Pelnac^® artificial dermis assisted by vacuum sealing drainage for treatment of severe avulsion injuries of the fingers

Abstract

Purpose

This study aimed to evaluate the outcomes of Pelnac assisted by vacuum sealing drainage in managing severe avulsion injuries of the fingers.

Methods

This prospective study was conducted from May 2017 to September 2023, involving 12 consecutive patients with severe avulsion injuries of the fingers. Patients underwent single-stage or two-stage procedures employing Pelnac assisted by vacuum sealing drainage (VSD) for the management of severe avulsion injuries of the fingers. Post-operative follow-up was routinely scheduled, and aesthetic and functional outcomes, sensory recovery, complications were recorded.

Results

Twelve patients were included in the analysis, consisting of 9 males and 3 females, with a mean age of 30.6 ± 11.0 years. All patients presented with severe damage to tendons and deep tissues, as well as varying degrees of bone exposure and injury, with average defect area of 36.9 cm² (range, 11 to 180 cm²). At the final follow-up (mean, 14 months; range, 12 to 29 months), the average score on the Fingertip Injuries Outcome Score (FIOS) was 14.3 (SD 3.9, range 10 to 22), with 6 patients achieving excellent result, 4 classified as good and 2 as fair. Patients reported an average satisfaction score of 74.0 (SD 11.6; range 51 to 94) regarding the aesthetic appearance. The average score on the Vancouver Scar Scale score was 2.3 (SD 2.1, range 1.0 to 7.4). Ten patients reported normal or near-normal sensation, while 2 patients experienced slight sensory loss. The average score on the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire was 13.2 (SD 8.5, range 0 to 47). No infections or hematomas were reported during hospitalization or after discharge.

Conclusion

Pelnac, assisted by VSD, proved to be an effective approach for managing severe avulsion injuries of the fingers. This approach can be considered as a viable alternative for addressing severe injuries or complex wound conditions.

Introduction

Severe avulsion injuries of the fingers frequently occur in the productive age groups, significantly contributing to emergency department admissions [1]. Inadequate or imprecise management of these injuries can lead to substantial functional impairments, loss of productivity, and reduced quality of life [2, 3]. Due to the substantial tissue exposed, severe intimal contusion, and artery and nerve avulsion in a substantial proportion of cases, it poses a significant challenge to surgeons.

Traditional treatment methods employed over the past decades have often failed to meet clinical demands. For instances, conventional skin grafting or flap procedures (local, free, cross-abdominal), often combined with gauze pressure dressings, are frequently associated with cumbersomeness, limited donor site availability, donor site morbidity, graft necrosis and unfavorable cosmetic outcomes [4, 5]. While microsurgical techniques can effectively facilitate vascularized flap reconstruction, they require specialized skills and present challenges in primary care settings. In recent decades, the development of skin substitutes has aimed to reduce donor site morbidity while enhancing functional and aesthetic outcomes. Products such as Integra (Integra LifeSciences, Inc., Plainsboro, NY, USA) [6], AlloDerm ((LifeCell Corporation, Branchburg, NJ, USA) [7], Dermagraft (Smith and Nephew, Largo, FL, USA) [8], Terudermis (Olympus Terumo Biomaterials Corp., Tokyo, Japan) [9], and Pelnac (Gunze Limited, Kyoto, Japan) [10] have emerged as effective tools for reconstructing complex full-thickness wounds and gained popularity in clinical practice. Notably, Pelnac, a bilayer dermal substitute, has shown promise in addressing traumatic injuries involving exposed bone and tendon [10,11,12], featuring an atelocollagen matrix that supports dermal regeneration and a semipermeable silicone layer that acts as a temporary epidermis. Despite its successful application in various contexts, the efficacy of Pelnac in managing severe finger avulsion injuries remains underexplored.

In this study, we aimed to present our successful experience of utilizing Pelnac dermal substitute in treatment of 12 cases of severe finger avulsion injuries with skin and soft tissue defects and exposed bone and/or tendon.

Methods

Study design

This prospective study was conducted from May 2017 to September 2023. The inclusion criteria included consecutive patients presenting with severe finger avulsion injuries, characterized by skin and soft tissue defects, as well as exposed bone and/or tendon, who underwent surgical treatment involving the Pelnac dermal substitute at our institution. In these cases, the loss of surrounding tissue rendered definitive treatment options, such as simple wound care, primary closure, and skin grafting, incapable or inadequate; or more complex reconstructive techniques were deemed unacceptable by the patients. Exclusion criteria included advanced age (≥ 70 years), diabetes, heavy smoking, and prolonged use of glucocorticoids (all of which could impair wound healing), and patient lacking complete assessments for at least 12 months.

The study protocol was approved by the ethics community of the local hospital, and written informed consent was obtained from each patient.

Operative procedure and management

All operations were performed by the first author (Z.L.). Under brachial plexus block anesthesia, the wound was irrigated alternately with hydrogen peroxide, povidone-iodine, and saline. Initial debridement was performed to remove necrotic tissue, debris, and foreign materials while preserving as much viable skin and deep tissue as possible, including damaged skin, tendons, and surrounding structures.

If the wound was relatively fresh, the damaged tendons were repaired with interrupted sutures, addressing both the injured tendons and the exposed bone. A single-layer artificial dermis Pelnac (collagen layer without a silicone membrane) was then applied to the deep wound bed (exposed bone, damaged, and deficient tendons). The avulsed skin was repositioned over the dermal layer and secured with interrupted sutures. For residual defects that could not be sutured closed, the area was covered with a bilayer artificial dermis (reinforced with a silicone membrane), and continuous vacuum sealing drainage (VSD) therapy was applied (Wuhan VSD Medical Science & Technology Co. Ltd, Wuhan, Hubei, China) therapy.

In cases of heavy contamination, primary debridement and VSD suction were performed. Once the wound appeared cleaner and showed no significant signs of infection, the same method for artificial dermis repair was utilized at a later stage, maintaining VSD suction at pressures of 0.02 to 0.04 MPa. Postoperatively, antibiotics were administered for three days to prevent infection. One week after the application of artificial dermis, the VSD was removed, and the viability of the graft was assessed. Dressings were changed regularly, and three weeks later, the silicone membrane of the artificial dermis was removed. Residual wounds that did not undergo skin grafting were allowed to epithelialize naturally.

Active movement of the wrist joint is permitted one week post-operatively, followed by movement of the metacarpophalangeal joints after three weeks. Movement of the interphalangeal joints can begin at four to six weeks. In cases of phalanx fractures, active movement of the interphalangeal joints may commence approximately two months later, depending on the healing status of the fracture and following the removal of Kirschner wires.

Follow-up

After discharge, each patient underwent routine follow-up visits at 2 weeks, and at 1, 3, 6, and 12 months on an outpatient basis or via Wechat. At each visit, we assessed and documented the survival status of the grafted skin, scar quality, and any complications such as infection, hematoma, or seroma. At the final visit, we employed the Fingertip Injuries Outcome Score (FIOS), a validated and reliable assessment tool, to evaluate the outcome of fingertip injuries [13]. This scoring system was developed based on nail, finger length, pulp, bone, cosmesis, sensation, pain, range of motion, grip strength, and the ability to return to work, yielding a total score ranging from 10 to 32, with higher indicating poorer outcome. The results were categorized as excellent (≤ 12), good (13–18), fair (19–24), and poor (≥ 25). Patient satisfaction with the aesthetic outcome (using normal healthy skin as a benchmark, scored at 100 points), functional recovery of the affected limb, and the sensory perception of the grafted area were additionally evaluated. The Vancouver Scar Scale was employed to assess scar quality based on pigmentation, vascularity, pliability, and height, with higher scores indicating more severe scarring [14] (Table 1). The Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire was utilized to measure patients’ abilities of the injured limb to perform daily activities [15]. This self-reported questionnaire consists of 30 items, with scores ranging from 0 (indicating no disability) to 100 (indicating maximum disability). Sensory recovery was reported by patients, categorized as ‘normal or near normal,’ ‘slight loss,’ ‘significant loss,’ or ‘complete loss,’ using the contralateral uninjured side as a control for comparison.

Table 1 Vancouver Scar Scale

Results

Twelve patients were included, consisting of 9 males and 3 females, with a mean age of 30.6 ± 11.0 years (range, 20 to 56 years). The mechanisms of injury were as follows: 6 cases involved machine entrapment, 3 involved wheel crushing, 1 involved compression injury, 1 involved belt entrapment, and 1 case involved a heavy object striking the fingers. Regarding specific finger involvement, 2 cases involved index, middle, ring, and little fingers, 2 cases involved the ring and middle fingers, 3 cases involved the middle and index fingers, and 5 cases involved the thumb. All patients presented with severe damage to tendons and deep tissues, as well as varying degrees of bone exposure and injury. The locations of these injuries included 3 cases on the dorsal side of the fingers and 5 cases on the palmar side, with 3 cases involving injuries to the metacarpophalangeal joints or interphalangeal joints, and 1 case with additional hand injuries (palm and wrist). The average defect area was 36.9 cm², ranging from 11 to 180 cm². (Table 2)

Table 2 Baseline clinical and surgical characteristics of the included patients

fexposed (mean, 14 months; range, 12 to 29 months), the average score on the FIOS was 14.3 (SD 3.9, range 10 to 22), with 6 patients achieving excellent result, 4 classified as good and 2 as fair. The patients reported an average satisfaction score of 74.0 (SD 11.6; range 51 to 94) regarding the aesthetic appearance. The VSS assessment yielded an average score of 2.3 (SD 2.1; range 1.0 to 7.4), indicating favorable outcomes. Regarding sensory recovery, 10 reported normal or near-normal sensation, while 2 patients experienced slight sensory loss. The average score on the DASH questionnaire was 13.2 (SD 8.5, range 0–47), indicating that the majority of patients (11 out of 12) regained the ability to perform daily activities without pain or restrictions related to tissue adhesion.

No complications (e.g., infection, hematoma) were reported or observed during the follow-up period.

Type cases

Figure 1 described a 34-year-old man admitted 2 h after sustaining a machine entrapment injury to his right hand, resulting in extensive skin and soft tissue defects involving the index, middle, ring and little fingers. Preoperative evaluations revealed significant damage to the dorsal skin and proximal interphalangeal joint of the middle finger, bone fracture, and extensor tendons exposure, with a wound measuring 7.0 cm × 8.0 cm (A-C). Following thorough debridement, fracture reduction and internal fixation were performed along with Kirschner wire stabilization of the interphalangeal joints (D to F). A single-stage repair using Pelnac dermal substitute addressed the damaged tendons and avulsed skin (G and H), with VSD applied over the wound (I). At 12 months postoperatively, the skin was well-contoured with no significant scarring or pigmentation, exhibiting durable, elastic texture and restored protective sensation, with no pain or sensory abnormalities were reported; but he had a significant flexion limitation in the third to firth fingers, due to the initial comminuted intra-articular fractures (J to L).

Fig. 1

A 34-year-old man sustained a machine entrapment injury to his right hand, resulting in extensive skin and soft tissue defects involving the index, middle, and ring fingers, with a wound measuring 7.0 cm × 8.0 cm (A-C). Following thorough debridement, fracture reduction and internal fixation were performed, with Kirschner wire stabilization of the interphalangeal joints (D to F). A single-stage repair using the Pelnac dermal substitute addressed the damaged tendons and avulsed skin (G and H), with VSD covering the wound (I). The postoperative 12-month assessment showed well-contoured skin with no significant scarring or pigmentation, but he had a significant flexion limitation in the third to firth fingers, due to the initial comminuted intra-articular fractures (J to L)

Figure 2 presented a 40-year-old man admitted 9 h after a machine entrapment injury (wool carding machine) to his right hand, resulting in extensive skin and soft tissue defects involving the index, middle, ring and little fingers. Preoperative evaluation revealed significant contamination with hair and debris, along with severe damage to the dorsal skin, bone, and extensor tendons, and a wound measuring 6.5 cm × 9.0 cm (A). After thorough debridement, first-stage procedure using single-layer Pelnac was applied (B), with negative pressure wound therapy (VSD) used. Once the wound appeared fresh and free of infection, a second-stage repair using Pelnac was performed to address the remaining skin defects and exposed tendons (C and D). VSD continued to cover the wounds, allowing for natural epithelialization without the need for skin grafting. At the 14-month follow-up, the wound surface demonstrated good cosmetic appearance, with no significant scarring or pigmentation, and restored protective sensation, and satisfactory hand function, with no pain or sensory abnormalities was reported (E to H).

Fig. 2

A 40-year-old man suffered a machine entrapment injury to his right hand, resulting in extensive skin and soft tissue defects involving the index, middle, and ring fingers, with severe damage to the dorsal skin, bone, and extensor tendons, and a wound measuring 6.5 cm × 9.0 cm (A). After thorough debridement, single-layer Pelnac was applied as first stage procedure (B). The second-stage repair using Pelnac to address the remaining skin defects and exposed tendons (C and D). The 14-month follow-up assessment showed favorable cosmetic appearance satisfactory hand function (E to H)

Discussion

Severe avulsion injuries of the fingers present a significant clinical challenge, frequently accompanied by bone and tendon damage, complicating the surgical intervention. Given their critical social and functional implications, achieving optimal functional and aesthetic outcome should be prioritized when a reconstructive surgery is considered. Conventional treatments are often inadequate to meet these requirements. In this study, we used the dermal substitute Pelnac in either a single- or two-stage procedure (for severely contaminated cases) to effectively manage severe avulsion injuries of the fingers, resulting in favorable functional and aesthetic outcomes.

The unique bilayer structure of Pelnac is regarded as the principal factor underlying the favorable outcomes observed in this study. First, the underlying atelocollagen matrix layer serves as a scaffold for the ingrowth of fibroblasts, macrophage and endothelial cells, facilitating the formation of a true dermis; the overlying silicone layer acts as a temporary barrier, preventing bacterial invasion and moisture evaporation, thereby reducing the infection. Second, by providing a conducive environment for blood vessel formation, the artificial dermis enhances angiogenesis, improving nutrient and oxygen supply to the healing tissue, which is critical for successful repair [16]. Third, it aids in minimizing scar formation by promoting the proper alignment and integration of new tissue, ultimately improving aesthetic outcome [17]. Fourth, incorporating artificial dermis into the wound bed has been shown to accelerate the healing process, leading to reduced overall recovery time and improved functional outcomes. Our finding, indicating that the overwhelming majority of patients had favorable functional and aesthetic outcomes, substantiates the ability of Pelnac to translate its theoretical advantages into clinical effectiveness. This finding aligns with previous research examining various severe injuries or complex surgical conditions, including degloving injuries of the upper extremity, revision surgery following conventional treatment failures for degloving injuries, reconstruction after skin cancer excision, and the management of burn contractures [11, 18,19,20].

The successful “take” of Pelnac and skin graft relies on the thorough preparation of a clean wound bed; otherwise, any residual devitalized tissue or excretions from host tissues could potentiate failure. In our clinical practice, adequate and thorough surgical debridement is mandatory, and we utilized the different strategies based on the degree of contamination of the wound. For a clean wound after debridement, single-stage procedure is feasible, involving single-layer Pelnac placed over the underlying bone and tendons, with the avulsed skin repositioned, and double-layer Pelnac coving the remaining wound. For severely contaminated wound, a staged approach was employed: initial debridement and VSD therapy, followed by the same procedure as used in clean wound in the second stage. This strategy has also been employed in the treatment of other severe injuries or complex wounds, yielding similarly excellent outcomes [11, 12, 20].

The application of VSD therapy was another factor contributing to the favorable outcomes, and in this study, VSD was generally applied over the grated skin for at least 3 weeks. The potential mechanisms of VSD therapy include: (1) infection prevention, as the sealed negative-pressure environment enhances skin graft viability and reduces bacterial invasion [21]; (2) improved microcirculation, with studies showing that sustained negative pressure up to 125 mm Hg can increase peak blood flow at the wound site by approximately fourfold, thereby promoting healing [22]; and (3) reduced local edema through exudate absorption, alleviating swelling [21]. In our study, we observed no infections, hematomas, or seromas, likely due to the application of VSD. While some studies have reported a significantly reduced “wait time” for artificial dermis incorporation and vascularization [23, 24], we could not confirm this due to the absence of a comparison group.

The strengths of this study include its focus on a case series of severe avulsion injuries of the fingers, a minimum follow-up of 12 months and use of various tools to evaluate outcomes. However, several limitations warrant consideration: the absence of a control group for comparison with the conventional approaches; the lack of histological data regarding the incorporation of Pelnac into the host tissues at different stages; and the small sample size from an orthopaedic-specialty hospital, which might affect the validity and generalizability of the findings.

In conclusion, the combination of artificial dermis Pelnac and VSD therapy has proven to be an effective approach for managing severe avulsion injuries of the fingers. This approach facilitates tissue reconstruction and achieves favorable functional and aesthetic outcomes while minimizing complications; therefore, it can be considered a viable alternative for addressing severe injuries or complex wound conditions.