Outcome After Intracranial Surgery

Intracranial surgery is indicated most frequently in dogs for tumor removal or management of traumatic injury. Surgical patients typically require intensive postoperative care due to increased risk of complications, including aspiration pneumonia and neurologic deterioration.

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Researchers in the United Kingdom recently performed a retrospective study to evaluate survival and postoperative outcome in canine patients after intracranial surgery at a referral center.

Study Design

The investigators identified dogs that underwent intracranial surgery based on findings from physical and neurologic examination, blood work, and magnetic resonance imaging or computed tomography. Patients recovered in the center’s intensive care unit (ICU) and were monitored every 2 hours, repositioned every 4 hours, and administered eye lubrication every 4 hours. To avoid risk of increased intracranial pressure, no neck leads or jugular venipuncture was allowed, and parenteral nutrition was provided until patients regained adequate mentation for assisted feeding.

The investigators performed statistical analyses to determine whether variables such as patient signalment, diagnosis, and surgical details influenced duration of hospitalization, survival to discharge, and development of postoperative complications.

Results

Thirty-one male and 19 female dogs were included in the study, with a median age and weight of 9 years and 25.3 kg, respectively. At presentation, most dogs had 1 or more neurologic abnormalities, including history of seizures (68%), abnormal mentation (40%), proprioceptive deficits (40%), 1 or more cranial nerve deficits (32%), and ataxia of all limbs (30%).

Reasons for intracranial surgery were as follows: neoplasm removal (72%), intracranial empyema (10%), decompression from traumatic injury (8%), excisional biopsy (4%), foramen magnum decompression (4%), and removal of an intracranial arachnoid diverticulum (2%). Eighty-six percent of neoplasms were meningiomas. Surgical approach was temperoparietal (50%), transfrontal (44%), or suboccipital (6%). Mean surgery time was 184 minutes (range, 70-365 minutes).

Two dogs required blood transfusion during surgery due to intracranial hemorrhage, and IV mannitol was administered to 78% of patients during surgery. All dogs received postoperative analgesia in the form of methadone with or without paracetamol, and 54% and 68% of patients received preoperative and postoperative glucocorticoids, respectively, to reduce either vasogenic edema or inflammation.

Survival data were as follows:

• One dog did not recover from anesthesia due to suspected malignant hyperthermia syndrome.
• Two dogs developed fatal aspiration pneumonia.
• One dog that was comatose before surgery died of cardiac arrest 6 days after surgery.
• Forty-six dogs survived to discharge.

Forty-five percent of dogs showed early postoperative neurologic deterioration that was typically mild. The most common nonneurologic postoperative complication, observed in 12% of dogs, was aspiration pneumonia. Median duration of ICU care and hospitalization was 1 and 5 days, respectively.

Statistical analyses were limited by the high survival rate; however, multivariate models revealed that dogs with nonneurologic complications, higher postoperative glucose, or lower preoperative pulse rate were hospitalized longer than were other dogs.

Major Conclusion

The study concluded that nearly all dogs undergoing intracranial surgery survived to discharge and experienced postoperative complications that were typically short-lived and mild.

Dr. Stilwell received her DVM from Auburn University, followed by a MS in fisheries and aquatic sciences and a PhD in veterinary medical sciences from the University of Florida. She provides freelance medical writing and aquatic veterinary consulting services through her business, Seastar Communications and Consulting.