Traditional tie-over dressing is the most frequently used method for free-skin grafting.1,2 It is compatible in many clinical situations. Nonetheless, the suture threads that are located at the edges of a wound can result in raised edges of the grafted skin, like a crater rim.3 More seriously, complications can arise, such as necrosis, effusion or haemorrhage of the local skin.4 These shortcomings may affect the survival and appearance of the grafted skin. This traditional method is not appropriate for some complicated circumstances with high requirements in plastic and hand surgery, for example where there is a need for flexibility. This report introduces a modified tie-over dressing technique—extra-wound fixation—which was successfully performed in patients with skin defects.
Methods
Patients
In this observational cross-sectional study, the medical records of individuals who had been patients between January 2012 and December 2017 were retrospectively analysed. Patients were divided equally into two groups:
- Patients treated using the extra-wound fixation technique
- Patients randomly selected from those who were treated using the traditional tie-over method.
A sample of 38 patients was considered sufficient to compare differences at a 95% confidence level (CI) (p<0.05). The patients were screened using the same inclusion and exclusion criteria, Inclusion criteria was patients who had signed the informed consent, did not smoke, did not have diabetes type 2, had no history of cardiocerebrovascular diseases, and who had a body mass index (BMI) <30kg/m2. Patients were excluded if they did not sign the informed consent, smoked, or had diabetes type 2, had peripheral arterial disease or end-stage renal disease, patients >60 years of age, or who had local or systemic infections.
Ethical approval
The study was approved by the Medical Ethics Committee, Shandong Provincial Hospital Affiliated to Shandong University. Signed informed consent, including for the use of photographs, was obtained from all patients.
Preparation of the recipient donor site
Necrotic tissue in the wound was carefully removed to avoid exposure of the bone and tendon. Gauze soaked in warm saline or adrenaline (1:50–1:200000 dilution if necessary) was used for compression haemostasis. Large petechial haemorrhage was interrupted by bipolar electrocautery, which is commonly used in neurosurgery.
Preparation of full-thickness skin graft
Shape- and size-matched skin grafts were collected from the groin area. In accordance with the traditional tie-over dressing method, the full-thickness skin graft, including some fat was harvested by blade, which was then defatted using scissors. The grafted skin was sutured peripherally to the wound. After the grafted skin pieces were sutured, multiple slits were made in the skin to prevent fluid collection under the skin graft. The undersurface of the grafted skin was washed with hydrogen peroxide and saline to remove haematoma, if necessary. The grafted skin and wound edges were closed using interrupted suturing techniques.
Packing method in the extra-wound tie-over technique
Unlike the traditional method, a second stitch to pack the grafted skin was placed 0.5–1.0cm lateral of the wound edge. The stitches were made through healthy skin, and a long suture thread was reserved for future packing (Fig 1). Wound packing and dressing were then performed in the standard way as the traditional tie-over dressing method (Fig 1 and 2).
Postoperative care
All patients were treated to prevent infection. On postoperative days 10–12, the dressing was removed. The wound was observed for any loose sutures, malodour, effusion or oedema in the grafted area. Particular attention was paid to identifying any blood circulatory disorders and nerve compression symptoms. During a six-month follow-up, the colour and texture of the grafted skin, especially the skin edges, were observed and recorded.
Statistical analysis
Chi-square test was used to detect significant differences in the incidence of outcome variables between the extra-method fixation technique group and the traditional tie-over method group. For all tests, statistical differences were determined to be significant at p<0.05.
Results
The medical records of 38 patients (30 male and eight female patients) aged 15–38 years (mean=25.4 years)were retrospectively analysed. Of these, 19 (50.0%) patients were treated using the extra-wound fixation technique, and the remaining 19 (50.0%) were randomly selected from patients treated using the traditional method.
Patients in the extra wound fixation group had a total of 21 skin defects, with sizes ranging from 1.5×3.0cm to 15×20cm. Of these patients, 10 had skin defects on their hands, seven had feet skin defects, and two had skin defects on the scalp after avulsion injury. Granulation tissues had formed in 14 patients, and five patients had fresh trauma.
Patients in the traditional tie-over method group had a total of 23 skin defects, with sizes ranging from 1.0×2.0cm to 17×22cm. There were 13 hand defects, five foot defects and one scalp defect after avulsion. Granulation tissue had formed in 12 patients and seven patients had fresh trauma.
Patients in both groups were first examined on postoperative days 10–12 during hospitalisation and attended a post-discharge follow-up visit within 1–6 months (average 2.8 months). The examination was performed by doctors who did not perform the surgery. The outcome variable of ‘no laceration’ was collected at the time of the surgery. The variables of ‘no crater rim-like appearance’ and ‘good survival of grafted skin’ were examined at the time of removal of the dressing during hospitalisation. The transplantation was considered to be successful when >90% of the grafted surface area was stable, which was defined as ‘good survival of grafted skin’.5 The remaining variables were followed up at the outpatient clinic after discharge (Table 1).
Table 1. Follow-up outcome variables of the extra-wound fixation group compared with the traditional method group using the Chi-square test
| Outcome variables | Extra-wound fixation group (n=19), n (%) | Traditional method group (n=19), n (%) | p-value (two-sided) |
|---|---|---|---|
| No laceration | 19 (100.0) | 10 (52.6) | 0.001 |
| No crater rim-like appearance | 19 (100.0) | 13 (68.4) | 0.020 |
| Good survival of grafted skin | 19 (100.0) | 12 (63.2) | 0.008 |
| Normal colour (no obvious hyperpigmentation) | 11 (57.9) | 12 (63.2) | 1.000 |
| Soft texture | 12 (63.2) | 10 (52.6) | 0.743 |
| No scar contraction | 14 (73.7) | 9 (47.4) | 0.184 |
| Well-shaped grafts without swelling | 13 (68.4) | 9 (47.4) | 0.325 |
| The skin elasticity (prolonged postoperative observation) | 15 (78.9) | 11 (57.9) | 0.295 |
| Good level of sensation of limbs/fingers recovered and the two-point discrimination* | 13 (68.4) | 10 (52.6) | 0.508 |
The grafted skin healed well, without obvious infection or necrosis, regardless of the site, shape and area of the skin defects (Fig 1 and 3). The grafted skin (21 pieces in 19 patients) in the extra-wound fixation group was close to normal in colour and appeared to be smooth (Fig 3c). No crater rim-like appearance in the central area or edges of the grafted skin was observed in any of the patients. Further postoperative visits at six months showed that the texture of the skin grafts had softened, with a thin underlying layer of adipose tissue. Skin elasticity improved gradually with regeneration of dermo-elastic fibre.
Nominal scale surveys were then conducted with patients (Table 1). Compared with patients in the traditional method group, significant improvements in ‘no laceration’ (p=0.001, Fisher's exact test), ‘no crater rim-like appearance’ (p=0.020, Fisher's exact test) and ‘good survival of grafted skin’ (p=0.008, Fisher's exact test) were observed in patients who were treated using the extra-wound fixation technique.
Discussion
The traditional tie-over dressing is widely used for skin grafting in the field of trauma, burns, and plastic surgery.6 Complete haemostasis and tight-fitting grafted skin to the recipient donor site are essential in the use of split-thickness or full-thickness skin grafts,7 which could prevent haematoma. Unlike flaps, skin grafts do not have their own blood supply, so they must rely on a well-vascularised wound bed for graft in-growth. If there were haematoma and space due to incomplete haemostasis and tight-fitting grafted skin to the recipient wound bed, the vascularisation process of the grafted skin would be delayed or go to failure. Survival of a skin graft on its recipient site relies not only on a clean and well-vascularised bed but also on adequate immobilisation with no infection, haematoma, or serous collection beneath the graft.6,8,9 However, irregular shaped wounds may be a challenge for tight-fitting grafts as there may be more gaps and corners during the tie-over dressing, which inevitably results in difficulty in packing. Moreover, it should be noted that the traditional tie-over dressing is incompatible with irregular wounds due to the difficulty of packing.6
Effective skin grafting aims not only to cover the wound, but also to restore the appearance and function of recipient donor sites. The traditional tie-over dressing method is applied to close and provide forced pressure to the grafted skin in order to get the skin graft to take. However, it may cause skin grafts to develop a crater rim-like appearance (Fig 2a). Necrosis and infection may also occur at the edges of the ‘crater’, leading to the failure of grafting.6,10 Moreover, the tissues and skin of the recipient donor site, especially for granulation tissues, can become brittle and unhealthy (Fig 1a–b).11 These conditions may increase the chances of laceration by suture threads and result in the failure of packing. Finally, during traditional tie-over dressing, the peripheral tension of the grafted skin is higher than the central tension in the recipient donor site, which cause the grafted skin to develop a low-lying centre, making the recipient donor site area uneven.3,11
Ever since the introduction of the traditional tie-over dressing method, various modifications have been attempted. For example, using rubber band buckles is applicable for flexible dressings and repacking.512 With multiple loop silk threads, it is feasible to frequently monitor the status of grafted skin.69 A bra hook or jacket clip enables surgeons to perform repeated tie-over dressings.13,14 For the purpose of time-saving and to enable single-surgeon surgery, the skin stapler and barbed suture tie-over dressing techniques were developed.15,16,17 In cases of deep skin defects, a silicone tube for additional pressure on the edges of skin grafts is used.18 In order to prevent infection, hydrogel-impregnated dressings or octenidine have been employed in some studies,4,19 and the negative pressure wound therapy technique was developed to enhance the skin graft survival rate.20,21
With the traditional tie-over method, it can be difficult to resolve some intractable wounds, such as irregular wounds and brittle wound edges, which can result in an unsatisfactory appearance. Though there are many modifications to the tie-over dressing, these tend to focus on the surgical tools and packing materials. In this study, we aimed to explore how these intractable wounds can be more effectively managed using our modified technique.
Considering the disadvantages of the traditional tie-over dressing method, we designed the extra-wound fixation method, which has been successfully applied with satisfactory outcomes in our clinical practice. In this modified method, a second interrupted stitch was made through healthy skin 0.5–1cm lateral to the edge of the grafts. A long suture thread was retained at the additional stitches and was used for dressing and fixing. The key improvement in the method involves changing the dressing and fixing points from unsteady wound edges to peripheral healthy skin. In this way, the extra-wound fixation technique is also less likely to cause a crater rim-like appearance (Fig 1, 2b, 2c and 3). Another advantage is that the dressing and fixing points are distant from the wound edges and can be easily arranged in a regular shape to be compatible with irregular wounds (Fig 1e–h). Moreover, the modification introduces uniform pressure between the grafted skin and wound recipient donor site. This in turn reduces the incidence of necrosis and infection in the ‘crater’ rim. Finally, the skin around the recipient donor site is usually brittle and unhealthy, and this modified method could prevent shearing forces from disrupting the wound bed edge due to a move in the dressing contact points to healthy skin and away from the wound edge.
Limitations
It should be noted that the traditional tie-over method still plays a major role in skin grafting. This study details the minor modfication we have made to this technique. A limitation of this study is that the number of cases is small and therefore more work needs to be done to confirm the effectiveness of the modification. For example, there are no biochemical markers to compare inflammation and other indicators. Furthermore, it is not clear whether it could cause new scars or injuries on healthy skin.
Conclusion
The extra-wound fixation technique can be applied to different skin grafts such as in cases of unhealthy and irregular wound repair. It could improve the survival of grafted skin, reduce the risk of laceration, and eliminate the crater rim-like appearance. This technique is a modification of the traditional tie-over dressing method, which offers an alternative for the repair of intractable wounds. Further clinical studies are needed to evaluate the postoperative outcomes in more patients.
Reflective questions
- What is the key surgical operation using the extra-wound fixation technique?
- Which types of wounds and skin grafts are most suitable to adopt the extra-wound fixation technique?
- What are the advantages/disadvantages of using the extra-wound fixation technique compared with traditional tie-over dressing method?