Faculty Bibliography

BACKGROUND: Expansion thoracoplasty is a temporary solution to allow complete pulomonary development in the setting of vertebral and rib cage deformities. After thoracoplasty, an expandable implant is needed to maintain the correction. The Growing Spine Profiler (GSP) is a new type of readjustable rib distracter. The purpose of this study was to evaluate the experiences of surgeons in Europe with the implantation of the GSP. METHODS: We retrospectively reviewed 44 patients that underwent placement of the GSP at 15 sites throughout Europe. The mean age at the time of surgery was 6.24 years. Basic demographic data and postoperative management were reviewed. All patients received an opening-wedge thoracostomy with device implantation and expansion thoracoplasty. Retrospectively, the original indications for implantation were determined. Digital images of the radiographs were used to measure coronal and sagittal parameters. RESULTS: The most common diagnoses for implantation were hemivertebrae (9), hemivertebrae with chest wall deformity (10), and unilateral bar (8). Outcomes were available for 43 patients with a mean follow-up period of 3.07 years. There were 23 patients that had an adverse event. Rib fractures were the most common adverse event, with 8 incidents in 7 patients. Radiographically, coronal curve magnitudes were maintained, whereas sagittal kyphosis gradually increased. CONCLUSIONS: The GSP was effective in the maintenance of deformity, while providing a moderate complication rate. Further studies need to be performed to determine the safety and efficacy of this implant

BACKGROUND: Iliac crest harvest has been considered the "gold standard" at producing successful arthrodesis of the lumbar spine but is also associated with many donor-site morbidities. Many alternatives have been used to avoid iliac crest harvest, including autologous bone from other donor sites, allogeneic bone, ceramics, and recombinant human bone morphogenetic proteins (rhBMPs). This review will highlight the properties and preparations of these graft types and their potential complications and reported clinical efficacy. METHODS: A Medline search was conducted via PubMed by use of the following terms in various combinations: lumbar fusion, freeze-dried allograft, fresh-frozen allograft, autograft, iliac crest, demineralized bone matrix, rhBMP-2, rhBMP-7, scoliosis, bone marrow aspirate, HEALOS, coralline hydroxyapatite, beta tricalcium phosphate, synthetic, ceramics, spinal fusion, PLF, PLIF, ALIF, and TLIF. Only articles written in English were assessed for appropriate material. Related articles were also assessed depending on the content of articles found in the original literature search. CONCLUSIONS: Although iliac crest remains the gold standard, reported success with alternative approaches, especially in combination, has shown promise. Stronger evidence with limited sources of potential bias is necessary to provide a clear picture of their clinical efficacy.

STUDY DESIGN: Prospective inter-rater and intrarater reliability analysis. OBJECTIVE: To compare the inter-rater and intrarater reliability of magnetic resonance imaging (MRI) and computed tomography (CT) for grading of facet arthropathy as well as determining whether there is a contraindication to total disc replacement (TDR). SUMMARY OF BACKGROUND DATA: Several classifications attempted to evaluate lumbar facet joints and their degree of arthropathy. The Fujiwara-MRI and Pathrea-CT classifications remain the most commonly used. METHODS: A total of 10 fellowship-trained orthopedic spine surgeons and 3 orthopedic spine fellows evaluated 50 levels from L3-L4 through L5-S1 on parallel axial MRI (T1 and T2) and CT images. The degree of osteoarthritis was graded on a 4-point scale (Fujiwara-MRI and Pathrea-CT). Surgeons evaluated whether the degree of facet disease represented a contraindication to TDR. Grading was performed during 2 sessions. Weighted kappa statistics were used to describe inter- and intraobserver agreement. RESULTS: The inter-rater reliability for MRI was 0.21 and 0.07 (fair to slight) among attendings and fellows, respectively. inter-rater reliability for CT was 0.33 and 0.27 (fair), respectively. The mean intrarater reliability for MRI was fair, 0.36 (attendings) and 0.26 (fellows). The mean intrarater reliability for CT was moderate, 0.52 (attendings) and 0.51 (fellows). For possible TDR contraindication, the inter-rater reliability for MRI was 0.22 and 0.01 (fair to slight) among attendings and fellows, respectively. Inter-rater reliability for CT was 0.33 and 0.45 (fair), respectively. The mean intrarater reliability for MRI was fair, 0.36 (attendings) and 0.26 (fellows). The mean intrarater reliability for CT was moderate, 0.52 (attendings) and 0.51 (fellows). CONCLUSION: The current grading system for facet arthropathy has only fair agreement. CT is slightly more reliable for grading. Intrarater reliability was only fair for MRI and moderate for CT. Only limited agreement existed between surgeons as to the extent of facet disease that would pose as a contraindication for TDR

STUDY DESIGN: Biomechanical study of bovine spines. OBJECTIVE: The purpose of this study was to perform a biomechanical test to analyze intervertebral deflections following placement of both 1 and 2 semiconstrained TDRs in the subjacent segments of a long fusion. SUMMARY OF BACKGROUND DATA: Long-term sequela of long lumbar fusion for scoliosis include adjacent segment disease and flatback syndrome. Total disc replacement (TDR) is a viable option for the treatment of these conditions. Little data has been published regarding the placement of a TDR distal to a scoliosis fusion. METHODS: Six thoracolumbar bovine spines (T12-S1) were instrumented from T12 to L5, with bilateral pedicle screw fixation at each level. L5-L6 and L6-S1 served as the test levels. One TDR (FlexiCore, Stryker Spine, Allendale, NJ) was initially performed adjacent to the fusion, followed by a subsequent TDR insertion at the last spinal segment. The applied load, total specimen deflection, and local transducer deflections were recorded before and after a TDR at both levels. The results were expressed as a percentage of the intact specimen. Flexion, extension, lateral bending, and torsional deflections were recorded. RESULTS: There were no significant differences (P > 0.05) in sensor deflection observed at the L5-L6 and L6-S1 levels in the anterior and lateral transducers when compared to intact spines specimens. A similar effect was observed at the L5-L6 and L6-S1 levels in the anterior and lateral transducers when compared to intact or prior L5-L6 and intact L6-S1 constructs. CONCLUSION: This study has shown that using the FlexiCore system at 1 and/or 2 intervertebral disc spaces caudal to a scoliosis fusion model did not significantly change the sensor deflection at the 2 segments adjacent to a scoliosis fusion construct. Future research will continue to define the clinical setting and patients best suited for management by TDR systems