AJVR, Vol 72, No. 1, January 2011 109 C onventional craniotomy procedures in veterinary patients do not facilitate resection of deep brain tumors without damage to overlying brain tissue. Al- though conventional stereotactic brain biopsy methods may spare extratumoral tissue, they do not allow for rapid resection of large tumors. Therefore, less invasive techniques are needed for biopsy and resection of deep brain tumors to reduce procedural duration, collateral tissue damage, and adverse effects associated with the surgical approach. Evaluation of minimally invasive excisional brain biopsy and intracranial brachytherapy catheter placement in dogs Rebecca A. Packer, MS, DVM; Lynetta J. Freeman, DVM, MS; Margaret A. Miller, DVM, PhD; Amy E. Fauber, DVM, MS; Wallace B. Morrison, DVM, MS Objective—To evaluate a technique for minimally invasive excisional brain biopsy and intra- cranial brachytherapy catheter placement in dogs. Animals—5 healthy adult female dogs. Procedures—Computed tomographic guidance was used to plan a biopsy trajectory to a selected area of brain with reference to a localizer grid. The procedure was performed through a 1-cm skin incision and 6-mm burr hole by use of a 9-gauge biopsy device. Five cylindrical samples (3 to 4 mm in diameter and 7 to 12 mm in length) were removed over 5 cycles of the vacuum-assisted tissue excision system, leaving approximately a 2-cm 3 resec- tion cavity. A balloon-tipped intracranial brachytherapy catheter was placed through the burr hole into the resection cavity, expanded with saline (0.9% NaCl) solution, and explanted 7 days later. Results—4 of 5 dogs survived the procedure. The fifth died because of iatrogenic brain damage. Neurologic deficits were unilateral and focal. Twenty-four hours after surgery, all surviving dogs were ambulatory, 2 dogs exhibited ipsiversive circling, 4 had contralateral proprioceptive deficits, 3 had contralateral menace response deficits, 2 had a reduced con- tralateral response to noxious nasal stimulation, and 1 had dull mentation with intermittent horizontal nystagmus and ventrolateral strabismus. Neurologic status improved throughout the study period. Histologic quality of biopsy specimens was excellent. Conclusions and Clinical Relevance—This technique enabled histologic diagnosis from high-quality biopsy specimens obtained through a minimally invasive technique and has potential applications for multimodal treatment of deep brain tumors in dogs. (Am J Vet Res 2011;72:109–121) Current glioma treatment options in humans in- volve invasive surgery deep within brain tissue and aggressive chemotherapy and external beam radiation protocols that usually result in poor long-term out- comes, particularly for patients with high-grade glio- mas. 1–3 Treatment options for veterinary patients with gliomas are often limited by the tissue trauma induced by invasive surgical approaches that require dissection through normal brain tissue to access deep tumors. As a result, definitive treatment for veterinary patients with gliomas is often limited to external beam radiation ther- apy and chemotherapy. For these reasons, less invasive treatment methods for deep brain tumors are needed to minimize adverse effects without sacrificing outcome. Minimally invasive stereotactic brain biopsy pro- cedures are available for veterinary patients; howev- er, none are used for tumor resection because of the small-gauge needles that preclude efficient tissue re- section and compromise biopsy specimen quality. 4–12 Neuroendoscopic procedures for brain tumor biopsy Received August 21, 2009. Accepted November 25, 2009. From the Departments of Veterinary Clinical Sciences (Packer, Free- man, Fauber, Morrison), Basic Medical Sciences (Packer), and Comparative Pathobiology (Miller), School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907. Supported by the Purdue University School of Veterinary Medicine Small Animal Disease Research Grant, with technical support and material donations from Hologic Incorporated, and material dona- tions from Cytyc Corporation. Presented in abstract form at the 26th Annual Forum of the American College of Veterinary Internal Medicine, San Antonio, Tex, June 2008. The authors thank Kris L. Davis, Jason T. Pavloff, and Gerald L. Carpenter for technical support and Natasha J. Olby for technical assistance. Address correspondence to Dr. Packer (rpacker@purdue.edu). ABBREVIATIONS CT Computed tomography GFAP Glial fibrillary acidic protein MRI Magnetic resonance imaging Unauthenticated | Downloaded 08/28/22 01:51 AM UTC