Neurosurgery
Welcome to the Chopko Lab

Welcome to the Chopko Lab

My clinical research interests include the fields of degenerative spinal conditions, neuro-oncology and minimally invasive techniques, including endovascular approaches to nervous system disease.

1. Lumbar spinal degenerative disease.

As our population ages, degenerative spinal conditions become a more prominent issue. One common problem, lumbar spinal stenosis, affects over 300,000 new patients every year, and can lead to a marked reduction in quality of life. A coexistent issue with advancing age is medial frailty, with a segment of the population unable to endure conventional open spinal surgery without excessive or prohibitive risk. I have been exploring newer, less invasive approaches to treatment of lumbar spinal stenosis, with the hopes of being able to offer treatment to patients regardless of operative risk profile. One technique, the percutaneous resection and remodeling of the ligamentum flavum, shows promise as a technique for subtly expanding the spinal canal using image-guided techniques and local anesthesia. In patients suffering from axial lumbar spinal pain from diseased facet joints, I am researching in an outpatient setting, using exploring the concept of short-segment pedicle srew instrumented fusions in an outpatient setting under local anesthesia and minimal sedation, This technique was made possible by the introduction of new percutaenous instrumentation systems.

2. Local-Regional Cancer Therapy Strategies.

The local-regional approach to cancer treatment is based on the concept of delivering treatment in a very precise manner to the tumor target while minimizing the “collateral” damage to normal tissues and organs. One approach is the implantation of anti-neoplastic agents directly into the tumor site. Generally, this approach is highly dependent on effectively packaging the drug, so that high concentration of drug is released for short distances over time. In the treatment of the nervous system disease, one available format is the drug carmustine (CCNU) as packaged in a polymeric wafer. This approach has been used since the 1990’s in the treatment of glioblastoma and anaplastic astrocytoma, both highly malignant primary brain tumors. I have pursued a pilot study  utilizing carmustine wafers as an adjunct  to debulking surgery for metastatic tumors of the vertebral column, such as breast and lung cancers. The hope is that in the future, different drugs can also be packaged in a polymeric release form, so as to better tailor treatment to a broader spectrum of tumors.

A different approach relies on the delivery of anti-neoplastic agents directly into the arterial blood supply of a tumor mass. Modern endovascular techniques are used to navigate a delivery system called a microcatheter into a tumor’s dominant blood supply, and the procedure is referred to as “intra-arterial chemotherapy (IAC)” . Once in position, the tumor bed is then flooded with the chemotherapeutic agent. In certain cases, such as the drug cisplatin , the simultaneous administration of a chelating agent, sodium thiosulfate, neutralizes any excess cisplatin that has passed through the tumor bed into the venous circulation. This strategy further reduces, if not eliminates, the damage to normal tissue, and is referred to as “organ-sparing.”  IAC has been quite effective in the treatment of newly diagnosed as well as recurrent head and neck squamous cell carcinomas. I have extended this approach to the treatment of spinal vertebral metastases, when the conventional treatment options had been exhausted. The IAC approach could also be useful in the future to provide novel therapeutic agents, such as anti-sense agents or viral vectors,  directly into a tumor site.

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