乌鸦传媒

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

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

In the period of shorter ischemic times, there were no free flap losses, while in the longer ischemia group, there were three losses (5% of the patients), but the results were not statistically significant (P=0.083), Hamdi told 乌鸦传媒.

Hamdi and colleagues noted in the poster that "Microvascular free tissue transfer is the gold standard in reconstruction of complex head and neck defects, allowing for improved cosmetic and functional outcomes with flap survival rates greater than 95%. Harvest of free tissue requires a period of ischemia between division of the vascular pedicle at the donor site and anastomosis to recipient vessels. Once the donor pedicle is divided, ischemic times begins and the reconstructive surgeon has the option to proceed directly to microvascular anastomosis or perform flap contouring and inset first."

Hamdi explained to 乌鸦传媒 that "Surgeons do free flaps in two major ways. They either do the inset first -- making sure the flap is in the correct position and then perfusing the flap -- while others will do the anastomosis first to make sure that the lack of blood flow doesn't compromise the flap. There is a conflict in opinion as to how long that period of ischemia can last before there is damage done to the flap. 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. Average patient age was 61 and almost 71% of the patients were male. In terms of type of flap, almost half had a radial forearm free flap (RFFF).

The mean ischemic time was 182.2 minutes, with 57% of the patients coming in under that time. In terms of ischemic time by flap type, they found that the latissimus flap had the shortest average ischemic time at 158.4 minutes, while the scapula flap had the longest at 251.5 minutes.

"It is apparent that flaps containing only soft tissue (RFFF, ALT [anterolateral thigh], and Latissimus) have a shorter ischemic time (average 161.2 mins) compared to the bone-containing flaps (average 254 mins)," they stated.

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

The authors also reported that, based on a univariate analysis, there was a significant increase in ischemic time for patients with benign pathology (P=0.004) and those with an ablative defect encompassing resection of oral cavity (P=0.011). They also found that harvest of bone-containing free flap, and the need for placement of reconstructive plates. were tied to significantly increased ischemic time (P<0.001). While the was an association between ischemic time and free flap operating room takebacks and LOS, that significance did not hold on multivariate analysis.

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

The authors suggested that "the main focus of microvascular surgery should be to strive for the best possible reconstructive result 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 ischemic and operative times. The most important thing is to do it right."

Zainab Farzal, MD, MPH, of the University of North Carolina at Chapel Hill, told 乌鸦传媒, that "In general, we do an inset first and when that is partially in place, we 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 out shoulder at the clock while doing these procedures, as long as you don't take a crazy amount of time to do it."

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