TREPANNING. 



perfeftly cured. Nofographie Chirurgicale, torn. ii. p. 292. 

 edit. 3. 



Thus we fee that the trepan is often unneceffary in in- 

 juries of the head, with frafture of the (kull, notwithllanding 

 the co-cKiftence of an extravafation between the bone and 

 the dura mater. This doftrine is very different from what 

 is taught in the memoirs of M. Quefnay, in the iirft volume 

 of thofe of the French Academy of Surgery. Default, in 

 the lail years of Ms pradlice, abandoned the operation of 

 the trepan altogether. It has been remarked for many 

 years, that in the Hotel-Dieu this operation has had very 

 little fuccefs ; a circumftance which has excited a fufpicion, 

 that the foul air of the wards of that eftablifhment may have 

 had a (hare in bringing on the unfavourable event. We (hall 

 not here expatiate on the bad effeft of the atmofpheric air 

 on the membranes of the brain ; a thing of which B. Bell 

 feems to have convinced M. Richerand. 



When the (l<ull is fraftured by a blow or fall, and the 

 cafe is a fimple fiffure, the trepan ought to be applied upon 

 the folution of continuity, if the fymptoms indicate a dan- 

 gerous degree of preffure on the brain, and the edges of the 

 fradure are not fufficiently feparated to let the extravafated 

 fluid efcape. 



When the detached portions of bone are depreffed, fo as 

 to comprefs the brain, the operation is ftill requifite, if they 

 cannot be elevated by other means. But Richerand main- 

 tains, that a positive indication for trepanning is not fre- 

 quent, either becaufe it is difficult to judge of the exillence 

 and fituation of extravafations, or becaufe extravafated 

 fluids readily efcape through the interfpaces of the frag- 

 ments, when the^'e is a fplintered fraAure. Such facility is 

 alfo increafed, when one of the portions of broken bone is 

 totally detached, fo that it can be removed, leaving an aper- 

 ture equivalent to what would be produced by the applica- 

 tion of the trepan. 



When the indications render it neceffary, there is no 

 point of the external furface of the cranium to which the 

 trepan, or trephine, may not be applied. The region of 

 the frontal fpine and fmufes, however, and the fituation of 

 the fpines and inequalities of the occiput, the lower part of 

 the fquamous portion of the temporal bone, and the track 

 of the meningeal artery running under the anterior inferior 

 angle of the parietal bone, are places to which the inftrument 

 ought never to be applied without urgent neceffity. The 

 furgeon may trepan upon the futures, and over the fmufes of 

 the dura mater, with perfeft fafety. A wound of the longi- 

 t'udinal fmus has not only been found to be free from danger, 

 but aftually beneficial, by the evacuation of blood that has 

 followed. The experience of Pott, Callifen, &c. confirms 

 this fail ; and they have even purpofely opened the velfel 

 with a lancet. Callifen, Syft. Chir. Hodiernse, torn. i. 

 p. 659. edit. 1798. 



The manner in which the two tables of the (kull recede 

 from each other at the frontal finufes, would make the 

 operation difficult. Befides, here the fpine of the os frontis 

 projedls inward, fo that the whole of the bone could not be 

 fawn through, without the dura mater being lacerated. 

 In an urgent cafe, however, the furgeon might trepan ex- 

 aftly on the frontal finus, by removing the outer table ot 

 that cavity with a large trephine, and applying a fmall one 

 to the inner table. Perhaps alfo, in thefe preffing examples, 

 it would be proper to trepan on the centre of the os frontis, 

 ,.nd ufe a chi(rel for breaking the inner fpine of that part of 

 the bone. In the fame way, although a furgeon would al- 

 ways prefer avoiding the meningeal artery, he ought not, in 

 urgent cafes, to be afraid of it. The beft modern furgeons 

 well know that the hsmorrhage from that velTel is capable 



of being eafily fupprelTed, by the introduftion of a fmull 

 plug into its orifice. 



The praftitioner can never be too careful not to place the 

 trepan on a loofe part of the fraftured bone, as it would be 

 apt to be preffed inward, fo as to do mifchief to the brain. 



When the cranium has been perforated with the trepan, 

 and nothing is found between the fliuU and the dura mater, 

 or underneath this membrane, in^the fituation where an ex- 

 travafation may be fufpefted to exift, additional perforations 

 are to be made elfewhere, if the fymptoms (hould indicate 

 fuch pratlice. The repetition of the trepan is particularly 

 requilite in cafes where the fiffure runs acrofs a future. 

 The intimate adhefion of the dura mater to the future, ex- 

 plains why this membrane often continues undetached in 

 that fituation, while on each fide it is feparated from the 

 bone, and blood effufed upon it. There are then two dif- 

 tinft extravafations, and two perforations of the bone are 

 abfolutely necelfary for the difcharge of the blood. 



Foreign furgeons invariably prefer, for the accomplifh- 

 ment of the operation, an inftrument called the trepan, 

 which much refembles a wimble, a tool extenfively em- 

 ployed by coopers, and, like it, confifts of a handle, to 

 which is adapted a circular faw, or, as it is termed, the 

 crown of the trepan. The diameter of the crowns varies 

 from fix to ten lines, and they are about one inch in height. 



In England, the trepan (P/a/c VIII. Surgery) has gone 

 into difufe, the trephine being generally preferred, though 

 perhaps without great reafon. The trephine differs from 

 the trepan in having its crown fixed upon and worked with 

 a common tranfverfe handle, inft,ead of being turned with a 

 handle like that of a wimble. On the continent it is ob- 

 jeded, that the trephine which the Enghfh furgeons make 

 ufe of, requires aftronger hand and greater preffure than the 

 trepan, fo that at the moment of finifhing the divifion of 

 the bone, one runs a rifk of forcing the inftrument too 

 deeply, and lacerating the brain and its membranes. We 

 muft confefs, however, that we have never feen this accident 

 occur, and the trephine is now made in fo excellent a 

 manner, that it will cut the bone fait enough without any 

 occafion for immoderate prefture. If fome badly made tre- 

 phines cut with too much difficulty, the trepan may be 

 accufed of dividing the bone with too much celerity. A 

 man of ordinary flcill may ufe either inftrument, and an 

 awkward praftitioner will be apt to do mifchief let him 

 employ which he will. See Trephine. 



The firft objeft in the performance of trepanning, is to 

 expofe the exaft part of tlie bone on which it is intended to 

 apply the inftrument. In fome cafes, the fcalp is fo torn 

 and injured, that a fufficient extent of the l]-;ull is already 

 uncovered, and it is unneceffary to employ a fcalpel. But 

 in the majority of inftances, the ufe of the knife muft pre- 

 cede that of the faw. Incifions of a crucial form, or fhaped 

 like the letter T or V, are found to be the moft eligible, 

 becaufe they allow their edges to be brought together again 

 with eafe, and they enable the furgeon to denude a larger 

 furface of bone than could be managed with an incifion of 

 a different figure, but of equal fize. The old furgeons 

 ignorantly made circular wounds, and without confideration 

 cut large portions of the fcalp away before they applied the 

 trepan. The confequence was, that the patient was fure of 

 being permanently disfigured, and the edges of the perfora- 

 tion, remaining for a long while uncovered, frequently 

 exfoliated. 



The generality of furgical authors next advife us to be 



careful to fcrape away the pericranium from the part to 



which the trepan, or trephine, is to be applied, fo as to let 



the law aft with more facility. We have never found this 



B b 2 proceeding 



