Lidocaine hyperselective motor blocks of the triceps surae nerves: role of the soleus versus gastrocnemius on triceps spasticity and predictive value of the soleus motor block on the result of selective tibial neurotomy.

Objectives: This prospective study was designed to evaluate the clinical and gait parameter changes induced by two types of hyperselective motor blocks of the triceps surae nerves (superior soleus and gastrocnemius nerves) and their ability to predict the results of selective tibial neurotomy.

Design: Seven adult patients (four males and three females, mean age of 41 yrs old) with spastic foot were included in this study. Clinical (equinus foot score, ankle range of motion, spasticity, pain, and comfort wearing shoes), and gait analysis (kinematic and electromyographic parameters) assessment were performed before and after each motor block (superior soleus nerve and gastrocnemius nerve) and 1 mo after selective tibial neurotomy.

Results: The superior soleus nerve block was effective on clinical parameters (triceps surae stretch reflex scores decreased from 2.57 to 0.9, and mean walking time decreased from 44 to 32.1 secs) and on kinematics parameters (the total duration of the gait cycle was decreased because of a reduction of the R3 and swing phases). The same results are observed after soleus neurotomy.

Conclusion: This work confirms the practical value of selective superior soleus nerve motor block and that this block provides a useful prediction of the effect of selective soleus neurotomy. It constitutes an additional argument in favor of the predominant role of the soleus in spastic foot.