Trephine.

Application filed August 8, 1908. Serial No. 447,579.

To all whom it may concern:

Be it known that I, William Henry Hudson, a citizen of the United States, residing at Montgomery, in the county of Montgom5 ery and State of Alabama, have invented certain new and useful Improvements in Trephines, of which the following is a specification.

The present invention relates to that class 10 of surgical instruments known as trephines.

It has for its object the provision of an instrument which will eliminate the danger, heretofore present in trephining, of cutting through the bony structure of the skull and 15 puncturing the covering of the brain or the brain proper, unless the utmost care be exercised and the depth of the cut be accurately gaged by frequent observations during the operation. This elimination of dangerous 20 cutting is secured by providing the instrument with means for effecting an automatic stopping of the advance of the cutting portion so soon as such cutting portion has perforated the skull and resistance to the action 25 of the cutting portion ceases; and, stated more specifically, the invention contemplates providing a trephining instrument with cutting teeth, combined with which are stopping wings adapted to engage the wall of 30 the perforation and stop the advance of the tool immediately the cutting teeth have perforated the bone and resistance to the action of the cutting teeth ceases.

In order that the invention may· be 35 thoroughly understood by those skilled in the art to which it belongs, I have illustrated in the drawings herewith several embodiments of my invention, and in said drawings, Figure 1 is a side'view of a tre40 phine constructed in accordance with my invention. Fig. 2 is a sectional view of the trephine shown in Fig. 1. Fig. 3 is a bottom view of the same. Fag. 4 is a side view of a perforator. Fig. 5 is a bottom view of the 45 perforator, shown in Fig. 4. Fig. 6 is a side view of the follower. Fig. 7 is a bottom view of the follower shown in Fig. 6.

Referring to the drawings by numerals, like numbers indicating like parts in the sev50 era! views, 2 indicates the shank of the tool, which is of ordinary or any desired construction and adapted to be placed in a hand-bit or engine-chuck, as may be desired.

The active head of the tool comprises cut55 ting teeth 3. (see Fig. 1), which are of the type commonly used in trephines, and which form the active entering or perforating portion of the tool, and which, when the tool is operated, penetrate the bone and feed forward in the usual manner, Extending from GO said cutting teeth 3, but at an angle thereto are wings 4, the said wings 4 being arranged also at an angle relative to the longitudinal axis of the tool, as shown.

The wings 4 are somewhat sharply in- 65 dined to the longitudinal axis of the tool and will follow the lead of the teeth 3 so long as the teeth find resistance to their cutting action, but so soon as the cutting teeth 3 perforate the bone and resistapce ceases, 70 the wings 4 take on a screw-like action and, biting in the Avail of the perforation, check the tool and bind it against further advance.

As is well known the skull at its thicker portions presents a structure of different 75 character being made up of a hard outer plate, an intermediate spongy or cellular structure, and an inner hard plate, and in order that the tool may not be checked Avhen the cutting teeth enter the intermediate or 80 cellular layer, as Avould be the case if the Avings 4 continued in .the same direction around the head or body of the trephine OAving to the temporary reduced resistance to the advance of the cutting teeth as they 85 enter the cellular portion and the resultant tendency to lock and bind, I preferably provide the extension Avings 5 which, as clearly shown in Fig. 1, are not so much inclined to the. longitudinal axis of the tool as are 90 the Avings 4 and are practically continuations of the Avings 4,' being joined thereto at the point 7 on curved lines. I have found that by thus varying the angles of the two sets of stopping Avings 4 and 5, danger of 95 checking the tool when the cutting teeth strike the cellular portion of the skull is eliminated, and that the tool as thus made will feed through this cellular structure Avhich offers less resistance, and Avill only be 100 checked or stopped- when resistance to' the action of the cutting teeth occurs by reason of an actual perforation and complete severance of the button.

Preferably the wings 4 and 5 are sep- id arated by round grooves 6 so that good clearance will be secured and danger of choking the tool with bone dust eliminated, and I find further that by joining the wings 4 and 5 on a curve as shown at 7, instead of no at an abrupt angle, a much smoother operation of the tool is secured.

930,477 ing trephine is shown with mv invenLn η»’ ί -^{he 17 and 18 wiU} with plied thereto, the usual center nin 8 i<s nm ^areil™^lnS' action, but the instant the point but the e.ISp„ Ξ iZed l«d U>e tooithe ·μ„ „„j ------, .e^v'*^uc“ ”iui alternate libs and grooves which form clearance chanbnS ·^{νίι11 of the} trephine ,_ft n?n « t^th® .body-portion 9 of the center10 pm 8. By this construction, while the cenX?·^{111 boa}7 ^W1U>ave a close sliding fit within _the bore of the trephine, all danger fHp^Ph^afi^1C1Q^S ?ti?°^{ne dust} i^amming between . _e £ ££9 °^f l^he ^ter-pm and the wall of ¹³ L„L-^tri^plu^? bore is eliminated, as these particles will pass into the clearance grooves. k^urtb®^a°re. these clearance grooves have the additional function of engaging the center-pm holding-iugIQ (see so that 20 when the center-pin is inserted any one of m^Cef™o^ves may engage the holding-lug 10 and the necessity of inserting the center-pin 8 in a certain angular relation in the trephine bore to engage said lug is done ® way with. The body^rtioi 2 of the t “ phme is provided with the usual slot 11 in WiS^t0center-pin or the bone button to be pushed out, and said slot 11 opens into an elongated bore 12 which re30 ceives a relatively short tail 13 extending' upwardly from the body-portion 9 of the center-pm 8, this extended bore providing a relatively large opening and one in which there is no danger of dust collecting and 35 jamming, the tail 13 of the center-pin 8 when it is inserted. Preferably the tail 13 is provided with alternate ribs and grooves m the same manner as the bhdy 9 so as to /n n J^ammmg and provide clearance 40 spaces for bone dust.

the form of the tool shown in Figs. 4 and 5, in which a perforator is shown, an ordinary diamond-shaped point 16 is provided, and from this point extend wings 17 45 and 18, the wings 11 running directly from the point 16, as shown in Fig. 5, while the wings 18 branch from' the wings 17 just be°.^{w 01}L ^a7^a7 f¹;⁰™ the . point 16, the said v mgs 18 it will be apparent have a different a0. relation to the point .16 than do the wings U, the wings 17 being extended from the ^Puu\r^{n ea}?b ^side so as to form together with the point 16 the drilling and cutting instrumentality, while the wings 18 since 55 they do not come to the center 16 but branch tiorn the periphery of the cutting wiims 17 • appoints offset or to one side of the point 16, will engage and bite into the walls of the perforation immediately the leading cut or 60 action of the point 16 and wings 17 ceases, which will occur, of course, as soon as the point 16 penetrates the skull and resistance to its advance ceases.

r thp^T?A ^W'T -⁷i^{and 18 r,,n} Preferably in 65 the form of spirals,’and so long as the point

4&lt;/i —“‘6° m- a screw^ 70 like fashion, biting mto the wall of the perfoiation and binding the tool against further lotation in the same manner as in the form shown m Figs. 1, 2 and 3.

5n'wi&lt;i^e«^adaj^tr^tl^ⁿ-^{of my} invention shown 75 in Figs. 6 and-7, it is applied to a follower designed to follow the preliminary perfora-’ ίίΓwhirl l^{by tll}®.P^erforai°r just described, fae7of th? i ^CV ^{teeth 14 lie across tll}e · race of the tool and meet at a smooth dull so center 14* instead of having a hollow or bored-out body-portion, so that while the cutting teeth 14 have an efficient action, the point 14* is smooth and has no penetrating' action this tool being adapted to drill a clean ₈₅ns ?η^ΓΚ¹⁰ί ^lnste1^{ad of} Putting out a button, as in the form heretofore described. This action of the teeth is the same, and their angular relation is generically the same as that described in connection with the other 90 forms, for when the cutting teeth 14 perforate the bone and resistance to their advance ceases the stopping teeth or wings 15 take hold of the wall of the perforation and stop the advance of the tool. (J5

It will be seen that in the operation of the ο// .^forn?^s shown, so long as the cutting teeth or point find an active resistance to their advance they will continue to cut and whH ^f2^{rward u}.^nder .^the necessary pressure, ioo while the stopping wings will simply follow without biting into the wall of the perforation until the perforation is completed by the cutting teeth or point and resistance to their advance ceases, whereupon the stopping 105 wings will operate with a screw like action, biting into the wall of the perforation and stopping the tool at once, so that the operator, by the checking of the tool, will not only be advised of completion of the perforation, out unless an enormous turning pressure be applied sufficient to splinter or shatter the Ϊ1Ϊ1 V^irea ™^unding the perforation, he ^WJu be unable to advance the tool further.

W hile I have shown a particular embodiIi/i invention I wish it to be understood that this is merely illustrative and not restrictive of my invention, and as I be.J^eve that I am the first to provide a tool of the character described, which has means for automatically stopping its advance so soon as the cutting teeth cease to meet with resistance, I do not limit myself to any of the details shown and described except so far as I am limited by the prior art to which the invention belongs.