Giant cell tumor of a lumbar vertebra in a 7-year-old child: a case report.

STUDY DESIGN: This case provides a rare occurrence of a giant cell tumor (GCT) in posterior elements of a lumbar vertebra in a 7-year-old child with successful outcome after surgical excision and regular follow-ups. OBJECTIVE: To present a unique case report of a pediatric GCT in the vertebral column and results. SUMMARY OF BACKGROUND DATA: GCT is a rare bone tumor seen in 3% to 5% of primary bone neoplasm. Approximately 7% of GCTs are found in the vertebral column. GCT of the spine is found in only 5% to 7% of cases and can occur in any region of the spine but are believed to be predominantly in the sacrum. Despite its benign nature, expansion in a confined space makes early detection of spinal GCTs important to prevent occurrence of compressive myelopathy/radiculopathy. The presence of a GCT in a child younger than 10 years of age, in posterior elements of a lumbar vertebral body, has not been reported earlier. METHODS: On the basis of the clinical history, radiograph of the thoracolumbar spine, computed tomography of lumbar spine, and magnetic resonance imaging, a preliminary diagnosis of osteoblastoma was made. RESULTS: The patient presented with a lytic lesion with involvement of posterior elements, 1 side the pedicle extending into the body of a lumbar vertebra (L3) and had extension into the paraspinal muscles. Intraoperative exploration and frozen section showed the presence of a typical histologic picture of a GCT. Ipsilateral pedicle, posterior elements, and the superior articular facet were excised. En bloc resection was found not to be feasible due to the friable nature of the tumor and involvement of the soft tissues. In addition, fusion was avoided with consideration of the young age of the patient. CONCLUSIONS: The patient has been free of any recurrence as of his last follow-up visit.

CT based bone mineral density as a predictor of proximal junctional fractures.

Background: Proximal junctional fractures (PJFr) can be a catastrophic complication associated with adult spinal deformity surgery. Osteoporosis can be a major risk factor for the cause of PJFr. Recent studies suggest using surrogate computed tomography (CT) scans in place of spinal dual-energy x-ray absorptiometry (DEXA) scores for bone mineral density (BMD). Investigate the feasibility of using preoperative CT based bone mineral density at upper instrumented vertebrae (UIV) and one level proximally (UIV+1) and distally (UIV-1) to predict the possibility of PJFr risk. Methods: Retrospective two-academic center case-controlled study, reviewed consecutive adult spinal deformity surgeries; included constructs encompassing at least five fusion levels and fusions to pelvis. Examined demographic, surgical, and radiographic data preoperatively, postoperatively, and final follow-up. Formed groups based on type of proximal junctional deformity (PJD): Control (no PJD), proximal junctional kyphosis (PJK) and PJFr. Preoperative CT BMD values measured in Hounsfield units (HU) for sagittal and axial planes at UIV, UIV+1, and UIV-1 and compared between groups. Results: N=92 patients. Preoperative CT scan BMD values were significantly lower in PJFr vs. control at: UIV+1 in sagittal (p=0.007), axial (p=0.02) planes; UIV sagittal (p=0.04) and axial (p=0.03) planes; and UIV-1 sagittal (p=0.05) plane. Similarly, lower CT scan BMD values noted in PJFr vs. PJK at: UIV+1 in sagittal (p=0.04) and axial (p=0.03) planes. Trend seen with lower CT scan BMD values at UIV+1 level in PJFr vs. PJK in sagittal (p=0.12) and axial (p=0.10) planes. Preoperative global sagittal imbalance measurements significantly lower in control, but comparable between PJK and PJFr. Conclusions: Higher preoperative global sagittal imbalance with lower preoperative CT BMD values at UIV and UIV+1 vertebral body may increase the risk of proximal junctional fractures after adult spine deformity surgery. Proximal junctional hooks may supplement the pathogenesis. Readers should note the small sample size.Level of Evidence: 3.

Complications associated with thoracic pedicle screws in spinal deformity.

Thoracic pedicle screws have superior anchoring strength compared with other available fixation techniques. However, these are not universally accepted in many developing countries because of the concerns regarding safety and complications. In addition, there is evidence that pedicle morphology is unique in Chinese patients. The goal of this study was to analyze the complications seen at our institution, while using thoracic pedicle screws for the treatment of thoracic deformity, and to determine the safety of our techniques for the treatment of thoracic deformity in a Chinese population. From 1998 to 2005, there were 208 thoracic deformity patients treated at our institution, 70 of whom were male and 138 were female. Their age ranged from 11 to 55 years (mean of 14.9 years). All of them underwent corrective deformity surgery using posterior pedicle screw systems and follow-up was available for at least 3 years. Etiologic diagnoses included adolescent idiopathic scoliosis in 119 patients, congenital kyphoscoliosis in 38, adult scoliosis in 37 and undetermined in 14. Screw positions were evaluated using intraoperative and postoperative radiographs and a CT scan was performed when a concern for screw malposition was present. All radiographic evaluations were carried out in a double-blinded fashion. A total of 1,123 thoracic pedicle screws were inserted (5.4 thoracic screws/patient). The deformity correction rate was 81, 65 and 62% for idiopathic, congenital and adult scoliosis patients, respectively. The overall complication rate was 16.5% at the final follow-up. Complication rates directly and indirectly related to pedicle screws were 7.2 and 9.3%, respectively. There were no significant screw-related neurologic or visceral complications that adversely affected long-term results. The complications seen with thoracic pedicle screws in a Chinese population were similar to other populations and could be utilized safely for the treatment of thoracic deformity in this population.

Nerve Root Sedimentation Sign: Can It Predict the Success for Surgical Intervention in Patients With Symptomatic Lumbar Spinal Stenosis?

INTRODUCTION:  The use of interspinous process devices are less invasive surgical methods designed to manage mild to moderate lumbar spinal stenosis symptoms. Symptomatic relief may not be seen in all patients undergoing this procedure. Magnetic resonance imaging (MRI) parameters have been used to predict the success of clinical outcomes in patients with symptomatic lumbar spinal stenosis for decompressive surgeries. The purpose of this study was to determine the feasibility of using nerve root sedimentation sign to predict mid- to long-term clinical outcomes of patients treated with interspinous spacers for lumbar spinal stenosis. METHODS: This was a retrospective study using prospective multicenter Food and Drug Administration Investigational Device Exemption (FDA IDE) trial (Superion™ and X-STOP®) data. Inclusion criteria were patients treated with interspinous spacers, aged 45 or older with lumbar spinal stenosis at one or more contiguous levels from L1 to L5 and symptoms of neurogenic claudication. Preoperative axial T2 weighted MRI images were used to determine nerve root sedimentation sign. Preoperative, six-week, one- and two-year postoperative clinical outcomes were measured using Oswestry Disability Index (ODI) scores. Clinical outcomes were compared between positive and negative nerve root sedimentation sign groups; p ≤0.05 was considered significant. RESULTS: This study included n=374 patients; 40 excluded; 334 included (113=positive nerve root sedimentation sign (NRSS) (34%) and 221=negative NRSS (66%)). At six weeks, significant postoperative ODI correction was noted in both groups (p<0.001). No significant differences in ODI scores were identified between groups. A subgroup analysis with MRI image quality grade 3 and certainty determination grade 5, six-week postoperative ODI correction was significant in both groups. Six-week, one- and two-year postoperative ODI scores were greater by 6 points in the positive nerve root sedimentation sign group compared to the negative nerve root sedimentation sign group. CONCLUSIONS:  Although satisfactory postoperative improvement occurred in both groups, there were statistically significant differences noted in certain sub-categories. The subgroup analysis indicated MRI image quality and nerve root sedimentation sign certainty of determination may be factors that may aid with planning the surgical management of lumbar spinal stenosis.

The Effect of Kyphoplasty on Mortality in Symptomatic Vertebral Compression Fractures: A Review.

BACKGROUND: Vertebral compression fractures (VCFs) are common comorbidities encountered in the elderly, and they are on the rise. Kyphoplasty may be superior in VCF management compared with conservative management. A comprehensive review of literature was conducted, focusing on the effect of kyphoplasty on mortality and overall survivorship in patients with a diagnosis of symptomatic VCFs. METHODS: A comprehensive literature search was conducted to find recently published literature on kyphoplasty effects on mortality using the following keywords: "kyphoplasty," "mortality," "morbidity," "vertebral compression fractures," and "survivorship." We only included articles that listed one of their primary or secondary outcomes as morbidity and mortality after a kyphoplasty procedure in VCF patients. RESULTS: Of 27 articles, only 6 articles met the inclusion criteria. Studies have reported that surgical procedures have decreased the mortality rate in symptomatic VCF patients. Four studies concluded that the mortality rate was lower after kyphoplasty compared with vertebroplasty and nonoperative treatments. One study reported there was no significant difference between kyphoplasty and nonoperative management. One study summarized that the mortality rate was not significantly different between kyphoplasty and vertebroplasty. CONCLUSIONS: Multicenter prospective and randomized control studies are required to fully evaluate the decreasing trend of mortality rates after a kyphoplasty procedure.

Assessment of Coronal Spinal Alignment for Adult Spine Deformity Cases After Intraoperative T Square Shaped Use.

STUDY DESIGN: Retrospectively reviewed surgeries between 2011 and 2015 of patients who underwent posterior spinal deformity instrumentation with constructs involving fusions to pelvis and encompassing at least five levels. OBJECTIVE: Measure the radiographic outcomes of coronal malalignment (CM) after use of an intraoperative T square shaped instrument in posterior spinal deformity surgeries with at least five levels of fusion and extension to pelvis. BACKGROUND: Neuromuscular children found to benefit from intraoperative T square technique to help achieve proper coronal spinal balance with extensive fusions. This intraoperative technique used in our posterior spine deformity instrumentation surgeries with the aforementioned parameters. METHODS: There were 50 patients: n = 16 with intraoperative T square and n = 34 no-T square shaped device. Subgroups divided based on greater than 20 mm displacement and greater than 40 mm displacement of the C7 plumb line to the central sacral vertical line on either side in preoperative radiographs. We analyzed the demographics and the pre- and postoperative radiographic parameters of standing films: standing CM (displacement of C7 plumb line to central sacral vertical line), and major coronal Cobb angles in total sample and subgroups and compared T square shaped device with no-T square shaped device use by analysis of variance. A p value ≤.05 is statistically significant. RESULTS: In the total sample, though postoperative CM mean was not statistically different, we observed greater CM corrections in patients where a T square shaped device was used (70%) versus no-T square shaped device used (18%). In >20 mm and >40 mm subgroups, the postoperative mean CM values were statistically lower for the patients where a T square shaped device was used, p = .016 and p = .003, respectively. Cobb corrections were statistically higher for T square shaped device use in both >20 mm and >40 mm subgroups, 68%, respectively. CONCLUSION: The intraoperative T square shaped device technique had a positive effect on the amount of spine coronal malalignment correction after its use and for lumbar and thoracic coronal Cobb angles. LEVEL OF EVIDENCE: Level III.

Magnetically controlled growing rods for scoliosis surgery.

INTRODUCTION: Early onset scoliosis can be both a disfiguring as well as a life threatening condition. When more conservative treatments fail, pediatric spinal surgeons are forced to consider operative interventions. Traditionally, these interventions have involved the insertion of a variety of implants into the patient with a limited number of anchor points controlling the spine. In the past, these pediatric patients have had multiple surgeries for elective lengthening of these devices to facilitate their growth while attempting to control the scoliosis. These patients often experience a physical and emotional toll from their multiple repeated surgeries. Growing spine techniques have also had a noted high complication rate due to implant dislodgement and infections. Recently, the development of non-invasively, self-lengthening growing rods has occurred. These devices have the potential to allow for the devices to be lengthened magnetically in a conscious patient in the surgeon's office. Areas covered: This review summarized previously published articles in the English literature using a key word search in PubMed for: 'magnetically controlled growing rods', 'Magec rods', 'magnetic growing rods' and 'growing rods'. Expert commentary: Magnetically controlled growing rods have an advantage over growing rods in lengthening the growing spine in the absence of repetitive surgeries.

Surgeon Reliability for the Assessment of Lumbar Spinal Stenosis on MRI: The Impact of Surgeon Experience.

BACKGROUND: Treating surgeon's visual assessment of axial MRI images to ascertain the degree of stenosis has a critical impact on surgical decision-making. The purpose of this study was to prospectively analyze the impact of surgeon experience on inter-observer and intra-observer reliability of assessing severity of spinal stenosis on MRIs by spine surgeons directly involved in surgical decision-making. METHODS: Seven fellowship trained spine surgeons reviewed MRI studies of 30 symptomatic patients with lumbar stenosis and graded the stenosis in the central canal, the lateral recess and the foramen at T12-L1 to L5-S1 as none, mild, moderate or severe. No specific instructions were provided to what constituted mild, moderate, or severe stenosis. Two surgeons were "senior" (>fifteen years of practice experience); two were "intermediate" (>four years of practice experience), and three "junior" (< one year of practice experience). The concordance correlation coefficient (CCC) was calculated to assess inter-observer reliability. Seven MRI studies were duplicated and randomly re-read to evaluate inter-observer reliability. RESULTS: Surgeon experience was found to be a strong predictor of inter-observer reliability. Senior inter-observer reliability was significantly higher assessing central(p<0.001), foraminal p=0.005 and lateral p=0.001 than "junior" group.Senior group also showed significantly higher inter-observer reliability that intermediate group assessing foraminal stenosis (p=0.036). In intra-observer reliability the results were contrary to that found in inter-observer reliability. CONCLUSION: Inter-observer reliability of assessing stenosis on MRIs increases with surgeon experience. Lower intra-observer reliability values among the senior group, although not clearly explained, may be due to the small number of MRIs evaluated and quality of MRI images.Level of evidence: Level 3.

Comparison of Surgeon Rating of Severity of Stenosis Using Magnetic Resonance Imaging, Dural Cross-Sectional Area, and Functional Outcome Scores.

OBJECTIVE: To determine the relationship between the severity of stenosis graded using both surgeons' visual assessment of spinal stenosis as well as measurement of dural cross-sectional area on magnetic resonance imaging (MRI), with the patient's disability. METHODS: Seven fellowship-trained spine surgeons reviewed MRI studies retrospectively of 30 symptomatic consecutive patients with lumbar stenosis and graded stenosis in the central canal, the lateral recess, and the foramen at T12-L1 to L5-S1 as none, mild, moderate, or severe. Dural cross-sectional area was measured at each level from T12-L1 to L5-S1. All patients completed the questionnaires for Oswestry Disability Index (ODI), Short Form 36 (SF-36), and recorded Visual Analog Scale scores for leg and back pain, and symptom severity scale of the Zurich claudication questionnaire. RESULTS: There was positive correlation between the right leg pain Visual Analog Scale score and the mean surgeon grades for central and lateral recess stenosis at L4-L5 and lateral recess stenosis at L5-S1. Except for a positive correlation between role physical score and surgeon grade for lateral recess stenosis at L5-S1, we found no correlation between the surgeons' grading of stenosis at any level with the ODI or SF-36. We found no correlation between the dural cross-sectional area with the ODI or SF-36. We did not find any correlation between the Zurich symptom severity scale and surgeons' grading of stenosis at any level. CONCLUSIONS: Although surgeons rely on visual assessment of the severity of stenosis while making surgical decisions, we found that objective and subjective imaging parameters to grade severity of stenosis did not consistently indicate the patient's disability level.

Vertebral artery injury associated with blunt cervical spine trauma: a multivariate regression analysis.

STUDY DESIGN: Retrospective analysis of prospective registry data. OBJECTIVE: To determine the patient characteristics, risk factors, and fracture patterns associated with vertebral artery injury (VAI) in patients with blunt cervical spine injury. SUMMARY OF BACKGROUND DATA: VAI associated with cervical spine trauma has the potential for catastrophical clinical sequelae. The patterns of cervical spine injury and patient characteristics associated with VAI remain to be determined. METHODS: A retrospective review of prospectively collected data from the American College of Surgeons trauma registries at 3 level-1 trauma centers identified all patients with a cervical spine injury on multidetector computed tomographic scan during a 3-year period (January 1, 2007, to January 1, 2010). Fracture pattern and patient characteristics were recorded. Logistic multivariate regression analysis of independent predictors for VAI and subgroup analysis of neurological events related to VAI was performed. RESULTS: Twenty-one percent of 1204 patients with cervical injuries (n = 253) underwent screening for VAI by multidetector computed tomography angiogram. VAI was diagnosed in 17% (42 of 253), unilateral in 15% (38 of 253), and bilateral in 1.6% (4 of 253) and was associated with a lower Glasgow coma scale (P < 0.001), a higher injury severity score (P < 0.01), and a higher mortality (P < 0.001). VAI was associated with ankylosing spondylitis/diffuse idiopathic skeletal hyperosteosis (crude odds ratio [OR] = 8.04; 95% confidence interval [CI], 1.30-49.68; P = 0.034), and occipitocervical dissociation (P < 0.001) by univariate analysis and fracture displacement into the transverse foramen 1 mm or more (adjusted OR = 3.29; 95% CI, 1.15-9.41; P = 0.026), and basilar skull fracture (adjusted OR = 4.25; 95% CI, 1.25-14.47; P= 0.021), by multivariate regression model. Subgroup analyses of neurological events secondary to VAI occurred in 14% (6 of 42) and the stroke-related mortality rate was 4.8% (2 of 42). Neurological events were associated with male sex (P = 0.024), facet subluxation/dislocation (crude OR = 9.00; 95% CI, 1.51-53.74; P = 0.004) and the diagnosis of ankylosing spondylitis/diffuse idiopathic skeletal hyperosteosis (OR = 40.67; 95% CI, 5.27-313.96; P < 0.001). CONCLUSION: VAI associated with blunt cervical spine injury is a marker for more severely injured patients. High-risk patients with basilar skull fractures, occipitocervical dissociation, fracture displacement into the transverse foramen more than 1 mm, ankylosing spondylitis/diffuse idiopathic skeletal hyperosteosis, and facet subluxation/dislocation deserve focused consideration for VAI screening.

Bioabsorbable anterior cervical plate fixation for single-level degenerative disorders: early clinical and radiographic experience.

BACKGROUND CONTEXT: Increased fusion rates have been reported with the addition of an anterior cervical plate (ACP) to anterior cervical discectomy and fusion (ACDF). Bioabsorbable implants have become increasingly used in orthopedic and spine surgical procedures. There are limited data regarding the outcomes of bioabsorbable ACP (bACP) with ACDF. PURPOSE: To compare the clinical and radiographic outcomes of patients undergoing ACDF for single-level degenerative disorders with a bACP versus a conventional metal ACP (mACP). STUDY DESIGN: Retrospective comparative cohort study. PATIENT SAMPLE: Thirty-one patients undergoing ACDF for a single-level degenerative disorder (ie, disc herniation or spondylotic neural compression). OUTCOME MEASURES: Incidence of early (within 2 weeks) complications, postoperative sagittal alignment, Odom's criteria, and pseudarthrosis rate. METHODS: The authors retrospectively reviewed the results of a consecutive series of patients undergoing ACDF for symptomatic single-level disc herniation or spondylotic neural compression with either a bACP or an mACP over a 3-year period. Operative notes, clinical charts, and radiographs were analyzed. Radiographic outcomes were assessed for intersegmental alignment, graft subsidence, fusion rate, prevertebral soft-tissue shadow, and graft containment. Clinical outcome was evaluated by Odom's criteria. RESULTS: Fourteen patients underwent ACDF with a bACP and 15 with an mACP. Radiographic outcomes at the most recent follow-up demonstrated pseudarthrosis in 4 of 14 patients (29%) in the bACP group and 0 of 15 patients in the mACP group. Graft extrusion and anterior displacement was present in three of four pseudarthroses (75%). Comparing preoperative and final radiographs, cervical lordosis was maintained at the operative segment in only 3 of 14 bACP patients (21%) compared with 8 of 15 patients (53%) in the mACP group. The mean Cobb angle was 2.4°±1.9° lordosis in the mACP group and -2.7°±2.5° kyphosis in the bACP group (p=.12). In the mACP group, 14 of 15 patients had good or excellent results. In the bACP group, only 7 of 14 patients had good or excellent results. CONCLUSIONS: Bioabsorbable ACP fixation was associated with a high rate of graft extrusion and early loss of intersegmental cervical alignment. Inferior clinical outcomes were observed in patients in the bACP group compared with the mACP group. Based on these findings, continued use of the bACP used in this study cannot be recommended.

Location of the transverse foramen in the subaxial cervical spine in a young asymptomatic population.

STUDY DESIGN: Computerized tomography of the subaxial cervical spine in 98 young, asymptomatic North American volunteers. OBJECTIVE: To provide normative data on subaxial transverse foramen dimensions and location in relation to surgical landmarks routinely used during operative intervention in the anterior cervical spine. SUMMARY OF BACKGROUND DATA: Vertebral artery injury during anterior cervical spinal surgery is a rare but potentially catastrophic injury. There have been no prior studies in a large group of young, asymptomatic subjects without pathology and where the age, weight, and gender are known. There are no published computerized tomography data evaluating distances between the tip of the uncovertebral joint and the medial margin of the uncovertebral joint, 2 commonly used surgical landmarks. METHODS: Axial and reconstructed coronal computerized tomography images of cervical vertebrae from C3 to C7 in 98 asymptomatic young volunteers were analyzed to measure interforaminal distance, transverse foramen distance from anterior and posterior vertebral body margins, transverse foramen dimensions, and transverse foramen medial margin distance from the uncus tip and medial margin. RESULTS: All measurements were significantly different between males and females, with smaller female dimensions. Interforaminal distance gradually increased from C3 to C7. Transverse foramen anterior margin in relation to the anterior vertebral body was significantly more posterior at C7 compared with the C3-C6 levels. Transverse foramen posterior margin in relation to the vertebral body posterior margin gradually moved anteriorly from C3 to C6 and then posterior again at C7. The vertebral uncus tip and medial margin in relation to the medial transverse foramen averaged 2.8 mm and 5.7 mm for males and 2.7 mm and 5.3 mm for females from C3 to C6. CONCLUSION.: Useful morphometric data are provided that may assist the operating surgeon to avoid vertebral artery injury during anterior surgical approaches to the cervical spine. The medial margin of the uncovertebral joint may be the safest landmark to avoid vertebral artery injury during anterior cervical disc surgery. The vertebral artery is at increased risk of injury during neural decompression at more cephalad levels.

Femoroacetabular impingement in adolescents and young adults.

Femoroacetabular impingement (FAI) is a recently described hip disorder resulting from an abnormal morphology between the proximal femur and acetabulum (socket). It is now recognized as a cause of hip pain in adolescents and young adults, and research has shown that it may also lead to early degenerative changes and osteoarthritis. Femoroacetabular impingement as a cause of precocious hip arthrosis was originally described by Ganz et al. in 2001, and a quick literature search on this topic will confirm that it has become a topic of cutting edge research within the orthopaedic community. The abnormal morphology in FAI results in increased hip contact forces with hip motion, especially flexion. This results in abnormal contact that can lead to acetabular labral tears and cartilaginous injury. Early diagnosis and treatment may possibly delay the future onset of hip arthritis. Although the precise cause of FAI is not well understood, the condition has become increasingly recognized as a cause of hip pain in active adolescents and young adults. The purpose of this article is to outline the history, physical examination and radiographic findings, and current conservative and surgical treatment modalities for FAI.

The effect of platelet-rich plasma and bone marrow on murine posterolateral lumbar spine arthrodesis with bone morphogenetic protein.

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has had limited success in stimulating osteogenesis at the site of posterolateral lumbar spine arthrodesis when used at the currently approved human dose for anterior lumbar interbody arthrodesis. The objective of the present study was to investigate the effect of co-administration of fresh harvested autologous bone marrow aspirate and platelet-rich plasma on rhBMP-2-mediated in vivo murine posterolateral lumbar spine arthrodesis. METHODS: Forty adult male mice underwent posterolateral intertransverse process arthrodesis from L4 to L6. In three experimental groups, a collagen sponge was placed on each side, overlaying the decorticated transverse processes. Each collagen sponge was presoaked for fifteen minutes with 31 microg of rhBMP-2 in a 100-microL solution containing either saline solution (n = 10), platelet-rich plasma (n = 10), or donor bone-marrow cells (n = 10). Control mice underwent decortication alone (n = 10). The lumbar spine was harvested four weeks after surgery, and spinal fusion was evaluated on the basis of radiographs, computed tomography, and histological analysis. RESULTS: Control mice showed no evidence of spinal fusion. The rate of fusion was radiographically and histologically similar in all three experimental groups. The area, volume, and density of the fusion mass were significantly greater (p < 0.05) for the group treated with rhBMP-2 and bone marrow as compared with the group treated with rhBMP-2 alone. The group treated with rhBMP-2 and platelet-rich plasma had intermediate fusion area and density. Histologically, the spines treated with rhBMP-2 alone consistently showed the presence of cortical bone between the two transverse processes but fewer trabeculae within the fusion mass; bone marrow co-augmentation resulted in more trabeculae within the fusion mass and a thicker cortical perimeter. CONCLUSIONS: The present study quantitatively confirmed a synergistic effect of bone marrow cells when added to rhBMP-2 in an in vivo mouse posterolateral lumbar spine fusion model. The volume, area, and density of the fusion mass were significantly increased by augmentation with bone marrow cells.

Posterior atlantoaxial dislocation without odontoid fracture.

We report a case of posterior atlantoaxial dislocation without a fracture of the odontoid in a 35-year-old woman. There have been nine reported cases of similar injury in the English literature. The integrity of the transverse ligament following posterior atlantoaxial dislocations has not been well documented in these reports. In the present case, MRI revealed an intact transverse ligament, which probably contributed to the stability of the C1-C2 complex following closed reduction.

Role of transarticular screw fixation in tuberculous atlanto-axial instability.

Prospective study of 27 consecutive cases of tuberculous atlanto-axial instability operated between 1998 and 2003. Early surgical stabilization of tuberculous atlanto-axial instability has gained popularity. This is largely due to success of chemotherapy in rapid control of infection. Although selective atlanto-axial fusion techniques are advocated in other indications, their role in tuberculosis remains confined to atlanto-axial wiring techniques that are mechanically unsound. The role of three-point rigid fixation using trans-articular screws (TAS) remains unclear. The objectives of this study are: (1) To define the role of trans-articular screws in tuberculous atlanto-axial instability based on radiological criteria. (2) To attempt to separate patients that can be treated by selective atlanto-axial fixation as against the standard occipito-cervical fusion (OCF). (3) Compare the clinical and radiological outcome parameters between the two groups. Twenty-seven consecutive patients of tuberculous atlanto-axial instability were operated between 1998 and 2003. The pattern of articular surface destruction and the reducibility of the atlanto-axial complex were assessed on plain radiographs and MRI. The reducibility of the C1-C2 joint was graded as reducible, partially reducible and irreducible. Pattern of the C1-C2 articular mass destruction was grouped as minimal, moderate and severe. The patients were divided into two surgical groups based on radiological findings and were treated with TAS (n=11) and OCF (n=16) fusion. The three-point fixation provided by the TAS allowed early brace free mobilization by 3 months with fusion rate of 100%. Fusion occurred in 83.16% in the OCF group. Implant failure occurred in two patients who underwent OCF. The patient satisfaction rate in the TAS group and the OCF group was 90.90 and 62.50%, respectively. Results in 27 consecutive patients demonstrate improved patient fusion and satisfaction rates in the TAS group. Judicious selection of patients for TAS fixation is possible with relatively few complications in tuberculosis of the atlanto-axial complex. This, however, requires a thorough understanding of the MRI pattern of involvement of the atlanto-axial complex that is difficult in non-endemic areas.

Epidural varix at the cervicothoracic junction: unusual cause of quadriplegia: a case report.

STUDY DESIGN: A case report describing an unusual incident of quadriplegia in a young adult male caused by an epidural varix at the cervicothoracic junction. OBJECTIVE: To report an unusual case of quadriplegia caused by an epidural varix at the cervicothoracic junction. SUMMARY OF BACKGROUND DATA: Epidural varices are dilated tortuous elongated veins inside the central canal. In degenerative spinal stenosis, these varices are a result of venous stagnation and contribute to the pathogenesis of radicular pain. In the absence of stenosis, primary varicosities develop as a result of dynamic obstruction to venous outflow during spinal movements. A primary epidural varix can produce neurologic deficit similar to a space occupying lesion within the spinal canal. The myeloradiculopathy is of a slow progressive nature. MATERIAL AND METHODS: A young man presented with an acute onset flaccid quadriplegia in the absence of significant trauma. Magnetic resonance imaging revealed an extradural space occupying lesion at the cervicothoracic junction that was diagnosed as an isolated epidural varix during surgery. RESULTS: No neurologic recovery occurred. Postoperative magnetic resonance imaging revealed a syrinx in the cervicothoracic cord. CONCLUSION: In the absence of other precipitating factors, the cord injury was attributed to the epidural varix. A temporary impedance to the venous outflow with the increase in the venous pressure has been hypothesized as the mechanism of cord injury.