Ulnar variance and Shea type II ulnar injury

16P

Society proceedings / Electroencephalography

side of the third finger and radial side of the fourth finger. The hypothesis was whether the following nerve conduction techniques designed would enhance diagnosis of digital nerve injury: (1) standard ring electrodes, (2) ring electrode response from two adjacent fingers. and (3) disk electrodes placed between two fmgers. In this prospective, intrinsically controlled study, a 2% lidocaine digital nerve block was performed on 10 normal subjects (7 women, 3 men) who underwent pre- and post-injection sensory conduction studies. Initial anthropomorphic measurements were recorded, and temperature was maintained > 30°C. Statistical analysis was performed with a 2-tailed, paired t test. Results show a decrease in amplitude of 94% for rings on the 4th digit, 62% for the 3rd digit, 77% for disk electrodes between the 4th and 3rd digits, and 74% for rings on two fingers (P < 0.005). with no significant change in peak latency (P > 0.3). In conclusion, all techniques used yielded a significant change in amplitude, though rings on the 4th digit were the greatest and on the 3rd the least. It is hoped this study will aid the electromyographer in postoperative diagnosis. Study supported by NIDER-NIH Fellowship. 40. Nerve conduction studies in median nerve lipofibromas. - J.J. Wertsch, W.W. Dzwierzynski and A.V. Bland0 (Medical College of Wisconsin, Milwaukee, WI) Over 70 cases of median nerve lipotibroma are reported, but little is noted regarding nerve conduction. We report 2 cases of median nerve lipotibromatous hamartoma. A 27-year-old patient with 1 year of progressive left hand numbness was initially diagnosed flexor tendinitis and early carpal tunnel syndrome (CTS). Electrodiagnostic consultation was requested when conservative therapy offered no help. Median sensory responses were prolonged and small for all digits (index 5.3 msec, 12 PV at 14 cm), median motor 5.4 msec, 7 mV. A ropey wrist structure was noted with wrist flexion. ulnar deviation and firm resistance to fmger Bexion. Magnetic resonance imaging (MRI) revealed a 10 cm segment grossly enlarged median nerve with individual fascicles outlined: diagnosis lipotibroma. Simple carpal tunnel release gave symptomatic relief with improvement of serial postoperative nerve conduction studies. The second case also presented with right CTS symptoms and wrist fullness. Right median studies revealed absent sensory responses and motor 10.0 msec, 6 mV. MRI revealed a 6 cm segment of grossly enlarged median nerve. Carpal tunnel release is planned. It is important to realize that the wrist mass is the median nerve itself and that the symptoms can be relieved with unroofing the carpal tunnel to avoid the prior surgical tendency to remove “the mass” to relieve the CTS symptoms. 41. Ulnar variance and Shea type II ulnar nerve injury. - A.V. Bland0 and J.J. Wertsch (Medical College of Wisconsin, Milwaukee, WI) A 4l-year-old gentleman was referred for electrodiagnostic consultation regarding left hand weakness and numbness which he developed after a minor twisting wrist injury. Physical examination revealed marked ulnar intrinsic atrophy with no sensory loss. Normal nerve conduction studies were obtained for median sensory, median motor, and ulnar sensory studies (dorsal ulnar cutaneous, and ring and little finger digital ulnar sensory nerve responses). Ulnar motor studies were markedly abnormal with hypothenar recording response 830 pV, 4. I msec and first dorsal interosseous manus recording unobtainable. EMG showed denervation of all ulnar innervated muscles distal to the wrist with all median innervated and proximal muscles normal. It was hard to understand how such a severe focal nerve injury could result from a minor wrist injury until a left wrist roentgenogram was obtained showing 9 mm positive ulna variance with dorsal subluxation of the distal ulna which was a residual from a childhood injury. The biomechanical effect of bony deformities are important to consider in analyzing the etiology of nerve injuries. This case reports a

and

clinical Neurophysiology

98 (1996) 8P-40P

significant Shea type II Guyon canal ulnar nerve injury after a minor twisting wrist injury in a patient with longstanding distal positive ulnar variance with ulna dorsal subluxation. 42. High-dose intravenous immunoglobulin in polymyositis: our clinical experience. - C.T. Cancela, G. Alfonso and J.R. Carlo (University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico) Polymyositis is an inflammatory muscle disease of unknown etiology. An autoimmune mechanism has been suggested. Corticosteroids have been the main therapeutic modality used. Others include immunosuppressive drugs, plasmapheresis, and total body irradiation. Cases occur where these are not effective or serious side effects outweigh benefits. Immunomodulatory treatment with intravenous immunoglobulin (IVIg) has been useful in several diseases with altered immunoregulation. It has been proved effective in refractory cases of dermatomyositis. We treated 5 chronic refractory cases of polymyositis, with muscle biopsy confirmed diagnosis. Electrodiagnostic studies showed active disease with positive waves, fibrillations, and polyphasic motor unit potentials. All patients were receiving prednisone. We administered IVIg, 400 mg/kg/day for 5 days without adverse reactions, in an uncontrolled trial, in a setting where plasmapheresis was not available. Results were favorable. All patients showed marked improvement in muscle strength by manual muscle testing, improving ambulation and daily living activities. Therapeutic response lasted a mean of 6 weeks. These findings open the possibility that IVlg may be a therapeutic alternative to chronic refractory polymyositis. Further research is needed to assess optimal therapeutic dosage of IVlg or the use of this modality in early stages of the condition. 43. Pregnancy associated myotonia. - J.T. Gonzalez, MJ. Giuliani, G. Feeru and E.P. Hoffman (University of Pittsburgh, Pittsburgh, PA) Introductionand objective: Exacerbationof myotonia associated with increased weakness during pregnancy has been described in several myotonic disorders. Case reports and results: We report 3 cases where women in the first 18 weeks of pregnancy present with weakness and muscle stiffness. Creatine kinase was normal and cataracts were absent on slit lamp examination. Myotonic potentials were present on electromyography in several muscles. Genetic testing for myotonic dystrophy and the two mutations causing hyperkalemic paralysis were negative. One of the patients has relatives who demonstrate clinical or electrical myotonia. For this patient, linkage analysis is in progress for skeletal muscle sodium, chloride, and calcium channel genes. The rest of the pregnancy, labor and delivery were normal. A few months after delivery, there was no evidence of weakness or muscle stiffness in two of the patients. The other patient had dramatic clinical improvement. Repeat electromyography showed a decrease (I patient, with family history) or resolution of electrical myotonia (2 patients). Conclusion: The clinical course and genetic testing demonstrate that these patients do not correspond to the typical myotonic syndromes. Whether this phenotype represents a homogenous genetic disorder is unknown but the recognition, management and prognostic issues associated with this new group of patients are important. J.T. Gonzalez, Junior Member Recognition Award. 44. Oculopharyngeal muscular dystrophy: pedigrees unrelated to French Canada. - G.B. Creel *, MJ. Giulkmi ‘, B. Brais b and G. Rouleau b (” University of Pittsburgh, Pittsburgh, PA; b McGill University, Montreal, QC, Canada) Oculopharyngealmuscular dystrophy (OPMD) is an adult onset muscular dystrophy with initial symptoms in the 5th to 7th decades. Ptosis