What is the modified Henry approach in surgery?

The Modified Henry Approach in Surgery

The modified Henry approach is a surgical technique for exposing the radius shaft that provides safe access to the entire lateral and anterior surfaces of the radius while minimizing the risk of injury to the deep branch of the radial nerve. 1

Anatomical Basis and Indications

• The modified Henry approach is a variation of the original Henry approach, which was first described in 1945 and is considered the "workhorse" for exposing the volar radius 2
• Unlike the Thompson posterolateral approach (which is safe only for middle and distal thirds of the radius), the Henry approach can be used for fractures in any part of the radial shaft 1
• This approach is particularly valuable for treating distal radius fractures and midshaft diaphyseal radius fractures 3, 2

Surgical Technique

The modified Henry approach consists of three phases:

Phase 1: Skin Incision

• An incision is made along the line connecting the biceps brachii tendon and the styloid process of radius 1
• Care must be taken to avoid damaging the lateral cutaneous nerve of the forearm 1

Phase 2: Fascial Incision and Neurovascular Protection

• The fascia is incised and the brachioradialis muscle is identified by the typical transition from muscle belly to tendon 1
• On the lateral side, the brachioradialis borders a space containing the radial artery, veins, and superficial branch of the radial nerve 1
• The superficial branch of the radial nerve is retracted laterally with the brachioradialis, while the radial artery is retracted medially 1
• Surgeons must be particularly careful in the middle portion of the radius (40-80% of radius length from the styloid process) where the radial artery crosses the surgical approach 4

Phase 3: Deep Exposure

• The pronator teres insertion is identified by its typical tendon in the middle of the lateral surface of the radial shaft 1
• For proximal radius exposure, dissection begins at the pronator teres insertion and proceeds proximally along its lateral border 1
• The supinator muscle is carefully released and retracted posterolaterally, always working from distal to proximal 1
• Supination of the proximal fragment (using a K-wire) helps move the supinator canal posteriorly, reducing risk to the deep branch of the radial nerve 1

Modifications and Variations

• Pronator teres-sparing modification: A variation that preserves the pronator teres muscle during exposure, offering theoretical advantages over the original Henry approach for midshaft radius fractures 2
• Trans-flexor carpi radialis (FCR) modification: An alternative approach for distal radius fractures, though it may cause more tenderness in the FCR tendon area compared to the conventional Henry approach 3
• Pronator quadratus repair technique: After distal radius fixation, the pronator quadratus muscle can be repaired using an outward-return running suture with a 2.0 single-strand thread to restore muscle integrity and isolate the flexor system from osteosynthesis material 5

Advantages and Considerations

• The modified Henry approach provides safe exposure of the entire lateral and anterior surfaces of the radius 1
• It allows access to the proximal radius with less risk to the deep branch of the radial nerve compared to the Thompson approach 1
• When properly executed, this approach enables repair of the pronator quadratus muscle after osteosynthesis of distal radius fractures 5
• For distal radius fractures, the conventional Henry approach may cause less tenderness in the FCR tendon area compared to the trans-FCR modification 3

Potential Complications

• Injury to the deep branch of the radial nerve is a feared complication, especially when exposing the proximal third of the radius 1
• Damage to the radial artery is possible, particularly in the middle portion of the radius where the artery crosses the surgical approach 4
• FCR tendon area tenderness may occur, especially with the trans-FCR modification 3

The modified Henry approach represents an important technique in orthopedic surgery that, when properly executed, provides safe and effective access to the radius for fracture fixation while minimizing neurovascular complications.