- Email: [email protected]
P94. Multi-directional bending stiffness of the human lumbar intervertebral disc
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Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S
a minimum 2-year follow up. The preoperative diagnoses are degenerative stenosis, disc herniation, spondylolisthesis, degenerative lumbar scoliosis and degenerative disc disease. The indications are that patients present with more than 6 months of chronic low back pain, which have affected the quality of life and have not responded to adequate conservative treatment. Postoperatively lumbar fusion was radiographically assessed at 3, 6, 12, 18 and 24 month intervals, using AP, flexion-extension lateral, and oblique views. An independent physician conducted the data and X-ray review. Fusion parameters include: confluent bone mass bridging the fusion level; less than 12% anterior/posterior translation on flexion/extension x-rays; less than 5 degree rotation (Cobb angle) between flexion/extension x-rays; and maintenance of disc height. The degenerative changes of adjacent levels were also recorded. RESULTS: There were 17 males and 35 females. 25 (48%) patients aged over 70 years, with an average age of 70 years (range 61–82). Mean follow up time is 33 months (range 24–73). Most of the patients went through an uneventful hospital stay, only 2 patients had wound infections. There are 15 patients (29%) with 2 level fusion, 20 patients (38%) with 3 levels, 8 patients (15%) with 4 levels, 8 patients (15%) with 5 levels and 1 patient (2%) with 6 level fusion, with mean levels of 3.2. The most common attempted levels are L3-S1(34.6%). At final follow up, 3 patients (5.7%) developed pseudoarthrosis. Another 3 patients (5.7%) had indeterminate fusion, including one patient with vertebral compression fracture due to osteopenia. The remaining 46 patients obtained solid fusion (88%). At 2year follow up, 16 patients (31%) developed further degenerative changes at adjacent levels, including loss of disc height, scoliosis, retrolisthesis, kyphosis, and spontaneous fusion. Most (94%) of these changes occurred at the level above the fusion. Eventually, 3 patients underwent extended fusion. In addition, 2 patients developed severe osteoporosis. DISCUSSION: A recent study showed that elderly patients who have undergone lumbar decompression have satisfactory results similar to those for younger patients. However, there are a few reports specifically regarding the multilevel lumbar fusion rate in elderly patients. Our study showed 88% of patients aged 60 years or older achieved solid fusion, which is comparable with those of the younger group reported in literature. It was found that further disc degenerative changes occurred at adjacent levels, suggesting shifted stress to those levels. CONCLUSIONS: Elderly patients who have undergone multilevel lumbar decompression and fusion with instrumentation still can achieve a relatively good fusion rate. However, the achieved solid fusion can accelerate disc degeneration at the adjacent levels. Extending fusion may be needed. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00376-0
P89. The accuracy of pedicular screw placement: a comparative study between adult patients with scoliosis or traumatic lesions Marcelo Gruenberg1, Marcelo Valacco1, Carlos Sola´1, Matias Petracchi1, Eligio Ortolan1; 1Hospital Italiano Buenos Aires, Buenos Aires, Argentina HYPOTHESIS: For a safe screw insertion, most surgeons rely on the identification of anatomic landmarks during surgery, directly or under fluoroscopy or radiography. It is well known that certain conditions cause anatomic changes on spinal structures. The adult scoliotic spine is associated with alteration of the spatial location of the vertebras together with distortion caused by spondilosis. In contrast, young patients with traumatic lesions present a normal anatomy over the non-fractured vertebras. The purpose of this study was to compare the effectiveness of a conventional pedicle screw insertion technique in patients either with normal anatomy or with severe anatomic distortion. METHODS: Group A (traumatic) included 32 patients, 22 men and 10 women, with an average age of 36 years instrumented with 199 screws. Group B (scoliosis) included 42 patients, 34 women and 8 men, with an average age of 53 years, instrumented with 346 screws. All screws were
placed under strict supervision by one of two fellowship-trained surgeons who had been dedicated exclusively to the treatment of spinal pathology for more than ten years. Preoperatively, all patients in group A were evaluated by means of radiographs, CT scans and MRI. Patients in group B were all studied by radiographs and MRI; CT scans or radiculography were performed in selected cases on this group. The post-operative image evaluation was carried out by 2 fellows in training who did not participate in the management of the patients. The position of the screw was considered incorrect when its margins appeared outside the pedicle, beyond the anterior cortex or when a perforation of the pedicle cortex by more than 2 mm was visualized on CT scans. Every patient in both groups was studied by postoperative radiographs (A-P, lateral and oblique views). CT scans with images going through each of the instrumented pedicles were obtained from all patients of group A and from 8 patients from group B with radiological or clinical suspicion of screw malposition. RESULTS: One hundred and ninety-nine screws were placed in group A (thoracic spine, 66; lumbar spine, 131; sacrum, 2). Three hundred amd forty-eight screws were placed in group B (thoracic spine, 38; lumbar spine, 275; sacrum, 33). In group A, 4 out of 199 screws (2%) were found to be malpositioned. In group B, 6 screws out of 346 were malpositioned (1.7%). Neurological complications were only reported in 2 patients in group B. No vascular complications were reported in neither of the groups. DISCUSSION: Many techniques have been described for an accurate insertion of pedicle screws, most of them relying on the identification of the anatomic landmarks. Opposite with what we expected, we did not find significant differences between the rate of malpositioned screws in both groups (group A, 2% vs. group B, 1,7%). Among the factors that could have favorably influenced group B, we found that large approaches benefit a three-dimensional orientation and facilitate placing the screws in the desired position. Also, the multisegmentary fixation allows skipping one pedicle when its position results difficult to determine, and finally, in laminectomiced patients the direct pedicle palpation facilitates the screw orientation. CONCLUSIONS: Pedicle screws placed by experienced surgeons give rise to a low malpositioned rate with few neurological complications, even in patients presenting multiplanar deformities with degenerative changes. DISCLOSURES: Device or drug: pedicular screws. Status: approved. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00377-2
P94. Multi-directional bending stiffness of the human lumbar intervertebral disc David Spenciner, BS, PE1, David Greene, MD2, James Paiva, BA1, Mark Palumbo, MD2, Joseph Crisco, PhDb; 1RIH Orthopaedic Foundation, Inc., Providence, RI, USA; 2Brown Medical School, Providence, RI, USA HYPOTHESIS: A detailed understanding of the multi-directional biomechanical properties of the human intervertebral disc is critical for the successful design of artificial intervertebral discs (AIDs). The three principal anatomical axes (axial rotation, lateral bending, and flexion/extension) have provided researchers with the fundamental basis for studying the mechanics of the spine. However, physiological spine motion is complex and consists mainly of rotations that are combinations of the three principal rotations. It is unclear if the values in the literature can be extrapolated to these complex motions. Our objective was to develop an unconstrained apparatus for testing the multi-directional mechanical properties of spinal segments, specifically the 13 loading axes including these three anatomical principal axes, six axes that represent combinations of each pair of principal axes, and four axes that represent combinations of all three principal axes. This apparatus was then used to test the hypothesis that the stiffness of the human intervertebral disc does not differ with the direction of the loading axis. METHODS: A multi-directional, unconstrained apparatus was constructed to interface with a standard servohydraulic load frame. A total of seven human spinal specimens (L2/3 and L4/5) were obtained from cadavers
Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S (mean age 63.3⫾3.0 years). Anterior column units (ACUs) were prepared by removing the posterior elements from functional spinal units (FSUs), potting, and then mounting in the apparatus. Testing involved applying pure moments (⫾8 Nm at 0.1 Hz) to the ACUs about the 13 specified axes of rotation. The torque and rotation about the loading axis were recorded as well as the load and torque about the other orthogonal axes. Specimens were preconditioned with four cycles, and the data from the 5th cycle were recorded. Bending stiffness, as defined by the slope of the linear leastsquares fit of the torque vs. rotation curve, was calculated. The bending stiffness values across all directions were compared using a repeated measures ANOVA with Tukey post-hoc test. RESULTS: In general, the bending stiffness values of the ACUs demonstrated a significant dependence on the direction of loading. There was a statistically significant difference in the mean stiffness between flexion (FL) and left lateral bending (LLB) (p⬍0.001), FL and right lateral bending (RLB) (p⬍0.001), FL and right axial rotation (RAR) (p⬍0.001), and FL and left axial rotation (LAR) (p⫽0.001). Likewise, there was a statistically significant difference in the mean stiffness between extension (EX) and LLB (p⫽0.035) and EX and RLB (p⬍0.001). Lateral bending and axial rotation were not statistically different from each other. Along axes in the sagittal plane, there was not a statistically significant difference between the mean stiffnesses, except RLB and the combination of LLB and LAR (p⫽0.07). Along axes in the coronal plane, there were statistically significant differences, but the stiffness values of the intermediate axes were between the stiffness values of the bounding principal axes. DISCUSSION: An apparatus was designed to determine the multi-directional bending stiffness of the ACU. Only single levels of lumbar discs (ACUs) were studied and it is unknown whether FSUs would provide similar results. CONCLUSIONS: The results of this study provide novel data on the multi-directional bending stiffness of the intervertebral disc that can not be extrapolated from stiffness values in the literature. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00378-4
P99. Quality of life following percutaneous vertebroplasty Tom Faciszewski, MD1, Fergus McKiernan, MD1; 1Marshfield Clinic, Marshfield, WI, USA HYPOTHESIS: Percutaneous vertebroplasty (PV) relieves pain in patients with symptomatic osteoporotic vertebral compression fractures (VCFs) that have failed non-operative treatment. Few studies have reported the functional outcome of such patients. To date, no prospective study has reported the long-term symptomatic and functional outcome of such patients using an instrument validated for use in an osteoporotic population. Herein we report the quality of life following PV using a visual analog scale (VAS) and a disease-specific health related quality of life (HRQL) outcome instrument. METHODS: This is an IRB approved, prospective study of consecutive patients who underwent PV to treat painful osteoporotic VCFs. All subjects provided informed consent. Patients with pathologic fractures due to malignancy and multiple myeloma were excluded. At enrollment and 1 year postoperatively subjects completed the Osteoporosis Quality of Life Questionnaire (OQLQ), a validated, 30-item, 5-domain, disease-specific instrument that measures HRQL in osteoporotic women with back pain due to VCF. Two weeks, 2 months and 6 months postoperatively subjects completed the Mini-Osteoporosis Quality of Life Questionnaire (mini-OQLQ) a 10-item, 5-domain, validated extraction of OQLQ. Two gender-neutral questions were added to address the 2 mini-OQLQ questions that were gender-specific. Pain was rated (VAS: 1-10) 1 day postop and at each other evaluation point. Six month results are reported. RESULTS: Forty-two Caucasian subjects (29 women,13 men) underwent 45 PV procedures to treat 62 VCFs. Average age was 74.5 years, 31.5 years past menopause. 52.4% were ever- and 26.2% current-glucocorticoid users. 69% were ever- and 21.4% current-smokers with an average 56.3
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pack-year consumption. Average bone mineral density T- and Z-scores were ⫺1.98/⫺0.78 (lumbar spine) and ⫺2.26/⫺0.84 (femoral neck) respectively. 59.1% had sustained prior fragility fracture. 61.9% subjects were on active anti-osteoporosis treatment at presentation. One day following PV VAS pain rating fell from 7.8 to 2.9 (p⬍0.001). Mean VAS pain rating increased ⫹0.9 from postoperative day 1 to month 6 (NS, p⫽0.26). Four of five HRQL domains (symptoms, physical function, activities of daily living, leisure) and the gender neutral equivalent questions improved significantly at postoperative week 2 (p⬍0.001). The fifth HRQL domain (emotional function) also improved (p⫽0.058). None of the HRQL changed significantly from 2 weeks to 6 months. There were 6 cement leaks (5 into the adjacent disc, each anticipated by preoperative imaging) and none were symptomatic. No serious adverse events were ascribed to PV. Subsequent vertebral fracture rate was not greater than expected. DISCUSSION: This is the first prospective, long-term outcome analysis of HRQL using a validated disease-specific instrument in osteoporotic subjects following PV. Contrary to the natural history of VCF, fracture pain is quickly improved following PV and is associated with continuous functional improvement through 6 months. Adverse events are infrequent and rarely serious when performed by skilled operators. Concern that PV may accelerate subsequent vertebral fracture rate was not confirmed in this study. CONCLUSIONS: Quality of life improves immediately following percutaneous vertebroplasty and remains improved through 6 months. DISCLOSURES: Device or drug: PMMA and barium. Status: not approved. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00379-6
P104. A prospective study of the validity of the visual analogue scale for prediction of surgical outcome Paula Trief, PhD1, Robert Ploutz-Snyder, PhD1, Bruce Fredrickson, MD1; 1State University of New York Upstate Medical University, Syracuse, NY, USA HYPOTHESIS: The 0 (no pain) to100 (pain as bad as it could be) point Visual Analogue Scale (VAS) is widely used to assess pain outcomes, yet it’s validity is still uncertain. Pre-operative VAS has been shown to discriminate between diagnostic groups and show a moderate correlation with post-surgical analgesic intake and patient satisfaction. However, whether changes in pain mirrors changes in function has not been explored. The hypothesis was that, for patients who underwent anterior lumbar fusion surgery, the change in pain would predict change in function from pre- to post-surgery. METHODS: Subjects (N⫽168) enrolled in a multi-site trial of 2 fusion systems (InFix vs. BAK) completed measures of pain (Visual Analogue Scale) and function (SF36-Physical Composite Score, SF36-Physical Function subscale, modified-Oswestry Disability questionnaire) prior to, and 12 and 24 months post, fusion surgery. Blocked multiple regression analyses were used to predict functional outcomes 12 and 24 months post surgery, first by entering the relevant pre-op function predictor, then by adding a pain-change predictor. This approach allowed us to establish the significance of adding the pain-change predictor to the prediction model. In all cases, the addition of the pain-change predictor significantly improved the model, and thus the full models are interpreted with an emphasis on the independent predictive value (semi-partial correlations) of the pain-change predictor relative to pre-operative function. RESULTS: Pre-to-post surgical pain decrease was a significant predictor of functional improvements at 12 months, indicated both by a significant increase in the R-square value (p⬍.001) of the second block regression over the first, as well as by significant beta weight in the full model (β⫽⫺.71, p⬍.001). Furthermore, the squared semi-partial correlation coefficient revealed that pain-change alone predicts 51% of the variance in 12 month function; far superior to the pre-operative function predictor alone (18%). These results were mirrored in predicting 24m function, with a
Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S
a minimum 2-year follow up. The preoperative diagnoses are degenerative stenosis, disc herniation, spondylolisthesis, degenerative lumbar scoliosis and degenerative disc disease. The indications are that patients present with more than 6 months of chronic low back pain, which have affected the quality of life and have not responded to adequate conservative treatment. Postoperatively lumbar fusion was radiographically assessed at 3, 6, 12, 18 and 24 month intervals, using AP, flexion-extension lateral, and oblique views. An independent physician conducted the data and X-ray review. Fusion parameters include: confluent bone mass bridging the fusion level; less than 12% anterior/posterior translation on flexion/extension x-rays; less than 5 degree rotation (Cobb angle) between flexion/extension x-rays; and maintenance of disc height. The degenerative changes of adjacent levels were also recorded. RESULTS: There were 17 males and 35 females. 25 (48%) patients aged over 70 years, with an average age of 70 years (range 61–82). Mean follow up time is 33 months (range 24–73). Most of the patients went through an uneventful hospital stay, only 2 patients had wound infections. There are 15 patients (29%) with 2 level fusion, 20 patients (38%) with 3 levels, 8 patients (15%) with 4 levels, 8 patients (15%) with 5 levels and 1 patient (2%) with 6 level fusion, with mean levels of 3.2. The most common attempted levels are L3-S1(34.6%). At final follow up, 3 patients (5.7%) developed pseudoarthrosis. Another 3 patients (5.7%) had indeterminate fusion, including one patient with vertebral compression fracture due to osteopenia. The remaining 46 patients obtained solid fusion (88%). At 2year follow up, 16 patients (31%) developed further degenerative changes at adjacent levels, including loss of disc height, scoliosis, retrolisthesis, kyphosis, and spontaneous fusion. Most (94%) of these changes occurred at the level above the fusion. Eventually, 3 patients underwent extended fusion. In addition, 2 patients developed severe osteoporosis. DISCUSSION: A recent study showed that elderly patients who have undergone lumbar decompression have satisfactory results similar to those for younger patients. However, there are a few reports specifically regarding the multilevel lumbar fusion rate in elderly patients. Our study showed 88% of patients aged 60 years or older achieved solid fusion, which is comparable with those of the younger group reported in literature. It was found that further disc degenerative changes occurred at adjacent levels, suggesting shifted stress to those levels. CONCLUSIONS: Elderly patients who have undergone multilevel lumbar decompression and fusion with instrumentation still can achieve a relatively good fusion rate. However, the achieved solid fusion can accelerate disc degeneration at the adjacent levels. Extending fusion may be needed. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00376-0
P89. The accuracy of pedicular screw placement: a comparative study between adult patients with scoliosis or traumatic lesions Marcelo Gruenberg1, Marcelo Valacco1, Carlos Sola´1, Matias Petracchi1, Eligio Ortolan1; 1Hospital Italiano Buenos Aires, Buenos Aires, Argentina HYPOTHESIS: For a safe screw insertion, most surgeons rely on the identification of anatomic landmarks during surgery, directly or under fluoroscopy or radiography. It is well known that certain conditions cause anatomic changes on spinal structures. The adult scoliotic spine is associated with alteration of the spatial location of the vertebras together with distortion caused by spondilosis. In contrast, young patients with traumatic lesions present a normal anatomy over the non-fractured vertebras. The purpose of this study was to compare the effectiveness of a conventional pedicle screw insertion technique in patients either with normal anatomy or with severe anatomic distortion. METHODS: Group A (traumatic) included 32 patients, 22 men and 10 women, with an average age of 36 years instrumented with 199 screws. Group B (scoliosis) included 42 patients, 34 women and 8 men, with an average age of 53 years, instrumented with 346 screws. All screws were
placed under strict supervision by one of two fellowship-trained surgeons who had been dedicated exclusively to the treatment of spinal pathology for more than ten years. Preoperatively, all patients in group A were evaluated by means of radiographs, CT scans and MRI. Patients in group B were all studied by radiographs and MRI; CT scans or radiculography were performed in selected cases on this group. The post-operative image evaluation was carried out by 2 fellows in training who did not participate in the management of the patients. The position of the screw was considered incorrect when its margins appeared outside the pedicle, beyond the anterior cortex or when a perforation of the pedicle cortex by more than 2 mm was visualized on CT scans. Every patient in both groups was studied by postoperative radiographs (A-P, lateral and oblique views). CT scans with images going through each of the instrumented pedicles were obtained from all patients of group A and from 8 patients from group B with radiological or clinical suspicion of screw malposition. RESULTS: One hundred and ninety-nine screws were placed in group A (thoracic spine, 66; lumbar spine, 131; sacrum, 2). Three hundred amd forty-eight screws were placed in group B (thoracic spine, 38; lumbar spine, 275; sacrum, 33). In group A, 4 out of 199 screws (2%) were found to be malpositioned. In group B, 6 screws out of 346 were malpositioned (1.7%). Neurological complications were only reported in 2 patients in group B. No vascular complications were reported in neither of the groups. DISCUSSION: Many techniques have been described for an accurate insertion of pedicle screws, most of them relying on the identification of the anatomic landmarks. Opposite with what we expected, we did not find significant differences between the rate of malpositioned screws in both groups (group A, 2% vs. group B, 1,7%). Among the factors that could have favorably influenced group B, we found that large approaches benefit a three-dimensional orientation and facilitate placing the screws in the desired position. Also, the multisegmentary fixation allows skipping one pedicle when its position results difficult to determine, and finally, in laminectomiced patients the direct pedicle palpation facilitates the screw orientation. CONCLUSIONS: Pedicle screws placed by experienced surgeons give rise to a low malpositioned rate with few neurological complications, even in patients presenting multiplanar deformities with degenerative changes. DISCLOSURES: Device or drug: pedicular screws. Status: approved. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00377-2
P94. Multi-directional bending stiffness of the human lumbar intervertebral disc David Spenciner, BS, PE1, David Greene, MD2, James Paiva, BA1, Mark Palumbo, MD2, Joseph Crisco, PhDb; 1RIH Orthopaedic Foundation, Inc., Providence, RI, USA; 2Brown Medical School, Providence, RI, USA HYPOTHESIS: A detailed understanding of the multi-directional biomechanical properties of the human intervertebral disc is critical for the successful design of artificial intervertebral discs (AIDs). The three principal anatomical axes (axial rotation, lateral bending, and flexion/extension) have provided researchers with the fundamental basis for studying the mechanics of the spine. However, physiological spine motion is complex and consists mainly of rotations that are combinations of the three principal rotations. It is unclear if the values in the literature can be extrapolated to these complex motions. Our objective was to develop an unconstrained apparatus for testing the multi-directional mechanical properties of spinal segments, specifically the 13 loading axes including these three anatomical principal axes, six axes that represent combinations of each pair of principal axes, and four axes that represent combinations of all three principal axes. This apparatus was then used to test the hypothesis that the stiffness of the human intervertebral disc does not differ with the direction of the loading axis. METHODS: A multi-directional, unconstrained apparatus was constructed to interface with a standard servohydraulic load frame. A total of seven human spinal specimens (L2/3 and L4/5) were obtained from cadavers
Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S (mean age 63.3⫾3.0 years). Anterior column units (ACUs) were prepared by removing the posterior elements from functional spinal units (FSUs), potting, and then mounting in the apparatus. Testing involved applying pure moments (⫾8 Nm at 0.1 Hz) to the ACUs about the 13 specified axes of rotation. The torque and rotation about the loading axis were recorded as well as the load and torque about the other orthogonal axes. Specimens were preconditioned with four cycles, and the data from the 5th cycle were recorded. Bending stiffness, as defined by the slope of the linear leastsquares fit of the torque vs. rotation curve, was calculated. The bending stiffness values across all directions were compared using a repeated measures ANOVA with Tukey post-hoc test. RESULTS: In general, the bending stiffness values of the ACUs demonstrated a significant dependence on the direction of loading. There was a statistically significant difference in the mean stiffness between flexion (FL) and left lateral bending (LLB) (p⬍0.001), FL and right lateral bending (RLB) (p⬍0.001), FL and right axial rotation (RAR) (p⬍0.001), and FL and left axial rotation (LAR) (p⫽0.001). Likewise, there was a statistically significant difference in the mean stiffness between extension (EX) and LLB (p⫽0.035) and EX and RLB (p⬍0.001). Lateral bending and axial rotation were not statistically different from each other. Along axes in the sagittal plane, there was not a statistically significant difference between the mean stiffnesses, except RLB and the combination of LLB and LAR (p⫽0.07). Along axes in the coronal plane, there were statistically significant differences, but the stiffness values of the intermediate axes were between the stiffness values of the bounding principal axes. DISCUSSION: An apparatus was designed to determine the multi-directional bending stiffness of the ACU. Only single levels of lumbar discs (ACUs) were studied and it is unknown whether FSUs would provide similar results. CONCLUSIONS: The results of this study provide novel data on the multi-directional bending stiffness of the intervertebral disc that can not be extrapolated from stiffness values in the literature. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00378-4
P99. Quality of life following percutaneous vertebroplasty Tom Faciszewski, MD1, Fergus McKiernan, MD1; 1Marshfield Clinic, Marshfield, WI, USA HYPOTHESIS: Percutaneous vertebroplasty (PV) relieves pain in patients with symptomatic osteoporotic vertebral compression fractures (VCFs) that have failed non-operative treatment. Few studies have reported the functional outcome of such patients. To date, no prospective study has reported the long-term symptomatic and functional outcome of such patients using an instrument validated for use in an osteoporotic population. Herein we report the quality of life following PV using a visual analog scale (VAS) and a disease-specific health related quality of life (HRQL) outcome instrument. METHODS: This is an IRB approved, prospective study of consecutive patients who underwent PV to treat painful osteoporotic VCFs. All subjects provided informed consent. Patients with pathologic fractures due to malignancy and multiple myeloma were excluded. At enrollment and 1 year postoperatively subjects completed the Osteoporosis Quality of Life Questionnaire (OQLQ), a validated, 30-item, 5-domain, disease-specific instrument that measures HRQL in osteoporotic women with back pain due to VCF. Two weeks, 2 months and 6 months postoperatively subjects completed the Mini-Osteoporosis Quality of Life Questionnaire (mini-OQLQ) a 10-item, 5-domain, validated extraction of OQLQ. Two gender-neutral questions were added to address the 2 mini-OQLQ questions that were gender-specific. Pain was rated (VAS: 1-10) 1 day postop and at each other evaluation point. Six month results are reported. RESULTS: Forty-two Caucasian subjects (29 women,13 men) underwent 45 PV procedures to treat 62 VCFs. Average age was 74.5 years, 31.5 years past menopause. 52.4% were ever- and 26.2% current-glucocorticoid users. 69% were ever- and 21.4% current-smokers with an average 56.3
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pack-year consumption. Average bone mineral density T- and Z-scores were ⫺1.98/⫺0.78 (lumbar spine) and ⫺2.26/⫺0.84 (femoral neck) respectively. 59.1% had sustained prior fragility fracture. 61.9% subjects were on active anti-osteoporosis treatment at presentation. One day following PV VAS pain rating fell from 7.8 to 2.9 (p⬍0.001). Mean VAS pain rating increased ⫹0.9 from postoperative day 1 to month 6 (NS, p⫽0.26). Four of five HRQL domains (symptoms, physical function, activities of daily living, leisure) and the gender neutral equivalent questions improved significantly at postoperative week 2 (p⬍0.001). The fifth HRQL domain (emotional function) also improved (p⫽0.058). None of the HRQL changed significantly from 2 weeks to 6 months. There were 6 cement leaks (5 into the adjacent disc, each anticipated by preoperative imaging) and none were symptomatic. No serious adverse events were ascribed to PV. Subsequent vertebral fracture rate was not greater than expected. DISCUSSION: This is the first prospective, long-term outcome analysis of HRQL using a validated disease-specific instrument in osteoporotic subjects following PV. Contrary to the natural history of VCF, fracture pain is quickly improved following PV and is associated with continuous functional improvement through 6 months. Adverse events are infrequent and rarely serious when performed by skilled operators. Concern that PV may accelerate subsequent vertebral fracture rate was not confirmed in this study. CONCLUSIONS: Quality of life improves immediately following percutaneous vertebroplasty and remains improved through 6 months. DISCLOSURES: Device or drug: PMMA and barium. Status: not approved. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00379-6
P104. A prospective study of the validity of the visual analogue scale for prediction of surgical outcome Paula Trief, PhD1, Robert Ploutz-Snyder, PhD1, Bruce Fredrickson, MD1; 1State University of New York Upstate Medical University, Syracuse, NY, USA HYPOTHESIS: The 0 (no pain) to100 (pain as bad as it could be) point Visual Analogue Scale (VAS) is widely used to assess pain outcomes, yet it’s validity is still uncertain. Pre-operative VAS has been shown to discriminate between diagnostic groups and show a moderate correlation with post-surgical analgesic intake and patient satisfaction. However, whether changes in pain mirrors changes in function has not been explored. The hypothesis was that, for patients who underwent anterior lumbar fusion surgery, the change in pain would predict change in function from pre- to post-surgery. METHODS: Subjects (N⫽168) enrolled in a multi-site trial of 2 fusion systems (InFix vs. BAK) completed measures of pain (Visual Analogue Scale) and function (SF36-Physical Composite Score, SF36-Physical Function subscale, modified-Oswestry Disability questionnaire) prior to, and 12 and 24 months post, fusion surgery. Blocked multiple regression analyses were used to predict functional outcomes 12 and 24 months post surgery, first by entering the relevant pre-op function predictor, then by adding a pain-change predictor. This approach allowed us to establish the significance of adding the pain-change predictor to the prediction model. In all cases, the addition of the pain-change predictor significantly improved the model, and thus the full models are interpreted with an emphasis on the independent predictive value (semi-partial correlations) of the pain-change predictor relative to pre-operative function. RESULTS: Pre-to-post surgical pain decrease was a significant predictor of functional improvements at 12 months, indicated both by a significant increase in the R-square value (p⬍.001) of the second block regression over the first, as well as by significant beta weight in the full model (β⫽⫺.71, p⬍.001). Furthermore, the squared semi-partial correlation coefficient revealed that pain-change alone predicts 51% of the variance in 12 month function; far superior to the pre-operative function predictor alone (18%). These results were mirrored in predicting 24m function, with a