Thermal Imaging Facilitates Design of a Keystone Perforator Island Flap for a Myxofibrosarcoma Resection Reconstruction: Case Report

Smartphone-based thermography in flap surgery: A systematic review and meta-analysis of perforator identification

Background

Thermography can be used in pre-operative planning of free perforator flap surgeries. Thermography assesses skin temperature by measuring the quantity of infrared radiation observed. In this meta-analysis, authors assess the sensitivity of smartphone-based thermal imaging (SBTI) in the detection of perforators and analyze the difference between static and dynamic imaging.

Materials and methods

Authors followed the PRISMA guidelines for systematic reviews and meta-analyses. The meta package in R was used to conduct the meta-analysis. The "metaprop" function was used to calculate the overall sensitivity estimate and 95% confidence interval. The "metaprop.one" function was used to calculate subgroup estimates for static and dynamic study types. The "metareg" function was used to conduct meta-regression analyses to explore sources of heterogeneity.

Results

This study includes seven articles with 1429 perforators being evaluated. The overall proportion of the sensitivities was estimated to be 0.8754 (95% CI: 0.7542; 0.9414) using a random effects model. The heterogeneity of the studies was high, as indicated by the tau^2 value of 1.2500 (95% CI: 0.4497; 8.4060) and the I^2 value of 92.6% (95% CI: 88.1%; 95.4%). The pooled sensitivity for static imaging was 0.8636 (95%CI: 0.6238-0.9603) with a tau^2 of 2.0661 and a tau of 1.4374, while the pooled sensitivity for dynamic imaging was slightly higher (p = 0.7016) at 0.8993 (95%CI: 0.7412-0.9653) with a smaller tau^2 of 0.8403 and a tau of 0.9167.

Conclusion

Further studies need to confirm that SBTI is a reliable and convenient technique for detecting perforators for the pre-operative planning of free perforator flap surgeries.

Keystone Flap for Closure of Skin Cancer Defects on the Upper Extremity

Background: We sought to examine the efficacy of the Keystone Design Perforator Island Flap (KDPIF) for the reconstruction of skin cancer excision defects isolated to the upper extremity. In particular, to examine the size of defects repaired and the complications associated with the keystone flap procedure isolated to the upper extremity. Methods: This is a retrospective chart review including all patients older than 18 years of age who received a KDPIF procedure between February 2013 and February 2019 for the oncologic reconstruction of skin cancer defects isolated to the upper extremities by a single surgeon. All procedures were done according to the original description by Behan. Results: A total of 32 patients, 18 (56%) male and 14 (44%) female, received 35 keystone flaps between February 2013 and February 2019. The mean age of the males and females was 70.5 and 79.7 years of age, respectively. Thirty-five lesions suspicious for cancer were excised and 14 (40%) basal cell carcinoma (BCC), 11 (31%) squamous cell carcinoma (SCC), 9 (26%) melanoma, and 1 (3%) actinic keratoses diagnoses were histopathologically determined. Skin defect excisions varied from 3.53 cm2 to 31.42 cm2. No intraoperative or postoperative complications occurred. Conclusions: The keystone flap is a successful versatile flap procedure with a low or absent complication rate for the reconstruction of skin cancer excision defects of various locations (eg arm, hand, elbow, forearm, shoulder, and wrist), cancer pathologies, and sizes on the upper extremity. When needed, a Doppler may successfully identify adequate perforating blood vessels for the relatively larger flaps.

The Role of FLIR ONE Thermography in Complex Regional Pain Syndrome: A Case Series

ABSTRACT

Complex regional pain syndrome remains a debated syndrome characterized by symptoms and signs, including pain, sensory disturbances, thermal asymmetry, edema, and motor impairments. Thermography is a tool that assesses skin surface temperature distribution. Current literature focuses on the role of thermography for diagnostic purposes; however, its role in monitoring the response to treatment in complex regional pain syndrome is unclear. We present a case series of four patients with complex regional pain syndrome where a FLIR ONE thermal imaging camera (FLIR Systems, Inc, Wilsonville, OR) was used to assist in the diagnosis of complex regional pain syndrome, capture the effects of diagnostic nerve blocks to evaluate a peripheral nerve contribution to complex regional pain syndrome, as well as monitor and assess treatment efficacy with prednisone and surgery. Four patients were screened by clinical assessment to meet the Budapest Criteria. The thermal images revealed improvement in the temperature distribution after therapeutic intervention. We also noted temporary but immediate changes on thermal imaging with diagnostic nerve blocks. Our cases suggest that the FLIR ONE thermal imaging camera has the potential to be an accessible monitoring tool to assist in diagnosis and assess treatment efficacy in complex regional pain syndrome over time.

High-end versus Low-end Thermal Imaging for Detection of Arterial Perforators

Supplemental Digital Content is available in the text.

Thermal imaging was first reported as a method for detection of arterial perforators in 1968 and has since been shown to be an extremely accurate way to assess perforators with an audible Doppler signal, using high-end professional thermal cameras. This technology has recently become easily accessible with the advent of smartphone-compatible, low-end thermal cameras. Several groups have reported on the use of these devices in the pre-, intra-, and postoperative phase, yet there have been few attempts to validate them against existing methods or compare them with high-end thermal cameras.