O.I.C. Cage UniLIF Surgical Technique

Transcription

1 Spine O.I.C. Cage UniLIF Surgical Technique O.I.C. PEEK O.I.C. Titanium DRAFT

2 Unilateral Lumbar Interbody Fusion Technique Acknowledgements Stryker Spine wishes to thank the following physicians for authoring this surgical technique: Daryll C. Dykes, MD, PhD Twin Cities Spine Center Minneapolis, Minnesota Richard G. Fessler, MD, PhD Northwestern University Chicago, Illinois Jeffrey S. Fischgrund, MD William Beaumont Hospital Royal Oak, Michigan Scott H. Kitchell, MD Orthopedic Spine Associates Eugene, Oregon Amir A. Mehbod, MD Twin Cities Spine Center Minneapolis, Minnesota Eeric Truumees, MD William Beaumont Hospital Detroit, MI Additionally, Stryker Spine wishes to thank the global O.I.C Cage System surgeon panel for their dedication to the development of the O.I.C Cage System.

3 Table of Contents UniLIF Surgical Technique Introduction 04 Posterior Interbody Fusion with the Stryker O.I.C. Cage 05 Step 1 - Exposure 08 Step 2 - Preparation of Facet Joints 08 Step 3 - UniLIF Site Preparation 09 Step 4 - Distraction 09 Step 5 - Discectomy and Endplate Preparation 11 Step 6 - Sizing the Disc Space 12 Step 7 - O.I.C. Cage Preparation 12 Step 8 - O.I.C. Cage Insertion 13 Step 9 - Placement of Bone Grafting Material 14 Step 10 - Implant Options 15 Step 11 - Closure 16 PEEK Cage Reference Numbers 17 Titanium Cage Reference Numbers 18 Instrument Reference Numbers 19

4 Introduction Procedure Stryker Spine enters a new procedural realm called UniLIf (Unilateral Lumbar Interbody Fusion). This procedure calls for the unilateral insertion of a single implant into the disc space through a PLIF approach, TLIF approach, or anywhere in between, designed for both open or less invasive procedures. Description The O.I.C. Cage System offers three implants for the UniLIF procedure: the O.I.C. PEEK cage, the O.I.C PEEK-UniLIF cage, O.I.C. II, and the O.I.C. Titanium cage. These cages are intended for use as an aid in spinal fixation. These hollow, rectangular implants are offered in a variety of widths, lengths, heights and lordotic angles designed to adapt to a variety of patient anatomies. They have serrations on the superior and inferior surfaces designed for fixation, ergonomically shaped anterior edges, and flat posterior edges. Radiopaque markers have been embedded within the PEEK implants, which are designed to allow for visualization in radiographic images.

5 Posterior Interbody Fusion with the Stryker O.I.C Cage Eeric Truumees, MD Posterior interbody fusion techniques are increasingly recommended by spine surgeons. Improved surgical techniques and improved interbody implants are among the reasons interest in these techniques is increasing. Posterior interbody procedures provide both posterior and anterior stabilization through a single incision. Posterior interbody fusion represents a spectrum of techniques. These procedures can be performed as a PLIF, or Posterior Lumbar Interbody Fusion, through a paramedian annulotomy. Alternatively, TLIF, or Transforaminal Lumbar Interbody Fusion, utilizes a farther lateral annulotomy, colinear with the pedicle. In reality, any point between the paramedian and far lateral approach can be selected. What one surgeon may call a TLIF might be termed a PLIF by another. These procedures can be done through traditional open approaches, or they can be performed through tubular retractors in a nearly percutaneous manner, or virtually every point in between. The posterior interbody fusion surgeon has a number of other choices as well. A variety of cage materials and geometries are available for single or paired implantation. Typically, adjunctive stabilization is sought with transpedicular instrumentation. The graft material employed will also vary from iliac crest autograft to local bone. Rationale of Posterior Interbody Surgery Appropriate cage selection requires an understanding of the rationale and biomechanics of interbody procedures. Interbody techniques place the fusion mass under compression and this region has better vascularity than does the posterolateral, inter-transverse space. These techniques afford the surgeon 360 access to the motion segment without a separate, anterior approach. The disadvantages of these procedures need to be considered as well. For PLIF procedures, the surgeon must be careful to avoid excessive nerve root retraction in order to avoid postoperative epidural fibrosis. In TLIF procedures, the sensitive dorsal root ganglion must be protected. Both procedures require segmental destabilization from facet removal. Goals, Indications & Contraindications Regardless of the exact method selected, the goals of posterior interbody surgeries are to achieve a solid, stable arthrodesis of the spinal segment while maintaining proper disc height and restoring sagittal plane alignment. Interbody fusions are also added to longer posterolateral fusions when

6 additional, anterior Indications include: 1. Degenerative Disc Disease 2. Grade 1 Spondylolisthesis Interbody fusions are also added to longer posterolateral fusions when additional anterior column stability is required. For example, in patients with marginal sagittal balance a TLIF/PLIF may prevent post-operative flat-back. Posterior interbody procedures are not appropriate in every clinical situation, however. A number of relative contraindications must be considered when recommending a specific surgical strategy. Similarly, while osteoporotic patients are often more fragile overall, if interbody implants are required, the larger footprint of an ALIF spacer is less likely to subside than a posterior spacer. Alternatively, a bilateral approach may be considered in patients with borderline bone quality. Finally, both PLIF and TLIF procedures must be undertaken with great care in patients with extensive epidural scarring. In those cases, safe dural retraction required for PLIF may be difficult. In TLIF cases, extensive epidural scarring limits the extent to which safe interbody distraction can be achieved. Decision Making Surgeons planning posterior interbody fusions have a number of options in their approach to fit the pathology to be addressed. For example, the relative location of the dorsal root ganglion at the operative level may affect the mediallateral approach angle to the disc space. Similarly, the width of the lateral pars and the pelvis may render PLIF or TLIF more appropriate in a given patient. In males with a narrow pelvis, the L5-S1 disc space may be more easily accessed through a paramedian (PLIF) approach. In the upper lumbar spine (L3-4 and above), the narrow pars and smaller canal to dural diameter ratio makes TLIF the preferred approach in most cases. Important decisions include spacer selection. The Posterior interbody spacers are designed to provide solid structural support until the fusion mass solidifies. The spacer geometry should be optimized for adequate endplate coverage. Overly large spacers are difficult to insert and risk traction injuries to the nerves. Modern spacer designs are often tapered to ease insertion. Interbody fusion spacers can be mechanically compatible with the surrounding bone. That is, the stiffness or modulus of elasticity approximates the host bone. The spacer must be biologically compatible with little spacer/host reactivity or rejection. Finally, an interbody spacer can be radiographically compatible. Metallic spacers are often quite strong and are typically designed to resist compression failure, but are markedly stiffer than the surrounding bone. Today, PEEK (Poly-Ether-Ether-Ketone) spacers are designed to offer better compression resistance while approximating the modulus of elasticity of the host bone. Moreover, PEEK is radiolucent allowing easier post-operative assessment of fusion. Posterior interbody fusion spacers come in a number of shapes. Among the earliest spacers were threaded cylinders. These promote high stability once implanted because of a strong bone implant junction, but also may confer the highest risk of nerve injury during insertion because of their shape. *Data on file at Stryker Spine.

7 Given the frequency of concomitant pedicle screw instrumentation, these large spacers are not mechanically necessary. Vertical cylinders were recommended by Harms for TLIF procedures, but their endplate contact areas are limited thereby limiting maintenance of height and segmental lordosis. Today, most typically rectangular spacers are employed because they are designed to offer the greatest flexibility in insertion. They can be placed unilaterally or bilaterally and from a variety of angles. Geometrically, they are designed to confer outstanding endplate coverage while requiring little nerve root retraction for insertion. Technique Pearls Regardless of the approach, open vs. MIS, TLIF vs. PLIF, a number of technique tips apply in every interbody fusion procedure. First, even when open technique is employed, careful attention to soft tissue handling can help improve posterior muscular function and may decrease pain. Of course, the most important soft tissues are the nerves. Safer posterior lumbar interbody fusion techniques require identification of the exiting and traversing nerves. In TLIF, the exiting root and dorsal root ganglion are identified. In both cases, careful control of local, epidural bleeders through bipolar electrocautery, thrombin soaked gelfoam, or other means will help to allow improved visualization through the critical steps of disc space preparation and spacer instertion. Second, even when an MIS approach is used, an adequate job must be performed mechanically. That is, spacers must be sized to fit the interspace and screws must be sized to fit the pedicle. If, in a given case, full disc space debridement cannot be performed through a less invasive approach, the incision should be opened to ensure that that annular tension is restored and the optimal spacer is implanted. Often, resection of surrounding endplate osteophytes will improve visualization into the disc space to confirm debridement and, subsequently, spacer sizing. Some surgeons prefer to apply bone wax to bleeding bone surfaces in the canal after the spacer has been inserted. Third, a wide near total discectomy must be performed. The disc space around the spacer(s) should be packed with graft material. Fourth, while removal of the endplate cartilage is critical, it is important to protect the bony endplates. Focal disruption of the endplate should result in selection of a new spacer trajectory. Placement of the spacer over a disrupted endplate may lead to early subsidence and a higher risk of spacer migration. Fifth, ideal placement of the spacer(s) in the interspace may vary depending on the patient s needs. For example, if the goal is to maximize segmental lordosis, anterior spacer placement may be preferred. On the other hand, posterior placement may allow for improved foraminal decompression. Conclusions The Stryker AVS PEEK Spacer portfolio is designed to afford the surgeon an excellent tool for stabilization of the anterior column from a posterior approach. This stabilization may be helpful in off-loading posterior instrumentation, increasing foraminal height, or improving spinal alignment. After proper disc space preparation, the AVS Spacer helps to provide a proper geometry for safe insertion while maintaining excellent endplate coverage. Constructed from PEEK, the spacer closely matches the local bone mechanically and allows for visualization during postoperative imaging.

8 Exposure and Preparation of Facet Joints Step 1 Exposure Open Approach A UniLIF procedure can be performed using a standard open or minimally invasive approach, from the patient s left or right side. Typically, cage insertion is performed from the symptomatic side in patients with lumbar radiculopathy. This technique describes a left-sided approach at L4- L5. Figure 1 - Midline incision. The incision is made over the spinous process of L3 and extends to L5. (Fig. 1) Sharp paraspinal dissection is performed exposing the L3-L4 and L4-L5 facets. Care must be taken to avoid damage to the L3-L4 facet capsules. Unless the surgeon intends to perform concomitant intertransverse fusion, the transverse processes need not be exposed. Minimally Invasive Approach The O.I.C system lends itself to minimally invasive approaches as well. MIS systems rely on proprietary retractor systems and specialized tools, the use of which are best depicted in their individual technique guides. A minimally invasive system which can be used is the Stryker Luxor Retractor System. You must refer to the Luxor surgical technique for additional information on minimally invasive exposure. Figure 2 - Prepare the facet joint for fusion by removing the articular cartilage. NOTE: The remaining steps in the surgical technique are similar in both open and minimally invasive surgical approaches. All images in this technique, however, depict an open approach for image clarity. You must refer to the Luxor surgical technique for additional information on minimally invasive approaches and detailed images. Step 2 - Preparation of facet joints Both L4-L5 facet capsules should be removed circumferentially. This is typically accomplished using a cautery device. Bipolar cautery may be useful in achieving hemostasis lateral to the facet joints. The right L4-L5 facet is prepared for fusion by removing the articular cartilage from the facet joint with a burr or other appropriate instrument. (Fig. 2)

9 UniLIF Site Preparation and Distraction Step 3 - UniLIF Site Preparation The UniLIF site preparation is on the left side. An osteotome may be used to help remove the left inferior articular process of L4 with two cuts; a vertical cut just medial to the facet extending superiorly to the superior border of the facet and a horizontal cut directed laterally towards the foramen. Once the two cuts are made, the inferior articulating process of L4 may be removed with a kerrison. (Fig. 3) The left lateral edge of the ligamentum flavum is then visualized. A curette may be used to help release (but not resect) the ligamentum flavum from the superior lamina of L5, helping to allow for distraction. The ligamentum flavum should be preserved when possible, but resection of redundant flavum may be necessary in patients with neurologic compression. Figure 3 - Remove the superior and inferior articular processes. Step 4 - Distraction Effective distraction aids in removal of the superior articular process of L5, decompression of the neuroforamen, preparation of the disc space and insertion of the O.I.C. Cage. This may be accomplished through several techniques: pedicle screw distraction, distraction between boney elements, and/or distraction with a positioning device. If pedicle screw distraction is chosen, the screws should be positioned at this time, using standard technique. (Fig. 4) Apply distraction between pedicle screws placed at L4 and L5. (Fig. 5) Figure 4 - Placement of pedicle screws. Particularly in patients with less than ideal bone quality, it might be useful to size the interspace with paddle distractors, reamerdistractors, or trials before locking the distraction down through the pedicle screws. Interspace distraction helps to give an excellent sense of restoration of annular tension and helps to avoid pedicle screw preloading (which may risk post-operative loosening).

10 UniLIF Site Preparation and Distraction Figure 5 - Place the Pedicle Screw Distractor. Step 4 (Continued) Choices for a supplemental spinal fixation system include, but are not limited to, Stryker Spine pedicle screw and rod or plate systems (Xia, Spiral Radius 90D, Trio, Techtonix, and MANTIS). Please refer to the surgical techniques of the above mentioned Stryker Spine supplemental fixation systems for additional information on implantation. In an open procedure only, apply direct distraction between the boney elements of L4 and L5, such as the spinous processes or laminae. The patient s lordosis can be adjusted with a positioning device, such as a Wilson frame (open and minimally invasive procedures). With sufficient distraction, the L4- L5 foramen will be opened and the entire superior articular process of L5 will be visualized. A small probe may be used to palpate the superior margin of the left L5 pedicle. The superior articular process of L5 should be resected exposing the L4-L5 disc in the L4-L5 foramen. This may be accomplished with an osteotome, rongeur, or other appropriate instrument. Since a consistent leash of veins traverse the foramen over the disc space, the surgeon must be prepared to control bleeding from these veins with bipolar cautery. Hemostasis may be enhanced with topical hemostatic agents and cottonoid pledgets. The exiting L4 nerve root is rostral at this point, under the pars interarticularis, and in many instances is not visible. 10

11 Discectomy and Endplate Preparation Step 5 - Discectomy and Endplate Preparation Access to the disc space is achieved through an annulotomy, made lateral to the posterior longitudinal ligament. Using a scalpel, vertical cuts should be made parallel to the dura and laterally in the foramen from the endplate of L4 to the endplate of L5. Additional cuts should extend horizontally along the endplates of L4 and L5, connecting the vertical cuts. The annulus and any accessible disc material are removed with a pituitary rongeur. (Fig. 6) Commonly, a large osteophyte will protrude inferiorly off the endplate of L4, and sometimes superiorly off the endplate of L5. Sharp excision of these osteophytes with an osteotome or kerrison punch will help to provide a longer entry portal if desired. Figure 6 - Remove the disc with a pituitary rongeurs. Throughout the remainder of the procedure, care must be taken to not damage the remaining lateral, anterior or posterior annulus. A curette or narrow cobb elevator is used to help elevate disc material from the endplates of L4 and L5 on the left lateral side. Next, angled curettes are used to elevate the disc from the endplates of L4 and L5 centrally and on the right side. (Fig. 7) An easily missed portion of the disc lies posteriorly and centrally within the disc space, just ventral to the spinal canal. Special effort should be directed toward removing disc in this zone to help provide optimal surface area for interbody fusion. Straight and up biting pituitary rongeurs should be used to help remove the disc. Additionally, multiple passes with straight and angled curettes may be necessary to help ensure adequate discectomy. Fluoroscopy may help in ensuring clearance of the disc space while limiting the risk of perforation of the ventral, lateral or posteromedial annulus. Figure 7 - Elevate disc material from endplates. 11

12 Sizing the Disc Space and Implant Preparation Figure 8 - Trialing the disc space with PL Trials. Step 6 - Sizing the Disc Space The disc space height is then sized using a series of paddle distractors, reamerdistractors, or trials (Fig. 8). The paddle distractor, reamer-distractor, or trial size is serially increased until the appropriate fit within the disc space is achieved. The paddle distractor, reamer-distractor, or trial should fit snugly within the disc space with distraction released, but care must be taken to not oversize the implant. Undersizing may contribute to a loss of lordosis and inadequate stability for fusion, while oversizing may result in difficult insertion of the implant and disruption of the vertebral boney endplate along with possible graft subsidence. NOTE: The trial footprint is available in all height and width offerings, however, it is only available in a length of 20mm. A ridge exists on the post of the trial at 25mm and 30mm and is designed to assist the surgeon in determining which implant length is appropriate from radiographic images. (Fig. 9) Figure 9 - Determining appropriate implant length in radiographic images. Figure 10 - Cage assembled to the PEEK Spacer Inserter. (O.I.C. PEEK-UniLIF Cage Shown) Figure 11 - Packing graft in the O.I.C cage in the Graft Block using the Graft Compactor. 12 Step 7 - O.I.C. Cage Preparation Select the appropriately sized O.I.C. PEEK, O.I.C. PEEK-UniLIF, O.I.C. PEEK II, or O.I.C. Titanium Cage and assemble it to the appropriate PEEK Spacer Inserter or Cage Impactor. (Fig. 10) NOTE: All O.I.C. PEEK and O.I.C. PEEK-UniLIF cages which are 20, 25, 30, and 33mm in length and 6mm - 8mm in height should be assembled to PEEK Inserter 8, 9. All 8mm and 9mm wide O.I.C. PEEK and O.I.C. PEEK-UniLIF cages which are 9mm - 18mm in height should be assembled to PEEK Inserter 8, 9. All 11mm wide O.I.C. PEEK and O.I.C. PEEK-UniLIF cages which are 20 and 25mm in length and 9mm - 18mm in height should be assembled to PEEK Inserter 11. All 11mm wide O.I.C PEEK - UniLIF cages which are 30 and 33mm in length and 9mm - 14mm in height should be assembled to PEEK Inserter 11. All O.I.C Titanium implants should be assembled to the Titanium Cage Impactor. Place the O.I.C. Cage in the Graft Block and pack it with autogenous graft using the Graft Compactor. (Fig. 11) The compacted graft should be flush with the upper and lower surfaces of the spacer, to later be in contact with the endplates.

13 Cage Insertion Step 8 - O.I.C. Cage Insertion Carefully insert the O.I.C. PEEK, O.I.C. PEEK-UniLIF, or O.I.C. Titanium Cage gently and progressively into the disc space. (Fig. 12) Optimal positioning may be facilitated by directing the implant obliquely until it contacts the ventral annulus. If difficulty is encountered, it most likely represents a mechanical block to passage of the cage. Check for adequacy of the discectomy and be sure distraction is maintained. Then, reposition the cage as needed. Maintain posterior distraction until the implant clears the posterior annulus. The distraction may be released slightly to help facilitate final positioning. Figure 12 - Insert the O.I.C Cage. (O.I.C. PEEK-UniLIF Cage shown) Based on surgeon preference, the PL Impactor may be used to gently tamp the implant to its final position. (Fig. 13) Fluoroscopy may be useful in determining the appropriate trajectory for insertion and appropriate final positioning. NOTE: Difficulty inserting the implant may be related to an inadequate distraction, an undersized annulotomy or oversized implant. Difficulty positioning the implant anteriorly in its oblique orientation and centrally within the disc space may be related to inadequate discectomy or an oversized implant. Figure 13 - Adjust position of the O.I.C Cage. (O.I.C. PEEK-UniLIF Cage shown) The recommended insertion angle for the lordotic O.I.C. PEEK UniLIF implants is approximately 30 off midline. The black circular marker on the lordotic O.I.C. PEEK UniLIF implant is designed to help determine the orientation of the lordosis. To help ensure the lordosis is restored in the desired plane, the black circular marker must be towards the caudal lateral aspects in an oblique insertion. NOTE: To visually confirm the lordosis is restored in the desired plane, the implant must be inserted with the black circular marker towards the caudal lateral aspects in an oblique insertion. Figure 14 - In posterior oblique insertion black circular marker is towards lateral aspect. (O.I.C. PEEK-UniLIF cage shown) 13

14 Placement of Bone Grafting Material 2.5mm Vertical Posterior Marker is 3mm from posterior end 8mm Horizontal Anterior Marker is 3.5mm from tip of anterior nose Figure 15 - Tantalum marker positions. (O.I.C. PEEK-UniLIF implant shown) There are two tantalum markers, oriented perpendicular to each other, embedded within the O.I.C. PEEK and O.I.C. PEEK-UniLIF cages, which are designed to help visually confirm the implant s position under fluoroscopy. One marker is positioned horizontally at the anterior end and the other marker is positioned vertically at the posterior end of the implant. (Fig. 15) In the O.I.C. PEEK and O.I.C. PEEK-UniLIF implants, the vertical posterior marker and anterior horizontal marker will appear as depicted on a radiographic image of an implant centered from left-to-right within the disc space. (Fig. 16 & 17) Figure 16 - Sagittal perspective of a centrally positioned O.I.C. PEEK or O.I.C. PEEK-UniLIF Cage. (O.I.C. PEEK-UniLIF implant shown) Figure 17 - Anterior/posterior perspective of a centrally positioned O.I.C. PEEK or O.I.C. PEEK-UniLIF Cage. (O.I.C. PEEK-UniLIF Cage shown) Step 9 - Placement of Bone Grafting Material Autogenous bone grafting material may be placed lateral, ventral and/ or dorsal to the implanted O.I.C PEEK, O.I.C. PEEK-UniLIF, or O.I.C. Titanium Cage. (Fig. 18) Figure 18 - Place graft around the O.I.C. PEEK, O.I.C. PEEK-UniLIF, or O.I.C. Titanium Cage. (O.I.C. PEEK-UniLIF Cage shown) INTEROPERATIVE RESCUE: The PEEK Spacer Inserter or O.I.C. Cage Impactor can help to rescue the implant if deemed medically necessary. Align the outter chamfered shaft with the contours of the implant and thread the internal shaft into the implant and remove it. The internal shaft alone or a blunt nerve hook may also be used. 14

15 Implant Options O.I.C. PEEK Implants O.I.C. PEEK Implant 0 lordosis LORDOSIS LENGTH WIDTH HEIGHT 0 Degrees 20 mm 9 mm 9 mm - 16 mm 0 Degrees 20 mm 11 mm 9 mm - 16 mm 0 Degrees 25 mm 8 mm 9 mm - 16 mm 0 Degrees 25 mm 11 mm 9 mm - 16 mm O.I.C. PEEK Implant 4 lordosis LORDOSIS LENGTH WIDTH HEIGHT 4 Degrees 20 mm 9 mm 7 mm - 16 mm 4 Degrees 20 mm 11 mm 9 mm - 16 mm 4 Degrees 25 mm 8 mm 7 mm - 16 mm 4 Degrees 25 mm 11 mm 9 mm - 16 mm O.I.C. PEEK Implant 8 lordosis LORDOSIS LENGTH WIDTH HEIGHT 8 Degrees 20 mm 9 mm 9 mm - 16 mm 8 Degrees 20 mm 11 mm 9 mm - 18 mm 8 Degrees 25 mm 8 mm 9 mm - 18 mm 8 Degrees 25 mm 11 mm 9 mm - 16 mm O.I.C. PEEK - UniLIF Implants O.I.C. PEEK - UniLIF Implant 0 lordosis LORDOSIS LENGTH WIDTH HEIGHT 0 Degrees 30 mm 11 mm 6 mm - 14 mm 0 Degrees 33 mm 11 mm 6 mm - 14 mm O.I.C. PEEK - UniLIF Implant 4 lordosis LORDOSIS LENGTH WIDTH HEIGHT 4 Degrees 30 mm 11 mm 6 mm - 14 mm 4 Degrees 33 mm 11 mm 6 mm - 14 mm O.I.C. PEEK - UniLIF Implant 0 lordosis LORDOSIS LENGTH WIDTH HEIGHT 0 Degrees 20 mm 9 mm 9 mm - 16 mm 0 Degrees 20 mm 11 mm 6 mm - 18 mm 0 Degrees 25 mm 8 mm 9 mm - 16 mm 0 Degrees 25 mm 11 mm 6 mm - 18 mm O.I.C. PEEK - UniLIF Implant 4 lordosis LORDOSIS LENGTH WIDTH HEIGHT 4 Degrees 20 mm 9 mm 7 mm - 16 mm 4 Degrees 20 mm 11 mm 6 mm - 18 mm 4 Degrees 25 mm 8 mm 7 mm - 16 mm 4 Degrees 25 mm 11 mm 6 mm - 18 mm NOTE: The lordotic O.I.C. PEEK UniLIF implants in 30 and 33mm lengths, are designed with 4 of oblique lordosis. The recommended insertion angle for the lordotic O.I.C. PEEK UniLIF implants is approximately 30 off midline. Lordotic O.I.C. PEEK and O.I.C. PEEK-UniLIF implants in 20 and 25mm lengths are designed with 4 and 8 of lordosis. These implants are recommended for a traditional PLIF technique. 15

16 Posterior Fusion and Closure Step 10 - Posterior Fusion Since the interbody portion of the procedure is complete, distraction can be released. If pedicle screws were not inserted earlier in the procedure they may now be inserted. Vertical rods are designed to connect the screws together and gentle compression should be applied between the L4 and L5 screws bilaterally. This helps to facilitate restoration of segmental lordosis and compression of the O.I.C. PEEK, O.I.C. PEEK-UniLIF, O.I.C. II, or O.I.C. Titanium Cage and bone graft. Apply appropriate final torque tightening to all screws. The remaining autogenous bone graft may be placed in the decorticated right L4-L5 facet to help promote posteriolateral fusion. (Fig. 18) Intraoperative radiographs should be performed to help confirm satisfactory position of the O.I.C. PEEK, O.I.C. PEEK-UniLIF, or O.I.C. Titanium Cage, pedicle screws, and graft material. Figure 18 - Assemble the rods to the screws and pack the facet with bone graft. Step 11 - Closure Check the left L4-L5 foramen and UniLIF site for any bone fragments or extraneous soft tissue. Once satisfactory decompression of the exiting and traversing nerve roots is confirmed the wound should be closed. 16

17 PEEK Cage Reference Numbers O.I.C. PEEK Cage Ref. Lordosis - 0 Width 9 mm - Length 20mm Description (height x length x lordosis-width) Cage 9x20x Cage 10x20x Cage 11x20x Cage 12x20x Cage 13x20x Cage 14x20x Cage 15x20x Cage 16x20x0-9 Width 11 mm - Length 20mm Cage 9x20x Cage 10x20x Cage 11x20x Cage 12x20x Cage 13x20x Cage 14x20x Cage 15x20x Cage 16x20x0-11 Width 8 mm - Length 25mm Cage 9x25x Cage 10x25x Cage 11x25x Cage 12x25x Cage 13x25x Cage 14x25x Cage 15x25x Cage 16x25x0-8 Width 11 mm - Length 25mm Cage 9x25x Cage 10x25x Cage 11x25x Cage 12x25x Cage 13x25x Cage 14x25x Cage 15x25x Cage 16x25x0-11 Ref. Lordosis - 4 Width 9 mm - Length 20mm Description (height x length x lordosis-width) Cage 7x20x Cage 8x20x Cage 9x20x Cage 10x20x Cage 11x20x Cage 12x20x Cage 13x20x Cage 14x20x Cage 15x20x Cage 16x20x4-9 Width 11 mm - Length 20mm Cage 9x20x Cage 10x20x Cage 11x20x Cage 12x20x Cage 13x20x Cage 14x20x Cage 15x20x Cage 16x20x4-11 Width 8 mm - Length 25mm Cage 7x25x Cage 8x25x Cage 9x25x Cage 10x25x Cage 11x25x Cage 12x25x Cage 13x25x Cage 14x25x Cage 15x25x Cage 16x25x4-8 Width 11 mm - Length 25mm Cage 9x25x Cage 10x25x Cage 11x25x Cage 12x25x Cage 13x25x Cage 14x25x Cage 15x25x Cage 16x25x4-11 Ref. Description (height x length x lordosis-width) Lordosis - 8 Width 9 mm - Length 20mm Cage 9x20x Cage 10x20x Cage 11x20x Cage 12x20x Cage 13x20x Cage 14x20x Cage 15x20x Cage 16x20x8-9 Width 11 mm - Length 20mm Cage 9x20x Cage 10x20x Cage 11x20x Cage 12x20x Cage 13x20x Cage 14x20x Cage 15x20x Cage 16x20x8-11 Width 8 mm - Length 25mm Cage 9x25x Cage 10x25x Cage 11x25x Cage 12x25x Cage 13x25x Cage 14x25x Cage 15x25x Cage 16x25x8-8 Width 11 mm - Length 25mm Cage 9x25x Cage 10x25x Cage 11x25x Cage 12x25x Cage 13x25x Cage 14x25x Cage 15x25x Cage 16x25x

18 Ref. Description (height x length x lordosis-width) Lordosis - 0 Width 11 mm - Length 30mm - UniLIF Cage 6x30x Cage 7x30x Cage 8x30x Cage 9x30x Cage 10x30x Cage 11x30x Cage 12x30x Cage 13x30x Cage 14x30x0-11 Width 11 mm - Length 33mm - UniLIF Cage 6x33x Cage 7x33x Cage 8x33x Cage 9x33x Cage 10x33x Cage 11x33x Cage 12x33x Cage 13x33x Cage 14x33x0-11 Width 8 mm - Length 25mm - UniLIF Vertebral Spacer 9x25x Vertebral Spacer 10x25x Vertebral Spacer 11x25x Vertebral Spacer 12x25x Vertebral Spacer 13x25x Vertebral Spacer 14x25x Vertebral Spacer 15x25x Vertebral Spacer 16x25x0-8 Width 9 mm - Length 20mm - UniLIF Vertebral Spacer 9x20x Vertebral Spacer 10x20x Vertebral Spacer 11x20x Vertebral Spacer 12x20x Vertebral Spacer 13x20x Vertebral Spacer 14x20x Vertebral Spacer 15x20x Vertebral Spacer 16x20x0-9 Width 11 mm - Length 20mm - UniLIF Vertebral Spacer 6x20x Vertebral Spacer 7x20x Vertebral Spacer 8x20x Vertebral Spacer 9x20x Vertebral Spacer 10x20x Vertebral Spacer 11x20x Vertebral Spacer 12x20x Vertebral Spacer 13x20x Vertebral Spacer 13x20x Vertebral Spacer 14x20x Vertebral Spacer 15x20x Vertebral Spacer 16x20x Vertebral Spacer 18x20x0-11 Width 11 mm - Length 25mm - UniLIF Vertebral Spacer 6x25x Vertebral Spacer 7x25x Vertebral Spacer 8x25x Vertebral Spacer 9x25x Vertebral Spacer 10x25x Vertebral Spacer 11x25x Vertebral Spacer 12x25x Vertebral Spacer 13x25x Vertebral Spacer 13x25x Vertebral Spacer 14x25x Vertebral Spacer 15x25x Vertebral Spacer 16x25x Vertebral Spacer 18x25x Ref. Description (height x length x lordosis-width) Lordosis - 4 Width 11 mm - Length 30mm - UniLIF Cage 6x30x Cage 7x30x Cage 8x30x Cage 9x30x Cage 10x30x Cage 11x30x Cage 12x30x Cage 13x30x Cage 14x30x4-11 Width 11 mm - Length 33mm - UniLIF Cage 6x33x Cage 7x33x Cage 8x33x Cage 9x33x Cage 10x33x Cage 11x33x Cage 12x33x Cage 13x33x Cage 14x33x4-11 Width 8 mm - Length 25mm - UniLIF Vertebral Spacer 7x25x Vertebral Spacer 8x25x Vertebral Spacer 9x25x Vertebral Spacer 10x25x Vertebral Spacer 11x25x Vertebral Spacer 12x25x Vertebral Spacer 13x25x Vertebral Spacer 14x25x Vertebral Spacer 15x25x Vertebral Spacer 16x25x4-8 Width 9 mm - Length 20mm - UniLIF Vertebral Spacer 7x20x Vertebral Spacer 8x20x Vertebral Spacer 9x20x Vertebral Spacer 10x20x Vertebral Spacer 11x20x Vertebral Spacer 12x20x Vertebral Spacer 13x20x Vertebral Spacer 14x20x Vertebral Spacer 15x20x Vertebral Spacer 16x20x4-9 Width 11 mm - Length 20mm - UniLIF - UniLIF Vertebral Spacer 6x20x Vertebral Spacer 7x20x Vertebral Spacer 8x20x Vertebral Spacer 9x20x Vertebral Spacer 10x20x Vertebral Spacer 11x20x Vertebral Spacer 12x20x Vertebral Spacer 13x20x Vertebral Spacer 14x20x Vertebral Spacer 15x20x Vertebral Spacer 16x20x Vertebral Spacer 18x20x4-11 Ref. O.I.C. PEEK-UniLIF Cage O.I.C. PEEK-UniLIF Cage Description (height x length x lordosis-width) Lordosis - 4 (Contd.) Width 11 mm - Length 25mm - UniLIF Vertebral Spacer 6x25x Vertebral Spacer 7x25x Vertebral Spacer 8x25x Vertebral Spacer 9x25x Vertebral Spacer 10x25x Vertebral Spacer 11x25x Vertebral Spacer 12x25x Vertebral Spacer 13x25x Vertebral Spacer 14x25x Vertebral Spacer 15x25x Vertebral Spacer 16x25x Vertebral Spacer 18x25x4-11

19 Titanium Cage Reference Numbers Blue 0 Pink 4 Green 8 Ref. Description (height - lordosis) Cage 9-0 length 25 mm Cage 10-0 length 25 mm Cage 11-0 length 25 mm Cage 12-0 length 25 mm Cage 13-0 length 25 mm Cage 9-4 length 25 mm Cage 10-4 length 25 mm Cage 11-4 length 25 mm Cage 12-4 length 25 mm Cage 13-4 length 25 mm Cage 10-8 length 25 mm Cage 11-8 length 25 mm Cage 12-8 length 25 mm Cage 13-8 length 25 mm Cage 14-8 length 25 mm Cage 9-4 length 20 mm Cage 10-4 length 20 mm Cage 11-4 length 20 mm Cage 12-4 length 20 mm Cage 13-4 length 20 mm 19

20 Instrument Set Configuration Reference Description S et Q uantit y Titanium O.I.C. Container for Implants Peek O.I.C. Container for Implants O.I.C. Cages Container for Instruments Triangular Curette Dura Matter Retractor Root Retractors Cage Support Final Impactor Graft Compactor Titanium Cage Impactor Peek Cage Impactor 1 873(109)-(114) Reamer mm 1 873(208)-(214) Distractor mm 1 873(309)-(314) Reamer-Distractor mm 1 20

21 Instrument Set Configuration Reference Description S et Q uantit y PEEK Spacer Inserter PEEK Spacer Inserter Graft Compactor PL Impactor T-handle Graft Block Trial 6 x 20 x Trial 7 x 20 x Trial 8 x 20 x Trial 9 x 20 x Trial 10 x 20 x Trial 11 x 20 x Trial 12 x 20 x Trial 13 x 20 x Trial 14 x 20 x Trial 15 x 20 x Trial 16 x 20 x

22 Instrument Set Configuration Reference Description (height x length x lordosis-width) S et Q uantit y Trial 6 x 20 x Trial 7 x 20 x Trial 8 x 20 x Trial 9 x 20 x Trial 10 x 20 x Trial 11 x 20 x Trial 12 x 20 x Trial 13 x 20 x Trial 14 x 20 x Trial 15 x 20 x Trial 16 x 20 x Trial 6 x 20 x Trial 7 x 20 x Trial 8 x 20 x Trial 9 x 20 x Trial 10 x 20 x Trial 11 x 20 x Trial 12 x 20 x Trial 13 x 20 x Trial 14 x 20 x Trial 15 x 20 x Trial 16 x 20 x

23 Container Set Configuration Reference Description S et Q uantit y Instrument Base Instrument Insert O.I.C. PEEK Cage System Instument Container Lid * O.I.C. PEEK Cage System Implant Container Lid &9mm Wide Implant Tray mm Wide Implant Tray UniLIF Implant Caddy UniLIF Implant Lid UniLIF Implant Caddy UniLIF Implant Caddy Lid ** O.I.C. PEEK II Implant Container Lid O.I.C. PEEK II Implant Container Base , 9mm wide O.I.C. PEEK II Implant Insert mm wide O.I.C. PEEK II Implant Insert 1 * O.I.C. PEEK (ogival nose) associated with O.I.C. PEEK Container. ** O.I.C. PEEK-UniLIF (wedge nose) associated with O.I.C. PEEK II Container. 23

24 INDICATIONS The OIC PEEK Cage is indicated for the treatment of spondylolisthesis, degenerative spine disorders, discal and vertebral instability as well as in cases of spine revision surgery. It is recommended to pack bone graft material inside the implant. The OIC PEEK Cages are to be implanted via posterior approach. The OIC PEEK Cages are intended to be used with supplemental spinal fixation systems that have been cleared for use in the lumbosacral spine (i.e., posterior pedicle screw and rod systems). GENERAL CONDITIONS OF USE The implantation of intervertebral body fusion devices must be performed only by experienced spinal surgeons having undergone the necessary specific training in the use of such systems because this is a technically demanding procedure presenting a risk of serious injury to the patient. CAUTION Based on the fatigue testing results, the physician/surgeon must consider the levels of implantation, patient weight, patient activity level, other patient conditions, etc. which may impact on the performance of the intervertebral body fusion device. The implantation of the intervertebral body fusion device must be performed only by experienced spinal surgeons with specific training in the use of this device because this is a technically demanding procedure presenting a risk of serious injury to the patient. Potential risks identified with the use of this intervertebral body fusion device, which may require additional surgery, include: device component fracture, loss of fixation, pseudoarthrosis (i.e. non-union), fracture of the vertebrae, neurological injury, and vascular or visceral injury. Specialized instruments are provided by STRYKER Spine and must be used to assure accurate implantation of the intervertebral body fusion device. While rare, intraoperative fracture or breakage of instruments can occur, instruments, which have experienced extensive use or extensive force, are more susceptible to fracture depending on the operative precaution, number of procedures, and disposal attention. Instruments must be examined for wear or damage prior to surgery. Instruments for implantation of the O.I.C. PEEK cages are provided non-sterile and must be sterilized prior to use. INFECTION Transient bacteremia can occur in daily life. Dental manipulation, endoscopic examination and other minor surgical procedures have been associated with transient bacteremia. To help prevent infection at the implant site, it may be advisable to use antibiotic prophylaxis before and after such procedures. INSTRUMENTS Specialized instruments are provided by STRYKER Spine and must be used to assure accurate implantation of the device. While rare, intraoperative fracture or breakage of instruments can occur. Instruments which have experienced extensive use or extensive force are more susceptible to fracture depending on the operative precaution, number of procedures, disposal attention. Instruments must be examined for wear or damage prior to surgery. REUSE An implant should never be reused. While it may appear undamaged, a used implant may have acquired blemishes or latent compromise of its integrity which would reduce its service life. Surgeons must verify that the instruments are in good condition and operating order prior to use during surgery. HANDLING Correct handling of the implant is extremely important. The operating surgeon must avoid notching or scratching the device. ALLERGY AND HYPERSENSITIVITY TO FOREIGN BODIES When hypersensitivity is suspected or proven, it is highly recommended that the tolerance of the skin to the materials that make up the implants be checked before they are implanted 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: An active infection at the operative site. Use except as indicated. Marked local inflammation. Any abnormality present which affects the normal process of bone remodeling including, but not limited to, severe osteo porosis involving the spine, bone absorption, osteopenia, primary or metastatic tumors involving the spine, active infection at the site or certain metabolic disorders affecting osteogenesis. Any mental or neuromuscular disorder which would create an unacceptable risk of fixation failure or complications in postoperative care. Open wounds. Pregnancy. Patients having inadequate tissue coverage of the operative site. Any neuromuscular deficit which places an unsafe load level on the device during the healing period. 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. Obesity is defined according to the W.H.O. standards. 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. Foreign body sensitivity. Where material sen sitivity is suspected, appropriate tests must be made prior to material selection or implantation. 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 contra-indications can be relative or absolute and must be taken into account by the physician when making his decision. The above list is not exhaustive. Surgeons must discuss the relative contraindications with the patients. 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 weight bearing, activity levels, and the necessity for periodic medical follow-up. The surgeon must warn the patient of the surgical risks and made aware of possible adverse effects. The surgeon must warn the patient 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 advice 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. Surgeons must advise patients of this fact and warn 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. PREOPERATIVE PRECAUTIONS The surgical indication and the choice of implants must take into account certain important criteria such as: Patients involved in an occupation or activity that applies excessive loading upon the implant (e.g., substantial walking, running, lifting, or muscle strain) may be at increased risk for failure of the fusion and/or the device. Surgeons must instruct patients in detail about the limitations of the implants, including, but not limited to, the impact 24

25 of excessive loading through patient weight or activity, and be taught to govern their activities accordingly. The procedure will not restore function to the level expected with a normal, healthy spine, and the patient should not have unrealistic functional expectations. A condition of senility, mental illness, chemical dependence or alcoholism. These conditions among others may cause the patients to ignore certain necessary limitations and precautions in the use of the implant, leading to failure and other complications. Foreign body sensitivity. Where material sensitivity is suspected appropriate tests must be made prior to material implantation. Surgeons must advise patients who smokehave been shown to have an increased incidence of non-unions. Such patients must be advised of this fact and warned of the potential consequences. Care must be taken to protect the components from being marred, nicked, or notched as a result of contact with metal or abrasive objects. THE CHOICE OF IMPLANTS The choice of proper shape, size and design of the implant for each patient is crucial to the success of the surgery. The surgeon is responsible for this choice which depends on each patient. Patients who are overweight may be responsible for additional stresses and strains on the device which can speed up implant fatigue and/or lead to deformation or failure of the implants. The size and shape of the bone structures determine the size, shape and type of the implants. Once implanted, the implants are subjected to stresses and strains. These repeated stresses on the implants must be taken into consideration by the surgeon at the time of the choice of the implant, during implantation as well as in the post-operative follow-up period. Indeed, the stresses and strains on the implants may cause fatigue or fracture or deformation of the implants, before the bone graft has become completely consolidated. This may result in further side effects or necessitate the early removal of the osteosynthesis device. INTRAOPERATIVE PRECAUTIONS The insertion of the implants must be carried out using instruments designed and provided for this purpose and in accordance with the specific implantation instructions for each implant. Those detailed instructions are provided in the surgical technique brochure supplied by STRYKER Spine. Discard all damaged or mishandled implants. Never reuse an implant, even though it may appear undamaged. POST OPERATIVE PRECAUTIONS Prior to adequate maturation of the fusion mass, implanted spinal instrumentation may need additional help to accommodate full load bearing. External support may be recommended by the physician from two to four months postoperatively or until x-rays or other procedures confirm adequate maturation of the fusion mass; external immobilization by bracing or casting be employed. Surgeons must instruct patients regarding appropriate and restricted activities during consolidation and maturation for the fusion mass in order to prevent placing excessive stress on the implants which may lead to fixation or implant failure and accompanying clinical problems. Surgeons must instruct patients to report any unusual changes of the operative site to his/ her physician. The physician must closely monitor the patient if a change at the site has been detected. ADVERSE EFFECTS Include but are not limited to: Late bone fusion or no visible fusion mass and pseudarthrosis; Peripheral neuropathies, nerve damage, heterotopic bone formation and neurovascular compromise, including paralysis; While the expected life of spinal implant components is difficult to estimate, it is finite. These components are made of foreign materials which are placed within the body for the potential fusion of the spine and reduction of pain. However, due to the many biological, mechanical and physicochemical factors which affect these devices but cannot be evaluated in vivo, the components cannot be expected to indefinitely withstand the activity level and loads of normal healthy bone. Superficial or deep-set infection and inflammatory phenomena; Allergic reactions to the implanted materials although uncommon can occur; Decrease in bone density due to stress shielding; Dural leak requiring surgical repair. Peripheral neuropathies, nerve damage, heterotopic bone formation and neurovas cular compromise, including paralysis, loss of bowel or bladder function, or foot-drop may occur. Cessation of growth of the fused portion of the spine. Loss of proper spinal curvature, correction, height and/or reduction. Delayed Union or Nonunion: Internal fixation appliances are load sharing devices which are used to obtain alignment until normal healing occurs. In the event that healing is delayed, does not occur, or failure to immobilize the delayed/nonunion results, the implant will be subject to excessive and repeated stresses which can eventually cause loosening, bending or fatigue fracture. The degree or success of union, loads produced by weight bearing, and activity levels will, among other conditions, dictate the longevity of the implant. If a nonunion develops or if the implants loosen, bend or break, the device(s) must be revised or removed immediately before serious injury occurs. Neurological and spinal dura mater lesions from surgical trauma; Early loosening may result from inadequate initial fixation, latent infection, premature loading of the device or trauma. Late loosening may result from trauma, infection, biological complications or mechanical problems, with the subsequent possibility of bone erosion, vertebral endplate injury or pain. Serious complications may occur with any spinal surgery. These complications include, but are not limited to, genitourinary disorders; gastrointestinal disorders; vascular disorders, including thrombus; bronchopulmonary disorders, including emboli; bursitis, hemorrhage, myocardial infarction, infection, paralysis or death. Inappropriate or improper surgical placement of this device may cause distraction or stress shielding of the graft or fusion mass. This may contribute to failure of an adequate fusion mass to form. Intraoperative fissure, fracture, or perforation of the spine can occur due to implantation of the components. Postoperative fracture of bone graft or the intervertebral body above or below the level of surgery can occur due to trauma, the presence of defects, or poor bone stock. Adverse effects may necessitate reoperation. Adverse effects may necessitate reoperation or revision. The surgeon must warn the patient of these adverse effects as deemed necessary. IMPLANT REMOVAL If fusion / bone graft growth occurs, the device will be deeply integrated into the bony tissues. As a result, the O.I.C. PEEK cage device is not intended to be removed unless the management of a complication or adverse event requires the removal. Any decision by a physician to remove the device should take into consideration such factors as: The risk to the patient of the additional surgical procedure as well as the difficulty of removal. Migration of the implant, with subsequent pain and/or neurological, articular or soft tissue lesions. Pain or abnormal sensations due to the presence of the implants. Infection or inflammatory reactions. Reduction in bone density due to the different distribution of mechanical and physiological stresses and strains. 25