T R E 



T R E 



TREOGAN, a town of France, in the departraervt of 

 the North Coaih ; 9 miles W.S.W. of Roftrenen. 



TREOGAT, a town of France, in the department of 

 the Finifterre ; 9 miles S.W. of Quimper. 



TREPAN, in Surgery, a circular faw, by means of which 

 the (kuU is perforated in the operation called trepanning. It 

 bt-ars a confiderable refemblance to the well-known inftru- 

 mi?nt named a wimble, and is worked in the fame manner. 

 A reprefentation of it is given in Plate WW. Jig. 6. of the 

 furgical plates. Formerly, the faw was fometimes made of a 

 conical (hape (fee_^^. 5.); but this conftruftion rendered 

 the aftion of the inftrument difficult ; and as the fear of a 

 cylindrical law penetrating too fuddenly, fo as to injure the 

 brain, was found by experience to be an infufficient reafon 

 for the conical (hape of the faw, the cylindrical trepan at 

 length came into general ufe. In this country, the trepan is 

 now fuperfeded by the inftrument called a trephine, which has 

 a diffei-ent kind of handle from that of the trepan, and is not 

 worked in the fame way. (SeeTREPHiNE.) On the continent, 

 however, the trepan ftill has the preference. Mr. Rodman's 

 trepan [Jig. i . ) is objeftionable, becaufc with it you cannot 

 increafe and diminifh the preffure on any particular point of 

 the circular groove in the bone, as occafion requires. You 

 muil continue to faw every part of the circle. Hence, if 

 the bone be fawn through in one place, and not in another, 

 as generally happens before the operation is finifhed, the 

 further aftion of Mr. Rodman's faw will inevitably do 

 mifchief to the dura mater, and is not well calculated for 

 completing the divifion of the bone. See the following 

 article. 



TREPANNING, or Trephining. From what has 

 been faid in fome preceding articles of this work, (fee par- 

 ticularly Hear, Injuries oj. Extravasation, &c.) the 

 operation of trepanning or trephining, or that of fawing 

 out a portion of the fkuU, is, in feveral affeftions of the 

 brain from compreflion or irritation, the only means of 

 preferving life, and of all other remedies the moft urgent 

 and effedlual. It fliould be performed in good time, and 

 the repetition made according to the exigency of the cafe. 

 In the records of furgery, innumerable fafts may be con- 

 fulted, where the prudent and judicious employment of the 

 trepan has effefted wonderful cures, and been the only thing 

 by which the patients' lives could poffibly have been faved. 

 The benefit which the operation brings about, is alfo fome- 

 times fo fudden and aftonifhing, that in no inftance does the 

 iiiterpofition of the furgical art difplay itfelf to greater ad- 

 vantage. The immediate reftoration of fight by the depref- 

 fion or extraction of an opaque fubftance from the eye, is 

 not more beautiful and ftriking, than the inftantaneous com- 

 munication of the inlelleftual faculties, and of the powers of 

 fpeech, of feeling, &c. together with voluntary motion, to a 

 perfon lying in an apparently lifelefs ftate from an injury of the 

 head. The utihty of the trepan is occafionally manifeiied even 

 in this degree. In the valuable elTay of Mr. Abernethy on 

 injuries of the head, a cafe may be feen, in which the pa- 

 tient, who had been in a condition almoft bereft of anima- 

 tion, fofe up and fpoke the inftant the extravafated blood 

 was removed from the furface of the brain. And amono- the 

 wounded at the battle of Waterloo, there was a foldier of 

 the 44tir regiment, whofe cafe is of equal intereft. He had 

 been ftruck with a mulket-ball on the right parietal bone, 

 which was expofed, and had no appearance of being fraftured. 

 As, however, the fymptoras of compreflion were urgent, and 

 the patient was in nearly a lifelefs ftate, the writer of the 

 prefent article conceived it right to apply the trephine to the 

 part on which the violence had ailed. He had not fawn 

 long before the external table caliie away in the hollow of 



the trephine, leaving the inner table behind, wliich was not 

 only fplintered, but driven at one point more than half an 

 inch into the membranes and fubftance of the brain. No 

 fooner were the fragmerts taken out \vith a pair of forceps, 

 than the man inftantly fat up in his bed, looked round, and 

 began to fpeak with the utmoft rationality. It is a moft ex- 

 traordinary faft, that this patient got up and drefl^-d himfelf 

 the fame day without leave from the medical officers, and 

 never had a bad fymptom afterwards. Immediately the 

 operation was finifhed, the temporal arteries were opened, 

 and fome purgative medicines exhibited. 



Let not the young furgeon, however, draw from thefe 

 dazzling cafes of fuccefs an immoderate fohcitude to per- 

 form the operation ; for it (hould never be undertaken but 

 in the moft preffing circumftances, and when the fymptoras 

 unequivocally Ihew, that a dangerous degree of preflure on 

 the brain exifts. We recolleft an unfortunate example, in 

 which an hofpital furgeon of this metropolis ventured to 

 faw out a portion of the frontal bone for a mere long-con- 

 tinued pain in the part : the patient was attacked with in- 

 flammation of the dura mater, and perifhed in three or four 

 days. We may therefore conclude, that the operation is 

 not itfelf exempt from danger ; and it is certain that it 

 ought never to be refolved on without deep confideration. 

 " Gravis tamen fatis eft operatio, ut nunquam, nifi indica- 

 tiones fufficientes adfint, inftitui debet." Callifen Syft. 

 Chir. Hodiern. torn. i. p. 658. 



The trepan or trephine is never neceflary in injuries of 

 the head, except for the purpofe of relieving the brain 

 from preflure. Such preflure may be caufed by a deprefled 

 portion of the cranium, or it may be produced by an ex- 

 travafation of blood, or the lodgment of matter, betwixt 

 the fliuU and the dura mater. The chief danger of concuf- 

 fion, when the accident is not directly or foon fatal from 

 the diforganization and mifchief done to the brain, depends 

 upon the confequent inflammation of this organ, and there, 

 fore can be little likely to be benefited by the ufe of the 

 trepan. If the operation becomes proper in fuch a cafe, it 

 is when an abfcefs has formed under the cranium, and when 

 the confined matter itfelf creates bad fymptoms by its pref- 

 fure on the brain. This ftate of things, however, cannot 

 come on till after the inflammation of the brain and its 

 membranes has prevailed a certain time, and it is always ac- 

 companied with a detachment of the pericranium and a pufly 

 tumour of the fcalp ; or, if there be a wound of the latter 

 part immediately over the abfcefs, the lips of the injury ac- 

 quire fuddenly an unfavourable appearance, and lofe their ver- 

 milion colour. The patient has alfo had much preceding 

 febrile diforder, pain and tenfion over the whole head, red- 

 nefs and turgefcence of the eyes, and generally more or lefs 

 dehrium. When the matter is forming, there are ufually 

 fome rigors, and as foon as it is formed, the patient falls 

 into a comatofe ftate, and paralytic fymptoms fliew them- 

 felves. Here the urgency for the prompt application of 

 the trepliine is very great, and the patient's chance of living 

 is almoft eifentially connefted with the immediate perform- 

 ance of the operation. This important cafe has been par- 

 ticularly dwelt upon in the writings of Mr. Pott. 



In the articles Head, Injuries of. Extravasation, &c. 

 we have laid down the moft remarkable fymptoms of con- 

 cuflion and compreflion of the brain, a fubjcft which every 

 furgeon (hould ftudy with earneft attention, before he ever 

 prefumes to emplo)' the trepan. For fometimes tiiefe ac- 

 cidents are extremely difficult to be difcriminated ; fome- 

 times they exift together in the fame individual, a comphca- 

 tion which is peculiarly cmbarrafling ; and in every in- 

 ftance where the fymptoms are thofe of concuffion, the 



oper- 



