Identification of perioperative risk factor by laser-doppler spectroscopy after free flap perfusion in the head and neck: A prospective clinical study

Abstract

The aim of this study was to evaluate perioperative flap perfusion using noninvasive monitoring with a laser-Doppler flowmetry and spectrophotometry unit (O2C) and identify whether perioperative blood flow, velocity, hemoglobin level (Hb), and oxygen saturation (SO2 ) measured could be used as indicators of free flap success. Measurements of blood flow, velocity, Hb, and SO2 were performed in 196 microvascular flaps, which had been transferred into the oral cavity to reconstruct ablative defects after surgery for oral cancer. The values were calculated superficially on the skin surface and at a depth of 8 mm. The results showed that perioperative absolute values measured were not associated with an increased rate of microvascular revisions or free flap failure. Independent predictors of microvascular revisions at the first postoperative day were the development of a falling trend in superficial and deep blood flow, and velocity in comparison with baseline values of variables measured. On day 2, all superficial and deep values of Hb, flow, and velocity were independent prognostic factors (P < 0.01), demonstrated as a downward trend were associated with a need for revision. The superficial and deep values of SO2 (P = 0.59 and 0.43, respectively) were not associated with ultimate free flap failure. This is the first clinical study to demonstrate that during early free flap integration to the recipient site different parameters of perfusion and oxygenation play an important role at different points of time. Within the first two postoperative days, changes in these parameters can help influence the decision to revise microvascular anastomoses.

Impact of increasing operative time on the incidence of early failure and complications following free tissue transfer? A risk factor analysis of 2,008 patients from the ACS‐NSQIP database

“…Possible explanations for this link include an associated greater case complexity, higher blood loss, fluid shifts, depressed wound healing capability, and vessel/tissue desiccation . A recent study by Mücke et al revealed that perioperative blood flow, velocity, hemoglobin level, and oxygen saturation might be critical determinants of flap viability during the immediate 48 hours postoperative period. Although the study authors did not suggest specific values for any of these parameters that would otherwise be indicative of flap failure, there might be considerable utility in trending and addressing these parameters intraoperatively and during the postoperative free flap monitoring.…”

Current Evidence for Postoperative Monitoring of Microvascular Free Flaps

“…One advantage of this technique is that scintigraphy images can show areas of partial flap hypoperfusion. Several different isotopes have been studied, 147,[198][199][200][201] including 85 Kr, 133 Xe, 22 Na, and 99m Tc. Aygit and Sarikaya 200 demonstrated that this technique was useful in determining flap viability, but note was made of several problems with this technique, making it ultimately unlikely to be useful in monitoring of flaps.…”

“…134 This technique was later easily adapted for use in monitoring free flaps. The introduction of fiberoptic fluorometry by Silverman et al 133,134 allowed for the monitoring of elimination as well as perfusion with fluorescein. [135][136][137] Subsequently, other studies showed that using oral fluorescein was possible.…”

Monitoring Vascular Compromise Using Ultrasound After Free Tissue Transfer

“…In recent years, various new monitoring tools allowing an earlier diagnosis of vascular compromise than conventional bedside monitoring have reportedly improved the flap salvage rates, resulting in improved success rates. New monitoring tools include implantable Doppler systems that allow direct monitoring of vascular anastomotic sites, noninvasive monitoring using near‐infrared spectroscopy, invasive monitoring of metabolic products such as lactic acid levels using microdialysis, and laser Doppler flowmetry …”