Ipsilateral Muscle Research Articles

Cortical Effects on Ipsilateral Hindlimb Muscles Revealed with Stimulus-Triggered Averaging of EMG Activity.

While a large body of evidence supports the view that ipsilateral motor cortex may make an important contribution to normal movements and to recovery of function following cortical injury (Chollet et al. 1991; Fisher 1992; Caramia et al. 2000; Feydy et al. 2002), relatively little is known about the properties of output from motor cortex to ipsilateral muscles. Our aim in this study was to characterize the organization of output effects on hindlimb muscles from ipsilateral motor cortex using stimulus-triggered averaging of EMG activity. Stimulus-triggered averages of EMG activity were computed from microstimuli applied at 60-120 μA to sites in both contralateral and ipsilateral M1 of macaque monkeys during the performance of a hindlimb push-pull task. Although the poststimulus effects (PStEs) from ipsilateral M1 were fewer in number and substantially weaker, clear and consistent effects were obtained at an intensity of 120 μA. The mean onset latency of ipsilateral poststimulus facilitation was longer than contralateral effects by an average of 0.7 ms. However, the shortest latency effects in ipsilateral muscles were as short as the shortest latency effects in the corresponding contralateral muscles suggesting a minimal synaptic linkage that is equally direct in both cases.

Bone conducted vibration to the mastoid produces horizontal, vertical and torsional eye movements.

We have previously shown that bone-conducted vibration to each mastoid in humans results in small stimulus-locked horizontal and vertical eye movements suggesting that the ipsilateral superior oblique and the contralateral inferior rectus are activated. However, as torsional responses were not measured we have repeated the study by measuring torsional as well as horizontal and vertical responses in seven adult subjects during different directions of gaze. We measured stimulus-locked horizontal (H), vertical (V) and torsional (T) eye movements during brief stimulation to the mastoid unilaterally and bilaterally using a high-speed, high-resolution video technique. Bone-conducted vibrations were delivered to each mastoid separately as well as bilaterally using a Radioear B71 bone oscillator while the subjects viewed targets 2 metres away situated straight ahead and 10° to the right and left. For unilateral stimulation the eyes moved downwards when directed away from the stimulated mastoid, along with bilateral counter-rolling away from the side of stimulation. Horizontal movements were small, with little effect of gaze position. Bilateral stimulation enhanced the downward responses. Bone conducted vibration to the mastoid in humans produces vertical and torsional eye movements consistent with activation of the ipsilateral superior oblique muscle, and the contralateral inferior oblique muscle to produce counter rolling of the eyes away from the stimulated mastoid.

Adaptability of the Immature Ocular Motor Control System: Unilateral IGF-1 Medial Rectus Treatment.

Unilateral treatment with sustained release IGF-1 to one medial rectus muscle in infant monkeys was performed to test the hypothesis that strabismus would develop as a result of changes in extraocular muscles during the critical period of development of binocularity. Sustained release IGF-1 pellets were implanted unilaterally on one medial rectus muscle in normal infant monkeys during the first 2 weeks of life. Eye position was monitored using standard photographic methods. After 3 months of treatment, myofiber and neuromuscular size, myosin composition, and innervation density were quantified in all rectus muscles and compared to those in age-matched controls. Sustained unilateral IGF-1 treatments resulted in strabismus for all treated subjects; 3 of the 4 subjects had a clinically significant strabismus of more than 10°. Both the treated medial rectus and the untreated ipsilateral antagonist lateral rectus muscles had significantly larger myofibers. No adaptation in myofiber size occurred in the contralateral functionally yoked lateral rectus or in myosin composition, neuromuscular junction size, or nerve density. Sustained unilateral IGF-1 treatment to extraocular muscles during the sensitive period of development of orthotropic eye alignment and binocularity was sufficient to disturb ocular motor development, resulting in strabismus in infant monkeys. This could be due to altering fusion of gaze during the early sensitive period. Serial measurements of eye alignment suggested the IGF-1-treated infants received insufficient coordinated binocular experience, preventing the establishment of normal eye alignment. Our results uniquely suggest that abnormal signaling by the extraocular muscles may be a cause of strabismus.

Autologous Reconstruction of a Complex Form of Poland Syndrome Using 2 Abdominal Perforator Free Flaps

Poland syndrome is the most frequent cause of congenital breast aplasia and hypoplasia. Breast and possible chest wall deformities can be treated with several surgical techniques, including implants, and pedicled or free flaps.We describe the case of a young patient with severe Poland syndrome with amastia, athelia, and deformity of the chest wall, and aplasia of 2 ribs. Marked hypoplasia of the ipsilateral latissimus dorsi muscle ruled out a reliable reconstructive option.Two perforator flaps were performed in a single-stage operation. A hemi-deep inferior epigastric perforator flap was harvested to correct the chest deformity, whereas the contralateral superficial inferior epigastric artery flap allowed breast reconstruction.No complications occurred and a subjectively and objectively pleasing cosmetic result was maintained at 3-year follow-up.

Abstract 403: E-selectin Transfer by Recombinant Adeno-associated Virus Improves Angiogenesis in a Murine Model of Hindlimb Ischemia

Novel cell-based therapies, including optimization of the wound microenvironment via chemical or genetic means, hold promise to revolutionize the treatment of chronic limb ischemia and ischemic wounds. We examined the hypothesis that increasing expression in ischemic tissue of the endothelial adhesion molecule E-selectin by adeno-associated viral transduction would promote angiogenesis in a murine model of hindlimb ischemia. 12-week-old female C57BL/6 mice (N=10) underwent unilateral femoral artery ligation. After ligation, each mouse was injected in the ipsilateral semimebranosus muscle with 1x108 viral particles of either adeno-associated virus recombinant with human E-selectin gene (AAV/E-selectin) or adeno-associated virus recombinant with green fluorescent protein gene as control (AAV/GFP) suspended in phosphate-buffered saline (N=5/group). Ischemia was confirmed by laser Doppler perfusion imaging on post-ligation day one. Mice were sacrificed on post-ligation day seven and semimembranosus muscle harvested from the ligated limb. Muscle was fixed, embedded, and sectioned in 5 μm intervals. To assess the efficacy of viral transduction, we performed immunohistochemistry (IHC) of each section from the AAV/GFP group with anti-GFP antibody and from the AAV/E-selectin group with anti-human E-selectin antibody. Angiogenesis was evaluated by capillary density with IHC of all slides for endothelial cell marker VEGFR2 with anti-VEGFR2 antibody. Relative fluorescence index per high-powered field (RFI) was recorded for each slide. E-selectin RFI was 4 times greater, VEGFR2 RFI was 2 times greater, and E-selectin/VEGFR2 RFI ratio was 2 times greater in AAV/E-selectin treated tissue than in control. In conclusion, this study demonstrates the AAV/E-selectin vector as an effective means to upregulate E-selectin expression in ischemic muscle and supports E-selectin upregulation as a possible means to improve ischemia-induced angiogenesis.

Single-Point but Not Tonic Cuff Pressure Pain Sensitivity Is Associated with Level of Physical Fitness – A Study of Non-Athletic Healthy Subjects

Exercise is often used for pain rehabilitation but the link between physical activity level and pain sensitivity is still not fully understood. Pressure pain sensitivity to cuff algometry and conditioned pain modulation (CPM) were evaluated in highly active men (n=22), normally active men (n=26), highly active women (n=27) and normally active women (n=23) based on the Godin Leisure-Time Exercise Questionnaire. Cuff pressure pain sensitivity was assessed at the arm and lower leg. The subjects scored the pain intensity on an electronic Visual Analogue Scale (VAS) during ten minutes with 25 kPa constant cuff pressure and two minutes with zero pressure. The maximal VAS score and area under the VAS-curve were extracted. Pressure pain thresholds (PPT) were recorded by manual pressure algometry on the ipsilateral tibialis anterior muscle before, during and after the tonic arm stimulation. Tonic cuff stimulation of the arm and leg resulted in higher VAS peak scores in women compared with men (p<0.04). In all groups the PPTs were reduced during and after the cuff stimulation compared with baseline (p=0.001). PPT were higher in men compared with women (p=0.03) and higher in highly physical active compared with normal active (p=0.048). Besides the well-known gender difference in pressure pain sensitivity this study demonstrates that a high physical fitness degree in non-athletic subjects is associated with increased pressure pain thresholds but does not affect cuff pressure pain sensitivity in healthy people.

Dose-volume factors correlating with trismus following chemoradiation for head and neck cancer

Background. To investigate the dose-volume factors in mastication muscles that are implicated as possible causes of trismus in patients following treatment with intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy for head and neck cancers.Material and methods. All evaluable patients treated at our institution between January 2004 and April 2009 with chemotherapy and IMRT for squamous cell cancers of the oropharynx, nasopharynx, hypopharynx or larynx were included in this analysis (N = 421). Trismus was assessed using CTCAE 4.0. Bi-lateral masseter, temporalis, lateral pterygoid and medial pterygoid muscles were delineated on axial computed tomography (CT) treatment planning images, and dose-volume parameters were extracted to investigate univariate and multimetric correlations.Results. Forty-six patients (10.9%) were observed to have chronic trismus of grade 1 or greater. From analysis of baseline patient characteristics, toxicity correlated with primary site and patient age. From dose-volume analysis, the steepest dose thresholds and highest correlations were seen for mean dose to ipsilateral masseter (Spearman's rank correlation coefficient Rs = 0.25) and medial pterygoid (Rs = 0.23) muscles. Lyman-Kutcher-Burman modeling showed highest correlations for the same muscles. The best correlation for multimetric logistic regression modeling was withV68Gy to the ipsilateral medial pterygoid (Rs = 0.29).Conclusion. Chemoradiation-induced trismus remains a problem particularly for patients with oropharyngeal carcinoma. Strong dose-volume correlations support the hypothesis that limiting dose to the ipsilateral masseter muscle and, in particular, the medial pterygoid muscle may reduce the likelihood of trismus.

Does electrocautery damage cochlear implants?

1) Evaluate the effects of monopolar cautery on cochlear implant devices. 2) Determine whether voltage fluctuations within the cochlear implant adversely affect the cochlear implant devices Two Med-El cochlear implants modified to record voltage difference from the apical and proximal electrodes were implanted into an unembalmed, fresh cadaver. Cautery was applied to the ipsilateral pectoralis major muscle and ipsilateral temporalis muscle at bipolar, monopolar coagulation, and monopolar cut settings of 50 W. The intensity in each modality setting was increased by increments of 10 W to a maximum of 100 W. Integrity testing was performed before, during, and after each cautery setting. Voltage fluctuations were measured during cautery, and maximal voltage changes for each setting were noted. After explantation, devices were returned to the manufacturer for in-depth failure analysis to evaluate for any damage to the devices. Tertiary medical center. Cadaveric study. Basic science laboratory. No change in impedance or integrity testing occurred at any cautery setting when applied to either to pectoralis major or temporalis. The maximum voltage change was 22 V. Comprehensive device analysis showed no evidence of device damage from the study. The cochlear implant devices had no evidence of electrical damage by monopolar cautery, even up to levels of 100 W in the temporalis muscle. The maximum voltage change was 22 V, likely resulting from protecting diodes within the implant. Additional study is necessary, but more flexible recommendations regarding electrosurgery in cochlear implant recipients should be considered.

Mesenchymal Stem Cell Survival after Intraspinal Transplantation

Following spinal cord hemisection at C2 (SH), removal of descending excitatory drive to phrenic motoneurons results in ipsilateral diaphragm muscle paralysis with partial spontaneous recovery of rhythmic phrenic activity over time. Brain‐derived neurotrophic factor (BDNF) plays an important role in neuroplasticity following SH. Intraspinal transplantation of mesenchymal stem cells engineered to produce BDNF‐GFP (BDNF‐MSCs) at the time of injury promotes functional recovery of all animals, despite low levels of MSC survival at 14 days post‐SH. The goal of the present study was to determine the survival and localization of BDNF‐MSCs after intraspinal transplantation. BDNF‐MSCs were injected intraspinally at C4 (2 sites, total 2 x 105 cells in 4 µl) in adult male Sprague‐Dawley rats. After one and three days, the cervical spinal cord was fixed, excised, and cut longitudinally. Survival of transplanted BDNF‐MSCs was confirmed in all animals at 1 day post‐transplantation (n=5) and in five of 6 animals at 3 days post‐transplantation. BDNF‐MSCs remained localized at the site of injection in the white matter at 1 and 3 days, with an average volume of 1.1 ± 0.3 µl. There was no localization of MSCs in the vicinity of phrenic motoneurons identified by retrograde labeling with cholera toxin subunit B. Understanding the time course of stem cell survival after transplantation is important in defining windows of opportunity during which the beneficial effects of BDNF on respiratory function after spinal cord injury are executed.Supported by HL96750 and Mayo Clinic Center for Regenerative Medicine.

Transcranial direct current stimulation improves ipsilateral selective muscle activation in a frequency dependent manner.

Failure to suppress antagonist muscles can lead to movement dysfunction, such as the abnormal muscle synergies often seen in the upper limb after stroke. A neurophysiological surrogate of upper limb synergies, the selectivity ratio (SR), can be determined from the ratio of biceps brachii (BB) motor evoked potentials to transcranial magnetic stimulation prior to forearm pronation versus elbow flexion. Surprisingly, cathodal transcranial direct current stimulation (c-TDCS) over ipsilateral primary motor cortex (M1) reduces (i.e. improves) the SR in healthy adults, and chronic stroke patients. The ability to suppress antagonist muscles may be exacerbated at high movement rates. The aim of the present study was to investigate whether the selective muscle activation of the biceps brachii (BB) is dependent on altering frequency demands, and whether the c-tDCS improvement of SR is dependent on task frequency. Seventeen healthy participants performed repetitive isometric elbow flexion and forearm pronation at three rates, before and after c-tDCS or sham delivered to ipsilateral left M1. Ipsilateral c-tDCS improved the SR in a frequency dependent manner by selectively suppressing BB antagonist excitability. Our findings confirm that c-tDCS is an effective tool for improving selective muscle activation, and provide novel evidence for its efficacy at rates of movement where it is most likely to benefit task performance.

The impact of theta burst stimulation over supplementary motor cortex on gait perturbations of Parkinson’s diseases patients with and without freezing of gait

Transcranial magnetic stimulation (TMS) has the potential to modify cortical excitability as a therapy for neurological and psychiatric disease. Limitations include the transient and localised nature of the effects. In some situations, where cortical excitability is diffusely abnormal, more widespread modulation of cortical activity is desirable. The cerebellum has extensive connections to cortical areas, via the dentato-thalamo-cortical pathway, and the cerebellum is therefore a promising stimulation site for treating conditions with altered cortical excitability. Previous studies have shown that 50 Hz intermittent theta burst stimulation (iTBS) of the cerebellum increases the amplitude of motor evoked potentials (MEP) obtained from ipsilateral muscles by stimulation of the contralateral motor cortex, while continuous TBS (cTBS) has the opposite effect. In this combined TMS-electroencephalography study, the effects of 30 Hz right cerebellar hemisphere TBS on TMSevoked potentials (TEP) were investigated; in particular the effects on the N100 component, which is thought to reflect intra-cortical inhibition. 16 participants, aged 18-30 years, received 30 Hz iTBS, cTBS or sham TBS with a placebo coil in three separate sessions. MEP and TEP were recorded before and after treatment. Treatment with iTBS resulted in an increase in the amplitude of the N100 compared to sham, without significantly altering MEP amplitudes. cTBS did not significantly modify N100 amplitude and had varying effects on MEP, depending on stimulus intensity. The N100 changes were present diffusely and bilaterally. The findings suggest that 30 Hz cerebellar iTBS enhances activity in both inhibitory and facilitatory cortical networks. These effects may be useful therapeutically, but the stimulation intensity may be critical in determining the net effect on cortical excitability.

Modulation of transcranial magnetic stimulation evoked potentials by 30 Hz theta burst stimulation of the cerebellum

Transcranial magnetic stimulation (TMS) has the potential to modify cortical excitability as a therapy for neurological and psychiatric disease. Limitations include the transient and localised nature of the effects. In some situations, where cortical excitability is diffusely abnormal, more widespread modulation of cortical activity is desirable. The cerebellum has extensive connections to cortical areas, via the dentato-thalamo-cortical pathway, and the cerebellum is therefore a promising stimulation site for treating conditions with altered cortical excitability. Previous studies have shown that 50 Hz intermittent theta burst stimulation (iTBS) of the cerebellum increases the amplitude of motor evoked potentials (MEP) obtained from ipsilateral muscles by stimulation of the contralateral motor cortex, while continuous TBS (cTBS) has the opposite effect. In this combined TMS-electroencephalography study, the effects of 30 Hz right cerebellar hemisphere TBS on TMSevoked potentials (TEP) were investigated; in particular the effects on the N100 component, which is thought to reflect intra-cortical inhibition. 16 participants, aged 18-30 years, received 30 Hz iTBS, cTBS or sham TBS with a placebo coil in three separate sessions. MEP and TEP were recorded before and after treatment. Treatment with iTBS resulted in an increase in the amplitude of the N100 compared to sham, without significantly altering MEP amplitudes. cTBS did not significantly modify N100 amplitude and had varying effects on MEP, depending on stimulus intensity. The N100 changes were present diffusely and bilaterally. The findings suggest that 30 Hz cerebellar iTBS enhances activity in both inhibitory and facilitatory cortical networks. These effects may be useful therapeutically, but the stimulation intensity may be critical in determining the net effect on cortical excitability.

Mini-Temporalis Transposition

Facial paralysis is a common craniofacial deformity that is responsible for significant psychological and functional impairment. Free muscle transfer in 2 stages and latissimus dorsi transfer in one stage may be the most effective surgical procedure for achieving a symmetrical spontaneous smile for a patient with complete facial paralysis. However, these 2 procedures are unsuitable for many incomplete patients. The authors introduce a less invasive procedure, termed mini-temporalis transposition that is able to achieve a symmetrical spontaneous smile in incomplete patients. Through a zigzag incision into the temporal region, the middle third of the temporalis is transferred and elongated with the palmaris longus tendon or combined with the deep temporal fascia. The strips are anchored to key points at the modiolus and the middle of the ipsilateral orbicularis oris muscle through a small intraoral incision and subcutaneous tunnel. The key points are marked during preoperative smile analysis. This procedure was applied to 15 patients with long-standing incomplete facial paralysis. All patients obtained improvements in smile symmetry after the operation, and patients' satisfaction was high. In addition, no damage to residual facial nerve functions or development of procedure-induced complications (such as a facial contour defect, lip eversion or puckering, or skin tethering) was observed in any of the patients. Nevertheless, slight temporal hollowing was observed in 4 patients, and mild bulkiness over the zygomatic arch was a common observation. In summary, the mini-temporalis transfer technique is a safe and effective method of smile restoration for long-standing incomplete facial paralysis.

Relative Efficiency of Cochlear Hydrops Analysis Masking Procedure and Cervical Vestibular Evoked Myogenic Potential in Identification of Meniere’s Disease

Cervical vestibular evoked myogenic potential (cVEMP) and cochlear hydrops analysis masking procedure (CHAMP) have both shown sensitivity in identifying Meniere’s disease. However none of the previous reports have compared the two tests for their relative efficacy in identifying Meniere’s disease. Hence the present study aimed to compare the efficiency of cVEMP and CHAMP in evaluating Meniere’s disease. The study included 58 individuals with unilateral definite Meniere’s disease and an equal number of age and gender matched healthy individuals. cVEMP corresponding to 500 Hz tone burst was recorded from ipsilateral sternocleidomastoid muscle and CHAMP was acquired from the conventional electrode sites for single channel auditory brainstem response recording using a default protocol of the Biologic Navigator Pro evoked potential system. Both cVEMP and CHAMP showed statistically significant differences between the groups (P&lt;0.05). The receiver operating curves revealed 100% sensitivity and specificity for CHAMP as against 70.7% sensitivity and 100% specificity for cVEMP in identifying Meniere’s disease. Therefore, CHAMP appears to be the test of choice provided the degree of hearing loss does not exceed a moderate degree. cVEMP could be used for all degrees of hearing losses, but with slight constraint on the sensitivity.

Effect of cerebellar transcranial magnetic stimulation on soleus Ia presynaptic and reciprocal inhibition.

Previously, we reported that cerebellar transcranial magnetic stimulation (C-TMS) facilitates spinal motoneuronal excitability in resting humans. In this study, we aimed to characterize the descending pathway that is responsible for the C-TMS-associated cerebellar spinal facilitation. We evaluated the effect of C-TMS on ipsilateral soleus Ia presynaptic inhibition (PSI) and reciprocal inhibition (RI) because the vestibulospinal and reticulospinal tracts project from the cerebellum to mediate spinal motoneurons via interneurons associated with PSI. PSI and RI were measured with a soleus H-reflex test following operant conditioning using electrical stimulation of the common peroneal nerve. C-TMS was delivered before test tibial nerve stimulation with conditioning-test interstimulus intervals of 110 ms. C-TMS did not generate motor-evoked potentials, and it did not increase electromyography activity in the ipsilateral soleus muscle, indicating that C-TMS does not directly activate the corticospinal tract and motoneurons. However, C-TMS facilitated the ipsilateral soleus H-reflex and reduced the amount of soleus Ia PSI, but not RI. These findings indicate that C-TMS may facilitate the excitability of the spinal motoneuron pool via the vestibulospinal or reticulospinal tracts associated with PSI. Cerebellar spinal facilitation may be useful for assessing the functional connectivity of the cerebellum and vestibular nuclei or reticular formation.

Vestibular examinations in apogeotropic positional nystagmus caused by cerebellar tumor

Horizontal, direction changing apogeotropic positional nystagmus (HAPN) is known to be associated with cerebellar lesions [1]. However, the pathophysiologic mechanism of cerebellar HAPN is unknown. We encountered a patient with a metastatic cerebellar tumor who presented with HAPN that disappeared after tumorectomy. Hyperactive vestibular reflexes, indicated by the results of electrophysiologic examinations, might have been the mechanism underlying the HAPN in this patient. A 70-year-old woman with a 2-month history of progressive dizziness and difficulty in walking was admitted to our hospital. She presented with truncal ataxia and HAPN but no other neurologic or neuroophthalmologic abnormalities. Contrast brain MRI revealed a well-enhanced cerebellar tumor. Because chest X-ray and CT showed a left lung tumor suggestive of lung cancer, a cerebellar metastasis was diagnosed. The cerebellar tumor was removed surgically 10 days after the patient’s admission. Pathologic examination of the surgical specimen revealed adenocarcinoma. After the tumorectomy, the HAPN was fully resolved, and the truncal ataxia was improved. The horizontal angular vestibulo-ocular reflex (A-VOR), cervical vestibular-evoked myogenic potential (C-VEMP), and ocular vestibular-evoked myogenic potential (O-VEMP) were evaluated before (when the HAPN was present) and 10 days after tumorectomy (when the HAPN had disappeared). A-VORs were recorded in darkness by means of a video-oculography-basedVORrecording and analysis system (IRN-2, Morita Mfg. Corp., Kyoto, Japan), with the patient seated on a rotating armchair with a headrest [2]. The chair was rotatedmanually in sinusoidal fashion for 20 s (frequency 0.5–0.75 Hz, amplitude 20 ) [2]. VOR gain, i.e., the eye velocity to head velocity ratio, was analyzed. C-VEMP was recorded from the tonically contracting ipsilateral sternocleidomastoid muscle during monaural stimulation with 105-dB clicks or short tone bursts (MEB 2312 testing system, Nihon Kohden, Tokyo, Japan; bandwidth 20–2,000 Hz, 200 averaged signals). Latencies of the first positive wave (p13) and second negative wave (n23) and peak-to-peak p13–n23 amplitude were measured. O-VEMP was recorded from the lower eyelids (inferior oblique muscles) during stimulation with 105 dB clicks or short tone bursts (MEB 2312, Nihon Kohden, Tokyo, Japan; bandwidth 20–2,000 Hz, 200 averaged signals). The patient was instructed to continue looking straight ahead and upward 30 . Because O-VEMP was not adequately elicited by monaural stimulation, binaural sound stimulation was applied. Latencies of the first negative wave (n1) and second positive wave (p1) and peak-to-peak n1–p1 amplitude were measured. Absolute A-VOR gains were reduced in both directions after the tumorectomy (Table 1). Cand O-VEMP amplitudes were also reduced on almost all recordings after tumorectomy (Table 1). Latencies of Cand O-VEMPs did not change. A-VOR is mediated by a semicircular-ocular pathway. C-VEMP reflects the vertical linear vestibulo-ocular reflex Electronic supplementary material The online version of this article (doi:10.1007/s10072-015-2086-4) contains supplementary material, which is available to authorized users.

Surgical management of dysthyroid diplopia with preservation of the anterior ciliary vascularization: Review of ten cases

During the surgical correction of dysthyroid diplopia, the risk of ischemia by transection of the anterior ciliary arteries is well-known. In order to avoid this, we modified the classical surgical technique: (1) through the preservation of the vascular pedicles during muscle recession and (2) if necessary, through a plication (instead of a resection) of the ipsilateral antagonist muscle. The objective to be achieved is thus the resolution of the diplopia without ischemic complications. We report a prospective series of 10 patients with dysthyroid ophthalmopathy, causing strabismic diplopia, all operated on by the same surgeon (BR) after at least 12 months of euthyroidism. Data collection included: history of previous decompressive surgery, surgical procedure, and oculomotor status before and after surgery. Ten patients (8 females), aged 51 to 74 years (mean age, 58.00 ± 7.62 years), were collected between 2008 and 2012. All patients had one or more vascular risk factors (diabetes, smoking, obesity, high blood pressure). With a follow-up from 16 to 67 months (mean ± SD 27.7 months ± 14.87), surgical outcomes were excellent: diplopia was cured in all cases, with recovery of stereoscopic vision. We had no operative or postoperative complications. The technique of preservation of the anterior ciliary vascularization, which is particularly justified for these fragile patients, is compatible with moderate muscle recessions. For larger deviations, in which a larger recession might increase the proptosis, it is possible to add a plication of the ipsilateral antagonist. This surgical technique made possible the suppression of the diplopia in all cases.

Botulinum toxin injection for treatment of acute traumatic superior oblique muscle palsy

Purpose:To evaluate the outcomes of botulinum toxin injection into the inferior oblique (IO) muscle for management of unilateral acute traumatic superior oblique (SO) palsy.Methods:In this prospective case series, 10-20 units of botulinum toxin A (Dysport, Ipsen, Biopharm Ltd., Wrexham, UK) was injected into the ipsilateral IO muscle of 13 consecutive patients with unilateral acute traumatic SO palsy. All patients received injections within four weeks of the incident.Results:Mean age was 29 ± 15 years and 12 (92%) subjects were male. Mean amount of hypertropia (in primary position) was decreased from 10.0 ± 3.9Δ at baseline to 4.6 ± 8.9Δ, one month after the injection, and to 1.5 ± 2.7Δ at final follow-up (P = 0.001). IO overaction improved from 2.7 ± 0.6 to 1.0 ± 1.2 and 0.6 ± 0.9 (P ≤ 0.001), and subjective torsion from 5.3 ± 3.9 to 3.2 ± 3.4 and 1.6 ± 2.5 degrees (P ≤ 0.001), at the same time intervals respectively. One month after the injection as well as at final follow-up, 10 (77%) patients were diplopia-free in primary and reading positions. Subgroup analysis showed that patients who recovered had less baseline hypertropia as compared to those who failed (8.3Δ vs. 15.7Δ, respectively; P = 0.01). All patients with a favorable outcome had baseline hypertropia of 10Δ or less.Conclusion:A single injection of BTA into the IO muscle can rapidly and safely resolve symptomatic diplopia in patients with acute traumatic SO palsy, while waiting for spontaneous recovery.

Reorganization of spinal neural circuitry and functional recovery after spinal cord injury

Reorganization of spinal neural circuitry and functional recovery after spinal cord injury

Co-firing of levator palpebrae and masseter muscles links the masticatory and oculomotor system in humans.

Simultaneous co-firing of the levator palpebrae (LP) and pterygoid muscles were recorded in Marcus Gann Syndrome (MGS) patients in early clinical studies. “Release hypothesis” proposed an intrinsic masticatory oculomotor neural circuit and this kind circuit, which, however, has been observed only in amphibian. On the other hand, congenital miswiring hypothesis has overwhelmed other interpretations. However, the same phenomenon visualized in MGS cases was unveiled in human subjects without any sign of congenital oculomotor disorder. To further study co-firing of the upper eyelid and jaw muscles, we applied non-invasive EMG recording of the upper eyelid and ipsilateral masseter muscle belly in nine healthy volunteers. LP activity was determined initially by looking upward and active retraction of upper eyelid with head fixed. Then, dual channel inputs from upper eyelid and masseter muscle was recorded during tooth occlusion motivated by isometric masseter muscle contraction without jaw and face moving. The EMG recorded from upper eyelid when the subjects retracted eyelid with head fixed exhibited the same pattern as that collected during tooth occlusion, but the pattern was completely different from EMG of active eye closure. This reflects tooth occlusion evoked LP activity. Then, simultaneous co-firing of the LP and masseter muscle was recorded simultaneously during tooth occlusion without jaw movement. Finally, the aforementioned co-firing was recorded when the subjects conducted rhythmic occlusion and synchronous EMG from both muscles was acquired. In conclusions, humans may also have an intrinsic masticatory oculomotor circuit and release hypothesis may apply, at least, to some cases of MGS.