Technical Aspects of High-Resolution Color-Coded Duplex Sonography for the Design of Perforator Flaps

Comparative Study of Small Vessel (under 0.8 mm) Anastomosed Free Flap and Larger Vessel (over 0.8 mm) Anastomosed Free Flap: Does Supermicrosurgery Provide Sufficient Blood Flow to the Free Flap?

BACKGROUND

 This study aimed to quantify the blood flow of free flaps and compare the blood flow of small vessel (<0.8 mm) and larger vessel (>0.8 mm) anastomosed free flaps.

METHODS

 This retrospective study included patients treated successfully with a perforator free flap in the lower extremity between June 2015 and March 2017. A color duplex ultrasound system measured the flow volume through the pedicle by analyzing the mean flow peak velocity, flow volume, and flow volume per 100 g of the flap.

RESULTS

 A total of 69 patients were enrolled in this study. There was no statistical difference in peak velocity between the small vessel anastomosed free flap (25.2 ± 5.6) and larger vessel anastomosed free flap (26.5 ± 5.4). Flow volume (6.8 ± 4.2 vs. 6.3 ± 3.6) and flow volume/100 g (3.6 ± 3.9 vs. 6.2 ± 6.9) also did not show significant differences.

CONCLUSION

 Small vessel (<0.8 mm) free flaps showed similar flow velocity and flow volume to larger vessel (>0.8 mm) anastomosed free flaps. Blood flow to the small vessel anastomosed free flap was sufficient despite its small vessel size.

The value of sonographic microvascular imaging in the diagnosis of lipedema

BACKGROUND

Lipedema is a chronic disease marked by symmetric enlargement of painful nodular and fibrotic adipose tissue, predominantly affecting the limbs. Since there is no specific test or biomarker for this condition, years often pass before the diagnosis of lipedema is established for the first time, thereby causing psychosocial distress, including depression, eating disorders, and social isolation. Over the last few years several advanced Doppler-based technologies have been developed to visualize slow flow blood vessels and superficial microvascular architecture undetectable by traditional color Doppler flow imaging (CDFI).

OBJECTIVE

The aim of this study was to evaluate the superficial microvascular anatomy in lipedema patients compared to healthy controls and investigate the clinical significance of the Ultra Micro Angiography (UMA) technology in the diagnosis of lipedema. This new technique may contribute to reduce the diagnostic delay and, eventually, establish and guide treatment strategies toward a better therapeutic outcome in lipedema patients.

METHODS

25 patients with lipedema and ten healthy controls with no history of lipedema were included in this study. All ultrasound examinations were performed on a novel high-performance ultrasound system (Resona R9/Mindray) using CDFI and the UMA technique.

RESULTS

In all of the patients, Ultra Micro Angiography achieved the excellent visualization of microvascular structures, revealing that most lipedema patients showed grade 3 (n = 13) or grade 2 (n = 8) flow. UMA was superior to CDFI for depicting the microvascular structures.

CONCLUSIONS

Here we show that UMA imaging characterizes the subcutaneous microvasculature with an unprecedented accuracy. The method has the advantage of being sensitive to small, slow-flowing vessels. This allows for the assessment of the course of vessels and vascular pathologies in great detail. Thus, UMA as a non-invasive diagnostic method can improve diagnostic accuracy in lipedema.

Application of B-flow imaging and its enhanced mode in perforator mapping

AIM

To explore the value of B-flow (B-mode blood flow) imaging and its enhanced mode in perforator mapping.

MATERIALS AND METHODS

Before surgery, B-flow imaging, enhanced B-flow imaging, colour Doppler flow imaging (CDFI), and contrast-enhanced ultrasound (CEUS) were used to detect the skin-perforating vessels and small vessels in the fat layer of the donor site. Taking the intra-operative results as the reference standard, the diagnostic consistency and efficiency of the four modes were compared. Statistical analysis was performed using the Friedman M-test, Cochran's Q-test, and the Z-test.

RESULTS

Thirty flaps were excised, with 34 skin-perforating vessels and 25 non-skin-perforating vessels, as confirmed during surgery. In order of the number of skin-perforating vessels detected, the results showed that enhanced B-flow imaging detected more vessels than B-flow imaging and CDFI (all p<0.05), CEUS detected more vessels than B-flow imaging and CDFI (all p<0.05), B-flow imaging detected more vessels than CDFI (p<0.05). All four modes had remarkable and satisfactory diagnostic consistency and effectiveness, but B-flow imaging was the best (sensitivity 100%, specificity 92%, Youden index 0.92). In order of the number of small vessels in the fat layer detected, the results showed that enhanced B-flow imaging detected more vessels than CEUS, B-flow imaging, and CDFI (all p<0.05). CEUS detected more vessels than B-flow imaging and CDFI (all p<0.05).

CONCLUSION

B-flow imaging is an alternative method for perforator mapping. Enhanced B-flow imaging can reveal the microcirculation of flaps.

[Application of infrared thermography technique to assist peroneal artery perforator flap in the repair of oral and maxillofacial defects]

Objective

To explore the application value of infrared thermography (IRT) technique assisted peroneal artery perforator flap in repairing oral and maxillofacial defects.

Methods

The clinical data of 20 patients with oral and maxillofacial malignant tumors treated with peroneal artery perforator flap between October 2020 and December 2021 were retrospectively analysed. There were 13 males and 7 females, with an average age of 56.5 years (range, 32-76 years). There were 8 cases of tongue cancer, 5 cases of parotid gland cancer, 4 cases of buccal cancer, and 3 cases of mandibular gingival cancer; and 12 cases of squamous cell carcinoma, 3 cases of adenoid cystic carcinoma, and 5 cases of mucoepidermoid carcinoma. Color Doppler ultrasound (CDU) and IRT technique were performed before operation to locate the peroneal artery perforator and assist in the design of the flap. The sensitivity, specificity, positive predictive value, and negative predictive value of CDU and IRT technique were compared with the actual exploration during operation. The accuracy of CDU and IRT technique in detecting the number of peroneal artery perforator and the most viable perforating points was compared. The patients were followed up regularly to observe the recovery of donor and recipient sites, the occurrence of complications, and the recurrence and metastasis of tumors.

Results

The sensitivity, specificity, positive predictive value, and negative predictive value of peroneal artery perforators detected by IRT technique before operation were 72.22%, 50.00%, 92.86%, and 16.67% respectively, which were higher than those by CDU (64.17%, 33.33%, 84.62%, and 14.29% respectively). Forty-five peroneal artery perforators were found by CDU before operation, and 35 were confirmed during operation, with an accuracy rate of 77.8%; 43 "hot spots" were found by IRT technique, and 32 peroneal artery perforators were confirmed within the "hot spots" range during operation, with an accuracy rate of 74.4%; there was no significant difference between the two methods ( χ²=0.096, P=0.757). The accuracy rates of the most viable perforating points found by CDU and IRT technique were 80.95% (17/21) and 94.74% (18/19), respectively, and there was no significant difference between them ( χ²=0.115, P=0.734). The localization errors of CDU and IRT technique were (5.12±2.10) and (4.23±1.87) mm, respectively, and there was no significant difference between them ( t=1.416, P=0.165). All the perforator flaps survived, and the incisions of donor and recipient sites healed by first intention. All patients were followed up 5-18 months, with an average of 11 months. The skin flap was soft and had good blood supply, and the lower limb scar was concealed and the lower limb had good function. No lower limb swelling, pain, numbness, ankle instability, or other complications occurred, and no tumor recurrence and metastasis were found during the follow-up.

Conclusion

Compared with the CDU, using the IRT technique to assist the preoperative peroneal artery perforator flap design to repair the oral and maxillofacial defects has a high clinical application value.