Branch Of Nerve Research Articles

Sihler's staining of the anterior belly of digastric muscle for botulinum toxin injection.

The anterior belly of the digastric muscle (ABDM) is the target of botulinum toxin injection; however, anatomical considerations related to the injection point are absent. This study used Sihler's staining to analyze the intramuscular nerve distribution of ABDM to identify the most effective botulinum toxin injection points. We used 12 specimens from 6 embalmed cadavers in this study. The specimens were manually dissected to preserve the mylohyoid nerve and subjected to Sihler's staining. From the gnathion to and hyoid bone, the ABDM was divided into three equal parts, distinguishing the anterior, middle, and posterior thirds. Only a branch of the mylohyoid nerve entered the ABDM, and its entry point was located in the middle-third region in all cases. The nerve endings were concentrated in the middle third (100%), followed by the anterior third (58.3%) and were not observed in the posterior third. The landmarks used in this study (gnathion and hyoid bone) are easily palpable on the skin surface, allowing clinicians to target the most effective injection site (middle third of ABDM). These results provide scientific and anatomic evidence for injection points, and will aid in the management of ABDM injection procedures in clinical practice.

Elp1 function in placode-derived neurons is critical for proper trigeminal ganglion development.

The trigeminal nerve is the largest cranial nerve and functions in somatosensation. Cell bodies of this nerve are positioned in the trigeminal ganglion, which arises from the coalescence of neural crest and placode cells. While this dual cellular origin has been known for decades, the molecular mechanisms controlling trigeminal ganglion development remain obscure. We performed RNAsequencing on the forming chick trigeminal ganglion and identified Elongator acetyltransferase complex subunit 1 ( Elp1 ) for further study. Mutations in ELP1 cause familial dysautonomia (FD), a fatal disorder characterized by the presence of smaller trigeminal nerves and sensory deficits. While Elp1 has established roles in neurogenesis, its functions in placode cells during trigeminal gangliogenesis have not been investigated. To this end, we used morpholinos to deplete Elp1 from chick trigeminal placode cells. Elp1 knockdown decreased trigeminal ganglion size and led to aberrant innervation of the eye by placode-derived neurons. Trigeminal nerve branches exhibited fewer axons, and abnormal interactions between placode-derived neurons and neural crest cells were observed. These findings reveal a new role for Elp1 in chick placode-derived neurons during trigeminal ganglion development. These results have potential high significance to provide new insights into trigeminal ganglion development and the etiology of FD. Elp1 is expressed in undifferentiated neural crest cells and placode-derived neurons contributing to the trigeminal ganglion.Elp1 knockdown in trigeminal placode cells reduces trigeminal ganglion size.Elp1 depletion from trigeminal placode cells leads to aberrant target tissue innervation and disrupts proper neural crest-placodal neuron interactions in the trigeminal ganglion. NIH R01DE024217 and NIH R03HD108480.

Prognostic efficiency of diagnostic blockade as a method of modeling the result of selective neurotomy of the motor branches of the median nerve in patients with cerebral palsy

BACKGROUND: A feature of the disease course in patients with spastic cerebral palsy is a combination of motor neurological disorders with contractures in extremity joints. Neurosurgical methods are currently the main treatment for correcting the pathological tone of the “spastic hand.” However, the decreased tone does not affect secondary (fixed) contractures; therefore, the effectiveness of this type of treatment is extremely dependent on the accurate selection of a certain category of patients. Presumably, diagnostic blockade of the median nerve can create a reversible model for planned neurosurgical treatment. The inclusion of this technique as a standard for examining a patient with spastic cerebral palsy before invasive tone-lowering treatment can radically promote treatment effectiveness. AIM: This study aimed to assess the prognostic effectiveness of diagnostic blockade as a method of modeling the result of selective neurotomy of the motor branches of the median nerve in patients with cerebral palsy. MATERIALS AND METHODS: A longitudinal prospective study enrolled 39 children (aged 5–18 years) with spastic cerebral palsy. Before neurosurgical treatment, each patient underwent a diagnostic n. medianus under electrical stimulation and ultrasound control. After a diagnostic blockade, only patients who had a good functional and goniometric response were selected for the study, which served as an indication for selective neurotomy of the median nerve, and orthopedic treatment was performed in children with a negative event. Patients referred for neurotomy underwent a standardized examination before treatment during the diagnostic blockade and after neurosurgical treatment. The examination included the assessment of the amplitude of passive and active movements in the joints of the upper extremities, muscle tone, and functional capabilities of the upper extremities and dynamometry. RESULTS: In comparison with the initial data, a significant increase in the amplitude of passive and active hand extension, passive and active abduction of the first finger, and upper limb functional capabilities according to the MACS classification and the Miller scale was determined both after the diagnostic blockade and after selective neurotomy of the motor branches of the median nerve. CONCLUSIONS: Based on the results of the study, the effect of the diagnostic blockade and neurosurgical treatment outcomes are unidirectional, which allows the use of blockade as a method for modeling the possible result in clinically complex cases of spastic hand. The use of diagnostic blockade in clinical practice makes it possible to adequately assess the severity of fixed contractures and reduce the pathological hypertonicity of the target muscles. Diagnostic blockade allows for the collection of sufficient information to make an objective decision about which type of treatment is most preferable for each patient – neurosurgical, orthopedic, or sequential use of both methods.

Diffusion-tensor magnetic resonance imaging in patients with consequences of obstetric brachial plexus palsy

BACKGROUND: Diffusion-tensor magnetic resonance imaging allows visualizing the conductive pathways of the brain and spinal cord and assessing their structure and integrity and has found wide application in practical medicine. Currently, brachial plexus diffusion-tensor magnetic resonance imaging is not a routine research technique, and very few studies have described its use in children and adolescents. AIM: This study aimed to evaluate the possibility of brachial plexus diffusion-tensor magnetic resonance imaging application in pediatric patients with obstetric brachial plexus palsy sequelae and identify correlations between the diffusion-tensor magnetic resonance imaging parameters of brachial plexus and parameters of electrophysiological study of the upper extremities in these patients. MATERIALS AND METHODS: A complex examination of 50 patients was performed. The main group included 30 patients aged 6–17 years, with contractures and secondary deformities of the bones of the shoulder girdle and upper limbs caused by unilateral obstetric brachial plexus palsy. The control group included 20 patients aged 7–17 (10.1 ± 2.1) years without clinical signs, and anamnestic data indicated the presence of damage to the brachial plexus and peripheral nerves of the upper limbs. RESULTS: No significant differences in diffusion-tensor magnetic resonance imaging parameters of the right and left brachial plexus were found in the control group. Significant differences in fractional anisotropy of the C5–C8 tracts on the side of the damaged brachial plexus were detected compared with those on the side of the undamaged brachial plexus. On the side of the injured brachial plexus, nonlinear correlations were found between the fractional anisotropy of the tracts of the spinal nerve and its branches and the amplitude of sensory responses from the sensory nerve, which originated from the anterior branches of this spinal nerve, and between the volume of the branches of the tracts of the spinal nerve and the amplitude of соmpound motor responses from the muscles, which were innervated by the anterior branches of this spinal nerve. CONCLUSIONS: Diffusion-tensor magnetic resonance imaging allows for the evaluation of the structural changes in the SNs that participate in the formation of the brachial plexus. The results can be used for further studies of diffusion-tensor magnetic resonance imaging of brachial plexuses in various pathologies in pediatric patients.

Anatomical assessments of injectate spread stratified by the volume of the intertransverse process block at the T2 level

BackgroundThis cadaveric study aimed to analyze injectate spread to target nerves during a single-injection, ultrasound-guided intertransverse process block.MethodsAn ultrasound-guided intertransverse process block with three different injectate volumes was administered to...

Tear Fluid Progranulin as a Noninvasive Biomarker for the Monitoring of Corneal Innervation Changes in Patients With Type 2 Diabetes Mellitus.

This study aimed to investigate the expression levels of progranulin (PGRN) in the tears of patients with diabetic retinopathy (DR) versus healthy controls. Additionally, we sought to explore the correlation between PGRN levels and the severity of ocular surface complications in patients with diabetes. In this prospective, single-visit, cross-sectional study, patients with DR (n = 48) and age-matched healthy controls (n = 22) were included and underwent dry eye examinations. Tear fluid was collected, and its components were analyzed using the Luminex assay. The subbasal nerve plexus of all participants was evaluated by in vivo confocal microscopy. Patients with DR exhibited more severe dry eye symptoms, along with a reduction in nerve fiber density, length, and branch density within the subbasal nerve plexus, accompanied by an increase in the number of dendritic cells. Tear PGRN levels were also significantly lower in patients with diabetes than in normal controls, and the levels of some inflammatory factors (TNF-α, IL-6, and MMP-9) were higher in patients with DR. Remarkably, the PGRN level significantly correlated with nerve fiber density (R = 0.48, P < 0.001), nerve fiber length (R = 0.65, P < 0.001), and nerve branch density (R = 0.69, P < 0.001). Tear PGRN levels might reflect morphological changes in the corneal nerve plexus under diabetic conditions, suggesting that PGRN itself is a reliable indicator for predicting the advancement of neurotrophic keratopathy in patients with diabetes. PGRN insufficiency on the ocular surface under diabetic conditions was found to be closely associated with nerve impairment, providing a novel perspective to discover the pathogenesis of diabetic complications, which could help in developing innovative therapeutic strategies.

Direct and Safe Approach in the Treatment of Subcondylar Fractures

Jaw fractures are a major cause of functional disability and social and cosmetic morbidity. Despite the high incidence of subcondylar fractures, their treatment remains controversial. In recent years and hand in hand with a refinement of surgical techniques and osteosynthesis, the focus has shifted to surgery. An optimal approach is one that allows the surgeon to perform an anatomical reduction under direct vision to avoid damage to facial nerve branches due to manipulation of the fragments or the approach per se and ultimately, that the scar is aesthetically acceptable. The aim of this paper is to offer a direct and safe approach, through the study of the technique in cadavers. A safe approach was found in most cases through incisions 13 mm from the preauricular line, as well as incisions with a length of 20 mm.

Long-Term Stimulation of the Left Dorsal Branch of the Thoracic Nerve Improves Ventricular Electrical Remodeling in a Canine Model of Chronic Myocardial Infarction.

To evaluate the ventricular electrophysiologic effects of long-term stimulation of the left dorsal branch of thoracic nerve (LDTN) derived from the left stellate ganglion (LSG) in a canine model of chronic myocardial infarction (MI). Seventeen adult male beagles were randomly divided into three groups: the sham group (sham operated, n = 6), the MI group (n = 6), and the MI + LDTN group (MI plus LDTN stimulation, n = 5). The canine model of chronic MI was induced by the occlusion of the left anterior descending artery (LADO). The LDTN was separated and intermittently stimulated immediately after LADO for 2months. The heart rate variability (HRV) analysis, in vivo electrophysiology, the evaluation of LSG function and neural activity, histological staining, and western blotting (WB) assay were performed to evaluate the effect of LDTN stimulation on the heart. The canine MI model was successfully established by LADO, and the LDTN was separated and stimulated immediately after LADO. The HRV analysis showed that LDTN stimulation reversed the increased LF value and LF/HF ratio of the MI group. LDTN stimulation prolonged the shortening ERP and APD90, decreased the dispersion of ERP and APD90, and increased the VFT. Additionally, LDTN stimulation inhibits the LSG function and neural activity. Furthermore, LDTN stimulation suppressed the activation of Wnt/β-catenin signaling, which contributed to the LSG neuronal apoptosis by upregulation of pro-apoptotic Bax and downregulation of anti-apoptotic Bcl-2. LDTN stimulation could attenuate cardiac sympathetic remodeling and improve ventricular electrical remodeling, which may be mediated by suppressing the activated Wnt/β-catenin signaling pathway and then promoting the LSG neuronal apoptosis.

Eczematous dermatitis of knees after bilateral total knee replacement: A rare cause.

SKINTED (Surgery of the knee, injury to the infrapatellar branch of the saphenous nerve, traumatic eczematous dermatitis) is a form of denervation dermatitis that occurs after total knee replacement (TKR). It is characterised by a delayed onset, localisation lateral to the surgical scar and associated hypoaesthesia. It is important to distinguish SKINTED from hypersensitivity to the implant which can also cause delayed eczematous reactions near the implant site. SKINTED has a good prognosis with resolution in a few months, while hypersensitivity to implant material has been associated with persistent eczema, systemic contact dermatitis and implant failure.

3D directional tuning in the orofacial sensorimotor cortex during natural feeding and drinking.

Directional tongue movements are essential for vital behaviors, such as feeding and speech, to position food for chewing and swallowing safely and to position the tongue for accurate sound production. While directional tuning has been well-studied in the arm region of the sensorimotor cortex during reaching tasks, little is known about how 3D tongue direction is encoded in the orofacial region during natural behaviors. Understanding how tongue direction is represented in the brain has important implications for improving rehabilitation for people with orolingual dysfunctions. The goal of this study is to investigate how 3D direction of tongue movement is encoded in the orofacial sensorimotor cortex (OSMCx) during feeding and drinking, and how this process is affected by the loss of oral sensation. Using biplanar video-radiography to track implanted markers in the tongue of behaving non-human primates (Macaca mulatta), 3D positional data was recorded simultaneously with spiking activity in primary motor (MIo) and somatosensory (SIo) areas of the orofacial cortex using chronically implanted microelectrode arrays. In some sessions, tasks were preceded by bilateral nerve block injections to the sensory branches of the trigeminal nerve. Modulation to the 3D tongue direction was found in a majority of MIo but not SIo neurons during feeding, while the majority of neurons in both areas were modulated to the direction of tongue protrusion during drinking. Following sensory loss, the proportion of directionally tuned neurons decreased and shifts in the distribution of preferred direction were observed in OSMCx neurons. Overall, we show that 3D directional tuning of MIo and SIo to tongue movements varies with behavioral tasks and availability of sensory information.

Use of a Monopolar Stimulator to Preserve the Frontotemporal Branches of the Facial Nerve During a Pterional Approach: 2-Dimensional Operative Video.

Preservation of the frontotemporal branches of the facial nerve is essential to obtain good cosmetic outcomes after anterolateral cranial base approaches.1,2 Since the description of the interfacial dissection, most nerve injuries are due to retraction of the nerve fibers and not direct transection.3-5 In this video, we showcase the use of a monopolar stimulator to guide the placement of hook retractors and assess no undue retraction is applied to the nerve fibers during a pterional craniotomy. This simple tool can help in preserving frontalis function after anterolateral skull base craniotomies. Institutional review board approval was not required; the patient consented to the procedure and to the publication of his/her image.

Sustained corneal nerve loss predicts the development of diabetic neuropathy in type 2 diabetes.

This study was undertaken to investigate whether sustained rather than a single measure of corneal nerve loss was associated with the onset of diabetic peripheral neuropathy (DPN) and the progression of neuropathic symptoms and deficits in individuals with type 2 diabetes (T2D). Participants underwent clinical, metabolic testing and assessment of neuropathic symptoms, vibration perception threshold (VPT), sudomotor function, and corneal confocal microscopy (CCM) at baseline, 1, 2, and 4-7 years. Sustained corneal nerve loss was defined as abnormal corneal nerve fiber density (CNFD, <24 fibers/mm2), corneal nerve branch density (CNBD, <21 branches/mm2), and corneal nerve fiber length (CNFL, <16 mm/mm2) persisting for ≥50% of the study duration. A total of 107 participants with a mean duration of T2D of 13.3 ± 7.3 years, aged 54.8 ± 8.5 years, underwent baseline and follow-up assessments over a median duration of 4 years, ranging from 1 to 7 years. The DPN prevalence at baseline was 18/107 (16.8%), and of the 89 participants without DPN at baseline, 13 (14.6%) developed DPN during follow-up. Approximately half of the cohort had sustained corneal nerve damage, and corneal nerve measures were significantly lower in this group than those without sustained damage (p < 0.0001). Sustained corneal nerve damage was associated with the development of DPN (p < 0.0001), a progressive loss of vibration perception (p ≤ 0.05), an increased incidence of burning pain, numbness, or a combination of both (p = 0.01-0.001), and a borderline association with progressive sudomotor dysfunction (p = 0.07). Sustained abnormal CNFL effectively distinguished between participants who developed DPN and those who did not (AUC: 76.3, 95% CI: 65.9-86.8%, p < 0.0001), while baseline and other sustained measures did not predict DPN onset. Sustained abnormal CCM is associated with more severe corneal nerve damage, DPN development, and the progression of neuropathic symptoms and deficits. Regular CCM monitoring may enable the identification of those at greater risk of developing and worsening DPN who may benefit from more aggressive risk factor reduction.

Right vagotomy alters heart rate variability temporarily and increases total choline levels in rats

Abstract Objectives The variability in the time intervals between heartbeats, known as heart rate variability (HRV), serves as a reflection of the intricate interplay between the sympathetic and parasympathetic neural systems. While the potential asymmetric effects of the left and right branches of the vagus nerve remain uncertain, this study aims to investigate the impact of unilateral, bilateral, and atropine interventions on HRV parameters and choline levels within cardiac tissue. Methods 40 male adult Wistar albino rats were randomly assigned to the five groups (each n=8): sham-operated, atropine, right vagotomy, left vagotomy, and bilateral vagotomy. Heart rate variability (HRV) analyses were conducted, and the levels of total choline/acetylcholine in heart tissues were quantified. Statistical analyses were performed to assess the results. Results The bilateral vagotomy and atropine groups exhibited higher heart rates and high frequency power (HF), along with reduced low frequency power (LF). Total power (TP) remained relatively unchanged. In the bilateral vagotomy group, DFAα1 was significantly elevated while DFAα2 was reduced significantly. SD1 and SampEn were significantly lower in both the bilateral vagotomy and atropine groups. Notably, the right vagotomy group displayed significant changes primarily in the 15th minute, particularly in time-domain parameters, HF, TP, and SD1, with a significant increase observed in total choline levels. Conclusions Our results revealed that asymmetrical vagal innervation induces distinct effects on heart rate variability parameters and total choline/acetylcholine levels in heart tissues. Our findings suggest that compensatory hemodynamic recovery, possibly driven by contralateral vagal overactivity, may contribute to these observed results.

A Characteristic Magnetic Resonance Imaging Finding to Identify Morton Neuroma: The Slug Sign.

Morton neuroma is a common cause of forefoot pain and sensory disturbances, but it is difficult to identify on magnetic resonance imaging (MRI). The aim of this study was to verify the usefulness of a characteristic MRI finding (slug sign) for identifying Morton neuroma and to clarify the relationship between excised neuroma characteristics and preoperative MRI findings. Twenty-two web spaces were retrospectively assessed from the second and third intermetatarsal spaces of 11 feet of 10 patients (7 women and 3 men, aged average 59.5 years) who underwent surgical excision of Morton neuroma between 2017 and 2022. Asymptomatic web spaces were used as control. Neuromas with 2 branches of the plantar digital nerves on axial T1-weighted MRI (MRI-T1WI) were considered the slug sign. We investigated the preoperative presence of the slug sign in Morton neuroma and asymptomatic control web spaces. We also investigated the relationship between the maximum transverse diameter of the excised specimen and that estimated on coronal MRI-T1WI. A total of 15 Morton neuromas were excised and assessed. The slug signs were present in 10 intermetatarsal spaces in 15 web spaces with Morton neuroma whereas the sign was found in 1 intermetatarsal space in 7 asymptomatic web spaces. The sensitivity and specificity for the slug sign to diagnose Morton neuroma was 66.7% and 85.7%, respectively. The positive and negative predictive values were 90.9% and 54.5%, respectively. The mean maximum transverse diameter of excised neuromas was 4.7 mm. The mean maximum transverse diameter of neuromas on coronal MRI-T1WI was 3.4 mm. A significant positive correlation was found between the maximum transverse diameters of excised specimens and diameters estimated on coronal MRI-T1WI (r = 0.799, P < .001). The slug sign may be a useful indicator of Morton neuroma on MRI to confirm nerve involvement after bifurcation. Level IV, retrospective series.

Study on the consistency between CBCT image features of sphenopalatine foramen and those seen in nasal endoscopy

Objective:To study the clinical anatomy of the sphenopalatine foramina by dissecting the sphenopalatine foramina during Vidian nerve branch neurotomy. The anatomy and CBCT images of sphenopalatine foramen were analyzed to facilitate the navigational of clinical operation using CBCT images. Methods:From October 2017 to September 2023, 84 cases（168 sides） of Vidian nerve branch neurotomy in our department were collected. The clinical summary was made according to the anatomy of sphenopalatine foramen during the operation. Preoperative CBCT imaging findings of the sphenopalatine foramina were also studied. Results:The clinical anatomy of sphenopalatine foramen could be divided into four types: middle meatus type（1.19%）, trans-meatus type（62.29%）, superior meatus type（33.33%） and double foramen type（1.19%）. The incidence of ethmoidal ridge was 98.81%. The distance from sphenopalatine foramina to posterior nasal canal were（14.63±2.66） mm to left and（14.65±2.63） mm to right, The position Angle ∠a of lower margin of sphenopalatine foramina were（62.36±10.05）° to left and（61.51±11.82）° to right, respectively. Axial CT images can be used to divide the sphenopalatine foramen into five levels: the upper edge of the sphenopalatine foramen level, the Vidian nerve level, the basal plate interaction level, the lower edge of the sphenopalatine foramen level and the pterygopalatine canal level. The agreement between endoscopic anatomy of sphenopalatine foramen and imaging navigation was 100%. Conclusion:The sphenopalatine foramina exhibit various anatomical types. The preoperative navigational CBCT reading can effectively identify the type of sphenopalatine foramina, guide the choice of surgical method, and help avoid serious complications. This has significant clinical application value.

The choice of method of electroneuromyogaphy in remote consequences of gunshot and mine-blast injuries of limb nerves

Objective. Clarification of the nature of damage and degree of functional disorders in the remote consequences of gunshot and mine-blast injuries of limb nerves using neurophysiological techniques (NP) of functional diagnostics (stimulation and needle electromyography), correlation of these data with the nerve damage characteristics determined during surgical interventions (operative findings). Materials and methods. 480 military personnel and civilians, men aged 18-64 years (average age 33.5 years), with gunshot and mine-blast injuries of limb nerves (LNI) within 1 to 11 months after injury were examined. A total of 1400 EMG studies were conducted. Clinical-neurological methods were used to determine the level, degree, and nature of LNI. Results. Among the examined 480 patients, complete nerve damage was detected in 299, and partial in 181. Causes of nerve damage included: shrapnel, gunshot, mine-blast injuries, nerve rupture due to bone fractures, injuries by sharp objects, iatrogenic damage. In 62.3% of cases of complete LNI surgical interventions were performed using the technique of neurotization using branches of donor nerves. Provided anatomical integrity of nerve structures and presence of conductivity during EMG testing, external or internal neurolysis was performed. Surgical intervention timing: up to 6 months post-injury - 68.1% of cases; up to 3 months - 31.9%. Based on the results of comprehensive clinical-NP research, adapted schemes for assessing NP data corresponding to each pathohistological type of LNI were developed, and NP criteria for classifying consequences of LNI into three degrees of severity of functional deficit - mild, moderate, and severe were proposed. Conclusions. Criteria for choosing the optimal NP diagnostic methodology for the remote consequences of gunshot and mine-blast injuries of limb nerves have been determined. Comprehensive clinical-instrumental diagnostics allows to objectify the level and degree of limb nerve damage, signs of neuromuscular apparatus recovery, provides information for planning of the surgical tactics and subsequent rehabilitation therapy.

The importance of individualized and multiple landmarks for the identification of facial nerve trunk: a narrative review

The identification of the facial nerve trunk(FNT) is an important step in surgical procedures involving the parotid gland and adjacent structures to minimize the risk of inadvertent nerve damage which leads to facial muscle paralysis. Despite the availability of various anatomic landmarks such as the tragal pointer, posterior belly of digastric muscle, tympanomastoid suture, digastric branch of facial nerve and styloid process, no single landmark is perfect, with variations observed between individuals. Therefore, a comprehensive knowledge of facial nerve anatomy is essential for FNT identification. In this review, we tried to introduce clinically meaningful methods for the localization of facial nerve trunk. The preference of landmark could be changed by the major of the surgeon or the location of the tumor of the patients. Understanding the characteristics and drawbacks of the landmarks and choosing multiple landmarks that were convenient for surgeon would be necessary.

Predicting in vivo therapeutic efficacy of CelTrac1000-labeled hair follicle epidermal neural crest stem cells in models of repairing rat facial nerve defects via second near-infrared fluorescence imaging

AimsTo detect the therapeutic efficacy of CelTrac1000-labeled hair follicle epidermal neural crest stem cells (EPI-NCSCs) on repairing facial nerve defects by second near-infrared (NIR-II) fluorescence imaging. Materials and methodsFirstly, CelTrac1000-labeled EPI-NCSCs were microinjected into the acellular nerve allografts (ANAs) to bridge a 10-mm-long gap in the buccal branch of facial nerve in adult rats. Then, Celtrac1000-labeled EPI-NCSCs were detected by NIR-II fluorescence imaging system to visualize the behavior of the transplanted cells in vivo. Additionally, the effect of the transplanted EPI-NCSCs on repairing facial nerve defect was examined. Key findingsThrough 14 weeks of dynamic observation, the transplanted EPI-NCSCs survived in the ANAs in vivo after surgery. Meanwhile, the region of the NIR-II fluorescence signals was gradually limited to be consistent with the direction of the regenerative nerve segment. Furthermore, the results of functional and morphological analysis showed that the transplanted EPI-NCSCs could promote the recovery of facial paralysis and neural regeneration after injury. SignificanceOur research provides a novel way to track the transplanted cells in preclinical studies of cell therapy for facial paralysis, and demonstrates the therapeutic potential of EPI-NCSCs combined with ANAs in bridging rat facial nerve defects.

Co-existence of Neurotrophic Keratopathy in Eyes With Limbal Stem Cell Deficiency

PurposeTo investigate whether neurotrophic keratopathy is present in limbal stem cell deficiency (LSCD) by measuring corneal sensation and characterizing corneal subbasal nerve plexus. DesignProspective, cross-sectional “case-control” comparative study. MethodsForty-six eyes with LSCD and 14 normal eyes were recruited from 2019 to 2022. Corneal sensation was measured using a Cochet-Bonnet esthesiometer and subbasal nerve plexus was imaged using in vivo confocal microscopy (IVCM) at the central cornea and 4 limbal regions. Subbasal nerve density (SND, number of nerve/mm2), subbasal nerve length (SNL, total length of nerve/mm2) and subbasal nerve branch density (SNBD, number of branch/mm2) were quantified. LSCD was graded to stage 1, 2 and 3 using a previously established staging method` consisting of clinical scores, basal cell density, central corneal epithelial thickness and SNL. ResultsThe mean (±SD) cornea sensation in the central cornea and limbus were 29.2 ± 21.5 and 33.6 ± 15.1 mm in the LSCD group and 57.6 ± 5.8 and 54.3 ± 4.7 mm in the control group, respectively (all P < 0.001). In sectoral LSCD, the sensation in the affected regions (29.1 ± 17.6 mm) decreased significantly compared to the unaffected regions (41.4 ± 18.2 mm, P < 0.001). Central corneal SND, SNL and SNBD were reduced by 84.6%, 82.6%, and 89.2%, respectively in LSCD compared to the control (all P < 0.05). The central corneal sensation negatively correlated with the severity of LSCD (rho = -0.64, P < 0.0001) and positively correlated with SND, SNL, and SNBD (rho=0.63, 0.66, and 0.56, respectively; all P < 0.001). ConclusionsCorneal sensation was reduced in eyes with LSCD. The degree of corneal sensation reduction positively correlated with the severity of LSCD. This finding demonstrated the co-existence of neurotropic keratopathy in LSCD.

The relation of recurrent laryngeal nerve to inferior thyroid artery and extralaryngeal nerve branching may increase the risk of vocal cord paralysis in thyroidectomy

PurposeThe anatomical variations of the recurrent laryngeal nerve (RLN) are common during thyroidectomy. We aimed to evaluate the risk of RLN paralysis in case of its anatomical variations, retrospectively.MethodsThe patients with primary thyroidectomy between January 2016 and December 2019 were enrolled. The effect of age, gender, surgical intervention, neuromonitorisation type, central neck dissection, postoperative diagnosis, neck side, extralaryngeal branching, non-RLN, relation of RLN to inferior thyroid artery (ITA), grade of Zuckerkandl tubercle on vocal cord paralysis (VCP) were investigated.ResultsThis study enrolled 1070 neck sides. The extralaryngeal branching rate was 35.5%. 45.9% of RLNs were anterior and 44.5% were posterior to the ITA, and 9.6% were crossing between the branches of the ITA. The rate of total VCP was 4.8% (transient:4.5%, permanent: 0.3%). The rates of total and transient VCP were significantly higher in extralaryngeal branching nerves compared to nonbranching nerves (6.8% vs. 3.6%, p = 0.018; 6.8% vs. 3.2%, p = 0.006, respectively). Total VCP rates were 7.2%, 2.5%, and 2.9% in case of the RLN crossing anterior, posterior and between the branches of ITA, respectively (p = 0.003). The difference was also significant regarding the transient VCP rates (p = 0.004). Anterior crossing pattern increased the total and transient VCP rates 2.8 and 2.9 times, respectively.ConclusionRLN crossing ITA anteriorly and RLN branching are frequent anatomical variations increasing the risk of VCP in thyroidectomy that cannot be predicted preoperatively. This study is the first one reporting that the relationship between RLN and ITA increased the risk of VCP.