The Value of Multidetector Row Computed Tomography Angiography for Preoperative Planning of Freestyle Pedicled Perforator Flaps

Preoperative Vascular Imaging in Lower Extremity Free Flap Reconstruction: Comparison Between Imaging Modalities

BACKGROUND

Adequate vascular anatomy and perfusion status are essential for successful lower extremity free tissue transfer. Computed tomography angiography (CTA) is widely available, minimally invasive, and enables visualization of soft tissues and bones. Angiography permits temporal evaluation of flow, identifies potential needs for concurrent endovascular interventions, and enhances visibility in the setting of hardware. Despite widespread availability of these imaging modalities, no standardized algorithm for preoperative imaging prior to lower extremity free flap reconstruction exists.

METHODS

Current Procedural Terminology (CPT) codes identified patients undergoing free flap reconstruction of the lower extremity over an 18-year period (2002-2020). Electronic medical records were reviewed for patient, treatment, and imaging characteristics, and pre- and post-imaging laboratory values. Outcomes included imaging findings and related complications and surgical outcomes.

RESULTS

In total, 405 patients were identified, with 59% (n = 238) undergoing preoperative imaging with angiography, 10% (n = 42) with CTA, 7.2% (n = 29) with both imaging modalities, and 24% (n = 96) with neither performed. Forty percent (122 of 309) of patients who underwent preoperative imaging had less than 3-vessel runoff. Four patients developed contrast-induced nephropathy (CIN) after angiography only and one after having both CTA and angiography. Vessel runoff on CTA and angiography demonstrated moderate correlation.

CONCLUSION

Most patients undergoing lower extremity free tissue transfer underwent preoperative imaging with angiography and/or CTA, 40% of which had less than 3-vessel runoff. Both angiography and CTA had low complication rates, with no statistically significant risk factors identified. Specifically, the incidence of CIN was not found to be significant using either modality. We discuss our institutional algorithm to aid in decision-making for preoperative imaging prior to lower extremity free flap reconstruction. Specifically, we recommend angiography for patients with peripheral vascular disease, internal hardware, or distal defects secondary to trauma.

Concentrated growth factor intradermal injection assisted super-thin flap expansion for repairing skin defects: A randomized, single blinded, split-site study

BACKGROUND

The super-thin skin flap formed by skin and soft tissue expansion has large area and good ductility, so it can be used to repair skin defects. However, because the flap is thin, the blood flow in the dermis of the super-thin expanded flap is weakened, and flap rupture and necrosis after secondary flap transfer may occur.

OBJECTIVE

To compare the skin thickness difference between the expanded ultrathin flaps injected with concentrated growth factor (CGF) and the blank group or saline group.

METHODS

From June 2021 to December 2023, 10 patients (44 sites) with large-area scars or skin tumors were treated, and a single center half randomized controlled trial was conducted. The test site of expander implantation was divided into three groups: intradermal injection of CGF group, normal saline group and blank group. The same amount of expansion was performed every 1-2 weeks, and CGF or normal saline was injected into the dermis every 4 weeks, a total of three times. After 2-3 months of expansion, color Doppler ultrasound was used to measure the skin thickness of each group.

RESULTS

Compared with the blank group, the skin thickness of CGF group was 1.75 ± 0.08 mm, and that of BLA blank group was 1.42 ± 0.07 mm, with statistically significant difference (p < 0.0001); In the other group, compared with the saline group, the skin thickness of the CGF group was 1.54 ± 0.08 mm, and the average skin thickness of the saline group was 1.40 ± 0.08 mm, with significant difference between the two groups (p = 0.0067).

CONCLUSION

CGF intradermal injection can increase the skin thickness of super-thin skin flap in the process of soft tissue expansion, which is a safe and effective auxiliary method of skin expansion.

Clinical Application of Pre-Expanded Perforator Flaps

Background: Challenging large soft tissue defects are typically treated with microvascular free tissue transfer; however, success has been noted with pre-expanded perforator flaps. Objective: To report outcomes and complications from pre-expanded perforator flaps. Methods: A retrospective chart review of patients undergoing tissue reconstruction with pre-expanded perforator flaps between 2014 and 2020. Data collection included flap type, defect characteristics, and complications. Results: All 29 patients had successful flap reconstruction without major complication. The median area of tissue defect was 17 × 13 cm² (range 7 × 4 to 27 × 24 cm²). Mean tissue expansion period was 15.2 weeks (range 9-26 weeks). The most common flap was the pre-expanded internal mammary artery perforator flaps. Conclusion: The findings of this study suggest that combining tissue expansion with a perforator flap for large tissue reconstruction can be successful with limited complications. This technique may allow a larger pliable skin flap that deserves further investigation.

Use of Indocyanine Green Imaging for Perforator Identification in Preexpanded Brachial Artery Perforator Flaps

The tissues of the medial arm as a donor site for perforator flap design have several advantages. However, they are relatively underused with limited reports, partly due to unreliable perforator anatomy. Therefore, we aimed to review our preliminary experience using indocyanine green (ICG) angiography to design and elevate preexpanded pedicled brachial artery perforator (BAP) flaps for regional reconstruction. All patients underwent soft tissue reconstructions using a preexpanded BAP flap in two or three stages. ICG angiography was used to localize perforators during both expander insertion and flap elevation. The pedicle was divided at the third stage 3 weeks following flap elevation for head and neck cases. Sixteen patients underwent reconstructions of the head and neck (n = 13) or shoulder/trunk (n = 3) using 14 perforator-plus and 2 propeller BAP flaps. In total, 50 perforators were identified using ICG imaging, all of which were appreciable during both expander placement and flap elevation. Thirty-five perforators were directly visualized during flap elevation, and an additional 15 perforators were not explored but incorporated into the flap. All flaps survived without necrosis, and the donor sites healed uneventfully without complications. The medial arm provides thin and pliable skin for the resurfacing of regional defects with relatively minimal donor-site morbidity. With the assistance of ICG angiography, perforators of the brachial artery can be reliably identified, facilitating the preexpansion and elevation of pedicled BAP flaps for use in head-neck and trunk reconstruction.

The Impact of Indocyanine-Green Fluorescence Angiography on Intraoperative Decision-Making and Postoperative Outcome in Free Flap Surgery

Background Reliable perfusion of the distal portions of free flaps is decisive for the reconstructive success. Indocyanine green near-infrared video angiography (ICG-NIR-VA) has been adopted for objective assessment of free flap tissue perfusion but is thus far not used on a routine basis. Therefore, we investigated its intraoperative impact on decision-making and postoperative outcome.

Methods From January 2017 to June 2019, 88 consecutive adipo- or fasciocutaneus free flaps were performed in conjunction with intraoperative ICG-NIR-VA. Free flap tissue perfusion was first assessed clinically and then compared with ICG-NIR-VA findings. Based on the results, the decision for intraoperative trimming of critically perfused flap zones was made. The way of decision-making, flap success, and failure rates as well as intra- and postoperative complication rates were analyzed.

Results The overall free flap success rate was 92.0%. Partial flap necrosis occurred in five cases (5.7%) and total flap necrosis in two cases (2.3%). ICG-NIR-VA aided decision-making and flap design in 34 cases (38.6%) and led to complication-free postoperative courses. When ICG-NIR-VA was relied on (82 out of 88 flaps; 93.2%), there was no unpredicted postoperative tissue necrosis (overestimation). When ICG-NIR-VA was not relied on (6 out of 88 flaps; 6.8%), there were five cases of postoperative partial flap necrosis and one case of uneventful healing (underestimation). The sensitivity of ICG-NIR-VA was 100% (95% confidence interval [CI]: 64.6–100) and the specificity was 98.8% (95% CI: 93.3–100) with a positive predictive value of 87.5% (95% CI: 52.9–99.4) and a negative predictive value of 100% (95% CI: 95.4–100).

Conclusion Intraoperative ICG-NIR-VA objectified free flap perfusion and thus refined surgical decision-making on flap design in all cases. It could always predict tissue necrosis and subjectively improved outcomes in free flap surgery at our institution. Furthermore, it could be easily implemented in intraoperative routine, only adding minimal additional operative time.

Future Perspectives of Pre-expanded Perforator Flaps

Although clinical application of a pre-expanded perforator flap is primarily focused on face and neck reconstructions, such a flap has also been used to reconstruct defects in the trunk, extremities, or hands. With better understanding of the improved blood supply to the flap and the mechanism on the prefabrication of blood supply within the flap, the pre-expanded perforator flap will definitely play a more important role in reconstructive surgery and can be used in selected patients by many plastic surgeons worldwide with good reconstructive and cosmetic outcomes.