Reconstruction of Forearm Region

(1)

Yotsuya Medical Cube, Chiyoda-ku, Tokyo, Japan

Basic Principles

The proximal area of the forearm is rich with muscle tissue, and in many cases exposed bone or tendons can be covered with muscle tissue, and can normally be covered with a skin graft. If there are doubts about whether a skin graft will take in one stage, it is possible to first place an artificial dermis on the area and then perform skin grafting several weeks later. Therefore, the main cases where the forearm needs to be reconstructed by covering with a skin flap involve the distal half of the forearm where tendons are easily exposed.

The skin of both the medial and lateral side of the distal end of the forearm is thin, and exposure of tendons or bone/nerves are frequently encountered. In such cases it is necessary to cover with a thin flap. It is easier to avoid adhesion of tendons if a skin flap that is rich in adipose tissue with good blood flow is used. Here, there is no need for sensory function. The most practical flap is the abdominal flap, which is used either as a pedicled flap or a free flap, and made thinner by removal of fat.

Selectable Flaps and Surgical Procedures

Rotation flap/radial forearm flapPedicled abdominal flapFree abdominal perforator flapFree groin flapPedicled latissimus dorsi muscle flapFree scapular flapLateral upper arm flap (reverse flow, normal flow)Skin graft and negative pressure wound therapyAnterolateral thigh flap

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.

2.1 Rotation Flap/Radial Forearm Flap (Level of Difficulty: 1)

Information

Vascular pedicle Subcutaneous vascular plexus of forearm or radial artery perforator

Flap size It is possible to move the entire skin of the forearm

Advantage Simple with stable blood flow

Caution The flap is dissected above the proper fascia, and a fascial flap is elevated using the forearm fascia. The skin of the medial forearm can easily be rotated around the transverse axis, however extending it around the vertical axis can lead to contracture.

2.1.1 Operation Procedures

Fig. 2.1

(a, b) Procedure 1: A rotation flap is designed as a measure for moving the skin of the distal medial forearm. Dog ear correction is necessary after rotation of a skin flap at the end

Fig. 2.2

Procedure 2: The distal end of the skin is dissected from above the proper fascia, and the fascial flap containing the forearm fascia moved while being rotated, and the dog ear corrected

2.2 Pedicled Abdominal Flap (Level of Difficulty: 3)

Information

Vascular pedicle Superficial epigastric blood vessels

Flap size A width for which direct closure can be conducted, normally 8–10 cm. Can be made over 25 cm extending from pubic region

Advantage Stable blood flow. Comparatively simple surgical technique. Rich amount of tissue. The tip can be made thinner. By rolling the base of the skin flap and creating a tubed flap, there is no need to include lining for the flap, and because there is no raw surface, the patient can shower from an early stage. By creating a long tubed flap, it is possible to increase the level of freedom of the upper arm, preventing contraction of the shoulder joint

Disadvantage Surgery is conducted in two stages.

2.2.1 Operation Procedures

Fig. 2.3

Procedure 1: A trapezium shaped skin flap is designed on the abdomen region on the same side as the affected hand with either an upper pedicle or lower pedicle (the skin flap can be located anywhere as long as it is designed above the central axis of the lateral abdomen area, so the position of the flap should be determined according to the area that is to be covered by the flap)

Note

A skin flap of at least 8 cm is required in order to create a tubed flap. If sufficient width is not secured at the base of the flap where large amounts of fat are present, the vascular pedicle will be pinched when in the tube state, which can lead to circulation failure, so care is required. The tip of the flap can be made to the required width, however the skin flap is made longer in order to secure greater freedom for the upper arm. Normally length is about double the width.

Refer to Section of

“Reconstruction of dorsum of hand/Pedicled abdominal skin flap” in Chap. 3

Fig. 2.4

Procedure 2: The flap is dissected at the layer above the external oblique muscle. A broad area is dissected from the donor area and sutured closed

Fig. 2.5

Procedure 3: The part of the flap tip to be used for covering the wound is thinned by removing fat, based on the condition of the recipient site. A considerable amount can be removed as long as the subcutaneous vascular plexus is retained

Note

For the area to be used for the tube flap, a large amount of fat is resected around the margin of the flap to ease tubing stress, but care must be taken for resecting excess fat near the superficial epigastric blood vessels.