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Combined motor and sensory median-ulnar anastomosis
3OP
Society proceedings / Electroencephalography and clinical Neurophysiology 98 (1996) 8P-4OP
Conclusions: The findings that waveforms are relatively unchanged in 2 of the 3 thumb positions and that mapping revealed a fairly uniform response goes against the hypothesis of anatomic/geometric muscle belly changes affecting what is seen by G,. In contrast, the hypothesis that positional waveform changes are principally due to change in muscle length with resultant change in muscle fiber conduction velocity would account for all the results described above. 109. The optimal site for recording sural sensory nerve action potentials. - A.V. Blando, A.W. Sable, V.M. Scruggs and J.J. Wertsch (Medical College of Wisconsin, Milwaukee, WI) Introduction: Many reported techniques for studying the sural nerve place the recording electrode posterior to the lateral malleolus. Objective: The purpose of this study was to evaluate the effect of a more proximal recording site on the amplitude of the sural sensory nerve action potential (SNAP). Methods: Bilateral sural nerves of 30 normal individuals (aged: 24-41, height 62.5”-76”) were incremently studied. Four recording sites were used: behind the lateral malleohts, and 2 cm, 4 cm, and 6 cm proximal to the lateral malleolar prominence in the groove between the distal fibula and the Achilles tendon. The sural nerve was stimulated antidromically at 10, 12, 14, 16 cm proximal to the lateral malleolus. Responses distorted by stimulus artifact were rejected. Results: One hundred percent of subjects showed increased sural amplitude with a more proximal recording site (increased 13-389%X Of the 60 extremities studied, 18 showed the largest amplitudes with G, 2 cm proximal, 22/60 at 4 cm, 20/60 at 6 cm proximal. Conclusion: This study demonstrated that a larger amplitude sural SNAP is obtained with a recording site proximal to the lateral malleolus. We postulate that a proximal recording site increases the likelihood of recording from the sural nerve prior to branching, thus giving a larger amplitude. Study supported by Medical College of Wisconsin, Department of Rehabilitation Medicine, Research Committee. A.V. Blando, Junior Member Recognition Award. 110. Comparison of reference electrode placements in sensory radial nerve studies. - F.Y. Chiou-Tan, M.J. Vennix and T. Krouskop (Baylor College of Medicine, Houston, TX) Placement of the reference recording electrode (G,) in superficial radial sensory studies has been variable. Most authors have placed it either over the 1st web space or digital branch. The standard preference is for placement of both electrodes over the nerve in sensory conductions, although not in this case. There have been no studies that have analyzed movement of Cl, with a fixed G,. Previous radial studies have changed positions of both electrodes or compared disks to rings. This study compares 3 reference electrode placements 4 cm from the fixed active electrode: (I) 1st web space, (2) index finger digital branch, and (3) separate G,s on thumb and index finger digital branches. Ten patients (7 women, 3 men) were recruited for a prospective study. Statistical analysis was performed with ANOVA and paired t tests. Results show no significant difference in the amplitude measured by these 3 techniques. Although nerve branching occurs throughout the body, only the radial sensory conduction studies this routinely. The fact that the G2 does not need to be placed over the nerve makes it unique. The sustained isoelectric field between the two branches of the digital nerve is theorized to prevent a drop in amplitude at the first web space. Study supported by NIDRR-NIH Fellowship. F.Y. Chiou-Tan, Junior Member Recognition Award. 111. Transcarpal median sensory conduction: usefulness of parametric and non-parametric methods for determining reference values. - J. De L&n and B. Masse (Lava1 University, Quebec, Que., Canada) Transcarpal median sensory nerve conduction can be performed with stimulation over the middle or index finger and recording at the midpalm
and wrist over the median nerve (Can. J. Neurol. Sci., 1988, 15: 388). The aim of the study was to improve this method by recording with surface electrodes and a standard electromyograph (Dantec Counterpoint) and determining reference values following optimal statistical analysis. Sensory nerve conduction studies were estimated in 146 healthy hands (73 volunteers from hospital staff). Ulnar and radial sensory conduction velocities were also measured. None of these conduction velocities were normally distributed. In addition, the data were distributed in discrete clusters due to the stepwise latency determination system provided by the Counterpoint. Side-to-side correlation was highly significant. There was no significant correlation with age. Height was weakly and inconsistently correlated. Correction for height and skewness did not result in a normal distribution. In the light of these results, non-parametric statistical methods may provide a more suitable approach for determining reference values in sensory nerve conduction studies.
112. Combined motor and sensory medii-ulnar anastomosis. - G.C. Claussen ‘, B.K. Ahmad b and SJ. Oh a t” University of Alabama at Birmingham, Birmingham, AL; b Henry Ford Hospital, Detroit, MU
Martin-Gmber anastomosis (median-ulnar motor nerve anastomosis; MGAJ is the most common form of anomalous innervation. A sensory median-ulnar anastomosis with MGA is rarely seen and has been reported only in one other case of which we are aware. We are reporting a case in which the digit V sensory nerve stimulation recorded a 20 PV compound nerve action potential (CNAP) in the ulnar nerve at wrist and 7.5 PV CNAP in the median nerve at elbow, and the ulnar wrist mixed nerve stimulation recorded a 20 PV CNAP in the median nerve at elbow. ‘these findings are indicative of a sensory median-ulnar nerve fiber crossing. Findings typical of median-ulnar motor anastomosis were also noted, including the compound muscle action potential (CMAP) recording from the first dorsal interosseous (FDI), abductor digiti quinti (ADQ), and abductor pollicis brevis (APB) muscles were larger with stimulation of median nerve at the elbow compared to the wrist, and the CMAP was larger with ulnar wrist stimulation as compared to the elbow recording over the PDI and APB muscles. This case, therefore, represents a case of median-ulnar motor and sensory fiber anastomosis.
113. Double anastomosis of medii-ulnar and ulnar-median nerves. - S.J. Oh *, G.C. Claussen a and B.K. Ahmad b (’ University of Alabama at Birmingham, Birmingham, AL; b Henry Ford Hospital, Detroit, MU
We are reporting the first case of double median-ulnar and ulnarmedian nerve anastomosis on the basis of an electrophysiological study. Nerve conduction studies performed in a 75year-old white female patient with a previous history of brachial plexus neuropathy showed a remarkable difference (7.5 mV) in the compound muscle action potential (CMAP) amplitude between wrist and elbow stimulation of the ulnar nerve. A systematic work-up was performed to determine whether this difference was due to a Martin-Gruber anastomosis (MGA). Electrophysiological findings in our case met all criteria for MGA in the abductor digiti quinti (ADQ) and first dorsal interosseous (PDI) muscles, with predominantly anomalous nerve tibers innervating these muscles. In addition, there was a shift of the initial deflection of the CMAPs from “positive” to “negative” in the abductor pollicis brevis muscle between ulnar-wrist and elbow stimulations. This shift is indicative of an ulnar-median crossing of motor fibers. A previous anatomical study described a variant of MGA which may represent the basis for the double crossing of motor fibers in our case.
Society proceedings / Electroencephalography and clinical Neurophysiology 98 (1996) 8P-4OP
Conclusions: The findings that waveforms are relatively unchanged in 2 of the 3 thumb positions and that mapping revealed a fairly uniform response goes against the hypothesis of anatomic/geometric muscle belly changes affecting what is seen by G,. In contrast, the hypothesis that positional waveform changes are principally due to change in muscle length with resultant change in muscle fiber conduction velocity would account for all the results described above. 109. The optimal site for recording sural sensory nerve action potentials. - A.V. Blando, A.W. Sable, V.M. Scruggs and J.J. Wertsch (Medical College of Wisconsin, Milwaukee, WI) Introduction: Many reported techniques for studying the sural nerve place the recording electrode posterior to the lateral malleolus. Objective: The purpose of this study was to evaluate the effect of a more proximal recording site on the amplitude of the sural sensory nerve action potential (SNAP). Methods: Bilateral sural nerves of 30 normal individuals (aged: 24-41, height 62.5”-76”) were incremently studied. Four recording sites were used: behind the lateral malleohts, and 2 cm, 4 cm, and 6 cm proximal to the lateral malleolar prominence in the groove between the distal fibula and the Achilles tendon. The sural nerve was stimulated antidromically at 10, 12, 14, 16 cm proximal to the lateral malleolus. Responses distorted by stimulus artifact were rejected. Results: One hundred percent of subjects showed increased sural amplitude with a more proximal recording site (increased 13-389%X Of the 60 extremities studied, 18 showed the largest amplitudes with G, 2 cm proximal, 22/60 at 4 cm, 20/60 at 6 cm proximal. Conclusion: This study demonstrated that a larger amplitude sural SNAP is obtained with a recording site proximal to the lateral malleolus. We postulate that a proximal recording site increases the likelihood of recording from the sural nerve prior to branching, thus giving a larger amplitude. Study supported by Medical College of Wisconsin, Department of Rehabilitation Medicine, Research Committee. A.V. Blando, Junior Member Recognition Award. 110. Comparison of reference electrode placements in sensory radial nerve studies. - F.Y. Chiou-Tan, M.J. Vennix and T. Krouskop (Baylor College of Medicine, Houston, TX) Placement of the reference recording electrode (G,) in superficial radial sensory studies has been variable. Most authors have placed it either over the 1st web space or digital branch. The standard preference is for placement of both electrodes over the nerve in sensory conductions, although not in this case. There have been no studies that have analyzed movement of Cl, with a fixed G,. Previous radial studies have changed positions of both electrodes or compared disks to rings. This study compares 3 reference electrode placements 4 cm from the fixed active electrode: (I) 1st web space, (2) index finger digital branch, and (3) separate G,s on thumb and index finger digital branches. Ten patients (7 women, 3 men) were recruited for a prospective study. Statistical analysis was performed with ANOVA and paired t tests. Results show no significant difference in the amplitude measured by these 3 techniques. Although nerve branching occurs throughout the body, only the radial sensory conduction studies this routinely. The fact that the G2 does not need to be placed over the nerve makes it unique. The sustained isoelectric field between the two branches of the digital nerve is theorized to prevent a drop in amplitude at the first web space. Study supported by NIDRR-NIH Fellowship. F.Y. Chiou-Tan, Junior Member Recognition Award. 111. Transcarpal median sensory conduction: usefulness of parametric and non-parametric methods for determining reference values. - J. De L&n and B. Masse (Lava1 University, Quebec, Que., Canada) Transcarpal median sensory nerve conduction can be performed with stimulation over the middle or index finger and recording at the midpalm
and wrist over the median nerve (Can. J. Neurol. Sci., 1988, 15: 388). The aim of the study was to improve this method by recording with surface electrodes and a standard electromyograph (Dantec Counterpoint) and determining reference values following optimal statistical analysis. Sensory nerve conduction studies were estimated in 146 healthy hands (73 volunteers from hospital staff). Ulnar and radial sensory conduction velocities were also measured. None of these conduction velocities were normally distributed. In addition, the data were distributed in discrete clusters due to the stepwise latency determination system provided by the Counterpoint. Side-to-side correlation was highly significant. There was no significant correlation with age. Height was weakly and inconsistently correlated. Correction for height and skewness did not result in a normal distribution. In the light of these results, non-parametric statistical methods may provide a more suitable approach for determining reference values in sensory nerve conduction studies.
112. Combined motor and sensory medii-ulnar anastomosis. - G.C. Claussen ‘, B.K. Ahmad b and SJ. Oh a t” University of Alabama at Birmingham, Birmingham, AL; b Henry Ford Hospital, Detroit, MU
Martin-Gmber anastomosis (median-ulnar motor nerve anastomosis; MGAJ is the most common form of anomalous innervation. A sensory median-ulnar anastomosis with MGA is rarely seen and has been reported only in one other case of which we are aware. We are reporting a case in which the digit V sensory nerve stimulation recorded a 20 PV compound nerve action potential (CNAP) in the ulnar nerve at wrist and 7.5 PV CNAP in the median nerve at elbow, and the ulnar wrist mixed nerve stimulation recorded a 20 PV CNAP in the median nerve at elbow. ‘these findings are indicative of a sensory median-ulnar nerve fiber crossing. Findings typical of median-ulnar motor anastomosis were also noted, including the compound muscle action potential (CMAP) recording from the first dorsal interosseous (FDI), abductor digiti quinti (ADQ), and abductor pollicis brevis (APB) muscles were larger with stimulation of median nerve at the elbow compared to the wrist, and the CMAP was larger with ulnar wrist stimulation as compared to the elbow recording over the PDI and APB muscles. This case, therefore, represents a case of median-ulnar motor and sensory fiber anastomosis.
113. Double anastomosis of medii-ulnar and ulnar-median nerves. - S.J. Oh *, G.C. Claussen a and B.K. Ahmad b (’ University of Alabama at Birmingham, Birmingham, AL; b Henry Ford Hospital, Detroit, MU
We are reporting the first case of double median-ulnar and ulnarmedian nerve anastomosis on the basis of an electrophysiological study. Nerve conduction studies performed in a 75year-old white female patient with a previous history of brachial plexus neuropathy showed a remarkable difference (7.5 mV) in the compound muscle action potential (CMAP) amplitude between wrist and elbow stimulation of the ulnar nerve. A systematic work-up was performed to determine whether this difference was due to a Martin-Gruber anastomosis (MGA). Electrophysiological findings in our case met all criteria for MGA in the abductor digiti quinti (ADQ) and first dorsal interosseous (PDI) muscles, with predominantly anomalous nerve tibers innervating these muscles. In addition, there was a shift of the initial deflection of the CMAPs from “positive” to “negative” in the abductor pollicis brevis muscle between ulnar-wrist and elbow stimulations. This shift is indicative of an ulnar-median crossing of motor fibers. A previous anatomical study described a variant of MGA which may represent the basis for the double crossing of motor fibers in our case.