Obscure Retropharyngeal Mucocutaneous Masses Associated With Acoustic Neurofibromatosis: A Source of Difficult Airway Management
Neurofibromatoses (NF) are a group of autosomal dominant hereditary diseases characterized by formation of tumors from ectodermal and mesodermal tissues. NF type 1 (Von Recklinghausens neurofibromatosis) is the classical neurocutaneous form and NF type 2 (bilateral accoustic neurofibromatosis) is a distinct entity characterized by presence of bilateral schwanommas arising from the vestibular divisions of VIII cranial nerve. Additional association of central nervous system tumors like meningiomas, gliomas (of brain) and ependymomas, astrocytomas (of spinal cord) increase the propensity of such patients to undergo neurosurgical procedures. Intraoral involvement in NF type 1 has been previously reported to complicate airway management1–3; however, similar difficulties in patients with NF type 2 (acoustic neurofibromatosis) has not been previously reported. We encountered such a case and after obtaining written and informed consent, desire to report it.
An 18-year-old man patient with NF type 2 and bilateral vestibular schwanommas was scheduled for left sided retromastoid suboccipital craniotomy and tumor excision. History and routine airway examination during preanesthetic checkup did not reveal any abnormality. After induction, confirmation of mask ventilation and muscle relaxation, conventional laryngoscopy was conducted and tracheal intubation was attempted. During intubation, the presence of 2 discrete lobulated masses arising from the retropharyngeal space obscured the laryngeal view and impeded the successful passage of endotracheal tube into the trachea resulting in intubation failure. As the masses were located deep in the hypopharynx, their presence was missed during the routine preanesthetic airway examination and consequently a scenario of unanticipated difficult airway arose. Reverting back to bag and mask ventilation, a videolaryngoscope (GlideScope GVL) was sought and readied for better visualization. Using the videolaryngoscope, it was possible to visualize the structures better (Fig. 1) and a gum elastic bougie could be negotiated inside the glottic opening. Through the bougie, a 7.5-mm endotracheal tube was railroaded over and the trachea could be intubated. Rest of the surgery proceeded uneventfully.
Because of the relative rarity and recent recognition of NF type 2 (acoustic neurofibromatosis) as a distinct identity, most of the literature concerning anesthetic implications relates to NF type 1.4 Likewise, cases and series describing intraoral involvement, too have preponderance of patients suffering from NF type 1.5 Through this correspondence we would like to alert the neuroanesthesiologists regarding the possibility of coexisting mucocutaneous neurofibromas in obscure intraoral locations in patients with NF type 2 (acoustic neurofibromatosis). In view of their remote locations, these lesions might often be overlooked during routine airway examination and subsequently complicate the airway management. Therefore history taking and airway examination should be meticulous in this subset of patients. Pertinent points like history of dyspnea, stridor, dysphagia, loss or change of voice should warn the neuroanesthesiologists regarding the existence of intraoral growths. Indirect laryngoscopy, fibreoptic examination, and detailed radiologic review should be routinely included in the preanesthetic assessment of these patients to rule out such lesions. Moreover as neurofibromatosis is a progressive disease, the history of previous uneventful anesthetics should not generate complacency1 and presently existing intraoral afflictions should be diligently excluded preoperatively.