Treatment and outcome of fracture-related infection of the clavicle.

INTRODUCTION: The number of operatively treated clavicle fractures has increased over the past decades. Consequently, this has led to an increase in secondary procedures required to treat complications such as fracture-related infection (FRI). The primary objective of this study was to assess the clinical and functional outcome of patients treated for FRI of the clavicle. The secondary objectives were to evaluate the healthcare costs and propose a standardized protocol for the surgical management of this complication. METHODS: All patients with a clavicle fracture who underwent open reduction and internal fixation (ORIF) between 1 January 2015 and 1 March 2022 were retrospectively evaluated. This study included patients with an FRI who were diagnosed and treated according to the recommendations of a multidisciplinary team at the University Hospitals Leuven, Belgium. RESULTS: We evaluated 626 patients with 630 clavicle fractures who underwent ORIF. In total, 28 patients were diagnosed with an FRI. Of these, eight (29%) underwent definitive implant removal, five (18%) underwent debridement, antimicrobial treatment and implant retention, and fourteen patients (50%) had their implant exchanged in either a single-stage procedure, a two-stage procedure or after multiple revisions. One patient (3.6%) underwent resection of the clavicle. Twelve patients (43%) underwent autologous bone grafting (tricortical iliac crest bone graft (n = 6), free vascularized fibular graft (n = 5), cancellous bone graft (n = 1)) to reconstruct the bone defect. The median follow-up was 32.3 (P25-P75: 23.9-51.1) months. Two patients (7.1%) experienced a recurrence of infection. The functional outcome was satisfactory, with 26 out of 28 patients (93%) having full range of motion. The median healthcare cost was € 11.506 (P25-P75: € 7.953-23.798) per patient. CONCLUSION: FRI is a serious complication that can occur after the surgical treatment of clavicle fractures. In our opinion, when treated adequately using a multidisciplinary patient-specific approach, the outcome of patients with an FRI of the clavicle is good. The median healthcare costs of these patients are up to 3.5 times higher compared to non-infected operatively treated clavicle fractures. Although not studied individually, we consider factors such as the size of the bone defect, condition of the soft tissue, and patient demand important when it comes to guiding our surgical decision making in cases of osseous defects.

Fracture-related infection of the patella: Treatment options and outcome.

BACKGROUND: Fracture-related infection (FRI) after the operative management of patella fractures is a serious complication that can result in prolonged hospitalization, multiple revision procedures and permanent functional impairment. Till today, treatment modalities and outcome of FRI of the patella are not well described. Therefore, the main objective of this retrospective cohort study was to evaluate treatment options, functional outcome and healthcare costs related to FRI of the patella. METHODS: This study evaluated 111 consecutive patients that were surgically treated for patella fractures, at the department of trauma surgery of the University Hospitals Leuven (Belgium), between January 2015 and April 2020. Patients were excluded if they (1) were younger than 18 years at the time of injury or (2) died during follow up. The minimal follow-up for all patients was 18 months. RESULTS: During the 5-year study period, 107 patients with 108 patella fractures were included. A total of 10 patients were diagnosed with an FRI (9.3%). Four of these were treated with a DAIR approach and three patients underwent implant removal or exchange. Finally, three patients were treated with total patellectomy. Out of the 10 patients, two were diagnosed with a recurrence of infection. Overall, we observed substantial lower scores for all Knee Injury and Osteoarthritis Outcome Score subscales in the FRI group, compared to a reference population. Moreover, our study shows that direct hospital-related healthcare costs of FRI of the patella were nine times higher compared to non-FRI cases. CONCLUSIONS: FRI of the patella is a challenging complication and recurrence of infection not uncommon. Although multiple treatment modalities exist, a multidisciplinary patient-specific approach is crucial. An early or delayed onset infection can be managed with a DAIR approach, but only when the construct is stable and the soft tissue coverage adequate. In patients with an FRI, implant removal is preferred when the fracture has healed. A total patellectomy can be used as a salvage procedure in complex cases with acceptable functional results. Overall, FRI of the patella leads to both a negative impact on the functional status of the patient and a ninefold increase in total healthcare costs.

The Iliac Crest Osteomuscular Flap for Bony Reconstruction: Beast or Beauty? A Reassessment of the Value and Donor Site Morbidity in the CAD/CAM Era.

BACKGROUND: The iliac crest bone flap (ICBF), based on the deep circumflex iliac artery, has a bad reputation regarding donor site morbidity. However, the ICBF has an ideal curvature and shape for occlusion-based hemimandibular reconstructions with rapid dental rehabilitation and for vertical class III maxillary reconstructions that require bony support and muscular bulk to fill cavities and to provide intraoral lining. Is this notorious donor site reputation still valid with modern flap procurement using computer aided design/computer aided manufacturing (CAD/CAM) and recipient-site closure techniques? METHODS: We performed a literature search of the public databases PubMed, Cochrane, Google Scholar, and Web of Science for papers using mesh keywords related to donor site morbidity of the ICBF. We report three illustrative case reports using our current protocols for oncologic bony resection and reconstruction, using in-house CAD/CAM and three-dimensional printing to procure a tight-fit ICBF and minimizing donor site morbidity. RESULTS: We found 191 articles in the PubMed database of which we considered 176 nonrelevant. Cochrane Library and Google Scholar database searches resulted in the inclusion of 11 additional papers. The second search resulted in 172 articles of which we used five after excluding nonrelevant papers. Accurate preoperative (CAD/CAM) planning, preservation of the anterior superior iliac spine (ASIS), and paying attention to thoroughly donor site closure make the ICBF a very valuable option for accurate maxillofacial reconstructions with very acceptable comorbidities. This corresponds with our clinical findings. CONCLUSION: Dogma never is a good teacher; it remains elementary that routine "knowledge" is (re)questioned. Donor site morbidity of the ICBF is comparable to other bone flaps. The shape and bone stock of the ICBF is ideal and often may be first choice. In combination with CAD/CAM planning, the ICBF is an excellent option for specific maxillofacial reconstructions.

Treatment of basal cell carcinoma with vismodegib: future or present?

BACKGROUND: Since the introduction of Vismodegib as treatment of recurrent locally advanced basal cell carcinoma (laBCC), clinicians are faced with new dilemmas: 'Can Vismodegib replace complex reconstructions?', 'What is the role of neoadjuvant use of Vismodegib?' and 'What is the best approach in case of complete clinical remission after Vismodegib in a neoadjuvant setting?' METHODS: Case report and literature review. RESULTS: Case report Complete dermoscopic remission after eight months Vismodegib was obtained in a patient with recurrent laBCC. Follow-up was 12 months. Literature review: Vismodegib shows histologic clearance in 42% of patients with operable basal cell carcinoma. Recurrence after neoadjuvant use of Vismodegib in laBCC was described. Moreover, histology revealed residual tumour cells in cases of complete clinical remission after 6 months Vismodegib. CONCLUSIONS: Vismodegib cannot replace complex reconstructions. However, in unresectable laBCC, Vismodegib can provide a bridge to surgery. Due to the possibility of persistent tumour cells, we recommend imaging-assisted surgery and an imaging-based follow-up. In case of complete clinical remission after Vismodegib in a neoadjuvant setting, we recommend that Vismodegib be continued as long as the adverse effects are tolerated and an imaging-based follow-up is advised.

Requirements for Successful Trachea Transplantation: A Study in the Rabbit Model.

BACKGROUND: Although creating a tracheal tube de novo might appear straightforward, the first clinical applications have shown that reconstruction of long-segment tracheal defects remains challenging. In this study, the authors aimed to refine the baseline requirements of successful trachea transplantation by means of three proof-of-concept models in the rabbit. METHODS: In each model, one characteristic of a perfect tracheal transplant was eliminated. The first model was developed to map out the immunologic response of vascularized allogenic trachea, transplanted without immunosuppression (n = 6). The second model studied (1) the need for wrapping the transplant with a highly vascularized flap and (2) the source of angiogenesis after autologous trachea transplantation (n = 18). In the third model, the authors examined the importance of an inner epithelial covering (n = 12). All models were compared to a control group of heterotopically transplanted vascularized autologous tracheae (n = 6). RESULTS: Embedded in an avascular matrix, allogenic chondrocytes were protected from an overt immune response. Orthotopic transplantation without additional external vascular wrap was successful in a well-vascularized environment. Nonetheless, an external vascular source was essential to maintain viability of the construct. Epithelial covering was necessary to prevent secondary healing. Epithelial migration from the anastomoses or graft was not sufficient to cover long-segment defects. CONCLUSIONS: These experiments provided ample evidence of the importance of baseline requirements when designing a tracheal transplant study. This study confirmed that different tracheal cell types possess different immunologic sensitivities. External revascularization, preferably in a two-stage procedure, and fast reepithelialization were both paramount to successful transplantation.

Epithelial grafting of a decellularized whole-tracheal segment: an in vivo experimental model.

OBJECTIVES: Prerequisites for successful trachea transplantation include the use of a biocompatible construct, submucosal vascularization and an epithelial covering. Implantation of non-epithelialized tracheal scaffolds may lead to stenosis. However, epithelial grafting or seeding can only be attempted onto a well-vascularized submucosal bed. Our aim was to investigate a method to prevent stenosis during prelamination of non-epithelialized, gently decellularized rabbit tracheae and to evaluate whether grafting of revascularized constructs with buccal mucosa is feasible. METHODS: Allotracheae underwent two 48-h cycles of detergent-enzymatic decellularization using sodium deoxycholate and DNAse. In the first series, 12 circular scaffolds were implanted bilaterally in lateral thoracic artery flaps (n = 6 rabbits). Right-sided transplants were covered internally with Integra™. In the second series, 10 decellularized tracheae covered with Integra were prelaminated in flaps (n = 10 rabbits). Twenty-one days after implantation, revascularized tracheae were grafted with buccal mucosa. A macroscopic, histological analysis and immunohistochemistry were performed on explants. RESULTS: In the first series, tracheae without Integra covering developed significantly greater intraluminal (P = 0.032) and subepithelial narrowing (P = 0.0345) compared with tracheae with Integra covering. All tracheae exhibited insufficient submucosal revascularization. In the second series, submucosal revascularization was incomplete in the first 2 constructs, which were implanted circularly. These tracheae only showed marginal buccal graft ingrowth. To accelerate revascularization, the subsequent 8 transplants were opened longitudinally before implantation. Compared to circularly implanted tracheae, submucosal revascularization of these transplants was superior (P = 0.0008). Graft adherence was complete in 6 opened constructs. Mild lymphocytic infiltration within the buccal graft was detected in 5 specimens. CONCLUSIONS: We observed satisfactory host integration of opened tracheae that were temporarily covered with Integra during revascularization and subsequently grafted with buccal mucosa. Integra successfully prevented stenosis during revascularization. This model may provide an example of an immunosuppressive-free approach in the treatment of long-segment tracheal lesions. With the aid of further refinements such as a respiratory epithelial lining, an orthotopically transplantable construct could be created.

Tracheal tissue-engineering: in-vivo biocompatibility of mechanically-stripped allogenic rabbit trachea with autologous epithelial covering.

BACKGROUND: Successful trachea transplantation comprises the use of biocompatible constructs with little immune-reactivity, submucosal revascularization and creation of an epithelial covering. Allogenic chondrocytes might be protected from an overt immune-response due to physical isolation. Our aim was to evaluate in-vivo biocompatibility of allotracheae, stripped of their highly-immunogenic inner lining. Secondly, we established whether these constructs might serve as suitable scaffolds for autologous epithelial grafting. METHODS: Mucosa and submucosa of 12 rabbit donor tracheae were mechanically peeled off. Cartilage was covered with Integra™ regeneration-template. Constructs were implanted within the recipient's lateral thoracic artery flap. Integra of 6 revascularized allotracheae was grafted with autologous buccal mucosa. Macroscopical, histological analysis and immunohistochemistry were performed. RESULTS: Revascularization and buccal grafting was incomplete in the first 2 circular constructs. To enhance blood-vessel outgrowth, the following 10 transplants were opened longitudinally before implantation. Integra revascularized well. Grafted tracheae showed satisfactory mucosa-adherence, albeit with invasion of migrating epithelium within the Integra-scaffold. CONCLUSIONS: Mechanically-stripped allotracheae exhibited beneficial biocompatibility up to two months. This approach might open doors in the treatment of long-segment tracheal pathologies of which immunosuppression is contra-indicated. Thickness of this layered construct limited practical feasibility of orthotopic transfer, though with further refinements, a clinically-useful transplant could be created.

Tracheal autotransplantation: guidelines for optimal functional outcome.

OBJECTIVES/HYPOTHESIS: Tracheal autotransplants can repair extensive hemilaryngectomy defects. This technique was introduced into the clinic some 10 years ago as a means of avoiding the mutilation of a total laryngectomy in selected patients with laryngeal cancer. Our goal was to give the morphometric guidelines that guarantee an optimal functional outcome. STUDY DESIGN: Retrospective case study. METHODS: We morphometrically evaluated the structure and function of the larynx after autotransplantation. The close anatomic relationship between the larynx and the trachea made it possible to perform a morphometric analysis of the defect and the repair tissue before and after transplantation. Computed tomography images were used to measure the laryngeal and tracheal airway lumen and the length and width of the tracheal autotransplant. A 4-cm long cartilaginous tracheal transplant was available for reconstruction. RESULTS: Laryngeal repair was achieved with optimal restoration of the airway lumen at all laryngeal levels. We used the maximal amount of trachea that might reasonably be available for autotransplantation. This optimal morphologic repair led to the restoration of speech, swallowing, and respiratory functions. CONCLUSIONS: This study highlights a standardized approach for repairing a hemilaryngeal defect and selecting the appropriate amount of repair tissue. A unique characteristic of vascularized cartilaginous trachea is that it restores the airway lumen after extensive hemilaryngectomy. Tracheal autotransplantation should be included in the armamentarium of reconstructive laryngeal procedures.

Cell-based vascularization strategies for skin tissue engineering.

Providing a blood-vascular network to promote survival and integration of cells in thick dermal substitutes for application in full-thickness wounds is essential for the successful outcome of skin tissue engineering. Nevertheless, promoting vascularization also represents a critical bottleneck in today's skin tissue engineering practice. Several cell types have been considered and tested, mostly in preclinical studies, to increase vascularization. When the clinical situation allows delayed reconstruction of the defect, an autologous approach is preferable, whereas in acute cases allogeneic therapy is needed. In both cases, the cells should be harvested with minimal donor-site morbidity and should be available in large amounts and safe in terms of tumor formation and transmission of animal diseases. Here, we outline the different mechanisms of cell-based vascularization and subsequently elaborate in more detail on the candidate cell types and their pros and cons in terms of clinical application and regulation of the wound healing process.

Nonviral transfection strategies for keratinocytes, fibroblasts, and endothelial progenitor cells for ex vivo gene transfer to skin wounds.

In a search for the optimal nonviral gene transfer technique in epidermal and dermal supportive extracellular matrix studies, we investigated the efficiency of late generation liposomal transfection reagents and nucleofection of fibroblasts (FBs), endothelial progenitor cells (EPCs), and keratinocytes (KCs) as essential indicators of healing skin wounds. FBs, KCs, and EPCs were grown under serum-reduced conditions and manipulated according to optimized in vitro manufacturer protocols. Fugene HD, Effectene, PEI, and Lipofectin were compared to Amaxa Nucleofection. A green fluorescent protein (GFP)-encoded reporter gene plasmid was transfected, and transfection efficiencies were determined by green-fluorescence-activated cell sorting. Normal cell morphologies were observed after either transfection or nucleofection. For KC cell cultures, Fugene HD resulted in the highest transfection efficiency in human (41%) and porcine (42%) KCs. For EPCs, Effectene was optimal for human-derived cells (42%), whereas nucleofection was optimal (32%) for porcine cells. For FBs, however, nucleofection resulted in the highest transfection rates in human (46%) and porcine (60%) FBs. For specific epidermal cell studies, Fugene HD was the preferred gene transfer method, whereas Effectene appeared to be the optimal reagent for pro-angiogenic studies. Nucleofection in combination with FBs is the best combination to achieve the highest overall transfection rate and is thus the optimal combination for use in ex vivo gene transfer strategies of wound healing or skin tissue engineering.

Regulable vascular endothelial growth factor165 overexpression by ex vivo expanded keratinocyte cultures promotes matrix formation, angiogenesis, and healing in porcine full-thickness wounds.

The intricate wound repair process involves the interplay of numerous cells and proteins. Using a porcine full-thickness wound (FTW) healing model, we hypothesized that the ex vivo gene transfer of vascular endothelial growth factor (VEGF)-transfected basal keratinocyte (KC) cell suspensions may generate cross-talk and induce matrix formation, angiogenesis, and accelerated healing. Moreover, to regulate overexpression of isoform 165 of VEGF and its effect on healing, we introduced a tetracycline (TC)-inducible gene switch in the expression plasmid. Autologous basal KCs were cultivated from the porcine donor and transfected using cationic liposomes. A dose-response curve was established to determine optimal activation of the gene switch by TC. In vivo, FTWs were treated with VEGF-transfected KCs and controls. Wound fluids were collected daily and examined using enzyme-linked immunosorbent assay. Biopsies were evaluated using hematoxylin and eosin and immunostaining for fibronectin, CD144, and lectin BS-1. In vitro, highest regulable VEGF165-expression was obtained with 1 microg/mL of TCs. In vivo, after induction of the gene switch by adding 1 microg/mL of TCs to the FTW, we obtained upregulated VEGF165 levels and enhanced fibronectin deposition and found more endothelial cell tubular formations and higher rates of reepithelialization than in controls. This ex vivo gene transfer model may serve as a platform for vascular induction in full-thickness tissue repair.

A novel titanium wound chamber for the study of wound infections in pigs.

In the face of emerging multidrug-resistant microbes, reliable animal models are needed to study potential new therapies in infected wounds. To this end, we implanted screw-top titanium chambers subdermally in full-thickness wounds on both flanks (n = 6 per flank) of 2 Goettinger minipigs. After 1 wk, chambers were inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, or vehicle only. Throughout the study, wound fluid was harvested for quantitative bacterial cultures to monitor infection. Animals were followed for 4 wk, after which tissue biopsies were taken for histologic analysis and quantitative bacterial counts. The implanted titanium chambers were well tolerated by the pigs throughout the study. After inoculation of the chambers, wound infection was established and maintained for 14 d. Despite infection, no systemic effects were noted. Cross-contamination was negligible, compared with the vehicle-only control. After tissue ingrowth, each chamber creates a closed system that allows harvest of exudate or application of substances without loss of material from the chamber. Because 12 chambers are implanted in each pig, researchers have the opportunity to compare multiple treatment options (for example, antibiotics, antimicrobial peptides, gene therapy) in the same animal, with no interindividual variation. We conclude that the use of titanium chambers in pigs provides a reliable and reproducible in vivo model to investigate wound healing, wound infection, and treatment options.

In vivo gene delivery of Ad-VEGF121 to full-thickness wounds in aged pigs results in high levels of VEGF expression but not in accelerated healing.

We have previously reported that endogenous vascular endothelial growth factor (VEGF) concentration in older pig wounds peaked later and at one-fourth the level of young pigs. These data suggested that VEGF might play a major role in the healing of full-thickness wounds in the aged pig. By in vivo gene transfer using the microseeding technique, we treated full-thickness wounds with different doses of VEGF-expressing adenoviral vector (Ad-VEGF) varying from 1 x 10(7) to 2.7 x 10(11) particles per wound (ppw). We found that the VEGF expression in wound fluid followed a dose-response pattern. However, when wounds were microseeded with the highest concentration of Ad-VEGF (2.7 x 10(11) ppw), diminished healing rates were found. We then determined the minimal functional concentrations of Ad-VEGF. We used five aged Yucatan minipigs, all retired breeders, to analyze the role of over-expression of 1 x 10(8) and 1 x 10(9) ppw of Ad-VEGF (n= 78) in terms of healing of full-thickness wounds, all 2.5 x 2.5 x 1 cm in size (n= 158). The Ad-VEGF solutions were delivered to the wound floor and borders by in vivo microseeding. Control wounds (n= 80) were microseeded with Ad-Lac-Z (n= 25), treated with saline (n= 49) or treated dry (n= 6). All wounds except for the dry-treated ones were covered with a wound chamber and a wet environment was created by injecting 2.5 ml saline into the chamber. Peak VEGF expression (2300-4000 pg/ml) was detected on days 2 or 3 post gene delivery. This level of VEGF expression was not seen in the saline (n= 49) or Ad-null (n= 25) control groups. The VEGF expression in wounds treated with 1 x 10(8) and 3 x 10(8) ppw (n= 39) exhibited a slower onset with a peak concentration of 400-920 pg/ml on days 5-7. Although high levels of VEGF expression were achieved in the local wound environment, we could not show a significant increase in neovascularization as compared to saline-treated wounds. No significant differences were observed in the rate of reepithelialization and wound contraction among groups of full-thickness wounds treated with Ad-VEGF, Ad-null mutant, or saline in the aged "wet wound healing" pig model. These results indicate that increased levels of VEGF in wounds produced by in vivo gene transfer have little effect on the healing of full-thickness wounds in the aged pig model. Moreover, significantly higher levels of VEGF expression by Ad-VEGF could lead to impaired wound healing.

Wet wound healing.

Wound treatment in a flexible transparent chamber attached to the perimeter of the wound and containing a liquid has been extensively tested in preclinical experiments in pigs and found to offer several advantages. It protects the wound; the liquid medium or saline in the chamber provides in vivo tissue culture-like conditions; and antibiotics, analgesics, and various molecules can be delivered to the wound through the chamber. The wound chamber causes no injury to the wound itself or to the surrounding intact skin. Topical delivery of, for instance, antibiotics can provide very high concentrations at the wound site and with a favorable direction of the concentration gradient. A series of 28 wounds in 20 patients were treated with a wound chamber containing saline and antibiotics. Most patients had significant comorbidity and had not responded to conservative or surgical management with débridement and delayed primary closure or skin grafts. Six wounds had foreign bodies present; four of these were joint prostheses. Seven patients were on corticosteroids for rheumatoid arthritis, lupus, or chronic obstructive pulmonary disease, and four patients had diabetes. Most patients were treated with the wound chamber in preparation for a delayed skin graft or flap procedure, but one was treated with a wound chamber until the wound healed. Twenty-five of the wounds (89 percent) healed, and five wounds (18 percent) required additional conservative management after the initial chamber treatment and grafting procedure. Of the three wounds that did not heal, one healed after additional chamber treatment, one had a skin graft that did not take, and one required reamputation at a higher level. Antibiotic delivery was less than one intravenous dose daily, which avoided the potential for systemic absorption to toxic levels. Antibiotics such as vancomycin and gentamicin could be used in concentrations of up to 10,000 times the minimal inhibitory concentration. Forty-eight hours after application, 20 percent or more of the original antibiotic concentration was present in the wound chamber fluid. In conclusion, the wound chamber provides a safe, powerful tool in the treatment of difficult infected wounds.

Perforator topography of the deep inferior epigastric perforator flap in 100 cases of breast reconstruction.

The anatomic topography of the perforators within the rectus muscle and the anterior fascia largely determines the time needed to harvest the perforator free flap and the difficulty of the procedure. In 100 consecutive cases, the topographic patterns of the perforators were investigated. In 65 percent, a short intramuscular course was seen. In 16 percent, a perforator at the tendinous intersection was encountered. In 9 percent, the largest perforator was found to have a long intramuscular course. In 5 percent, a subfascial course was found, and in another 5 percent, a paramedian course was found. In 74 percent of flaps, just one perforator was used, whereas two perforators were dissected in 20 percent. Only in 6 percent of flaps were three perforators used. A long intramuscular course (>4 cm) lengthens the dissection substantially, especially when the intramuscular course is in a step-wise pattern. The subfascial course requires precarious attention at the early stage of the perforator dissection when splitting the fascia. The perforators at the tendinous intersections are the most accessible and require a short but intense dissection in the fibrotic tissue of intersection. A paramedian perforator, medial to the rectus muscle, is a septocutaneous rather than a musculocutaneous perforator. The straightforward dissection almost extends up to the midline. Therefore, dissection always is performed at one side and, if no good perforators are present, continued at the intact contralateral side. The size of these perforators and their location in the flap determine the choice. One perforator with significant flow can perfuse the whole flap. If in doubt, two perforators can be harvested, especially if they show a linear anatomy so that muscle fibers can be split. The only interference with the muscle exists in splitting the muscle fibers. A perforator that lies in the middle of the flap is preferable. For a large flap, a perforator of the medial row provides better perfusion to zone 4 than one of the lateral row because of the extra choke vessel for the lateral row perforators. The clinical appearance of the perforators is the key element in the dissection of the perforator flap. Perforator topography determines the overall length and difficulty of the procedure.