40. A prospective randomized clinical trial comparing anterior versus posterior stabilization for unilateral facet injuries of the cervical spine

40. A prospective randomized clinical trial comparing anterior versus posterior stabilization for unilateral facet injuries of the cervical spine

22S Proceedings of the NASS 19th Annual Meeting / The Spine Journal 4 (2004) 3S–119S multiple comparisons was used to calculate the change in the AA...

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22S

Proceedings of the NASS 19th Annual Meeting / The Spine Journal 4 (2004) 3S–119S

multiple comparisons was used to calculate the change in the AAOS pain scores at 1, 3 and 6 months compared to baseline. METHODS: 47 patients with low back pain, scheduled for facet joint injections, were prospectively enrolled and randomized into Groups A and B with ratio of 2:1. In Group A, patients had bone SPECT prior to facet injection. Group A patients with a positive SPECT were injected at the abnormal level(s) identified on the scan (Group A1). In case of negative scan (Group A2), the level(s) for injection was decided as in Group B. In Group B patients received facet injection without bone SPECT at the levels indicated by the referring physician. All patients completed a pain and function questionnaire (AAOS Lumbar Spine Survey) immediately before the facet injection, and at 1, 3 and 6 months. A cost analysis was performed using the current Medicare reimbursement rates at our institution. RESULTS: The change in the pain score at one month was significantly higher (p⬍0.004) in Group A1 than in the other two groups. In Group A1, 13/15 patients had significant improvement in pain score at one month. In contrast, there were only 2/16 patients with a significant improvement in Group A2 and 5/16 patients in Group B. The difference between groups was not significant at 6 months (p⫽0.067). In the patients with positive scans the number of facets injected was decreased from the 60 originally indicated by the referring physician to 27. The Medicare cost was reduced from $2,191 on average per patient to $1,865 with the use of bone SPECT. CONCLUSIONS: Bone SPECT can help identify patients who would benefit from facet joint injections. Facet joint injection has limited value in patients with negative bone SPECT. Use of bone SPECT also resulted in a decrease in the overall cost. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No Conflicts. doi: 10.1016/j.spinee.2004.05.039 4:56 39. Smoking, diabetes and excessive preoperative epidural steroid administration are risk factors for intraoperative dural tears Nicholas Ahn, MD1, Uri Ahn, MD2, Zachary Post, MD3, Thomas Salsbury, MD3, Harpreet Basran, MD3, Jason Datta3, Cody Harlan3, Brian Ipsen3, William Reed, Jr. MD4, Glenn Amundson, MD4, Alexander Bailey, MD4, William Hopkins, MD4, Gunnar Andersson5, Howard An5; 1 Heartland Hand and Spine Orthopaedic Center/ University of MissouriKansas City, Overland Park, KS, USA; 2New Hampshire Spine Institute, Bedford, NH, USA; 3University of Missouri- Kansas City, Kansas City, MO, USA; 4Heartland Hand and Spine Orthopaedic Center, Overland Park, KS, USA; 5Rush University / Rush- Presbyterian-St. Luke’s Medical Center, Chicago, IL, USA BACKGROUND CONTEXT: It is well known in the general surgery literature that smoking, diabetes, and steroid use are risk factors for weakened fascial tissues and wound dehiscence. Given that the dural sac is composed of a very thin layer of fibrous tissue that is thinner than but not unlike the abdominopelvic fascia, it would stand to reason that intraoperative dural tears may be more common in patients who smoke, have diabetes, or who were exposed to excessive preoperative epidural steroid injections. PURPOSE: This study was performed to determine risk factors for intraoperative dural tears during lumbar decompression surgery. STUDY DESIGN/SETTING: We performed a retrospective review of patients who had undergone primary lumbar decompression surgery for spinal stenosis between 1998 and 2003. All cases were performed in one of eight different hospitals which included two university/acamedic centers and six community hospitals. PATIENT SAMPLE: 1867 patients who had undergone primary lumbar decompression surgery for spinal stenosis with or without fusion between 1998 and 2003 were retrospectively studied. OUTCOME MEASURES: Cases in which an intraoperative dural leak had occurred were noted. METHODS: Information on age, sex, smoking history, diabetes, alcoholism, number of levels decompressed, number of levels fused, use of instrumentation, and number of preoperative epidural injections 6 months before

surgery were also collected. Stepwise logistic regression analyses were then used to determine the association between intraoperative dural tears and each of the independent variables while controlling for confounding factors. RESULTS: 123 patients in our study group sustained an intraoperative dural leak. Logistic regression analyses demonstrated a significant association between dural tears and smoking (OR⫽3.4, p⫽0.02), diabetes (OR⫽2.3, p⫽0.04), and ⬎3 preoperative epidural steroid injections 6 months prior to surgery (OR⫽1.6, p⫽0.04). There was no association between intraoperative dural tears and the remaining independent variables (p⬎0.05). The odds of sustaining an intraoperative dural leak were particularly high in patients with two or more of these risk factors (OR⫽6.7, p⫽0.04). CONCLUSIONS: Intraoperative dural tears are significantly higher in patients who smoke, have diabetes, or who were subjected to excessive epidural steroid injections (⬎3 in 6 months prior to surgery). In addition, patients with a combination of the above risk factors have a markedly increased risk of inadvertent intraoperative durotomy. The surgeon should exhibit additional caution in these patients and warn them of the increased risk of intraoperative dural tears. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No Conflicts. doi: 10.1016/j.spinee.2004.05.040

Wednesday, October 27, 2004 4:35–5:15 PM Concurrent Sessions 2B: Trauma Surgical Treatment 4:35 40. A prospective randomized clinical trial comparing anterior versus posterior stabilization for unilateral facet injuries of the cervical spine Brian Kwon, MD1, Marcel Dvorak, MD1, Charles Fisher, MD2, Michael Boyd, MD2, Peter Wing, MB2, Caroline Abramson, MA1, Allan Aludino, BSc2, Alexei Schwartzman, BSc2, Jennifer Brown, PT3, John Cobb, PT3; 1 University of British Columbia, Vancouver, British Columbia, Canada; 2 University of British Columbia, British Columbia, Canada; 3Vancouver General Hospital, British Columbia, Canada BACKGROUND CONTEXT: Unilateral facet fractures and dislocations are common injuries in the subaxial cervical spine. Surgical stabilization can be achieved posteriorly with lateral mass screws and/or wiring techniques, or anteriorly with discectomy and cervical plating. The optimal surgical approach, however, has not been established. PURPOSE: In this study, we sought to compare anterior versus posterior stabilization for unilateral facet injuries in a prospective randomized fashion. STUDY DESIGN/SETTING: Prospective randomized controlled trial conducted in a single level 1 trauma center. PATIENT SAMPLE: Individuals with a unilateral facet injury were enrolled in the study if they had an injury deemed to be suitable to singlelevel anterior or posterior stabilization, were over the age of 16 and were able to understand and use a patient-controlled analgesia unit. Excluded were individuals with a spinal cord injury, significant vertebral body injury, concomitant injuries or pre-existing medical conditions affecting mobility, pre-existing tolerance to opioids, or pre-existing cervical pathology. Apriori power calculation indicated 20 subjects per group. OUTCOME MEASURES: The primary outcome measure was the time required by patients to post-operatively achieve a standard set of discharge criteria which included independent mobility, an acceptable level of pain control on oral analgesics, and medical stabilization. Secondary outcome measures included acute post-operative pain and wound complications. Radiographic alignment and fusion, and both generic and diseasespecific outcome measures (SF-36 and NASS questionnaires) were assessed at 3, 6 and 12 months post-operatively.

Proceedings of the NASS 19th Annual Meeting / The Spine Journal 4 (2004) 3S–119S METHODS: Patients were randomized to anterior cervical discectomy and plating, or posterior fixation with lateral mass plating and/or posterior wiring. Post operative care was identical for both groups. RESULTS: Forty-two patients were randomized (20 anterior, 22 posterior) with the average age of 35.1 years. The median time to achieving standard discharge criteria was 2.75 days for the anterior and 3.25 days for the posterior group (p⫽0.21). Mean post-operative pain measured on days 1 and 2 using a 10 point visual analogue scale were 2.3⫾0.4 and 3.3⫾0.5 for anterior and posterior groups respectively (p⫽0.10). One of 20 anteriorly treated patients had an iliac crest wound infection, while 5 of 22 posteriorly treated patients had a wound infection. None of the anteriorly treated patients had demonstrable motion on flexion-extension films at one year, while almost 25% of posteriorly treated patients had demonstrable motion, with one requring anterior revision. Mean sagittal alignment was 9.2 degrees of lordosis in the anterior group, and 1.4 degrees of kyphosis in the posterior group. No significant difference in SF-36 physical and mental scores and NASS pain and neurology scores was found. CONCLUSIONS: No significant difference in the time to achieving a standard set of discharge criteria was found between the anteriorly and posteriorly treated patients. Wound problems were much more common in the posteriorly treated patients. Radiographically, the patients treated anteriorly had a higher fusion rate and better overall sagittal alignment. Ultimately, the generic and disease specific outcome scores did not differ significantly between the two groups, suggesting that, at least in the short term, the two techniques for stabilizing unilateral facet injuries are quite comparable. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: Author (BK) Grant Research Support: Vancouver Foundation: BCM 98-0115

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post-operatively on all patients and were independently reviewed for fusion, implant failure and loss of correction.Questionnaire and phone interview were conducted to evaluate patient satisfaction and work status. RESULTS: Eighty four consecutive patients treated the the short segment posterior indirect reduction technique. Fifty-five males and thirty-nine females. Average age thirty six years (range 18 to 56). Fifty-one patients were neurologically intact, thirty-three with significant neurologic deficit. Fourteen patients (17%) had additional visceral injuries requiring surgery, twenty-four (29%) patients had additional orthopaedic injuries requiring surgery. Six patients (7%) had non-contiguous spine fractures, ten patients had contiguous spinal injuies. Forty-six patients were injured secondary to a motor vehicle accident, twenty three patients were injured secondary to a significant fall. There were a total of one hundred fractures in these eighty four patients. T11 five, T12 twenty-five, L1 forty-five, L2 seventeen, L3 eight. The average surgical time one hundred and fifty-three minutes, average blood loss four hundred thirty cc. There were no implant failures, no infections, no neurologic deterioration. Loss of kyphosis correction at final follow-up six degrees. 83% patients returned to employment. Patient satisfaction with surgical treatment 85%. CONCLUSIONS: The posterior indirect reduction and instrumentation with the Synthes 6mm titanium shantz is a safe procedure with few drawbacks. The technique allows for immediate fracture stabilization from a posterior approach with a short operative time, minimum blood loss and low complication rate. The device appears to have sufficient biomechanical strength to maintain correction of the deformity while allowing for incorporation of the fusion. DISCLOSURES: Device or drug: USA synthes pedicle screws. Status: Approved for this indication. CONFLICT OF INTEREST: No Conflicts.

doi: 10.1016/j.spinee.2004.05.041 doi: 10.1016/j.spinee.2004.05.042 4:42 41. Short segment posterior indirect reduction and stabilization of thoracolumbar burst fractures: minimum two year follow up Patrick Connolly, MD1, Keith Coral2, Dan Lefebvre2, Matthew Bennett, MD3; 1UMASS Medical Center, Worcester, MA, USA; 2NY, USA; 3State University of New York Health Science Center at Syracuse, Syracuse, NY, USA

BACKGROUND CONTEXT: The treatment of thoracolumbar burst fractures remains controversial. Although posterior indirect reduction has been effective in clearing the canal in a laboratory model the clinical application of posterior short segment indirect reduction and stabilization remains controversial. PURPOSE: The purpose of this study was to evaluate our experience with short segment posterior Indirect reduction and stabilization of thoracolumbar burst fractures with a minimum two year follow –up. STUDY DESIGN/SETTING: Retrospective Review PATIENT SAMPLE: consecutive patients with Thoracolumbar burst fractures treated surgically with short segment posterior indirect reduction, stabilization and fusion. OUTCOME MEASURES: radiograph review for implant failure, loss of fixation loss of correction. Questionnaire/ Mcgill short form/ phone interview to evaluate pain, patient satisfaction, work status. METHODS: A retrospective review of the medical records at our institution, a level one trauma center, between January 1995–January 2000 identified four hundred seventeen burst fractures. Eighty-four patients were identified as having thoracolumbar fractures treated surgically with the short segment posterior indirect reduction technique alone. These patients are the subject of this report. Four USA Synthes 6 mm schantz and two 1/4 inch titanium rods were used in each case for segmental pedicle fixation. Iliac crest bone graft was used in every case for a posterior lateral fusion. Indications for surgery were three column burst fractures, canal compromise greater than 50%, kyphosis greater than 25 degrees, loss of body height greater than 50%, significant neurologic deficit and contiguous fractures at the thoracolumbar junction. Serial Radiographs were performed

4:49 42. Accuracy and safety of pedicle screw fixation in thoracic spine fractures Fisher Charles, MD1, Vic Sahajpal, MD2, Bailey Christoper, MD3, Michael Boyd, MD1, Brian Kwon, MD3, Marcel Dvorak, MD3; 1 University of British Columbia, Vancouver, British Columbia, Canada; 2 Memorial University of Newfoundland, St. John’s, Newfoundland, Canada; 3University of British Columbia, British Columbia, Canada

BACKGROUND CONTEXT: Cadaveric and clinical deformity studies would support the accuracy and safety of thoracic pedicle screws. No study has addressed safety and accuracy in a homogenous cohort of unstable thoracic spine fractures. PURPOSE: To determine if pedicle screws can be accurately and safely used for open reduction and internal fixation of unstable thoracic spine fractures. The secondary outcome is to determine if baseline variables including neurology and level influence accuracy of screw placement. STUDY DESIGN/SETTING: Study design was a prospective cohort efficacy study. Surgery was performed by 1 of 5 fellowship trained spine surgeons using fluoroscopic or radiographic control at one tertiary referral center. PATIENT SAMPLE: Included were patients with unstable thoracic fractures between T1 and T10 inclusive, with or without neurologic deficit. Pathologic fractures were excluded. Apriori power calculation showed 195 screws were necessary to establish an estimate of the true rate of pedicle wall violation accurate to within plus or minus 5 percent. OUTCOME MEASURES: Postoperative CT scans were performed using 3mm cuts in sagital and transverse planes. METHODS: Three independent reviewers assessed pedicle screw position. Screw position was initially categorized dichotomously, either within the pedicle or in violation of the pedicle wall. Further sub-classification of the pedicle wall infringement group was done using a 4-point categorical scale, which analyzed the direction and magnitude of perforation. Comparison of failure rates between selected baseline variables were carried out