Rotator cuff bridging repair using acellular dermal matrix in large to massive rotator cuff tears: histologic and clinical analysis.

BACKGROUND: This study investigated the efficacy of the bridging repair using an acellular dermal matrix (ADM) and an ADM with stem cells in rabbits. Also investigated were clinical outcomes of ADM bridging repair for large to massive rotator cuff tears. MATERIALS AND METHODS: ADM, with and without stem cells, was used to cover a 5- × 5-mm-sized cuff defect in 17 rabbits, and biomechanical, histologic, and immunohistochemical analyses were conducted. Also evaluated were 24 patients with large to massive rotator cuff tears after ADM bridging repair. RESULTS: In the biomechanical test, the normal rotator cuff, cuff with ADM plus stem cells, and cuff with ADM in the rabbit model showed a maximum load (N) of 287.3, 217.5, and 170.3 and ultimate tensile strength (N/mm2) of 11.1, 8.0, and 5.2, respectively. Histologically, the cuff tendons with the ADM or ADM plus stem cells showed characteristically mature tendons as time passed. In the clinical study, the mean American Shoulder and Elbow Surgeons score improved from preoperative 50 to postoperative 83, the University of California Los Angeles Shoulder Rating Scale from 17 to 30, and the Simple Shoulder Test from 4 to 8, respectively. No further fatty deteriorations or muscle atrophy were observed on follow-up magnetic resonance imaging. A retear was found in 5 of 24 patients (21%). CONCLUSIONS: Bridging repair with ADM or stem cells in the rabbit model showed cellular infiltration into the graft and some evidence of neotendon formation. Clinically, ADM repair was a safe alternative that did not show any further fatty deterioration nor muscle atrophy in large to massive rotator cuff tears.

Histologic and biomechanical comparison of fascia lata autograft, acellular dermal xenograft, and synthetic patch for bridging massive rotator cuff tear in a rabbit model.

Background: Bridging repair has emerged as a promising and reliable treatment strategy for the massive rotator cuff tears (MRCTs). However, there remains a lack of evidence on which bridging graft provides the better repair results, and a dearth of animal studies comparing bridging repairs with different grafts. The purpose of this study was to evaluate the histological and biomechanical outcomes of commonly used grafts (autologous fascia lata (FL), acellular dermal matrix graft (ADM), and polyethylene terephthalate (PET) patch). Methods: A total of 66 male New Zealand White Rabbits were used to mimic a model of unilateral chronic MRCTs. The rabbits were randomly divided into three groups: (1) FL group, which underwent bridging repair with autologous FL; (2) ADM group, which underwent bridging with ADM; and (3) PET group, which underwent bridging with PET patch. Tissue samples were collected and subjected to histological analysis using Hematoxylin and eosin, Picrosirius red, Safranin O/Fast green staining, and Immunostaining. Collagen diameter and fibril density in the regenerated tendon was analyzed with transmission electron microscopy (TEM). Additionally, biomechanical tests were performed at 6 and 12 weeks after repair. Results: The regenerated tendon successfully reattached to the footprint in all experimental groups. At 6 weeks after repair, the FL group had a significantly higher Modified Tendon Histological Evaluation (MTHE) score at the regenerated tendon than the PET group (13.2 ± 1.64 vs 9.6 ± 1.95, respectively; P = 0.038). The picrosirius red staining results showed that the FL group had a significantly higher type I collagen content than the ADM and PET groups at 6 weeks, and this difference was sustained with the PET group at 12 weeks (P < 0.05). Immunofluorescence analysis against CD68 indicated that the number of macrophage infiltrates was significantly lower in the FL group than in the ADM and PET groups (P < 0.05). At 12 weeks after repair, the area of Safranin O metachromasia was significant greater in ADM group than that in the PET group (P = 0.01). The FL group showed a significantly larger collagen diameter in the regenerated tendon than the PET group (P < 0.05), as indicated by TEM results. Furthermore, the FL group resulted in a greater failure load (at 6 weeks; 118.40 ± 16.70 N vs 93.75 ± 9.06 N, respectively; P = 0.019) and elastic modulus (at 6 weeks; 12.28 ± 1.94 MPa vs 9.58 ± 0.79 MPa, respectively; P = 0.024; at 12 weeks; 15.02 ± 2.36 MPa vs 11.63 ± 1.20 MPa, respectively; P = 0.032) than the ADM group. Conclusions: This study demonstrated that all three grafts could successfully bridging chronic MRCTs in a rabbit model. However, autologous FL promoted tendon regeneration and maturation, and enhanced the tensile properties of the tendon-to-bone complex when compared with ADM and PET grafts.

A composite PET-matrix patch enhances tendon regeneration and tendon-to-bone integration for bridging repair of the chronic massive rotator cuff tears in a rabbit model.

In recent years, bridging repair has emerged as an effective approach for the treatment of massive rotator cuff tears (MRCTs). The objective of this study was to develop a composite patch that combines superior mechanical strength and biocompatibility and evaluate its potential for enhancing the outcomes of bridging repair for MRCTs. The composite patch, referred to as the PET-matrix patch (PM), was fabricated by immersing a plain-woven PET patch in decellularized matrix gel and utilizing the freeze-drying technique. The results demonstrated that the PM has reliable mechanical properties, with a maximum failure load of up to 480 N. The decellularized matrix sponge (DMS), present on the surface of the PM, displayed a loose and porous structure, with an average pore size of 62.51 µm and a porosity of 95.43%. In vitro experiments showed significant elongation of tenocytes on the DMS, with cells spanning across multiple pores and extending multiple protrusions as observed on SEM images. In contrast, tenocytes on the PET patch appeared smaller in size and lacked significant elongation. Additionally, the DMS facilitated the proliferation, migration and differentiation of tenocytes. In a rabbit model of chronic MRCTs, the PM group showed superior outcomes compared to the PET group at 4, 8 and 12 weeks after bridging repair. The PM group displayed significantly higher tendon maturing score, larger collagen diameter in the regenerated tendon and improved tendon-to-bone healing scores compared to the PET group (P < 0.05). Moreover, the maximum failure load of the tendon-bone complex in the PM group was significantly higher than that in the PET group (P < 0.05). In summary, the PM possesses reliable mechanical properties and excellent cytocompatibility, which can significantly improve the outcomes of bridging repair for chronic MRCTs in rabbits. Therefore, it holds great potential for clinical applications.

Application of bridging mesh repair in giant ventral incisional hernia.

Achieving ideal abdominal wall reconstruction in giant ventral incisional hernia has been a challenging for surgeons. This study aimed to verify the safety and efficacy of bridging repair by comparing it with primary fascial closure (PFC) repair in the treatment of giant ventral incisional hernia. We retrospectively analyzed the clinical data of 92 patients with giant ventral incisional hernia who underwent mesh repair at our medical institution from January 1, 2014 to December 31, 2020. Patients were divided into 2 groups: the bridging repair group with 40 patients in whom repair was completed using the bridging technique and the PFC group with 52 patients in whom primary fascial closure was achieved and all patients underwent mesh reinforcement during the operation. The main outcome measures were recurrence rate and morbidity, especially intra-abdominal hypertension (IAH). Follow-up time of both groups lasted at least 24 months after surgery. After a median of 46 months and 65 months of follow-up, respectively, in the two groups, bridging repair did not increase the long-term recurrence rate (2.56%) in the larger defect area group compared to the PFC group (1.96%). There were no significant differences in perioperative morbidity, IAH, incidence of postoperative chronic pain, and sensory impairment of the abdominal wall between both groups. The application of bridging surgery in the treatment of complex giant ventral incisional hernias is safe and effective and does not significantly increase the postoperative recurrence rate.

Reconstruction of irreparable rotator cuff tears with an acellular dermal matrix in elderly patients without joint arthritis.

Background: Reverse shoulder arthroplasty is the mainstay of treatment for symptomatic irreparable rotator cuff tears in elderly patients without arthritis. However, this treatment incurs significant costs and is a major surgical undertaking. This study explores an alternative that involves the reconstruction of irreparable rotator cuff tears using an acellular dermal matrix in elderly patients without established joint arthritis. Methods: We prospectively evaluated the reconstruction of massive irreparable rotator cuff tears in 21 patients aged 68 years and over without radiographic glenohumeral joint osteoarthritis in whom conservative management had failed. A human dermal acellular matrix graft was used as a bridging graft for reconstruction. Pain scores, Oxford Shoulder Scores and ranges of movement were all assessed preoperatively and postoperatively. The mean follow-up period was 5.8 years (range 2.6 to 8.9 years). Results: Statistically significant (p < 0.05) improvements were observed in Oxford Shoulder Scores (mean preoperative score, 21; mean postoperative score, 46), pain scores (mean preoperative score, 6; mean postoperative score, 0) and ranges of movement. Patients also reported a high satisfaction rate with the procedure. Discussion: Human tissue matrix allografts could serve as a suitable option for the treatment of elderly patients with massive irreparable rotator cuff tears without arthritis.

Treatment of massive irreparable rotator cuff tears using dermal allograft bridging reconstruction.

AIMS: Various options are available for treating massive irreparable rotator cuff tears, but all have their own limitations and no gold standard currently exists. Our aim was to report on outcomes of bridging repair with a dermal allograft for symptomatic massive irreparable rotator cuff tears where primary or partial repair was not possible. PATIENTS AND METHODS: We prospectively reviewed 22 patients who underwent an open interposition bridging repair with an allograft (GraftJacket) sutured medially to the residual rotator cuff stump and laterally to the footprint with suture anchors. Mean age at time of surgery was 59 years (range 53-66 years). The Oxford Shoulder Score, pain visual analogue scale and range of motion were compared pre-operatively and at mean follow up of 2.8 years. All patients had a postoperative MRI scan. RESULTS: There was a significant improvement in mean Oxford Shoulder Score from a pre-operative score of 14.2-34.3 points (p < 0.01) at final follow up. Pain VAS score improved from 6.6 points to 2.8 points (p < 0.05). Significant improvements in range of motion were also seen. Postoperative MRI scans showed a retear in 8 patients (36%), but the retear size was smaller and an improvement in outcomes maintained at final follow up. CONCLUSION: Open dermal allograft bridging repair for massive irreparable rotator cuff tears can lead to satisfactory outcomes and delay the need for a reverse shoulder arthroplasty.

Failed Dermal Allograft Procedures for Irreparable Rotator Cuff Tears Can Still Improve Pain and Function: The "Biologic Tuberoplasty Effect".

BACKGROUND: Acellular dermal matrices (ADMs) have been used in the treatment of shoulders with massive rotator cuff tears (MRCTs). Despite clinical improvement, correlation of clinical findings with ADM integrity on imaging has not been investigated. HYPOTHESIS: The pain in shoulders with MRCTs is partially due to bone-to-bone contact between the tuberosity and acromion. Coverage of the tuberosity with an intact graft or a graft that is torn in a way that the tuberosity remains covered will act as an interpositional tissue, preventing bone-to-bone contact and leading to clinical improvement. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 2006 and 2016, a total of 25 shoulders with MRCTs underwent a procedure with an ADM. Pre- and postoperative visual analog scale (VAS) results, American Shoulder and Elbow Surgeons (ASES) score, Hamada grade, and Goutallier classification were reviewed. A postoperative magnetic resonance imaging (MRI) was obtained in 22 (88%) shoulders. The status of the graft was divided into the following categories: type I, intact graft; type II, graft tear with tuberosity covered; and type III, graft tear with tuberosity uncovered (bare). RESULTS: The mean patient age was 61 years (range, 49-73 years), and the mean follow-up was 25.6 months (range, 10-80 months). Mean length from surgery to postoperative MRI was 13.9 months (range, 6-80 months). The graft was torn in 59% (13/22 shoulders). Significant improvements were found in VAS and ASES scores (7 vs 0.7 and 32.6 vs 91.2, respectively; P < .01) for type I grafts and in VAS and ASES scores (8.1 vs 1.3 and 26.3 vs 84.6, respectively; P < .01) for type II grafts. No difference was found in postoperative VAS and ASES (0.7 vs 1.3 and 91.2 vs 84.6, respectively; P = .8) between type I and type II grafts. No improvement was seen in VAS (7.3 vs 5.7; P = .2) or ASES (30.6 vs 37.2; P = .5) for type III grafts. CONCLUSION: MRI appearance of the graft has a significant impact on functional outcomes. Patients with an intact graft or a graft tear leaving the tuberosity covered have lower pain and higher functional scores than those in whom the torn graft leaves the tuberosity uncovered.

Outcome of partial repair of massive rotator cuff tears with and without human tissue allograft bridging repair.

BACKGROUND: The surgical management of massive rotator cuff tears remains a challenge. It is suggested that, even in a massive tear that appears irreparable, attempting to repair it as much as possible can be helpful in improving functional outcomes. However the results can be short term and variable. The purpose of our study was to determine if human tissue allograft bridged repair of massive irreparable rotator cuff tears to achieve a complete repair produces similar outcomes compared to partial repair alone. METHODS: We prospectively reviewed outcome scores in 13 patients who underwent partial repair alone for massive irreparable rotator cuff tears and compared them to 13 patients who had partial repairs bridged with allograft. Oxford and Constant scores were compared pre-operatively and at a minimum follow-up of 2 years (range 2 years to 5 years). RESULTS: The mean improvement in the Constant score at final follow-up compared to pre-operative scores was 27.7 points in the partial repair group and 42.8 points in the allograft group (p < 0.01). The Oxford Shoulder Score improved mean of 19.3 points in the partial repair group and 29 points in the allograft group (p < 0.02) at 2 years. CONCLUSIONS: Human tissue matrix allograft provides a better outcome for open bridging of irreparable rotator cuff tears than partial repair alone.