Nobuta S, Okuno H, Hatta T, Sato R, Itoi E.
Clinical Features of Ulnar Tunnel Syndrome and the Diagnostic Value of Nerve Conduction Measurements.
Prog Rehabil Med. 2021;6:20210010. doi: 10.2490/prm.20210010. Epub 2021 Feb 13.
Abstract/Text
OBJECTIVES: The purposes of this study were to assess the clinical features of ulnar tunnel syndrome (UTS) and to investigate the diagnostic value of nerve conduction measurements for UTS.
METHODS: Eighteen patients with UTS were reviewed retrospectively. Fifteen patients had intrinsic muscle atrophy and motor weakness, and 15 had numbness with hypesthesia. The compound muscle action potentials (CMAPs) from the first dorsal interosseous (FDI) muscle and the abductor digiti minimi (ADM) muscle and the sensory nerve action potential (SNAP) from the little finger were recorded and analyzed. All patients underwent ulnar tunnel release surgery and neurolysis. Static two-point discrimination test results and pinch strengths were assessed before and after surgery.
RESULTS: Before surgery, FDI-CMAP was recorded in 17 patients, and ADM-CMAP in 16, and all showed delayed latency and/or low amplitude. SNAP was recorded in eight patients and two showed delayed latency. The causes of ulnar nerve lesions were ganglion in five patients, traumatic adhesion in four, ulnar artery aberrancy in four, pisohamate arch in three, anomalous muscle in one, and ulnar vein varix in one. The sites of the lesions were in zone 1 of the ulnar tunnel anatomy in 12 patients, in zone 2 in 2, and in zones 1 and 2 in 4. After surgery, all patients obtained recovery of motor function and sensation; however, postoperative FDI-CMAP and ADM-CMAP did not improve to the normal range.
CONCLUSIONS: The causes of UTS were ganglion, traumatic adhesion, ulnar artery aberrancy, and pisohamate arch. Both FDI-CMAP and ADM-CMAP were valuable for electrophysiological diagnosis of UTS.
©2021 The Japanese Association of Rehabilitation Medicine.
Guyon FJC: Note sur une disposition anatomique propre a la face anterieure de la region du poignet et non encore decrite. Bull Soc Anat Paris 1861;6:184-186.
Hunt JR: Occupation neuritis of the deep palmar branch of the ulnar nerve: A well defined clinical type of professional palsy of the hand. J Nerv Ment Dis 1908;35:673-689.
DUPONT C, CLOUTIER GE, PREVOST Y, DION MA.
ULNAR-TUNNEL SYNDROME AT THE WRIST. A REPORT OF FOUR CASES ULNAR-NERVE COMPRESSION AT THE WRIST.
J Bone Joint Surg Am. 1965 Jun;47:757-61.
Abstract/Text
Gross MS, Gelberman RH.
The anatomy of the distal ulnar tunnel.
Clin Orthop Relat Res. 1985 Jun;(196):238-47.
Abstract/Text
The distal ulnar tunnel is a region of the wrist 4-4.5 cm in length in which the ulnar nerve is particularly vulnerable to external compression. The relation of the internal topography of the nerve to the structures comprising the tunnel provides a basis for dividing the tunnel into three zones. Zone 1 is that portion of the tunnel proximal to the bifurcation of the ulnar nerve. Zone 2 encompasses the deep motor branch of the nerve, and Zone 3 surrounds the superficial branch. A review of the literature of ulnar nerve compression lesions confirmed expectations based on the regional anatomy. Zone 1 lesions included all (39) cases of combined motor and sensory deficits, one case of pure motor paralysis, and seven cases of sensory deficits. All Zone 2 lesions (36 cases) resulted in paralysis of the intrinsic muscles. Whether or not the hypothenar muscles were affected was dependent upon the location of the lesions within Zone 2. Zone 3 lesions caused sensory deficits only. Combined motor and sensory loss was most often caused by compression from deep to the nerve, while pure sensory deficits were a result of compression lesions lying superficial to the nerve.
Shea JD, McClain EJ.
Ulnar-nerve compression syndromes at and below the wrist.
J Bone Joint Surg Am. 1969 Sep;51(6):1095-103.
Abstract/Text
Uriburu IJ, Morchio FJ, Marin JC.
Compression syndrome of the deep motor branch of the ulnar nerve. (Piso-Hamate Hiatus syndrome).
J Bone Joint Surg Am. 1976 Jan;58(1):145-7.
Abstract/Text
津下健哉，山河 剛，稲垣正治 ほか：Ulnar tunnel syndromeの3例．中部整災誌 1967;10：203-206.
堀内行雄，井口 傑：尺骨管症候群の手術療法．MB Orthopaedics 1995;8：75-83.
池上博泰：尺骨管症候群．MB Orthopaedics 2009;22：51-57.
楢崎慎二、橋詰博行：Guyon管症候群．整形・災害外科 2008;51：533-537.
Murata K, Shih JT, Tsai TM.
Causes of ulnar tunnel syndrome: a retrospective study of 31 subjects.
J Hand Surg Am. 2003 Jul;28(4):647-51. doi: 10.1016/s0363-5023(03)00147-3.
Abstract/Text
PURPOSE: The purposes of this study were to determine the distribution of causes and sites of nerve compression in the ulnar tunnel (Guyon's canal), and investigate the relationship between ulnar tunnel syndrome (UTS) and other conditions associated with it.
METHODS: We performed a retrospective review of 31 patients diagnosed with and treated for UTS to determine the most common cause of compression and the sites of compression, systemic illnesses associated with UTS, and postoperative results.
RESULTS: The cause of ulnar nerve compression was idiopathic in 14, trauma in 8, a thrombosis in 2, proliferation of synovium in 2, a prominent hook of the hamate in 1, a schwannoma in 1, postoperative swelling in 1, an aberrant fibrous band in 1, and a ganglion in 1. The sites of compression were classified into 3 zones. Twenty-eight cases had compression in zone 1, 6 in zone 2, and 19 in zone 3. Seventeen cases (55%) had compression in more than 1 zone. Twenty-two cases (71%) were associated with carpal tunnel syndrome (CTS). Twelve (86%) of the 14 idiopathic UTS cases were associated with CTS. The relationship between idiopathic UTS and CTS was not statistically significant. Six cases were associated with diabetes mellitus.
CONCLUSIONS: The most common cause of UTS in our series was idiopathic. Most idiopathic UTS cases were associated with CTS. The clinical symptoms of UTS improved after surgery in all cases. Therefore because of the presence of multiple compression sites of the ulnar nerve in the hand, for UTS patients we believe that the release of Guyon's canal and/or the pisohamate tunnel is an effective way not only to relieve symptoms but also to determine the real cause of compression.
信田進吾：Guyon管症候群．中村耕三総編集．加藤博之専門編集．整形外科臨床パサージュ 5 手・肘の痛みクリニカルプラクテイス．中山書店，2010;309-313．.
立花新太郎，長野 昭，落合直之 ほか：尺骨神経管症候群―自験47例の臨床的検討．日手会誌 1985;2：180-184.
伊藤恵康，村上隆一，岡 義範 ほか：Ulnar tunnel syndrome. 整形外科 1978;29：1438-1441.
Zeiss J, Jakab E, Khimji T, Imbriglia J.
The ulnar tunnel at the wrist (Guyon's canal): normal MR anatomy and variants.
AJR Am J Roentgenol. 1992 May;158(5):1081-5. doi: 10.2214/ajr.158.5.1566671.
Abstract/Text
The ulnar tunnel (Guyon's canal) is a fibroosseous tunnel along the anteromedial portion of the wrist that contains the ulnar nerve and artery. As with the adjacent carpal tunnel, its main clinical significance is that it may cause nerve compression. The purpose of this study was to determine whether the anatomy of this area could be depicted in sufficient detail by MR imaging for MR to be useful in the evaluation of patients with ulnar neuropathy. MR studies of 36 wrists of volunteers were reviewed with attention to the size and shape of the canal, its anatomic boundaries, the presence of anomalous muscles, the size and bifurcation of the ulnar nerve, and the presence of a fibrous or muscular arch overlying the deep motor branch of the ulnar nerve. T1-weighted transverse MR images of 3-mm-thick sections were obtained by using either an extremity coil or dedicated wrist coil. Excellent anatomic delineation was achieved. The boundaries and shape of the canal varied from proximal to distal, but no statistical differences were present in the mean cross-sectional area of the canal. Anomalous muscles were present in the canal in nine (25%) of 36 wrists; six (67%) of the nine were bilateral. The ulnar nerve had a mean diameter of 3 mm and bifurcated an average distance of 12 mm from the proximal margin of the pisiform bone. Delineation of the fibromuscular arch at the origin of the flexor digiti minimi brevis muscle was limited by imager resolution, but 50% were judged to be fibrous and 50% to be muscular. Our results show that MR images depict the ulnar tunnel in excellent detail. Since those structures associated with ulnar neuropathy are clearly delineated by MR, the procedure should be useful in the evaluation of patients suspected of having ulnar nerve compression within the tunnel.
Cowdery SR, Preston DC, Herrmann DN, Logigian EL.
Electrodiagnosis of ulnar neuropathy at the wrist: conduction block versus traditional tests.
Neurology. 2002 Aug 13;59(3):420-7. doi: 10.1212/wnl.59.3.420.
Abstract/Text
BACKGROUND: Compared to ulnar neuropathy at the elbow (UNE), ulnar neuropathy at the wrist (UNW) is rarer and more difficult to localize with routine electrophysiologic studies.
METHODS: By stimulating the ulnar nerve at the wrist and palm, and recording from first dorsal interosseous (FDI), the sensitivity and specificity of conduction block (CB) and slow conduction velocity (CV) of FDI fibers across the wrist was compared to traditional electrodiagnostic techniques for localization of UNW. Twenty patients with clinically defined UNW (due mainly to wrist trauma), 30 normal controls, and 20 disease controls with severe (n = 10) and mild (n = 10) UNE were evaluated prospectively. The upper (mean +2.5 SD) and lower (mean -2.5 SD) limits for all measurements were derived from the normal controls.
RESULTS: The UNW patients showed: slow wrist-palm FDI CV (<37 m/s) in 16 (80%); definite or probable CB in 14 (70%); prolonged distal latency (DL) to FDI (>4.5 milliseconds) in 12 (60%), to ulnar-innervated palmar interosseous (PI) versus median-innervated lumbrical (L) in 12 (60%), and to abductor digiti minimi (ADM) in 11 (55%). However, only CB and slow wrist-palm FDI CV (<37 m/s) were specific for UNW; prolonged DL to FDI was found in 4 patients (40%), to ADM in 4 patients (40%), and to PI in 1 patient (10%) with severe UNE. Overall, CB or slow wrist-palm FDI CV was present in 19 patients with UNW (95%). EMG failed to differentiate UNW from UNE, because forearm ulnar-innervated muscles were typically normal in UNW, but also often normal in mild UNE.
CONCLUSIONS: In UNW, an additional palmar stimulation site improves electrodiagnostic yield, and demonstrates that CB is an important cause of muscle weakness.
Hatori M, Sakurai M, Miyasaka Y et al.: Electrodiagnosis of ulnar tunnel syndrome by inching technique. J Jpn Soc Surg Hand 1989;6:346-350.
小平 聡，児玉忠雄，平瀬雄一 ほか：尺骨神経管症候群17例の検討．日手会誌 2007;24：185-188.
