Nerve Size Research Articles

Does size of the cochlear nerve affect postoperative auditory performance in pediatric cochlear implant patients with normal cochlear nerves?

IntroductionCochlear implantation is an effective treatment method for severe to profound hearing loss. Many factors that may influence cochlear implantation success have been explained in previous studies. Apart from those, minor differences in size of normal cochlear nerves may affect postoperative performance. ObjectiveTo investigate whether the minor differences in cochlear nerve size in normal cochlear nerves affect postoperative cochlear implant performance. Methods30 pediatric prelingually deaf patients who were treated with cochlear implantation were included in this study. From the reconstructed parasagittal magnetic resonance images, the diameter and cross-sectional area of the cochlear nerve on the ipsilateral and contralateral side were measured. Auditory evaluations were performed 1, 3, 6 and 12 months following the first fitting. All the analysis was performed by using EARS®, evaluation of auditory responses to speech tool. Correlation between cochlear nerve diameter, cross-sectional area and postoperative auditory perception was analyzed to determine whether variation in cochlear nerve size contributes to postoperative auditory performance. ResultsThe mean diameter of the cochlear nerve on the ipsilateral side was 718.4 μm (504.5 − 904.3 μm) and mean cross sectional area was 0.015 cm2 (0.012 − 0.018 cm2). On the contralateral side the mean cochlear nerve diameter was 714.4 μm (502.6 − 951.4 μm) and mean cross sectional area was 0.014 cm2 (0.011 − 0.019 cm2). The correlation between the diameter and cross-sectional area of the ipsilateral and contralateral cochlear nerve revealed no significance. Mean score at first month monosyllable-trochee-polysyllable test, MTP1, was 0.17 (0.08 − 0.33), at 6th month with 6 words test, 6th month MTP6 was 0.72 (0.39 − 1.0), at 6th month with 12 words, 6th month MTP 12 was 0.46 (0.17 − 0.75) and at 12th month with 12 words, 12th month MTP12 was 0.73 (0.25 − 1.0). There was no correlation between the monosyllable-trochee-polysyllable test, values at any time with the diameter of the ipsilateral cochlear nerve. However, the first month MTP, 6th month MTP6 and 12th month MTP12 correlated with the cross-sectional area of the ipsilateral cochlear nerve. ConclusionMeasuring the cross sectional area of the normal- appearing cochlear nerve may give important prognostic knowledge on cochlear implant outcomes. In patients with a larger cross sectional area the auditory performance was better and faster. Although normal appearing, slight differences on cross sectional area of the cochlear nerve may affect performance. Measuring the size of the cochlear nerve on parasagittal magnetic resonance images may provide beneficial information on the postoperative rehabilitation process.

Sural Nerve Size in Fibromyalgia Syndrome: Study on Variables Associated With Cross-Sectional Area.

Increased cross-sectional area (CSA) of sural nerve, documented by ultrasound (US), has been revealed in small fibers neuropathy, condition present in about half of patients with fibromyalgia (FM). The aims of this study were to evaluate sural nerve CSA and to establish the variables associated with increased CSA in FM patients. A cross-sectional assessment was conducted in consecutive FM patients. Demographic data, clinimetric parameters [Fibromyalgia Impact Questionnaire (FIQR)], the neuropathic pain features [PainDetect Questionnaire (PDQ)], and the sural nerve CSA were recorded. CSA was determined by US, examining the sural nerve at the lateral region of the calf. CSA was compared with demographic and clinical variables. A multiple regression analysis was conducted applying CSA as dependent variable. One hundred and ten FM patients were enrolled. Sural nerve CSA showed a significant association with body mass index (BMI) (r = 0.422; p < 0.0001) and with PDQ (r = 0.361; p = 0.0001). The multiple regression analysis confirmed that BMI (p = 0.0001) and PDQ (p = 0.0028) were the two independent variables associated with CSA. The severity of the disease, measured with FIQR, showed no association. An increase in sural nerve CSA is closely related to BMI and to distinctive neuropathic symptoms. Overweight and obesity appear to be associated with a FM phenotype with documented peripheral nervous system involvement. Ultrasound examination of the sural nerve at calf level may reveal useful information in patients with FM, identifying a cluster of patients with peripheral nervous system alterations. This cluster of patients is generally overweight or obese, and complains of painful symptoms with neuropathic features.

Ultrasound Detection of Vagus Nerve Atrophy in Bulbar Amyotrophic Lateral Sclerosis.

Neuromuscular ultrasound in amyotrophic lateral sclerosis (ALS) is of increasing interest. As bulbar symptoms are commonly developed by most ALS patients during disease, the aim of our study was to find possible sonographic changes of vagus nerve size in bulbar affected ALS patients. We investigated 24 ALS patients and 19 controls without neuromuscular disorders. In ALS patients, bulbar affection was documented clinically (eg, dysarthria, dysphagia, and fasciculations) or subclinically using ultrasound and electromyography of bulbar muscles. Vagus nerve ultrasound was performed in all participants bilaterally at the level of the thyroid gland. The cross-sectional area (CSA) of the vagus nerve in bulbar affected ALS patients (mean CSA right/left 1.9 ± .7 mm²/1.8 ± .6 mm²) was significantly reduced on both sides compared to controls (mean CSA right/left 2.2 ± .6 mm²/2.0 ± .3 mm²) - right: P = .0387, left: P = .0386. Receiver operating characteristic curve analysis of the vagus nerve CSA yielded a sensitivity of 66.7% and a specificity of 63.2% (cutoff value 1.85 mm²). Vagus nerve CSA did not correlate significantly with age in controls (right: P = .45, left: P = .66). In controls and ALS patients, there was no significant difference of vagus nerve CSA between the right and left sides (controls: P = .43; patients: P = .86). Our study demonstrates vagus nerve atrophy in bulbar affected ALS patients. Further studies are warranted investigating the relevance of our finding for monitoring disease progression in ALS.

Ultrasound and magnetic resonance imaging evaluation of the femoral and sciatic nerves. A study of healthy volunteers.

Background and aimsThe study describes the femoral (FN) and sciatic nerves (SN), explored using ultrasound (US) and magnetic resonance imaging (MRI). The aims of the study are: to establish US/MRI correlations and define reference values: for the anteroposterior (AP) and mediolateral (ML) diameters and cross-sectional area (CSA) of the two nerves respectively, in well-defined anatomical measuring sites; to analyze the intraobserver variation; to define the value with least variability; to determine differences between the right-left and male-female reference values.MethodsA prospective study was carried out on 24 healthy volunteers (11 men and 13 women). MRI scans were performed using a 1.5T system. To visualize both nerves (FN and SN), a single 3D T2 weighted acquisition was performed, in the coronal plane, with a wide FOV. For ultrasonographic examinations, a Hitachi EUB-8500 ultrasound machine, equipped with a 13 MHz linear transducer was used. The measurements were performed at well-defined anatomical locations. The mean reference values of the AP, ML diameters and CSA were calculated for femoral and sciatic nerves, both on MRI and US. The correlations between the values determined by the two techniques were analyzed. The intra-observer variation was calculated by measuring the nerves at the same anatomical location at two separate time points.ResultsWilcoxon matched-pairs signed rank test indicated a non-significant difference (p> 0.05) for the femoral and sciatic nerves, on both sides, except the femoral nerve ML diameter on MRI (p=0.014). The mean MRI and US reference values for the femoral nerve were calculated between the psoas and iliac muscles: FNAPMRI 4.533 ± 0.486, FNAPUS 4.800 ± 1.237, FNMLMRI 6.172 ± 1.203, FNMLUS 7.685 ± 3.338, FNCSAMRI 24.811 ± 3.394, FNCSAUS 26.285 ± 17.608. The mean MRI and US measurements for the sciatic nerve were determined under the buttock, at the level of the ischial tuberosity: SNAPMRI 5.500 ± 1.201, SNAPUS 5.975 ± 1.312, SNMLMRI 10.375 ± 2.272, SNMLUS 13.500 ± 1.661, SNCSAMRI 50.625 ± 15.373, SNCSAUS 53.631 ± 15.847. The MRI and US differences between right and left sides, both for the femoral and sciatic nerves were insignificant. In selected cases, Wilcoxon paired test indicated differences between subjects, according to their gender, both on MRI and US.ConclusionReference values for the femoral and sciatic nerves at specific anatomical sites were identified. Side to side variation and gender related differences add to current knowledge on nerve size in young Caucasian population.

Vagus Nerve Ultrasound in Chronic Inflammatory Demyelinating Polyradiculoneuropathy and Charcot-Marie-Tooth Disease Type 1A.

Both clinical autonomic dysfunction and involvement of autonomic nerves have been reported in a range of peripheral nerve disorders. We employed nerve ultrasound to assess the size of the vagus nerve in a serial study of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Charcot-Marie-Tooth type 1B (CMT1B) as compared to healthy controls (HCs). We correlated these findings with involvement of the median and ulnar nerves. Forty-three patients with CIDP, 8 with CMT1A, and 105 HC were prospectively recruited. The cross-sectional areas (CSAs) of the vagus, median, and ulnar nerves were measured bilaterally. The alteration of CSA of those nerves was followed longitudinally in CIDP. The median (range) CSA of the vagus nerve was 2 (1-28) mm2 in CIDP, 3 (2-6) mm2 in CMT1A, and 1 (1-2) mm2 in HC. The vagus nerve CSA was positively correlated with the maximum CSA of median/ulnar nerve in CIDP and CMT1A. The alteration in vagus nerve CSA was positively correlated with the alteration in mean median/ulnar nerve CSA in CIDP during follow-up. The vagus nerve was involved to a similar extent as the median and ulnar nerves in CIDP and CMT1A, although no symptoms or signs of vagus nerve involvement were found. Further study should be performed to explore the clinical relevance of vagus nerve enlargement in these disorders.

MRI appearance of jogger's foot.

To characterize the MRI findings present in patients with clinically proven or suspected jogger's foot. Ten years of medical charts in patients clinically suspected of having jogger's foot and who had MRI studies completed were identified utilizing a computer database search. Six study cases were identified. The MRI examinations of the study cases and an age- and gender-matched control group were reviewed in a blinded fashion by two musculoskeletal radiologists. Size and signal intensity of the medial plantar nerve were measured and characterized. The medial foot musculature was assessed for acute or chronic denervation changes. The medial plantar nerve was found to have moderately increased T2 signal compared with normal skeletal muscle in 3/6 study group cases and markedly increased T2 signal in the remaining 3/6 cases. In all control cases, the nerve was reported to have T2 signal equal or minimally higher than normal skeletal muscle. The mean total size of the medial plantar nerve was significantly larger in the study group when compared with that in the control group at all measured locations (p < 0.04). Abnormal thickness and T2 hyperintensity of the medial plantar nerve centered at the master knot of Henry are characteristic MRI findings in patients with jogger's foot when compared with control subjects. Muscular denervation changes may also be seen, most commonly in the flexor hallucis brevis muscle.

THU0477 SURAL NERVE SIZE IN FIBROMYALGIA SYNDROME

Background:The pathophysiology of fibromyalgia syndrome (FM) still needs to be fully clarified. In addition to the central sensitization mechanisms, some evidence suggests an involvement of the peripheral nervous system, mainly intended as small fibers neuropathy. The sural nerve showed some alterations, in terms of increasead cross-sectional area (CSA), in the course of small fibers neuropathy.Objectives:To evaluate sural nerve CSA and factors associated with increased CSA in FM patients.Methods:A cross sectional evaluation was conducted in consecutive FM patients according to the 2016 American College of Rheumatology criteria. Demographic, clinimetric parameters (in particular the revised Fibromyalgia Impact Questionnaire [FIQR] to assess the severity of the disease and the PainDetect Questionnaire [PDQ] to evaluate neuropathic pain features) and the sural nerve dimensions measured by ultrasound were recorded for each patient. The size of the sural nerve was described in terms of the mean cross-sectional area (CSA) measured bilaterally. CSA was measured at the leg level, 14 cm from the apex of the lateral malleolus, where the sural nerve is detectable as a structure adjacent to the small saphenous vein in the distal portion of the leg. The ultrasound examination was performed with a MyLab Class C (Esaote S.p.A., Genoa, Italy) equipped with a 6-18 MHz multifrequency broad band probe. CSA was compared with demographic and clinimetric parameters through one-way analysis of variance (ANOVA). A multiple regression was also conducted using CSA as dependent variable, with age, body mass index (BMI), disease duration, FIQR and PDQ as independent variables.Results:The study involved 110 FM patients (105 women and five men), with a mean age of 50.7 (±11.1) years and a mean disease duration of 5.8 (±5.2) years. Sural nerve CSA showed a statistically significant increase in patients with higher PDQ scores (p=0.0096) and, even more significantly, in overweight or obese subjects (p &lt;0.001). The multiple regression analysis, using CSA as dependent variable, confirmed that the PDQ score (p=0.0049) and the body mass index (p&lt;0.0001) are the only two independent variables associated with CSA size (Table 1).Table 1.Multiple regression analysis of the independent variables related to the mean cross-sectional area (dependent variable) of sural nerve.Indipendent variablesCoefficientStandard errortprpartialrsemipartialConstant-0.2551BMI0.075920.018474.1110.00010.37390.3462Disease duration-0.024920.02092-1.1910.2364-0.11600.1003Age0.0024550.0098330.2500.80330.024480.02103FIQR0.00013760.0068620.02010.98400.0019660.001689PDQ0.052720.019972.6390.00960.25060.2223Abbreviations: BMI=Body Mass Index; FIQR=revised Fibromyalgia Impact Questionnaire; PDQ=PainDetect QuestionnaireConclusion:Increased sural nerve CSA is associated with neuropathic like pain features and BMI. Overweight and obesity appear to be associated with an FM phenotype with greater peripheral involvement than normal-weight subjects. Sural nerve ultrasound, an easy to perform examination, could be a useful tool to identify this kind of patients.

Comparison of direct measurement of intracranial pressures and presumptive clinical and magnetic resonance imaging indicators of intracranial hypertension in dogs with brain tumors.

BackgroundIntracranial hypertension (ICH) is often presumptively diagnosed based on clinical or imaging findings. Clinical or imaging surrogates of ICH are not usually validated with reference standard direct intracranial pressure (dICP) recordings.HypothesesDogs with brain magnetic resonance imaging (MRI) or clinical features of presumed ICH would have higher dICP than dogs lacking those features.AnimalsTwenty dogs with gliomas and 3 normal controls.MethodsProspective, convenience study. Dogs were presumptively categorized with normal ICP or ICH from scores generated from described clinical and brain MRI indicators of ICH. dICP was recorded in anesthetized dogs using an intraparenchymal microsensor and compared between groups.ResultsdICP was not different between control (10.4 ± 2.1 mm Hg) and dogs with glioma (15.6 ± 8.3 mm Hg), or between dogs in clinically predicted ICP groups. Compared with dogs with MRI‐predicted normal ICP, MRI‐predicted ICH dogs had higher dICP (10.3 ± 4.1 versus 19.2 ± 7.9 mm Hg, P = .004), larger tumors (1.45 ± 1.2 versus 5.71 ± 3.03 cm3, P = .0004), larger optic nerve sheath diameters, and 14/14 (100%) displayed structural anatomical shifts on MRI. At a dICP threshold of 15 mm Hg, the sensitivity of MRI for predicting ICH was 90% and the specificity 69%.Conclusions and Clinical RelevancedICP measurements are feasible in dogs with brain tumors. MRI features including brain herniations, mass effect, and optic nerve size aid in the identification of dogs with ICH. Clinical estimation of ICP did not discriminate between dogs with and without ICH.

Normative Observational Nerve Ultrasound Values in School-Age Children and Adolescents and Their Application to Hereditary Neuropathies.

Backgrounds: We have aimed to establish nerve ultrasound reference data in 8 to 17-year-old children and adolescents and to compare those data to younger children, adults, and age-matched children with polyneuropathies.Methods: High-resolution ultrasounds of the nerves were performed in 117 healthy children and adolescents at 20 predefined landmarks in the neck and the extremities of both sides. Mean values, side-to-side differences and intraneural ratios, as well as upper limits have been calculated. In a second step, a comparison between 25 children and adolescents of the same age range with proven hereditary and acquired neuropathies and lysosomal storage diseases has been carried out.Results: Nerve growth correlates significantly with age and reaches adult values at the age of around 15 years. The influence of body mass index and gender is negligible at most segments. By the use of age-specific upper limits, nerve enlargement could be seen in distinct types of neuropathies, particularly in demyelinating hereditary and inflammatory types, which is comparable to findings in adults, but also in rare lysosomal storage diseases.Conclusion: Nerve size correlates with age during childhood and reaches a climax in younger adults. Age-matched reference data are inevitable to differ between hypertrophic and non-hypertrophic nerve damage, e.g., in neuropathies.

Single-sided deafness after sudden hearıng loss: late effect on cochlear nerve size.

Single-sided deafness (SSD) is a condition where an individual has non-functional hearing in one ear and receives no clinical benefit from amplification in that ear, with the contralateral ear possessing normal audiometric function. Cochlear implant presents a good choice in rehabilitation of SSD. The presence of a deficient cochlear nerve (CN) has been linked to poor performance with cochlear implants. CN can be measured by imaging techniques. The objective of this study was to compare CN diameter in patients who had a history of single-sided deafness because of sudden hearing loss. Retrospective study where radiologist was blind designed. 53 SSD patients who had a history of sudden hearing loss and MRI at least 5years after the sudden hearing loss were included in this retrospective study. High-resolution 3-D constructive interference in steady state (CISS)-sequence magnetic resonance (MRI) images was review by the neurotology-experienced blind radiologist. Vertical, horizontal and area measurements of cochlear nerve between the deaf and the normal ear were made. There was no statistically significant difference between the normal ear and deaf ear of the subjects in terms of cochlear nerve vertical diameter, horizontal diameter and area. (respectively, p = 0.250; p = 0.183; p = 0.874) CONCLUSION: The numbers of remaining cochlear neurons and spiral ganglion cells in the implanted deaf ears are critical and evidence was not found for spiral ganglion cell loss in the sudden hearing loss deaf ear with SSD in MRI. In the light of all these findings, implantation would be a good choice for rehabilitation in postlingual SSD regardless of auditory deprivation duration.

SPARC: A Road Map for Vagus Nerve Stimulation: Evidence of Vagotopy in a Swine Model

Cervical vagal nerve stimulation (VNS) is an FDA approved treatment for epilepsy and depression and is currently being evaluated for treatment of numerous other disorders including pain, anxiety, and inflammation. VNS also received European market approval for heart failure, bronchoconstriction, and diabetes; however, approval for these indications was based on studies in animals, such as dogs and rats, whose vagal nerve size may not have been representative of humans. When subjected to double‐blinded, randomized, sham controlled studies for subsequent U.S. approval, many of these CE‐marked VNS indications failed to meet their primary efficacy endpoints. More than 100,000 patients have undergone VNS, but despite the efficacy of vagal nerve stimulation in a subset of patients, many fail to reach stimulation levels that result in alleviation of symptoms without triggering unwanted side effects. Post hoc studies of the patient population suggested that VNS may not engage the intended fiber pathways in humans, despite engagement in preclinical studies in mouse, rat, or dog. Stimulation parameters were limited in these studies as higher parameters caused side effects such as cough, voice alteration, and dyspnea. Discrepancies between stimulation amplitude needed for intended effect versus unwanted side effect could be directly related to the relative size of the vagus nerve across animal models, variations in fascicle organization, or variations in branching patterns.To address translating improvements in VNS from the lab to the clinic, we evaluated the swine as a potential model for approximating the clinical environment. The size and fascicular organization of the swine vagus nerve is more representative of the human nerve than previously used models. We used a combination of histology, microdissection, and ultrasound to establish a distinct bimodal organization of groups of fascicles stemming from one large fascicle at the inferior (nodose) ganglion, an organization we have termed ‘vagotopy’. We demonstrated that with the use of ultrasound we can visualize the fascicular organization in vivo, an approach that could be used clinically to target stimulation of either sensory fibers or parasympathetic efferents, depending on therapeutic intent. These advances in a clinically relevant model not only inform electrode placement for target engagement, but provide an approach for reduction of side effects.Support or Funding InformationAcknowledgementsFunded by TL1TR002380 andThe Defense Advanced Research Projects Agency (DARPA) Biological Technologies Office (BTO) Targeted Neuroplasticity Training Program under the auspices of Doug Weber and Tristan McClure‐Begley through the Space and Naval Warfare Systems Command (SPAWAR) Systems Center with (SSC) Pacific grants no. N66001‐17‐2‐4010, and the NIH SPARC Program Award OT2 OD025340.

SPARC: Neural elements mediating side effects during cervical vagus nerve stimulation in the pig

Vagus nerve stimulation (VNS) is FDA‐approved and CE‐marked for a diverse set of conditions including epilepsy, depression, heart failure, and others. Despite widespread adoption and perceived efficacy, a post‐hoc analysis of patients treated for heart failure using VNS revealed that only 12% of patients showed stimulation evoked heart rate changes one‐year post‐implant. This finding is not unexpected given that A‐type nerve fibers have the lowest activation thresholds, and they innervate neck muscles, causing contractions that patients will not tolerate. Therefore, muscle responses at lower amplitudes may have prevented application of higher amplitudes required to achieve cardiac effects in clinical trials of VNS for heart failure. Understanding therapy‐limiting side effects to VNS and finding ways to mitigate them are critical for optimizing VNS for clinical therapies.We developed a swine model of VNS which closely approximates the size and fascicular organization of the cervical vagus nerve observed in humans. The clinical LivaNova stimulation electrode was used as advised by a practicing neurosurgeon. We hypothesized that neck muscle responses are mediated by somatic branches of the vagus nerve as opposed to direct electrical activation of the muscle fibers. Further, we hypothesized that stimulation evoked responses depend on the location of the stimulation electrode on the vagus nerve. We measured compound nerve action potentials using intrafascicular electrodes placed within the vagus to identify activation of different nerve fiber types by conduction velocity. The downstream effects of nerve fiber activation, i.e. changes in heart rate and neck muscle responses (EMG), were measured using an arterial catheter and intramuscular electrodes, respectively. We then used a neuromuscular junction blocking agent, as well as systematic transection of somatic vagus nerve branches, to specifically identify the pathways causing neck muscle contractions.Two pathways contributed to VNS‐evoked neck muscle responses: activation of nerve fibers in the recurrent laryngeal branch of the cervical vagus nerve at low amplitudes and in the superior laryngeal branch at higher amplitudes. Lesser activation of the superior laryngeal branch could be achieved by moving the stimulation electrode caudally down the length of the vagus. This work represents a step towards mitigating intolerable side effects of VNS, thereby allowing maximization of intended target engagement and therapeutic benefit.Support or Funding InformationThe Defense Advanced Research Projects Agency (DARPA) Biological Technologies Office (BTO) Targeted Neuroplasticity Training Program under the auspices of Doug Weber and Tristan McClure‐Begley through the Space and Naval Warfare Systems Command (SPAWAR) Systems Center with (SSC) Pacific grants no. N66001‐17‐2‐4010, and the NIH SPARC Program Award OT2 OD025340.

Functional vagotopy in the cervical vagus nerve of the domestic pig: implications for the study of vagus nerve stimulation

Objective. Given current clinical interest in vagus nerve stimulation (VNS), there are surprisingly few studies characterizing the anatomy of the vagus nerve in large animal models as it pertains to on-and off-target engagement of local fibers. We sought to address this gap by evaluating vagal anatomy in the pig, whose vagus nerve organization and size approximates the human vagus nerve. Approach. Here we combined microdissection, histology, and immunohistochemistry to provide data on key features across the cervical vagus nerve in a swine model, and compare our results to other animal models (mouse, rat, dog, non-human primate) and humans. Main results. In a swine model we quantified the nerve diameter, number and diameter of fascicles, and distance of fascicles from the epineural surface where stimulating electrodes are placed. We also characterized the relative locations of the superior and recurrent laryngeal branches of the vagus nerve that have been implicated in therapy limiting side effects with common electrode placement. We identified key variants across the cohort that may be important for VNS with respect to changing sympathetic/parasympathetic tone, such as cross-connections to the sympathetic trunk. We discovered that cell bodies of pseudo-unipolar cells aggregate together to form a very distinct grouping within the nodose ganglion. This distinct grouping gives rise to a larger number of smaller fascicles as one moves caudally down the vagus nerve. This often leads to a distinct bimodal organization, or ‘vagotopy’. This vagotopy was supported by immunohistochemistry where approximately half of the fascicles were immunoreactive for choline acetyltransferase, and reactive fascicles were generally grouped in one half of the nerve. Significance. The vagotopy observed via histology may be advantageous to exploit in design of electrodes/stimulation paradigms. We also placed our data in context of historic and recent histology spanning multiple models, thus providing a comprehensive resource to understand similarities and differences across species.

Fascia and soft tissues innervation in the human hip and their possible role in post-surgical pain.

Persistent symptoms, most commonly pain, may remain after otherwise successful hip replacement surgery. Innervation of fascia and soft tissues has become increasingly important in etiopathogenesis of pain, but the relative importance of the various anatomical structures in the hip region is still not known. Innervation of skin, superficial adipose tissue, superficial fascia, deep adipose tissue, deep fascia, muscles, capsule, capsule ligament, ligamentum teres, and tendon in the human hip from 11 patients and 2 cadavers were quantified by staining with anti-S100 antibody for myelin-forming Schwann cells, to obtain the percentage of antibody positivity, density and mean diameter of the nerve fibers. The skin was the most highly innervated (0.73% ± 0.37% of positive area in patients; 0.80% ± 0.28% in cadavers); the tendon was the least innervated (0.07% ± 0.01% in patients, 0.07% ± 0.007% in cadavers). The muscles (vasto-lateral and gluteus medius) were the second most innervated structure according the percentage (0.31% ± 0.13% in living humans, 0.30% ± 0.07% in cadavers), but with only a few nerves, with large diameters (mean diameter 36.4 ± 13.4 µm). Instead, the superficial fasciae showed 0.22% ± 0.06% and 0.26% ± 0.05% of positive areas in living humans and cadavers, respectively. Fasciae were invaded by networks of small nerve fibers, revealing a possible role in pain. The superficial fascia was the second most highly innervated tissue after the skin, with a density of 33.0 ± 2.5/cm2 , and a mean nerve sizes of 19.1 ± 7.2 µm. Lastly, the capsule turned out to be poorly innervated (0.09%), showing that its removal does not necessarily lead to painful consequences. Statement of clinical significance: Deeper knowledge about the innervation of the soft tissue in the human hip joint will enhance study and understanding of the best surgical procedures to follow during hip arthroplasty to reduce post-operative pain.

Recent advances in magnetic resonance imaging of optic neuritis

Optic neuritis is a common cause of vision loss, but it is difficult to visualize the lesion well via conventional magnetic resonance imaging due to its small size and oblique orientations of the optic nerves. Some advanced techniques have been introduced into clinical practice in recent decades. Herein we review recent advances in magnetic resonance imaging techniques that are useful in cases of optic neuritis.

Orbital MRI versus fundus photography in the diagnosis of optic nerve hypoplasia and prediction of vision

IntroductionIn patients with optic nerve hypoplasia (ONH), the visualisation of the optic disc can be challenging and the definitive diagnosis difficult to ascertain without fundus photography. The use of MRI...

&lt;p&gt;Direct OPTOS Nerve Size Determination of Prevalent Optic Nerve Hypoplasia in Alaska&lt;/p&gt;

BackgroundOptic nerve hypoplasia (ONH), one of the most common causes of pediatric blindness in developed countries, has been difficult to directly quantify. We sought to measure optic nerve size in Alaskan pediatric patients with optic nerve hypoplasia using ultra-widefield fundus imaging.MethodsAdult and pediatric patients underwent conventional ultra widefield fundus imaging (OPTOS, Dunfermline, Scotland) with manual image processing to determine optic nerve size validated against refractive error and nystagmus and compared to optical spectral domain tomography. De-identified cases were then compared relative to visual acuity and birth prevalence.ResultsIn Alaska’s only pediatric ophthalmology outreach clinic, 108 cases of ONH less than 20 years old were clinically identified with 80 having ultra-widefield analysis. Median horizontal optic nerve diameter for 135 normals was 1.70 (95% C.I. 1.49, 2.14) whereas in patients clinically diagnosed with optic nerve hypoplasia was 1.23 (95% C.I 0.38, 1.45). Visual acuity (20/y) was related to horizontal optic nerve diameter (x) by y = 187 x-4.1. Horizontal nerve diameter h could be estimated from vertical nerve diameter v by h = 0.73v + 0.3 even in nystagmus patients. From 108 with ONH, 6 had threshold retinopathy of prematurity, 12 profound nystagmus, 32 legally blind, 6 with septo-optic dysplasia, and 5 with fetal alcohol syndrome. ONH is very prevalent in Alaska occurring at least 8–10 per 10,000 births.ConclusionCompared to vertical diameter, horizontal diameter was more distinctive of optic nerve hypoplasia and more perturbed by nystagmus. Both were independent of refractive error. When hand-held, spectral domain OCT is not convenient, ultra-widefield fundus analysis is recommended for direct estimation of optic nerve size in children and adults. Optic nerve hypoplasia is prevalent in Alaskan children.

Morphometric evaluation of trigeminal nerve and meckel cave with 3.0 magnetic resonance imaging

Introduction: This study aimed to investigate morphometric features of the trigeminal nerve in healthy people on magnetic resonance images. The alterations in the size of the trigeminal nerve in the cisternal region along with aging and asymmetry between the right and left trigeminal nerves were also assessed. The knowledge of normal morphometric properties of the trigeminal nerve may be useful in evaluating patients having trigeminal neuralgia. Material and Methods: This retrospective study included 120 (62 males, 58 female) healthy individuals over 20 years old who had no previous or current cranial pathology. According to age ranges, individuals were evaluated in four groups as 20–29 years, 30–39 years, 40–49 years, and 50 years and older. Besides the long- and short-axis lengths of the trigeminal nerve, long- and short-axis lengths of Meckel cave, as well as the trigeminal-pons angle, were measured using three-dimensional balance fast-field echo sequence with 3T magnetic resonance imaging on the right and left sides.Results: It was observed that the lengths of trigeminal nerve were shorter on the right side in comparison to the left side (mean long axis 0,79 ± 0,20 cm on the right, 0,86 ± 0,28 cm on the left, P

SSBP1 mutations cause mtDNA depletion underlying a complex optic atrophy disorder.

Inherited optic neuropathies include complex phenotypes, mostly driven by mitochondrial dysfunction. We report an optic atrophy spectrum disorder, including retinal macular dystrophy and kidney insufficiency leading to transplantation, associated with mitochondrial DNA (mtDNA) depletion without accumulation of multiple deletions. By whole-exome sequencing, we identified mutations affecting the mitochondrial single-strand binding protein (SSBP1) in 4 families with dominant and 1 with recessive inheritance. We show that SSBP1 mutations in patient-derived fibroblasts variably affect the amount of SSBP1 protein and alter multimer formation, but not the binding to ssDNA. SSBP1 mutations impaired mtDNA, nucleoids, and 7S-DNA amounts as well as mtDNA replication, affecting replisome machinery. The variable mtDNA depletion in cells was reflected in severity of mitochondrial dysfunction, including respiratory efficiency, OXPHOS subunits, and complex amount and assembly. mtDNA depletion and cytochrome c oxidase-negative cells were found ex vivo in biopsies of affected tissues, such as kidney and skeletal muscle. Reduced efficiency of mtDNA replication was also reproduced in vitro, confirming the pathogenic mechanism. Furthermore, ssbp1 suppression in zebrafish induced signs of nephropathy and reduced optic nerve size, the latter phenotype complemented by WT mRNA but not by SSBP1 mutant transcripts. This previously unrecognized disease of mtDNA maintenance implicates SSBP1 mutations as a cause of human pathology.

Artificial nerve conduit in the repair of recurrent laryngeal nerve injury

Recurrent laryngeal nerve (RLN) injury is one of the most common and serious complications of cervical and thoracic surgery, which can occur due to neoplastic or iatrogenic factors. End-to-end anastomosis will be performed for a short rupture, however, reconstruction of a long defect remains a challenge. Autologous nerve transplantation is limited due to limited source of donor nerves. The loss of sensory and functional function in the innervation region and the mismatch of the structure and size of the recipient nerve are also the problems. Nowadays, with the development of regenerative medicine and tissue engineering, artificial nerve conduits are expected to solve the above issues. The nerve conduit provides support for the regeneration of the broken axons, and can absorb neurotrophic factors and Schwann cells to provide a microenvironment for nerve regeneration. This article reviews and summarizes the published literature for different nerve conduits used to repair the RLN. The advantage and disadvantages are evaluated, and the future is prospected. Key words: Thyroidectomy; Recurrent laryngeal nerve injury; Vocal cord paralysis; Nerve conduit; Nerve regeneration