Article, Plastic Surgery, Surgery

Risk factors for necrosis of skin flap-like wounds after ED debridement and suture

a b s t r a c t

Background: Skin flap-like wounds are common. These wound flaps are prone to avascular necrosis with simple debrided and sutured, and postoperative hyperplastic scarring and contracture of wound surfaces can adversely affect the patient’s appearance. Here, we evaluate the data of cases with flap-like wounds to identify the causes of flap necrosis.

Methods: Six hundred patients with skin flap-like wounds between January 1, 2013 and December 31, 2016 were retrospectively reviewed. Their age, sex, injury reason, size of flap, length-width ratio of wound, thickness of ped- icle, operation time, injury site, direction of blood perfusion in the flap and operating methods were recorded. The risks for flap necrosis were analyzed with one-factor analysis.

Results: A total success rate of 92.5% (555/600) for flap-like wound reconstruction was obtained. Among 67 flaps with vascular crisis, 22 were salvaged by subcutaneous injection of anisodamine, selective suture removal, and pressure dressing with elastic bandages. For the 45 patients with flap necrosis, there was no significant difference from patients without necrosis in terms of sex, age, and size of flap (P N 0.05). The incidence of flap necrosis was significantly different in terms of injury reason, length-width ratio of wound, thickness of pedicle, operation time, injury site, direction of blood perfusion in the flap and operating methods (P b 0.05).

Conclusion: Injury reason, length-width ratio of wound, thickness of pedicle, operation time, injury site, direction of blood perfusion in the flap and operating methods, rather than age, sex and size of flap, were significant risk factors for necrosis of flap-like wounds.

(C) 2018

Introduction

The management of skin flap-like wounds is one of the most com- mon problems faced by emergency department clinicians. As its name implies, a flap-like wound is characterized by discontinuity and damage to the structure of the soft tissue and is caused by oblique external forces. One side of the tissue is connected to the base of the wound by a pedicle, while the remaining tissue is detached. Its appearance is sim- ilar to a local skin flap intentionally created during plastic surgery, which is also connected to the body by a pedicle.

To minimize traumatic bleeding, pain, emotional reactions, and other patient factors, emergency department clinicians tend to manage such wounds with basic techniques that are easy to perform. Flap-like wounds, often characterized by their irregular shape, differ from tradi- tional skin flaps in plastic surgery. These wound flaps are prone to

* Corresponding author at: Department of Emergency and Department of Burns and Plastic Surgery, The Second Hospital of Shandong University, Jinan 250033, Shandong Province, China.

E-mail address: [email protected] (D. Jiang).

1 These authors contributed equally to this study and share first authorship.

avascular necrosis, which usually results in unfavorable hyperplastic scarring and/or tissue strain (contracture) of the wound surfaces after healing, negatively impacting the physiological and psychological func- tions of many patients [1]. Moreover, additional plastic and reconstruc- tive operations are frequently required after the initial repair [2].

Few relevant research papers have defined and classified these wounds with their associated repair methods. We herein expound the definition and characteristics of common flap-like wounds and analyze the causes of flap necrosis.

Material and methods

Patients and data collection

Between January 1, 2013 and December 31, 2016, a total of 600 pa- tients underwent repair of skin flap-like wounds in emergency depart- ment room, The Second Hospital of Shandong University. Data were collected from the medical files of the patients. Participants with diabe- tes, peripheral vascular disease, radiation, and smoking were excluded from the primary analysis.

https://doi.org/10.1016/j.ajem.2018.07.049

0735-6757/(C) 2018

The preoperative characteristics were sex, age, injury reason, size of flap, operation time, and injury site. Intraoperative characteristics in- cluded the length-width ratio of the wound, thickness of the pedicle, di- rection of blood perfusion in the flap, and operating methods. Postoperative characteristics included injection of anisodamine, selec- tive suture removal, pressure dressing with elastic bandages, external fixation of limbs, and verbal commands of immobilization.

The patients were all operated on by a single medical team. Dur- ing wound debridement, foreign bodies and necrotic tissues were re- moved from the wound under local anesthesia. Both edges of each wound were pushed toward the middle to assess the relaxation of the surrounding tissues. The sizes of flaps ranged from 1 x 0.5 cm2 to 12 x 5 cm2. A wound was termed a small flap-like wound if both

wound edges could make contact at the middle of the wound when pushed together. Otherwise, we termed it a large flap-like wound. Once bleeding had completely stopped, a simple suture was per- formed in situ.

Additional surgical procedures

In some cases, special plastic surgery techniques were adopted when the nonviable edges were trimmed back to the viable tissue:

      • For a small flap, the flap was directly excised and the wound was ex- panded to create an elliptical gap. Then the wound was sutured after subcutaneous dissection (Fig. 1A).

Fig. 1. Schematic diagram. (A) Elliptical debridement of a small U-shaped flap-like wound. (B) The beveled wound edge vertically excised before suturing. (C) An A-T flap created to repair the approximate triangular wound. (D) The V-Y closure technique used to repair flaps with nonviable edges.

  • If the pedicle was wide and the anteroposterior diameter of the flap was small, the beveled wound edge was excised vertically, and the flap portion was removed with the wound base flattened. The sur- rounding skin was then undermined so that a simple suture could close the wound (Fig. 1B).
  • If severe contusion resulted in tenuous circulation within the flap, the injured flap was excised and the wound edge was trimmed, resulting in an approximately triangular wound. An A-T flap then was used to effectively repair the remaining triangular wound. (Fig. 1C).
  • When the edges of the flaps were damaged, the nonviable edges were excised to create a smaller flap by converting a V configuration to a Y configuration; this prevented the remaining flap from being too small to fill the resultant defect [3]. The flap and the wound edges were then brought together in a Y configuration (Fig. 1D).

Table 1

Preoperative patient characteristics.

Influencing factors

Total

Flap necrosis (%)

P-value

Age (year)

b40

324

21 (6.5)

0.475

40-50

166

12 (7.2)

50-60

69

7 (10.1)

>=60

41

5 (12.2)

Sex

Male

426

33 (7.8)

0.720

Female

174

12 (6.9)

Operation time

Within 12 h after wound

522

25 (4.8)

b0.001

Beyond 12 h after wound

78

20 (25.6)

Injury reason

Contusion

397

37 (9.3)

0.018

Incision

203

8 (3.9)

Size of flap Smalla

224

18 (8.0)

0.701

Large

376

27 (7.2)

Injury site

External fixation with a plaster splint was suggested to be applied after operation when dealing with limb trauma to reduce the secondary injury caused by the movement of limbs. Patients were verbally instructed to immobilize their limbs if external fixation was refused. When flap vascular crisis occurred, selective suture removal and subcu- taneous injection of anisodamine were performed to improve the mi- crocirculation [4], and pressure dressing with elastic bandages was adopted to prevent subcutaneous haemorrhage.

All study procedures were approved by the Ethics Review Commit-

Upper

External fixation 77 3 (3.9) 0.002

tee of The Second Hospital of Shandong University, and are in accor-

extremity

Verbal commands of immobilization

189 19 (10.1)

dance with the Helsinki Declaration.

Lower

External fixation 59 4 (6.8)

Statistical analysis

extremity

Trunk

Verbal commands of immobilization

110 16 (14.5)

62 2 (3.2)

Statistical analyses were performed using SPSS Statistics version

19.0. Age, sex, injury reason, size of flap, length-width ratio of the wound, thickness of the pedicle, operation time, injury site, direction of blood perfusion in the flap and operating methods were analyzed with one-factor analysis. P b 0.05 was considered statistically significant.

Results

A total of 600 patients (426 males and 174 females) with skin flap- like wounds received debridement and suture management. Clinical data and analysis results are shown in Tables 1 and 2. Among 67 flaps with vascular crisis, 22 flaps were salvaged by subcutaneous injection of anisodamine, selective suture removal, and pressure dressing with elastic bandages. The postoperative necrosis rate was 7.5% (45/600). Among the 45 patients with flap necrosis, there was no statistically sig- nificant difference in sex from those without flap necrosis (P N 0.05). Pa- tients older than 60 had the highest flap necrosis rate (12.2%), but this was not significantly different from the rate in other age groups (P N 0.05). In addition, the size of flap was not a risk factor for flap necrosis. The percentage of flap necrosis was higher in the contusion group than in the incision group (P b 0.05), and the flap necrosis rate was lower in the patients whose wounds were managed within 12 h after injury than in those treated after 12 h (P b 0.05). Moreover, flap necrosis was prone to appear in low limb injuries, especially among those pa- tients who refused external fixation. According to the direction of blood perfusion in the flap, retrograde flap-like wounds were more prone to necrosis than anterograde flap-like wounds (P b 0.05). The in- cidence of tissue necrosis was higher in narrow flap-like wounds (length-width ratio N 2:1), as was the case for thin flap-like wounds (flaps with little subcutaneous adipose tissue). Repair with plastic sur- gery techniques showed great advantages over simple suturing in situ without special management.

Discussion

A flap-like wound is characterized by discontinuity and damage to the structure of the superficial soft tissue and is caused by oblique

Head and face 103 1 (0.9)

a A wound was termed a small flap-like wound if both wound edges could make contact at the middle of the wound when pushed together. Otherwise, we termed it a large flap- like wound.

external forces. Part of the tissue is connected to the base of the wound by a pedicle while the rest of the tissue is detached, similar to a local skin flap designed during general plastic surgery. Owing to the random direction of the external forces and their unpredictable loca- tions, flap-like wounds, in a sense, are random skin flaps. Postoperative flap necrosis is a challenging complication. As is widely known, a flap’s length-to-width ratio usually cannot exceed 1.5-2 [5], and if the rule is not obeyed appropriately, a certain proportion of the flap is prone to ischemia. This explains why random skin flap transplantation is associ- ated with a 10-20% rate of necrosis [6, 7]. Flap survival is influenced by various recipient etiological characteristics, including peripheral vascu- lar disease, radiation, diabetes mellitus, tumor extirpation, smoking, and infection burden [8, 9].

Table 2

Intraoperative characteristics of flap-like wounds.

Influencing factors

Total

Flap necrosis (%)

P-value

Thickness of pedicle

Flaps with little subcutaneous adipose tissue

143

19 (13.2)

0.003

Flaps with adequate subcutaneous adipose tissue

457

26 (5.7)

Length-width ratio of wound

N2:1

245

26 (10.6)

0.016

<=2:1

355

19 (5.4)

Direction of blood perfusion in the flap Anterograde

210

9 (4.3)

0.028

Retrograde

390

36 (9.2)

Operating methods

Simple suture in situ without special management

144

23 (16.0)

b0.001

Repair with plastic surgery techniques

456

22 (4.8)

Declaration of interest“>The skin wounds of East Asians are more prone to scar formation than those of white Westerners. Therefore, close attention should be paid to wound repair in exposed parts of the body, such as the max- illofacial region, and complex geometric flaps should be avoided. At the same time, the principles of minimally invasive plastic surgery must be followed to reduce damage to the surrounding healthy tis- sue, and any assisting incisions should be designed as simply as pos- sible. If an assisting incision is needed, the surgeon should follow Langer’s lines, even in the emergency setting, to avoid remarkable scar formation after wound healing [10]. Notably, U-shaped flap- like wounds caused by oblique shearing injuries sometimes result in a “trapdoor deformity” after wound healing [11], even if no pro- portion of the flap is ischemic. Furthermore, when repairing large flap-like wounds, if the gap that remains after resection cannot be repaired with simple sutures, the treatment priority should be to de- sign a local skin flap that reconstructs the skin defect, so that the flap is similar to adjacent tissues in color, thickness, and flexibility after the operation [12].

Our study did not include certain skin flap-like wound. For instance, if a thin flap is equipped with poor vascular perfusion and little contu- sion, the subcutaneous tissues under the flap should be removed, and the skin on the wound should be replanted in situ with pressure ban- daging. An in situ flap taken from avulsed skin can be utilized to cover wounds with cutaneous deficiencies.

Trauma threatens human life [13]. The main principle of emer- gency medicine is to first save the patient’s life. Thus, in life- threatening situations, many emergency department clinicians ne- glect elaborate Wound management [14]. However, if the patient’s condition is stable, management of skin wounds according to the principles of plastic and cosmetic surgery can promote wound healing and inhibit scar proliferation, improving aesthetic outcomes and avoiding the need for further surgical reconstruction [15, 16]. We believe that this should be a general trend in emergency trauma surgery. Here we analyzed the data of flap-like wounds to determine the causes of flap necrosis, hoping to provide a reference for clinical colleagues.

Acknowledgments

The authors thank Chen Li at Fuwai Hospital Chinese Academy of Medical Sciences for the preparation of the schematic diagram.

Funding

This work was supported by grants from the National Natural Sci- ence Foundation Project [grant numbers 30772258, 81071560, and 81372074] and the Science and Technology Development Projects of Shandong province [grant number 2015GSF118041].

Declaration of interest

The authors declare no conflicts of interest.

References

  1. Nabili V, Knott PD. Advanced lip reconstruction: functional and aesthetic consider- ations [J]. Facial Plast Surg 2008;24(1):92-104.
  2. Diaz-Siso JR, Parker M, Bueno EM, et al. Facial allotransplantation: a 3-year follow-up report [J]. J Plast Reconstr Aesthet Surg 2013 Nov;66(11):1458-63.
  3. Trott Alexander T. Wounds and lacerations: emergency care and closure [M]. Phila- delphia: Elsevier Mosby; 2005; 143-4.
  4. Wei X, Zhang Z, Han L, et al. Protective effect of anisodamine on reperfusion injury of skeletal muscles in rabbit [J]. Acta Orthop Scand 1998;69(6):633-7.
  5. Cao B, Wang L, Lin D, Cai L, Gao W. Effects of lidocaine on random skin flap survival in rats [J]. Dermatol Surg 2015;41:53-8.
  6. Yao QJ, Xu MD, Chen B. Effects of different intermittent positive pressure on random pattern flap survival [J]. [Article in Chinese] Journal of the Fourth Military Medical University 1999;20(5):453-4. https://doi.org/10.3321/j.issn:1000-2790.1999.05.

    028.

    Xu Peng-Fu, Miao-Jie Fang, Yu-Zhi Jin, et al. Effect of oxytocin on the survival of ran- dom skin flaps [J]. Oncotarget 2017;8(54):92955-65.

  7. Selber JC, Kurichi JE, Vega SJ, et al. Risk factors and complications in free TRAM flap

    breast reconstruction [J]. Ann Plast Surg 2015;56:492-7.

    Zhang P, Feng J, Liao Y, Cai J, Zhou T, Sun M, et al. Ischemic flap survival improve- ment by composition-selective fat grafting with novel adipose tissue derived product-stromal vascular fraction gel [J]. Biochem Biophys Res Commun 2017. https://doi.org/10.1016/j.bbrc.2017.11.196.

  8. Truong PT, Lee JC, Soer B, et al. Reliability and validity testing of the Patient and Ob- server Scar Assessment Scale in evaluating linear scars after breast cancer surgery [J]. Plast Reconstr Surg 2007 Feb;119(2):487-94.
  9. Webster RC, Benjamin BJ, Smith RC. Treatment of “trap door deformity” [J]. Laryngo-

    scope 1978 Apr;88(4):707-12.

    Dzubow LM, Zack L. The principles of cosmetic junctions as applied to reconstruction of defects following Mohs surgery [J]. J Dermatol Surg Oncol 1990;16(7):353-5.

  10. Sabatino F, Moskovitz JB. Facial wound management [J]. Emerg Med Clin North Am 2013;31(2):529-38.
  11. Niamtu JR. Complications in cosmetic facial surgery [J]. Oral Maxillofac Surg Clin North Am 2009;21(1):98-9.
  12. Niamtu JR. The accredited cosmetic facial surgery office: a paradigm shift in oral and maxillofacial surgery [J]. J Oral Maxillofac Surg 2009;67(10):2072-9.
  13. Morris C, Kushner GM, Tiwana PS. Facial skeletal trauma in the growing patient [J]. Oral Maxillofac Surg Clin North Am 2012 Aug;24(3):351-64.