title: Vision-based deformation recovery for intraoperative force estimation of tool-tissue interaction for neurosurgery.
abstract: OBJECTIVE
  In microsurgery, accurate recovery of the deformation of the surgical environment is important for mitigating the risk of inadvertent tissue damage and avoiding instrument maneuvers that may cause injury. The analysis of intraoperative microscopic data can allow the estimation of tissue deformation and provide to the surgeon useful feedback on the instrument forces exerted on the tissue. In practice, vision-based recovery of tissue deformation during tool-tissue interaction can be challenging due to tissue elasticity and unpredictable motion.
  
  
  METHODS
  The aim of this work is to propose an approach for deformation recovery based on quasi-dense 3D stereo reconstruction. The proposed framework incorporates a new stereo correspondence method for estimating the underlying 3D structure. Probabilistic tracking and surface mapping are used to estimate 3D point correspondences across time and recover localized tissue deformations in the surgical site.
  
  
  RESULTS
  We demonstrate the application of this method to estimating forces exerted on tissue surfaces. A clinically relevant experimental setup was used to validate the proposed framework on phantom data. The quantitative and qualitative performance evaluation results show that the proposed 3D stereo reconstruction and deformation recovery methods achieve submillimeter accuracy. The force-displacement model also provides accurate estimates of the exerted forces.
  
  
  CONCLUSIONS
  A novel approach for tissue deformation recovery has been proposed based on reliable quasi-dense stereo correspondences. The proposed framework does not rely on additional equipment, allowing seamless integration with the existing surgical workflow. The performance evaluation analysis shows the potential clinical value of the technique.
authors.affiliation: The Hamlyn Centre for Robotic Surgery, Imperial College London, London, SW7 2AZ, UK. stamatia.giannarou@imperial.ac.uk.
authors.forename: Stamatia
authors.initials: S
authors.lastname: Giannarou
authors.affiliation: The Hamlyn Centre for Robotic Surgery, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Menglong
authors.initials: M
authors.lastname: Ye
authors.affiliation: The Hamlyn Centre for Robotic Surgery, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Gauthier
authors.initials: G
authors.lastname: Gras
authors.affiliation: The Hamlyn Centre for Robotic Surgery, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Konrad
authors.initials: K
authors.lastname: Leibrandt
authors.affiliation: The Hamlyn Centre for Robotic Surgery, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Hani J
authors.initials: HJ
authors.lastname: Marcus
authors.affiliation: The Hamlyn Centre for Robotic Surgery, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Guang-Zhong
authors.initials: GZ
authors.lastname: Yang
mesh_terms: D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008866:Microsurgery / Q000379:methods*; D008962:Models, Theoretical; D019635:Neurosurgical Procedures / Q000379:methods*; D019047:Phantoms, Imaging; D025321:Surgery, Computer-Assisted / Q000379:methods*
keywords: 3D stereo reconstruction; Deformation recovery; Force estimation; Soft tissue tracking