A Reliable Method For The Postoperative Monitoring Of Buried Deep Inferior Epigastric Artery Perforator (DIEP) Flaps Using Tissue Oximetry By Near-infrared Spectroscopy
Katherine H. Carruthers, M.D.1, Pankaj Tiwari, M.D.2, Ergun Koack, M.D.2.
1West Virginia University, Morgantown, WV, USA, 2Midwest Breast & Aesthetic Surgery, Gahanna, OH, USA.
PURPOSE: The postoperative monitoring of microvascular free flaps after breast reconstruction has become the standard of care. However, in recent years there has been a shift towards nipple-sparing mastectomy (NSM) techniques which often negates the need for exposed cutaneous flap tissues. Although other techniques for the monitoring of buried flaps have been proposed, none have been able to provide the benefits that come with cutaneous monitoring by tissue oximetry via near-infrared spectroscopy (NIRS). Therefore, we herein propose a novel method for monitoring deepithelialized flap tissues deep to the mastectomy skin flaps using NIRS technology. METHODS: A nipple-sparing mastectomy with subsequent deep inferior epigastric artery perforator (DIEP) flap reconstruction was performed. For the purpose of this study, the flap was designed with a small skin island preserved so that a cutaneous NIRS probe could be affixed. Next, a silicone NIRS probe was placed on a deepithelialized portion of the flap under the mastectomy flap and secured using externalized marionette sutures. The readings from this tunneled device were then compared to the control measurements obtained from the cutaneous NIRS monitor. The changes in StO2 were recorded from both devices and the readings from the tunneled probe were compared to the readings from the cutaneous probe using a paired, two-tailed student's T-test. A significant difference was defined as a p< 0.05. RESULTS: During the monitoring period, there were no issues with probe dislodgment or poor contact with the flap, with signal quality consistently averaging greater than 90. Furthermore, probe removal was easily accomplished at bedside. There was no indication of harm to the mastectomy skin flaps by affixing the probe through this tissue and the pocket which contained the probe quickly closed down after the probe was removed, with no subsequent seroma formation. Using the student's T-test as described above, a p-value of 0.995 was calculated indicating no statistically significant difference between the StO2 readings from the cutaneous and the tunneled probes. CONCLUSION: By using this novel method, NIRS technology can reliably be applied to the monitoring of buried free flap tissues. The proposed technique could be applied to a variety of flaps beyond the realm of breast reconstruction and may prove to be particularly useful in the setting of head and neck reconstruction. The results of this study suggest that high quality postoperative flap monitoring is possible without compromising the aesthetic result.
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