Methods, systems, and devices for designing and manufacturing a spinal rod

Abstract

According to some embodiments, the process includes the steps of: a) taking a sagittal preoperative x-ray of the vertebral column of the patient to be treated, extending from the cervical vertebrae to the femoral heads; b) on that x-ray, identifying points on S1, S2, T12 et C7; c) depicting, on the said x-ray, curved segments beginning at the center of the plate of Si et going to the center of the plate of C7; e) identifying, on that x-ray, the correction(s) to be made to the vertebral column, including the identification of posterior osteotomies to make; f) pivoting portions of said x-ray relative to other portions of that x-ray, according to osteotomies to be made; g) performing, on said x-ray, a displacement of the sagittal curvature segment extending over the vertebral segment to be corrected; h) from a straight vertebral rod (TV), producing the curvature of that rod according to the shape of said sagittal curvature segment in said displacement position.

Claims

1. A patient-specific implantable spinal rod, the patient-specific implantable spinal rod comprising: a diameter; a length; and a curvature, wherein the curvature is determined by: accessing one or more modified representations of a pre-operative spine of a patient, wherein the one or more modified representations of the pre-operative spine of the patient comprises a first curved segment above a reference point and a second curved segment below the reference point, wherein a first curvature of the first curved segment is different from a second curvature of the second curved segment; analyzing the one or more modified representations of the pre-operative spine of the patient to determine the first curvature of the first curved segment and the second curvature of the second curved segment; and determining one or more specifications of the curvature of the patient-specific implantable spinal rod based at least in part on the determined first curvature of the first curved segment and the second curvature of the second curved segment.

2. The patient-specific implantable spinal rod of claim 1, wherein the first curved segment comprises sacral vertebrae of the vertebral column.

3. The patient-specific implantable spinal rod of claim 1, wherein the first curved segment comprises one or more vertebrae between L1 to L5.

4. The patient-specific implantable spinal rod of claim 1, wherein the one or more preoperative representations of the vertebral column of the patient comprises one or more preoperative x-ray images.

5. The patient-specific implantable spinal rod of claim 4, wherein the one or more preoperative x-ray images comprises one or more sagittal x-ray images.

6. The patient-specific implantable spinal rod of claim 4, wherein the one or more preoperative x-ray images comprises one or more sagittal x-ray images and one or more frontal x-ray images.

7. The patient-specific implantable spinal rod of claim 1, wherein the one or more representations of the pre-operative spine of the patient are modified by pivoting one or more portions of the one or more representations of the pre-operative spine of the patient.

8. A method of manufacturing a patient-specific implantable spinal rod, the method comprising: accessing one or more preoperative representations of a vertebral column of a patient, wherein the one or more preoperative representations show a correction to be made to the vertebral column of the patient; determining curvatures of a first curved segment and a second curved segment of the vertebral column represented in the one or more preoperative representations, wherein the first curved segment of the vertebral column comprises a portion of the vertebral column below a reference point and the second curved segment of the vertebral column comprises a portion of the vertebral above the reference point, wherein the second curved segment comprises a different curvature than the first curved segment; generating a patient-specific implantable spinal rod specification based at least in part on the calculated curvatures of the first and second curved segments of the vertebral column; transmitting the generated patient-specific implantable spinal rod specification to a manufacturing system to manufacture the patient-specific implantable spinal rod; and producing the patient-specific implantable spinal rod based at least in part on the transmitted patient-specific implantable spinal rod specification.

9. The method of claim 8, wherein the first curved segment comprises sacral vertebrae of the vertebral column.

10. The method of claim 8, wherein the first curved segment comprises one or more vertebrae between L1 to L5.

11. The method of claim 8, wherein the one or more preoperative representations of the vertebral column of the patient comprises one or more preoperative x-ray images.

12. The method of claim 11, wherein the one or more preoperative x-ray images comprises one or more sagittal x-ray images.

13. The method of claim 11, wherein the one or more preoperative x-ray images comprises one or more sagittal x-ray images and one or more frontal x-ray images.

14. The method of claim 8, wherein the one or more representations of the pre-operative spine of the patient are modified by pivoting one or more portions of the one or more representations of the pre-operative spine of the patient.

15. A method of correcting a spine of a patient, the method comprising: obtaining a patient-specific implantable spinal rod of the patient, wherein the patient-specific implantable spinal rod is produced by: accessing one or more preoperative representations of a vertebral column of a patient, wherein the one or more preoperative representations show a correction to be made to the vertebral column of the patient; determining curvatures of a first curved segment and a second curved segment of the vertebral column represented in the one or more preoperative representations, wherein the first curved segment of the vertebral column comprises a portion of the vertebral column below a reference point and the second curved segment of the vertebral column comprises a portion of the vertebral above the reference point, wherein the second curved segment comprises a different curvature than the first curved segment; generating a patient-specific implantable spinal rod specification based at least in part on the calculated curvatures of the first and second curved segments of the vertebral column; transmitting the generated patient-specific implantable spinal rod specification to a manufacturing system to manufacture the patient-specific implantable spinal rod; producing the patient-specific implantable spinal rod based at least in part on the transmitted patient-specific implantable spinal rod specification; and implanting the produced patient-specific implantable spinal rod in the patient.

16. The method of claim 15, wherein the first curved segment comprises sacral vertebrae of the vertebral column.

17. The method of claim 15, wherein the first curved segment comprises one or more vertebrae between L1 to L5.

18. The method of claim 15, wherein the one or more preoperative representations of the vertebral column of the patient comprises one or more preoperative x-ray images.

19. The method of claim 18, wherein the one or more preoperative x-ray images comprises one or more sagittal x-ray images.

20. The method of claim 15, wherein the one or more representations of the pre-operative spine of the patient are modified by pivoting one or more portions of the one or more representations of the pre-operative spine of the patient.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a diagrammatically view of the base of a vertebral column;

(2) FIG. 2 is a very diagrammatic view of a vertebral column CV as shown on an x-ray, referencing the lumbar lordosis LL, the names of the vertebrae S2-L5 in question, the femoral heads TF, a point situated at the center of the plate of S1, and the pelvic criteria SS, PV, PI explained above in reference to FIG. 1;

(3) FIG. 3 is a view similar to FIG. 2, in which the center point of the second vertebra of the sacrum, called S2, is shown;

(4) FIG. 4 is a view similar to FIG. 3, in which the center point of the lower plate of the twelfth dorsal vertebra, called T12, is shown;

(5) FIG. 5 is a view similar to FIG. 4, in which the center point of the lower plate of the seventh cervical vertebra, called C7, is shown;

(6) FIG. 6 is a view similar to FIG. 5, in which a first curved segment SC1 and a second curved segment SC2 are further shown;

(7) FIG. 7 is a view similar to FIG. 6, in which osteotomies O1, O2 to be done on the upper plates, posterior sides, of vertebrae L4 and L5 (fourth and fifth lumbar vertebra) are also shown;

(8) FIG. 8 is a view similar to FIG. 7, showing two portions P1, P2 of the x-ray, delimited by frames, that have been pivoted relative to the respective positions that those same portions occupy in FIG. 7, in the counterclockwise direction regarding P1 and the clockwise direction regarding P2; these new positions are corrected positions of the vertebral column CV, made possible by the corrected lumbar curvature made possible by the osteotomies O1, O2 to be done; in order to view the correction made, the uncorrected vertebral column, as shown in FIG. 7, is superimposed on the corrected vertebral column shown by FIG. 8, that uncorrected vertebral column being shown in thin and broken lines;

(9) FIG. 9 is a view similar to FIG. 8, showing, in broken lines, the respective distances DL5 to DT12 which, for each of vertebrae L5 to T12, go from the center of the body of the vertebra to the posterior face of a pedicle of that vertebra;

(10) FIG. 10 is a view similar to FIG. 9, showing a sagittal curvature segment SC that corresponds to the curvature to be given to a vertebral rod to produce the desired correction of the vertebral column;

(11) FIG. 11 is, on the left side of that figure, a view of a plane of the curved vertebral rod to be obtained, established from said sagittal curvature segment SC, and, on the right side of that figure, a view of the curved vertebral rod TV, obtained from that plane P;

(12) FIG. 12 is, on the left, a partial view of a frontal x-ray RF of the vertebral column of the patient to be treated, and, on the right, a side view of said sagittal curvature segment SC, on which reference points PC are identified; and

(13) FIG. 13 is a view of a recalculated sagittal curvature segment SCR, obtained following stretching of a portion of the sagittal curvature segment SC.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(14) FIGS. 2 to 11 illustrate a method making it possible to produce the ideal curvature of a vertebral rod TV that is a part of a vertebral osteosynthesis equipment, designed to correct a patient's vertebral column by performing a correction of that vertebral column. This method comprises the following successive steps:

(15) FIG. 2: taking a sagittal preoperative x-ray RS of the vertebral column of the patient to be treated, extending from the cervical vertebrae to the femoral heads, and identifying, on that x-ray RS:

(16) LL: the vertebral segment to be treated;

(17) L1, L2, L3, L4, L5, S1, S2, T12, C7: the first, second, third, fourth and fifth lumbar vertebrae, the first and second vertebrae of the sacrum, the twelfth dorsal vertebra and the seventh cervical vertebra, respectively;

(18) SS, PV, PI: the aforementioned pelvic criteria;

(19) TF: the femoral heads, shown by a circle in the figure;

(20) also identifying, by a dot, the center of the plate of S1.

(21) FIG. 3: identifying, on the x-ray RS, the center of the plate of S2 using a dot.

(22) FIG. 4: identifying, on the x-ray RS, the center of the lower plate of T12 using a dot.

(23) FIG. 5: identifying, on the x-ray RS, the center of the lower plate of C7 using a dot.

(24) FIG. 6: depicting, on said x-ray RS, said first and second curved segments SC1, SC2; the first curved segment SC1 begins at the center of the plate of S1, tangent to the segment going from the center of S2 to the center of the plate of S1, passes through the centers of the bodies of the vertebrae of segment L5-L1 and ends at the center of the lower plate of T12; the second curved segment SC2 is tangent to the first curved segment SC1 at the center of the lower plate of T12, passes through the centers of the bodies of the vertebrae of segment T11-C6 and goes to the center of the lower plate of C7.

(25) FIG. 7: identifying, on the x-ray RS, the correction(s) of the vertebral column that must be performed, and in particular identifying the osteotomies O1, O2 to be done in order to obtain a corrected lumbar curvature; in the illustrated example, the determination is made to perform an osteotomy O1 of 10.degree. on the upper plate of L4 and an osteotomy O2 of 10.degree. on the upper plate of L5.

(26) FIG. 8: pivoting the portions P1 and P2 of the x-ray RS relative to the rest of that x-ray RS, based on the osteotomies O1, O2 to be done; in the illustrated example, the portion P1 pivots by 10.degree. in the counterclockwise direction relative to the portion of the x-ray on which L4 is located (angulation made possible by the osteotomy O2) and the portion P2 pivots by 10.degree. in the clockwise direction relative to the portion of the x-ray on which L4 is located (angulation made possible by the osteotomy O1). Said first and second curved segments SC1 and SC2 are then recalculated based on the correction(s) made and are shown on the x-ray RS.

(27) FIG. 9: the length of the vertebral segment to be corrected is determined (in the case at hand, L5-T12), which makes it possible to determine the length of each vertebral rod TV to be implanted; for each vertebra of that segment, the respective distances DL5 to DT12 are determined from the center of the body of the vertebrae to the posterior face of a pedicle of that vertebra, i.e., the entry face of a pedicle screw in the pedicle; these distances are either read on the x-ray RS, or are read in a previously established databank, containing, for each vertebra, the mean value, established statistically, of that distance for the type of patient in question, in particular based on the age, gender and size of that patient;

(28) FIG. 10: a displacement of the curved segment is then done, on the x-ray RS, over the respective distances DL5 to DT12, and the curvature of that segment is recalculated in the displacement position.

(29) FIG. 11: after the diameter of the vertebral rod TV to be used has been determined based on the patient in question, a plane P of the curvature of that rod is established, from which the rod TV is made, by curvature from a straight vertebral rod, in particular by cold bending.

(30) FIGS. 12 and 13 show the following steps that the method may comprise:

(31) FIG. 12:

(32) also taking a frontal x-ray RF of the vertebral column CV of the patient to be treated;

(33) on that x-ray RF, identifying one or more potential portions of that vertebral column CV that are curved in the frontal plane, and which must therefore be corrected, and a reference point PRD at the center of the body of the vertebra on which the curved portion begins and a reference point PRF at the center of the body of the vertebra on which the curved portion ends;

(34) measuring the length of the curved segment extending between those reference points PRD, PRF;

(35) identifying, on the aforementioned sagittal x-ray RS, these same reference points PRD, PRF on these same vertebrae, and identifying the corresponding points PC on said sagittal curvature segment SC; and

(36) performing homothetic stretching of the portion of said sagittal curvature segment SC extending between these corresponding points PC, so as to give that portion a length identical to that separating the aforementioned reference points PRD, PRF.

(37) FIG. 13: a recalculated sagittal curvature segment SCR is thus obtained, taking the elongation of the vertebral column resulting from the correction of that column in the frontal plane into account.

(38) The method according to the invention thus has the decisive advantage of making it possible to produce the ideal curvature of a rod for vertebral osteosynthesis equipment designed to correct a patient's vertebral column.