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Comparison of Pulmonary Function in Adults Younger and Older than Age 60 Undergoing Spinal Deformity Surgery
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Proceedings of the NASS 28th Annual Meeting / The Spine Journal 13 (2013) 1S–168S
adjacent level in the fusion cohort (p50.019) at 2 years compared to CoflexÒ. CONCLUSIONS: This is the first Level 1 study to report exclusively on two-level stenosis with spondylolisthesis treated with either a motion-preserving stabilization device (CoflexÒ) or posterior spinal fusion. Our data suggests that two-level interlaminar stabilization is not only a viable alternative to 2-level fusion, but provides substantial improvements in perioperative outcomes and equal or superior clinical outcomes sustained at 2 years, while fusions exhibited hypermobility at both the superior and inferior adjacent levels. FDA DEVICE/DRUG STATUS: coflex interlaminar device (Approved for this indication). http://dx.doi.org/10.1016/j.spinee.2013.07.394
P121. Safety of Instrumentation in Vertebral Osteomyelitis Sina Pourtaheri, MD1, Arash Emami, MD2, Eiman Shafa, MD3, Mark J. Ruoff, MD4, Ki S. Hwang, MD5, Tyler N. Stewart6, Kimona Issa, MD7, Kumar G. Sinha, MD2; 1Teaneck, NJ, US; 2University Spine Center, Wayne, NJ, US; 3Saddle Brook, NJ, US; 4Orthopaedic Associates, Fair Lawn, NJ, US; 5University Place Spine Center, Wayne, NJ, US; 6New York, NY, US; 7Baltimore, MD, US BACKGROUND CONTEXT: Hardware in orthopedics is associated with increased infection rates. PURPOSE: The purpose of the study is to re-evaluate if instrumentation prevents the clearance of vertebral osteomyelitis. STUDY DESIGN/SETTING: Retrospective clinical and radiographic review PATIENT SAMPLE: 920 vertebral osteomyelitis from 2001-2011 from a single institution OUTCOME MEASURES: Clearance of the infection, length of delay of diagnosis, Nurick grade, Oswestry score, segmental kyphosis, length of hospital stay (LOS), cost of hospital admission, mortality. METHODS: A retrospective review of 920 vertebral osteomyelitis was performed. Inclusion criteria included appropriate initial imaging, lab results, evaluation by the orthopedic department, and no treatment done prior to admission at an outside institution. Chi-squared statistic and single sampled t tests were used to examine the data. Clearance of the infection was defined as normalizing of serum markers and resolution of osteomyelitis on MRI after 6 months of treatment. RESULTS: One-hundred and six patients meet the inclusion criteria: 62 men (58%), 44 women (42%), mean age 54 yrs., mean follow-up 38 months. A total of 32 instrumented cases (INST) [cervical: 14, thoracic: 8, lumbar: 10, mean age: 56, Male: Female52.2: 1] and 74 non-instrumented cases (NINST) [cervical: 9, thoracic: 20, lumbar: 46, mean age: 53, Male: Female51.2: 1]. A higher rate of the osteomyelitis cleared in the instrumented group (82%, n526) compared to the non-instrumented group (62%, n546) [OR: 2.4, CI 50.8 to 6.7; p50.08]. Long-term improvements in the Oswestry scores from the time of presentation were similar between the groups was similar: INST5from 62.9 to 49.2, NINST5from 67.4 to 45.2. Length of stay for the instrumented group (15.5 days) was significantly longer than the noninstrumented group (12 days) [p50.04], with a higher cost of hospital admission [$216,966 vs $162,173]. The mortality rate (directly related to the osteomyelitis) in the INST group (11%, n54) was similar to that of the NIST group (7%, n55). CONCLUSIONS: Instrumentation does not hinder the rate that the osteomyelitis is cleared, and subsequently instrumented cases have comparable mortality rates and improvements in Oswestry scores as non-instrumented ones. The length of stay and hospital cost is higher with instrumented cases. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2013.07.395
P122. Pulmonary Function Following Adult Spinal Deformity Surgery: Minimum Two-Year Follow-Up Ronald A. Lehman, Jr., MD1, Daniel G. Kang, MD2, Lawrence G. Lenke, MD3, Brenda A. Sides4; 1Potomac, MD, US; 2Bethesda, MD, US; 3 Washington University Medical Center Department of Orthopedic Surgery, St. Louis, MO, US; 4Washington University School of Medicine, St. Louis, MO, US BACKGROUND CONTEXT: Pulmonary function following adult spinal deformity remains uncertain. PURPOSE: We hypothesized patients with preop PFT impairment (!65% pred FEV1) and those undergoing revision surgery may be at risk for exacerbated decline in pulmonary function. STUDY DESIGN/SETTING: Retrospective review of prospectively collected data PATIENT SAMPLE: Adult spinal deformity patients. OUTCOME MEASURES: Pulmonary function tests. METHODS: Pulmonary function tests (PFTs) were prospectively collected on 164 adult spinal deformity patients (150F, 14M, avg age 45.9) undergoing surgical treatment at a single institution, with minimum twoyear follow-up (avg 2.81). There were 100 (61%) primary and 64 (39%) revision surgery patients, and the majority had posterior only surgery (77%). Radiographs for 154 patients were analyzed for main thoracic (MT) and sagittal T5-T12 (Sag) curve magnitude/correction. RESULTS: For all patients, there was a significant change in MT Cobb from 47.4 to 24.9 (avg -22.5, p50.00), and Sag Cobb from 35.5 to 30.0 (avg -5.41, p50.00). We also found a significant decline in absolute and %pred PFT, with %pred FEV1 and %pred FVC decreasing 5.26% (p50.00) and 5.74% (p50.00), respectively. A clinically significant decline ($10%pred FEV1) was observed in 27% of patients. PFT impairment increased from 14 (8%) patients preop to 23 (14%) patients after surgery, but was not statistically significant (p50.31). Interestingly, patients with preop PFT impairment had a significant improvement in absolute and %pred FEV1 after surgery compared to those without preop impairment (2.8% v -6.19%, p50.03), with no significant differences in MT/Sag curve correction between the two groups. Revision surgery patients had no difference in postop %pred PFTs; however there were significantly more patients with a clinically significant decline in PFTs [23 (35%) v 22 (22%), p50.03]. CONCLUSIONS: We performed the largest study to date evaluating pulmonary function tests (PFTs) on 164 adult deformity patients finding a significant decline in all measures of pulmonary function at two years following surgical correction. Surprisingly, there was a significant postoperative improvement in patients who had preoperative PFT impairment. Also, revision surgery more frequently results in a clinically significant decline in PFTs. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2013.07.396
P123. Comparison of Pulmonary Function in Adults Younger and Older than Age 60 Undergoing Spinal Deformity Surgery Ronald A. Lehman, Jr., MD1, Daniel G. Kang, MD2, Lawrence G. Lenke, MD3, Brenda A. Sides4; 1Potomac, MD, US; 2Bethesda, MD, US; 3 Washington University Medical Center Department of Orthopedic Surgery, St. Louis, MO, US; 4Washington University School of Medicine, St. Louis, MO, US BACKGROUND CONTEXT: The effect of age on pulmonary function remains uncertain in patients undergoing adult spinal deformity surgery. PURPOSE: The objective of this study was to determine differences in pulmonary function in adult patients who are either younger (Y) or older (O) than age 60 following spinal deformity surgery. We hypothesize that older age may further exacerbate impairment of pulmonary function following spinal deformity surgery.
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 28th Annual Meeting / The Spine Journal 13 (2013) 1S–168S
157S
STUDY DESIGN/SETTING: Retrospective review of prospectively collected data. PATIENT SAMPLE: Adult spinal deformity patients. OUTCOME MEASURES: Pulmonary function tests. METHODS: 128 consecutive adult deformity patients with idiopathic scoliosis undergoing surgical treatment were evaluated at a single institution with minimum two year follow-up. Prospectively collected PFTs, clinical records and radiographs were analyzed. RESULTS: There were 102 patients in Y group (avg age 39.3614.1 yrs) and 26 in O group (avg age 63.762.7 yrs), with similar follow-up (Y52.9 v O52.6 yrs, p50.27). There were no differences in average preop main thoracic (MT) curve magnitude (Y550.0deg, O554.8deg, p50.27); however O patients had significantly greater # of lumbar (5.9 v 4.2, p50.00), thoracic (9.1 v 7.3, p50.00), and total (15.0 v 11.5, p50.00) levels fused. We also found O patients had significantly lower absolute preop FEV1 (2.1 v 2.6L, p50.02) and FVC (2.7 v 3.3L, p50.05), but no differences in % pred PFTs. This relationship remained at two yrs, with lower absolute FEV1 (1.9 v 2.5L, p50.00) and FVC (2.5 v 3.1L, p50.00). A clinically significant decline in PFTs (greater than 10% pred FEV1) occurred in 8 (31%) O patients and 26 (25%) Y patients which was not statistically different (p50.63). We also observed preop PFT impairment (less than 65% pred FEV1) in 1 (4%) O patient, which significantly increased to 6 (23%, p50.02) O patients postoperatively, compared to Y group experiencing no change in the number of patients (n512, 12%) with PFT impairment postoperatively. CONCLUSIONS: This is the largest study to date evaluating age related reduction in PFTs. We found older patients have no significant difference in %predicted PFTs compared to younger patients postoperatively and no differences in the rate of clinically significant PFT decline ($10% pred FEV1). However, older patients more frequently (23% v 12%) experience PFT impairment (!65%pred FEV1) after spinal deformity surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
(T6-T8), using a repeated measures ANOVA with Sidak correction for multiple comparisons. RESULTS: After PSO and instrumentation with a thoracic pedicle screwrod construct, T4-T10 ROM was significantly reduced in all planes of motion from the intact condition (p!0.05). Augmentation of the longitudinal construct with either 1 or 2 TC did not significantly increase construct stability in flexion-extension and lateral bending compared to the augmented construct (pO0.05). In contrast, during axial rotation, T4-T10 ROM was reduced by 43% following addition of 2 TC (p!0.05), and was also reduced by 26% following 1 TC (pO0.05), but did not reach statistical significance. Focal segmental stability (T6-T8) at the PSO level had similar improvement in axial rotation stability following the addition of transverse connectors, with a 48% decrease in axial rotation after 2 TC (p!0.05), and addition of 1 TC decreased axial ROM by 29%, but again did not reach statistical significance (pO0.05). CONCLUSIONS: Two transverse connectors (cross links) improved torsional rigidity by 43%, with no differences in stability for all planes of motion over the use of one transverse connector. Therefore, in the setting of a PSO and long segment pedicle screw-rod construct, augmentation with at least two transverse connectors improves torsional rigidity. FDA DEVICE/DRUG STATUS: Thoracic pedicle screws (Approved for this indication).
http://dx.doi.org/10.1016/j.spinee.2013.07.397
PURPOSE: Long fusions (above L2) to the sacrum generate high stresses on the sacral screws that may lead to loosening or pseudarthrosis (Emami 2002, Weistroffer 2008). Surgical techniques to reduce strain on the sacral screws, by improving rigidity of the L5-S1 motion segment, include anterior column support, with anterior or transforaminal lumbar interbody fusion (ALIF or TLIF) and iliac fixation. The development of stand-alone anterior fixation (ALIF cages with imbedded screws L5 and S1 vertebral bodies) may serve to reduce the need for supplementary posterior pelvic fixation. We conducted a biomechanical study using a validated in-situ model to test our hypothesis that stand-alone anterior cages reduce strain on sacral screws comparably to bilateral iliac fixation. Outcome measures from testing included multi-axial compliance at the lumbo-sacral junction and strain on the S1 screws. METHODS: Seven lumbo-pelvic human cadavers (L1-full pelvis) were used for this study. Relative motion between L1-L5, L5-S1, and S1-pelvis were measured under a load-controlled pure moment up to 7.5 Nm in flexion/extension (F/E), axial rotation (AR), and lateral bending (LB). S1 pedicle screws were instrumented with strain gauges used to measuring pullout force during testing. Three different length posterior rods were fit to each specimen for progressive posterior fixation including bilateral L1-S1, bilateral L1-S1 with unilateral iliac screw, and bilateral L1-S1 with bilateral iliac screw. These constructs were tested with and without the presence of an ALIF cage at L5-S1. RESULTS: Bilateral L1-S1 posterior hardware alone and the addition of an ALIF cage reduced and F/E ROM from 6.7þ/-4.2 to 3.1þ/-1.3, in 3.3þ/-1.2 respectively which was not statistically significant. The progression of posterior fixation to uni- and bi-lateral iliac screws sequentially decreased F/E ROM to 1.2þ/-1.2 and 0.6þ/-0.6 , respectively. Observing the loads experienced on the SI screw, the addition of an ALIF cage did not reduce loading during extension motion. Progression of the fusion rods to a uni-iliac construct significantly increased extension loads on the S1 screws. The addition of an ALIF cage to bi-lateral iliac construct significantly decreased loads during flexion and insignificantly during extension
P124. Biomechanical Contribution of Transverse Connectors in the Setting of a Thoracic Pedicle Subtraction Osteotomy Ronald A. Lehman, Jr., MD1, Haines Paik, MD2, Daniel G. Kang, MD3, Robert W. Tracey, MD4, John P. Cody, MD5, Anton E. Dmitriev, PhD6; 1 Potomac, MD, US; 2Fairfax, VA, US; 3Bethesda, MD, US; 4Rockville, MD, US; 5Washington, DC, US; 6Clarksville, MD, US BACKGROUND CONTEXT: Little data is available to guide longitudinal construct planning after a pedicle subtraction osteotomy (PSO) in the thoracic spine. Previous investigations have suggested the role of transverse connectors (TC) in enhancing torsional rigidity following long segment thoracic pedicle screw-rod instrumentation. However, the biomechanical effect of augmentation with one or two TC after PSO in the thoracic spine has not been previously evaluated. PURPOSE: We investigated the biomechanical effect of augmenting a long thoracic pedicle screw-rod construct with transverse connectors after pedicle subtraction osteotomy. STUDY DESIGN/SETTING: Cadaveric biomechanical analysis. OUTCOME MEASURES: Range of motion. METHODS: Seven (7) fresh-frozen human cadaveric thoracic spines (T3T11) were prepared, maintaining all osteoligamentous structures, and intact range of motion testing was performed with non-destructive loading (66 Nm) in a six-degree-of-freedom spine simulator. The specimens were then instrumented from T4-T10 with bilateral 5.5-mm polyaxial titanium pedicle screws and 5.5-mm contoured rods, and then a PSO performed at T7. Range of motion was subsequently analyzed in the unaugmented construct, with 1 TC (T8-T9) and then 2 TC (T5-T6 and T9-T10). Range of motion (ROM) was analyzed in axial rotation, flexion-extension, and lateral bending loading planes over T4-T10 and at the PSO level
http://dx.doi.org/10.1016/j.spinee.2013.07.398
P125. Stand-Alone ALIF for Supplementation of Long Posterior Lumbosacral Fusion Constructs Jeremi M. Leasure, MS1, William Camisa, MS2, Sigurd H. Berven, MD3; 1 The Taylor Laboratories, San Francisco, CA, US; 2Taylor Collaboration, San Francisco, CA, US; 3University of California San Francisco, Department of Orthopaedic Surgery, San Francisco, CA, US
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 28th Annual Meeting / The Spine Journal 13 (2013) 1S–168S
adjacent level in the fusion cohort (p50.019) at 2 years compared to CoflexÒ. CONCLUSIONS: This is the first Level 1 study to report exclusively on two-level stenosis with spondylolisthesis treated with either a motion-preserving stabilization device (CoflexÒ) or posterior spinal fusion. Our data suggests that two-level interlaminar stabilization is not only a viable alternative to 2-level fusion, but provides substantial improvements in perioperative outcomes and equal or superior clinical outcomes sustained at 2 years, while fusions exhibited hypermobility at both the superior and inferior adjacent levels. FDA DEVICE/DRUG STATUS: coflex interlaminar device (Approved for this indication). http://dx.doi.org/10.1016/j.spinee.2013.07.394
P121. Safety of Instrumentation in Vertebral Osteomyelitis Sina Pourtaheri, MD1, Arash Emami, MD2, Eiman Shafa, MD3, Mark J. Ruoff, MD4, Ki S. Hwang, MD5, Tyler N. Stewart6, Kimona Issa, MD7, Kumar G. Sinha, MD2; 1Teaneck, NJ, US; 2University Spine Center, Wayne, NJ, US; 3Saddle Brook, NJ, US; 4Orthopaedic Associates, Fair Lawn, NJ, US; 5University Place Spine Center, Wayne, NJ, US; 6New York, NY, US; 7Baltimore, MD, US BACKGROUND CONTEXT: Hardware in orthopedics is associated with increased infection rates. PURPOSE: The purpose of the study is to re-evaluate if instrumentation prevents the clearance of vertebral osteomyelitis. STUDY DESIGN/SETTING: Retrospective clinical and radiographic review PATIENT SAMPLE: 920 vertebral osteomyelitis from 2001-2011 from a single institution OUTCOME MEASURES: Clearance of the infection, length of delay of diagnosis, Nurick grade, Oswestry score, segmental kyphosis, length of hospital stay (LOS), cost of hospital admission, mortality. METHODS: A retrospective review of 920 vertebral osteomyelitis was performed. Inclusion criteria included appropriate initial imaging, lab results, evaluation by the orthopedic department, and no treatment done prior to admission at an outside institution. Chi-squared statistic and single sampled t tests were used to examine the data. Clearance of the infection was defined as normalizing of serum markers and resolution of osteomyelitis on MRI after 6 months of treatment. RESULTS: One-hundred and six patients meet the inclusion criteria: 62 men (58%), 44 women (42%), mean age 54 yrs., mean follow-up 38 months. A total of 32 instrumented cases (INST) [cervical: 14, thoracic: 8, lumbar: 10, mean age: 56, Male: Female52.2: 1] and 74 non-instrumented cases (NINST) [cervical: 9, thoracic: 20, lumbar: 46, mean age: 53, Male: Female51.2: 1]. A higher rate of the osteomyelitis cleared in the instrumented group (82%, n526) compared to the non-instrumented group (62%, n546) [OR: 2.4, CI 50.8 to 6.7; p50.08]. Long-term improvements in the Oswestry scores from the time of presentation were similar between the groups was similar: INST5from 62.9 to 49.2, NINST5from 67.4 to 45.2. Length of stay for the instrumented group (15.5 days) was significantly longer than the noninstrumented group (12 days) [p50.04], with a higher cost of hospital admission [$216,966 vs $162,173]. The mortality rate (directly related to the osteomyelitis) in the INST group (11%, n54) was similar to that of the NIST group (7%, n55). CONCLUSIONS: Instrumentation does not hinder the rate that the osteomyelitis is cleared, and subsequently instrumented cases have comparable mortality rates and improvements in Oswestry scores as non-instrumented ones. The length of stay and hospital cost is higher with instrumented cases. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2013.07.395
P122. Pulmonary Function Following Adult Spinal Deformity Surgery: Minimum Two-Year Follow-Up Ronald A. Lehman, Jr., MD1, Daniel G. Kang, MD2, Lawrence G. Lenke, MD3, Brenda A. Sides4; 1Potomac, MD, US; 2Bethesda, MD, US; 3 Washington University Medical Center Department of Orthopedic Surgery, St. Louis, MO, US; 4Washington University School of Medicine, St. Louis, MO, US BACKGROUND CONTEXT: Pulmonary function following adult spinal deformity remains uncertain. PURPOSE: We hypothesized patients with preop PFT impairment (!65% pred FEV1) and those undergoing revision surgery may be at risk for exacerbated decline in pulmonary function. STUDY DESIGN/SETTING: Retrospective review of prospectively collected data PATIENT SAMPLE: Adult spinal deformity patients. OUTCOME MEASURES: Pulmonary function tests. METHODS: Pulmonary function tests (PFTs) were prospectively collected on 164 adult spinal deformity patients (150F, 14M, avg age 45.9) undergoing surgical treatment at a single institution, with minimum twoyear follow-up (avg 2.81). There were 100 (61%) primary and 64 (39%) revision surgery patients, and the majority had posterior only surgery (77%). Radiographs for 154 patients were analyzed for main thoracic (MT) and sagittal T5-T12 (Sag) curve magnitude/correction. RESULTS: For all patients, there was a significant change in MT Cobb from 47.4 to 24.9 (avg -22.5, p50.00), and Sag Cobb from 35.5 to 30.0 (avg -5.41, p50.00). We also found a significant decline in absolute and %pred PFT, with %pred FEV1 and %pred FVC decreasing 5.26% (p50.00) and 5.74% (p50.00), respectively. A clinically significant decline ($10%pred FEV1) was observed in 27% of patients. PFT impairment increased from 14 (8%) patients preop to 23 (14%) patients after surgery, but was not statistically significant (p50.31). Interestingly, patients with preop PFT impairment had a significant improvement in absolute and %pred FEV1 after surgery compared to those without preop impairment (2.8% v -6.19%, p50.03), with no significant differences in MT/Sag curve correction between the two groups. Revision surgery patients had no difference in postop %pred PFTs; however there were significantly more patients with a clinically significant decline in PFTs [23 (35%) v 22 (22%), p50.03]. CONCLUSIONS: We performed the largest study to date evaluating pulmonary function tests (PFTs) on 164 adult deformity patients finding a significant decline in all measures of pulmonary function at two years following surgical correction. Surprisingly, there was a significant postoperative improvement in patients who had preoperative PFT impairment. Also, revision surgery more frequently results in a clinically significant decline in PFTs. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2013.07.396
P123. Comparison of Pulmonary Function in Adults Younger and Older than Age 60 Undergoing Spinal Deformity Surgery Ronald A. Lehman, Jr., MD1, Daniel G. Kang, MD2, Lawrence G. Lenke, MD3, Brenda A. Sides4; 1Potomac, MD, US; 2Bethesda, MD, US; 3 Washington University Medical Center Department of Orthopedic Surgery, St. Louis, MO, US; 4Washington University School of Medicine, St. Louis, MO, US BACKGROUND CONTEXT: The effect of age on pulmonary function remains uncertain in patients undergoing adult spinal deformity surgery. PURPOSE: The objective of this study was to determine differences in pulmonary function in adult patients who are either younger (Y) or older (O) than age 60 following spinal deformity surgery. We hypothesize that older age may further exacerbate impairment of pulmonary function following spinal deformity surgery.
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 28th Annual Meeting / The Spine Journal 13 (2013) 1S–168S
157S
STUDY DESIGN/SETTING: Retrospective review of prospectively collected data. PATIENT SAMPLE: Adult spinal deformity patients. OUTCOME MEASURES: Pulmonary function tests. METHODS: 128 consecutive adult deformity patients with idiopathic scoliosis undergoing surgical treatment were evaluated at a single institution with minimum two year follow-up. Prospectively collected PFTs, clinical records and radiographs were analyzed. RESULTS: There were 102 patients in Y group (avg age 39.3614.1 yrs) and 26 in O group (avg age 63.762.7 yrs), with similar follow-up (Y52.9 v O52.6 yrs, p50.27). There were no differences in average preop main thoracic (MT) curve magnitude (Y550.0deg, O554.8deg, p50.27); however O patients had significantly greater # of lumbar (5.9 v 4.2, p50.00), thoracic (9.1 v 7.3, p50.00), and total (15.0 v 11.5, p50.00) levels fused. We also found O patients had significantly lower absolute preop FEV1 (2.1 v 2.6L, p50.02) and FVC (2.7 v 3.3L, p50.05), but no differences in % pred PFTs. This relationship remained at two yrs, with lower absolute FEV1 (1.9 v 2.5L, p50.00) and FVC (2.5 v 3.1L, p50.00). A clinically significant decline in PFTs (greater than 10% pred FEV1) occurred in 8 (31%) O patients and 26 (25%) Y patients which was not statistically different (p50.63). We also observed preop PFT impairment (less than 65% pred FEV1) in 1 (4%) O patient, which significantly increased to 6 (23%, p50.02) O patients postoperatively, compared to Y group experiencing no change in the number of patients (n512, 12%) with PFT impairment postoperatively. CONCLUSIONS: This is the largest study to date evaluating age related reduction in PFTs. We found older patients have no significant difference in %predicted PFTs compared to younger patients postoperatively and no differences in the rate of clinically significant PFT decline ($10% pred FEV1). However, older patients more frequently (23% v 12%) experience PFT impairment (!65%pred FEV1) after spinal deformity surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
(T6-T8), using a repeated measures ANOVA with Sidak correction for multiple comparisons. RESULTS: After PSO and instrumentation with a thoracic pedicle screwrod construct, T4-T10 ROM was significantly reduced in all planes of motion from the intact condition (p!0.05). Augmentation of the longitudinal construct with either 1 or 2 TC did not significantly increase construct stability in flexion-extension and lateral bending compared to the augmented construct (pO0.05). In contrast, during axial rotation, T4-T10 ROM was reduced by 43% following addition of 2 TC (p!0.05), and was also reduced by 26% following 1 TC (pO0.05), but did not reach statistical significance. Focal segmental stability (T6-T8) at the PSO level had similar improvement in axial rotation stability following the addition of transverse connectors, with a 48% decrease in axial rotation after 2 TC (p!0.05), and addition of 1 TC decreased axial ROM by 29%, but again did not reach statistical significance (pO0.05). CONCLUSIONS: Two transverse connectors (cross links) improved torsional rigidity by 43%, with no differences in stability for all planes of motion over the use of one transverse connector. Therefore, in the setting of a PSO and long segment pedicle screw-rod construct, augmentation with at least two transverse connectors improves torsional rigidity. FDA DEVICE/DRUG STATUS: Thoracic pedicle screws (Approved for this indication).
http://dx.doi.org/10.1016/j.spinee.2013.07.397
PURPOSE: Long fusions (above L2) to the sacrum generate high stresses on the sacral screws that may lead to loosening or pseudarthrosis (Emami 2002, Weistroffer 2008). Surgical techniques to reduce strain on the sacral screws, by improving rigidity of the L5-S1 motion segment, include anterior column support, with anterior or transforaminal lumbar interbody fusion (ALIF or TLIF) and iliac fixation. The development of stand-alone anterior fixation (ALIF cages with imbedded screws L5 and S1 vertebral bodies) may serve to reduce the need for supplementary posterior pelvic fixation. We conducted a biomechanical study using a validated in-situ model to test our hypothesis that stand-alone anterior cages reduce strain on sacral screws comparably to bilateral iliac fixation. Outcome measures from testing included multi-axial compliance at the lumbo-sacral junction and strain on the S1 screws. METHODS: Seven lumbo-pelvic human cadavers (L1-full pelvis) were used for this study. Relative motion between L1-L5, L5-S1, and S1-pelvis were measured under a load-controlled pure moment up to 7.5 Nm in flexion/extension (F/E), axial rotation (AR), and lateral bending (LB). S1 pedicle screws were instrumented with strain gauges used to measuring pullout force during testing. Three different length posterior rods were fit to each specimen for progressive posterior fixation including bilateral L1-S1, bilateral L1-S1 with unilateral iliac screw, and bilateral L1-S1 with bilateral iliac screw. These constructs were tested with and without the presence of an ALIF cage at L5-S1. RESULTS: Bilateral L1-S1 posterior hardware alone and the addition of an ALIF cage reduced and F/E ROM from 6.7þ/-4.2 to 3.1þ/-1.3, in 3.3þ/-1.2 respectively which was not statistically significant. The progression of posterior fixation to uni- and bi-lateral iliac screws sequentially decreased F/E ROM to 1.2þ/-1.2 and 0.6þ/-0.6 , respectively. Observing the loads experienced on the SI screw, the addition of an ALIF cage did not reduce loading during extension motion. Progression of the fusion rods to a uni-iliac construct significantly increased extension loads on the S1 screws. The addition of an ALIF cage to bi-lateral iliac construct significantly decreased loads during flexion and insignificantly during extension
P124. Biomechanical Contribution of Transverse Connectors in the Setting of a Thoracic Pedicle Subtraction Osteotomy Ronald A. Lehman, Jr., MD1, Haines Paik, MD2, Daniel G. Kang, MD3, Robert W. Tracey, MD4, John P. Cody, MD5, Anton E. Dmitriev, PhD6; 1 Potomac, MD, US; 2Fairfax, VA, US; 3Bethesda, MD, US; 4Rockville, MD, US; 5Washington, DC, US; 6Clarksville, MD, US BACKGROUND CONTEXT: Little data is available to guide longitudinal construct planning after a pedicle subtraction osteotomy (PSO) in the thoracic spine. Previous investigations have suggested the role of transverse connectors (TC) in enhancing torsional rigidity following long segment thoracic pedicle screw-rod instrumentation. However, the biomechanical effect of augmentation with one or two TC after PSO in the thoracic spine has not been previously evaluated. PURPOSE: We investigated the biomechanical effect of augmenting a long thoracic pedicle screw-rod construct with transverse connectors after pedicle subtraction osteotomy. STUDY DESIGN/SETTING: Cadaveric biomechanical analysis. OUTCOME MEASURES: Range of motion. METHODS: Seven (7) fresh-frozen human cadaveric thoracic spines (T3T11) were prepared, maintaining all osteoligamentous structures, and intact range of motion testing was performed with non-destructive loading (66 Nm) in a six-degree-of-freedom spine simulator. The specimens were then instrumented from T4-T10 with bilateral 5.5-mm polyaxial titanium pedicle screws and 5.5-mm contoured rods, and then a PSO performed at T7. Range of motion was subsequently analyzed in the unaugmented construct, with 1 TC (T8-T9) and then 2 TC (T5-T6 and T9-T10). Range of motion (ROM) was analyzed in axial rotation, flexion-extension, and lateral bending loading planes over T4-T10 and at the PSO level
http://dx.doi.org/10.1016/j.spinee.2013.07.398
P125. Stand-Alone ALIF for Supplementation of Long Posterior Lumbosacral Fusion Constructs Jeremi M. Leasure, MS1, William Camisa, MS2, Sigurd H. Berven, MD3; 1 The Taylor Laboratories, San Francisco, CA, US; 2Taylor Collaboration, San Francisco, CA, US; 3University of California San Francisco, Department of Orthopaedic Surgery, San Francisco, CA, US
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.