Operations on the sensory root (Frazier’s operation).
Charles Frazier advocates the ‘physiologic extirpation’ of the sensory root of the ganglion. The advantages claimed over other methods are as follows:—
1. Control of hæmorrhage and avoidance of risk of injury to the cavernous sinus. The ganglion receives its main blood-supply from below. Division of the sensory root leaves the base of the ganglion undisturbed, and this cause of free bleeding is removed. With respect to the cavernous sinus, the operation is confined to the root of the ganglion and consequently the sinus is in no wise concerned.
2. Simple technique. The operation of division of the sensory root is complete before the difficulties common to extraction of the ganglion have commenced.
3. Avoidance of injury to adjacent structures. The cavernous sinus is not touched; the sixth nerve, which is intimately related to the ophthalmic branch, is not exposed; and the motor-fibres which, passing beneath the ganglion, join the third division outside the skull, and which are almost necessarily injured in the ganglionic operation, may, in division of the sensory root, escape implication.
4. Reduction in the rate of mortality. The operation is said to be more economical of time, to entail less hæmorrhage, and therefore to be less dangerous.
5. Absence of ocular changes. After division of the sensory root ocular changes are absent, due in part to the fact that the ocular nerves are left intact, and also to the probability that ‘sympathetic fibres pass to the eye after entering the trigeminal nerve through the Gasserian ganglion’ (Spiller).
In the consideration of these advantages it should be noted that they are mainly directed against procedures in which complete extirpation of the ganglion is attempted, and are of less weight when contrasted with the partial excision advocated by Hutchinson.
Frazier’s operation[76] on the sensory root.
‘A horse-shoe shaped incision is made, beginning at the middle of the zygoma and terminating a little below the apex of the lobe of the ear (see [Fig. 91]). The musculo-cutaneous flap is made purposely a little larger than the opening in the skull. An opening is made in the skull with a diameter not exceeding 3 cm. and extending down as far as the infra-temporal crest. The dura is separated from the base of the skull with a blunt retractor as far as the foramen spinosum. The middle meningeal artery is ligatured and the dura mater incised directly over the third division at the margin of the foramen ovale and separated from the upper surface of the ganglion as far back as the sensory root. The latter is picked up with a blunt hook, grasped with forceps and divided or avulsed. It is necessary only to expose the posterior portion of the ganglion; the second and third divisions of the fifth, the structures on the inner side of the ganglion, and the cavernous sinus, are left undisturbed.’