The efficacy of the Cook-Swartz implantable Doppler in the detection of free-flap compromise: a systematic review protocol

Complex reconstruction of the clavicle with a prefabricated medial femur condyle chimeric flap including a superficial circumflex iliac artery perforator flap: A case report

The medial femur condyle (MFC) cortico-periosteal flap is a popular flap for bone reconstruction. The use of a chimeric version of this flap with a skin island has been described, but anatomical arterial variation can occur that prevent its harvest. Furthermore, the donor area of the skin paddle has been debated as poor because of the scarring in a visible area and because of the difficulty in obtaining pliable thin skin. We present a fabricated chimeric MFC cortico-periosteal flap joined with a superficial inferior epigastric perforator (SCIP) flap to reconstruct and augment a sclerotic and insufficient small clavicula with the skin paddle acting as a monitor and as a substitute for the overlying skin. A 52-year-old female patient had a history of multiple refractures of the right hypoplastic clavicle with a diameter of 7 mm, resulting in a sclerotic bone with a fibrotic scar. The reconstruction was done in one surgical session using a cortico-periosteal flap from the left medial condyle and a thin SCIP flap from the left groin. The area of the clavicle to be reconstructed was 3 cm, and the direct overlying skin (approximately 6 × 3 cm) was severely scarred and painful. The MFC flap was 5 × 4 cm, while the SCIP flap was 7 × 3.5 cm. The SCIP flap artery was anastomosed on the table end-to-side to the descending genicular (DG) artery of the MFC, and the vein was anastomosed end-to-end to a comitans vein of the DG artery. The flap fully survived after an initial congestion. At 12 months, we observed a satisfactory reconstruction of the clavicle with an enhanced diameter of 12 mm. The patient recovered full function of the shoulder with no pain. Using a fabricated chimeric flap composed of a medial femoral condyle and a superficial circumflex artery perforator flap may be an additional option for tailored reconstruction of complex osteo-cutaneous defect of clavicle.

Role of Infrared Thermography in Planning and Monitoring of Head and Neck Microvascular Flap Reconstruction

Background

Reconstruction using microvascular free flaps has become the standard of care in head and neck cancer surgery, and their success lies in appropriate planning, adequate revascularization, and early detection of flap compromise so that prompt salvage is possible. This study evaluates the role of infrared thermography in the planning, execution, and postoperative monitoring of microvascular flaps in head and neck reconstructions.

Methods

This is a single institutional, prospective observational study conducted at a tertiary care hospital in South India for 13 months. Twenty patients were included, and their thermographic images were captured in the preoperative, intraoperative, and postoperative settings using the infrared camera FLIR T400. These images were analyzed along with the Doppler, and clinical monitoring findings in all the settings and the temperature difference were calculated postoperatively.

Results

Hotspot perforator marking was made using infrared camera, and perforator marking was made using hand-held Doppler preoperatively, which correlated in 93% of cases. Intraoperatively, flap rewarming was successfully demonstrated in 19 of 20 cases. Postoperatively, flap compromise was observed on infrared thermography during the first 24 hours but not on clinical monitoring in three cases. The temperature difference values recorded were 5.4°C, 2.4°C, and 4.9°C. The mean of temperature difference of the healthy flaps was 1.0°C (range 0.1°C-1.8°C).

Conclusion

Infrared thermography provides simple and reliable imaging, which can be used in perforator marking and flap designing preoperatively and checking the flap perfusion and vascular anastomosis patency intra- and postoperatively.

Clinical and Radiological Safety of Retained Implantable Doppler Devices Used for Free Flap Monitoring

INTRODUCTION

Implantable Doppler devices are reliable adjuncts used for free flap monitoring. Occasionally, the probe/wire is not removed and remains in the soft tissues. The clinical safety of the retained probes and safety and compatibility with magnetic resonance imaging (MRI) have not been studied. We present a series of retained implantable Doppler probes examining clinic outcomes, safety and compatibility with MRI, and effect on MRI image quality.

METHODS

A retrospective review was conducted of patients who had an implantable Doppler device for free flap monitoring between July 2007 and August 2018. Routine post-operative imaging was reviewed for all patients to identify incidental findings of a retained probe. A subset of patients with retained implantable Doppler probes who underwent MRI was identified. Magnetic resonance images were reviewed to detect any degradation of image quality.

RESULTS

A total of 323 patients who had an implantable Doppler device placed were reviewed 18 (5.6%) patients were identified with a retained probe and were included in this study. Mean age was 49 years with mean follow-up of 34.4 months. One potential device-related complication occurred in 1 (5.6%) patient. A total of 32 MRI scans were performed in 8 patients with retained devices, including 6 patients who underwent a total of 21 MRIs of the surgical site. There were no complications related to the MRI scans, and we found no significant degradation of image quality.

CONCLUSION

Retained implantable Doppler probes were not associated with substantial adverse clinical outcomes nor affected MRI image quality of the surgical site.

Measuring Flap Oxygen Using Electron Paramagnetic Resonance Oximetry

OBJECTIVES/HYPOTHESIS

To determine if electron paramagnetic resonance (EPR) oximetry is a viable technology to aid in flap monitoring.

STUDY DESIGN

Prospective cohort.

METHODS

This was a cohort study assessing accuracy and speed of EPR oximetry in detecting ischemia of a saphenous artery-based flap in a rat model, using transcutaneous oximetry as a control. Measurements were obtained under both resting and ischemic conditions for nine Sprague Dawley rats (18 flaps), for 3 postoperative days following flap elevation.

RESULTS

The mean partial pressure of oxygen prior to tourniquet application was 66.9 ± 8.9 mm Hg with EPR oximetry and 64.7 ± 5.2 mm Hg with transcutaneous oximetry (P = .45). Mean partial pressures of oxygen during tourniquet application were 8.9 ± 3.2 mm Hg and 8.5 ± 2.9 mm Hg for EPR oximetry and transcutaneous oximetry, respectively (P = .48), and 67.2 ± 6.9 mm Hg and 65.3 ± 6.1 mm Hg after tourniquet release for EPR oximetry and transcutaneous oximetry, respectively (P = .44). The mean ischemia detection time of EPR oximetry was 49 ± 21 seconds.

CONCLUSIONS

Offering timely, accurate, and noninvasive tissue oxygen measurements, EPR oximetry is a promising adjunct in flap monitoring.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:E415-E419, 2019.

Implantable Doppler monitoring of buried free flaps during vascularized lymph node transfer

BACKGROUND AND OBJECTIVES

Reliable flap monitoring is crucial to the success of free tissue transfer, including vascularized lymph node transfer (VLNT). However, no large-scale study has examined implantable Doppler monitoring in VLNT. We aimed to determine whether an implantable Doppler system can reliably monitor flap perfusion during VLNT and also to calculate the sensitivity and specificity of this system for detecting compromise in the monitored vessel.

METHODS

An analysis of prospectively collected data of patients who underwent buried VLNT with implantable Doppler monitoring between 2014 and 2015 was performed.

RESULTS

A consecutive series of 100 patients underwent VLNT with implantable Doppler monitoring. Five cases required return to the operating room for flap exploration due to a change in Doppler signal quality. All compromised flaps were salvaged. The sensitivity of the implantable Doppler system for flap monitoring was 100%, the specificity was 97.9%, the positive predictive value was 60%, and the negative predictive value was 100%. The false-positive rate was 2%.

CONCLUSIONS

This is the largest reported series of implantable Doppler monitoring of free flap perfusion during VLNT. Our experience suggests that this is a safe and effective technique for postoperative monitoring of VLNT.