Post anaesthetic myopathy/neuropathy in horses undergoing magnetic resonance imaging compared to horses undergoing surgery.
Authors: Franci P, Leece E A, Brearley J C
Journal: Equine veterinary journal
Summary
# Editorial Summary: Post-anaesthetic myopathy/neuropathy in horses undergoing MRI versus surgery Concerns that prolonged anaesthesia and non-surgical patient positioning during equine MRI might predispose to post-anaesthetic myopathy/neuropathy syndrome (PAMNS) led Franci and colleagues to compare PAMNS occurrence between 633 horses undergoing MRI and those anaesthetised for non-emergency, non-abdominal surgery between 2001 and 2005. Clinical signs of PAMNS were recorded in 8 MRI horses (2.3%, 95% CI: 1.1–4.2) versus 2 surgical horses (0.98%, 95% CI: 0.2–2.8), a difference that did not reach statistical significance despite an apparent 2.7-fold increased odds ratio in the MRI group. Whilst the study found no statistically significant difference in PAMNS risk between the two anaesthetic scenarios—despite MRI horses being heavier and surgical cases running longer—two MRI horses required euthanasia due to PAMNS severity, a clinically meaningful outcome that deserves consideration. For practitioners counselling clients on diagnostic anaesthesia, these findings suggest the procedural risk profile is comparable to surgical anaesthesia, though the absence of therapeutic benefit means PAMNS risk warrants careful individual case evaluation before proceeding with MRI as a diagnostic tool.
Read the full abstract on PubMed
Practical Takeaways
- •MRI anaesthesia carries similar overall risk of PAMNS to surgical anaesthesia, despite longer positioning times and different body placement requirements
- •Client communication should reflect that diagnostic MRI carries comparable post-operative complications to elective surgery—weigh benefits against risks carefully
- •While rare (≤2.3%), PAMNS remains a serious concern with potential for severe outcomes; ensure appropriate post-anaesthetic monitoring and client expectations in both MRI and surgical cases
Key Findings
- •PAMNS occurred in 2.3% (8/346) of horses undergoing MRI compared to 0.98% (2/287) undergoing surgery, but this difference was not statistically significant (P=0.3)
- •MRI horses were significantly heavier than surgery horses (P<0.0001), while anaesthetic duration was longer in the surgery group (P<0.004)
- •Two horses undergoing MRI required euthanasia due to severity of PAMNS
- •No statistically significant differences in other anaesthetic parameters, adverse events, or patient risk factors were identified between groups