|Year : 2019 | Volume
| Issue : 3 | Page : 98-103
First dorsal metacarpal artery flap a workhorse for reconstruction of selected small defects of the hand
Shende K Nilesh, Puri Vinita, Patil Chaitanya, Patil Deepak, Palsule Shilpshree
Department of Plastic and Reconstructive Surgery, King Edward Memorial Hospital and Seth G. S. Medical College, Mumbai, Maharashtra, India
|Date of Web Publication||4-Jul-2019|
Dr. Shende K Nilesh
Department of Plastic and Reconstructive Surgery, King Edward Memorial Hospital and Seth G. S. Medical College, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
Background: The first dorsal metacarpal artery (FDMA) flap is used mainly for reconstruction of thumb defects. We share our experience of this flap for various defects of thumb and also its use to cover other defects. Materials and Methods: Case records of 15 patients with FDMA flap between October 2015 and February 2018 at our center were analyzed retrospectively. Data were analyzed for etiology, associated comorbidities, interval between injury and operation, site of defect, harvesting technique, and inclusion of dorsal interossei muscle cuff, complications, donor-site morbidities, and postoperative sensory recovery. Results: Of 15 patients, 13 were male and 2 were female. Eleven patients had a posttraumatic defect, 2 had post-electric burn defect, 1 had a firecracker injury, and 1 had a post snakebite defect. Of 15 patients, 12 patients had thumb defects, 1 patient with defect of first web space, 1 on volar aspect of palm, and 1 on the dorsum of hand over the head of third metacarpal. All patients showed protective sensations and 6 patients with 12-month follow-up showed minimum of 9 mm of two-point discrimination with no donor-site morbidity. Conclusions: The FDMA flap has a constant anatomy, easy dissection, and shows good functional and esthetic results. FDMA flap is the first treatment of choice for defects of the thumb, but it can be used for selected small defects of hand due to its wide arc of rotation.
Keywords: 2 PD, Dorsal metacarpal artery, thumb defects
|How to cite this article:|
Nilesh SK, Vinita P, Chaitanya P, Deepak P, Shilpshree P. First dorsal metacarpal artery flap a workhorse for reconstruction of selected small defects of the hand. Turk J Plast Surg 2019;27:98-103
|How to cite this URL:|
Nilesh SK, Vinita P, Chaitanya P, Deepak P, Shilpshree P. First dorsal metacarpal artery flap a workhorse for reconstruction of selected small defects of the hand. Turk J Plast Surg [serial online] 2019 [cited 2019 Nov 13];27:98-103. Available from: http://www.turkjplastsurg.org/text.asp?2019/27/3/98/262131
| Introduction|| |
The first dorsal metacarpal artery (FDMA) flap is used mainly for reconstruction of thumb defects, although arc of rotation of this flap is wide enough to cover other areas such as two-thirds of the dorsum of hand on radial aspect, dorsal region over proximal phalanx of middle finger, and radial half of palm. The experiences of using FDMA flap to cover various defects of thumb and its extended use to cover other defects are discussed in this study. This flap is based on the neurovascular structures of the FDMA on the dorsum of the proximal phalanx of the index finger. The literature mentions different variations of FDMA flap, one such variation is extended version of FDMA in which skin can be taken from middle phalanx finger as a random extension. Colema in 1961 and Holevich in 1963 were the first to describe this procedure which was later popularized by Lie and Posch. Later, Foucher incorporated neural structures into the composite tissue and termed it kite flap. Selection of the method for thumb reconstruction depends on level of injury, status of the remaining hand, age, occupation, and functional demands of the patient. The options for thumb resurfacing ranges from skin grafting, local flaps such as cross finger flap, FDMA flap, and Littler's neurovascular island flap to free flaps. FDMA flap provides stable sensate soft-tissue cover with minimal donor-site defect and also has wide arc of rotation [Figure 1] and [Figure 2], thus making it a workhorse for selected small defects of hand.
|Figure 1: Arc of rotation of first dorsal metacarpal artery flap for coverage of dorsal defect|
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|Figure 2: Arc of rotation of first dorsal metacarpal artery flap for coverage of volar defect|
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The aims of this study were as follow:
- To evaluate for use of FDMA in different scenarios
- To analyze intraoperative challenges during harvest of FDMA and means to counter them
- To note postoperative complications of FDMA
- To study the advantages of using FDMA flap for thumb reconstruction over its substitutes.
| Materials and Methods|| |
Permission for the study was received from the Ethics Committee of our institute (EC/OA-56/2018). Case records of 15 patients reconstructed with FDMA between October 2015 and February 2018 at our center were scrutinized. Data were collected through operative notes, X-ray films, anesthesia records, admission, outpatient department notes, and notes from occupational therapy department and it was entered in the case record form. The case record form of the patients was analyzed for assessing etiology of injury, associated comorbidities, interval between injury and operation, site of defect, harvesting technique in terms of inclusion of FDMA/second dorsal metacarpal artery (SDMA) vessel, inclusion of dorsal interossei muscle cuff, and complications such as necrosis of flap, donor-site morbidities, and postoperative sensory recovery. Postoperatively patients were assessed by occupational therapy department for sensory recovery in terms of protective sensations by pressure with Semmes–Weinstein monofilament and two-point discrimination.
The patient is operated under plexus block or general anesthesia with arm positioned on the arm table. Under tourniquet, the wound is debrided and defect created. The flap is marked on the dorsal aspect of the index finger over proximal phalanx. The first incision is taken on the dorsum of hand with convexity toward the ulnar side to include SDMA when it is not possible to include FDMA. Incision deepened to expose fascia over dorsal interossei muscle, superficial vein which drains the flap is preserved, and fascial cuts taken to include the FDMA. A cuff of dorsal interossei muscle is harvested along to preserve the integrity of FDMA vessel. The skin island is then raised from distal to proximal direction in the plane above paratenon. Flap is raised till its pivot point which lies between the bases of the first and second metacarpal bone at the tip of the triangular first web space. The literature also supports harvesting of muscle cuff to safeguard the vessel. After raising the flap, the tourniquet is released to assess vascular flow of the flap and the flap is then tunneled into the defect.
| Results|| |
Of 15 patients, 13 were male and 2 were female. Age of patient in this study ranged between 6 and 62 years, with mean age being 27.66 years. Eleven patients had a posttraumatic defect, two had post-electric burn defect, one had a firecracker injury, and one had a post snakebite defect. Thirteen patients were operated within 1 week of injury of which eight were operated within 24 h. The two patients operated after a week suffered from post snakebite defect and post-electric shock defect. Details regarding indications, time of reconstruction, flap sizes, follow-up periods, and sensory recovery of flap have been included in separate [Table 1]. Twelve patients had thumb defects of which seven patients had defects at the tip of thumb [Figure 3], [Figure 4], [Figure 5], two had amputation at proximal phalanx level [Figure 6], two patients had the defect on the dorsum of proximal phalanx, and one had amputation at the level interphalangeal joint [Figure 7]. The other three patients had the defect of first web space, defect on volar aspect of palm [Figure 8], and defect on the dorsum of hand over the head of third metacarpal [Figure 9], [Figure 10], [Figure 11], [Figure 12]. All flaps were harvested from skin on the dorsum of index finger over the proximal phalanx; extended version of FDMA was not used as maximum defect size was less than the standard extent of flap. Of the first five cases, one showed complete necrosis [Figure 10] and [Figure 13] and two others had superficial changes which resolved over a period of time and flaps survived. Hence, muscle cuff of the first dorsal interossei muscle was included during harvest in all but the first five cases. All the cases which had problem of necrosis were because of arterial insufficiency probably due to injury while harvest or due to anatomical variation, thus we started including muscle cuff to safeguard the vessel and to visualized at least one branch of FDMA while harvesting the flap after initial five cases. We lost one flap but the other two flaps survived which should superficial changes as they resolved spontaneously over period of 2 weeks without any intervention. SDMA was included in one case along with FDMA in the case of defect on dorsum of proximal phalanx [Figure 14] and [Figure 15]. Maximum follow-up was 12 months and minimum follow-up was 1 month with mean follow-up period of 6.8 months. All patients showed protective sensations and six patients with 12-month follow-up showed minimum of 9 mm of two-point discrimination. No patient had functional donor-site morbidity. There was no restriction of movement at metacarpophalangeal joint of index finger and no graft loss.
|Table 1: Mentioning case number, etiology of defects, the indications, time of reconstruction, flap sizes, follow-up, and sensory recovery|
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|Figure 8: Volar defect between distal palmar crease and proximal digital crease|
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|Figure 9: Post-electric burn defect over the head of third metacarpal preoperative|
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|Figure 12: First dorsal metacarpal artery flap cover for the head of third metacarpal postoperative|
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|Figure 14: First dorsal metacarpal artery flap with the second dorsal metacarpal artery for defect on dorsum of proximal phalanx intraoperative|
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|Figure 15: First dorsal metacarpal artery flap with second dorsal metacarpal artery for defect on dorsum of proximal phalanx postoperative|
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| Discussion|| |
The FDMA flap is required for thumb defects when there is deficiency of locally available tissue and if tendon or bone is exposed. FDMA flap helps in preservation of length of thumb and provides sensibility. The options for thumb defect reconstruction depend on the amount and type of tissue lost; and it ranges from secondary intention healing, skin grafts to local flaps such as cross-finger flaps, Litter neurovascular island flap, and FDMA flap to free tissue transfer. Contraindications of FDMA flap include circular defects at the proximal or distal phalanx and previous injury at the second metacarpal level. Thus, in cases of traumatic injury to the thumb, radiographs should be obtained to determine the presence of fracture.
In early cases, we had the problem of partial to complete necrosis of the flap which could be due to missing of branch of FDMA or traumatic injury to vessel during harvest because of anatomical variations. The literature regarding the arterial anatomy of the dorsal aspect of the hand shows some divergences concerning the presence and the constancy of DMAs and their relationships with the palmar arterial system. The anatomic study of the dorsal arterial system of the hand by de Rezende et al. shows that the radial artery divides into three branches at the level of the anatomic snuffbox: the princeps pollicis artery, the FDMA, and the branch to the deep palmar arch in 84.6% cases, but in 15.3% of cases, a fourth branch running to the dorsoulnar aspect of the thumb was observed. Hamdy observed the division of FDMA into three branches. Based on the variations of its course and branching pattern, de Rezende et al. strongly suggested that to be certain to include the FDMA, the fasciocutaneous pedicled flap based on the FDMA must be raised in the subfascial plane, including a strip of the interossei muscle fascia with the pedicle. As we went through our learning curve, the results improved probably due to better understanding of anatomical variations and strategic visualization of at least one branch of FDMA and harvesting cuff of muscle to safeguard the vessel. We were also able to extend the use of FDMA flap utilizing its wide arc of rotation to cover defects on volar aspect of palm and in covering the head of third metacarpal. There are few references in literature where FDMA was used for coverage of defects other than thumb, such as palmar defects after release of Dupuytren's contracture and the radial aspect of the index finger., The rich variation of branching pattern and termination of radial artery is not only of academic interest but also useful to surgeons as these variations in the vascular anatomy offer the operating surgeon a wide range of flexibility while harvesting flaps. Thus, we can get numerous flaps harvested based on this vascular system. The different variations mentioned in literature are either to increase the reach of flap or to increase the size of the flap that can be raised.,,,
All flaps in our cases were harvested from skin on the dorsum of index finger over proximal phalanx. An extended version of FDMA in which skin can be taken from middle phalanx finger as a random extension because of the existence of the rich dermal–subdermal plexus supplying the dorsal skin of both segments was not used as maximum defect size was less than the standard extent of flap. There are also references which suggest including of SDMA in the flap when FDMA cannot be used. In our study, SDMA was included in one case along with FDMA in the case of defect on the dorsum of proximal phalanx. It was done in this case as the SDMA was bigger in size and the defect was proximal enough and hence sacrificing of the FDMA was not required for increasing the reach of the flap.
With respect to sensations, Muyldermans and Hierner showed in their study complete reorientation in only one patient and incomplete reorientation in six patients. However, it was not disturbing and did not interfere with daily activities. This can be corrected surgically with a technique called a de × branchement–re × branchement by Foucherin which the divided nerve of the transferred island flap is sutured to the original nerve of the thumb. In our cases, we did not coaptate nerve in the flap to that of the thumb. The two-point discrimination test is the most frequently used test for the assessment of sensory outcome after nerve repair. Various studies in which FDMA flap was used showed the two-point discrimination in a range of 6–14 mm.,, All patients in our study showed protective sensations and six patients with 12-month follow-up showed minimum of 9 mm of two-point discrimination.
No patient had donor-site morbidity as meticulous attention was paid during harvesting so as to not injure the paratenon and also to graft application and immobilization.
| Conclusions|| |
The harvesting of FDMA flap has a learning curve in itself due to anatomical variations, but results can be improved by thorough anatomical knowledge and refinement in surgical techniques such as strategic visualization of FDMA, harvesting a cuff of muscle to safeguard the vessel, and inclusion of SDMA if situation demands. FDMA flap shows good functional results with low donor-site morbidity. Although FDMA flap is the first treatment of choice for defects of the thumb, it can be used for selected small defects of hand due to its wide arc of rotation.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14], [Figure 15]