Patient-specific surgical methods and instrumentation
A method may be used to correct a condition present in a patient. The method may include obtaining a first bone model of a first bone of one or more bones of the patient's foot, and using at least the first bone model to generate a cutting guide model. The cutting guide model may define a first bone engagement surface shaped to match a first contour on the first bone, and a first guide feature that, with the first bone engagement surface overlying the first contour, is positioned to guide resection of the one or more bones as part of a surgical osteotomy for correcting the condition. The surgical procedure may be selected from a first group consisting of a bunion correction osteotomy, an Evans calcaneal osteotomy, and a medializing calcaneal osteotomy. The first bone may be selected from a second group consisting a metatarsus, a cuneiform, and a calcaneus.
1. A method for correcting a bunion present in a patient's foot, the method comprising:
obtaining a first bone model of a cuneiform of the patient's foot;
obtaining a second bone model of a metatarsus of the patient's foot;
virtually repositioning the second bone model relative to the first bone model to simulate
reorientation of the metatarsus relative to the cuneiform to correct the bunion; and
using at least the first bone model relative to the repositioned second bone model to generate a cutting guide model defining:
a first bone engagement surface shaped to match a first contour on the cuneiform;
a second bone engagement surface shaped to match a second contour of the metatarsus; and
a first guide feature that, with the first bone engagement surface overlying the first contour, is positioned to guide resection of at least one of the cuneiform and the metatarsus as part of a bunion correction osteotomy for correcting the bunion.
2. The method of claim 1 , wherein:
the first guide feature is positioned to guide resection of the cuneiform; and
the cutting guide model further defines:
a second guide feature that, with the second bone engagement surface overlying the second contour, is positioned to guide resection of the metatarsus.
3. The method of claim 2 , wherein the cutting guide model further comprises:
a first end having the first bone engagement surface;
a second end having the second bone engagement surface;
a first bone attachment feature positioned to secure the first end to the cuneiform; and
a second bone attachment feature positioned to secure the second end to the metatarsus.
4. The method of claim 3 , further comprising:
using the cutting guide model to fabricate a cutting guide having the first bone engagement surface, the second bone engagement surface, the first bone attachment feature, the second bone attachment feature, the first guide feature, and the second guide feature.
5. The method of claim 4 , further comprising:
placing the cutting guide such that the first bone engagement surface overlies the first contour and the second bone engagement surface overlies the second contour;
securing the first bone attachment feature to the cuneiform;
securing the second bone attachment feature to the metatarsus;
with the first guide feature, guiding motion of a cutter to resect the cuneiform; and
with the second guide feature, guiding motion of a cutter to resect the metatarsus.
6. The method of claim 5 , further comprising:
reorienting the metatarsus relative to the cuneiform; and
after reorienting the metatarsus relative to the cuneiform, promoting fusion between the cuneiform and the metatarsus.
7. The method of claim 1 , wherein:
obtaining the first bone model comprises obtaining CT scan data of the cuneiform; and
using the first bone model to generate the cutting guide model comprises:
converting the CT scan data to a CAD models;
using the CAD model to obtain the first contour; and
using the first contour to generate the first bone engagement surface of the cutting guide model.
8. The method of claim 1 , further comprising using at least the first bone model to generate an implant model defining a first bone-facing surface comprising a first shape that matches a first profile of a first resected surface with a cutting guide fabricated using the cutting guide model.
9. The method of claim 8 , wherein the implant model further comprises a second bone-facing surface comprising a second shape that matches a second profile of a second resected surface of the cuneiform or the metatarsus after resection with the cutting guide.
10. The method of claim 9 , further comprising:
using the cutting guide model to fabricate a cutting guide having the first bone engagement surface and first guide feature;
using the implant model to fabricate an implant having the first bone-facing surface and the second bone-facing surface;
placing the cutting guide such that the first bone engagement surface overlies the first contour;
with at least the first guide feature, guiding motion of a cutter to resect at least one of the cuneiform or the metatarsus to define the first resected surface and the second resected surface; and
placing the implant between the first resected surface and the second resected surface such that the first shape is aligned with the first profile and the second shape is aligned with the second profile.