15018752330
发表时间:2015-12-09 浏览次数:530次
Introduction
Severe crushing injuries to the distal forearm are devastating and can
preclude direct replantation for salvage of the hand. In such difficult
situations, temporary ectopic implantation is a viable option under
specific circumstances. [1]
The amputated part, when transferred to a healthy recipient site,
allows the patient to recover from critical combined injuries, radical
debridement, and related soft tissue repairs. [2]
Previous temporary ectopic implantations have been reported in the literature. Wang et al. [3]
reported two cases of temporary ectopic implantation of complex
amputated forearms, followed by successful replantation to their
anatomic positions in a second stage, the contralateral upper extremity
was an acceptable recipient site for temporary ectopic implantation. For
subsequent replantation, a cross-arm flap was designed to carry the
vascular pedicle from the ectopic implantation recipient to improve
blood supply to the replanted part upon replantation to the original
site and with when the blood supply was re-established. Li et al. [4]
temporarily implanted thumbs ectopically onto the forearm and foot in
two cases, the thumbs survived after second-stage replantation and the
patients regained function 4 months after surgery. Tomlinson et al. [5]
implanted digits to the contralateral forearm, with subsequent
reconstruction of the injured hand when combined with microvascular toe
transfer. Their outcome was a functionally useful hand which could be
incorporated into daily life and a cosmetic appearance preferable to
that of amputation.
This report describes a case of temporary ectopic hand implantation. The left foot was used as the recipient site.
Case report
In May 14, 2010, a 35-year-old man sustained a machine injury to his left forearm [Figure 1].
The patient was consented for this technique. Physical examination
revealed a severe crushing injury that extended from the wrist to the
middle third of the forearm, with contamination and associated
comminuted fractures. The remaining connecting tissues included the
median and ulnar nerves, several flexor tendons, and a strip of skin
with a severe contusion.
Proximal end management
Surgery
was performed under axillary block and epidural anesthesia with
pneumatic tourniquet control. Two surgical teams worked simultaneously.
The limb was transected at the level of the radiocarpal joint [Figure 2]a
and b. The proximal end of the forearm was debrided thoroughly, but was
preserved as long as possible. The median and ulnar nerves were
transected at the distal-most level of the injury site and then turned
proximally into the uninjured subcutaneous tissue. The severely crushed
tendons were debrided. The proximal end of the forearm was sealed with
vacuum drainage.
Hand-to-foot transfer
We selected
the left foot as the ectopic recipient site because of vascular match.
At the dorsum of the left foot, the dorsalis pedis artery was palpated
and assessed using Doppler ultrasound. A dorsalis pedis fasciocutaneous
flap, 7 cm × 8 cm in size, was raised on the dorsum of the foot as a
base for the corresponding defect on the amputated part. The hand was
stabilized to the tarsal bones with K-wires. Anastomoses were performed
between the dorsalis pedis artery and the radial artery, between their
venous counterparts, and between the greater saphenous vein and the
cephalic vein. The skin defect was reconstructed with the dorsalis pedis
fasciocutaneous flap and skin grafts [Figure 2]c
and d. After surgery, the patient was placed in a warm room. The
implanted hand together with the recipient foot was elevated above the
heart level. The patient was given 10 mL/kg dextran 40 twice a day for 7
days. A nurse monitored the color and capillary filling of the hand and
the flap every 2 h. Three weeks after surgery, the patient was allowed
to walk with the bank foot in a specially designed shoe.
Foot-to-forearm transfer
Three months after surgery, the ectopically implant hand was transferred back to the left forearm [Figure 3]a.
The proximal end of the forearm was incised, and the end of the radius
was debrided. The median and ulnar nerves were dissected, and the tendon
ends were prepared. The hand together with the dorsalis pedis
fasciocutaneous flap was incised as a single unit from the recipient
foot [Figure 3]b.
The dorsalis pedis artery, its accompanying veins and great saphenous
vein were dissected proximally until suitable lengths were obtained. The
hand was transferred to the left forearm [Figure 3]c-e.
The radius and carpal bones were fused and stabilized with a plate and
screw system. Anastomoses were performed between the dorsalis pedis
artery and radial artery, between their accompanying veins, and between
the greater saphenous vein and the cephalic vein. The median and ulnar
nerves were repaired directly. We did not repair the radial nerve
because there was a large nerve defect that precluded a direct repair.
Moreover, the radial nerve is less important for hand function. We used
the flexor digitorum superficialis tendons as grafts to repair the
flexor digitorum profundus tendons, extensor and flexor pollicis longus,
and extensor digitorum communis. The wound was then closed. The
secondary defect on the left foot was resurfaced with skin grafts.
Postoperative treatments were similar to the first operation. Four weeks
after surgery, active range-of-motion exercises and physical therapy
were started.
Outcome evaluation
The hand survived with normal color and capillary refilling test, partial flap necrosis was noted, but healed with wound care. Bone healing was achieved 4 months after the second operation. Eighteen months after surgery [Figure 4], two-point discrimination on the pulps of the first through fifth digits was 4, 6, 7, 5, and 8 mm, respectively. Tenolysis was not performed because the patient refused. Tange of motion arcs for the first to fifth metacarpophalangeal joints were 5°, 10°, 4°, 0°, and 3°, respectively; for the proximal interphalangeal joints, 2°, 5°, 2°, 3°, and 0°, respectively; and for the distal interphalangeal joints, 0°, 0°, 2°, 0°, and 0°, respectively. The patient reported no pain for the hand or forearm. The disability score for the arm, shoulder, and hand [6] was 78. Based on a foot function assessment, [7] the patient reported no foot pain and had no difficulty when he stood on tiptoe or walked in the house. The patient had no difficulty when he walked outside for four blocks, climbed or descended stairs, got up from a chair, climbed curbs, ran, or walked quickly.
Discussion
Since the first replant almost 52-year-ago, thousands of severed hands
have been reattached, preserving the quality of life for these patients
through improved function and appearance that the void remaining after
amputation cannot provide. [8]
Revascularization procedures are often easier than replantation, but
incomplete amputations with an extensive crush-avulsion injury may be
more difficult because debridement of nonviable tissue and bone
shortening cannot retain healthy structures. In such cases, the
percentage of viability is lower. Temporary ectopic implantation offers
an approach to detach the distal part safely from the injured site,
which improves subsequent viability. [9]
Several recipient sites are available for temporary ectopic
implantation, including the groin, lower leg, foot, and opposite arm and
hand. [4],[5],[6],[7]
Selection is generally based on matching the vessels between the
recipient site and the implanted part. In our case, a venous network on
the dorsum of the foot was presented, which can be included in the
dorsalis pedis fasciocutaneous flap. In the second-stage foot-to-forearm
transfer, the flap can be transferred to the forearm along with the
hand, without the need for additional vascular anastomosis. In our case,
the flap provided sufficient room for the underlying tendons and
nerves. We believe a groin flap or superficial inferior epigastric
artery flap may be needed in other cases for which a larger space may be
needed to facilitate easier tendon and nerve reconstructions. In
addition, physical therapy of the amputated parts before reattached to
prevent joint stiffness and tendon adhesions, the special needs at the
secondary replantation, such as flaps for the coverage soft tissue
defects at the recipient site and patient acceptance should also be
considered.
Indications for temporary ectopic hand implantation
are severe injuries on the proximal end of the limb where salvation of
the hand in situ is difficult, and the distal part is mildly
injured. Contraindication is severe injured in the distal part where
revascularization is impossible.
Function of the reattached parts
can vary widely. As these are severe and complex injuries, satisfactory
results may not be attained in many patients. In such case, the
inconvenience during the banking period and inappropriateness of shoe
wearing, especially in a cold area, should be considered. In addition,
the cost is generally higher than that of direct replantation or
revascularization. Therefore, the benefits and risks should be discussed
carefully before undertaking these surgical reconstructions.
References
1.Ni G, Wu X, Zhang D, Yang H, Ma X, Sun X. Temporary ectopic implantation of amputated fingers and dorsalis pedis flaps for thumb reconstruction and skin defect repair of hands. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2013;27:1094-7.(in Chinese)
2.Godina M, Bajec J, Baraga A. Salvage of the mutilated upper extremity with temporary ectopic implantation of the undamaged part. Plast Reconstr Surg 1986;78:295-9.
3.Wang JN, Tong ZH, Zhang TH, Wang SY, Zhang HQ, Zhao GQ, Zhang F. Salvage of amputated upper extremities with temporary ectopic implantation followed by replantation at a second stage. J Reconstr Microsurg 2006;22:15-20.
4.Li J, Ni GH, Guo Z, Fan HB, Cong R, Wang Z, Li MQ. Salvage of amputated thumbs by temporary ectopic implantation. Microsurgery 2008;28:559-64.
5.Tomlinson JE, Hassan MS, Kay SP. Temporary ectopic implantation of digits prior to Textreconstruction of a hand without metacarpals. J Plast Reconstr Aesthet Surg 2007;60:856-60.
6.Reichl H, Schütz T, Gabl M, Angermann P, Russe E, Wechselberger G. Hand replantation: differences in functional outcome considering patient age and sociomedical aspects. Handchir Mikrochir Plast Chir 2013;45:344-9.
7.Riskowski JL, Dufour AB, Hagedorn TJ, Hillstrom HJ, Casey VA, Hannan MT. Associations of foot posture and function to lower extremity pain: results from a population-based foot study. Arthritis Care Res (Hoboken) 2013;65:1804-12.
8.Hallock GG. Transient single-digit ectopic implantation. J Reconstr Microsurg 1992;8:309-11.
9.Zheng W, Zheng GQ. Should children who experience traumatic amputations be offered temporary ectopic implantation instead of a prosthesis? MCN Am J Matern Child Nurs 2014;39:6-7.