[Development and in vivo biomechanics of goat mobile artificial lumbar spine complex]

OBJECTIVE

Mobile artificial lumbar complex (MALC) which suitable for reconstruction after subtotal lumbar resection in goats was developed,and to test stability of the complex and postoperative lumbar segmental motor function.

METHODS

Eighteen male boer goats aged from 1 to 2 years old (weighted from 35 to 45 kg) were selected and divided into control group,fusion group and non-fusion group,with 6 goats in each group. According to preoperative CT scans and MRI examinations of lumbar,the goat MALC was designed and performed by 3D printed for non-fusion group. Operation was performed on three groups respectively,and only vertebral body and disc were exposed in control group. In fusion group,L4 part of vertebral body and the upper and lower complete disc tissues were removed,and the lumbar spine bone plate fixation was performed with titanium mesh bone grafting. In non-fusion group,vertebral body and disc were removed in the same way,and MALC was implanted. AP and lateral X-rays of lumbar vertebrae in goat were taken at 6 months after surgery,in order to understand whether the plant was dislocated,displaced and fractured. Biomechanical tests were performed on the specimens by mechanical instrument to measure range of motion (ROM) of L2,3,L3,4,L4,5 intervertebral space and the overall ROM of L2-5 lumbar vertebrae.

RESULTS

MALC of lumbar vertebra was designed by 3D printing,and its component artificial vertebrae and upper and lower artificial end plates were manufactured. The semi-spherical structure was fabricated by precision lathe using high-crosslinked polyethylene material,and the prosthesis was assembled. Postoperative AP and lateral X-rays of lumbar vertebra at 6 months showed the implant position of implant and MALC were good without displacement and dislocation. In vitro biomechanical test of lumbar vertebrae specimens:(1) There were no statistical significance in ROM of lumbar intervertebral space flexion and extension,lateral flexion and rotation on L3,4 and L4,5,between non-fusion group and control group (P>0.05),while ROM of fusion group was significantly reduced compared with the other two groups (P<0.05). There were no significant difference in ROM of L2,3 intervertebral flexion and extension,lateral flexion and rotation between non-fusion group and control group (P>0.05),while fusion group was significantly increased compared with the other two groups (P<0.001). (2) There was no significant difference in overall lumbar ROM of L2-5 (P> 0.05).

CONCLUSION

The individual MALC could restore intervertebral height of lumbar vertebra while maintaining the stability of lumbar vertebra and re-establishing motor function of lumbar space.

Risk Factors of Nonfusion after Anterior Cervical Decompression and Fusion in the Early Postoperative Period: A Retrospective Study

OBJECTIVE

Although high fusion rates have been reported for anterior cervical decompression and fusion (ACDF) in the medium and long term, the risk of nonfusion in the early period after ACDF remains substantial. This study investigates early risk factors for cage nonfusion in patients undergoing single- or multi-level ACDF.

METHODS

This was a retrospective study. From August 2020 to December 2021, 107 patients with ACDF, including 197 segments, were enrolled, with a follow-up of 3 months. Among the 197 segments, 155 were diagnosed with nonfusion (Nonfusion group), and 42 were diagnosed with fusion (Fusion group) in the early period after ACDF. We assessed the significance of the patient-specific factors, radiographic indicators, serum factors, and clinical outcomes. The Wilcoxon rank sum test, t-tests, analysis of variance, and stepwise multivariate logistic regression were used for statistical analysis.

RESULTS

Univariate analysis showed that smoking, insufficient improvement in the C2-7 Cobb angle (p = 0.024) and the functional spinal unit Cobb angle (p = 0.022) between preoperative and postoperative stages and lower serum calcium (fusion: 2.34 ± 0.12 mmol/L; nonfusion: 2.28 ± 0.17 mmol/L, p = 0.003) β-carboxyterminal telopeptide end of type 1 collagen (β-CTX) (fusion: 0.51 [0.38, 0.71]; nonfusion: 0.43 [0.31, 0.57], p = 0.008), and N-terminal fragment of osteocalcin (N-MID-BGP) (fusion: 18.30 [12.15, 22.60]; nonfusion: 14.45 [11.65, 18.60], p = 0.023) are risk factors for nonfusion in the early period after ACDF. Stepwise logistic regression analysis revealed that poor C2-7 Cobb angle improvement (odds ratio [OR], 1.107 [1.019-1.204], p = 0.017) and lower serum calcium (OR, 3.700 [1.138-12.032], p = 0.030) are risk factors.

CONCLUSIONS

Patients with successful fusion after ACDF had higher preoperative serum calcium and improved C2-7 Cobb angle than nonfusion patients at 3 months. These findings suggest that serum calcium could be used to identify patients at risk of nonfusion following ACDF and that correcting the C2-7 Cobb angle during surgery could potentially increase fusion in the early period after ACDF.

Are We Looking at a Paradigm Shift in the Management of Adolescent Idiopathic Scoliosis? Comprehensive Retrospective Analysis of 75 Patients of Nonfusion Anterior Scoliosis Correction with 2-5-Year Follow-up: A Single Center Experience

Study Design

Retrospective cohort study.

Purpose

This study aimed to evaluate the clinical and radiological outcomes of nonfusion anterior scoliosis correction (NFASC) in patients with idiopathic scoliosis and comprehensively analyze its principles.

Overview of Literature

NFASC is a novel revolutionary motion-preserving surgery for idiopathic scoliosis. However, clinical data related to this procedure remain scarce, with no conclusive guidelines regarding case indications, proper technique, and possible complications.

Methods

This study included patients with adolescent idiopathic scoliosis (AIS) who were treated with NFASC for a structural major curve (Cobb angle, 40°-80°) with more than 50% flexibility on dynamic X-rays. The mean follow-up was 26±12.2 months (range, 12- 60 months). Clinical and radiological data such as skeletal maturity, curve type, Cobb angle, surgery details, and Scoliosis Research Society-22 revised (SRS-22r) questionnaire were collected. Statistically significant trends were examined by post hoc analysis following repeated measures analysis of variance test.

Results

A total of 75 patients (70 females, five males) were included, with a mean age of 14.96±2.69 years. The mean Risser and Sanders scores were 4.22±0.7 and 7.15±0.74, respectively. The mean main thoracic Cobb angles at the first and second follow-up (17.2°±5.36° and 16.92°±5.06°, respectively) were significantly lower than the preoperative Cobb angles (52.11°±7.74°) (p <0.05). Similarly, the mean thoracolumbar/lumbar Cobb angle significantly improved from the preoperative period (51.45°±11.26°) to the first follow-up (13.48°±5.11°) and last follow-up (14.24°±4.85°) (p <0.05). The mean preoperative and postoperative SRS-22r scores were 78.0±3.2 and 92.5±3.1, respectively (p <0.05). None of the patients had any complications until the most recent follow-up.

Conclusions

NFASC offers promising curve correction and curve progression stabilization in patients with AIS, with a low risk for complications and preservation of spinal mobility and sagittal parameters. Thus, it proves to be a favorable alternative to fusion modality.

Long-Term Clinical and Radiological Evaluation of Low-Grade Lumbar Spondylolisthesis Stabilization with Rigid Percutaneous Pedicle Screws

The armamentarium of surgical treatment options for lumbar spondylolisthesis (LS) includes decompression alone, stabilization with interlaminar devices, or instrumented fusion, through open or minimally invasive approaches. Despite its safe profuse use in distinctive lumbar spine disorders, using percutaneous pedicle screws (PPSs) alone to stabilize LS has never been described before. We performed a retrospective study of prospectively collected data, enrolling 24 patients with LS and scrutinizing clinical and radiological outcomes. A statistically significant decrease in visual analog scale (VAS) scores (p < 0.001) and Oswestry Disability Index (ODI) scores (p < 0.001) was observed, as was a reduction in the intake of acetaminophen after surgery (p = 0.022). In the long-term, PPS effectively reduced the index-level range of motion (p < 0.001), reduced preoperative slippage (p = 0.03), and maintained foraminal height, thus accounting for the positive clinical outcomes. It induced a significant segmental kyphotic effect (p < 0.001) that was compensated for by a favorable increase in the pelvic incidence minus lumbar lordosis (PI-LL) index (0.028).

Comparison Between Fusion and Non-Fusion Surgery for Lumbar Spinal Stenosis: A Meta-analysis

INTRODUCTION

A large number of studies have shown that, for severe lumbar spinal stenosis, decompression surgery can often obtain better results than non-surgical treatment. However, whether the lumbar spine is fixed after decompression is still controversial. The results of biomechanical studies indicate that there is a correlation between the range of decompression and postoperative spinal instability.

METHODS

The multiple databases like Pubmed, Embase, Cochrane databases and China National Knowledge database were used to search for the relevant studies, and full-text articles involved in the evaluation of fusion and nonfusion surgery for lumbar spinal stenosis. Review Manager 5.2 was adopted to estimate the effects of the results among selected articles. Forest plots, sensitivity analysis and bias analysis for the articles included were also conducted.

RESULTS

A total of nine relevant studies were eventually satisfied the included criteria. There were significant differences in length of stay [mean difference (MD) = 3.04, 95% CI (2.00, 4.08), P < 0.000]1), but there were no differences in Oswestry Disability Index (ODI score) [MD = - 1.14, 95% CI (- 2.92, 0.63), P = 0.21; I² = 87%] and complications [RR = 1 with 95% CI (0.69, 1.46), P value of overall effect was 0.98]. The study was robust and limited publication bias was observed in this study.

CONCLUSION

Our research supported that fusion and nonfusion surgeries had no differences in clinical effects and complications for lumbar spinal stenosis, while fusion surgery involved a longer length of stay than nonfusion surgery.

Chlorhexidine Showers are Associated With a Reduction in Surgical Site Infection Following Spine Surgery: An Analysis of 4266 Consecutive Surgeries

BACKGROUND

Surgical site infection (SSI) is a common complication following spinal surgery. Prevention is critical to maintaining safe patient care and reducing additional costs associated with treatment.

OBJECTIVE

To determine the efficacy of preoperative chlorhexidine (CHG) showers on SSI rates following fusion and nonfusion spine surgery.

METHODS

A mandatory preoperative CHG shower protocol was implemented at our institution in November 2013. A cohort comparison of 4266 consecutive patients assessed differences in SSI rates for the pre- and postimplementation periods. Subgroup analysis was performed on the type of spinal surgery (eg, fusion vs nonfusion). Data represent all spine surgeries performed between April 2012 and April 2016.

RESULTS

The overall mean SSI rate was 0.4%. There was no significant difference between the pre- (0.7%) and postimplementation periods (0.2%; P = .08). Subgroup analysis stratified by procedure type showed that the SSI rate for the nonfusion patients was significantly lower in the post- (0.1%) than the preimplementation group (0.7%; P = .02). There was no significant difference between SSI rates for the pre- (0.8%) and postimplementation groups (0.3%) for the fusion cohort (P = .21). In multivariate analysis, the implementation of preoperative CHG showers were associated with significantly decreased odds of SSI (odds ratio = 0.15, 95% confidence interval [0.03-0.55], P < .01).

CONCLUSION

This is the largest study investigating the efficacy of preoperative CHG showers on SSI following spinal surgery. In adjusted multivariate analysis, CHG showering was associated with a significant decrease in SSI following spinal surgery.

Risk Factors for Instrumentation Failure After Total En Bloc Spondylectomy of Thoracic and Lumbar Spine Tumors Using Titanium Mesh Cage for Anterior Reconstruction

OBJECTIVE

The present study investigated the risk factors for instrumentation failure (IF) after total en bloc spondylectomy (TES) of thoracic and lumbar spine tumors using a titanium mesh cage (TMC) for anterior reconstruction.

METHODS

The data from patients who had undergone TES for thoracic and lumbar spine tumors in our institution were retrospectively reviewed. Anterior reconstruction was performed using a TMC filled with morcelized allograft or morcelized autograft. Posterior reconstruction was performed using pedicle fixation. Survival analysis from TES to IF was conducted. The Kaplan-Meier method was used for univariate analysis. Factors of statistical significance were included in the multivariate analysis using Cox regression analysis.

RESULTS

A total of 30 patients (20 men and 10 women), with a mean age of 37.1 ± 14.3 years (range, 14-65 years) were included. The mean follow-up period was 41.8 ± 21.3 months (range, 13-120 months). Bone fusion was achieved in 23 patients (76.7%). IF occurred in 8 patients. The mean interval from TES to the first IF was 31.8 ± 15.1 months (range, 13-64 months). On univariable analysis, a body mass index >28 kg/m², perioperative radiotherapy, and the TMC in an oblique position were associated with IF. On multivariable analysis, these 3 factors were entered into the Cox regression model and were also significant.

CONCLUSIONS

The use of TES can achieve durable oncological control. However, IF, a not uncommon late complication that leads to reoperation, should be a cause for concern. We found perioperative radiotherapy, a TMC in an oblique position, and a body mass index >28 kg/m² were significant predictive factors for IF.

Severe Pott's Kyphosis in a 19-Month-Old Child: Case Report and Review of Literature

BACKGROUND

Spinal osseous tuberculosis, or Pott's spine, although very common in endemic countries, has a lower incidence in very young children. However, the infection has the propensity to cause greater vertebral destruction in this age group, leading to severe structural kyphotic deformity and associated neurologic deficits. We report the case of a 19-month-old child with severe tubercular kyphotic deformity of the upper thoracic spine managed with posterior vertebral column resection (VCR) and nonfusion posterior pedicle screw instrumentation.

CASE DESCRIPTION

This 19-month-old boy presented with 1-month history of spontaneous-onset, progressive, painful rigid kyphotic deformity of the upper back associated with spastic paraparesis with bowel and bladder incontinence. Magnetic resonance imaging showed severe destruction of bodies of D4-D7 vertebrae with cord edema and draping of the spinal cord over the internal gibbus at D4-D7. Surgery was performed with a restricted anterior fusion via single-stage posterior VCR at D4-D7 with nonfusion pedicle screw instrumentation from D1 to D9, with subsequent extension of instrumentation to D10 after 4 months.

CONCLUSIONS

Multilevel posterior VCR with a restricted fusion and nonfusion pedicle screw instrumentation beyond the resection site can be safely done in young children (age <3 years) requiring rigid tubercular kyphotic deformity correction. However, these patients require regular follow-up and may need multiple surgeries.

A Severe Case of Hirayama Disease Successfully Treated by Posterior Cervical Fixation without Decompression and Fusion

BACKGROUND

Hirayama disease (HD) is a rare disease traditionally treated with nonsurgical procedures. Surgical treatment, which is performed by decompression and/or fusion of the cervical spine, is generally considered for rapidly progressive or advanced cases, and the choice of surgical technique is debatable. We describe the first severe case of HD that was successfully treated by posterior lateral mass screw fixation without decompression or fusion.

CASE DESCRIPTION

The patient was a 17-year-old adolescent boy who presented with progressive symptoms bilaterally with an unsatisfactory history of conservative treatment. We performed posterior lateral mass screw fixation without decompression or fusion and removed the internal fixation after 4 years of follow-up. Symptom remission and imaging performance improvement were achieved, and the stability and range of motion of the cervical spine were maintained.

CONCLUSIONS

Nondecompression and nonfusion surgery was successful and achieved satisfactory results in this case; therefore, it serves as a promising candidate for the surgical treatment of HD.

Nonfusion Intracorporeal Enhancement System for the Treatment of Osteoporotic Vertebral Compression Fractures-Preliminary Clinical Result of a Novel Technique

OBJECTIVE

This study sought to determine whether implantation of a newly designed nonfusion intracorporeal enhancement (NICE) system is an effective and safe way to treat osteoporotic vertebral compression fracture (OVCF).

METHODS

Thirteen patients with OVCF (10 women, 3 men; mean age 69 years, T11-L4) were included. From June 2014 to June 2016, all patients were treated with the NICE system. The clinical and radiologic results were evaluated preoperatively, postoperatively, and at 24 months follow-up based on the visual analog scale and the Oswestry Disability Index, radiography, magnetic resonance imaging, and computed tomography (height of fractured body and kyphosis Cobb angle).

RESULTS

There was a significant improvement in pain intensity (visual analog scale score decreased from 8.3 preoperatively to 2.2 postoperatively, and decreased to 1.5 twenty-four months postoperatively). Also, a significant reduction was observed in that the mean Oswestry Disability Index decreased from 71.9% preoperatively to 17.6% after 24 months. The mean Cobb angle had a significant improvement, which decreased from 6.6° preoperatively to 1.3° postoperatively and then decreased to 1.2° after 24 months. Height of fractured body improved significantly from 66.4% to 86.5% and slightly decreased to 82.4% after 24 months. No specific complications were identified to be associated with this technique.

CONCLUSIONS

With a low complication rate, the clinical midterm results are satisfactory. The treatment of symptomatic OVCF with the NICE system is a safe and effective procedure.

Is It Feasible to Treat Odontoid Fractures via Primary Posterior Reduction and Fixation without Fusion?

OBJECTIVE

To evaluate results and feasibility of primary posterior reduction and fixation without fusion using C1-C2 screw-rod system for odontoid fractures.

METHODS

This study comprised a consecutive series of 46 patients with odontoid fractures. Posterior reduction and fixation without fusion using the C1-C2 screw-rod system was performed, and instrumentation was not removed. Radiologic outcomes were assessed on follow-up computed tomography or plain radiographs. Visual analog scale of neck pain, American Spinal Injury Association impairment scale, patient satisfaction, neck disability index, and range of motion of flexion extension and rotation of the cervical spine were recorded and analyzed.

RESULTS

Mean follow-up time was 4.1 years (range, 12 months to 8 years). Radiographic evaluation indicated solid fusion of odontoid fractures in all cases and no implant failures. No patient reported severe neck pain at follow-up. Neurologicl evaluation showed there was 1- to 2-grade improvement in patients with neurologic deficit. Of patients, 31 reported acceptable outcomes, and 15 reported good outcomes. Range of motion of rotation of the cervical spine and neck disability index score gradually improved significantly during 1 year of follow-up with no obvious change after that. Rate of neck disability index score improvement was 85%.

CONCLUSIONS

Posterior reduction and fixation without fusion can be successfully performed for healing of odontoid fractures with acceptable results and minimal morbidity.