Summary Cubital Tunnel Syndrome is a compressive neuropathy of the ulnar nerve caused by anatomic compression in the medial elbow. Diagnosis is made clinically with presence of sensory changes to the ring and little finger, intrinsic muscle weakness and a positive tinel's sign over the cubital tunnel. Treatment may be nonoperative modalities such as bracing or surgical decompression depending on the severity and duration of symptoms, and success of nonoperative treatment. Epidemiology Incidence common ~30 per 100,000 person annually login to view 1 more bullet Demographics males > females females more likely to present at earlier age incidence increases with age in both men and women Etiology Pathophysiology Cubital tunnel syndrome results from compression and traction on the ulnar nerve Sites of entrapment most common login to view 3 more bullets less common sites of compression include login to view 6 more bullets external sources of compression login to view 5 more bullets Associated conditions cubitus varus or valgus deformities medial epicondylitis burns elbow contracture release Anatomy Ulnar nerve arises from the medial cord of the brachial plexus (C8-T1) lies posteromedial to brachial artery in anterior compartment of upper arm pierces IM septum at arcade of Struthers 8 cm proximal to the medial epicondyle runs behind medial epicondyle within the cubital tunnel enters forearm between 2 heads (humeral and ulnar heads) of FCU runs between FCU and FDP passes superficial to the transverse carpal ligament at the wrist Cubital tunnel roof formed by FCU fascia and Osborne's ligament (travels from the medial epicondyle to the olecranon) floor formed by posterior oblique and transverse bands of MCL and elbow joint capsule walls formed by medial epicondyle and olecranon Classification McGowan and Dellon Type 1 Subjective sensory symptoms without objective loss of two-point sensibility or muscular atrophy Type 2A Sensory symptoms + weakness on pinch and grip without atrophy Type 2B Sensory symptoms + atrophy and intrinsic muscle strength ≤ 3 Type 3 Profound muscular atrophy and sensory disturbance Presentation Symptoms paresthesias of small finger, ulnar half of ring finger, and ulnar dorsal hand exacerbating activities include login to view 2 more bullets night symptoms caused by sleeping with arm in flexion Physical exam inspection and palpation interosseous and first web space atrophy ring and small finger clawing observe ulnar nerve subluxation over the medial epicondyle as the elbow moves through a flexion-extension arc sensory decreased sensation in ulnar 1-1/2 digits motor loss of the ulnar nerve results in paralysis of intrinsic muscles (adductor pollicis, deep head FPB, interossei, and lumbricals 3 and 4) which leads to login to view 15 more bullets extrinsic weakness Pollock's sign login to view 1 more bullet provocative tests Tinel sign positive over cubital tunnel elbow flexion test login to view 1 more bullet direct cubital tunnel compression exacerbates symptoms Studies EMG / NCS helpful in establishing diagnosis and prognosis threshold for diagnosis conduction velocity <50 m/sec across elbow low amplitudes of sensory nerve action potentials and compound muscle action potentials Differential Ulnar Tunnel Syndrome key findings that differentiate cubital tunnel syndrome from ulnar tunnel syndrome found with cubital tunnel syndrome login to view 5 more bullets C8 radiculopathy key finding that differentiate cubital tunnel syndrome from a C8 radiculpathy cubital tunnel syndrome login to view 1 more bullet C8 radiculopathy login to view 2 more bullets Treatment Nonoperative NSAIDs, activity modification, and nighttime elbow extension splinting indications login to view 1 more bullet outcomes login to view 1 more bullet Operative in situ ulnar nerve decompression without transposition indications login to view 2 more bullets outcomes login to view 3 more bullets ulnar nerve decompression and anterior transposition indications login to view 3 more bullets outcomes login to view 4 more bullets medial epicondylectomy indications login to view 2 more bullets outcomes login to view 1 more bullet Techniques NSAIDs, activity modification, and nighttime elbow extension splinting technique night bracing in 45° extension with forearm in neutral rotation In situ ulnar nerve decompression releasing the fascial structures superficial to the ulnar nerve along the medial aspect of the elbow 4-cm incision midway between the olecranon and medial epicondyle distally release Osborne ligament and the superficial and deep fascia of FCU proximally release the fascia between the medial triceps and medial intermuscular septum avoid circumferential dissection of the nerve to minimize devascularization and to avoid creating hypermobility of the nerve endoscopically-assisted cubital tunnel release is an option favorable early results but lacks long-term data Decompression and transposition (submuscular, intramuscular, or subcutaneous) decompress the nerve and circumferentially dissect the nerve to allow for transposition excise the medial intermuscular septum anteriorly transpose the nerve secured with subcutaneous tissue, placed anterior to a fascial sling, or placed within or beneath the flexor pronator mass Medial Epicondylectomy decompress the nerve and then perform an oblique osteotomy of the medial epicondyle preserve the insertion of the MCL + repair the periosteum Complications Recurrence secondary to inadequate decompression, perineural scarring, or tethering at the intermuscular septum or FCU fascia higher rate of recurrence than after carpal tunnel release Neuroma formation iatrogenic injury to a branch of the medial antebrachial cutaneous nerve may cause persistent posteromedial elbow pain crosses field 3cm distal to medial epicondyle