The problems associated with revision surgery.

This article highlights the issue related to revision surgery in spine and the possible implications in the next future. These slides can be retrieved under Electronic Supplementary Material.

Comparative biomechanical study of a new transpedicular vertebral device and vertebroplasty for the treatment or prevention of vertebral compression fractures.

BACKGROUND: A comparative study was performed between a novel transpedicular implant (V-STRUT©, Hyprevention, France) and vertebroplasty. This study aims to assess the biomechanical efficacy of this implant in resurrecting and fortifying the osteoporotic vertebra following a vertebral body fracture. METHODS: A total of 17 vertebrae from 3 human osteoporotic spine segments (T9-L5) were selected. Vertebral compression fractures were generated by eccentric compressive loading until a height reduction of 25%. Then the vertebrae were either fixed using vertebroplasty technique (control group; n = 8) or implanted with V-STRUT© implant combined with bone cement (device group; n = 9). A new compressive loading was performed in the same conditions. Maximal load and stiffness, as well as total energy to fracture were measured. FINDINGS: Fracture force and energy to fracture were both increased either after V-STRUT© implantation or vertebroplasty compared to when the initial fracture was generated. Mean increase percentage between the initial value and the post-treatment value for each parameter were +77% vs +39% regarding fracture load and +126% vs +99% for energy to fracture, for the device group vs vertebroplasty group respectively. No pedicle fractures were observed in both groups, nor implant breaking or bending in the device group. INTERPRETATION: These results show the ability of V-STRUT© combined with bone cement to reinforce the vertebral body strength, with an at least equivalent biomechanical performance as vertebroplasty. Further clinical investigation needs to be undertaken to demonstrate any clinical superiority of V-STRUT© over vertebroplasty.

Focal disorders of the spine with compensatory deformities: how to define them.

PURPOSE: In this paper, the authors propose classifying the epiphenomenon of spinal deformity in two different categories: structural deformity, when the main driver of the observed deformity is a fixed and stiff alteration of the spinal segments, and compensatory deformity, which includes cases where the observed deformity is due to focal abnormalities. This last category comprises, but is not limited to, spinal stenosis, spondylolisthesis, disc herniation, infection or tumor, hip disease or neurological disease (such as Parkinson's disease). METHOD: Narrative review article. RESULTS: We analyzed the focal diseases of the spine that may cause a compensatory deformity inducing adaptation in the unaffected part of the spine. CONCLUSION: The compensatory mechanisms involved in adaptive deformity represent an attempt to maintain a global alignment, to escape from pain or to control body posture. These slides can be retrieved under Electronic Supplementary material.

Total disc arthroplasty versus anterior cervical interbody fusion: use of the Spine Tango registry to supplement the evidence from randomized control trials.

BACKGROUND CONTEXT: Several randomized controlled trials (RCTs) have compared patient outcomes of anterior (cervical) interbody fusion (AIF) with those of total disc arthroplasty (TDA). Because RCTs have known limitations with regard to their external validity, the comparative effectiveness of the two therapies in daily practice remains unknown. PURPOSE: This study aimed to compare patient-reported outcomes after TDA versus AIF based on data from an international spine registry. STUDY DESIGN AND SETTING: A retrospective analysis of registry data was carried out. PATIENT SAMPLE: Inclusion criteria were degenerative disc or disc herniation of the cervical spine treated by single-level TDA or AIF, no previous surgery, and a Core Outcome Measures Index (COMI) completed at baseline and at least 3 months' follow-up. Overall, 987 patients were identified. OUTCOME MEASURES: Neck and arm pain relief and COMI score improvement were the outcome measures. METHODS: Three separate analyses were performed to compare TDA and AIF surgical outcomes: (1) mimicking an RCT setting, with admission criteria typical of those in published RCTs, a 1:1 matched analysis was carried out in 739 patients; (2) an analysis was performed on 248 patients outside the classic RCT spectrum, that is, with one or more typical RCT exclusion criteria; (3) a subgroup analysis of all patients with additional follow-up longer than 2 years (n=149). RESULTS: Matching resulted in 190 pairs with an average follow-up of 17 months that had no residual significant differences for any patient characteristics. Small but statistically significant differences in outcome were observed in favor of TDA, which are potentially clinically relevant. Subgroup analyses of atypical patients and of patients with longer-term follow-up showed no significant differences in outcome between the treatments. CONCLUSIONS: The results of this observational study were in accordance with those of the published RCTs, suggesting substantial pain reduction both after AIF and TDA, with slightly greater benefit after arthroplasty. The analysis of atypical patients suggested that, in patients outside the spectrum of clinical trials, both surgical interventions appeared to work to a similar extent to that shown for the cohort in the matched study. Also, in the longer-term perspective, both therapies resulted in similar benefits to the patients.

A new approach to prevent contralateral hip fracture: Evaluation of the effectiveness of a fracture preventing implant.

BACKGROUND: Among the millions of people suffering from a hip fracture each year, 20% may sustain a contralateral hip fracture within 5 years with an associated mortality risk increase reaching 64% in the 5 following years. In this context, we performed a biomechanical study to assess the performance of a hip fracture preventing implant. METHODS: The implant consists of two interlocking peek rods unified with surgical cement. Numerical and biomechanical tests were performed to simulate single stance load or lateral fall. Seven pairs of femurs were selected from elderly subjects suffering from osteoporosis or osteopenia, and tested ex-vivo after implantation of the device on one side. FINDINGS: The best position for the implant was identified by numerical simulations. The loadings until failure showed that the insertion of the implant increased significantly (P<0.05) both fracture load (+18%) and energy to fracture (+32%) of the implanted femurs in comparison with the intraindividual controls. The instrumented femur resisted the implementation of the non-instrumented femur fracture load for 30 cycles and kept its performance at the end of the cyclic loading. INTERPRETATION: Implantation of the fracture preventing device improved both fracture load and energy to fracture when compared with intraindividual controls. This is consistent with previous biomechanical side-impact testing on pairs of femur using the same methodology. Implant insertion seems to be relevant to support multiple falls and thus, to prevent a second hip fracture in elderly patients.

Outcome of hemivertebra resection in congenital thoracolumbar kyphosis and scoliosis by posterior approach.

OBJECTIVE: To find out the long term outcome of deformity correction by hemivertebra resection in congenital thoracolumbar spinal deformities by a single posterior approach. METHODS: This is a retrospective study carried out at the Department of Spine Surgery, Combined Military Hospital, Rawalpindi, Pakistan from April 2006 to April 2013. All operated patients having single level hemivertebrae of thoracolumbar spine with at least two years follow up were included. Data was analyzed using SPSS ver. 17. RESULTS: There were 24 patients with mean age of 17 years (SD=8.41). Male to female ratio was 9(37.5%): 15(62.5%). Mean operation time was 4.23 hours (SD=1.2). Mean blood loss was 787 ml (SD=479). Mean follow up was for 5 years and 7 months (SD=30 months). Mean pre-op scoliosis was 51 degrees (SD=22), which improved to 20 degrees (SD=15) on last follow up (61% improvement). Mean pre-op kyphosis was 42 degrees (SD=35), which improved to 13 degrees (SD=15) on last follow up (69% improvement). Mean pre-op sagittal shift was 22mm (SD=24.9), which improved to 6mm (SD=9.37) on last follow up (73% improvement). Mean pre-op coronal shift was 34mm (SD=27.1), which improved to 8mm (SD=8.58) on last follow up (76% improvement). Five patients had complications. One proximal junctional kyphosis, one implant failure, one transient deficit and two wound infections. CONCLUSIONS: Posterior resection of hemivertebrae for congenital thoracolumbar deformities gives excellent correction of deformity in experienced hands and has acceptable complication rate.

Pedicle subtraction osteotomies (PSO) in the lumbar spine for sagittal deformities.

INTRODUCTION: The narrow correlation between sagittal alignment parameters and clinical outcomes has been widely established, demonstrating that improper sagittal alignment is a clinical condition that is associated with increased pain and limitations in patients' functional ability. INDICATION: Lumbar pedicle subtraction osteotomy (PSO) is indicated in the treatment of large sagittal (more than 25° of rigid loss of lordosis) deformities of the lumbar spine or its combination with coronal deformity, especially when they are rigid. Indication should be based on careful assessment of the severity of symptoms, functional impairment, functional expectations of the patient, general clinical condition and surgical and anesthesiological team experience. Risk should be carefully assessed and discussed to obtain appropriate informed consent. SURGICAL PROCEDURE: Surgical planning includes selection of the safest levels for the upper and lower instrumented vertebra, site of the osteotomy, modality of fixation, and, most importantly angular value of the correction goal (target lumbar lordosis). Failure to adequately obtain the necessary amount of sagittal correction is the most frequent cause of failure and reoperation. CONCLUSION: PSO is a valuable surgical procedure in correction of severe hypolordosis (=relative kyphosis) in the lumbar spine. It is a demanding procedure for the surgeon, the anesthesiologist and the intensive care team. Although its complication rate is high, it has a substantial positive impact in the quality of life of patients, including the elderly.