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Hand Surgery, Vol. 18, No. 2 (2013) 277281 © World Scientific Publishing Company DOI: 10.1142/S0218810413720209
BIPEDICLED HOMODIGITAL NEUROVASCULAR ISLAND FLAP FOR RESURFACING DORSAL DIGITAL DEFECTS AMPUTATION
Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
Tun Lin Foo,* E. M. Chew† and M. Arul* *Hand
and Microsurgery Section Department of Orthopaedic Surgery Tan Tock Seng Hospital, Singapore 308433 †
Department of Hand Surgery Singapore General Hospital, Singapore 169608 Received 11 October 2012; Revised 7 December 2012; Accepted 10 December 2012 ABSTRACT Critical defects distal to the proximal interphalangeal joint are usually treated by heterodigital or reverse-flow homodigital flaps. Drawbacks of the former are potential donor digit stiffness and scarring, while the latter might be complicated by flap congestion. A bipedicled neurovascular island transposition flap design that preserves both proximal and distal extent of digital nerve and artery was employed to treat critical dorsal skin defect in two patients with encouraging results. Technical details and cadaveric study concepts are presented. Keywords: Neurovascular Island Flap; Finger Defects; Finger Reconstruction.
INTRODUCTION
availability is determined by patency of collateral digital circulation and palmar digital arch. Potential complications of retrograde flow vascular island flaps are flap congestion or pulp paresthesia due to injury to vena comitantes or digital nerve during flap dissection. We postulated that a neurovascular island transposition flap that preserves both proximal and distal ends of the digital nerve and artery could resurface dorsal defects without compromising distal circulation or sensation. Proximal mobilization of neurovascular bundle provides 10 mm or more of longitudinal excursion. In contrast, distal neurovascular mobilisation and
Treatment of dorsal skin defects of the finger distal to the proximal interphalangeal joint (PIPJ) is challenging due to limited skin availability and mobility. Small non-critical defects can be treated with skin grafts or local advancement flaps whereas larger defects exposing bone, joint, or denuded tendon require flap coverage such as reverse cross finger, homodigital or heterodigital vascular island flaps.15 With homodigital flap reconstruction, donor morbidity is confined to the injured digit. However, the choice is usually based on retrograde flow vascular island design,3 and its
Correspondence to: Dr. Tun-Lin Foo, Hand and Microsurgery Section, Department of Orthopaedic Surgery, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433. Tel. (þ65) 6357-7597, Fax: (þ65) 6357-7715, E-mail: [email protected] Financial disclosure/conflict of interest: none 277
June 25, 2013
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Fig. 1 Cadaveric study of flap concept. Left to right: 7 16 mm skin defect created over the dorsum of middle phalanx. Digital nerve (yellow arrow) and artery (red arrow) mobilised proximally and distally. Terminal branches of digital nerve and artery skeletonised to allow dorsal transposition of flap. Flap transposed dorsally and full thickness skin graft inset onto palmar donor site.
gain in horizontal excursion is not known. From our cadaveric studies, we found that up dorsal excursion is possible with mobilisation of terminal branches of digital nerve and artery (Fig. 1). Two patients with critical skin defects over the dorsum of the middle phalanx were treated with neurovascular island transposition flaps based on the aforementioned bipedicled design with encouraging results. The technique and case details are discussed.
TECHNIQUE A template of the flap was outlined along the neurovascular axis. Under loupe magnification and tourniquet control, a proximal incision was made to identify and mobilise the neurovascular bundle. Next, an incision was made distally to expose the terminal branches of digital nerve and artery. Vertical fibres tethering these structures were incised to mobilize them for transposition. Then, the flap incision was made and deepened and the flap was elevated through the supraretinacular plane from palmar to dorsal (Fig. 2). The
neurovascular bundle was mobilised from metacarpophalangeal joint to distal interphalangeal joint to allow dorsal transposition and flap inset. The contingency plans to increase flap range were further mobilisation of the proximal extent of the neurovascular bundle or conversion to an antegrade or retrograde vascular island design by separating the nerve from the artery.3 The latter would only be undertaken after a digital Allen test has been performed. Donor defect was covered with full thickness skin graft, bolstered with cotton wool. Dressings were maintained for a week and therapy was initiated thereafter.
RESULTS Case 1: A 27-year-old forklift operator involved in a motorcycle accident sustained an open dislocation of his right small finger distal interphalangeal joint (DIPJ) with extensor tendon loss and critical skin defect over the DIPJ measuring 20 10 mm. He underwent DIPJ fusion with a lag screw and the defect was covered with a radial based transposition flap performed in the manner described above (Fig. 3). At two weeks, pulp sensation
June 25, 2013
9:41:11am
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1372020
Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
Bipedicled Homodigital Neurovascular Island Flap for Resurfacing Dorsal Digital Defects Amputation
279
Fig. 2 Proximal incision (1) is made to expose and mobilize neurovascular bundle. Terminal branches of digital nerve (yellow) and artery (red) are mobilised through a distal incision (2). Flap incision (3) is completed and neurovascular bundle is mobilised to allow dorsal transposition and flap inset to cover the defect (shaded area).
Fig. 3 Left to right: Open dislocation of small finger DIPJ with skin and extensor tendon loss, before and after joint fusion with interfragmentary screw. Neurovascular island flap based on radial neurovascular bundle transposed dorsally to cover dorsal defect. Skin graft inset to palmar donor site and bolstered with cotton wool.
was normal and two-point discrimination (2PD) was 4 mm. He resumed his baseline vocation eight weeks after surgery. Flap and donor site healed uneventfully with satisfactory appearance. There was mild scar contracture that restricted PIPJ motion from 15 to 90 degrees (Fig. 4).
Case 2: A 35-year-old cook with a 10 25 mm dorsal skin defect over the PIPJ exposing extensor tendon after three debridements for dorsal subcutaneous abscess of his middle finger (Fig. 5). The unhealthy state of the tendon precluded the use of skin graft, while prior dissection near the dorsal
June 25, 2013
9:41:14am
Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
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Fig. 4
Left to right: Arthrodesis united. Appearance of flap at three months.
Fig. 5 Left to right: Dorsal skin defect as a result of infection exposing unhealthy tendon. Bipedicled neurovascular island flap transposed dorsally to cover the defect.
metacarpal artery (DMCA) precluded the use of DMCA perforator based flap. He was treated with a transposition flap based on the aforementioned design based on the radial neurovascular bundle. Flap and donor site healing were uneventful and he resumed his job four weeks after surgery
(Fig. 6). During follow-up three months postoperatively, pulp sensation was normal and 2PD was 4 mm. Active motion at PIPJ was 30 to 100 degrees. Non-compliance to therapy, secondary scar and skin graft contraction were possible reasons for the contracture.
June 25, 2013
9:41:19am
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Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
Bipedicled Homodigital Neurovascular Island Flap for Resurfacing Dorsal Digital Defects Amputation
Fig. 6
281
Left to right: Dorsal, radial, and palmar aspect of the reconstructed digit at three months.
DISCUSSION Bipedicled neurovascular island flaps and distal digital nerve/ artery mobilization received scant attention as most flaps are tailored to treat fingertip defects.6,7 Although limited in clinical application, this concept is advantageous in selected clinical scenario such as those reported because complications associated with heterodigital or retrograde flow homodigital flaps can potentially be avoided. This flap design is indicated for critical defects exposing bare extensor tendon, joint, or bone, unsuitable for skin grafts. Dorsal defects up to 10 mm wide can be covered with this transposition flap as this was the upper limit of flap mobilisation without dividing either end of the neurovascular bundle. Contraindications include vascular embarrassment of donor artery or fingertip crush injury. The advantages of this flap are preservation of pulp sensation, and relative ease of harvesting. Outcomes of our clinical cases show that mobilisation of terminal branches of digital nerve and artery can increase flap mobility without causing clinically detectable neurapraxia. Its homodigital design and antegrade flow avoid adjacent digit donor morbidity and potential flap congestion, respectively. Further application of the concept of distal neurovascular mobilisation includes the potential to design distally based flaps for reconstruction of eponychial defects.
The drawbacks of the flap are the limited reach due to preservation neurovascular bundle, and potential palmar donor site morbidity. Placing zigzag incision instead of linear incisions may avert flexion contracture of interphalangeal joints. In conclusion, this flap is a useful addition to the current armamentarium of homodigital flap options for finger defect reconstruction that does not impair donor digit function and relatively easy to harvest.
References 1. Atasoy E, Reversed cross-finger subcutaneous flap, J Hand Surg Am 7A:481483, 1982. 2. Teoh LC, Tay SC, Yong FC, Tan SH, Khoo DBA, Heterodigital arterialized flaps for large finger wounds: results and indications, Plast Reconstr Surg 111:19051913, 2003. 3. Kojima T, Tsuchida Y, Hirase Y, Endo T, Reverse vascular pedicle digital island flap, Br J Plast Surg 43:290295, 1990. 4. Voche P, Merle M, The homodigital subcutaneous flap for cover of dorsal finger defects, Br J Plast Surg 47:435439, 1994. 5. Gurdin M, Pangman JW, The repair of surface defects of fingers by transdigital flaps, Plast Reconstr Surg 5:368371, 1946. 6. Venkataswami R, Subramaniam N, Oblique triangular flap: a new method of repair for oblique amputations of the fingertip and thumb, Plast Reconstr Surg 66:296300, 1980. 7. Foucher G, Khouri RK, Digital reconstruction with island flaps, Clin Plast Surg 24:132, 1997.
9:40:58am
WSPC/135-HS
FA1
1372020
Hand Surgery, Vol. 18, No. 2 (2013) 277281 © World Scientific Publishing Company DOI: 10.1142/S0218810413720209
BIPEDICLED HOMODIGITAL NEUROVASCULAR ISLAND FLAP FOR RESURFACING DORSAL DIGITAL DEFECTS AMPUTATION
Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
Tun Lin Foo,* E. M. Chew† and M. Arul* *Hand
and Microsurgery Section Department of Orthopaedic Surgery Tan Tock Seng Hospital, Singapore 308433 †
Department of Hand Surgery Singapore General Hospital, Singapore 169608 Received 11 October 2012; Revised 7 December 2012; Accepted 10 December 2012 ABSTRACT Critical defects distal to the proximal interphalangeal joint are usually treated by heterodigital or reverse-flow homodigital flaps. Drawbacks of the former are potential donor digit stiffness and scarring, while the latter might be complicated by flap congestion. A bipedicled neurovascular island transposition flap design that preserves both proximal and distal extent of digital nerve and artery was employed to treat critical dorsal skin defect in two patients with encouraging results. Technical details and cadaveric study concepts are presented. Keywords: Neurovascular Island Flap; Finger Defects; Finger Reconstruction.
INTRODUCTION
availability is determined by patency of collateral digital circulation and palmar digital arch. Potential complications of retrograde flow vascular island flaps are flap congestion or pulp paresthesia due to injury to vena comitantes or digital nerve during flap dissection. We postulated that a neurovascular island transposition flap that preserves both proximal and distal ends of the digital nerve and artery could resurface dorsal defects without compromising distal circulation or sensation. Proximal mobilization of neurovascular bundle provides 10 mm or more of longitudinal excursion. In contrast, distal neurovascular mobilisation and
Treatment of dorsal skin defects of the finger distal to the proximal interphalangeal joint (PIPJ) is challenging due to limited skin availability and mobility. Small non-critical defects can be treated with skin grafts or local advancement flaps whereas larger defects exposing bone, joint, or denuded tendon require flap coverage such as reverse cross finger, homodigital or heterodigital vascular island flaps.15 With homodigital flap reconstruction, donor morbidity is confined to the injured digit. However, the choice is usually based on retrograde flow vascular island design,3 and its
Correspondence to: Dr. Tun-Lin Foo, Hand and Microsurgery Section, Department of Orthopaedic Surgery, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433. Tel. (þ65) 6357-7597, Fax: (þ65) 6357-7715, E-mail: [email protected] Financial disclosure/conflict of interest: none 277
June 25, 2013
9:40:59am
Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
278
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T. L. Foo, E. M. Chew & M. Arul
Fig. 1 Cadaveric study of flap concept. Left to right: 7 16 mm skin defect created over the dorsum of middle phalanx. Digital nerve (yellow arrow) and artery (red arrow) mobilised proximally and distally. Terminal branches of digital nerve and artery skeletonised to allow dorsal transposition of flap. Flap transposed dorsally and full thickness skin graft inset onto palmar donor site.
gain in horizontal excursion is not known. From our cadaveric studies, we found that up dorsal excursion is possible with mobilisation of terminal branches of digital nerve and artery (Fig. 1). Two patients with critical skin defects over the dorsum of the middle phalanx were treated with neurovascular island transposition flaps based on the aforementioned bipedicled design with encouraging results. The technique and case details are discussed.
TECHNIQUE A template of the flap was outlined along the neurovascular axis. Under loupe magnification and tourniquet control, a proximal incision was made to identify and mobilise the neurovascular bundle. Next, an incision was made distally to expose the terminal branches of digital nerve and artery. Vertical fibres tethering these structures were incised to mobilize them for transposition. Then, the flap incision was made and deepened and the flap was elevated through the supraretinacular plane from palmar to dorsal (Fig. 2). The
neurovascular bundle was mobilised from metacarpophalangeal joint to distal interphalangeal joint to allow dorsal transposition and flap inset. The contingency plans to increase flap range were further mobilisation of the proximal extent of the neurovascular bundle or conversion to an antegrade or retrograde vascular island design by separating the nerve from the artery.3 The latter would only be undertaken after a digital Allen test has been performed. Donor defect was covered with full thickness skin graft, bolstered with cotton wool. Dressings were maintained for a week and therapy was initiated thereafter.
RESULTS Case 1: A 27-year-old forklift operator involved in a motorcycle accident sustained an open dislocation of his right small finger distal interphalangeal joint (DIPJ) with extensor tendon loss and critical skin defect over the DIPJ measuring 20 10 mm. He underwent DIPJ fusion with a lag screw and the defect was covered with a radial based transposition flap performed in the manner described above (Fig. 3). At two weeks, pulp sensation
June 25, 2013
9:41:11am
WSPC/135-HS
FA1
1372020
Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
Bipedicled Homodigital Neurovascular Island Flap for Resurfacing Dorsal Digital Defects Amputation
279
Fig. 2 Proximal incision (1) is made to expose and mobilize neurovascular bundle. Terminal branches of digital nerve (yellow) and artery (red) are mobilised through a distal incision (2). Flap incision (3) is completed and neurovascular bundle is mobilised to allow dorsal transposition and flap inset to cover the defect (shaded area).
Fig. 3 Left to right: Open dislocation of small finger DIPJ with skin and extensor tendon loss, before and after joint fusion with interfragmentary screw. Neurovascular island flap based on radial neurovascular bundle transposed dorsally to cover dorsal defect. Skin graft inset to palmar donor site and bolstered with cotton wool.
was normal and two-point discrimination (2PD) was 4 mm. He resumed his baseline vocation eight weeks after surgery. Flap and donor site healed uneventfully with satisfactory appearance. There was mild scar contracture that restricted PIPJ motion from 15 to 90 degrees (Fig. 4).
Case 2: A 35-year-old cook with a 10 25 mm dorsal skin defect over the PIPJ exposing extensor tendon after three debridements for dorsal subcutaneous abscess of his middle finger (Fig. 5). The unhealthy state of the tendon precluded the use of skin graft, while prior dissection near the dorsal
June 25, 2013
9:41:14am
Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
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Fig. 4
Left to right: Arthrodesis united. Appearance of flap at three months.
Fig. 5 Left to right: Dorsal skin defect as a result of infection exposing unhealthy tendon. Bipedicled neurovascular island flap transposed dorsally to cover the defect.
metacarpal artery (DMCA) precluded the use of DMCA perforator based flap. He was treated with a transposition flap based on the aforementioned design based on the radial neurovascular bundle. Flap and donor site healing were uneventful and he resumed his job four weeks after surgery
(Fig. 6). During follow-up three months postoperatively, pulp sensation was normal and 2PD was 4 mm. Active motion at PIPJ was 30 to 100 degrees. Non-compliance to therapy, secondary scar and skin graft contraction were possible reasons for the contracture.
June 25, 2013
9:41:19am
WSPC/135-HS
FA1
1372020
Hand Surg. 2013.18:277-281. Downloaded from www.worldscientific.com by UNIVERSITY OF NEW ENGLAND LIBRARIES on 01/15/15. For personal use only.
Bipedicled Homodigital Neurovascular Island Flap for Resurfacing Dorsal Digital Defects Amputation
Fig. 6
281
Left to right: Dorsal, radial, and palmar aspect of the reconstructed digit at three months.
DISCUSSION Bipedicled neurovascular island flaps and distal digital nerve/ artery mobilization received scant attention as most flaps are tailored to treat fingertip defects.6,7 Although limited in clinical application, this concept is advantageous in selected clinical scenario such as those reported because complications associated with heterodigital or retrograde flow homodigital flaps can potentially be avoided. This flap design is indicated for critical defects exposing bare extensor tendon, joint, or bone, unsuitable for skin grafts. Dorsal defects up to 10 mm wide can be covered with this transposition flap as this was the upper limit of flap mobilisation without dividing either end of the neurovascular bundle. Contraindications include vascular embarrassment of donor artery or fingertip crush injury. The advantages of this flap are preservation of pulp sensation, and relative ease of harvesting. Outcomes of our clinical cases show that mobilisation of terminal branches of digital nerve and artery can increase flap mobility without causing clinically detectable neurapraxia. Its homodigital design and antegrade flow avoid adjacent digit donor morbidity and potential flap congestion, respectively. Further application of the concept of distal neurovascular mobilisation includes the potential to design distally based flaps for reconstruction of eponychial defects.
The drawbacks of the flap are the limited reach due to preservation neurovascular bundle, and potential palmar donor site morbidity. Placing zigzag incision instead of linear incisions may avert flexion contracture of interphalangeal joints. In conclusion, this flap is a useful addition to the current armamentarium of homodigital flap options for finger defect reconstruction that does not impair donor digit function and relatively easy to harvest.
References 1. Atasoy E, Reversed cross-finger subcutaneous flap, J Hand Surg Am 7A:481483, 1982. 2. Teoh LC, Tay SC, Yong FC, Tan SH, Khoo DBA, Heterodigital arterialized flaps for large finger wounds: results and indications, Plast Reconstr Surg 111:19051913, 2003. 3. Kojima T, Tsuchida Y, Hirase Y, Endo T, Reverse vascular pedicle digital island flap, Br J Plast Surg 43:290295, 1990. 4. Voche P, Merle M, The homodigital subcutaneous flap for cover of dorsal finger defects, Br J Plast Surg 47:435439, 1994. 5. Gurdin M, Pangman JW, The repair of surface defects of fingers by transdigital flaps, Plast Reconstr Surg 5:368371, 1946. 6. Venkataswami R, Subramaniam N, Oblique triangular flap: a new method of repair for oblique amputations of the fingertip and thumb, Plast Reconstr Surg 66:296300, 1980. 7. Foucher G, Khouri RK, Digital reconstruction with island flaps, Clin Plast Surg 24:132, 1997.
