Objectives: To report a rare presentation of dehiscent infraorbital canal associated with a maxillary antral cyst.

Case report: A 26-year-old woman presented with symptoms of right infraorbital nerve dysfunction experienced while travelling by aeroplane. She was subsequently diagnosed with dehiscent infraorbital canal and large maxillary antral cyst on computed tomography scanning. The cyst was removed by endoscopic sinus surgery, and the patient's symptoms resolved.

Discussion: The effects of barotrauma on the ears and paranasal sinuses are reviewed. This is the first report of infraorbital nerve dysfunction caused by altered atmospheric pressure in the presence of dehiscent infraorbital canal and maxillary antral cyst. Endoscopic sinus surgery was successful in relieving the symptoms in this case.

Objective: Trigeminal neuromas are rare tumours that may involve any part of the Vth nerve complex, including extracranial peripheral divisions of the nerve. A series of eight patients with intracranial trigeminal neuromas who underwent surgical management are presented.

Methods: The hospital records and radiological images were reviewed with regard to clinical presentation, surgical approach, operative findings, peri-operative morbidity and neurological outcome, and percentage of tumour recurrence.

Results: The principal presenting symptoms were those of involvement of the trigeminal nerve with sensory impairment in one or more of the three divisions. Tumour location was the prime determinant of surgical approach. Lateral skull base approaches were used as they are considered to be superior for identifying tumour origin, extension, and relationship to surrounding structures. Total excision of the tumour was carried out in three of the eight patients. In the remaining five patients some tumour was left purposely in order to minimize neurological deficit and optimize post-operative quality of life. There was no peri-operative mortality or major morbidity in our series. Five patients experienced symptomatic tumour recurrence and revision surgery was performed.

Conclusion: Management of trigeminal neuromas is complex and requires a multidisciplinary approach. Pre-operative surgical planning allows tumour removal with preservation of important neural structures in the majority of cases. For large tumours occupying both the middle and posterior cranial fossae, the retrosigmoid/retrolabyrinthine/middle cranial fossa approach provides good exposure and results in minimal brain retraction. A Fisch type C approach is necessary for the largest tumours. Long-term follow up with interval imaging is mandatory to exclude long-term tumour recurrence.

The cuffed oropharyngeal airway is a modified Guedel airway and is recommended for anaesthesia in spontaneously breathing patients. To our knowledge this is the first report of transient unilateral lingual nerve palsy after the use of a cuffed oropharyngeal airway to maintain anaesthesia during arthroscopy of an ankle. The aetiology of lingual nerve damage is multi-factorial. The possible mechanisms involved include anterior displacement of the mandible during insertion of the cuffed oropharyngeal airway (as in the jaw hrust manoeuvre), compression of the nerve against the mandible, or stretching of the nerve over the hyoglossus by the cuff of the cuffed oropharyngeal airway. We recommend gentle airway manipulation with the use of the cuffed oropharyngeal airway, avoidance of excessive cuff inflation and early recognition of such a complication if it occurs.

We describe a patient with trigeminal neunnoma whose main presenting symptom was trismus. This has not previously been reported in the literature. We review the previously described symptoms and signs of trigeminal neurinoma.

An understanding of migraine must be based on data concerning the anatomy and physiology of the pain-sensitive intracranial structures. Stimulation of the superior sagittal sinus produces changes in brain blood flow and changes in neuropeptide levels similar to those seen in humans during migraine. To better understand the anatomy of the central ramifications of pain-sensitive intracranial structures we have examined the distribution of c-fos immunoreactivity in the monkey when the sinus is stimulated. Six adult Macaca nemestrina monkeys were anaesthetised. The superior sagittal sinus was isolated after a midline craniotomy and a paraffin well created. At 24 h after completion of the surgery the sinus was stimulated electrically for 1 h and the brain subsequently removed and processed for c-fos. In control animals in which the sinus was isolated but not stimulated there was a small amount of c-fos expression in the caudal brainstem and upper cervical spinal cord. Stimulation of the superior sagittal sinus evoked expression of c-fos in the caudal superfical laminae of the trigeminal nucleus and in superficial laminae of the dorsal horn of the C1 level of the upper cervical spinal cord. A lesser amount of c-fos was seen at C2 while no significant labelling above control was observed at C3. These data, while largely confirming the results from the cat concerning the central distribution trigeminovascular afferents, underscore a possibly unique specialisation of trigeminovascular afferents at the C1 level. Given the close evolutionary relationship of the monkey to man it is likely that the cells described in this study represent for primates the nucleus that mediates the pain of migraine.

Tumours at the skull base may show perineural infiltration of the mandibular nerve. Subsequent retrograde spread into the cavernous sinus, Gasserian ganglion, the trigeminal nerve and the pons may be seen. The patient, a known and treated case of nasopharyngeal carcinoma (NPC), complained of trigeminal neuralgia and difficulty in chewing. Magnetic resonance imaging (MRI) revealed a Gasserian ganglion and trigeminal infiltration with resultant atrophy of the muscles innervated by the mandibular nerve. Proximal cranial nerve involvement should be suspected in patients with skull base malignancy presenting with trigeminal neuralgia. MRI is the modality of choice in delineating the pathological process.

A case of neurapraxia of the infraorbital nerve occurring as a result of maxillary sinus barotrauma in a diver is presented. Existing reports of a similar nature are reviewed and the pathogenesis of cranial nerve involvement in barotrauma is discussed. Guidelines for treatment are suggested.