An Unusual Cause of Ulnar Nerve Compression--Hayato Hirotani
A N U N U S U A L CAUSE OF U L N A R N E R V E COMPRESSION H A Y A T O H I R O T A N I , Kyoto, Japan SUMMARY A case of ulnar nerve compression is reported which was caused by anatomical abnormalities at the elbow. Ulnar nerve compression at the elbow has been k n o w n for almost a century since the first report by Panas (1878). A number of causative factors have been described anti discussed in the literature (Sunderland, 1969; Seddon, 1972; Apfelberg and Larsen, 1973). We have recently experienced a case canse~ by an unusual mechanism which, to. our knowledge, has not been described previously. CASE REPORT A 24-year-old housewife had noted weakness and paraesthesiae of the left ring and little fingers for two years. Flexion of the elbow was followed by numbness in the ulnar side of the left hand. She was right handed and gave no history of trauma. Family history was noncontributory. Physical examination revealed wasting and weakness of all the muscles innervated by the ulnar nerve accompanied by decreased pinprick sensation in the ulnar distribution of her left hand and fingers. 25 degrees flexion contracture and 20 degrees valgus deformity were present at the left elbow and 35 degrees flexion contracture and 35 degree~ valgus deformity at the right elbow. She was of short stature but with normal proportions. Her height was 138 centimetres, whereas the mean height for a Japanese 24-year-old female is 154.4 centimetres (Government Publication, 1972). There was shortening of the left leg. Roentgenographically, marked deformity of the elbow was observed, more on the left elbow than that on the right elbow (Figs. 1 and 2). The shafts of the humerus, radius and ulna were thin. There was no trochlea and where it should have been was a bony defect in the distal end of the humerus extending into the olecranon fossa. Both epicondyli of the humerus were poorly developed and the postcondylar groove was not seen in the axial views (Figs 3 and 4). The radius had no head, but instead a cone-shaped end which was displaced medially and proximally and seemed to be articulating with the defect in the humerus. In the left arm the ulna, with its hypoplastic olecranon, was also displaced medially and proximally.. A radiological skeletal survey showed no other abnormalities except for a dislocated left hip. Operation: The left ulnar nerve was explored at the elbow (Fig. 5). The ulnar nerve was compressed on the inner side of the elbow by the aponeuro~is of the flexor carpi ulnaris muscle which was originated solely from the olecranon. A fusiform thickening and induration of the nerve trunk were found immediately proximal to the compression site. The aponeurosis was cut and the compression was released. The medial cut edge was sutured to the medial condyle and the lateral cut end was left free. Epi- and perineurial neurolysis was performed. No transposition of the nerve was carried out. After 1½ months, sensation was returned to normal. Motor recovery reached the thumb adductor eight months after operation. One year after surgery, examination revealed normal sensation and motor function of the left hand. DISCUSSION Ulnar nerve compression at the elbow may be due to compression by the transverse fascial band bridging the two heads of the flexor carpi ulnaris muscle (Osborne, 1957 and 1970; Ho and Marmor, 1971: Apfelberg and Larsen, 1973).
266
The Hand~Vol. 7
No.
3
1975
A n Unusual Cause of Ulnar Nerve Compression--Hayato Hirotani
Fig. Fig. Fig. Fig.
1. 2. 3. 4.
X-ray X-ray X-ray X-ray
picture picture picture picture
of of of of
the the the the
left elbow, a-p view. right elbow, a-p view. left elbow, axial view. right elbow, axial view.
i"
Fig. 5. Operation. Fusiform thickening of the ulnar nerve is seen. The haemostat is indicating the compression site. T h e case presented here is very unusual but is caused by a similar mechanism. In this case, the muscle was forced against the distal end of the h u m e r u s due to displacement of the olecranon, f r o m which the muscle had its only origin. The aponeurosis of the muscle consequently compressed the nerve which was displaced to the inner side of the elbow. Valgus deformity and flexion of the elbow TI~e tta:~d
Vol. 7
No. 3 .
1975
267
An Unusual Cause o/ Ulnar Nerve Compression--Hayato Hirotani
may prevent the nerve f r 0 m ~ r e e movement, a feature contributing to the occurrence of compression neuritis. Although aplasia of the trochlea appearing in one.family was reported by Mead and Martin (1963), a search of the literature failed to find any instances of the skeletal o r muscular anomalies reported here. On the other hand, the literature pertaining to a muscle anomaly responsible for ulnar neuritis is sparse (Bateman, 1962; Vanderpool, Chalmers, Lamb and Whiston, 1968; Rolfsen, 1970; Seddon, 1972). Release of the nerve from the compression and heurolysis without transposition resulted in excellent recovery of nerve function. ACKNOWLEDGEMENT
The author would like to express his appreciation~t0 Professor Tetuo Ito, Department of Orthopaedic Surgery, Faculty of Medicine, Kyoto University, for helpful criticism and encouragement. !, REFERENCES
APFELBERG, D. B. and LARSON, S. J. (1973) Dynamic Anatomy Of The Ulnar Nerve At The Elbow. Plastic and Reconstructive Surgery, 51: 76-81. :.... BATEMAN, J. (1962) Trauma to Nerves in Limbs. Philadelphia and London, Saunders Co., p. 45. HO, K. C. and MARMOR, L. (1971) Entrapment of the Ulnar Nerve at the Elbow. American Journal of Surgery, 121: 355-356. MEAD, C. A. and MARTIN, M. (1963) Aplasia of the Trochlea--An Original Mutation. Journal of Bone and Joint Surgery, 45A: 379-383. OSBORNE, G. V. (1957) The surgical treatment of tardy ulnar neuritis. Journal of Bone and Joint Surgery, 39B: 782. OSBORNE, G. (1970) Compression Neuritis of the Ulnar Nerve at the Elbow. The Hand, 2: 10-13~ PANAS, J. (t878) Sur une Cause peu Connue De Paralysie Du Neff Cubital (1). Archives G6n6rales de M6dicine, 2: 5-22. ROLFSEN, L. (1970) Snapping Triceps Tendon With Ulnar Neuritis. Acta Orthopaedica Scandinavica, 41: 74-76. Section of Nutrition, Public Health Bureau, Ministry of Health and Welfare (1972). Physical Standards of Japanese People, Nutritional Survey in 1971. Japanese Government Publication, p. 60. SEDDON, H. J. (1972) Surgical Disorders Of the Peripheral Nerves. Edinburgh and London, Churchill Livingstone, p. 114. SUNDERLAND, S. (1968) Nerves and Nerve Injuries. Edinburgh and London, E. & S. Livingstone Ltd., p. 861. VANDERPOOL, D. W., CHALMERS, l., LAMB, D. W. and WHISTON, T. B. (t968) Peripheral Compression Lesions Of The Ulnar Nerve. Journal of Bone and Joint Surgery, 50B: 792-803.
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No. 3
1975
A N U N U S U A L CAUSE OF U L N A R N E R V E COMPRESSION H A Y A T O H I R O T A N I , Kyoto, Japan SUMMARY A case of ulnar nerve compression is reported which was caused by anatomical abnormalities at the elbow. Ulnar nerve compression at the elbow has been k n o w n for almost a century since the first report by Panas (1878). A number of causative factors have been described anti discussed in the literature (Sunderland, 1969; Seddon, 1972; Apfelberg and Larsen, 1973). We have recently experienced a case canse~ by an unusual mechanism which, to. our knowledge, has not been described previously. CASE REPORT A 24-year-old housewife had noted weakness and paraesthesiae of the left ring and little fingers for two years. Flexion of the elbow was followed by numbness in the ulnar side of the left hand. She was right handed and gave no history of trauma. Family history was noncontributory. Physical examination revealed wasting and weakness of all the muscles innervated by the ulnar nerve accompanied by decreased pinprick sensation in the ulnar distribution of her left hand and fingers. 25 degrees flexion contracture and 20 degrees valgus deformity were present at the left elbow and 35 degrees flexion contracture and 35 degree~ valgus deformity at the right elbow. She was of short stature but with normal proportions. Her height was 138 centimetres, whereas the mean height for a Japanese 24-year-old female is 154.4 centimetres (Government Publication, 1972). There was shortening of the left leg. Roentgenographically, marked deformity of the elbow was observed, more on the left elbow than that on the right elbow (Figs. 1 and 2). The shafts of the humerus, radius and ulna were thin. There was no trochlea and where it should have been was a bony defect in the distal end of the humerus extending into the olecranon fossa. Both epicondyli of the humerus were poorly developed and the postcondylar groove was not seen in the axial views (Figs 3 and 4). The radius had no head, but instead a cone-shaped end which was displaced medially and proximally and seemed to be articulating with the defect in the humerus. In the left arm the ulna, with its hypoplastic olecranon, was also displaced medially and proximally.. A radiological skeletal survey showed no other abnormalities except for a dislocated left hip. Operation: The left ulnar nerve was explored at the elbow (Fig. 5). The ulnar nerve was compressed on the inner side of the elbow by the aponeuro~is of the flexor carpi ulnaris muscle which was originated solely from the olecranon. A fusiform thickening and induration of the nerve trunk were found immediately proximal to the compression site. The aponeurosis was cut and the compression was released. The medial cut edge was sutured to the medial condyle and the lateral cut end was left free. Epi- and perineurial neurolysis was performed. No transposition of the nerve was carried out. After 1½ months, sensation was returned to normal. Motor recovery reached the thumb adductor eight months after operation. One year after surgery, examination revealed normal sensation and motor function of the left hand. DISCUSSION Ulnar nerve compression at the elbow may be due to compression by the transverse fascial band bridging the two heads of the flexor carpi ulnaris muscle (Osborne, 1957 and 1970; Ho and Marmor, 1971: Apfelberg and Larsen, 1973).
266
The Hand~Vol. 7
No.
3
1975
A n Unusual Cause of Ulnar Nerve Compression--Hayato Hirotani
Fig. Fig. Fig. Fig.
1. 2. 3. 4.
X-ray X-ray X-ray X-ray
picture picture picture picture
of of of of
the the the the
left elbow, a-p view. right elbow, a-p view. left elbow, axial view. right elbow, axial view.
i"
Fig. 5. Operation. Fusiform thickening of the ulnar nerve is seen. The haemostat is indicating the compression site. T h e case presented here is very unusual but is caused by a similar mechanism. In this case, the muscle was forced against the distal end of the h u m e r u s due to displacement of the olecranon, f r o m which the muscle had its only origin. The aponeurosis of the muscle consequently compressed the nerve which was displaced to the inner side of the elbow. Valgus deformity and flexion of the elbow TI~e tta:~d
Vol. 7
No. 3 .
1975
267
An Unusual Cause o/ Ulnar Nerve Compression--Hayato Hirotani
may prevent the nerve f r 0 m ~ r e e movement, a feature contributing to the occurrence of compression neuritis. Although aplasia of the trochlea appearing in one.family was reported by Mead and Martin (1963), a search of the literature failed to find any instances of the skeletal o r muscular anomalies reported here. On the other hand, the literature pertaining to a muscle anomaly responsible for ulnar neuritis is sparse (Bateman, 1962; Vanderpool, Chalmers, Lamb and Whiston, 1968; Rolfsen, 1970; Seddon, 1972). Release of the nerve from the compression and heurolysis without transposition resulted in excellent recovery of nerve function. ACKNOWLEDGEMENT
The author would like to express his appreciation~t0 Professor Tetuo Ito, Department of Orthopaedic Surgery, Faculty of Medicine, Kyoto University, for helpful criticism and encouragement. !, REFERENCES
APFELBERG, D. B. and LARSON, S. J. (1973) Dynamic Anatomy Of The Ulnar Nerve At The Elbow. Plastic and Reconstructive Surgery, 51: 76-81. :.... BATEMAN, J. (1962) Trauma to Nerves in Limbs. Philadelphia and London, Saunders Co., p. 45. HO, K. C. and MARMOR, L. (1971) Entrapment of the Ulnar Nerve at the Elbow. American Journal of Surgery, 121: 355-356. MEAD, C. A. and MARTIN, M. (1963) Aplasia of the Trochlea--An Original Mutation. Journal of Bone and Joint Surgery, 45A: 379-383. OSBORNE, G. V. (1957) The surgical treatment of tardy ulnar neuritis. Journal of Bone and Joint Surgery, 39B: 782. OSBORNE, G. (1970) Compression Neuritis of the Ulnar Nerve at the Elbow. The Hand, 2: 10-13~ PANAS, J. (t878) Sur une Cause peu Connue De Paralysie Du Neff Cubital (1). Archives G6n6rales de M6dicine, 2: 5-22. ROLFSEN, L. (1970) Snapping Triceps Tendon With Ulnar Neuritis. Acta Orthopaedica Scandinavica, 41: 74-76. Section of Nutrition, Public Health Bureau, Ministry of Health and Welfare (1972). Physical Standards of Japanese People, Nutritional Survey in 1971. Japanese Government Publication, p. 60. SEDDON, H. J. (1972) Surgical Disorders Of the Peripheral Nerves. Edinburgh and London, Churchill Livingstone, p. 114. SUNDERLAND, S. (1968) Nerves and Nerve Injuries. Edinburgh and London, E. & S. Livingstone Ltd., p. 861. VANDERPOOL, D. W., CHALMERS, l., LAMB, D. W. and WHISTON, T. B. (t968) Peripheral Compression Lesions Of The Ulnar Nerve. Journal of Bone and Joint Surgery, 50B: 792-803.
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1975
