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ORIGINAL ARTICLE
Year : 2019  |  Volume : 32  |  Issue : 4  |  Page : 1256-1261

Evaluation of dorsal metacarpal artery perforator flaps in the reconstruction of hand soft-tissue defects


1 Department of Plastic Surgery, Kafr Al-Shaikh General Hospital, Kafr Al-Shaikh, Egypt
2 Department of General Surgery, Faculty of Medicine, Menoufia University, Menoufia, Egypt
3 Department of Plastic Surgery, Faculty of Medicine, Menoufia University, Menoufia, Egypt

Date of Submission24-Nov-2018
Date of Decision31-Dec-2018
Date of Acceptance13-Jan-2019
Date of Web Publication31-Dec-2019

Correspondence Address:
Tamer H Al-Baz
Kafr Al-Shaikh
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mmj.mmj_365_18

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  Abstract 


Objective
Evaluation of the dorsal metacarpal artery perforator (DMAP) flaps in the reconstruction of hand soft-tissue defects.
Background
The DMAP flap is a nonconventional solution for treating hand and finger defects. We present our experience in resurfacing a variety of soft-tissue defects of hand and fingers with this single-stage flap, reducing the need for other conventional flaps which may need more than one stage for reconstruction.
Patients and methods
This study was done on 20 patients (18–65 years) with soft-tissue defects of the hand and fingers, following trauma in 15 patients, postburn deformity reconstruction in four patients, and in one patient for post-tumor excision, presented at the Menoufia University Hospital and Kafr Al-Shaikh General Hospital over a 1-year period.
Results
The average flap size was 6 × 2.5 cm; raised from the dorsum of the hand as an island elliptical flap. Twelve flaps were used to resurface defects between metacarpophalangeal and proximal interphalangeal joints; three flaps were used to resurface defects between proximal and distal interphalangeal joints; one flap was used to resurface defect beyond the distal interphalangeal joint; and four flaps were used to resurface web space defects. The donor site closed primarily in all cases. Complications were distal necrosis in two flaps and congestion in two flaps. Wound dehiscence of the donor site occurred in two cases.
Conclusion
DMAP flap is a reliable alternative for treating defects on the hand and fingers. The flap offers the surgeon simple, single-stage, and fast procedure with minimal donor site morbidity and with preservation of functional and esthetic outcomes.

Keywords: arteries, fingers, hand, metacarpal bones, perforator flap


How to cite this article:
Al-Baz TH, Gad SS, Keshk TF, Aly MS. Evaluation of dorsal metacarpal artery perforator flaps in the reconstruction of hand soft-tissue defects. Menoufia Med J 2019;32:1256-61

How to cite this URL:
Al-Baz TH, Gad SS, Keshk TF, Aly MS. Evaluation of dorsal metacarpal artery perforator flaps in the reconstruction of hand soft-tissue defects. Menoufia Med J [serial online] 2019 [cited 2020 Jul 7];32:1256-61. Available from: http://www.mmj.eg.net/text.asp?2019/32/4/1256/274264




  Introduction Top


The dorsal metacarpal artery perforator (DMAP) flaps are island flaps raised on the dorsum of the hand, either as fasciocutaneous flap or adipofascial flap, for coverage of dorsal hand defects and fingers soft-tissue defects proximal to the fingertip. DMAP flap was first described by Quaba and Davison in 1990, as the distally based dorsal hand flap, that is not based on the dorsal metacarpal arteries (DMAs) (as described by Earley and Milner in 1987), but rather on a constant perforator which arose directly from the DMA 0.5–1 cm proximal to the corresponding metacarpophalangeal (MP) joint (just distal to the juncture tendinae) or, when the latter is absent, a perforator from the palmar system was demonstrated in the second, third, and fourth intermetacarpal spaces. This constancy of this cutaneous perforator makes the DMAP flap more reliable compared with the reverse and the extended reverse DMA flaps [Figure 1] [1].
Figure 1: Illustration showing the vascular basis of the flap: (a) normal vascular anatomy and (b) dorsal metacarpal artery perforator flap.

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The flap is designed, usually as an ellipse, on the DMAP closest to the defect. The flap design is limited between the distal edge of the extensor retinaculum, the MP joint, and the outer borders of the adjoining metacarpals [Figure 2] [1].
Figure 2: Illustration showing the limit of the flap.

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The chief advantages of this flap: that it is a local flap, simple to raise, single-stage reconstruction, thin pliable skin replacement (thus eliminating the need for the debulking procedures), offers early mobilization (hence decreased risk of stiffness), reduced hospital stay, cost saved by avoiding second or more surgical procedures, early return to work, and minimal donor site morbidity with nice esthetic results (as the laxity of the dorsal skin permits the primary closure of the donor defect) [2].

Being a single-stage flap is an advantage reducing the use of other conventional flaps, for example, local, as a cross-finger flap or distant, as abdominal and groin flaps, as these flaps require more than one surgical stage to divide and inset the flap, longer immobilization and stiffness of the hand, and hence more hospitalization and major delay in recovering the hand function and late return to work. In case of a cross-finger flap, flap division was at 3 weeks and recovery of movement up to another 3 weeks, requiring minimum 70 days even for simple skin defects. The distant flaps usually required more than two stages to thin and adjust the flaps hence the time scale for recovery of movement and return to work is often uncertain [2].

With DMAP flaps, when no skin graft is used, the hand is routinely mobilized in a week, hence full range of movement within 10 days and return to work in 2–3 weeks is possible. In cases, where a skin graft was used, immobilization of the hand in the slab continued for 10 days to secure the take of the graft, hence restoring the full range of painless movement in ∼2–3 weeks and return to work in about 3 weeks [2].

Moreover, a longitudinal segment of one of the tendons of the extensor digitorum communis may be incorporated into the flap. This 'vascularized graft' may be used to reconstruct missing distal segments such as the central slip of the extensor tendon, making this flap potentially useful to reconstruct cases of boutonniere deformity with associated skin damage as may occur in burns or rheumatoid arthritis [3].

The major drawback of the DMAP flap is that the movement of the flap is done by twisting of the pedicle, which may lead to kinking and occlusion of the vessels, especially the veins, which are a low-pressure system leading to ischemia or venous congestion. Therefore, it is important to ensure that there is no injury (e.g., contusion to the dorsal skin, previous injection of a local anesthetic, deep laceration extending into the web space, or metacarpal neck or head fracture) in the vicinity of the selected perforator, also secure meticulous hemostasis and minimize any compression of the flap or the bridge segment [1].

The donor site morbidity of the flap is minimal, as the lax dorsal skin allows primary closure of the donor defect and in most cases scars on the dorsum of the hand settle down well; however, flaps wider than 3 cm may need a full-thickness skin graft for donor site closure [1].

This flap is a perfect option for coverage of small-sized and medium-sized defects on the hand and fingers. As regards single-stage procedure, the constancy of the perforator and also the quality of the transferred tissues is optimal as the 'like-to-like' principle of reconstruction is respected (color match, skin thickness, and texture) [4].

The aim of the present study was to evaluate the versatility of the DMAP flap in resurfacing a variety of soft-tissue defects of the hand and fingers, reducing the need for other conventional flaps, which may need more than one stage for reconstruction.


  Patients and methods Top


This prospective study was conducted on 20 patients with soft-tissue defect and deformities on the dorsum of the hand, soft-tissue defects of the fingers (proximal to the finger tip), web space and distal palm defects, following trauma in 15 (75%) patients, postburn deformity reconstruction in four (20%) patients and in one (5%) patient for post-tumor excision, presented at Menoufia University Hospital and Kafr Al-Shaikh General Hospital over the period from June 2017 to June 2018, after obtaining an informed consent from all patients. We excluded patients with possibility of traumatic injury to the donor site and perforator, include metacarpal neck fractures, lacerations extending into the web space, and contusion on the dorsum of the hand. Age, gender, history, and smoking were recorded. General examination to assess the general condition of the patients and exclude any associated critical injuries was done. Every participant had been informed about the “aims, methods, sources of funding, any possible conflicts of interest, institutional affiliations, the anticipated benefits and potential risks of the study”. Also an informed consent was obtained from all participants.

Routine laboratory investigation including complete blood count, renal function tests, liver function tests, fasting and postprandial blood sugar, and coagulation profile were done and recorded.

Plain radiography of the hand to exclude metacarpal head or neck fractures which may cause injury to the perforator or any other hand fractures which may require reduction and fixation. A preoperative Doppler assessment of the perforator is not required, as the perforator is always present even if the DMA is absent because the perforator arises directly from one of the branches of the deep palmar arch.

Operative technique

The patients were operated under general, regional, or local anesthesia, with tourniquet on the arm without complete exsanguination to aid visualization of the pedicle. The flap was designed as an ellipse with the axis of the flap marked in the midline between the adjacent metacarpals. The DMA perforator closest to the defect was marked at the level of the metacarpal neck in the intermetacarpal space. The designed flap was limited between the distal edge of the extensor retinaculum, the MP joint, and the outer borders of the adjoining metacarpals. The location of the perforator represents the pivot point of the flap.

The skin and subcutaneous tissue on the lateral border of the flap was incised first until the underlying extensor tendon was seen. The aim of the lateral incision is to identify the correct plane of flap elevation. The flap was elevated in the loose areolar plane superficial to the extensor tendon paratenon. Then proximal and medial borders of the flap were incised using the previously identified plane of elevation and the flap was elevated from proximal to distal.

Dissection of the most distal portion of the flap was done, and subcutaneous tissue and fascia surrounding the perforator were freed up without skeletonization, as the connective tissue surrounding the artery contains the draining veins, until the flap could be rotated into the defect without any kinking or tension on the pedicle. Care is taken to preserve the extensor tendon paratenon as this will maintain the gliding of the extensor tendon postoperatively and prevent any adhesions to the overlying tissue, especially if closure of the donor area with graft is planned.

Flap was anchored to the defect using PROLENE (Polypropylene, Ethicon Inc., a subsidiary of Johnson and Johnson) sutures 4/0 after good hemostasis. The donor site was closed in two layers: subcutaneous layer by VICRYL (Polyglactin 910, produced in Cornelia, Georgia, USA) sutures 3/0 and skin by PROLENE sutures 3/0 [Figure 3], [Figure 4], [Figure 5].
Figure 3: Operative steps: (a) marking and designing the flap over the fourth DMAP for coverage of post-traumatic skin and soft-tissue defect with exposed extensor tendon on the dorsum of the left little finger of a male patient of 34 years old. (b) Incision of the lateral border of the flap first to identify the correct plane for flap elevation. (c) Complete flap elevation based solely on the DMAP. (d) Flap inset and anchoring to the defect with primary closure of the donor area and good vascularity seen. (e) Flap 2 months later with good esthetic and functional outcome. DMAP, dorsal metacarpal artery perforator.

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Figure 4: A male patient of 64 years old with suspicious squamous cell carcinoma over the radial side of the dorsum of the left hand: (a) marking of the lesion to be excised with safety margin, and marking and designing of the flap over the second DMAP, (b) the soft-tissue defect after excision, (c) elevation of the flap, (d) flap inset and anchoring to the defect with primary closure of the donor site, (e) 1-week postoperatively. DMAP, dorsal metacarpal artery perforator.

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Figure 5: A male patient of 18 years old presented with post-traumatic skin loss over the dorsum of the proximal interphalangeal joint of the left index with loss of the central slip of the extensor tendon: (a) flap design as a tear drop over the second DMAP, (b, c) elevation of the flap together with parts of the extensor digitorum tendon for reconstruction of the central slip, (d) flap inset and primary closure of the donor site. DMAP, dorsal metacarpal artery perforator.

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  Results Top


Twenty cases with soft-tissue defect and deformities on the dorsum of the hand, soft-tissue defects of the fingers (proximal to the finger tip), web space, and distal palm defects were managed by the DMAP flap and followed up for 6 months to 1 year. The patients ranged in age from 18 to 65 years with 14 (70%) men and six (30%) women. The flap size ranged from 4 to 10 cm in length and 1–3.5 cm in width. Twelve (60%) flaps were used to resurface defects between MP and proximal interphalangeal (PIP) joint; three (15%) flaps were used to resurface defects between PIP and distal interphalangeal (DIP) joint; one (5%) flap was used to resurface defect beyond the DIP joint; and four (20%) flaps were used to resurface web space deformities [Table 1]. The donor site was closed primarily in all cases with no need for skin grafting [Table 2]. No postoperative wound infection or hemorrhage was recorded. Sixteen (80%) flaps survived completely, two (10%) flaps suffered from distal necrosis and were managed by daily dressing and healed without surgical intervention; and two (10%) flaps suffered from congestion and were managed conservatively by elevation of the affected limb and release of any tension suture over the pedicle and survived completely. Wound dehiscence of the donor site occurred in two (10%) cases where the flap width was 3.5 cm; this was managed by daily dressing and healed with secondary intention with nice esthetic results. Donor site morbidity was minimal with nice esthetic results; only two cases suffered from hypertrophic scars and three cases with hyperpigmentation. Also the functional and esthetic outcomes of the recipient site were good with no complications [Table 3] and [Table 4].
Table 1: Distribution of the studied cases according to site of the defect or deformity (n=20)

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Table 2: Data of the flap

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Table 3: Postoperative complications data

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Table 4: Follow-up data

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  Discussion Top


The distally based skin island flap described by Maruyama in 1990 was designed over the intermetacarpal space and elevated in continuity with the underlying DMA, which is divided at its proximal end. Dissection of the vascular pedicle is continued distally to the web space taking care to preserve the connections between the DMA and its branches and the branches of the palmar digital arteries [5].

In 1990, Quaba has proven that it is not necessary to incorporate the DMA with island flaps from the dorsum of the hand as they are based distally on the cutaneous perforators given off by the second, third, and fourth DMAs, about 1 cm proximal to the metacarpal heads. The skin island is orientated longitudinally so as to incorporate the longitudinal vascular network formed by anastomoses between successive branches of individual DMAs. Venous drainage is ensured by the preservation of the tissues around the arterial pedicle and some subcutaneous veins. Flow in these veins is reversed [3].

Even if the DMA is absent (as shown by many anatomical studies), the perforator is constant and arises directly from one of the branches of the deep palmar arch at the same site.[4]

Constancy of the perforators allows elevation of these flaps even in scarred tissues. This is in contrast to the arterial circulation of the skin of the palm where the number of vessels is more numerous, but the arrangement is haphazard with minimal anastomoses. Isaraj [6] in 2011 reported two cases of using the DMAP flap elevated from a scared dorsum of the hand to release postburn finger contracture.

Also in 2010, Bailey et al. [7] reported utilizing the DMAP flap harvested from a previously skin-grafted area for dorsal fifth digit coverage.

Our prospective study was done on 20 cases who underwent dorsal digital, lateral digital, palmar digital, web space, and dorsum of the hand defects. Fifteen were caused by trauma, 14 patients were men and this is consistent with what was mentioned by Petkoval, who stated that the highest incidence of trauma to the hand and digits was in men below the age of 30 years. Twelve cases were presented with defects between the MP and PIP joints, four cases with web space defects, and three cases were presented with defects between the PIP joint and DIP joints, only one case was beyond the DIP joint. Quaba and Davison in 1990 have used this flap in 21 cases, 11 of them presented with web space defects or deformities, four with dorsal metacarpal defects, four with dorsal phalangeal defects, and three with distal palmar defects, no flaps beyond the DIP joint was described [3]. Ahmed Mabrouk uses an hourglass design of flap in the reconstruction of web spaces of 25 patients with syndactyly [8].

In our study no flap was lost. Only two flaps suffered from partial distal necrosis due to distal reach of the flap and tension on closure, and were managed by debridement and daily dressing until complete healing by secondary intention. The other 18 flaps healed with primary intension without any noticeable postoperative event. Also two flaps suffered from congestion and were managed conservatively by elevation of the affected limb and release of any tension suture over the pedicle and survived completely. Donor sites were closed directly in all cases, wound dehiscence of the donor site occurred in two cases where the flap width was 3.5 cm, this was managed by daily dressing and healed with secondary intention. We almost used the flaps with a maximal width of 3 cm so that primary closure was feasible. Follow-up of the patient regarding the flap and the donor site showed that the morbidity was minimal with nice esthetic results, only two cases suffered from hypertrophic scars, and three cases with hyperpigmentation.

In Quaba and Davison [3] study, healing by primary intention followed an uneventful postoperative course in 18 cases. In one of these, primary venous microanastomosis was necessary to relieve venous congestion which followed release of the tourniquet. Partial or complete necrosis occurred in the remaining three flaps, all of which were destined to cover defects of the distal palm. Quaba and Davison [3] used a split thickness graft to close donor site in eight patients whose dorsal hand skin was heavily scarred. In the remaining 13 cases, donor sites were closed directly.

In Ahmed Mabrouk study in 2008, a skin graft-free reconstruction has been accomplished in all cases with no problems of flap viability except in three patients in whom partial flap necrosis and sloughing was encountered and managed conservatively and healed with secondary intention. This may be due to tight dressing with compression of the adjacent fingers over the waist of the flap, which leads to necrosis of the distal part of the flap. Scar contractures at the palmar end of the web space have been observed in these three patients during the follow-up. By using a pressure garment and scar-softening agents, further surgical intervention was unnecessary for these patients. During the mean follow-up period (2.5 years), there was no web creeping or recurrence of the deformity in any of the patients [8].

The flap has the advantage of being reliable and easy to raise. The island design and the option of siting the flap on any one of the intermetacarpal spaces increase its territory of cover. It has the usual advantages of a local flap (color match, skin thickness, and texture), which makes it particularly suitable to cover MP and phalangeal defects proximal to the fingertip as well as web defects. However, it should be remembered that the dorsal hand skin may be hair bearing when considering this flap for web in men. Flaps as large as 27 cm 2 have been successfully transposed to cover defects which would otherwise have required regional (reverse forearm) or distant flaps. Donor site morbidity is acceptable. There is minimal interference with postoperative mobilization irrespective of the method of closure of the secondary defect. It is worthwhile considering that more than one flap could be raised at the same time, permitting cover of multiple defects but with significant scar on the dorsum of the hand [3].

The major drawback of the DMAP flap (and all other island flaps from the dorsum of the hand) is that movement of the flap is achieved by twisting of the pedicle. This can lead to kinking and occlusion of the vessels, especially the veins, which are a low-pressure system leading to ischemia or venous congestion. Therefore, it is important to ensure that there is no injury (e.g., contusion to the dorsal skin, previous injection of a local anesthetic, deep laceration extending into the web space, or metacarpal neck or head fracture) in the vicinity of the selected perforator, also secure meticulous hemostasis, and minimize any compression of the flap or the bridge segment [1].

The donor site morbidity of the flap is minimal, as the lax dorsal skin allows primary closure of the donor defect and in most cases scars on the dorsum of the hand settle down well; however, flaps wider than 3 cm may need a full-thickness skin graft for donor site closure [1].

This flap may require division of some sensory branches during elevation. This may result in sensory loss in the territory of the nerve. With extra care, significant branches of the dorsal ulnar and the superficial radial nerves can be spared during elevation. This flap is not sensate. It is usually destined to cover areas where crude sensation is sufficient. There is minimal interference with postoperative mobilization irrespective of the method of closure of the secondary defect ∼2–3 weeks [3].


  Conclusion Top


DMAP flap is a reliable alternative for treating small to moderate sized defects on the dorsum of the hand, soft-tissue defects of the fingers (proximal to the finger tip), web space, and distal palm defects. The flap offers the surgeon a simple and fast procedure to cover defects with minimal donor site morbidity and with preservation of the functional and esthetic outcomes of the hand.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Sebastin SJ, Mendoza RT, Chong AK, Peng YP, Ono S, Chung KC, et al. Application of the dorsal metacarpal artery perforator flap for resurfacing soft-tissue defects proximal to the fingertip. Plast Reconstr Surg 2011; 128:166e–178e.  Back to cited text no. 1
    
2.
Vuppalapati G, Oberlin C, Balakrishnan G. 'Distally based dorsal hand flaps': clinical experience, cadaveric studies and an update. Br J Plast Surg 2004; 57:653–667.  Back to cited text no. 2
    
3.
Quaba A, Davison P. The distally-based dorsal hand flap. Br J Plast Surg 1990; 43:28–39.  Back to cited text no. 3
    
4.
Sebastin SJ, Chung KC. Dorsal metacarpal artery perforator flap. In: Chung KC editor. Hand and wrist surgery (operative techniques). 2nd ed. Philadelphia, Elsevier; 2012; 412–423.  Back to cited text no. 4
    
5.
Maruyama Y. The reverse dorsal metacarpal flap. J Plast Reconstr Aes Surg 1990; 43:24–27.  Back to cited text no. 5
    
6.
Isaraj S. Use of dorsal metacarpal artery flaps in post burn reconstruction, two cases report. Macedonian J Med Sci 2011; 4:180–184.  Back to cited text no. 6
    
7.
Bailey SH, Andry D, Saint-Cyr M. The dorsal metacarpal artery perforator flap: a case report utilizing a quaba flap harvested from a previously skin-grafted area for dorsal 5th digit coverage. Hand 2010; 5:322–325.  Back to cited text no. 7
    
8.
Wafa AMA. Hourglass dorsal metacarpal island flap: a new design for syndactylized web reconstruction. J Hand Surg 2008; 33:905–908.  Back to cited text no. 8
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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