Long-term follow-up results of the Cloward procedure for cervical spondylotic myelopathy

Purpose

To assess the long-term results of anterior cervical discectomy and fusion using the Cloward procedure for the treatment of cervical spondylotic myelopathy, and to identify possible clinical outcome predictors.

Methods

A total of 14 cases with a 10-year postoperative follow-up were available (82.4 % of the surviving patients). Patients underwent preoperative and postoperative neurological examination. The symptom severity was graded according to the Nurick scale. MRI measurements were obtained preoperatively. Cervical spine radiographs were obtained preoperatively and at the time of follow-up.

Results

The mean improvement of the clinical status of patients on the Nurick scale was 1.43 ± 0.51 (range 1–2) with respect to the baseline values (p < 0.001), with a 62.5 % recovery rate. A positive association between the improvement of the Nurick scale and the length of follow-up was detected with an age-adjusted univariate analysis (p = 0.042). The Nurick grade improvement was also directly related to preoperative lower limb hyperreflexia (p = 0.039), spasticity (p = 0.017), and bladder dysfunction (p = 0.048). At the time of follow-up, an adjacent discopathy was noted above and below the operated level(s) in eight and six patients, respectively.

Conclusions

The Cloward technique is a safe and effective procedure for the treatment of cervical spondylotic myelopathy. The patients’ preoperative neurological status and the length of follow-up affect the grade of postoperative ambulatory improvement.     

Multilevel oblique corpectomy for cervical spondylotic myelopathy preserves segmental motion

Purpose

To document the neurological outcome, spinal alignment and segmental range of movement after oblique cervical corpectomy (OCC) for cervical compressive myelopathy.

Methods

This retrospective study included 109 patients—93 with cervical spondylotic myelopathy and 16 with ossified posterior longitudinal ligament in whom spinal curvature and range of segmental movements were assessed on neutral and dynamic cervical radiographs. Neurological function was measured by Nurick’s grade and modified Japanese Orthopedic Association (JOA) scores. Eighty-eight patients (81%) underwent either a single- or two-level corpectomy; the remaining (19%) undergoing three- or four-level corpectomies. The average duration of follow-up was 30.52 months.

Results

The Nurick’s grade and the JOA scores showed statistically significant improvements after surgery (p < 0.001). The mean postoperative segmental angle in the neutral position straightened by 4.7 ± 6.5°. The residual segmental range of movement for a single-level corpectomy was 16.7° (59.7% of the preoperative value), for two-level corpectomy it was 20.0° (67.2%) and for three-level corpectomies it was 22.9° (74.3%). 63% of patients with lordotic spines continued to have lordosis postoperatively while only one became kyphotic without clinical worsening. Four patients with preoperative kyphotic spines showed no change in spine curvature. None developed spinal instability.

Conclusions

The OCC preserves segmental motion in the short-term, however, the tendency towards straightening of the spine, albeit without clinical worsening, warrants serial follow-up imaging to determine whether this motion preservation is long lasting.     

Expandable titanium cages for anterior column cervical reconstruction and their effect on sagittal profile: a review of 48 cases

Background

Expandable cervical cages have been utilised successfully to reconstruct the cervical spine for various conditions. However, to date there are only limited data on their influence on cervical sagittal profile. In this retrospective study, we present our experience with performing anterior cervical corpectomy in one or two levels using expandable titanium cages in order to achieve stable reconstruction and restoration of cervical lordosis.

Methods

A case series of data from 48 consecutive patients (20 men, 28 women; mean age 61 years) operated upon in a 5-year-period is retrospectively reviewed. Standard anterior single- or two-level cervical corpectomy, fusion and spinal reconstruction were performed, including placement of an expandable titanium cage and an anterior cervical plate. The mean follow-up was 23 months (range, 8–42 months). Outcome was measured by clinical examinations and visual analogue scale (VAS) scale; myelopathy was classified according the Nurick grading system. Radiographic analysis comprised several parameters, including segmental Cobb angle, cervical lordosis, subsidence ratio and sagittal cage angle. Computed tomography was done 1 and 2 years after surgery; cervical spine radiographs were obtained 3, 6, 12 and 24 months after surgery.

Results

In 38 patients (79 %) osseous fusion or stability of construct could be demonstrated in the 2-year follow up examination. The mean restoration of segmental Cobb angle as well as cervical lordosis amounted to 7.6° and 5.4° respectively, both being statistically significant. Furthermore, a profound correction (10° or more) of the sagittal cervical curve was shown in 15 patients.

Conclusion

Regarding the restoration of the physiological sagittal cervical profile, expandable cervical cages seem to be efficient and easy to use for cervical spine reconstruction after anterior corpectomy. Donor-site-related complications are avoided, fast and strong reconstruction of the anterior column is provided, resulting in satisfactory fusion rates after 2 years.     

Coexisting lumbar and cervical stenosis (tandem spinal stenosis): an infrequent presentation. Retrospective analysis of single-stage surgery (53 cases)

Study design

Retrospective analysis of 53 patients who underwent single stage simultaneous surgery for tandem spinal stenosis (TSS) at single centre.

Objective

To discuss the presentation of combined cervical and lumbar (tandem) stenosis and to evaluate the safety and efficacy of single-stage simultaneous surgery.

Summary of background data

Combined stenosis is an infrequent presentation with mixed presentation of upper motor neuron and lower motor neuron signs. Scarce literature on its presentation and management is available. There is a controversy in the surgical strategy of these patients. Staged surgeries are frequently recommended and only few single-stage surgeries reported.

Methods

All the patients were clinico-radiologically diagnosed TSS. Surgeries were performed in single stage by two teams. Results were evaluated with Nurick grade, modified Japanese Orthopedic Association score (mJOA), oswestry disability index (ODI), patient satisfaction index, mJOA recovery rate, blood loss and complication.

Results

The mJOA cervical and ODI score improved from a mean 8.86 and 68.15 preoperatively to 13.00 and 30.11, respectively, at 12 months and to 14.52 and 24.03 at final follow-up. The average mJOA recovery rate was 48.23 ± 26.90 %. Patient satisfaction index was 2.13 ± 0.91 at final follow-up. Estimated blood loss of ≤400 ml and operating room time of <150 min showed improvement of scores and lessened the complications. In the age group below 60 years, the improvement was statistically significant in ODI (p = 0.02) and Nurick’s grade (p = 0.03) with average improvement in mJOA score.

Conclusion

Short-lasting surgery, single anaesthesia, reduced morbidity and hospital stay as well as costs, an early return to function, high patient satisfaction rate with encouraging results justify single-stage surgery in TSS. Age, blood loss and duration of surgery decide the complication rate and outcome of surgery. Staged surgery is recommended in patients above the age of 60 years.     

Cervical arthroplasty with Discover prosthesis: clinical outcomes and analysis of factors that may influence postoperative range of motion

Purpose

The aim of this current study was to analyze the clinical outcomes after Discover cervical disc replacement and its effects on maintaining cervical lordosis and range of motion (ROM). The possible factors influencing postoperative ROM were analyzed.

Method

27 men and 28 women with a mean age of 46.4 ± 8.7 years were prospectively followed up for 2 years. Clinical outcomes were assessed using Japanese Orthopedic Association (JOA), Neck Disability Index (NDI), visual analog scale (VAS) and Odom’s criteria. Radiographic information including segment and overall alignment, functional spinal unit (FSU) and overall ROM, and disc heights were prospectively collected during the follow-up. The correlations between the postoperative FSU ROM at last follow-up and influencing factors were analyzed.

Results

Mean NDI, JOA and VAS scores showed statistical improvements at last follow-up. Anterior migration of the prosthesis was detected in six cases. Heterotopic ossification was observed in ten patients. Mean FSU angle, endplate angle of the treated level and mean overall cervical alignment were all improved significantly at last follow-up (P < 0.001). However, mean FSU ROM of the treated segment significantly decreased postoperatively (P = 0.008), while mean overall ROM showed no significant differences. A significant correlation was found between preoperative FSU ROM and postoperative FSU ROM by the Pearson correlation coefficient (r = 0.325, P = 0.034). Multiple linear regression analysis confirmed that preoperative FSU ROM contributed independently to a model with a coefficient of determination of 0.37 (P = 0.034).

Conclusions

In the 2 years follow-up, the Discover cervical disc arthroplasty has provided satisfactory clinical outcomes. It was able to substantially restore segment and overall cervical alignment while partially maintaining segment and overall cervical ROM. Additionally, we found that postoperative FSU ROM positively correlated with preoperative FSU ROM.     

Range of motion of thoracic spine in sagittal plane

Study design

Imaging study of thoracic spine.

Objective

The purpose of this study was to investigate dynamic alignment and range of motion (ROM) at all segmental levels of thoracic spine.

Summary of background data

Thoracic spine is considered to have restricted ROM because of restriction by the rib cage. However, angular movements of thoracic spine can induce thoracic compressive myelopathy in some patients. Although few previous studies have reported segmental ROM with regard to sagittal plane, these were based on cadaver specimens. No study has reported normal functional ROM of thoracic spine.

Methods

Fifty patients with cervical or lumbar spinal disease but neither thoracic spinal disease nor compression fracture were enrolled prospectively in this study (34 males, 16 females; mean age 55.4 ± 14.7 years; range 27–81 years). After preoperative myelography, multidetector-row computed tomography scanning was performed at passive maximum flexion and extension position. Total and segmental thoracic kyphotic angles were measured and ROM calculated.

Results

Total kyphotic angle (T1/L1) was 40.2° ± 11.4° and 8.5° ± 12.8° in flexion and extension, respectively (P < 0.0001). The apex of the kyphotic angle was at T6/7 in flexion. Total ROM (T1/L1) was 31.7° ± 11.3°. Segmental ROM decreased from T1/2 to T4/5 but increased gradually from T4/5 to T12/L1. Maximum ROM was at T12/L1 (4.2° ± 2.1°) and minimum at T4/5 (0.9° ± 3.0°).

Conclusions

Thoracic spine showed ROM in sagittal plane, despite being considered a stable region. These findings offer useful information in the diagnosis and selection of surgical intervention in thoracic spinal disease.     

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.     

Biomechanical evaluation of a low profile, anchored cervical interbody spacer device in the setting of progressive flexion-distraction injury of the cervical spine

Introduction

Anterior cervical decompression and fusion is a well-established procedure for treatment of degenerative disc disease and cervical trauma including flexion-distraction injuries. Low-profile interbody devices incorporating fixation have been introduced to avoid potential issues associated with dissection and traditional instrumentation. While these devices have been assessed in traditional models, they have not been evaluated in the setting of traumatic spine injury. This study investigated the ability of these devices to stabilize the subaxial cervical spine in the presence of flexion-distraction injuries of increasing severity.

Methods

Thirteen human cadaveric subaxial cervical spines (C3–C7) were tested at C5–C6 in flexion–extension, lateral bending and axial rotation in the load-control mode under ±1.5 Nm moments. Six spines were tested with locked screw configuration and seven with variable angle screw configuration. After testing the range of motion (ROM) with implanted device, progressive posterior destabilization was performed in 3 stages at C5–C6.

Results

The anchored spacer device with locked screw configuration significantly reduced C5–C6 flexion–extension (FE) motion from 14.8 ± 4.2 to 3.9 ± 1.8°, lateral bending (LB) from 10.3 ± 2.0 to 1.6 ± 0.8, and axial rotation (AR) from 11.0 ± 2.4 to 2.5 ± 0.8 compared with intact under (p < 0.01). The anchored spacer device with variable angle screw configuration also significantly reduced C5–C6 FE motion from 10.7 ± 1.7 to 5.5 ± 2.5°, LB from 8.3 ± 1.4 to 2.7 ± 1.0, and AR from 8.8 ± 2.7 to 4.6 ± 1.3 compared with intact (p < 0.01). The ROM of the C5–C6 segment with locked screw configuration and grade-3 F-D injury was significantly reduced from intact, with residual motions of 5.1 ± 2.1 in FE, 2.0 ± 1.1 in LB, and 3.3 ± 1.4 in AR. Conversely, the ROM of the C5–C6 segment with variable-angle screw configuration and grade-3 F-D injury was not significantly reduced from intact, with residual motions of 8.7 ± 4.5 in FE, 5.0 ± 1.6 in LB, and 9.5 ± 4.6 in AR.

Conclusions

The locked screw spacer showed significantly reduced motion compared with the intact spine even in the setting of progressive flexion-distraction injury. The variable angle screw spacer did not sufficiently stabilize flexion–distraction injuries. The resulting motion for both constructs was higher than that reported in previous studies using traditional plating. Locked screw spacers may be utilized with additional external immobilization while variable angle screw spacers should not be used in patients with flexion-distraction injuries.     

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.     

Sagittal alignment of the cervical spine in adolescent idiopathic scoliosis treated by posteromedial translation

Purpose

To analyze postoperative changes in the cervical sagittal alignment (CSA) of patients with AIS treated by posteromedial translation.

Methods

49 patients with thoracic AIS underwent posterior arthrodesis with hybrid constructs, combining lumbar pedicle screws and thoracic universal clamps. Posteromedial translation was the main correction technique used. 3D radiological parameters were measured from low-dose biplanar radiographs. CSA was assessed using the C2C6 angle, and the central hip vertical axis (CHVA) was used as a reference axis to evaluate patients’ balance.

Results

Preoperatively, 58 % of patients had thoracic hypokyphosis, and 79 % had a kyphotic CSA. Significant correlation was found (r = 0.45, P = 0.01) between thoracic hypokyphosis and cervical kyphosis. Increase in T4–T12 thoracic kyphosis (average 14.5° ± 10°) was associated with significant decrease in cervical kyphosis in the early postoperative period. The CSA further improved spontaneously during follow-up by 7.6° (P < 0.0001). Significant positive correlation (r = 0.32, P = 0.03) was found between thoracic and cervical improvements. At latest follow-up, 94 % of the patients were normokyphotic and 67 % had a CSA in the physiological range. Sagittal balance of the thoracolumbar spine was not significantly modified postoperatively. However, the procedure significantly changed the position of C2 in regard to the CHVA (C2–CHVA), which reflects headposition (P = 0.012). At last follow-up, the patients sagittal imbalance was not significantly different from the preoperative imbalance (P = 0.34).

Conclusions

Thoracic hypokyphosis and cervical hypolordosis, observed in AIS, can be improved postoperatively, when the posteromedial translation technique is used for correction. The cervical spine remains adaptable in most patients, but the proportion of patients with physiological cervical lordosis at final follow-up remained low (24.5 %).     

The correlation between cervical range of motion and misplacement of cervical pedicle screws during cervical posterior spinal fixation surgery using a CT-based navigation system

Purpose

The aim of this study was to analyze the correlation between cervical range of motion and cervical pedicle screw (CPS) misplacement in cervical posterior spinal fusion surgery using a CT-based navigation system.

Methods

A total of 46 consecutive patients with cervical posterior spinal fusion surgery using CPSs were evaluated retrospectively. We analyzed the cervical range of motion (ROM) and the misplacement of CPSs that were placed using either separate or single-time multilevel registration with a CT-based navigation system to determine the optimum registration procedure. The screw-inserted vertebra was indicated as Registered vertebra-Pedicle Screw inserted vertebra (Re-PS) = 0, 1, 2, or 3 depending on its distance (level) from the registered vertebra. Grades 0 (no perforation) and 1 (perforations <2 mm) were categorized as “no misplacement.” Grades 2 (perforations ≧2 mm but < 4 mm) and 3 (perforations ≧ 4mm) were categorized as “misplacement.” We analyzed the correlations between CPS misplacement and Re-PS, and between CPS misplacement and preoperative cervical ROM.

Results

Our analysis included 196 screws in patients having a mean age of 53.2 years (range 5–84 years). Level of insertion relative to registration was Re-PS = 0 in 129 screws, Re-PS = 1 in 53, Re-PS = 2 in 10 and Re-PS = 3 in 4. The misplacement rates were 12.2 % (24 screws) overall, 6.2 % in Re-PS = 0, 22.6 % in Re-PS = 1, 20 % in Re-PS = 2, and 50 % in Re-PS = 3. The rate of CPS misplacement increased significantly with a Re-PS = 1 and a Re-PS = 2 and 3 compared to a Re-PS = 0. There was a significant difference in the cervical ROM in each grade and both misplacement groups: 1.8 in Grade 0, 2.3 in Grade 1, 7.8 in Grade 2, 12.9 in Grade 3, 11 in the misplacement group and 1.9 in the no misplacement group.

Conclusions

The precision of CPS placement in CT-based navigation surgery was evaluated. The misplacement rate in single-time multilevel registration increased to 23.4 % compared to 6.2 % for separate registration. As the distance increased between the registered level and the level of CPS insertion, the preoperative cervical ROM and the rate of CPS misplacement significantly increased. Thus, the rate of misplacement of CPSs is reduced when performing separate registration. Furthermore, when there is greater preoperative cervical ROM, separate registration would likely improve the safety and accuracy of CPS insertion.     

Anschlusssegmentbeweglichkeit nach monosegmentaler Bandscheibenprothesenimplantation und monosegmentaler Fusion Segment L4/5

Background

Preservation of movement at the treated segment and possible reduction of adjacent segment effects is assumed to be an advantage of non-fusion technologies over fusion. The aim of this study was to compare the segmental range of motion (ROM) at the operative level, the cranial and caudal adjacent levels and the global lumbar spine ROM (L2-S1) after monosegmental fusion and total disc replacement (TDR).

Patients and methods

Radiographic data was collected from 27 patients with level 1 degenerative disc disease operated at level L4/5. The ROM was assessed at the index level (L4/5), the cranial and caudal adjacent level and for the lumbar spine (L2-S1).

Results

In the TDR group no significant changes of lumbar spine ROM (L2–S1) and segmental ROM (index level, cranial and caudal adjacent level) were noticed. In the fusion group there was a significant reduction of lumbar ROM (L2-S1) and index level ROM. Additionally the relative ROM in the adjacent caudal segment significantly increased while no changes were seen in the cranial segment.

Conclusion

The relative ROM was significantly increased in monosegmental fusion at level L4/5 compared to TDR. To what extent this fact may result in early adjacent segment degeneration in cases of fusion compared to TDR is still unknown.     

Clinical and radiographic outcomes of dynamic cervical implant replacement for treatment of single-level degenerative cervical disc disease: a 24-month follow-up

Purpose

To determine the role of dynamic cervical implant (DCI) replacement for single-level degenerative cervical disc disease in Chinese patients.

Methods

Thirty patients with single-level degenerative cervical disc disease were prospectively enrolled between April 2010 and August 2010 (12 women, 18 men; mean age 56.5 years). All patients underwent anterior cervical decompression, DCI replacement, clinical and radiological assessments preoperatively and at 1, 6, 12, and 24 months postoperatively, and Japanese Orthopaedic Association (JOA), Visual Analogue Scale (VAS), Neck Disability Index (NDI), and Short Form 36 (SF-36) scores. Lateral neutral radiographs provided the intervertebral space height. Lateral dynamic radiographs were taken to measure the range of motion (ROM) of the cervical spine and functional spinal unit (FSU) of the treated segment. We compared the amount of motion of the adjacent vertebral endplate and the intrinsic motion of the implant and calculated a correlation analysis.

Results

DCI showed good clinical and radiographic outcomes. At the final follow-up, JOA, VAS, NDI, and SF-36 average scores improved significantly. The intervertebral space height increased slightly after operation and was maintained during follow up. The ROM of the cervical spine and FSU decreased at early follow-up, but recovered to the preoperative level within 1–2 years. There was a high index of linear correlation between the motion of the adjacent vertebral endplate and the intrinsic motion of the implant.

Conclusions

DCI provided elastic dynamic stability for the targeted segment, and restored and sustained intervertebral space height and ROM of the cervical spine.     

Changes in cervical spine curvature after uninstrumented one- and two-level corpectomy in patients with spondylotic myelopathy

OBJECTIVE: We studied changes in the cervical spine curvature in patients with cervical spondylotic myelopathy who underwent one- or two-level central corpectomy and iliac bone grafting without the use of instrumentation. METHODS: Curvature of the fused segment and of the whole cervical spine was evaluated on preoperative and follow-up x-rays in 93 patients (30 underwent one-level corpectomy, and 63 underwent two-level corpectomy). In 59 patients, the changes in the cervical spine curvature were studied using one follow-up x-ray; in the other 34 patients, the changes were studied on x-rays obtained at two or more follow-up visits. The sagittal alignment of the fused segment was categorized as lordotic (>+5 degrees), straight (+5 to -5 degrees) or kyphotic (>-5 degrees). The whole spine curvature also was recorded as lordotic, straight, or kyphotic. RESULTS: At a mean follow-up of 22.2 months (range, 6-71 mo), there was a mean change of -10.4 degrees in the segmental curvature (P < 0.001). The fused segment sagittal alignment also worsened (lordotic angles becoming straight or kyphotic and straight angles becoming kyphotic) in 44 patients (47%)(P < 0.001). However, serial studies in 34 patients (mean first and last follow-ups, 11.9 and 30.8 mo, respectively) did not demonstrate significant worsening of the kyphotic angle or the sagittal alignment over time (P = 0.9). Whole spine curvature worsened in 33 (35%) of the 93 patients (P < 0.001); serial studies did not reveal a significant change (P = 0.9). Patients improved in their functional status from a preoperative mean Nurick grade of 2.9 (range, 1-5) to a follow-up mean Nurick grade of 1.5 (range, 0-4) (P < 0.001). Patients with a kyphotic change in their whole spine curvature (n = 33) and those without such change (n = 60) had a similar functional outcome (mean change in Nurick grade, 1.5 and 1.4, respectively). CONCLUSION: Cervical spine curvature tended to undergo a kyphotic change at the fused segment in 47% of patients and a kyphotic change of the whole spine curvature in 35% of patients who underwent one- or two-level uninstrumented central corpectomy. This kyphotic change in the cervical spine, which stabilizes within 1 year after surgery, is not progressive, and it does not affect neurological outcome in these patients.     

The evolution of degenerative marrow (Modic) changes in the cervical spine in neck pain patients

Purpose

To evaluate the natural course of end plate marrow (Modic) changes (MC) in the cervical spine on MRI scans of patients with neck pain. A few longitudinal studies have assessed the development of MC over time in the lumbar spine but only two recent studies evaluated MC in the cervical spine in asymptomatic volunteers and those with whiplash. Thus, this study now reports on the natural course of MC in the cervical spine in symptomatic patients.

Methods

From the cervical MRI scans of 426 neck pain patients (mean age 61.2 years), 64 patients had follow-up MRI studies. The prevalence and types of MC were retrospectively assessed on the follow-up scans and compared to the original MRI findings.

Results

With an average of 2.5 years between the two MRI scans, the prevalence of MC type 1 (MC1) noted at baseline (7.4 % or 19 motion segments) slightly increased (8.2 % or 21 segments) but the prevalence of MC2 (14.5 % or 37 segments) increased considerably (22.3 % or 57 segments). In addition, 14 new MC1 segments and 8 new MC2 segments were noted. Twelve segments with MC1 at baseline converted to MC2 at follow-up. No conversion from MC2 to MC1 or reverting to a normal image was observed.

Conclusions

MC in the cervical spine are a dynamic phenomenon similar to the lumbar spine.     

Clinical and radiological follow-up of single-level Prestige LP cervical disc replacement

Objective

To evaluate the clinical outcomes and radiographic results of patients who underwent single-level cervical arthroplasty using the Prestige LP.

Method

Thirty-one patients with single-level cervical disc disease received the Prestige LP disc replacement from June 2008 to December 2009. The neck disability index (NDI), Japanese Orthopedic Association score (JOA) and visual analogue scale (VAS) were used to assessed clinical outcomes pre-operatively and post-operatively at 24 months. The overall cervical alignment (C2–7 Cobb angle), the functional segmental unit (FSU) curvature, the range of motion (ROM) of treated and adjacent levels were measured, and the evidence of heterotopic ossification (HO) was observed from static and dynamic radiographs.

Results

There was a statistically significant improvement in the NDI from 20.2 ± 7.5 to 6.4 ± 3.5 (P < 0.000), JOA from 12.8 ± 2.2 to 16.6 ± 0.6 (P < 0.000), the neck VAS score from 4.1 ± 2.5 to 1.4 ± 1.1 (P < 0.000), the arm VAS score from 4.6 ± 2.5 to 0.7 ± 1.1 (P < 0.000). The post-operative overall cervical alignment (9.3° ± 7.2°), ROM of treated level (7.6°) and adjacent level (upper level 9.4° ± 3.1°, lower level 9.1° ± 3.5°) are well maintained. The FSU were 0.2° ± 5.4° and 1.9° ± 5.5° at pre-operation and final follow-up with statistical significance (P = 0.011). Heterotopic ossification was evidenced in five operated segment (16 %).

Conclusions

The Prestige LP disc arthroplasty maintains favorable clinical outcomes, preserves the overall cervical alignment, FSU curvature, ROM of treated level and adjacent levels.     

What are the associative factors of adjacent segment degeneration after anterior cervical spine surgery? Comparative study between anterior cervical fusion and arthroplasty with 5-year follow-up MRI and CT

Purpose

It is well known that arthrodesis is associated with adjacent segment degeneration (ASD). However, previous studies were performed with simple radiography or CT. MRI is most sensitive in assessing the degenerative change of a disc, and this is the first study about ASD by radiography, CT and MRI. We sought to factors related to ASD at cervical spine by an MRI and CT, after anterior cervical spine surgery.

Materials and methods

This is a retrospective cross-sectional study of cervical disc herniation. Patients of cervical disc herniation with only radiculopathy were treated with either arthroplasty (22 patients) or ACDF with cage alone (21 patients). These patients were required to undergo MRI, CT and radiography preoperatively, as well as radiography follow-up for 3 months and 1 year, and we conducted a cross-sectional study by MRI, CT and radiography including clinical evaluations 5 years after. Clinical outcomes were assessed using VAS and NDI. The fusion rate and ASD rate, and radiologic parameters (cervical lordosis, operated segmental height, C2-7 ROM, operated segmental ROM, upper segmental ROM and lower segmental ROM) were measured.

Results

The study groups were demographically similar, and substantial improvements in VAS (for arm) and NDI (for neck) scores were noted, and there were no significant differences between groups. Fusion rates were 95.2 % in the fusion group and 4.5 % in the arthroplasty group. ASD rates of the fusion and arthroplasty groups were 42.9 and 50 %, respectively. Among the radiologic parameters, operated segmental height and operated segmental ROM significantly decreased, while the upper segmental ROM significantly increased in the fusion group. In a comparative study between patients with ASD and without ASD, the clinical results were found to be similar, although preexisting ASD and other segment degeneration were significantly higher in the ASD group. C2-7 ROM was significantly decreased in ASD group, and other radiologic parameters have no significant differences between groups.

Conclusion

The ASD rate of 46.5 % after ACDF or arthroplasty, and arthroplasty did not significantly lower the rate of ASD. ASD occurred in patients who had preexisting ASD and in patients who also had other segment degeneration. ASD may be associated with a natural history of cervical spondylosis rather than arthrodesis.     

Transvertebral anterior cervical foraminotomy: midterm outcomes of clinical and radiological assessments including the finite element method

Purpose

The aim of this study was to compare the clinical features, radiological changes, biomechanical effects, and efficacy in patients treated by transvertebral anterior foraminotomy. Preservation of segmental motion and avoidance of adjacent segment degeneration are theoretical advantages of transvertebral anterior foraminotomy. In practice, this procedure is minimally invasive and has shown good clinical results, especially in patients with unilateral cervical radiculopathy.

Method

We conducted a retrospective minimum 2-year follow-up study of the cervical spine of patients treated by transvertebral anterior foraminotomy at our institution. Radiological outcomes, which were estimated by measuring disc and functional spinal unit heights, and the angle and range of motion (ROM) from C2 to C7 of the functional spinal unit and adjacent segments were evaluated. Furthermore, a three-dimensional finite element method was used to biomechanically analyze the strength of the postoperative vertebral body.

Results

Between 2004 and 2009, 34 patients underwent surgery. The improvement rate was 94.2 %. The average flexion–extension ROM from C2 to C7 was 36.6 ± 16.6°. On plain radiographs, the disc height and ROM and height of the functional spinal unit in the operated segment were not significantly decreased relative to the preoperative levels. The finite element method also revealed that there was no difference in strength between the pre- and postvertebral bodies.

Conclusions

These results demonstrate that biomechanical stability was achieved. Transvertebral anterior cervical foraminotomy did not limit motion in the operated and adjacent segments and did not cause a significant decrease in disc and vertebral heights after surgery.     

Biomechanical effects of cervical arthroplasty with U-shaped disc implant on segmental range of motion and loading of surrounding soft tissue

Purpose

Various design concepts have been adopted in cervical disc prostheses, including sliding articulation and standalone configuration. This study aimed to evaluate the biomechanical effects of the standalone U-shaped configuration on the cervical spine.

Methods

Based on an intact finite element model of C3–C7, a standalone U-shaped implant (DCI) was installed at C5–C6 and compared with a sliding articulation design (Prodisc-C) and an anterior fusion system. The range of motion (ROM), adjacent intradiscal pressure (IDP) and capsular ligament strain were calculated under different spinal motions.

Results

Compared to the intact configuration, the ROM at C5–C6 was reduced by 90 % after fusion, but increased by 70 % in the Prodisc-C model, while the maximum percentage change in the DCI model was 30 % decrease. At the adjacent segments, up to 32 % increase in ROM happened after fusion, while up to 34 % decrease occurred in Prodisc-C model and 17 % decrease in DCI model. The IDP increased by 11.6 % after fusion, but decreased by 5.6 and 6.3 % in the DCI and Prodisc-C model, respectively. The capsular ligament strain increased by 147 % in Prodisc-C and by 13 % in the DCI model. The DCI implant exhibited a high stress distribution.

Conclusions

Spinal fusion resulted in compensatory increase of ROM at the adjacent sites, thereby elevating the IDP. Prodisc-C resulted in hyper-mobility at the operative site that led to an increase of ligament force and strain. The U-shaped implant could maintain the spinal kinematics and impose minimum influence on the adjacent soft tissues, despite the standalone configuration encountering the disadvantages of high stress distribution.     

Cervical reconstruction techniques. After adequate selection of the patient report of a series of 34 patients treated with winged expandable cages

After single or multilevel cervical corpectomy for the treatment of different diseases, many surgical options have been proposed over the years. As a single device, a winged expandable titanium cage (WETC) has been developed. We report the use of this device and our clinical results at 24 months of follow-up in a prospective series of 34 patients who underwent single or multilevel corpectomy for the treatment of cervical spondylosis. Thirty-four consecutive patients underwent single or multilevel cervical corpectomy followed by the insertion of a WETC for the treatment of cervical spondylosis at Department of Neurology and Psychiatry “Sapienza” University of Rome, Italy, from May 2011 to May 2013. Patients affected by cervical spondylosis with cervical lordosis >0° were included. Patients affected by cervical lordosis <0°, osteoporosis, or other cervical diseases were excluded. The mean postsurgical Nurick’s grade was significantly lower than the mean presurgical Nurick’s grade (mean = 0.98 for postsurgical Nurick’s grade and mean = 2.42 for presurgical Nurick’s grade). Four patients (11.7 %) presented subsidence respectively of 1, 2, 2, and 3 mm at 24 months of radiological follow-up. Postoperative complications occurred in five patients (14.7 %). Our case series at 24 months of follow-up demonstrates that the use of a WETC obtains good clinical results after single or multiple corpectomy in patients not affected by osteoporosis who do not require cervical lordosis correction. During the insertion of the device, an adequate preparation of the end plates is suggested and their over distraction should be avoided.