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P47. Outcomes of Pedicle Subtraction Osteotomies for Fixed Sagittal Imbalance
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Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S
P45. Does Body Mass Index (BMI) Affect the Clinical Outcome of 1-level ProDisc-LÒ IDE Patients? Jeffrey A. Goldstein, MD1; 1NYU Hospital for Joint Diseases, New York, NY, USA BACKGROUND CONTEXT: Prevelance of population towards being classified as overweight or obese is on the rise. In the current climate of healthcare, BMI value is viewed as an important reflection on the health status of a patient and the degree of risk associated with surgery. Often patients with severe back pain limit their recreational activity leading to possible weight gain. There is very little information in the literature as to whether pre-operatively BMI effects clinical outcome after spine surgery. PURPOSE: This purpose of this analysis was to examine Class I clinical results from the ProDisc-L IDE trial to determine if pre-operative BMI was a indicator of clinical success either in the total disc replacement (TDR) or circumferential fusion treatment arms. STUDY DESIGN/SETTING: A randomized, multi-center prospective clinical study was completed to assess the safety and efficacy of the ProDisc-L total disc replacement (TDR) prosthesis (Synthes Spine, L.P., West Chester, PA) compared to circumferential fusion (Fusion) at one level between L3-S1. PATIENT SAMPLE: A total of 236 patients were treated in the trial, 161 patients with ProDisc-L and 75 patients with Fusion. OUTCOME MEASURES: Assessment included Oswestry Disability Index (ODI), SF-36, Visual Analog Scale (VAS) Pain, and VAS Satisfaction. METHODS: In the ProDisc-L IDE trial patients with a BMI greater than 40 were excluded from the study. The 161 patients that received the device were divided into 4 groups based on BMI: less than or equal to 20; between 20 and 29 (20 to 29); 29 to 35; and greater than or equal to 35. Pre-operative and post-operative assessment was performed at 6 weeks, 3, 6, 12, 18, and 24 months. RESULTS: Demographics were similar between each of the four subgroups. The largest percentage of women and men were in the BMI 20 to 29 group (70% women, 60% men). Operative level, smoking status, age and length of hospital stay were all similar between the four groups. Significant differences were seen between the groups when examining blood loss and operative time. The decrease in ODI score was not statistically different between the four BMI groups [ (less than 20) 24.0618.42; (20 to 29) 29.9623.32; (29 to 35) 25.4622.4; (greater than 35) 37.0627.54; p50.5840 ]. Similarly, the change in VAS Pain scores [ (less than 20) 25.6629.47; (20 to 29) 43.4631.62; (29 to 35) 29.8630.73; (greater than 35) 50.6631.44 ] and VAS Satisfaction scores [(less than 20) 75.43622.77; (20 to 29) 78.60627.99; (29 to 35) 71.09632.32; (greater than 35) 71.11640.49] were not found to be significant (p50.0709, p50.5860 respectively). Assessment of VAS Improvement also indicated a non-significant difference (p50.7681) between the four BMI groups. CONCLUSIONS: At 2 years follow-up it appears BMI does not have an effect on the clinical results and overall success of a patient following lumbar TDR or circumferential fusion. FDA DEVICE/DRUG STATUS: ProDisc-L: Approved for this indication.
workers’ compensation status. In a focus on objective outcomes relevant to a workers’ compensations setting, a recent study has reported returnto-work (RTW) rates of 36% at an average of 2 years following fusion surgery. However, the combination of spinal fusion with postoperative rehabilitation in relation to treatment outcomes has rarely been studied. PURPOSE: To compare objective socioeconomic outcomes of treatment in chronic disabling occupational spinal disorders (CDOSD) for the combination of spinal fusion surgery plus functional restoration, compared with rehabilitation alone.To compare key outcomes with historic lumbar fusion with usual aftercare from a major state workers’ compensation setting. STUDY DESIGN/SETTING: A prospective cohort study of consecutive patients undergoing spinal fusion (F) procedures before functional restoration for CDOSD in an outpatient interdisciplinary rehabilitation setting, vs. all other CDOSD patients not having a fusion (NF) from the same cohort. PATIENT SAMPLE: A consecutive cohort of 3066 CDOSD patients admitted to a functional restoration program were studied prospectively. The F group (N5383) underwent spine fusion, while the remaining 2683 patients did not have a fusion, but may have had other types of spinal surgery. OUTCOME MEASURES: Relevant socioeconomic outcomes were collected via a structured one-year post-rehabilitation interview, including RTW; work retention; healthcare utilization; new surgeries; new injury claims; case settlement; and Social Security Disability Income (SSDI) status. METHODS: All patients were totally or partially disabled before admission to an intensive, medically-supervised, functional restoration program combining quantitatively-directed exercise progression with a multimodal disability management approach. RESULTS: Initial analyses demonstrated that the NF group had a statistically significant advantage in RTW (88% vs. 81%), work retention 1 year after treatment (82% vs. 74%), and was less likely to seek healthcare from a new provider (24% vs. 35%) or to have SSDI (3% vs. 10%). However, after adjusting statistically for demographic differences and comorbid depression, all significant outcome differences disappeared, and the two groups were statistically similar. Key outcome variables for the lumbar fusion cohort also stood in stark contrast to valid historic controls of lumbar fusion with usual care. The outcomes included RTW of 32–36% and reoperation rates of 23% for usual care after fusion, versus 79% RTW rates and 3% reoperation rates for the functional restoration group. CONCLUSIONS: These results indicate that spinal fusion surgical patients, if administered appropriate postoperative rehabilitation, demonstrate highly satisfactory outcomes that are comparable to patients who have not undergone fusions after work-related injuries. These outcomes are also superior compared to historic controls of fusion with usual postoperative care. The overall conclusion of this study is that poor fusion outcomes in CDOSD patients may be, at least partially, related to patient selection or to inadequate attention to postoperative rehabilitation strategies. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.237
doi: 10.1016/j.spinee.2007.07.236
P46. Excellent Objective Spine Fusion Outcomes if Combined with Optimum Functional Restoration in Occupational Spinal Disorders Brian Theodore, MS1, Tom Mayer, MD2, Robert Gatchel, PhD1; 1 University of Texas at Arlington, Arlington, TX, USA; 2Productive Rehabilitation Institute of Dallas for Ergonomics, Dallas, TX, USA BACKGROUND CONTEXT: Controversy exists over the relationship between spine fusion surgery and successful therapeutic outcomes. Systematic reviews over the last two decades report a variety of competing outcomes, thus making it difficult to compile evidence in a systematic and objective manner. Additionally, many studies do not take into account
P47. Outcomes of Pedicle Subtraction Osteotomies for Fixed Sagittal Imbalance Eric Buchl, MPAS, PA-C1, Alexis Shelokov, MD2, Jeff Ganer1, Richard Hostin, MD1; 1Consulting Orthopedists, Plano, TX, USA; 2Baylor Scoliosis Center, Plano, TX, USA BACKGROUND CONTEXT: In recent years there has been an aggressive trend to correct fixed sagittal plane imbalance with a single level pedicle subtraction osteotomie. Historical treatment consisted of either multiple Smith-Petersen osteotomies or anterior and posterior osteotomie. The present goal is to demonstrate the effectiveness of pedicle subtraction osteotomie to correct fixed sagittal plane imbalance.
Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S PURPOSE: The purpose of this study is to analyses clinical, radiographic, and complications of pedicle subtraction osteotomies (PSO). STUDY DESIGN/SETTING: Chart and radiographic review of a single surgeon’s patient, sequential cohort was carried out to identify: radiogafic outcomes, complications, and clincin outcomes. PATIENT SAMPLE: Patients who underwent PSO for sagittal imbalance greater then 10 cm were included in the cohort. OUTCOME MEASURES: (1) Identified radiographic outcomes (2) Surgical Complications (3) Pseudarthrosis rate (4) SRS-22 (4) Oswestry questioner. METHODS: A single surgeon consecutive patient cohort of fixed sagittal imbalance (C7-S1O10 cm) was analyzed for demographic data, anesthetic risk factors, peri-operative data, and complications. Radiograph analyses included pre-operatively, post-operatively and last follow up. Clinical outcomes included Oswestry questionnaire and the SRS questionnaire. RESULTS: Eighteen patients, 15 female and 3 males with an average age of 56.0 (range, 19.8–73.4y) with fixed sagittal imbalance were treated with PSOs by a single surgeon with minimal one year follow up, average 2.4 years (range, 1.0–4.1y) were included in the study. Average operative time for all procedures was 5.7 hours (range, 2.6–10.9h) with an average estimated blood loss of 2902cc (range, 440–9000cc). At most recent follow up overall sagittal vertical axes improved 76.6% from 13.9cm (range, 10.3 to 19.0cm) to 3.3cm (range, 3.7 to 11.8cm); with an average lumbar lordosis improvement from 29 degrees (range, 2 to 61d) to 46 degrees (range, 16-82d). Early complications included 7 dural tears, 1 stenosis requiring surgical decompression, 1 epidural hematoma requiring surgical decompression, 1 nerve root injury with full recovery by 3 months, 1 adjacent segment fracture, and 1 acute hardware failure. Late complications included 2 Pseudarthrosis, 1 hip flexor contractor related to Parkinsonism Associated Spinal Deformity (PASD), 0 wound infections, 0 permanent neurologic deficits. SRS questionnaire at most recent follow up were: overall 3.21, Self image/appearance 3.04, satisfaction 3.88, pain 3.04, function/ activity 2.94, and mental health 3.38. CONCLUSIONS: As previous described in the literature PSO is an effective means to correct fixed sagittal imbalance and achieve a large amount of correction at a single level. Our cohort is consistent with previous studies; patients maintained good correction at minimum of one year follow up and good clinical results. Based on this cohort PSO remains a superior tool to correct fixed sagittal imbalance. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.238
P48. The Effect of Body Mass Index on Lumbar Lordosis on the Jackson (OSI) Frame Justin Bundy1, Norman Chutkan, MD2, Hiatao Zhou2; 1Medical College of Georgia, Augusta, GA, USA; 2GA, USA BACKGROUND CONTEXT: Studies have investigated patient positioning, various operative frames and there effect on sagittal alignment. However, there is a paucity of information regarding patient selection and body habitus as it relates to intra-operative alignment. PURPOSE: A prospective evaluation to determine if body mass index (BMI) influences the degree of intra-operative lumbar lordosis in patients undergoing operative treatment on the Orthopedic Systems Incorporated (OSI; Jackson) frame. STUDY DESIGN/SETTING: From July 2006 to December 2006, 25 consecutive patients undergoing posterior spinal instrumentation and fusion on the OSI frame at one hospital under the supervision of the senior author were included. PATIENT SAMPLE: 25 consecutive patients were included all undergoing posterior spinal instrumentation and fusion.
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METHODS: Patients were radiographed pre-op standing. Radiographs were taken with arms over head and in a relaxed standing position. They were positioned in a standard manner by the same attending surgeon and lateral radiographs obtained prior to surgical prepping.Chest, iliac, and thigh pads were positioned and knees were placed in 15 degrees of flexion with feet over a pillow. Arms were placed to sides with elbows flexed and shoulders externally rotated. Intervertebral body angle measurements were obtained from L1-S1 using the method of Cobb simultaneously by two treating surgeons. All patients were weighed on a single scale and height measured. Changes in angle measurements were compared to BMI and statistical analysis applied. RESULTS: Mean standing lordosis of 51.6 with a range of 20–75 degrees. Mean prone lordosis of 60.7 with a range of 34-80 on the Jackson frame. Mean BMI of 32.9 with a range of 21–49. Mean change in degrees 9.1 with a range of 0–17 degrees. No differences between sexes (pO0.05) ANOVA was used to determine if BMI infuenced lordosis on the Jackson frame and an F value of 9.53709 with a p!0.00802 was found. Using linear regression a multiple regression correlation coefficient of 0.63655 was found. CONCLUSIONS: The current study is the first in which patient selection and use of the OSI frame has been evaluated. These data suggest that BMI influences lumbar lordosis on the OSI frame and that care must be used when dealing with a population with large BMI on the OSI frame FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.239
P49. Monitoring for Ischemic Optic Neuropathy During Prone Spine Surgery? Pupillometry and Retinal Imaging Henry Bennett, PhD1, Geordie Grant, MD1, Ming Xiong, MD1, Roger Turbin, MD1, Leslie Osei-Tutu, MD1, Robert Heary, MD1; 1 UMDNJ, Newark, NJ, USA BACKGROUND CONTEXT: Postoperative visual loss (POVL) is a rare but devastating and poorly understood complication usually affecting longer prone spine surgery patients. The primary presentation is posterior optic neuropathy with bilateral visual loss which does not resolve. In a review of 93 spine cases, longer surgeries with higher blood loss and fluid replacement were partially descriptive of POVL while blood pressure was not (1). PURPOSE: The purpose was to examine changes to the eyes and optic nerve function during prone spine surgery of four hours duration or greater. STUDY DESIGN/SETTING: This is an ongoing prospective, randomized control study of optic and visual system changes across two Jackson table positions- flat or slightly head elevated.The present report is of the feasibility of light flash evoked pupillometry (LVEP) during high-dose remifentanil infusion which produces a profound miosis. PATIENT SAMPLE: The study is designed for 32 patients, 16 each in one of two table positions, who are undergoing prone lumbar spine surgery scheduled for at least four hours. OUTCOME MEASURES: 1. Intraoperative changes over time of intraocular pressure (IOP), results of retinal digital photography (RDP), and changes in latency and amplitude to LFEP. METHODS: A modified Dupaco ‘‘Proneview’’ helmet system frame affords access to the eyes from beneath the Jackson table in the prone position (2). Hourly measurements included IOP (Medtronic TonoPen XL) with contact lens, dilated (tropicamide 1%), RDP (Nidex NM200), and LFEP (NeurOptics). RESULTS: Two patients required L3-S1 amd T11-S1 re-instrumentation and underwent induction with midazolam, fentanyl, lidocaine and propofol followed by cisastracurium. Maintenance anesthesia consisted of remifentanil (0.05–0.16 mcg/kg/min) and cisastracurium (1.5 mcg/kg/min) infusions with isoflurane (0.5-0.8% ET). The patients required 5.1–6.5L crystalloid and 500 ml albumin with EBL of 1.6–1.8L and 400–750 ml cell saver return over the 6–6:30 hr durations of surgery. LFEP latencies and amplitudes remained stable throughout (Figs. 1–2).
Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S
P45. Does Body Mass Index (BMI) Affect the Clinical Outcome of 1-level ProDisc-LÒ IDE Patients? Jeffrey A. Goldstein, MD1; 1NYU Hospital for Joint Diseases, New York, NY, USA BACKGROUND CONTEXT: Prevelance of population towards being classified as overweight or obese is on the rise. In the current climate of healthcare, BMI value is viewed as an important reflection on the health status of a patient and the degree of risk associated with surgery. Often patients with severe back pain limit their recreational activity leading to possible weight gain. There is very little information in the literature as to whether pre-operatively BMI effects clinical outcome after spine surgery. PURPOSE: This purpose of this analysis was to examine Class I clinical results from the ProDisc-L IDE trial to determine if pre-operative BMI was a indicator of clinical success either in the total disc replacement (TDR) or circumferential fusion treatment arms. STUDY DESIGN/SETTING: A randomized, multi-center prospective clinical study was completed to assess the safety and efficacy of the ProDisc-L total disc replacement (TDR) prosthesis (Synthes Spine, L.P., West Chester, PA) compared to circumferential fusion (Fusion) at one level between L3-S1. PATIENT SAMPLE: A total of 236 patients were treated in the trial, 161 patients with ProDisc-L and 75 patients with Fusion. OUTCOME MEASURES: Assessment included Oswestry Disability Index (ODI), SF-36, Visual Analog Scale (VAS) Pain, and VAS Satisfaction. METHODS: In the ProDisc-L IDE trial patients with a BMI greater than 40 were excluded from the study. The 161 patients that received the device were divided into 4 groups based on BMI: less than or equal to 20; between 20 and 29 (20 to 29); 29 to 35; and greater than or equal to 35. Pre-operative and post-operative assessment was performed at 6 weeks, 3, 6, 12, 18, and 24 months. RESULTS: Demographics were similar between each of the four subgroups. The largest percentage of women and men were in the BMI 20 to 29 group (70% women, 60% men). Operative level, smoking status, age and length of hospital stay were all similar between the four groups. Significant differences were seen between the groups when examining blood loss and operative time. The decrease in ODI score was not statistically different between the four BMI groups [ (less than 20) 24.0618.42; (20 to 29) 29.9623.32; (29 to 35) 25.4622.4; (greater than 35) 37.0627.54; p50.5840 ]. Similarly, the change in VAS Pain scores [ (less than 20) 25.6629.47; (20 to 29) 43.4631.62; (29 to 35) 29.8630.73; (greater than 35) 50.6631.44 ] and VAS Satisfaction scores [(less than 20) 75.43622.77; (20 to 29) 78.60627.99; (29 to 35) 71.09632.32; (greater than 35) 71.11640.49] were not found to be significant (p50.0709, p50.5860 respectively). Assessment of VAS Improvement also indicated a non-significant difference (p50.7681) between the four BMI groups. CONCLUSIONS: At 2 years follow-up it appears BMI does not have an effect on the clinical results and overall success of a patient following lumbar TDR or circumferential fusion. FDA DEVICE/DRUG STATUS: ProDisc-L: Approved for this indication.
workers’ compensation status. In a focus on objective outcomes relevant to a workers’ compensations setting, a recent study has reported returnto-work (RTW) rates of 36% at an average of 2 years following fusion surgery. However, the combination of spinal fusion with postoperative rehabilitation in relation to treatment outcomes has rarely been studied. PURPOSE: To compare objective socioeconomic outcomes of treatment in chronic disabling occupational spinal disorders (CDOSD) for the combination of spinal fusion surgery plus functional restoration, compared with rehabilitation alone.To compare key outcomes with historic lumbar fusion with usual aftercare from a major state workers’ compensation setting. STUDY DESIGN/SETTING: A prospective cohort study of consecutive patients undergoing spinal fusion (F) procedures before functional restoration for CDOSD in an outpatient interdisciplinary rehabilitation setting, vs. all other CDOSD patients not having a fusion (NF) from the same cohort. PATIENT SAMPLE: A consecutive cohort of 3066 CDOSD patients admitted to a functional restoration program were studied prospectively. The F group (N5383) underwent spine fusion, while the remaining 2683 patients did not have a fusion, but may have had other types of spinal surgery. OUTCOME MEASURES: Relevant socioeconomic outcomes were collected via a structured one-year post-rehabilitation interview, including RTW; work retention; healthcare utilization; new surgeries; new injury claims; case settlement; and Social Security Disability Income (SSDI) status. METHODS: All patients were totally or partially disabled before admission to an intensive, medically-supervised, functional restoration program combining quantitatively-directed exercise progression with a multimodal disability management approach. RESULTS: Initial analyses demonstrated that the NF group had a statistically significant advantage in RTW (88% vs. 81%), work retention 1 year after treatment (82% vs. 74%), and was less likely to seek healthcare from a new provider (24% vs. 35%) or to have SSDI (3% vs. 10%). However, after adjusting statistically for demographic differences and comorbid depression, all significant outcome differences disappeared, and the two groups were statistically similar. Key outcome variables for the lumbar fusion cohort also stood in stark contrast to valid historic controls of lumbar fusion with usual care. The outcomes included RTW of 32–36% and reoperation rates of 23% for usual care after fusion, versus 79% RTW rates and 3% reoperation rates for the functional restoration group. CONCLUSIONS: These results indicate that spinal fusion surgical patients, if administered appropriate postoperative rehabilitation, demonstrate highly satisfactory outcomes that are comparable to patients who have not undergone fusions after work-related injuries. These outcomes are also superior compared to historic controls of fusion with usual postoperative care. The overall conclusion of this study is that poor fusion outcomes in CDOSD patients may be, at least partially, related to patient selection or to inadequate attention to postoperative rehabilitation strategies. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.237
doi: 10.1016/j.spinee.2007.07.236
P46. Excellent Objective Spine Fusion Outcomes if Combined with Optimum Functional Restoration in Occupational Spinal Disorders Brian Theodore, MS1, Tom Mayer, MD2, Robert Gatchel, PhD1; 1 University of Texas at Arlington, Arlington, TX, USA; 2Productive Rehabilitation Institute of Dallas for Ergonomics, Dallas, TX, USA BACKGROUND CONTEXT: Controversy exists over the relationship between spine fusion surgery and successful therapeutic outcomes. Systematic reviews over the last two decades report a variety of competing outcomes, thus making it difficult to compile evidence in a systematic and objective manner. Additionally, many studies do not take into account
P47. Outcomes of Pedicle Subtraction Osteotomies for Fixed Sagittal Imbalance Eric Buchl, MPAS, PA-C1, Alexis Shelokov, MD2, Jeff Ganer1, Richard Hostin, MD1; 1Consulting Orthopedists, Plano, TX, USA; 2Baylor Scoliosis Center, Plano, TX, USA BACKGROUND CONTEXT: In recent years there has been an aggressive trend to correct fixed sagittal plane imbalance with a single level pedicle subtraction osteotomie. Historical treatment consisted of either multiple Smith-Petersen osteotomies or anterior and posterior osteotomie. The present goal is to demonstrate the effectiveness of pedicle subtraction osteotomie to correct fixed sagittal plane imbalance.
Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S PURPOSE: The purpose of this study is to analyses clinical, radiographic, and complications of pedicle subtraction osteotomies (PSO). STUDY DESIGN/SETTING: Chart and radiographic review of a single surgeon’s patient, sequential cohort was carried out to identify: radiogafic outcomes, complications, and clincin outcomes. PATIENT SAMPLE: Patients who underwent PSO for sagittal imbalance greater then 10 cm were included in the cohort. OUTCOME MEASURES: (1) Identified radiographic outcomes (2) Surgical Complications (3) Pseudarthrosis rate (4) SRS-22 (4) Oswestry questioner. METHODS: A single surgeon consecutive patient cohort of fixed sagittal imbalance (C7-S1O10 cm) was analyzed for demographic data, anesthetic risk factors, peri-operative data, and complications. Radiograph analyses included pre-operatively, post-operatively and last follow up. Clinical outcomes included Oswestry questionnaire and the SRS questionnaire. RESULTS: Eighteen patients, 15 female and 3 males with an average age of 56.0 (range, 19.8–73.4y) with fixed sagittal imbalance were treated with PSOs by a single surgeon with minimal one year follow up, average 2.4 years (range, 1.0–4.1y) were included in the study. Average operative time for all procedures was 5.7 hours (range, 2.6–10.9h) with an average estimated blood loss of 2902cc (range, 440–9000cc). At most recent follow up overall sagittal vertical axes improved 76.6% from 13.9cm (range, 10.3 to 19.0cm) to 3.3cm (range, 3.7 to 11.8cm); with an average lumbar lordosis improvement from 29 degrees (range, 2 to 61d) to 46 degrees (range, 16-82d). Early complications included 7 dural tears, 1 stenosis requiring surgical decompression, 1 epidural hematoma requiring surgical decompression, 1 nerve root injury with full recovery by 3 months, 1 adjacent segment fracture, and 1 acute hardware failure. Late complications included 2 Pseudarthrosis, 1 hip flexor contractor related to Parkinsonism Associated Spinal Deformity (PASD), 0 wound infections, 0 permanent neurologic deficits. SRS questionnaire at most recent follow up were: overall 3.21, Self image/appearance 3.04, satisfaction 3.88, pain 3.04, function/ activity 2.94, and mental health 3.38. CONCLUSIONS: As previous described in the literature PSO is an effective means to correct fixed sagittal imbalance and achieve a large amount of correction at a single level. Our cohort is consistent with previous studies; patients maintained good correction at minimum of one year follow up and good clinical results. Based on this cohort PSO remains a superior tool to correct fixed sagittal imbalance. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.238
P48. The Effect of Body Mass Index on Lumbar Lordosis on the Jackson (OSI) Frame Justin Bundy1, Norman Chutkan, MD2, Hiatao Zhou2; 1Medical College of Georgia, Augusta, GA, USA; 2GA, USA BACKGROUND CONTEXT: Studies have investigated patient positioning, various operative frames and there effect on sagittal alignment. However, there is a paucity of information regarding patient selection and body habitus as it relates to intra-operative alignment. PURPOSE: A prospective evaluation to determine if body mass index (BMI) influences the degree of intra-operative lumbar lordosis in patients undergoing operative treatment on the Orthopedic Systems Incorporated (OSI; Jackson) frame. STUDY DESIGN/SETTING: From July 2006 to December 2006, 25 consecutive patients undergoing posterior spinal instrumentation and fusion on the OSI frame at one hospital under the supervision of the senior author were included. PATIENT SAMPLE: 25 consecutive patients were included all undergoing posterior spinal instrumentation and fusion.
105S
METHODS: Patients were radiographed pre-op standing. Radiographs were taken with arms over head and in a relaxed standing position. They were positioned in a standard manner by the same attending surgeon and lateral radiographs obtained prior to surgical prepping.Chest, iliac, and thigh pads were positioned and knees were placed in 15 degrees of flexion with feet over a pillow. Arms were placed to sides with elbows flexed and shoulders externally rotated. Intervertebral body angle measurements were obtained from L1-S1 using the method of Cobb simultaneously by two treating surgeons. All patients were weighed on a single scale and height measured. Changes in angle measurements were compared to BMI and statistical analysis applied. RESULTS: Mean standing lordosis of 51.6 with a range of 20–75 degrees. Mean prone lordosis of 60.7 with a range of 34-80 on the Jackson frame. Mean BMI of 32.9 with a range of 21–49. Mean change in degrees 9.1 with a range of 0–17 degrees. No differences between sexes (pO0.05) ANOVA was used to determine if BMI infuenced lordosis on the Jackson frame and an F value of 9.53709 with a p!0.00802 was found. Using linear regression a multiple regression correlation coefficient of 0.63655 was found. CONCLUSIONS: The current study is the first in which patient selection and use of the OSI frame has been evaluated. These data suggest that BMI influences lumbar lordosis on the OSI frame and that care must be used when dealing with a population with large BMI on the OSI frame FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.239
P49. Monitoring for Ischemic Optic Neuropathy During Prone Spine Surgery? Pupillometry and Retinal Imaging Henry Bennett, PhD1, Geordie Grant, MD1, Ming Xiong, MD1, Roger Turbin, MD1, Leslie Osei-Tutu, MD1, Robert Heary, MD1; 1 UMDNJ, Newark, NJ, USA BACKGROUND CONTEXT: Postoperative visual loss (POVL) is a rare but devastating and poorly understood complication usually affecting longer prone spine surgery patients. The primary presentation is posterior optic neuropathy with bilateral visual loss which does not resolve. In a review of 93 spine cases, longer surgeries with higher blood loss and fluid replacement were partially descriptive of POVL while blood pressure was not (1). PURPOSE: The purpose was to examine changes to the eyes and optic nerve function during prone spine surgery of four hours duration or greater. STUDY DESIGN/SETTING: This is an ongoing prospective, randomized control study of optic and visual system changes across two Jackson table positions- flat or slightly head elevated.The present report is of the feasibility of light flash evoked pupillometry (LVEP) during high-dose remifentanil infusion which produces a profound miosis. PATIENT SAMPLE: The study is designed for 32 patients, 16 each in one of two table positions, who are undergoing prone lumbar spine surgery scheduled for at least four hours. OUTCOME MEASURES: 1. Intraoperative changes over time of intraocular pressure (IOP), results of retinal digital photography (RDP), and changes in latency and amplitude to LFEP. METHODS: A modified Dupaco ‘‘Proneview’’ helmet system frame affords access to the eyes from beneath the Jackson table in the prone position (2). Hourly measurements included IOP (Medtronic TonoPen XL) with contact lens, dilated (tropicamide 1%), RDP (Nidex NM200), and LFEP (NeurOptics). RESULTS: Two patients required L3-S1 amd T11-S1 re-instrumentation and underwent induction with midazolam, fentanyl, lidocaine and propofol followed by cisastracurium. Maintenance anesthesia consisted of remifentanil (0.05–0.16 mcg/kg/min) and cisastracurium (1.5 mcg/kg/min) infusions with isoflurane (0.5-0.8% ET). The patients required 5.1–6.5L crystalloid and 500 ml albumin with EBL of 1.6–1.8L and 400–750 ml cell saver return over the 6–6:30 hr durations of surgery. LFEP latencies and amplitudes remained stable throughout (Figs. 1–2).