Hospital cost analysis of neuromuscular scoliosis surgery.

STUDY DESIGN: A retrospective review of 74 consecutive, surgical patients with neuromuscular scoliosis (NMS). OBJECTIVE: This study evaluates the distribution of hospital and operating room costs incurred during surgical correction of NMS. BACKGROUND DATA: Recent studies have demonstrated that surgical treatment improves both medical outcomes and the quality of life in patients with progressive NMS. Characterization of the costs incurred at the time of surgery and hospitalization will facilitate the identification of opportunities for cost reduction. METHODS: Demographic data collected included gender, age, preoperative height, weight, and BMI. Major coronal curvatures and T5-T12 kyphosis were assessed from radiographs. Construct type and number of screws, hooks, and wires implanted were recorded. Surgical costs were calculated based on cost of surgical correction, hospital stay, and postoperative care. RESULTS: Mean age was 15.8 ± 7.3 years; 57% were male. Comorbidities included cerebral palsy (28%) and familial dysautonomia (14%). The mean preoperative major curve magnitude was 60°; minor curve magnitude was 33°. Posterior approach (76%) and pedicle screws (75%) were predominantly utilized. The average length of hospitalization was 8 days (range: 3 to 47). There were six major complications (8%). The total surgical cost was $50,096 ± $23,998. The highest individual cost was for implants ($13,916; 24% of total costs). The second highest was inpatient room and ICU costs ($12,483; 22%); bone grafts were the third ($6,398; 11%). Increased major and minor structural curve, increased total (A/P) levels fused, and increased length of hospital stay predicted an increase in total cost. CONCLUSIONS: Major contributors to cost in NMS surgery are implants, inpatient room and ICU costs, and bone grafts. Independent predictors of higher cost are the degree of major and minor structural curve, total number of A/P levels fused, and length of hospital stay. These conclusions provide insight into costs associated with care for a medically fragile and challenging patient population.

Outcomes analysis of anterior-posterior fusion for low grade isthmic spondylolisthesis.

BACKGROUND: Traditional surgical treatment of isthmic spondylolisthesis is posterior-lateral fusion, but the addition of anterior surgery has been explored. The purpose of this study was to evaluate the surgical and clinical outcomes of anterior-posterior surgical treatment for low-grade isthmic spondylolisthesis. METHODS: Retrospectively, we enrolled 23 consecutive patients (mean age of 50) who underwent surgical treatment for low grade isthmic spondylolisthesis. The mean follow-up was 10 months. Basic demographic and radiographic data was collected. Pre- and post-surgical clinical surveys (VAS, ODI, and SF-36) were collected. RESULTS: All 23 patients underwent anterior interbody fusion with a femoral ring allograft or ICBG in combination with posterior lumbar decompression and fusion with instrumentation. The average slip percentage decreased from 23.2% to 19.0% (p = 0.24) while slip angle increased from 9.8° to 17.9° (p < 0.001) and average disc height decreased from 1.9 cm to 0.80 cm (p < 0.001). VAS scores decreased from 7.1 to 2.4 (p < 0.001), ODI scores decreased from 52.5 to 28.1 (p < 0.001), and SF-36 scores increased in the Physical Component Scale (PCS) from 29.5 to 42.6 (p < 0.001). CONCLUSION: In our study, patients demonstrated an improvement in the ODI as well the physical component scores of the SF-36, thus having a good clinical outcome.

Intervertebral foramen size and volume changes in low grade, low dysplasia isthmic spondylolisthesis.

STUDY DESIGN: Anatomic study. OBJECTIVE: The purpose of this study is to determine the effect of the slip amount, slip angle, and disc height on the geometry of the L5 foramen in low-grade, low-dysplasia isthmic L5 spondylolisthesis using a human cadaveric model. SUMMARY OF BACKGROUND DATA: Radicular pain and varying degrees of nerve root dysfunction are present in many adult isthmic spondylolisthesis patients and can be the result of compression of the L5 root within its foramen. METHODS: The intervertebral foramens of six L5 vertebra and sacrum cadaver specimens had a standardized pars defect created and were mounted on an adjustable frame. Plasticene molds of the foramens were made by varying sagittal translocation (0%, 12.5%, 25%, and 50%), slip angle (kyphotic 10° and lordotic 0°, 10°, 20°, and 30°), and disc height (0, 5, and 10 mm). The volume of each mold was measured. The surface area was determined by sagittally slicing on a microtome the mold and each section's face was measured by computer image analysis. RESULTS: The area and volume of the foramen at a sagittal slip of 0%, slip angle of 0°, and 0 mm disc height were used as a control. As disc height decreased from 10 to 5 mm, 10 to 0 mm, and 5 to 0 mm, the foramen area and volume significantly decreased (P < 0.05). Incremental slip percentage from 0% to 12.5%, 25%, and 50% produced significantly reduced foramen area and volumes (P < 0.05). As slip angle increased from 10° kyphosis to 0°, 10°, 20°, and 30° lordosis, foramen area and volume decreased (P < 0.05). CONCLUSION: Disc height and slip percentage had the largest effect on intervertebral foramen area and volume in this model of low-grade, low-dysplasia isthmic spondylolisthesis. Slip angle changes affected foramen area to a lesser degree. Surgical treatment strategies should consider restoration of disc height in cases with foraminal stenosis.

Hospital cost analysis of adolescent idiopathic scoliosis correction surgery in 125 consecutive cases.

BACKGROUND: Although achieving clinical success is the main goal in the surgical treatment of adolescent idiopathic scoliosis, it is becoming increasingly important to do so in a cost-effective manner. The goal of the present study was to determine the surgical and hospitalization costs, charges, and reimbursements for adolescent idiopathic scoliosis correction surgery at one institution. METHODS: We performed a retrospective review of 16,536 individual costs and charges, including overall reimbursements, for 125 consecutive patients who were managed surgically for the treatment of adolescent idiopathic scoliosis by three different surgeons between 2006 and 2007. Demographic, surgical, and radiographic data were recorded for each patient. Stepwise multiple linear regression analysis was employed to assess independent correlation with total cost and charge. Nonparametric descriptive statistics were calculated for total cost with use of the Lenke curve-classification system. RESULTS: The mean age of the patients was 15.2 years. The mean main thoracic curve measured 50 degrees, and the thoracolumbar curve measured 41 degrees. The cost varied with Lenke curve type: $29,955 for type 1, $31,414 for type 2, $31,975 for type 3, $60,754 for type 4, $32,652 for type 5, and $33,416 for type 6. Independently significant increases for total cost were found in association with the number of pedicle screws placed, the total number of vertebral levels fused, and the type of surgical approach (R(2) = 0.35, p

Major intraoperative neurologic monitoring deficits in consecutive pediatric and adult spinal deformity patients at one institution.

STUDY DESIGN: Retrospective review. OBJECTIVE: The purpose of this study was to assess the preoperative neurologic risk in a consecutive series of spinal deformity patients undergoing correction surgery at one institution. SUMMARY OF BACKGROUND DATA: During spinal deformity correction surgery, neurologic monitoring techniques are commonly applied to reduce the risk of neurologic deficits. While previous studies have demonstrated risk factors for neurologic changes in the setting of spinal surgery, these involved long time spans and heterogeneous patient populations. METHODS: Of 301 cases performed over 1 year, 281 cases were monitorable. Patients were grouped according to diagnosis: neuromuscular (NM) scoliosis, Sagittal Plane deformity, and Scoliosis. Demographic and surgical data were collected for neurologically monitorable patients. Coronal and sagittal parameters were measured using digital images of radiographs. Neurologic status was measured with somatosensory-evoked potentials and/or motor-evoked potentials. RESULTS: Primary NM scoliosis cases had the highest incidence of neurologic monitoring changes (NMC) (10%) while revision sagittal plane deformity had the second highest (9.8%). Sensitivity and specificity were both 100%. Overall incidence of neurologic deficit was 1.1%. Of the 13 NMCs patients, 3 patients had persistent neurologic deficit. Majority of NMCs occurred before deformity correction. In patients with NM scoliosis, NMCs increased with hybrid constructs with wires (P < 0.01). In patients with scoliosis, NMCs increased with increased body mass index, estimated blood loss, operative time, and postoperative coronal thoracolumbar curve magnitude (P < 0.04). In patients with primarily sagittal plane deformity, NMCs increased with preoperative proximal curve, postoperative proximal and thoracolumbar curves, and postoperative kyphosis and lordosis (P < 0.04). CONCLUSION: Primary NM scoliosis and revision sagittal plane deformities appear to carry greatest incidence of NMCs during surgical intervention. Most observed NMCs did not result in a permanent neurologic deficit. Neuromonitoring should be assessed throughout the entire surgical procedure. This study may aid surgeons and patients to better assess neurologic risks related to spinal deformity surgery.

The treatment of vertebral and chest wall deformities with expandable thoracoplasty and a prosthetic expandable implant.

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.

Biomechanical analysis of a disc prosthesis distal to a scoliosis model.

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.

Survivorship of coflex Interlaminar-Interspinous Implant.

BACKGROUND: The purpose of this study was to determine the indications for implantation of the coflex device (Paradigm Spine, LLC, New York, New York), assess long-term complications, and evaluate the long-term clinical outcomes of patients. METHODS: A total of 127 patients underwent placement of a coflex implant for various indications by one orthopaedic spine surgeon. The mean follow-up was 6.3 years. The original indications for implantation were determined based upon the data provided in the case report forms. Preoperatively and postoperatively, patients were asked to grade their low-back and leg pain using the visual analog scale (VAS) and the pain severity scale: no pain (0), mild pain (1), moderate pain (2), or severe pain (3). Patients were queried about their satisfaction with the surgical procedure. Follow-up radiographs were taken to determine any device-related issues. RESULTS: The most prevalent diagnoses for implantation were spinal stenosis (19.7%) and spinal stenosis with lumbar disc herniation (35.4%). The mean severity of low-back pain was decreased by 33% (from moderate to mild) at the 2-year follow-up (P < .001) and at the 5-year follow-up (from moderate to mild, P < .001). The mean severity of leg pain was decreased by 66% (from severe to mild) at the 2-year follow-up (P < .001) and at the 5-year follow-up (from severe to mild, P < .001). At the mean follow-up period of 6.3 years, a patient satisfaction query demonstrated that 7% were unsatisfied, 46% were satisfied, and 46% were very satisfied with their clinical outcome. Based on the follow-up radiographs, 92 of patients had no devicerelated issues and 8% had device-related issues. CONCLUSION: The data provided have demonstrated that the coflex implant provides pain relief for patients with low-back pain and leg pain. The most common indications for implantation were spinal stenosis and spinal stenosis with lumbar disc herniation. There were very few device-related complications. CLINICAL SIGNIFICANCE: Using coflex is a safe and viable option in the selection of instrumentation for spinal stabilization.