History of spinal osteotomy.

Spinal deformity is one of the oldest known diseases with descriptions documented many of the earliest civilizations. Historical treatments have had little efficacy, especially in adults. However, in the modern era, there has been a rapid expansion of new technologies and surgical techniques aided by advances in supportive care that now allow the spinal surgeon to have powerful tools to correct spinal deformity. In this manuscript, we review the origins of spinal deformity surgery and the development of spinal instrumentation. The focus of the manuscript is to review the relationship of these developments to the implementation of spinal osteotomies for deformity correction.

Long-term outcomes after posterior spine fusion for adolescent idiopathic scoliosis.

PURPOSE OF REVIEW: To summarize recent literature regarding long-term follow-up after spinal fusion for patients with adolescent idiopathic scoliosis. In particular, this review includes a review of research which provides insight into long-term results after fusion using pedicle screw stabilization, a relatively new technique for which long-term follow-up is only recently available. RECENT FINDINGS: The literature increasingly uses patient-derived questionnaires to report outcomes. Minor residual scoliosis after fusion does not adversely affect outcomes and is well tolerated by patients without causing functional limitations. In contrast, patients who are leaning forward after fusion ('positive sagittal balance') do worse as measured by validated outcomes instruments. Although patients who undergo long fusion have higher rates of disc degeneration on magnetic resonance imaging compared with the general population, this degeneration is most often clinically silent. SUMMARY: The best available evidence suggests that most patients do well after posterior fusion for adolescent idiopathic scoliosis, although outcomes are adversely affected if patients develop positive sagittal balance. Continued surveillance will determine whether accelerated degeneration at unfused levels becomes symptomatic at longer-term follow-up or remains clinically silent.

The effect of omega-3 fatty-acid supplements on perioperative bleeding following posterior spinal arthrodesis.

PURPOSE: To investigate the effect of omega-3 fatty-acid supplements (n-3FA) on bleeding during posterior spinal arthrodesis. METHODS: We reviewed all one- or two-level posterolateral lumbar decompression/fusions with or without interbody fusion by five surgeons within 3 years. Patients taking n-3FA preoperatively were matched 1:2 with controls based on procedure, surgeon and operative time. Patients with abnormal coagulation parameters, known bleeding disorders or other medications that could affect surgical blood loss were excluded. RESULTS: Twenty-eight patients met inclusion criteria. The n-3FA and control groups were similar with respect to gender, age, body mass index, operative time, and preoperative use of non-steroidal anti-inflammatory drugs. The n-3FAs were stopped an average of 5.2 days before surgery (range 1-10). Mean estimated blood loss (EBL) was 697 ml in the n-3FA group and 771 ml in the control group (p = 0.36). Mean transfused volume of Cell Saver (CS) was 282 ml in the n-3FA group and 321 ml in the control group (p = 0.30). A post hoc power analysis showed that the study was powered to detect a minimum difference of 105 ml for EBL and 50 ml for CS. The multivariate generalized estimating equation did not show a significant difference between groups for EBL or CS (p = 0.35 and p = 0.29, respectively). Secondary outcomes including drop in postoperative hemoglobin, transfusion requirement, complications and surgical drain output were similar between the two groups. CONCLUSIONS: The n-3FA use did not contribute to higher perioperative blood loss during spinal arthrodesis.

Postoperative infections of the lumbar spine: presentation and management.

PURPOSE: Postoperative surgical site infections (SSI) are a frequent complication following posterior lumbar spinal surgery. In this manuscript we review strategies for prevention, diagnosis and treatment of SSI. METHODS: The literature was reviewed using the Pubmed database. RESULTS: We identified fifty-nine relevant manuscripts almost exclusively composed of Level III and IV studies. CONCLUSIONS: Risk factors for SSI include: 1) factors related to the nature of the spinal pathology and the surgical procedure and 2) factors related to the systemic health of the patient. Staphylococcus aureus is the most common infectious organism in reported series. Proven methods to prevent SSI include prophylactic antibiotics, meticulous adherence to aseptic technique and frequent release of retractors to prevent myonecrosis. The presentation of SSI is varied depending on the virulence of the infectious organism. Frequently, increasing pain is the only presenting complaint and can lead to a delay in diagnosis. Magnetic resonance imaging and the use of C-reactive protein laboratory studies are useful to establish the diagnosis. Treatment of SSI is centered on surgical debridement of all necrotic tissue and obtaining intra-operative cultures to guide antibiotic therapy. We recommend the involvement of an infectious disease specialist and use of minimum serial bactericidal titers to monitor the efficacy of antibiotic treatment. In the most cases, SSI can be adequately treated while leaving spinal instrumentation in place. For severe SSI, repeat debridement, delayed closure and involvement of a plastic surgeon may be necessary.

Empirical evaluation of the inter-relationship of articular elements involved in the pathoanatomy of knee osteoarthritis using magnetic resonance imaging.

BACKGROUND: In this cross-sectional study, we conducted a comprehensive assessment of all articular elements that could be measured using knee MRI. We assessed the association of pathological change in multiple articular structures involved in the pathoanatomy of osteoarthritis. METHODS: Knee MRI scans from patients over 45 years old were assessed using a semi-quantitative knee MRI assessment form. The form included six distinct elements: cartilage, bone marrow lesions, osteophytes, subchondral sclerosis, joint effusion and synovitis. Each type of pathology was graded using an ordinal scale with a value of zero indicating no pathology and higher values indicating increasingly severe levels of pathology. The principal dependent variable for comparison was the mean cartilage disease score (CDS), which captured the aggregate extent of involvement of articular cartilage. The distribution of CDS was compared to the individual and cumulative distributions of each articular element using the Chi-squared test. The correlations between pathological change in the various articular structures were assessed in a Spearman correlation table. RESULTS: Data from 140 patients were available for review. The cohort had a median age of 61 years (range 45-89) and was 61% female. The cohort included a wide spectrum of OA severity. Our analysis showed a statistically significant trend towards pathological change involving more articular elements as CDS worsened (p-value for trend < 0.0001). Comparison of CDS to change in the severity of pathology of individual articular elements showed statistically significant trends towards more severe pathology as CDS worsened for osteophytes (p-value for trend < 0.0001), bone marrow lesions (p = 0.0003), and subchondral sclerosis (p = 0.009), but not joint effusion or synovitis. There was a moderate correlation between cartilage damage, osteophytes and BMLs as well as a moderate correlation between joint effusion and synovitis. However, cartilage damage and osteophytes were only weakly associated with synovitis or joint effusion. CONCLUSION: Our results support an inter-relationship of multiple articular elements in the pathoanatomy of knee OA. Prospective studies of OA pathogenesis in humans are needed to correlate these findings to clinically relevant outcomes such as pain and function.

Postoperative pain following posterior iliac crest bone graft harvesting in spine surgery: a prospective, randomized trial.

BACKGROUND CONTEXT: Postoperative pain at the site of bone graft harvest for posterior spine fusion is reported to occur in 6%-39% of cases. However, the area around the posterior, superior iliac spine is a frequent site of referred pain for many structures. Therefore, many postoperative spine patients may have pain in the vicinity of the posterior iliac crest that may not in fact be caused by bone graft harvesting. The literature may then overestimate the true incidence of postoperative iliac crest pain. PURPOSE: We performed a prospective study testing the hypothesis that patients will not report significantly higher visual analog scores over the graft harvest site when compared with the contralateral, non-harvested side. STUDY DESIGN/SETTING: This is a prospective, randomized cohort study. PATIENT SAMPLE: Patients aged 18-75 years undergoing elective spinal fusion of one to two levels between L4 and S1 for spinal stenosis and spondylolisthesis were randomized to left-sided or right-sided iliac crest bone graft (ICBG) donor sites and blinded to the side of harvest. OUTCOME MEASURES: Primary outcome was a 10-point visual analog scale (VAS) for pain over the left and right posterior superior iliac spine. METHODS: Bone graft was harvested via spinal access incisions without making a separate skin incision over the crest. Each patient's non-harvested side served as an internal control. Data points were recorded by patients on their study visit sheets preoperatively and at 6 weeks, 3 months, 6 months, and 1 year postoperatively. RESULTS: Forty patients were enrolled in the study (23 females) with an average follow-up of 8.1 months (1.5-12 months). Mean age was 51.7 years (23-77 years). Left- and right-side ICBG harvesting was performed equally between the 40 patients. The average volume of graft harvested from the left was 35.3 mL (15-70 mL) and 36.1 mL (15-60 mL) from the right. There was no statistical difference between preoperative VAS score on the harvested side compared with the non-harvested side (p=.415). Postoperatively, there were consistently higher VAS scores on the operative side; however, these differences were not statistically significant at 6 weeks (p=.111), 3 months (p=.440), 6 months (p=.887), or 12 months (p=.240). Both groups did, however, show statistically significant improvements in VAS scores over time within the operative and nonoperative sides (p<.05). Graft volume had no effect on the VAS scores (p=.382). CONCLUSIONS: The current literature does not adequately illuminate the incidence of postoperative pain at the site of harvest and the relative magnitude of this pain in comparison with the patient's residual low back pain. This is the first study to blind the patient to the laterality of bone graft harvesting. Our randomized investigation showed that although pain on the surgical side was slightly higher, it was neither clinically nor statistically different from the nonsurgical side. Our conclusion supports surgeons' use of autologous bone graft, which offers a cost-effective, efficacious spinal fusion supplement.

Factors predicting functional and radiographic outcomes after arthroscopic partial meniscectomy: a review of the literature.

We reviewed articles examining the associations between factors identifiable before or during arthroscopic partial meniscectomy (APM) and functional and radiographic outcomes. We assessed the magnitude of effect and statistical significance of associations between predictor variables and outcomes within each study. We then qualitatively synthesized these observations across multiple studies. Twenty-five studies met our criteria for inclusion. Eight of the studies had a prospective design. There were no randomized, controlled trials. The studies had important methodological limitations. Greater size of meniscal resection and female gender showed the strongest and most consistent associations with greater radiographic evidence of osteoarthritis across multiple studies. Greater articular cartilage degeneration assessed at surgery, greater size of meniscal resection, greater laxity of the anterior cruciate ligament, and prior surgery on the index knee were the strongest predictors of worse functional outcomes. Patients with worse preoperative health status (SF-36 score <60), Workers' Compensation, and pending litigation had worse functional outcomes, but these factors were examined in only 1 study. There was consistently no significant difference in radiographic or functional outcome between medial or lateral meniscal injury. Clinicians should incorporate these predictors of outcome into their conversations with patients regarding the advantages and drawbacks of APM.

Extreme Lateral Interbody Fusion (XLIF) in the Thoracic and Thoracolumbar Spine: Technical Report and Early Outcomes.

BACKGROUND: Previous studies have demonstrated the distinct advantages of thoracoscopically assisted spinal fusion compared to traditional open thoracotomy. However, these techniques are limited by a steep learning curve, prolonged operative time, and lack of three-dimensional visualization of the surgical field. OBJECTIVE: The objective of this study was to describe our initial experience with an adaptation of the extreme lateral interbody fusion (XLIF) technique allowing access to the anterior aspect of the thoracic and thoracolumbar spine with specific reference to (1) early pulmonary complications, (2) non-pulmonary complications, and (3) ability of this technique to successfully achieve spinal decompression and fusion at the operative level. METHODS: Clinical and radiographic data were reviewed for the entire perioperative period. A total of 18 patients (72% females; mean age, 56.8 years) underwent a thoracic XLIF procedure for spinal pathologies including disc herniation, fracture, tumor, pseudoarthrosis, and proximal junctional kyphosis. A total of 32 levels were treated, with the majority located at the thoracolumbar junction. Twelve of the procedures were done as part of a combined anterior/posterior surgery. RESULTS: The mean estimated blood loss was 577 ml and the mean length of stay was 12 days. At a mean follow-up of 14 months, all patients except for one (who died of widely metastatic disease) had achieved radiographic evidence of fusion. Two patients developed pulmonary effusions requiring medical intervention. Six patients had seven non-pulmonary complications: incidental durotomy (two), infection (one), instrumentation pullout (one), cardiac arrhythmia (two), and death from metastatic disease (one). CONCLUSIONS: The XLIF technique can be utilized for access to the anterior column of the thoracic and thoracolumbar spine. The advantages of this minimally invasive technique include avoidance of the need for an access surgeon and for lung deflation during surgery as well as excellent visualization of the spinal pathology.

Incidence, diagnosis, and management of sacral fractures following multilevel spinal arthrodesis.

BACKGROUND: Fractures of the sacrum are a rare complication following instrumented spinal fusion, with only 34 cases previously reported in the literature. Previous series have generally been limited to less than five cases. PURPOSE: The purpose of this study is to determine the incidence of sacral fractures caudal to instrumented spinal fusion constructs, identify risk factors for fracture and for failure of conservative management, and describe strategies for surgical treatment of these fractures. STUDY DESIGN: This is a retrospective review. PATIENT SAMPLE: Patients undergoing instrumented posterior spinal arthrodesis between 2002 and 2011 were included in the sample. OUTCOME MEASURES: Clinical and radiographic data from hospital and surgeon records comprise outcome measures. METHODS: Methods include a review of clinical and radiographic data from a prospectively collected patient database recording all adjacent segment fractures during the study period. RESULTS: Twenty-four patients developed sacral fractures caudal to instrumented spinal fusion constructs during the study period. The overall incidence was 6.1% and was significantly greater in fusions greater than four levels (14.5%). The mean time from index surgery to fracture was 4.3 months. Only one fracture was evident on plain radiography at the onset of symptoms. Computed tomography, magnetic resonance imaging, and nuclear scintigraphy can all be used to establish the diagnosis. Eight patients were successfully treated conservatively. The mean time to fracture union was 21 weeks. Anterolisthesis of the fracture greater than 2 mm and kyphotic angulation were significantly associated with failure of conservative management. Surgical intervention included posterior extension of the fusion construct to S2 and the iliac wings with sacroiliac joint fusion. In 10 cases, a combined anterior and posterior approach was used that consisted of either revision anterior lumbar interbody fusion or transsacral posterior lumbar interbody fusion. CONCLUSIONS: Sacral fractures following instrumented posterior spinal fusion are an uncommon complication; that is often unrecognized on plain radiographs. Risk factors include osteoporosis and long spinal fusions. Anterolisthesis and kyphosis of the fracture is associated with failure of conservative management.

Lower preoperative Hounsfield unit measurements are associated with adjacent segment fracture after spinal fusion.

STUDY DESIGN: Retrospective case-control study. OBJECTIVE: To determine the association of Hounsfield unit (HU) measurements with adjacent segment fractures after spinal fusion. SUMMARY OF BACKGROUND DATA: Adjacent segment fracture is a potentially devastating complication after spinal fusion surgery in osteoporotic patient. Recently, a technique for assessing bone mineral density using HU measurements from computed tomography was described and correlated with both dual-energy x-ray absorptiometry-assessed bone mineral density and compressive strength in an osseous model. METHODS: Patients with adjacent segment fractures after spinal fusion were identified from a prospectively collected patient database and matched 1:1 with nonfracture controls on the basis of age, sex, and fusion construct. Minimum follow-up was 6 months. Patients with metabolic bone disease other than osteoporosis or those taking medications known to negatively alter bone strength were excluded. HU assessment was done according to the previously published protocol using the preoperative computed tomography. RESULTS: Twenty patients had complete imaging data and could be matched to nonfracture controls. The groups were well matched with respect to age, sex, body mass index, and number of levels fused. Following the index surgical procedure, the fracture group had more positive sagittal balance than the control group (10.7 cm vs. 9.1 cm). Analysis of HU values at the fracture level showed a significantly lower value in the fracture group than in the controls (145.6 vs. 199.4, P = 0.006). Similarly, global assessment of HU across the thoracic and lumbar spines was significantly lower in the fracture group (139.9 vs. 170.1, P = 0.032). CONCLUSION: HU was significantly lower both locally and globally in the fracture cohort. Because computed tomographic scans are frequently part of preoperative planning for spinal fusion, this information should be incorporated in preoperative planning. Studies to prospectively validate HU as a predictor of adjacent segment fracture risk and to assess the effect of increasing HU preoperatively with medications for osteoporosis are needed. LEVEL OF EVIDENCE: 3.

Operative and nonoperative treatment of cervical disc herniation in National Football League athletes.

BACKGROUND: Limited evidence exists to guide clinical decision making regarding cervical disc herniations in professional athletes playing for the National Football League (NFL) in the United States. PURPOSE: To describe the presentation and treatment outcomes of cervical disc herniations in NFL athletes with a focus on safety and return to sport. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The records of a single NFL team and its consulting physicians were reviewed from 2000 to 2011. Only athletes with magnetic resonance imaging (MRI)-proven disc herniation concordant with the reported symptoms were included. RESULTS: A total of 16 athletes met inclusion criteria. Linemen, linebackers, and defensive backs were the most represented positions (13/16 athletes; 81%). The most common presentation was radiculopathy after a single traumatic event (9/16 athletes; 56%). Three players had transient paresis. Three players underwent one-level anterior cervical discectomy and fusion. These 3 players had failed nonoperative therapy and had evidence of spinal cord compression with signal change on MRI, but only 1 returned to sport. Three players received epidural steroid injections, which provided transient symptomatic relief. Five players were treated nonoperatively and did not return to sport. Two of these 5 athletes had cord compression with signal change and retired rather than undergo surgery. The other 3 were cleared but were released by the team. Eight players were treated nonoperatively and returned to sport. Three of these 8 athletes had evidence of disc material abutting the cord without cord signal change but had a normal examination finding and returned to sport after resolution of their symptoms and repeat MRI that demonstrated no cord compression. Five of the 8 players had evidence of root compression and were treated symptomatically. There were no subsequent traumatic spinal cord injuries at a minimum of 1-year follow-up. CONCLUSION: Data regarding the treatment of this unique population are limited but suggest that NFL athletes can safely return to sport after the treatment of cervical disc herniations. In the treatment algorithm for this study, cord compression with signal change in the cord on MRI was a consistent operative indication. Discs abutting the cord can be treated nonoperatively but do not allow for return to sport until symptoms have improved and repeat imaging demonstrates no cord compression. Isolated nerve root compression has a more favorable prognosis. It can be treated symptomatically and return to sport allowed when symptoms permit.

Management of postoperative spinal infections.

Postoperative surgical site infection (SSI) is a common complication after posterior lumbar spine surgery. This review details an approach to the prevention, diagnosis and treatment of SSIs. Factors contributing to the development of a SSI can be split into three categories: (1) microbiological factors; (2) factors related to the patient and their spinal pathology; and (3) factors relating to the surgical procedure. SSI is most commonly caused by Staphylococcus aureus. The virulence of the organism causing the SSI can affect its presentation. SSI can be prevented by careful adherence to aseptic technique, prophylactic antibiotics, avoiding myonecrosis by frequently releasing retractors and preoperatively optimizing modifiable patient factors. Increasing pain is commonly the only symptom of a SSI and can lead to a delay in diagnosis. C-reactive protein and magnetic resonance imaging can help establish the diagnosis. Treatment requires acquiring intra-operative cultures to guide future antibiotic therapy and surgical debridement of all necrotic tissue. A SSI can usually be adequately treated without removing spinal instrumentation. A multidisciplinary approach to SSIs is important. It is useful to involve an infectious disease specialist and use minimum serial bactericidal titers to enhance the effectiveness of antibiotic therapy. A plastic surgeon should also be involved in those cases of severe infection that require repeat debridement and delayed closure.

Bone tissue composition varies across anatomic sites in the proximal femur and the iliac crest.

The extent to which bone tissue composition varies across anatomic sites in normal or pathologic tissue is largely unknown, although pathologic changes in bone tissue composition are typically assumed to occur throughout the skeleton. Our objective was to compare the composition of normal cortical and trabecular bone tissue across multiple anatomic sites. The composition of cadaveric bone tissue from three anatomic sites was analyzed using Fourier transform infrared imaging: iliac crest (IC), greater trochanter (GT), and subtrochanteric femur (ST). The mean mineral:matrix ratio was 20% greater in the subtrochanteric cortex than in the cortices of the iliac crest (p = 0.004) and the greater trochanter (p = 0.02). There were also trends toward 30% narrower crystallinity distributions in the subtrochanteric cortex than in the greater trochanter (p = 0.10) and 30% wider crystallinity distributions in the subtrochanteric trabeculae than in the greater trochanter (p = 0.054) and the iliac crest (p = 0.11). Thus, the average cortical tissue mineral content and the widths of the distributions of cortical crystal size/perfection differ at the subtrochanteric femur relative to the greater trochanter and the iliac crest. In particular, the cortex of the iliac crest has lower mineral content relative to that of the subtrochanteric femur and may have limited utility as a surrogate for subtrochanteric bone.

Indirect foraminal decompression after lateral transpsoas interbody fusion.

OBJECT: Lateral transpsoas interbody fusion (LTIF) permits anterior column lumbar interbody fusion via a direct lateral approach. The authors sought to answer 3 questions. First, what is the effect of LTIF on lumbar foraminal area? Second, how does interbody cage placement affect intervertebral height? And third, how does the change in foraminal area and cage position correlate with changes in Oswestry Disability Index (ODI) and 12-Item Short Form Health Survey (SF-12) scores? METHODS: Included patients underwent LTIF with or without posterior instrumentation and received preoperative and postoperative CT scans. Disc heights, neural foraminal area between adjacent-level pedicles, and anteroposterior cage position were measured from sagittal CT images. Preoperative and postoperative ODI and SF-12 scores were matched with the change in foraminal area from the clinically most severely affected side for analysis of the relationship between outcomes instruments and change in foraminal area. RESULTS: Average foraminal area increased by 36.2 mm(2), or 35% of the preoperative area (p < 0.01), without statistically significant differences by side, level, or anteroposterior cage position. Preoperative anterior and posterior disc heights measured 6.2 mm and 3.7 mm, respectively, compared with postoperative measurements of 9.8 mm (p < 0.01) and 6.3 mm (p < 0.01), respectively, without significant differences by level or cage position. Despite significant overall improvement in ODI and SF-12 scores, there was no correlation with foraminal area increase. CONCLUSIONS: Average foraminal area increased approximately 35% after cage placement without variation based on cage position. While ODI and SF-12 scores increased significantly, there was no significant association with cage position or foraminal area change, likely attributable to the multifactorial nature of preoperative pain.

Fractures of the sacrum after chemoradiation for rectal carcinoma: incidence, risk factors, and radiographic evaluation.

PURPOSE: Sacral insufficiency fractures after adjuvant radiation for rectal carcinoma can present similarly to recurrent disease. As a complication associated with pelvic radiation, it is important to be aware of the incidence and risk factors associated with sacral fractures in the clinical assessment of these patients. METHODS AND MATERIALS: Between 1998 and 2007, a total of 582 patients with locally advanced rectal carcinoma received adjuvant chemoradiation and surgical excision. Of these, 492 patients had imaging studies available for review. Hospital records and imaging studies from all 492 patients were retrospectively evaluated to identify risk factors associated with developing a sacral insufficiency fracture. RESULTS: With a median follow-up time of 3.5 years, the incidence of sacral fractures was 7.1% (35/492). The 4-year sacral fracture free rate was 0.91. Univariate analysis showed that increasing age (≥60 vs. <60 years), female sex, and history of osteoporosis were significantly associated with shorter time to sacral fracture (P=.01, P=.004, P=.001, respectively). There was no significant difference in the time to sacral fracture for patients based on stage, radiotherapy dose, or chemotherapy regimen. Multivariate analysis showed increasing age (≥60 vs. <60 years, hazard ratio [HR] = 2.50, 95% confidence interval [CI] = 1.22-5.13, P=.01), female sex (HR = 2.64, CI = 1.29-5.38, P=.008), and history of osteoporosis (HR = 3.23, CI = 1.23-8.50, P=.02) were independent risk factors associated with sacral fracture. CONCLUSIONS: Sacral insufficiency fractures after pelvic radiation for rectal carcinoma occur more commonly than previously described. Independent risk factors associated with fracture were osteoporosis, female sex, and age greater than 60 years.

Reduced cortical bone compositional heterogeneity with bisphosphonate treatment in postmenopausal women with intertrochanteric and subtrochanteric fractures.

Reduction of bone turnover with bisphosphonate treatment alters bone mineral and matrix properties. Our objective was to investigate the effect of bisphosphonate treatment on bone tissue properties near fragility fracture sites in the proximal femur in postmenopausal women with osteoporosis. The mineral and collagen properties of corticocancellous biopsies from the proximal femur were compared in bisphosphonate-naive (-BIS, n = 20) and bisphosphonate-treated (+BIS, n = 20, duration 7 ± 5 years) patients with intertrochanteric (IT) and subtrochanteric (ST) fractures using Fourier transform infrared imaging (FTIRI). The mean values of the FTIRI parameter distributions were similar across groups, but the widths of the parameter distributions tended to be reduced in the +BIS group relative to the -BIS group. Specifically, the widths of the cortical collagen maturity and crystallinity were reduced in the +BIS group relative to those of the -BIS group by 28% (+BIS 0.45 ± 0.18 versus -BIS 0.63 ± 0.28, p = 0.03) and 17% (+BIS 0.087 ± 0.012 versus -BIS 0.104 ± 0.036, p = 0.05), respectively. When the tissue properties were examined as a function of fracture morphology within the +BIS group, the FTIR parameters were generally similar regardless of fracture morphology. However, the cortical mineral:matrix ratio was 8% greater in tissue from patients with atypical ST fractures (n = 6) than that of patients with typical (IT or spiral ST) fractures (n = 14) (Atypical 5.6 ± 0.3 versus Typical 5.2 ± 0.5, p = 0.03). Thus, although the mean values of the FTIR properties were similar in both groups, the tissue in bisphosphonate-treated patients had a more uniform composition than that of bisphosphonate-naive patients. The observed reductions in mineral and matrix heterogeneity may diminish tissue-level toughening mechanisms.

Factors influencing segmental lumbar lordosis after lateral transpsoas interbody fusion.

OBJECTIVE: Although contributions to sagittal alignment have been characterized for anterior, posterior and transforaminal lumbar interbody fusion, sagittal alignment after lateral transpsoas interbody fusion (LTIF) has not yet been characterized. This study examined the ability of LTIF to restore lumbar lordosis and identified factors associated with change in sagittal alignment. METHODS: Twenty-nine patients and 67 levels were studied. Segmental lordosis, anterior-posterior cage position, and cage obliquity were measured on preoperative and postoperative radiographs and CT scans. Change in sagittal alignment was analyzed with respect to demographic information and measures of cage position and obliquity to identify factors associated with segmental alignment change. RESULTS: Mean lordosis increased 3.7° at instrumented segments, increasing from 4.1° preoperatively to 7.8° postoperatively. Although increases at each level were significant, there were no significant differences between levels. Lordosis increase was inversely-associated with preoperative lordosis; levels with the least preoperative lordosis gained the most lordosis. Cage obliquity and height were not significantly associated with lordosis change. Anterior cage placement resulted in the largest lordosis gain (+7.4°/level) while posterior placement was prokyphotic (-1.2°/level). There were no significant associations with age, sex or body mass index. CONCLUSION: Anteroposterior cage placement is an important intraoperative determinant of postoperative alignment; anterior placement results in greater lordosis while middle/posterior placement has a minimal effect on sagittal alignment.

Salvage of lumbar pseudarthrosis with customized large-diameter pedicle screws: report of two cases.

STUDY DESIGN: A report of two cases using custom-manufactured pedicle screws for revision spinal arthrodesis for pseudarthrosis in the setting of widely dilated pedicle screw tracts. OBJECTIVE: To present surgical outcomes of a previously unreported treatment for pseudarthrosis with widely dilated pedicle screw tracts. SUMMARY OF BACKGROUND DATA: Techniques for revision of lumbar pseudarthrosis with severe screw loosening and widely dilated pedicle screw tracts represent a challenging clinical scenario. If stable fixation cannot be achieved, fixation may fail or adjacent normal levels may need to be included in the construct. METHODS: Two patients presenting with painful pseudarthrosis after lumbar spinal fusion and instrumentation loosening with widely dilated pedicle screw tracts were treated with revision anterior and posterior spinal fusion using custom-manufactured large-diameter pedicle screws. RESULTS: In both cases, the custom-manufactured pedicle screws achieved excellent purchase in the dilated pedicle screw tract. Both patients went on to solid fusion at 1 year after surgery. CONCLUSION: This is a previously unreported technique for revision spinal fusion in the setting of loose instrumentation with widely dilated pedicle screw tracts.

Transforaminal Thoracic Interbody Fusion (TTIF) for Treatment of a Chronic Chance Injury.

Multiple anterior and posterior approaches to the thoracic disc space have been reported. However, we are not aware of any previous reports describing a transforaminal approach for thoracic disc release and interbody cage placement. In this case report, we describe a method to perform transforaminal thoracic interbody fusion (TTIF), which is an adaptation of an established lumbar fusion technique (transforaminal lumbar interbody fusion). Key differences between the two procedures are discussed. A 24-year-old woman presented after sustaining a T11-12 Chance fracture that had been treated in a brace. She had severe, debilitating pain and a rigid segmental kyphotic deformity of 38°. The patient was treated 3 months post-injury with T10-L1 fusion with anterior release and interbody fusion with cage placement at T11-12. Anterior column release and fusion were performed via a transforaminal approach. The patient had anatomic reduction of deformity, solid arthrodesis, and relief of pain at 1-year follow-up. The TTIF approach permits access to the anterior column of the thoracic spine for the purpose of reduction of deformity and interbody fusion with reduced morbidity compared to anterior-posterior surgery.

Obesity increases the risk of recurrent herniated nucleus pulposus after lumbar microdiscectomy.

BACKGROUND CONTEXT: Recurrent herniation of the nucleus pulposus (HNP) frequently causes poor outcomes after lumbar discectomy. The relationship between obesity and recurrent HNP has not previously been reported. PURPOSE: The purpose of this study was to investigate the association of obesity with recurrent HNP after lumbar microdiscectomy. STUDY DESIGN: Retrospective Cohort. PATIENT SAMPLE: We reviewed all cases of one- or two-level lumbar microdiscectomy from L2-S1 performed by a single surgeon with a minimum follow-up of 6 months. OUTCOME MEASURES: The primary clinical outcomes were evidence of recurrent HNP on magnetic resonance imaging (MRI) and need for repeat surgery. METHODS: All patients with recurrent radicular pain or new neurological deficits underwent a postoperative MRI scan. Recurrent HNP was defined as a HNP at the same side and same level as the index procedure. RESULTS: Seventy-five patients were included in the study. The average body mass index (BMI) was 27.6+/-4.6. Thirty-two patients received an MRI scan. The time from operation to repeat MRI scan varied widely (3 days to 15 months). Eight patients (10.7%) had recurrent HNP. Four patients had persistent symptoms requiring reoperation (5.3%). The mean BMI of patients with recurrent HNP was significantly higher than that of those without recurrence (33.6+/-5.1 vs. 26.9+/-3.9, p<.001). In univariate analysis, obese patients (BMI >or=30) were 12 times more likely to have recurrent HNP than nonobese patients (odds ratio [OR]: 12.46, 95% confidence interval [CI]: 2.25-69.90). Obese patients were 30 times more likely to require reoperation (OR: 32.81, 95% CI: 1.67-642.70). Age, sex, smoking, and being a manual laborer were not significantly associated with recurrent HNP. A logistic regression analysis supported the findings of the univariate analysis. In a survival analysis using a Cox proportional hazards model, the hazard ratio of recurrent HNP for obese patients was 17 (OR: 17.08, 95% CI: 2.85-102.30, p=.002). CONCLUSIONS: Obesity was a strong and independent predictor of recurrent HNP after lumbar microdiscectomy. Surgeons should incorporate weight loss counseling into their preoperative discussions with patients.