=Modifications of the Hartley-Krause operation.= With the object of obtaining further manipulative room, some surgeons recommend the formation of an osteoplastic flap. This method should never be adopted. It is quite unnecessary, it prolongs the operation, and entails more deformity. Others advise division of the zygoma, both in front and behind, with downward displacement of the intermediate portion. Burghard[75] recommends division and downward displacement of the zygoma together with section of the coronoid process, this process being turned upwards together with its attached temporal muscle. From my own experience, I should regard all these modifications as quite unnecessary, the Hartley-Krause operation permitting an adequate operative field. The deformity resulting from all these more extensive procedures must also be taken into consideration. The lines of incision in the Hartley-Krause operation are more or less concealed by the hairy scalp. [Illustration: FIG. 91. TO ILLUSTRATE THE OPERATIONS FOR EXPOSURE OF THE GASSERIAN GANGLION. _e_, The incision for Frazier’s operation; _f_, The incision for the Hartley-Krause operation (in its most recent modification, the front part of this incision is not carried so far downwards, thus avoiding _b_², that branch of the facial nerve which is distributed to the anterior belly of the occipito-frontalis muscle); _c_, The intra-osseous portion of the anterior division of the middle meningeal artery; _b_¹, The branches of the facial nerve to the orbicularis palpebrarum, &c.] =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.