Risk of iatrogenic damage to the sciatic nerve in dairy cattle
Sciatic nerve damage in cattle could lead to pain, paralysis and lameness, creating welfare and productivity issues. Damage following intramuscular injection is highlighted in some clinical texts although there is no indication of prevalence. This cross-sectional study investigated the anatomical size and position of the sciatic nerve in four dairy cattle type cadavers. To evaluate the risk of iatrogenic damage, 54 participants placed needles in the dorsal gluteal region of two cadavers each, as per their routine intramuscular injection method. The distance from needle tip to the sciatic nerve was estimated for each. Sixty-nine per cent of injections were placed within 5 cm of the sciatic nerve. Direct nerve puncture occurred in the cadaver in poorest body condition. A short questionnaire revealed that 70 per cent of the participants regularly used the dorsal gluteal region for intramuscular injection and 50 per cent commonly used a volume of ≥20 mL at a single site. It is concluded that the sciatic nerve is at considerable risk of iatrogenic damage. The neck should be promoted as the optimum site for intramuscular injection and improved guidelines are required if the gluteal region is to remain in common use. A lateral site, between the tuber coxae and tuber ischium, is recommended.