Value of anaesthetic blocks in assessing spastic foot. A series of 64 motor blocks

Abstract

IntroductionAnaesthetic blocks are used by many teams for assessing spasticity and its complications.PatientsFifty nine patients with spastic foot were selected over a four and half year period (starting June 2003), from patients having attended a specialist consultation. The patients were aged 13 to 70 (average 42.6 ± 22 years), and presented the following ailments: cerebral palsy in 26 cases, stroke in 25 cases, brain injury in three cases, degenerative disease in three cases and spinal cord injury in two cases.MethodMotor blocks were performed with specific needles plus neurostimulator, using the technique for locating the tibialis posterior nerve and its branches. The anaesthetic used was mainly 2% non-adrenalized etidocaine (Xylocaïne®), which is generally effective and quick-acting. Spasticitywas analysed using theAshworth scale andwalking was assessed using Bessou’s locometer.ResultsSixty-four anaesthetic blocks were performed. Forty nine blocks were performed on the tibialis posterior nerve. The Ashworth modified scores constantly showed a decrease in spasticity (two points). The average gain in joint motion was 12.25, and in antagonist strength was 0.92 points. There was no significant improvement in walking speed or step length after the blocks. Results concerning quality and motor blocks were technique-dependent and required patient cooperation. Local anaesthetic blocks determined the relative contributions of over-activity and muscle shortening in generating pathological posture. Selective blocks help identify the muscle or muscles responsible for spastic patterns. There was no significant improvement in walking speeds following the blocks.ConclusionAnaesthetic motor blocks are a necessary and often decisive procedure as regards spastic foot assessment. They reveal the most spastic muscles and determine the relative contributions of overactivity and muscle shortening.