2. Academic Validation
  3. Identification of Degenerated Murine Facial Nerves With Fluorescence Labeling After Transection Injury

Identification of Degenerated Murine Facial Nerves With Fluorescence Labeling After Transection Injury

  • Otolaryngol Head Neck Surg. 2023 Aug;169(2):234-242. doi: 10.1002/ohn.262.
Kayva L Crawford 1,  Yu-Jin Lee 2,  Marisa Hom 2,  Eben L Rosenthal 3,  Ryan K Orosco 1 4,  Quyen T Nguyen 1
Affiliations

Affiliations

  • 1 Department of Otolaryngology-Head and Neck Surgery, University of California San Diego, San Diego, California, USA.
  • 2 Department of Otolaryngology-Head and Neck Surgery, Stanford University, Palo Alto, California, USA.
  • 3 Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, USA.
  • 4 Hanna and Mark Gleiberman Head and Neck Cancer Center, Moores Cancer Center, University of California San Diego, California, San Diego, USA.
PMID: 36758958 DOI: 10.1002/ohn.262
Abstract

Objective: Delayed peripheral nerve repair is complicated by nerve degeneration and atrophy that can prevent identification. We use a murine facial nerve transection model to demonstrate the efficacy of ALM-488 (bevonescein) in labeling degenerated facial nerves with quantitative image analysis and qualitative survey data.

Study design: Prospective cohort study.

Setting: Laboratory.

Methods: Ten wild-type mice underwent transection of the lower facial nerve division with subsequent degeneration. Either 9 (n = 5 mice) or 12 (n = 5 mice) weeks later, mice underwent intravenous infusion of ALM-488 with in vivo real-time fluorescence imaging (FL) of the facial nerve. Using ImageJ, the mean gray value of each nerve segment under white LIGHT reflectance (WLR) and FL was compared to that of adjacent soft tissue to calculate the signal-to-background ratio (SBR). A survey was distributed to evaluate the perceived utility of ALM-488 in surgeon identification of degenerated nerves.

Results: The mean SBR of degenerated nerves was 1.08 (standard deviation [SD]: 0.07) under WLR and 2.11 (SD: 0.31) under FL (p < 0.001). In mice with degenerated nerves, survey participants identified on average 3.01 (SD: 1.84) nerve branches under WLR and 5.73 (SD: 1.88) under FL (p < 0.0001). Under FL, 47 of 48 survey responses correctly identified isolated, degenerated nerves; in contrast, only 12 responses identified degenerated nerves under WLR (p < 0.0001).

Conclusion: Preoperative intravenous infusion of ALM-488 with FL improves the identification of degenerated facial nerves. ALM-488 also improves surgeon confidence in nerve identification, particularly in degenerated nerve branches that are not visible with WLR.

Keywords

facial nerve; facial nerve injury; facial palsy; fluorescence-guided surgery; fluorescent microscopy.

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