Orthodromic transposition of the temporal muscle for facial paralysis: Made easy and better

The authors present a modified technique of transposition of temporal muscle for reanimation of facial paralysis. Fourteen cases illustrate the simplicity, advantages, and excellent esthetic and functional results of this method.

Facial Reanimation Utilizing Combined Orthodromic Temporalis Muscle Flap and End-to-Side Cross-Face Nerve Grafts

Individuals with facial paralysis of 6 months or more without evidence of clinical or electromyographic improvement have been successfully reanimated utilizing an orthodromic temporalis transfer in conjunction with end-to-side cross-face nerve grafts. The temporalis muscle insertion is released from the coronoid process of the mandible and sutured to a fascia lata graft that is secured distally to the commissure and paralyzed hemilip. The orthodromic transfer of the temporalis muscle overcomes the concave temporal deformity and zygomatic fullness produced by the turning down of the central third of the muscle (Gillies procedure) while yielding stronger muscle contraction and a more symmetric smile. The muscle flap is combined with cross-face sural nerve grafts utilizing end-to-side neurorrhaphies to import myelinated motor fibers to the paralyzed muscles of facial expression in the midface and perioral region. Cross-face nerve grafting provides the potential for true spontaneous facial motion. We feel that the synergy created by the combination of techniques can perhaps produce a more symmetrical and synchronized smile than either procedure in isolation.Nineteen patients underwent an orthodromic temporalis muscle flap in conjunction with cross-face (buccal-buccal with end-to-side neurorrhaphy) nerve grafts. To evaluate the symmetry of the smile, we measured the length of the two hemilips (normal and affected) using the CorelDRAW X3 software. Measurements were obtained in the pre- and postoperative period and compared for symmetry.There was significant improvement in smile symmetry in 89.5 % of patients.Orthodromic temporalis muscle transfer in conjunction with cross face nerve grafts creates a synergistic effect frequently producing an aesthetic, symmetric smile.This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors at www.spinger.com/00266.

Division of labor in frontal eye field neurons during presaccadic remapping of visual receptive fields.

Our percept of visual stability across saccadic eye movements may be mediated by presaccadic remapping. Just before a saccade, neurons that remap become visually responsive at a future field (FF), which anticipates the saccade vector. Hence, the neurons use corollary discharge of saccades. Many of the neurons also decrease their response at the receptive field (RF). Presaccadic remapping occurs in several brain areas including the frontal eye field (FEF), which receives corollary discharge of saccades in its layer IV from a collicular-thalamic pathway. We studied, at two levels, the microcircuitry of remapping in the FEF. At the laminar level, we compared remapping between layers IV and V. At the cellular level, we compared remapping between different neuron types of layer IV. In the FEF in four monkeys (Macaca mulatta), we identified 27 layer IV neurons with orthodromic stimulation and 57 layer V neurons with antidromic stimulation from the superior colliculus. With the use of established criteria, we classified the layer IV neurons as putative excitatory (n = 11), putative inhibitory (n = 12), or ambiguous (n = 4). We found that just before a saccade, putative excitatory neurons increased their visual response at the RF, putative inhibitory neurons showed no change, and ambiguous neurons increased their visual response at the FF. None of the neurons showed presaccadic visual changes at both RF and FF. In contrast, neurons in layer V showed full remapping (at both the RF and FF). Our data suggest that elemental signals for remapping are distributed across neuron types in early cortical processing and combined in later stages of cortical microcircuitry.

Pedro Nunes e a distinção de dois tipos de trajetórias na navegação: a linha de rumo e o círculo máximo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Gap junction channels and cardiac impulse propagation

The role of gap junction channels on cardiac impulse propagation is complex. This review focuses on the differential expression of connexins in the heart and the biophysical properties of gap junction channels under normal and disease conditions. Structural determinants of impulse propagation have been gained from biochemical and immunocytochemical studies performed on tissue extracts and intact cardiac tissue. These have defined the distinctive connexin coexpression patterns and relative levels in different cardiac tissues. Functional determinants of impulse propagation have emerged from electrophysiological experiments carried out on cell pairs. The static properties (channel number and conductance) limit the current flow between adjacent cardiomyocytes and thus set the basic conduction velocity. The dynamic properties (voltage-sensitive gating and kinetics of channels) are responsible for a modulation of the conduction velocity during propagated action potentials. The effect is moderate and depends on the type of Cx and channel. For homomeric-homotypic channels, the influence is small to medium; for homomeric-heterotypic channels, it is medium to strong. Since no data are currently available on heteromeric channels, their influence on impulse propagation is speculative. The modulation by gap junction channels is most prominent in tissues at the boundaries between cardiac tissues such as sinoatrial node-atrial muscle, atrioventricular node-His bundle, His bundle-bundle branch and Purkinje fibers-ventricular muscle. The data predict facilitation of orthodromic propagation.

Ultrasound-guided needle positioning in sensory nerve conduction study of the sural nerve

OBJECTIVES: To evaluate the usefulness of ultrasound imaging to improve the positioning of the recording needle for nerve conduction studies (NCS) of the sural nerve. METHODS: Orthodromic NCS of the sural nerve was performed in 44 consecutive patients evaluated for polyneuropathy. Ultrasound-guided needle positioning (USNP) was compared to conventional "blind" needle positioning (BNP), electrically guided needle positioning (EGNP), and to recordings with surface electrodes (SFN). RESULTS: The mean distance between the needle tip and the nerve was 1.1 mm with USNP compared to 5.1 mm with BNP (p<0.0001). The mean amplitude of the sensory nerve action potential (SNAP) was 21 microV with USNP and 11 microV with BNP (p<0.0001). Compared to BNP, nerve-needle distances and SNAP amplitudes did not improve with EGNP. SNAP amplitudes recorded with SFN were significantly smaller than with BNP, EGNP and USNP. CONCLUSION: Ultrasound increases the precision of needle positioning markedly, compared to conventional methods. The amplitude of the recorded SNAP is usually clearly greater using USNP. In addition, USNP is faster, less painful and less dependent on the patient. SIGNIFICANCE: USNP is superior to BNP, EGNP, and SFN in accurate measurement of SNAP amplitude. It has a potential use in the routine near-nerve needle sensory NCS of pure sensory nerves.

Sural nerve conduction studies using ultrasound-guided needle positioning: Influence of age and recording location.

INTRODUCTION The aim of this study was to compare orthodromic sural nerve conduction study (NCS) results using ultrasound-guided needle positioning (USNP) to surface electrode recordings. METHODS 51 healthy subjects aged 24 - 80 years, divided into 5 age groups, were examined. Electrical stimuli were applied behind the lateral malleolus. Sensory nerve action potentials (SNAPs) were recorded 8 and 15 cm proximally with surface and needle electrodes. RESULTS Mean SNAP amplitudes in µV (surface/needle electrodes) averaged 12.7 (SD 7.6)/40.6 (SD 20.8), P<0.001, for subjects aged 20-29 years, and 5.0 (SD 2.4)/19.8 (SD 9.8), P<0.01, for subjects aged > 60 years. SNAP amplitudes were smaller at the proximal recording location. DISCUSSION NCS using USNP yield higher amplitude responses than surface electrodes in all age groups at all recording sites. SNAP amplitudes are smaller at proximal recording locations due to sural nerve branching. This article is protected by copyright. All rights reserved.