Surgical aid

The invention proposes a surgical aid which contains pharmaceutical active compounds in support materials which permit protracted release of the active compounds, this aid being designed in the form of a flat article provided with free spaces, and, as a rule, the individual free spaces having, at least predominantly, an area of at least 0.1 cm.sup.2.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a surgical aid which contains pharmaceutical 
active compounds in support materials which permit protracted release of 
the active compounds. 
2. Technical Considerations and Prior Art 
Agents which contain antibiotics and are used as surgical materials for 
controlling infections have been disclosed in German Patent Specification 
No. 2,320,373. They are used for, for example, in filling osteomyelitic 
cavities and are used in the form of beads which are connected together by 
means of threads or wires. These beads, which are produced from a material 
which is not absorbable by the body, must subsequently be surgically 
removed from the wound and thus cannot be advantageously used for managing 
infections of soft tissues. In addition, it is only possible with great 
difficulty to chieve uniform distribution of the beads over a relatively 
large wound area. 
The use of partially absorbable multicomponent compositions which are based 
on physiologically tolerated substances and contain medicaments and which 
are intended to serve as a permanent replacement for bone and, with this 
object, are completely integrated into the biological system, without 
there being the necessity for later reoperation to remove the implant, are 
known from German Specification No. 2,917,037. This composition, which 
takes the form of granules or a moulded composition, cannot be used for 
managing normal wounds since integration into the bone is impossible in 
this instance. 
SUMMARY OF THE INVENTION 
Thus, an object of this invention was to find a surgical aid which is 
suitable for absorbing and releasing, in a protracted manner, medical 
active compounds and which, in particular, can also be used for normal 
wounds. 
Another object was to design the agent such that uniting the tissue in the 
surfaces of the wound can take place as far as possible uninhindered, 
without the surgical aid which is used interfering with this reuniting or 
there being a necessity for its later removal. 
Finally, still another object was to design the agent such that it permits 
medical active compounds to be placed so as to act at sites which can be 
accurately determined beforehand, for example in a uniform distribution 
over the entire wound area, or specifically localised at one or more 
points. 
This object has been achieved by the present invention. 
Thus the invention relates to a surgical aid, which contains pharmaceutical 
active compounds in support materials which permit protracted release of 
the active compounds, and which is characterised in that it is designed in 
the form of a flat article provided with free spaces, as a rule the 
individual free spaces having, at least predominantly, an area of at least 
0.1 cm.sup.2. 
A significant advantage of the aids according to the invention is that 
medical active compounds can be introduced into the body at defined 
spacings from one another and thus in an exactly defined spatial 
distribution, and can display their actions at sites in the body which can 
be accurately determined beforehand. Direct contact with the surfaces of 
the wound, and thus healing without difficulty and without the formation 
of scar tissue, is made possible by the flat design of the aid and the 
high proportion of free spaces. The aids can be designed in the form of, 
for example, lattices or perforated plates which have free spaces which 
are sufficiently large for the tissue in the surfaces of the wound to 
unite.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS 
Some preferred embodiments of the invention are shown in the drawings. FIG. 
1 shows a plan view of a flat article made of absorbable threads (2) which 
form a lattice, the active compounds which become medicinally effective 
being located at the points of intersection (1) of the lattice. FIG. 2 
shows a cross-section along the line II--II through a lattice of FIG. 1 
which has been inserted into a wound. 
In this embodiment, the threads (2) which form the lattice are designed to 
be relatively thin, and the significant mass is localised at the points of 
intersection. This has the advantage that the surfaces of the wound (3) 
can come into direct contact over significant areas of the wound. The 
active compounds are essentially localised at the points of intersection 
(1) from where diffusion into the surrounding free spaces takes place. 
However, it is obvious that the threads (2) can also contain active 
compounds. 
FIG. 3 shows a flat article which is designed as a plate (4) containing 
free spaces (5). It is possible and preferable for this plate to be 
composed entirely of an absorbable material which contains the active 
compounds to be released. However, it is also possible in principle for 
some of the free spaces (5) to be charged with moulded items containing 
active compound, while the free spaces (5) which remain empty permit the 
tissue in the two layers of the wound which are separated from one another 
to unite. In this instance, it is possible to use, for example, the beads 
known from German Patent Specification No. 2,320,373, and these can, where 
appropriate, be connected together by wires or threads so that, after 
absorption of the plate (4), the beads can be withdrawn in a manner known 
per se. However, due to the arrangement of the beads in the plate, uniform 
distribution of the active compounds in the area of the wound is made 
possible on the one hand, and entanglement of the beads on withdrawal is 
prevented on the other hand. 
FIG. 4 shows a flat article which is again designed as a lattice (6). It is 
possible for this lattice to be used for immobilising moulded items 
containing active compounds, and these are designed as beads (7) in this 
instance. However, as an alternative or supplement to this, it is also 
possible for the lattice itself to be composed of material containing 
active compound. In this instance, it is also possible, inter alia, to 
charge the lattice (6) and the moulded items (7) with different active 
compounds. Due to the greater mobility of the lattice (6) compared with 
the plate (4), it is possible to immobilise the moulded items (7) 
containing active compounds in any desired spatial distribution, for 
example even around a bone or stump of bone. 
As a rule, the aids according to the invention are manufactured from an 
absorbable material which is tolerated by the body. Large numbers of such 
materials are known and have already been proposed for other surgical 
purposes. In this context, the following are merely mentioned as examples: 
polyglycolides, polylactides, polyhydroxycarboxylic acids, polyamino acids 
and collagen. However,in certain cases it can also be necessary to use 
non-absorbable materials. This is the case, for example, when the active 
compounds contained in the flat articles are not degraded in the body but, 
like, for example, radioisotopes, must be removed again from the body 
after a certain duration of action. A lattice which is not dissolved can 
be removed again from the body relatively easily, but good spatial 
distribution of the active compounds is ensured during the time it is 
present in the body. 
When using radioisotopes, for example, it can also be advantageous to use 
the moulded item shown in FIG. 5, which comprises a capsule (8) into which 
a radioisotope (9) can be introduced. The capsule (8) is manufactured from 
a non-absorbable material, such as, for example, an acrylate polymer, in 
the form of half-shells which, after introducing the emitter, can be 
bonded or sealed together so as to form a shell which surrounds the 
radioactive isotope 9. This type of capsule (8) can be held in the body by 
an absorbable lattice in accordance with FIG. 1 or 4 or an absorbable 
plate in accordance with FIG. 3. It is ensured, by becoming embedded in 
the wound and by the absorption of the lattice, that the capsule is 
located at the desired site and remains there so that the exposure to 
radiation can be accurately controlled, and desired localised irradiation 
can be achieved without there being a need to fear that the capsule can be 
displaced when the patient moves. As soon as the areas of the wound have 
grown together through the lattice or the plate, displacement of the 
capsule (8) is no longer possible. In this instance, the active compounds, 
for example antibacterials, contained in the lattice or plate ensure that 
healing of the areas of the wound takes place without difficulty. 
The term "active compound" is employed in a very wide sense and comprises 
all items for parenteral use which are intended for curing, alleviating, 
treating and/or preventing illnesses in humans and animals, or are able to 
influence a bodily function of humans or animals. 
Antibacterial active compounds of a variety of types, in particular 
antibiotics, should be particularly mentioned. Their spectrum of action 
should comprise Gram-positive or Gram-negative pathogens or, preferably, 
both groups. Where, possible, the induction of resistance in the pathogens 
by the active compounds should be only slow or zero. Of the antibacterial 
active compounds, the following antibiotics may be picked out as examples; 
aminoglycoside antibiotics, such as amikacin, butirosin, dideoxykanamycin B 
(DKB), fortimycin, gentamycin, kanamycin, lividomycin, neomycin, 
netilmicin, ribostamycin, sagamycins, seldomycins and their epimers, 
sisomicin, sorbistin, tobramycin, streptomycins; lincoycins, such as 
clindamycin and lincomycin, and rifamycins, such as rifampicin and 
rifamycin. 
The aminoglycoside antibiotics, especially gentamycin, are particularly 
suitable for this purpose because of their broad spectrum of antibacterial 
action. 
It is also possible to combine together two or more of these antibiotics, 
for example gentamycin with clindamycin; in addition, combinations of 
these antibiotics with other active compounds, for example with 
antiseptics, are suitable. 
Other active compounds are also preferred, for example antiseptics (such as 
bromochlorophene, hexetidine, buclosamide, salicylic acid, cerium nitrate, 
chlorhexidine, 5-chloro-8-hydroxyquinoline, copper 8-hydroxyquinolate, 
acridine orange, undecenoic acid, undecoylium chloride, silver salts, such 
as silver sulfadiazine, mafenide, nitrofurazone, cloflucarban, 
tribromsalan, taurolin and noxythiolin), tuberculostatics, such as, for 
example, streptomycin, rifamycins and isonicotinoyl hydrazide, also 
antiinflammatories (such as salicylates, phenylbutazones, indometacin, 
ibuprofen, p-aminophenol derivatives [for example acetaminophene], 
pyrazolones and hydrocortisone palmitate) and cytostatics (such as 
methotrexate, fluorouracil, vinblastin, doxorubicin and prednisone). Where 
appropriate, it is also possible to combine together active compounds 
directed at different indications. 
It is also possible to adjust the mode of release of the active compounds 
to suit requirements. Thus, on the one hand, it is possible to control the 
rate of release by the selection of the support material and the 
concentration of the active compound in the support material. On the other 
hand, it is also possible specifically to reduce the solubility of the 
active compound and thus to achieve greater retardation. For this purpose, 
especially for antibiotics, but also for other groups of active compounds, 
the formation of sparingly soluble salts can be carried out in many cases. 
For example, it is particularly suitable for aminoglycoside antibiotics to 
form salts with phosphoric esters of hydroxyflavanoids. 
The amount of active compounds to be added can be varied within wide limits 
and essentially depends on its activity. In general, the amount of the 
active compound is between about 0.2 and 20% by weight, preferably about 
5-15% by weight, relative to the surgical aid. However, in individual 
cases, it is necessary to aim at the tissue concentrations which are 
necessary to influece the illness effectively. 
The surgical aid according to the invention provides immobilisation for 
medically effective active compounds directly at the site where there is a 
therapeutic necessity for this. At the same time, it makes it possible for 
the surgeon to select, depending on the use for a particular case, the 
desired dose which is already determined during production of the flat 
article. It is essential that the free spaces present in the flat article 
are sufficiently large to permit the tissue of the wounds to unite. Thus, 
the proportion of these free spaces in the total area is preferably at 
least 60% and, where appropriate, even 75% or above. Moreover, each 
individual free space should have an area of at least about 0.1 cm.sup.2, 
preferably at least about 0.25 cm.sup.2. However, it is also possible to 
produce free spaces of a size ranging up to several square centimeters, 
and this is very advantageous, particularly in respect of the direct 
uniting of the surfaces of the wound. 
Thus, the invention makes available a new and very advantageous surgical 
aid.