In Vivo Evaluation of a CT-Compatible Retractor for Image Guided Trans-Oral Surgery

This study will include four stages of data collection: 1) Subject history, 2) intraoperative surgical working volume (SWV) assessment with stereoendoscopy and standard-of-care metal retractor, 3) intraoperative surgical working volume assessment with stereoendoscopy and 3D-printed polymer retractor, 4) intraoperative surgical working volume assessment with CT-imaging and 3D-printed polymer retractor.

The investigators will conduct a comparative study examining differences in surgical exposure within the same patient when retraction is enabled through use of standard-of-care metal retractor vs. our 3D printed retractor. Patients to be recruited for the study will include those who present to the Head and Neck Tumor Clinic at Dartmouth-Hitchcock Medical Center (DHMC) with suspicious lesions identified in the oropharynx, hypopharynx or larynx. Currently the clinic sees about 20 patients per month that are scheduled for staging endoscopy in the operating room. Consent will be obtained from all participating subjects prior to participation.

All surgeries will be performed at the Center for Surgical Innovation. Prior to surgery a standard-of-care Feyh-Kastenbauer (FK) or Crowe-Davis (CD) metal retractor will be positioned in the mouth of the patient and stabilized in suspension. A standard-of-care stereo vision endoscope will capture images of the oral cavity so that a 3D volume of the surgical working volume (SWV) can be measured. The time to place the retractor and surgical working volume metrics based on stereovision derived oral-cavity volumes and inter-incisive distance (IID) will be recorded. The FK and/or CD retractor will then be removed and replaced with our custom 3d-printed radiolucent retractor. The time to place this retractor and surgical working volume metrics based on stereovision derived oral-cavity volumes and inter-incisive distance will be recorded. A single CT scan with IV contrast will be obtained with the retractor in place and suspended. The standard surgical procedure will commence following routine methods. Following surgery, a second set of surgical working volume metrics based on stereovision derived oral-cavity volumes and inter-incisive distance will be recorded.