Monitoring Vascular Compromise Using Ultrasound After Free Tissue Transfer

Ultrasound in Microsurgery: Current Applications and New Frontiers

Ultrasound has revolutionized reconstructive microsurgery, offering real-time imaging and enhanced precision allowing for preoperative flap planning, recipient vessel identification and selection, postoperative flap monitoring, and lymphatic surgery. This narrative review of the literature provides an updated evidence-based overlook on the current applications and emerging frontiers of ultrasound in microsurgery, focusing on free tissue transfer and lymphatic surgery. Color duplex ultrasound (CDU) plays a pivotal role in preoperative flap planning and design, providing real-time imaging that enables detailed perforator mapping, perforator suitability assessment, blood flow velocity measurement, and, ultimately, flap design optimization. Ultrasound also aids in recipient vessel selection by providing assessment of caliber, patency, location, and flow velocity of recipient vessels. Postoperatively, ultrasound enables real-time monitoring of flap perfusion, providing early detection of potential flap compromise and improved flap survival rates. In lymphatic surgery, ultra-high frequency ultrasound (UHFUS) offers precise mapping and evaluation of lymphatic vessels, improving efficacy and efficiency by targeting larger dilated vessels. Integrating ultrasound into reconstructive microsurgery represents a significant advancement in the utilization of imaging in the field. With growing accessibility of devices, improved training, and technological advancements, using ultrasound as a key imaging tool offers substantial potential for the evolution of reconstructive microsurgery.

Real-Time Assessment of Free Flap Capillary Circulation Using Videocapillaroscopy

BACKGROUND

Free tissue transfer is a common method of reconstruction for various surgical defects. Many clinical assessment methods, including flap color monitoring and capillary refill time measurements, are commonly used to assess the microcirculation of the flap, yet there is no objective tool available that can clear real-time visualization of the flap microcirculation. The purpose of this study was to use a novel videocapillaroscope to evaluate the circulation changes on free flap skin surfaces while purposely clamping pedicle vessels.

METHODS

Ten patients who underwent free flap transfer for head and neck cancer from November of 2019 to June of 2020 were included in the study. Videocapillaroscopic observation was performed after flap elevation, and changes in the flap skin capillary circulation with artery-controlled and vein-controlled clamping were recorded.

RESULTS

Average total surgery time was 517.91 minutes (SD, 73.3 minutes), average flap elevation time was 102.9 minutes (SD, 18.3 minutes). When the pedicle artery or vein was purposely clamped, the movement of red blood cells in blood vessels stopped; when clamps were removed after 60 seconds, the restoration of red blood cell movements was rapidly observed. When the pedicle artery was clamped, the number of visualizable blood vessels decreased and flap color became relatively white. When the pedicle vein was clamped, the number of visualizable blood vessels increased, and flap color tone had a tendency toward red.

CONCLUSION

Novel videocapillaroscopy can be utilized for objective real-time flap monitoring by directly visualizing flap skin capillary microcirculation.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Applications of Ultrasound in the Postoperative Period: A Review

Background Recent advances in ultrasound technology have further increased its potential for routine use by plastic and reconstructive surgeons.

Methods An extensive literature review was performed to determine the most common applications of ultrasound in the postoperative care of plastic and reconstructive surgery patients.

Results In contrast with other available imaging modalities, ultrasound is cost-effective, rapid to obtain, eliminates the need for ionizing radiation or intravenous contrast, and has virtually no contraindications. In addition to its diagnostic capabilities, ultrasound can also be used to facilitate treatment of common postoperative concerns conveniently at the bedside or in an office setting.

Conclusion This article presents a review of the current applications of ultrasound imaging in the postoperative care of plastic and reconstructive surgery patients, including free flap monitoring following microsurgery, diagnosis and treatment of hematoma and seroma, including those associated with BIA-ALCL, and breast implant surveillance.

Repair of Compound Dorsal Defects of the Digits Using a Free Antegrade Palmaris Longus Tendocutaneous Venous Flap

PURPOSE

To investigate the clinical effect of repairing small dorsal digit compound tissue defects using a free palmaris longus tendocutaneous flap nourished by venous blood.

METHODS

In a retrospective analysis of patients treated between March 2010 and October 2017, 18 patients were identified as having small compound tissue defects, which were repaired using a free palmaris longus tendocutaneous flap nourished by venous blood. The average age of the patients, including 15 male and 3 female patients, was 34 years (range, 22-55 years). The mean wound size was 6 cm² (range, 2.0 × 1.5 to 3.5 × 2.0 cm²). All the patients had dorsal defects. The average length of extensor tendon defect was 2.0 cm (range, 1.0-3.0 cm). The mean area of the flap was 7 cm² (range, 2.5 × 2.0 to 4.0 × 3.5 cm²). The donor sites were primarily closed.

RESULTS

All 18 flaps survived. A vascular crisis due to a venospasm occurred within 48 hours in 3 flaps, but ultimately, all the flaps survived. The patients were followed-up for a mean period of 10 months (range, 3-15 months). All the patients returned to their previous work after 10-12 weeks. No pain or scar contracture was reported in either the recipient or donor site.

CONCLUSIONS

The free antegrade palmaris longus tendocutaneous venous flap enabled the repair of compound tissue defects of the dorsal digit, resulting in acceptable aesthetics, repaired tendon defects, and wound coverage. This surgical method is an option for the reconstruction of small compound defects of digits with extensor defects.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Photoacoustic Microscopy Provides Early Prediction of Tissue Necrosis in Skin Avulsion Injuries

BACKGROUND

Skin avulsion injuries caused by high-energy traffic and machinery accidents are important topics in the field of repair and reconstruction. The injury generates a skin flap with uncertain vascular basis resulting in ischemic necrosis of the distal portion of the flap. Yet there is lack of reliable way for estimating the extent of blood supply in damaged tissue, which has limited the possibility of prompt surgical intervention. Recent studies have confirmed that photoacoustic microscopy imaging has a wide range of applications in the biomedical field owing to its good performance in angiography.

METHODS

In our study, we successfully surgically induced skin avulsion injury on mice hindlimbs. Then, we used this novel approach to image skin microcirculation and predict skin necrosis with impaired blood supply after injury in live mice.

RESULTS AND CONCLUSION

All skin tissues in the avulsed hindlimb flap group show different levels of necrosis at the end of the observation period. The "dark zone" with impaired microcirculation in PAM images, which continuously extends over time, was seen as a prediction of necrosis of skin tissue and at 60 min after surgery was similar to the area of clinical necrosis on postoperative day 7. All these indicate that photoacoustic microscopy imaging is a feasible, precise, high-resolution, non-invasive technique for early prediction of necrosis in skin avulsion injury, providing a promising tool for surgeons to manage the injury.