Ulnar Nerve Release
- Author: Cristian Gragnaniello, MD; Chief Editor: Thomas M DeBerardino, MD more...
Ulnar nerve release is indicated for cubital tunnel syndrome with positive clinical and instrumental signs (nerve conduction studies and electromyography [EMG]) of compression at the elbow.
In 1957, Osborne described simple decompression of the ulnar nerve achieved by cutting the ligament subsequently named after him (the Osborne fascia or band). This ligament is part of the fibrous arcade, a fascia running between the two heads of the flexor carpi ulnaris (FCU). Osborne divided this fibrous band connecting the medial epicondyle and olecranon and reported results favorable to those of the anterior transposition procedures, which at that time represented the standard of surgical care for compressive ulnar neuropathies at the elbow.
In his report, Osborne observed that the ulnar neuritis was a result of direct compression of the nerve within the tunnel and that the flexion of the elbow exacerbated this condition.
The compression causes progressive disruption of the vascular supply to the nerve. In a normal elbow, the nerve undergoes tensile forces that increase the nerve strain; when the elbow is flexed, the nerve is pushed against its bed, and upon extension, the nerve diverges away from the elbow.
The ulnar nerve at the elbow could be compressed at different sites, as follows:
Proximal to the cubital tunnel at the level of the medial epicondyle - The arcade of Struthers is a canal made up by the intermuscular septum, the internal brachial ligament, and the triceps; at this site, between the middle and distal thirds of the humerus, the ulnar nerve travels from the anterior to the posterior compartment of the arm
Distal to the cubital tunnel - The compression might be caused by the arcuate ligament of Osborn that runs between the two heads of origin of the FCU and therefore between the medial epicondyle of the humerus and the medial aspect of the olecranon
Ulnar nerve compression at the elbow is the second most common compression neuropathy in the upper limbs (after median nerve compression in the carpal tunnel), with an incidence of 25 per 100,000 population per year. The condition is more common in men than in women, possibly as a consequence of the smaller coronoid process of the ulna and more abundant subcutaneous fat tissue in women.
Nontraumatic ulnar nerve compressive neuropathy is usually associated with arthritis, and there are no other known causes.
Individuals with ulnar nerve neuropathy present with sensorimotor deficits in the territory of the ulnar nerve. Typically, numbness and tingling of the fingers innervated by the ulnar nerve occur first, followed by weakness. Pain may occur behind the elbow. Symptoms may be exacerbated by elbow flexion; this is especially apparent at night.
In severe cases, atrophy of the intrinsic muscles of the hand at the hypothenar eminence may develop, from mild to severe, including the Froment sign, in which the abductor pollicis is weak, so the patient tends to flex the proximal interphalangeal joint of the thumb and extend the distal phalanx while grasping between the thumb and index finger to overcome the weakness of the abduction.
The patient can also present with a positive Wartenberg sign, in which the little finger is abducted owing to interosseous weakness. The Tinel sign may be positive at the elbow.
In severe cases, the benediction hand sign may also be seen, in which the last two fingers are less extended than the others when the patient tries to extend them all.
EMG is very useful in detecting peripheral neuropathies, and a velocity of less than 50 m/s across the elbow is highly suggestive of a compression at that level.
Magnetic resonance imaging (MRI) is useful for ruling out compressions of the nerve by tumors and cystic pathologies of the soft tissue and joints.
Amyotrophic lateral sclerosis, Guillain-Barré syndrome, Charcot-Marie-Tooth disease, and hereditary neuropathy with liability to pressure palsies (HNPP) can all present with symptoms of ulnar nerve weakness and must be ruled out, as well as cervical nerves palsies, thoracic outlet syndrome, and compression of the nerve at the canal of Guyon.
Ulnar nerve release is indicated for cubital tunnel syndrome with positive clinical and instrumental signs (nerve conduction studies and EMG) of compression at the elbow.
Contraindications to ulnar nerve release include the following:
Valgus deformity of the elbow
Elbow instability or deformity
Relative contraindications include recurrent neuropathies.
A delayed diagnosis increases the risk of chronic neuritis and pain due to repeated injuries to the nerve, leading to intraneural scar formation. Surgical treatment in this case is less effective in the long term. Negative prognostic factors include severe, long-lasting neuropathy accompanied by diminished conduction velocity of the nerve.
A randomized controlled trial of 70 patients with mild or moderate but not necessarily electrophysiologically proven cubital tunnel syndrome sought to assess the efficacy of conservative therapy at 6 months. The study subjects were divided into the following three groups:
Nocturnal elbow splinting for 3 months plus written information
Nerve gliding exercises plus written information
Written information only
The attrition rates among the three groups were high and equal, with 13 patients unavailable for follow-up and six others requesting surgical decompression. The authors found that written information improved occupational activities and pain, but the addition of splinting or exercises did not confer any further benefit.
Medial epicondylectomy versus anterior ulnar nerve transposition for ulnar neuropathy at the elbow was examined in a randomized controlled trial of 47 operations. Neurologic assessment of the hand and elbow at a minimum of 1 year showed no clinical difference between the two groups, though mild hand pain was more common after transposition. Patient satisfaction seemed better after medial epicondylectomy.
A handful of randomized controlled trials have compared clinical and nerve conduction outcomes of simple decompression versus anterior ulnar nerve transposition in patients with electrophysiologically proven ulnar neuropathy at the elbow.[4, 5, 6, 7]
Bartels et al compared simple decompression with anterior subcutaneous transposition in 152 patients. At 1-year follow-up, equivalent good or excellent clinical improvement was noted in both groups (65% decompression, 70% subcutaneous), though the transposition group had significantly higher rates of complications (10% decompression, 31% subcutaneous). An economic analysis of this trial revealed simple decompression cost significantly less than transposition, mainly owing to significantly shorter operative time and sick leave.
Nabhan et al also examined simple decompression versus anterior subcutaneous transposition in a randomized controlled trial of 66 patients with 9-month follow-up. The two procedures achieved similar improvements in clinical and nerve conduction velocities across the elbow.
Biggs and Curtis and Gervasio et al compared simple decompression with anterior submuscular transposition. At 1-year followup, Biggs and Curtis reported a nonsignificant difference in neurologic improvement between groups in their cohort of 44 patients (61% decompression, 67% submuscular), with a trend for deep wound infection in the transposition group (0% decompression, 14% submuscular).
At 6-month follow-up, Gervasio et al reported a nonsignificant difference in good or excellent clinical and electrophysiologic outcomes between groups in their cohort of 70 patients (80% decompression, 83% submuscular), with no major complications observed.
The data from these studies were cumulatively evaluated in a 2011 Cochrane review. The meta-analysis found that both simple decompression and anterior transposition procedures improve symptoms and nerve function and that no significant difference in postoperative clinical or electrophysiologic outcomes existed; however, transposition resulted in higher rates of deep and superficial wound infection.
In summary, conservative therapy would be appropriate for patients with mild or moderate symptoms of ulnar neuropathy at the elbow. In more severe cases requiring surgical intervention, clinical improvement may be expected in approximately 70% of cases. No one surgical technique has been shown to be superior to another.
In view of the evidence from these randomized controlled trials, there has been increasing advocacy for simple decompression as the operation of choice given its shorter operating time, potential economic benefits, and association with fewer complications.
In a 2014 study by Martin et al, 145 patients underwent retractor-endoscopic carpal tunnel release (n = 47), endoscopic in-situ decompression of the ulnar nerve (n = 55), or endoscopic anterior transposition of the ulnar nerve (n = 52) between 2000 and 2010; nine patients underwent bilateral procedures. Both objective results (via independent examination at 24 months) and subjective results (via questionnaire) were recorded, as follows:
Endoscopic carpal tunnel release - 59.6% had excellent objective results, 21.2% good results, 12.8% fair results, and 6.4% poor results; 85% had subjective improvement
Endoscopic in-situ decompression - 56.4% had excellent objective results, 32.7% good results, 9.1% fair results, and 1.8% poor results; 72.7% had subjective improvement
Endoscopic anterior transposition of the ulnar nerve - 48.1% had excellent objective results, 26.9% good results, 23.1% fair results, and 1.9% poor results; 65.4% had subjective improvement
The investigators found that the retractor-endoscopic approach yielded good long-term results after carpal tunnel release, in-situ decompression, and anterior subcutaneous transposition of the ulnar nerve, with outcomes showing some correlation with the duration of preoperative symptoms.
Palmer BA, Hughes TB. Cubital tunnel syndrome. J Hand Surg Am. 2010 Jan. 35(1):153-63. [Medline].
Svernlov B, Larsson M, Rehn K, Adolfsson L. Conservative treatment of the cubital tunnel syndrome. J Hand Surg Eur Vol. 2009 Apr. 34(2):201-7. [Medline].
Geutjens GG, Langstaff RJ, Smith NJ, Jefferson D, Howell CJ, Barton NJ. Medial epicondylectomy or ulnar-nerve transposition for ulnar neuropathy at the elbow?. J Bone Joint Surg Br. 1996 Sep. 78(5):777-9. [Medline].
Bartels RH, Verhagen WI, van der Wilt GJ, Meulstee J, van Rossum LG, Grotenhuis JA. Prospective randomized controlled study comparing simple decompression versus anterior subcutaneous transposition for idiopathic neuropathy of the ulnar nerve at the elbow: Part 1. Neurosurgery. 2005 Mar. 56(3):522-30; discussion 522-30. [Medline].
Biggs M, Curtis JA. Randomized, prospective study comparing ulnar neurolysis in situ with submuscular transposition. Neurosurgery. 2006 Feb. 58(2):296-304; discussion 296-304. [Medline].
Gervasio O, Gambardella G, Zaccone C, Branca D. Simple decompression versus anterior submuscular transposition of the ulnar nerve in severe cubital tunnel syndrome: a prospective randomized study. Neurosurgery. 2005. 56(1):108-17; discussion 117. [Medline].
Nabhan A, Ahlhelm F, Kelm J, Reith W, Schwerdtfeger K, Steudel WI. Simple decompression or subcutaneous anterior transposition of the ulnar nerve for cubital tunnel syndrome. J Hand Surg Br. 2005 Oct. 30(5):521-4. [Medline].
Bartels RH, Termeer EH, van der Wilt GJ, van Rossum LG, Meulstee J, Verhagen WI. Simple decompression or anterior subcutaneous transposition for ulnar neuropathy at the elbow: a cost-minimization analysis--Part 2. Neurosurgery. 2005 Mar. 56(3):531-6; discussion 531-6. [Medline].
Caliandro P, La Torre G, Padua R, Giannini F, Padua L. Treatment for ulnar neuropathy at the elbow. Cochrane Database Syst Rev. 2011. (2):CD006839. [Medline].
Martin KD, Dützmann S, Sobottka SB, Rambow S, Mellerowicz HA, Pinzer T, et al. Retractor-endoscopic nerve decompression in carpal and cubital tunnel syndromes: outcomes in a small series. World Neurosurg. 2014 Jul-Aug. 82(1-2):e361-70. [Medline].
Mandelli C, Baiguini M. Ulnar nerve entrapment neuropathy at the elbow: decisional algorithm and surgical considerations. Neurocirugia (Astur). 2009 Feb. 20(1):31-8. [Medline].
Mitsionis GI, Manoudis GN, Paschos NK, Korompilias AV, Beris AE. Comparative study of surgical treatment of ulnar nerve compression at the elbow. J Shoulder Elbow Surg. 2010 Jun. 19(4):513-9. [Medline].
Abuelem T, Ehni BL. Minimalist cubital tunnel treatment. Neurosurgery. 2009 Oct. 65(4 Suppl):A145-9. [Medline].
Eversman W. Complications of compression of entrapment neuropathies. B. JA. Complications in Hand Surgery. Philadelphia: WB Saunders; 1989. 99-105.