or numbness caused by nerve root compression. All patients were treated with the P-PECF technique. At preoperation, immediately after operation, and at last follow-up, visual analogue scale (VAS) scores and neck disability index (NDI) were respectively recorded to assess the patient’s quality of life and the pain of neck and arm. The clinical outcomes were evaluated by the modified Macnab criteria.ResultsAll operations were successful. The operation time was 71-105 minutes (mean, 82 minutes); the intraoperative blood loss was about 5 mL. The CT of the cervical spine at 1 week postoperatively showed that the cervical root canal was enlarged and the nerve root compression was relieved. The symptoms of neck and arm pain and numbness were relieved; the hospitalization time was 2-5 days (mean, 3 days). All patients were followed up 6-18 months (mean, 12.3 months). Except for 1 patient’s feeling transient hypoesthesia postoperatively, there was no complication such as hematoma, nerve root injury, or incision infection. The VAS scores and NDI at immediate postoperatively and at last follow-up were significantly improved when compared with preoperative scores (P<0.05); and the scores also improved significantly at last follow-up when compared with the scores at immediate postoperatively (P<0.05). According to modified Macnab criteria, the results were excellent in 9 cases, good in 2 cases, and fair in 1 case, with an excellent and good rate of 91.7%.ConclusionThe P-PECF technique can enlarge the nerve root canal and relieve nerve root compression, and obtain better effectiveness by minimally invasive methods. It is a safe and feasible procedure.
Objective To summarize the methods andskills of anterior cervical locking plate systems in clinical application and to analyze the causes of some complications as well as give some preventive or remedial countermeasures. Methods From 1998 to 2002, 159 patients with cervical spondylotic myelopathy,fracturedislocation,tumor or tuberculosis of the cervical spine were treated with anterior locking plate systems. The complications were reviewed and analyzed. Results Ten kinds of complications related to anterior locking plate systems occurred in 21 patients. Most of the complications were caused by improperly-selecting implants, experience and technique deficiency. Conclusio The important preventive or remedial countermeasures are correctly-selecting patients, meticulous preoperative preparation, properly-selecting implants, standard and skillful manipulation and rational postoperative protection.
ObjectiveTo assess the causal relationship between cervical vertebra related disorders and essential hypertension using a bidirectional two-sample Mendelian randomization study approach. MethodsThe research data comes from the genome-wide association study dataset. Four types of cervical vertebra related disorders: cervicalgia, cervical disc disorders, cervical root disorders, injury of nerves and spinal cord at neck level, as well as data on essential hypertension, were selected for the study. Relevant single nucleotide polymorphisms were selected as instrumental variables to assess the causal relationship between cervical vertebra related disorders and essential hypertension mainly by inverse variance weighted model ratio. Cochran's Q test was used to detect heterogeneity, MR-Egger intercept term and MR-PRESSO was used to detect multiplicity, and leave-one-out method was used for sensitivity analysis. ResultsCervicalgia had a positive causal relationship with the essential hypertension (OR=1.01, 95%CI 1.00 to1.02, P=0.019). Essential hypertension had a positive causal relationship with the cervical disc disorders (OR=4.08, 95%CI 1.57 to10.61, P=0.004). There was no significant causal relationship between cervical root disorders, injury of nerves and spinal cord at neck level and essential hypertension. Reliability assessment indicates that the study results were reliable. ConclusionCervicalgia is a risk factor for essential hypertension; Essential hypertension is a risk factor for cervical disc lesions; There is no correlation between cervical root disorders, injury of nerves and spinal cord at neck level and essential hypertension.
