Initial experience of using GRAFTAC absorbable staples to attach split skin grafts

M. V. McKiernan, S. Pape and N. R. McLean

Department of Plastic, Reconstructive and Burns Surgery, Newcastle General Hospital, Newcastle upon Tyne, UK

The GRAFTAC skin stapler with absorbable tacs has been used to attach split-skin grafts in 28 patients, under a variety of clinical situations, and the outcomes studied. This knowledge has been reviewed in the light of our existing experience with the more familiar metal staple. Details of the patients and their conditions are presented, with two illustrative case histories, including one where both Graftac and metal staples were used. The relative costs were analysed and an attempt made to compare the cost-effectiveness of tacs and staples. A rationale for use of the more expensive GRAFTAC stapler is presented.

Introduction
The use of staples or clips is well established in surgery, with Michel clips in use for many decades. In traditional medicine the same principle is seen when soldier ants are used to close wounds with their powerful jaws, then the body is broken off to leave a natural 'clip'. The convenience of the modern disposable stapler is such that it is now a widely popular choice for affixing split-skin grafts, particularly where large areas are to be covered. Alternatives to the metal staple, such as tissue glue, or careful dressing without any fixative, are sometimes used, and their merits are well known. In this report we are confining our attention to those patients in whom it has been decided, for whatever reason, to use staples to attach a split-thickness graft.

The metal staple is not without its problems however. The staples are sometimes reported to be uncomfortable under the dressings, and cases of allergy requiring staple removal have been reported1. The major drawback centres around staple removal, where patients may suffer discomfort, some may even require general anaesthesia, and valuable staff time is consumed in the tedious task of locating and removing staples. This is not always successful and retained staples can be a source of later problems. (2)

In an effort to address these problems, we have used GRAFTAC absorbable staples on a trial basis, comparing them to our past experience of using metal staples.

Patients and materials
The Multifire GRAFTAC disposable stapler with Lactomer copolymer tacs is produced by Autosuture (all trademarks of United States Surgical Corporation, Autosuture UK, Ascot, Berks, UK). The device has been in use for approximately 3 years, and is due for introduction to the market in the UK in early 1995. It consists of a 'gun' - shaped body containing a spring-powered firing mechanism operated by squeezing a handle or trigger in a similar fashion to metal stapling devices. The tacs are delivered from the nose of the device where they are held in a disposable loading unit containing 35 tacs (Figure 1a,b). This unit may be replaced when empty, and extra units are available separately. The biomechanical performance of this device has recently been reviewed. (3) Up to three units may be used before the entire apparatus must be discarded.

Lactomer tacs are made of an absorbable synthetic polyester which is a copolymer of lactic and glycolic acids. It has been licensed for clinical use for over 10 years and is a component of other products such as sutures. The polymer degrades by hydrolysis, after which the glycolic and lactic acids are absorbed and metabolized. Absorption occurs initially as a loss of tensile strength, with 90 per cent lost within 21 days. This is followed by fragmentation of the tacs and complete absorption of the tac follows in subsequent weeks. Two types of tac are available: an 'S' tac (Figure Ic) and an 'X' tac. The 'S' tac is for routine use, while the 'X' type, which has more prominent barbs, is used in situations where extra hold is required (e.g. fat or muscle) or if excessive movement is anticipated. In this study no special criteria were necessary for inclusion, other than the patient having given informed consent and that one of the authors was available to perform the required surgery. Any patient with a condition requiring split-skin grafting was considered eligible unless the area involved was on the face or palms. Full-thickness graft cases were not included.

Information collected on each patient was entered directly onto a computerized database held on a Macintosh (Apple Computer Inc., Cupertino, CA, USA) laptop computer. As well as relevant demographic data, the extent of the area grafted, and the amount of GRAFTAC used were recorded along with details of appearances at dressing changes, and subjective evaluation of patient comfort and acceptability.

Figure 1. The disposable stapler unit is shown (a) with the cartridge detached showing how the unit may be reloaded. b, The unit is shown in use, held perpendicular to the plane of the skin and with the nose resting on the graft. c, A close-up view of an 'S'-type tac is shown with the retaining grooves on the legs dearly seen. In the 'X'-type, more prominent barbs project towards the midline from the legs to give a more secure hold.

Case reports

Case 1
A 44-year old female patient was admitted with 40 per cent body surface area deep-dermal and full-thickness flame bums. Following resuscitation, she underwent excision and grafting of the burned areas, requiring a total of four episodes of skin grafting. On the first two occasions metal staples were used to retain both meshed split-skin grafts and also Biobrane, which was used to cover areas debrided for which no skin was available due to limited donor sites. The staples applied at the initial operation were removed under general anaesthesia at the second operation, however those from this second procedure were removed on the bums unit. Despite the routine application of local anaesthetic cream (EMLA, Astra Pharmaceuticals Ltd, Kings Langley, Herts, UK), the patient complained of significant discomfort during the proceedings which lasted over 30 min and required supplementary analgesia (Entonox).

After the donor sites had healed further grafting was under taken on two occasions to obtain full cover. On both these occasions, GRAFTAC was used to hold the grafts in position (the patient is shown in Figure ib). The tacs extruded spontaneously and were removed with the first (5 days) dressing on both occasions. The patient suffered no discomfort attributable to the tacs and expressed her distinct preference for GRAFTAC over metal staples.

Case 2
An 83-year-old lady was referred with a 3-week-old haematoma of her left leg following minor trauma. The overlying skin was by this time necrotic and sloughing and was debrided gently in the dressing unit, leaving a 20 x 10cm defect (Figure 2).

Discussion

The evaluation of a novel product such as GRAFTAC necessarily includes consideration of several factors. Fore most, among these must be an assessment of how well, if at all, the product achieves the purpose for which it is intended. However, in the present circumstances of health service-spending containment, the absolute cost and also the value for money are of considerable, perhaps equal, importance. Once these parameters have been addressed, we may also consider aspects of biomechanics, ergonomics and aesthetics.

In this study GRAFTAC performed without fault in retaining grafts in position until the first change of dressing. Up to this point, GRAFTAC is on a par with traditional metal staples. As most tacs extruded spontaneously, the majority at the first dressing, and the remainder were removed easily, we have not observed at first hand GRAFTAC's absorbability. In the light of the high first dressing extrusion rate, it may be of minor importance in any case. This feature of spontaneous extrusion gives GRAFTAC an advantage over metal staples in reducing the amount of time spent on dressings. In cases where it is felt necessary to use this form of graft retention, GRAF TAC also scores on patient comfort, with a high degree of patient acceptability in all cases. While no attempt at formal measurement of pain or discomfort was undertaken in this study, both patients who had experience of GRAFTAC and metal staples stated an unqualified preference for GRAFTAC.

On the question of cost there are certain difficulties in evaluating GRAFTAC. At the time of conducting this study, GRAFTAC is available only on a named-patient basis, and imported through Auto Suture Company UK in limited quantities from the USA. Thus, the unit cost of 35 tacs is approximately three times that of a disposable unit with an identical number of metal staples, though additional GRAFTAC cartridges for reloading cost 70 per cent of a complete unit. It is to be expected, however, that if the product is licensed and becomes available in bulk, the price will decrease accordingly. Added to the equation is the difficulty in accurately measuring and costing the savings in time gained by obviating the need for formal removal of staples, as well as savings in instrument provision and maintenance costs. In our unit it is established practice to apply local anaesthetic cream (EMLA) to staple sites before removal to reduce discomfort. While apparently effective, this adds approximately 30 per cent to the basic cost of 35 metal staples. All these factors combine to narrow the gap in raw cost between GRAFTAC and metal staples.

In terms of cost-effectiveness and value for money, it is difficult to pronounce on GRAFTAC in isolation or in comparison to metal staples. GRAFTAC offers a unique solution to the task of graft fixation, which it performs effectively. By comparison, metal staples also perform the same basic function, with a lower basic cost, some not insignificant (though variable) extra monetary costs and the unquantifiable added price of some patients' discomfort.

It seems clear at this point that there is a role for GRAFTAC under present circumstances in the treatment of patients having large areas grafted where it becomes increasingly economical, for patients who are so anxious or of such an age that a general anaesthetic would be required for staple removal, or those patients who are unusually sensitive to pain and discomfort in whom it is more humane.

References

• 1 Oakley AM, lye FA, Carr MM, Skin clips are contraindicated when there is nickel allergy. JR Soc Med 1957; 80: 290291.
• 2 Pape SA, Hodgkinson P. Retained skin staple (letter), Burns 1994; 20: 281.
• 3 Himel HN, Bill TJ, Bentrem DJ ef al. Biomechanical perform

Paper accepted after revision 27 January 1995.