Spine. THOR Anterior Lumbar Plate Operative Technique

Transcription

1 Spine THOR Anterior Lumbar Plate Operative Technique

2 Table of Contents THOR Anterior Lumbar Plate Surgical Technique Introduction 3 Implants 4 Instruments 5-6 Procedure 7-12 Removal of Implants 13 Indications and Contraindications

3 Introduction The THOR Plating System has been designed to be a more versatile and user friendly anterior lumbar fusion plate. The THOR plate combines the strength of fixed angle screws with the versatility of variable angle screw trajectory and the bone to plate interface afforded by lag fixation. It is designed with the ability to mechanically apply compression to the graft if desired. The application of THOR is simplified by an All-in-One-Guide which is designed to facilitate safe drilling and screw placement without repeated instrument exchange from the wound. The locking device is designed to be more easily engaged after all screws are placed and the surgeon is pleased with screw length and position. The plate is provided in four configurations; a one and two level Sacral plate with compression (THOR Sacral), a single level L1 - L5 plate with compression (THOR Lumbar), and a single level L1 - S1 plate without compression (THOR Universal). These configurations are provided in various sizes in 3mm increments, along with 6.0 and 6.5mm diameter screws. Acknowledgements Stryker Spine would like to thank the following surgeons for their dedication and contributions: Michael Dube, MD Frederick Marciano, MD, PhD Randall Porter, MD Nicholas Theodore, MD Eeric Truumees, MD 3

4 Implants One Level Sacral Compression Plate (25-37mm) This plate is used for L5 - S1 with the option for compression. It has a small ridge that assists with placement onto the sacrum. The sizes range from 25-37mm in 3mm increments XX (25-37) Two Level Sacral Compression Plate (65-89mm) This plate is used for L4 - S1 with the option for compression. It has a small ridge that assists with placement onto the sacrum. The sizes range from 65-89mm in 6mm increments XX (65-89) One Level Compression Plate (25-37mm) This plate is used for L1 - L5 with the option for compression. The sizes range from 25-37mm in 3mm increments XX (25-37) One Level Non Compression Plate (22-40mm) This plate is used for L1 - S1 without the option for compression. The sizes range from 22-40mm in 3mm increments XX (22-40) Standard Screw Standard Bone Screw. The screws come in two diameters, 6.0 and 6.5mm, and lengths ranging from 22-37mm in 3mm increments xx (22-37) and xx (22-37) Compression Screw Standard Bone Screw inserted through the compression hole on the plate into the spine. These screws come in two diameters, 6.0 and 6.5mm, and two lengths 22 and 35mm , , ,

5 Instruments Fixation Pin Inserter Used to insert the Fixation Pin into the spine Short Fixation Pin (21mm length, 3mm diameter) Used to hold the plate in place on the spine while the initial screw is inserted. This is removed and replaced with a screw once the plate is secure to the spine Medium Fixation Pin (28mm length, 3mm diameter) Used to hold the plate in place on the spine while the initial screw is inserted. This is removed and replaced with a screw once the plate is secure to the spine Long Fixation Pin (34mm length, 3mm diameter) Used to hold the plate in place on the spine while the initial screw is inserted. This is removed and replaced with a screw once the plate is secure to the spine All-in-One-Guide (AIOG) The AIOG rigidly holds the plate, allowing controlled insertion into the surgical field. Once positioned against the spine, all of the instruments needed to fix the plates are passed through its hollow shaft, thereby decreasing instrument exchanges and the risk of soft tissue injury Locking Guide Expander - The Locking Guide Expander is designed to be inserted into the AIOG and partially tightened, before inserting the Alignment Rod. Once the completely assembled AIOG is inserted into a ring, the knurled portion of the Locking Guide Expander may be final tightened for a more rigid connection to the ring AIOG Alignment Rod Used to align the AIOG within the locking rings of the plate. Once the AIOG is attached to the plate, the Alignment Rod is removed. It is only used for aligning the AIOG within the rings Awl (17mm length, 4mm diameter) Used to create an entry point into the cortical envelope of the vertebral body Awl Guide Used to guide the Awl into the compression hole on the compression plates Depth Gauge Probe Used to measure the depth of the hole prior to screw selection

6 Instruments Gauge Disk Used to show the length on the Depth Gauge, Tap, or Drill Feeler Probe Used to check the integrity of the hole prior to screw insertion Drill Used to prepare a screw tract in the vertebral body Tap Used to tap the hole in the spine prior to screw insertion Screwdriver Shaft Holds the Standard and Compression Screws and is used for screw insertion Universal Screwdriver Shaft Additional screwdriver option, can also be used for revisions Torque Wrench Used to apply the final tightening torque to the locking rings of the plate Torque Wrench Socket - Adheres to the end of the Torque Wrench and aligns with locking ring during final tightening Anti Torque Key Used to immobilize the plate when the final tightening torque is applied

7 Procedure Please review the surgical technique in its entirety. Use of the All-in-One-Guide (AIOG) is MANDATORY to insert the Standard Bone Screws. This will help prevent screw overangulation. 1) An anterior transabdominal or retroperitoneal approach can be utilized to expose the L5-S1 or L4-L5 disc space. Once identified as the correct surgical level, the disc space can be prepared for placement of the interbody fusion device. 2) Once the interbody fusion device is placed, a caliper or similar device is used to measure the distance between the chosen location for screws. The plate measurements will correspond to the distance between screw holes and will be available in increments of 3mm. 3) Once the proper plate size is chosen, the All-in-One-Guide (AIOG) ( ) is attached to the plate in one of the locking ring locations. (Please ensure that the Locking Guide Expander ( ) is fully seated). Figure 1 Lever Arm AIOG Use of the AIOG helps to: 1. Ensure less sharp instruments in and out of the wound 2. Prevent soft tissue creep Use of the Alignment Rod helps to: 1. Engage the AIOG onto the plate 2. Prevent overangulation of the AIOG Alignment Rod Locking Guide Expander To assemble the AIOG, first place the Locking Guide Expander through the hollow cannula. Finger tighten using the knurled grip. To finish, place the Alignment Rod ( ) through the assembly. Figure 2 The Alignment Rod is used to align the AIOG to the plate. Placing the Alignment Rod down the hollow cannula will ease engagement of the AIOG to the locking ring. Note: The AIOG should not be attached to the plate without the Alignment Rod. Use of the AIOG and Alignment Rod is MANDATORY. Once the AIOG has been placed in a locking ring, the Locking Guide Expander may be final tightened to help create a more rigid connection to the ring. 4) Closing the lever arm of the AIOG will provide a more rigid attachment to the plate. Using AIOG as a plate holder the plate can then be held in position to verify proper length. The angle of the screws is not locked until the lever arm is engaged. This allows the surgeon to place the plate, and then adjust the screw angles. Figure 3a Note: Be careful to not apply clockwise rotational force to the AIOG. Clockwise rotational force could cause the ring to rotate into a provisionally locked position. If this happens intra-operatively, rotate the AIOG counterclockwise to the unlocked position (see Figure 3a), with the lever arm fixed. Figure 3b Note: Do not overangulate the AIOG. Overangulation of the AIOG could result in screw overangulation, and eventually difficulty making the screw sit flush within the ring. If this happens, remove the screw using the Universal Screwdriver Shaft ( ). Disengage the lever arm, and reengage the AIOG to its appropriate position using the Alignment Rod. 7

8 5) There is a transverse ridge on the posterior surface of the plate which should be placed on the superior end plate of S1 (Figure 4). Using the AIOG as a holder, place the plate against the spine for fixation. Remove Alignment Rod from AIOG. Figure 4 Fixation Pin Inserter 6) A temporary Fixation Pin (short , medium , long ) may now be placed through the AIOG (Figure 5). Attach the Fixation Pin to the Fixation Pin Inserter ( ) by pulling up on the quick release. Once the pin is held secure by the Fixation Pin Inserter, it can be placed through the AIOG into the spine. To release the pin, pull up again on the quick release. Note: Make sure that the pin length selected is appropriate for specific patient anatomy. Figure 5 Note: As an alternate method, you can attach two AIOGs at step 5. This will preclude using the holding pin and allow the screws to be directly placed after preparing the screw pathway. Alignment Rod 7) Remove the AIOG, reinsert the Alignment Rod, and then re-attach the AIOG to the ring at caudal location (Figure 6). Figure 6 8

9 Use of the All-in-One-Guide (AIOG) is MANDATORY. 8) A pilot hole may now be made with the Awl ( ) or Drill ( ). See Figure 7. The depth of the Drill can be preset using the Gauge Disk ( ). See Figure 8a. Attach the Gauge Disk to the Drill by depressing the button on the side of the Gauge Disk and sliding it over the proximal end of the Drill shaft. The setting is determined by what number appears in the Gauge Disk window. When the Gauge Disk bottoms out against the AIOG, the hole will be drilled to the selected depth (Figure 8b). 9) The depth of the pilot hole may be measured using the Depth Gauge Probe ( ). Insert the Depth Gauge Probe into the AIOG. When the Gauge Disk bottoms out, read the corresponding numbers at the top of the AIOG. The integrity of the hole can be checked with the Feeler Probe ( ). Figure 8a Figure 7 10) The hole is then tapped using the 6.0mm Tap ( ). The depth of the Tap can be pre-set in the same manner as the Drill using the Gauge Disk. Note: The 6.0mm Tap is undersized by 0.5mm (True Diameter = 5.5mm) to prepare the pathway for a 6.0mm screw. 11) The proper length 6.0mm screw is attached to the self-holding Screwdriver Shaft ( ) and then inserted (Figure 9). When finished, ensure that the black line on the Screwdriver Shaft is flush with the AIOG (Figure 10). Remove the Screwdriver Shaft. If desired, a 6.5mm rescue screw is available. Black Line Figure 8b Black Line Flush with AIOG Note: Once screw is inserted, the Universal Screwdriver Shaft is recommended to further advance the screw into the vertebral body. Figure 9 Figure 10 9

10 Removal of Fixation Pin Figure 11 12) With the Standard Screw fully inserted, the temporary Fixation Pin can now be removed using the Fixation Pin Inserter (Figure 11). 13) Repeat steps 8-11 for the adjacent caudal location. If desired, the Standard Screws can be advanced using the Universal Screwdriver Shaft to lag the plate to the bone. If compression is not desired, repeat steps 8-11 for all remaining holes and skip to step 18 on Page 12. Awl Awl Guide Note: Please ensure that the Standard Screws are fully seated into the locking rings of the plate. If not fully seated, the Torque Wrench ( ) will not be able to engage the locking rings around the screw heads. 14) The Compression Screw ( , , , ) is now placed. Insert the Awl Guide ( ) into the compression hole (or oval). Insert Awl to make pilot hole into the vertebral body (Figure 12). Figure 12 Note: The Awl Guide should be used to ensure the proper starting point for the compression hole. 15) Insert the Drill and/or the Tap through the Awl Guide to prepare the screw pathway in the vertebral body (Figure 13). Measure the depth of the pathway and remove the Awl Guide. Choose either the 6.0/6.5mm x 22/35mm Compression Screw. Figure 13b Figure 13a 10

11 16) Remove the Awl Guide and insert the Compression Screw into the vertebral body using the self-holding Screwdriver Shaft. Tighten the Compression Screw until it is below the locking ridge of the compression hole (portion of black ring will be obscured by the compression ridge). Compression will take place as the screw slides down the compression hole ramp (Figure 14a). Black Ring Compression Ridge Note: The screw must be under the compression ridge to prevent backout postoperatively (Figure 14b). Note: To achieve compression, the caudal Standard Bone Screws must be inserted first, followed by the Compression Screw, and then the cephalad Standard Bone Screws. Figure 14b Figure 14a 17) Once the Compression Screw is in place, repeat steps 8-11 for the remaining cephalad screw hole locations (Figure 15). If desired, the Standard Screws can be advanced using the Universal Screwdriver Shaft to lag the plate to the bone. Cephalad Standard Screws Note: Please ensure that the Standard Screws are fully seated into the locking rings of the plate. If not fully seated, the Torque Wrench will not be able to engage the locking rings around the screw heads. Figure 15 11

12 Place the Torque Wrench Socket ( ) onto the end of the Torque Wrench. See Figure 16b. Figure 16a Anti-Torque Key Anti-Torque Key Slot 18) To lock the Standard Screws, insert the Anti-Torque Key ( ) into the Anti-Torque Key slot on the plate. Insert the Torque Wrench with socket into the locking ring and turn clockwise until the arrows on the proximal end of the Torque Wrench line up (12Nm). This will lock the screw to the plate and fix the angle. Repeat for all of the Standard Screws. Torque Wrench Socket The Anti-Torque Key must be used to prevent rotational forces from being applied to the spine when locking the system. Torque Wrench Perform a visual check to ensure locking ring is in the locked position. Figure 16b The ring is in the locked position when the locking ring slot is aligned with the black laser etching on the plate (Figure 17a). Locked Locking Ring Slot Black Laser Etching Unlocked If at any time after the screws are locked into position, it is deemed necessary to remove one or all of the screws, they may be removed by turning the locking ring counterclockwise with the Torque Wrench to unlock the ring. The Standard Screw can now be removed with the Universal Screwdriver Shaft. Figure 17a Figure 17b Note: If the Torque Wrench is not able to engage in the ring, this is an indication that the screw is not flush within the ring. If this happens, remove the screw and turn the ring counterclockwise with the Torque Wrench. Once the ring is in the unlocked position, reinsert the screw, being sure to secure proper angulation by using the fully assembled AIOG. Surgical Technique One Level Lumbar Compression Plate (L1-L5): Note: These plates are placed in the same manner as One Level Sacral Compression Plates. Repeat steps 1 16 above. There will not be a sacral ridge for placing the plate. Surgical Technique Universal One Level Lumbar Non-Compression Plate (L1-S1): Note: When the Universal non-compression plate is chosen, the technique can be altered by allowing placement of screws in any order. This plate does not have a compression hole. The remainder of the technique is identical. Repeat steps 1 12, and 18 above. There will not be a sacral ridge for placing the plate. 12

13 Removal of Implants These implants are temporary internal fixation devices designed to stabilize the operative site during the normal healing process. After healing occurs, these devices serve no functional purpose and can be removed. Removal may also be recommended in other cases, such as: 1) Corrosion with a painful reaction 2) Migration of the implant, with subsequent pain and/or neurological, articular or soft tissue lesions 3) Pain or abnormal sensations due to the presence of the implants 4) Infection or inflammatory reactions 5) Reduction in bone density due to the different distribution of mechanical and physiological stresses and strains 6) Failure or mobilization of the implant Standard ancillaries provided by STRYKER Spine can be used to remove the implants. Any decision by a physician to remove the internal fixation device must take into consideration such factors as the risk to the patient of the additional surgical procedure as well as the difficulty of removal. Removal of an unloosened spinal screw may require the use of special instruments to disrupt the interface at the implant surface. This technique may require practice in the laboratory before being attempted clinically. Implant removal should be followed by adequate postoperative management to avoid fracture or re-fracture. Removal of the implant after fracture healing is recommended. Metallic implants can loosen, bend, fracture, corrode, migrate, cause pain or stress shield bone. If removal is desired, insert the Anti-Torque Key into the Anti-Torque Key slot on the plate. While holding the Anti-Torque Key, use the Torque Wrench with Torque Wrench Socket attached and apply a counterclockwise turn to loosen the locking rings. Perform this for each locking ring. Once all of the rings are loosened, remove the bone screws using the Universal Screwdriver Shaft. The same instrument is used to remove the compression screw if applicable. Once all of the screws have been removed, the plate can be removed from the spine. 13

14 Indications The STRYKER Spine THOR Anterior Plating System is indicated for use via a lateral or anterolateral surgical approach above the bifurcation of the great vessels or anterior surgical approach below the bifurcation. The STRYKER Spine THOR Anterior Plating System is intended for use in the lumbar and lumbosacral spine (L1 S1). THOR Anterior Plating System is intended to provide additional support during fusion in skeletally mature patients in the treatment of the following acute and chronic instabilities or deformities: Specific indications in the treatment of lumbar and lumbosacral (L1-S1) spine instability as a result of: 1) Degenerative disc disease (defined as back pain of discogenic origin with degenerative disc confirmed by history and radiographic studies) 2) Pseudoarthrosis 3) Spondylolysis 4) Spondylolisthesis 5) Trauma (i.e. Fracture or dislocation) 6) Deformities (i.e., scoliosis or lordosis) 7) Spinal stenosis 8) Failed previous fusion Contraindications Contraindications may be relative or absolute. The choice of a particular device must be carefully weighed against the patient s overall evaluation. Circumstances listed below may reduce the chances of a successful outcome: Any abnormality present which affects the normal process of bone remodeling including, but not limited to, severe osteoporosis involving the spine, bone absorption, osteopenia, primary or metastatic tumors involving the spine, active infection at the site or certain metabolic disorders affecting osteogenesis. Insufficient quality or quantity of bone which would inhibit rigid device fixation. 1) Previous history of infection 2) Excessive local inflammation 3) Open wounds 4) Any neuromuscular deficit which places an unusually heavy load on the device during the healing period. 5) Obesity. An overweight or obese patient can produce loads on the spinal system which can lead to failure of the fixation of the device or to failure of the device itself. 6) Patients having inadequate tissue coverage of the operative site. 7) Pregnancy. 8) A condition of senility, mental illness, or substance abuse. These conditions, among others, may cause the patient to ignore certain necessary limitations and precautions in the use of the implant, leading to failure or other complications. 9) Foreign body sensitivity. Where material sensitivity is suspected, appropriate tests must be made prior to material selection or implantation. 10) Other medical or surgical condition which would preclude the potential benefit of spinal implant surgery, such as the presence of tumors, congenital abnormalities, elevation of sedimentation rate unexplained by other diseases, elevation of white blood cell count (WBC), or marked left shift in the WBC differential count. These contraindications can be relative or absolute and must be taken into account by the physician when making his decision. The above list is not exhaustive. Pre-operative Precautions Anyone using STRYKER Spine products can obtain a Surgical Technique brochure by requesting one from a distributor or from STRYKER Spine directly. Those using brochures published more than two years before the surgical intervention are advised to get an updated version. STRYKER Spine devices must only be used by doctors who are fully familiar with the surgical technique required and who have been trained to this end. The doctor operating must take care not to use the instruments to exert inappropriate stress on the spine or the implants and must scrupulously comply with any operating procedure described in the surgical 14

15 technique provided by STRYKER Spine. For example, the forces exerted when repositioning an instrument in-situ must not be excessive as this is likely to cause injury to the patient. To reduce the risks of breakage, care must be taken not to distort the implants or nick, hit or score them with the instruments unless otherwise specified by the applicable STRYKER Spine Surgical Technique. Extreme care must be taken when the instruments are used near vital organs, nerves or vessels. Unless otherwise specified on the label, the instruments can be reused after decontamination, cleaning and sterilization. Information for Patients The surgeon must discuss all physical and psychological limitations inherent to the use of the device with the patient. This includes the rehabilitation regimen, physical therapy, and wearing an appropriate orthosis as prescribed by the physician. Particular discussion should be directed to the issues of premature weightbearing, activity levels, and the necessity for periodic medical follow-up. The surgeon must warn patients of the surgical risks and made aware of possible adverse effects. The patient must be warned that the device cannot and does not replicate the flexibility, strength, reliability or durability of normal healthy bone, that the implant can break or become damaged as a result of strenuous activity or trauma, and that the device may need to be replaced in the future. If the patient is involved in an occupation or activity which applies inordinate stress upon the implant (e.g., substantial walking, running, lifting, or muscle strain)the surgeon must warn the patient that resultant forces can cause failure of the device. Patients who smoke have been shown to have an increased incidence of non-unions. Such patients must be advised of this fact and warned of the potential consequences. For diseased patients with degenerative disease, the progression of degenerative disease may be so advanced at the time of implantation that it may substantially decrease the expected useful life of the appliance. In such cases, orthopaedic devices may be considered only as a delaying technique or to provide temporary relief. Caution Federal law (U.S.A) restricts this device to sale by or on the order of a licensed physician Warning (U.S.A.) The safety and effectiveness of anterior plating spinal systems have been established only for spinal conditions with significant mechanical instability or deformity requiring fusion with instrumentation. These conditions are significant mechanical instability or deformity of the thoracic, lumbar, and sacral spine secondary to spondylolisthesis, fracture, dislocation, scoliosis, kyphosis, spinal tumor, and failed previous fusion (pseudoarthrosis). The safety and effectiveness of these devices for any other conditions are unknown. 15

16 Joint Replacements Trauma Spine Micro Implants Orthobiologics Instruments Interventional Pain Navigation Endoscopy Communications Patient Handling Equipment EMS Equipment EU Operations Z.I. Marticot Cestas - FRANCE Phone: +33 (0) Fax: +33 (0) Web: US Operations 2 Pearl Court, Allendale, New Jersey USA Phone: Fax: Web: THOR is a registered trademark of Stryker Spine. A surgeon must always rely on his or her own professional clinical judgment when deciding whether to use a particular product when treating a particular patient. Stryker does not dispense medical advice and recommends that surgeons be trained in the use of any particular product before using it in surgery. The information presented is intended to demonstrate the breadth of Stryker product offerings. A surgeon must always refer to the package insert, product label and/or instructions for use before using any Stryker product. Products may not be available in all markets because product availability is subject to the regulatory and/or medical practices in individual markets. Please contact your Stryker representative if you have questions about the availability of Stryker products in your area. Products referenced with designation are trademarks of Stryker. Products referenced with designation are registered trademarks of Stryker. Literature Number: TLTHOST09073 SC/GS Copyright 2009 Stryker Printed in USA