Optical Feedback Mechanism for Detecting Cerebrospinal Fluid Leaks During Spinal Surgery

abstract: For my honors thesis, I developed a proof of concept alpha prototype of a biomedical device for detection of cerebrospinal fluid leaks during spinal surgery. Cerebrospinal fluid leaks are a consequence of tears in the dura mater of the spinal cord and can result in potentially life-threatening conditions and are overall a large burden not only on the patient but upon the clinical teams managing the patient postoperatively. What I created was an optical sensor that I programmed to be sensitive to detecting green wavelength light. The device would ideally be attached to surgical drain tubing and used in conjunction with fluorescein (a green fluorescent dye) infused lumbar punctures into the spinal canal of patients. As the dye circulates through the spinal cord, any tears in the dura mater would cause the fluorescein to leak out with cerebrospinal fluid into the incision site. This fluid may then be collected by the surgical drain where the sensor may detect the fluorescein, triggering a buzzer response that would notify the patient or the surgeons of an ongoing leak that requires repair. The time I spent on my thesis involved sensor validation to ensure it could differentiate between colors, testing the sensor's color sensitivity by performing a fluorescein aliquot, and running proof of concept testing that could show the sensor can detect fluorescein drain tubing and provide an adequate response. The sensor was able to differentiate between varying concentrations of fluorescein in solution and provided exceptional results in its proof-of-concept testing. Next steps will be to re-run the sensor validation study with different dyes as well as consolidating the device's electrical hardware onto a single circuit board as development of beta and gamma prototypes move forward