Safe ischemia time in free-flap surgery: a clinical study of contact-surface cooling

Fibula Free Flap Salvage From 10-hour Prolonged Arterial Insufficiency and Venous Thrombosis

ABSTRACT

Fibula free flaps are standard in facial reconstructions after head and neck cancer resection and typically have short flap ischemia times, often under 2 hours. Methods for short-term flap ischemia are characterized, but methods for extremely prolonged flap ischemia have not been well-described. We describe a 72-year-old patient who underwent composite floor of mouth and mandible resection with fibula free flap reconstruction. Patient intraoperative instability forced flap ischemia of over 10 hours with arterial insufficiency and venous thrombosis. Despite complicated and extremely prolonged ischemia, aggressive local and systemic anticoagulants with intraoperative leach therapy were still effective in flap salvage. The flap ultimately survived without necrosis. This case describes a method to guide surgeons faced with situations of forced, prolonged flap ischemia. Traditionally indicated in short-term ischemia, anticoagulation and leach methods can be effective for intraoperative treatment of extremely prolonged flap ischemia, arterial insufficiency, and venous thrombosis.

In vivo perfusion of free skin flaps using extracorporeal membrane oxygenation

BACKGROUND

The vessel-depleted, irradiated, and frozen neck, as well as severe atherosclerosis of recipient vessels represent challenging problems in free flap transfer. Extracorporeal free flap perfusion theoretically allows free flap reconstructions in the absence of local donor vessels, but is associated with a number of technical issues. In this study, a novel technique is presented using a commercially available system for extracorporeal membrane oxygenation (ECMO), modified for small blood volumes.

METHODS

After preclinical testing, an ECMO system certified for lung support was used to establish blood flow through the flap's artery with oxygenation, decarboxylation and warming of diluted packed blood cells. Venous blood was allowed to flow passively into a separate container. Perfusion was performed for 15 min at intervals of 4 h over 4-6 days.

RESULTS

Five patients with soft tissue defects requiring free flap reconstruction were included. Either primarily thinned anterolateral thigh (ALT) flaps (n = 3) or radial forearm flaps (n = 2) were used. We observed infection of the perfusate, with consequent subtotal flap loss, in one patient, complete epithelial loss in two patients, venous congestion in one case, and almost uneventful healing in the fifth patient. With conservative wound care and a split thickness skin graft in one case, stable wound coverage was achieved in all patients except one, who had secondary healing. None of the patients required a second flap for sufficient coverage.

CONCLUSIONS

The technique described is associated with the risks of infection, flap congestion, nutritive hypoperfusion, and consequent tissue loss. Nevertheless, stable defect closure seems to be achievable even in patients with depleted recipient vessels.

Contact Cooling of Random-Pattern Cutaneous Flaps: Does it Increase Necrosis?

BACKGROUND

Cooling after surgery reduces pain, swelling and ecchymosis. However, the fear of adverse effects of vasoconstriction caused by cooling may prevent its use when the skin is undermined extensively, for example, after rhytidectomy. The purpose of this study is to determine whether the contact cooling of random-pattern skin flaps increases the area of necrosis observed.

METHODS

Twenty-eight random-pattern skin flaps (4 × 10 cm) were raised on four pigs. Flaps were divided into three groups: control, intermittently cooled and continuously cooled. Pads connected to a ThermaZone cooling device delivered local hypothermia in the range of 4-6 °C for 24 h postoperatively. ImageJ software was used to calculate the area of necrosis on each flap on postoperative day 7, confirmed with histological analysis.

RESULTS

The average areas of necrosis observed were as follows: control (17.61 cm²; SD 5.23), intermittent cooling (15.65 cm²; SD 3.76) and continuous cooling (14.16 cm²; SD 3.91). An ANOVA revealed no statistically significant differences between the three interventions (p = 0.35).

CONCLUSIONS

Postoperative continuous or intermittent cooling does not increase the area of necrosis in random-pattern flaps. In fact, a trend was observed, demonstrating decreasing area of necrosis with increased periods of hypothermia.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors. www.springer.com/00266 .

A new method for skin grafting in murine model

Skin transplantation provides an excellent potential model to investigate the immunology of allograft rejection and tolerance induction. Despite the theoretical ease of performing skin transplantation, as well as the potential of directly observing the reaction to the transplanted tissue, the poor reliability of skin transplantation in the mouse has largely precluded the use of this model. Furthermore, there is controversy regarding the most appropriate skin graft donor site due to poor success of back skin transplantation, as compared with the thinner ear or tail skin. This study demonstrates a reliable method to successfully perform skin grafts in a mouse model, as well as the clinical and histologic outcome of syngeneic grafts. A total of 287 grafts were performed (in 126 mice) utilizing donor skin from the ear, tail or back. No graft failure or postoperative mortality was observed. Comparison of this technique with two previously established protocols of skin transplantation (5.0 absorbable Suture + tissue glue technique and no-suture technique) demonstrates the significant improvement in the engraftment success of the new technique. In summary, a new technique for murine skin grafting demonstrates improved reliability across donor site locations and strains, increasing the potential for investigating interventions to alter the rejection process.

Long term study into surgical re-exploration of the 'free flap in difficulty'

BACKGROUND

Free tissue transfers must survive in order to achieve their surgical goals. There is little consensus about managing the 'failing' free flap, and practice is often guided by anecdote.

MATERIAL AND METHODS

We have prospectively collected data about all free flaps performed within our department between 1985 and 2008 (2569 flaps). We identified 327 flaps which were re-explored a total of 369 times. We analysed these flaps with regard to indication for re-exploration, operative findings and outcome.

RESULTS

Thirteen percent (327) of free flaps were re-explored. Of these, 291 (83%) had a successful outcome. Successful re-explorations took place at a mean 19h post-op and unsuccessful re-explorations at a mean 56h post-op. Clinical diagnosis prior to re-exploration was confirmed operatively in 91% of cases.

CONCLUSION

We have considered the factors that allowed us to achieve the salvage rates described over a prolonged period, and identified two key areas. Firstly, we favour a model for free flap monitoring with clinical judgement at its core. Secondly, we feel the facility to recover patients post-operatively in a specialised, warmed environment, and return them to theatre quickly should the need arise, is essential. These two simple, yet institutionally determined factors are vital for maintaining excellent success rates.

Simultaneous Bilateral Breast Reconstruction With Superior Gluteal Artery Perforator (SGAP) Flaps

The superior gluteal artery perforator (SGAP) flap is a useful technique for restoration of the breast after mastectomy. If appropriately planned, the soft-tissue envelope supplied by the superior gluteal artery perforator vessels can be harvested with minimal donor site morbidity and often results in a highly esthetic restoration of the breasts. Dissection of the flap is performed with complete preservation of gluteus maximus muscle function. The resulting vascular pedicle obtained via dissection through the muscle is longer than that of gluteal musculocutaneous flaps and affords the surgeon the luxury of avoiding vein grafts in the anastomotic phase of surgery. Despite these advantages, use of the SGAP flap is not popular among reconstructive surgeons. Many practitioners are not familiar with the vascular anatomy of the gluteal area and may not be comfortable with the dissection of the parent vessels or lack the desire to practice microsurgery. On the other hand, our group has reported the largest experience to date with this method of breast reconstruction and has found the SGAP flap to be a reliable and safe method of autologous breast restoration in unilateral absence of the breast. Although the indications to perform single-stage gluteal tissue transplantation for bilateral breast restoration are uncommon, they do occasionally arise in clinical practice. We have carried out concurrent bilateral breast reconstruction using SGAP flaps on 6 patients with acceptable overall morbidity. All flaps went on to survive and resulted in highly esthetic restorations of the breast. Though a challenging undertaking, in-unison transfer of bilateral SGAP flaps serves as a useful option for a subset of patients desiring 1-stage bilateral breast reconstruction.