Spastic muscles show permanent contraction but also paradoxical muscular weakness. Compartmental muscular pressure in normal subjects oscillates between 0 and 5 mmHg.

To study compartmental pressure in the posterior superficial compartment of the leg in children with spastic paralysis, to identify its variations after a percutaneous tenotomy of the Achilles tendon, and to find any possible connection with arterial pressure or weight.

Twelve patients who had undergone a percutaneous tenotomy of the Achilles tendon were studied. Six of them were tetraplegic and three hemiplegic, with bilateral and unilateral tenotomies respectively. The following variables were taken into consideration: age, weight, systolic and diastolic arterial pressure and pressure of the superficial compartment of the leg, both pre- and post- tenotomy. The measurement of the compartmental pressure was taken using an automatic calibration monitor with an error of measure of ± 1 mmHg. Statistics: descriptive, non-parametric tests (Wilcoxon, Kruskall- Willis).

The average age was 9.3 years old, 11 in men and 7.5 in women. 89.5% of the total population was male and 10.5 % female. The average weight was 27.2 Kilograms, 28.1 Kg. in men and 20.5 Kg. in women. Systolic pressure was 94.1 mmHg and diastolic pressure 41.3 mmHg. Pre-tenotomy compartmental pressure was 12.1 mmHg and 7.9 mmHg post-tenotomy, decreasing 34.5 % (p= 0.08, N.S.). Systolic pressure had no relation to pre-tenotomy (r = −0.16) o post-tenotomy (r = −0.13) compartmental pressure. Diastolic pressure had no relation either (p =0.2 and r=−0.36), respectively. The pressure of the superficial compartment of the leg is higher than normal in spastic patients, decreasing, although not significantly, after a percutaneous tenotomy of the Achilles tendon is performed.