- Email: [email protected]
P119. Sacral Insufficiency Fractures Caudal to Instrumented Posterior Lumbosacral Arthrodesis
140S
Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S
significant difference in the recovery rate of JOA score between Group-O (74.4%) and Group-NO (72.7%). CONCLUSIONS: Correction loss of the radiographic parameters except %PDH was significantly greater in the patients with osteoporosis than those without. However, no significant correlation between radiographical and clinical results was indicated. It was clearly demonstrated that osteoporosis significantly contributed to postoperative correction loss of the reconstructed spine by TLIF using Brantigan I/F cages in postmenopausal women. To deeply understand the clinical significance of postoperative correction loss, further study with longer follow-up is necessary. FDA DEVICE/DRUG STATUS: Brantigan I/F cage: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.325
P117. Management of Multilevel Cervical Spondylotic Myelopathy (CSM) by Posterior Decompression and Instrumented Fusion: Indications, Results, and Outcomes in a Series of 93 Cases Arvind Kulkarni, MS (Orth) D’Orth FCPS1, Eric Massicotte, MD, MSc, FRCSC2, Julio Furlan, MD, MBA, PhD2, Michael Fehlings, MD, PhD, FRCS (C)2; 1Gokak, Karnataka, India; 2Toronto Western Hospital, Ontario, Canada BACKGROUND CONTEXT: While cervical laminectomy and instrumented fusion is an increasingly used treatment option for CSM, surprisingly few outcomes data are available regarding this approach. PURPOSE: Analysis of a consecutive series of 103 cases that underwent cervical laminectomy and instrumented fusion for CSM. STUDY DESIGN/SETTING: Retrospective cohort analysis of a consecutive series of 103 cases that underwent cervical laminectomy and instrumented fusion for CSM. Sex, age, diabetes mellitus (DM), hypertension, postoperative complications, and smoking were considered potential co-variates. PATIENT SAMPLE: Ten patients were excluded from the analysis due to lack of follow-up data, the co-existence of cervical dystonia, or combined anterior/posterior surgery. There were two perioperative deaths (2%). Ninety-one patients had complete Nurick data (59 M, 32 F; ages: 33 to 88 years). OUTCOME MEASURES: Nurick scale. METHODS: The Nurick scale was the principal outcome measure used to assess neurological improvement. The Charlson Index was used to quantify comorbidities. Data were analyzed using Fisher Exact test, Mantel-Haenszel chi-square test, paired t test, Mann-Whitney U test, and multivariate analysis. RESULTS: At final follow-up (mean 17 months), 50, 34, and 5 patients had a better, unchanged, or worsened Nurick score respectively. The postoperative Nurick scores (2.460.2) significantly improved over the preoperative Nurick scores (3.260.2, p!.0001). Postoperative complications occurred in 22.8% of the patients. Diabetics had worse baseline and follow-up Nurick scores than nondiabetic patients (p5.022). Using multivariable analysis (R250.763, F513.78, p!.0001), the postoperative Nurick score adjusted for baseline (p!.0001) was not significantly affected by sex (p50.079), age (p50.229), diabetes (p50.107), hypertension (p50.33), smoking (p50.849), duration of preoperative symptoms (p50.65), or postoperative complications (p50.834). The mean Charlson Index was not significantly associated with worse outcomes based on Nurick scores. CONCLUSIONS: Despite significant co-morbidities in these patients, multilevel laminectomy and instrumented fusion improves or stabilizes the disability caused by CSM in 95% of patients. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.326
P118. Results From Grade II, III, and IV Spondylolisthesis With Open Reduction and Posterior Lumbar Interbody Fusion Michael Ramsey, MD, FAAOS; West Texas Spine, P.A., Odessa, TX, USA BACKGROUND CONTEXT: Surgical treatment for Grade II, III, and IV spondylolisthesis varies from fusion in situ, fusion with pedicle screws, fusion with pedicle screw and decompression, to fusion with instrumentation and reduction. However, high complication rates and high rates of neurologic injury have been reported for patients undergoing open reduction and fusion with fixation. Unfortunately, few studies have looked at this patient group. PURPOSE: The purpose of this study is to evaluate the efficacy of PLIF with open reduction method, fusion rates, clinical outcome, and complications (including neurologic injury) on Grade II through IV spondylolisthesis. STUDY DESIGN/SETTING: The study was designed to look at Grade II, III, and IV spondylolisthesis that had open reduction with instrumentation and posterior lumbar interbody fusion (PLIF). PATIENT SAMPLE: 20 patients. OUTCOME MEASURES: Independent radiologists using radiographs, CT scans, and MRI were used to determine slip angle, percent of slip, and fusion rates. Clinical outcome was evaluated by pre- and postoperative Prolo scores. METHODS: A prospective review of 20 patients with Grade II, III, and IV spondylolisthesis who underwent open reduction and PLIF by one surgeon using the Alphatec Zodiac reduction pedicle screw and interbody cages. All patients had greater than 1 year follow-up. The patients’ clinical outcome was evaluated by Prolo score and pain level score pre- and postoperatively. All patients had full neurologic evaluation pre- and postoperatively. Fusion was evaluated by independent radiologists using AP and lateral radiographs. If the X-rays were inconclusive, a CT was used to evaluate the fusion. Pre- and postoperative radiographs were reviewed to evaluate slip angle and Meyerding classification (percent slip). A chart review was performed looking at factors affecting outcome. All operative, perioperative, and postoperative complications were recorded. RESULTS: All 20 patients appeared to be fused at 1 year follow-ups. Excellent results were obtained in 15 patients. Good results were obtained in four patients. Fair result was obtained in one patient. No new neurologic injury was noted postoperatively. CONCLUSIONS: Open reduction and PLIF for Grade II, III, and IV spondylolisthesis is a technically demanding procedure with many known complications. However, open reduction and PLIF for Grade II-IV spondylolisthesis appears to be a safe, reasonable procedure for this group of patients, and apppears to have high fusion rates with good clinical outcome. FDA DEVICE/DRUG STATUS: Alphatec Zodiac poly-axial pedicle screw: Approved for this indication. CONFLICT OF INTEREST: Author (MR) Royalties: Alphatec doi: 10.1016/j.spinee.2006.06.327
P119. Sacral Insufficiency Fractures Caudal to Instrumented Posterior Lumbosacral Arthrodesis Eric Klineberg1, Timothy McHenry2, Carlo Bellabarba, MD1, Theodore Wagner, MD1, Jens Chapman, MD1; 1University of Washington, Seattle, WA, USA; 2United States Army, Ft. Sam, Houston, TX, USA BACKGROUND CONTEXT: Sacral insufficiency fracture is a rare and poorly understood complication of lumbosacral arthrodesis. Without a high index of suspicion, this entity can be easily overlooked, causing a delay in diagnosis. Several case reports have described the successful management of these sacral fractures with bracing and medical treatment of osteoporosis. However, sacral insufficiency fractures with significant displacement, sagittal imbalance, neurologic symptoms, or painful nonunion may necessitate surgical stabilization. At our institution, these fractures are preferentially treated by nonoperative means. If these methods fail, stabilization is performed using lumbopelvic fixation.
Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S PURPOSE: To report on a consecutive series of patients who sustained sacral insufficiency fractures after posterior lumbosacral fusions, and describe the subsequent diagnosis and treatment, including instrumented fusion to the pelvis for unstable fractures in osteopenic patients. STUDY DESIGN/SETTING: Retrospective consecutive case series. PATIENT SAMPLE: Nine. OUTCOME MEASURES: Time from index procedure to diagnosis, fracture displacement and angulation, neurological status, treatment, complications, and final ambulatory status. METHODS: Patients were identified by a retrospective review of surgical and outpatient records, with analysis of the complete medical record and radiographs. RESULTS: The nine patients identified had undergone segmental posterior fusion with pedicle screw instrumentation anchored caudally into the sacrum. Sacral insufficiency fracture was recognized on average within 5 weeks in the six patients who had the index procedure performed at our institution. The other three patients referred to our institution had an average delay in diagnosis of 8 months. Two patients underwent immediate fracture stabilization and fusion. One patient had a Roy-Camille type III lesion with 2.5 cm of displacement. The other patient was morbidly obese and could not be managed in a brace. The remaining seven patients were initially treated nonoperatively. Four patients abandoned bracing an average of 3.3 months after initiation of treatment. Failure was defined as unremitting pain, re-fracture after initial healing, neurologic deterioration, and nonunion. For all of the surgical candidates, preoperative kyphosis measured 9.7 degrees and anterolisthesis averaged 10 mm. Postoperative measurement improved to a mean kyphosis of 2.3 degrees and mean displacement of 1.2 mm. All operatively treated fractures healed and the patients regained their ambulatory capacity. There were two complications in the operative group. The first was a loss of fixation and subsequent kyphosis, and the second was an infection with symptomatic hardware that required removal. The three patients who healed without surgery had persistent complaints of postural imbalance necessitating ambulatory aids to maintain their sagittal alignment. These patients had no significant change in sacral fracture alignment. CONCLUSIONS: Sacral insufficiency fractures are an uncommon complication of segmental posterior lumbosacral fixation in osteoporotic patients. They are potentially unstable fractures, and kyphosis and displacement may contribute to persistent problems of pain and postural malalignment. The diagnosis may be difficult and should be considered in the differential diagnosis in patients who do not improve during the postoperative course. Lumbopelvic fixation is a useful salvage treatment modality for patients who fail nonoperative treatment. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.328
P120. The Reliability of Preoperative Supine Radiographs to Predict the Amount of Curve Flexibility in Adolescent Idiopathic Scoliosis Gene Cheh, MD1, Lawrence Lenke, MD2, Yung Joon Kim, MD2, Ronald Lehman, Jr., MD3, Jacob Buchowski, MD2, Craig Kuhns2, Keith Bridwell2; 1Walter Reed Army Medical Center, St. Louis, MO, USA; 2 Washington University in St. Louis, MO, USA; 3Walter Reed Army Medical Center, Washington, DC, USA BACKGROUND CONTEXT: The value of side bending films is important in the classification of AIS, as well as predicting curve flexibility. However, the reproducibility of side-bending films is highly variable depending on the experience of the technologist and the willingness of the patient to perform a maximal bend. PURPOSE: To determine the reliability of supine (SUP) long cassette radiographs as compared with side bending (SB) films in predicting curve flexibility in cases of adolescent idiopathic scoliosis (AIS).
141S
STUDY DESIGN/SETTING: Retrospective study. PATIENT SAMPLE: 575 patients with a diagnosis of operative AIS. OUTCOME MEASURES: (AP), lateral (LAT), side-bending (left and right), and supine preoperative films. METHODS: A total of 575 patients with a diagnosis of operative AIS having scoliosis films including standing long cassette anteroposterior (AP), lateral (LAT), side-bending (left and right), and supine preoperative films were evaluated. All curves were classified according to the Lenke classification. Coronal parameters were measured including: proximal thoracic (PT), main thoracic (MT), and thoracolumbar/lumbar (TL/L) Cobb measurements; as well as sagittal data including T2–5, T5–12, and TL/L measurements. Statistical analysis was performed using Pearson correlation coefficients with significance set at p!.05. Curves were divided into Lenke Types 1 (N5263), 2 (N5118), 3 (N552), 4 (N531), 5 (N557), and Type 6 (N554). Lenke Types 1-4 (Group I-MT Major) were compared with Types 5 and 6 (Group 2-TL/L Major). RESULTS: For Group I, MT supine films were highly predictive of MT SB and TL/L supine (Table 1). Additionally, PT supine films were predictive of PT SB, and PT standing. Based upon these predictors, an equation was derived to predict the value of the side-bending radiographs for each part of the curve. For Group II, MT supine films were also highly predictive of MT SB MT standing TL/L supine films and TL/L SB and TL/L standing (Table 2). Additionally, PT supine films were predictive of PT SB and PT standing. Contingency table analysis for Group I resulted in a strong statistical ability to predict a nonstructural PT curve (PPV50.864) and also a nonstructural TL/L curve (PPV50.916). Similarly, in Group II, we found a strong statistical ability to predict a nonstructural PT curve (PPV50.982) and also a nonstructural MT curve (PPV50.833). CONCLUSIONS: A single preoperative supine X-ray is highly predictive of side-bending radiographs and can be used as an adjunct to predicting curve type, flexibility, and whether or not a curve is structural or nonstructural. Thus, this singular, reproducible and non-effort related radiograph can potentially replace the need for dual side-bending films. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.329
P121. Biomechanical Evaluation of a Modified Cervical Laminoplasty Mei Wang1, Toru Yokoyama, MD, PhD2, T. Numasawa, MD, PhD2, Satoshi Toh, MD, PhD2, Linda McGrady, BS1, Jeffrey Toth, PhD1; 1 Medical College of Wisconsin, Milwaukee, WI, USA; 2Hirosaki University, Hirosaki, Japan BACKGROUND CONTEXT: Laminoplasty has become a widely accepted treatment for multi-segmental cervical myelopathy. However, the procedure usually involves stripping of the extensor musculature and insertions to the spinous processes. Some believe that disruption of this major dynamic stabilizer contributes to incidence of persistent axial pain and the loss of cervical lordosis. To preserve extensor insertion into C2, a modified procedure has been proposed that combines C4-C7 laminoplasty with C3 laminectomy. Preliminary clinical study has reported good outcomes, but it is unclear how much destabilization this modified procedure brings to the cervical spine. PURPOSE: The objective of this study was to compare the immediate postoperative stability of the cervical spine after three multi-segment decompression procedures: conventional C3–C7 laminoplasty, modified laminoplasty, and C3-C7 laminectomy. STUDY DESIGN/SETTING: In vitro testing of cadaveric specimens in a biomechanics laboratory of academic setting. PATIENT SAMPLE: Ten unembalmed human cadaveric cervical spines. OUTCOME MEASURES: Range of motion analysis.
Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S
significant difference in the recovery rate of JOA score between Group-O (74.4%) and Group-NO (72.7%). CONCLUSIONS: Correction loss of the radiographic parameters except %PDH was significantly greater in the patients with osteoporosis than those without. However, no significant correlation between radiographical and clinical results was indicated. It was clearly demonstrated that osteoporosis significantly contributed to postoperative correction loss of the reconstructed spine by TLIF using Brantigan I/F cages in postmenopausal women. To deeply understand the clinical significance of postoperative correction loss, further study with longer follow-up is necessary. FDA DEVICE/DRUG STATUS: Brantigan I/F cage: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.325
P117. Management of Multilevel Cervical Spondylotic Myelopathy (CSM) by Posterior Decompression and Instrumented Fusion: Indications, Results, and Outcomes in a Series of 93 Cases Arvind Kulkarni, MS (Orth) D’Orth FCPS1, Eric Massicotte, MD, MSc, FRCSC2, Julio Furlan, MD, MBA, PhD2, Michael Fehlings, MD, PhD, FRCS (C)2; 1Gokak, Karnataka, India; 2Toronto Western Hospital, Ontario, Canada BACKGROUND CONTEXT: While cervical laminectomy and instrumented fusion is an increasingly used treatment option for CSM, surprisingly few outcomes data are available regarding this approach. PURPOSE: Analysis of a consecutive series of 103 cases that underwent cervical laminectomy and instrumented fusion for CSM. STUDY DESIGN/SETTING: Retrospective cohort analysis of a consecutive series of 103 cases that underwent cervical laminectomy and instrumented fusion for CSM. Sex, age, diabetes mellitus (DM), hypertension, postoperative complications, and smoking were considered potential co-variates. PATIENT SAMPLE: Ten patients were excluded from the analysis due to lack of follow-up data, the co-existence of cervical dystonia, or combined anterior/posterior surgery. There were two perioperative deaths (2%). Ninety-one patients had complete Nurick data (59 M, 32 F; ages: 33 to 88 years). OUTCOME MEASURES: Nurick scale. METHODS: The Nurick scale was the principal outcome measure used to assess neurological improvement. The Charlson Index was used to quantify comorbidities. Data were analyzed using Fisher Exact test, Mantel-Haenszel chi-square test, paired t test, Mann-Whitney U test, and multivariate analysis. RESULTS: At final follow-up (mean 17 months), 50, 34, and 5 patients had a better, unchanged, or worsened Nurick score respectively. The postoperative Nurick scores (2.460.2) significantly improved over the preoperative Nurick scores (3.260.2, p!.0001). Postoperative complications occurred in 22.8% of the patients. Diabetics had worse baseline and follow-up Nurick scores than nondiabetic patients (p5.022). Using multivariable analysis (R250.763, F513.78, p!.0001), the postoperative Nurick score adjusted for baseline (p!.0001) was not significantly affected by sex (p50.079), age (p50.229), diabetes (p50.107), hypertension (p50.33), smoking (p50.849), duration of preoperative symptoms (p50.65), or postoperative complications (p50.834). The mean Charlson Index was not significantly associated with worse outcomes based on Nurick scores. CONCLUSIONS: Despite significant co-morbidities in these patients, multilevel laminectomy and instrumented fusion improves or stabilizes the disability caused by CSM in 95% of patients. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.326
P118. Results From Grade II, III, and IV Spondylolisthesis With Open Reduction and Posterior Lumbar Interbody Fusion Michael Ramsey, MD, FAAOS; West Texas Spine, P.A., Odessa, TX, USA BACKGROUND CONTEXT: Surgical treatment for Grade II, III, and IV spondylolisthesis varies from fusion in situ, fusion with pedicle screws, fusion with pedicle screw and decompression, to fusion with instrumentation and reduction. However, high complication rates and high rates of neurologic injury have been reported for patients undergoing open reduction and fusion with fixation. Unfortunately, few studies have looked at this patient group. PURPOSE: The purpose of this study is to evaluate the efficacy of PLIF with open reduction method, fusion rates, clinical outcome, and complications (including neurologic injury) on Grade II through IV spondylolisthesis. STUDY DESIGN/SETTING: The study was designed to look at Grade II, III, and IV spondylolisthesis that had open reduction with instrumentation and posterior lumbar interbody fusion (PLIF). PATIENT SAMPLE: 20 patients. OUTCOME MEASURES: Independent radiologists using radiographs, CT scans, and MRI were used to determine slip angle, percent of slip, and fusion rates. Clinical outcome was evaluated by pre- and postoperative Prolo scores. METHODS: A prospective review of 20 patients with Grade II, III, and IV spondylolisthesis who underwent open reduction and PLIF by one surgeon using the Alphatec Zodiac reduction pedicle screw and interbody cages. All patients had greater than 1 year follow-up. The patients’ clinical outcome was evaluated by Prolo score and pain level score pre- and postoperatively. All patients had full neurologic evaluation pre- and postoperatively. Fusion was evaluated by independent radiologists using AP and lateral radiographs. If the X-rays were inconclusive, a CT was used to evaluate the fusion. Pre- and postoperative radiographs were reviewed to evaluate slip angle and Meyerding classification (percent slip). A chart review was performed looking at factors affecting outcome. All operative, perioperative, and postoperative complications were recorded. RESULTS: All 20 patients appeared to be fused at 1 year follow-ups. Excellent results were obtained in 15 patients. Good results were obtained in four patients. Fair result was obtained in one patient. No new neurologic injury was noted postoperatively. CONCLUSIONS: Open reduction and PLIF for Grade II, III, and IV spondylolisthesis is a technically demanding procedure with many known complications. However, open reduction and PLIF for Grade II-IV spondylolisthesis appears to be a safe, reasonable procedure for this group of patients, and apppears to have high fusion rates with good clinical outcome. FDA DEVICE/DRUG STATUS: Alphatec Zodiac poly-axial pedicle screw: Approved for this indication. CONFLICT OF INTEREST: Author (MR) Royalties: Alphatec doi: 10.1016/j.spinee.2006.06.327
P119. Sacral Insufficiency Fractures Caudal to Instrumented Posterior Lumbosacral Arthrodesis Eric Klineberg1, Timothy McHenry2, Carlo Bellabarba, MD1, Theodore Wagner, MD1, Jens Chapman, MD1; 1University of Washington, Seattle, WA, USA; 2United States Army, Ft. Sam, Houston, TX, USA BACKGROUND CONTEXT: Sacral insufficiency fracture is a rare and poorly understood complication of lumbosacral arthrodesis. Without a high index of suspicion, this entity can be easily overlooked, causing a delay in diagnosis. Several case reports have described the successful management of these sacral fractures with bracing and medical treatment of osteoporosis. However, sacral insufficiency fractures with significant displacement, sagittal imbalance, neurologic symptoms, or painful nonunion may necessitate surgical stabilization. At our institution, these fractures are preferentially treated by nonoperative means. If these methods fail, stabilization is performed using lumbopelvic fixation.
Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S PURPOSE: To report on a consecutive series of patients who sustained sacral insufficiency fractures after posterior lumbosacral fusions, and describe the subsequent diagnosis and treatment, including instrumented fusion to the pelvis for unstable fractures in osteopenic patients. STUDY DESIGN/SETTING: Retrospective consecutive case series. PATIENT SAMPLE: Nine. OUTCOME MEASURES: Time from index procedure to diagnosis, fracture displacement and angulation, neurological status, treatment, complications, and final ambulatory status. METHODS: Patients were identified by a retrospective review of surgical and outpatient records, with analysis of the complete medical record and radiographs. RESULTS: The nine patients identified had undergone segmental posterior fusion with pedicle screw instrumentation anchored caudally into the sacrum. Sacral insufficiency fracture was recognized on average within 5 weeks in the six patients who had the index procedure performed at our institution. The other three patients referred to our institution had an average delay in diagnosis of 8 months. Two patients underwent immediate fracture stabilization and fusion. One patient had a Roy-Camille type III lesion with 2.5 cm of displacement. The other patient was morbidly obese and could not be managed in a brace. The remaining seven patients were initially treated nonoperatively. Four patients abandoned bracing an average of 3.3 months after initiation of treatment. Failure was defined as unremitting pain, re-fracture after initial healing, neurologic deterioration, and nonunion. For all of the surgical candidates, preoperative kyphosis measured 9.7 degrees and anterolisthesis averaged 10 mm. Postoperative measurement improved to a mean kyphosis of 2.3 degrees and mean displacement of 1.2 mm. All operatively treated fractures healed and the patients regained their ambulatory capacity. There were two complications in the operative group. The first was a loss of fixation and subsequent kyphosis, and the second was an infection with symptomatic hardware that required removal. The three patients who healed without surgery had persistent complaints of postural imbalance necessitating ambulatory aids to maintain their sagittal alignment. These patients had no significant change in sacral fracture alignment. CONCLUSIONS: Sacral insufficiency fractures are an uncommon complication of segmental posterior lumbosacral fixation in osteoporotic patients. They are potentially unstable fractures, and kyphosis and displacement may contribute to persistent problems of pain and postural malalignment. The diagnosis may be difficult and should be considered in the differential diagnosis in patients who do not improve during the postoperative course. Lumbopelvic fixation is a useful salvage treatment modality for patients who fail nonoperative treatment. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.328
P120. The Reliability of Preoperative Supine Radiographs to Predict the Amount of Curve Flexibility in Adolescent Idiopathic Scoliosis Gene Cheh, MD1, Lawrence Lenke, MD2, Yung Joon Kim, MD2, Ronald Lehman, Jr., MD3, Jacob Buchowski, MD2, Craig Kuhns2, Keith Bridwell2; 1Walter Reed Army Medical Center, St. Louis, MO, USA; 2 Washington University in St. Louis, MO, USA; 3Walter Reed Army Medical Center, Washington, DC, USA BACKGROUND CONTEXT: The value of side bending films is important in the classification of AIS, as well as predicting curve flexibility. However, the reproducibility of side-bending films is highly variable depending on the experience of the technologist and the willingness of the patient to perform a maximal bend. PURPOSE: To determine the reliability of supine (SUP) long cassette radiographs as compared with side bending (SB) films in predicting curve flexibility in cases of adolescent idiopathic scoliosis (AIS).
141S
STUDY DESIGN/SETTING: Retrospective study. PATIENT SAMPLE: 575 patients with a diagnosis of operative AIS. OUTCOME MEASURES: (AP), lateral (LAT), side-bending (left and right), and supine preoperative films. METHODS: A total of 575 patients with a diagnosis of operative AIS having scoliosis films including standing long cassette anteroposterior (AP), lateral (LAT), side-bending (left and right), and supine preoperative films were evaluated. All curves were classified according to the Lenke classification. Coronal parameters were measured including: proximal thoracic (PT), main thoracic (MT), and thoracolumbar/lumbar (TL/L) Cobb measurements; as well as sagittal data including T2–5, T5–12, and TL/L measurements. Statistical analysis was performed using Pearson correlation coefficients with significance set at p!.05. Curves were divided into Lenke Types 1 (N5263), 2 (N5118), 3 (N552), 4 (N531), 5 (N557), and Type 6 (N554). Lenke Types 1-4 (Group I-MT Major) were compared with Types 5 and 6 (Group 2-TL/L Major). RESULTS: For Group I, MT supine films were highly predictive of MT SB and TL/L supine (Table 1). Additionally, PT supine films were predictive of PT SB, and PT standing. Based upon these predictors, an equation was derived to predict the value of the side-bending radiographs for each part of the curve. For Group II, MT supine films were also highly predictive of MT SB MT standing TL/L supine films and TL/L SB and TL/L standing (Table 2). Additionally, PT supine films were predictive of PT SB and PT standing. Contingency table analysis for Group I resulted in a strong statistical ability to predict a nonstructural PT curve (PPV50.864) and also a nonstructural TL/L curve (PPV50.916). Similarly, in Group II, we found a strong statistical ability to predict a nonstructural PT curve (PPV50.982) and also a nonstructural MT curve (PPV50.833). CONCLUSIONS: A single preoperative supine X-ray is highly predictive of side-bending radiographs and can be used as an adjunct to predicting curve type, flexibility, and whether or not a curve is structural or nonstructural. Thus, this singular, reproducible and non-effort related radiograph can potentially replace the need for dual side-bending films. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.329
P121. Biomechanical Evaluation of a Modified Cervical Laminoplasty Mei Wang1, Toru Yokoyama, MD, PhD2, T. Numasawa, MD, PhD2, Satoshi Toh, MD, PhD2, Linda McGrady, BS1, Jeffrey Toth, PhD1; 1 Medical College of Wisconsin, Milwaukee, WI, USA; 2Hirosaki University, Hirosaki, Japan BACKGROUND CONTEXT: Laminoplasty has become a widely accepted treatment for multi-segmental cervical myelopathy. However, the procedure usually involves stripping of the extensor musculature and insertions to the spinous processes. Some believe that disruption of this major dynamic stabilizer contributes to incidence of persistent axial pain and the loss of cervical lordosis. To preserve extensor insertion into C2, a modified procedure has been proposed that combines C4-C7 laminoplasty with C3 laminectomy. Preliminary clinical study has reported good outcomes, but it is unclear how much destabilization this modified procedure brings to the cervical spine. PURPOSE: The objective of this study was to compare the immediate postoperative stability of the cervical spine after three multi-segment decompression procedures: conventional C3–C7 laminoplasty, modified laminoplasty, and C3-C7 laminectomy. STUDY DESIGN/SETTING: In vitro testing of cadaveric specimens in a biomechanics laboratory of academic setting. PATIENT SAMPLE: Ten unembalmed human cadaveric cervical spines. OUTCOME MEASURES: Range of motion analysis.