Disposable grafting knife

A disposable gingival grafting knife is described which comprises a narrow blade sharpened on one side, formed to define a preselected cross-sectional shape of the graft and embedded into the end of a sterilizable handle to define preselected width and thickness for the graft, and a tissue graft receptacle removably attachable to the back of the knife near the blade for catching the harvested graft.

BACKGROUND OF THE INVENTION 
The present invention relates generally to surgical instruments and more 
particularly to a disposable gingival grafting knife. 
Conventional gingival grafting methods require a scalpel and a unigraft 
knife or motor-driven mucotome to harvest a graft. Using a scalpel is 
excessively time consuming and often provides uneven graft width and 
thickness. Use of a unigraft knife or mucotome is expensive and carries a 
substantial risk of cross contamination. 
The invention solves or substantially reduces in critical importance 
problems with prior art instruments and methods by providing a disposable 
sterilizable gingival grafting knife which can be used to easily and 
effectively harvest a graft of uniform width and thickness and be 
discarded safely and cost effectively without risk of cross contamination. 
The invention comprises a narrow blade, sharpened on one side, formed to 
the desired shape of the graft and embedded into the end of a handle to 
define preselected width and thickness for the graft. A detachable tissue 
graft receptacle is attachable to the back of the knife near the blade for 
catching and holding the harvested graft. 
The invention is ideal for soft tissue grafts and is valuable to dentists, 
periodontists, oral surgeons and implantologists. 
It is therefore a principal object of the invention to provide an improved 
surgical knife. 
It is another object of the invention to provide a surgical instrument for 
harvesting a tissue graft of uniform width and thickness. 
It is a further object of the invention to provide a disposable periodontal 
knife. 
These and other objects of the invention will become apparent as a detailed 
description of representative embodiments proceeds. 
SUMMARY OF THE INVENTION 
In accordance with the foregoing principles and objects of the invention, a 
disposable gingival grafting knife is described which comprises a narrow 
blade sharpened on one side, formed to define a preselected 
cross-sectional shape of the graft and embedded into the end of a 
sterilizable handle to define preselected width and thickness for the 
graft, and a tissue graft receptacle removably attachable to the back of 
the knife near the blade for catching the harvested graft.

DETAILED DESCRIPTION 
Referring now to the drawings, FIG. 1 is a perspective view of grafting 
knife 10 representative of the invention, with tissue graft receptacle 11, 
discussed more fully below, attached to knife portion 13. FIG. 1a shows in 
perspective the blade end of knife 10 with receptacle 11 detached from 
knife portion 13. FIG. 2 shows a sectional view of assembled knife portion 
13 and receptacle 11 as viewed along line B--B of FIG. 1. Knife portion 13 
comprises handle 15 of suitable material formed into the configuration as 
shown, including first lengthwise portion 16 sized for ease of grasping by 
the user of knife 10, and second lengthwise portion 17 supporting blade 19 
embedded at distal end 20 of handle 15. Second portion 17 is disposed to 
first portion 16 at angle .beta. (about 120.degree. to 150.degree., 
preferably 135.degree.) preselected to facilitate harvesting a tissue 
graft as discussed below in relation to FIG. 3. Handle 1 comprise any 
suitable formable material sufficiently resistant to conventional 
sterilization (e.g., Chemiclave at about 270.degree. F. and 20-40 psi; 
Autoclave at about 250.degree. F. and 15-18 psi), as would occur to the 
skilled artisan guided by these teachings, such as acrylic or 
Plexiglas.TM.. In a model built in demonstration of the invention, handle 
15 was fabricated of light-cured acrylic and was about 4.5 inches in 
overall length and tapered over the length to a width of about 3/8 inch at 
end 20. 
Referring additionally to FIG. 2, blade 19 has sharpened edge 21 and the 
preselected shape suggested in the figures, with corresponding ends 23,24 
embedded into opposite sides of handle 15 at end 20. Blade 19 shape 
defines a preselected width w and spacing d between end 20 and central 
portion 25 of blade 19. In using knife 10 to harvest a tissue graft as 
discussed below, w and d define intended width and thickness of the graft; 
although graft size is not considered limiting of the invention, w usually 
is in the size range of about 5 to 9 mm and d usually is in the size range 
of about 1.0 to 1.5 mm for most periodontal, dermatologic, burn therapy or 
other type grafts. Blade 19 may be any suitable width (.about.2 mm in the 
demonstration model) and comprises any suitable material such as surgical 
steel, stainless steel, razor blade material or carbide steel, as is used 
conventionally for surgical instruments. 
Knife 10 may include optional cup-shaped tissue graft receptacle 11 
detachably mounted to second portion 17 near blade 19. Receptacle 11 is 
attachable to handle 15 by any suitable means such as a pair of tabs 31,32 
on opposite sides of handle 15 received by corresponding slots or tabs 
34,35 on opposite sides of receptacle 11. Receptacle 11 defines cavity 37 
for receiving a harvested graft and therefore prevents aspiration of the 
graft by a suction device used in conjunction with treatment of the 
patient or inadvertent swallowing of the graft by the patient, and 
minimizes the number of instruments needed for a harvesting procedure. 
FIG. 3 is a sketch of the palate of a patient 39 illustrating the 
convenient use of the invention to harvest a graft of palatal keratinized 
tissue and subjacent connective tissue. As suggested above, a graft of 
about 1.5 mm thickness may be normally taken. A scalpel (not shown) is 
first used to make a small incision 40 (1 cm or less in width) posteriorly 
away from the marginal tissue. Blade 19 of knife 10 is then inserted into 
incision 40 and drawn anteriorly for the desired graft 42 length. The 
harvested tissue graft 42 may then be approximated and sutured at a 
recipient site. Knife 10 may then be discarded. The invention was 
successfully tested to harvest free gingival grafts of uniform width and 
thickness from the palate of sheep bioheads for placement on the 
mandibular anterior teeth. The invention was also tested on a human 
patient to harvest a gingival graft (8 mm wide by 1.5 to 2.0 mm thick) 
from the palate for placement on the mandibular anterior teeth 23-25. 
The invention therefore provides a novel disposable grafting knife. It is 
understood that modifications to the invention may be made within the 
scope of the appended claims as might occur to one with skill in the field 
of the invention. All embodiments contemplated hereunder which achieve the 
objects of the invention have therefore not been shown in complete detail. 
Other embodiments may be developed without departing from the spirit of the 
invention or from the scope of the appended claims.