Matthew E. Cunningham

Pain and disability determine treatment modality for older patients with adult scoliosis, while deformity guides treatment for younger patients.

Study Design. Multi-center, retrospective review. Objective. Identify age associated clinical and radiographic features correlating with AS treatment. Summary of Background Data. Little information exists about factors determining treatment for adult scoliosis (AS). Existing studies have not evaluated age stratified differences. Methods. Multicenter, retrospective review of 290 patients treated for AS. Patients divided into operative (OP) or nonoperative (NON), and age stratified into 3 groups (G1 = <50 years, G2 = 50–65 years, G3 = >65 years). Demographic and spinopelvic radiographic parameters evaluated. Health-related quality of life (HRQL) measures included SRS-22, Oswestry Disability Index (ODI), visual analog pain scale. Results. Treatment groups (OP, n = 137; NON, n = 153) demonstrated similar age (OP = 52.7 years; NON = 55.5 years; P > 0.05) and cormorbidities. OP had larger thoracic curves than NON (OP = 51°, NON = 45°; P < 0.05). OP had worse HRQL scores than NON (SRS = 2.95 vs. 3.12, P < 0.05; ODI = 33.4 vs. 28.7, P < 0.05; visual analog pain scale = 6.9 vs. 5.6, P < 0.05, respectively). Age stratification of OP demonstrated larger curves in G1 and G2 versus G3, progressively worsening sagittal imbalance in older age groups, and worse HRQL scores in G3 versus G1 and G2. Age stratification of NON demonstrated worsening sagittal imbalance with age, however, other radiographic values and HRQL scores were similar between all NON age groups. Treatment stratification of age groups demonstrated G1-OP had greater deformity than G1-NON (mean thoracic curve: G1-OP = 53°, G1-NON = 43°; P < 0.05) but similar HRQL values. Whereas G2 and G3-OP had similar radiographic coronal and sagittal values as G2 and G3-NON, but worse HRQL scores. Conclusion. Counter to previous reports, age, cormorbidities, and sagittal balance did not influence treatment modality for AS. Operative treatment for younger patients was driven by increased coronal plane deformity. Conversely, pain and disability mandated treatment for olderpatients, independent of radiographic measures. These findings suggest that AS patients do not become uniformly disabled with age, and that disability can not be solely predicted by radiographic findings. These data should be considered when considering treatment for AS.

Parathyroid Hormone (1-34) Augments Spinal Fusion, Fusion Mass Volume, and Fusion Mass Quality in a Rabbit Spinal Fusion Model

Study Design. The posterolateral rabbit spinal fusion model was used to assess the effect of intermittent parathyroid hormone on spinal fusion outcomes. Objective. To test the hypothesis that intermittent parathyroid hormone (PTH) improves spinal fusion outcomes in the rabbit posterolateral spinal fusion model. Summary of Background Data. Spinal fusion is the definitive management for spinal deformity or instability, yet despite current technology, 5% to 40% of lumbar fusions result in pseudarthrosis. Animal studies have demonstrated enhanced fracture healing with the use of PTH, but the effect of PTH on spinal fusion is poorly described. Methods. Forty-four male New Zealand white rabbits underwent bilateral posterolateral spine fusion (L5–L6 level). Twenty-two rabbits received daily subcutaneous injections of PTH (1–34) (10 &mgr;g/kg) and 22 received an injection of saline fluid. All were killed 6 weeks after surgery. L5–L6 vertebral segments were removed and analyzed with manual bending, faxitron radiography, microCT, and histomorphometry. Results. Manual bending identified fusion in 30% (control) versus 81% (PTH) animals (P < 0.001). A radiographic scoring system (“0” = no bone formation, “5” = full fusion) resulted in an average score of 3.36 (control) versus 4.51 (PTH) (P < 0.001). MicroCT analysis demonstrated a median mass of 3.5 cc (control) (range, 2.25–5.40 cc) versus 6.03 cc (PTH) (range, 4.34–10.58 cc) (P < 0.001). Histology showed a median percentage bone area of 14.3% (control) (n = 12) versus 29.9% (PTH) (n = 15) (P < 0.001). The median percentage cartilage was 2.7% (control) (n = 5) versus 26.6% (PTH) (n = 5) (P < 0.01). Osteoclast quantification revealed median values of 140.5 (control) (n = 6) and 345.0 (PTH) (n = 8) (P < 0.001) respectively, and the percentage of osteoblasts revealed a median value of 31.4% (control) (n = 6) versus 64.4% (PTH) (n = 8) (P < 0.001). Conclusion. Intermittent PTH administration increased posterolateral fusion success in rabbits. Fusion bone mass and histologic determinants were also improved with PTH treatment. PTH has promise for use as an adjunctive agent to improve spinal fusion in clinical medicine.

Degenerative Lumbar Spinal Stenosis: Evaluation and Management

&NA; Degenerative lumbar spinal stenosis is caused by mechanical factors and/or biochemical alterations within the intervertebral disk that lead to disk space collapse, facet joint hypertrophy, soft‐tissue infolding, and osteophyte formation, which narrows the space available for the thecal sac and exiting nerve roots. The clinical consequence of this compression is neurogenic claudication and varying degrees of leg and back pain. Degenerative lumbar spinal stenosis is a major cause of pain and impaired quality of life in the elderly. The natural history of this condition varies; however, it has not been shown to worsen progressively. Nonsurgical management consists of nonsteroidal anti‐inflammatory drugs, physical therapy, and epidural steroid injections. If nonsurgical management is unsuccessful and neurologic decline persists or progresses, surgical treatment, most commonly laminectomy, is indicated. Recent prospective randomized studies have demonstrated that surgery is superior to nonsurgical management in terms of controlling pain and improving function in patients with lumbar spinal stenosis.

Early outcomes and complications of posterior vertebral column resection.

BACKGROUND CONTEXT Hyperkyphosis confers a significant risk for neurologic deterioration as well as compromised cardiopulmonary function. Posterior vertebral column resection (PVCR) is a challenging but effective technique for spinal cord decompression and deformity correction that even under the setting of limited resources can be performed to reduce the technical difficulties, the operating time, and possibly the complications of the traditional two-staged vertebral column resection (VCR). PURPOSE To report on the results of VCR performed through a single posterior approach (PVCR) in the treatment of severe rigid kyphosis in a series of patients treated and followed at a Scoliosis Research Society Global Outreach Program site in West Africa. STUDY DESIGN Retrospective case series. PATIENT SAMPLE Forty-five consecutive patients treated with PVCR for correction of severe rigid kyphosis. OUTCOME MEASURES Clinical and radiographic outcomes and complications; Scoliosis Research Society outcome instrument (SRS-22). METHODS From 2002 to 2009, 45 patients (20 male and 25 female) underwent PVCR for kyphosis from congenital deformity (nine) or secondary to tuberculosis of the spine (36). Preoperative demographics, preop and postop neurologic status, SRS-22 scores and complications were recorded; upright full spine X-rays were available in all patients. Mean age was 14 years (6-47 years); mean follow-up 27 months (2-79 months). Mean preoperative kyphosis measured 108°. The deformity apex was resected via a costotransverse (thoracic) or posterolateral (lumbar) approach; neurosurveillance with sensory (somatosensory-evoked potentials) and motor (motor-evoked potentials) potential was used in all cases. Posterior instrumentation was used in all patients, and anterior structural cage was used in 32 patients. RESULTS Intraoperative monitoring changes occurred in 10 patients (22%), and one patient progressed to complete spinal cord injury. Average preoperative local kyphosis was 108° and corrected to 600 postoperatively. Postoperatively, no additional patient showed neurologic deterioration; of the 11 patients with preoperative gait disturbances, 4 improved to normal gait, 5 remained the same, and 2 showed deterioration of their walking ability to nonambulating level. Total SRS-22 scores improved from 3.18 to 3.54 (p=.01), primarily self-image domain. CONCLUSIONS Posterior vertebral column resection was successfully undertaken for the management of thoracic and thoracolumbar hyperkyphosis, demonstrating improvements in overall kyphosis and clinical outcome. Neuromonitoring provided the required safety to perform these challenging complex spine deformity procedures.

Image-based tissue engineering of a total intervertebral disc implant for restoration of function to the rat lumbar spine

Nonbiological total disc replacement is currently being used for the treatment of intervertebral disc (IVD) disease and injury, but these implants are prone to mechanical wear, tear and possible dislodgement. Recently, tissue‐engineered total disc replacement (TE‐TDR) has been investigated as a possible alternative to more fully replicate the native IVD properties. However, the performance of TE‐TDRs has not been studied in the native disc space. In this study, MRI and microcomputed tomography imaging of the rat spine were used to design a collagen (annulus fibrosus)/alginate (nucleus pulposus) TE‐TDR to a high degree of geometric accuracy, with less than 10% difference between TE‐TDR and the native disc dimensions. Image‐based TE‐TDR implants were then inserted into the L4/L5 disc space of athymic rats (n = 5) and maintained for 16 weeks. The disc space was fully or partially maintained in three of five animals and proteoglycan and collagen histology staining was similar in composition to the native disc. In addition, good integration was observed between TE‐TDR and the vertebral bodies, as well as remnant native IVD tissue. Overall, this study provides evidence that TE‐TDR strategies may yield a clinically viable treatment for diseased or injured IVD. Copyright

The effect of therapies for osteoporosis on spine fusion: a systematic review

BACKGROUND CONTEXT Fusion of the spine requires de novo bone formation and remodeling, processes that rely heavily on the action of the osteoblast and osteoclast. Bisphosphonate drugs and intermittent parathyroid hormone (PTH) therapy are widely prescribed to treat osteoporosis and act on the osteoblast/osteoclast complex. The impact of these medications on spine fusion is not known. PURPOSE To evaluate the available evidence on the potential impact of bisphosphonates and PTH on fusion rate and fusion quality in spinal arthrodesis. STUDY DESIGN A systematic review of the literature. PATIENT SAMPLE All available literature regarding the impact of bisphosphonates and PTH on spinal fusion. OUTCOME MEASURES Fusion rate and histologic, microstructural, or biomechanical measures of fusion quality. METHODS A systematic review of the literature published between 1980 and 2011 was conducted using major electronic databases. The results of studies meeting criteria for inclusion were then aggregated and examined for consensus on the effect of these medications on spine fusion. RESULTS The literature contained 18 animal studies and one clinical trial investigating the impact of these medications on spine fusion. Most animal studies evaluating the impact of bisphosphonates on fusion rate have not found statistically significant changes with treatment, although this fact may be attributable to low statistical power. The animal literature does suggest that bisphosphonate therapy results in a less histologically mature fusion mass; however, the impact of these changes on fusion mass biomechanics is unclear. The only available human study suggests that these bisphosphonates may increase the radiographically defined fusion rate but did not demonstrate an impact on clinical outcome. In animals, PTH improves the fusion rate and fusion mass microstructure, but data on its effect on fusion mass biomechanics are lacking. No studies have evaluated the impact of PTH on spine fusion in humans. CONCLUSIONS In animals, bisphosphonate therapy appears to impede maturation of the fusion mass, with an unclear effect on mechanical strength. This effect was not seen in the lone human study, which suggested that these medications improved the radiographically defined fusion rate. The available animal studies on intermittent PTH treatment suggest that it may improve fusion rate and fusion mass microstructure. Given the widespread use of these agents, further investigation into their impact on human spine fusion is necessary to inform the care of patients with osteoporosis who are undergoing spine surgery.

Late treatment of tuberculosis-associated kyphosis: literature review and experience from a SRS-GOP site.

IntroductionSpinal tuberculosis (TB) accounts for approximately half of all cases of musculoskeletal tuberculosis. Kyphosis is the rule in spinal tuberculosis and has potential detrimental effects on both the spinal cord and pulmonary function. Late-onset paraplegia is best avoided with the surgical correction of severe kyphosis, where at the same time anterior decompression of the cord is performed and the remnants of the tuberculosis-destroyed vertebral bodies are excised.Material and methodsReview of the literature on late surgical treatment of TB-associated kyphosis; description and comparative analysis of the different surgical techniques.ResultsKyphosis can be corrected either at the acute stage or at the healed late stage of tuberculous infection. In the late stage, the stiffness of the spine and chronic lung disease are additional considerations for the surgical approach and technique. Contrary to the traditional anterior transpleural approach used in the acute spinal tuberculosis infection, extrapleural approaches, either antero-lateral or direct posterior, are favored in late treatment.ConclusionThe correction of deformity is only feasible with three-column osteotomies, and posterior vertebral column resection (PVCR) is the treatment of choice in extreme kyphosis. The prognosis of the neurologic deficit (late paraplegia) is dependent on the extent of gliosis of the spinal cord.

Fusionless scoliosis surgery

Purpose of review Severe spinal deformity in young children is a formidable challenge for optimal treatment. Standard interventions for adolescents and adults, including spinal deformity correction and fusion, may not be appropriate for young patients with considerable growth remaining. Alternate surgical options that provide deformity correction and protect the growth remaining in the spine are needed to treat this population of patients best. Recent findings Several groups have reported very exciting advances in the field of deformity spine surgery. Updated findings concerning the successful implementation of growing rods have revived this technique as a viable option for preserving near normal growth of the spine. New techniques have also been recently described, including vertebral stapling that produces asymmetric and corrective growth of the concavity of a deformity, and vertical expandable prosthetic titanium rib instrumentation that indirectly corrects spine deformity and protects spine growth remaining to treat an associated thoracic insufficiency syndrome. Summary New techniques and instrumentation at the disposal of spine surgeons allow the treatment of this challenging patient population to approach the goals of deformity correction and maintenance with preservation of potential growth. Preliminary outcomes from the different techniques are promising, but further investigation, including long-term follow-up, is necessary.

Modern biologics used in orthopaedic surgery.

Purpose of reviewIn this review we summarize some of the most recent research in the area of local bone regeneration. These innovations may be relevant in the orthopaedic treatment of patients with rheumatoid arthritis, or other inflammatory arthridities, as such patients often present with inadequate bone stock. Recent findingsBone grafting remains the standard treatment for bone deficiency. Several new approaches, such as the use of concentrated blood products or osteoprogenitor cells in conjunction with grafts, have been developed but remain to be tested clinically. Experimental studies have elucidated important aspects of the biology of bone graft remodeling and osteoprogenitor cell differentiation. Materials that can serve as graft alternatives continue to be developed. Positive experimental findings have resulted from combinations of such materials with osteoprogenitor cells or osteoinductive factors such as bone morphogenetic proteins. SummaryWhile few studies to date have examined the specific use of these new strategies in the setting of rheumatoid arthritis, many hold promise for patients with rheumatoid arthritis and other inflammatory and metabolic conditions that affect bone quality and quantity.

Variations in Sagittal Alignment Parameters based on Age: A Prospective Study of Asymptomatic Volunteers using Full-Body Radiographs.

Study Design. Cross-sectional cohort study. Objective. Describe age-stratified normative values of traditional and novel sagittal alignment parameters. Summary of Background Data. Full-body radiographic techniques can capture coronal and sagittal standing images from the occiput to the foot without stitching or vertical distortion. This provides an ideal method to evaluate measures of global alignment. Methods. Adults with no back or neck symptoms were recruited. Age, body mass index, Neck Disability Index, and Oswestry Disability Index scores were recorded. The following parameters were measured: center sacral vertebral line, Occiput-C2 (O-C2) lordosis, cervical lordosis (C2-C7, CL), thoracic kyphosis (T2-12, TK), T2-T5 kyphosis, T5-T12 kyphosis, thoracolumbar kyphosis (T10-L2), lumbar lordosis (L1-S1, LL), sacral slope, pelvic tilt, pelvic incidence (PI), knee flexion angle, global sagittal angle, T1-pelvis angle, C2-S1 sagittal vertical axis (SVA), C7-S1 SVA, Basion-C7 SVA, B-S1 SVA and Basion to the center of the femoral head SVA and PI minus LL. Comparisons of sagittal alignment parameters between different age groups were performed. A Pearson correlation was used to determine relationships. Results. One hundred fifteen volunteers had imaging suitable for analysis; average age as 50.1 years (range 22–78), average body mass index was 28, average Neck Disability Index was 3.4 ± 4.4, and average Oswestry Disability Index was 1.7 ± 4.9. CL (r = −0.34, P = 0.001), T1-pelvis angle (r = 0.44, P < 0.001), knee flexion angle (r = 0.42, P < 0.001), global sagittal angle (r = 0.56, P < 0.001), and C7 SVA (r = 0.46, P < 0.001) all increased with age. LL decreased with age (r = 0.212, P = 0.039). We were able to establish a chain of correlation extending from the toes to the occiput and report age-based normative values for all parameters. Conclusion. We describe age-based normative sagittal alignment parameters in the adult spine with complete visualization from the occiput to the feet. We describe compensatory changes that occur to maintain sagittal balance. These values may be used as a reference for future studies. Level of Evidence: 4