Vibrational Profiling of Brain Tumors and Cells.

This study reports vibration profiles of neuronal cells and tissues as well as brain tumor and neocortical specimens. A contact-free method and analysis protocol was designed to convert an atomic force microscope into an ultra-sensitive microphone with capacity to record and listen to live biological samples. A frequency of 3.4 Hz was observed for both cultured rat hippocampal neurons and tissues and vibration could be modulated pharmacologically. Malignant astrocytoma tissue samples obtained from operating room, transported in artificial cerebrospinal fluid, and tested within an hour, vibrated with a much different frequency profile and amplitude, compared to meningioma or lateral temporal cortex providing a quantifiable measurement to accurately distinguish the three tissues in real-time. Vibration signals were converted to audible sound waves by frequency modulation, thus demonstrating, acoustic patterns unique to meningioma, malignant astrocytoma and neocortex.

Improved transoral surgical tool design by CT measurements of the oral cavity and pharynx.

The majority of head and neck cancers arise from the oral cavity and oropharynx. Many of these lesions will be amenable to surgical resection using transoral approaches including transoral robotic surgery (TORS). To develop and control TORS tools, precise dimensions of the oral cavity and pharynx are desirable. CT angiograms of 76 patients were analyzed. For the oral cavity, only the maximum length and width were measured, while for the pharynx, the width, length, and areas of the airway were all measured and the volume calculated. A prototype TORS tool was developed and tested based on the findings and dimensions. The design modification of the tool is in progress. The mean male oral cavity width and length were 93.3 ± 4.3 and 77.0 ± 7.2 mm, respectively, and the mean male pharyngeal width, length, area, and volume were 26.5 ± 7.2 mm, 16.2 ± 8.8 mm, 325 ± 149 mm2, and 28,440 ± 14,100 mm3, respectively, while the mean female oral cavity width and length were 84.5 ± 12.9 and 71.0 ± 6.3 mm, respectively, and the mean female pharyngeal width, length, area, and volume were 24.8 ± 5.6 mm, 13.7 ± 3.2 mm, 258 ± 98 mm2, and 17,660 ± 7700 mm3, respectively. The developed TORS tool was tested inside the oral cavity of an intubation mannequin. These data will also be used to develop an electronic no-go cone-shape tunnel to improve the safety of the surgical field. Reporting the oral cavity and pharyngeal dimensions is important for design of TORS tools and creating control zones for the workspace of the tool inside the oral cavity.

Surgical Skill Assessment Using Motion Quality and Smoothness.

OBJECTIVES: This article presents a quantitative technique to assess motion quality and smoothness during the performance of micromanipulation tasks common to surgical maneuvers. The objective is to investigate the effectiveness of the jerk index, a derivative of acceleration with respect to time, as a kinetostatic measure for assessment of surgical performance. DESIGN: A surgical forceps was instrumented with a position tracker and accelerometer that allowed measurement of position and acceleration relative to tool motion. Participants were asked to perform peg-in-hole tasks on a modified O'Connor Dexterity board and a Tweezer Dexterity pegboard (placed inside a skull). Normalized jerk index was calculated for each individual task to compare smoothness of each group. SETTING: This study was conducted at Project neuroArm, Cumming School of Medicine, the University of Calgary. PARTICIPANTS: Four groups of participants (surgeons, surgery residents, engineers, and gamers) participated in the tests. RESULTS: Results showed that the surgeons exhibited better jerk index performance in all tasks. Moreover, the residents experienced motions closer to the surgeons compared to the engineers and gamers. One-way analysis of variance test indicated a significant difference between the mean values of normalized jerk indices among 4 groups during the performance of all tasks. Moreover, the mean value of the normalized jerk index significantly varied for each group from one task to another. CONCLUSIONS: Normalized jerk index as an independent parameter with respect to time and amplitude is an indicator of motion smoothness and can be used to assess hand motion dexterity of surgeons. Furthermore, the method provides a quantifiable metrics for trainee assessment and proficiency, particularly relevant as surgical training shifts toward a competency-based paradigm.

Evaluation of haptic interfaces for simulation of drill vibration in virtual temporal bone surgery.

Surgical training is evolving from an observership model towards a new paradigm that includes virtual-reality (VR) simulation. In otolaryngology, temporal bone dissection has become intimately linked with VR simulation as the complexity of anatomy demands a high level of surgeon aptitude and confidence. While an adequate 3D visualization of the surgical site is available in current simulators, the force feedback rendered during haptic interaction does not convey vibrations. This lack of vibration rendering limits the simulation fidelity of a surgical drill such as that used in temporal bone dissection. In order to develop an immersive simulation platform capable of haptic force and vibration feedback, the efficacy of hand controllers for rendering vibration in different drilling circumstances needs to be investigated. In this study, the vibration rendering ability of four different haptic hand controllers were analyzed and compared to find the best commercial haptic hand controller. A test-rig was developed to record vibrations encountered during temporal bone dissection and a software was written to render the recorded signals without adding hardware to the system. An accelerometer mounted on the end-effector of each device recorded the rendered vibration signals. The newly recorded vibration signal was compared with the input signal in both time and frequency domains by coherence and cross correlation analyses to quantitatively measure the fidelity of these devices in terms of rendering vibrotactile drilling feedback in different drilling conditions. This method can be used to assess the vibration rendering ability in VR simulation systems and selection of ideal haptic devices.

Quantifying force and positional frequency bands in neurosurgical tasks.

To establish the design requirements for an MR-compatible haptic hand-controller, this paper measures magnitudes and frequency bands of three mechanical motion and interaction components during the performance of neurosurgical tasks on a cadaveric brain. The hand-controller would allow the performance of virtual neurosurgical tasks within the bore of a high field magnet during image acquisition, i.e., functional MRI. The components are the position and the orientation of a surgical tool, and the force interaction between the tool and the brain tissue. A bipolar forceps was retrofitted with a tracking system and a set of force sensing components to measure displacements and forces, respectively. Results showed working positional, rotational, and force frequency bands of 3, 3 and 5 Hz, respectively. Peak forces of 1.4, 2.9 and 3.0 N were measured in the Cartesian coordinate system. A workspace of 50.1 × 39.8 × 58.2 mm(3) and orientation ranges of 40.4°, 60.1° and 63.1° for azimuth, elevation, and roll angles were observed. The results contribute in providing information specific to neurosurgery that can be used to effectively design a compact and customized haptic hand-controller reflecting characteristics of neurosurgical tasks.