| dc.description.abstract | A broad range of surgical procedures involve working in areas proximal to vital nerves and neural structures. Currently, surgeons rely on their experience, anatomical knowledge, and visual assessment of the surgical field to identify and locate nerves. As a result, iatrogenic nerve injury (INI), the term given to inadvertent nerve damage inflicted by a clinician, is a prevalent surgical complication. Between 400,000-600,000 INIs are reported each year in the United State alone. During resections and biopsies, the incidence of INI can be staggeringly high reaching upwards of 60% for certain procedures. Consequently, in addition to the detrimental effects experienced by the patients, INIs are also a common source of malpractice litigation. To avoid these regrettable outcomes, intraoperative nerve monitoring (IONM) has been employed to recognize the onset of nerve damage. Because IONM relies on electrical stimulation, however, IONM suffers from stimulation artifacts and current spread that can lead to ambiguity in assessing the functional integrity of nerves. Moreover, there is currently no widely adopted means to enhance nerve visualization intraoperatively.
The goal of this doctoral research project is to develop methods to improve IONM and nerve visualization. To that end, this work utilizes infrared neural stimulation (INS) to enhance the sensitivity of IONM to the onset of nerve damage. Since INS is artifact-free and has a higher degree spatial selectivity than current clinical electrical stimulation methods, INS markedly improves the efficacy of IONM enabling earlier detection of nerve damage progression as compared to electrical stimulation. Additionally, to augment nerve visualization during surgery, this work employs diffuse reflectance spectroscopy (DRS) to discriminate nerves from surrounding tissue based on its unique endogenous optical properties. A ratiometric approach was developed using three optimal wavelengths for nerve discrimination that resulted accuracies > 91% in both rats and humans. With these capabilities, DRS along with INS could aid surgeons in reducing both the prevalence of INIs and the functional deficits experienced by patients. | |
