Optimization of a vector quantization codebook for objective evaluation of surgical skill

Timothy Mkowalewski, Jacob Rosen, Lily Chang, Mika N. Sinanan, Blake Hannaford

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations


Surgical robotic systems and virtual reality simulators have introduced an unprecedented precision of measurement for both tool-tissue and toolsurgeon interaction; thus holding promise for more objective analyses of surgical skill. Integrative or averaged metrics such as path length, timeto- task, success/failure percentages, etc., have often been employed towards this end but these fail to address the processes associated with a surgical task as a dynamic phenomena. Stochastic tools such as Markov modeling using a 'white-box' approach have proven amenable to this type of analysis. While such an approach reveals the internal structure of the of the surgical task as a process, it requires a task decomposition based on expert knowledge, which may result in a relatively large/complex model. In this work, a 'black box' approach is developed with generalized cross-procedural applications., the model is characterized by a compact topology, abstract state definitions, and optimized codebook size. Data sets of isolated tasks were extracted from the Blue DRAGON database consisting of 30 surgical subjects stratified into six training levels. Vector quantization (VQ) was employed on the entire database, thus synthesizing a lexicon of discrete, task-independent surgical tool/tissue interactions. VQ has successfully established a dictionary of 63 surgical code words and displayed non-temporal skill discrimination. VQ allows for a more cross-procedural analysis without relying on a thorough study of the procedure, links the results of the black-box approach to observable phenomena, and reduces the computational cost of the analysis by discretizing a complex, continuous data space.

Original languageEnglish (US)
Title of host publicationMedicine Meets Virtual Reality 12 - Building a Better You
Subtitle of host publicationThe Next Tools for Medical Education, Diagnosis and Care
PublisherIOS Press
Number of pages6
ISBN (Print)1586034049, 9781586034047
StatePublished - 2004
Event4th Medicine Meets Virtual Reality Proceedings 1996, MMVR 1996 - Newport Beach, CA, United States
Duration: Jan 15 2004Jan 16 2004

Publication series

NameStudies in Health Technology and Informatics
ISSN (Print)0926-9630
ISSN (Electronic)1879-8365


Other4th Medicine Meets Virtual Reality Proceedings 1996, MMVR 1996
Country/TerritoryUnited States
CityNewport Beach, CA


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