Porcine xenograft and second intention healing on the lower extremities after Mohs surgery: a descriptive case series

There is limited data on benefits of healing after Mohs surgery using porcine xenografts (PXs) compared to second intention (SI). This case series sought to describe healing time, scar size, cosmetic outcome, pain, and infection rates in patients treated with PX or SI for wounds on lower extremities. 14 patients were enrolled. Six patients received treatment with SI, and eight patients received PX. 11 patients (4 SI, 7 PX) completed follow-up visit after 3 months (79% follow-up rate) when primary outcome measure was assessed. 64% of patients took > 3 months to heal. 72% of patients healed within 6 months post-surgery. Scars contracted by > 50% in 7/11 patients completing follow-up. In SI group, 3/5 patients self-reported pain level > 1 out of 10 at 1-week post-surgery compared to 3/8 in the PX group. Two patients in each group developed post-operative wound infection and three patients in PX group experienced other adverse events. These results suggest that healing with PX or SI resulted in small scar size, low post-operative pain level, and low rate of adverse events. Both groups had longer healing times than expected.

Longitudinal histomechanical heterogeneity of the internal thoracic artery

The internal thoracic artery (ITA) is the principal choice for coronary artery bypass grafting (CABG) due to its mechanical compatibility, histological composition, anti-thrombogenic lumen, and single anastomotic junction. Originating at the subclavian artery, traversing the thoracic cavity, and terminating at the superior epigastric and musculophrenic bifurcation, bilateral ITAs follow a protracted circuitous pathway. The physiological hemodynamics, anatomical configuration, and perivascular changes that occur throughout this length influence the tissue's microstructure and gross mechanical properties. Since histomechanics play a major role in premature graft failure we used inflation-extension testing to quantify the regional material and biaxial mechanical properties at four distinct locations along the left (L) and right (R) ITA and fit the results to a structurally-motivated constitutive model. Our comparative analysis of 44 vessel segments revealed a significant increase in the amount of collagen but not smooth muscle and a significant decrease in elastin and elastic lamellae present with distance from the heart. A subsequent decrease in the total deformation energy and isotropic contribution to the strain energy was present in the LITA but not RITA. Circumferential stress and compliance generally decreased along the length of the LITA while axial stress increased in the RITA. When comparing RITAs to LITAs, some morphological and histological differences were found in proximal sections while distal sections revealed differences predominantly in compliance and axial stress. Overall, this information can be used to better guide graft selection, graft preparation, and xenograft-based tissue-engineering strategies for CABG.

Decellularized porcine xenograft for anterior cruciate ligament reconstruction: A histological study in sheep comparing cross-pin and cortical suspensory femoral fixation

Aims

To evaluate graft healing of decellularized porcine superflexor tendon (pSFT) xenograft in an ovine anterior cruciate ligament (ACL) reconstruction model using two femoral fixation devices. Also, to determine if pSFT allows functional recovery of gait as compared with the preoperative measurements.

Methods

A total of 12 sheep underwent unilateral single-bundle ACL reconstruction using pSFT. Two femoral fixation devices were investigated: Group 1 (n = 6) used cortical suspensory fixation (Endobutton CL) and Group 2 (n = 6) used cross-pin fixation (Stratis ST). A soft screw was used for tibial fixation. Functional recovery was quantified using force plate analysis at weeks 5, 8, and 11. The sheep were euthanized after 12 weeks and comprehensive histological analysis characterized graft healing at the graft-bone interface and the intra-articular graft (ligamentization).

Results

The pSFT remodelled into a ligament-like structure and no adverse inflammatory reaction was seen. The ground reaction force in the operated leg of the Endobutton group was higher at 11 weeks (p < 0.05). An indirect insertion was seen at the graft-bone interface characterized by Sharpey-like fibres. Qualitative differences in tendon remodelling were seen between the two groups, with greater crimp-like organization and more aligned collagen fibres seen with Endobutton fixation. One graft rupture occurred in the cross-pin group, which histologically showed low collagen organization.

Conclusion

Decellularized pSFT xenograft remodels into a ligament-like structure after 12 weeks and regenerates an indirect-type insertion with Sharpey-like fibres. No adverse inflammatory reaction was observed. Cortical suspensory femoral fixation was associated with more enhanced graft remodelling and earlier functional recovery when compared with the stiffer cross-pin fixation.

Burn scar outcome at six and 12 months after injury in children with partial thickness scalds: Effects of dressing treatment

INTRODUCTION

In line with other researchers in the field of burns' care, we think that research investigating the long-term outcome of scars is largely lacking. As scarring is of the utmost importance to the patient, clinicians who treat burns must aim to find treatments that lead to a good end result. The aim of this study was to study scar outcomes at six and 12 months after injury. It is an extension of a previous randomised controlled trial (RCT) in which two dressings (porcine xenograft and silver foam dressing) were examined with respect to their ability to help heal partial thickness scalds.

METHOD

Children aged six months - six years with acute partial thickness scalds, on the trunk, or extremities, or both, were included. In the previous study, the silver foam was found to have significantly shorter healing times than the xenograft. Children were assessed at six and 12 months after injury for this study, and photographs were taken of the burn site, and both the patient and observer scar assessment scale (POSAS) and the Vancouver scar scale (VSS) were completed and evaluated by blinded observers.

RESULTS

Of the 58 children from the original RCT, 39 returned to the clinic for evaluation of their scars at six months, and 34 at 12 months after injury. There were no differences in POSAS, VSS total scores, or incidence of hypertrophic scarring between the different dressings. Fifteen children were assessed as having hypertrophic scarring, all of whom had healing times that had extended beyond 14 days.

CONCLUSIONS

This study compared burn scarring after two different treatments for burns in children with partial-thickness scalds and the data suggested that neither dressing had a more favourable impact on scar outcome. The conclusion is, however, tempered by the non-return of all the patients to the follow up. However, as anticipated, regardless of the dressing used, longer healing times were associated with higher scar scores (more scarring) and hypertrophic scarring.

Reconstruction of a surgical defect in the popliteal fossa: A case report

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Popliteal tumors and their associated defects present the dermatologic surgeon with rare and unique surgical and reconstruction challenges.

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When planning reconstruction in the popliteal fossa, prolonged wound care and functional impairment are concerns.

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In such an area with little tissue laxity, a random patterned bilobed with an undersized secondary lobe is an excellent solution to this challenge.

Introduction

Surgical defects of the popliteal fossa pose a reconstructive challenge to the surgeon, given the intimate relationship of this area with the knee joint and underlying vital neuro-vasculature.

Case presentation

An 88-year-old woman was treated for a biopsy proven invasive squamous cell carcinoma of the right popliteal fossa with Mohs micrographic surgery. The resultant defect (4.5 × 4.3 cm) was repaired using a random patterned bilobed flap with an undersized secondary lobe and porcine xenograft with excellent functional and cosmetic outcome.

Discussion

Numerous approaches to reconstruction of the popliteal fossa have been proposed, including primary closure, secondary intent healing, skin grafting, random flaps, muscle flaps, fasciocutaneous flaps, freeflaps, and tissue expansion. Sub-optimal repair of the popliteal fossa can reduce mobility of the knee joint, carry a high risk of wound dehiscence and may result in significant scarring. Here, we present the use of a bilobed flap with an undersized secondary lobe, in a patient with limited tissue laxity, for the repair of the popliteal fossa.

Conclusion

Utilizing a random pattern bilobed flap with an undersized secondary lobe is an excellent alternative for the repair of moderate sized popliteal fossa defects.

Surgical management of late-term pulmonary venous baffle stenosis after Senning operation

Although pulmonary venous baffle stenosis is not a common late complication after the Senning operation, surgical treatment is vital, when interventional methods fail to correct the pathology. Our patient was admitted to hospital with recurrent epistaxis and exertional dyspnea 6.5 years after the Senning procedure. The gradient in the pulmonary venous baffle was measured as 34 to 35 mmHg via transthoracic echocardiography. During surgical treatment, the calcified and retracted polytetrafluoroethylene flap was completely excised and porcine pericardial xenograft was used to cover the pulmonary venous baffle. At the end of the procedure, no significant gradient was detected via transesophageal echocardiography.

Porcine xenografts vs. (cryopreserved) allografts in the management of partial thickness burns: is there a clinical difference?

Porcine xenografts and cryopreserved allografts are used for the management of partial thickness burns and both biological materials have strong advocates with regard to clinical performance, the possibility of disease transfer from donor to recipient and other clinical aspects. A literature analysis was performed in an attempt to investigate whether true (statistically significant) differences exist on clinical performance and on other determinants for use. Comparing the results of this study with a similar, previously published study performed on possible differences amongst different types of allograft in the management of partial thickness burns, both allografts and porcine xenograft seem to perform equally well clinically with regard to healing related outcomes. In addition, the risk of disease transfer, in real life, was shown to be minimal. Consequently, clinical aspects being equal, other aspects such as price and availability should be used to decide which material to use for the management of partial thickness burns.