The invention relates to a surgical instrument which can advantageously be used especially for performing neuro- surgical operations _*

When performing neurosurgical operation e. . in cerebral surgery there is a grave problem to remove blood,

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secretions, etc., from the operative field - termed as suction - and to stop bleeding of the blood-vessels, to close the arteries - termed as coagulation - because the operative field is difficult and elaborate to reach, and because several kinds of surgical instruments have to be used alternately. Some of the instruments are connected to a high frequency power source, therefore the instruments must be electrically insulated in order to prevent "arcing" which may occur when two different instruments are present simultaneously e.g. in the skull. Such instruments are e.g. the so-called bipolar forceps being used to stop bleeding of the blood-vessels /coagulation/. This important group of instruments comprises about 40 to 50 units of different forms, and it depends on the organ to be operated and on the nature of the operation which kind of instrument is used. When using the bipolar forceps, the electric circuit is closed and the end of the blood-vessel be¬ ing pinched between the forceps is so to say "welded" by the high frequency current. Before introduction of the bipolar forceps, the sucker has to be removed. As a disadvantageous factor, separate persons are needed to handle the sucker and the bipolar forceps. These latter have also the disadvantage that due to mechanical overstrain and to the everyday gas sterilization, they deteriorate, get damaged very soon, and replacement of the unusable forceps demands time and expenses.

Suckers, as used today, are constructed as thin, rigid pipes made of a special metal or metal alloy, connected to the vacuum source of the operating-room and operated by temporary

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opening and closing the vacuum - as needed. Their up-to-date types are available - at very high prices - in form of sets comprising several pipes being bent at different - predetermined - angles. They are able to perform only one function i.e. sucking. A whole series of suckers with different bending angles are needed, as the more flexibly the sucker or the series of suckers reach that area where the fluids /superflous blood etc./ have to be sucked from, the more reduced the operative field may be. The specific expenses are even less favourable in the case of the so-called throw-away suckers destinated to a single application, while their value in use is not or at least not substantially better..

The invention aims at developing a surgical instrument especially for performing neurosurgical operations, which is sui¬ table to fulfil both the functions of sucking and coagulating, can be bent at any optional angles, is electrically insulated and resists mechanical stresses as well as gas sterilization.

The invention is based upon the recognition that when the sucker is made of a material which is easy to bend, well resists flexing, corrosion-proof, conducting and non-toxic, coated with a plastic material resisting flexing and gas sterilization in that area which contacts the operative field, except near to its tip, and when this sucker is equipped with an electric connector by the aid of which it can be connected to a high frequency power source, then both coagulating and sucking may be performed by one instrument of maximum flexibility.

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Based upon the above recognition the aim as set may be reached by means of a surgical instrument having a suction tube to be connected to a vacuum source, the suction tube being provided with a finger plate having a hole communicating with the inner space 'thereof, wherein the suction tube is formed as a flexible silver pipe, the portion of said suction tube reach¬ ing the locality of the operative field - with the exception of the pipe end functioning as coagulating end - being provided on its outer surface with an electrically insulating, flexible plastic coating, and that there is an electric connector enabling connection of the suction tube to a high frequency power source. Expediently, the suction tube has a plastic coat¬ ing made of a synthetic thermoplastic material of the polyamide type, being advantageously a plastic coating made of polyamide- -11 produced by condensation of 11-amino-undecane carboxylic acid of the formula based on castor oil.

According to a further feature of the invention, the electric connector is arranged between the finger plate and a connecting piece provided on the end of the suction tube being opposite to the coagulating end, and in a cable joined to the electric connector, there is inserted a pedal enabling switching on and off the electric circuito According to a further embodi¬ ment of the invention, the end portion of the suction tube functioning as a coagulating end, has a lower thickness and/or a smaller diameter than the other part of the tube. The plastic coating is present on the portion between the coagulating end and the finger plate and its length is several times, advantage¬ ously about 10 to 20 times longer than the length of the naked pipe end serving as the coagulating end. In order to enable

a more fine adjustment of the sucking effect, there may be formed in the finger plate two holes of different diameters communicating with the inner space of the tube.

Finally, it is advantageous when the electric connector and the electric cable joined thereto are connected together in a manner enabling their rotation in relation to each other, and when the instrument is equipped with a cleaning means con¬ sisting of a metal, expediently a steel filament having an outer diameter smaller than the inner diameter of the suction tube and of a handle arranged at the end thereof.

The invention will be described below under reference to the enclosed drawings which show an advantageous embodiment of the instrument as well as a possible mode of its use. In the drawing Figo 1 is showing the instrument in a longitudinal axial section, partly in side elevation; Figo 2 is a view taken in the direction of arrow A according to Fig. 1; Figo 3 is showing the instrument according to Figs. 1 and 2 in use, during performing an operation; showing also the auxiliaries needed to operate the instrument connected thereto; Fig. 4 is showing a means for cleaning the instrument accord¬

The surgical instrument as shown in Figs. 1 and 2, having as a whole the reference numeral 1, comprises a suction tube 2 made of silver, having a diameter of e.g. 0,5 to 1 mm ^" and a length of about e.g. 20 cm. At one end of the suction tube 2 there is arranged a connecting piece 3 by the aid of

which a hose 10 shown with dotted lines in Figs. 1 and 2 can be connected to the suction tube 2; the function of the hose 10 will be described later.

The end of the suction tube 2 being opposite to the connecting piece 3 serves for performing coagulation; this coagulating end is marked with reference numeral 5 - The coagulat ing end 5 of a length a. /the value of a may be a few millimeters conveniently does not exceed 1 cm/ is naked i.e. it is formed by the silver pipe itself, while a portion H extending behind the coagulating end 5 towards the connecting piece 3 having a

length of cca. 10 to 20 cm is provided with a plastic coating 4« It is understood that the numerical data are only of inform¬ ative character, the instrument may be constructed also with different sizes.

The silver pipe manufactured of industrial silver by drawing, has excellent properties for performing the operations aimed at with the instrument, it can be made flexible by heat treatment, resists even frequent flexing, has a favourable electric conductivity, can be sterilized, is non-toxic, fully corrosion-proof and, finally, plastics can excellently adhere theretoe

Also the plastic coating 4 has to be non-toxic and sterilizable, moreover it has to resist gas sterilization. It must, similarly to the silver pipe, be flexible and resist frequent flexing i.e. mechanical stresses. Further, it must be an electrically insulating material. All these requirements are met by synthetic thermoplastic materials of the polyamide type. The raw material used for the manufacture is castor oil comprising mainly glycerides of ricinoleic acid. The castor oil

is converted with methanol into ricinoleic acid ester. Under the effect of heat treatment, the esters of the ricinoleic acid will be decomposed to enanthol and undecylenic acid methyl ester, this latter being hydrolizable to undecylenic acid which is converted by amination into 11-amino-undecane carboxylic acid. Therefrom polyamid-11 is formed by plycondensation, having the following formula:

H/SN-/CH ₂ / ₁₀ -C07nOH. This product is marketed in form of granules or powder under the name RILSAN. The powdered product is then applied - by hot melting techniques - onto the outer surface of the suctio tube 2 made of heat treated silver, over the portion of a length H as mentioned above /Fig. 1/, forming thereby a minimum thick¬ ness /in the order of a few tenth of millimeter/ plastic coat¬ ing 4.

As shown in Fig. 1 - going on from the coagulation end 5 towards the connecting piece 3 - there are connected to the suction pipe 2 first a finger plate 7 then an electric connector 6. The finger plate 7 can be fixed e.g. by welding or by solder¬ ing to the suction tube 2, it is oviform and its size corres¬ ponds to that of the thumb. In the finger plate 7 there are formed a big hole 8 and a minor hole 9, both communicating with the inner space of the suction tube 2, and sucking may be controlled, started, stopped and interrupted by either holding or making them free.

Between the finger plate 7 and the connecting piece 3 there is fixed to the suction tube 2 the electric connector 6- made expediently also of industrial silver, through which an electric connection may be established between the suction tube

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2 and the high frequency power source, by inserting a plug 20 attached to an electric cable 14 into the socket 6a /Fig. 3/ _* In Fig. 2 the cable 14 and the plug 20 are shown in dotted lines. Conveniently, the plug 20 is an interchangeable piece ensuring that all electric instruments used in the operating- -room can be powered via the cable 14, besides, the plug and the connector are connected together by a turning joint, thus, the operating surgeon may use the instrument by turning it in any directions.

In Fig. 3 there is shown the mode of use of the surgical instrument 1 according to the invention. The hose 10 /usually rubber hose/ adjoining to the connecting piece 3 /Fig. 1/ leads as shown by arrow b to a vacuum source /not shown/. The electric cable 14 connected to the electric connector 6 leads to the high frequency apparatus 11, which again is connected by means of an electric cable 21 to a 220 V power source e.g. to the electric network, as shown by arrow _c. It is to be noted that the high frequency apparatus is known per se and may be e.g. of the type ERBOTOM. It is also well known that in hospitals, there is usually available a central vacuum source as it is needed also for other purposes. To a branch 22 of the electric cable 14 there is connected a pedal 15o By operating this pedal 15, the instrument 1 may optionally be connected either to the vacuum to perform suction, or to the high frequency power source to perform coagulation /i.eo stopping of the blood vessels/. Also to the high frequency apparatus 11 /power source/ is joined an electric cable 16 at the end of - which there is arranged a body electrode 12 to be fixed during

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operation onto the body surface of the patient 17- The oper¬ ating table 13 is shown only symbolically; it is connected to earth.

The instrument 1 according to the invention is function¬ ing during operation of e.g. a brain-tumour as follows:

In the skull of the patient 17 there is prepared - in a manner known per se - a hole 19 by cutting out a piece of the skull and the tumour 18 marked with dotted lines in Fig. 3 is exposed, then removed. During operation, by means of the instrument 1 both the blood, secretion, etc. may be sucked from the operative field and the intersected blood vessels can be coagulated. The respective actions may be performed con¬ secutively by means of a single instrument without the need to remove it from the operative field. In order to perform alternately both actions, the operating surgeon has only to depress the pedal 15 and during sucking action, the control of suction and regulation of the sucking intensity may optional¬ ly be performed by temporary closing and opening the holes 8, 9 with the thumb. The minor hole 9 is provided in order to enable a more fine control of the sucking effect, it is used first of all in special operations /e.g. in the case of aneurysme/o The access to the operative field - in the present case to the area round the tumour - is excellently ensured by the instrument 1 thereby that the suction tube 2 together with the coating 4 may optionally be bent even during the operation, thus, every point of the operative field may perfectly be reached during the whole process of the operation, in order to perform either suction or coagulation.

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The cleaning means 23 shown in Fig. 4 is an essential accessory of the instrument according to the invention. It consists of a filament 24 of spring steel /stylet/ and of a handle 25 formed on one end thereof. By drawing the filament 24 through the tube 2, the instrument 1 can be cleaned both during operation or thereafter. The length of the filament 24 expediently exceeds the whole length of the tube 2.

The advantageous effects attached to the invention are as follows:

This single instrument in itself is able to perform two functions which until now could be performed not only by two separate instruments but actually by to separate sets of instruments. A set of the known rigid suckers comprises e.g. ten to twenty pipes bent at different angles in order that different points of the operative field may be reached there¬ with. Whereas, the instrument according to the invention may be bent at any optional angles - even during operation - thus, it may be adapted much more flexibly to the function to be performed than a whole set of rigid suckers comprising any number of pipes. Also the bipolar forceps used till now for coagulation are marketed in form of sets and it is obvious that the operating surgeon can better reach the blood vessels to be stopped at any point of the operative field by using the instrument according to the invention which may optional¬ ly be bent in any directions, than by using the known bipolar forceps. Handling this latter is more complicated than the use of the instrument according to the invention, because the blood vessel to be coagulated has to be squeezed by the forceps while our instrument needs only to be touched to the

blood vessel to be stopped; thus, when using the instrument according to the invention, coagulation takes place only on that desired small area where it is needed - this is due also to the insulating plastic coating - and meanwhile the instru¬ ment needs not to be kept away from the surroundings of the operative field being otherwise very limited. Besides, sucking and coagulating operations may be performed subsequently, alternately or, in principle, even simultaneously by means of the instrument according to the invention, and the instrument needs - as mentioned already - not to be removed from the oper¬ ative field even in the case when also other instruments are applied there, because the plastic coating guarantees the electric insulation, thus, an electric arching may not occur between the different instruments. Both the silver and the polya ide-type plastic can be well sterilized, easily flexed and resist well mechanical stresses, so e.g. frequent flexing in alternate directions. Both the silver and the plastic material are non-toxic. The plastic coating may be manufactured in various colours which may involve practical advantages. Due to the advantageous properties of the instrument as set forth above, one hand of the surgeon becames free during operation, besides the rotating connection between the cable and the instrument enables to the surgeon to perform the operations very easily, the instrument accomodating to the palm of the hand does not impede the fine motions and, a main activity of the staff, namely to ensure connection between the cable and the instrument - often associated with contact failures - may be omitted, so that the staff can better assist in the

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surgical part of the operation. Due to the flexible tube being able to bend in any directions, only a minimum area has to be opened as operative field. Yet, the visibility and access- ability to the operative field is better, the operation may be performed faster and due to the significantly limited oper¬ ative time, the patient has better possibility to survive - e.g. in case of brain operations or other severe neuromuscular operations. Transfusion is needed at a reduced extent and due to the limited operative time, the utilization of the operat¬ ing room can. be improved. The instrument may be manufactured in several e.g. 8 to 10 sizes different lengths and/or thick¬ nesses and/or outer or inner diameters, etc_»7» according to the requirements as raised by different operations. The instru¬ ment is extraordinarily suitable for brain and spinal operations to be performed within deep, narrow holes and also for other operations being practically insolvable with the instruments as used today. Finally, the manufacturing costs of the instru¬ ment according to the invention are lower than that of the conventional instruments.

The invention is of course not restricted to the embodiment described above in details, but it may be realized in many other ways within the scope of the claims.

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