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EP-4018947-B1 - PLANNING SYSTEMS AND METHODS FOR PLANNING A SURGICAL CORRECTION OF ABNORMAL BONES

EP4018947B1EP 4018947 B1EP4018947 B1EP 4018947B1EP-4018947-B1

Inventors

  • JARAMAZ, BRANISLAV
  • NIKOU, CONSTANTINOS

Dates

Publication Date
20260506
Application Date
20140307

Claims (14)

  1. A method (600) for surgical planning, the method (600) comprising: receiving (510) an abnormal bone representation, the abnormal bone representation including a data set representing the abnormal bone; receiving (520) a generic normal bone model, the generic normal bone model (440) including a data set representing a normal bone having an anatomical origin comparable to an anatomical origin of the abnormal bone; registering (530) the generic normal bone model (440) to the abnormal bone representation, wherein registering the generic normal bone model (440) to the abnormal bone representation comprises: partitioning the generic normal bone model (440) and the abnormal bone representation into a plurality of segments, identifying from the segments of the abnormal bone representation an anatomical abnormity-free registration area (451), transforming (608) the generic normal bone model (440) to create the registered generic bone model (450) using a comparison between the abnormity-free registration area (451) and a corresponding segment of the registered generic bone model (450), matching (609) the abnormity-free registration area (451) of the abnormal bone to a corresponding segment of the registered generic bone model (450), and aligning (610) the remaining segments of the registered generic bone model (450) with the remaining segments of the abnormal bone based at least in part on the matching; detecting (540) at least one abnormal bone region (452) of the abnormal bone using a comparison between corresponding segments in the registered generic normal bone model (450) and the abnormal bone representation; forming (550) a surgical plan for surgically altering the at least one abnormal bone region.
  2. The method (600) of claim 1, wherein receiving the generic normal bone model (440) includes creating (606) statistical shape-based model using a plurality of images of normal bones of comparable anatomical origin from a group of subjects having normal bone anatomy.
  3. The method (600) of claim 2, wherein the plurality of images comprise at least one of two-dimensional or three-dimensional medical images.
  4. The method (600) of claim 2 or claim 3, wherein the medical images comprise a plurality of images collected from a group of subjects having at least one of a common age, common gender, common ethnicity, common body size, and other common relevant physical or demographic features with a patient for whom the surgical plan is being generated.
  5. The method (600) of any of claims 2 to 4, wherein the statistical shape-based model of the normal bone comprises a model of a desired post-operative shape or a desired post-operative appearance for the bone for which the surgical planning is to be conducted.
  6. The method (600) of any preceding claim, further comprising generating a graphical representation illustrating one or more of the generic normal bone model, the abnormal representation, or the surgical plan, the graphical representation providing feedback to enable a system user to accept or modify the surgical plan
  7. A surgical planning system (100) comprising: an input interface (120) configured to receive an abnormal bone representation, the abnormal bone representation including a data set representing the abnormal bone; a model receiver module (110) configured to receive a generic normal bone model, the generic normal bone model (440) comprising a data set representing a normal bone having an anatomical origin comparable to an anatomical origin of the abnormal bone; a registration module (131) configured to: register the generic normal bone model (440) to the abnormal bone representation, wherein registering the generic normal bone model (440) to the abnormal bone representation comprises: partitioning both of the generic normal bone model (440) and the abnormal bone representation each into a plurality of segments, identifying from the segments of the abnormal bone representation an anatomical abnormity-free registration area (451), transforming (608) the generic normal bone model (440) to create the registered generic bone model (450) using a comparison between the abnormity-free registration area (451) and a corresponding segment of the registered generic bone model (450); matching (609) the abnormity-free registration area (451) of the abnormal bone to a corresponding segment of the registered generic bone model (450), and aligning (610) the remaining segments of the registered generic bone model (450 with the remaining segments of the abnormal bone based at least in part on the matching; an abnormity detection module (320) configured to detect at least one abnormal bone region (452) of the abnormal bone using a comparison between corresponding segments of the registered generic normal bone model (440) and the abnormal bone representation, and a surgical plan formation module (132) configured to generate a surgical plan for altering the at least one abnormal bone region (452).
  8. The surgical planning system (100) of claim 7, further comprising a normal bone model generator configured to generate a statistical shape-based model of the normal bone using a plurality of images of normal bones of comparable anatomical origin from a group of subjects having normal bone anatomy.
  9. The surgical planning system (100) of claim 8, wherein the images comprise at least one of an x-ray image, an ultrasound image, a computed tomography (CT) image, a magnetic resonance (MR) image, a positron emission tomography (PET) image, a single-photon emission computed tomography (SPECT) image, and an arthrogram image.
  10. The surgical planning system (100) of claim 8 or 9, wherein the medical images comprise a plurality of images collected from a group of subjects having at least one of a comparable age, comparable gender, comparable ethnicity, comparable body size, and other comparable relevant physical or demographic features with a patient for whom the osteoplastic surgical plan is being generated.
  11. The surgical planning system (100) of any of claims 8 to 10, wherein each of the partitions of the partitioned normal bone model and abnormal bone representation are labelled to a specific characteristic comprising at least one of shape, anatomical structure, and intensity.
  12. The surgical planning system (100) of any of claims 8 to 11, wherein the statistical shape-based model of the normal bone comprises a model of a desired post-operative shape or a desired post-operative appearance for the bone for which the osteoplastic surgical planning is to be conducted.
  13. The surgical planning system (100) of any of claims 7 to 12, further comprising an interface coupled to the memory circuit (140), wherein the interface is configured to generate a graphical representation of at least one of the generic normal bone model (440), the abnormal representation, and the surgical plan.
  14. The surgical planning system (100) of claim 13, wherein the interface comprises a user input interface (120) configured to receive an input indicating an acceptance or requesting a modification of the surgical plan.

Description

RELATED APPLICATIONS This Patent Application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 61/779,805, filed on March 13, 2013. TECHNICAL FIELD This document relates generally to computer-aided orthopedic surgery, and more specifically to systems and methods for generating surgical plan for altering an abnormal bone using generic normal bone models. BACKGROUND The use of computers, robotics, and imaging to aid orthopedic surgery is well known in the art. There has been a great deal of study and development of computer-aided navigation and robotics systems used to guide surgical procedures. For example, a precision freehand sculptor (PFS) employs a robotic surgery system to assist the surgeon in accurately cutting the prosthesis into a desired shape. In interventions such as total hip replacement, computer-aided surgery techniques have been used to improve the accuracy, reliability of the surgery. Orthopedic surgery guided by images has also been found useful in preplanning and guiding the correct anatomical position of displaced bone fragments in fractures, allowing a good fixation by osteosynthesis. Femoral acetabular impingement (FAI) is a condition characterized by abnormal contact between the proximal femur and rim of the acetabulum. In particular, impingement occurs when the femoral head or neck rubs abnormally or does not have full range of motion in the acetabular socket. It is increasingly suspected that FAI is one of the major causes of hip osteoarthritis. Cam impingement (CI) and pincer impingement are two major classes of FAI. CI results from pathologic contact between an abnormally shaped femoral head and neck with a morphologically normal acetabulum. The femoral neck is malformed such that the hip range of motion is restricted and the deformity on the neck causes the femur an acetabular rim to impinge on each other. This can result in irritation of the impinging tissues and is suspected as one of the main mechanisms for development of hip osteoarthritis. Pincer impingement is the result of contact between an abnormal acetabular rim and a typically normal femoral head-neck junction. This pathologic contact is the result of abnormal excess of growth of anterior acetabular cup. This results in decreased joint clearance and repetitive contact between the femoral neck and acetabulum, leading to degeneration of the anterosuperior labrum. The web page "Planning Femoro-Acetabular Impingement Surgery",published online on 6 March 2013 at http://www1.imperial.ac.uk/ msklab/research/surgicaltechniques /femero_acetabularimpingementsurgery/ describes a planning aid using 3D models of the femoral head. EP 2767252A1 forms a prior right under Article 54(3) EPC, and describes software used to plan the correction of bone deformities preoperatively or postoperatively. The online article HOELPER B. M. ET AL: "Enhancing accuracy of magnetic resonance image fusion by defining a volume of interest",NEURORADIOLOGY, [Online] vol. 45, no. 11, 1 November 2003 (2003-11-01), pages 804-809, ISSN: 0028-3940, DOI: 10.1007/s00234-003-1071-4, retrieved from the Internet: at http://link.springer.com/article/10.1007/s00234-003-1071-4/fulltext.html describes a method of enhancing the accuracy of magnetic resonance image fusion by defining a volume of interest. SUMMARY Arthroscopic or open surgery interventions have been developed for treating FAI. The goal of surgical intervention is to relieve the impingement by increasing hip clearance in flexion or some other motions as well as addressing the associated labral and chondral pathologeny. Surgical treatment of CI, for example, includes removal of the excess bone from the femoral neck, to recreate the anatomic sphericity of the femoral head and to reduce the prominence of the femoral neck which abuts the anterior labrum and acetabulum. The excess bone on the proximal femur can be removed by a surgeon using surgical tools such as a high speed bur or an arthroscopic shaver. To plan for the surgical repair of the target pathological bone, the deformity of the bone, such as the prominent femoral head-neck region in CI, needs to be identified and defined. Deformity can be identified on output from a magnetic resonance (MR) arthrogram or a computed tomography (CT) scan. In many cases, a surgeon is required to mentally map the deformity area to the operative bone. Computer-aided tools can be used in more advanced procedures to define the bone removal volume, either by looking at the simulated hip motion and the resulting zones of impingement, or by fitting an idealized axisymmetric surface to the femoral neck. These methods, however, can be difficult to operate and may suffer from lack of reliability and certainty. For example, the impingement area can have reduced visualization and access, particularly during minimally invasive surgery and arthroscopic techniques. Identifying the impingement zones can be problematic due to, for example, the flexion of th