(1)
Yotsuya Medical Cube, Chiyoda-ku, Tokyo, Japan
Basic Principles
- 1.
Amputation level of thumb
- 2.
Clinical Principles of Thumb Reconstruction
- (a)
- (b)
Distal phalanx amputation (including IP joint amputation)
Wrap-around flap (+ volar flap)
(Refer to Chap. 10)
- (c)
Basal phalanx amputation (distal to MP joint)
Great toe transfer
Twisted wrap-around flap (TWA) flap
- (d)
Metacarpal level amputation (loss of MP joint)
Second toe transfer
Pollicizatione.
- (e)
- (a)
- 3.
Clinical Principles of Finger Reconstruction
- (a)
Nail bed level amputation (nail matrix intact)
(Refer to Chap. 10)
Split-thickness nail bed graft and digital artery flap (+ distal phalanx bone graft from second toe)
Vascularized nail bed graft (with bone)
- (b)
- (a)
The difficulty level of each surgical procedure is shown subsequent to the procedure title (e.g., Level of Difficulty: 2). The levels range from 1 to 5, with level 1 indicating a preliminary level and level 5 indicating a very advanced level.
9.1 Thumb Amputation at Basal Phalanx Level: Twisted Wrap-Around (TWA) Flap (Level of Difficulty: 5)
Information
Vascular pedicle For the artery, either the first dorsal metatarsal artery or plantar metatarsal artery is used. One subcutaneous vein and one digital toe nerve are attached separately to both wrap-around flaps.
Size As far as possible, inclusion of skin from weight-bearing areas is avoided, using the skin from the dorsum of the toe and first web space skin. Bone is harvested using lateral 1/3 of distal phalanx of great toe attached to flap.
Caution The artery for the two wrap-around flaps comes from the dorsal metatarsal artery or plantar metatarsal artery. It is possible to dissect the vein up to the proximal position, and elevate the flap using one vein, but this can lead to complicated twisting of the artery and the vein when combining the two flaps after transfer, and subsequent problems with circulation. Therefore one subcutaneous vein is harvested for each flap.
9.1.1 Operation Procedures
Fig. 9.1
Procedure 1: Replantation surgery on incomplete amputation of thumb was unsuccessful, however tendon and bone remained intact. Arthrodesis of IP joint conducted
Fig. 9.2
(a, b) Procedure 2: A WA (wrap-around) flap is designed from both the great and second toes. The nail is included in the flap harvested from the great toe. On the planter side of the toe, harvesting of skin flaps from weight-bearing areas is avoided, with skin harvested directly above the plantar digital artery/plantar digital nerve
Fig. 9.3
Procedure 3: Bone is harvested in the nail flap with the lateral 1/3 of the distal phalanx of the great toe attached. The blood vessels/nerves of the two skin flaps are dissected with as little fat attached as possible
Refer to Section of “Extended Twisted Wrap-around (TWA) Flap” in Chap. 4 and Section of “Fingernail Reconstruction: Twisted Wrap-Around (TWA) Flap” in Chap. 10
Note
If the skin flap is harvested with excess fat still attached to the first web space, fat can apply pressure to the blood vessels when two flaps are combined, causing a vascular disturbance. The flaps are elevated with as little fat attached as possible.
Fig. 9.4
Procedure 4: The dorsal metatarsal artery and the plantar metatarsal artery are used for the arterial pedicle
Fig. 9.5
Procedure 5: The nail and bone within the flap is wired to the distal phalanx of the recipient site, and after anastomosis of the dorsal metatarsal artery with the radial artery distal to the snuff box, an additional anastomosis is performed between the plantar metatarsal artery and the ulnar digital artery on the volar side
Fig. 9.6
(a, b) Procedure 6: Anastomosis of the subcutaneous vein is performed separately for each flap. The digital toe nerve included in each of the flaps is sutured to the digital nerve on both sides. Appearance immediately after surgery
Tips
Combine with the dorsal pedis flap for a larger TWA flap.
It is possible to cover an even larger area if creating an extended TWA flap that combines the TWA flap with the dorsal pedis flap.
Photo shows the before and after pictures of a whole thumb reconstruction using an extended TWA flap.
Tips
If reconstructing the donor site area in one stage, elevation of the reverse vascular pedicled extensor digitorum brevis (EDB) muscle flap and conducting a skin graft is also an option.
As a simple dressing procedure of the donor site area, an artificial dermis can be temporarily applied and then a skin graft conducted onto the granulation tissue. However, if wanting to complete the reconstruction in one stage, there is the option of extending the skin incision to the dorsal pedis, elevating the reverse vascular pedicled EDB muscle flap, covering the exposed bone of the great toe and then conducting a skin graft there. The communicating branch between the dorsal pedis artery and the plantar artery system must remain intact in order to carry out this procedure.
