- Email: [email protected]
10:08 62. Hip-Spine Syndrome: The Effect of Total Hip Replacement Surgery Upon Low Back Pain in Patients With Severe Osteoarthritis of the Hip
Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S CONCLUSIONS: In order to achieve grafted bone union, rigid immobilization of the grafts is required. At the same time, adequate stress must be transmitted to the graft bone during the reparative period to stimulate the repair as well. The balance between these two factors is most important. We have made it clear that spinal reconstruction of posterior multilevel pedicle screw fixation with the anterior titanium mesh cage reconstruction method might allow adequate stress for remodeling of the bone graft inside the titanium mesh cage using a finite element method. Our overall results show this spinal reconstruction method is reliable for achieving bilological fusion in the patients who underwent TES operation and in whom a relatively long survival is expected. However, further development should be required for TES in the lower lumbar level. FDA DEVICE/DRUG STATUS: Titanium Mesh Cage: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.082
Thursday, September 28, 2006 10:02–10:45 AM General Session: Outcomes in the Aging Spine 10:02 61. Minimum Acceptable Outcomes and Expectations After Fusion for Degenerative Disc Disease Eugene Carragee, MD1, Ivan Cheng, MD2, Brian J.C. Freeman, MD, FRCS3, Mark J. Wang, MD1, Todd F. Alamin, MD4, Erica Van Den Haak, BS1; 1Stanford University, Stanford, CA, USA; 2Stanford School of Medicine, Stanford, CA, USA; 3Queen’s Medical Centre Nottingham, Nottingham, CA, USA; 4Stanford University School of Medicine, Stanford, CA, USA BACKGROUND CONTEXT: While many studies have attempted to quantify objective observations and subjective patient reports, it remains problematic to define success after spinal surgery. In previous reports we have determined the minimal acceptable and expected outcomes of spinal fusion for different diagnoses. In this paper we report on the achievement of minimal acceptable outcome after spinal surgery for degenerative disc disease at two major centers. PURPOSE: To determine the rate of achievement of ‘‘expected’’ and ‘‘minimally acceptable’’ outcomes in patients having spinal surgery for DDD. STUDY DESIGN/SETTING: Clinical descriptive study of outcomes after spinal fusions for DDD compared with expectations and minimal acceptable outcomes determined prospectively in patients having spinal fusion. PATIENT SAMPLE: 94 consecutive patients awaiting surgery for DDD were evaluated to determine baseline expectations and minimum acceptable outcomes. 111 patients having anterior-posterior fusion for DDD at two large academic centers were followed for 2 years to determine the rates of achievement of expected and minimum acceptable outcomes. OUTCOME MEASURES: Outcomes were assessed using the visual analog scale (VAS) for the severity of back and leg pain, the Oswestry Disability Index (ODI), pain medication usage, and work loss by standard questionnaire. METHODS: Minimum acceptable outcome and expectations were determined prospectively in 94 consecutive degenerative disc patients (38 male, 56 female). Baseline preoperative values were assessed using the visual analog scale (VAS) for the severity of back and leg pain, the Oswestry Disability Index (ODI), and a standard questionnaire which recorded a history of pain medication usage, preoperative symptom duration, work status, and amount of preoperative work loss. These subjects were then given two standardized forms to complete, indicating both minimum-acceptable
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and expected outcomes, and signifying lowest level of outcome for which they would undergo surgery and the outcome they expect to have postoperatively, respectively. Subjects from two large academic centers were followed for 2 years and their outcomes were compared with the expected and minimally acceptable outcomes previously determined. RESULTS: Subjects about to undergo fusion for degenerative disc disease group indicated the average minimally acceptable improvement to be ODImin529.2, VASmin54.02/10, and an expected improvement to be ODIexp537.5 (p ! .001) and VASexp55.32/10 (p ! .001). 90% of subjects expected to go off all narcotics and be working in some capacity. Approximately 50% of subjects at each center met minimally acceptable outcomes for pain and ODI, but few met minimal acceptable medication and work levels. Less than 30% of patients met the ‘‘expected’’ outcomes for pain, ODI, medications, or work status. CONCLUSIONS: Patients with degenerative disc disease have relatively high minimal and expected outcomes for spinal fusion when agreeing to surgery. These outcome expectations exceed the minimally clinically important difference referenced in previous studies and are not met in a majority of subjects. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.394
10:08 62. Hip-Spine Syndrome: The Effect of Total Hip Replacement Surgery Upon Low Back Pain in Patients With Severe Osteoarthritis of the Hip Peleg Ben-Galim, MD1, Tal Ben-Galim2, Nahshon Rand, MD3, Shmuel Dekel4, Yizhar Floman, MD3; 1Baylor College of Medicine, Houston, TX, USA; 2Hadassah University Hospital, Jerusalem, Israel; 3 Israel Spine Center, Tel-Aviv, Israel; 4Tel-Aviv Medical Center, Tel-Aviv, Israel BACKGROUND CONTEXT: Severe osteoarthritis of the hip causes abnormal spinal sagittal alignment and balance as well as a wobbling gait and is associated with low back pain. Total hip replacement surgery (THR) is effective in alleviating hip pain and function and improves gait. PURPOSE: To assess the clinical and functional effect total hip replacements surgery has upon low back pain. STUDY DESIGN/SETTING: Prospective clinical study. PATIENT SAMPLE: Twenty-five consecutive adults scheduled for total hip replacement surgery due to severe hip joint osteoarthritis were recruited. The 25 study participants included 15 females and 10 males with a mean age of 67.4 years (range 32–84 years). OUTCOME MEASURES: A detailed, thorough history and physical examination of both the hip and spine were conducted (including hip range of motion and the presence and degree of flexion contracture). Functional outcome scores were assessed separately for the hips and for the spine. The Harris Hip Score was used to evaluate hip-related symptoms in addition to the visual analogue scale specifically for hip pain. The Oswestry spinal disability score was used to evaluate spine-related symptoms in addition to the visual analogue scale specifically for low back pain. METHODS: Patients included in this study had to demonstrate clinical evidence of debilitating hip pain, limited range of motion, and radiographic changes characteristic of severe hip joint osteoarthritis. Exclusion criteria included previous hip and/or spinal fusion or instrumentation surgery. All patients were clinically assessed by an independent internal medicine physician including history, physical examination, and functional scores preoperatively as well as 3 months post-THR using standard validated outcome measures as described above.
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Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S
RESULTS: Both hip pain VAS scores and Harris hip scores were significantly better after THR. Mean hip pain VAS scores were 7.08 before and 2.52 after THR surgery (p!.01). Harris hip scores were 45.74 before and 81.8 after the surgery (p!.01). Both low back pain VAS scores, as well as Oswestry spinal disability scores were significantly better after total hip replacement surgery. Mean low back pain VAS scores were 5.04 before and 3.68 after THR surgery (p5.013). Oswestry spinal disability scores were 36.72 before and 24.08 after total hip replacement surgery (p5.02). CONCLUSIONS: Low back pain was alleviated and spinal functional assessment indexes were significantly improved after total hip replacement surgery. This study, while pointing to the well known clinical association between hip and spine pathology, is among the first studies that demonstrates the clinical benefits total hip replacement surgery has upon back pain. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.085
10:14 63. Decompression and Instrumented Fusion for Management of Degenerative Lumbar Scoliosis Christopher Furey1, Sanford Emery2; 1Case Western Reserve University, Cleveland, OH, USA; 2West Virginia University School of Medicine, Morgantown, WV, USA BACKGROUND CONTEXT: Surgical management of adult degenerative scoliosis is a challenging problem with several different options available to the surgeon. PURPOSE: To assess the long-term efficacy of decompression and fusion employing pedicle screw instrumentation and iliac crest bone grafting in the treatment of degenerative scoliosis, with special attention to the nature and frequency of postoperative complications and the need for re-operation. STUDY DESIGN/SETTING: A retrospective analysis of clinical and radiographic outcomes. PATIENT SAMPLE: 42 adults (32 women and 10 men). Six patients had prior a lumbar decompression, although none had prior fusion. OUTCOME MEASURES: Specific queries regarding relief of back pain and leg pain, improvement in quality of life, satisfaction of preoperative expectations, and willingness to repeat the same procedure in hindsight. Plain radiograpghs in each case and CT scan if there was concern for pseudarthrosis. METHODS: All levels with spinal stenosis were decompressed including bilateral foraminotomies. All levels decompressed were fused as were any levels with lateral listhesis greater than 6 millimeters. The proximal extent of the fusion was at the lowest neutral vertebrae in the upper lumbar or lower thoracic spine. Fusion was extended to the sacrum only if an L5S1 spondylolisthesis was present (6 cases), but otherwise was stopped at L5. Average follow-up was 4.2 years (range 2.0–8.4 years). RESULTS: Relief of leg pain was excellent in 83%, good in 12%, fair or poor in 5%. Relief of back pain was excellent in 55%, good in 33%, fair or poor in 12%. 86% of patients felt there was improvement in their lifestyle postoperatively. 81% of patients felt their preoperative expectations had been met or exceeded. Posterolateral fusion was noted to be solid on plain radiographs by 6 months in 86% and marginal in 10%. There were two cases (4%) with pseudarthrosis. Positive outcomes were not significantly affected by number of levels fused or extension of fusion into the thoracic spine proximally or to the sacrum distally. Improvement in sagittal balance as measured on pre- and postoperative radiographs did not correlate with a favorable outcome. Presence of solid fusion did correlate with a favorable outcome. Eight patients (19%) required further surgery. Two patients (4%) with pseudarthrosis required revision instrumented fusion, two patients (4%) with early postoperative infections required surgical washouts with preservation of
instrumentation. Two patients (4%) had elective removal of painful instrumentation after 1 year. Two patients (4%) developed proximal junctional kyphosis requiring extension of fusion into the lower thoracic spine. CONCLUSIONS: Posterior decompression and fusion with pedicle screw instrumentation and iliac crest grafting is an effective treatment for adult degenerative scoliosis. Relief of leg pain is the most predictable outcome, although most patients achieve satisfactory relief of back pain as well. This surgical option is aggressive for older patients, with potential for significant complications and thus should be reserved for those patients who have failed conservative management and who are suitable medical candidates. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.086
10:20 64. Neurologic Complications of Pedicle Subtraction Osteotomy: A Ten-Year Review Jacob Buchowski, MD, MS1, Craig Kuhns, MD1, Ronald Lehman, Jr., MD2, Yongjung Kim, MD1, Lawrence Lenke, MD1, Keith Bridwell, MD1; 1 Washington University in St. Louis, St. Louis, MO, USA; 2Walter Reed Army Medical Center, Washington, DC, USA BACKGROUND CONTEXT: Pedicle subtraction osteotomy (PSO), which is performed by resecting the posterior elements, pedicles, and vertebral body through a posterior approach, is frequently used to correct fixed sagittal imbalance creating approximately 30 of lordosis at the level of the osteotomy. This is a technically demanding procedure and can be fraught with complications. Nevertheless, no reports of neurologic complications after PSOs are available in the peer-reviewed literature. PURPOSE: The objectives of this study were to evaluate intra- and postoperative neurologic deficits after PSOs, to determine the risk factors associated with the development of a neurologic complication after PSO, to examine treatment strategies, and to analyze patient outcome. STUDY DESIGN/SETTING: A retrospective cohort study. PATIENT SAMPLE: Adult patients with fixed sagittal imbalance who underwent a pedicle subtraction osteotomy at a single tertiary referral spine center. OUTCOME MEASURES: Radiographic parameters and clinical outcome measures. METHODS: A total of 114 consecutive patients (84 women and 28 men) with an average age of 54.7613.9 years treated over a 10-year period (1995-2005) with a pedicle subtraction osteotomy for fixed sagittal imbalance were evaluated. The medical records were reviewed and intraoperative electrophysiologic data were analyzed. Radiographic analysis including assessment of thoracic kyphosis, lumbar lordosis, as well as sagittal and coronal balance was performed. RESULTS: A total of 114 pedicle subtraction osteotomies were performed. After surgery, thoracic kyphosis increased from 28.2618.6 to 35.4614.7 (p!.012). Similarly, lumbar lordosis increased from (-16.3)619.5 to (-50.2)615.2 (p!.001). Sagittal balance improved from 137672 mm preoperatively to 21652 mm postoperatively (p!.001). The incidence of intra- and postoperative neurologic deficit was 10.5% (12 of 114 patients). Neurologic deficits were found intraoperatively during a Stagnara wake-up test in three patients, immediately postoperatively in the operating room suite in four patients, and in a delayed manner in the remaining five patients. Although triggered EMGs were not used in all patients, electrophysiologic testing did not detect the deficit in any of the patients. Deficits were always unilateral and usually did not correspond to the level of the osteotomy. In nine patients surgical intervention consisting of central enlargement and further decompression was required. Four patients had weakness of multiple muscle groups. Neurologic deficits included weakness of: tibialis anterior (7 patients), quadriceps (5 patients), extensor hallucis longus (3 patients), flexor hallucis longus (1 patient), and cauda
Thursday, September 28, 2006 10:02–10:45 AM General Session: Outcomes in the Aging Spine 10:02 61. Minimum Acceptable Outcomes and Expectations After Fusion for Degenerative Disc Disease Eugene Carragee, MD1, Ivan Cheng, MD2, Brian J.C. Freeman, MD, FRCS3, Mark J. Wang, MD1, Todd F. Alamin, MD4, Erica Van Den Haak, BS1; 1Stanford University, Stanford, CA, USA; 2Stanford School of Medicine, Stanford, CA, USA; 3Queen’s Medical Centre Nottingham, Nottingham, CA, USA; 4Stanford University School of Medicine, Stanford, CA, USA BACKGROUND CONTEXT: While many studies have attempted to quantify objective observations and subjective patient reports, it remains problematic to define success after spinal surgery. In previous reports we have determined the minimal acceptable and expected outcomes of spinal fusion for different diagnoses. In this paper we report on the achievement of minimal acceptable outcome after spinal surgery for degenerative disc disease at two major centers. PURPOSE: To determine the rate of achievement of ‘‘expected’’ and ‘‘minimally acceptable’’ outcomes in patients having spinal surgery for DDD. STUDY DESIGN/SETTING: Clinical descriptive study of outcomes after spinal fusions for DDD compared with expectations and minimal acceptable outcomes determined prospectively in patients having spinal fusion. PATIENT SAMPLE: 94 consecutive patients awaiting surgery for DDD were evaluated to determine baseline expectations and minimum acceptable outcomes. 111 patients having anterior-posterior fusion for DDD at two large academic centers were followed for 2 years to determine the rates of achievement of expected and minimum acceptable outcomes. OUTCOME MEASURES: Outcomes were assessed using the visual analog scale (VAS) for the severity of back and leg pain, the Oswestry Disability Index (ODI), pain medication usage, and work loss by standard questionnaire. METHODS: Minimum acceptable outcome and expectations were determined prospectively in 94 consecutive degenerative disc patients (38 male, 56 female). Baseline preoperative values were assessed using the visual analog scale (VAS) for the severity of back and leg pain, the Oswestry Disability Index (ODI), and a standard questionnaire which recorded a history of pain medication usage, preoperative symptom duration, work status, and amount of preoperative work loss. These subjects were then given two standardized forms to complete, indicating both minimum-acceptable
31S
and expected outcomes, and signifying lowest level of outcome for which they would undergo surgery and the outcome they expect to have postoperatively, respectively. Subjects from two large academic centers were followed for 2 years and their outcomes were compared with the expected and minimally acceptable outcomes previously determined. RESULTS: Subjects about to undergo fusion for degenerative disc disease group indicated the average minimally acceptable improvement to be ODImin529.2, VASmin54.02/10, and an expected improvement to be ODIexp537.5 (p ! .001) and VASexp55.32/10 (p ! .001). 90% of subjects expected to go off all narcotics and be working in some capacity. Approximately 50% of subjects at each center met minimally acceptable outcomes for pain and ODI, but few met minimal acceptable medication and work levels. Less than 30% of patients met the ‘‘expected’’ outcomes for pain, ODI, medications, or work status. CONCLUSIONS: Patients with degenerative disc disease have relatively high minimal and expected outcomes for spinal fusion when agreeing to surgery. These outcome expectations exceed the minimally clinically important difference referenced in previous studies and are not met in a majority of subjects. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.394
10:08 62. Hip-Spine Syndrome: The Effect of Total Hip Replacement Surgery Upon Low Back Pain in Patients With Severe Osteoarthritis of the Hip Peleg Ben-Galim, MD1, Tal Ben-Galim2, Nahshon Rand, MD3, Shmuel Dekel4, Yizhar Floman, MD3; 1Baylor College of Medicine, Houston, TX, USA; 2Hadassah University Hospital, Jerusalem, Israel; 3 Israel Spine Center, Tel-Aviv, Israel; 4Tel-Aviv Medical Center, Tel-Aviv, Israel BACKGROUND CONTEXT: Severe osteoarthritis of the hip causes abnormal spinal sagittal alignment and balance as well as a wobbling gait and is associated with low back pain. Total hip replacement surgery (THR) is effective in alleviating hip pain and function and improves gait. PURPOSE: To assess the clinical and functional effect total hip replacements surgery has upon low back pain. STUDY DESIGN/SETTING: Prospective clinical study. PATIENT SAMPLE: Twenty-five consecutive adults scheduled for total hip replacement surgery due to severe hip joint osteoarthritis were recruited. The 25 study participants included 15 females and 10 males with a mean age of 67.4 years (range 32–84 years). OUTCOME MEASURES: A detailed, thorough history and physical examination of both the hip and spine were conducted (including hip range of motion and the presence and degree of flexion contracture). Functional outcome scores were assessed separately for the hips and for the spine. The Harris Hip Score was used to evaluate hip-related symptoms in addition to the visual analogue scale specifically for hip pain. The Oswestry spinal disability score was used to evaluate spine-related symptoms in addition to the visual analogue scale specifically for low back pain. METHODS: Patients included in this study had to demonstrate clinical evidence of debilitating hip pain, limited range of motion, and radiographic changes characteristic of severe hip joint osteoarthritis. Exclusion criteria included previous hip and/or spinal fusion or instrumentation surgery. All patients were clinically assessed by an independent internal medicine physician including history, physical examination, and functional scores preoperatively as well as 3 months post-THR using standard validated outcome measures as described above.
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Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S
RESULTS: Both hip pain VAS scores and Harris hip scores were significantly better after THR. Mean hip pain VAS scores were 7.08 before and 2.52 after THR surgery (p!.01). Harris hip scores were 45.74 before and 81.8 after the surgery (p!.01). Both low back pain VAS scores, as well as Oswestry spinal disability scores were significantly better after total hip replacement surgery. Mean low back pain VAS scores were 5.04 before and 3.68 after THR surgery (p5.013). Oswestry spinal disability scores were 36.72 before and 24.08 after total hip replacement surgery (p5.02). CONCLUSIONS: Low back pain was alleviated and spinal functional assessment indexes were significantly improved after total hip replacement surgery. This study, while pointing to the well known clinical association between hip and spine pathology, is among the first studies that demonstrates the clinical benefits total hip replacement surgery has upon back pain. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.085
10:14 63. Decompression and Instrumented Fusion for Management of Degenerative Lumbar Scoliosis Christopher Furey1, Sanford Emery2; 1Case Western Reserve University, Cleveland, OH, USA; 2West Virginia University School of Medicine, Morgantown, WV, USA BACKGROUND CONTEXT: Surgical management of adult degenerative scoliosis is a challenging problem with several different options available to the surgeon. PURPOSE: To assess the long-term efficacy of decompression and fusion employing pedicle screw instrumentation and iliac crest bone grafting in the treatment of degenerative scoliosis, with special attention to the nature and frequency of postoperative complications and the need for re-operation. STUDY DESIGN/SETTING: A retrospective analysis of clinical and radiographic outcomes. PATIENT SAMPLE: 42 adults (32 women and 10 men). Six patients had prior a lumbar decompression, although none had prior fusion. OUTCOME MEASURES: Specific queries regarding relief of back pain and leg pain, improvement in quality of life, satisfaction of preoperative expectations, and willingness to repeat the same procedure in hindsight. Plain radiograpghs in each case and CT scan if there was concern for pseudarthrosis. METHODS: All levels with spinal stenosis were decompressed including bilateral foraminotomies. All levels decompressed were fused as were any levels with lateral listhesis greater than 6 millimeters. The proximal extent of the fusion was at the lowest neutral vertebrae in the upper lumbar or lower thoracic spine. Fusion was extended to the sacrum only if an L5S1 spondylolisthesis was present (6 cases), but otherwise was stopped at L5. Average follow-up was 4.2 years (range 2.0–8.4 years). RESULTS: Relief of leg pain was excellent in 83%, good in 12%, fair or poor in 5%. Relief of back pain was excellent in 55%, good in 33%, fair or poor in 12%. 86% of patients felt there was improvement in their lifestyle postoperatively. 81% of patients felt their preoperative expectations had been met or exceeded. Posterolateral fusion was noted to be solid on plain radiographs by 6 months in 86% and marginal in 10%. There were two cases (4%) with pseudarthrosis. Positive outcomes were not significantly affected by number of levels fused or extension of fusion into the thoracic spine proximally or to the sacrum distally. Improvement in sagittal balance as measured on pre- and postoperative radiographs did not correlate with a favorable outcome. Presence of solid fusion did correlate with a favorable outcome. Eight patients (19%) required further surgery. Two patients (4%) with pseudarthrosis required revision instrumented fusion, two patients (4%) with early postoperative infections required surgical washouts with preservation of
instrumentation. Two patients (4%) had elective removal of painful instrumentation after 1 year. Two patients (4%) developed proximal junctional kyphosis requiring extension of fusion into the lower thoracic spine. CONCLUSIONS: Posterior decompression and fusion with pedicle screw instrumentation and iliac crest grafting is an effective treatment for adult degenerative scoliosis. Relief of leg pain is the most predictable outcome, although most patients achieve satisfactory relief of back pain as well. This surgical option is aggressive for older patients, with potential for significant complications and thus should be reserved for those patients who have failed conservative management and who are suitable medical candidates. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.086
10:20 64. Neurologic Complications of Pedicle Subtraction Osteotomy: A Ten-Year Review Jacob Buchowski, MD, MS1, Craig Kuhns, MD1, Ronald Lehman, Jr., MD2, Yongjung Kim, MD1, Lawrence Lenke, MD1, Keith Bridwell, MD1; 1 Washington University in St. Louis, St. Louis, MO, USA; 2Walter Reed Army Medical Center, Washington, DC, USA BACKGROUND CONTEXT: Pedicle subtraction osteotomy (PSO), which is performed by resecting the posterior elements, pedicles, and vertebral body through a posterior approach, is frequently used to correct fixed sagittal imbalance creating approximately 30 of lordosis at the level of the osteotomy. This is a technically demanding procedure and can be fraught with complications. Nevertheless, no reports of neurologic complications after PSOs are available in the peer-reviewed literature. PURPOSE: The objectives of this study were to evaluate intra- and postoperative neurologic deficits after PSOs, to determine the risk factors associated with the development of a neurologic complication after PSO, to examine treatment strategies, and to analyze patient outcome. STUDY DESIGN/SETTING: A retrospective cohort study. PATIENT SAMPLE: Adult patients with fixed sagittal imbalance who underwent a pedicle subtraction osteotomy at a single tertiary referral spine center. OUTCOME MEASURES: Radiographic parameters and clinical outcome measures. METHODS: A total of 114 consecutive patients (84 women and 28 men) with an average age of 54.7613.9 years treated over a 10-year period (1995-2005) with a pedicle subtraction osteotomy for fixed sagittal imbalance were evaluated. The medical records were reviewed and intraoperative electrophysiologic data were analyzed. Radiographic analysis including assessment of thoracic kyphosis, lumbar lordosis, as well as sagittal and coronal balance was performed. RESULTS: A total of 114 pedicle subtraction osteotomies were performed. After surgery, thoracic kyphosis increased from 28.2618.6 to 35.4614.7 (p!.012). Similarly, lumbar lordosis increased from (-16.3)619.5 to (-50.2)615.2 (p!.001). Sagittal balance improved from 137672 mm preoperatively to 21652 mm postoperatively (p!.001). The incidence of intra- and postoperative neurologic deficit was 10.5% (12 of 114 patients). Neurologic deficits were found intraoperatively during a Stagnara wake-up test in three patients, immediately postoperatively in the operating room suite in four patients, and in a delayed manner in the remaining five patients. Although triggered EMGs were not used in all patients, electrophysiologic testing did not detect the deficit in any of the patients. Deficits were always unilateral and usually did not correspond to the level of the osteotomy. In nine patients surgical intervention consisting of central enlargement and further decompression was required. Four patients had weakness of multiple muscle groups. Neurologic deficits included weakness of: tibialis anterior (7 patients), quadriceps (5 patients), extensor hallucis longus (3 patients), flexor hallucis longus (1 patient), and cauda