- Email: [email protected]
Lumbar pedicle subtraction osteotomy
Proceedings of the NASS 16th Annual Meeting / The Spine Journal 2 (2002) 3S–44S
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with the initial physical finding of scoliosis. Twenty of the 22 patients had an associated syrinx of variable size. One patient had a scoliosis fusion before recognition of their Chiari 1 malformation and syrinx. Fifteen of the 22 curves were convex to the left, and 7 of 22 were convex to the right. All patients were initially managed with suboccipital decompression, C1 laminectomy, lysis of the arachnoid space and duraplasty followed by layered closure of the wound. The mean follow-up for the series was 3.8 years (range, 3 months to 10 years). Patients were followed with plain radiographs to monitor the scoliosis and serial magnetic resonance imaging to evaluate the effect of the decompression on the syrinx. Results: Table 1 summarizes the response of 21 patients with Chiari 1 malformation and scoliosis to the initial suboccipital decompression. The magnitude of the initial scoliosis was variable; 55% had curves greater than 30 degrees. Fifty-seven percent of curves improved after initial decompression, but 33% worsened. Four of the 21 patients have required fusion for curve progression, with an additional three patients anticipating surgery because of worsening of their curve. Curve progression was greatest for curves greater than 40 degrees at the time of initial presentation. All syrinxes improved with decompression, although the degree of response was variable and difficult to quantify. However, the degree of syrinx improvement did not correlate with curve improvement. There were four complications in the series. One syrinx required shunting after decompression, hydrothorax (1), syringopleural shunt revision (1) and pseudomeningocele repair (1). Table 1 Initial curve (degrees)
Patients
Improved worse
0–20 20–30 30–40 40–50 50 Total
1 8 3 7 2 21
1 8 3 7 2 12
Improved
Worse
1 1
2
1 2
4 1 7
Fused
3 4
*One patient had fusion before recognition of the Chiari malformation and syrinx.
Conclusion: In this series, 57% of patients presenting with scoliosis, Chiari 1 malformation and syrinx, demonstrated improvement in their curve after suboccipital decompression. Improvement in the scoliosis curve was variable and did not have a consistent relationship with either age at initial presentation or curve severity. After initial improvement, some curves will begin to worsen over time, necessitating careful followup until the completion of growth. Curves that are greater than 40 degrees at the time of initial presentation are more likely to progress despite decompression. The response of the syrinx to initial decompression did not predict which curves would be progressive. Early detection and treatment of Chiari 1–related scoliosis remains beneficial, because long-standing significant curves are unlikely to improve after decompression.
Transpedicular decompression and pedicle subtraction osteotomy: review of 101 patients Daniel B. Murrey, MD, Charlotte, NC, USA; Samuel J. Chewning, MD, Statesville, NC, USA; Craig C. Brigham, MD, Frederick Finger, MD, Charlotte, NC, USA; Gary M. Kiebzak, MD, Houston, TX, USA The “eggshell procedure” was originally described as a technique to allow anterior decompression and posterior fusion through a single transpedicular approach. The use of this technique has broadened to encompass a range of procedures from simple transpedicular decompression and posterior fusion to transpedicular vertebrectomy and strut grafting with posterolateral fusion or pedicle subtraction (closing wedge) osteotomy with posterolateral fusion. It is typically used for the treatment of acute trauma, deformity, tumor or infection. The common thread remains that all of these procedures are done through a single posterior midline incision, anterior spinal canal decompression is carried out through a transpedicular approach and it is accompanied by a posterior or posterolateral fusion. All or part of the anterior or posterior elements may be removed and strut grafting may or may not be
necessary, depending on the goals of the particular case. The procedure is reserved for complex reconstructive problems and frequently is used as a salvage technique. In this study our objective was to determine the effectiveness or decompression and neurological outcome, the effectiveness of correction, the stability of fusion, the safety of the procedure and its complication rates and the overall patient outcomes. Independent chart review of 101 consecutive cases between 1990 and 1998 was carried out. Those available underwent patient interview, physical examination and radiographic analysis. Outcome data were collected using SF-36 and SRS outcome instruments. Of the 101 patients, 76 had 2-year or greater follow-up with an average of 6.0 1.9 years. Fourteen patients died during the follow-up period, and 26 were lost to follow-up. The remaining 61 were interviewed, examined and radiographed. Chart review was performed on all 101 patients. Fortytwo patients had the procedure for acute trauma, 37 for deformity and 22 for tumor or infection. Regarding fusion and correction of deformity, all patients achieved solid fusion radiographically and no loss of correction over time was identified. In patients with preoperative kyphosis, there was a tendency to undercorrect the sagittal alignment, with some patients retaining a slightly kyphotic posture. No overcorrection was identified. Hardware failure rate was less than 3%. Systemic complication rates were low, with a pulmonary complication rate of less than 4%. There were no perioperative deaths. Blood loss averaged 1,989 1,899 cc, with higher losses seen in deformity cases and lower losses seen with acute trauma. Outcomes measured using the SF-36 and SRS questionnaires showed sex differences when correlating against length of follow-up. For women, selfimage and general function scores decreased with increasing time from surgery. For men, function-related domains improved with increasing time from surgery. For both men and women, physical function, role physical, bodily pain and general health were significantly lower than normal subjects of the same age, even at longer-term follow-up. Results for social, emotional and mental health domains were not significantly different from normal. Outcomes measured in terms of pain control and narcotic use showed approximately two-thirds of patients using only NSAIDs or no pain medication. Less than 20% of patients used narcotics frequently. Patient satisfaction was high, with 92.9% of patients relatively or completely satisfied with their results, and 98% would recommend the procedure to another patient in similar circumstances. Overall, the results suggest that this procedure is a reliable and safe way to achieve anterior decompression of the spinal canal and posterior stabilization through a single approach. Lumbar pedicle subtraction osteotomy: clinical and radiographic Anton A. Thompkins, MD, Courtney W. Brown, MD, David H. Donaldson, MD, John L. Brugman, MD, Douglas C. Wong, MD, James S. Gebhard, MD, Barbara J. Muff, RN, BSN, ONC, Golden, CO, USA Introduction: Patients that have the diagnosis of “flat back syndrome” often have chronic debilitating back pain secondary to degenerative changes and global imbalance. The fixed sagittal imbalance places the spinal musculature at a mechanical disadvantage, increasing muscle fatigue, spasms and therefore pain. This difficult problem has been addressed in the past with either an anteroposterior spinal osteotomy and fusion or a SmithPeterson osteotomy. By the very nature of these procedures, the spinal cord can be placed at risk secondary to the lengthening of the anterior spinal column. Pedicle subtraction osteotomy achieves a rebalanced spine without lengthening neural elements. Purpose: The purpose of this review is to report the clinical and radiographic outcome of patients who have undergone pedicle subtraction osteotomy in order to achieve significant correction of sagittal and coronal imbalance. Materials and methods: The clinical course and radiographic analysis of 27 consecutive patients who underwent pedicle subtraction osteotomy were evaluated. The clinical evaluation included operative time, blood loss, hospital stay, complications and the pre- and postoperative pain medi-
Proceedings of the NASS 16th Annual Meeting / The Spine Journal 2 (2002) 3S–44S cation use. This information was gathered from both clinic and hospital charts and by direct contact with the patients. The radiographic analysis compared preoperative sagittal and coronal balance with postoperative sagittal and coronal balance. In addition, the amount of correction obtained at the osteotomy site and the overall lumbar sagittal contour change from preand postoperative radiographs were evaluated. The coronal balance was measured from C7 to the middle of the sacrum on an AP film with a plum line. The overall sagittal balance was measured from the anterior/inferior edge of C7 to the posterior aspect of S1 again, with a plum line. The osteotomy correction was measured using the Cobb angle technique from the end plate immediately above and below the operative level. The degree of lumbar lordosis was measured from the inferior end plate of T12 to the superior end plate of S1. Results: Sixteen female and 11 male patients underwent pedicle subtraction osteotomy between 1996 and 2000. The average age was 49 years, with the mean number of previous spinal operations of three. Even in the multiply operated spine, pedicle fixation was obtained 100% of the time in the lumbar spine to aid in maintaining the appropriated sagittal contour. The average blood loss was 1,116 cc and the average operative time was 6 hours and 45 minutes, with a mean hospital stay of 6 days. The average preoperative coronal and sagittal imbalance were 4.38 cm and 12.22 cm, respectively. The postoperative correction on the immediate follow-up showed coronal and sagittal balance of 1.84 cm and 3.42 cm, respectively. This represents a 58% correction in the coronal plane and a 72% correction in the sagittal plane. This correction was maintained at the latest follow-up with only a .09 cm average loss of correction in the coronal plane and .04 cm average loss of correction in the sagittal plane. This loss of correction is well within measurement error and is considered to be negligible. The average follow-up examination was 15 months from the index procedure. The correction obtained through the osteotomy site was 31 degrees on average with an increase in lumbar lordosis from 28 degrees preoperatively to 49 degrees postoperatively. The overall satisfaction with surgery was quite high, even with nine patients having complications. There were no incidences of spinal cord injury or nerve root loss. There were four infections (one deep, three superficial), which resolved with the appropriate antibiotic course. There were four cases of pseudarthrosis requiring a second operation, all of which went on to a solid union. In evaluating the amount of pain medicines used pre- and postoperatively, 60% of patients went from narcotic use to only an anti-inflammatory agent or nothing for pain management. Seventeen percent of the patients still used an occasional narcotic pain pill to manage their back pain, but all patients had an overall decrease in the use of pain medicines. Conclusion: Pedicle subtraction osteotomy is a safe and effect treatment for patients who have flat back syndrome. It is the authors’ belief that pedicle subtraction osteotomy is a safer approach than the previously described methods of treating this problem. Pedicle subtraction osteotomy can be performed on patients who have had multiple spinal operations. This simple posterior procedure offers excellent radiographic and clinical improvements with limited complications. The role of measured resistance exercises in adolescent scoliosis Vert Mooney, MD, Allison Brigham, BS, San Diego, CA, USA Purpose: To document the effect of progressive strength training in torso rotation in individuals with adolescent scoliosis. Preliminary work at our center has demonstrated that all scoliotic adolescents had an asymmetry of rotation strength measured on specialized equipment, which isolates the torso rotation strength. In addition, surface electrode electromyograms had demonstrated inhibition of lumbar paraspinal muscles. The inhibition and strength corrected after several sessions of isolated progressive exercise training. Methods: Twenty-five adolescents (23 females, 2 males) with scoliosis ranging from 15 to 41 in their major curve were treated with a progressive resistive training program for torso rotation. They were treated twice a week until skeletal maturity or documented reduction of curve. None were braced during the period of treatment. Starting resistance was one third of body weight. Equal resistance was used for both left and right rotation, al-
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though initially rotation was weaker in one direction compared with the other. Once able to carry out 20 repetitions, the resistance was increased about 5%. Rotation range was increased as tolerated. Patients with surgical level of curves did not respond and were not followed. Results: Eighteen of 25 demonstrated curve reduction. Although there was some fluctuation, none of the rest had a persistent increase in curve. Pretraining average range was 28.2 13.2. Posttraining range was 23.0 14.1. The percentage improvement was 20% 23.3%. There was a 132.5% (61.4%) increase in dynamic strength. None went on to surgery or bracing. Discussion: Based on the demonstration of strength and asymmetry in rotation and inhibited lumbar extensor muscle activity, it is rational to place adolescents with scoliosis into a progressive resistance training program. In this small series, it offered notable benefit with documented control of curve progression. Parents were pleased that an active intervention was provided rather than “watch and wait” typical of presurgical adolescent scoliotic care. Lack of efficacy of exercise in previous studies may be because there was a lack of specific muscle training and measurement. No exercise program using equipment has previously been reported. Adolescent idiopathic scoliosis, bracing and the Hueter-Volkmann principle Frank P. Castro, MD, Amy Young, Richard T. Holt, MD, Mohammed E. Majd, MD, Louisville, KY, USA Purpose: Asymmetric chondrogenesis, in accordance with the HueterVolkmann principle, is frequently cited as a potential cause for adolescent idiopathic scoliosis (AIS). Brace treatment may reverse the abnormal forces across the apical vertebrae. The purpose of this investigation was to determine whether long-term brace treatment stimulated asymmetric chondrogenesis in the apical three vertebrae in patients with AIS. Three male and 38 female patients met the following inclusion criteria for the study: skeletal immaturity (Risser 0 or 1) at initial presentation, a major curve between 20 and 40 degrees, treatment consisting of a thoracolumbosacral orthosis, a minimum of 2 years of follow-up and documented skeletal maturity at final follow-up (Risser 5). Methods: Cobb angles and concave-to-convex height ratios of the apical three vertebral bodies were measured when bracing was indicated, in the brace, and after skeletal maturity. Measurements were compared by a repeated-measures analysis of variance statistic. Results: Cobb measurements improved 50% (p.0001) with the application of a brace. Immediate radiographic improvements were also measured in the cephalad (p.0027) and caudal (p.0004) apical height ratios when the brace was initially applied. On average, Cobb measurements increased six degrees after an average of 41 months of follow-up (p.001). Vertebral body remodeling by asymmetric chondrogenesis, as evidenced by changes in the concave-to-convex height ratios, were not appreciated. Conclusion: Application of a brace to patients with AIS resulted in immediate radiographic improvements in the Cobb measurements and concaveto-convex height ratios. Structural changes in vertebral body shape resulting from asymmetric chondrogenesis were not appreciated. Thus, the HueterVolkmann principle appears not to be applicable in patients with AIS with curves between 20 and 40 Cobb angle degrees treated with a brace. The Million Visual Analogue Scale: its utility for predicting outcomes after tertiary rehabilitation Tom Mayer, MD, Timothy Proctor, PhD, Robert J. Gatchel, PhD, Dallas, TX, USA Introduction: The Million Visual Analogue Scale (MVAS) [1] is a 15item visual analog measure of spinal pain disability. This instrument produces a total functional disability score ranging from 0 to 150. Like other “disability inventories,” such as the Oswestry and the Roland-Morris, the MVAS differs from a “pain inventory” in that the focus is on disability and function, as opposed to self-reported pain. The MVAS may be the strongest functional rating scale, because all questions relate to the patient’s ability to perform activities of daily living. In addition, this instrument has the advantage of a visual analog format, which is typically considered
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with the initial physical finding of scoliosis. Twenty of the 22 patients had an associated syrinx of variable size. One patient had a scoliosis fusion before recognition of their Chiari 1 malformation and syrinx. Fifteen of the 22 curves were convex to the left, and 7 of 22 were convex to the right. All patients were initially managed with suboccipital decompression, C1 laminectomy, lysis of the arachnoid space and duraplasty followed by layered closure of the wound. The mean follow-up for the series was 3.8 years (range, 3 months to 10 years). Patients were followed with plain radiographs to monitor the scoliosis and serial magnetic resonance imaging to evaluate the effect of the decompression on the syrinx. Results: Table 1 summarizes the response of 21 patients with Chiari 1 malformation and scoliosis to the initial suboccipital decompression. The magnitude of the initial scoliosis was variable; 55% had curves greater than 30 degrees. Fifty-seven percent of curves improved after initial decompression, but 33% worsened. Four of the 21 patients have required fusion for curve progression, with an additional three patients anticipating surgery because of worsening of their curve. Curve progression was greatest for curves greater than 40 degrees at the time of initial presentation. All syrinxes improved with decompression, although the degree of response was variable and difficult to quantify. However, the degree of syrinx improvement did not correlate with curve improvement. There were four complications in the series. One syrinx required shunting after decompression, hydrothorax (1), syringopleural shunt revision (1) and pseudomeningocele repair (1). Table 1 Initial curve (degrees)
Patients
Improved worse
0–20 20–30 30–40 40–50 50 Total
1 8 3 7 2 21
1 8 3 7 2 12
Improved
Worse
1 1
2
1 2
4 1 7
Fused
3 4
*One patient had fusion before recognition of the Chiari malformation and syrinx.
Conclusion: In this series, 57% of patients presenting with scoliosis, Chiari 1 malformation and syrinx, demonstrated improvement in their curve after suboccipital decompression. Improvement in the scoliosis curve was variable and did not have a consistent relationship with either age at initial presentation or curve severity. After initial improvement, some curves will begin to worsen over time, necessitating careful followup until the completion of growth. Curves that are greater than 40 degrees at the time of initial presentation are more likely to progress despite decompression. The response of the syrinx to initial decompression did not predict which curves would be progressive. Early detection and treatment of Chiari 1–related scoliosis remains beneficial, because long-standing significant curves are unlikely to improve after decompression.
Transpedicular decompression and pedicle subtraction osteotomy: review of 101 patients Daniel B. Murrey, MD, Charlotte, NC, USA; Samuel J. Chewning, MD, Statesville, NC, USA; Craig C. Brigham, MD, Frederick Finger, MD, Charlotte, NC, USA; Gary M. Kiebzak, MD, Houston, TX, USA The “eggshell procedure” was originally described as a technique to allow anterior decompression and posterior fusion through a single transpedicular approach. The use of this technique has broadened to encompass a range of procedures from simple transpedicular decompression and posterior fusion to transpedicular vertebrectomy and strut grafting with posterolateral fusion or pedicle subtraction (closing wedge) osteotomy with posterolateral fusion. It is typically used for the treatment of acute trauma, deformity, tumor or infection. The common thread remains that all of these procedures are done through a single posterior midline incision, anterior spinal canal decompression is carried out through a transpedicular approach and it is accompanied by a posterior or posterolateral fusion. All or part of the anterior or posterior elements may be removed and strut grafting may or may not be
necessary, depending on the goals of the particular case. The procedure is reserved for complex reconstructive problems and frequently is used as a salvage technique. In this study our objective was to determine the effectiveness or decompression and neurological outcome, the effectiveness of correction, the stability of fusion, the safety of the procedure and its complication rates and the overall patient outcomes. Independent chart review of 101 consecutive cases between 1990 and 1998 was carried out. Those available underwent patient interview, physical examination and radiographic analysis. Outcome data were collected using SF-36 and SRS outcome instruments. Of the 101 patients, 76 had 2-year or greater follow-up with an average of 6.0 1.9 years. Fourteen patients died during the follow-up period, and 26 were lost to follow-up. The remaining 61 were interviewed, examined and radiographed. Chart review was performed on all 101 patients. Fortytwo patients had the procedure for acute trauma, 37 for deformity and 22 for tumor or infection. Regarding fusion and correction of deformity, all patients achieved solid fusion radiographically and no loss of correction over time was identified. In patients with preoperative kyphosis, there was a tendency to undercorrect the sagittal alignment, with some patients retaining a slightly kyphotic posture. No overcorrection was identified. Hardware failure rate was less than 3%. Systemic complication rates were low, with a pulmonary complication rate of less than 4%. There were no perioperative deaths. Blood loss averaged 1,989 1,899 cc, with higher losses seen in deformity cases and lower losses seen with acute trauma. Outcomes measured using the SF-36 and SRS questionnaires showed sex differences when correlating against length of follow-up. For women, selfimage and general function scores decreased with increasing time from surgery. For men, function-related domains improved with increasing time from surgery. For both men and women, physical function, role physical, bodily pain and general health were significantly lower than normal subjects of the same age, even at longer-term follow-up. Results for social, emotional and mental health domains were not significantly different from normal. Outcomes measured in terms of pain control and narcotic use showed approximately two-thirds of patients using only NSAIDs or no pain medication. Less than 20% of patients used narcotics frequently. Patient satisfaction was high, with 92.9% of patients relatively or completely satisfied with their results, and 98% would recommend the procedure to another patient in similar circumstances. Overall, the results suggest that this procedure is a reliable and safe way to achieve anterior decompression of the spinal canal and posterior stabilization through a single approach. Lumbar pedicle subtraction osteotomy: clinical and radiographic Anton A. Thompkins, MD, Courtney W. Brown, MD, David H. Donaldson, MD, John L. Brugman, MD, Douglas C. Wong, MD, James S. Gebhard, MD, Barbara J. Muff, RN, BSN, ONC, Golden, CO, USA Introduction: Patients that have the diagnosis of “flat back syndrome” often have chronic debilitating back pain secondary to degenerative changes and global imbalance. The fixed sagittal imbalance places the spinal musculature at a mechanical disadvantage, increasing muscle fatigue, spasms and therefore pain. This difficult problem has been addressed in the past with either an anteroposterior spinal osteotomy and fusion or a SmithPeterson osteotomy. By the very nature of these procedures, the spinal cord can be placed at risk secondary to the lengthening of the anterior spinal column. Pedicle subtraction osteotomy achieves a rebalanced spine without lengthening neural elements. Purpose: The purpose of this review is to report the clinical and radiographic outcome of patients who have undergone pedicle subtraction osteotomy in order to achieve significant correction of sagittal and coronal imbalance. Materials and methods: The clinical course and radiographic analysis of 27 consecutive patients who underwent pedicle subtraction osteotomy were evaluated. The clinical evaluation included operative time, blood loss, hospital stay, complications and the pre- and postoperative pain medi-
Proceedings of the NASS 16th Annual Meeting / The Spine Journal 2 (2002) 3S–44S cation use. This information was gathered from both clinic and hospital charts and by direct contact with the patients. The radiographic analysis compared preoperative sagittal and coronal balance with postoperative sagittal and coronal balance. In addition, the amount of correction obtained at the osteotomy site and the overall lumbar sagittal contour change from preand postoperative radiographs were evaluated. The coronal balance was measured from C7 to the middle of the sacrum on an AP film with a plum line. The overall sagittal balance was measured from the anterior/inferior edge of C7 to the posterior aspect of S1 again, with a plum line. The osteotomy correction was measured using the Cobb angle technique from the end plate immediately above and below the operative level. The degree of lumbar lordosis was measured from the inferior end plate of T12 to the superior end plate of S1. Results: Sixteen female and 11 male patients underwent pedicle subtraction osteotomy between 1996 and 2000. The average age was 49 years, with the mean number of previous spinal operations of three. Even in the multiply operated spine, pedicle fixation was obtained 100% of the time in the lumbar spine to aid in maintaining the appropriated sagittal contour. The average blood loss was 1,116 cc and the average operative time was 6 hours and 45 minutes, with a mean hospital stay of 6 days. The average preoperative coronal and sagittal imbalance were 4.38 cm and 12.22 cm, respectively. The postoperative correction on the immediate follow-up showed coronal and sagittal balance of 1.84 cm and 3.42 cm, respectively. This represents a 58% correction in the coronal plane and a 72% correction in the sagittal plane. This correction was maintained at the latest follow-up with only a .09 cm average loss of correction in the coronal plane and .04 cm average loss of correction in the sagittal plane. This loss of correction is well within measurement error and is considered to be negligible. The average follow-up examination was 15 months from the index procedure. The correction obtained through the osteotomy site was 31 degrees on average with an increase in lumbar lordosis from 28 degrees preoperatively to 49 degrees postoperatively. The overall satisfaction with surgery was quite high, even with nine patients having complications. There were no incidences of spinal cord injury or nerve root loss. There were four infections (one deep, three superficial), which resolved with the appropriate antibiotic course. There were four cases of pseudarthrosis requiring a second operation, all of which went on to a solid union. In evaluating the amount of pain medicines used pre- and postoperatively, 60% of patients went from narcotic use to only an anti-inflammatory agent or nothing for pain management. Seventeen percent of the patients still used an occasional narcotic pain pill to manage their back pain, but all patients had an overall decrease in the use of pain medicines. Conclusion: Pedicle subtraction osteotomy is a safe and effect treatment for patients who have flat back syndrome. It is the authors’ belief that pedicle subtraction osteotomy is a safer approach than the previously described methods of treating this problem. Pedicle subtraction osteotomy can be performed on patients who have had multiple spinal operations. This simple posterior procedure offers excellent radiographic and clinical improvements with limited complications. The role of measured resistance exercises in adolescent scoliosis Vert Mooney, MD, Allison Brigham, BS, San Diego, CA, USA Purpose: To document the effect of progressive strength training in torso rotation in individuals with adolescent scoliosis. Preliminary work at our center has demonstrated that all scoliotic adolescents had an asymmetry of rotation strength measured on specialized equipment, which isolates the torso rotation strength. In addition, surface electrode electromyograms had demonstrated inhibition of lumbar paraspinal muscles. The inhibition and strength corrected after several sessions of isolated progressive exercise training. Methods: Twenty-five adolescents (23 females, 2 males) with scoliosis ranging from 15 to 41 in their major curve were treated with a progressive resistive training program for torso rotation. They were treated twice a week until skeletal maturity or documented reduction of curve. None were braced during the period of treatment. Starting resistance was one third of body weight. Equal resistance was used for both left and right rotation, al-
15S
though initially rotation was weaker in one direction compared with the other. Once able to carry out 20 repetitions, the resistance was increased about 5%. Rotation range was increased as tolerated. Patients with surgical level of curves did not respond and were not followed. Results: Eighteen of 25 demonstrated curve reduction. Although there was some fluctuation, none of the rest had a persistent increase in curve. Pretraining average range was 28.2 13.2. Posttraining range was 23.0 14.1. The percentage improvement was 20% 23.3%. There was a 132.5% (61.4%) increase in dynamic strength. None went on to surgery or bracing. Discussion: Based on the demonstration of strength and asymmetry in rotation and inhibited lumbar extensor muscle activity, it is rational to place adolescents with scoliosis into a progressive resistance training program. In this small series, it offered notable benefit with documented control of curve progression. Parents were pleased that an active intervention was provided rather than “watch and wait” typical of presurgical adolescent scoliotic care. Lack of efficacy of exercise in previous studies may be because there was a lack of specific muscle training and measurement. No exercise program using equipment has previously been reported. Adolescent idiopathic scoliosis, bracing and the Hueter-Volkmann principle Frank P. Castro, MD, Amy Young, Richard T. Holt, MD, Mohammed E. Majd, MD, Louisville, KY, USA Purpose: Asymmetric chondrogenesis, in accordance with the HueterVolkmann principle, is frequently cited as a potential cause for adolescent idiopathic scoliosis (AIS). Brace treatment may reverse the abnormal forces across the apical vertebrae. The purpose of this investigation was to determine whether long-term brace treatment stimulated asymmetric chondrogenesis in the apical three vertebrae in patients with AIS. Three male and 38 female patients met the following inclusion criteria for the study: skeletal immaturity (Risser 0 or 1) at initial presentation, a major curve between 20 and 40 degrees, treatment consisting of a thoracolumbosacral orthosis, a minimum of 2 years of follow-up and documented skeletal maturity at final follow-up (Risser 5). Methods: Cobb angles and concave-to-convex height ratios of the apical three vertebral bodies were measured when bracing was indicated, in the brace, and after skeletal maturity. Measurements were compared by a repeated-measures analysis of variance statistic. Results: Cobb measurements improved 50% (p.0001) with the application of a brace. Immediate radiographic improvements were also measured in the cephalad (p.0027) and caudal (p.0004) apical height ratios when the brace was initially applied. On average, Cobb measurements increased six degrees after an average of 41 months of follow-up (p.001). Vertebral body remodeling by asymmetric chondrogenesis, as evidenced by changes in the concave-to-convex height ratios, were not appreciated. Conclusion: Application of a brace to patients with AIS resulted in immediate radiographic improvements in the Cobb measurements and concaveto-convex height ratios. Structural changes in vertebral body shape resulting from asymmetric chondrogenesis were not appreciated. Thus, the HueterVolkmann principle appears not to be applicable in patients with AIS with curves between 20 and 40 Cobb angle degrees treated with a brace. The Million Visual Analogue Scale: its utility for predicting outcomes after tertiary rehabilitation Tom Mayer, MD, Timothy Proctor, PhD, Robert J. Gatchel, PhD, Dallas, TX, USA Introduction: The Million Visual Analogue Scale (MVAS) [1] is a 15item visual analog measure of spinal pain disability. This instrument produces a total functional disability score ranging from 0 to 150. Like other “disability inventories,” such as the Oswestry and the Roland-Morris, the MVAS differs from a “pain inventory” in that the focus is on disability and function, as opposed to self-reported pain. The MVAS may be the strongest functional rating scale, because all questions relate to the patient’s ability to perform activities of daily living. In addition, this instrument has the advantage of a visual analog format, which is typically considered