A comparative analysis using flowmeter, laser-Doppler spectrophotometry, and indocyanine green-videoangiography for detection of vascular stenosis in free flaps

Abstract

The effects of gradual vascular occlusion on the blood supply of perfused areas are poorly described. Information relating to the comparison of flap monitoring techniques is lacking. Varying stenotic conditions (0%, 25%, 50%, 75% and 100%) were generated on purpose at the A. and V. femoralis in the rat model. Analyses included flowmeter, simultaneous laser-Doppler flowmetry and tissue spectrophotometry (O2C) and indocyanine green-(ICG-) videoangiography with integrated FLOW 800 tool. A Random Forests prediction model was used to analyse the importance of each method to diagnose the stenotic conditions. The ability to discriminate and to accurately estimate the probability of stenosis was assessed by Receiver Operating Characteristic (ROC) curves and calibration plots. Blood flow changes for all modalities were described in detail. Flowmeter displayed earliest a linear decrease as a result of increasing stenosis. A stenosis of 50% degrees was most difficult to detect correctly. The combination of flowmeter and ICG-videoangiography showed high diagnostic power for each stenotic situation (area under the Roc > 0.79). Flowmeter and ICG-videoangiography showed to be most relevant in detection of varying stenotic conditions and may change the clinical outcome. The O2C showed less effect on varying stenotic situations as the only surface monitoring device. The microvascular free tissue transfer has revolutionised reconstructive microsurgery and has improved the patients' functional outcome 1. Despite the well documented co-morbidities of patients undergoing head and neck surgery, free flap surgery has contributed to a continuous improvement in the patient-reported and clinical outcomes 2-4. Due to the significant patient co-morbidities and the complexity of the operations, this patient cohort has a high free flap failure rate. A successful outcome necessitates a detailed pre-, intra-and postoperative patient screening in addition to the free flap monitoring, for at least the first 72 hours, postoperatively. The reasons for free flap failures are commonly vascular (thrombosis, endothelial damage) or extravascular, (hematoma, kinking, twisting) in origin. Flap necrosis invariably leads to a prolonged hospital stay and may result in mortality due to poor physiological reserves. There is a definitive window of surgical intervention that must not be missed, for the salvage operation to be successful 5,6. For this reason, the routine postoperative free flap monitoring has to be effective, reproducible and reliable. Free flap monitoring techniques vary and may include the clinical observation, pinprick testing and handheld Doppler 7. More sophisticated, objective methods include simultaneous

Head and neck pedicled flap autonomization using a new high‐resolution indocyanine green fluorescence video‐angiography device

“…To date, no specific techniques are known to predict the perfusion of pedicled flaps in head and neck reconstructive surgery as properly as ICG video‐angiography. Despite adding additional costs, 8 it may allow earlier second‐stage pedicle division leading to reduction of costs (outpatient dressings and consultations, donor site morbidity) and duration of esthetic deformity for patients 7 . The new high‐resolution device that we have employed adds further accuracy to the traditional ICG video‐angiography, providing a real‐time flap‐to‐normal skin ICG ratio which is easily understandable.…”

Comparison of Detection of Superior Gluteal Artery Perforator by Indocyanine Green Fluorescence Near-Infrared ANGIOGRAPHY and Handheld Acoustic Doppler Sonography for Reconstruction of Sacral Pressure Injury

“…Detection techniques with P-CTA and magnetic resonance angiography are expensive and require radiation exposure. A combined examination is economically superior because ADS is free and ICG fluorescent angiography only costs the price of the ICG dye [9].…”

Usefulness of a finger-mounted tissue oximeter with near-infrared spectroscopy for evaluating the intestinal oxygenation and viability in rats

“…Currently, intestinal ischemia is evaluated by ICG and Doppler ultrasound, but these methods are associated with problems such as complexity, quantitativity, and repeatability, and no standard method has been established [4,[21][22][23]. The finger-mounted tissue oximeter used in this study is a simple and quantitative tissue oxygen saturation monitoring device that uses NIRS technology.…”

“…NIRS was first reported in the 1980s and it has been used primarily to assess cerebral circulation [ 23 ]. Previous NIRS measuring devices were used to evaluate adults’ cerebral blood flow to a depth of 1–3 cm [ 9 , 24 , 25 ], but these devices are unsuitable for assessing intestinal tissue.…”