Dorsal Approach to Radius
The Dorsal approach to radius also called Thompson approach, provides good access to the entire dorsal aspect of the radial shaft.
- The Dorsal approach to radius is used for:
- ORIF of radial shaft fractures using extensor side of bone.
- Treatment of delayed union or nonunion of fractures of the radius .
- Access to the posterior interosseous nerve as it passes through the arcade of Frohse for:
- nerve paralysis.
- resistant tennis elbow.
- Radial osteotomy.
- Osteomyelitis and bone tumor resection/biopsy.
- Place the patient in the Supine position:
- If the arm is abducted to the side on an arm board, the forearm should be pronated.
- If the arm is adducted across the chest, the forearm should be supinated,
- If the ulna must be approached as well as the radius, this position will allow easier access to the ulna through a separate incision.
- Landmarks:
- Proximal:
- Lateral epicondyle of the humerus.
- Distal:
- Dorsoradial tubercle (Lister’s tubercle).
- Proximal:
- Incision:
- Starting point is anterior and distal to the lateral epicondyle of the humerus,
- straight or gently curved incision along the dorsolateral aspect of the forearm,
- be aware of superficial radial nerve and cephalic vein distally.
- end incision just distal and ulnar to Lister’s tubercle.
- The Internervous plane for the Dorsal approach to radius (Thompson approach) is:
- Proximally between:
- Extensor carpi radialis brevis muscle (ECRB): innervated by the radial nerve.
- Extensor digitorum communis muscle (EDC): innervated by the posterior interosseous nerve.
- Distally between:
- Extensor carpi radialis brevis muscle (ECRB): innervated by the radial nerve.
- extensor pollicis longus muscle (EPL): innervated by the posterior interosseous nerve.
- Proximally between:
- Proximal third:
- Incise fascia in line with skin incision using interval between extensor carpi radialis brevis muscle (ECRB) and the extensor digitorum communis muscle (EDC) to reveal supinator muscle.
- Middle third:
- Identify the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) emerging between extensor carpi radialis brevis muscle (ECRB) and the extensor digitorum communis muscle (EDC).
- Distal third:
- Undermine the abductor pollicis longus (APL) and extensor pollicis brevis tendons medially to identify plane between extensor pollicis longus and extensor carpi radialis brevis muscle (ECRB).
- Proximal third:
- Identify the insertion of supinator by turning arm into full supination,
- supination moves the posterior interosseous nerve away from area of deep dissection.
- incise insertion of supinator along radius and subperiosteally strip supinator off bone to expose proximal third of radius.
- for more proximal exposures, two deep approaches exist to protect posterior interosseous nerve:
- dissecting proximal to distal:
- detach origin of extensor carpi radialis brevis muscle (ECRB) and
- extensor carpi radialis longus muscle (ECRL) from lateral epicondyle and identify and dissect posterior interosseous nerve as it enters supinator muscle.
- dissecting distal to proximal:
- identify nerve as it exits supinator and dissect it proximally out of supinator substance.
- dissecting proximal to distal:
- Middle third:
- Make incision along superior and inferior borders of abductor pollicis longus (APL) and extensor pollicis brevis (EPB).
- retract them off bone to expose middle third of radius.
- Distal third:
- separating the extensor carpi radialis brevis muscle (ECRB)and extensor pollicis longus (EPL) will directly lead to the lateral border of the radius.
- part of the interosseous membrane may have to be removed to approach the radius.
- The dorsal approach to radius (Thompson approach) can be extended to the dorsal side of the wrist ( Dorsal Approach to the Wrist ).
- Dorsal approach to radius (Thompson approach) can be extended proximally to expose the lateral epicondyle of the humerus ( Lateral Approach to Distal Humerus ).
The structures at risk during dorsal approach to radius (Thompson approach) include:
- Posterior interosseous nerve (branch of radial nerve):
- Injury usually occurs from retraction.
- In 25% of patients the nerve actually touches the dorsal aspect of the radius.
- Plates placed high on the dorsal surface may trap the nerve.
- Posterior interosseous nerve must be identified within the supinator muscle.
- Posterior interosseous artery:
- Accompanies the Posterior interosseous nerve along the interosseous membrane in the proximal 1/3 of radius.
- Surgical Exposures in Orthopaedics book - 4th Edition
- Campbel's Operative Orthopaedics book 12th