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Ulnar nerve compression in Guyon's canal due to a haemangioma of the ulnar artery
ULNAR
NERVE COMPRESSION I N G U Y O N ' S C A N A L D U E TO A HAEMANGIOMA OF THE ULNAR ARTERY H. KOCH, E HAAS and G. PIERER
From the Division of Plastic Surgery, Department of Surgery, Karl-Franzens-University Graz Medical School, Graz, Austria A case of ulnar nerve compression in Guyon's canal due to a haemangioma of the ulnar artery is reported.
Journal of Hand Surgery (British and European Volume, 1998) 23B." 2:242-244 Most cases of ulnar nerve compression in Guyon's canal are due to ganglia. Other tumours or tumourlike masses causing ulnar compression at Guyon's canal are lipomas, giant cell tumours, intraneural cysts, metastases, synovitis or aneurysms of the ulnar artery. This report is, to the best of our knowledge, the first on ulnar neuropathy in the wrist caused by a haemangioma of the ulnar artery. CASE R E P O R T
A 29-year-old carpenter presented with diminished sensation in the little finger and the ulnar aspect of the ring finger. Atrophy of the first web space was evident. There was a history of repeated occupational use of the hypothenar eminence as a hammer and he described a sudden dull pain in the hypothenar region which he had felt when he had been lifting a heavy wooden panel. Clinical examination revealed diminished sensation distal to Guyon's canal, inability to cross the fingers, incipient clawing of the ring and little fingers, and weakness of the flexor digiti minimi muscle. Froment's sign was positive. There were no signs of ischaemia. An MRI scan, done before referral to our department, led to the diagnosis of an ulnar artery aneurysm with a thickened thrombotic-fibrotic wall. Nerve conduction velocity of the ulnar nerve was reduced. Distal latency to the first dorsal interosseus muscle showed a significant delay, whereas the latency to the abductor digiti minimi muscle was normal. Surgery was carried out assuming that ulnar nerve compression syndrome was due to an aneurysm of the ulnar artery. A swelling of the ulnar artery 25 mm in diameter was found (Fig 1). The ulnar nerve showed signs of external compression due to the tumour. The affected segment of the artery was resected, and repaired using an interpositional vein graft. Histological examination of the resected specimen showed a well circumscribed proliferation of thin-walled vessels with flattened endothelial cells. The central part consisted of ectatic, blood-filled vessels with blood within the extravascular spaces (Fig 2). The diagnosis of an acquired ulnar artery haemangioma with central bleeding was established. The postoperative course was uneventful, and the symptoms had resolved within 4 weeks. One year later, he has regained full hand function and is free of symptoms. Ultrasonography shows a patent ulnar artery with no evidence of recurrence of the haemangioma. Nerve conduction velocity and distal latency
Fig 1
Intraoperative photograph showing a swelling of the ulnar artery 25 mm in diameter.
Fig 2
Photomicrograph showing a proliferation of thin-walled vessels with flattened endothelial cells. Note the blood within the extravascular spaces.
to the first dorsal interosseus muscle have returned to normal. DISCUSSION Compression of the ulnar nerve at Guyon's canal is much less frequent than other nerve entrapment syndromes, but 242
243
ULNARNERVECOMPRESSION it c a n lead to severe i m p a i r m e n t of h a n d function. It is frequently associated with pathological structures in G u y o n ' s canal. A ganglion is the m o s t c o m m o n o f these ( F o u c h e r et al, 1993; K u s c h n e r et al, 1988; Seddon, 1952; Strickland a n d Steichen, 1977; Trevaskis et al, 1967). O t h e r t u m o u r s causing distal u l n a r c o m p r e s s i o n syndromes are g i a n t cell t u m o u r s (Milberg a n d Kleinert, 1980; Rafecas et al, 1988; R e n g a c h a r y a n d A r j u n a n , 1981), lipomas ( M c F a r l a n d a n d Hoffer, 1971; Zahrawi, 1984), i n t r a n e u r a l cysts (Bowers a n d Doppelt, 1979), a n d metastases ( W i t t h a u t e t al, 1994). A b n o r m a l muscles (Sfilgeback, 1977), a b n o r m a l nerve or t e n d o n a n a t o m y ( O ' H a r a a n d Stone, 1988; Papierski, 1996; Z o o k et al, 1988), a n d synovitis (Budny et al, 1992) have also been reported to cause distal u l n a r nerve e n t r a p ment. Distal u l n a r compression s y n d r o m e can also be caused by activities such as bicycle riding for long periods in the absence of a b n o r m a l structures in G u y o n ' s c a n a l (Ogino et al, 1990). U l n a r nerve involvement at the wrist m a y also occur after i n j u r y either as a result of o e d e m a (Leslie, 1980) or true or false a n e u r y s m of the u l n a r artery (Axe a n d M c C l a i n , 1986; K a l i s m a n et al, 1982; K a y et al, 1988). I n m o s t cases, however, the m a i n s y m p t o m o f a n e u r y s m o f the u l n a r artery is ischaemia (Harris et al, 1990), which m a y follow h y p o t h e n a r h a m m e r s y n d r o m e (Corm et al, 1970). I n o u r patient, there was a typical history o f repeated use o f the h y p o t h e n a r eminence as a h a m m e r resulting in s y m p t o m s of u l n a r nerve e n t r a p m e n t . There was also a history of a s u d d e n dull p a i n in the h y p o t h e n a r eminence u n d e r stress. Together with the M R I findings, this led to the diagnosis o f u l n a r artery a n e u r y s m . There were n o signs of digital ischaemia a n d we a t t r i b u t e d this to sufficient collateral b l o o d supply. Surprisingly, histological e v a l u a t i o n o f the arterial specimen after resection revealed a h a e m a n g i o m a o f the u l n a r artery with central bleeding. T a k i n g into a c c o u n t the history, central bleeding caused by t r a u m a could have resulted in expansion of the h a e m a n g i o m a leading in t u r n to u l n a r nerve compression. A case with a similar aetiology involving the femoral nerve has been reported by C o p p o l a (1974). H a e m a n g i o m a s involving nerves with (Bilge et al, 1989; C o p p o l a , 1974; Linde a n d Gaab, 1982; Patel et al, 1986) or w i t h o u t ( K o n a n d Vuursteen, 1981) compression s y m p t o m s have been reported before, b u t to o u r knowledge ours is the first report of nerve e n t r a p m e n t due to a n arterial h a e m a n g i o m a . W h e n there are pathological changes in the u l n a r artery such as a n e u r y s m s or t u m o u r s the involved segm e n t should be resected. Since in most cases the u l n a r artery a n d the superficial p a l m a r arch are the m a i n sources o f arterial b l o o d supply to the fingers ( C o l e m a n a n d A n s o n , 1961), r e c o n s t r u c t i o n of the artery after resection is mandatory. Even t h o u g h there m a y be a sufficient collateral blood supply via the radial artery a n d digital ischaemia might n o t be present d u r i n g a modified Allen's test or immediately after surgery, b l o o d
supply to the fingers after ligation of the u l n a r artery may be insufficient to prevent cold intolerance. Therefore, whenever possible, the u l n a r artery should be reconstructed using a n i n t e r p o s i t i o n a l graft. E n d - t o - e n d a n a s t o m o s i s w i t h o u t a n i n t e r p o s i t i o n a l graft increases the risk o f recurrence due to incomplete resection ( K a l i s m a n et al, 1982). F o r this reason, reconstruction should be accomplished using autologous interpositional graffs, which have been shown to have good patency rates (Harris et al, 1990).
Acknowledgements The authors express their sincere thanks to K. H. Preissegger, Institute of Pathology, Karl-Franzens-UniversityGraz Medical School, for the histopathological examinationof the surgical specimenand to Professor E. Scharnagl,Divisionof Plastic Surgery,Departmentof Surgery,Karl-FranzensUniversity Graz Medical School for suggestionand advice throughout this investigation.
References AxeMJ, McClalnEJ (1986).Completeinvolvementof the ulnarnervesecondary to an ulnarartery aneurysm.AmericanJournalof Sports Medicine,14: 178-180. BilgeT, KayaA, AlatliM, BilgeS, AlatliC (1989).Hemangiomaof the pemneal nerve: Case report and review of the literature. Neurosurgery, 25: 649-652. Bowers WH, DoppeltSH (t979). Compressionof the deep branchof the ulnar nerve by an intraneuralcyst. Journal of Bone and Joint Surgery,61A: 612 613. BndnyPG, Regan PJ, Roberts AH 0992). Localizednodularsynovitis:A rare cause of ulnar nervecompressionin Guyon'scanal. Journal of Hand Surgery,17A:663-664. ColemanSS, AnsonBJ (1961).Arterialpatternsin the handbasedupona study of 650 specimens.Surgery,Gynecologyand Obstetrics,113:409424. ConnJ, BerganJJ, BellJL (1970).Hypothenarhammersyndrome:Posttraumatic digitalischemia.Surgery,68:1122-1128. Coppola AR (1974). Femoral neuropathy. Virginia Medical Monthly, 10h 854-855. Foucher G, Berard V, SniderG, LenobleE, ConstantinescoA (1993). Distal ulnarnerveentrapmentdue to tumorsof Guyon'scanal:A seriesof ten cases. HandchirurgieMikrochirurgiePlastischeChirurgie,25: 61-65. Harris EJ, Taylor LM, Edwards JM, Mills JL, Porter JM (1990). Surgical treatmentof distalulnararteryaneurysm.AmericanJournalof Surgery, 159:527-530. KalismanM, LabordeK, WolffTW (1982).Ulnarnervecompressionsecondary to ulnar artery false aneurysmat the Guyon'scanal. Journal of Hand Surgery,7:137 139. Kay PR, Abraham JS, Davies DRA, Bertfield H (t988). Ulnar artery aneurysmsafter injurymimickingacute infectionin the hand. Injury, 19: 402404. Kon M, VuursteenPJ (1981). An intraneuralhemangiomaof a digitalnerve: Case report. Journalof HandSurgery,6: 357~58. KuschnerSH, GelbermannRH, JenningsC (1988).Ulnarnervecompressionat the wrist.Journalof HandSurgery,13A:57%580. Leslie IJ (1980). Compressionof the deep branch of the ulnar nerve due to oedemaof the band.The Hand, 12:271-272. Linde U, Gaab MR (1982). Hfimangiomdes Nervus ulnaris. Handchirurgie MikrocbirurgiePlastischeChirurgie,t4: 2052. McFarlandGB, HofferMM (1971).Paralysisof the intrinsicmusclesof the hand secondary to lipoma in Guyon'stunnel. Journal of Bone and Joint Surgery,53A:375-376. MilbergP, KleinertHE (1980).Giantcelltumorcompressionof the deepbranch of the ulnarnerve.Annalsof PlasticSurgery,4: 426-429. Ogino T, MinamiA, Kato H, Takahata S (1990). Ulnar nerveneuropathyat the wrist. Handchirurgie Mikrochirurgie Plastische Chirurgie, 22: 304-308. O'Hara JJ, Stone JH (1988). Ulnar neuropathy at the wrist associated with aberrant flexorcarpi ulnarisinsertion.Journal of Hand Surgery, 13A: 38~384. Papierski P (1996). Ulnar neuropathyat the wrist associated with a recurrent branchthroughthe flexorcarpiulnaristendon.Journalof HandSurgery, 21B: 347 348. Patel CB, TsaiTM, KleinertHE (1986). Hemangiomaof the mediannerve:A report of two cases.Journalof Hand Surgery,11A:76 79.
244 Rafecas JC, Daube JR, Ehmann RL (1988). Deep branch ulnar neuropathy due to giant cell tumor: Report of a case. Neurology, 38: 327-329. Rengachary SS, Arjunan K (1981). Compression of the ulnar nerve in Guyon's canal by a soft tissue giant cell tumor. Neurosurgery, 8: 400M05. Sfilgeback S (1977). Ulnar tunnel syndrome caused by anomalous muscles. Scandinavian Journal of Plastic and Reconstructive Surgery, 11: 255-258. Seddon HJ (1952). Carpal ganglion as a cause of paralysis of the deep branch of the ulnar nerve. Journal of Bone and Joint Surgery, 34B: 386 390. Strickland JW, Steichen JB (1977). Nerve tumors of the hand and forearm. Journal of Hand Surgery, 2: 2 8 5 2 9 1 . Trevaskis AE, Tilly D, Marcks KM, Heffernan A H (1967). Loss of nerve function in the hand caused by ganglions. Plastic and Reconstructive Surgery, 39:97 100. Witthaut J, Steffens K, Koob E (1994). Ungew6hnlicher Fall einer Metastase in die Weichteile der Hohlhand mit Kompression des N. medianns und N.
THE J O U R N A L OF H A N D SURGERY VOL. 23B No. 2 A P R I L 1998 ulnaris in Folge eines Nierenkarzinoms. Handchirurgie Mikrochirurgie Plastische Chirurgie, 26:137 140. Zahrawi F (1984). Acute compression ulnar neuropathy at Guyon's canal resulting from lipoma. Journal of H a n d Surgery, 9A: 238-240. Zook EG, Kucan JO, Guy RJ (1988). Palmar wrist pain caused by ulnar nerve entrapment in the flexor carpi ulnaris tendon. Journal of H a n d Surgery, 13A: 732-735.
Received: 30 May 1997 Accepted after revision: 3 November 1997 H. Koch MD, Division of Plastic Surgery,Department of Surgery,KarI-Franzens-University Graz Medical School, A-8036Graz, Austria. © 1998The British Society for Surgery of the Hand
NERVE COMPRESSION I N G U Y O N ' S C A N A L D U E TO A HAEMANGIOMA OF THE ULNAR ARTERY H. KOCH, E HAAS and G. PIERER
From the Division of Plastic Surgery, Department of Surgery, Karl-Franzens-University Graz Medical School, Graz, Austria A case of ulnar nerve compression in Guyon's canal due to a haemangioma of the ulnar artery is reported.
Journal of Hand Surgery (British and European Volume, 1998) 23B." 2:242-244 Most cases of ulnar nerve compression in Guyon's canal are due to ganglia. Other tumours or tumourlike masses causing ulnar compression at Guyon's canal are lipomas, giant cell tumours, intraneural cysts, metastases, synovitis or aneurysms of the ulnar artery. This report is, to the best of our knowledge, the first on ulnar neuropathy in the wrist caused by a haemangioma of the ulnar artery. CASE R E P O R T
A 29-year-old carpenter presented with diminished sensation in the little finger and the ulnar aspect of the ring finger. Atrophy of the first web space was evident. There was a history of repeated occupational use of the hypothenar eminence as a hammer and he described a sudden dull pain in the hypothenar region which he had felt when he had been lifting a heavy wooden panel. Clinical examination revealed diminished sensation distal to Guyon's canal, inability to cross the fingers, incipient clawing of the ring and little fingers, and weakness of the flexor digiti minimi muscle. Froment's sign was positive. There were no signs of ischaemia. An MRI scan, done before referral to our department, led to the diagnosis of an ulnar artery aneurysm with a thickened thrombotic-fibrotic wall. Nerve conduction velocity of the ulnar nerve was reduced. Distal latency to the first dorsal interosseus muscle showed a significant delay, whereas the latency to the abductor digiti minimi muscle was normal. Surgery was carried out assuming that ulnar nerve compression syndrome was due to an aneurysm of the ulnar artery. A swelling of the ulnar artery 25 mm in diameter was found (Fig 1). The ulnar nerve showed signs of external compression due to the tumour. The affected segment of the artery was resected, and repaired using an interpositional vein graft. Histological examination of the resected specimen showed a well circumscribed proliferation of thin-walled vessels with flattened endothelial cells. The central part consisted of ectatic, blood-filled vessels with blood within the extravascular spaces (Fig 2). The diagnosis of an acquired ulnar artery haemangioma with central bleeding was established. The postoperative course was uneventful, and the symptoms had resolved within 4 weeks. One year later, he has regained full hand function and is free of symptoms. Ultrasonography shows a patent ulnar artery with no evidence of recurrence of the haemangioma. Nerve conduction velocity and distal latency
Fig 1
Intraoperative photograph showing a swelling of the ulnar artery 25 mm in diameter.
Fig 2
Photomicrograph showing a proliferation of thin-walled vessels with flattened endothelial cells. Note the blood within the extravascular spaces.
to the first dorsal interosseus muscle have returned to normal. DISCUSSION Compression of the ulnar nerve at Guyon's canal is much less frequent than other nerve entrapment syndromes, but 242
243
ULNARNERVECOMPRESSION it c a n lead to severe i m p a i r m e n t of h a n d function. It is frequently associated with pathological structures in G u y o n ' s canal. A ganglion is the m o s t c o m m o n o f these ( F o u c h e r et al, 1993; K u s c h n e r et al, 1988; Seddon, 1952; Strickland a n d Steichen, 1977; Trevaskis et al, 1967). O t h e r t u m o u r s causing distal u l n a r c o m p r e s s i o n syndromes are g i a n t cell t u m o u r s (Milberg a n d Kleinert, 1980; Rafecas et al, 1988; R e n g a c h a r y a n d A r j u n a n , 1981), lipomas ( M c F a r l a n d a n d Hoffer, 1971; Zahrawi, 1984), i n t r a n e u r a l cysts (Bowers a n d Doppelt, 1979), a n d metastases ( W i t t h a u t e t al, 1994). A b n o r m a l muscles (Sfilgeback, 1977), a b n o r m a l nerve or t e n d o n a n a t o m y ( O ' H a r a a n d Stone, 1988; Papierski, 1996; Z o o k et al, 1988), a n d synovitis (Budny et al, 1992) have also been reported to cause distal u l n a r nerve e n t r a p ment. Distal u l n a r compression s y n d r o m e can also be caused by activities such as bicycle riding for long periods in the absence of a b n o r m a l structures in G u y o n ' s c a n a l (Ogino et al, 1990). U l n a r nerve involvement at the wrist m a y also occur after i n j u r y either as a result of o e d e m a (Leslie, 1980) or true or false a n e u r y s m of the u l n a r artery (Axe a n d M c C l a i n , 1986; K a l i s m a n et al, 1982; K a y et al, 1988). I n m o s t cases, however, the m a i n s y m p t o m o f a n e u r y s m o f the u l n a r artery is ischaemia (Harris et al, 1990), which m a y follow h y p o t h e n a r h a m m e r s y n d r o m e (Corm et al, 1970). I n o u r patient, there was a typical history o f repeated use o f the h y p o t h e n a r eminence as a h a m m e r resulting in s y m p t o m s of u l n a r nerve e n t r a p m e n t . There was also a history of a s u d d e n dull p a i n in the h y p o t h e n a r eminence u n d e r stress. Together with the M R I findings, this led to the diagnosis o f u l n a r artery a n e u r y s m . There were n o signs of digital ischaemia a n d we a t t r i b u t e d this to sufficient collateral b l o o d supply. Surprisingly, histological e v a l u a t i o n o f the arterial specimen after resection revealed a h a e m a n g i o m a o f the u l n a r artery with central bleeding. T a k i n g into a c c o u n t the history, central bleeding caused by t r a u m a could have resulted in expansion of the h a e m a n g i o m a leading in t u r n to u l n a r nerve compression. A case with a similar aetiology involving the femoral nerve has been reported by C o p p o l a (1974). H a e m a n g i o m a s involving nerves with (Bilge et al, 1989; C o p p o l a , 1974; Linde a n d Gaab, 1982; Patel et al, 1986) or w i t h o u t ( K o n a n d Vuursteen, 1981) compression s y m p t o m s have been reported before, b u t to o u r knowledge ours is the first report of nerve e n t r a p m e n t due to a n arterial h a e m a n g i o m a . W h e n there are pathological changes in the u l n a r artery such as a n e u r y s m s or t u m o u r s the involved segm e n t should be resected. Since in most cases the u l n a r artery a n d the superficial p a l m a r arch are the m a i n sources o f arterial b l o o d supply to the fingers ( C o l e m a n a n d A n s o n , 1961), r e c o n s t r u c t i o n of the artery after resection is mandatory. Even t h o u g h there m a y be a sufficient collateral blood supply via the radial artery a n d digital ischaemia might n o t be present d u r i n g a modified Allen's test or immediately after surgery, b l o o d
supply to the fingers after ligation of the u l n a r artery may be insufficient to prevent cold intolerance. Therefore, whenever possible, the u l n a r artery should be reconstructed using a n i n t e r p o s i t i o n a l graft. E n d - t o - e n d a n a s t o m o s i s w i t h o u t a n i n t e r p o s i t i o n a l graft increases the risk o f recurrence due to incomplete resection ( K a l i s m a n et al, 1982). F o r this reason, reconstruction should be accomplished using autologous interpositional graffs, which have been shown to have good patency rates (Harris et al, 1990).
Acknowledgements The authors express their sincere thanks to K. H. Preissegger, Institute of Pathology, Karl-Franzens-UniversityGraz Medical School, for the histopathological examinationof the surgical specimenand to Professor E. Scharnagl,Divisionof Plastic Surgery,Departmentof Surgery,Karl-FranzensUniversity Graz Medical School for suggestionand advice throughout this investigation.
References AxeMJ, McClalnEJ (1986).Completeinvolvementof the ulnarnervesecondary to an ulnarartery aneurysm.AmericanJournalof Sports Medicine,14: 178-180. BilgeT, KayaA, AlatliM, BilgeS, AlatliC (1989).Hemangiomaof the pemneal nerve: Case report and review of the literature. Neurosurgery, 25: 649-652. Bowers WH, DoppeltSH (t979). Compressionof the deep branchof the ulnar nerve by an intraneuralcyst. Journal of Bone and Joint Surgery,61A: 612 613. BndnyPG, Regan PJ, Roberts AH 0992). Localizednodularsynovitis:A rare cause of ulnar nervecompressionin Guyon'scanal. Journal of Hand Surgery,17A:663-664. ColemanSS, AnsonBJ (1961).Arterialpatternsin the handbasedupona study of 650 specimens.Surgery,Gynecologyand Obstetrics,113:409424. ConnJ, BerganJJ, BellJL (1970).Hypothenarhammersyndrome:Posttraumatic digitalischemia.Surgery,68:1122-1128. Coppola AR (1974). Femoral neuropathy. Virginia Medical Monthly, 10h 854-855. Foucher G, Berard V, SniderG, LenobleE, ConstantinescoA (1993). Distal ulnarnerveentrapmentdue to tumorsof Guyon'scanal:A seriesof ten cases. HandchirurgieMikrochirurgiePlastischeChirurgie,25: 61-65. Harris EJ, Taylor LM, Edwards JM, Mills JL, Porter JM (1990). Surgical treatmentof distalulnararteryaneurysm.AmericanJournalof Surgery, 159:527-530. KalismanM, LabordeK, WolffTW (1982).Ulnarnervecompressionsecondary to ulnar artery false aneurysmat the Guyon'scanal. Journal of Hand Surgery,7:137 139. Kay PR, Abraham JS, Davies DRA, Bertfield H (t988). Ulnar artery aneurysmsafter injurymimickingacute infectionin the hand. Injury, 19: 402404. Kon M, VuursteenPJ (1981). An intraneuralhemangiomaof a digitalnerve: Case report. Journalof HandSurgery,6: 357~58. KuschnerSH, GelbermannRH, JenningsC (1988).Ulnarnervecompressionat the wrist.Journalof HandSurgery,13A:57%580. Leslie IJ (1980). Compressionof the deep branch of the ulnar nerve due to oedemaof the band.The Hand, 12:271-272. Linde U, Gaab MR (1982). Hfimangiomdes Nervus ulnaris. Handchirurgie MikrocbirurgiePlastischeChirurgie,t4: 2052. McFarlandGB, HofferMM (1971).Paralysisof the intrinsicmusclesof the hand secondary to lipoma in Guyon'stunnel. Journal of Bone and Joint Surgery,53A:375-376. MilbergP, KleinertHE (1980).Giantcelltumorcompressionof the deepbranch of the ulnarnerve.Annalsof PlasticSurgery,4: 426-429. Ogino T, MinamiA, Kato H, Takahata S (1990). Ulnar nerveneuropathyat the wrist. Handchirurgie Mikrochirurgie Plastische Chirurgie, 22: 304-308. O'Hara JJ, Stone JH (1988). Ulnar neuropathy at the wrist associated with aberrant flexorcarpi ulnarisinsertion.Journal of Hand Surgery, 13A: 38~384. Papierski P (1996). Ulnar neuropathyat the wrist associated with a recurrent branchthroughthe flexorcarpiulnaristendon.Journalof HandSurgery, 21B: 347 348. Patel CB, TsaiTM, KleinertHE (1986). Hemangiomaof the mediannerve:A report of two cases.Journalof Hand Surgery,11A:76 79.
244 Rafecas JC, Daube JR, Ehmann RL (1988). Deep branch ulnar neuropathy due to giant cell tumor: Report of a case. Neurology, 38: 327-329. Rengachary SS, Arjunan K (1981). Compression of the ulnar nerve in Guyon's canal by a soft tissue giant cell tumor. Neurosurgery, 8: 400M05. Sfilgeback S (1977). Ulnar tunnel syndrome caused by anomalous muscles. Scandinavian Journal of Plastic and Reconstructive Surgery, 11: 255-258. Seddon HJ (1952). Carpal ganglion as a cause of paralysis of the deep branch of the ulnar nerve. Journal of Bone and Joint Surgery, 34B: 386 390. Strickland JW, Steichen JB (1977). Nerve tumors of the hand and forearm. Journal of Hand Surgery, 2: 2 8 5 2 9 1 . Trevaskis AE, Tilly D, Marcks KM, Heffernan A H (1967). Loss of nerve function in the hand caused by ganglions. Plastic and Reconstructive Surgery, 39:97 100. Witthaut J, Steffens K, Koob E (1994). Ungew6hnlicher Fall einer Metastase in die Weichteile der Hohlhand mit Kompression des N. medianns und N.
THE J O U R N A L OF H A N D SURGERY VOL. 23B No. 2 A P R I L 1998 ulnaris in Folge eines Nierenkarzinoms. Handchirurgie Mikrochirurgie Plastische Chirurgie, 26:137 140. Zahrawi F (1984). Acute compression ulnar neuropathy at Guyon's canal resulting from lipoma. Journal of H a n d Surgery, 9A: 238-240. Zook EG, Kucan JO, Guy RJ (1988). Palmar wrist pain caused by ulnar nerve entrapment in the flexor carpi ulnaris tendon. Journal of H a n d Surgery, 13A: 732-735.
Received: 30 May 1997 Accepted after revision: 3 November 1997 H. Koch MD, Division of Plastic Surgery,Department of Surgery,KarI-Franzens-University Graz Medical School, A-8036Graz, Austria. © 1998The British Society for Surgery of the Hand