Myoneural blockade is a well-established means of reducing tone in spastic muscles, thereby delaying or avoiding the need for operative intervention. The recent interest in botulinum A toxin has tended to obscure the fact that other agents such as alcohol have been used for many years to achieve a similar effect. Eighty-two children between the ages of 2 and 16 years with cerebral palsy underwent myoneural blocks using 45% ethanol for dynamic contracture of the hamstrings and/or gastrocnemius. The injections were performed under a light general anaesthetic, using a nerve stimulator to localise the myoneural junction. A total of 153 muscle groups were injected. Hamstring tightness improved as a result of ethanol injection, the popliteal angle reducing from a mean of 73° (range 40° – 90°) to 43° (range 10° – 70°). Gastrocnemius tightness also improved, the ankle dorsiflexion with knee extended improving from a mean of −7° to +3°. The maximal effect was achieved in a mean of 12 weeks and was maintained for a further 12 weeks before starting to deteriorate. The time from injection to the next intervention ranged from 13 weeks to over 2 years. There were no complications or adverse effects. The effect of any one therapy in cerebral palsy is difficult to establish, given that there are often several different modalities of treatment operating concurrently. However, the results from this series indicate that myoneural blockade with ethanol is a useful and safe adjunct to other therapies in the child with lower limb spasticity.
The role of three genetically distinct collagen types in the formation of endochondral bone and in calcification and resorption of cartilage has been assessed. Using antibodies specific to types I, II and III collagen we have demonstrated in the embryonic chick tibia that endochondral bone formation began with deposition of type III collagen in lacunae of hypertropic chondrocytes by invading bone-marrow-derived cells. This was followed by the deposition of type I collagen, which is the collagenous constituent of endochondral osteoid. At later stages of development endochondral osteoid was found in the epiphysial growth plate in apparently intact lacunae of hypertrophic chondrocytes; this indicated that the latter might contribute to the synthesis of osteoid type I collagen. Immuno-histological staining for collagen types, and von Kossa staining for calcium phosphate on parallel sections, demonstrated that type I and type II collagen matrices were substrates for calcification. Endochondral bone (with type I collagen) was found on scaffolding of both uncalcified and calcified cartilage (with type II collagen), indicating that calcification of endochondral osteoid and of the underlying cartilage occurred independentyl. Spicules of endochondral cancellous bone of a four-week-old chick contained a core of calcified type II collagen.
