Proceedings of the NASS 19 th Annual Meeting / The Spine Journal 4 (2004) 3S–119S 116S STUDY DESIGN/SETTING: Patients undergoing single level microdis- cectomy procedures from 2001 to 2003 were reviewed. Patients with prior lumbar surgeries were excluded. Retrospective review of surgical complica- tions, hospital stay, estimated blood loss, relief of symptoms, and need for reoperation was performed. PATIENT SAMPLE: Sixty-two consecutive patients who underwent a total of sixty five procedures over a 3-year period were retrospectively reviewed. OUTCOME MEASURES: Review of patient charts for recurrence of symptoms was performed. VAS scores pre- and postoperatively was also reviewed. METHODS: All patients had single-level disc herniations confirmed with MRI studies and had failed a proper course of conservative care including NSAIDs, physical therapy, and epidural injections. The data used for com- parison of these two procedures include the duration of hospital stay, blood loss, surgical complications, persistence of symptoms, need for revision surgery, and clinical results. RESULTS: Of the total sixty-two patients, a standard microdiscectomy utilizing standard “open” retractors were performed on 39 patients, while 24 had surgery using the MetRx Tubular retractors. For the patients who underwent the classical approach, two dural tears and one patient recurrent radiculopathy were noted. Of the 24 patients who underwent discectomy using the tubular retractors, one dural tear and five recurrent radiculopathies were noted. None of the patients suffered nerve injury or infection during or following the procedures. There was no statistically significant difference between the two groups as far as intraoperative complications, post- operative complications, total procedure time, or hospital stay. The average estimated blood loss was 57.7cc for the patients who underwent the classical approach versus 53.9cc for the patients who underwent the tubular approach. The average hospital stay was 1.42 days for patients who underwent the classical approach and 0.75 days for patients who underwent the tubular approach. CONCLUSIONS: There appears to be no significant difference between the minimally invasive tubular retractors or standard retractors for patients undergoing single-level lumbar microdiscectomy procedures. There may be a trend towards a shorter hospital stay and perhaps a higher rate of recurrent symptoms with the use of the tubular retractors, however, it appears that both methods are successful and provide similar clinical results. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No Conflicts. doi: 10.1016/j.spinee.2004.05.236 P80. Restoration in osteoporotic vertebral fracture: kyphoplasty is superior to postural correction Joseph Lane, MD 1 , Jason Koob 1 , Michael Shindle, MD 2 , Susan Bukata, MD 1 , Margaret Peterson, PhD 1 ; 1 Hospital for Special Surgery, New York, NY, USA; 2 Johns Hopkins University, Baltimore, MD, USA BACKGROUND CONTEXT: It has recently been demonstrated that many vertebral compression fractures (VCF’s) are mobile and positional correction can lead to clinically significant height restoration. PURPOSE: The purpose of this report was to test the hypothesis that positional maneuvers are statistically inferior to kyphoplastic balloon tamps for the reduction of low energy vertebral compression fractures. STUDY DESIGN/SETTING: Retrospective review, Hospital for Spe- cial Surgery. PATIENT SAMPLE: 25 consecutive patients with 43 vertebral compres- sion fractures. OUTCOME MEASURES: Radiographs were evaluated for percent height restoration related to positioning and balloon kyphoplasty. METHODS: Preoperative standing lateral radiographs of the fractured vertebrae were compared with prone cross-table lateral radiographs with the patient in a hyper-extension position on pelvic and sternal rolls. Following positional manipulation patients underwent a unilateral balloon kypho- plasty. Postoperative standing radiographs were evaluated for percent of height restoration related to positioning and balloon kyphoplasty. RESULTS: In the central portion of the vertebrae, the average preoperative fractured vertebral body height compared to a “normal vertebral body” was 60.12%. Postural maneuvering and kyphoplasty increased central height to 66.16% (p0.005) and 82.95% (p0.001) respectively. The percent restoration of the central portion of the vertebral body with extension positioning was 10.44%, median=11.11%, and after balloon kyphoplasty was 59.31%, median=62.18%, (p0.001). Thus, while positioning provided an average of 10.44% restoration, kyphoplasty provided an additional 48.87% restoration in the central portion. With operative positioning, 51.16% of VCF’s had 10% restoration of the central portion of the verte- bral body as compared with 90.7% after balloon kyphoplasty (p=0.0014). CONCLUSIONS: Proponents of vertebroplasty advocate that placing the patient in the prone position in extension should lead to adequate reduction of the fracture due to dynamic mobility. Although this study supports the concept that many VCF’s can be moved with positioning, balloon kyphoplasty enhanced the height reduction 5 fold over the positioning maneuver alone and accounted for over 75% of the ultimate reduction. Even in these patients with marked positional improvement, kyphoplasty provided significant additional height restoration. If height restoration is the goal, kyphoplasty is clearly superior in most cases to the positioning maneuver alone. DISCLOSURES: Device or drug: Kyphon inflatable balloon tamp. Status: Approved for this indication. Device or drug: Polymethylmethacrylate cement (PMMA). Status: Not approved for this indication. CONFLICT OF INTEREST: Author (jl) Consultant: Kyphon; Author (jl) Speaker’s Bureau Member: Kyphon; Author (jl) Grant Research Sup- port: Kyphon. doi: 10.1016/j.spinee.2004.05.237 P25. Evaluation of pedicle screw placement in the deformed spine using intraoperative plain radiographs: a comparison with CT scans Yong-Jung Kim 1 , Lawrence Lenke 1 *, Gene Cheh, MD 2 , K. Daniel Riew 1 ; 1 Washington University in St. Louis, St. Louis, MO, USA; 2 MO, USA BACKGROUND CONTEXT: Is it possible to predict malpositioned screws on plain intraoperative radiographs? PURPOSE: To evaluate the sensitivity of intraoperative plain radiographs to detect malpositioned pedicle screws in the deformed thoracic and lumbar spine. STUDY DESIGN/SETTING: A retrospective radiographs and CT scan review. PATIENT SAMPLE: 49 patients. OUTCOME MEASURES: Radiographs and CT scans. METHODS: A total of 776 pedicle screws (618 thoracic pedicle screws and 158 lumbar pedicle screws) inserted from T1 to L4 in 49 patients with postoperative CT scan data were investigated. According to the diagnoses, the number of screws placed were: 692 for scoliosis (45 patients), and 84 for Scheuermann’s kyphosis (4 patients). The position of the pedicle screw inserted was graded as an accurate screw (n=711) with acceptable position vs inaccurate screw (n=65) with significant violation, defined as the central line of the inserted pedicle screw was out of the outer cortex of the pedicle wall with CT scans taken after operation. Comparative analysis of these 65 inaccurate screws (15 medial violations and 50 lateral violations) using postoperative CT scan and intraoperative plain radiographs was done. All CT scan evaluations were performed independently by three different spine surgeons who had not been part of the operation. Three plain radiographic criteria were used to judge the accuracy of screw position: 1) violation of the harmonious segmental change of the tips of the inserted screws (medial or lateral out), 2) no crossing of medial pedicle wall by the pedicle screw inserted (lateral out), and 3) violation of the imaginary midline of the vertebral body using the posterior upper spinolaminar junction in the plain PA x-ray by the absolute position of the tip of the inserted pedicular screw