Minimally Invasive Theranostic Device for Brain Neuro-Oncology

Gamo, N., Chesapaek Vision
Zhang, X., Johns Hopkins University
Ellens, N., Johns Hopkins University
Miller, P., Johns Hopkins University SOM
Iyer, R., Johns Hopkins University
Groves, M., Johns Hopkins University
Cohen, A., Johns Hopkins Univeristy
Brem, H., Johns Hopkins University SOM
Clinical problem: Most brain surgeries involving deep tumors/cyst resections are performed using invasive craniotomies, the surgical removal of part of the bone from the skull to expose the brain. These invasive surgeries entail hours of blood loss, potential infections, long recovery periods, and the need for an additional cranioplasty surgery later on. While several devices using high-intensity focused ultrasound (HIFU), that is, high-energy ultrasonic waves focused to destroy brain targets through coagulation necrosis, are in various testing phases, they suffer from drawbacks in versatility, cost, and hurdles in the regulatory approval pathway. Most of the problems with current transcranial technology result from the attenuation of ultrasound while passing through the skull, and the inability to reach targets deep in the brain without significant risk. In particular, the use of excessive power is undesirable from an FDA regulatory standpoint.

Our solution: Our proposed technology overcomes these shortcomings by using the lateral ventricles as “room to work” to place a specially designed ultrasound transducer to target diseased brain areas. The ventricles can be accessed through a minimally invasive surgical approach that has previously been shown to be associated with low risk and short recovery. The novelty of this approach lies in the fact that it eliminates the need for ultrasound waves to pass through the skull, minimizing the electrical power necessary and thus engineering complexity and cost, improving device efficiency and patient outcome. Our simulations to date have determined the appropriate power and heat parameters to precisely create a lesion in a heterogeneous medium volume simulating cerebrospinal fluid and brain tissue. Importantly, our system can provide the same efficiency of treatment with 2 orders of magnitude less power than with the transcranial approach. Thus, our solution presents a compromise between power and regulatory approval. We envision a single-use, flexible catheter with a hybrid transducer tip that will interface with existing ultrasound equipment to both visualize the surgery site and emit therapeutic focused ultrasound.

IP analysis: Our provisional patent application is the first of its kind to report an insertable ultrasound therapeutic transducer through a minimally invasive burr hole into the ventricular space of the brain to focus on lesions. Other HIFU tools target the brain in a transcranial manner or target other organs, while another tool uses MRI to guide laser-mediated brain surgery. Thus, we have freedom to operate for an intracranial ultrasound transducer.

Market opportunity: Benign brain tumors, which tend to have defined borders and thus would benefit from our tool, make up almost 80% of 688,096 brain tumor cases currently in the US, and are mostly treated via craniotomy. The challenge here will be obtaining a Class III PMA approval from the FDA.

Keywords: minimally invasive, focused ultrasound, HIFU, neurosurgery, brain tumor, neuro-oncology, craniotomy