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Length of the gastrosoleus complex and dynamic EMG of peroneus longus and gastrocnemius medialis in hemiplegic children with equinovarus: The hypothesis of the spastic cocontraction
ESMAC Abstracts 2015 / Gait & Posture 42S (2015) S1–S101
Fig. 2. Comparison of frequency spectra between the three study groups of the m. gastrocnemius medialis, m. tibialis anterior, m. rectus femoris, and medial hamstrings.
Discussion: In both CP groups muscle function was impaired as muscle activities and IMNF were increased. The wavelet parameters for the DI-CP and TE-CP groups were not different, indicating that the structure and neuro-muscular innervation may be similar. Muscle biopsies may confirm these speculations. References [1] Lauer. Gait Posture 2005:25. [2] Tscharner VJ. Electromyogr Kinesiol 2000:10. [3] Baker. Gait Posture 2009:30.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.023
Session OS03 Muscle Function and Imaging Length of the gastrosoleus complex and dynamic EMG of peroneus longus and gastrocnemius medialis in hemiplegic children with equinovarus: The hypothesis of the spastic cocontraction C. Boulay 1,∗ , M. Jacquemier 1 , E. Castanier 1 , G. Authier 1 , P. Vincent 1 , B. Chabrol 2 , J.-L. Jouve 1 , E. Viehweger 1 1 Service Chirurgie Orthopédique Pédiatrique, CHU Timone Enfants, Marseille, France 2 Service de Neurologie Pédiatrique, CHU Timone Enfants, Marseille, France
Research question: In the hemiparetic child with cerebral palsy (CP), before the bone deformities are set into place, abnormal electromyography (EMG) for the gastrocnemius medialis (GM) are likely to trigger equinus: during the swing phase (SW) prior to initial contact (IC), GM EMG is premature [1]. In equinovarus, premature GM and tibialis posterior (TP) EMG has been observed [1]. As concerns equinovarus in a CP child, Perry [1] took note of premature EMG during the SW of the peroneus longus (PL) and had not studied a pathophysiological explanation; moreover, it was deemed paradoxical due to the action of the equinovalgus deformity of the PL in CP [2]. Introduction: That is why the objective was to quantify the PL and GM EMG in hemiparetic children with equinovarus. We wished to determine whether or not the synergic action, as a spastic co-contraction, of PL and GM should be put forward as a hypothesis. The goal was to analyze the onset of EMG in the GM and PL. Materials and methods: Fifteen hemiparetic children (age 5 ± 1.5 yrs) were clinically assessed for functional muscle length XV1 of gastrosoleus complex (GSC) [3] and monitored for GM and PL EMG during gait with equinovarus at IC. The latter was normalized in terms of gait cycle (0–100%) and detected through
S9
semi-automatic selection with activation threshold set at 20 V [2]. The premature onset of EMG was normalised as a SW percentage prior to IC of the following stance (ST). A paired T-test compared the activation onset of the PL versus the GM muscles. Results: XV1 of GSC was 104 ± 7◦ on the paretic side vs 108 ± 4◦ on the non-paretic side (p < 0.05). On the healthy limb, activity onset of GM (+14.55%) and PL (+19.2%) occurred only during ST. In equinovarus, activation of GM (−5.2%) and PL (−6.1%) occurred during SW and was premature. For each muscle, comparison between the healthy and the hemiplegic side was highly significant (p < 0.001). Discussion: GSC was significantly shorter, but without contracture, in the paretic side which probably contributes to dynamic equinus by the facilitation of the muscular overactivity [4]. Premature PL and GM EMG preceding IC corresponds not to a disorder secondary to imbalance but rather, more probably, to motor command dysfunction; especially, a spastic cocontraction defined as a misdirected supraspinal command to the antagonist muscle (GM and PL) during the agonist contraction in SW [4]. While the PL consequently contributes to equinus deformity, its possible role in varus genesis is less evident. EMG study needs to be completed by comparing PL and TP strength while taking foot bone morphology into full account. References [1] Perry J. Gait analysis: normal and pathological function. New York: McGraw Hill; 1992. [2] Boulay C. Dynamic equinus with hindfoot valgus in children with hemiplegia. Gait Posture 2012;36:108–12. [3] Gracies JM. Reliability of the tardieu scale for assessing spasticity in children with cerebral Palsy. Arch Phys Med Rehabil 2010;91(3): 421–8. [4] Gracies JM. Pathophysiology of spastic paresis. Emergence of muscle overactivity. Muscle Nerve 2005;31(5):552–71.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.024
Session OS03 Muscle Function and Imaging Reliability and validity of 3D freehand ultrasound F. Cenni 1 , D. Monari 1,∗ , E. Aertbeliën 1 , L. Scheys 2 , K. Desloovere 3 , H. Bruyninckx 1 1
KU Leuven, Department of Mechanical Engineering, Leuven, Belgium 2 University Hospital Leuven, Department of Orthopaedics, Pellenberg, Belgium 3 University Hospital Leuven, Clinical Motion Analysis Laboratory, Pellenberg, Belgium Research question: Is 3D ultrasound a reliable and valid method for estimating lengths and volumes? Introduction: 3D freehand ultrasound (3DUS) is a technique that enhances a typical 2D US device into a platform able to reconstruct 3D anatomical segments. To perform this technique, US is combined with a motion analysis system. The feasibility [1,2] and validity [3] of 3DUS has previously been shown. However, a comprehensive study providing both the reliability and validity of volume and length is lacking. Therefore, by using 3DUS, the aim of this study is to comprehensively assess the reliability and validity of volume and length on known objects, in a water tank. The hypothesis is that the present method will be suitable for translation to clinical practice. Materials and methods: Ten water-filled balloons and a grid of 6 crossed-wires were used. A stack of images using 3DUS (Telemed, Lithuania) was acquired with a linear probe (59 mm), at 30 Hz. To
Fig. 2. Comparison of frequency spectra between the three study groups of the m. gastrocnemius medialis, m. tibialis anterior, m. rectus femoris, and medial hamstrings.
Discussion: In both CP groups muscle function was impaired as muscle activities and IMNF were increased. The wavelet parameters for the DI-CP and TE-CP groups were not different, indicating that the structure and neuro-muscular innervation may be similar. Muscle biopsies may confirm these speculations. References [1] Lauer. Gait Posture 2005:25. [2] Tscharner VJ. Electromyogr Kinesiol 2000:10. [3] Baker. Gait Posture 2009:30.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.023
Session OS03 Muscle Function and Imaging Length of the gastrosoleus complex and dynamic EMG of peroneus longus and gastrocnemius medialis in hemiplegic children with equinovarus: The hypothesis of the spastic cocontraction C. Boulay 1,∗ , M. Jacquemier 1 , E. Castanier 1 , G. Authier 1 , P. Vincent 1 , B. Chabrol 2 , J.-L. Jouve 1 , E. Viehweger 1 1 Service Chirurgie Orthopédique Pédiatrique, CHU Timone Enfants, Marseille, France 2 Service de Neurologie Pédiatrique, CHU Timone Enfants, Marseille, France
Research question: In the hemiparetic child with cerebral palsy (CP), before the bone deformities are set into place, abnormal electromyography (EMG) for the gastrocnemius medialis (GM) are likely to trigger equinus: during the swing phase (SW) prior to initial contact (IC), GM EMG is premature [1]. In equinovarus, premature GM and tibialis posterior (TP) EMG has been observed [1]. As concerns equinovarus in a CP child, Perry [1] took note of premature EMG during the SW of the peroneus longus (PL) and had not studied a pathophysiological explanation; moreover, it was deemed paradoxical due to the action of the equinovalgus deformity of the PL in CP [2]. Introduction: That is why the objective was to quantify the PL and GM EMG in hemiparetic children with equinovarus. We wished to determine whether or not the synergic action, as a spastic co-contraction, of PL and GM should be put forward as a hypothesis. The goal was to analyze the onset of EMG in the GM and PL. Materials and methods: Fifteen hemiparetic children (age 5 ± 1.5 yrs) were clinically assessed for functional muscle length XV1 of gastrosoleus complex (GSC) [3] and monitored for GM and PL EMG during gait with equinovarus at IC. The latter was normalized in terms of gait cycle (0–100%) and detected through
S9
semi-automatic selection with activation threshold set at 20 V [2]. The premature onset of EMG was normalised as a SW percentage prior to IC of the following stance (ST). A paired T-test compared the activation onset of the PL versus the GM muscles. Results: XV1 of GSC was 104 ± 7◦ on the paretic side vs 108 ± 4◦ on the non-paretic side (p < 0.05). On the healthy limb, activity onset of GM (+14.55%) and PL (+19.2%) occurred only during ST. In equinovarus, activation of GM (−5.2%) and PL (−6.1%) occurred during SW and was premature. For each muscle, comparison between the healthy and the hemiplegic side was highly significant (p < 0.001). Discussion: GSC was significantly shorter, but without contracture, in the paretic side which probably contributes to dynamic equinus by the facilitation of the muscular overactivity [4]. Premature PL and GM EMG preceding IC corresponds not to a disorder secondary to imbalance but rather, more probably, to motor command dysfunction; especially, a spastic cocontraction defined as a misdirected supraspinal command to the antagonist muscle (GM and PL) during the agonist contraction in SW [4]. While the PL consequently contributes to equinus deformity, its possible role in varus genesis is less evident. EMG study needs to be completed by comparing PL and TP strength while taking foot bone morphology into full account. References [1] Perry J. Gait analysis: normal and pathological function. New York: McGraw Hill; 1992. [2] Boulay C. Dynamic equinus with hindfoot valgus in children with hemiplegia. Gait Posture 2012;36:108–12. [3] Gracies JM. Reliability of the tardieu scale for assessing spasticity in children with cerebral Palsy. Arch Phys Med Rehabil 2010;91(3): 421–8. [4] Gracies JM. Pathophysiology of spastic paresis. Emergence of muscle overactivity. Muscle Nerve 2005;31(5):552–71.
http://dx.doi.org/10.1016/j.gaitpost.2015.06.024
Session OS03 Muscle Function and Imaging Reliability and validity of 3D freehand ultrasound F. Cenni 1 , D. Monari 1,∗ , E. Aertbeliën 1 , L. Scheys 2 , K. Desloovere 3 , H. Bruyninckx 1 1
KU Leuven, Department of Mechanical Engineering, Leuven, Belgium 2 University Hospital Leuven, Department of Orthopaedics, Pellenberg, Belgium 3 University Hospital Leuven, Clinical Motion Analysis Laboratory, Pellenberg, Belgium Research question: Is 3D ultrasound a reliable and valid method for estimating lengths and volumes? Introduction: 3D freehand ultrasound (3DUS) is a technique that enhances a typical 2D US device into a platform able to reconstruct 3D anatomical segments. To perform this technique, US is combined with a motion analysis system. The feasibility [1,2] and validity [3] of 3DUS has previously been shown. However, a comprehensive study providing both the reliability and validity of volume and length is lacking. Therefore, by using 3DUS, the aim of this study is to comprehensively assess the reliability and validity of volume and length on known objects, in a water tank. The hypothesis is that the present method will be suitable for translation to clinical practice. Materials and methods: Ten water-filled balloons and a grid of 6 crossed-wires were used. A stack of images using 3DUS (Telemed, Lithuania) was acquired with a linear probe (59 mm), at 30 Hz. To