Laser-Doppler flowmetry and Horner's syndrome in patients with complete unilateral damage to the parasellar sympathetic fibers during cavernous sinus surgery

Aim

To determine ocular, sudomotor, and vasomotor components of Horner’s syndrome resulting from complete unilateral intraoperative damage to the parasellar sympathetic fibers during cavernous sinus surgery.

Methods

Complete damage to the parasellar sympathetic fibers was found in four patients operated for central skull base lesions. Pupilometry, eyelid fissure measurement, Hertel’s exophthalmometry, starch iodine sweat test, and laser-Doppler perfusion assessment of bilaterally symmetrical forehead and cheek areas were performed.

Results

Pupil diameter was smaller and the eyelid fissure was >2 mm narrower on the affected side in all four patients. Exophthalmometry after the operation never revealed >1 mm difference. Anhydrosis was localized to the medial forehead in three and to the entire forehead in one patient. Average perfusion did not significantly differ between the affected and opposite side of the forehead or cheek.

Conclusions

The parasellar sympathetic fibers exclusively innervate the orbit and variably innervate the forehead sweat glands. No conclusion regarding their contribution to the facial vasomotor control could be established.The anatomical relationships of the cranial nerves III, IV, the first division of the cranial nerve V, and VI, internal carotid artery and its branches, venous compartments and tributaries, and related osseous structures with adjacent dural folds in the cavernous sinus or parasellar space are well described (1,2). The parasellar space contains distinct sympathetic fiber bundles (1,2), which originate from the superior cervical ganglion and travel along the internal and external carotid arteries. Sympathetic fibers around the external carotid artery accompany its branches to supply the majority of the facial blood vessels and sweat glands (3). Sympathetic fibers around the internal carotid artery form the internal carotid nerve, give off caroticotympanic fibers and deep petrosal nerve in the carotid canal, and divide into the larger anterosuperior and smaller posteroinferior group (3-5). Sympathetic fibers inside the parasellar space are distributed systematically rather than in a plexiform arrangement (2,6). Most parasellar sympathetic fibers adhere to the cranial nerve VI, but then leave it usually after a few millimeters to join the first division of the cranial nerve V before entering the superior orbital fissure (5-13).It has been postulated that the parasellar sympathetic fibers innervate the orbit and contribute to the innervation of blood vessels and sweat glands of an as yet unproven forehead area (3,7-11,13), which would be difficult to ascertain morphologically (2). However, evidence of the parasellar sympathetic fiber function might come from clinical observation.Our aim was to contribute to the understanding of the facial sympathetic innervation by analyzing the ocular, vasomotor and sudomotor features of Horner’s syndrome resulting from complete unilateral damage to the parasellar sympathetic fibers due to central skull base surgery in four patients.