Absent Uvula: What Mallampati Class?

Sir,

A 50-year-old female presented for pre-anaesthetic check-up for laparoscopic cholecystectomy. The patient had no significant medical or surgical illness and her investigations were within normal limits. Neck movements and mouth opening were normal. On assessment of the oral cavity using the modified Mallampati (MMP) Class, we could not locate the uvula; however, fauces, tonsillar pillars, soft and hard palate were normal and clearly visible [Figure 1]. Patient had a clear speech and did not give any history of frequent respiratory tract infections, snoring, or any airway surgery. The patient was accepted under American Society of Anesthesiologists Class I. The patient was then kept under follow up in view of anticipated co-existence of other airway anomalies. However, no difficulty was encountered perioperatively including airway management.

Figure 1.

Congenital absence of uvula: a

The uvula is a band of connective tissue, glands and small muscle fibres and have been postulated to have a small role in speech, lubrication and central support of the palatopharyngeal arch during swallowing.[1] The causes of absent uvula can be broadly classified into congenital and acquired. The congenital absence of the uvula is very rare in the general population. Jorgenson et al.[2] reported only one case of absent uvula in 2258 oral examinations in neonates. Absent uvula at birth may can be associated with genetic conditions such as cerebrocostomandibular syndrome, anhidrotic ectodermal dysplasia, Apert syndrome and hyperimmunoglobulin E syndrome.[3] These genetic conditions may be associated with factors causing difficulty in airway management as rheumatoid arthritis is associated with anhidrotic ectodermal dysplasia, fusion of cervical vertebra and cleft palate in Alpert syndrome and micrognathia, palate malformations and glossoptosis in hyperimmunoglobulin E syndrome.[2,3] Acquired causes of absent uvula may be secondary to surgery such as uvulopalatopharyngoplasty for obstructive sleep apnoea[4] or cultural practice of removing uvula for chronic cough in Sub-Saharan Africa.[5] As absent uvula is a rare entity, we could not retrieve any case reporting difficult in airway management in these patients.

The MMP classification is widely used for pre-operative assessment of airway.[6] Mallampati Class I: Soft palate, fauces, pillars and uvula; Class II: Soft palate, fauces and uvula; Class III: Soft palate and base of uvula; Class IV: only hard palate visible. In MMP Class I–III, uvula is an important landmark structure on which the classification is based. In the present case, due to the absence of uvula, we experienced an ambiguity while Mallampati classification, but since both tonsillar pillars and fauces were visible, we labelled the patient as MMP Class I.

Absent uvula is a rare entity, and the cause must be explored as it may co-exist with various genetic abnormalities pre-disposing the patient to potential difficult airway. In addition, it also leads to significant ambiguity in airway assessment using MMP classification; thus, emphasis must be laid upon the visualisation of other oropharyngeal structures, especially tonsillar pillars and fauces.

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