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Changes in dynamic electromyographic-recordings following repetitive botulinum toxin treatment in dynamic equinus gait due to cerebral palsy
Abstracts
73
(HUGH WILLIAMSON'S GAIT ANALYSIS LABORATORY, ROYAL CHILDREN'S HOSPITAL, FLEMINGTON RD, PARKVILLE 3052, VICTORIA, AUSTRALIA)
improvements are associated with changes in electromyographic(EMG)-pattem of walking a preliminary analysis of pre- and post-injection instrumental gait analysis of 9 CP children with dynamic equinus gait pattern was performed.
Introduction: Ambulant children with cerebral palsy (CP) often have a gait pattern that is associated with increased oxygen consumption during walking ~'3 Single Event Multilevel Surgery (SEMLS) aims to correct deformities of the lower limbs in ambulant children with CP by a combination of tendon lengthening, tendon transfers and demtational osteotomies 2. The objective is to study the effects of SEMLS on 02 cost during walking in spastic diplegic children with lower limb deformities and gait disturbance.
METHODOLOGY Nine children (5 diplegic, 4 hemiplegic gait,mean age 8.5 [7-11] years) with CP were included into the ongoing study. No child had previous surgery, or relevant concomitant diseases. Children got injections into the gastrecnemius muscles (5 units Botox® per kg body weight per leg distributed between the lateral and medial head of the gastrocnemius muscle). Baseline and follow-up assessments (4 weeks lbllowing first injection and 3 months fbllowing 2. injection) included clinical measures (modified Ashworth scale, passive and active range of motion (ROM) of the ankle tested in supine position) and instrumental gait analysis with registration of dynamic EMG of the tibialis anterior and gastrocnemius muscles (Telemyo®, Vierma,Austria + MyoResearch 97®, Gait Protocol software. Nuraxon, US, Arizona). EMG's were analysed semiquantitatively pre- and post-injection by comparing the amplitude of rectified EMG activity normalised to I00% gait cycle. At tbllow-up visits side effects were evaluated and subjective response was rated by tlre parents or physiotherapists using a rating scale (-3 = marked worsening, -2 = moderate worsening, -1 = mild worsening, 0 = no change, +1 = mild improvement, +2 = moderate improvement, +3 = marked improvement).
Methodology: A prospective two-year clinical trial with a consecutively recruited cohort of children with spastic diplegia who presented for lower limb surgery to correct deformity and to improve gait. Oz cost was assessed using the Cosmed K4 during a 10-minute walk on an oval tmek at self selected speed using usual aids and erthotics. Patients were assessed in the month prior to surgery, at three monthly intervals for the first year and at 24 months following a standardized protocol. One-year data are available. Paired t-tests were used for the statistical analysis of the mean change of O_,cost within individuals before and after surgery.
Definitions: At 12 months patients were considered to have: 1) improved: if the O2 cost was either decreased by more than 20% provided the speed had not decreased by more than 20% compared to baseline; or if the O2 cost was unchanged, but the speed had increased by more than 20%. 2) deteriorated: if the O~ cost was either increased by more than 20% provided the speed had not increased by more than 20% compared to baseline; or if the O2 cost was unchanged, but the speed had decreased by more than 20%. 3) not changed: if the 02 cost was neither increased nor decreased by more than 20% provided the speed had not increased or decreased by more than 20% compared to baseline.
Results: We found a sharp increase in 0 2 cost at three months after surgery with a corresponding reduction in speed and functional ability. O2 cost (mls %/m/kg) was significantly increased three months after surgery (pre-operative: 0.69 mls/mlkg; 3 months: 1.6 mls/m/kg; p<0.05) At 12 months after surgery and rehabilitation we were able to divide our patient population into three distinct groups on the basis of energy data. Outcome at 12 months improved deteriorated
unchanged
n=21 11 6 , ]4
Associations Severe crouch gait age - severity of deformities surgical complications ? suboptimal rehabilitation
I) Out of the l 1 patients that had improved, 4 bad improved in both O, cost as well as speed, 6 patients had improved in 02 cost with an unchanged speed and 1 patient had an improved speed with unchanged % cost. 2) Out of the six patients that had deteriorated, 5 had an increased O~ cost as well as a decrease in speed. One patient had an increase in the O2 cost with no change in speed. 3) Four patients had no significant change in either Oz neither cost nor speed compared to baseline.
Conclusions: This is the first study to characterize the rehabilitation period after multiple lower extremity orthopedic procedures using serial measurements of O2 cost of walking. The major increase in 0_~ cost at three months is of great concern because some children are at risk of remaining at an impaired functional level if their rehabilitation is suboptimal. Recognition of subgroups of patients who have decreased O2 cost of walking compared to those who have unchanged 02 cost or increased 02 cost should help in patient selection for multiple lower extremity orthopedic procedures and in planing rehabilitation programs.
References:
1 Nene AV, et at., J Bone Joint Surg [Br], 75-B: 488-494, 1993. 2 Gage JR, et al., J Paediatr Orthop, 4(6): 715-725, 1984. 3 Duffy CM, et al., Dev Med Child Neurol, 38: 238-243, 1996.
Session 9 Botulinum Toxin CHANGES IN DYNAMIC ELECTROMYOGRAPHIC-RECORDINGS FOLLOWING REPETITIVE BOTULINUM TOXIN TREATMENT IN DYNAMIC EQUINUS GAIT DUE TO CEREBRAL PALSY A. Baldauf, J. Wissul, J. Mtlller, S.C. Ung, M. Sojer, B. St6ckl*, B. Frischhut*, H. HaberfelIner ÷. J.P. Ndayisaba. W. Poewe Departments of Neurology, Orthopedics*, Pediatrics t, University of Innsbruck, Austria
INTRODUCTION Botulinum toxin (Btx) has been used in the management of children with dystonia (2) and cerebral palsy (2,4,5). Btx injections in adults with spasticity and children with cerebral palsy (CP) showed a dose related decrease in muscle tone and increased joint mobility following injections (3,5). To adress the question whether Btx related
RESULTS Subjective response rated by the parents or physiotherapist revealed in 8 of 9 children mild (n=5) and moderate (n=3) improvements after 1.injection and in 7 of 9 children mild (n=5) and moderate(n=2) improvements after 2.injection. Mild worsening was reported in one child with slight increase of internal rotation of the hip. Side effects (hematoma and pain on injection site) were reported in 2 children, otherwise no local or generalised side effects were reported. At follow-up visit (1. follow-up: mean 33.1 [26-42] days and 2. follow-up: mean 83.9 [77-91] days after 2. injection) a significant increase in ankle ROM documented improvement in passive and active joint mobility (p<0.05, each). Modified Ashworth scores improved not significantly following treatment (see table 1). Semiquantitative analysis of EMG recordings revealed at 1. follow-up a reduction of prolonged tibialis anterior activity during stance phase (8 of 14 investigated legs) and an increase in EMG activity during swing phase (8 of 14 investigated legs). There was only a mild reduction in the amplitude of the rectified EMG activity of the gastrocnemius muscle (9 of 14 investigated legs) during stance phase following I.injection into gastrocnemius muscle. 12 weeks following second injection a reduction of prolonged activity during stance phase (5 of 13 investigated legs) and an increase in EMG activity of tibial anterior muscle daring swing phase (3 of l 3 investigated legs) was still present. The gastrocnemius EMG activity still showed a mild decrease in 8 of 13 investigated legs during stance phase. DISCUSSION Clinical investigation 4 weeks after the first and 12 weeks following second Btx treatment showed significant improvements in active and passive ankle ROM, which represent a prolonged increase in ankle mobility. Berger etal. (1) found two major disturbances in leg muscle EMG activation during gait cycle in children with CP: 1. an overall reduction in EMG activity and 2. a cocontraction pattern of antagonistic muscles (gastrocnemius and tibial anterior muscle) durin-_ stance phase. This study showed Btx induced changes in EMG-pattern following injec',ion with decreased EMG activity of tibial anterior muscle during stance and increased activity during swing phase representing decreased cocontraction patterns during gait cycle. There are two hypothesis which might explain this observation: 1. equinus reduction with Btx injections into the gastroenemius muscles decreases instability of the subtalar joint which leads to a decrease in cocontraetion of tibialis anterior muscle (4), 2. mediated by denervation of intrafasal muscle fibres an alteration o f muscle spindle information induced a central reorganlsation of reciprocal inhibition. Up to now it is not clear which hypothesis is sufficient to explain the underlying mechanism of Btx induced changes in dynamic EMG in CP. Table 1. Baseline Modified ankle Ashworth Scale knee ROM ankle joint
passive active
4 weeks post I .injection 2,57t [0-3] 0,857 [0-2] 58,2 ° [40-70] 26,1 ° [0-401 *p<0,05
12 weeks post 2.injection 2 2,428 [0-3] [0-3] 0,571 0,5 [0-1] [0-2] 66,1 °* 67,8 °* [40-75] [65-80] 35,7 °* 39,6 °* [10-75] [0-75]
REFERENCES I. Berger W, Quintem J, Dietz V (1982) Pathophysiology of gait in children with cerebral palsy. Electroenc Clin NeurophysioI 53:538-548. 2. Heinen F, Wissel J, Philipsen A,et a1.(1997) Intervantional Neuropedriafias:Treatment of Dystonic and Spastic Muscular Hyperactivity with BtxA. Neuropedriatics 28:307-313 3. Simpson DM, Alexander DN, O'Brin CF, et al. (1996) Botutinum toxin type A in the treatment of upper extremity spasticity: A randomized, double-blind, placebo-anntrolled trail. Neurology 46:1306-1310. Sutherland DH, Kaufman KR, Wyatt MP, Chambers FIG (1996) Injection of botulinum A toxin into gastroanemius muscle of patients with cerebral palsy: a 3-dimentional motion analysis study. Gait & Posture 4:269-279. Wissel J, Heinen F., Sehenkel A, et al. (1999) Botulinum Toxin A in the Management of Spastic Gait Disorders in Children and Young Adults with Cerebral Palsy: A Randomized, Double-blind Study of "'High-dose" versus "Low-dose" Treatment. Neuropediatrics in press.
73
(HUGH WILLIAMSON'S GAIT ANALYSIS LABORATORY, ROYAL CHILDREN'S HOSPITAL, FLEMINGTON RD, PARKVILLE 3052, VICTORIA, AUSTRALIA)
improvements are associated with changes in electromyographic(EMG)-pattem of walking a preliminary analysis of pre- and post-injection instrumental gait analysis of 9 CP children with dynamic equinus gait pattern was performed.
Introduction: Ambulant children with cerebral palsy (CP) often have a gait pattern that is associated with increased oxygen consumption during walking ~'3 Single Event Multilevel Surgery (SEMLS) aims to correct deformities of the lower limbs in ambulant children with CP by a combination of tendon lengthening, tendon transfers and demtational osteotomies 2. The objective is to study the effects of SEMLS on 02 cost during walking in spastic diplegic children with lower limb deformities and gait disturbance.
METHODOLOGY Nine children (5 diplegic, 4 hemiplegic gait,mean age 8.5 [7-11] years) with CP were included into the ongoing study. No child had previous surgery, or relevant concomitant diseases. Children got injections into the gastrecnemius muscles (5 units Botox® per kg body weight per leg distributed between the lateral and medial head of the gastrocnemius muscle). Baseline and follow-up assessments (4 weeks lbllowing first injection and 3 months fbllowing 2. injection) included clinical measures (modified Ashworth scale, passive and active range of motion (ROM) of the ankle tested in supine position) and instrumental gait analysis with registration of dynamic EMG of the tibialis anterior and gastrocnemius muscles (Telemyo®, Vierma,Austria + MyoResearch 97®, Gait Protocol software. Nuraxon, US, Arizona). EMG's were analysed semiquantitatively pre- and post-injection by comparing the amplitude of rectified EMG activity normalised to I00% gait cycle. At tbllow-up visits side effects were evaluated and subjective response was rated by tlre parents or physiotherapists using a rating scale (-3 = marked worsening, -2 = moderate worsening, -1 = mild worsening, 0 = no change, +1 = mild improvement, +2 = moderate improvement, +3 = marked improvement).
Methodology: A prospective two-year clinical trial with a consecutively recruited cohort of children with spastic diplegia who presented for lower limb surgery to correct deformity and to improve gait. Oz cost was assessed using the Cosmed K4 during a 10-minute walk on an oval tmek at self selected speed using usual aids and erthotics. Patients were assessed in the month prior to surgery, at three monthly intervals for the first year and at 24 months following a standardized protocol. One-year data are available. Paired t-tests were used for the statistical analysis of the mean change of O_,cost within individuals before and after surgery.
Definitions: At 12 months patients were considered to have: 1) improved: if the O2 cost was either decreased by more than 20% provided the speed had not decreased by more than 20% compared to baseline; or if the O2 cost was unchanged, but the speed had increased by more than 20%. 2) deteriorated: if the O~ cost was either increased by more than 20% provided the speed had not increased by more than 20% compared to baseline; or if the O2 cost was unchanged, but the speed had decreased by more than 20%. 3) not changed: if the 02 cost was neither increased nor decreased by more than 20% provided the speed had not increased or decreased by more than 20% compared to baseline.
Results: We found a sharp increase in 0 2 cost at three months after surgery with a corresponding reduction in speed and functional ability. O2 cost (mls %/m/kg) was significantly increased three months after surgery (pre-operative: 0.69 mls/mlkg; 3 months: 1.6 mls/m/kg; p<0.05) At 12 months after surgery and rehabilitation we were able to divide our patient population into three distinct groups on the basis of energy data. Outcome at 12 months improved deteriorated
unchanged
n=21 11 6 , ]4
Associations Severe crouch gait age - severity of deformities surgical complications ? suboptimal rehabilitation
I) Out of the l 1 patients that had improved, 4 bad improved in both O, cost as well as speed, 6 patients had improved in 02 cost with an unchanged speed and 1 patient had an improved speed with unchanged % cost. 2) Out of the six patients that had deteriorated, 5 had an increased O~ cost as well as a decrease in speed. One patient had an increase in the O2 cost with no change in speed. 3) Four patients had no significant change in either Oz neither cost nor speed compared to baseline.
Conclusions: This is the first study to characterize the rehabilitation period after multiple lower extremity orthopedic procedures using serial measurements of O2 cost of walking. The major increase in 0_~ cost at three months is of great concern because some children are at risk of remaining at an impaired functional level if their rehabilitation is suboptimal. Recognition of subgroups of patients who have decreased O2 cost of walking compared to those who have unchanged 02 cost or increased 02 cost should help in patient selection for multiple lower extremity orthopedic procedures and in planing rehabilitation programs.
References:
1 Nene AV, et at., J Bone Joint Surg [Br], 75-B: 488-494, 1993. 2 Gage JR, et al., J Paediatr Orthop, 4(6): 715-725, 1984. 3 Duffy CM, et al., Dev Med Child Neurol, 38: 238-243, 1996.
Session 9 Botulinum Toxin CHANGES IN DYNAMIC ELECTROMYOGRAPHIC-RECORDINGS FOLLOWING REPETITIVE BOTULINUM TOXIN TREATMENT IN DYNAMIC EQUINUS GAIT DUE TO CEREBRAL PALSY A. Baldauf, J. Wissul, J. Mtlller, S.C. Ung, M. Sojer, B. St6ckl*, B. Frischhut*, H. HaberfelIner ÷. J.P. Ndayisaba. W. Poewe Departments of Neurology, Orthopedics*, Pediatrics t, University of Innsbruck, Austria
INTRODUCTION Botulinum toxin (Btx) has been used in the management of children with dystonia (2) and cerebral palsy (2,4,5). Btx injections in adults with spasticity and children with cerebral palsy (CP) showed a dose related decrease in muscle tone and increased joint mobility following injections (3,5). To adress the question whether Btx related
RESULTS Subjective response rated by the parents or physiotherapist revealed in 8 of 9 children mild (n=5) and moderate (n=3) improvements after 1.injection and in 7 of 9 children mild (n=5) and moderate(n=2) improvements after 2.injection. Mild worsening was reported in one child with slight increase of internal rotation of the hip. Side effects (hematoma and pain on injection site) were reported in 2 children, otherwise no local or generalised side effects were reported. At follow-up visit (1. follow-up: mean 33.1 [26-42] days and 2. follow-up: mean 83.9 [77-91] days after 2. injection) a significant increase in ankle ROM documented improvement in passive and active joint mobility (p<0.05, each). Modified Ashworth scores improved not significantly following treatment (see table 1). Semiquantitative analysis of EMG recordings revealed at 1. follow-up a reduction of prolonged tibialis anterior activity during stance phase (8 of 14 investigated legs) and an increase in EMG activity during swing phase (8 of 14 investigated legs). There was only a mild reduction in the amplitude of the rectified EMG activity of the gastrocnemius muscle (9 of 14 investigated legs) during stance phase following I.injection into gastrocnemius muscle. 12 weeks following second injection a reduction of prolonged activity during stance phase (5 of 13 investigated legs) and an increase in EMG activity of tibial anterior muscle daring swing phase (3 of l 3 investigated legs) was still present. The gastrocnemius EMG activity still showed a mild decrease in 8 of 13 investigated legs during stance phase. DISCUSSION Clinical investigation 4 weeks after the first and 12 weeks following second Btx treatment showed significant improvements in active and passive ankle ROM, which represent a prolonged increase in ankle mobility. Berger etal. (1) found two major disturbances in leg muscle EMG activation during gait cycle in children with CP: 1. an overall reduction in EMG activity and 2. a cocontraction pattern of antagonistic muscles (gastrocnemius and tibial anterior muscle) durin-_ stance phase. This study showed Btx induced changes in EMG-pattern following injec',ion with decreased EMG activity of tibial anterior muscle during stance and increased activity during swing phase representing decreased cocontraction patterns during gait cycle. There are two hypothesis which might explain this observation: 1. equinus reduction with Btx injections into the gastroenemius muscles decreases instability of the subtalar joint which leads to a decrease in cocontraetion of tibialis anterior muscle (4), 2. mediated by denervation of intrafasal muscle fibres an alteration o f muscle spindle information induced a central reorganlsation of reciprocal inhibition. Up to now it is not clear which hypothesis is sufficient to explain the underlying mechanism of Btx induced changes in dynamic EMG in CP. Table 1. Baseline Modified ankle Ashworth Scale knee ROM ankle joint
passive active
4 weeks post I .injection 2,57t [0-3] 0,857 [0-2] 58,2 ° [40-70] 26,1 ° [0-401 *p<0,05
12 weeks post 2.injection 2 2,428 [0-3] [0-3] 0,571 0,5 [0-1] [0-2] 66,1 °* 67,8 °* [40-75] [65-80] 35,7 °* 39,6 °* [10-75] [0-75]
REFERENCES I. Berger W, Quintem J, Dietz V (1982) Pathophysiology of gait in children with cerebral palsy. Electroenc Clin NeurophysioI 53:538-548. 2. Heinen F, Wissel J, Philipsen A,et a1.(1997) Intervantional Neuropedriafias:Treatment of Dystonic and Spastic Muscular Hyperactivity with BtxA. Neuropedriatics 28:307-313 3. Simpson DM, Alexander DN, O'Brin CF, et al. (1996) Botutinum toxin type A in the treatment of upper extremity spasticity: A randomized, double-blind, placebo-anntrolled trail. Neurology 46:1306-1310. Sutherland DH, Kaufman KR, Wyatt MP, Chambers FIG (1996) Injection of botulinum A toxin into gastroanemius muscle of patients with cerebral palsy: a 3-dimentional motion analysis study. Gait & Posture 4:269-279. Wissel J, Heinen F., Sehenkel A, et al. (1999) Botulinum Toxin A in the Management of Spastic Gait Disorders in Children and Young Adults with Cerebral Palsy: A Randomized, Double-blind Study of "'High-dose" versus "Low-dose" Treatment. Neuropediatrics in press.