Video Tutorial for Clinical Flap-Monitoring in Plastic Surgery

[The conjoined latissimus dorsi and parascapular free flap for reconstruction of extensive soft tissue defects]

OBJECTIVE

Durable and resilient soft tissue reconstruction of vast defects of the extremities or the torso.

INDICATIONS

Reconstruction of disproportionately large defects, particularly in cases of simultaneous bone and joint reconstruction.

CONTRAINDICATIONS

History of surgery or irradiation of upper back and axilla, impossibility of surgery under lateral positioning; relative contraindications in wheelchair users, hemiplegics, or amputees.

SURGICAL TECHNIQUE

General anesthesia and lateral positioning. First, the parascapular flap is harvested, with the initial skin incision made medially in order to identify the medial triangular space and the circumflex scapular artery. Flap raising then proceeds from caudal to cranial. Second, the latissimus dorsi is harvested, with the lateral border being dissected free first, before the thoracodorsal vessels are visualized on its undersurface. Flap raising then proceeds from caudal to cranial. Third, the parascapular flap is advanced through the medial triangular space. If the circumflex scapular and thoracodorsal vessels originate separately from the subscapular axis, an in-flap anastomosis is warranted. Subsequent microvascular anastomoses should be performed outside the zone of injury, typically in an end-to-end fashion of the vein and end-to-side fashion of the artery.

POSTOPERATIVE MANAGEMENT

Postoperative anticoagulation with low-molecular-weight heparin under anti-Xa monitoring (semitherapeutic in normal-risk and therapeutic in high-risk cases). Hourly clinical assessment of flap perfusion for 5 consecutive days, followed by stepwise relaxation of immobilization and commencement of dangling procedures in cases of lower extremity reconstruction.

RESULTS

Between 2013 and 2018, 74 conjoined latissimus dorsi and parascapular flaps were transplanted to cover vast defects of the lower (n = 66) and upper extremity (n = 8). The mean defect size was 723 ± 482 cm² and the mean flap size was 635 ± 203 cm². Eight flaps required in-flap anastomoses for separate vascular origins. There was no case of total flap loss.

Postoperative free flap monitoring in reconstructive surgery-man or machine?

Free tissue transfer is widely used for the reconstruction of complex tissue defects. The survival of free flaps depends on the patency and integrity of the microvascular anastomosis. Accordingly, the early detection of vascular comprise and prompt intervention are indispensable to increase flap survival rates. Such monitoring strategies are commonly integrated into the perioperative algorithm, with clinical examination still being considered the gold standard for routine free flap monitoring. Despite its widespread acceptance as state of the art, the clinical examination also has its pitfalls, such as the limited applicability in buried flaps and the risk of poor interrater agreement due to inconsistent flap (failure) appearances. To compensate for these shortcomings, a plethora of alternative monitoring tools have been proposed in recent years, each of them with inherent strengths and limitations. Given the ongoing demographic change, the number of older patients requiring free flap reconstruction, e.g., after cancer resection, is rising. Yet, age-related morphologic changes may complicate the free flap evaluation in elderly patients and delay the prompt detection of clinical signs of flap compromise. In this review, we provide an overview of currently available and employed methods for free flap monitoring, with a special focus on elderly patients and how senescence may impact standard free flap monitoring strategies.

Do-It-Yourself Preoperative High-Resolution Ultrasound-Guided Flap Design of the Superficial Circumflex Iliac Artery Perforator Flap (SCIP)

The superficial circumflex iliac artery perforator (SCIP) flap is a well-documented, thin, free tissue flap with a minimal donor site morbidity, and has the potential to become the new method for resurfacing moderate-size skin defects. The aim of this study is to describe an easy, reliable, systematic, and standardized approach for preoperative SCIP flap design and perforator characterization, using color-coded duplex sonography (CCDS). A list of customized settings and a straightforward algorithm are presented, which are easily applied by an operator with minimal experience. Specific settings for SCIP flap perforator evaluation were investigated and tested on 12 patients. Deep and superficial superficial circumflex iliac artery (SCIA) branches, along with their corresponding perforators and cutaneous veins, were marked individually with a permanent marker and the anatomy was verified intraoperatively. From this, a simplified procedure for preoperative flap design of the SCIP flap was developed. Branches could be localized and evaluated in all patients. A preoperative structured procedure for ultrasonically guided flap design of the SCIP flap is described. A 100% correlation between the number and emergence points of the branches detected by preoperative CCDS mapping and the intraoperative anatomy was found.

A paintable phosphorescent bandage for postoperative tissue oxygen assessment in DIEP flap reconstruction

Flaps are common in plastic surgery to reconstruct large tissue defects in cases such as trauma or cancer. However, most tissue oximeters used for monitoring ischemia in postoperative flaps are bulky, wired devices, which hinder direct flap observation. Here, we present the results of a clinical trial using a previously untried paintable transparent phosphorescent bandage to assess the tissue's partial pressure of oxygen (pO2). Statistical analysis revealed a strong relationship (P < 0.0001) between the rates of change of tissue oxygenation measured by the bandage and blood oxygen saturation (%stO2) readings from a standard-of-care ViOptix near-infrared spectroscopy oximeter. In addition, the oxygen-sensing bandage showed no adverse effects, proved easy handling, and yielded bright images across all skin tones with a digital single-lens reflex (DSLR) camera. This demonstrates the feasibility of using phosphorescent materials to monitor flaps postoperatively and lays the groundwork for future exploration in other tissue oxygen sensing applications.

Transcutaneous oxygen measurement using ratiometric fluorescence imaging as a valid method for monitoring free flap transplants

BACKGROUND

Reconstruction of soft tissue defects with free flaps is a common procedure in plastic and reconstructive surgery. Most postoperative complications occur within the first 48-72 hours after surgery. After postoperative complications, short perfusion restoration times may improve flap survival rates by up to 30-50%. Ratiometric fluorescence imaging is an additional or alternative method of postoperative flap monitoring.

OBJECTIVE

To test the efficacy and utility of transepidermal oxygen flux imaging to evaluate postoperative skin oxygenation of free and local flaps in the first 48 hours after surgery.

METHODS

The study included 32 patients (aged between 18 and 80 years; mean age 52.9) with a tissue defect covered with a free flap transplant at the Department of Plastic and Reconstructive Surgery of the University Medical Center Regensburg. Postoperative oxygen flux was measured with the 'VisiSens system' placed on the vascular pedicle as well as on the peripheral and central part of the flap.

RESULTS

Values of oxygen flux were higher in case of flap congestion (0.069±0.012) or flap necrosis (0.155±0.083) than in cases without any complications (0.061±0.006). Flux values of different areas of the same flap showed only minimal differences (central part: 0.065±0.008, peripheral part: 0.070±0.009, vascular pedicle: 0.056±0.004); the level of significance was p = 0.904.

CONCLUSION

Imaging transepidermal oxygen flux by ratiometric luminescence seems to be a reliable alternative, indirect method of postoperative flap monitoring with regard to microcirculatory function and flap viability.