- ORIF of radial fractures and treatment of delayed union or nonunion of fractures of the radius.
- Radial osteotomy.
- Access to the posterior interosseous nerve; nerve decompression as it passes through the arcade of Frohse.
- Treatment of chronic osteomyelitis of the radius.
- Biopsy and treatment of bone tumors.
- Provides good access to the entire dorsal aspect, the extensor side, of the radius; this is the tensile side of the bone, where plates should be placed if possible.
- This approach allows isolation and retraction of the posterior interosseous nerve before exposing the highest parts of the radial shaft, keeping the nerve under direct observation.
Position of patient
- The patient is placed supine on the operating table, with the arm on an arm board. Pronate the patient's arm to expose the extensor compartment of the forearm.
- Place the patient's arm across the chest. Supinate the forearm to expose its extensor compartment. This position is preferred in cases in which the surgeon needs to access both bones of the forearm, as it allows easier access to the ulna through a separate incision.
Landmarks and incision
- The lateral epicondyle of the humerus, just lateral to the olecranon process on the distal humerus is identified.
- Lister's tubercle feels like a small, longitudinal bony prominence or nodule; it lies about a third of the way across the dorsum of the wrist.
- Make gently curved incision, extending from a point anterior to the lateral epicondyle to a point just distal to the ulnar side of Lister's tubercle at the wrist.
- In case of fracture, the incision is centered over the fracture site; not all the length of the incision is needed.
- Proximally, between the extensor carpi radialis brevis muscle (radial nerve) and the extensor digitorum communis muscle (posterior interosseous nerve).
- Distally, between the extensor carpi radialis brevis muscle (radial nerve) and the extensor pollicis longus muscle (the posterior interosseous nerve).
- The deep fascia is incised in line with the skin incision and the space between the extensor carpi radialis brevis and the extensor digitorum communis is identified.
- Distally, the gap is more obvious, where the abductor pollicis longus and the extensor pollicis brevis emerge from between the two muscles.
- Proximally, the extensor carpi radialis brevis and the extensor digitorum communis share a common aponeurosis. Separating the two muscles reveals the upper third of the shaft of the radius, which is covered by the supinator muscle.
- Distal to the abductor pollicis longus and the extensor pollicis brevis, the intermuscular plane between the extensor carpi radialis brevis and the extensor pollicis longus is identified. Separating the two muscles exposes the lateral aspect of the shaft of the radius.
- The posterior interosseous nerve emerges between the superficial and deep heads of the supinator muscle, about 1 cm proximal to the distal edge of the muscle.
- Two methods exist for identifying and preserving the nerve as it traverses the muscle:
1. Proximal to distal, detach the origin of the extensor carpi radialis brevis and part of the origin of the extensor carpi radialis longus from the lateral epicondyle; retract these two muscles laterally. Identify the posterior interosseous nerve proximal to the proximal end of the supinator muscle by palpating the nerve. Dissect the nerve out through the substance of the supinator, in a proximal to distal direction.
2. Distal to proximal, the nerve is identified as it emerges from the supinator about 1 cm proximal to the distal end of the muscle. Follow the nerve proximally through the substance of the muscle, taking care to preserve all muscular branches.
- Fully supinate the arm to bring the anterior surface of the radius into view. Detach the insertion of the supinator muscle from the anterior aspect of the radius and strip it off the bone subperiosteally to expose the proximal third of the shaft of the radius.
- The abductor pollicis longus and the extensor pollicis brevis cross the dorsal aspect of the radius before heading distally and radially across the middle third of the radius.
- Make an incision along their superior and inferior borders to separate them from the underlying radius.
- Retract the two muscles either distally or proximally, depending on the exposure that is required.
- Separating the extensor carpi radialis brevis from the extensor pollicis longus led directly onto the lateral border of the radius.
Posterior interosseous nerve
- Identifying and preserving the nerve in the supinator muscle is the only means of ensuring that it will not be trapped beneath any plate that is applied for a radial fracture, as the nerve touches the dorsal aspect of the radius opposite the bicipital tuberosity.
- Protecting the nerve with the supinator muscle substance. The safest procedure is to dissect the nerve out fully before stripping the supinator from the bone, as the nerve actually touches the periosteum in one of four patients.
How to enlarge the approach
- Detach the origin of the extensor carpi radialis brevis from the common extensor origin on the lateral epicondyle to widen the plane between the extensor carpi radialis brevis and the extensor digitorum communis muscles.
- The approach can be extended to the dorsal side of the wrist, as well proximally, to expose the lateral epicondyle of the humerus.
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