# Patent

## Title
Patient-specific sacroiliac and pedicle guides

## Abstract

An orthopedic device includes a first patient-specific element having a first patient-specific surface preoperatively configured to mate and conform to a first anatomic portion of a specific patient based on medical scans of the patient. The orthopedic device includes a second patient-specific element having a second patient-specific surface preoperatively configured to mate and conform to a second anatomic portion of a specific patient based on medical scans of the patient. An arcuate bridge couples the first and second patient-specific portions. The arcuate bridge is configured to provide clearance the patient's anatomy between the first and second anatomic portions.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 13/221,968 filed on Aug. 31, 2011. This application claims priority to U.S. Patent Application No. 61/720,588 filed on Oct. 31, 2012. The entire disclosures of each of the above applications are incorporated herein by reference.


FIELD
The present teachings provide various patient-specific alignment guides for the pelvic and spinal fixation, including sacroiliac and pedicle guides.
INTRODUCTION
The present teachings provide various patient-specific alignment guides for sacro-pelvic, sacroiliac and/or posterior iliac fixation and for spinal pedicle fixation. The patient-specific alignment guides facilitate more accurate placement of bone screws and other fixation devices that are used in various spinal fixation systems. The patient-specific alignment guides are designed and constructed preoperatively based on three-dimensional digital images of portions of the patient's pelvis and spine, including the ilium and the sacrum. The digital images of the patient's anatomy can be reconstructed from medical scans of the patient using commercially available CAD (Computer Aided Design) and/or other imaging software.
SUMMARY
The present teachings provide orthopedic devices that include orthopedic devices including patient-specific alignment guides for various lumbopelvic and spinal fixation procedures.
In some embodiments, the present teachings provide an orthopedic device that includes a first patient-specific element having a first patient-specific surface preoperatively configured to mate and conform to a first anatomic portion of a specific patient based on medical scans of the patient. The orthopedic device includes a second patient-specific element having a second patient-specific surface preoperatively configured to mate and conform to a second anatomic portion of a specific patient based on medical scans of the patient. An arcuate bridge couples the first and second patient-specific portions. The arcuate bridge is configured to provide clearance for the patient's anatomy between the first and second anatomic portions.
In some embodiments, the first and second patient specific surfaces of the orthopedic device include portions configured to mate with corresponding first and second transverse processes of a vertebra of the patient.
In some embodiments, the first and second patient specific surfaces of the orthopedic device include portions configured to mate with corresponding first and second iliac crests of the patient.
In some embodiments, the orthopedic device includes a patient-specific alignment guide configured for a first vertebra of a spinal column of a specific patient. The alignment guide includes a U-shaped guide body having first and second legs joined at a distal portion. The distal portion has a patient-specific surface preoperatively configured to mate with a corresponding surface of a spinous process of the first vertebra. The first and second legs of the guide body have corresponding first and second hooks configured to mate with corresponding portions of first and second transverse processes of the first vertebra.
In some embodiments, the orthopedic device includes a patient-specific alignment guide configured for a first vertebra of a spinal column of a specific patient. The alignment guide includes a U-shaped guide body having first and second legs joined at a distal portion. The distal portion has a patient-specific surface preoperatively configured to mate with a corresponding surface of a spinous process of the first vertebra. The first and second legs have corresponding first and second hooks configured to mate with corresponding portions of first and second transverse processes of the first vertebra. The orthopedic device can also include an arcuate bridge connecting the first and second legs. The arcuate bridge includes a pressure pad for applying pressure for securing the guide onto the vertebrae,
In some embodiments, the patient-specific alignment guide includes a patient-specific portion and a guiding element having a through opening. The patient-specific portion has a patient-specific surface preoperatively configured to nestingly mate as a negative of a portion of an iliac crest of a pelvis of a specific patient and mate to the iliac crest only in one position. The guiding element has a preoperatively configured orientation and location relative to the patient-specific portion for preparing a bore in the bone of the patient to direct a bone screw at the preoperatively configured orientation and location for sacroiliac fixation.
In some embodiments, the patient-specific alignment guide includes first and second patient-specific portions coupled by an arcuate bridge. The first patient-specific portion has a patient-specific surface preoperatively configured to nestingly mate to a portion of a first iliac crest of a pelvis of a specific patient and mate to the first iliac crest only in one position. The second patient-specific portion is similarly constructed for a second iliac crest of the patient. The bridge is configured to span a posterior contour of the pelvis of the patient. The patient-specific alignment guide can include first and second iliac guiding elements coupled to the corresponding first and second patient-specific portions, and first and second sacral guiding elements coupled to the bridge. Each of the first and second iliac and sacral guiding elements has a through opening and a preoperatively configured orientation and location relative to one of the first and second patient-specific portions for preparing a corresponding bore in the bone of the patient to direct a corresponding bone screw for sacroiliac fixation.
The present teachings also provide a method for lumbopelvic fixation. The method includes providing a convertible patient-specific alignment guide for a patient's pelvis and intraoperatively selecting one of unilateral fixation, iliac fixation, sacral fixation and bilateral sacroiliac fixation procedure for the patient. The convertible patient-specific alignment guide is reconfigured intraoperatively to a corresponding patient-specific alignment guide for the selected procedure. The convertible patient-specific alignment guide includes first and second patient-specific portions coupled by a bridge.
Further areas of applicability of the present teachings will become apparent from the description provided hereinafter. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present teachings.



BRIEF DESCRIPTION OF THE DRAWINGS
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
FIG. 1 is an environmental view of a portion of a spinal rod system;
FIG. 2 is an environmental view of a portion of another spinal rod system;
FIG. 3 is a detail of a multi-axial screw assembly of the spinal rod system shown in FIG. 2;
FIG. 4 is a perspective view of a patient-specific universal alignment guide according to the present teachings;
FIG. 4A is a detail of another embodiment of the patient-specific universal alignment guide of FIG. 4;
FIG. 4B is a detail of another embodiment of the patient-specific universal alignment guide of FIG. 4;
FIG. 4C is a perspective view of a drill guide according to the present teachings;
FIG. 4D is a side view of the drill guide of FIG. 4C;
FIG. 4E is a detail of the patient-specific universal alignment guide of FIG. 4 showing an exemplary marking;
FIG. 5 is an environmental view of the universal alignment guide of FIG. 4;
FIG. 5A is an environmental view of another universal alignment guide according to the present teachings;
FIG. 6 is an environmental view of a patient-specific iliac alignment guide according to the present teachings;
FIG. 6A is a perspective view of a fixation pin shown in FIG. 6;
FIG. 7 is an environmental view of a patient-specific sacral alignment guide according to the present teachings;
FIG. 8 is an environmental view of a unilateral iliac alignment guide according to the present teachings;
FIG. 9 is an environmental view of a patient's pelvis showing representative bores drilled into the pelvis using the patient-specific alignment guides of FIG. 5, 5A, 7 or 8;
FIG. 10 is an environmental view of a spinal rod system showing sacral and iliac screws positioned with patient-specific alignment guides according to the present teachings;
FIG. 11 is an environmental perspective view showing placement of sacral and iliac screws according to the present teachings;
FIG. 12 is another environmental perspective view showing placement of sacral and iliac screws according to the present teachings;
FIG. 13 is another environmental perspective view showing placement of sacral and iliac screws according to the present teachings;
FIG. 14 is an environmental view of a patient-specific pedicle alignment guide according to the present teachings;
FIG. 15 illustrates a trajectory of a pedicle screw for use with the patient-specific pedicle alignment guide on a CT image of a superior view of a vertebral body of the patient according to the present teachings;
FIG. 16 illustrates a trajectory of a pedicle screw for use with the patient-specific pedicle alignment guide on and a center of the pedicle in a CT image of a side view of a vertebral body of the patient according to the present teachings;
FIG. 17 is an environmental view illustrating the trajectory and entry of pedicle screws through a patient-specific pedicle alignment guide according to the present teachings;
FIG. 18 is another environmental view illustrating the trajectory and entry of pedicle screws through the patient-specific pedicle alignment guide of FIG. 17;
FIG. 19 is a bottom perspective view of an embodiment of a patient-specific pedicle alignment guide according to the present teachings;
FIG. 20 a top perspective view of the patient-specific pedicle alignment guide of FIG. 19;
FIG. 21 is an environmental lateral perspective view of an embodiment of a patient-specific pedicle alignment guide according to the present teachings;
FIG. 22 is an environmental posterior perspective view of the patient-specific pedicle alignment guide of FIG. 21;
FIG. 23 is a posterior perspective view of the patient-specific pedicle alignment guide of FIG. 21 shown on a vertebra;
FIG. 24 is a lateral perspective view of the patient-specific pedicle alignment guide of FIG. 21 shown on a vertebra;
FIG. 25 an environmental lateral perspective view of an embodiment of the patient-specific pedicle alignment guide of FIG. 21 shown pedicle screw trajectories; and
FIG. 26 an environmental posterior perspective view of an embodiment of the patient-specific pedicle alignment guide of FIG. 21 shown with pedicle screw trajectories.



Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION
The following description is merely exemplary in nature and is in no way intended to limit the present teachings, applications, or uses. For example, although some of the present teachings are illustrated for sacroiliac fixation, the present teachings can be used for any other lumbopelvic procedure or lumbar and/or pelvic correction including trauma, deformation or disease.
The present teachings provide various patient-specific alignment guides or lumbopelvic fixation of the pelvic area and/or transpedicular fixation of the spine. FIGS. 1-13 are described in relation to sacro-pelvic, sacroiliac and/or posterior iliac fixation. FIGS. 14-26 are described in relation to spinal transpedicular fixation. The patient-specific alignment guides can facilitate and improve the accuracy of the placement of bone screws and other fixation devices that are used in various spinal fixation systems, such as, for example, thoracic, lumbar and lumbopelvic fixation systems.
Referring to lumbopelvic fixation, FIGS. 1-13, the corresponding patient-specific alignment guides of the present teachings are designed to guide and facilitate lumbopelvic fixation and help mitigate bone screw breaches of bone or neurovascular injury that can sometimes happen during unguided implantation of a lumbopelvic fixation system. Further, unguided implantation can be complicated by the characteristic three-dimensional geometry of the sacroiliac anatomy and/or the difficulty in directing bone screws toward strong bone anchorage, especially in the presence of cortical deficiencies, such as those that can be caused by previous autograft harvest from the posterior superior iliac spine (PSIS). Additionally, the receiver element of a bone screw assembly that is configured to receive a rod of a lumbopelvic fixation system and also support a corresponding bone screw can further complicate the placement of the bone screws connected to the corresponding receiver elements. The patient-specific alignment guides of the present teachings are preoperatively configured to alleviate or reduce some of these complications for each specific patient.
Similarly, referring to spinal transpedicular fixation, FIGS. 4-26, the corresponding patient-specific alignment guides of the present teachings are designed to Determine and guide optimal path for pedicle screw insertion for each specific patient and accurately align and guide in vivo the intended path via a corresponding patient-specific pedicle alignment guide.
The patient-specific alignment guides are designed and constructed preoperatively based on three-dimensional digital images of portions of the patient's pelvis and spine, including the ilium, iliac wings, iliac crests and the sacrum, for lumbopelvic alignment guides, and spinal vertebrae and pedicles for the pedicle alignment guides. The three-dimensional digital images of the patient's anatomy can be reconstructed preoperatively from MRI, CT, ultrasound, X-ray, or other imaging and medical scans of the patient's anatomy using computer-assisted image methods. Various CAD programs and/or software can be utilized for three-dimensional image reconstruction, such as, for example, software commercially available by Materialise USA, Plymouth, Mich.
Various pre-operative planning procedures and patient-specific alignment guides are described in commonly assigned and U.S. patent application Ser. No. 11/756,057, filed May 31, 2007, now U.S. Patent Publication No. 2007/0288030; U.S. patent application Ser. No. 12/025,414, filed Feb. 4, 2008, now U.S. Patent Publication No. 2008/0114370; U.S. patent application Ser. No. 12/103,824, filed Apr. 16, 2008, now U.S. Patent Publication No. 2008/0257363; U.S. patent application Ser. No. 12/371,096, filed Feb. 13, 2009, now U.S. Patent Publication No. 2009/0151736; U.S. patent application Ser. No. 12/483,807, filed Jun. 12, 2009, now U.S. Patent Publication No. 2009/0254367; U.S. patent application Ser. No. 12/872,663, filed Aug. 31, 2010, now U.S. Patent Publication No. 2010/0324692; U.S. patent application Ser. No. 12/973,214, filed Dec. 20, 2010, now U.S. Patent Publication No. 2011/0092804; and, U.S. patent application Ser. No. 12/978,069, filed Dec. 23, 2010, now U.S. Patent Publication No. 2011/0093086. The disclosures of the above applications are incorporated herein by reference.
In the preoperative planning stage for lumbopelvic fixation, a preoperative surgical plan is formulated for a specific patient with interactive input from the patient's surgeon or other medical professional. Imaging data of the relevant anatomy of a patient can be obtained at a medical facility or doctor's office, using any of the medical imaging methods described above. The imaging data can include, for example, various medical scans of a relevant joint portion or other relevant portion of the patient's anatomy, as needed for the particular surgical procedure. The imaging data thus obtained and other associated information can be used to construct a three-dimensional computer (digital) image of a relevant portion of the anatomy of the patient, such as, in the present application, portions of the patient's pelvis and spine, including the sacral and iliac regions, and or the thoracic regions of the spine. The three-dimensional digital image of the patient's anatomy can be used to formulate a preoperative surgical plan specific to the patient. The preoperative surgical plan can include the design and construction of implants, patient-specific alignment guides and other instruments according to selected methods of surgical preparation and implantation. The preoperative surgical plan can also include planning for the location and orientation of bone modifications and/or resections and trajectory paths for various implant components, including, for example bone screws.
Generally, the patient-specific alignment guides of the present teachings are configured to match portions of the iliac and/or sacral anatomy or spinal/thoracic anatomy of a specific patient and are generally designed and configured using computer modeling based on the reconstructed three-dimensional digital image of the patient's corresponding anatomy, as discussed above. The patient-specific alignment guides have a patient-specific anatomy-engaging surface that is configured as a mirror or negative or complementary surface that can conformingly contact and match a corresponding bone surface of the patient (with or without cartilage or other soft tissue). In this respect, a patient-specific alignment guide can register to and nestingly mate with the corresponding bone surface, such as, for example, a portion of the iliac crest, or the spinous and transverse processes of the vertebral bodies of the specific patient in only one position. The patient-specific alignment guides of the present teachings can be configured for use in any surgical procedure, such as open, mini-open and minimally invasive procedure.
The three-dimensional model of the patient's anatomy can be viewed on a computer display or other electronic screen and can also be reproduced as a hard copy on film or other medium and viewed by direct or indirect or backlight illumination. The model can be sized for viewing on any appropriate screen size and may be cropped, rotated, etc., as selected by the individual (e.g., the surgeon) viewing the screen.
The patient-specific alignment guides can be manufactured by rapid prototyping methods, such as stereolithography or other similar methods, or by CNC milling, or other automated or computer-controlled machining or robotic methods. The patient-specific alignment guides can be manufactured from any biocompatible materials, including metals, polymers and combinations thereof. The patient-specific alignment guides, the implants for the surgical procedure and, optionally, other disposable instruments can be sterilized, packaged and forwarded to the surgeon or the surgeon's medical facility for the surgical procedure.
As a brief overview, and referring to FIGS. 1-13, prior art spinal fixation systems are briefly described in reference to FIGS. 1-3. Various embodiments of patient-specific alignment guides are described in reference to FIGS. 4-8. For example, FIG. 6 illustrates a patient-specific “iliac” guide 100A for inserting fixation screws starting from and into the ilium of the patient, according to the present teachings. FIG. 7 illustrates a patient-specific “sacral” guide 100B for inserting fixation screws from the sacrum and into the ilium, according to the present teachings. FIGS. 4, 5 and 5A illustrate “universal” patient-specific guides 100, 100′ for inserting bilaterally or unilaterally fixation screws from and into the ilium and/or from the sacrum and into the ilium according to the present teachings. FIG. 8 illustrates a patient-specific unilateral iliac guide 100C for inserting fixation screws into the left ilium according to the present teachings. FIG. 9 illustrates screw bores prepared in the bone using an alignment guide of the present teachings and shown after the alignment guide is removed. Post implantation details of the lumbopelvic fixation system implanted using the bores pre-drilled with the alignment guides of the present teachings are shown in FIGS. 8-13.
Referring to FIGS. 1-3, portions of prior art spinal fixation systems (or rod systems) are illustrated. Various spinal and/or lumbopelvic fixation systems are commercially available from Biomet Manufacturing Corp., Warsaw, Ind., and include, for example, the Polaris® fixation system and the Array® fixation system. An exemplary spinal fixation system 50 can include elongated fixation members or rods 52 that can be attached to the patient's anatomy with bone screw assemblies 60 inserted into thoracic pedicles, lumbar pedicles 45, sacrum 40 and/or iliac wings 30 or iliac crest 32 of a patient's pelvis depending on the surgical technique and the corrective procedure selected for the patient. The bone screw assembly 60 can include a bone screw 62 with a bone anchoring portion inserted into the bone, a U-shaped (“tulip”) receiver 64, and a securing cap 66. The receiver 64 is configured to receive or support the head of the bone screw 62 and optionally allow multi-axial pivoting of the bone screw 62. The receiver 64 is also configured to transversely hold the rod 52. The securing cap 66 is received and/or engaged to the receiver 64 and locks the rod 52 and the bone screw 62. In other embodiments, the bone screw assembly 60 can include fixed, rather than polyaxial, bone screws.
With continued reference to FIGS. 1-3, cross-connectors 70 between two rods 52 can be used to provide additional stability to the spinal fixation system 50 along the spine. Further, lateral connectors 76 can be used to provide iliac fixation and extend the spinal fixation system 50 over the iliac wings, as shown in FIG. 1. The lateral connector 76 shown in FIG. 1 includes, for example, a receiver portion 75 coupled to the rod 52 and an elongated shaft 78 coupled to a bone screw assembly 60 that is positioned through the iliac crest 32. Exemplary embodiments of the spinal fixation system 50 and associated instruments and implants, including the bone screw assembly 60 with the optional cross connectors 70 and lateral connectors 76 are commercially available from Biomet Manufacturing Corp., Warsaw, Ind. It will be appreciated, however, that other spinal fixation systems can be used according to the present teachings including, for example, the spinal fixation systems, bone screw assemblies, cross connectors and lateral connectors described in U.S. Pat. Nos. 7,294,129, 6,302,888, 6,616,668 and 7,699,876, the disclosures of which are incorporated herein by reference.
Referring to FIGS. 4-5A, 9 and 10, two embodiments of a universal patient-specific sacroiliac alignment guide 100, 100′ (“the universal guide” for short) are illustrated. The universal guide 100, 100′ is preoperatively configured to guide the drilling of one or more “iliac” (starting at the iliac wing or iliac crest) bores 150, 152 and one or more “sacral” (starting at the sacrum) bores 154 (see FIG. 9) to implant corresponding iliac and sacral bone screws 61, 63, 65 for a spinal fixation system 50 (see FIG. 10). As can be seen in FIG. 9, the iliac bores 150, 152 are initiated from an iliac crest 32 and are directed into an iliac wing 30. The sacral bores 154 initiated from the sacrum 40 and are also directed into the iliac wing 30 through a corresponding sacroiliac joint. The two embodiments of the universal guide 100, 100′ have many similar elements and will be commonly described, except as noted to highlight any differences. Each universal guide 100, 100′ can include first and second patient-specific portions 102 (right 102R, left 102L) that can be either integrally (monolithically) or modularly (removably) connected to one another by an elongated curved or arcuate connector or bridge 104. The bridge 104 can include a tab portion 106 with a through hole 108 for receiving a locating pin 140 (K-wire or other type of pin) referencing the first sacral process (51) of the spine, as shown in FIGS. 5 and 9. The locating pin 140 can be used to confirm the accurate placement of the universal guide 100, 100′ by intraoperatively trialed to confirm contact with the S1 sacral process. The locating pin 140 can also be used for other anatomic landmarks, such as one or more sacral or spinous processes. The arcuate shape of the bridge 104 generally follows the contour of the posterior surface of the pelvis and can facilitate an effortless placement of the universal guide 100, 100′ on the specified anatomy. The bridge 104 can also function as a handle for holding or guiding the universal guide 100, 100′ on the pelvis. The bridge 104 can be removably coupled to each patient-specific portion 102 by a taper-to-taper or other releasable connection, as shown in the exemplary illustration of FIG. 4A.
With continued reference to FIGS. 4-5A, 9 and 10, each patient-specific portion 102 is preoperatively configured from a three-dimensional image of the pelvis of the patient that is reconstructed from medical scans of the patient, as discussed above. Specifically, the patient-specific portion 102 has a patient-specific surface 103 configured as a negative or mirror of a portion of the iliac crest 32 and, optionally, adjacent areas. The patient-specific surface 103 tracks the unique anatomy of the specific patient's iliac crest 32 that provides natural referencing landmarks. Accordingly, the patient-specific portion 102 can be positioned intraoperatively with accuracy, and without our intraoperative guidance, in a preoperative determined single location of the iliac crest 32. The patient-specific portion 102 nests and nestingly mates to the corresponding iliac crest 32, as shown in FIGS. 5 and 5A. In some embodiments, the patient-specific portion 102 can snap onto the corresponding iliac crest 32.
Each patient-specific portion 102 includes one or more “iliac” guiding elements 122, 124 with corresponding openings 123, 125 passing through the patient-specific portion 102 for guiding a drill or other cutting instrument and forming corresponding iliac bores 150, 152 from the iliac crest 32 through the iliac wing 30. The iliac guiding elements 122, 124 are configured preoperatively with patient-specific orientations and locations. The openings 123, 125 of the iliac guiding elements 122, 124 can be tapered and sized to receive a drill bit either directly or indirectly by receiving a sleeve or other drill guide to stabilize and guide a drill. In other embodiments, the openings 123, 125 can be cylindrical to limit space requirements. In some embodiments, a metal sleeve may be press-fitted into a corresponding opening 123, 125 to provide additional rigidity and stability, especially when the universal guide 100, 100′ (or any of the patient-specific alignment guides) is made of polymer or other plastic.
In some embodiments, a drill guide can be used to guide a drill, such as the drill guide 200 shown in FIGS. 4C and 4D. The drill guide 200 can have a space-saving cylindrical shaft 202 with a cylindrical bore 208 and can be configured to be received into a corresponding opening 123, 125 of a corresponding iliac element 122, 124. Each drill guide 200 can be marked with color-coded and/or raised or embossed marking (e.g., X.Xmm) indicating the size of the corresponding guiding element 122, 124 with which it can be used. The marking 210 can be placed on an outer surface of a block element 204 that is connected to the shaft 202. The block element 204 can be used as a handle and can include grooves 206 or other tactile or frictional formations for facilitating secure hand gripping. The block element 204 can be offset relative to the shaft 202 in a direction that avoids interfering with visualization during the surgical procedure.
Similarly, the guiding elements 122, 124 can be identified with color-coding and/or raised markings indicating size. Embossed or raised markings 113 can also be provided on the bridge 104 to indicate caudal and cephalad directions for the placement of the universal guide 100, 100′ (and the other patient-specific alignment guides of the present teachings).
With continued reference to FIGS. 4-5A, 9 and 10, the universal guide 100, 100′ can include one or more elongated arms 132 extending from the bridge 104 toward the sacrum 40 (left and right arms 132 are illustrated). In some embodiments, the arm 104 can extend from the patient-specific portion 102, rather than from the bridge 104. In some embodiments, the arm 132 can be removably coupled to the patient-specific portion 102 or the bridge 104 by a quick-connect/disconnect coupling, such as snap-fit, tongue and groove, taper-to-taper, etc., as shown in an exemplary illustration of FIG. 4A. Each arm 132 can support one (or more) sacral guiding elements 130 having corresponding openings 131. The arm 132 can be curved and oriented such that the sacral guiding element 130 is positioned in a preoperatively determined position and orientation for the specific patient based on the preoperative plan for the patient. The opening 131 of the sacral guiding element 130 can be tapered and sized to receive a drill bit or a sleeve (not shown) for stabilizing and guiding a drill. The sacral guiding element 130 is configured preoperatively with patient-specific orientation and location for guiding a sacral bone screw 65 through a bore 154 drilled from the sacrum 40 into the iliac wing 30 of the patient, as shown in FIGS. 9 and 10. Additionally, the orientations and positions of the iliac guiding elements 122, 124 and sacral guiding elements 130 are configured to avoid interference among the trajectories of the corresponding bone screws and provide anchoring in non-deficient cortical bone. In some embodiments, placement of the bone screws at patient-specific distances from the sciatic notch is preoperatively configured by the arrangement of the iliac and sacral guiding elements 122, 124, 130. Further, in some embodiments, all or some of the iliac and/or sacral guiding elements 122, 124, 130 can be modular or removable and couplable to the corresponding patient-specific portions 102 with taper-to-taper connections, bayonet connections, threadable connections, snap-fit connections or other removable or releasable connections, as illustrated in FIG. 4B. The iliac sacral guiding elements 122, 124, 130 can be color-coded and marked for size with raised or embossed markings, as discussed above.
Each of the patient-specific portions 102 can also include a fixation guiding element 120 with a corresponding opening 121 for guiding a temporary fixation guiding element such as a trocar pin or the pin 140 shown in FIG. 6A for temporarily attaching the universal guide 100, 100′ on the pelvis of the patient. The opening 121 of the fixation guiding element 120 can be smaller in diameter than the openings 123, 125 and 131 of the corresponding iliac and sacral guiding elements 122, 124 and 130 that are used for drilling bores for the bone screws 62 of the iliac and sacral screw assemblies, as shown in FIG. 9. The fixation guiding element 120 is shown as located cephaladly (superiorly) on the patient-specific portion 102 of the universal guide 100 in FIGS. 4 and 5, and caudally (inferiorly) on the patient-specific portion 102 of the universal guide 100′shown in FIG. 5A. In some embodiments, the patient-specific portion 102 of the universal guide 100′ can extend further caudally along the iliac crest 32, and the bridge 104 of the universal guide 100′ can extend from a position cephalad to the fixation guiding element 120, as shown in FIG. 5A. The locations of the temporary fixation pins 140 that are used to support the universal alignment guide 100 on the pelvis are shown at 157 in FIG. 9.
Referring to FIGS. 9-13, after the iliac and sacral bores 150, 152, 154 have been formed using the universal guide 100, 100′, the universal guide 100, 100′ is removed from the pelvis and preoperatively selected and determined portions 37 of the iliac crests 32 can be resected to create a planar recess or seat 38 to accommodate the receivers 64 of the first and second iliac screw assemblies 61, 63 shown in FIGS. 11-13.
Referring to FIGS. 6-8, the iliac guide 100A, sacral guide 100B and unilateral guide 100C are more specialized versions of the universal guide 100, 100′. The iliac guide 100A, as shown in FIG. 6, is similar to the universal guide 100 shown in FIG. 5, but with the sacral guiding elements 130 omitted. It will be appreciated, however, that in other embodiments, the iliac guide 100A can be arranged as the universal guide 100′ shown in FIG. 5A, but with the sacral guiding elements 130 omitted.
The sacral guide 100B, as shown in FIG. 7, is similar to the universal guide 100 shown in FIG. 5, but with the iliac guiding elements 122, 124 omitted. It will be appreciated, however, that in other embodiments, the sacral guide 100B can be arranged as the universal guide 100′ shown in FIG. 5A, but with the iliac guiding elements 122, 124 omitted.
The unilateral guide 100C, as shown in FIG. 8, is similar to the one side (left side is shown) of the universal guide 100′ shown in FIG. 5A, without the bridge 104 and without the sacral guiding element 130. It will be appreciated, however, that in other embodiments, the unilateral guide 100C can be arranged as the universal guide 100 shown in FIG. 5, without the bridge 104 and without the sacral element 130. The unilateral guide 100C, as shown in FIG. 8, is a left side iliac unilateral guide. A right side iliac unilateral guide can be similarly constructed. Additionally, unilateral (left or right side) sacral guides can be constructed by using the arrangement of the sacral guide 100B shown in FIG. 7 without the bridge 104 and without the opposite side patient-specific portion 102.
Although various separate patient-specific unilateral, iliac and sacral can be constructed for a specific patient and surgeon, the patient-specific universal guide 100, 100′ forms a bilateral sacroiliac guide that can be utilized intraoperatively to cover any intraoperative change in plan or intraoperative event for the specific patient. For example, if the surgeon decides to only do a unilateral fixation using sacral and/or iliac bone screws on the left (right) side only, then the corresponding iliac and/or sacral guiding elements of the opposite right (left) side can simply not be used (no drilling on that side). In this respect, removable plugs or covers can be provided in all or some of the guiding elements, such that attention is directed to which guiding elements should be used by positively removing the plugs and exposing the corresponding guiding openings.
Another option is to decouple the bridge 104 and the right (left) side of the universal guide 100, 100′ from the left (right) side and completely remove it. Similarly, the universal guide 100, 100′ can be used for iliac fixation only or for sacral fixation only by not using or by removing those iliac or sacral guiding elements that are not needed. Additionally, the universal guide 100, 100′ can be fully modular, as described above, and constructed as a bilateral sacroiliac guide with a removable bridge 104 and removable iliac and sacral guiding elements 122, 124, 130 and/or arms 132. The modular universal guide 100, 100′ is intraoperatively convertible and reconfigurable at the discretion of the operating surgeon. Accordingly, the same universal patient-specific guide 100, 100′ can be used in several different fixation options of the same patient. As these fixation options are changed or selected intraoperatively, the modular universal guide 100, 100′ provides the surgeon with intraoperative flexibility, reconfigurability and adaptability to an intraoperative change of plan and surgical procedure informed by intraoperative and possibly unanticipated circumstances. Color-coding and raised or embossed markings indicating size, orientation or other relevant information, such as, for example, patient identification, guide or element type and position, can help streamline intraoperative assembling, positioning and use and help avoid errors. At the same time, and regardless of the fixation option selected, the features and advantages of using a patient-specific guide are retained.
The universal guide 100, 100′ (or the iliac guide 100A, or the sacral guide 100B, or the unilateral guide 100C) is removed from the pelvis after the bone bores (150, 152, 154) for the selected fixation procedure have been drilled into the bone. The bone bores (150, 152, 154) are used to guide corresponding bone screw assemblies of a selected fixation system 50 according to the surgical technique associated with the fixation system.
Referring to FIGS. 14-26, patient-specific pedicle alignment guides 300, 300′ 300 illustrated in FIGS. 14 and 300′ illustrated in FIG. 22) are configured to conform and mate in patient-specific manner (as defined above) with corresponding portions of the spinous process 82 and transverse processes 84 of a vertebra 80, as shown in FIG. 14. Three adjacent vertebrae 80A, 80B (superior to 80A), 80C (inferior to 80A) are shown in FIG. 14. The letters A, B, C will be appended to distinguish between the three vertebrae 80 and their corresponding spinous processes 82 (82A, 82B, 82C) and transverse processes 84 (84A, 84B, 84C), as needed.
More specifically, and in reference to FIGS. 14, 19 and 20, the patient-specific pedicle alignment guide 300 is configured to be mounted on vertebra 80A and provide clearance for the spinous process 82B of adjacent and superior vertebra 80B. The patient-specific pedicle alignment guide 300A has a U-shaped guide body 302 formed by first and second elongated members (or legs) 304, 306 defining a U-shaped opening 308 therebetween and joined at a distal portion 310. The distal portion 310 of the guide body 302 has a patient-specific surface 312 designed and shaped from the medical scans of the patient to conform and mate with a corresponding distal surface 86A of the spinous process 82A of vertebra 80A. The upper portion of each of the first and second arms 304, 306 forms a corresponding first and second hook 314, 316 for engaging the corresponding transverse processes 84A of the vertebra 80A. The first hook 314 has a patient-specific undersurface 318 and the second hook 316 has a patient-specific undersurface 320, each of the undersurfaces 318, 320 configured to conform and mate with a corresponding transverse process 84A (right and left) of the vertebra 80A. Each hook 314, 316 is attached to a corresponding block or extension 322, 324 with corresponding guiding drill bores 326, 328 for drilling holes and guiding pedicle screws along patient-specific orientations, as discussed below. Metallic drill guides can be inserted in the drill bores 326, 328 to facilitate drilling for the insertion of pedicle screws. The drill bores 326, 3278 can be tapered to guide drilling and inserting the pedicle along patient-specific orientation or pedicle trajectories determined during the preoperative plan, as discussed below.
With continued reference to FIG. 14, the patient-specific pedicle alignment guide 300 is configured to avoid interference with the upper and lower vertebral levels, i.e. vertebrae 80B and 80C, during and after placement and minimize contact with associated soft tissue. More specifically, the first and second legs 304 and 306 and the opening 308 are patient-specific and designed from the medical scans of the specific patient to accommodate and centrally receive the spinous process 82B of the upper vertebra 80B. Additionally, a clearance or gap is provided between the guide body 302 and the spinous process 82A away from the contact region between 312 and 86A, because the guide body 302 is configured to be angled away and above the spinous process 82A, as seen for example in FIG. 17.
Referring to FIGS. 15 and 16, the pedicle screw trajectories are patient-specific and vertebra-specific and can be determined preoperatively using the medical scans of the patient. FIG. 15 illustrates a selected pedicle trajectory PT for a pedicle screw on a transverse view of a CT image the vertebra 80A. FIG. 16 illustrates the selected trajectory PS on a sagittal view of a CT image the vertebra 80A (same reference numbers are used for the vertebra and its image). More specifically, the width of the pedicles 83 can be determined from the transverse image of FIG. 15 and define the trajectory PT on the transverse plane such that it bisects the pedicle 83. Referring to FIG. 16, the center C of the pedicle 83 can be defined as the intersection of the transverse, sagittal and coronal planes bisecting the pedicle 83. The pedicle trajectory PS in the sagittal plane can be determined either by optimizing the trajectory to maximize the length of the corresponding pedicle screw in the vertebral body 81 or by positioning the screw 330 parallel to the superior endplate of the vertebral body (shown in FIG. 25) to provide maximum pull-out strength. Additionally, the diameter of the pedicle screw 330 (shown in FIGS. 17 and 18) can be determined as substantially the largest diameter that will not perforate the corresponding medial and lateral pedicle walls. The pedicle screw entry points can then be determined for the defined screw trajectory and used to position and configure the drill bores 326, 328 on the patient-specific pedicle alignment guide 300, such that holes for pedicle screws drilled through the guiding drill holes are centered along the corresponding pedicle 83 and have a maximum or large length through their vertebral body 81 for positioning the corresponding pedicle screws 330, as illustrated in FIGS. 17 and 18.
Referring to FIGS. 21-26, another embodiment of the patient-specific pedicle alignment guide 300′ is illustrated. The embodiment 300 is similar to the embodiment 300, but includes as an additional element an arcuate bridge 350. Elements that are common between the embodiments 300, 300′ are referenced with the same numerals and their description is not repeated.
As can be seen from FIGS. 21-26, the arcuate bridge 350 forms a three-dimensionally curved connector between the first and second legs 304, 306 of the patient-specific pedicle alignment guide 300′. The arcuate bridge 350 adds rigidity and helps stabilize the patient-specific pedicle alignment guide 300A in the medial-lateral direction. In some embodiments, the arcuate bridge 350 can be monolithically manufactured or fixedly attached to the first and second legs 304, 306. In other embodiments, the arcuate bridge 350 can be removably attached by a snap-on or other quick-connect connection, such as dovetail, tongue and groove, etc.
The arcuate bridge 350 is configured to have a three-dimensionally curved surface to maintain clearance between the upper and lower vertebrae 80A, 80C such that no bone removal, modification or displacement is required to position the patient-specific pedicle alignment guide 300′ on the patient. The arcuate bridge 350 can include a centrally positioned pressure pad 352 configured to provide a curved surface for applying force and pressure via one or more fingers of the surgeon. The force and pressure can be transmitted perpendicularly to the left and right transverse processes 84A to push the patient-specific pedicle alignment guide 300′ against the bone to secure the guide. The pressure pad 352 can be oval with a concave surface or generally shaped for thumb and/or fingertip contact. The patient-specific pedicle alignment guide 300′ can be configured to include more extensive contact area with the transverse processes 84A and the spinous process 82A in comparison to the patient-specific pedicle alignment guide 300. The increased contact areas provided by extending the hooks 314′, 316′ to contact and mate with increased surfaces of the transverse processes 84A provide additional physical constraints to prevent sliding motion in the medial-lateral direction (right-left) direction. Similarly, increasing the contact area with the spinous process 82A helps prevent distal dislocation of the patient-specific pedicle alignment guide 300′.
Summarizing, the patient-specific pedicle alignment guides 300, 300′ are configured for a specific vertebra 80A of the spine column of a specific patient as well as for the adjacent upper and lower vertebrae 80B, 80C. Accordingly, the patient-specific pedicle alignment guides 300, 300′ are not only customized and are different from patient to patient, but even for the same patient, their size and shape can vary with the location and type of vertebra (i.e., lumbar, dorsal, cerebral and location within each area).
Example embodiments are provided so that this disclosure is thorough, and fully conveys the scope to those who are skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure.
It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Accordingly, individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

## Claims

1. An orthopedic device comprising:
a patient-specific alignment guide configured for a first vertebra of a spinal column of a specific patient, the alignment guide including a U-shaped guide body having first and second legs joined at a distal portion, the distal portion having a patient-specific surface preoperatively configured to mate with a corresponding surface of a spinous process of the first vertebra, the first and second legs having corresponding first and second hooks configured to mate with corresponding portions of first and second transverse processes of the first vertebra,
wherein the first and second legs define an opening configured to provide clearance for a spinous process of a second vertebra that is adjacent and superior to the first vertebra, the opening being on an opposite side of the distal portion as the patient-specific surface preoperatively configured to mate with the corresponding surface of the spinous process of the first vertebra; and
a bridge separate from the distal portion, wherein the bridge traverses the opening and connects the first and second legs at a location spaced from the distal portion.

2. The orthopedic device of claim 1, further comprising first and second patient-specific drilling bores passing through corresponding extensions of the first and second hooks and having patient-specific orientations configured to be centered along corresponding right and left pedicles of the first vertebra and through a vertebral body of the first vertebra.

3. The orthopedic device of claim 1, wherein the bridge is curved and is configured to provide clearance for underlying bone and soft tissue structures.

4. The orthopedic device of claim 1, wherein the bridge includes a pressure pad configured to apply pressure and transmit forces through the first and second hooks to the corresponding first and second transverse processes.

5. The orthopedic device of claim 4, wherein the pressure pad has an oval shape.

6. The orthopedic device of claim 4, wherein the pressure pad has a concave surface configured for fingertip contact.

7. An orthopedic device comprising:
a patient-specific alignment guide configured for a first vertebra of a spinal column of a specific patient, the alignment guide including a U-shaped guide body having first and second legs joined at a distal portion, the distal portion having a patient-specific surface preoperatively configured to mate with a corresponding surface of a spinous process of the first vertebra, the first and second legs having corresponding first and second hooks configured to mate with corresponding portions of first and second transverse processes of the first vertebra,
wherein the first and second legs define an opening configured to provide clearance for a spinous process of a second vertebra that is adjacent and superior to the first vertebra, the opening being on an opposite to-side of the distal portion as the patient-specific surface preoperatively configured to mate with the corresponding surface of the spinous process of the first vertebra; and
an arcuate bridge separate from the distal portion, wherein the bridge traverses the opening and connects the first and second legs at a location proximal to the distal portion.

8. The orthopedic device of claim 7, wherein the arcuate bridge is curved and is configured to provide clearance for underlying bone and soft tissue structures.

9. The orthopedic device of claim 8, wherein the arcuate bridge includes a pressure pad configured to apply pressure and transmit forces through the first and second hooks to the corresponding first and second transverse processes.

10. The orthopedic device of claim 9, wherein the pressure pad has an oval shape.

11. The orthopedic device of claim 9, wherein the pressure pad has a concave surface configured for fingertip contact.

12. The orthopedic device of claim 7, further comprising first and second patient-specific drilling bores passing through corresponding extensions of the first and second hooks and having patient-specific orientations configured to be centered along corresponding right and left pedicles of the first vertebra and through a vertebral body of the first vertebra.

13. An orthopedic device comprising:
a first patient-specific element having a first patient-specific surface preoperatively configured to mate and conform to a first transverse process of first vertebra of a specific patient based on medical scans of the patient at a proximal end of the first patient-specific element,
a second patient-specific element having a second patient-specific surface preoperatively configured to mate and conform to a second transverse process of the first vertebra of the specific patient based on medical scans of the patient at a proximal end of the second patient specific element;
a third patient-specific element positioned between and coupling the first and second patient-specific elements at distal ends of the first and second patient-specific elements, and having a third patient-specific surface preoperatively configured to mate with a corresponding surface of a spinous process of the first vertebra; and
an arcuate bridge coupling the first and second patient-specific portions, wherein the arcuate bridge is spaced from the third patient-specific element between the proximal and distal ends of the first and second patient-specific elements, the arcuate bridge configured to provide clearance for a second vertebra between the first and second transverse processes,
wherein the third patient-specific element has a proximal surface proximate the first and second patient-specific elements and a distal surface distal to the first and second patient-specific elements, the distal surface defining the third patient-specific surface.

14. The orthopedic device of claim 13, further comprising first and second patient-specific drilling bores passing through the corresponding first and second patient-specific elements and having patient specific-orientations for guiding fixation elements into the corresponding first and second transverse processes.

15. The orthopedic device of claim 13, wherein the arcuate bridge includes a pressure pad configured to apply pressure and transmit forces through the first and second patient-specific elements.

16. The orthopedic device of claim 13, wherein the first and second patient-specific elements collectively define an opening configured to provide clearance for a spinous process of the second vertebra that is adjacent and superior to the first vertebra, the opening being on an opposite side of the third patient-specific element as the third patient-specific surface.