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1.
J Hand Surg Am ; 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32359866

RESUMO

Peripheral nerve injuries (PNI) are common and frequently afflict otherwise healthy individuals after traumatic or iatrogenic events. Adjuvant therapies to improve functional outcomes after surgical repair of PNI have been investigated extensively in preclinical studies; however, to date, none have been clinically proven to have a notable therapeutic effect. FK506 (tacrolimus), a US Food and Drug Administration-approved systemic immunosuppressant, has demonstrated promising neuro-regenerative properties in both animal studies and clinical reports, but its adverse effects when systemically administered have precluded its broader applicability for patients with PNI. Recent advances in bioengineered drug delivery systems have made local FK506 delivery to a site of PNI an intriguing method of promoting peripheral nerve regeneration, with promising results in preclinical translational investigations. This review summarizes the preclinical and clinical evidence for FK506's beneficial effect in promoting peripheral nerve regeneration when administered systemically and locally.

3.
BMJ Case Rep ; 13(5)2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32381527

RESUMO

We report a patient who has been on tacrolimus for bilateral lung transplantation and presented with a brachial plexus injury (BPI), with unusual improvement of lower trunk innervated hand function. The lower trunk injury with resultant left hand paralysis had developed after his sternotomy 18 months ago. He has been treated with tacrolimus as part of his immunosuppression protocol since the surgery, without severe side effects. Physical examination at 18 months demonstrated unusual excellent grip pattern and full opposition of his thumb with slight claw deformity of his ulnar two digits. While the neurotoxic effects of tacrolimus are more emphasised, the neuroregenerative properties have been recently explored. The recovery in this patient is unique and unusual after BPI and is most likely as a result of the low dose tacrolimus treatment.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32418840

RESUMO

BACKGROUND: When direct nerve coaptation is impossible after peripheral nerve injury, autografts, processed allografts, or conduits are used to bridge the nerve gap. The purpose of this study was to examine if human adipose-derived Mesenchymal Stromal/Stem Cells (MSCs) could be introduced to commercially available nerve graft substitutes and to determine cell distribution and the seeding efficiency of a dynamic seeding strategy. METHODS: MTS assays examined the viability of human MSCs after introduction to the AvanceⓇ Nerve Graft and the NeuraGenⓇ Nerve Guide. MSCs were dynamically seeded on nerve substitutes for either 6, 12, or 24 h. Cell counts, live/dead stains, Hoechst stains, and Scanning Electron Microscopy (SEM) revealed the seeding efficiency and the distribution of MSCs after seeding. RESULTS: The viability of MSCs was not affected by nerve substitutes. Dynamic seeding led to uniformly distributed MSCs over the surface of both nerve substitutes and revealed MSCs on the inner surface of the NeuraGenⓇ Nerve Guides. The maximal seeding efficiency of NeuraGenⓇ Nerve Guides (94%), obtained after 12 h was significantly higher than that of AvanceⓇ Nerve Grafts (66%) (p = 0.010). CONCLUSION: Human MSCs can be dynamically seeded on AvanceⓇ Nerve Grafts and NeuraGenⓇ Nerve Guides. The optimal seeding duration was 12 h. MSCs were distributed in a uniform fashion on exposed surfaces. This study demonstrates that human MSCs can be effectively and efficiently seeded onto commercially available nerve autograft substitutes in a timely fashion and sets the stage for the clinical application of MSC-seeded nerve graft substitutes clinically.

5.
Plast Reconstr Surg ; 2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-32459734

RESUMO

BACKGROUND: We sought to determine the reliability of the Soong classification, which relates the position of the implant to the watershed line of the distal radius, for predicting flexor tendinopathy in distal radius fractures treated with volar plate fixation. METHODS: Medical records were reviewed, including: demographics, fracture and operative characteristics, tendon-related complications, and radiographic outcomes. 659 distal radius fractures were reviewed with a mean duration of clinical follow-up of 12.9 ± 0.7 months. RESULTS: The incidence of isolated flexor tendinopathy and tendon rupture was 0.9% and 0.3%, respectively. Soong classification failed to independently predict flexor tendon rupture or tendinopathy. Fractures classified as inadequately reduced were significantly associated with Soong grade 0 or grade 2, whereas adequately reduced fractures were significantly associated with Soong grade 1. CONCLUSION: The Soong Classification is not the sole predictor of flexor tendinopathy and may be viewed as a reflection of the overall appropriateness of fracture reduction.

6.
Tech Hand Up Extrem Surg ; 24(2): 53-54, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32282615
7.
Gene ; 747: 144627, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32224270

RESUMO

BACKGROUND: Bone allotransplant viability can be maintained long-term by implanting arteriovenous (AV) bundles and creating an autogenous neoangiogenic circulation. Only short-term immunosuppression is required. This study investigates the origin of viable osteocytes observed in areas of active bone remodeling in orthotopically transplanted tibiae in a Yucatan mini-pig model. METHODS: Segmental tibial defects created in female Yucatan minipigs (N = 14) were reconstructed with a matched vascularized composite allotransplant from a male donor. The circulation was microsurgically restored, with simultaneous autogenous AV-bundle implantation in group 1 (N = 7). A ligated AV-bundle was implanted as a no-angiogenesis control in group 2 (N = 7). After 20-weeks, repopulation of the allotransplant was assessed by real-time qPCR measurement of relative copy numbers of a Y chromosome-specific gene (SRY) and an autosomal housekeeping gene, ribosomal protein L4 (RPL4). A lower SRY/RPL4 ratio demonstrates replacement of male allogeneic cells with female, autogenous cells in the sample. Genomic DNA was extracted from cross-sections of the allotransplant, liver and spleen. Additionally, areas of new bone formation within the allotransplant were sampled by laser capture microdissection. A comparison was made between groups as well as male control samples. RNA was extracted from bone as well, as a measure of metabolically active cells. RESULTS: Laser-captured areas of new bone formation in animals with both normal and ligated AV-bundles were found to have significantly lower relative copy numbers of SRY (p = 0.03) than control specimens from male bone, indicating replacement by female (autogenous) bone-forming cells. Analysis of an entire segment of the allotransplant from Group 1 was similarly reduced (p = 0.04), unlike that from Group 2. RNA expression of SRY was observed in both groups. No chimerism could be found in non-bone tissues (liver and spleen). CONCLUSION: We observed a significant level of transplant chimerism in areas of new bone formation sampled by laser capture microdissection. The migration of autogenous cells including osteocytes was seen in both groups. Survival of some allogeneic (male) cells was also demonstrable. No microchimerism was found in liver and spleen.


Assuntos
Transplante Ósseo , Quimerismo , Neovascularização Fisiológica , Animais , DNA/genética , Feminino , Fígado/metabolismo , Masculino , Osteogênese , RNA/genética , RNA/metabolismo , Baço/metabolismo , Suínos , Transplante Homólogo
8.
Microsurgery ; 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32233045

RESUMO

PURPOSE: Adipose derived mesenchymal stem cells (MSCs) are hypothesized to supplement tissues with growth factors essential for regeneration and neovascularization. The purpose of this study was to determine the effect of MSCs with respect to neoangiogenesis when seeded onto a decellularized nerve allograft in a rat sciatic nerve defect model. METHODS: Allograft nerves were harvested from Sprague-Dawley rats and decellularized. MSCs were obtained from Lewis rats. 10 mm sciatic nerve defects in Lewis rats were reconstructed with reversed autograft nerves, decellularized allografts, decellularized allografts seeded with undifferentiated MSC or decellularized allografts seeded with differentiated MSCs. At 16 weeks, the vascular surface area and volume were evaluated. RESULTS: The vascular surface area in normal nerves (34.9 ± 5.7%), autografts (29.5 ± 8.7%), allografts seeded with differentiated (38.9 ± 7.0%) and undifferentiated MSCs (29.2 ± 3.4%) did not significantly differ from each other. Unseeded allografts (21.2 ± 6.2%) had a significantly lower vascular surface area percentage than normal nonoperated nerves (13.7%, p = .001) and allografts seeded with differentiated MSCs (17.8%, p = .001). Although the vascular surface area was significantly correlated to the vascular volume (r = .416; p = .008), no significant differences were found between groups concerning vascular volumes. The vascularization pattern in allografts seeded with MSCs consisted of an extensive nonaligned network of microvessels with a centripetal pattern, while the vessels in autografts and normal nerves were more longitudinally aligned with longitudinal inosculation patterns. CONCLUSIONS: Neoangiogenesis of decellularized allograft nerves was enhanced by stem cell seeding, in particular by differentiated MSCs. The pattern of vascularization was different between decellularized allograft nerves seeded with MSCs compared to autograft nerves.

9.
J Hand Surg Am ; 2020 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-32268979

RESUMO

PURPOSE: To characterize the dorsal ulnar corner fragment with regard to size and morphology using 3-dimensional software and computed tomography (CT) scans, as it presents in low-energy intra-articular distal radius fractures occurring in the female postmenopausal population. METHODS: A multicenter retrospective review was conducted to identify postmenopausal females with low-energy distal radius fractures treated surgically at level-1 trauma centers. Patients with low-energy injuries with preoperative CT scans were included. The Digital Imaging and Communications in Medicine (DICOM) data from CT scans were used to reconstruct intra-articular fracture patterns. The dorsal ulnar fragment was isolated in each CT scan and measured, then normalized based on lunate depth. RESULTS: Eighty patients met the inclusion criteria. The mean dimension measurements of the dorsal ulnar corner were dorsal surface height, 9.82 ± 5.02 mm (95% confidence interval [95% CI], 8.72-10.92); dorsal surface width, 9.06 ± 3.72 mm (95% CI, 8.25-9.88); articular surface width, 7.44 ± 3.92 mm (95% CI, 6.58-8.30); articular surface depth, 4.14 ± 2.39 mm (95% CI, 3.62-4.67). The mean lunate depth measurement (17.52 ± 1.48 mm) was used to normalize articular surface depth demonstrating that, on average, the dorsal ulnar corner comprises 23.6% of the articular surface ± 13.6% (95% CI, 20.7-26.6). CONCLUSIONS: The mean articular surface depth of the dorsal ulnar corner fragment in this study was less than 5 mm, accounting for approximately 24% of the volar-dorsal width of the distal radius at the lunate facet. CLINICAL RELEVANCE: These data expand current understanding of the morphology and size of the dorsal ulnar corner fracture fragment. If fixation of this fragment is a goal, surgeons may need to use longer screws that penetrate closer to the dorsal cortex than those required for extra-articular fractures or to consider alternative methods of fragment-specific fixation for adequate capture of this fragment.

10.
J Neuroeng Rehabil ; 17(1): 43, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32151268

RESUMO

The field of prosthetics has been evolving and advancing over the past decade, as patients with missing extremities are expecting to control their prostheses in as normal a way as possible. Scientists have attempted to satisfy this expectation by designing a connection between the nervous system of the patient and the prosthetic limb, creating the field of neuroprosthetics. In this paper, we broadly review the techniques used to bridge the patient's peripheral nervous system to a prosthetic limb. First, we describe the electrical methods including myoelectric systems, surgical innovations and the role of nerve electrodes. We then describe non-electrical methods used alone or in combination with electrical methods. Design concerns from an engineering point of view are explored, and novel improvements to obtain a more stable interface are described. Finally, a critique of the methods with respect to their long-term impacts is provided. In this review, nerve electrodes are found to be one of the most promising interfaces in the future for intuitive user control. Clinical trials with larger patient populations, and for longer periods of time for certain interfaces, will help to evaluate the clinical application of nerve electrodes.

11.
Artigo em Inglês | MEDLINE | ID: mdl-32187174

RESUMO

Management of hand and wrist avascular necrosis with osteochondral fragmentation or focal arthritis can be a challenging problem with a variety procedures described for its treatment. Osteochondral autograft transplantation systems have been utilized in various focal defects of the knee, ankle, elbow, and wrist. The same principle for the treatment of focal defects of the proximal scaphoid, proximal capitate as well as metacarpal head as an alternative treatment is described. The main indication for this treatment is to address focal or partial osteochondral defects where the size of the defect is smaller than the isthmus of the involved bone to accommodate a cylindrical osteochondral graft that can be press fit. Larger and complete defects are contraindications to this treatment. We discuss the surgical technique as well as its main indications and expected outcomes.

12.
Artigo em Inglês | MEDLINE | ID: mdl-32195826

RESUMO

Kienböck disease, osteonecrosis of the lunate, is a well-known but poorly understood complication seen by hand surgeons. This review presents the background and important patient-specific parameters of the disease and reviews the numerous treatment options that exist for the disease.

13.
Plast Reconstr Surg ; 145(4): 969-976, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32221216

RESUMO

BACKGROUND: This study assessed the risk and factors of complications after volar locking plate fixation of distal radius fractures. METHODS: A single-institution retrospective review of patients undergoing volar locking plate fixation of distal radius fractures between May of 2000 and May of 2015 was undertaken. Demographic data, major complications, minor complications, and radiographic parameters were evaluated. RESULTS: Six hundred forty-seven distal radius fractures managed with volar plate fixation in 636 patients were reviewed. Mean follow-up was 9.1 months. Mean age was 56.5 years. Mean body mass index was 28.0, and 14.6 percent of patients had a body mass index greater than 35. Fractures were classified as Arbeitsgemeinschaft für Osteosynthesefragen class 23-C (67.2 percent), 23-A (26.6 percent), and 23-B (6.2 percent). The incidence of major and minor complications was 13.8 percent and 17.5 percent, respectively. The most common complication was transient paresthesia (9.7 percent). The incidence of tendon rupture or irritation was 0.5 percent or 2.5 percent, respectively. Hardware removal for painful/symptomatic hardware occurred in 6.2 percent at an average of 427.8 days after surgery. Major complications and minor complications were increased 2.2- and 1.9-fold, respectively, in patients with a body mass index greater than 35. Major complications were also increased 3.19 times in patients with residual intraarticular step-off. Hardware removal was 3.3 times more likely in patients with Soong grade 2 plate prominence and 2.9 times more likely in patients with a history of diabetes mellitus. CONCLUSIONS: Volar plate osteosynthesis of distal radius fractures is associated with an overall low complication rate. Patient factors, including diabetes mellitus and obesity, and intraoperative factors, including intraarticular fracture alignment and plate prominence, were associated with a higher rate of complications or revision surgery. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

14.
Plast Reconstr Surg ; 145(6): 1442-1450, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32195864

RESUMO

BACKGROUND: Processed nerve allografts are a promising alternative to nerve autografts, providing an unlimited, readily available supply and avoiding donor-site morbidity and the need for immunosuppression. Currently, clinically available nerve allografts do not provide satisfactory results for motor reconstruction. This study evaluated motor recovery after reconstruction of a long nerve gap using a processed nerve allograft and the influence of storage techniques. METHODS: Nerve allografts were decellularized using elastase and detergents and stored at either 4° or -80°C. In 36 New Zealand White rabbits, a 3-cm peroneal nerve gap was repaired with either an autograft (group 1, control) or a cold-stored (group 2) or frozen-stored (group 3) processed nerve allograft. Nerve recovery was evaluated using longitudinal ultrasound measurements, electrophysiology (compound muscle action potentials), isometric tetanic force, wet muscle weight, and histomorphometry after 24 weeks. RESULTS: Longitudinal ultrasound measurements showed that the cold-stored allograft provided earlier regeneration than the frozen-stored allograft. Furthermore, ultrasound showed significantly inferior recovery in group 3 than in both other groups (p < 0.05). Muscle weight and isometric tetanic force showed similar outcomes in the autograft and cold-stored allograft groups [p = 0.096 (muscle weight) and p = 0.286 (isometric tetanic force)], and confirmed the inferiority of the frozen-stored allograft to the autograft [p < 0.01 (muscle weight) and p = 0.02 (isometric tetanic force)]. CONCLUSIONS: Frozen storage of the nerve allograft significantly impairs functional recovery and should be avoided. The cold-stored optimized nerve allograft yields functional recovery similar to the gold standard autograft in the reconstruction of a 3-cm motor nerve defect. Future studies should focus on further improvement of the nerve allograft.

15.
J Plast Reconstr Aesthet Surg ; 73(5): 959-964, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32059943

RESUMO

While surgical management of cubital tunnel syndrome (CuTS) results in the improvement of pain, paresthesia and restoration of motor function, there is a subset of patients who do not improve after primary surgery and require revision. The purpose of this study was to evaluate the incidence and risk factors for revision after primary CuTS. A retrospective review of patients who underwent revision CuTS after unsuccessful primary surgery from February 1989 to May 2009 was performed. Data regarding patients' demographics, age at primary and revision surgeries, handedness, presenting symptoms and the duration, physical examination, McGowan grading, electrodiagnostic findings and final outcomes were collected. A total of 1239 patients undergoing 1279 cubital tunnel surgeries were identified; of which 17 patients who underwent 18 revision CuTS met our inclusion criteria. Forty-one randomly selected consecutive patients who underwent primary CuTS (control cohort) were compared to identify the risk factors associated with revision CuTS. Younger age at presentation, greater static 2-point discrimination (S2PD) and a history of diabetes were associated with a greater number of revision surgeries. Patients requiring revision for primary CuTS were 8.4 years on average younger, had greater S2PD and were more likely to have diabetes. Pain as a presenting symptom compared to weakness and numbness was also a more common complaint in this cohort of patients. Future larger multicenter prospective studies are recommended.

16.
J Plast Reconstr Aesthet Surg ; 73(3): 460-468, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31928962

RESUMO

INTRODUCTION: The specific patterns of revascularization of allograft nerves after the addition of vascularization remain unknown. The aim of this study was to determine the revascularization patterns of optimized processed allografts (OPA) after surgically induced angiogenesis to the wound bed in a rat sciatic nerve model. MATERIALS AND METHODS: In 51 Lewis rats, sciatic nerve gaps were repaired with (i) autografts, (ii) OPA and (iii) OPA wrapped in a pedicled superficial inferior epigastric artery fascia flap (SIEF) to provide vascularization to the wound bed. At 2, 12, and 16 weeks, the vascular volume and vascular surface area in nerve samples were measured using micro CT and photography. Cross-sectional images were obtained and the number of vessels was quantified in the proximal, mid, and distal sections of the nerve samples. RESULTS: At 2 weeks, the vascular volume of SIEF nerves was comparable to control (P = 0.1). The vascular surface area in SIEF nerves was superior to other groups (P<0.05). At 12 weeks, vascularity in SIEF nerves was significantly higher than allografts (P<0.05) and superior compared to all other groups (P<0.0001) at 16 weeks. SIEF nerves had a significantly increased number of vessels compared to allografts alone in the proximal (P<0.05) and mid-section of the graft (P<0.05). CONCLUSIONS: Addition of surgical angiogenesis to the wound bed greatly improves revascularization. It was demonstrated that revascularization occurs primarily from proximal to distal (proximal inosculation) and not from both ends as previously believed and confirms the theory of centripetal revascularization.

17.
Plast Reconstr Surg ; 2020 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-31929453

RESUMO

BACKGROUND: To assess the risk and factors of complications after volar locking plate fixation of distal radius fractures (VLPDR). METHODS: A single institution retrospective review of patients undergoing VLPDR between May 2000-May 2015 was undertaken. Demographic data, major complications, minor complications and radiographic parameters were evaluated. RESULTS: 647 distal radius fractures managed with volar plate fixation in 636 patients were reviewed. Mean follow-up was 9.1 months. Mean age was 56.5 years. Mean BMI was 28.0 and 14.6% of patients had a BMI greater than 35. Fractures were classified as AO class 23-C(67.2%), 23-A(26.6%) and 23-B(6.2%). The incidence of major and minor complications was 13.8% and 17.5%, respectively. The most common complication was transient paresthesia(9.7%). The incidence of tendon rupture or irritation was 0.5% or 2.5%, respectively. Hardware removal for painful/symptomatic hardware occurred in 6.2% at an average of 427.8 days post-surgery. Major complications and minor complications were increased 2.2 and 1.9 fold in patients with a BMI>35. Major complications were also increased 3.19 times in patients with residual intra-articular step off. Hardware removal was 3.3 times more likely in patients with Soong Grade 2 plate prominence and 2.9 times more likely in patients with a history of diabetes. CONCLUSIONS: Volar plate osteosynthesis of distal radius fractures is associated with an overall low-complication rate. Patient factors including diabetes and obesity as well as intra-operative factors including intra-articular fracture alignment and plate prominence were associated with a higher rate of complications or revision surgery.

18.
Microsurgery ; 40(2): 183-188, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31246325

RESUMO

PURPOSE: Animal models can be helpful in evaluating new surgical strategies for brachial plexus reconstruction. While several groups have already used the rabbit brachial plexus to model injury, reports conflict in anatomic detail and do not identify a nerve-muscle pair to measure motor function recovery after reconstruction. The purpose of the current study is to describe the innervations of the biceps and triceps muscles in rabbits, which are both amenable to study in brachial plexus injury models. MATERIALS AND METHODS: Thirteen rabbits weighing 2-2.5 kg were anesthetized. Six rabbits were sacrificed and dissected using loupe and microscope magnification to understand the overall morphology of the brachial plexus. Seven rabbits underwent electrophysiologic investigation. A bipolar nerve stimulator was used to systematically stimulate the roots, trunks and divisions, and nerve branches of the rabbit brachial plexus and compound muscle action potential was used to record muscle response. Nerve length and width measurements were not recorded. RESULTS: Roots contributing to the brachial plexus were C5, C6, C7, C8, and T1. In contrast to other anatomical studies, T2 did not contribute to the brachial plexus. The triceps was innervated by the radial nerve, which received contributions from C6 (1.6 mA), C7 (1.9 mA), C8, and T1 (12.2 mA).The biceps had dual innervation (proximally and distally). The proximal branch received contributions from C6 (3.5 mA) and C7 (5mA). The distal portion was innervated by a branch from the median nerve, which received innervation from C6, C7, C8, and T1. CONCLUSIONS: The overall structure of rabbit brachial plexus is described and innervation of the biceps and triceps is described in detail. This anatomic investigation will form the basis of a future brachial plexus model of injury and repair.

19.
J Orthop Res ; 38(2): 288-296, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31579953

RESUMO

Vascularized composite allotransplantation of bone is a possible alternative treatment for large osseous defects but requires life-long immunosuppression. Surgical induction of autogenous neo-angiogenic circulation maintains transplant viability without this requirement, providing encouraging results in small animal models [1-3]. A preliminary feasibility study in a swine tibia model demonstrated similar findings [4, 5]. This study in swine tibial allotransplantation tests its applicability in a pre-clinical large animal model. Previously, we have demonstrated bone vascularized composite allotransplantation (VCA) survival was not the result of induction of tolerance nor an incompetent immune system [1]. Fourteen tibia vascularized bone allotransplants were microsurgically transplanted orthotopically to reconstruct size-matched tibial defects in Yucatan miniature swine. Two weeks of immunosuppression was used to maintain allotransplant pedicle patency during angiogenesis from a simultaneously implanted autogenous arteriovenous bundle. The implanted arteriovenous bundle was patent in group 1 and ligated in group 2 (a neo-angiogenesis control). At twenty weeks, we quantified the neo-angiogenesis and correlated it with transplant viability, bone remodeling, and gene expression. All patent arteriovenous bundles maintained patency throughout the survival period. Micro-angiographic, osteocyte cell count and bone remodeling parameters were significantly higher than controls due to the formation of a neo-angiogenic autogenous circulation. Analysis of gene expression found maintained osteoblastic and osteoclastic activity as well as a significant increase in expression of endothelial growth factor-like 6 (EGFL-6) in the patent arteriovenous bundle group. Vascularized composite allotransplants of swine tibia maintained viability and actively remodeled over 20 weeks when short-term immunosuppression is combined with simultaneous autogenous neo-angiogenesis. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:288-296, 2020.

20.
J Reconstr Microsurg ; 36(2): 82-92, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31470456

RESUMO

BACKGROUND: Bone vascularized composite allotransplantation (VCA) is a possible alternative for the treatment of large bone defects. Clinical application of VCAs is limited by the need for life-long immunosuppression (IS). We report an alternative method to maintain bone allotransplant viability in a large animal model without the need for life-long IS by using autogenous vessel implantation. METHODS: Fourteen bone only VCAs were transplanted in a porcine tibia defect model with short-term IS. Two groups were used to evaluate the effect of the implantation of an autogenous arteriovenous (AV)-bundle, therefore the only difference between the groups was the patency of the AV-bundle. We radiographically evaluated bone healing and allogenic pedicle patency. AV-bundle patency and union were evaluated with micro-CT. Bone remodeling was assessed with histomorphometry and material properties were evaluated with axial compression testing and cyclic reference point indentation. RESULTS: Two subjects did not reach the final time point. Twelve tibiae healed proximally, and nine at the distal transplant-bone interface. Bone allotransplants showed their viability in the first 4 to 6 weeks by significant periosteal bridging arising from the transplant and maintained pedicle patency. Bone material properties were not affected by the implantation of an AV-bundle when compared with ligated AV-bundle controls, but diminished compared with normal bone. Significantly higher bone formation rates resulted from the implantation of a patent AV-bundle. CONCLUSION: New periosteal bone formation and subsequent bone healing result from blood flow through the microsurgically repaired nutrient blood supply, demonstrated by maintained allogenic pedicle patency. The implantation of a patent autogenous AV-bundle has no adverse effect on material properties, but a positive effect on bone remodeling of endosteal surfaces despite thrombosis of the allogenic pedicle. Bone material properties change after transplantation compared with normal bone, although 20-weeks survival time is relatively short for the final evaluation of bone material properties.

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