Clinical functional anatomy of the pterygopalatine ganglion, cephalgia and related dysautonomias: A review.

The purpose of this article is to explain the anatomy of the pterygopalatine ganglion (PPG), its location in the pterygopalatine fossa (PPF) in the skull, and the relationship it has to the Vidian nerve terminal branches and the fifth cranial nerve. An overview of the neuro-anatomical/clinical correlations, a spectrum of pathologies affecting the seventh cranial nerve and some therapies both medical and surgical are noted. The focus is the pterygopalatine region with discussion of the proximal courses of the seventh and fifth cranial nerves and their pathological processes. The ganglion is used as an example of neuro-anatomical model for explaining cluster headaches (CH). Radiological correlation is included to clarify the location of the PPF and its clinical importance.

The extended subtemporal transtentorial approach: the impact of trochlear nerve dissection and tentorial incision.

The subtemporal transtentorial approach provides excellent exposure of the incisural space. Incision of the tentorium improves access to the interpeduncular cistern, basilar artery, and rostral ventral pons. Description of the starting and termination points of the tentorial incision has varied greatly. We assessed the impact on surgical exposure of freeing the trochlear nerve (TN) from its dural canal (DC) in addition to dividing and retracting the tentorium. A subtemporal approach was performed on 10 hemispheres of cadaveric specimens. Following exposure of the middle tentorial incisura, the TN is dissected from its DC over a few millimeters. Two retraction sutures are placed along the tentorial edge, posterior to the TN entrance in its DC. The tentorial incision is started between the sutures. Dissection of TN from its DC continues for a short distance. The tentorial incision is extended straight up towards the superior petrosal sinus. Dissection of the TN DC continues anteriorly, up to its entry into the cavernous sinus. The tentorial incision can then be extended, just over the entrance to Meckel's cave, and the flap reflected far anterolateraly. Using this technique, the exposure of the interpeduncular cistern and its content increased by a mean of 8.2 mm (standard deviation [SD] 3.9 mm) in the anteroposterior axis and by 5.5mm (SD 1.9 mm) in the rostrocaudal axis. Tentorial incision following dissection of the TN from its DC optimizes reflection of the tentorium flap anterolateraly, maximizes the exposure, and improves lighting and visibility as well as maneuverability within the interpeduncular and rostral pre-pontine cisterns.