Simultaneous Revascularization and Coverage of a Complex Volar Hand Blast Injury: Case Report Using a Contralateral Radial Forearm Flow-through Flap

Military Medicine, Aug 2008 by Grewal, Navanjun S, Kumar, Anand R, Onsgard, Christina K, Taylor, Bruce J

ABSTRACT War wounds have created a unique reconstructive challenge for successful functional limb salvage. Various injury patterns related to improvised explosive devices (IEDs) occur and proper reconstruction goes a long way in reducing subsequent disfigurement and morbidity. One case in which a contralateral radial forearm flow-through flap is used for simultaneous revascularization and coverage of an IED hand blast injury is described. The advantages of this flap was its consistent arterial anatomy and long vascular pedicle. The thin skin paddle was used for soft tissue coverage of flexor tendon repair, median and ulnar nerve reconstruction, and metacarpal bone open reduction and internal fixation (ORIF). Recovery of motor function was satisfactory.

INTRODUCTION

Complex wounds sustained from improvised explosive devices (IEDs) encountered routinely during Operation Iraqi Freedom have remained a significant challenge for successful functional limb salvage. The tripartite nature of close proximity explosive injury includes blast, fragmentary, and thermal components. Wounds created by IEDs are therefore unique and unlike standard high-velocity penetrating missile injury. Modern microsurgery techniques have revolutionized limb salvage. Before microvascular-free tissue transfer, limb salvage with pedicled flaps did not allow for early motion or complex simultaneous osseous or nerve reconstruction.1,2 We present the successful management of a complex volar hand blast injury with large segmental ulnar artery loss, large segmental median and ulnar nerve loss about the wrist, open metacarpal fractures, and extensive soft tissue loss using a contralateral-free radial forearm flow-through flap. This type of vascular reconstruction not only restores antegrade hand perfusion but also provides excellent coverage of underlying tendon, nerve, and bone reconstructions and facilitates future tendon transfers. Successful reconstruction of improvised explosive device-related war wounds using flow-through flaps and one-stage osseous and neural reconstruction has not been reported.

CASE REPORT

A 26-year-old active duty USMC Sergeant sustained significant left retinal injury and left volar hand injury after detonation of an IED within a HMMWV (High-Mobility Multipurpose Wheeled Vehicle, e.g., Humvee) convoy. After initial stabilization in theater, he was transferred to the National Naval Medical Centre, Bethesda, MD. Written informed consent was obtained from each patient according to the policies of the institutional review board at our institution.

Upon presentation, he had a large volar distal forearm and proximal hand wound with an 8-cm segmental loss of his median nerve and ulnar nerve about the wrist (Fig. 1). His flexor tendons were intact but injured from the blast. The small finger and ring finger metacarpals were fractured. Arteriograms of the upper extremities revealed segmental ulnar artery loss across the wrist on the injured hand. The contralateral upper limb was without injury but a persistent median artery was identified on this examination.

After serial debridements and vacuum-assisted wound therapy, he underwent definitive fracture management with open reduction and internal fixation. The median nerve and ulnar nerve were reconstructed with reversed sural nerve grafts at the time of flap inset and revascularization (Fig. 2). On postinjury day 9, the complex wound was reconstructed with a contralateral-free radial forearm flow-through flap (Fig. 3).

Aggressive hand therapy was instituted with the initiation of controlled finger motion on postoperative day 5 and both donor and recipient arms/hands have regained full finger motion. His postoperative course was unremarkable (Fig. 4). Normal finger pressures and wave forms were present at 7 months after injury and duplex ultrasound evaluation confirmed antegrade flow across the flap into the superficial palmar arch. The thenar musculature did not reinnervate and an extensor indicis proprius opponensplasty was performed 7 months after injury (Fig. 5) for thumb opposition reconstruction. At 15 months, the reconstructed hand regained M4 interrossei function. Temperature sensation and static twopoint discrimination at 8 mm were documented at 15 months.

DISCUSSION

The radial forearm-free flap was first introduced by Yang et al.3 in 1981 and later modified to a flow-through variant by Foucher et al.4 in 1984. Since these early reports, others have described simultaneous vascular and wound reconstruction using flow-through flaps.5-7 The rectus abominus flap, anterolateral thigh flap, temporoparietal fascial flap, and oseocutaneous fibula flap have all been used as a flow-through variant with success. Celikoz et al.8 reported military wound reconstruction using free flaps. Both authors have reported the use of free tissue transfer for wound reconstruction of the upper and lower extremity but failure rates have been higher than those reported for civilian wound reconstruction. Despite these reports, little is known or published regarding the use of free tissue transfer for wound reconstruction caused by IEDs.9