Ulnar Nerve Decompression

What is Ulnar Nerve Decompression Surgery?

Ulnar nerve decompression surgery relieves compression of the ulnar nerve at the elbow — the most common cause of ulnar neuropathy (cubital tunnel syndrome). The procedure releases the nerve from the fibrous tunnel through which it passes at the inner side of the elbow, eliminating the compression causing pain, numbness, tingling, and weakness in the ring finger, little finger, and hand.

Two main surgical techniques are used: simple decompression (in situ release of the cubital tunnel ligament) and ulnar nerve transposition (moving the nerve from behind the medial epicondyle to a new position in front of it). One Brain and Spine's neurosurgeons will recommend the most appropriate approach based on the specific anatomy and cause of compression.

Simple Decompression vs Ulnar Nerve Transposition

• Simple decompression (in situ release) — the cubital tunnel retinaculum (Osborne's ligament) is divided, releasing the nerve in its normal position.  This is a shorter procedure, with a smaller incision and faster recovery.  Simple decompression is suitable for most cases when the nerve does not sublux (snap over the medial epicondyle) and bony anatomy is normal
• Anterior transposition — the ulnar nerve is moved from behind the medial epicondyle to a new position in front of it (subcutaneous, intramuscular, or submuscular transposition).  This is the preferred technique when the nerve subluxes over the epicondyle, when bony anatomy is abnormal (e.g. prior fracture), or when simple decompression has failed

Preoperative Preparation

Nerve conduction studies confirm ulnar nerve compression at the elbow, assess severity, and exclude other causes. MRI or ultrasound assesses bony anatomy and nerve entrapment. Blood thinners are ceased. The procedure is typically performed under general anaesthesia.

What Happens During Ulnar Nerve Decompression?

A longitudinal incision is made along the inner side of the elbow, centred over the medial epicondyle. The ulnar nerve is carefully identified and traced proximally into the upper arm and distally through the cubital tunnel into the forearm. The cubital tunnel retinaculum and any other fibrous bands compressing the nerve are completely divided, decompressing the nerve throughout its course.

For transposition, the nerve is further mobilised and moved to a new subcutaneous pocket in front of the medial epicondyle, held in its new position by a myofascial sling. The wound is closed in layers with dissolvable deep sutures and dissolvable skin sutures. The operation usually takes around 45 minutes, or longer if transposition is performed. It is usually performed as a day case.

Outcomes of Ulnar Nerve Surgery

More than 80% of patients achieve good-to-excellent outcomes with significant improvement in numbness, tingling, and pain following ulnar nerve decompression or transposition. Motor recovery is more variable — grip strength and fine finger function improve substantially in most patients, but recovery is slower and may be incomplete in those with longstanding or severe compression.

Risks and Complications

• Wound infection — approximately 1%
• Haematoma — collection of blood at the wound site; rarely requires drainage
• Nerve injury — damage to the ulnar nerve or medial cutaneous nerve of the forearm; persistent or worsening numbness or weakness; rare
• Complex regional pain syndrome — rare (approximately 0.3%)
• Limited elbow extension — transient stiffness; responds to physiotherapy
• Medial elbow instability — from excessive medial epicondyle dissection; avoided with careful technique
• Incomplete relief — approximately 10–20% of patients have minimal improvement; depends on pre-existing nerve damage severity