Diagnostic nerve block in prediction of outcome of botulinum toxin treatment for spastic equinovarus foot after stroke: A retrospective observational study

Abstract

This study reviewed data from 50 chronic stroke patients with spastic equinovarus foot in order to compare the outcome of tibial nerve (main trunk and motor branches) diagnostic block (which temporarily relieves focal muscle overactivity, allowing assessment of the contribution of different muscles) with that of subsequent botulinum toxin injected into the same muscles as were targeted by the nerve block. Outcome measures were passive motility of the affected ankle and overactivity of the calf muscles. All patients were evaluated before and after the nerve block, and 4 weeks after the botulinum toxin injection. Significant improvements were found both after the nerve block and after botulinum toxin injection in comparison with the baseline condition; however, the improvements observed after nerve block were significantly greater. These results confirm that diagnostic nerve block is a useful screening tool for use before botulinum toxin treat ment, although less improvement occurred after botulinum toxin injection compared with after nerve block. Objective: To evaluate the role of diagnostic nerve block in predicting the outcome of subsequent botulinum toxin type A treatment for spastic equinovarus foot due to chronic stroke. Design: Retrospective observational study. Patients: Fifty chronic stroke patients with spastic equinovarus foot. Methods: Each patient was given diagnostic tibial nerve block (lidocaine 2% perineural injection) assessment followed by botulinum toxin type A inoculation into the same muscles as had been targeted by the nerve block. All patients were evaluated before diagnostic nerve block, after the nerve block, and 4 weeks after botulinum toxin injection. Outcomes were ankle dorsiflexion passive range of motion of the affected side, and calf muscle spasticity, measured with the modified Ashworth scale and the Tardieu Scale. Results: Significant improvements were measured after diagnostic nerve block and botulinum toxin injection compared with the baseline condition. Diagnostic nerve block led to significantly greater improvements in all outcomes than botulinum toxin injection. Conclusion: This study confirmed diagnostic nerve block as a valuable screening tool in deciding whether to treat spastic equinovarus with botulinum toxin. However, the results support the evidence that diagnostic nerve block results in a greater reduction in muscle overactivity than does botulinum toxin type A in patients with spastic equinovarus due to stroke.

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

“…Furthermore, it may also be useful to define the dosage of botulinum toxin to inject. Indeed, DNB had been found to provide a significantly greater reduction in muscle overactivity than “on label” botulinum toxin treatment ( 12 ). Based on this information, one might infer about the dosage of botulinum toxin to administer, considering, for example, the injection of low doses in the case of weakness after DNB or the use of high doses in the case of good outcome after DNB (also higher than the labelled ones if the outcome of DNB is difficult to obtain).…”

Is the Outcome of Diagnostic Nerve Block Related to Spastic Muscle Echo Intensity? A Retrospective Observational Study on Patients with Spastic Equinovarus Foot

“…lidocaine 2% or bupivacaine 0.5%) is a diagnostic tool to obtain a transient suppression of muscle overactivity (i.e. the neurological disorder of spastic paresis) as a consequence of drug action on Ia fibres (which mediates the myotatic reflex) and alpha motor fibres (which mediates voluntary contraction) (3,13). In particular, the effect of anaesthetics is based on the block of depolarization by acting on the voltage-gated sodium channel, which determines a lack of calcium ions entry at the neuromuscular junction and, consequently, the impossibility of triggering the acetylcholine release process.…”

“…Selective DNB of the tibial nerve motor branches may be considered mandatory to evaluate and define the management of patients with spastic paresis with equinovarus foot (3). A relevant change in clinical pattern after DNB indicates muscle overactivity as the "main problem" (13,14). On the other hand, the development of spastic myopathy may lead to the progressive loss of response to myorelaxant procedure/treatments, such as selective DNB or BoNT-A injection (4,7).…”

The Application of Echo-Guided Injection of Steroid and Botulinum Toxin Type A for Ankle Contracture in Traumatic Trans-Metatarsal Amputation: A Case Report

“…Equinovarus deformity can be divided into congenital such as cerebral palsy and acquired which usually caused by stroke [5], traumatic brain injury or trauma. After echo-guided botulinum injection and proper rehabilitation program, most patient has significant improvement.…”