ANTERIOR/VOLAR (HENRY’S) APPROACH TO THE FOREARM
- What are the indications for a volar approach to the forearm?
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- ORIF of fractures
- Bone grafting and fixation of non-unions
- Osteotomies
- Biopsy and treatment of bone tumours
- Anterior exposure of bicipital tuberosity
- Compartment syndrome of the forearm
- What is the internervous plane utilised by this approach?
The internervous planes are the same (radial nerve laterally and median nerve medi- ally) throughout the forearm, but the muscles encountered are different proximally and distally:
Proximally, I would retract brachioradialis (radial nerve) laterally and pronator teres (median nerve) medially
Distally, the brachioradialis (radial nerve) is taken laterally and flexor carpi radialis (medial nerve) medially
- How would you position the patient?
I would position the patient supine with an arm table attachment and an upper arm tourniquet. I wouldn’t exsanguinate the arm in order to keep the veins engorged. This assists with identification of the venae comitantes of the radial artery.
- Where would you base your incision?
The approach utilises an incision, which starts at the elbow flexor crease, medial to mobile wad, extending to the styloid process of the radius distally.
- Talk me through the superficial dissection.
I would extend the incision down through fat, taking care not to damage the cephalic vein, then identify the deep fascia. I would incise the deep fascia of the forearm in line with the skin incision. I would then identify the ulnar border of brachioradialis and develop the plane between it and flexor carpi radialis (FCR) distally and prona- tor teres proximally. Brachioradialis is the retracted laterally and pronator teres/ FCR is taken medially. It may be necessary to ligate/coagulate the leash of Henry (recurrent branches of the radial artery) to mobilise the brachioradialis laterally and the radial artery medially. The superficial radial nerve runs on the underside of bra- chioradialis and is retracted laterally with the muscle.
- Can you describe the deep dissection?
Usually only a portion of the approach is required and the deep dissection can be split into thirds: proximal, middle, distal. The arm should be supinated, pronated, supinated, respectively depending on the level of the fracture.
Proximal Third (forearm supinated)
The biceps insertion into the bicipital tuberosity of the radius is identified.
The radial artery is medial to the biceps tendon at this level, therefore the plane between biceps tendon and brachioradialis (laterally) is developed.
The proximal third of the radius is covered by the supinator, through which the posterior interosseus nerve (PIN) travels en route to the posterior compart- ment of the forearm.
Supination displaces the PIN from the surgical field and exposes the insertion of the supinator onto the anterior portion of the proximal radius. (Supination of the forearm will not have this effect when there is a radial shaft fracture, but can be achieved with bone reduction forceps.)
The supinator is incised in line with the radius and stripped subperiosteally in a radial direction, further displacing the PIN from the surgical field. Any retraction is performed carefully, as the PIN is at risk of a neurapraxia, which can take many months to recover. (NB: Never place retractors on the posterior surface of the radial neck, as these may compress the PIN, which comes into direct contact with this area in some patients.)
Middle Third (forearm pronated)
The middle third of the radial shaft is covered by pronator teres (PT) and flexor digitorum superficialis (FDS) muscles.
The arm is then pronated to expose the insertion of PT onto the lateral radial shaft.
The insertion is detached and the muscle is stripped off in an ulnar direction, which also detaches the origin of FDS.
Distal Third (forearm supinated)
The traditional Henry’s approach is radial to the radial artery, between brachio- radialis and the radial artery.
Two muscles arise from the anterior distal third of the radius: Pronator quadra- tus (PQ) and flexor pollicis longus (both innervated by the anterior interos- seus nerve).
The radial portion of PQ is incised and peeled off the distal radius in an ulnar direction with subperiosteal dissection.
My preferred approach in this region is the modified Henry’s approach to the distal radius through the bed of FCR. The sheath of FCR is incised and the tendon freed, before retracting this in an ulnar direction to protect the median nerve (radial artery is retracted radially) and going through the bed of FCR.
The sheath over FPL is incised and FPL is retracted ulnarly by sweeping this with a finger to reveal pronator quadratus (PQ).
To expose the distal radius, the radial portion of PQ is incised and peeled off the distal radius in an ulnar direction with subperiosteal dissection.
- What are the dangers of this approach?
Superficial radial nerve: This lies on the underside of brachioradialis and can be damaged with vigorous retraction.
Anterior/Volar (Henry’s) Approach to the Forearm 
Radial artery: This lies on the ulnar side of brachioradialis and can be damaged if not identified. Use of a tourniquet without exsanguination can allow for easier identification of the venae comitantes.
PIN: This travels through the body of the supinator and can be damaged when exposing the proximal third of the radial shaft. Retractors placed on the poste- rior surface of the radial neck may compress the PIN, which comes into direct contact with this area in some patients.
Cephalic vein: This commences in the anatomical snuffbox and runs from here, across the volar aspect of the forearm to the antecubital fossa. It is at risk in the superficial dissection of this approach, particularly in the proximal third.
- How may this approach be extended?
This approach can be extended proximally across the elbow into an anterolateral approach to the arm (67). Distally, the approach can be extended to allow for carpal tunnel decompression, for example, high-energy distal radius frac- tures with progressive median nerve symptoms. My preferred approach would be to perform a separate incision over the carpal tunnel to avoid crossing the path of the palmar cutaneous and recurrent motor branch of the median nerve.