Aorto-bronchial and aorto-pulmonary fistulation after thoracic endovascular aortic repair: an analysis from the European Registry of Endovascular Aortic Repair Complications

OBJECTIVES To learn upon incidence, underlying mechanisms and effectiveness of treatment strategies in patients with central airway and pulmonary parenchymal aorto-bronchial fistulation after thoracic endovascular aortic repair (TEVAR). METHODS Analysis of an international multicentre registry (European Registry of Endovascular Aortic Repair Complications) between 2001 and 2012 with a total caseload of 4680 TEVAR procedures (14 centres). RESULTS Twenty-six patients with a median age of 70 years (interquartile range: 60-77) (35% female) were identified. The incidence of either central airway (aorto-bronchial) or pulmonary parenchymal (aorto-pulmonary) fistulation (ABPF) in the entire cohort after TEVAR in the study period was 0.56% (central airway 58%, peripheral parenchymal 42%). Atherosclerotic aneurysm formation was the leading indication for TEVAR in 15 patients (58%). The incidence of primary endoleaks after initial TEVAR was n = 10 (38%), of these 80% were either type I or type III endoleaks. Fourteen patients (54%) developed central left bronchial tree lesions, 11 patients (42%) pulmonary parenchymal lesions and 1 patient (4%) developed a tracheal lesion. The recognized mechanism of ABPF was external compression of the bronchial tree in 13 patients (50%), the majority being due to endoleak formation, further ischaemia due to extensive coverage of bronchial feeding arteries in 3 patients (12%). Inflammation and graft erosion accounted for 4 patients (30%) each. Cumulative survival during the entire study period was 39%. Among deaths, 71% were attributed to ABPF. There was no difference in survival in patients having either central airway or pulmonary parenchymal ABPF (33 vs 45%, log-rank P = 0.55). Survival with a radical surgical approach was significantly better when compared with any other treatment strategy in terms of overall survival (63 vs 32% and 63 vs 21% at 1 and 2 years, respectively), as well as in terms of fistula-related survival (63 vs 43% and 63 vs 43% at 1 and 2 years, respectively). CONCLUSIONS ABPF is a rare but highly lethal complication after TEVAR. The leading mechanism behind ABPF seems to be a continuing external compression of either the bronchial tree or left upper lobe parenchyma. In this setting, persisting or newly developing endoleak formation seems to play a crucial role. Prognosis does not differ in patients with central airway or pulmonary parenchymal fistulation. Radical bronchial or pulmonary parenchymal repair in combination with stent graft removal and aortic reconstruction seems to be the most durable treatment strategy.

An educational review of cartilage repair: precepts & practice - myths & misconceptions - progress & prospects.

OBJECTIVE The repair of cartilaginous lesions within synovial joints is still an unresolved and weighty clinical problem. Although research activity in this area has been indefatigably sustained, no significant progress has been made during the past decade. The aim of this educational review is to heighten the awareness amongst students and scientists of the basic issues that must be tackled and resolved before we can hope to escape from the whirlpool of stagnation into which we have fallen: cartilage repair redivivus! DESIGN Articular-cartilage lesions may be induced traumatically (e.g., by sports injuries and occupational accidents) or pathologically during the course of a degenerative disease (e.g., osteoarthritis). This review addresses the biological basis of cartilage repair and surveys current trends in treatment strategies, focussing on those that are most widely adopted by orthopaedic surgeons [viz., abrasive chondroplasty, microfracturing/microdrilling, osteochondral grafting and autologous-chondrocyte implantation (ACI)]. Also described are current research activities in the field of cartilage-tissue engineering, which, as a therapeutic principle, holds more promise for success than any other experimental approach. RESULTS AND CONCLUSIONS Tissue engineering aims to reconstitute a tissue both structurally and functionally. This process can be conducted entirely in vitro, initially in vitro and then in vivo (in situ), or entirely in vivo. Three key constituents usually form the building blocks of such an approach: a matrix scaffold, cells, and signalling molecules. Of the proposed approaches, none have yet advanced beyond the phase of experimental development to the level of clinical induction. The hurdles that need to be surmounted for ultimate success are discussed.

Retinal layer measurements after successful macula-off retinal detachment repair using optical coherence tomography

PURPOSE Optical coherence tomography (OCT) was used to analyze the thickness of various retinal layers of patients following successful macula-off retinal detachment (RD) repair. METHODS Optical coherence tomography scans of patients after successful macula-off RD repair were reanalyzed with a subsegmentation algorithm to measure various retinal layers. Regression analysis was performed to correlate time after surgery with changes in layer thickness. In addition, patients were divided in two groups. Group 1 had a follow-up period after surgery of up to 7 weeks (range, 21-49 days). In group 2, the follow-up period was >8 weeks (range, 60-438 days). Findings were compared to a group of age-matched healthy controls. RESULTS Correlation analysis showed a significant positive correlation between inner nuclear-outer plexiform layer (INL-OPL) thickness and time after surgery (P=0.0212; r2=0.1551). Similar results were found for the ellipsoid zone-retinal pigment epithelium complex (EZ-RPE) thickness (P=0.005; r2=0.2215). Ganglion cell-inner plexiform layer thickness (GCL-IPL) was negatively correlated with time after surgery (P=0.0064; r2=0.2101). For group comparison, the retinal nerve fiber layer in both groups was thicker compared to controls. The GCL-IPL showed significant thinning in group 2. The outer nuclear layer was significantly thinner in groups 1 and 2 compared to controls. The EZ-RPE complex was significantly thinner in groups 1 and 2 compared to controls. In addition, values in group 1 were significantly thinner than in group 2. CONCLUSIONS Optical coherence tomography retinal layer thickness measurements after successful macular-off RD repair revealed time-dependent thickness changes. Inner nuclear-outer plexiform layer thickness and EZ-RPE thickness was positively correlated with time after surgery. Ganglion cell-inner plexiform layer thickness was negatively correlated with time after surgery.

Dynamic intraligamentary stabilization and primary repair: A new concept for the treatment of knee dislocation.

BACKGROUND Traumatic knee dislocation represents a rare but devastating injury. Several controversies persist regarding type of treatment, surgical timing, graft selection, repair versus reconstruction of the medial and lateral structures, surgical techniques and postoperative rehabilitation. A new technique for primary ACL stabilization, dynamic intaligamentary stabilization (DIS) was developed at the authors' institution. The purpose of this study was to analyze the clinical and radiological outcomes of surgically treated traumatic knee dislocations by means of the DIS technique for the ACL, primary suturing for PCL, MCL and LCL. METHODS Between 2009 and 2012, 35 patients treated surgically for traumatic knee dislocation with primary anterior cruciate ligament (ACL) reconstruction with DIS, suturing of the posterior cruciate ligament (PCL) and primary complete repair of collaterals, were evaluated clinically (IKDC score, SF12 health survey, Lysholm score, Tegner score) and radiologically with a mean follow up of 2.2 years (range 1.00-3.50 years) years. Instrumented anterior-posterior translation was measured (KT-2000). RESULTS Anterior/posterior translation (KT-2000) for the healthy and injured limb was 4.8mm (range 3-8mm) and 7.3mm (range 5-10) (89N) respectively. Valgus and varus stress testing in 30° flexion was normal in 26 (75%) and 29 (83%) patients, respectively. The IKDC score was B in 29 (83%) and C in 6 (17%) patients, while the mean Tegner score was 6 (range 4-8). The mean Lysholm score was 90.83 (range 81-95) and mean SF-12 physical and mental scores were 54.1 (range 45-60) and 51.0 (range 39-62) respectively. In 2 patients, a secondary operation was performed. CONCLUSIONS Early, one stage reconstruction with DIS can achieve good functional results and patient satisfaction with overall restoration of sports and working capacity without graft requirements.

Renal microvascular assembly and repair: power and promise of molecular definition.

Developmental assembly of the renal microcirculation is a precise and coordinated process now accessible to experimental scrutiny. Although definition of the cellular and molecular determinants is incomplete, recent findings have reframed concepts and questions about the origins of vascular cells in the glomerulus and the molecules that direct cell recruitment, specialization and morphogenesis. New findings illustrate principles that may be applied to defining critical steps in microvascular repair following glomerular injury. Developmental assembly of endothelial, mesangial and epithelial cells into glomerular capillaries requires that a coordinated, temporally defined series of steps occur in an anatomically ordered sequence. Recent evidence shows that both vasculogenic and angiogenic processes participate. Local signals direct cell migration, proliferation, differentiation, cell-cell recognition, formation of intercellular connections, and morphogenesis. Growth factor receptor tyrosine kinases on vascular cells are important mediators of many of these events. Cultured cell systems have suggested that basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF) promote endothelial cell proliferation, migration or morphogenesis, while genetic deletion experiments have defined an important role for PDGF beta receptors and platelet-derived growth factor (PDGF) B in glomerular development. Receptor tyrosine kinases that convey non-proliferative signals also contribute in kidney and other sites. The EphB1 receptor, one of a diverse class of Eph receptors implicated in neural cell targeting, directs renal endothelial migration, cell-cell recognition and assembly, and is expressed with its ligand in developing glomeruli. Endothelial TIE2 receptors bind angiopoietins (1 and 2), the products of adjacent supportive cells, to signals direct capillary maturation in a sequence that defines cooperative roles for cells of different lineages. Ultimately, definition of the cellular steps and molecular sequence that direct microvascular cell assembly promises to identify therapeutic targets for repair and adaptive remodeling of injured glomeruli.

Only Neochordoplasty Achieves Physiological Trans-valvular Pressure Gradients After Repair Of Acute Posterior Leaflet Prolapse In Porcine Mitral Valves

Objective: Minimizing resection and preserving leaflet tissue has been previously shown to be beneficial for mitral valve function and leaflet kinematics after repair of acute posterior leaflet prolapse in porcine valves. We examined the effects of different additional methods of mitral valve repair (neochordoplasty, ring annuloplasty, edge-to-edge repair and triangular resection) on hemodynamics at different heart rates in an experimental model. Methods: Severe acute P2 prolapse was created in eight porcine mitral valves by resecting the posterior marginal chordae. Valve hemodynamics was quantified under pulsatile conditions in an in vitro heart simulator before and after surgical manipulation. Mitral regurgitation was corrected using four different methods of repair on the same valve: neochordoplasty with expanded polytetrafluoroethylene sutures alone and together with ring annuloplasty, edge-to-edge repair and triangular resection, both with non-restrictive annuloplasty. Residual mitral valve leak, trans-valvular pressure gradients, flow and cardiac output were measured at 60 and 80 beats/min. A validated statistical linear mixed model was used to analyze the effect of treatment. The p values were calculated using a two-sided Wald test. Results: Only neochordoplasty with expanded polytetrafluoroethylene sutures but without ring annuloplasty achieved similar hemodynamics compared to those of the native mitral valve (p range 0.071-0.901). Trans-valvular diastolic pressure gradients were within a physiologic range but significantly higher than those of the native valve following neochordoplasty with ring annuloplasty (p=0.000), triangular resection (p=0.000) and edge-to-edge repair (p=0.000). Neochordoplasty alone was significantly better in terms of hemodynamic than neochordoplasty with a ring annuloplasty (p=0.000). These values were stable regardless of heart rate or ring size. Conclusions: Neochordoplasty without ring annuloplasty is the only repair technique able to achieve almost native physiological hemodynamics after correction of leaflet prolapse in a porcine experimental model of acute chordal rupture.

Nerve Transfers for Persistent Traumatic Peroneal Nerve Palsy: The Inselspital Bern Experience

BACKGROUND Patients in whom conventional peroneal nerve repair surgery failed to reconstitute useful foot lift need to be evaluated for their suitability to undergo a concomitant tendon transfer procedure or nerve transfers. OBJECTIVE To report our first clinical experience with nerve transfers for persistent traumatic peroneal nerve palsy. METHODS Between 2007 and 2013, 8 patients were operated on for foot drop after unsuccessful nerve surgery. Six patients without fatty degeneration of the anterior tibial muscle and proximal lesion of the peroneal nerve were oriented for tibial to peroneal nerve transfer. In the other 2 cases where the anterior and lateral compartments were destructed, the anterior tibial muscle function was reconstructed with a neurotized lateral gastrocnemius transfer. For each patient, we graded postoperative results using the Bureau of Meteorology Research Centre scheme and the Ninkovic assessment scale. RESULTS Of the 6 patients who underwent nerve transfer of the anterior tibial muscle, 2 patients had excellent results, 1 patient had good results, 1 patient had fair results, and 2 patients had poor results. Of the 2 patients that underwent neurotized lateral gastrocnemius transfer, 1 patient achieved excellent results after tenolysis, whereas 1 patient achieved poor results. After the nerve transfer, 5 patients did not wear an ankle-foot orthosis. Four patients did not limp. Four patients were able to walk barefoot, navigate stairs, and participate in activities. CONCLUSION Early clinical results after tibial to peroneal nerve transfer and neurotized lateral gastrocnemius transfer appear mixed. The results of nerve transfer seem, on the whole, less reliable than the literature reports on tendon transfer. ABBREVIATIONS EMG, electromyographyNAP, nerve action potential.

Mechanical restoration and failure analyses of a hydrogel and scaffold composite strategy for annulus fibrosus repair

Unrepaired defects in the annulus fibrosus of intervertebral disks are associated with degeneration and persistent back pain. A clinical need exists for a disk repair strategy that can seal annular defects, be easily delivered during surgical procedures, and restore biomechanics with low risk of herniation. Multiple annulus repair strategies were developed using poly(trimethylene carbonate) scaffolds optimized for cell delivery, polyurethane membranes designed to prevent herniation, and fibrin-genipin adhesive tuned to annulus fibrosus shear properties. This three-part study evaluated repair strategies for biomechanical restoration, herniation risk and failure mode in torsion, bending and compression at physiological and hyper-physiological loads using a bovine injury model. Fibrin-genipin hydrogel restored some torsional stiffness, bending ROM and disk height loss, with negligible herniation risk and failure was observed histologically at the fibrin-genipin mid-substance following rigorous loading. Scaffold-based repairs partially restored biomechanics, but had high herniation risk even when stabilized with sutured membranes and failure was observed histologically at the interface between scaffold and fibrin-genipin adhesive. Fibrin-genipin was the simplest annulus fibrosus repair solution evaluated that involved an easily deliverable adhesive that filled irregularly-shaped annular defects and partially restored disk biomechanics with low herniation risk, suggesting further evaluation for disk repair may be warranted. Statement of significance Lower back pain is the leading cause of global disability and commonly caused by defects and failure of intervertebral disk tissues resulting in herniation and compression of adjacent nerves. Annulus fibrosus repair materials and techniques have not been successful due to the challenging mechanical and chemical microenvironment and the needs to restore biomechanical behaviors and promote healing with negligible herniation risk while being delivered during surgical procedures. This work addressed this challenging biomaterial and clinical problem using novel materials including an adhesive hydrogel, a scaffold capable of cell delivery, and a membrane to prevent herniation. Composite repair strategies were evaluated and optimized in quantitative three-part study that rigorously evaluated disk repair and provided a framework for evaluating alternate repair techniques.

Contemporary spinal cord protection during thoracic and thoracoabdominal aortic surgery and endovascular aortic repair: a position paper of the vascular domain of the European Association for Cardio-Thoracic Surgery†.

Ischaemic spinal cord injury (SCI) remains the Achilles heel of open and endovascular descending thoracic and thoracoabdominal repair. Neurological outcomes have improved coincidentially with the introduction of neuroprotective measures. However, SCI (paraplegia and paraparesis) remains the most devastating complication. The aim of this position paper is to provide physicians with broad information regarding spinal cord blood supply, to share strategies for shortening intraprocedural spinal cord ischaemia and to increase spinal cord tolerance to transitory ischaemia through detection of ischaemia and augmentation of spinal cord blood perfusion. This study is meant to support physicians caring for patients in need of any kind of thoracic or thoracoabdominal aortic repair in decision-making algorithms in order to understand, prevent or reverse ischaemic SCI. Information has been extracted from focused publications available in the PubMed database, which are cohort studies, experimental research reports, case reports, reviews, short series and meta-analyses. Individual chapters of this position paper were assigned and after delivery harmonized by Christian D. Etz, Ernst Weigang and Martin Czerny. Consequently, further writing assignments were distributed within the group and delivered in August 2014. The final version was submitted to the EJCTS for review in September 2014.

Novel MesoPorous BioGlass/silk scaffold containing adPDGF-B and adBMP7 for the repair of periodontal defects in beagle dogs

AIM The local delivery of growth factors via gene therapy has gained tremendous awareness in recent years due to their sustained growth factor delivery to target tissues. The aim of this study was to fabricate and investigate a scaffold able to release growth factors via gene therapy for the repair of periodontal tissues. MATERIALS AND METHODS Novel mesoporous bioglass (MBG)/silk fibrin scaffold combined with BMP7 and/or PDGF-B adenovirus was fabricated and tested in vitro for cell migration, proliferation and differentiation. Furthermore, acute-type buccal dehiscence periodontal defects (mesiodistal width × depth: 5 × 5 mm) were created on the buccal portion of the maxillary premolars in five normal male beagle dogs (12 months old, 15.0 ± 2.0 kg) and histologically examined for periodontal regeneration following implantation of the following five groups: (1) no scaffold, (2) MBG/silk scaffold alone, (3) scaffold + adPDGF-B, (4) scaffold + adBMP7, (5) scaffold + adPDGF-b + adBMP7. RESULTS In vitro findings demonstrated that adPDGF-B was able to rapidly recruit periodontal ligament (PDL) cells over sixfold more effectively than adBMP7, whereas adBMP7 was more able to induce osteoblast differentiation of PDL cells. In vivo findings demonstrate that scaffolds loaded with adPDGF-B were able to partially regenerate the periodontal ligament while adBMP7 scaffolds primarily improved new bone formation. The combination of both adPDGF-B and adBMP7 synergistically promoted periodontal regeneration by allowing up to two times greater regeneration of the periodontal ligament, alveolar bone and cementum when compared to each adenovirus used alone. CONCLUSIONS Although both PDGF-B and BMP7 are individually capable of promoting periodontal regeneration to some degree, their combination synergistically promotes wound healing in acute-type buccal dehiscence periodontal defects when delivered simultaneously. This study demonstrates the promise for successful delivery of low-cost, effective growth factor delivery via gene therapy for the treatment of periodontal defects.