Comparing Skin Grafts Harvested From Wrist With Those Harvested From Groin Region in Patients With Fingertip Injury: A Randomized Clinical Trial

Namazi, Hamid; Sharifzadeh, Reza; Eskandari Sani, Behdad; Mokarami, Farzam

doi:10.17795/soj-446

Hamid Namazi

¹, Reza Sharifzadeh²

, Behdad Eskandari Sani¹

, Farzam Mokarami²

1- Bone and Joint Disease Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran
2- Department of Orthopedic Surgery, Imam Reza Hospital, AJA University of Medical Sciences, Tehran, IR Iran

Keywords: Skin Grafting, Fingertip, Donor Site, Skin

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Abstract

Patients and Methods: A total of 72 patients in need of skin grafting were randomized to two group of 36 to receive skin graft harvested from the wrist or from the groin regions. The patients included 71 males and only one female patient who was in the wrist harvested group. All the patients were operated by one technique. The minimum follow-up period was 18 months. The grafted skin was evaluated clinically regarding two-point discrimination (TPD), light touch, ulcer, graft contracture, hair growth on the grafted skin, and color difference between the graft and recipient site, which was evaluated with photo analyzer in Photoshop software.

Copyright © 2015, Iran University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.

1. Background

Fingertip injuries are among the most prevalent hand injuries and immediate management of these injuries is imperative (1, 2). When skin loss is more than half of the pulp size, coverage with skin graft leads to faster recovery with less morbidity (1). Full-thickness skin grafts supply better protection and sensation as well as less contracture than split thickness skin graft does (1, 3-5). The goal is performing full thickness skin graft from inconspicuous donor sites that provide an excellent clinical and photographic match in terms of color, texture, thickness, and sebaceous quality. Yet, there is no study concerning the clinical difference among these skin grafts outcomes.

2. Objectives

3. Patients and Methods

This multicenter randomized clinical trial was conducted in accordance with the ethical principles of Helsinki Declaration and was approved by the Ethical Committee of Shiraz University of Medical Sciences (Project No, ct.p.91.2611; IRCT registration ID, IRCT2014110413259N1. All the patients or their guardians signed the written informed consent of the study procedure. All of the operations were done from August 2011 to April 2012 in two medical centers; Nemazee Hospital, Shiraz, Iran, and Imam Reza Hospital, Tehran, Iran, with a minimum follow-up period of 18 months.

3.1. Patients’ Eligibility

A total of 72 patients with acute traumatic fingertip injuries requiring skin grafts were evaluated for eligibility. The eligibility criteria were as follows: aging 20 to70 years, normal sensation and judgment, being nonsmoker, no neuropathic disorders including diabetes, autoimmune diseases (e.g. scleroderma), congestive heart failure, chronic liver diseases, chronic renal failure, and peripheral vascular diseases.

3.2. Sample Size and Randomization

Considering 40% difference in variables, power of 80%, and α of 0.05, sample size of at least 36 patients was calculated according to the previous studies (6). In order to increase the study power and reproducibility, we enrolled 72 eligible patients with fingertip full-thickness skin injuries and randomly allocated them to two groups of 36, ie, wrist group and groin group, by Research Randomizer Program (7). All patients had fingertip skin loss of more than 50% of the pulp area at index, middle, or ring fingers (Table 1).

Table 1. Basic Characteristics of Patients With Fingertip Injuries Undergoing Skin Grafting

	Region of Harvested Skin Graft
	Wrist, N = 36	Groin, N = 36
Sex, male to female ratio	35/1	36/0
Age, mean ± SD, y	38 ± 6.8	34 ± 6.2
Surgery time, mean ± SD, min	21 ± 7.2	27 ± 6.3
Body mass index, mean ± SD, kg/m²	26 ± 2.5	27 ± 2.0

3.3. Operation Techniques

Because it was a multicenter study, we strictly stuck to the technique of harvesting grafts. Briefly, we harvested the adjusted skin graft from the wrist or groin in elliptical shape so that it correspond to the size of the lost region in fingertips and tried to remove the subcutaneous fat completely to increase the chance of successful grafting. No meshing procedure was used. Grafts were fixed with absorbable 4.0 (Vicryl, Ethicon Inc, Somerville, New Jersey, USA) running sutures. Then dressing was applied on by four-layered sterile gauze in a moderately tight fashion and due to the low risk of hematoma formation, the grafts were seen after five to seven days.

3.4. Outcomes and Data Analysis

At least six months after the operation, the patients were evaluated clinically and photographically through TPD, light touch, existence of hair on graft, contracture and ulceration of the grafted skin, and color difference with recipient site.

For evaluation of TPD, we used paper clips (Dellon-McKinnon Disk-Criminator, Fabrication Enterprises Inc, White Plains, New York, USA) fixed in definite distances (2, 3, 4, 5, 6, 7, 8, and 9 mm) (Figure 1) (8).

Figure 1. Dellon-McKinnon Disk-Criminator (Two-Point Discrimination Measurement Device)

Patients were asked to close their eyes and we checked the patients’ contralateral healthy fingertip with 2-mm device to determine whether the patient recognized needles as two points. Then we applied it on the grafted skin and asked the patient about points discriminating. If patients did not recognize two points, we repeated test with clips of larger distance.

To evaluate the light touch sense, we used Semmes-Weinstein monofilament aesthesiometers (Semmes Weinstein Corp, Riverdale, New York, USA) with different thicknesses. These are calibrated, single-fiber, nylon threads identified by values ranging from 1.65 to 6.65 mm, which generate reproducible bulky stress. The higher the value of the monofilament is, the stiffer and more difficult to bend it is. We used the filament with constant pressure to bend the filament on the skin of the healthy finger (Figure 2) (9).

Figure 2. Light Touch Semmes-Weinstein Monofilament

If the patients recognized it, we would try the filament on the grafted skin; if they recognized it again, light touch threshold of the grafted finger would be recorded. If they did not recognize it, we would try another larger diameter filament until the patients could recognize it.

Ulcer on the skin graft has been evaluated by one surgeon, blinded to the cases, with direct observation of the fields for any fissures or epidermal separations that had led to exposed subcutaneous fat.

Contracture of the grafted skin was calculated by dividing the decrease in grafted skin size after 18 months by primary skin defect size (primary skin graft size). For measuring the grafted skin’s size, we multiplied the maximum length by the maximum width of the grafted skin. For primary skin graft size, we calculated the defect size by the same method. After 18 months of follow-up, the percentage of the contracture was evaluated by the ratio of the grafted skin area decrease to primary skin graft area.

Hair on the grafted skin was evaluated by counting the hair follicles on the grafted skin.

Color difference between the grafted skin and recipient site was evaluated by analyzing the fingertip photographs on Photoshop CS5 (Adobe Sys Inc, San Jose, California, USA). The photographs were taken by a digital Canon camera (model IXUS800IS, Japan) in the same light and temperature condition. In this method, we evaluated Red (R), Green (G), and Blue (B) color histogram in ten spots of the grafted skin and recipient sites. Then the difference between mean scores of red, green, and blue were calculated as R, G, B; mean score of summation of G, B, and R was the final score for color difference (C). The more C was, the more color difference and less cosmetic result would be (Figures 3 and 4).

Figure 3. Skin Graft Harvested From Groin and the Result on Fingertip

Figure 4. Skin Graft Harvested From Wrist and the Result on Fingertip

3.5. Statistical analysis

Data were collected in a questionnaire designed for this study and SPSS 15 was used to analyze the outcomes. Data were compared using independent samples t test or Mann-Whitney U test according to normal distribution of data on Kolmogorov-Smirnov test. P value <; 0.05 was considered statistically significant.

Figure 5. The Comparison of Two-Point Discrimination Between Study Groups

Skin graft was harvested from wrist in Group 1 and from groin in Group 2. P <; 0.05 (Mann-Whitney U test as the variable was not normally distributed).

Figure 6. The Comparison of light Touch Between Study Groups

Skin graft was harvested from wrist in Group 1 and from groin in Group 2. P <; 0.05 (Mann-Whitney U test as the variable was not normally distributed).

Figure 7. The Comparison of Graft Contracture Percentage Between Study Groups

Skin graft was harvested from wrist in Group 1 and from groin in Group 2. P <; 0.05 (Mann-Whitney U test as the variable was not normally distributed).

Figure 8. The Comparison of Hair Follicle Numbers Between Study Groups

Skin graft was harvested from wrist in Group 1 and from groin in Group 2. P <; 0.05 (Mann-Whitney U test as the variable was not normally distributed).

Figure 9. The Comparison of Graft Color Difference with Recipient Site Between Study Groups

Skin graft was harvested from wrist in Group 1 and from groin in Group 2. P <; 0.05 (independent-samples t test as the variable was normally distributed).

4. Results

The results of clinical evaluation of the fingertip skin grafts from the wrist and groin were compared in Figures 5 through 9. Except color difference variable, none of the other variables showed normal distribution; hence, we used Mann-Whitney U test to compare the results. Skin grafts in none of the fingers showed ulcer and none of the patients reported ulceration during the preceding 18 months. The grafted skin harvested from the volar wrist crease was called group 1 and that harvested from the groin was called group 2.

There was a significant difference between the two groups regarding the five mentioned characteristics including TPD, light touch, hair follicle counts, graft contracture, and color difference (C) (P = 0.000). The TPD mean score was 7.72 ± 0.944 mm (range, 5-10 mm) in group 1 and 8.64 ± 0.867 mm (range, 7-10 mm) in group 2 (Figure 5). The mean score of light touch was 4.39 ± 0.409 mm (range, 3.84-5.07 mm) in group 1 and 4.96 ± 0.505 mm (range, 4.17-5.88 mm) in group 2 (Figure 6). The mean score of the graft contracture percentage from the initial size was 17.36% ± 3.091% (range, 10%-24%) in group 1 and 23.81% ± 2.539% (range, 19%-30%) in group 2 (Figure 7). The mean number of the hair follicles was 0.11 ± 0.398 (range, 0-2) in group 1 and 6.06 ± 3.303 (range, 0-11) in group 2 (Figure 8). The mean score of graft color differences was 17.655 ± 7.49 (range, 3.4-36.2) in group 1 and 143.547 ± 37.844 (range, 101.5-248.1) in group 2 (Figure 9).

4. Discussion

The past few decades have witnessed significant advances in the treatment of fingertip injuries, but to the best of our knowledge, there has not been any comparative study on the clinical differences among donor sites of skin grafting. The current study compared the clinical result of two common donor sites of full-thickness skin grafts on the injured fingertips. Skin grafting is done in two popular ways: split thickness and full thickness. Split-thickness skin graft has epidermal and superficial dermal layer with 0.021 to 0.027 inch (0.053 to 0.068 cm) thickness. Full-thickness skin graft has whole dermal and epidermal layer until 0.07 inch (0.178 cm) (1). Although hyperpigmentation and hair growth were found in most of the full-thickness skin grafts, full-thickness skin grafts have better sensory recovery (due to placement of sensory receptors at the deep dermis) and less contracture as well as breakdown in the fingertip skin; hence, it is the first choice when we have sufficient vascular bed at the receiver site (3, 10-17). On the other hand, full-thickness grafts do not survive as readily as split thickness grafts and require a much better bed to be placed on. When a full-thickness skin graft is used, the recipient area must be free of infection and homeostasis must work properly. Preferred donor areas for full-thickness skin grafts are the groin, volar aspect of the wrist crease, hypothenar region, cubital fossa, medial aspect of the arm, where the skin is thin and the created defect can be closed by undermining and suturing skin edges (18-23). The graft harvested from the wrist volar aspect is easier to harvest due to proximity to the recipient site. The only mentioned disadvantage for volar wrist crease skin graft is its scar which may be interpreted as suicidal attempt (1);nonetheless, the scar is minimal and approximately invisible in most cases.

In two studies, there was a correlation between full-thickness skin graft contracture and graft donor site (12, 24), which were the same as we experienced in our study, with the wrist region contracted meaningfully less than the groin region did. In other studies, the color difference between the grafted skin and recipient site and its correlation with sex, time of surgery, and donor site were analyzed. The results showed a stronger correlation with donor site and the time passed from the surgery (19, 20). Moreover, these results indicated that the volar wrist crease had the most compatible color resemblance with the fingertip skin compared to the groin region (P <; 0.05), which were in accordance with the results of present study. However, we did not assess the effect of time on color change in long term, which could influence this comparison.

In our study, there was a significant difference in the five mentioned variables between the grafted skin harvested from the wrist and the groin (P <; 0.05).

One of the limitations to this study was short follow-up period, because longer follow-up could change the results, especially the color changes. We highly recommend larger sample-sized study to increase reproducibility, longer follow-up period, and comparing more donor regions to each other.

According to our findings, for fingertip injures that were larger than half of the distal phalanx pulp, full-thickness skin graft taken from the volar wrist crease had better clinical result including better TPD and light touch, less hair follicles on graft, less graft color difference with recipient site, and less graft contracture. Overall, the wrist skin graft possesses a number of advantages compared to groin skin graft. Therefore, the wrist-harvested skin graft is a high quality graft that can be considered as a good option to fulfill fingertip injury concern by a hand surgeon.

Acknowledgements

Footnote

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Subject: Knee surgery
Received: 2019/09/9 | Accepted: 2015/02/15 | Published: 2015/02/15

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