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194. Pedicle Subtraction vs. Smith-Petersen Osteotomies for Correction of Fixed Sagittal Plane Deformities: Radiographic Outcomes in 151 Patients
Proceedings of the NASS 23rd Annual Meeting / The Spine Journal 8 (2008) 1S–191S The mean time to the first revision was 4.0 years (range 1 week–19.7 years). Of the 58 patients, the most common reasons for revision were pseudarthrosis (25/66753.7%; 25/58543.1%), curve progression (13/ 66751.9%; 13/58522.4%), infection (9/66751.3%; 9/58515.5%) and painful or prominent implants (4/66750.6%; 4/5856.9%). More rare reasons consisted of adjacent segment degeneration (3), implant failure (2), neurologic deficit (1) and coronal imbalance (1). Revision rates over the follow-up period were: 0–2 years (26/58544.8%), 2–5 years (17/ 58529.3%), 5–10 years (7/58512.1%),O10 years (8/58513.8%). CONCLUSIONS: Repeat surgical intervention following definitive spinal instrumented fusion for primary adult deformity occurs at a relatively low rate of 8.7%. The most common reasons for revision are predictable and include pseudarthrosis, proximal/distal curve progression and infection. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.230
193. Consideration of Vertebral Rotation Improves the Accuracy of Pedicle Screw Placement: A Prospective Study Using Postoperative CT Scans Adam Wollowick, MD, Beverly Thornhill, MD, Terry Amaral, MD, Alok Sharan, MD, Vishal Sarwahi, MD; Albert Einstein College of Medicine, Bronx, NY, USA BACKGROUND CONTEXT: Placement of pedicle screws using the anatomic free-hand technique requires a knowledge of complex spinal anatomy. This task is more difficult in the deformed spine. While the ideal pedicle entry point has been well described, the assessment of vertebral rotation in the axial plane is the most challenging aspect of pedicle screw placement. Previously, we found that axial rotation measurements have a direct correlation with the Nash-Moe grade. Approximately 10 degrees of vertebral rotation was found per grade. PURPOSE: To determine if consideration of vertebral rotation improves the accuracy of pedicle screw placement in the setting of pediatric spinal deformity surgery. STUDY DESIGN/ SETTING: This study is a comparison of two cohorts of pediatric spinal deformity patients. The study was performed at an academic medical center in a major metropolitan area. Post-operative CT scans were used to compare two techniques of pedicle screw placement. PATIENT SAMPLE: 52 pediatric patients (#18 years) with spinal deformity who were treated surgically using pedicle screw-based instrumentation. OUTCOME MEASURES: Incidence of misplacement of thoracic and lumbar pedicle screws in the setting of pediatric spinal deformity. METHODS: We reviewed post-operative CT scans of 52 patients with pediatric spinal deformity. Patients were divided into two groups: Group 1 had surgery between 2004 and 2006. Group 2 had surgery in 2007. All data for Group 2 was collected prospectively. In 2007, placement of pedicle screws was performed with specific consideration of the degree of rotation. This was determined pre-operatively for all instrumented levels using the Nash-Moe rotation criteria on a recumbent x-ray. Post-operative CT scans were used to determine the number of misplaced pedicle screws. Screws were considered misplaced if there was any violation of the medial or lateral cortices or if there was anterior penetrationO3mm. RESULTS: In Group 1, 501 pedicle screws were placed. 350 screws were placed in the thoracic spine and 151 in the lumbar spine. In Group 2, 521 screws were placed. 361 screws were placed in the thoracic spine and 160 in the lumbar spine. The overall incidence of misplacement in Group 1 was 10.4% compared to 3.8% in Group 2. In the thoracic spine, 13.7% of screws were misplaced in Group 1 vs. 5.6% in Group 2. In the lumbar spine, 2.7% of screws were misplaced in Group 1 vs. 0% in Group 2. All differences were statistically significant (p#0.05). CONCLUSIONS: Using the degree of vertebral rotation defined by the Nash-Moe grade to assist in the placement of pedicle screws led to a more than 50% reduction in the number of misplaced screws. The overall
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incidence of misplaced screws decreased from 10% to 4% by using a modified anatomic free-hand technique. Modifying the technique of pedicle screw placement to include consideration of vertebral rotation can decrease the incidence of misplaced screws. Improved accuracy of pedicle screw placement increases patient safety during pediatric spinal deformity surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.231
194. Pedicle Subtraction vs. Smith-Petersen Osteotomies for Correction of Fixed Sagittal Plane Deformities: Radiographic Outcomes in 151 Patients Brian Hsu, MD, Serkan Erkan, MD, Ensor Transfeldt, MD, Joseph Perra, MD, Francis Denis, MD, Timothy Garvey, MD, Manuel Pinto, MD, James Schwender, MD, Daryll Dykes, MD, PhD, John Lonstein, MD, Robert Winter, MD; Twin Cities Spine Center, Minneapolis, MN, USA BACKGROUND CONTEXT: Pedicle subtraction (PSO) and Smith Peterson (SPO) osteotomies are commonly used surgical techniques in the correction of spinal deformities, in particular the correction of sagittal plane deformity. This study compares the radiographic profile and outcomes in 151 such osteotomies, the largest series comparing 2 techniques from a single institution. PURPOSE: In this study, we compare the radiographic outcomes in 151 such osteotomies, the largest series comparing the two techniques from a single institution. PSO is a more powerful technique in correcting angular and translational components of sagittal balance parameters. While the angular correction of one level PSO is similar to 3 level SPO, the ability to correct C7 plumbline is better with PSO when compared to 3 level SPO which may be related to the level of the osteotomy. STUDY DESIGN/ SETTING: Retrospective chart and Film review. PATIENT SAMPLE: At our center, from 1985 to 2005, there have been over 800 spinal fusion operations performed that involved arthrodesis of more than 5 levels. Within this group of patients, 322 underwent spinal osteotomy procedures for a variety of indications. Included were patients having either SPO or PSO, skeletally mature and at least 2-year follow-up. OUTCOME MEASURES: SF-36, Oswestry Disability Index. METHODS: The pre-operative and post-operative radiographs were reviewed and a range of parameters were recorded. There were 151 patients identified who met the inclusion criteria. RESULTS: There were 100 (Mean age 47.3, male 40) patients who underwent SPO. 54& had an anterior procedure. Patients who had 3 or more SPO on average had greater than 10 fusion levels and had greater change in segmental kyphotic angle and sagittal balance than 1 or 2 levels. The mean segmental kyphosis correction showed significant difference between 1 and 2 level SPO (19 ) versus 3 or more SPO (36 ). There were 51 patients who underwent PSO (Ave age 50.8, Male 21). 13 patients had thoracic PSO (11/13 did not have an anterior procedure). PSO patients showed greater sagittal plane correction than 1, 2 or 3 level SPO (Mean C7 plumb line correction: SPO 15 mm per level, PSO 78 mm per level). PSO also showed greater segmental kyphosis correction compared to 1 or 2 level SPO. (SPO: 12 lordosis per level, PSO: 32 lordosis per level). CONCLUSIONS: The choice of osteotomy technique depends on the goals of surgery. SPO may be more effective in correcting segmental kyphosis, whereas PSO may restore more sagittal balance depending on the level of the osteotomy. Thoracic PSO is effective in managing segmental kyphosis without an anterior procedure. Both Smith-Petersen and Pedicle Subtraction Osteotomy surgery can provide adequate correction of sagittal plane deformities, but PSO surgery gave more correction per osteotomy for both sagittal balance and segmental kyphosis. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.232
193. Consideration of Vertebral Rotation Improves the Accuracy of Pedicle Screw Placement: A Prospective Study Using Postoperative CT Scans Adam Wollowick, MD, Beverly Thornhill, MD, Terry Amaral, MD, Alok Sharan, MD, Vishal Sarwahi, MD; Albert Einstein College of Medicine, Bronx, NY, USA BACKGROUND CONTEXT: Placement of pedicle screws using the anatomic free-hand technique requires a knowledge of complex spinal anatomy. This task is more difficult in the deformed spine. While the ideal pedicle entry point has been well described, the assessment of vertebral rotation in the axial plane is the most challenging aspect of pedicle screw placement. Previously, we found that axial rotation measurements have a direct correlation with the Nash-Moe grade. Approximately 10 degrees of vertebral rotation was found per grade. PURPOSE: To determine if consideration of vertebral rotation improves the accuracy of pedicle screw placement in the setting of pediatric spinal deformity surgery. STUDY DESIGN/ SETTING: This study is a comparison of two cohorts of pediatric spinal deformity patients. The study was performed at an academic medical center in a major metropolitan area. Post-operative CT scans were used to compare two techniques of pedicle screw placement. PATIENT SAMPLE: 52 pediatric patients (#18 years) with spinal deformity who were treated surgically using pedicle screw-based instrumentation. OUTCOME MEASURES: Incidence of misplacement of thoracic and lumbar pedicle screws in the setting of pediatric spinal deformity. METHODS: We reviewed post-operative CT scans of 52 patients with pediatric spinal deformity. Patients were divided into two groups: Group 1 had surgery between 2004 and 2006. Group 2 had surgery in 2007. All data for Group 2 was collected prospectively. In 2007, placement of pedicle screws was performed with specific consideration of the degree of rotation. This was determined pre-operatively for all instrumented levels using the Nash-Moe rotation criteria on a recumbent x-ray. Post-operative CT scans were used to determine the number of misplaced pedicle screws. Screws were considered misplaced if there was any violation of the medial or lateral cortices or if there was anterior penetrationO3mm. RESULTS: In Group 1, 501 pedicle screws were placed. 350 screws were placed in the thoracic spine and 151 in the lumbar spine. In Group 2, 521 screws were placed. 361 screws were placed in the thoracic spine and 160 in the lumbar spine. The overall incidence of misplacement in Group 1 was 10.4% compared to 3.8% in Group 2. In the thoracic spine, 13.7% of screws were misplaced in Group 1 vs. 5.6% in Group 2. In the lumbar spine, 2.7% of screws were misplaced in Group 1 vs. 0% in Group 2. All differences were statistically significant (p#0.05). CONCLUSIONS: Using the degree of vertebral rotation defined by the Nash-Moe grade to assist in the placement of pedicle screws led to a more than 50% reduction in the number of misplaced screws. The overall
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incidence of misplaced screws decreased from 10% to 4% by using a modified anatomic free-hand technique. Modifying the technique of pedicle screw placement to include consideration of vertebral rotation can decrease the incidence of misplaced screws. Improved accuracy of pedicle screw placement increases patient safety during pediatric spinal deformity surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.231
194. Pedicle Subtraction vs. Smith-Petersen Osteotomies for Correction of Fixed Sagittal Plane Deformities: Radiographic Outcomes in 151 Patients Brian Hsu, MD, Serkan Erkan, MD, Ensor Transfeldt, MD, Joseph Perra, MD, Francis Denis, MD, Timothy Garvey, MD, Manuel Pinto, MD, James Schwender, MD, Daryll Dykes, MD, PhD, John Lonstein, MD, Robert Winter, MD; Twin Cities Spine Center, Minneapolis, MN, USA BACKGROUND CONTEXT: Pedicle subtraction (PSO) and Smith Peterson (SPO) osteotomies are commonly used surgical techniques in the correction of spinal deformities, in particular the correction of sagittal plane deformity. This study compares the radiographic profile and outcomes in 151 such osteotomies, the largest series comparing 2 techniques from a single institution. PURPOSE: In this study, we compare the radiographic outcomes in 151 such osteotomies, the largest series comparing the two techniques from a single institution. PSO is a more powerful technique in correcting angular and translational components of sagittal balance parameters. While the angular correction of one level PSO is similar to 3 level SPO, the ability to correct C7 plumbline is better with PSO when compared to 3 level SPO which may be related to the level of the osteotomy. STUDY DESIGN/ SETTING: Retrospective chart and Film review. PATIENT SAMPLE: At our center, from 1985 to 2005, there have been over 800 spinal fusion operations performed that involved arthrodesis of more than 5 levels. Within this group of patients, 322 underwent spinal osteotomy procedures for a variety of indications. Included were patients having either SPO or PSO, skeletally mature and at least 2-year follow-up. OUTCOME MEASURES: SF-36, Oswestry Disability Index. METHODS: The pre-operative and post-operative radiographs were reviewed and a range of parameters were recorded. There were 151 patients identified who met the inclusion criteria. RESULTS: There were 100 (Mean age 47.3, male 40) patients who underwent SPO. 54& had an anterior procedure. Patients who had 3 or more SPO on average had greater than 10 fusion levels and had greater change in segmental kyphotic angle and sagittal balance than 1 or 2 levels. The mean segmental kyphosis correction showed significant difference between 1 and 2 level SPO (19 ) versus 3 or more SPO (36 ). There were 51 patients who underwent PSO (Ave age 50.8, Male 21). 13 patients had thoracic PSO (11/13 did not have an anterior procedure). PSO patients showed greater sagittal plane correction than 1, 2 or 3 level SPO (Mean C7 plumb line correction: SPO 15 mm per level, PSO 78 mm per level). PSO also showed greater segmental kyphosis correction compared to 1 or 2 level SPO. (SPO: 12 lordosis per level, PSO: 32 lordosis per level). CONCLUSIONS: The choice of osteotomy technique depends on the goals of surgery. SPO may be more effective in correcting segmental kyphosis, whereas PSO may restore more sagittal balance depending on the level of the osteotomy. Thoracic PSO is effective in managing segmental kyphosis without an anterior procedure. Both Smith-Petersen and Pedicle Subtraction Osteotomy surgery can provide adequate correction of sagittal plane deformities, but PSO surgery gave more correction per osteotomy for both sagittal balance and segmental kyphosis. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.232