Management Of Spastic Equinovarus Foot in Children with Cerebral Palsy: An Evaluation of Anatomical Landmarks for Selective Nerve Blocks of the Tibial Nerve Motor Branches

Abstract

Objective: To define the anatomical landmarks of tibial motor nerve branches for selective motor nerve blocks of the gastrocnemii, soleus and tibialis posterior muscles in the management of spastic equinovarus foot. Design: Observational study. Patients: Twenty-four children with cerebral palsy with spastic equinovarus foot. Methods: Considering the affected leg length, motor nerve branches to the gastrocnemii, soleus and tibialis posterior muscles were tracked using ultrasonography, and located in the space (vertical, horizontal, deep) according to the position of fibular head (proximal/distal) and a virtual line from the middle of popliteal fossa to the Achilles tendon insertion (medial/lateral). Results: Location of motor branches was defined as percentage of the affected leg length. Mean coordinates were: for the gastrocnemius medialis 2.5 ± 1.2% vertical (proximal), 1.0 ± 0.7% horizontal (medial), 1.5 ± 0.4% deep; for the gastrocnemius lateralis 2.3 ± 1.4% vertical (proximal), 1.1 ± 0.9% horizontal (lateral), 1.6 ± 0.4% deep; for the soleus 2.1 ± 0.9% vertical (distal), 0.9 ± 0.7% horizontal (lateral), 2.2 ± 0.6% deep; for the tibialis posterior 2.6 ± 1.2% vertical (distal), 1.3 ± 1.1% horizontal (lateral), 3.0 ± 0.7% deep. Conclusion: These findings may help the identification of tibial motor nerve branches to perform selective nerve blocks in patients with cerebral palsy with spastic equinovarus foot. LAY ABSTRACT This observational study was performed on a sample of 24 children with cerebral palsy in order to identify the motor nerve branches to the main calf muscles for assisting the management of spastic foot. All patients were evaluated with ultrasonography. The nerve branches to the gastrocnemii, soleus and tibialis posterior muscles were located in space (vertical, horizontal, deep), based on the position of the fibular head (proximal/distal) and a posterior line in the middle of the leg (medial/lateral). Location of motor branches was defined as percentage of the affected leg length. The mean coordinates for the gastrocnemius medialis motor branch were 2.5% proximal, 1.0% medial, 1.5% deep; for the gastrocnemius lateralis: 2.3% proximal, 1.1% lateral, 1.6% deep; for the soleus: 2.1% distal, 0.9% lateral, 2.2% deep; for the tibialis posterior: 2.6% distal, 1.3% lateral, 3.0% deep. These findings may help the management of spastic foot in children with cerebral palsy.

Keywords

• equinus deformity
• muscle spasticity
• nerve block
• ultrasonography