How to perform a fasciotomy of the forearm

Volar Skin Incision

The goal is to gain access to the underlying antebrachial fascia for decompression while minimizing the risk of damage to surrounding nerves and vessels.

1. Using a scalpel, begin the incision at the distal end of the planned line at the carpal tunnel. Make sure to cut only through the skin at this point to prevent unnecessary damage to the underlying structures.

2. Follow the planned markings, curving first ulnarly, then radially to the mobile wad area, and finish the incision at the medial epicondyle.

3. Cauterize bleeding vessels in and immediately below the skin.

Releasing the Carpal Tunnel

The goal is to release the transverse carpal ligament to decompress the carpal tunnel and relieve pressure on the median nerve. For a more thorough guide of this step, see our Carpal tunnel release content.

1. Using a scalpel, carefully incise the palmar aponeurosis and then the transverse carpal ligament underneath it. Stay a bit ulnarly to prevent injury to the cutaneous branch of the median nerve but not too ulnar not to end up potentially harming the ulnar neurovasculature.

2. Make sure to carefully incise the transverse carpal ligament fully, from proximal to distal, so that all the pressure is released from the carpal tunnel. The tendons and the soft tissue might protrude slightly from the wound due to pressure.
   Be mindful of the median nerve which lies beneath the transverse ligament.

Releasing the Superficial Flexor Muscles

The goal is to release the antebrachial fascia surrounding the superficial volar muscles while simultaneously protecting the nearby neurovascular structures including the ulnar nerve and artery. Clearly necrotic tissue should be debrided since it can serve as a source of infection and further propagate tissue damage.

1. Identify the antebrachial fascia which is the continuation of the transverse and palmar carpal ligaments.

2. Use retractors to gain adequate visibility and carefully incise the antebrachial fascia using a scalpel.

3. Incise the fascia only under direct visualization.
   It is advised to use blunt dissection in places where you are not sure what lies under the structures to prevent iatrogenic injury to neurovascular structures.

4. Coagulate small vessels and identify superficial nerve structures and keep them intact whenever possible.

5. Continue opening the fascia moving proximally. When moving ulnarly keep in mind the ulnar nerve, artery, and vein near FCU.

6. When operating radially, notice the lateral antebrachial cutaneous nerve which runs subcutaneously. Beneath the brachioradialis is the superficial branch of the radial nerve, which surfaces in the distal forearm.

7. Open any clearly strained or bulging fasciae of muscle bellies as necessary and evacuate hematomas. Use the tips of your fingers to feel possible tight spots.

8. In the proximal forearm, the lacertus fibrosus (aponeurosis of distal biceps tendon which inserts into antebrachial fascia) should also be released, since the median nerve and volar muscles can be left entrapped under tight aponeurosis.

9. All encountered necrotic tissue should be debrided. Tissue that is not clearly unviable may be left alone in this first-look operation. Also, all hematomas should be evacuated to alleviate any additional pressure within the compartment. Hematomas can also serve as a potential site for infection to develop.

10. Finally, check that superficial flexor muscles are released. For example, palpate the area to ensure there are no tight spots or constrictions remaining, and if any are detected, release them.

Releasing the Deep Flexor Muscles

The goal is to release the deep flexor muscles thoroughly under good visualization while simultaneously protecting the neurovascular structures: the ulnar nerve and artery, the perforant branches of the ulnar artery, the median nerve, the anterior interosseous nerve (AIN), and artery. Most often insufficient release is seen in deep flexor muscles.

1. Identify FDS and FCU superficially. Also, the ulnar nerve is a good landmark for the differentiation of the superficial and deep muscles.

2. Retract FDS radially to expose the muscle belly of underlying deep muscles: FDP and FPL.
   Be aware of the median nerve coursing between FDS and FDP. Median nerve is often attached just underneath the FDS so keep this also in mind when retracting FDS out of the way, not to put too much tension to the nerve.

3. Release the relatively thin fascia of the FDP and FPL. Be aware of the perforant branches of ulnar artery running to the superficial muscles. Cauterize if necessary.
   Also keep in mind that the AIN and the anterior interosseous artery accompanying it course close by, between the FDP and FPL.

4. The release of the PQ is not shown here and is rarely necessary. Access can be gained distally between the ulnar neurovascular bundle and the FDS. Be aware of ulnar artery branches to the FDS, which might have to be ligated to get to PQ.

5. All necrotic tissue must be debrided. Tissue that is not clearly unviable may be left alone in this first-look operation.

6. Finally, check that deep flexor muscles are all completely released. For example, palpate the area to ensure there are no tight spots or constrictions remaining, and if any are detected, release them.

Releasing the Lateral Compartment (Mobile Wad)

The goal is to release the muscles of mobile wad while protecting the neurovascular structures: the superficial radial nerve and artery and the lateral antebrachial cutaneous nerve.

1. Identify brachioradialis in the radial aspect of the volar incision. Be aware of the superficial branch of the radial nerve and radial artery running under the brachioradialis.

2. Release the muscle belly from the entire length of the muscular area. Be also aware of the lateral antebrachial cutaneous nerve running in the subcutis on the brachioradialis.
   Distally, the superficial branch of the radial nerve runs subcutaneously. Therefore, avoid sliding open scissors without visual control to prevent injury.

3. Then move radially along the brachioradialis to release the muscle bellies of ECRB and ECRL.

4. All necrotic tissue must be debrided. Tissue that is not clearly unviable may be left alone in this first-look operation.

5. Finally, check that the mobile wad muscles are all completely released. For example, palpate the area to ensure there are no tight spots or constrictions remaining, and if any are detected, release them.

Releasing the Extensor Compartment

The goal is to release the muscles of extensor compartment while simultaneously protecting the neurovascular structures: the radial artery, the posterior interosseous nerve (PIN), and artery.

1. Pronating the forearm, if possible, gives better visualization and eases the release of the extensor muscles.

2. Palpate the lateral epicondyle where the muscles of the extensor compartment originate from and plan a straight dorsal incision starting from the lateral epicondyle and continuing distally towards the wrist. Leave enough intact skin between your volar and dorsal incision to prevent skin necrosis.
   Start with 10–12 cm incision since the muscle bellies of extensor muscles are short and situated mostly proximally.

3. Incise the skin with a scalpel and advance bluntly through the subcutaneous tissue to the fascia surface. Again, cauterize small bleeds.

4. A dorsal incision should reveal the ECRB and EDC muscle bellies. The fascia can be released along this muscle separation.

5. Move along the ECRB and EDC to release any other clearly strained or damaged muscle bellies.

6. Be aware of the PIN and the posterior interosseous artery running under the supinator deep to the extensor muscles.

7. All necrotic tissue must be debrided. Tissue that is not clearly unviable may be left alone in this first-look operation.

8. Finally, check that extensor compartment muscles are all completely released. For example, palpate the area to ensure there are no tight spots or constrictions remaining, and if any are detected, release them.

Verify Free Muscle Bellies, Check for Necrotic Tissue, and Ensure Hemostasis

The aim is to once more check that there are no tight spots left in any of the muscle compartments, no necrotic tissue is left behind, and that the surgical field is free from active bleeding.

1. Verify the superficial and deep flexor muscle compartments.

2. Verify the mobile wad.

3. Verify the extensor compartment.

4. No necrotic tissue should be left. Tissue that is not clearly unviable may be left alone in this first-look operation.

5. Cauterize all bleeding vessels. If necessary, suture larger vessels to achieve proper hemostasis.

6. Extend fasciotomy to the hand and/or upper arm if deemed necessary.

Closure

1. The skin should not be closed but rather irrigated and loosely bandaged. It is important not to wrap the dressing too tightly as it could exacerbate compartment pressures. Vacuum-assisted closure can be taken into consideration.

2. Apply a non-bulky, absorbing but moist surgical dressing that permits maximal postoperative hand and wrist mobility and allows examination of the distal limb.