Computerized preoperative planning for correction of sagittal deformity of the spine

Purpose  

Various methods of preoperative planning have been described for the correction of spinal sagittal deformities. They are reliable on condition that the thoracolumbar spine is totally fused and enable only the simulation of pedicle subtraction osteotomy (PSO). In this study, a new theoretical planning that can be used regardless of the etiology of the deformity and the type of osteotomy is described and assessed.     

Structured coculture of stem cells and disc cells prevent disc degeneration in a rat model

Background contextHarnessing the potential of stem cells is an important strategy for regenerative medicine. This study explores the use of bilaminar coculture pellets (BCPs) of mesenchymal stem cells (MSCs) and nucleus pulposus cells (NPCs) as a cell-based therapy for intervertebral disc regeneration. Prior in vitro experiments have shown that BCP can help differentiate MSCs and substantially improve new matrix deposition.PurposeTo evaluate the clinical relevance of BCPs by testing the system in vivo.Study design/settingWe have designed a novel spherical BCP where MSCs are enclosed in a shell of NPCs. The pellets were tested in vivo in a rat tail model of disc degeneration.MethodsRat caudal intervertebral discs were denucleated and treated with BCP in a fibrin sealant (FS) carrier (controls were MSCs suspended in FS; NPCs suspended in FS; MSCs and NPCs suspended in FS; FS only; and surgery only). At 14 and 35 days after implantation, the animals were euthanized and discs were evaluated for proteoglycan content, enzyme-linked immunosorbent assay for inflammatory cytokines, cell retention using polymerase chain reaction, disc height, histology, and disc grade based on a blinded scoring system.ResultsThe proteoglycan and cytokine levels were not significantly different among groups. The BCP group had higher cell retention than controls. Disc height and disc grade increased over time only in the BCP group. Bilaminar coculture pellets were the only treatment to show proteoglycan staining in the nucleus space at 35 days.ConclusionsThis study shows that BCPs may prevent postnucleotomy disc degeneration in vivo. Larger animals and longer time points will be necessary to further judge potential clinical impact. As opposed to strategies that require growth factor supplements, predifferentiation, or genetic manipulations, BCPs are a self-sustaining and targeted method for tissue regeneration in situ.     

Surgery improves pain,function and quality of life in patients with spinal metastases: a prospective study on 118 patients

Purpose  

There are few prospective studies on surgical outcomes and survival in patients with metastatic disease to the spine. The magnitude and duration of effect of surgery on pain relief and quality of life remains uncertain. Therefore, the aim of this clinical study was to prospectively evaluate clinical, functional, quality of life and survival outcomes after palliative surgery for vertebral metastases.     

The Mobi-C® cervical disc prosthesis: indications, technique and results

The Mobi-C® cervical disc replacement is a semi-constrained prosthesis with a mobile polyethylene insert situated between two chrome cobalt plates. The insert can slide. Overall the Mobi-C® device has five degrees of freedom. The primary indications are as follows: 1) soft herniated discs leading to cervicobrachial pain refractory to conservative treatment; 2) some cases of hard herniated discs if movement has been documented on intra-operative dynamic bending films; 3) much more rarely in cases of spinal cord compression with myelopathy. Technically, centering of the device is facilitated by the dedicated instrument system. Regarding the results, the clinical efficacy is conventional. Mobility is preserved at a minimum 2-year follow-up in 85.5% of the devices. The main mechanical complications are radiological adjacent syndrome and heterotopic ossification (HO), among which even those of class III permit residual movement.     

Intraspinal canal rod migration causing late-onset paraparesis 8 years after scoliosis surgery

Introduction

Complete intraspinal canal rod migration with posterior bone reconstitution has never been described in the adolescent idiopathic scoliosis (AIS) population. We present an unusual but significant delayed neurological complication after spinal instrumentation surgery.

Case report

A 24-year-old woman presented with lower limb weakness (ASIA D) 8 years after posterior instrumentation from T2 to L4 for AIS. CT scan and MRI demonstrated intra-canal rod migration with complete laminar reconstitution. The C-reactive protein was slightly elevated (fluctuated between 10 and 20 mg/l). Radiographs showed the convex rod had entered the spinal canal. The patient was taken into the operating room for thoracic spinal decompression and removal of the convex rod. This Cotrel–Dubousset rod, which had been placed on the convexity of the thoracic curve had completely entered the canal from T5 to T10 and was totally covered by bone with the eroded laminae entirely healed and closed. There was no pseudarthrosis. Intra-operatively, the fusion mass was opened along the whole length of this rod and the rod carefully removed and the spinal cord decompressed. The bacteriological cultures returned positive for Propionibacterium acnes. The patient recovered fully within 2 months post-operatively.

Conclusion

We opine that the progressive laminar erosion with intra-canal rod migration resulted from mechanical and infectious-related factors. The very low virulence of the strain of Propionibacterium acnes is probably involved in this particular presentation where the rod was trapped in the canal, owing to the quite extensive laminar reconstitution.

     

3D postural balance with regard to gravity line: an evaluation in the transversal plane on 93 patients and 23 asymptomatic volunteers

Relevance of posture assessment has been reported in case of spine disorders. This study explores the interest in quantifying posture using 3D reconstruction from biplanar X-rays in free standing position and a force plate. 93 patients consulting for spine disorders were divided (‘3D deformity’, ‘sagittal imbalance’ and ‘mild deformity’) and compared with 23 asymptomatic volunteers. Registration of the gravity line (GL) in reconstruction yielded transversal position of the center of acoustic meati (CAM) T1, T4, T9, L3, S1 and hip axis (HA) with regard to GL. Transversal position of CAM and L3 appeared as relevant parameters to discriminate patients from volunteers. Sagittal inclination of the axis linking the CAM to HA was correlated with position of the CAM to GL (r = 0.92 for patients). In conclusion, observing posture in 3D with regard to GL provides clinical relevant information. CAM-HA inclination may improve postural evaluation without force plate.