ABSTRACT
BACKGROUND: The reconstruction of extensive tracheal defects is an unresolved problem. Despite decades of research, a reliable and practical substitute remains to be found. While there have been clinical reports of successful long-segment tracheal reconstruction, reproducibility and widespread applicability of these techniques have yet to be achieved. Large animals such as the dog, pig, sheep, and goat have comparable tracheal morphology and physiology to humans making them useful preclinical models to screen potential therapeutic strategies. MATERIALS AND METHODS: The literature was reviewed to identify large animal models commonly used for tracheal reconstruction. A systematic search of PubMed and EMBASE was performed for large animal studies reporting on the reconstruction of long-segment tracheal and carinal defects. Fifty-seven studies were identified for analysis. RESULTS: There is no standard large animal model available for tracheal research. In recent years, livestock species have gained favor over dogs as animal models in this field. The minimum requirements for successful tracheal replacement are rigidity, vascularity, and epithelial lining. Early attempts with synthetic prostheses were met with disappointing results. An autologous tracheal substitute is ideal but hindered by limited donor site availability and the lack of a dominant vascular pedicle for microsurgical reconstruction. Although tracheal allotransplantation enables like-for-like replacement, there are unresolved issues relating to graft vascularity, immunosuppression, and graft preservation. Tissue engineering holds great promise; however, the optimal combination of scaffold, cells, and culture conditions is still indeterminate. CONCLUSIONS: Despite impressive advances in tracheal reconstruction, a durable substitute for extended tracheal defects continues to be elusive.
Subject(s)
Models, Animal , Trachea/transplantation , AnimalsABSTRACT
BACKGROUND: The nasolabial flap is ideal for reconstruction of the nasal alar subunit due to its proximity, color and contour match, and well-placed donor scar. When raised as a random-pattern flap, there is a risk of vascular compromise to the tip with increased flap length and aggressive flap thinning. Surgical delay can greatly improve the chances of tip survival, allowing the harvest of longer flaps with greater reach. METHODS: We describe our technique of lengthening the nasolabial flap through multiple delay procedures. A bipedicled flap was first raised and then transferred as a unipedicled flap with a 6:1 length-to-width ratio. During the delay process, the flap tip was thinned to the subdermal layer. RESULTS: In our case series of seven patients, defects as far as the medial canthal area and contralateral ala were reconstructed successfully with no incidence of tip necrosis or flap loss. The resultant flaps were thin enough to be folded over for the reconstruction of alar rim defects. CONCLUSIONS: We highlight the success of our surgical technique in creating thin and robust nasolabial flaps for the reconstruction of full-thickness defects around the nose.
ABSTRACT
Free flap tissue transfer has become the gold standard for reconstruction of composite head and neck defects. We sought to investigate the efficacy and morbidity of these procedures in the elderly. We retrospectively reviewed 245 head and neck free flap procedures (234 patients). Patients were stratified by age group (≥ or <65 years). Univariate and multivariate analyses were used to evaluate the following primary outcomes - free flap survival, postoperative medical and surgical complications and 30-day mortality. We found that free flap success and surgical complication rates were similar between the two age groups. Overall flap success and perioperative mortality rates were 94.3% and 2.1% respectively. Medical complications were significantly more common in the elderly group (p <0.001) and this correlated with comorbidity (OR = 2.81, p = 0.044) and advanced tumour stage (OR = 10.20, p= 0.029). Age was not independently associated with poor outcomes in our cohort. We then performed a systematic review of similar case-control studies worldwide and compared their findings with our results. We conclude that advanced age does not preclude free flap success in head and neck reconstruction. Rather, the presence of comorbidity appears to predict the development of medical complications postoperatively. Elderly patients with low comorbidity scores may be offered free flap reconstruction with less reservation.
