Mo Jai is a handsome, confident 10 year old Samoyed that required surgical amputation of one of his front legs due to an aggressive bone tumour. The tumour and limb were successfully removed and there no issues recovering after surgery. However, Mo Jai’s owners noticed increased sudden episodes of crying, waking up at night, and limping despite a healed surgical wound.
Mo Jai presented to the Animal Pain Relief Clinic (APRC) at Harvest Veterinary Oncology Centre (HVOC) for worsening pain four weeks after surgery despite being on pain medications. Under the management of Veterinary Pain Specialist and Head of Anaesthesia Dr Christopher Sun, a detailed assessment was performed for Mo Jai’s pain. Based on the The Canine Postamputation Pain (CAMPPAIN) score (Boesch et al 2021) and physical examination, Mo Jai was diagnosed as most likely to have post-amputation phantom limb pain.
Phantom limb pain is well described in human amputees but is poorly documented in dogs amputees. It is estimated that up to 14% of dogs experience pain for up to 6 months after amputation (Menchetti et al 2017), but associated with severe consequences if left untreated. Phantom limb pain is also commonly confused with surgical pain, which should subside with wound healing. If untreated, phantom limb pain can lead to permanent behavioural changes, aggression and chronic neuropathic pain which can negatively affect the pet-owner relationship.
Dr Christopher treated Mo Jai’s phantom limb pain with an interventional locoregional nerve block using long acting pain relief medications. An ultrasound guided subscalenic brachial plexus nerve block was performed under sedation to specifically inject the medication towards the nerves causing the maladaptive pain signals in the amputated region. This allowed a reduction in oral pain relief medications and side effects caused by those oral medications. In addition, an analgesic infusion was performed to reduce pain signals from causing hypersensitivity and also resetting pain receptors towards their normal state.
Mo Jai recovered smoothly from the interventional procedure and his pain condition vastly improved the next few days demonstrated by low pain scores, reduced anxiety and ability to sleep. He is now pain free and continuing his cancer treatment journey at HVOC.
