Automatic disposable stapling devices for wound closure

ORIGINAL CONTRIBUTION

Automatic Disposable Stapling Devices for

Wound Closure

Alan Johnson, MD George 7:. Rodeheaver, PhD

Linda S. Durand, MD Milton T. Edgerton, MD

Richard F. Edlich, MD, PhD Charlottesville, Virginia

Specially designed automatic disposable staplers are proving to have an important role in wound closure. Staple closure is accomplished with significant- ly less damage to the wound defenses than with the least reactive suture. A comprehensive evaluation of the mechanical performance of the commercially available staplers demonstrates that the Premium TM stapler is superior to the other staplers. Johnson A, Rodeheaver GT, Durand LS, Edgerton MT, Edlich RF: Automatic disposable stapling devices for wound closure. Ann Emerg Med 10:631- 635, December 1981. staplers, for wound closure; wound closure, staplers

INTRODUCTION

Several different methods have been devised to close wounds in the emergency department. Suturing the wound edges is the most popular. Specially designed surgical tape, a more recent innovation, is proving to have an important role in the closure of skin wounds. Metal staples, the latest development in the field of skin closure, are becoming an integral part of the physician's armament- arium.

It is the purpose of this article to examine the effect of the closure techniques on the incidence of infection and to compare the mechanical performance of the commercially available disposable staplers.

MATERIALS AND METHODS Mechanical Performance

A variety of disposable staplers are now commercially available for use in surgery. These staplers include Premium TM (United States Surgical Corporation, Norwalk, CT), Precise TM (3M Center, St. Paul, MN), and Proximate TM (Ethicon, Inc, Somerville, NJ). The mode of operation of each stapler is to create an incom- plete rectangular staple that has three components. First, the ~'cross member," or exposed portion, of the staple lies parallel to the skin surface and is perpendicular to the wound. Second, the '~legs" of the staple extend into the skin and comprise the height of the rectangle. Finally, the pointed tips form the fourth

"side of the rectangle and lie beneath the skin parallel to the cross member. The performance of these staplers was judged by the following parameters: handling

From the Emergency Medical Service and the Department of Plastic Surgery, University of Virginia Medical Center, Charlottesville, Virginia. Presented at the University Association for Emergency Medicine Annual Meeting in San Anto- nio, Texas, April 1981. Address for reprints: Richard R Edlich, MD, PhD, Emergency Medical Service, University of Virginia Medical Center, Charlottesville, Virginia 22908.

10:12 (December) 1981 Ann Emerg Med 631/25

characteristics, ease of positioning stapler, maximal angle for visual access to staple, precocking mechanism, staple release mechanism, angle at which staple is delivered, and quality assurance.

Resistance to Infection

The exper imental model previously reported z has proven reliable and r ep r oduc ib l e in d a y - t o - d a y assessment in our experience. The s tandard ized p r e p a r a t i o n of the animal, the technique of wounding, and the bacterial culture procedure have previously been reported. 1 Two standardized incisions, parallel and equidistant from the vertebral col- umn, were made in each guinea pig. The incisions measured 3 cm in length and extended through the panniculus carnosus. Any bleeding that occurred was stopped by gentle pressure applied by gauze sponges.

Ninety-six animals were randomly divided into four t reatment groups. The wounds in designated groups received 0.02 ml of 0.9% sodium chloride containing 104, 105, 106 or 107 Staphylococcus aureus (No. 12,600 American Type Culture Collection Center, Rockville, MD). After contamination, the animals were subdivided randomly into treat- ment groups that were subjected to different closure techniques. One group of wounds was approximated with the least reactive nonabsorbable suture, 4-0 monofilament nylon. Four interrupted sutures, placed 2.5 mm from the wound edges, were used to approximate the wound. Each suture was tied carefully to ensure that the tissue within the tied suture loop was not subjected to excessive ten- sion. Wounds in another group were closed with reinforced microporous tapes (Reinforced Steri-strips T M , 3M Center, St. Paul, MN).

In the last group, wounds were closed with four regular-size surgical staples using the Premium TM stapler. After closure, the backs of the animals were bandaged and they were caged and fed ad libitum.

On the fourth postoperative day, the animals were sacrificed and the in f l ammato ry responses of the i r wounds assessed. The wounds were opened and inspected for evidence of purulent exudate. In all groups, an estimate of the number of viable bac- ter ia in the wound was made by swabbing the length of the wound with a sterile, cotton-tipped applicator and then determining the bacterial count on the applicator using

Table 1 PERFORMANCE OF STAPLERS

Parameters Proximate TM Premium TM Precise TM

Handling Desk Pistol Pickups characteristics stapler grip (forceps)

Maximal angle 45 ° 85 ° 75 ° of visual access

Angle at which 90 ° 60 ° 45 ° staple enters tissue

Ease of Surgeon Swivel Surgeon positioning dependent nose dependent

Precocking No Yes Yes mechanism

Quality Repair, refund 2 for 1 Repair, refund assurance or replace replacement or replace

standard bacteriologic techniques. 2 The results are reported as the aver- age logarithm of the bacterial count, as this more accurately reflects the logarithmic growth of the organism.

All results were subjected to sta- t i s t ical ana lys is u t i l iz ing a 95% confidence in te rva l as a criterion of significance. Infection rates be- tween different t rea tment groups were compared using a hypergeomet- ric distribution test. The logarithmic values of the estimates of the wound bacterial counts were compared using a Student's t-test.

RESULTS Mechanical Performance

The physician's selection of a disposable stapler is usually determined by its performance (Table 1). One of the most impor t an t per formance criteria is handling characteristics. The Proximate TM stapler functions much like a desk stapler (Figure 1A). The Premium TM stapler has movable and fixed handles that are operated in a manner similar to that of the Proximate TM stapler (Figure 1B). In both cases, the physician's index, long, ring, and small fingers compress the movable handle of the stapler against its fixed handle, which is stabilized by the palm of the hand. This motion can be repeated without fatigue.

The design of the Precise TM stapler is similar to that of surgical pickups, but is handled in a slightly different way (Figure 1C). While the two movable handles of the surgical pickups can easily be compressed be-

tween the physician's thumb and index finger, compression of the two movable handles of the Precise TM stapler requires considerably more force using the thumb, index, long, and ring fingers. When physicians re- peatedly compress the two movable handles of the Precise~M stapler, they often complain that their hands tire.

Ideally, the device should be designed so that the physician can view the staple during its formation. In this study, the maximal angle of visual access to the staple was measured at the range of positions from which the eye could see the staple as it was formed when the tip of the stapler was held to the surface of the skin. The Premium" stapler has a long (5 cm), narrow (8 mm) cartridge that permits an excellent view of the staple. The maximal angle of visual access to the Premium TM staple is very wide (85~°). The Precise TM stapler also permits excellent visibility of its staple, with the physician's line of sight (75 °) partially obstructed by its staple magazine. The Proximate" ' stapler offers the poorest visualiza- tion at the end of the stapler (45°).

In the Premium TM and Proxi- mate TM staplers, the staple is dis- pensed at the delivery end of the cartridge that is touching the surface of the skin. The Proximate TM stapler de- livers its staple perpendicular to the wound, with the cross member often flush with the skin surface. Such a deeply implanted staple may induce several damaging effects on the tissue. First, it can strangulate the entrapped tissue, and thereby reduce its resistance to infection. Second, it

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can abrade the unde r ly ing skin, which may resul t in p e r m a n e n t transverse scars (~cross-hatching") that are unnecessary reminders of the accident. This troublesome prob- lem has been obviated by the Pre- mium TM and Precise TM staplers by changing the angle at which the staple is delivered to the skin surface. The Premium TM stapler implants the staple at approximately a 60 ° angle to the skin surface. After the staple is formed at this angle, it tends to ~ssume an upright position that is perpendicular to that of the surface of the skin. As the staple rotates from 60 ° to 90 °, it leaves a space be- tween the skin surface and its cross member. This additional space allows the entrapped tissue to expand during healing without coming in con- tact with the cross member.

The Precise TM staples are delivered at a 45 ° angle to the skin surface from a recessed portion of the stapler that is anterior to and above the end of the stapler that contacts the skin surface. When delivering a staple from the Precise TM stapler, it is particularly important to evert the edges of the skin into the recessed portion of the stapler. If the wound edges do not enter this recessed part, the staple may not engage enough tissue to permit wound closure.

The configuration of the stapler should allow the position of its cartridge to be adjusted manual ly to facilitate placement of the staple. The rotating swivel nose staple cartridge of the Premium TM stapler ro- ta tes 360 °, thus al lowing reposi- t ioning of the tip of the stapler. Adjustment of the position of the cartridge is especially helpful when stapling recessed anatomic sites, such as the axilla, web spaces of the hand, or the perineum. Because the Proxi- mate TM and Precise TM staplers do not have a swivel nose, positioning the stapler is dependent on the physician's dexterity within the limits afforded by the geometry of the in- strument.

An important additional feature of the Premium TM and Precise TM staplers is their precocking mechanism, which allows the physician to hold the staple securely during its formation. A clutch-like mechanism has been incorporated into these staplers to allow the surgeon to release pressure on the stapler handles without losing control of the partially formed staple. The exposed ends of partially formed staples are strong enough to be used as skin hooks which facilitate approximat ion of the wound Fig. 1. A. Proximate TM stapler. B. Premium TM stapler. C. Precise TM stapler.


edge. The Proximate TM stapler does not have this precocking mechanism, thus limiting the physician's control of the staple during its formation. If the physician does not maintain con- tinuous pressure on the handles of the Proximate TM stapler during the formation of the staple, the staple may slip off the anvil before formation.

All s tapl ing devices employ a similar mechanism for forming the staple. Each stapler contains a car- t r idge of i n d i v i d u a l s t ap les . By squeezing the movable stapler handle(s), a plunger advances one staple against an anvil. As the staple is pressed against the anvil, it assumes a rectangular configuration with its sharp ends penetrating the skin. The mechanism by which the staple sepa- rates from the anvil varies with the individual stapler. The ejector spring of the Premium TM stapler releases the staple away from the anvil foot auto- matically. The Precise TM and Proxi- mate TM staplers require the physician to remove physically the anvil beneath the formed staple. In the case of the Precise TM stapler, the stapler is moved forward; the Proximate TM stapler mus t be moved backward to d isengage the s tapler . When the Precise TM and Proximate TM staplers are used in the same hospital, this difference may be confusing.

The design of the staple may be an important consideration. Interest- ingly, the size of the regular and wide s taples for the P rox imate TM,

Premium TM, and Precise TM staplers differ considerably (Table 2). The legs of some s tap les are cons iderab ly longer than others, which may more adequately accommodate the swollen wound edges dur ing healing. The advantages of one configuration over another are, however, theoretical , and this subject wa r r an t s fur ther study. The sharpness of the ends o~ staples mus t also be examined in further studies.

The manufacturers of the Pre- cise TM and Proximate TM staplers have confidence in their products and are prepared to repair, refund, or replace their instruments. In the event that the Premium TM stapler misfires, two instruments will be replaced for each that malfunctions.

Resistance to Infection Wounds closed by tape exhibited

the highest degree of resistance to infection, followed by the stapled wounds and then the wounds approximated by sutures (Figure 2). The su-

Table 2 DESIGN OF STAPLES

Size Regular

Proximate TM

Premium TM

Precise TM

Label Measured Width/Height Width/Height

(mm) (mm)

5.7/3.9 5.4/3.7 4.8/3.4 4.9/3.5 5.0/3.5 5.1/3.4

Wide ProximateTM 6.9/3.9 6.9/3.6 Premium TM 6.5/4.7 6.5/4.7 Precise TM 7.5/4.2 7.6/4.1

periority of tape closure was evident at all levels of the contamination ex- cept 5 x 107, at which all wounds were destined to develop infection re- gardless of the closure technique. In the presence of lower bacterial inocu- la, wounds approximated by the stapler exhibited a lower rate of infec- t ion than did those closed by the least reactive nonabsorbable suture, monofilament nylon.

The infection ra tes of wounds were c o r r e l a t e d wi th the wound bacterial counts (Figure 3). Sutured wounds exhibited the highest bacterial counts, followed by the stapled wounds and then the taped wounds. When the infection rates of wounds reached 100%, the bacterial counts of the wounds did not differ signifi- cantly.

DISCUSSION The use of clips first appeared in

ancient Hindu medicine. Insect man- dibles were used to th is end for wound closure and are still being em- ployed today for wound closure in the jungles of southern Bhutan at the foot of the Himalayas. 3 Mechanical s u t u r i n g p robab ly was g iven i ts g rea tes t impetus by the Russians and was introduced and championed in the Uni ted States by Ravitch. 4 With the advent of disposable automatic staplers, staples have become an important closure technique for the modern physician.

Stapling is the fastest method of closure of long l inear skin lacerations. 5 Wound closure with a stapler is accomplished with considerably less damage to the wound defenses than is closure with the least reac- t ive nonabsorbab le suture . These benefits must be weighed against the technical superiority of sutures for

wound closure. Surgical suture re- mains the best technique for metic- u lous reapproxif i~at ion of wound edges. Consequently, staple closure of lacerations in the emergency department should be reserved for patients wi th l inea r nonfacia l l acera t ions caused by shear forces (ie, knives). I t is p a r t i c u l a r l y sui ted to long, straight lacerations of an extremity, trunk, or scalp in a critically ill pa- t ient . Closure of scalp lacerat ions with staples should be performed after computer tomography to elimi- nate the occurrence of artifacts pro- duced by the staples. 6

Stapling is a psychomotor skill that requires practice. The physician mus t place each staple so tha t it approximates the wound edges without strangulating the tissue within the formed staple. When closing skin wounds with staples, it is advisable to evert the skin edges before they are secured with the staple. The ease with which the physician can staple the wound ~s i n f l uenced by the mechanical performance of the stapler.

We favor the Premium TM stapler over the other instruments for skin wound closure. This stapler has been specially designed to permi t max- i m u m visua l iza t ion of the wound edges as well as the staple during its formation. Its long, narrow swivel cartr idge tha t can be rotated 360 ° facilitates positioning of the stapler. It inserts the staple into the skin in a manner that allows the cross member of the staple to be above the skin surface. This addit ional space be- tween the cross m e m b e r and the underlying skin may be filled with the edematous skin edges during the early postoperative period without t h rea t of s t rangula t ion of the en-

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t rapped tissue. In addit ion, the Pre- m i u m TM s t a p l e r h a s a p r e c o c k i n g mechanism tha t allows the phys ic ian to hold the s taple securely dur ing its format ion . A n o t h e r un ique advan- tage of the P remium TM s tapler is i ts ejector spr ing tha t au tomat ica l ly releases the staple. Final ly , the han- d l ing cha rac t e r i s t i c s of the s t ap l e r are such tha t the physic ian can easily implan t a large number of s taples without becoming fatigued.

Staples should be removed from the skin before the e ighth day following wound closure us ing special ly de- s igned s t ap l e removers . S t ap le re- moval is in i t i a ted by s l iding the t ips of the double lower jaws of the s taple remover f i rmly under the staple. The handle a t tached to this lower j aw is then lifted up s l ight ly wi th the fingers before the other jaw compresses the staple, thus wi thdrawing the end of the s taple from the skin. This lift- ing away from the skin reduces any p r e s s u r e on the sens i t ive , p a i n f u l under ly ing wound. The process is repeated unt i l al l s taples are removed, after which the skin edges are reinforced by tape.

SUMMARY

The au tomat ic disposable s tap ler is a recent innovat ion tha t is proving to have an impor tan t role in the closure of skin wounds. S tap l ing is the f a s t e s t m e t h o d of c losu re of long, l i n e a r l a c e r a t i o n s . W o u n d c losure w i th s t a p l e s is a l so a c c o m p l i s h e d with considerably less damage to the wound defenses t han is closure wi th the leas t react ive nonabsorbable suture. A comprehensive examina t ion of the m e c h a n i c a l p e r f o r m a n c e of commercial ly ava i lab le s taplers demonstrates t ha t the P remium TM s tapler is superior to the other devices.

REFERENCES

1. Edlich RF, Tsung MS, Rogers W, et al: Studies in the management of the contaminated wound. I. Technique of closure of such wounds together with a note on a reproducible model. J Surg Res 8:585- 592, 1968. 2. Edlich RF, Madden JE, Prusak M, et al: Studies in the management of the contaminated wound. VI. The therapeutic value of gentle scrubbing in prolonging the limited period of effectiveness of anti- biotics in contaminated wounds. Am J Surg 121:668-672, 1971. 3. Majno G: The Healing Hand, Man and Wound in the Ancient World. Cambridge, Harvard University Press, 1977, p 14. 4. Steichen FM, Ravitch M: Mechanical sutures in surgery. Br J Surg 60:191-196, 1973.

INFECTION RATE m u / : $

8 0 - H STAPLE ~ / /

~ 60-

W ~: 40-

U') CO m o 20-

10 4 10 5 I0 6 I0-: I0 s

INOCULUM (S. aureus)

Fig. 2. The resistance of taped wounds to infection was the greatest, followed by the stapled wounds and then the sutured wounds.

o 6.o- r

.._J < E: 4.5- W I'- (.9 <m 5.0- m ._1

~ 1.5- >

BACTERIAL GROWTH

SUTURE STAPLE TAPE

• tJ I I I I !

i0 # 10 5 10 6 10 7 I0 8

INOCULUM (S.eureus)

Fig . 3. The bacterial counts of sutured wounds were the highest, followed by the stapled wounds. The taped wounds had the lowest bacterial counts.

5. Lennihan R Jr, Mackereth MA: A com- parison of staples and nylon closure in varicose vein surgery. Vasc Surg 9:200- 203, 1975.

6. Von Hoist H, Bergstrom M, MSller A, et al: Titanium clips in neurosurgery for e l imina t ion of ar t i fac ts in computer tomography (CT). Acta Neurochir 38:101- 109, 1977.


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Automatic disposable stapling devices for wound closure