Mateusz Gładysz FESSH prep

FESSH prep Compressive neuropathies Five compression sites, cubital tunnel pressure and area with flexion, anconeus epitrochlearis prevalence, complications of transposition versus in situ decompression, medial antebrachial cutaneous nerve branches

Cubital tunnel: surgical anatomy and the decompression-versus-transposition evidence

Last reviewed v1.0

FESSH-051Compressive neuropathies●●○ intermediate

Regarding the surgical anatomy of the cubital tunnel and the choice between in situ decompression and anterior transposition:

  1. 1.Passing from proximal to distal, the ulnar nerve may be compressed at the arcade of Struthers, the medial intermuscular septum, the retrocondylar groove behind the medial epicondyle, the cubital tunnel retinaculum (Osborne's ligament), the humeroulnar arcade between the two heads of flexor carpi ulnaris and, distally, the deep flexor-pronator aponeurosis.

  2. 2.Flexing the elbow to about 135° reduces the cross-sectional area of the cubital tunnel by roughly 30–40 %, and at 130° of flexion the intraneural pressure is about 45 % higher than the surrounding extraneural pressure.

  3. 3.Pooled prevalence data show that an anconeus epitrochlearis muscle is more common in patients with cubital tunnel syndrome than in healthy elbows.

  4. 4.Randomised evidence shows fewer wound complications after anterior transposition than after simple in situ decompression.

  5. 5.Branches of the medial antebrachial cutaneous nerve cross the line of a standard cubital tunnel incision distal to the medial epicondyle in every patient (100 per cent of 97), on average 3.1 cm distal to it.

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Question ID
FESSH-051
First published
Last reviewed
Version
v1.0
Answer key and explanations — open after answering

  1. 1. Passing from proximal to distal, the ulnar nerve may be compressed at the arcade of Struthers, the medial intermuscular septum, the retrocondylar groove behind the medial epicondyle, the cubital tunnel retinaculum (Osborne's ligament), the humeroulnar arcade between the two heads of flexor carpi ulnaris and, distally, the deep flexor-pronator aponeurosis.

    True

    The German guideline review defines the cubital tunnel as three parts — the retrocondylar groove partly covered by the cubital tunnel retinaculum (Osborne's ligament), the humeroulnar arcade and the deep flexor-pronator aponeurosis — and notes that decompression must extend at least 5–6 cm distal to the epicondyle. Proximally, the arcade of Struthers is a fibrous canal about 5.7 cm long whose openings lie 3.9 and 9.6 cm above the epicondyle; its tightest point, at the intermuscular septum, is the clinically relevant proximal site of compression.

    • Assmus H, Antoniadis G, Bischoff C, Hoffmann R, Martini AK, Preissler P, et al.. Cubital tunnel syndrome - a review and management guidelines. Cent Eur Neurosurg. 2011;72(2):90-8. PMID 21547883
    • von Schroeder HP, Scheker LR. Redefining the "Arcade of Struthers". J Hand Surg Am. 2003;28(6):1018-21. PMID 14642520

  2. 2. Flexing the elbow to about 135° reduces the cross-sectional area of the cubital tunnel by roughly 30–40 %, and at 130° of flexion the intraneural pressure is about 45 % higher than the surrounding extraneural pressure.

    True

    Gelberman measured 20 cadaver elbows with MRI and interstitial pressure catheters: from full extension to 135° of flexion the cross-sectional area of the cubital tunnel fell by 30, 39 and 41 % at the epicondyle, beneath the aponeurosis and beneath flexor carpi ulnaris, and the area of the nerve by 33, 50 and 34 %. Intraneural pressure was significantly higher than extraneural pressure at 90°, 100°, 110° and 130° of flexion and 45 % higher at 130°, and the tunnel narrowed most beneath the aponeurotic roof at 135°; in this model, release of the aponeurotic roof alone did not measurably lower intraneural pressure.

    • Gelberman RH, Yamaguchi K, Hollstien SB, Winn SS, Heidenreich FP Jr, Bindra RR, et al.. Changes in interstitial pressure and cross-sectional area of the cubital tunnel and of the ulnar nerve with flexion of the elbow. An experimental study in human cadavera. J Bone Joint Surg Am. 1998;80(4):492-501. PMID 9563378

  3. 3. Pooled prevalence data show that an anconeus epitrochlearis muscle is more common in patients with cubital tunnel syndrome than in healthy elbows.

    False

    In a meta-analysis of 40 studies the pooled prevalence of anconeus epitrochlearis was 14.2 % in healthy subjects but only 4.5 % in cubital tunnel syndrome patients, with no sex or side difference and a higher frequency in Europeans (18.2 %); the authors suggest that the muscle may protect the nerve, although when present in a symptomatic elbow it tends to be hypertrophied. Classic teaching, from O'Driscoll's type II retinaculum (the band replaced by the muscle in 3 of 27 elbows), treated it as a compressing structure to be released.

    • Suwannakhan A, Chaiyamoon A, Yammine K, Yurasakpong L, Janta S, Limpanuparb T, et al.. The prevalence of anconeus epitrochlearis muscle and Osborne's ligament in cubital tunnel syndrome patients and healthy individuals: An anatomical study with meta-analysis. Surgeon. 2021;19(6):e402-e411. PMID 33551294
    • O'Driscoll SW, Horii E, Carmichael SW, Morrey BF. The cubital tunnel and ulnar neuropathy. J Bone Joint Surg Br. 1991;73(4):613-7. PMID 2071645

  4. 4. Randomised evidence shows fewer wound complications after anterior transposition than after simple in situ decompression.

    False

    In Bartels' randomised trial of 152 patients, excellent or good results were equally frequent after simple decompression (49 of 75) and anterior subcutaneous transposition (54 of 77), but complications were far more common after transposition (31.1 % versus 9.6 %; risk ratio 0.32), and the authors advised simple decompression even when the nerve subluxes. The 2016 Cochrane review (nine trials, 587 participants) likewise found no difference in clinical or neurophysiological improvement and more wound infections after transposition (risk ratio 0.32 in favour of decompression).

    • Bartels RHMA, Verhagen WIM, van der Wilt GJ, Meulstee J, van Rossum LGM, 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;56(3):522-530. PMID 15730578
    • Caliandro P, La Torre G, Padua R, Giannini F, Padua L. Treatment for ulnar neuropathy at the elbow. Cochrane Database Syst Rev. 2016;11(11):CD006839. PMID 27845501

  5. 5. Branches of the medial antebrachial cutaneous nerve cross the line of a standard cubital tunnel incision distal to the medial epicondyle in every patient (100 per cent of 97), on average 3.1 cm distal to it.

    True

    In Lowe's prospective study of 97 primary cubital tunnel operations, branches of the medial antebrachial cutaneous nerve crossed the approach distal to the epicondyle in 100 % of cases at a mean of 3.1 cm, and at or proximal to it in 61 % at a mean of 1.8 cm. Injury produces a painful neuroma or numbness that is easily mistaken for recurrent compression, so the branches are sought and protected when the incision is made.

    • Lowe JB 3rd, Maggi SP, Mackinnon SE. The position of crossing branches of the medial antebrachial cutaneous nerve during cubital tunnel surgery in humans. Plast Reconstr Surg. 2004;114(3):692-696. PMID 15318047