Faculty Bibliography

Klippel-Feil syndrome (KFS), or congenital fusion of the cervical vertebrae, has been thought to be an extremely rare diagnosis. However, recent literature suggests an increased prevalence, with a high proportion of asymptomatic individuals. Occurring as a sporadic mutation or associated with several genes, the pathogenesis involves failure of cervical somite segmentation and differentiation during embryogenesis. Most commonly, the C2-C3 and C5-C6 levels are involved. KFS is associated with other orthopaedic conditions including Sprengel deformity, congenital scoliosis, and cervical spine abnormalities, as well as several visceral pathologies. There are several classification systems, some based on the anatomic levels of fusion and others on its genetic inheritance. Management of patients with KFS primarily involves observation for asymptomatic individuals. Surgical treatment may be for neurologic complaints, correction of deformity, concomitant spinal anomalies, or for associated conditions and varies significantly. Participation in sports is an important consideration. Recommendations for contact sports or activities depend on both the level and the number of vertebrae involved in the fusion. A multidisciplinary team should be involved in the treatment plan and recommendations for complex presentations.

BACKGROUND: Antifibrinolytics can reduce intraoperative blood loss. The primary aim of this study was to determine the efficacy of intraoperative tranexamic acid, epsilon-aminocaproic acid, and placebo at reducing perioperative blood loss and the transfusion rate in patients with adolescent idiopathic scoliosis undergoing posterior spinal arthrodesis. METHODS: This is a prospective, randomized, double-blind comparison of tranexamic acid, epsilon-aminocaproic acid, and placebo used intraoperatively in patients with adolescent idiopathic scoliosis. One hundred and twenty-five patients with adolescent idiopathic scoliosis were randomly assigned to the tranexamic acid, epsilon-aminocaproic acid, or control groups. Parameters recorded included estimated blood loss, hematocrit, blood product usage, drain output, and total blood losses. The primary outcomes were intraoperative blood loss and postoperative drainage. Secondary outcomes were transfusion requirements and hematocrit changes both intraoperatively and postoperatively. RESULTS: One hundred and twenty-five patients (ninety-seven female and twenty-eight male, with a mean age of fifteen years) were randomized to receive tranexamic acid (thirty-six patients), epsilon-aminocaproic acid (forty-two patients), or saline solution (forty-seven patients). The groups were similar at baseline, with one exception: the saline solution group had a higher estimated blood volume at baseline than the tranexamic acid group. Both tranexamic acid and epsilon-aminocaproic acid reduced the estimated blood loss per degree and estimated blood loss per pedicle screw. Epsilon-aminocaproic acid, but not tranexamic acid, reduced estimated blood loss and estimated blood loss per level. Tranexamic acid also reduced total blood losses compared with epsilon-aminocaproic acid or saline solution. In an analysis controlling for level, degree, and number of anchors, tranexamic acid reduced drain output and total blood losses. Tranexamic acid or epsilon-aminocaproic acid had a smaller decrease in hematocrit postoperatively. In an analysis controlling for the mean arterial pressure during surgical exposure, tranexamic acid reduced estimated blood loss and total blood losses. Overall, antifibrinolytics (tranexamic acid or epsilon-aminocaproic acid) reduced estimated blood loss, total blood losses, and the decline in hematocrit postoperatively compared with saline solution. There was no difference among the groups with respect to the transfusion rate, duration of surgery, levels fused, or pedicle screws placed. CONCLUSIONS: Tranexamic acid and epsilon-aminocaproic acid reduced operative blood loss but not transfusion rate. Tranexamic acid is more effective at reducing postoperative drainage and total blood losses compared with epsilon-aminocaproic acid. Maintenance of the mean arterial pressure at <75 mm Hg during surgical exposure appears to be critical for maximizing antifibrinolytic benefit. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND CONTEXT: Anti-fibrinolytics have been proven effective in reducing intra-operative blood loss in several settings. However, their value in Adolescent Idiopathic Scoliosis (AIS) remains unclear. No previous study has compared tranexamic acid (TXA), epsilon aminocaproic acid (EACA), and placebo in regards to their ability to limit operative blood loss, post-operative drain output, and transfusion rate. PURPOSE: To determine the efficacy of intra-operative anti-fibrinolytics at reducing peri-operative blood loss and transfusion rate in patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion of at least 5 levels. STUDY DESIGN/SETTING: Prospective, double-blind, randomized clinical trial. PATIENT SAMPLE: Patients between the ages of 10-21 with a diagnosis of adolescent idiopathic scoliosis treated with posterior spinal fusion of at least five levels were prospectively enrolled. OUTCOME MEASURES: Primary outcome measures include estimated blood loss, drain output, total blood loss, and transfusion rate. Secondary outcome measures include pre-, intra-, and post-operative hematocrit, duration of surgery, complications, and length of hospital stay. METHODS: This is a prospective, randomized, double-blind comparison of TXA, EACA and placebo used intra-operatively in patients with AIS. 119 AIS patients were randomly assigned to TXA, EACA, or control. TXA was administered at 10 mg/ kg for a loading dose followed by 1 mg/kg-hr, while EACA was given at a 10 fold higher dose. Parameters recorded included estimated blood loss (EBL), pre, intra and post-operative hematocrit, blood product usage, post-operative drain output, and total blood loss. RESULTS: 119 patients were randomized to TXA (n535), EACA (n538), or placebo (n546). There were 93 females and 26 males, average age 15. Most pre-operative characteristics were similar, however saline patients had significantly greater height, weight, and estimated blood volume vs TXA (p<.05). TXA patients had significantly lower hematocrit at anesthesia start vs saline (33.2 vs 35.7, p<.05). There was no difference in transfusion rate, duration of surgery, levels fused, or anchors placed. When controlling for mean arterial pressure (MAP) during exposure, TXA reduced EBL vs saline (p<.05), and reduced total blood loss, total blood loss per anchor, and total blood loss per degree of curve vs saline (p<.05). Additionally, EACA reduced EBL per anchor vs saline in patients with reduced mean exposure MAP (p<.05). Neither TXA nor EACA reduced EBL or total blood loss in patients with mean exposure MAPO75. While total drain output was not reduced for TXA or EACA vs saline, TXA showed reduced drain output per anchor and degree curve (p<.05) compared to saline. CONCLUSIONS: Our results suggest that anti-fibrinolytics safely reduce blood loss in patients with AIS. However, transfusion rates were not impacted. Further, mean arterial pressure during surgical exposure appears to be a critical factor in the efficacy of anti-fibrinolytic action

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 <or= 0.03). Independently significant increases for reimbursement were found in association with the number of pedicle screws placed and the type of surgical approach (R(2) = 0.12, p <or= 0.02). The hospital was reimbursed 53% of total charges and 120% of total costs. Reimbursement was highly correlated with charge (r = 0.45, p < 0.001). For rehospitalizations, the hospital was reimbursed 65% of charges and 93% of costs. CONCLUSIONS: The largest contributors to overall cost were implants (29%), intensive care unit and inpatient room costs (22%), operating room time (9.9%), and bone grafts (6%). There were three significant independent predictors of increased total cost: the surgical approach used, the number of pedicle screws placed, and the number of vertebral levels fused. This study characterizes the relative contributions of factors that contribute to total costs, charges, and reimbursements that can, in time, identify potential areas for cost reduction or redistribution of resources in the surgical treatment of adolescent idiopathic scoliosis

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

OBJECT: Although transforaminal lumbar interbody fusion (TLIF) is an increasingly popular surgical technique, there are a limited number of studies in which investigators have stratified outcome data with respect to surgical indications or documented radiographically proven and clinical results with respect to disc space height (DSH). The authors conducted a study to evaluate the long-term outcomes after TLIF with respect to surgical indication and radiographic/neuroimaging results. METHODS: Thirty-three consecutive TLIF-treated patients underwent follow-up investigation for a mean of 37 months. Isthmic spondylolysis was present in eight patients, recurrent disc herniation in 14, and degenerative disc disease (DDD) in 11. The operative technique involved the placement of interbody structural allograft, pedicle screw instrumentation, and morcellized autograft in the anterior interbody space and the contralateral intertransverse gutter. Surgery was performed at L4-5 in 16 patients, L5-S1 in 14, L3-4 in two, and both L4-5 and L5-S1 in one patient. Preoperative symptoms were back pain (in 91% of cases), leg pain (in 94%), sensory loss (in 67%), and motor deficits (in 30%). Postoperatively, back pain was improved in 67% of the patients, unchanged in 27%, and worsened in 7%. Leg pain improved in 80% of patients, was unchanged in 10%, and worsened in 10%. Outcome, as measured using the Prolo Functional and Economic Scales, improved from a score of 4.9 to 7. In patients with spondylolysis and recurrent disc herniation outcomes were better than in those with DDD only. There was no correlation of outcome with symptom duration, patient age, or level of surgery. In an independent review of pre- and late postoperative radiographs no significant differences in lordosis angles, Cobb angles, or DSHs were found. Fusion occurred in all cases. CONCLUSIONS: The TLIF procedure was associated with good clinical outcomes and a high fusion rate but no change in the DSH. Patients who present with spondylolysis and recurrent herniations experience better outcome than those with degenerative disease alone

Degenerative lumbar spinal stenosis is a problem of increasing importance as the population ages and functional expectations remain high. It usually develops secondary to spondylosis. Classic symptoms of lumbar stenosis are back pain, radiating leg pain, and sciatica exacerbated by walking. This neurogenic claudication usually can be distinguished from other conditions that produce leg pain during the history and physical examination. Plain radiographs suffice for persons with mild to moderate stenosis; more severe symptoms or neurologic involvement calls for other imaging. Management begins conservatively with anti-inflammatory agents and local modalities. Epidural corticosteroids are being used increasingly despite controversy. Surgery may be indicated for patients in whom nonoperative treatment is unrewarding and is safe even for very elderly persons. (33 ref 1 bib) <19>

STUDY DESIGN. Computed tomography scans of the dens were performed on patients who had no atlantoaxial pathology. OBJECTIVES. To determine whether one or two screws is optimal for fracture fixation and whether two screws can always negotiate the intramedullary odontoid cavity. SUMMARY OF BACKGROUND DATA. Fixation of Type II dens fractures traditionally has used C1-C2 posterior wiring and fusion. Two screws placed across an odontoid fracture as a method of rigid internal fixation also has been described. However, it is not known whether two screws can always negotiate the odontoid canal. METHODS. Ninety-two consecutive computerized tomography scans of the dens were performed on adults who had no atlantoaxial pathology. Measurements were taken from the scan and compared with the cross-sectional diameter of two odontoid screws. RESULTS. The critical diameter for the placement of two 3.5-mm cortical screws with tapping was 9.0 mm. This dimension was present in 95% of the patients studied. CONCLUSIONS. Correct orientation of the computerized tomography scanner is critical for accurate measurements. Two 3.5-mm screws can be used in internal fixation of Type II dens fractures in 95% of the patients if the inner cortex is tapped