Cervical Curvature Index Research Articles

Predictors for Surgical Outcome of Laminoplasty for Cervical Spondylotic Myelopathy

There were no precise researches showing which parameters with regard to degree of cervical stenosis and sagittal cervical alignment are the most crucial for surgical outcomes after laminoplasty for cervical spondylotic myelopathy (CSM). The objectives of this study were to investigate to what extent the preoperative parameters may have a direct influence on postoperative neurologic recovery, and to determine the crucial determinants of prognosis. A retrospective review of 83 patients with CSM after laminoplasty was conducted. Magnetic resonance imaging parameters evaluation included presence/absence of signal change on T1 and T2 and anatomic measurements, including cervical canal compromise and cervical alignment. Data analysis involved logistic regressions and Spearman rank correlation coefficients. Receiver operator characteristic (ROC) curves were computed to evaluate the contribution of the original model. Univariate logistic regression showed that age (odds ratio= 0.822; 95% confidence interval, 0.729-0.927; P= 0.001), baseline Japanese Orthopedic Association (JOA) score (odds ratio= 1.700; 95% confidence interval, 1.158-2.496; P= 0.007), cervical curvature index (Ishihara) score (CCI) (odds ratio= 1.123; 95% confidence interval, 1.030-1.225; P= 0.008), maximum canal compromise (MCC) (odds ratio= 0.940; 95% confidence interval, 0.885-0.998; P= 0.041), and signal intensity (odds ratio= 0.139; 95% confidence interval, 0.033-0.580; P= 0.007) were independent prognostic indicators after laminoplasty. A ROC curve was computed based on the probability of the five predictors, with an area under the curve of 0.929 ± 0.028. Age and baseline JOA scores were crucial clinical predictors of outcome after laminoplasty for patients with CSM. Regarding the predictive value, CCI, MCC, and patterns of signal intensity changes on T1-/T2-weighted images were crucial determinants of prognosis of neurologic outcome.

Laminoplasty versus laminectomy and fusion for multilevel cervical compressive myelopathy: A meta-analysis.

This is a meta-analysis to compare the results between laminoplasty and laminectomy followed by fusion for the patients with multilevel cervical compressive myelopathy. An extensive search of literature was performed in MEDLINE, Embase, the Cochrane library, CNKI, and WANFANG. The following outcome measures were extracted: the Japanese Orthopaedic Association (JOA) scores, cervical curvature index (CCI), visual analog scale (VAS), cervical lordosis (C2–7), complications, blood loss, and operation time. Data analysis was conducted with RevMan 5.3 and STATA 12.0. A total of 23 studies comprising 774 and 743 patients treated with laminoplasty and laminectomy followed by fusion, respectively, were included in the final analysis. The pooled analysis showed that there was no significant difference in preoperative JOA scores [P = 0.89], postoperative JOA scores [P = 0.13], JOA scores improvement rate [P = 0.27], preoperative CCI [P = 0.15], postoperative CCI [P = 0.14], preoperative VAS [P = 0.41], postoperative VAS [P = 0.52], preoperative cervical lordosis (C2–7) [P = 0.46], postoperative cervical lordosis (C2–7) [P = 0.67], total complications [P = 0.07], axial pain [P = 0.94], and blood loss [P = 0.51]. However, there were significant difference in operation time (WMD = −19.57 [−32.11, −7.02], P = 0.002) and C5 palsy (OR = 0.26 [0.15, 0.44], P < 0.001). As compared with laminectomy followed by fusion, expansive laminoplasty showed no significant differences in JOA scores, CCI, ROM, VAS, cervical lordosis (C2–7), axial pain, total complications, and blood loss, but shorter operation time and fewer C5 palsy.

The role of iatrogenic foraminal stenosis from lordotic correction in the development of C5 palsy after posterior laminectomy and fusion.

BackgroundPost-operative C5 nerve root palsy is a known complication following cervical spine surgery. Although several theories have been proposed, there remains no consensus as to the etiology of the palsies. Multiple pre-operative radiographic measures have been assessed for utility in predicting palsy. The purpose of this study is to evaluate published radiographic parameters as well as specifically evaluate the effect of cervical lordosis in the development of C5 palsy to establish thresholds that reliably predict the incidence.MethodsThis study is a retrospective review of 54 consecutive multilevel cervical laminectomy and fusion surgeries performed by a single spine surgeon between June 2007 and February 2014. Pre-operative MRI and pre- and post-operative plain films were assessed to measure anteroposterior diameter (APD) of the spinal cord, cervical laminar angles, anteroposterior foraminal diameters (FD), cervical curvature index (Ishihara), cervical spine angle (C2-7), and C4-5 angle. Univariate analysis through independent t tests was used to compare differences between groups. Stepwise logistic regression was performed to identify pre-operative variables associated with C5 palsy. Receiver operating characteristic curves were created for significant variables to assess predictive accuracy through determining the area under the curve.ResultsThere were 13 (24 %) palsies in the 54 patients in the study. All palsies completely resolved within 6 months. Among pre-operative measures, FD and APD were significantly different between the palsy and non-palsy groups. The average post-operative C4-5 angle was significantly different between the groups, though the cervical spine angle and curvature index, as well as the change in these measures from pre-operative measurements, did not differ significantly between groups.ConclusionsPost-operative palsy is likely a result of iatrogenic nerve root compression from a decreased in cross-sectional area of the neuroforamen in a patient with pre-operative narrowing of the foramen. However, spinal cord drift back may also play a role from the combined effect of posterior decompression from laminectomy and relative slack afforded by increased lordosis. Accordingly, increased post-operative lordosis would increase the likelihood of effect from both of these mechanisms. We recommended limited conservative lordotic correction in patients with pre-operative foraminal narrowing.

Therapeutic effect and mechanism of the surgical treatment for cervical vertigo with cervical spondylosis

To investigate the therapeutic effect and mechanism of the surgical treatment for cervical vertigo with cervical spondylosis. Thirty-five patients in Department of Orthopaedics, Peking Union Medical College Hospital, Peking Union Medical College, who received surgical treatment for cervical spondylosis concomitant with cervical vertigo from 2004 to 2013 were reviewed retrospectively. The preoperative cervical curvature index (CCI), slip distance and intervertebral angle, as well as the pre-and-postoperative Cobb angle were measured. The pre-and-postoperative degree of vertigo was reported according to the American Academy of Otolaryngology-Head and Neck Surgery Committee on Hearing and Equilibrium standard. The therapeutic effect and mechanism for patients with different imaging features and thus underwent various surgical approaches were analyzed. The mean follow-up was 40.6 months. Cervical instability was found in 33 patients. 29 of 35 (82.9%) patients had a satisfied recovery from cervical vertigo. The difference in Cobb angle in pre- and postoperative neutral cervical X-ray images was positively associated with the improvement for the vertigo (Pearson's test, P < 0.05). Cervical instability may be the major cause of cervical vertigo in the context of cervical spondylosis. Cervical sympathetic nerves may have played an important role in the cervical vertigo. Surgery may relieve the cervical vertigo accompanying the cervical spondylosis.

Expansive Open-Door Cervical Laminoplasty: In Situ Reconstruction of Extensor Muscle Insertion on the C2 Spinous Process Combined With Titanium Miniplates Internal Fixation.

Retrospective cohort study.To evaluate efficacy and relevant problems of in situ reconstruction of extensor muscle insertion on the C2 spinous process combined with titanium miniplates internal fixation in expansive open-door cervical laminoplasty in order to improve surgical treatment effect.Expansive open-door cervical laminoplasty has been widely applied in clinical practice, but there are a series of postoperative problems. Therefore, decreasing postoperative complications in order to more effectively relieve symptoms remains a subject for additional research.From October 2011 to September 2013, a total of 60 patients who suffered cervical canal stenosis were treated by expansive open-door laminoplasty with in situ reconstruction of extensor muscle insertion on the C2 spinous process combined with titanium miniplates internal fixation. Changes of cervical curvature index (CI) and range of motion (ROM) were calculated using data from preoperative and postoperative cervical spine X-ray examinations. Clinical function was scored using the Japanese Orthopedics Association Scoring System (JOA) and the neck disability index (NDI).The mean CI before the operation and at 1-year postoperation were 10.49% ± 3.93% and 14.14 ± 2.85 (P < 0.05). The mean ROM values were 43.35 ± 7.55 before the operation, 34.83 ± 7.41 at 1-year postoperation (P < 0.05). The NDI scores decreased from 19.42 ± 4.12 to 7.37 ± 2.58, and the JOA scores increased from 8.87 ± 1.99 to 13.55 ± 1.72, representing significant improvement (P < 0.05). One patient had postoperative C5 nerve root palsy and completely recovered 1 month later. Neither collapse nor door closure in the open-door side occurred in any of the patients.Expansive open-door cervical laminoplasty with in situ reconstruction of extensor muscle insertion on the C2 spinous process combined with titanium miniplates internal fixation is a safe and effective surgical method, and can effectively decrease postoperative complications and achieve satisfactory clinical results.

Effect of partial foraminotomy after laminoplasty surgery on preventing C5 nerve root palsy

Objective To investigate clinical curative effect of partial foraminotomy after C4,5 ossification of posterior longitudinal ligament (OPLL) on preventing C5 nerve root palsy. Methods A total of 155 patients with OPLL were treated with expansion open-door laminoplasty (EOLP) between January 2008 and October 2012, including 75 male patients and 80 female patients, with average age of 54.5 (ranging from 38 to 75). Among them, 90 cases took EOLP (open team), and 65 cases took EOLP and C4,5 partial foraminotomy (incision team). Clinical curative effect and imaging evaluation were used in 8 weeks and 12 months after operation. JOA scores, JOA scores improvement rate, C5 nerve root palsy occurrence rate, neurological function of patients with C5 nerve root palsy and the prognosis, cervical curvature index, opening angular variation, backward drift distance of anterior margin and posterior margin of the spinal cord were evaluated after 8 weeks and 1 year after the surgery. Results The operation time was 90-140 min, with the average time of 110±14 min; mean bleeding volume was 160±45 ml (ranging from 100 to 250 ml); follow-up visit time was 15.4 months on average (ranging from 12 to 18 months). JOA score and improvement rate after 8 weeks and 1 year of the operation have no statistical significance. The C5 nerve root palsy occurrence rate in open team was 8.89% (8/90), while that in incision team was 4.62% (3/65). The difference of two groups has statistical significance. C5 nerve root palsy all happened in laminar opening side. Comparison of cervical curvature index of two groups before the operation and after 8 weeks of the operation and inter-group comparison have no statistical significance. The difference between laminar opening angle after 1 year of the operation and laminar opening angle after 8 weeks has no statistical significance. The difference of backward drift distance of anterior margin of the spinal cord at different time after the operation and inter-group difference have no statistical significance. The difference in backward drift distance of posterior margin of the spinal cord between 1 year after the operation and 8 weeks after the operation has no statistical significance. Conclusion Treating OPLL with EOLP and C4,5 partial foraminotomy can reduce occurrence rate of C5 nerve root palsy, but has no significant influence on JOA score improvement rate. Key words: Cervical vertebrae; Foraminotomy; Decompression, surgical; Comparative study

Effect of Lamina Open Angles in Expansion Open-door Laminoplasty on the Clinical Results in Treating Cervical Spondylotic Myelopathy

A retrospective study. To evaluate and compare the relation of the efficacy and clinical results of expansion open-door laminoplasty (EOLP) with different angles in lamina open-door. EOLP is currently the most widely adopted surgical treatment for cervical spondylotic myelopathy. Although many long-term clinical follow-up studies have reported that most patients recover satisfactorily after EOLP, there have been numerous reports regarding postoperative complications, such as stubborn axial symptoms (AS) and C5 palsy. The lamina open-door angles in EOLP play a decisive role in determining the openness of the door that affects clinical outcomes. Nonetheless, no thorough studies on different angles in EOLP have been published. A total of 198 cervical spondylotic myelopathy patients who underwent posterior cervical EOLP and at least 24 months follow-up treatment between July 2006 and January 2009 were selected as case studies. Among the 198 cases used, there were 39 double-segment cases with the location being C3-C5 in 11 cases and C4-C6 in 28 cases, 97 three-segments (C4-C7) and 62 four segments (C3-C7). All of the patients underwent x-ray, computed tomography, and magnetic resonance imaging images for evaluation of the cervical spine. According to different opening angles, measured by computed tomography scan after operation 1 week, the patients were divided into 2 groups, group A (>30 degrees, 76 patients including 44 males and 32 females) and group B (15-30 degrees, 122 patients including 71 males and 51 females). All patients were followed up for over 24 months, clinical results including operative duration, intraoperative bleeding volume, postoperative complications, C2-C7 Cobb angle, cervical curvature index (CI), range of motion (ROM), and values after the spinal cord backward shift were analyzed statistically, evaluating the neurological function at final follow-up and calculating the improvement rate of nerve function recovery. There was no statistically significant difference (P>0.05) between the 2 groups in the following areas: the Japanese Orthopedic Association scores, C2-C7 Cobb angle, cervical CI, and ROM. In addition, operative duration and intraoperative bleeding volume between A group and B group showed no significant differences (P>0.05). After surgery, 51 patients (67.1%) in group A had AS, 8 patients (10.4%) had C5 palsy, and 1 patient had mild cervical kyphosis. Whereas postoperatively group B contained 37 cases (10.5%) with AS, 3 (2.4%) with C5 palsy, and in 4 cases (3.28%) the lamina open-door had reclosed. The rate of patients with AS and C5 palsy in group A was higher than group B. The incidence of postoperative complications between the 2 groups have a significant difference (P<0.05). The rate of improvement of Japanese Orthopedic Association scores in last follow-up between group A and group B did not reach statistical significance (P>0.05). At the 1-month follow-up the range of the value of spinal cord backward shift was 0-7.95 mm with the average being 2.41±0.46 mm. C2-C7 Cobb angle, CI, and ROM between the 2 groups revealed no statistical significance (P>0.05). ROM comparisons preoperatively and postoperatively between the 2 groups were significantly different (P<0.05). In different angles of lamina open-door, the improvement rate of neurological function after surgery had no statistically significant difference between 2 groups. When the open-door angle is maintained between 15 and 30 degrees, it can reduce the incidence of C5 palsy in the hinge side and AS, but we should prevent reclosure of the lamina open-door.

Laminoplasty versus laminectomy and fusion for multilevel cervical myelopathy: a meta-analysis of clinical and radiological outcomes.

OBJECT Posterior cervical surgery, expansive laminoplasty (EL) or laminectomy followed by fusion (LF), is usually performed in patients with multilevel (≥ 3) cervical spondylotic myelopathy (CSM). However, the superiority of either of these techniques is still open to debate. The aim of this study was to compare clinical outcomes and postoperative kyphosis in patients undergoing EL versus LF by performing a meta-analysis. METHODS Included in the meta-analysis were all studies of EL versus LF in adults with multilevel CSM in MEDLINE (PubMed), EMBASE, and the Cochrane library. A random-effects model was applied to pool data using the mean difference (MD) for continuous outcomes, such as the Japanese Orthopaedic Association (JOA) grade, the cervical curvature index (CCI), and the visual analog scale (VAS) score for neck pain. RESULTS Seven studies comprising 302 and 290 patients treated with EL and LF, respectively, were included in the final analyses. Both treatment groups showed slight cervical lordosis and moderate neck pain in the baseline state. Both groups were similarly improved in JOA grade (MD 0.09, 95% CI -0.37 to 0.54, p = 0.07) and neck pain VAS score (MD -0.33, 95% CI -1.50 to 0.84, p = 0.58). Both groups evenly lost cervical lordosis. In the LF group lordosis seemed to be preserved in long-term follow-up studies, although the difference between the 2 treatment groups was not statistically significant. CONCLUSIONS Both EL and LF lead to clinical improvement and loss of lordosis evenly. There is no evidence to support EL over LF in the treatment of multilevel CSM. Any superiority between EL and LF remains in question, although the LF group shows favorable long-term results.

Risk factors associated with upper extremity palsy after expansive open-door laminoplasty for cervical myelopathy

Background contextPostoperative paresis, so-called C5 palsy, of the upper extremities is a common complication of cervical surgery. There have been several reports about upper extremity palsy after cervical laminoplasty for patients with cervical myelopathy. However, the possible risk factors remain unclear. PurposeTo investigate the factors associated with the development of upper extremity palsy after expansive open-door laminoplasty for cervical myelopathy. Study designA retrospective review of medical records. Patient sampleA total of 102 patients (76 men and 26 women) were eligible for analysis in this study. The mean age of the patients was 58.7 years (range 35–81 years). Sixteen patients (13 men and 3 women, average age 62.8 years) with palsy were categorized as Group P, and eighty-six patients (63 men and 23 women, average age 57.8 years) without palsy as Group C. Outcome measuresThe demographic data collected from both groups were age, sex, duration of symptoms, disease, and type of surgical procedure. Cervical curvature index, width of the intervertebral foramen (WIF) at C5, anterior protrusion of the superior articular process (APSAP), number of compressed segments, high–signal intensity zone at the level corresponding to C3–C5 (HIZ:C3–C5), and posterior shift of the spinal cord (PSSC) were also evaluated. MethodsUpper extremity palsy was defined as weakness of Grade 4 or less of the key muscles in the upper extremity by manual muscle test without any deterioration of myelopathic symptoms after surgery. Comparisons were made with screen for the parameters with significant differences, and then we further analyzed these parameters by logistic regression analysis (the forward method) to verify the risk factors of the upper extremity palsy. ResultsSignificant differences in diagnosis, the type of procedure, WIF, APSAP, and HIZ:C3–C5 were observed between the two groups. No statistical difference in PSSC between the groups was noted (2.06 vs. 2.53 mm, p=.247). In logistic regression analysis, ossification of the posterior longitudinal ligament (OPLL), cervical open-door laminoplasty together with posterior instrumented fusion (CLP+PIF), and WIF were found to be significant risk factors for postoperative upper extremity palsy. ConclusionsPatients with preoperative foraminal stenosis, OPLL, and additional iatrogenic foraminal stenosis because of CLP+PIF were more likely to develop postoperative upper extremity palsy. Attention should be given to the WIF determined on preoperative computed tomography of the C5 root. To prevent iatrogenic foraminal stenosis, appropriate distraction between spine segments should be provided during placement of the rod.

Anterior migration of spinal cord after anterior cervical decompression and reconstruction for cervical spondylosis

Objective To investigate anterior migration of spinal cord after anterior cervical decompression and reconstruction for cervical spondylosis and its mechanism.Methods Eighty-one patients with cervical spondylosis who underwent anterior decompression and reconstruction were reviewed and evaluated retrospectively.There were 44 males and 37 females,with an average age of 52.3 years (range,37-72 years).The distance from anterior margin of the spinal cord to posterior wall of the spinal canal (Da),and medium of the spinal cord to posterior wall of the spinal canal (Dm) in magnetic resonance imaging were measured preoperatively and postoperatively.The recovery rate was calculated comparing the Japanese Orthopaedic Association (JOA) scores before and after operation.Results The average following up was 20.7 months (9-48 months).According to the measure on MRI,preoperative Da and Dm were 11.11±1.59 mm and 6.30±0.84 mm respectively,which were significant different from postoperative Da 11.63±-1.47 mm and Dm 6.62±0.80 mm.The postoperative Da and Dm at C3-4,C4-5,C5-6,C6-7 levels had statistically significant differences compared to preoperative Da and Dm,except for ones at C2-3 level.The significant migration rate was 43.2％(35/81),which reached △Da ＞2 mm or △Dm ＞1.3 mm.Preoperative cervical curvature index (CCI) was 10.0％±6.3％,which was significant different from postoperative CCI 13.5％±6.5％.JOA score increased from 9.7±1.5 preoperatively to 13.7±1.1 at one week postoperatively,and 13.9±1.3 at 6 months postoperatively.But the JOA score decreased at 6 months postoperatively compared with that at 1 week postoperatively in 15 cases.Among them,14 cases got the standard of spinal cord migration based on MRI measurement.No other severe complications were found in these 81 cases.Conclusion Anterior migration of the spinal cord commonly occurred after cervical decompression and reconstruction via anterior approach,and some patients might suffer from the secondary compression of the cervical spinal cord. Key words: Cervical spondylosis; Spinal fusion; Decompression, surgical

Enlarged laminectomy and lateral mass screw fixation for multilevel cervical degenerative myelopathy associated with kyphosis

Background contextEither an anterior approach or a posterior approach, which aims to decompress the spinal cord and restore the sagittal alignment, has been adopted to treat multilevel cervical degenerative myelopathy (CDM) associated with kyphosis. However, there is controversy on the optimal surgical strategy for the treatment of multilevel CDM with kyphotic deformity because of the complications of each surgical approach. PurposeThe purpose of this study was to investigate the surgical efficacy of enlarged laminectomy (removing the inside edge of facet joints and decompressing the nerve foramina) and lateral mass screw fixation for the treatment of multilevel CDM associated with kyphosis. Study designA retrospective radiographic and clinical study to access the efficacy of enlarged laminectomy with lateral mass screw fixation in the treatment of multilevel CDM related to kyphosis. Patient sampleA total of 43 patients (28 men and 15 women; average age, 59.6 years) with multilevel CDM correlated to kyphosis were obtained in the study. Outcome measuresAll radiological data were recorded on computer-based measurement from preoperative or postoperative X-ray, magnetic resonance imaging (MRI), and computed tomography. All neurological parameters were accessed in each patient. MethodsAnalysis consisted of: Japanese Orthopedic Association (JOA) score, recovery rate, curvature index (CI), the expansion degree and drift-back distance of the spinal cord, axial symptom severity, and C5 root palsy. The recovery rate based on the JOA score was calculated for each patient. Cervical CI as well as the expansion degree and drift-back distance of the spinal cord was measured using MRI. Axial symptom severity was quantified by a visual analog scale (VAS). Statistical analysis was performed using paired t test with significance set at p<.05. ResultsEnlarged laminectomy was performed over a mean of 3.97 levels (range, 3–5 levels). Follow-up information was obtained at a mean of 2.8 years (range, 1.5–5 years) after surgery. Analysis of the final follow-up data showed significant differences before and after surgery in the JOA score (t=24.17, p<.001), CI improvement (t=21.89, p<.001), the anteroposterior diameter at the level of maximum compression of the spinal cord (t=9.54, p<.001), and VAS score (t=13.30, p<.001). The mean spinal cord posterior shift was 4.72±1.10 mm (range, 0–6.71 mm). X-rays confirmed that bone grafts were completely fused at a mean of 3 months after surgery. During the follow-up period, only two patients (4.7%) did not obtain complete recovery, four patients (9.3%) experienced axial symptoms; there were no C5 root palsy and instrument failures noted in this series. ConclusionEnlarged laminectomy with fixation for the management of multilevel CDM is demonstrated to be an effective strategy for improving neurological function, restoring the normal cervical lordosis, and decreasing the incidence of axial symptoms and C5 root palsy, but there is a need for randomized controlled studies with long-term follow-up to confirm and clarify these results.

Laminoplasty and laminectomy for cervical sponydylotic myelopathy: a systematic review

Cervical spondylotic myelopathy is frequently encountered in neurosurgical practice. The posterior surgical approach includes laminectomy and laminoplasty. To perform a systematic review evaluating the effectiveness of posterior laminectomy compared with posterior laminoplasty for patients with cervical spondylotic myelopathy. An extensive search of the literature in Pubmed, Embase, and Cochrane library was performed by an experienced librarian. Risk of bias was assessed by two authors independently. The quality of the studies was graded, and the following outcome measures were retrieved: pre- and postoperative (m)JOA, pre- and postoperative ROM, postoperative VAS neck pain, and Ishira cervical curvature index. If possible data were pooled, otherwise a weighted mean was calculated for each study and a range mentioned. All studies were of very low quality. Due to inadequate description of the data in most articles, pooling of the data was not possible. Qualitative interpretation of the data learned that there were no clinically important differences, except for the higher rate of procedure-related complications with laminoplasty. Based on these results, a claim of superiority for laminoplasty or laminectomy was not justified. The higher number of procedure-related complications should be considered when laminoplasty is offered to a patient as a treatment option. A study of robust methodological design is warranted to provide objective data on the clinical effectiveness of both procedures.

Selective posterior enlarged decompression and lateral mass screw fixation for multisegmental cervical spondylotic myelopathy with kyphosis

Objective To investigate the effect and prevention of complications of selective posterior enlarged decompression and lateral mass screw fixation for multisegmental cervical spondylotic myelopathy with kyphosis.Methods From January 2008 to January 2011,43 patients with multisegmental cervical spondylotic myelopathy combined with kyphosis,aged from 42 to 74 years (average,59.6 years),underwent selective posterior enlarged decompression and lateral mass screw fixation.The JOA (Japanese Orthopaedic Association) scoring system and Neck Disability Index (NDI) were applied to evaluate the neurological function and axial neck/shoulder pain before and after surgery,respectively.The Ishihara method was employed to measure the cervical curvature index (CI).The expanding and shifting of the spinal cord was calculated in MRI.Results The decompression range was 3 to 5 segments (average,3.91±0.86 segments).All patients were followed up for 20 to 60 months (average,38 months).There were significant differences between preand post-operative JOA score (8.16±1.11 vs.14.31±1.33),CI (7.36％±9.69％ vs.15.30％±3.18％),anteroposterior diameter of the dural sac at the level of maximum stenosis in MRI [(2.92±1.49) mm vs.(6.10±0.89)mm],and NDI score (19.36±8.61 vs.4.90±2.46).The mean spinal cord posterior shift was (4.59±1.20) mm (range,2.97 to 6.68 mm).The complete bone graft fusion was achieved in all patients 3 to 6 months after surgery.No C5 nerve root palsy or instrument failure occurred.Conclusion The selective posterior enlarged decompression and lateral mass screw fixation is effective in treating multisegmental cervical spondylotic myelopathy with kyphosis,which can improve neurological function,recover and maintain the normal cervical curvature,and decrease the incidences of axial symptoms and C5 nerve root palsy Key words: Cervical vertebrae; Spinal cord compression; kyphosis

The Correlation Study of C5 Nerve Root Palsy and Common Body Position in Posterior Total Laminectomy Decompression and Instrumentation.

To compare both the clinical characteristics and incidence of postoperative cervical nerve root palsy in cervical spondylosis patients treated by posterior total laminectomy, decompression and instrumentation with two different common body positions, traction bed and plaster bed. One hundred and thirty-three patients, with a mean age of 49.5 years suffering from multilevel cervical spondylosis and treated by laminectomy from 2007 to 2009, were reviewed. Overall 30 of 133 (22.56%) patients had C5 palsy, of which 14 (19.44%) out of 72 patients were in the plaster bed group, while 16 of 61 (26.23%) patients were in the traction bed group. The difference was statistically significant (P < 0.05). The cervical curvature index (CCI) reflected both the change of cervical height and the change of the overall cervical curvature. CCI was related with the incidence of C5 nerve root palsy postoperatively. The patients in the traction bed group had a higher nerve root palsy rate and change in cervical alignment because of over traction.

Analysis of axial symptoms after indirect decompression for ossification of the posterior longitudinal ligament of the cervical spine

To study the etiology and clinical significance of axial symptoms after posterior operative procedures for ossification of the posterior longitudinal ligament (OPLL). From February 2005 to February 2010, 76 patients with OPLL treated were retrospectively experienced. There were 34 male and 42 female with average of 52.1 years (range from 37 to 74 years), the average duration of the disease was 32.1 months (range from 11 to 56 months). Nineteen patients underwent traditional laminectomy in group A, 33 patients received open-door laminoplasty in group B and 24 patients underwent lateral mass screw fixation in group C. All patients underwent X-ray examination pre- and post operative, computed tomography were used for diagnosis of OPLL, the recovery rate was calculated using pre- and postoperative Japanese Orthopedic Association (JOA) scores for each patient. Pre- and postoperative cervical curvature index and axial symptoms were measured and compared. χ(2) test and SNK test were used as statistical methods. All patients were followed up for 14 - 35 months, average (21 ± 5) months. Loss of cervical curvature index was 4.2% ± 1.7% in group A, 2.9% ± 2.2% in group B and 2.3% ± 1.9% in group C. The difference was significant in loss of cervical curvature indice between group A and B (q = 2.94, P < 0.01), group A and C (q = 4.23, P < 0.01). The average JOA recovery rate was 58.3% for group A, 64.3% for group B and 66.7% for group C. There was no significant difference in JOA recovery rate among the three groups (P > 0.05). The rate of early evident axial symptoms was 7/19 in group A, 30.3% in group B and 33.3% in group C and the difference was not statistically significant (P > 0.05). The incidence of late evident axial symptoms was 5/19 in group A, 12.1% in group B and 8.3% in group C, the difference was not significant between group B and C (χ(2) = 13.762, P < 0.01), but of statistical difference between group A and B(χ(2) = 6.368, P < 0.01), group A and C (χ(2) = 11.481, P < 0.01). No kyphotic deformity in the group A, no "Close Door" phenomenon in group B and no internal failure in group C. The incidence of early axial symptoms are of no significant difference among the three groups, but late axial symptoms are higher in the laminectomy than other groups, which may be associated with loss of cervical lordosis.

Comparison of incidence of C5 nerve palsy after laminoplasty and laminectomy with internal fixation

Objective To compare the incidence of C5 nerve palsy after laminoplasty and laminectomy with internal fixation for treating multilevel cervical spondylotic myelopathy (MCSM).Methods From January 2005 to June 2010,68 patients with MCSM were treated with laminoplasty (27 patients,group A) or laminectomy with internal fixation (41 patients,group B).There were 21 males and 6 females in group A,aged 33-80 years (average,60.4 years),31 males and 10 females in group B,aged 22-77 years (average,58.7 years).All the patients were followed up for 12-48 months (average,22 months).In both groups,Cobb's method was applied to measure cervical lordotic angle,and Ishihara's method was conducted to measure cervical curvature index (CCI) before and after operation.The incidence of C5 nerve palsy was recorded and compared.Then we further compared preoperative and postoperative the cervical lordosis angle and CCI of 9 patients with C5 nerve palsy (group B1) and 32 patients without C5 nerve palsy (group B2) in group B.Results The incidence of C5 nerve palsy in group A was 3.7％(1/27),while 22.0％(9/41) in group B (x2=4.32,P＜0.05).For all ten patients with C5 nerve palsy,the muscle strengths of paralyzed muscles were recovered to grade 4 or better after being treated with conservative treatment for an average of 14 months.The change rate of preoperative and postoperative CCI in group B1 was 38.07％±18.03％,while 22.81％±12.71％ in group B2.There was a statistical difference between group B1 and group B2 (t=2.88,P＜0.05).Conclusion Compared with laminoplasty,laminectomy with internal fixation has a higher incidence of C5 nerve palsy.The C5 nerve palsy may be associated with postoperative increase of cervical lordosis angle.Moreover,tethering of the C5 root may be one of its important pathomechanisms. Key words: Cervical spondylosis; Laminectomy; Radiculopathy

Cervical laminoplasty using titanium miniplate for multisegmental cervical spondylotic myelopathy

Objective To evaluate the clinical outcome of cervical laminoplasty using titanium miniplate ( AO arch) for the treatment of multisegmental cervical spondylotic myelopathy (MCSM).Methods 21 patients with MCSM were operated by cervical posterior unilateral open-door laminoplasty combined with titanium miniplate internal fixation.The JOA score,sagittal diameter of the spinal canal in the midline (SD) and cervical curvature index according to the measurement of Penning method before surgery and at postoperative follow-up intervals were measured and compared by one-way analysis of variance.Results All patients were followed up for 9 ～48 months.There were no severe adverse events.CT sean showed bony fusion at hinge side since six months after operation.According to the JOA score evaluation system,al final follow-up period,9 cases were excellent,7 good,3 ordinary and 2 cases bad.Recovery rate was 62.5 ％ at final follow-up interval.Cervical SD before surgery and in posloperative one month were (9.2 ± 1.1 )mm,(13.5 ± 1.4) mm,respectively.The difference was significant between them( t =3.02,P ＜ 0.01 ),but there was no improvement since one month postoperatively ( P ＞ 0.05 ).Cervical curvature index was ( 12.6 ± 14.7 ) ° preoperatively,it was ( 17.1 ± 12.4 ) ° at final follow-up interval,indicating that cervical curvature index made obvious progress at final follow-up interval ( t =8.26,P ＜ 0.01 ),but there was no significant change within six months postoperatively ( P ＞ 0.05 ).Conclusions Cervical laminoplasty combined with titanium miniplate can enlarge and maintain cervical SD,ameliorate cervical curvature and neurological function,and it is an ideal alternative treatment for MCSM. Key words: Vertebroplasty; Spinal eanal/SU; Cervical vertebrae/SU; Titanium/TU; Cervical Spondylosis/SU

Clinical significance of posterior spinal cord shifting after open-door laminoplasty

Objective To investigate the clinical significance of posterior spinal cord shifting after two different types of laminoplasty for multilevel cervical myelopathy.Methods From June 2004 to September 2007,65 patients with cervical spondylotic myelopathy were reviewed in this study,including 41 males and 24 females with an average age was 56.3 years (range,39-75).Among them,33 patients underwent selective laminoplasty and 32 patients underwent open-door laminoplasty.There were no significant differences of preoperative JOA scores and cervical curvature index between two groups.After one year follow -up,the posterior shifting of spinal cord,Japanese Orthopaedics Association (JOA) recovery rate,loss of curvature index and axial symptom for each patient were calculated.Results All cases were followed up for average 34 months (range,26-47).There was significant difference of the postoperative posterior shifting between the two groups,which was (1.4±0.6) mm in selective laminoplasty group and (3.3±1.2) mm in opendoor laminoplasty group,respectively.The average JOA recovery rate was 60.5％±21.3％ and 61.1％±17.9％ in selective laminoplasty and open-door laminoplasty group,respectively.There was no significant difference of JOA recovery rate between the two groups.Loss of cervical curvature indices was 3.3％±1.7％ and 3.1％± 2.4％ in selective laminoplasty and open-door laminoplasty group,respectively,with no significant difference between the two groups.The rate of patients with evident axial symptoms was 18.2％ and 33.3％ in selective laminoplasty group and open-door laminoplasty group,and the difference of the scores of cervical axial symptom was statistically significant.Conclusion The degree of the postoperative posterior shifting of the spinal cord in open-door laminoplasty group was greater than that in selective laminoplasty group.The posterior shifting of the spinal is correlated with cord,axial symptom but not the recovery rate and curvature index. Key words: Cervical vertebrae; Spinal cord compression; Decompression, surgical

Influence of Hinge Position on the Effectiveness of Expansive Open-door Laminoplasty for Cervical Spondylotic Myelopathy

A prospective study. To assess the influence of different hinge positions on the clinical results of expansive open-door laminoplasty (EOLP) for cervical spondylotic myelopathy (CSM). EOLP is currently the most widely adopted surgical treatment for CSM, although many long-term clinical follow-up studies have reported that most patients recover satisfactorily after EOLP, there have been numerous reports regarding postoperative complications, such as stubborn axial symptoms and segmental motor paralysis. The hinge position in EOLP plays a decisive role in determining the openness of the door so that affect clinical outcomes, whereas no thorough studies on the hinge positions have been published. A total of 102 consecutive CSM patients who underwent EOLP from February 2006 to February 2007 were enrolled in this randomized controlled trial and assigned alternatively to 1 of 2 treatment groups. Using a random digits table, 57 patients with the hinge located at the inner margin of the lateral mass were classified as wide-open group, whereas 45 patients with the hinge positioned at the lamina margin served as narrow-open group. All patients were followed up over 24 months, clinical results including operation duration, intraoperative bleeding volume, Japanese Orthopaedic Association scores, axial symptoms assessment, and C5 palsy, and radiologic examinations like C2-C7 angle, cervical curvature index, and range of motion were analyzed statistically. In this study, there were no significant differences in terms of operation duration, intraoperative bleeding volume, neural function recovery rate, curvature index, and range of motion. The neural functions were satisfactorily improved after EOLP in both groups (Japanese Orthopaedic Association score developed from 7.2 ± 1.1 to 14.3 ± 1.2 and 8.1 ± 0.9 to 15.1 ± 1.6 with P = 0.01 and 0.02, respectively), whereas the severity of axial symptoms was significantly lower in narrow-open group than in wide-open group (P<0.01). The incidence of C5 palsy in wide-open group was higher than that in narrow-open group (5.3% vs. 0%), even though the difference did not reach statistical significance (1-tailed Fisher exact test, P = 0.17). Our results indicate that proper inward shift of the hinge can ensure effectiveness of surgical decompression, avoid an excessive backward shift of the spinal cord, reduce the incidence of C5 palsy, and alleviate the severity of axial symptoms. In addition, an inward shift should be cautious and contraindicated in patients with fluorosis cervical stenosis, ossification of posterior longitudinal ligament, and ossification of ligament flavum.

Extensive laminectomy for the treatment of ossification of the posterior longitudinal ligament in the cervical spine

To introduce the surgical strategy of extensive laminectomy (with inner 1/4 facet joint resection to expose the origin of the nerve root) and to discuss its benefit for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL) with myelopathy. From January 1998 to December 2005, 82 patients with cervical OPLL underwent extensive laminectomy. We assessed neurological function using the Japanese Orthopedic Association (JOA) scoring system, neck/shoulder pain using a visual analogue scale (VAS), and cervical curvature index (CCI) by the Ishihara method; the expansion degree and the drift-back distance of the spinal cord was calculated using the MRI image. The mean duration of follow-up was 41.6 months. The postoperative JOA score suggested that neurological function improved significantly with a recovery rate of 64%. The incidence rate of transient palsy of the C5 nerve root, which occurred in only 2 patients who recovered to useful function over 2 weeks, was 2.4%. The postoperative VAS score suggested that the pain in the neck/shoulder was mild. Although the postoperative CCI was small, there was no correlation with the length of follow-up period. The increased cross-sectional area of the dural sac at the level of maximum compression together with the significant drift-back distance of the spinal cord suggested that decompression was complete. Extensive laminectomy is effective in treating cervical OPLL, with mild cervical/shoulder pain, low rate of C5 nerve root palsy, and no recurrence of spinal cord compression symptoms.