35 Acellular Human Dermal Allograft Rotator Cuff Reconstruction

Michael Bahk, Stephen Snyder, and J. Ryan Taylor

Summary

Large and massive rotator cuff tears with retraction present a challenge for adequate repair. We present the use of dermal allograft to assist with arthroscopic rotator cuff repair and reconstruction to the native footprint.

Keywords: dermal allograft, massive rotator cuff tear, arthroscopic repair

35.1 Patient Positioning

Please refer to the chapter 2 on SCOI Row Rotator Cuff Repair for patient positioning.

35.2 Portal Placement

Please refer to the chapter 2 on SCOI Row Rotator Cuff Repair for techniques in identifying bony landmarks and for portal placement. Sequence of portal placement is described in the surgical technique below.

35.3 Surgical Technique

35.3.1 Preoperative Preparation (Back Table)

? Tie 12 short-tailed interference knot (STIK) sutures using three different colors of #2 braided suture. The STIK knots are made by wrapping a suture once around a 2-mm metal rod (switching stick) and tying a bulky knot at the end. The small loop created near the knot will facilitate grasping of suture when retrieving for tying.

? Make a knotted measuring suture, spaced with 1 cm increments on a 0 braided suture with a STIK loop at one end. Color every other knot with a surgical marker with a total of five knots (5 cm). The knotted measuring suture is then loaded though a knot pusher with the free loop end held with the grasper for ease in measuring the defect via another portal.

? Hydrate the graft in room temperature saline if necessary once it is certain it will be used.

35.3.2 Shoulder Arthroscopic Evaluation, Debridement, Decompression, and Preparation

? Create a standard posterior midglenoid portal (PMGP) and anterior midglenoid portal (AMGP) and place a 7-mm docking cannula in each one (DryDoc 2 � 95 mm, Conmed/Linvatec, Largo, FL). These ?docking? cannulas will remain in these portals for the entire case.

? Perform a 15-point arthroscopic evaluation of the shoulder, documenting the condition of the rotator cuff, biceps tendon, labrum, cartilage surfaces, subscapularis, and synovium.

? Debride the degenerative edges of the cuff and thickened bursal scar. Mobilize the medial stump of the rotator cuff by carefully releasing the scar and capsule at the level of the glenoid. If needed, repair any significant subscapularis or labral pathology.

? Continue preparation of the bursal space by smoothing the undersurface of the acromioclavicular(AC) joint. All remaining suture material or anchor should be removed if they are obstructing bone needed for graft placement. Use the motorized shaver to lightly debride the greater tuberosity and the biceps groove leaving the cortex intact to induce healing of tendon and graft to bone.

? Use a spinal needle 3?4 cm lateral from the acromial edge on the lateral deltoid to localize the midpoint of the cuff defect (this is not always at the midpoint of the acromion) to create the midlateral subacromial portal (MLSAP). Insert a larger, 8-mm docking cannula in this portal (8 � 75 mm ?red? DryDoc cannula). If the cuff defect is found to be greater than 3.5 cm, then a 10-mm cannula with an external rubber diaphragm is recommended (Smith & Nephew, Andover, MA).

? Create a suprascapular portal by making a small stab incision though the skin at the soft spot of the suprascapular fossa, just posterior to the AC joint. A spinal needle is used to identify proper placement of the portal. The shaver is then used to remove soft tissue below the suprascapular notch for better visualization of the portal. This portal is used to retrieve and store free ends of medial STIK sutures after they are passed though the top of the cuff stump. This facilitates pulling the graft into the shoulder and lessens the chance of twisting sutures.

35.3.3 Placement of First Suture Anchor

? With the scope in the MLSAP at the 50-yard line of the tear, a spinal needle is used as a guide to identify the proper position of the first anchor.

? The ideal position is a few millimeters anterior to the posterior edge of the cuff stump and 5 mm lateral to the edge of the articular cartilage.

? Prior to inserting the anchor, a small 2-mm bone punch is used to create a starter hole, as well as five to nine ?bone marrow vents? by puncturing the exposed bone of the lateral tuberosity (away from the anchor sites).

? Insert a triple-loaded suture anchor into the pilot hole using a medial ?tent peg? angle, seating the anchor 2 mm below the surface of the cortex.

? Pass the medial limb of the posteriormost suture from the posterior anchor through the edge of the posterior cuff near the attachment site on the bone to accomplish a ?partial cuff repair,? taking care not to place any tension on sutures when they are tied.

? This can be accomplished using a suture shuttle technique, by first retrieving the medial limb of the posterior most suture into the AMGP. A crescent-shaped suture hook is used to pass the shuttling suture through the cuff stump via the posterior midglenoid (PMG) cannula. The shuttle suture is then retrieved into the anterior midglenoid (AMG) cannula with the grasper, and the suture is loaded and carried back through the cuff and out the PMG cannula. The suture is tied using a sliding-locking knot.

? Clamp the remaining sutures outside the skin to hold them snug.

35.3.4 Placement of Second Anchor and Performing the Biceps Tenodesis Using the ThRevo ?Italian Loop? Method

? The curette and shaver are used to ?freshen? the biceps groove by removing the cartilage and synovial tissue. Three bone marrow vents are created in the groove leaving 5 mm of bone between each hole.

? Use the spinal needle to guide placement of the anterior anchor. The anchor is placed 5 mm lateral to the articular cartilage and a few mm posterior to the biceps tendon.

? The most anteromedial suture limb is retrieved out the PMG cannula with the crochet hook.

? A suture hook is then used via the AMG cannula to traverse any substantial tissue from the rotator interval and pass through the center of the biceps tendon at the same level as the anchor. The shuttle is carried out the PMG portal, where the suture is loaded and carried back though the biceps and rotator interval tissue out the AMG cannula. The same suture is again retrieved out the PMG cannula. The same process is again repeated with the suture hook a few millimeters from the initial pass obtaining a second robust bite of tendon and using the shuttle to carry the same suture back out the AMG portal, completing the ?Italian loop? stitch. A nonsliding Revo knot is then used to complete the biceps tenodesis.

? One of the remaining sutures can be used to suture the anteriormost edge of the supraspinatus tendon. The sutures are tied.

? The remaining suture from the anchor is clamped outside of the skin for later use.

35.3.5 Measuring the Defect in the Rotator Cuff

? Graft size is measured in both anterior-to-posterior and medial-to-lateral dimensions using a knotted measuring suture, spaced in1 cm increments. The knotted measuring suture is loaded though the eye of a knot pusher such that the free loop is on the tip inserted into the anterior cannula.

? The knotted measuring suture is used to measure between the two lateral suture anchors from the center of the cuff tendon stump to the edge of the humeral head cartilage.

? The graft should be oversized by 3 mm per side to ensure coverage of the defect.

? The corresponding measurements are then drawn on a towel using a surgical pen to create a pattern for cutting the allograft.

35.3.6 Preparation of the Graft (Back Table)

? A surgical assistant prepares the graft on the back table.

? Press the moist graft into the pattern that was drawn on the towel to transfer the pattern to the graft.

? Dermal allografts have a basement membrane ?smooth? side and a reticular ?fuzzy? side. Dimensions are drawn and knots set on the basement membrane side, while the reticular side is oriented down over the tendon/bone.

? The graft is cut sharply over a metal surface to ensure no fabric fibers are introduced into the specimen.

? Draw a 1-cm centerline in the middle of the lateral edge to orient the graft.

? Mark dots for STIK suture placement 5 mm from the edge of the graft and 6 mm apart on the posterior, medial, and anterior boarders. Place a dot at the antero- and posterolateral corners for placement of the remaining suture from the posterior and anterior anchors.

? Place a STIK suture at each anterior and posterior mark using a Keith needle so that the loop and knot are on the basement membrane (shiny) side. The two most lateral corners are left open.

? Use white suture for the medial STIK sutures, coloring every other suture with a surgical pen for easy identification when passing and tying.

? Alternate dark green and light green for the anterior and posterior STIK sutures.

? Ensure the graft remains hydrated with normal saline throughout the preparation process.

35.3.7 Attachment of the Graft to the Posteromedial Cuff

? Wrap a moistened surgical towel around the arm lateral to the MLSA cannula and secure it with a clamp. Orient the graft on the towel anatomically, rotated 45� posteriorly. Use an Alice clamp to secure the STIK suture tails to the towel in an orderly manner. This step is critical, as each successive suture must pass parallel and anterior to the previous suture. If any of the sutures twist or cross, the graft will twist when it is brought into the shoulder, making it extremely difficult to complete the case.

? To begin the graft passing process, first retrieve the medial limb of the center suture from the posterior anchor and out the MLSA cannula, ensuring the suture passes medial to the ?suture stack? and between the suture anchors.

? Use a Keith needle to pass the retrieved medial suture through the graft from bottom to top at the posterolateral corner mark. Tie a STIK knot on the top of the graft to match the other previously placed STIK knots.

? Keep the remaining sutures from the posterior anchor taut outside of the skin with a hemostat clamp.

? Select and clamp the free end of the most posterolateral STIK suture from the graft, and clamp through an Alice clamp on the posterior aspect of the towel. This is referred to as ?staging the suture?(i.e., preparing it to be next to pass).

? A crescent suture hook is then used to pass a shuttle suture though a healthy bite of posterior cuff, 6 mm medial to the posterior anchor. The suture is retrieved from the MLSA cannula anterior to the previously passed suture from the anchor and between the ?suture stacks? from the remaining anchor sutures held outside the skin with hemostat clamps. Load the shuttle and carry it back though the cuff and though the PMG cannula.

? Repeat this process with the crescent suture hook, passing the STIKs along the posterior edge, toward the medial aspect of the cuff defect, spacing the sutures 6 mm apart. Store the ends of the sutures inside the posterior cannula.

35.3.8 Alternative Method?Direct Suture Passing

? The ?direct pass? method via the lateral portal is preferred by some surgeons. This can be accomplished by passing the free ends of the STIK sutures sequentially, starting from the posterior aspect of the defect, moving to the medial stump and then to anterior, with a direct pass suture needle device. Great care must be taken not to cross the sutures during this process. When using the suture shuttle method, the needle is inserted into the PMAC and sutures are passed from posterior medial to anterior medial. As you progress medially along the cuff stump, use the appropriate suture needle with a shuttle, usually a 45� right or left hook and sometimes using a 60� or 90� hook needle. It is usually best to pass four medial sutures to ensure a firm hold of graft to cuff stump.

? The first medial suture is passed just posterior to the scapular spine, the second just anterior to the spine and the other two through a healthy bite of the supraspinatus tendon beneath the distal clavicle.

? The free ends of the white medial STIK sutures can be brought out of the suprascapular notch portal using a circle grasper to help avoid entanglement.

35.3.9 Attachment of the Graft to the Anterior Cuff and Biceps Tendon

? With the scope in the PMGP or accessory posterolateral portal, use an appropriately curved suture hook though the AMG cannula to continue progression from the medial to the anterior aspect of the cuff defect. Use the same method as was done posteriorly. Pass the suture hook anterior to the anchor ?suture stack? and retrieve the shuttle with the grasper posterior to it, out of the MLSA cannula. Each suture is then shuttled though the cuff back out the AMG cannula. Each STIK suture should be passed with 6 mmof space between them. Often, the anterior edge defect requires incorporation of tissue from the coracohumeral ligament, rotator interval, and biceps tendon but seldom the superior edge of the subscapularis tendon.

? Remember to proceed carefully to not cross any suture, always retrieving the shuttle suture ?anterior? and parallel to previously passed sutures.

? As you continue to progress along the anterior edge, incorporating rotator interval tissue (and biceps if needed). Leave the free end of the STIK sutures in the AMG cannula.

? Retrieve the medial end of the middle suture from the anterolateral anchor and carry it out the MLSA cannula, to any other sutures from the anchor, to avoid twisting. This suture is passed though the anterolateral corner of the graft from bottom to top using a Keith needle. A STIK loop is tied on top of the graft. Remove the slack from the suture and clamp the end outside the skin.

35.3.10 Deliver the Graft into the Shoulder Joint

? Orient the graft so the medial edge is directly adjacent the MLSA cannula. Pull the free ends of all the STIK knot sutures to ensure all of the sutures are free of slack and all equally tensioned in their respective portal/cannula.

? Roll the graft so that the knots are inside.

? Continue to gently pull on white and white/purple suture tails exiting the suprascapular notch portal to bring the graft inside the MSLA cannula. In a stepwise fashion, alternate pulling the other suture tails to take up any slack while traveling down the cannula into the shoulder. This will avoid any loops in the sutures from catching around the STIK knots and causing the graft to seat improperly.

? Retrieve all the sutures tails stored in the PMG cannula into the AMG cannula except for the most posterolateral STIK. Retrieve the knotted/looped end of this STIK though the PMG cannula and tie the suture ends with a sliding-locking knot and three half hitches using the non-knotted end as the post.

? Continue tying the posterior STIK sutures using the same method, one at a time, working medially, then anteriorly.

35.3.11 Tying of the Remaining Sutures from the Anchors

? With the scope in the MLSAP, retrieve both ends of the anterior anchored suture that passes though the anterolateral aspect of the graft, through the AMG portal. Cut off the knot and use the looped/knotted end as the post and tie with a sliding-locking knot.

? Repeat the process on the posterior anchor to secure the posterolateral corner of the graft.

35.3.12 Suturing the Lateral Graft to Bone

? Retrieve the medialmost remaining suture from the posterior anchor through the AMG cannula. Use the PMG cannula to pass a curved suture hook from top to bottom, 5 mm anterior to the previous suture. Retrieve the other end of the suture and store them in colored plastic suture protectors (Suture Saver, Conmed/Linvatec) outside the PMG cannula. Repeat the stitching for the anteriorly anchored suture and store it outside the AMG cannula also in a Suture Saver.

35.3.13 Insert Third/Fourth Anchors

? Most repairs only require one additional anchor at the lateral aspect of the graft. If there is more than 1 cm on each side of the centerline, two double-loaded anchors are required. Use the Revo punch to create small bone vents lateral to the anchor site.

? If only one anchor is required, place it directly lateral to the midlateral mark on the graft.

? Pass the sutures though the graft from posterior to anterior, and store each in a Suture Saver outside the PMG cannula.

35.3.14 Tying the Anchored Sutures

? Retrieve the sutures stored in the Suture Savers into the lateral cannula from an anterior-to-posterior direction using a crochet hook.

? Using sliding-locking knots, tie the sutures through the lateral portal so that the knots are on top of the graft.

35.3.15 Evaluate the Repair

? Carefully document the repair, looking for any gaps along the edges. If a gap is identified, pass additional suture with a suture hook, using the suture shuttling method.

? Once the security of the repair is verified, turn off the pump to observe bone marrow vents, which will produce the ?Crimson Duvet? or super clot of red/bone marrow cells covering the graft and lateral tuberosity. These cells bring a new blood supply that will form a rich matrix replete with platelets, their growth factors, and mesenchymal stem cells (? Video 35.1).

35.4 Surgeon Tips and Tricks

? Patient should have good passive and active assisted motion of the shoulder with minimal arthritis. Preoperative active range of motion is the best predictor of postoperative subjective success.

image

Video 35.1 Surgical demonstration of acellular human dermal allograft rotator cuff reconstruction.

? The operation should be practiced on a cadaver and ALEX model lab (Sawbones, Vashon, WA) until the steps are second nature for the surgeon and staff.

? Take care to debride tissue that might obstruct visualization and obtain good hemostasis.

? The patients should understand that, even when completely successful, this operation will never result in a ?normal? shoulder. There will always be subjective weakness, especially with external rotation.

? Never suture the graft in tension. Stitch placement within the shoulder must be accurate, and closely reapproximate the position of the STIK sutures on the graft for the graft to spread out evenly. When the arm rests in the sling post-op, gravity will add some tension to the graft/cuff construct to help align the physiological stresses that will help maturation. As the graft is repopulated with host cells, it will attain a more tendon-like tone, and elasticity will decrease.

? Pay close attention to positioning the patient for surgery. Prolonged surgical time adds an increased risk for external pressure to skin and nerves.

? The operating surgeon and the assistant must be comfortable using the scope in all three subacromial portals.

? ?Stay anterior?: Pay close attention with each pass through though the lateral cannula to always stay anterior to the previously passed suture.

? Avoid slack in the sutures when pulling the STIK sutures into the shoulder by pulling the medial sutures first and taking up the slack in all others.

? The amount of time that goes into preoperative patient counseling is significant. Patients must understand that there will be a prolonged recovery time and that this surgery is a ?salvage? operation to try to reduce pain, improve function, and avoid the need for a reverse shoulder prosthesis.

? Always direct the punch used for the vents vertically down the humerus and thus away from the subchondral bone area where the anchors will be seated and leave a 5 mm bridge of cortical bone between the vents.

35.5 Pitfalls/Complications

? Complications for this procedure are rare. The average operative time is increased approximately 1hour when compared to standard repair of a massive rotator cuff repair, theoretically increasing the risk for transient neuropraxia and infection.

? All graft material is not alike. The rotator cuff graft must be chosen with care. Our graft of choice in symptomatic patients with chronic, nonrepairable rotator cuff defects and minimal arthritis is a human acellular dermal matrix allograft that is 2.8 to 3.2 mm in thickness. We prefer a prehydrated product. This acellular human dermal matrix is extremely strong, free from cells, but rich in collagen, elastin, and preserved blood vessel channels as well as growth factors. We find this extracellular matrix, superior to other biologic matrices currently available.

35.6 Postoperative Care

? Immobilization sling with 15� abduction pillow (UltraSling IV ER, DJO Global, Carlsbad, CA). Immediately postoperatively, begin elbow, wrist, and hand exercises and isometric scapula shrugs. Begin small pendulum circles at 1 week postoperatively.

? Initiate formal physical therapy at 8 weeks after surgery. The program followed is intentionally slow, and progress, similar to that of a massive repairable cuff tear. We encourage pool therapy at 6?8 weeks to allow passive motion without stress on the healing graft.

? Progress activities at 2 months with active assisted lifting.

35.7 Rationale and/or Evidence for Approach

35.7.1 Methods

One hundred and six patients with 109 shoulders were treated with anacellular human dermal allograft reconstruction for a massive nonrepairable rotator cuff tear between March 4, 2003 and July 26, 2011. Many of these patients were evaluated at 3months and 1year postoperatively with an intraarticular gadolinium-enhanced magnetic resonance imaging (MRI). Two orthopedic surgeons and a musculoskeletal radiologist evaluated the MRI arthrograms to determine the status of the graft. These patients also completed a visual analog pain scale (VAS), simple shoulder test (SST), and modified University of California at Los Angeles shoulder scores preoperatively and at multiple time points postoperatively. Data were collected at 3 months, 1 year, and 2 years after the procedure. Many of the patients had late follow-up between 2 and 7 years postoperatively.

35.7.2 Results

? The 3-month postoperative MRI evaluations demonstrated that 85% (90/106) of patients had intact allografts, 15% (16/106) of patients had a tear, and three patients did not undergo the MRI.

? At 1 year postoperatively, 74% (46/62) of the previously intact reconstruction patients had intact allografts, while the other 26% (16/62) were found to have a new tear. Forty-seven did not undergo further advanced imaging.

? Preoperative outcome surveys were collected from 103 patients. Postoperative surveys were collected from 65, 53, 20, and 51 patients at the 3-month, 1-year, 2-year, and greater than 3-year follow-up, respectively. The SST significantly improved from a preoperative average of 6.2 to a postoperative score of 6.79, 9.37, 10.57, and 10.9, respectively, at 3-month, 1-year, 2-year, and greater than 3-year follow-up (all P < 0.001).

? UCLA scores significantly improved from 14.56 preoperatively to 23.34, 28.10, 30.4, and 28.78 at 3-month, 1-year, 2-year, and greater than 3-year follow-up, respectively (all P < 0.001).

? VAS scores improved from 3.3 preoperatively to 1.64, 1.01, 0.95, and 1.22 at 3-month, 1-year, 2-year, and greater than 3-year follow-up, respectively (P < 0.001 preoperatively compared with all postoperative time periods).

? Constant scores averaged 76 for patients at the final follow-up (> 3 years) (20).

35.7.3 Conclusion

We believe that certain types of acellular matrix allograft tissues are a viable option for surgical salvage in select cases of nonrepairable, massive, rotator cuff tears. Our evidence for this is based on our own studies, experience, as well as the research of others that have documented similar outcomes to those of our own. Of course, longer followup and more cases are essential to determine the longevity and viability of the graft as well as patient satisfaction. Arthroscopic techniques permit us to treat the entire joint, including biceps, subscapularis, labrum, synovium, etc., without damage to the deltoid or large skin incisions in an outpatient setting.

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