Flap warming improves intraoperative indocyanine green angiography (ICGA) assessment of perfusion. An experimental study

BACKGROUND

Indocyanine green angiography (ICGA) is slowly replacing conventional methods of evaluating perfusion during flap surgery. Microcirculatory changes during flap elevation create a marked state of hypoperfusion intraoperatively leading to ICGA underestimation of tissue viability and consequent resection of viable tissue. We propose a novel method of flap warming to induce maximum vasodilation before performing ICGA to increase accuracy in assessing perfusion.

METHODS

Submental flaps harvested on a single perforator were created in 8 pigs. ICG angiography was performed in the intraoperative phase (ICGA-C), after inducing maximum vasodilatation by warming the flap at 42 °C (ICGA-W) and at 24H postoperative (ICGA-24). By setting a fluorescence threshold of 33% as indicative of necrosis, the flap surface deemed viable by ICGA was measured for ICGAC, ICGAW and ICGA24. The results were then compared to the actual flap survival observed clinically at 7 days.

RESULTS

The mean of ICG-C predicted flap survival (FS-C = 49.17%) is 12.97% lower than the mean of actual flap survival on postoperative day 7 (FS = 62.14%). The mean difference between ICG-W and ICG-24 predicted flap survival (FS-W and FS-24) and actual flap survival in the postoperative day 7 (FS) is lower, 3.13% and 2.15%, respectively. Average perfusion recovery over 24 h was 10.83% (FS-24-FS-C).

CONCLUSIONS

Conventional intraoperative ICGA underestimated perfusion in all cases. Warming the flap intraoperatively and achieving maximum vasodilation mitigates the effects of vasoconstriction and mimics the microcirculatory environment encountered at 24 h. Performing angiography after induced vasodilation improves ICGA assessment of flap perfusion.

Incidental papillary thyroid microcarcinoma: is completion surgery required?

BACKGROUND

The indications for completion surgery in patients with thyroid papillary microcarcinoma (PMC), incidentally found in thyroids removed for benign conditions, remains a subject of debate.

METHODS

In a retrospective, transversal, cohort study of 187 incidental PMCs, found during histological examination of the thyroid gland in 2168 patients operated for benign thyroid conditions, we evaluated the influence of initial and completion surgery on pathological features associated to local recurrence and cancer-related mortality.

RESULTS

In the patients with almost total or total thyroidectomy at the first operation, lymphadenectomy of lymph nodes with features suggestive of malignancy on postoperative ultrasound resulted in a statistically significant (p 0.01) increase of node positive patients in pathological examination. Completion surgery in 38 out of 42 patients who underwent less than a total thyroidectomy doesn't result in a significant increase of tumor size, number, multifocality, bilaterality, invasion or nodal metastases. There were no significant differences in postoperative complications between the two groups.

CONCLUSIONS

In patients with less than total thyroidectomy and incidentally found PMC in resection specimens, 1-5 mm in greatest dimension and without extrathyroidal extension, completion surgery was not followed by a significant increase of pathological features associated to cancer related morbidity and mortality.