Imaging for thinned perforator flap harvest: current status and future perspectives

Advancing DIEP Flap Monitoring with Optical Imaging Techniques: A Narrative Review

OBJECTIVES

This review aims to explore recent advancements in optical imaging techniques for monitoring the viability of Deep Inferior Epigastric Perforator (DIEP) flap reconstruction. The objectives include highlighting the principles, applications, and clinical utility of optical imaging modalities such as near-infrared spectroscopy (NIRS), indocyanine green (ICG) fluorescence angiography, laser speckle contrast imaging (LSCI), hyperspectral imaging (HSI), dynamic infrared thermography (DIRT), and short-wave infrared thermography (SWIR) in assessing tissue perfusion and oxygenation. Additionally, this review aims to discuss the potential of these techniques in enhancing surgical outcomes by enabling timely intervention in cases of compromised flap perfusion.

MATERIALS AND METHODS

A comprehensive literature review was conducted to identify studies focusing on optical imaging techniques for monitoring DIEP flap viability. We searched PubMed, MEDLINE, and relevant databases, including Google Scholar, Web of Science, Scopus, PsycINFO, IEEE Xplore, and ProQuest Dissertations & Theses, among others, using specific keywords related to optical imaging, DIEP flap reconstruction, tissue perfusion, and surgical outcomes. This extensive search ensured we gathered comprehensive data for our analysis. Articles discussing the principles, applications, and clinical use of NIRS, ICG fluorescence angiography, LSCI, HSI, DIRT, and SWIR in DIEP flap monitoring were selected for inclusion. Data regarding the techniques' effectiveness, advantages, limitations, and potential impact on surgical decision-making were extracted and synthesized.

RESULTS

Optical imaging modalities, including NIRS, ICG fluorescence angiography, LSCI, HSI, DIRT, and SWIR offer a non- or minimal-invasive, real-time assessment of tissue perfusion and oxygenation in DIEP flap reconstruction. These techniques provide objective and quantitative data, enabling surgeons to monitor flap viability accurately. Studies have demonstrated the effectiveness of optical imaging in detecting compromised perfusion and facilitating timely intervention, thereby reducing the risk of flap complications such as partial or total loss. Furthermore, optical imaging modalities have shown promise in improving surgical outcomes by guiding intraoperative decision-making and optimizing patient care.

CONCLUSIONS

Recent advancements in optical imaging techniques present valuable tools for monitoring the viability of DIEP flap reconstruction. NIRS, ICG fluorescence angiography, LSCI, HSI, DIRT, and SWIR offer a non- or minimal-invasive, real-time assessment of tissue perfusion and oxygenation, enabling accurate evaluation of flap viability. These modalities have the potential to enhance surgical outcomes by facilitating timely intervention in cases of compromised perfusion, thereby reducing the risk of flap complications. Incorporating optical imaging into clinical practice can provide surgeons with objective and quantitative data, assisting in informed decision-making for optimal patient care in DIEP flap reconstruction surgeries.

Application of supraclavicular island flap in oral and maxillofacial reconstruction

Several surgical modalities are available for maxillofacial reconstruction as locoregional or microvascular free flaps.

PURPOSE

(a) Evaluate the reliability of the supraclavicular flap in cervico-orofacial region; (b) investigate the role of computed tomography angiography (CTA) in predicting the post-operative viability of the flap; (c) assess the speech, feeding, and esthetics after reconstruction using this flap.

METHODS

Eleven patients included in this study underwent either conventional or delayed harvesting of the supraclavicular flap (SCF). All the patients had diagnostic computed tomography angiography (CTA) of the supraclavicular flap before the surgery.

RESULTS

The mean harvesting time of the flap was 45.45 ± 4.16 min. The average length of the flap was 22.64 ± 1.12 cm, whereas the mean width of the flap was 6.14 ± 1.14 cm. The flap survived in 9 patients, while two patients had complete flap loss. After the surgery, three patients complained of speech difficulties. Two patients had swallowing problems. After the surgery, three patients complained of speech difficulties. Two patients had swallowing problems. Only two patients complained of weakness in the donor site. None of the patients reported that the weakness or pain at the donor site affected their daily activities or quality of life.

CONCLUSION

The pedicled SCF represents a safe and feasible option that can be used to reconstruct a wide array of maxillofacial oncologic defects. However, a study with a larger sample size is recommended to achieve more reliable clinical results for the modified delayed technique modification in terms of their effect on the survival of the supraclavicular flap.

Perforating cutaneous vessels: A key feature of acupoints - Anatomical evidence from five-Shu acupoints in the upper limbs

Acupuncture has been proven an effective clinical treatment for numerous pathological conditions and malfunctions. However, substantial anatomical evidence for acupuncture points (APs) and meridians is still lacking, so the location of APs is relatively subjective and understanding of the biological mechanisms of acupuncture is limited. All these problems hinder the clinical applications and worldwide acceptance of acupuncture. Our long-term microsurgery experience has indicated that Perforating Cutaneous Vessels (PCVs) are highly relevant to APs but the anatomical evidence is insufficient. To address this lack, two specimens of fresh adult human upper limbs were dissected using an advanced vascular perfusion-fixation method and then examined. The results show that all 30 five-Shu APs in the upper limbs have corresponding PCVs. Both specimens showed a 100% coincidence rate between APs and PCVs, indicating that PCVs could be critical anatomical features of APs. This study also provides an anatomical basis for locating APs objectively via preliminary detection of PCVs. The findings could lead to a better theoretical understanding of mechanisms of acupuncture and the essence of meridians.

Pinocembrin alleviates pyroptosis and apoptosis through ROS elimination in random skin flaps via activation of SIRT3

Random skin flap grafting is the most common skin grafting technique in reconstructive surgery. Despite progress in techniques, the incidence of distal flap necrosis still exceeds 3%, which limits its use in clinical practice. Current methods for treating distal flap necrosis are still lacking. Pinocembrin (Pino) can inhibit reactive oxygen species (ROS) and cell death in a variety of diseases, such as cardiovascular diseases, but the role of Pino in random flaps has not been explored. Therefore, we explore how Pino can enhance flap survival and its specific upstream mechanisms via macroscopic examination, Doppler, immunohistochemistry, and western blot. The results suggested that Pino can enhance the viability of random flaps by inhibiting ROS, pyroptosis and apoptosis. The above effects were reversed by co-administration of Pino with adeno-associated virus-silencing information regulator 2 homolog 3 (SIRT3) shRNA, proving the beneficial effect of Pino on the flaps relied on SIRT3. In addition, we also found that Pino up-regulates SIRT3 expression by activating the AMP-activated protein kinase (AMPK) pathway. This study proved that Pino can improve random flap viability by eliminating ROS, and ROS-induced cell death through the activation of SIRT3, which are triggered by the AMPK/PGC-1α signaling pathway.

Precision of Dynamic Infrared Thermography in Anterolateral Thigh Flap Planning: Identification of the Perforator Fascia Passage

Background The anterolateral thigh (ALT) flap is commonly utilized in reconstructive surgery. Preoperative perforator mapping facilitates dissection. Dynamic infrared thermography can be applied to identify ALT perforators. However, its accuracy has not been evaluated in detail before. Therefore, this study aimed to assess the precision of dynamic infrared thermography in ALT perforator localization.

Methods The survey site was defined as a 25 × 8 cm rectangle on the anterolateral thigh and a coordinate system was established. The area was examined consecutively by dynamic infrared thermography with a FLIR ONE camera after 2-minute fan precooling. Two surgeons then independently performed color duplex ultrasound on the basis of the identified hotpots.

Results Twenty-four healthy subjects were examined. About 74.8% of perforators were musculocutaneous or musculoseptocutaneous. The mean distance between study area center and perforator or hotspot center was 51.8 ± 27.3 and 46.5 ± 26.2 mm, respectively. The mean distance from hotspot center to sonographic perforator fascia passage was 15.9 ± 9.9 mm with a maximum of 48.4 mm. The positive predictive value of thermographic ALT perforator identification was 93%.

Conclusion Thermographic hotspot and perforator location diverge widely in ALT flaps. Dynamic infrared thermography can therefore not be used as standalone technique for preoperative ALT perforator identification. However, the application before color duplex ultrasound examination is a reasonable upgrade and can visualize angiosomes and facilitate the examination.

Preoperative perforator localization in anterolateral thigh free flap using acoustic doppler and computed tomography angiography

Objectives

Our aim in this study was to investigate if we could predict perforator localization during ALTF elevation, using information from acoustic Doppler (AD) and computed tomography angiography (CTA).

Methods

Prospective observational data were collected from H&N cancer patients who received reconstruction with ALTF in Ajou University Hospital Cancer Center from June to December, 2021. Total of 21 cases were included in the analysis. Lower extremity angio-CT scans were used to determine the course and depth of the perforator before surgery. During intraoperative design of the ALTF, the possible location of the perforator was identified by AD. After flap elevation, the distance between the actual and Doppler-identified location of the perforator was measured.

Results

The average distance from the actual location to the Doppler-identified location was 1.29 ± 1.26 cm. Among 21 cases, almost all perforators (20 cases) were identified in a circle with a radius equivalent to the depth of the perforator. Perforator depth measured by CTA showed a significant positive correlation with the distance from the actual to Doppler-identified location, regardless of skin thickness or body mass index (BMI).

Conclusions

A circle with a radius equivalent to the CTA-assessed depth of the perforator successfully predicted the location of the perforator in almost all cases. Depth of the perforator measured by CTA combined with Doppler-identified location can help safely locate the perforator during ALTF harvesting.Level of Evidence: 4.