Quantifying Anatomic Deformations During Laryngoscopy

Abstract

For a variety of head and neck cancers, specifically those of the oropharynx, larynx, and hypopharynx, minimally invasive trans-oral approaches have been developed to reduce perioperative and long-term morbidity. However, in trans-oral surgical approaches anatomical deformation due to instrumentation, specifically placement of laryngoscopes and retractors, present a significant challenge for surgeons relying on preoperative imaging to resect tumors to negative margins. Quantifying the deformation due to instrumentation is needed in order to develop predictive models of operative deformation. In order to study this deformation, we used a CT/MR-compatible laryngoscopy system in concert with intraoperative CT imaging. 3D models of preoperative and intraoperative anatomy were generated. Mandible and hyoid displacements as well as tongue deformations were quantified for eight patients undergoing diagnostic laryngoscopy. Across patients, we found on average 1.3 cm of displacement for these anatomic structures due to laryngoscope insertion. On average, the maximum displacement for certain tongue regions exceeded 4 cm. The anatomical deformations quantified here can serve as a reference for describing how the upper aerodigestive tract anatomy changes during instrumentation and may be helpful in developing predictive models of intraoperative upper aerodigestive tract deformation.

Multi-modal Framework for Image-guided Trans-oral Surgery with Intraoperative Imaging and Deformation Modeling

“…3D reconstructions of key anatomical structures (skull, mandible, hyoid, tongue, and airway) and tongue fiducials were generated from both preoperative and intraoperative scans of the patients. The preoperative and intraoperative scans were registered to a coordinate system (FMV [16]) via the skull. Bony structure (mandible, hyoid) displacement, tongue movement, and airway volume change were evaluated.…”

“…In this work, we introduce a proof-of-concept framework for surgical navigation that includes intraoperative imaging and deformation modeling with the aim of improving the efficacy of TOS. A custom-designed CT-compatible laryngoscopy system developed in our lab [16] enables intraoperative imaging, evaluation of intraoperative tissue deformation, and intraoperative surgical navigation [17]. Pressure sensors incorporated onto a laryngoscope provide real-time force measurements during the procedure.…”

Radiation exposure alters airway deformability and bony structure displacement during laryngoscopy

“…For the translational and rotational analysis of the mandible and hyoid, each patient's skull was registered to a coordinate system defined by the frankfurt plane, midsagittal plane, and vertical porion plane coordinate. 12 Center displacements (T x , T y , T z , and magnitude T) and rotations (A x , A y , A z ) of the mandible and hyoid bones from the "uninstrumented" and "instrumented" states were computed via iterative closest point (ICP) rigid registration. 13…”

Initial experience with image‐guided surgical navigation in transoral surgery

“…This, in turn, renders the preoperative imaging unusable for image registration during surgery. 3,4 In order to better study this complex problem, we have developed a CT and MRI-compatible 3D-printed polymer laryngoscope, described previously. 5 This laryngoscope allows for intraoperative imaging with the scope in suspension, potentially allowing for more accurate image registration.…”

“…This, in turn, renders the preoperative imaging unusable for image registration during surgery. 3,4 In order to better study this complex problem, we have developed a CT and MRI-compatible 3D-printed polymer…”