Surgical Drain Amylase Predicts Salivary Fistula Formation After Head and Neck Free Flap Reconstruction

Monday, September 30, 2024

4:36 PM – 4:42 PM EDT

Location: MBCC, 208

Disclosure(s):

Micah K. Harris, MD:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Kevin J. Contrera, MD, MPH:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Matthew T. Bottegal, BS:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Matthew E. Spector, MD:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Introduction: Salivary fistula after head and neck surgery with free flap reconstruction leads to increased patient morbidity and mortality. The aim of this study was to evaluate whether surgical drain amylase levels predict formation of salivary fistula following head and neck free flap reconstruction.

Methods: Daily postoperative drain fluid amylase was collected on a prospective cohort of patients from 2019 to 2023 who underwent free flap reconstruction. Salivary fistula formation was confirmed by clinical exam, swallow study, or blue dye test.

Results: A total of 80 patients were included (70.4% male, 63.2 ± 11.9 years). Most (85%) had 5 consecutive postoperative days (PODs) collected. Fifteen patients (18.8%) developed salivary fistulas. Fistulas were more common following larynx versus oral cavity surgery (40% vs 13.8%, p = 0.019). Average amylase levels (IU/L) on POD2 (5,006.3 ± 8,138.9 vs 1,787.3 ± 4,387.5, p = 0.035), POD3 (5,801.3 ± 8,190.5 vs 1,559.3 ± 3,958.9, p = 0.004), POD4 (4,977.2 ± 8,276.1 vs 1,725 ± 4977.2, p = 0.045), and POD5 (4,792.4 ± 8,032.3 vs 1,512.7 ± 4,304.2, p < 0.001) were significantly higher in those who developed salivary fistulas versus those who did not. The strongest predictor of fistula versus no fistula was found to be the maximum percent change in amylase concentration between consecutive PODs (Δmax(%)) (+2,850.4% vs +767.5%, p < 0.001). On receiver operating curve (ROC) analysis, an ideal cut-off of +71.8% (sensitivity 86.7%, specificity 63.1%, AUC 0.794) was identified. When controlling for disease subsite and need for postoperative transfusion, a Δmax(%) of +71.8% or greater remained predictive of fistula formation on multivariate logistic regression (OR 11.6, 95%CI 2.1-62.5, p < 0.005). Importantly, among patients who never had an increase in amylase (Δmax(%) < 0), none developed salivary fistulas (sensitivity 100%, negative predictive value 1). Similar results were identified in a subset of only oral cavity patients.

Conclusions: Change in surgical drain amylase concentration is a valuable indicator of postoperative salivary fistula formation following head and neck free flap reconstruction.

Presenting Author(s)

Micah K. Harris, MD

Resident, Department of Otolaryngology
University of Pittsburgh Medical Center
pittsburgh, PA, United States

Disclosure(s):
faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Co-Author(s)

MK

Mark W. Kubik, MD

Department of Otolaryngology - Head and Neck Surgery, University of Pittsburgh School of Medicine, USA

Disclosure information not submitted.
MS

Mario G. Solari, MD

Chief, H&N Reconstruction and Craniofacial Trauma
University of Pittsburgh Medical Center, Department of Plastic Surgery
Pittsburgh, PA, United States

Disclosure information not submitted.
KC

Kevin J. Contrera, MD, MPH

Assistant Professor
Department of Otolaryngology, University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, United States

Disclosure(s):
faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.
Matthew T. Bottegal, BS

Program Coordinator
University of Pittsburgh Medical Center
PITTSBURGH, PA, United States

Disclosure(s):
faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.
MS

Matthew E. Spector, MD

Professor
Department of Otolaryngology, University of Pittsburgh Medical Center
Pittsburgh, PA, United States

Disclosure(s):
faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Senior Author(s)

MS

Matthew E. Spector, MD

Professor
Department of Otolaryngology, University of Pittsburgh Medical Center
Pittsburgh, PA, United States

Disclosure(s):
faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Co-Author(s)

SS

Shaum S. Sridharan, MD

Associate Professor
Department of Otolaryngology, University of Pittsburgh Medical Center
Pittsburgh, PA, United States

Disclosure information not submitted.

Senior Author(s)

SS

Shaum S. Sridharan, MD

Associate Professor
Department of Otolaryngology, University of Pittsburgh Medical Center
Pittsburgh, PA, United States

Disclosure information not submitted.