Why should a surgeon be careful while removing an impacted fish bone in the pyriform
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pyriform fossa anatomy internal laryngeal nerve
The textbooks give a clear and complete answer. Here is a full explanation:
Why Surgeons Must Be Careful Removing an Impacted Fish Bone from the Pyriform Fossa
The Key Anatomical Hazard: The Internal Branch of the Superior Laryngeal Nerve
The most important reason for surgical caution is the intimate relationship between the internal branch of the superior laryngeal nerve (iSLN) and the mucosa of the pyriform fossa (piriform recess).
The internal branch of the superior laryngeal nerve:
- Is a branch of the vagus nerve (CN X)
- Pierces the thyrohyoid membrane and then descends in the medial wall of the pyriform fossa, running directly beneath the mucous membrane - it is essentially submucosal here
- Supplies sensory innervation to: the base of tongue, posterior surface of the epiglottis, aryepiglottic folds, arytenoids, and laryngeal vestibule down to the level of the vocal folds
- Also carries afferent fibres from neuromuscular spindles and stretch receptors in the larynx
Because the nerve travels just under the mucosa of the pyriform fossa's medial wall, any instrumentation - such as forceps used to grasp and extract an impacted fish bone - risks:
- Direct nerve injury - incising, crushing, or stretching the iSLN as it lies submucosal
- Loss of laryngeal sensation - damaging this nerve causes loss of sensation above the vocal folds, impairing the cough reflex and increasing the risk of silent aspiration
- Afferent reflex loss - the nerve carries stretch receptor input; its damage disrupts protective laryngeal reflexes
Additional Hazards in the Pyriform Fossa
| Structure | Risk |
|---|---|
| Internal branch of superior laryngeal nerve (submucosal) | Nerve injury → loss of laryngeal sensation, silent aspiration |
| Thyroid cartilage (lateral wall) | Perforation can cause deep neck infection or surgical emphysema |
| Internal carotid artery and internal jugular vein (lateral) | Vascular injury if the bone has migrated laterally or instrumentation is misdirected |
| Pyriform fossa apex (narrow, blind-ending) | Perforation of the apex leads to the pre-epiglottic/paraglottic space or through to the neck |
| Cricothyroid joint (inferior) | Disruption can affect vocal fold tension |
Clinical Consequence of Nerve Damage
If the iSLN is injured:
- The patient loses protective supraglottic sensation
- Aspiration becomes silent (no cough is triggered when food/liquid enters the larynx)
- This can lead to aspiration pneumonia, which is a serious post-operative complication
In summary: The internal branch of the superior laryngeal nerve runs submucosal along the medial wall of the pyriform fossa and is directly in the operative field. Careless instrumentation while removing an impacted fish bone can transect or contuse it, leading to loss of ipsilateral laryngeal sensation and dangerously impaired airway protective reflexes.
- Scott-Brown's Otorhinolaryngology Head & Neck Surgery - nerve supply of the larynx
- Barash, Cullen & Stoelting's Clinical Anesthesia, 9e - pyriform recess anatomy and superior laryngeal nerve block
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