Intraoperative Electrical Stimulation Research Articles

A New Surgical Option For Patients with Unresolved Bell's Palsy.

This paper describes a new surgical procedure with electrical stimulation of the facial nerve for unresolved Bell's palsy and compares the facial nerve recovery with another group who underwent traditional middle cranial fossa decompression. All patients with total unilateral facial paralysis had surgery by the senior author 3months from onset of Bell's Palsy. Surgical decompression was performed in 13 patients between 1992-2012 (Group 1). Surgical exposure with intraoperative electrical stimulation of the facial nerve in the peri-geniculate region was performed in 47 patients between 2012-2022 (Group 2). The facial recovery at 1month and 3month were significantly better in Group 2. The degree of synkinesis was significantly less in Group 2. The trans-mastoid electrical stimulation of the facial nerve is less invasive, requires no hospital stay, and less time off work compared to the middle cranial fossa approach. The earlier facial movement at one month results in less long-term unwanted faulty regeneration or synkinesis.

Evaluation of long-term results of single intraoperative electrical neurostimulation after autologous plastic surgery of a resection defect of the tibial portion of the sciatic nerve in adult rats

Introduction World literature data indicate the effectiveness of single intraoperative electrical stimulation (IES) of the proximal segment of the damaged nerve to stimulate its regeneration, but there is no data on its effect on the long-term results of autoplasty of resection defects.The purpose of the work was to evaluate the long-term results of a single IES after autologous plastic surgery of the tibial portion of the sciatic nerve in rats.Materials and methods Thirty rats after autologous repair of the resection defect of the tibial portion of the sciatic nerve were divided into series 1 (unstimulated control, n = 16) and series 2 (single IES for 40 minutes, n = 14). At 4 and 6 months after surgery, the static sciatic functional index (SFI) and morphometry of epoxy transverse semithin sections of the tibial nerve at the level of the middle third of the leg were assessed. For comparison with the normal values, the corresponding data from 7 intact rats were used.Results The number of animals with excellent results of SFI restoration was 12.5 % in series 1 and 50 % in series 2 (p = 0.05). The numerical density of regenerated myelinated fibers (MF) exceeded the norm: in series 1 — by 63 % (p < 0.01) and 34 % (p < 0.01), in series 2 — by 58 % (p < 0.01) and 47 % (p < 0.01), respectively. In series 2, there were greater values in comparison with series 1: the median diameters of MFs were by 11.7 % and 15.7 %, the median diameters of their axons were by 5.4 % and 11.9 %, the median thickness of the myelin sheath was by 17.0 % and 24.1 %, respectively (p < 0.05 4 months and p < 0.01 6 months after surgery). Four months after surgery in series 1 and 2, the numerical densities of endoneurial vessels exceeded the intact control by 134 % (p < 0.05) and 156 % ( 0.05), their average diameters by 18 % and 16 % (p < 0.01) respectively, and lumen diameters increased only in series 2 by 8 % (p = 0.07). After 6 months of the experiment in series 1 and 2, the numerical densities of microvessels decreased, but significantly exceeded the control by 66 % (p < 0.05) and 83 % (p < 0.05), the average diameters — by 14 % and 36 % (p < 0.05), lumen diameters — by 26 % (p < 0.05) and 50 % (p < 0.01), respectively.Discussion The difference between stimulated and unstimulated animals in all MF size parameters 6 months after surgery was greater than after 4 months, indicating a persistent neuroregenerative effect.Conclusions A significant increase in the diameters of regenerating nerve fibers in the tibial nerve, as well as the diameters of their axons and the thickness of the myelinated sheaths 4 and 6 months after autoplasty of the tibial portion of the sciatic nerve in the group of animals with a single 40-minute IES of the proximal portion of the sciatic nerve indicates the promoting effect of the applied additive effect on regenerative axono- and myelinogenesis. Increase in the lumens and improvement of blood flow of the endoneurial vessels of the tibial nerve in the series with IES ensured the stability of the neuroregenerative effect. The functional significance of the effects of a single IES is confirmed by a significantly higher percentage of animals with excellent results in restoring the static functional index.

Resting State Functional Networks in Gliomas: Validation With Direct Electric Stimulation of a New Tool for Planning Brain Resections.

Precise mapping of functional networks in patients with brain tumor is essential for tailoring personalized treatment strategies. Resting-state functional MRI (rs-fMRI) offers an alternative to task-based fMRI, capable of capturing multiple networks within a single acquisition, without necessitating task engagement. This study demonstrates a strong concordance between preoperative rs-fMRI maps and the gold standard intraoperative direct electric stimulation (DES) mapping during awake surgery. We conducted an analysis involving 28 patients with glioma who underwent awake surgery with DES mapping. A total of 100 DES recordings were collected to map sensorimotor (SMN), language (LANG), visual (VIS), and speech articulation cognitive domains. Preoperative rs-fMRI maps were generated using an updated version of the ReStNeuMap software, specifically designed for rs-fMRI data preprocessing and automatic detection of 7 resting-state networks (SMN, LANG, VIS, speech articulation, default mode, frontoparietal, and visuospatial). To evaluate the agreement between these networks and those mapped with invasive cortical mapping, we computed patient-specific distances between them and intraoperative DES recordings. Automatically detected preoperative functional networks exhibited excellent agreement with intraoperative DES recordings. When we spatially compared DES points with their corresponding networks, we found that SMN, VIS, and speech articulatory DES points fell within the corresponding network (median distance = 0 mm), whereas for LANG a median distance of 1.6 mm was reported. Our findings show the remarkable consistency between key functional networks mapped noninvasively using presurgical rs-fMRI and invasive cortical mapping. This evidence highlights the utility of rs-fMRI for personalized presurgical planning, particularly in scenarios where awake surgery with DES is not feasible to protect eloquent areas during tumor resection. We have made the updated tool for automated functional network estimation publicly available, facilitating broader utilization of rs-fMRI mapping in various clinical contexts, including presurgical planning, functional reorganization over follow-up periods, and informing future treatments such as radiotherapy.

Prognostic value Analysis of Intraoperative Transcranial Electrical Stimulation motor evoked Potential Monitoring in Postoperative limb Function changes of Neurosurgical Patient

Objective: To explore the predictive value of intraoperative transcranial electrical stimulation motor evoked potential (TES-MEP) monitoring for postoperative muscle strength change in patients undergoing craniocerebral surgery. Methods: In this study, 166 patients who underwent intraoperative motor evoked potential (MEP) monitoring were retrospectively analyzed. Univariate analysis and binary Logistic regression were used to analyze the influencing factors of postoperative muscle strength changes. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of abnormal changes of MEP amplitude in postoperative muscle strength changes. Results: Binary Logistic regression analysis showed that the abnormal amplitude of MEP during operation was an independent risk factor for short-term and long-term muscle strength decline after operation (P < 0.05). ROC curve analysis showed that the area under the curve (AUC) for abnormal changes of MEP amplitude to predict short-term postoperative muscle strength decline was 0.754, with a sensitivity of 0.516, with a specificity of 0.993, and the AUC for long-term postoperative was 0.782, with a sensitivity of 0.591 and specificity of 0.972. Conclusions: The decrease of MEP amplitude more than 50% as a warning standard has a good predictive value for the change of limb function after operation, and the abnormal changes of MEP amplitude indicate that the muscle strength of patients after operation may be lower than that before operation.

Comparative validation of automated presurgical tractography based on constrained spherical deconvolution and diffusion tensor imaging with direct electrical stimulation.

Accurate presurgical brain mapping enables preoperative risk assessment and intraoperative guidance. This cross-sectional study investigated whether constrained spherical deconvolution (CSD) methods were more accurate than diffusion tensor imaging (DTI)-based methods for presurgical white matter mapping using intraoperative direct electrical stimulation (DES) as the ground truth. Five different tractography methods were compared (three DTI-based and two CSD-based) in 22 preoperative neurosurgical patients undergoing surgery with DES mapping. The corticospinal tract (CST, N = 20) and arcuate fasciculus (AF, N = 7) bundles were reconstructed, then minimum distances between tractograms and DES coordinates were compared between tractography methods. Receiver-operating characteristic (ROC) curves were used for both bundles. For the CST, binary agreement, linear modeling, and posthoc testing were used to compare tractography methods while correcting for relative lesion and bundle volumes. Distance measures between 154 positive (functional response, pDES) and negative (no response, nDES) coordinates, and 134 tractograms resulted in 860 data points. Higher agreement was found between pDES coordinates and CSD-based compared to DTI-based tractograms. ROC curves showed overall higher sensitivity at shorter distance cutoffs for CSD (8.5 mm) compared to DTI (14.5 mm). CSD-based CST tractograms showed significantly higher agreement with pDES, which was confirmed by linear modeling and posthoc tests (PFWE < .05). CSD-based CST tractograms were more accurate than DTI-based ones when validated using DES-based assessment of motor and sensory function. This demonstrates the potential benefits of structural mapping using CSD in clinical practice.

Motor or non-motor speech interference? A multimodal fMRI and direct cortical stimulation mapping study

We retrospectively analyzed data from 15 patients, with a normal pre-operative cognitive performance, undergoing awake surgery for left fronto-temporal low-grade glioma. We combined a pre-surgical measure (fMRI maps of motor- and language-related centers) with intra-surgical measures (MNI-registered cortical sites data obtained during intra-operative direct electrical stimulation, DES, while they performed the two most common language tasks: number counting and picture naming).Selective DES effects along the precentral gyrus/inferior frontal gyrus (and/or the connected speech articulation network) were obtained. DES of the precentral gyrus evoked the motor speech arrest, i.e., anarthria (with apparent mentalis muscle movements). We calculated the number of shared voxels between the lip-tongue and overt counting related- and silent naming-related fMRI maps and the Volumes of Interest (VOIs) obtained by merging together the MNI sites at which a given speech disturbance was observed, normalized on their mean the values (i.e., Z score). Both tongue- and lips-related movements fMRI maps maximally overlapped (Z = 1.05 and Z = 0.94 for lips and tongue vs. 0.16 and −1.003 for counting and naming) with the motor speech arrest seed. DES of the inferior frontal gyrus, pars opercularis and the rolandic operculum induced speech arrest proper (without apparent mentalis muscle movements). This area maximally overlapped with overt counting-related fMRI map (Z = −0.11 and Z = 0.09 for lips and tongue vs. 0.9 and 0.0006 for counting and naming). Interestingly, our fMRI maps indicated reduced Broca's area activity during silent speech compared to overt speech. Lastly, DES of the inferior frontal gyrus, pars opercularis and triangularis evoked variations of the output, i.e., dysarthria, a motor speech disorder occurring when patients cannot control the muscles used to produce articulated sounds (phonemes). Silent object naming-related fMRI map maximally overlapped (Z = −0.93 and Z = −1.04 for lips and tongue vs. −1.07 and 0.99 for counting and naming) with this seed.Speech disturbances evoked by DES may be thought of as selective interferences with specific recruitment of left inferior frontal gyrus and precentral cortex which are differentiable in terms of the specific interference induced.

Adult traumatic brachial plexus injuries: advances and current updates.

Nerve grafting, tendon transfer and joint fusion are routinely used to improve the upper limb function in patients with brachial plexus palsies. Newer techniques have been developed that provide additional options for reconstruction. Nerve transfer is a tool for restoring upper limb function in total root avulsions where nerve grafting is not possible. In partial brachial plexus injuries, nerve transfers can greatly improve shoulder, elbow, wrist and hand function. Intraoperative electrical stimulation can be used to diagnose precisely which nerve is injured and to choose which nerve fascicles should be transferred. Finally, measuring the postoperative outcome can improve the evaluation of our techniques. The aim of this article was to present the current techniques used to treat patients with brachial plexus injury.

Rare median and musculocutaneous nerve fusion with intraoperative electrical confirmation: illustrative case

BACKGROUND Nerve transfer is a surgical technique in which a redundant or expendable fascicle is transferred or coapted to an injured nerve distal to the site of injury for the purpose of reinnervation. Successful nerve transfer is dependent on correct intraoperative identification of donor and recipient nerves. OBSERVATIONS An 8-year-old male was recommended for ulnar nerve fascicle to biceps branch of musculocutaneous nerve transfer to restore elbow flexion weakness after a demyelinating spinal cord injury. The biceps branch was identified approximately midway along the upper arm. Proximal musculocutaneous nerve stimulation induced hand movement and electromyography activity in the median nerve muscles. Neurolysis of the thickened proximal structure revealed fusion of the musculocutaneous and median nerves. Because of the proximity of the median and musculocutaneous nerves, median rather than ulnar nerve fascicles were used as donors for transfer. LESSONS The authors provide the first reported intraoperative finding of an anatomical variant in which the musculocutaneous nerve and median nerve were fused in the upper arm, confirmed through intraoperative electrical stimulation. Surgeons should be aware of this rare anatomical variant to ensure correct nerve identification when performing nerve transfers in the proximal upper extremity.

Convergence of the arcuate fasciculus and third branch of the superior longitudinal fasciculus with direct cortical stimulation-induced speech arrest area in the anterior ventral precentral gyrus.

The objective was to identify the correspondence between the anterior terminations of the arcuate fasciculus (AF) and third branch of the superior longitudinal fasciculus (SLF-III) and the intraoperative direct cortical electrical stimulation (DCS)-induced speech arrest area. The authors retrospectively screened 75 glioma patients (group 1) who received intraoperative DCS mapping in the left dominant frontal cortex. To minimize the influence of tumors or edema, we subsequently selected 26 patients (group 2) with glioma or edema not affecting Broca's area, the ventral precentral gyrus (vPCG), and the subcortical pathways to generate DCS functional maps and to construct the anterior terminations of AF and SLF-III with tractography. Next, a grid-by-grid pairwise comparison was performed between the fiber terminations and the DCS-induced speech arrest sites to calculate Cohen's kappa coefficient (κ) in both groups 1 and 2. Finally, the authors also demonstrated the distribution of the AF/SLF-III anterior projection maps obtained in 192 healthy participants (group 3) and subsequently correlated these with the speech arrest sites in group 2 to examine their validity in predicting speech output area. The authors found that speech arrest sites were substantially consistent with SLF-III anterior terminations (group 1, κ = 0.64 ± 0.03; group 2, κ = 0.73 ± 0.05) and moderately consistent with AF (group 1, κ = 0.51 ± 0.03; group 2, κ = 0.49 ± 0.05) and AF/SLF-III complex (group 1, κ = 0.54 ± 0.03; group 2, κ = 0.56 ± 0.05) terminations (all p < 0.0001). The DCS speech arrest sites of the group 2 patients mainly (85.1%) emerged at the anterior bank of the vPCG (vPCGa). In group 3, both terminations of AF and SLF-III converged onto the vPCGa, and their terminations well predicted the DCS speech output area of group 2 (AF, area under the curve [AUC] 86.5%; SLF-III, AUC 79.0%; AF/SLF-III complex, AUC 86.7%). This study supports the key role of the left vPCGa as the speech output node by showing convergence between speech output mapping and anterior AF/SLF-III connectivity in the vPCGa. These findings may contribute to the understanding of speech networks and could have clinical implications in preoperative surgical planning.

Comparison of Motor Evoked Potentials Neuromonitoring Following Pre- and Postoperative Transcranial Magnetic Stimulation and Intraoperative Electrical Stimulation in Patients Undergoing Surgical Correction of Idiopathic Scoliosis.

The relationships between the results of pre- and intraoperative motor evoked potential recordings during neuromonitoring and whether idiopathic scoliosis (IS) surgical correction improves the spinal efferent transmission have not been specified in detail. This study aims to compare the results of surface-recorded electromyography (EMG), electroneurography (ENG, M, and F-waves), and especially motor evoked potential (MEP) recordings from tibialis anterior muscle (TA) bilaterally in 353 girls with right idiopathic scoliosis (types 1-3 according to Lenke classification). It has not yet been documented whether the results of MEP recordings induced by transcranial single magnetic stimulus (TMS, pre- and postoperatively) and trains of electrical stimuli (TES; intraoperatively in T0-before surgery, T1-after pedicle screws implantation, and T2-after scoliosis curvature distraction and derotation following two-rod implantation) can be compared for diagnostic verification of the improvement of spinal cord neural transmission. We attempted to determine whether the constant level of optimal anesthesia during certain surgical steps of scoliosis treatment affects the parameters of MEPs recorded during neuromonitoring procedures. No neurological deficits have been observed postoperatively. The values of amplitudes but not latencies in MEP recordings evoked with TMS in IS patients compared before and after surgery indicated a slight improvement in efferent neural transmission. The results of all neurophysiological studies in IS patients were significantly asymmetrical and recorded worse on the concave side, suggesting greater neurological motor deficits at p = 0.04. The surgeries brought significant improvement (p = 0.04) in the parameters of amplitudes of sEMG recordings; however, the consequences of abnormalities in the activity of TA motor units were still reflected. ENG study results showed the symptoms of the axonal-type injury in peroneal motor fibers improving only on the concave side at p = 0.04, in parallel with F-wave parameters, which suggests that derotation and distraction might result in restoring the proper relations of the lumbar ventral roots in the spinal central canal, resembling their decompression. There were no significant differences detected in the amplitudes or latencies of MEPs induced with TMS or TES when comparing the parameters recorded preoperatively and intraoperatively in T0. The amplitudes of TES-evoked MEPs increased gradually at p = 0.04 in the subsequent periods (T1 and T2) of observation. A reduction in MEP latency at p = 0.05 was observed only at the end of the IS surgery. Studies on the possible connections between the level of anesthesia fluctuations and the required TMS stimulus strength, as well as the MEP amplitude changes measured in T0-T2, revealed a lack of relationships. These might not be the factors influencing the efferent transmission in spinal pathways beside the surgical procedures. Pre- (TMS-evoked) and intraoperative (TES-evoked) recordings are reliable for evaluating the patient's neurological status before and during surgical scoliosis correction procedures. An increase in MEP amplitude parameters recorded on both sides after scoliosis surgery proves the immediate improvement of the total efferent spinal cord transmission. Considering comparative pre- and postoperative sEMG and ENG recordings, it can be concluded that surgeries might directly result in additional lumbar ventral root decompression. We can conclude that MEP parameter changes are determined by the surgery procedures during neuromonitoring, not the anesthesia conditions if they are kept stable, which influences a decrease in the number of false-positive neuromonitoring warnings.

The parietal architecture binding cognition to sensorimotor integration: a multimodal causal study.

Despite human's praxis abilities are unique among primates, comparative observations suggest that these cognitive motor skills could have emerged from exploitation and adaptation of phylogenetically older building blocks, namely the parieto-frontal networks subserving prehension and manipulation. Within this framework, investigating to which extent praxis and prehension-manipulation overlap and diverge within parieto-frontal circuits could help in understanding how human cognition shapes hand actions. This issue has never been investigated by combining lesion mapping and direct electrophysiological approaches in neurosurgical patients. To this purpose, 79 right-handed left-brain tumour patient candidates for awake neurosurgery were selected based on inclusion criteria. First, a lesion mapping was performed in the early postoperative phase to localize the regions associated with an impairment in praxis (imitation of meaningless and meaningful intransitive gestures) and visuo-guided prehension (reaching-to-grasping) abilities. Then, lesion results were anatomically matched with intraoperatively identified cortical and white matter regions, whose direct electrical stimulation impaired the Hand Manipulation Task. The lesion mapping analysis showed that prehension and praxis impairments occurring in the early postoperative phase were associated with specific parietal sectors. Dorso-mesial parietal resections, including the superior parietal lobe and precuneus, affected prehension performance, while resections involving rostral intraparietal and inferior parietal areas affected praxis abilities (covariate clusters, 5000 permutations, cluster-level family-wise error correction P < 0.05). The dorsal bank of the rostral intraparietal sulcus was associated with both prehension and praxis (overlap of non-covariate clusters). Within praxis results, while resection involving inferior parietal areas affected mainly the imitation of meaningful gestures, resection involving intraparietal areas affected both meaningless and meaningful gesture imitation. In parallel, the intraoperative electrical stimulation of the rostral intraparietal and the adjacent inferior parietal lobe with their surrounding white matter during the hand manipulation task evoked different motor impairments, i.e. the arrest and clumsy patterns, respectively. When integrating lesion mapping and intraoperative stimulation results, it emerges that imitation of praxis gestures first depends on the integrity of parietal areas within the dorso-ventral stream. Among these areas, the rostral intraparietal and the inferior parietal area play distinct roles in praxis and sensorimotor process controlling manipulation. Due to its visuo-motor 'attitude', the rostral intraparietal sulcus, putative human homologue of monkey anterior intraparietal, might enable the visuo-motor conversion of the observed gesture (direct pathway). Moreover, its functional interaction with the adjacent, phylogenetic more recent, inferior parietal areas might contribute to integrate the semantic-conceptual knowledge (indirect pathway) within the sensorimotor workflow, contributing to the cognitive upgrade of hand actions.

Removal of grade IV vestibular schwannomas by retrosigmoid approach: results of a cumulative series of two European centers

Introduction The aim of our study was to study the association between end-of-surgery facial nerve stimulation threshold and extent of tumor resection in case of grade IV vestibular schwannomas. Materials and methods Grade IV VSs represent a surgical challenge as a risk/benefit ratio must be considered in balancing a satisfactory extent of resection against a good postoperative functional outcome. We reviewed a cumulative series of 57 patients with large/giant VSs who were operated on by retrosigmoid approach in the period from 2008 to 2018 in two European centers, namely San Filippo Neri Hospital, Rome, Italy and Masaryk Hospital, Usti nad Labem, Czech Republic. Extent of resection, intraoperative direct electrical stimulation threshold of facial nerve and postoperative facial outcome were examined. Results Total or near-total resection was accomplished in 40 (75.5%) cases. Two groups were compared: total or near-total resection (T + NT) and subtotal resection (ST); the end-of-surgery facial nerve stimulation threshold significantly differed (T + NT: 0.24 mA, ST: 0.44 mA, p = 0.036). A critical cutoff was found at 0.2mA; values similar or inferior to this correctly predicted total or near-total resection in 86.7% of cases. Thirty (56.6%) patients had a normal postoperative facial outcome (HB1). Among the 40 patients in T + NT group, 32 (80%) retained an acceptable facial function (HB1-2). Conclusions Lower facial nerve stimulation thresholds positively predict a broader extent of resection and total or -near total resection should be accomplished in such cases. Judicious (subtotal) resection is preferred if threshold values increase while dissecting firmly adherent tumors.

A reduced graphene oxide functionalized electrospun nerve wrap: Amalgamating electrical and biochemical cues to enhance nerve regeneration in median nerve injury model

Nerve injuries leads to severe impairment of target tissue and standard treatment approaches from surgery to electrical stimulation are complex, yielding only brief relief. The current study addresses such limitations with reduced graphene oxide (rGO) functionalized “Electroband”. We attempt to conjugate electrical cues in the nerve wrap with in-situ electrical stimulation in a median nerve injury model in rats, underlining the significance of combinatorial therapy for nerve regeneration. “Electroband” targets three critical aspect of nerve regeneration: neuroprotection, neuroregeneration and neuroplasticity at single stroke. The nanofibrous extracellular matrix mimicking nature of “Electroband” assisted in reconciling the injured niche by preventing anoikis, exerting neuroprotective effect as depicted with aligned growth of compressed nerve fibers. The rGO functionalization coupled with intraoperative electrical stimulation of 3 V @ 20 Hz for 10 min aided in propelling the injured nerve to denervated target, prompting fascicular growth of nerve fibers, targeting neuroplasticity. The nerve growth factor incorporation enhanced the bioactivity of scaffold, augmenting regeneration leading to exuberant growth and myelination of nascent nerve tracts. These results led to significant improvement in electrophysiological recordings with 30–32 mV CMAP value (80% recovery) in combinatorial therapy group as compared to 10–11 mV in negative controls and 13–15 mV in animals with individual therapy. We therefore, report 80% regain in muscular strength within 8 weeks of implantation with combinatorial therapy as assessed with behavioural paw gripping and scratch tape assay. Thus, we successfully demonstrated the pre-clinical efficacy of “Electroband”, reducing the time and frequency of electrical stimulation currently in clinical practice.

Quantitative Validation of the Correlation Between Optimized Pyramidal Tract Delineation After Brain Shift Compensation and Direct Electrical Subcortical Stimulation During Brain Tumor Surgery.

It remains unclear whether tractography of pyramidal tracts is correlated with the intraoperative direct electrical subcortical stimulation (DESS), and brain shift further complicates the issue. The objective of this research is to quantitatively verify the correlation between optimized tractography (OT) of pyramidal tracts after brain shift compensation and DESS during brain tumor surgery. OT was performed for 20 patients with lesions in proximity to the pyramidal tracts based on preoperative diffusion-weighted magnetic resonance imaging. During surgery, tumor resection was guided by DESS. A total of 168 positive stimulation points and their corresponding stimulation intensity thresholds were recorded. Using the brain shift compensation algorithm based on hierarchical B-spline grids combined with a Gaussian resolution pyramid, we warped the preoperative pyramidal tract models and used receiver operating characteristic (ROC) curves to investigate the reliability of our brain shift compensation method based on anatomic landmarks. Additionally, the minimum distance between the DESS points and warped OT (wOT) model was measured and correlated with DESS intensity threshold. Brain shift compensation was achieved in all cases, and the area under the ROC curve was 0.96 in the registration accuracy analysis. The minimum distance between the DESS points and the wOT model was found to have a significantly high correlation with the DESS stimulation intensity threshold (r = 0.87, P < 0.001), with a linear regression coefficient of 0.96. Our OT method can provide comprehensive and accurate visualization of the pyramidal tracts for neurosurgical navigation and was quantitatively verified by intraoperative DESS after brain shift compensation.

Intraoperative Biceps/Brachialis Stimulation for Snapping Triceps With Ulnar Neuritis.

Snapping of the triceps muscle occurs when a portion of the medial head dislocates over the medial epicondyle with elbow flexion. Resection or redirection of a portion of the triceps muscle is the main surgical treatment. The extent of triceps resection/redirection is difficult to evaluate. A novel intraoperative technique, stimulating the musculocutaneous nerve, to simulate active elbow flexion is proposed to help ensure that the snapping triceps has been adequately treated. A patient presented with a several year history of bilateral elbow pain, snapping, and ulnar nerve (UN) paresthesias. Previous staged bilateral subcutaneous UN transpositions were performed at another institution for documented UN dislocation and neuritis. Postoperatively symptoms of painful snapping persisted. Bilateral snapping triceps was diagnosed. The left elbow was reoperated. Intraoperative electrical stimulation of the musculocutaneous nerve was performed to reproduce the snapping triceps. Activation of the biceps/brachialis muscles produced powerful elbow flexion, allowed direct visualization of the forceful snapping triceps, and helped assess the adequacy of muscle resection/redirection. Intraoperative biceps/brachialis stimulation can potentially help determine how much triceps muscle should be resected/redirected to treat patients with snapping triceps.

Broad and Asymmetric Lower Extremity Myotomes: Results From Intraoperative Direct Electrical Stimulation of the Lumbosacral Spinal Roots.

Retrospective review of prospectively collected data. This study aimed to accurately map the lower extremity muscles innervated by the lumbar spinal roots by directly stimulating the spinal roots during surgery. Innervation of the spinal roots in the lower extremities has been estimated by clinical studies, anatomic studies, and animal experiments. However, there have been discrepancies between studies. Moreover, there are no studies that have studied the laterality of lower limb innervation. In 73 patients with lumbar degenerative disease, a total of 147 spinal roots were electrically stimulated and the electromyographic response was recorded at the vastus medialis (VM), gluteus medius (GM), tibialis anterior (TA), biceps femoris (BF), and gastrocnemius (GC). The asymmetry index (AI) was obtained using the following equation to represent the left-right asymmetry in the compound muscle action potential (CMAP) amplitude. Paired t tests were used to compare CMAP amplitudes on the right and left sides. Differences in the AI among the same spinal root groups were determined using one-way analysis of variance. The frequency of CMAP elicitation in VM, GM, TA, BF, and GC were 100%, 75.0%, 50.0%, 83.3%, and 33.3% in L3 spinal root stimulation, 90.4%, 78.8%, 59.6%, 73.1%, and 59.6% in L4 spinal root stimulation, 32.2%, 78.0%, 93.2%, 69.5%, and 83.1% in L5 spinal root stimulation, and 40.0%, 100%, 80.0%, 70.0%, and 80.0% in S1 spinal root stimulation, respectively. The most frequent muscle with maximum amplitude of the CMAP in L3, L4, L5, and S1 spinal root stimulation was the VM, GM, TA, and GM, respectively. Unilateral innervation occurred at high rates in the TA in L4 root stimulation and the VM in L5 root stimulation in 37.5% and 42.3% of patients, respectively. Even in patients with bilateral innervation, a 20% to 38% AI of CMAP amplitude was observed. The spinal roots innervated a much larger range of muscles than what is indicated in general textbooks. Furthermore, a non-negligible number of patients showed asymmetric innervation of lower limb by the lumbar spinal roots.

Intraoperative Hemi-Diaphragm Electrical Stimulation Demonstrates Attenuated Mitochondrial Function without Change in Oxidative Stress in Cardiothoracic Surgery Patients.

Mechanical ventilation during cardiothoracic surgery is life-saving but can lead to ventilator-induced diaphragm dysfunction (VIDD) and prolong ventilator weaning and hospital length of stay. Intraoperative phrenic nerve stimulation may preserve diaphragm force production to offset VIDD; we also investigated changes in mitochondrial function after stimulation. During cardiothoracic surgeries (n = 21), supramaximal, unilateral phrenic nerve stimulation was performed every 30 min for 1 min. Diaphragm biopsies were collected after the last stimulation and analyzed for mitochondrial respiration in permeabilized fibers and protein expression and enzymatic activity of biomarkers of oxidative stress and mitophagy. Patients received, on average, 6.2 ± 1.9 stimulation bouts. Stimulated hemidiaphragms showed lower leak respiration, maximum electron transport system (ETS) capacities, oxidative phosphorylation (OXPHOS), and spare capacity compared with unstimulated sides. There were no significant differences between mitochondrial enzyme activities and oxidative stress and mitophagy protein expression levels. Intraoperative phrenic nerve electrical stimulation led to an acute decrease of mitochondrial respiration in the stimulated hemidiaphragm, without differences in biomarkers of mitophagy or oxidative stress. Future studies warrant investigating optimal stimulation doses and testing post-operative chronic stimulation effects on weaning from the ventilator and rehabilitation outcomes.

Intraoperative electrical stimulation for persistent, post-traumatic facial paralysis.

Approximately 7-10% of temporal bone fractures result in facial nerve paralysis. Treatment is dependent upon the severity of the nerve trauma and can range from conservative medical management to surgical intervention. A study by Hato et al. detailed the relationship between surgical timing and recovery rate for patients with facial nerve palsy secondary to temporal bone trauma. The rates of complete recovery and good recovery decline that the longer surgical intervention is delayed. We present the case of a 14-year-old male with a temporal bone fracture and delayed onset right-sided facial paralysis. This patient was treated with a transmastoid middle cranial fossa (MCF) approach with intraoperative electrical stimulation of the perigeniculate portion of the facial nerve. Despite a 53-day delay between trauma and surgical intervention, the patient's facial function improved from House Brackmann (HB) grade VI to grade II within 6months. Intraoperative facial nerve stimulation, which we have previously used for unresolved Bell's palsy, may be useful for patients with post-traumatic, persistent facial paralysis.

Distal Nerve Exploration in the Palm Avoids Nerve Transfer in a Posttraumatic Ulnar Nerve Injury with a Claw Hand

AbstractPosttraumatic low ulnar nerve injuries develop claw hand and poor hand function. Transferring the opponens pollicis branch of the thenar branch at the palm to the terminal division of the deep branch of the ulnar nerve is an effective distal nerve transfer to restore pinch in low ulnar nerve injuries. The author describes the surgical technique for a 4-month-old low ulnar nerve injury in a 25-year-old man with inconclusive electrodiagnostic findings and no clinical findings of distal nerve recovery. The intraoperative electrical stimulation of the nerve in the palm is a simple method to ensure the reinnervation of the ulnar nerve in a claw hand and muscle wasting. Therefore, all postcut injuries with a low ulnar nerve palsy with claw hands may not need a distal nerve transfer. However, performing distal nerve exploration in the palm is vital in cases of doubtful nerve recovery in a low ulnar nerve palsy with a claw hand.

Intraoperative electrical stimulation promotes the short-term recovery of patients with cubital tunnel syndrome after surgery

BackgroundThis study was designed to investigate whether intraoperative electrical nerve stimulation has effects on the short-term recovery of cubital tunnel syndrome patients after ulnar nerve release.MethodsPatients diagnosed as cubital tunnel syndrome were selected. At the same time, they received conventional surgery treatment. The patients were divided by a randomized digits table into two groups. The control group underwent conventional surgery, and the electrical stimulation (ES) group underwent intraoperative electrical stimulation. All the patients were tested for sensory and motor functions, grip strength, key pinch strength, motor conductivity velocity (MCV), and maximum compound muscle action potential (CMAP) before operation and 1 month and 6 months after operation.ResultsIn patients treated with intraoperative ES, the sensory and motor functions and the strength of muscle were significantly improved after 1-month and 6-month follow-up than the control group. After the follow-up, the patients in the ES group had significantly higher grip strength and key pinch strength than the control group. After the follow-up, the patients in the ES group had significantly higher MCV and CMAP than the control group.ConclusionIntraoperative electrical stimulation of nerve muscle can significantly promote the short-term recovery of nerve and muscle functions after the surgery in cubital tunnel syndrome patients.