Citations

Objective: Successful repair of segmental peripheral nerve defects remains a clinical challenge. The current clinical gold standard for such injuries is to use an autologous nerve graft, but this creates donor site morbidity with loss of sensation and potential scarring. Processed nerve allografts have been used to bridge segmental nerve gaps experimentally and clinically. However, in large nerve defects, functional outcomes are not comparable with autograft reconstruction yet; the longer the nerve gap, the poorer the outcome. Nerve architecture and the extracellular matrix (ECM) are preserved after processing; however, all cellular material including Schwann cells and axons are removed. The addition of supporting cells has been proposed to improve the decellularized allograft. Adipose-Derived Mesenchymal Stem Cells (AMSC) can potentially provide the necessary support for nerve regeneration due to local production of essential growth factors. While the mechanisms underlying the neurotrophic potential of AMSC remains unknown, it is postulated that the remaining ECM still has biological activity that influences the AMSC and their differentiation. Therefore, the purpose of this study was to quantitate the changes in gene expression profiles of the cells and quantify the actual produced growth factors after seeding the allograft with AMSC in vitro. Method: A total of 35 human nerve allografts were decellularized and seeded with human AMSC. At each time point (1, 3, 14, 21, and 28 days), total RNA was extracted, reverse transcribed into complementary DNA (cDNA), and quantitative reverse transcription–polymerase chain reaction (qRT-PCR) was performed in combination with gene specific assays for genes essential for nerve regeneration including nerve growth factor (NGF), Brain-derived neurotrophic factor (BDNF), pleiotrophin vascular endothelial growth factor (PTN VEGF), and growth associated protein 43 (GAP43).Additional genes were analyzed to map AMSC characteristics including proliferation, apoptosis, myelinization, and ECM molecules. Production of growth factors was evaluated and quantified using enzyme-linked immunosorbent assay (ELISA). All samples were analyzed in triplicates and data were compared with AMSC cultured in media only. Results: Semiquantitative RT-PCR analysis showed that the interaction of the processed allograft and AMSC enhanced the expression of the neurotrophic factors NGF, BDNF, and GAP43. The expression of the angiogenic molecules, vascular endothelial growth factor A (VEGF-A) was also increased and remained significantly elevated at 28 days post seeding. Analysis of ECM-related gene expression showed that laminin subunit beta-2 (LAMB2), collagen type I alpha 1 (COL1A1), collagen type III alpha 1 (COL3A1), fibulin 1 (FBLN1), were significantly elevated until 21 days post seeding while after 28 days, these levels were normalized. Angiogenic factor cluster of differentiation 31 (CD31) and neurotrophic factor PTN expression were down regulated in the seeded cells. Quantitative results of the ELISA analysis are pending. We anticipate differences in growth factor levels released by the seeded allograft compared with the control expression levels. Conclusion: This study demonstrates that the remaining ECM of the decellularized nerve allograft has a stimulating effect on AMSC. Upon the seeding, secretion of neurotrophic and angiogenic factors were triggered; the cells cultured on the allograft showed enhanced levels of neurotrophic genes. This is hypothesized to be a consequence of specific cell-ECM interactions within the allograft. The combination of patient’s own easily accessible, abundant supply of stem cells harvested from adipose tissue and the readily available processed nerve allograft is potentially a promising method for individualized peripheral nerve repair.

Objective: The treatment of segmental bone defects remains challenging as complications frequently occur with the currently available methods, including vascularized autograft, prosthetic replacement, bone transport, and cryopreserved bone allograft (CBA). Although the use of CBA is comparatively simple, it lacks donor site morbidity and provides immediate stability; however, the grafts remain largely necrotic, resulting in high failure rates due to nonunion, infection, and stress fractures. Revitalizing the CBA has the potential to solve these problems. Previous studies in small animal models have shown the use of surgical revascularization to induce neoangiogenesis and improve bone viability in the CBA. The purpose of this study is to investigate if surgical revascularization enhances bone circulation and bone remodeling in a tibial defect orthotopic reconstruction model, placing a cryopreserved allograft in a Yucatan mini pig. Methods: Cryopreserved tibial bone allografts were transplanted in swine leukocyte antigen (SLA)-type-mismatched Yucatan mini pigs after creating a 3.5-cm segmental bone defect in the tibia. The anterior tibial arteriovenous bundle (AV-bundle) was inserted into the intramedullary canal. Eight pigs received a patent AV-bundle (revascularized group), 8 pigs received a proximally ligated AV-bundle (control group), and the contralateral side was used as an untreated control. The graft was fixated with a locking compression plate to provide a weightbearing construction. After 20 weeks, the pigs were killed and the tibia was removed and analyzed. Neoangiogenesis was evaluated by quantifying vascular volumes using the microcomputed tomography. Bone remodeling was measured by quantitative histomorphometry and micro-computed tomography. Results: Seven AV-bundles in the revascularized group were patent and 1 bundle was thrombosed due to partial dislocation of the graft. Total vascular volume was higher in the revascularized allografts (127 mm 3 ) compared with both the control group (40 mm 3 , P = .003) and the contralateral side (29 mm 3 P = .000). All patent bundles showed neovascularization extending into the cortical bone. Revascularized allografts had increased bone remodeling in the inner cortical area of the graft compared with the non-revascularized grafts (bone formation rate: 381 ± 60 µm 3 /µm 3 /year vs 299 ± 143 µm 3 /µm 3 /year, P = .05). In both the revascularized group and the control group, the bone formation rate exceed the contralateral side: In the revascularized grafts, the bone formation was 305% of contralateral side, and in the non-revascularized grafts, the bone formation was 179% of the contralateral side. There was no statistical significant difference in outer cortical bone formation between the revascularized and the non-revascularized allografts. Conclusion: Surgical revascularization of porcine tibial CBAs by implantation of an AV-bundle creates an enhanced autogenous neoangiogenic circulation and accelerates active bone formation.

Background: The purpose of this study is to describe a novel technique using an interposition vein graft for thumb replantation in these severe avulsion injuries. Methods: From 2002 to 2012, 8 patients underwent interposition venous bridge grafting from the dorsal radial artery at the anatomic snuffbox to the ulnar digital artery of the thumb. All patients had a traumatic thumb amputation with a severe injury to the ulnar digital artery. The technique began with bony stabilization; the radial artery at the anatomic snuffbox is exposed, vein graft harvested, and microsurgical end-to-side (proximally) and end-to-end (distally) anastomoses are carried out. Results: The average time to the operating room was 7.4 hours and time to reperfusion was 9.5 hours. At 3.1 years of follow-up, all 8 thumbs remained viable, without any need for revision procedures. The only complication was a metacarpal shaft nonunion treated successfully with iliac crest bone grafting. At last follow-up, all patients reported no or mild pain, with an average metacarpophalangeal (MCP) range of motion of 46.5°, and intact but diminished 2-point discrimination. All patients were able to return to work full-time. Conclusions: Due to the challenging nature of thumb avulsion injuries and the pronated position of the thumb, novel salvage alternatives are important. We describe a technique when no proximal vessels are available, using a vein to bridge the dorsal radial artery to the ulnar digital artery of the thumb. This novel arterial reconstruction has shown promise in thumb replantation associated with severe avulsion injuries.

This study describes a novel technique for the preoperative surgical planning for an osteoarticular medial femoral condyle (MFC) graft to replace the proximal pole of a scaphoid. In cases of proximal pole scaphoid nonunion or in Preiser disease, fragmentation of the articular surface can occur, leading to significant pain and disability. Osteoarticular MFC bone grafting can be used to treat these injuries by providing a vascularized osteoarticular surface. Using 3-dimensional imaging and printing we are able to precisely model the injured scaphoid, and also accurately plan the harvest of MFC osteoarticular graft. This technique allows for accurate preoperative planning of a complex 3-dimensional bone, and has improved our execution of the plan intraoperatively.

PurposeOur objective was to determine the prevalence and quality of restored external rotation (ER) in adult brachial plexus injury (BPI) patients who underwent spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer, and to identify patient and injury factors that may influence results.MethodsFifty‐one adult traumatic BPI patients who underwent SAN to SSN transfer between 2000 and 2013, all treated less than 1 year after injury with >1 year follow‐up. The primary outcome measured was shoulder ER. The outcomes we utilized included “clinically useful ER” (motion ≥ −35° with ≥MRC 2 strength), modified British Medical Research Council (MRC) grading, and electromyographic (EMG) reinnervation.ResultsEMG evidence of re‐innervation was found in 85% of patients. Surgery resulted in improved ER in 41% (21/51) of shoulders at an average of 28 months follow‐up. Of these, only 31% (17/51) had clinically useful ER. The average ER active range of motion was 12° from full internal rotation (Range: −60° to 90°) and MRC grade 2.2 (2–4). The only predictor of ER improvement was an isolated upper trunk (C5‐C6) injury. Improved ER was clinically evident in 76%, 37% and 26% of upper trunk (UT), C5‐C6‐C7 and panplexus injuries, respectively (P < 0.03).ConclusionsAlthough 85% had EMG signs of recovery, the SAN to SSN transfer failed to provide useful recovery of ER through reinnervation of the infraspinatus muscle in injuries involving more levels than a C5‐C6 root/upper trunk pattern. In patients with greater than C5‐6 level injuries alternatives to SAN to SSN transfer should be considered to restore shoulder ER. © 2016 Wiley Periodicals, Inc. Microsurgery 37:365–370, 2017.

Background: The objective of this study was to review the outcomes of patients who underwent one-bone forearm (OBF) reconstruction. Methods: A retrospective review of patients who underwent OBF surgery between 1994 and 2014 was undertaken. Patient demographics, etiology, associated injuries, number of surgeries prior to OBF surgery, surgical details, and postoperative information were collected. A telephone interview was conducted at final follow-up, including a Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire, a 10-point scoring system used by Peterson et al, and a series of questions concerning pain and patient satisfaction. Results: There were 6 males and 2 females with a mean age of 44 years (range, 20-66 years). All patients had traumatic etiology, with 6 having open wounds and 2 having closed wounds. All patients had union with a mean follow-up of 83.6 months (range, 16-218 months). The mean pain score was 3 (range, 0-8), of which 3 were painless (score 0). The mean QuickDASH score was 39 (range, 7-75), and 4 patients had good or excellent results according to the 10-point score system used by Peterson et al. All patients were satisfied with the result. Five of 8 had complications related to soft tissues that were residual from their prior injuries and surgeries. One patient had post healing fracture requiring revision fixation and 1 had a postoperative infection requiring parenteral antibiotics. Conclusions: OBF surgery is an effective salvage procedure for complicated forearm instability, particularly after trauma. While union rates are high, complications are typically related to pain and soft tissue secondary to the previous injury and reconstructive procedures.

Background: The purpose of this study is to evaluate long-term outcomes of ligamentous repair rather than reconstruction for chronic thumb ulnar collateral ligament (UCL) injuries. Methods: Patients at least 15-years status-post repair of a chronic (greater than 6 weeks) UCL tear were contacted for clinical evaluation, radiographs, and postoperative outcome questionnaires, including the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, visual analog scale (VAS) pain scale, and study-specific questions. Twelve of 21 (57%) living patients were available for long-term, greater than 15-year follow-up (average 24.5 years, range 16.9-35.6). Results: Eighty-eight percent of patients had some degree of osteoarthritis. Increased age at the time of injury and higher DASH scores were correlated with increased grades of the thumb metacarpophalangeal osteoarthritis. Delay to treatment and VAS pain scores had no correlation with radiographic findings. Conclusions: Repair of a chronic UCL injury with available local tissue appears to be a reasonable alternative to ligament reconstruction, resulting in durable long-term outcomes despite the majority of patients progressing to osteoarthritis.

Most distal radius fractures are the result of low-energy mechanisms that can be successfully treated either non-operatively or with a variety of operative techniques if indicated. Complex distal radius fractures occur most commonly in high-energy injuries with extensive comminution or bone loss and associated soft tissue or vascular injuries. These high-energy fractures can present many challenges in reconstructing the distal radius. Effective restoration of the bony architecture requires a thorough knowledge of distal radius anatomy, understanding of the goals of treatment, versatility in surgical approaches, and familiarity with multiple fixation options.