Longer duration of ischemia is not related to higher complication rate in free tissue transfer

DALLAS – Prolonged ischemic time for free tissue transfer in head and neck (H&N) reconstruction was not related to intraoperative or postoperative complications, a researcher reported here.

Among patients in the quartile of fastest times – an average of 104 minutes of ischemia time in free flap surgery – the postoperative complication rate was 21.3%, while in the fourth quartile (average time of ischemia 276 minutes), the complication rate was 25% (P= 0.634), reported Osama Hamdi, MD, of the University of Virginia (UVA) School of Medicine in Charlottesville, in a poster at the annual meeting of the American Head and Neck Society.

In the shorter ischemia time period, there was no free flap loss, whereas in the longer ischemia group there were three losses (5% of patients), but the results were not statistically significant (P=0.083), said Hamdi MedPage Today.

Hamdi and colleagues noted in the poster that “microvascular free tissue transfer is the gold standard in the reconstruction of complex head and neck defects, leading to improved esthetic and functional outcomes with higher rates of flap survival greater than 95%.Free tissue harvesting requires a period of ischemia between division of the vascular pedicle at the donor site and anastomosis to the recipient vessels.Once the donor pedicle is divided, the times of ischemia begins and the reconstructive surgeon has the option of proceeding directly to the microvascular anastomosis or performing the flap contouring and insertion first.”

Hamdi explained to MedPage today that “Surgeons do free flaps in two main ways. Either they do the insert first – making sure the flap is in the correct position, then perfusing the flap – while others will do first the anastomosis to ensure that the lack of blood flow does not compromise the flap.There is a conflict of opinion as to how long this period of ischemia may last before there is damage done to the aileron There is a lot of literature on this, but little is consistent.

The authors conducted the retrospective cohort study at a single tertiary care academic medical center in patients (n=249) who underwent free flap reconstruction between August 2014 and April 2021. The mean patient age was 61 years old and almost 71% of the patients were men. In terms of flap type, almost half had a radial forearm free flap (RFFF).

The average duration of ischemia was 182.2 minutes, 57% of patients presenting under this duration. In terms of ischemia time by flap type, they found that the latissimus flap had the shortest mean ischemia time at 158.4 minutes, while the scapula flap had the longest at 251, 5 minutes.

“It is evident that flaps containing only soft tissue (RFFF, ALT [anterolateral thigh]and Latissimus) have a shorter ischemia time (mean 161.2 minutes) compared to bone-containing flaps (mean 254 minutes),” they said.

Hamdi and colleagues reported that patients in the fourth quartile for ischemic times were “significantly more likely to have a history of radiation therapy, malignant indication for surgery, bone defect, bone flap, and plate use, as well than longer interoperative times and length of stay”. [LOS].”

The authors also reported that, based on univariate analysis, there was a significant increase in ischemia time for patients with benign pathology (P=0.004) and those with an ablative defect involving resection of the oral cavity (P=0.011). They also found the harvesting of free flap containing bone and the need to place reconstruction plates. were associated with a significant increase in ischemia time (P

“Our results indicate that ischemia time up to 7.2 hours is well tolerated and has no association with flap survival, postoperative complications, need for revision/revision, or length of hospital stay” , they wrote. “If a longer ischemia time does not compromise the outcome of the flap, the surgeon may spend more time on certain aspects of the reconstruction, including insertion and contouring.”

The authors suggested that “the primary goal of microvascular surgery should be to strive for the best possible reconstructive outcome without placing undue emphasis on ischemic time. Our results should allay some fears of prolonged ischemia , especially for the more novice reconstructive surgeon with inherently longer ischemia and operative times. The most important thing is to get it right.”

Zainab Farzal, MD, MPH, of the University of North Carolina at Chapel Hill, said MedPage todaythat “Usually you do an insert first and when it’s partially in place, you do that anastomosis,” but she acknowledged that “Everyone has their own way of doing things.”

Farzal, who was not involved in the study, called it “somewhat reassuring that we don’t have to look over the clock while we’re doing these procedures, as long as you don’t take a Crazy time to do it.”

  • Ed Susman is a freelance medical writer based in Fort Pierce, Florida, USA.

Disclosures

Hamdi and Farzal did not disclose any relationship with the industry.

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