DEMOGRAPHIC PREDICTORS OF FREE FLAP DAMAGE: SHOULD WE CARE ABOUT THE BODY MASS INDEX?

BACKGROUND

Microvascular free flap surgery is the main technique to head and neck cancer reconstruction, improving survival and functional outcomes.1 Anaesthesiologists have a central role as perioperative physicians to these patients. However, free flap losses still occur at rates between 1-5%.1,2 Some risk factors have been known to contribute to this outcome. We aimed to identify predictors of flap damage.

MATERIALS AND METHODS

We conducted a retrospective case-control study of patients submitted to head and neck free flap surgery from January 2015-April 2017 at Instituto Português de Oncologia de Lisboa Francisco Gentil.
The primary endpoint was flap damage: a composite of flap loss, wound infection and 30-day re-intervention.
Statistical analysis used SPSS 23, IBM. =0,05 was assumed to be statistical significant.

RESULTS AND DISCUSSION

Our study enrolled 87 patients and a detailed data collection was made.
Flap damage was present in 18,6% (n=16) and flap loss in 2,3% patients (n=2). These results are comparable to other series3.
When comparing patients with and without flap damage, Body Mass Index (BMI) was significantly different. Patients with flap damage had a median BMI of 20,56 [IQ 25-75: 18,37-22,38] which compared to 22,03 [IQ: 25-75: 20,13-25,15] in patients without flap damage. A ROC curve was analysed (graph 1) and BMI had a significant discriminatory power for predicting flap damage (AUC 0,67 CI:0,54-0,81). With a cut-off BMI value of 21, lower BMI patients were at significantly increased risk for flap damage (OR 3,96; CI: 1,24- 12,69). The burden of poor nutritional status is associated to postoperative infection rate, immune function and tissue healing,2 all of which contribute to flap damage. BMI should be considered during patient selection. Attempts should be made to optimize patients from a nutritional point of view during the perioperative period. Rehabilitation before cancer surgery as well as embracing the patient since the surgical decision until the postoperative period may be the future to better outcomes.

CONCLUSION

A lower BMI was associated to flap damage. Nutritional status should be promptly assessed and optimized during the perioperative period. Our study could be a background for further work, ultimately to improve patient care.

References
1. 	Gooneratne H, et al. Acta Anaesthesiol Scand. 2013;57(10):1293-1300.
2. 	Leoncini E, et al. Head Neck. 2014;36(10):1391. 
3. 	Haughey BH, et al. Otolaryngol - Head Neck Surg. 2001;125(1):10-17.

03 / Demographic predictors of free flap damage: should we care about the body mass index?