Diagnostic accuracy of flexible fiberoptic laryngoscopy: experience from a tertiary health institution in Nigeria

Background Flexible fibreoptic laryngoscopy (FFL) is a technique of laryngeal visualization. The instrument (flexible laryngoscope) is relatively scarce in resource challenged countries. Where available, it is a useful compliment to the armamentarium of clinical tools at the disposal of the otolaryngologist. We evaluated the diagnostic value of flexible fibreoptic laryngoscope in a tertiary health institution in Nigeria. And we hypothesized that its diagnostic precision is comparable to direct laryngoscopy. Methods This is a retrospective study of records of 360 patients referred for FFL at the ENT clinic. Sensitivity and specificity of FFL for laryngeal lesions were determined using direct laryngoscopy (DL) as the gold standard. Results Of the 360 FFL reports studied, 336 additionally underwent DL. FFL findings in 311 (92.6%) cases were comparable with that of DL. FFL had a good detection rate for vocal cord palsy (sensitivity 100%, specificity 80.7%). Pick-up rate for vocal nodules, polyps, papillomatosis and palsy were statistically equal for FFL and DL ( p value = 0.96). Diagnostic accuracy of FFL was good for supraglottic (sensitivity 100%, specificity 88.0%) and glottic (sensitivity 100%, specificity 92.3%) tumours; relatively lower for subglottic (sensitivity 83.3%; specificity 100%) and transglottic (sensitivity 80.0%, specificity 100%) tumours; and least for tumours involving more than on subsites (sensitivity 50%, specificity 100%). Conclusion The sensitivity and specificity of FFL were not the same for all endo-laryngeal lesions; yet, the overall diagnostic accuracy of FFL is comparable with DL. Clinicians should be mindful of this variability to optimize its application.