Blood glucose monitoring during surgery in dogs to assess completeness of surgical resection of insulinoma: 11 cases.

Objective: To evaluate whether intraoperative detection of rising levels of blood glucose could improve the completeness of resection of insulin-secreting tumor tissue and whether this improves long-term outcomes.

Animals: 11 client-owned dogs diagnosed with insulinoma.

Procedures: Retrospective review of medical records of dogs undergoing partial pancreatectomy as treatment for insulinoma. A blood glucose reading was obtained at induction, following removal of the pancreatic mass and/or after each suspected metastatic lesion until blood glucose had normalized. Disease-free interval and survival time were measures of outcome.

Results: A positive increase in blood glucose was detected in all cases, with a mean rise of 6.35 ± 4.5 mmol/L. Mean follow-up was 611 days, mean disease-free interval was 382 days, and median survival time was 762 days. Tumor stage was not associated with outcome. Three cases underwent a second surgery (metastasectomy), achieving further prolongation of disease-free survival.

Clinical Relevance: A sustained increase in intraoperative blood glucose provided the surgeon with confidence of more complete resection of insulinoma tissue and resulted in improved outcomes in all cases included in this study. Subsequent metastasectomy of recurrent insulinoma lesions also provided good outcomes. Intraoperative monitoring of blood glucose during surgical treatment of insulinoma resulted in the surgeon continuing to explore and resect abnormal tissue until an increase of glycemia was observed. This was shown to provide the surgeon with more confidence of resection of all active insulinoma tissue and improved clinical outcomes.