A Hollow Cylindrical PMMA Strut for Cervical Spine Reconstruction After Cervical Multilevel Corpectomy

Cervical Spine Reconstruction with Chest Tube Technique After Metastasis Resection: A Single-Center Experience

BACKGROUND

The silastic tube technique, in which a chest tube is placed into the vertebral body defect and impregnated with polymethyl methacrylate, showed good results in patients with lumbar and thoracic neoplastic diseases. There has been only 1 study about the effectiveness and safety of this technique in patients with cervical metastases. We aimed to report our experience in using this technique to reconstruct the spine after corpectomy for cervical metastasis.

METHODS

All patients with cervical spinal metastasis who underwent surgical treatment using a chest tube impregnated with polymethyl methacrylate in conjunction with anterior cervical plate stabilization were retrospectively recruited. Demographics, tumor histology, revised Tokuhashi score, preoperative and postoperative American Spinal Injury Association score, preoperative and postoperative ambulatory status, perioperative complications, and survival time were collected.

RESULTS

This study included 16 patients. The most common primary tumor site was the lung (6 patients; 37.5%). The mean (SD) survival time was 408 (401) days (range, 1-2797 days), and the median survival time was 72 days (95% confidence interval 28-116 days). Four patients (25%) died within 30 postoperative days. There was no surgical site infection or instrument failure after the surgery. Five patients (31.2%) lived >180 days, and 3 patients (18.8%) lived >360 days. One patient (6.2%) was still alive at the end of the study.

CONCLUSIONS

The silastic tube technique in conjunction with anterior cervical plate stabilization might be safe, effective, and cost-effective for patients with cervical spine metastasis.

Can Self-Locking Cages Offer the Same Clinical Outcomes as Anterior Cage-with-Plate Fixation for 3-Level Anterior Cervical Discectomy and Fusion (ACDF) in Mid-Term Follow-Up?

Background

Self-locking stand-alone cages (MC+) and cage-with-pate fixation system are 2 different surgical methods used in anterior cervical discectomy and fusion (ACDF), but few systematic comparative studies comparing the 2 methods in treating multilevel cervical spondylotic myelopathy (MCSM) have been published.

Material/Methods

Sixty-two patients with MCSM who underwent multilevel ACDF were enrolled and completed at least a 3-year postoperative follow-up. The operative time, intra-operative blood loss, and clinical and radiological results were compared between the MC+ self-locking cages group and the cage-with-plate fixation group. Clinical parameters, including VAS for neck pain, Japanese Orthopedic Association (JOA) score, and neck disabled index (NDI), were evaluated. Surgical results according to Odom’s criteria and postoperative dysphagia status, C5 nerve root palsy, and loosening of the instrumentation were recorded. Postoperative radiological results, including fusion rates, fusion segmental Cobb’s angle (FSC), cervical lordosis, fusion segmental height (FSH), cage subsidence, and adjacent segment degeneration, were assessed.

Results

The VAS score, JOA score, and NDI score were significantly improved in both groups. However, the patients in the cage-with-plate group were more likely to have neck pain at the last follow-up. The cervical lordosis, FSC, and FSH showed significant correction immediately after surgery. The loss of the cervical lordosis and FSH were higher in the MC+ group.

Conclusions

We found that use of MC+ cages is safe and effective in treating MCSM, but for patients who require strong postoperative stabilization and maintaining the cervical alignment better, the cage-with-plate fixation may best.

Developments of nano-TiO2 incorporated hydroxyapatite/PEEK composite strut for cervical reconstruction and interbody fusion after corpectomy with anterior plate fixation

The technique of anterior cervical corpectomy and fusion (ACCF) for strut grafting has become a widespread and actively applied for many cervical complaints including cervical degeneration of the intervertebral disks, cervical trauma, cancer, rheumatoid arthritis and multilevel cervical spondylotic diseases. To avoid the complications of the old techniques, the construct stability and long anterior screw-plate designs of the bone strut have been improved by using effective biomaterials. The nanostructured hydroxyapatite (HAp) incorporated with biocompatible polymer matrixes is an effective biomedical material and creating a functional properties applied for different tissue replacements such as dental, hips, knees, tendon and ligaments and tissue repair for maxillofacial reconstruction, stabilization of the jaw bone and spinal fusion. In the present investigation, we have successfully designed cylindrical nano titanium dioxide (n-TiO₂) interbody fusion with anterior plate fixation. The n-TiO₂ incorporated HAp/ Polyetheretherketone (PEEK) nanocomposite strut has a superior mechanical properties and larger contact area with high fusion rates as compared with the HAp/PEEK strut in the absence of n-TiO₂ nanoparticles. It is highly able to provide appropriate strength and biological activity similar to the conventional titanium cage and also mainly it has been minimizes subsidence value. The synthesized novel material of n-TiO2 incorporated HAp/PEEK nanocomposite strut is scientifically given effective outcomes for fusion and reconstruction of the ACCF.

Anterior decompression and hybrid reconstruction with titanium mesh cage plus plate and self-locking stand-alone cage for the treatment of three-level cervical spondylotic myelopathy

It has been reported that anterior cervical decompression has good clinical outcomes for the treatment of adjacent three-level cervical spondylotic myelopathy (CSM). However, the application of a long plate in the anterior cervical spine poses substantial risks of soft tissue damage. In this retrospective study, we aimed to analyze the clinical and radiological results of the hybrid construction with titanium mesh cage (TMC) plus plate and self-locking stand-alone cage for treatment of adjacent three-level CSM. A total of 28 consecutive patients with adjacent three-level CSM were treated by anterior decompression and hybrid reconstruction with TMC plus plate and self-locking stand-alone cage. Clinical outcomes, complications, fusion rate and time, cage subsidence and spinal curvature were assessed. The mean follow-up period was 22.8months. The average operative time was 103±18.5min, and the average blood loss was 115±13.3mL. The JOA score and degree of spinal curvature were significantly increased at the final follow-up compared with preoperatively (P<0.05). Twenty-seven cases finally achieved a solid fusion, and the average time to achieve a solid fusion was 6.2months. Postoperative complications included one case of cerebrospinal fluid leakage (3.57%), one case of temporary sore throat (3.57%) and two cases of TMC subsidence (7.1%). No dysphagia and hoarseness were observed. Anterior decompression and hybrid reconstruction with TMC plus plate and self-locking stand-alone cage could be used safely and effectively for the treatment of adjacent three-level CSM. It could effectively restore cervical lordosis, reduce the complications related to long plate fixation, and lead to satisfactory outcomes.

Long-term results of anterior cervical corpectomy and fusion with nano-hydroxyapatite/polyamide 66 strut for cervical spondylotic myelopathy

To assess the long-term clinical and radiographic outcomes of anterior cervical corpectomy and fusion (ACCF) with a neotype nano-hydroxyapatite/polyamide 66 (n-HA/PA66) strut in the treatment of cervical spondylotic myelopathy (CSM). Fifty patients with CSM who underwent 1- or 2-level ACCF with n-HA/PA66 struts were retrospectively investigated. With a mean follow-up of 79.6 months, the overall mean JOA score, VAS and cervical alignment were improved significantly. At last follow-up, the fusion rate was 98%, and the subsidence rate of the n-HA/PA66 strut was 8%. The "radiolucent gap" at the interface between the n-HA/PA66 strut and the vertebra was further noted to evaluate the osteoconductivity and osseointegration of the strut, and the incidence of it was 62% at the last follow-up. Three patients suffered symptomatic adjacent segment degeneration (ASD). No significant difference was detected in the outcomes between 1- and 2-level corpectomy at follow-ups. In conclusion, the satisfactory outcomes in this study indicated that the n-HA/PA66 strut was an effective graft for cervical reconstruction. Moreover, the osteoconductivity and osseointegration of the strut is still need to be optimized for future clinical application owing to the notably presence of "radiolucent gap" in present study.

360-degree cervical spinal arthrodesis for treatment of pediatric cervical spinal tuberculosis with kyphosis

BACKGROUND

There is limited evidence to guide treatment for pediatric cervical spinal tuberculosis with kyphosis (PCSTK). This study retrospectively evaluates the safety, feasibility and efficacy of 360-degree arthrodesis combined with anterior debridement and decompression for treating PCSTK, while simultaneously emphasizing the role of posterior fixation for the correction and maintenance of the kyphosis angle.

METHODS

From May 2006 to December 2012, a total of 12 children with PCSTK underwent 360-degree cervical spinal arthrodesis followed by debridement of focus and decompression of the spinal cord. Data on the angle of kyphosis correction, visual analogue scale scores of pain, the American Spinal Injury Association scoring system of nerve function scores, erythrocyte sedimentation rate (ESR) and body weight were collected at certain periods. Clinical efficacy was evaluated by statistical analysis based on collected data.

RESULTS

Average follow-up period was 34.3 ± 8.6 months. No postoperative complications related to the instrumentation occurred, and neurologic function improved in various degrees. Preoperative kyphosis angle was 41.4 ± 5.2°, and significantly decreased to -4.9 ± 4.9° after surgery. The correction of kyphosis and loss of correction were 47.1 ± 4.9° and 0.6 ± 1.4°, respectively. Average pretreatment ESR was 49.8 ± 13.2 mm/h, which normalized (8.5 ± 0.6 mm/h) within three months in all patients. Average preoperative visual analogue scale was 6.6 ± 1.6, which decreased to 2.3 ± 1.4 postoperatively and 0.3 ± 0.5 during the final follow-up. Mean preoperative body weight was 25.9 ± 5.1 kg, and body weight was 33.5 ± 4.8 kg at the third month of post-operation. Bone healing was achieved in all patients after a mean period of 5.4 months.

CONCLUSIONS

360-degree arthrodesis combined with anterior debridement and decompression is a safe and effective method for the treatment of PCSTK. For the correction and maintenance of the kyphosis angle, additional posterior fixation is recommended.

Vertebral body replacement with PEEK-cages after anterior corpectomy in multilevel cervical spinal stenosis: a clinical and radiological evaluation

INTRODUCTION

A growing number of industrially manufactured implants have been developed in the last years for vertebral replacement in anterior cervical corpectomy and fusion (ACCF). Polyetheretherketone (PEEK)-cages are used in many centers, but outcome reports are scarce. This study assesses the clinical and radiological outcome after one- or two-level ACCF by the use of a PEEK-cage augmented by a plate-screw osteosynthesis.

METHODS

A total of 21 patients received one-level (18 patients) or two-level (3 patients) ACCF by a PEEK-cage and plate-screw osteosynthesis for multilevel degenerative stenosis. The Visual Analogue Scale, Nurick Score, Neck Disability Index and European Myelopathy Score were used for clinical assessment. Radiological outcome-osseous fusion and loss of height-was evaluated by CT.

RESULTS

The mean follow-up was 28 ± 12 months. In 19 patients, bony fusion was achieved after the primary operation. Graft failure that required surgical revision occurred in two patients. In these patients, osseous fusion was achieved after the second operation. Myelopathy improved significantly. The loss of height was 2.2 ± 2.3 and 5.3 ± 2.1 mm after one- and two-level ACCF, respectively.

CONCLUSION

Anterior corpectomy and fusion by a PEEK-cage and plate-screw osteosynthesis resulted in clinical improvement in all patients. Bony fusion was achieved in all patients in the long run. PEEK cages are allegedly less rigid than other xenografts. Similar to those, however, their use bears the risk of early cage-dislocation and subsidence. A comparison of industrial xenografts and autologous bone implants is required to challenge the different fusion techniques.

Outcome of single level anterior cervical discectomy and fusion using nano-hydroxyapatite/polyamide-66 cage

BACKGROUND

Cages have been widely used for the anterior reconstruction and fusion of cervical spine. Nonmetal cages have become popular due to prominent stress shielding and high rate of subsidence of metallic cages. This study aims to assess fusion with n-HA/PA66 cage following one level anterior cervical discectomy.

MATERIALS AND METHODS

Forty seven consecutive patients with radiculopathy or myelopathy underwent single level ACDF using n-HA/PA66 cage. We measured the segmental lordosis and intervertebral disc height on preoperative radiographs and then calculated the loss of segmental lordosis correction and cage subsidence over followup. Fusion status was evaluated on CT scans. Odom criteria, Japanese Orthopedic Association (JOA) and Visual Analog Pain Scales (VAS) scores were used to assess the clinical results. Statistically quantitative data were analyzed while Categorical data by χ(2) test.

RESULTS

Mean correction of segmental lordosis from surgery was 6.9 ± 3.0° with a mean loss of correction of 1.7 ± 1.9°. Mean cage subsidence was 1.2 ± 0.6 mm and the rate of cage subsidence (>2 mm) was 2%. The rate of fusion success was 100%. No significant difference was found on clinical or radiographic outcomes between the patients (n=27) who were fused by n-HA/PA66 cage with pure local bone and the ones (n=20) with hybrid bone (local bone associating with bone from iliac crest).

CONCLUSIONS

The n-HA/PA66 cage is a satisfactory reconstructing implant after anterior cervical discectomy, which can effectively promote bone graft fusion and prevent cage subsidence.

Comparison of anterior cervical fusion by titanium mesh cage versus nano-hydroxyapatite/polyamide cage following single-level corpectomy

PURPOSE

The titanium mesh cage (TMC) is a typical metal cage device which has been widely used in cervical reconstruction for decades. Nano-hydroxyapatite/polyamide-66 (n-HA/PA66) cage is a novel biomimetic non-metal cage device growing in popularity in many medical centres in recent years. There has been no comparison of the efficacy between these two anterior reconstructing cages. The purpose of this study was to compare the radiographic and clinical outcomes of these two different devices.

METHODS

Sixty-seven eligible patients with single-level ACCF using TMC or n-HA/PA66 cage for cervical degenerative diseases, with four-year minimum follow-up, were included in this prospective non-randomised comparative study. Their radiographic (cage subsidence, fusion status, segmental sagittal alignment [SSA]) and clinical (VAS and JOA scales) data before surgery and at each follow-up was recorded completely.

RESULTS

The fusion rate of the n-HA/PA66 group was higher than TMC at one year after surgery (94% vs. 84%) though their finial fusion rates were similar (97% vs. 94%). Finial n-HA/PA66 cage subsidence was 1.5 mm with 6% of severe subsidence over three millimetres, which was significantly lower than the respective 2.9 mm and 22% of TMC (P < 0.0001). Lastly, SSA, VAS and JOA in TMC group were worse than in the n-HA/PA66 group (P = 0.235, 0.034 and 0.007, respectively).

CONCLUSIONS

The n-HA/PA66 cage is associated with earlier radiographic fusion, less subsidence and better clinical results than TMC within four years after one-level ACCF. With the added benefit of radiolucency, the n-HA/PA66 cage may be superior to TMC in anterior cervical construction.

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.

Publication patterns of comparative effectiveness research in spine neurosurgery

OBJECT

The purpose of this study was to investigate publication patterns for comparative effectiveness research (CER) on spine neurosurgery.

METHODS

The authors searched the PubMed database for the period 1980-2012 using the key words "cost analysis," "utility analysis," "cost-utility," "outcomes research," "practical clinical research," "comparator trial," and "comparative effectiveness research," linked with "effectiveness" and "spine neurosurgery."

RESULTS

From 1980 through April 9, 2012, neurosurgery CER publications accounted for 1.38% of worldwide CER publications (8657 of 626,330 articles). Spine neurosurgery CER accounted for only 0.02%, with 132 articles. The journal with the greatest number of publications on spine neurosurgery CER was Spine, followed by the Journal of Neurosurgery: Spine. The average annual publication rate for spine neurosurgery CER during this period was 4 articles (132 articles in 33 years), with 68 (51.52%) of the 132 articles being published within the past 5 years and a rising trend beginning in 2008. The top 3 contributing countries were the US, Turkey, and Japan, with 68, 8, and 7 articles, respectively. Only 8 regular articles (6.06%) focused on cost analysis.

CONCLUSIONS

There is a paucity of publications using CER methodology in spine neurosurgery. Few articles address the issue of cost analysis. The promotion of continuing medical education in CER methodology is warranted. Further investigations to address cost analysis in comparative effectiveness studies of spine neurosurgery are crucial to expand the application of CER in public health.

A simple method for making a hollow cylindrical polymethylmethacrylate strut for cervical spinal reconstruction

Object

The purpose of this study was to introduce a method for making a hollow cylindrical polymethylmethacrylate (PMMA) strut for perioperative anterior spinal reconstruction after discectomy and/or corpectomy.

Methods

For use after anterior cervical discectomy or corpectomy, the authors created a hollow cylindrical PMMA strut using 10- and 3-ml disposable plastic syringes filled with PMMA containing 10% BaSO4 for anterior spinal reconstruction.

Results

With this method, the authors were able to make a PMMA strut that was approximately 50 mm in length with a 14-mm outer diameter and a 10-mm inner diameter. The PMMA strut could easily be cut with a saw to any desired length and molded with a cutting bur. The PMMA strut was used as a substitute for the cortical bone and was filled with bone graft for cervical spinal reconstruction after discectomy and/or corpectomy. The whole process of making the PMMA strut can be completed within 30 minutes, and it reduces costs by at least $1000 US (in 1-level discectomy), making the procedure cost effective.

Conclusions

It is simple to make a hollow cylindrical PMMA strut with plastic syringes during a discectomy and/or corpectomy. The strut can provide adequate support at less cost than other methods. The hollow cylindrical strut is also of suitable size and length for anterior spinal reconstruction. It serves as an alternative for patients who cannot afford the expense of similar instruments or who cannot or do not want to take the risk of a human graft for anterior spinal reconstruction.