Comparison of titanium and polyetheretherketone (PEEK) cages in the surgical treatment of multilevel cervical spondylotic myelopathy: a prospective, randomized, control study with over 7-year follow-up

Purpose

Anterior cervical discectomy and fusion (ACDF) with titanium- or polyetheretherketone (PEEK)-cage reconstruction is widely used in the treatment of cervical spondylotic myelopathy (CSM). This study was to compare outcomes of titanium and PEEK cages in the treatment of multilevel CSM.

Methods

Between November 2002 and December 2004, a total of 80 patients with 3-level CSM were randomized in a 1:1 ratio to titanium group and PEEK group. The overall follow-up period of the patients ranged from 86 to 116 months (average 99.7 months). Clinical and radiological results were compared between titanium group and PEEK group.

Results

At the final follow-up, the clinical outcomes including JOA score, NDI score, and the excellent and good rates of clinical outcomes in the PEEK group were better than those in the titanium group. More loss of the Cobb angles and the intervertebral height was observed in the titanium group, resulting in the radiological parameters in the titanium group becoming inferior to the PEEK group at the final follow-up. Cage subsidence rates were 34.5 and 5.4 % in the titanium and PEEK groups, respectively. Fusion was observed in all patients of two groups at the final follow-up. Two patients presented with cage dislocation without clinical symptoms in the titanium group.

Conclusions

In surgical treatment of multilevel CSM, PEEK cage is superior to titanium cage in maintenance of intervertebral height and cervical lordosis, resulting in better clinical outcomes in the long-term follow-up.     

Reduction in range of cervical motion on serial long-term follow-up in patients undergoing oblique corpectomy for cervical spondylotic myelopathy

Purpose

To determine whether motion preservation following oblique cervical corpectomy (OCC) for cervical spondylotic myelopathy (CSM) persists with serial follow-up.

Methods

We included 28 patients with preoperative and at least two serial follow-up neutral and dynamic cervical spine radiographs who underwent OCC for CSM. Patients with an ossified posterior longitudinal ligament (OPLL) were excluded. Changes in sagittal curvature, segmental and whole spine range of motion (ROM) were measured. Nathan’s system graded anterior osteophyte formation. Neurological function was measured by Nurick’s grade and modified Japanese Orthopedic Association (JOA) scores.

Results

The majority (23 patients) had a single or 2-level corpectomy. The average duration of follow-up was 45 months. The Nurick’s grade and the JOA scores showed statistically significant improvements after surgery (p < 0.001). 17 % of patients with preoperative lordotic spines had a loss of lordosis at last follow-up, but with no clinical worsening. 77 % of the whole spine ROM and 62 % of segmental ROM was preserved at last follow-up. The whole spine and segmental ROM decreased by 11.2° and 10.9°, respectively (p ≤ 0.001). Patients with a greater range of segmental movement preoperatively had a statistically greater range of movement at follow-up. The analysis of serial radiographs indicated that the range of movement of the whole spine and the range of movement at the segmental spine levels significantly reduced during the follow-up period. Nathan’s grade showed increase in osteophytosis in more than two-thirds of the patients (p ≤ 0.01). The whole spine range of movement at follow-up significantly correlated with Nathan’s grade.

Conclusions

Although the OCC preserves segmental and whole spine ROM, serial measurements show a progressive decrease in ROM albeit without clinical worsening. The reduction in this ROM is probably related to degenerative ossification of spinal ligaments.     

Measurement of volume-occupying rate of cervical spinal canal and its role in cervical spondylotic myelopathy

Purpose

To compare volume-occupying rate of cervical spinal canal between patients with cervical spondylotic myelopathy (CSM) and normal subjects, and to investigate its significance in cervical spine disease.

Methods

Spiral computed tomography (CT) scan (C4–C6 cervical spine unit) was performed in 20 normal subjects and 36 cases of CSM at a neutral position, and data were transferred to the Advantage Workstation Version 4.2 for assessment. Bony canal area and fibrous canal area in each cross section, and sagittal diameters of cervical spinal canal and cervical spinal body were measured. Volume-occupying rate of cervical spinal canal was calculated using MATLAB. Cervical spinal canal ratio and effective cervical spinal canal ratio were calculated, and Japanese Orthopaedic Association score was used to assess cervical spinal cord function.

Results

Volume-occupying rate of cervical spinal canal at a neutral position was significantly higher in CSM patients as compared to normal subjects (P < 0.01). There was no correlation between cervical spinal canal ratio and JOA score in CSM patients, with a Pearson’s correlation coefficient of 0.171 (P > 0.05). However, sagittal diameter of secondary cervical spinal canal, effective cervical spinal canal ratio and volume-occupying rate of cervical spinal canal were significantly associated to JOA score, with Pearson’s coefficient correlations of 0.439 (P < 0.05), 0.491 (P < 0.05) and ?0.613 (P < 0.01), respectively.

Conclusions

Volume-occupying rate of cervical spinal canal is an objective reflection of compression on cervical spine and spinal cord, and it is associated with cervical spinal cord function. These suggest that it may play a significant role in predicting the development of CSM.     

CT angiography of anterior spinal artery in cervical spondylotic myelopathy

Purpose

To identify anterior spinal artery (ASA) infarct or occlusion by CT angiography (CTA) in patients with cervical spondylotic myelopathy (CSM).

Methods

Fourteen patients with CSM were performed CTA of ASA after admission. T2-weighted hyperintensity of MR image was compared with image of CTA of ASA.

Results

All patients presented spinal canal sagittal diameter compression from 10 to 80 % and different T2-weighted hyperintensity of MR images. No ASA infarct or occlusion was found in CSM patients.

Conclusion

ASA infarct or occlusion is not commonly seen in CSM patients with spinal canal sagittal diameter compression less than 80 %. Pathological changes about T2-weighted hyperintensity of MR image in CSM have no close correlation with ASA infarct.     

Design and preliminary biomechanical analysis of artificial cervical joint complex

Objective

To design an artificial cervical joint complex (ACJC) prosthesis for non-fusion reconstruction after cervical subtotal corpectomy, and to evaluate the biomechanical stability, preservation of segment movements and influence on adjacent inter-vertebral movements of this prosthesis.

Methods

The prosthesis was composed of three parts: the upper/lower joint head and the middle artificial vertebrae made of Cobalt–Chromium–Molybdenum (Co–Cr–Mo) alloy and polyethylene with a ball-and-socket joint design resembling the multi-axial movement in normal inter-vertebral spaces. Biomechanical tests of intact spine (control), Orion locking plate system and ACJC prosthesis were performed on formalin-fixed cervical spine specimens from 21 healthy cadavers to compare stability, range of motion (ROM) of the surgical segment and ROM of adjacent inter-vertebral spaces.

Results

As for stability of the whole lower cervical spine, there was no significant difference of flexion, extension, lateral bending and torsion between intact spine group and ACJC prosthesis group. As for segment movements, difference in flexion, lateral bending or torsion between ACJC prosthesis group and control group was not statistically significant, while ACJC prosthesis group showed an increase in extension (P < 0.05) compared to that of the control group. In addition, ACJC prosthesis group demonstrated better flexion, extension and lateral bending compared to those of Orion plating system group (P < 0.05). Difference in adjacent inter-vertebral ROM of the ACJC prosthesis group was not statistically significant compared to that of the control group.

Conclusion

After cervical subtotal corpectomy, reconstruction with ACJC prosthesis not only obtained instant stability, but also reserved segment motions effectively, without abnormal gain of mobility at adjacent inter-vertebral spaces.     

Alterations in axial curvature of the cervical spine with a combination of rotation and extension in the conventional anterior cervical approach

Purpose

Alterations of three-dimensional cervical curvature in conventional anterior cervical approach position are not well understood. The purpose of this study was to evaluate alignment changes of the cervical spine in the position. In addition, simulated corpectomy was evaluated with regard to sufficiency of decompression and perforation of the vertebral artery canal.

Methods

Fifty patients with cervical spinal disorders participated. Cervical CT scanning was performed in the neutral and supine position (N-position) and in extension and right rotation simulating the conventional anterior approach position (ER-position). Rotation at each vertebral level was measured. With simulation of anterior corpectomy in a vertical direction with a width of 17 mm, decompression width at the posterior wall of the vertebrae and the distance from each foramen of the vertebral artery (VA) were measured.

Results

In the ER-position, the cervical spine was rotated rightward by 37.2° ± 6.2° between the occipital bone and C7. While the cervical spine was mainly rotated at C1/2, the subaxial vertebrae were also rotated by several degrees. Due to the subaxial rotation, the simulated corpectomy resulted in smaller decompression width on the left side and came closer to the VA canal on the right side.

Conclusions

In the ER-position, the degrees of right rotation of subaxial vertebrae were small but significant. Therefore, preoperative understanding of this alteration of cervical alignment is essential for performing safe and sufficient anterior corpectomy of the cervical spine.     

Reciprocal changes in cervical spine alignment after corrective thoracolumbar deformity surgery

Purpose

To identify changes in cervical alignment parameters following surgical correction of thoracolumbar deformity and then assess the preoperative parameters which induce changes in cervical alignment following corrective thoracolumbar deformity surgery.

Methods

A retrospective study of 49 patients treated for thoracolumbar deformity with preoperative planning of an acceptably aligned coronal and sagittal plane in each case. We compared cervical spine parameters in two distinct low [preoperative C7 sagittal vertical axis (SVA) ≤6 cm] and high (preoperative C7 SVA ≥9 cm) C7 SVA groups. Multilinear regression analysis was performed and revealed the relationship between postoperative cervical lordosis and preoperative spinopelvic parameters and surgical plans.

Results

In the lower C7 SVA group, cervical lordosis was significantly increased after thoracic/lumbar deformity correction (p < 0.01). In contrast, the high C7 SVA group showed decreased cervical lordosis postoperatively (p < 0.01). Multilinear regression analysis demonstrated the preoperative parameters (preoperative C2–7 angle, T1 slope, surgical plan for PT and C7 SVA), which determine the postoperative cervical lordosis.

Conclusion

In spinal deformity procedures, preoperative spinal alignment parameters, and surgical plans could affect postoperative cervical spine alignment.     

Anterior surgical options for the treatment of cervical spondylotic myelopathy in a long-term follow-up study

Objective

To provide a basis for the choice of anterior surgery procedures in the treatment of cervical spondylotic myelopathy (CSM) through long-term follow-up.

Methods

A consecutive series of 89 patients with CSM having complete follow-up data were analyzed retrospectively. All patients were treated with anterior cervical discectomy and fusion (ACDF), and anterior cervical corpectomy and fusion (ACCF) from July 2000 to June 2007. The lesions were located in one segment (n = 25), two segments (n = 56), and three segments (n = 8). Preoperative and postoperative, the C2–C7 angle, cervical intervertebral height, radiographic fusion status, result of the adjacent segment degeneration, the Japanese Orthopaedic Association (JOA), and the Short Form 36-item (SF36) questionnaire scores were used to evaluate the efficacy of the surgery.

Results

According to the different compression conditions of the 89 cases, different anterior operation procedures were chosen and satisfactory results were achieved, indicating that direct anterior decompressions were thorough and effective. The follow-up period was 60–108 months, and the average was 79.6 months. The 5-year average symptom improvement rate, effectiveness rate, and fineness rate were 78.36 %, 100 % (89/89), and 86.52 % (77/89), respectively.

Conclusions

For CSM with compression coming from the front side, proper anterior decompression based on the specific conditions could directly eliminate the compression. Through long-term follow-up, the effect of decompression became observable.     

The effects of surgery on locomotion in elderly patients with cervical spondylotic myelopathy

Purpose

This study aimed to evaluate the effects of surgery on locomotor ability in patients with cervical spondylotic myelopathy (CSM) and compare the results between elderly and younger patients.

Methods

A total of 369 consecutive patients who underwent expansive laminoplasty for CSM were prospectively analysed. Patients were divided into two age groups of ≥75 years (elderly group, 76 patients) and <75 years (younger group, 293 patients). Locomotor ability was estimated using part of the functional independence measure (FIM). The sum of gait and stairs items [functional independence measure (locomotion), FIM-L; possible scores, 2–14] and neurological status were estimated using the Japanese Orthopaedic Association (JOA) score (possible score, 0–17). Pre-operative neurological anamnesis was reviewed, and the surgical results of elderly patients with or without co-existing neurological history were evaluated to determine the origin of locomotor disability.

Results

Peri-operative FIM-L and JOA scores were significantly lower in the elderly group than in the younger group, and the opposite was true for improved FIM score. Cerebral infarction and previous lumbar surgery were identified as neurological co-morbidities in the elderly group. However, there was no significant difference in surgical results between elderly patients with and without co-existing neurological disorders.

Conclusions

Decompression surgery can improve locomotor ability and decrease nursing care requirements among elderly patients with CSM. However, other neurological diseases can co-exist in elderly patients, making it difficult to diagnose the origin of locomotor disability. Therefore, detailed peri-operative work-up and timely decompression should be given priority to avoid progression towards fixed locomotor disability.     

Electromyographic characteristics of gait impairment in cervical spondylotic myelopathy

Aim

Gait impairment in cervical spondylotic myelopathy (CSM) is characterised by a number of kinematic and kinetic abnormalities. Surface electromyography (EMG) can evaluate the contributions of individual muscles to a movement pattern and provide insight into the underlying impairments that characterise an abnormal gait. This study aimed to analyse EMG signals from major lower limb muscles in people with CSM and healthy controls during gait.

Methods

Sixteen people with radiologically confirmed CSM and 16 matched healthy controls participated in gait analysis. Surface EMG was recorded during walking from four lower limb muscles bilaterally. The timing of muscle activation, relative amplitudes of each burst of activity and baseline activation during gait, and the muscles’ responses to lengthening as a measure of spasticity were compared using previously validated methods of EMG analysis.

Results

Compared to healthy controls, people with CSM had prolonged duration of activation of biceps femoris (12.5 % longer) and tibialis anterior (12.4 %), prolonged co-activation of rectus femoris and biceps femoris (5.14 %), and impaired scaling of the amplitude of rectus femoris and biceps femoris. Muscle activation in response to lengthening was similar between groups.

Conclusion

The results provide evidence for paresis as a contributory factor to gait impairment in CSM, indicated by impaired amplitude and the need for proximal co-activation to compensate for lack of distal power generation. Poor proprioception may have contributed to prolonged activation of tibialis anterior. Analysis of muscle responses to lengthening suggested that spasticity was not an important contributor. These findings have implications for the assessment and rehabilitation of gait impairment in CSM.     

Mid-term results of computer-assisted cervical reconstruction for rheumatoid cervical spines

Study design

A retrospective single-center study.

Summary and background

We routinely have used C1–C2 transarticular and cervical pedicle screw fixations to reconstruct highly destructed unstable rheumatoid arthritis (RA) cervical lesions. However, there is little data on mid-term results of surgical reconstruction for rheumatoid cervical disorders, particularly, cervical pedicle screw fixation.

Objectives

The purpose of this study was to evaluate the mid-term surgical results of computer-assisted cervical reconstruction for such lesions.

Methods

Seventeen subjects (4 men, 13 women; mean age, 61 ± 9 years) with RA cervical lesions who underwent C1–C2 transarticular screw fixation or occipitocervical fixation, with at least 5 years follow-up were studied. A frameless, stereotactic, optoelectronic, CT-based image-guidance system, was used for correct screw placement. Variables including the Japanese Orthopaedic Association (JOA) score, Ranawat class, EuroQol (EQ-5D), atlantodental interval, and Ranawat values before, and at 2 and 5 years after surgery, were evaluated. Furthermore, screw perforation rates were evaluated.

Results

The lesions included atlantoaxial subluxation (AAS, n = 6), AAS + vertical subluxation (VS, n = 7), and AAS + VS + subaxial subluxation (n = 4). There was significant neurological improvement at 2 years after surgery, as evidenced by the JOA scores, Ranawat class, and the EQ-5D utility weight. However, at 5 years after surgery, there was a deterioration of this improvement. The Ranawat values before, and at 2 and 5 years after surgery, were not significantly different. Major screw perforation rate was 2.1 %. No neural and vascular complications associated with screw insertion were observed.

Conclusions

Subjects with rheumatoid cervical lesions who underwent C1–C2 transarticular screw fixation or occipitocervical fixation using a pedicle screw had significantly improved clinical parameters at 2 years after surgery. However, there was a deterioration of this improvement at 5 years post surgery.     

Sagittal geometry of the middle and lower cervical endplates

Purpose

Construct subsidence is a relatively common complication following anterior cervical fusion. Its occurrence has been revealed to be closely related to endplate-implant contact interface. But current literature focusing on the anatomy of cervical endplate is very scarce. The purpose of this morphometric study was to analyse the sagittal geometry, especially the concavity and slope, of vertebral endplates from C3 to C7 by employing data from CT scans.

Methods

Reformatted CT scans of 97 individuals were analyzed and endplate concavity depth, endplate concavity apex location, as well as endplate slope were measured in midsagittal plane. Those specific parameters were compared among different age and gender groups. Meanwhile, comparison between superior and inferior endplate of each vertebra was also performed.

Results

Age and gender did not influence endplate concavity depth, endplate concavity apex location, or endplate slope significantly (P > 0.05). Endplate concavity depths of superior endplates (range 0.9–1.2 mm) were significantly smaller than those of inferior endplates (range 2.1–2.7 mm). Endplate concavity apex was always located in the posterior half of the endplate, with the superior one ranged from 56 to 67 % and the inferior one 52 to 57 %. Average endplate slopes of superior endplates were between 4.5° and 9.0°, and average inferior endplate slopes ranged from 4.5° to 7.5°. Among all measured segments, C5 had the largest endplate slope values, while C7 the least.

Conclusions

Superior endplate is more flat than its inferior counterpart in middle and lower cervical spine, and the concavity apex is always located in the posterior half of the endplate. Endplate slope is correlated with cervical curvature, greater slope implying more significant lordosis. These sagittal endplate geometrical parameters should be taken into consideration when investigating implant subsidence following anterior cervical fusion.     

Early neurological recovery course after surgical treatment of cervical spondylotic myelopathy: a prospective study with 2-year follow-up using three different functional assessment tests

Purpose

Though surgical decompression is today a common option for treatment of cervical spondylotic myelopathy (CSM), little is known about the exact postoperative early neurological recovery course. The purpose of this study was to analyze the functional recovery, its dynamics, its intensity and its pattern, in the early postoperative period after surgical decompression for CSM.

Methods

A prospective non-controlled observational study was performed from March 2006 to July 2008, and included consecutive patients with CSM who underwent surgical decompression. Functional assessments were done before the operation, at 1 month, 6, 12, 18 and 24 months after surgery using three tests: the Japanese Orthopaedic Association (JOA) test, the nine-hole peg test (9HPT) and the Crockard walking test.

Results

Sixty-seven patients were included (mean age of 61 years). The global JOA score improved after surgery, reaching statistical significance at 1 month (from 11.5 ± 2.6 to 13.6 ± 2.0 points, p = 0.0078), then settling to a plateau till the end of follow-up at 24 months (12.7 ± 2.6 points). The 9HPT and the Crockard test did not show any significant improvement after surgery.

Conclusions

Neurological recovery after surgical decompression has been proved to be very fast during the first month, but stabilizes afterwards. The JOA score is the best assessment to reveal neurological improvement in the early recovery course.     

Measurement of long-term outcome in patients with cervical spondylotic myelopathy treated surgically

Purpose

The Myelopathy Disability Index and the Neck Disability Index are widely used to assess outcome in cervical spine surgery. Short Form (SF) 36 is a generic measure of health which can be used to measure health gains across a wide variety of conditions. The aim of the current study is to assess long-term outcomes using these measures in a cohort of patients with cervical spondylotic myelopathy (CSM).

Methods

Cohort study with prospective data collection. Patients with CSM being offered decompressive surgery were asked to complete a set of generic and condition-specific outcome measures. This was repeated post-operatively at 3, 12, 24 and 60 months. SF-36 was used as a generic outcome measure and the Myelopathy Index, Neck Disability Score and visual analogue scores for arm, neck and hand pain, paraesthesia and dysthaesia were used as condition-specific outcome measures.

Results

Significant improvements in all outcome measures were seen in 70 % of the cohort. For SF-36, pre-operative scores were lower than age-matched controls in all domains and significant improvements were seen 3 months following surgery. This improvement in outcome was maintained at 5 years follow-up in approximately two-thirds of those with initial improvement.

Conclusion

We have used generic and condition-specific outcome measures of health and shown that in patients with CSM treated surgically, up to 70 % can expect improvement in their quality of life. These outcome measures are easy to collect and provide objective evidence of changes in quality of life and disability and can help quantify the potential health gains that can be achieved.     

Cervical extension magnetic resonance imaging in evaluating cervical spondylotic myelopathy

Background

Cervical spondylotic myelopathy (CSM) may be caused by static and dynamic spinal cord compression, particularly during neck extension. Dynamic compression may be better evaluated with dynamic magnetic resonance (MR) images. We performed a retrospective study to determine the clinical indication for dynamic MR imaging, and conducted a survey regarding image interpretation by clinicians.

Method

A total of 32 patients (M:F?=?20:12, 60.1?±?10.7 years) who had undergone neutral/extension cervical MR imaging were included. The study population consisted of 22 patients with signs of cervical myelopathy (M group) and 10 patients without signs of myelopathy (NM group). The number of compression levels (complete obliteration of the anterior and posterior subarachnoid space) was assessed at each level in mid-sagittal, T2-weighted, neutral and extension MR images. Reproduced images from 22 patients in the M group were randomly arranged, and four experienced spine surgeons at four different institutes interpreted them to reach a clinicians’ agreement. The agreements were then assessed with inter-rater correlation coefficients (ICC).

Results

Analysis with extension MR images found an increased number of compression levels in 23/32 (72 %) of patients; 20/22 in the M group and 3/10 in the NM group (p?<?0.01, chi-squared test), as compared to findings of the neutral MR images. Clinical factors for increased compression levels in extension MR images were age (p?<?0.01, 63.3?±?10.0 years vs. 51.9?±?8.1) and signs of myelopathy (p?<?0.01, odds ratio, 23.33). Clinician agreement was improved with extension MR images; ICC was 0.67 with neutral and 0.81 with extension MR images.

Conclusions

The evaluation of CSM may be improved with dynamic MR images. Dynamic MR scanning may be considered for elderly patients with signs of myelopathy, but an interpretation for asymptomatic spinal compression based exclusively on extension MR image should be made with caution.     

Dural tear and resultant cerebrospinal fluid leaks after cervical spinal trauma

Purpose

Traumatic cervical spinal cord injuries (SCIs) frequently develop dural tears and resultant cerebrospinal fluid (CSF) leaks. They are not usually identified with advanced imaging, and there are no reports on managing CSF leaks after cervical trauma. Hence, the authors evaluated the incidence of CSF leaks after cervical SCIs and described how to predict and manage CSF leaks.

Methods

An observational retrospective study was done confirming intraoperative CSF leaks among 53 patients with anterior cervical surgery after cervical spine trauma between 2004 and 2011.

Results

Seven patients (13.2 %) had dural tears and resultant CSF leaks intraoperatively (M:F ratio of 6:1; mean age, 44.7 years). An initial poor American Spinal Injury Association (ASIA) scale was significantly associated with CSF leaks (p = 0.009). From magnetic resonance imaging (MRI), disruption of the ligamentum flavum was correlated with CSF leaks (p = 0.02). Intraoperative application of fibrin glue on the operated site, postoperative management through the early removal of the wound drain within the first 24 h and early rehabilitation were performed in patients with CSF leaks without perioperative insertion of a lumbar drain. During the follow-up period, none of the patients developed CSF-leak-related complications.

Conclusion

The incidence of CSF leaks after traumatic cervical SCI is relatively higher than that of degenerative cervical spinal surgery. An initial poor neurological status and disruption of the ligamentum flavum on the MRI in patients were predictable factors of dural tears and CSF leaks.     

Evaluation of a new type of titanium mesh cage versus the traditional titanium mesh cage for single-level, anterior cervical corpectomy and fusion

Study design

A retrospective review of prospectively collected data in an academic institution.

Objective

To evaluate the safety and efficacy of a new type of titanium mesh cage (TMC) in single-level, anterior cervical corpectomy and fusion (ACCF).

Methods

Fifty-eight patients consecutive with cervical spondylotic myelopathy (CSM) from cervical degenerative spondylosis and isolated ossification of the posterior longitudinal ligament were treated with a single-level ACCF using either a new type of TMC (28 patients, group A) or the traditional TMC (30 patients, group B). We evaluated the patients for TMC subsidence, cervical lordosis (C2–C7 Cobb and Cobb of fused segments) and fusion status for a minimum of 30 months postoperatively based on spine radiographs. In addition, neurologic outcomes were evaluated using the Japanese Orthopedic Association (JOA) scores. Neck pain was evaluated using a 10-point visual analog scale (VAS).

Results

The loss of height of the fused segments was less for group A than for group B (0.8 ± 0.3 vs. 2.8 ± 0.4 mm) (p < 0.01); also, there was a lower rate of severe subsidence (≥3 mm) in group A (4 %, 1/28) than in group B (17 %, 5/30) (p < 0.01). There were no differences in the C2–C7 Cobb and Cobb of fused segments between the groups preoperatively or at final follow-up (p > 0.05), but the Cobb of fused segments immediately postoperative were significantly less for group B than for group A (p < 0.01). All patients, however, had successful fusion (100 %, each). Both groups had marked improvement in the JOA score after operation (p < 0.01), with no significant differences in the JOA recovery ratio (p > 0.05). The postoperative VAS neck pain scores for group A were significantly less than that for group B (p < 0.05); severe subsidence was correlated with neck pain.

Conclusions

The new type of TMC provides comparable clinical results and fusion rates with the traditional TMC for patients undergoing single-level corpectomy. The new design TMC decreases postoperative subsidence (compared to the traditional TMC); the unique design of the new type of TMC matches the vertebral endplate morphology which appears to decrease the severity of subsidence-related neck pain in follow-up.     

Footprint mismatch in total cervical disc arthroplasty

Purpose

Cervical disc arthroplasty has become a commonplace surgery for the treatment of cervical radiculopathy and myelopathy. Most manufacturers derive their implant dimensions from early published cadaver studies. Ideal footprint match of the prosthesis is essential for good surgical outcome.

Methods

We measured the dimensions of cervical vertebrae from computed tomography (CT) scans and to assess the accuracy of match achieved with the most common cervical disc prostheses [Bryan (Medtronic), Prestige LP (Medtronic), Discover (DePuy) Prodisc-C (Synthes)]. A total of 192 endplates in 24 patients (56.3 years) were assessed. The anterior–posterior and mediolateral diameters of the superior and inferior endplates were measured with a digital measuring system.

Results

Overall, 53.5 % of the largest device footprints were smaller in the anterior–posterior diameter and 51.1 % in the mediolateral diameter were smaller than cervical endplate diameters. For levels C5/C6 and C6/C7 an inappropriate size match was noted in 61.9 % as calculated from the anteroposterior diameter. Mismatch at the center mediolateral diameter was noted in 56.8 %. Of the endplates in the current study up to 58.1 % of C5/C6 and C6/C7, and up to 45.3 % of C3/C4 and C4/C5 were larger than the most frequently implanted cervical disc devices.

Conclusion

Surgeons and manufacturers should be aware of the size mismatch in currently available cervical disc prostheses, which may endanger the safety and efficacy of the procedure. Undersizing the prosthetic device may lead to subsidence, loosening, heterotopic ossification and biomechanical failure caused by an incorrect center of rotation and load distribution, affecting the facet joints.     

Results of surgical treatment of cervical spondylotic myelopathy in patients aged 75 years or more: a comparative study of operative methods

Introduction

The number of surgical procedures in elderly patients has been increasing as the population has grown older; recently, spine surgeons have been more likely to encounter elderly patients with cervical myelopathy in need of surgical treatment. There are many reports about surgical treatment of elderly patients with cervical spondylotic myelopathy (CSM); however, there are no studies about the proper selection of surgical methods and comparison of their results in CSM patients aged ≥75 years. The objective of this study was to review the results of operative methods in CSM patients aged ≥75 years.

Methods

Forty-three consecutive cases with an average age of 79 years that underwent surgical treatment were included in this study. The neurological severity was assessed using the Japanese Orthopaedic Association score for cervical myelopathy (JOA). The JOA scores were evaluated before surgery and at final follow-up. There were 21 laminoplasty procedures (from C3 to C7), 13 selective laminoplasty procedures (one above and one below the affected intervertebral level), and nine anterior decompression and fusion procedures. A selective laminoplasty was performed in cases with general complications and was diagnosed as one intervertebral level both clinically and electrophysiologically. Surgical results were compared among the three treatment groups.

Results

The average preoperative JOA score was 7.7 points and the average JOA recovery rate was 45 %. There were three cases of C5 palsy and one wound infection. Operative time and intraoperative bleeding in the selective laminoplasty group were significantly smaller than those in the other groups. There was no significant difference in the JOA recovery rates among the groups.

Conclusions

Selective laminoplasty is less invasive and the surgical results in our study were almost good. It also has good short-term results. However, the indication for surgery has to be selected carefully in elderly CSM patients.     

Larynx-Preserving Limited Resection and Free Jejunal Graft For Carcinoma of the Cervical Esophagus

Background

There is no generally accepted treatment strategy for cervical cancer. The aim of this study was to evaluate the safety and efficacy of larynx-preserving limited resection with free jejunal graft for cervical esophageal cancer.

Methods

We retrospectively reviewed data of 58 patients with cervical esophageal cancer who underwent limited resection and free jejunal graft with or without laryngeal preservation. Among them, 45 patients received neoadjuvant treatment.

Results

Larynx-preserving surgery was conducted in 33 of the 58 patients (56.9 %). A higher proportion of patients who underwent laryngopharyngectomy with cervical esophagectomy (larynx-nonpreserving group) had cT4 tumors than those who underwent larynx-preserving cervical esophagectomy (larynx-preserving group) (72 vs. 12 %). The overall incidence of postoperative complications was similar in the two groups (56 vs. 52 %). The 5-year survival rate was 44.9 % for the entire group. Laryngeal preservation did not reduce overall survival compared with the larynx-nonpreserving operation (5-year survival rate: 57.8 vs. 25.8 %). Multivariate analysis identified the number of metastatic lymph nodes as the only independent prognostic factor.

Conclusions

The present study demonstrated that larynx-preserving limited resection with free jejunal graft is feasible. Also, this approach did not worsen the prognosis compared with the larynx-nonpreserving operation. Limited resection with free jejunal graft and laryngeal preservation is a promising treatment strategy for cervical esophageal cancer.