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Single-Level Lateral Lumbar Interbody Fusion for the Treatment of Adjacent Segment Disease: A Retrospective Two-Center Study
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Proceedings of the NASS 29th Annual Meeting / The Spine Journal 14 (2014) 1S–183S
P127. Can Low Dose rhBMP-2 Replace Iliac Crest Bone Graft in Achieving Successful Fusion in Adults with a Long Fusion to the Sacrum? Sachin Gupta1, Guarav S. Gulsin, MD2, Floreana Naef, MD3, Kareem J. Kebaish4, Khaled M. Kebaish, MD3, Munish C. Gupta, MD5; 1 Carmichael, CA, US; 2Aberdeen Royal Infirmary, Aberdeen, UK; 3 Baltimore, MD, US; 4Oakton, VA, US; 5University of California Davis Orthopaedic Surgery, Sacramento, CA, US BACKGROUND CONTEXT: BMP has been effective as a bone graft replacement in spinal fusion. Low dose BMP (LDBMP) has been used to treat adult deformities instead of the published large doses of 20mg per level. There is a paucity of literature describing the efficacy of low dose rh-BMP-2 (LDBMP) in multilevel adult deformity patients. PURPOSE: This study compares the efficacy and complication rates of LDBMP to iliac crest in long fusions in adult deformity patients. STUDY DESIGN/SETTING: Retrospective review. PATIENT SAMPLE: 46 patients with LDBMP and 43 with ICBG with adequate radiographic and clinical follow-up were studied. OUTCOME MEASURES: Radiographic analysis for nonunions and clinical results analyzed for signs and symptoms. METHODS: A retrospective review of patients with minimum 5-level fusions treated with LDBMP or ICBG was studied from two centers. One center used LDBMP and the other ICBG. Radiographic analysis and chart review was performed. Minimum follow-up was 2 years. RESULTS: 46 LDBMP and 43 ICBG patients had adequate radiographic and clinical follow-up. The mean age was 63 years for both groups. The avg follow-up was 25 months for LDBMP and 26 months for ICBG. The total amount of rh-BMP-2 used in each patient was 1-3 large kits (12mg/kit). The average amount of rh-BMP-2 used was 18.52 mg (avg 1.78 mg/ level). The mean blood loss in the LDBMP was 2848 ml and ICBG was 3471 ml. The average operative time was 618 min in LDBMP group and 506 min in ICBG group. The average levels fused using ICBG was 10.72 levels and using LDBMP group was 11.63 levels. The average levels fused anteriorly was 4.75. All patients had supplementation with allograft as an extender in addition to local bone. All patients were fused to the sacrum. There were 3 nonunions with ICBG and 0 nonunions with LDBMP. The ICBG overall complication rate of 45% including 21% junctional breakdown, 13.75% cardiac, 10% neurologic, 6.25% respiratory, 1.25% gastrointestinal, 7.5% urological and 7.5% dermatological. Total revision rate was 11.6%. The overall complication rate with LDBMP was 33% including 23% junctional breakdown, 6.52% cardiac, 0% neurologic, 6.52% respiratory, 4.34% gastrointestinal, 2.17% urological, with a total revision rate of 15.2 % percent. CONCLUSIONS: Low dose rh-BMP-2 as a bone graft replacement can be successfully used in long fusion to the pelvis in adult deformity patients. The efficacy of fusion, complication rate and reoperation rates were similar. FDA DEVICE/DRUG STATUS: bmp (Not approved for this indication) http://dx.doi.org/10.1016/j.spinee.2014.08.381
P128. A Comparative Analysis of Lumbosacral Fixation Strengths: What is Best in a Long Fusion? Emily M. Lindley, PhD1, Christopher Kleck, MD2, Damian Illing3, Vikas V. Patel, MD4, Cameron Barton2, Devin Razavi-Shearer, BA1, Christopher M. Cain, MD, FRACS5, Evalina L. Burger, MD6; 1University of Colorado Denver, Aurora, CO, US; 2University of Colorado, Aurora, CO, US; 3 University of Colorado Anschutz Medical Campus, Aurora, CO, US; 4 Denver, CO, US; 5Aurora, CO, US; 6Department of Orthopaedics, UC Denver, Aurora, CO, US BACKGROUND CONTEXT: Pseudoarthrosis, sacral stress fractures, and instrumentation failure are all complications observed in long posterior lumbar and thoracolumbar fixation constructs. The long lever arm of the
spine construct creates stress across the lumbosacral region. Various techniques have been developed to decrease the rate of pseudoarthrosis, including iliac bolts, anterior L5-S1 interbody cages, and anterior column fixation with interbody devices. While studies have been performed to support these methods in clinical use, there are limited data comparing various fixation methods biomechanically. PURPOSE: This study was designed to evaluate the biomechanical properties of anterior and posterior spinal fusion constructs using a combination of interbody devices with or without screws, anterior fixation and iliac bolts. STUDY DESIGN/SETTING: Biomechanical evaluation of 12 fresh frozen cadavers. OUTCOME MEASURES: Strain gauges were used to measure strain on the rods between L5-S1, on connectors between S1 and iliac bolts, and on S1 screws. METHODS: 12 fresh frozen cadavers were instrumented from L2-S1. Each specimen was sequentially tested in flexion, extension and rotation with different construct configurations, including interbody devices and iliac bolts. RESULTS: Extension: Overall, the addition of anterior and posterior instrumentation significantly decreased strain on the S1 screw, L5-S1 rod, and S1-iliac bolt connector. Flexion: Compared to posterior fusion without iliac bolts, strain at the S1 screw increased with iliac bolts, cages placed by a TLIF approach, and cages placed by an anterior approach. However, the strain decreased with the placement of an anterior cage and iliac bolts or an ATB. Rotation: Compared to posterior instrumentation with iliac bolts, strain on the S1 screw significantly decreased when instrumentation was changed to a SynFix implant and iliac bolts were removed. A significant decrease at the S1 screw was seen when the ATB was used without bolts in the setting of the SynFix implant. CONCLUSIONS: While the results only present significant findings, several other trends were identified. The results indicate that flexion increases strain at the S1 screw and L5-S1 rod. This appears to increase with the use of anteriorly placed interbody devices or iliac bolts, and can be mitigated with the combination of iliac bolts and interbody cages. It appears iliac bolts actually increase the strain in flexion greater than interbody cages alone. When evaluating extension-based activities, anteriorly placed devices appear to decrease strain when compared to iliac bolts, but a combination of techniques provides the greatest decrease. In rotation, anterior interbody constructs appear to increase S1 strain compared to iliac bolts, but again, a combination of bolts and anterior devices led to decreased strain. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.382
P129. Single-Level Lateral Lumbar Interbody Fusion for the Treatment of Adjacent Segment Disease: A Retrospective Two-Center Study Alexander Aichmair, MD1, Marjan Alimi2, Alexander P. Hughes, MD3, Andrew A. Sama, MD3, Jerry Y. Du3, Roger Hartl, MD4, Frank P. Cammisa, Jr., MD3, Federico P. Girardi, MD3; 1Vienna, Austria; 2New York, NY, US; 3Hospital for Special Surgery, New York, NY, US; 4NY Presbyterian Hospital - Weill Cornell, New York, NY, US BACKGROUND CONTEXT: While there is a plethora of literature on adjacent segment disease (ASD) following traditional arthrodesis techniques, the data on ASD following lateral lumbar interbody fusion (LLIF) is limited. Vice versa, the surgical outcome after LLIF for the treatment of ASD remains to be elucidated. PURPOSE: To assess the surgical outcome and reoperation rate in patients who underwent single-level LLIF for adjacent segment disease (ASD). STUDY DESIGN/SETTING: Retrospective case series.
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
Proceedings of the NASS 29th Annual Meeting / The Spine Journal 14 (2014) 1S–183S OUTCOME MEASURES: Radiographic outcome parameters: segmental lordosis, segmental coronal angulation, and intervertebral height. Clinical outcome parameters: VAS back pain, VAS leg pain, re-operation rate. METHODS: Patients who had undergone single-level LLIF for ASD at two institutions (03/2006-04/2012) were included, and the medical records, operative reports, radiographic imaging studies, and office records retrospectively reviewed. RESULTS: Out of 523 LLIF patients, 10.1% (n553) met the inclusion criteria of the present study, and were postoperatively followed for 16.169.7 months (range: 5-44). When comparing the preoperative setting with both the first and most recent follow-up, LLIF resulted in a statistically significant reduction in back pain (p!0.001, and p!0.001, respectively) and leg pain (p!0.001, and p!0.001, respectively), increase in segmental lordosis (p50.002, and p50.011, respectively), decrease in segmental coronal angulation (p!0.001, and p50.002, respectively), and increase in intervertebral height (p!0.001, and p!0.001, respectively) at the surgical level. The reoperation rate related to the LLIF procedure was 20.8% (11/53), which was performed after an average of 14.6610.1 months (range: 3.3-31.0). Nine out of 11 patients (81.8%) in the reoperation sub-cohort underwent standalone LLIF, whereas only 24 out of 42 patients (57.1%) without a reoperation underwent a standalone procedure (p50.123). CONCLUSIONS: LLIF is an effective surgical treatment option for ASD both with regard to the clinical and the radiographic outcome in a large proportion of cases. Although stand-alone LLIF is associated with a narrower spectrum of adverse effects, when compared to circumferential fusion, supplemental posterior segmental instrumentation may be necessary to increase segmental stability. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.383
P130. The Effect of Surgical Correction for Increased Cobb Angle and Sagittal Contour on Thoracic Volume in Adolescent Idiopathic Scoliosis Charles Gerald T. Ledonio, MD1, Jennifer Wozniczka2, David W. Polly, Jr., MD3, Ben Rosenstein, BS1, David J. Nuckley, PhD2; 1Minneapolis, MN, US; 2University of Minnesota, Minneapolis, MN, US; 3University of Minnesota Physicians, Minneapolis, MN, US BACKGROUND CONTEXT: Scoliosis may have detrimental effects on pulmonary function, as measured by pulmonary function tests (PFTs). Early results using computer modeling for thoracic volume has shown a correlation between decreased volume and severe pulmonary compromise as measured by PFTs. Thoracic volume changes based on varying Cobb angle and sagittal alignment are not well understood; additionally, changes before and after surgery are not well defined. PURPOSE: This study examines the pre- and postoperative effect of sagittal contour and Cobb angle on thoracic volume in patients with adolescent idiopathic scoliosis (AIS), using 3D computer modeling to obtain volume measurements from 2D radiographs. STUDY DESIGN/SETTING: Retrospective chart review. PATIENT SAMPLE: Nine adolescents with AIS enrolled in a multicenter database who had undergone corrective spinal fusion surgery. OUTCOME MEASURES: Pre- and postoperative effect of sagittal contour and Cobb angle on thoracic volume. METHODS: Coronal and sagittal radiographs were reviewed. All patients had Lenke type 1 curves with increasing coronal Cobb angles starting at 50 , and neutral or hypokyphotic sagittal alignment of T5-T12. Blender 2.63aÔ software was used to construct pre- and postoperative 3D computational thoracic models by deforming the models to match the calibrated radiographs. Validation of this technique against CT has shown measurement differences of 3.8% 6 2.4%. RESULTS: Preoperative modeling showed a moderate inverse correlation between thoracic volume and Cobb angle in samples with neutral sagittal
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contour (r 5 –0.629), a weak inverse correlation with hypokyphotic sagittal contour (r 5 –0.458), and no correlation with sagittal angle. Postoperatively, Cobb angle was significantly reduced (p!0.001) and thoracic volume significantly increased by a mean of 567 cc (p!0.001). Additionally, smaller baseline volumes showed greater postoperative change (r 5 –0.86). There was a weak correlation between preoperative Cobb angle and postoperative change in volume (r 5 0.45). CONCLUSIONS: Despite the small sample size, preoperatively increased Cobb angle correlated with smaller thoracic volumes in patients with neutral or hypokyphotic sagittal contour. This provides pilot data suggesting the expected correlations. Postoperative models showed increased thoracic volume in all patients, with smaller preoperative volumes and increased Cobb angle associated with larger postoperative change. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.384
P131. Patient Reported Outcome Measures Collected via Telephonic Interviews versus Self-Administered Forms after Lumbar Spine Surgery: Does Data Collection Methodology Make a Difference? Scott L. Parker, MD1, Saniya S. Godil, MD2, Kristin Archer, PhD, DPT2, Susan Vanston3, Stephen Wegener, PhD4, Clinton J. Devin, MD3; 1 Vanderbilt University, Nashville, TN, US; 2Vanderbilt University Medical Center, Nashville, TN, US; 3Nashville, TN, US; 4Johns Hopkins, Baltimore, MD, US BACKGROUND CONTEXT: As there is a growing demand to measure the real-world effectiveness and value of care, prospective registries incorporating several validated patient reported outcomes (PROs) have emerged as a feasible way. Most of the PROs have been commonly self-administered, and although approved for telephonic interviews, none of the studies have compared the effect of mode of administration on the validity of these PROs. PURPOSE: To determine the correlation of PRO scores and compare the validity of the PROs collected after lumbar spine surgery via telephonic interviews versus self-administration during clinic visit. STUDY DESIGN/SETTING: Prospective comparison cohort study. PATIENT SAMPLE: Consecutive series of patients undergoing lumbar spine surgery at a single institution. OUTCOME MEASURES: Numeric Rating Scale (NRS for back (BP) and leg (LP) pain, Oswestry Disability Index (ODI), Short Form-12 mental (SF-12 MCS) and physical (SF-12 PCS) component scores, Health Transition Index (HTI) of SF-36, NASS satisfaction METHODS: All patients undergoing lumbar spine surgery at a single medical institution were enrolled in our longitudinal prospective spine registry. Baseline and 3-month PROs on pain, disability and quality of life were collected. Three-month PROs were collected via telephonic interviews conducted by an independent researcher not involved in patient care, as well as via self-administered forms during clinic visit. PROs in these two groups were compared to see if the scores collected via different methods correlate well and whether it affects the validity and responsiveness of these PROs. RESULTS: A total of 91 patients with 3-month follow-up were included in the study. There was no significant difference in the PRO scores at 3months (back pain, leg pain, ODI and SF-12 MCS) between the two methods except SF-12 PCS (p50.04). There was strong correlation between back pain (0.71) and ODI scores (0.80); however, leg pain (0.64), SF-12 PCS (0.65) and SF-12 MCS (0.53) had moderate correlations. Health Transition Index (0.47) and patient satisfaction (0.44) had low correlations. The responsiveness of the PROs (Area under the curve) varied significantly between the two methods and the choice of anchor (HTI vs. Patient satisfaction). CONCLUSIONS: Patients reported outcomes in patients undergoing spine surgery collected via telephonic interview vs self-administration
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
Proceedings of the NASS 29th Annual Meeting / The Spine Journal 14 (2014) 1S–183S
P127. Can Low Dose rhBMP-2 Replace Iliac Crest Bone Graft in Achieving Successful Fusion in Adults with a Long Fusion to the Sacrum? Sachin Gupta1, Guarav S. Gulsin, MD2, Floreana Naef, MD3, Kareem J. Kebaish4, Khaled M. Kebaish, MD3, Munish C. Gupta, MD5; 1 Carmichael, CA, US; 2Aberdeen Royal Infirmary, Aberdeen, UK; 3 Baltimore, MD, US; 4Oakton, VA, US; 5University of California Davis Orthopaedic Surgery, Sacramento, CA, US BACKGROUND CONTEXT: BMP has been effective as a bone graft replacement in spinal fusion. Low dose BMP (LDBMP) has been used to treat adult deformities instead of the published large doses of 20mg per level. There is a paucity of literature describing the efficacy of low dose rh-BMP-2 (LDBMP) in multilevel adult deformity patients. PURPOSE: This study compares the efficacy and complication rates of LDBMP to iliac crest in long fusions in adult deformity patients. STUDY DESIGN/SETTING: Retrospective review. PATIENT SAMPLE: 46 patients with LDBMP and 43 with ICBG with adequate radiographic and clinical follow-up were studied. OUTCOME MEASURES: Radiographic analysis for nonunions and clinical results analyzed for signs and symptoms. METHODS: A retrospective review of patients with minimum 5-level fusions treated with LDBMP or ICBG was studied from two centers. One center used LDBMP and the other ICBG. Radiographic analysis and chart review was performed. Minimum follow-up was 2 years. RESULTS: 46 LDBMP and 43 ICBG patients had adequate radiographic and clinical follow-up. The mean age was 63 years for both groups. The avg follow-up was 25 months for LDBMP and 26 months for ICBG. The total amount of rh-BMP-2 used in each patient was 1-3 large kits (12mg/kit). The average amount of rh-BMP-2 used was 18.52 mg (avg 1.78 mg/ level). The mean blood loss in the LDBMP was 2848 ml and ICBG was 3471 ml. The average operative time was 618 min in LDBMP group and 506 min in ICBG group. The average levels fused using ICBG was 10.72 levels and using LDBMP group was 11.63 levels. The average levels fused anteriorly was 4.75. All patients had supplementation with allograft as an extender in addition to local bone. All patients were fused to the sacrum. There were 3 nonunions with ICBG and 0 nonunions with LDBMP. The ICBG overall complication rate of 45% including 21% junctional breakdown, 13.75% cardiac, 10% neurologic, 6.25% respiratory, 1.25% gastrointestinal, 7.5% urological and 7.5% dermatological. Total revision rate was 11.6%. The overall complication rate with LDBMP was 33% including 23% junctional breakdown, 6.52% cardiac, 0% neurologic, 6.52% respiratory, 4.34% gastrointestinal, 2.17% urological, with a total revision rate of 15.2 % percent. CONCLUSIONS: Low dose rh-BMP-2 as a bone graft replacement can be successfully used in long fusion to the pelvis in adult deformity patients. The efficacy of fusion, complication rate and reoperation rates were similar. FDA DEVICE/DRUG STATUS: bmp (Not approved for this indication) http://dx.doi.org/10.1016/j.spinee.2014.08.381
P128. A Comparative Analysis of Lumbosacral Fixation Strengths: What is Best in a Long Fusion? Emily M. Lindley, PhD1, Christopher Kleck, MD2, Damian Illing3, Vikas V. Patel, MD4, Cameron Barton2, Devin Razavi-Shearer, BA1, Christopher M. Cain, MD, FRACS5, Evalina L. Burger, MD6; 1University of Colorado Denver, Aurora, CO, US; 2University of Colorado, Aurora, CO, US; 3 University of Colorado Anschutz Medical Campus, Aurora, CO, US; 4 Denver, CO, US; 5Aurora, CO, US; 6Department of Orthopaedics, UC Denver, Aurora, CO, US BACKGROUND CONTEXT: Pseudoarthrosis, sacral stress fractures, and instrumentation failure are all complications observed in long posterior lumbar and thoracolumbar fixation constructs. The long lever arm of the
spine construct creates stress across the lumbosacral region. Various techniques have been developed to decrease the rate of pseudoarthrosis, including iliac bolts, anterior L5-S1 interbody cages, and anterior column fixation with interbody devices. While studies have been performed to support these methods in clinical use, there are limited data comparing various fixation methods biomechanically. PURPOSE: This study was designed to evaluate the biomechanical properties of anterior and posterior spinal fusion constructs using a combination of interbody devices with or without screws, anterior fixation and iliac bolts. STUDY DESIGN/SETTING: Biomechanical evaluation of 12 fresh frozen cadavers. OUTCOME MEASURES: Strain gauges were used to measure strain on the rods between L5-S1, on connectors between S1 and iliac bolts, and on S1 screws. METHODS: 12 fresh frozen cadavers were instrumented from L2-S1. Each specimen was sequentially tested in flexion, extension and rotation with different construct configurations, including interbody devices and iliac bolts. RESULTS: Extension: Overall, the addition of anterior and posterior instrumentation significantly decreased strain on the S1 screw, L5-S1 rod, and S1-iliac bolt connector. Flexion: Compared to posterior fusion without iliac bolts, strain at the S1 screw increased with iliac bolts, cages placed by a TLIF approach, and cages placed by an anterior approach. However, the strain decreased with the placement of an anterior cage and iliac bolts or an ATB. Rotation: Compared to posterior instrumentation with iliac bolts, strain on the S1 screw significantly decreased when instrumentation was changed to a SynFix implant and iliac bolts were removed. A significant decrease at the S1 screw was seen when the ATB was used without bolts in the setting of the SynFix implant. CONCLUSIONS: While the results only present significant findings, several other trends were identified. The results indicate that flexion increases strain at the S1 screw and L5-S1 rod. This appears to increase with the use of anteriorly placed interbody devices or iliac bolts, and can be mitigated with the combination of iliac bolts and interbody cages. It appears iliac bolts actually increase the strain in flexion greater than interbody cages alone. When evaluating extension-based activities, anteriorly placed devices appear to decrease strain when compared to iliac bolts, but a combination of techniques provides the greatest decrease. In rotation, anterior interbody constructs appear to increase S1 strain compared to iliac bolts, but again, a combination of bolts and anterior devices led to decreased strain. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.382
P129. Single-Level Lateral Lumbar Interbody Fusion for the Treatment of Adjacent Segment Disease: A Retrospective Two-Center Study Alexander Aichmair, MD1, Marjan Alimi2, Alexander P. Hughes, MD3, Andrew A. Sama, MD3, Jerry Y. Du3, Roger Hartl, MD4, Frank P. Cammisa, Jr., MD3, Federico P. Girardi, MD3; 1Vienna, Austria; 2New York, NY, US; 3Hospital for Special Surgery, New York, NY, US; 4NY Presbyterian Hospital - Weill Cornell, New York, NY, US BACKGROUND CONTEXT: While there is a plethora of literature on adjacent segment disease (ASD) following traditional arthrodesis techniques, the data on ASD following lateral lumbar interbody fusion (LLIF) is limited. Vice versa, the surgical outcome after LLIF for the treatment of ASD remains to be elucidated. PURPOSE: To assess the surgical outcome and reoperation rate in patients who underwent single-level LLIF for adjacent segment disease (ASD). STUDY DESIGN/SETTING: Retrospective case series.
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
Proceedings of the NASS 29th Annual Meeting / The Spine Journal 14 (2014) 1S–183S OUTCOME MEASURES: Radiographic outcome parameters: segmental lordosis, segmental coronal angulation, and intervertebral height. Clinical outcome parameters: VAS back pain, VAS leg pain, re-operation rate. METHODS: Patients who had undergone single-level LLIF for ASD at two institutions (03/2006-04/2012) were included, and the medical records, operative reports, radiographic imaging studies, and office records retrospectively reviewed. RESULTS: Out of 523 LLIF patients, 10.1% (n553) met the inclusion criteria of the present study, and were postoperatively followed for 16.169.7 months (range: 5-44). When comparing the preoperative setting with both the first and most recent follow-up, LLIF resulted in a statistically significant reduction in back pain (p!0.001, and p!0.001, respectively) and leg pain (p!0.001, and p!0.001, respectively), increase in segmental lordosis (p50.002, and p50.011, respectively), decrease in segmental coronal angulation (p!0.001, and p50.002, respectively), and increase in intervertebral height (p!0.001, and p!0.001, respectively) at the surgical level. The reoperation rate related to the LLIF procedure was 20.8% (11/53), which was performed after an average of 14.6610.1 months (range: 3.3-31.0). Nine out of 11 patients (81.8%) in the reoperation sub-cohort underwent standalone LLIF, whereas only 24 out of 42 patients (57.1%) without a reoperation underwent a standalone procedure (p50.123). CONCLUSIONS: LLIF is an effective surgical treatment option for ASD both with regard to the clinical and the radiographic outcome in a large proportion of cases. Although stand-alone LLIF is associated with a narrower spectrum of adverse effects, when compared to circumferential fusion, supplemental posterior segmental instrumentation may be necessary to increase segmental stability. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.383
P130. The Effect of Surgical Correction for Increased Cobb Angle and Sagittal Contour on Thoracic Volume in Adolescent Idiopathic Scoliosis Charles Gerald T. Ledonio, MD1, Jennifer Wozniczka2, David W. Polly, Jr., MD3, Ben Rosenstein, BS1, David J. Nuckley, PhD2; 1Minneapolis, MN, US; 2University of Minnesota, Minneapolis, MN, US; 3University of Minnesota Physicians, Minneapolis, MN, US BACKGROUND CONTEXT: Scoliosis may have detrimental effects on pulmonary function, as measured by pulmonary function tests (PFTs). Early results using computer modeling for thoracic volume has shown a correlation between decreased volume and severe pulmonary compromise as measured by PFTs. Thoracic volume changes based on varying Cobb angle and sagittal alignment are not well understood; additionally, changes before and after surgery are not well defined. PURPOSE: This study examines the pre- and postoperative effect of sagittal contour and Cobb angle on thoracic volume in patients with adolescent idiopathic scoliosis (AIS), using 3D computer modeling to obtain volume measurements from 2D radiographs. STUDY DESIGN/SETTING: Retrospective chart review. PATIENT SAMPLE: Nine adolescents with AIS enrolled in a multicenter database who had undergone corrective spinal fusion surgery. OUTCOME MEASURES: Pre- and postoperative effect of sagittal contour and Cobb angle on thoracic volume. METHODS: Coronal and sagittal radiographs were reviewed. All patients had Lenke type 1 curves with increasing coronal Cobb angles starting at 50 , and neutral or hypokyphotic sagittal alignment of T5-T12. Blender 2.63aÔ software was used to construct pre- and postoperative 3D computational thoracic models by deforming the models to match the calibrated radiographs. Validation of this technique against CT has shown measurement differences of 3.8% 6 2.4%. RESULTS: Preoperative modeling showed a moderate inverse correlation between thoracic volume and Cobb angle in samples with neutral sagittal
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contour (r 5 –0.629), a weak inverse correlation with hypokyphotic sagittal contour (r 5 –0.458), and no correlation with sagittal angle. Postoperatively, Cobb angle was significantly reduced (p!0.001) and thoracic volume significantly increased by a mean of 567 cc (p!0.001). Additionally, smaller baseline volumes showed greater postoperative change (r 5 –0.86). There was a weak correlation between preoperative Cobb angle and postoperative change in volume (r 5 0.45). CONCLUSIONS: Despite the small sample size, preoperatively increased Cobb angle correlated with smaller thoracic volumes in patients with neutral or hypokyphotic sagittal contour. This provides pilot data suggesting the expected correlations. Postoperative models showed increased thoracic volume in all patients, with smaller preoperative volumes and increased Cobb angle associated with larger postoperative change. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.384
P131. Patient Reported Outcome Measures Collected via Telephonic Interviews versus Self-Administered Forms after Lumbar Spine Surgery: Does Data Collection Methodology Make a Difference? Scott L. Parker, MD1, Saniya S. Godil, MD2, Kristin Archer, PhD, DPT2, Susan Vanston3, Stephen Wegener, PhD4, Clinton J. Devin, MD3; 1 Vanderbilt University, Nashville, TN, US; 2Vanderbilt University Medical Center, Nashville, TN, US; 3Nashville, TN, US; 4Johns Hopkins, Baltimore, MD, US BACKGROUND CONTEXT: As there is a growing demand to measure the real-world effectiveness and value of care, prospective registries incorporating several validated patient reported outcomes (PROs) have emerged as a feasible way. Most of the PROs have been commonly self-administered, and although approved for telephonic interviews, none of the studies have compared the effect of mode of administration on the validity of these PROs. PURPOSE: To determine the correlation of PRO scores and compare the validity of the PROs collected after lumbar spine surgery via telephonic interviews versus self-administration during clinic visit. STUDY DESIGN/SETTING: Prospective comparison cohort study. PATIENT SAMPLE: Consecutive series of patients undergoing lumbar spine surgery at a single institution. OUTCOME MEASURES: Numeric Rating Scale (NRS for back (BP) and leg (LP) pain, Oswestry Disability Index (ODI), Short Form-12 mental (SF-12 MCS) and physical (SF-12 PCS) component scores, Health Transition Index (HTI) of SF-36, NASS satisfaction METHODS: All patients undergoing lumbar spine surgery at a single medical institution were enrolled in our longitudinal prospective spine registry. Baseline and 3-month PROs on pain, disability and quality of life were collected. Three-month PROs were collected via telephonic interviews conducted by an independent researcher not involved in patient care, as well as via self-administered forms during clinic visit. PROs in these two groups were compared to see if the scores collected via different methods correlate well and whether it affects the validity and responsiveness of these PROs. RESULTS: A total of 91 patients with 3-month follow-up were included in the study. There was no significant difference in the PRO scores at 3months (back pain, leg pain, ODI and SF-12 MCS) between the two methods except SF-12 PCS (p50.04). There was strong correlation between back pain (0.71) and ODI scores (0.80); however, leg pain (0.64), SF-12 PCS (0.65) and SF-12 MCS (0.53) had moderate correlations. Health Transition Index (0.47) and patient satisfaction (0.44) had low correlations. The responsiveness of the PROs (Area under the curve) varied significantly between the two methods and the choice of anchor (HTI vs. Patient satisfaction). CONCLUSIONS: Patients reported outcomes in patients undergoing spine surgery collected via telephonic interview vs self-administration
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.