Superior Nerve Research Articles

A 3-in-1 RING block for the two superior genicular nerves and nerve to the vastus intermedius of the knee: A case report

A 3-in-1 RING block for the two superior genicular nerves and nerve to the vastus intermedius of the knee: A case report

A 25-Year Update on the Facial Nerve Sparing Approach for Vestibular Schwannoma.

This study updates the results of a facial nerve preservation approach to treating vestibular schwannomas at a single institution by a single surgeon using retrosigmoid craniectomy with microsurgery (MS) and gamma knife stereotactic radiosurgery (SRS) over a 25-year interval. We retrospectively reviewed 751 patients between 1998 and 2023 and grouped them by intervention: MS only (Group 1, 217 patients), SRS only (Group 2, 447 patients), MS then SRS (Group 3, 72 patients), SRS then MS (Group 4, 10 patients), and SRS then SRS (Group 5, 5 patients). The primary outcome variable was facial nerve function, defined as House-Brackmann grade ≤2 at last follow-up. Good outcomes by group were achieved in 98.2%, 99.6%, 93.1%, 90%, and 100% of patients, respectively. Upfront SRS (Group 2) resulted in significantly better facial nerve outcomes than upfront MS (Groups 1 and 3, 289 patients) (96.9% and 99.4%, P < 0.05). Mean tumor maximum linear diameters were 3.2, 1.32, 3.23, 1.98, and 1.64 cm. Subtotal resection rates in Groups 1, 3, and 4, were 68.2%, 81.9%, and 80%, respectively. The median (interquartile range) follow-up time among patients (minimum follow-up of 12 months) was 52 (26.75-88) months, with a maximum of 297 months (24.75 years). Overall, 98.1% of patients had a good facial nerve outcome with no operative mortality. For larger tumors, MS emphasizing facial nerve preservation over gross total resection followed by adjuvant SRS for any interval tumor regrowth yields excellent facial nerve outcomes and tumor control rates. For smaller tumors, upfront SRS achieves superior facial nerve preservation with MS and SRS both viable salvage options for treatment of tumor progression. This paradigm balances tumor control, facial nerve preservation, and low morbidity.

Efficacy of cold and cryo-preserved nerve allografts with low-dose FK506 for motor nerve regeneration: a preclinical study

BackgroundDespite their ability to regenerate as well as autografts, the use of nerve allografts is limited by the need for immunosuppression and the risk of disease transmission. Further, decellularized allografts lacking Schwann cells limit axonal regeneration in long nerve defects. This study evaluated sciatic nerve regeneration in rats implanted with cold- or cryopreserved allografts, and examined the effects of FK506, an immunosuppressant that targets calcineurin function, on motor recovery.MethodsSixty-five male Lewis rats were divided into five groups of 13, each with a 10-mm sciatic nerve gap. Group I received an autograft, whereas Groups II and III received allografts pretreated with cryopreservation and cold preservation, respectively. Groups IV and V were also implanted with cryo- and cold-preserved allografts, but were treated with a low dose of FK506. Motor regeneration was assessed at 20 weeks by the measurement of ankle contracture, compound muscle action potential, maximal isometric tetanic force, wet muscle weight of the tibialis anterior, peroneal nerve histomorphometry, and immunohistochemistry of the reconstructed sciatic nerve.ResultsSimilar motor recovery was observed between the autografts and both types of allografts. The groups treated with FK506 showed improved recovery, particularly in terms of ankle angle and tibialis anterior muscle weight. Histomorphometry revealed a superior myelinated fiber area and nerve ratio in the cold-preserved allograft group, while Group II displayed a less well-organized morphology.ConclusionThis study demonstrates that cold- or cryopreserved nerve allografts represent effective alternatives to autografts for peripheral nerve reconstruction, with low-dose FK506 enhancing motor recovery without necessitating immunosuppression.Level of Evidence IBasic Science Level I.

Short-Term Effects of Cooled Radiofrequency Ablation on Walking Ability in Japanese Patients with Knee Osteoarthritis.

Background/Objectives: Knee osteoarthritis (KOA) is a degenerative joint disease typically managed with conservative treatments, such as anti-inflammatory medications and intra-articular hyaluronic acid injections; however, advanced cases may eventually require surgical intervention. Recently, cooled radiofrequency ablation (CRFA) has emerged as a novel treatment option for alleviating KOA-related pain by temporarily disabling pain-transmitting nerves. This study evaluated the short-term effects of CRFA on pain relief and walking ability in KOA patients, with a specific focus on functional improvements in walking capacity. Methods: This study included 58 patients (71 knees) with KOA who underwent CRFA after experiencing inadequate pain control with conservative treatments. The cohort consisted of 28 men and 30 women, with a mean age of 75.2 years (55-90). Under ultrasound guidance, CRFA was performed on the superior lateral geniculate nerve, superior medial geniculate nerve, and inferior medial geniculate nerve, with each targeted nerve ablated. Pre- and post-procedural evaluations (one month after CRFA) included assessments of visual analog scale (VAS) scores for pain at rest and during walking, range of motion (ROM), knee extensor strength, walking speed, and gait stability. Results: Significant improvements in the mean VAS (rest/walking) and mean walking speed (comfortable/maximum) were observed following CRFA. However, no significant changes were noted in ROM, knee extensor strength, or walking stability. Conclusions: These findings suggest that rehabilitation may be essential to further enhance walking stability. Overall, CRFA appears to be a promising short-term treatment option for reducing VAS pain scores and enhancing walking speed in patients with KOA.

TIPS AND TRICKS IN SURGICAL TREATMENT OF LARGE VESTIBULAR SCHWANNOMAS

Vestibular schwannomas (VS) frequently referred to as acoustic neuromas are the most common tumours of the cerebellopontine angle. They are benign, generally slow-growing tumors that arise from the vestibular portion of the eighth cranial nerve. For patients with large vestibular schwannomas or those exhibiting symptoms from the tumor’s mass effect, surgical intervention remains the preferred treatment approach. This paper discusses the surgical management of patients with large vestibular schwannomas operated in our department and emphasizes the use of intraoperative monitoring for preserving facial nerve function. We review the key surgical steps and highlight the importance of preoperative planning, patient position, and the use of microsurgical techniques to optimize the surgical outcome. Gross total resection of large vestibular schwannomas is associated with worse facial nerve outcomes. Our preferred treatment strategy, especially for older patients, is planned subtotal resection followed by periodic imaging evaluation and radiotherapy in cases of documented tumor growth. This approach may lead to superior facial nerve preservation and improved quality of life for individuals with large vestibular schwannomas. Conclusion The optimal treatment approach for vestibular schwannoma remains a subject of debate. Gross total resection has traditionally been the gold standard for large tumors, but this is often accompanied by a higher risk of postoperative facial nerve dysfunction. Planned subtotal resection with the goal of preserving facial nerve function, followed by closed observation is an alternative approach.

Mesenteric blood flow and muscle sympathetic nerve activity during vasovagal syncope.

Vasovagal syncope is thought to be mediated by a progressive fall in cardiac output secondary to venous pooling of blood in the splanchnic circulation. How and when this occurs before syncope has not been determined. A total of 20 patients who became hypotensive during head-up tilt (age 40.9 ± 3.4 years; 10 females) were divided into two groups-the glyceryl trinitrate (GTN) group (n = 12) and the vasovagal syncope (VVS) group (n = 8) - on the basis of whether or not nitroglycerine provocation was required. They were compared with a control group (age 38.6 ± 3.3; 8 females; n = 13). Hemodynamics, including superior mesenteric artery blood flow (SMABF) and muscle sympathetic nerve activity (MSNA) were recorded continuously during early tilt, presyncope and recovery. We used pixel-weighting to calculate average velocity from the pulsed Doppler velocity envelope. During baseline and early tilt, resistance to mesenteric blood flow was lower in the VVS group: 0.30 ± 0.02 to 0.30 ± 0.02mmHg/ml/min versus controls 0.30 ± 0.03 to 0.38 ± 0.04mmHg/ml/min (p = 0.05). During presyncope, as blood pressure and stroke volume gradually fell, SMABF was higher in the VVS group, falling from 370 ± 46 to 248 ± 35ml/min, versus controls, falling from 342 ± 51 to 233 ± 19 (p = 0.03). At this time, MSNA was lower in the VVS group than controls: 39 ± 4 to 34 ± 3 bursts/min versus 45 ± 2 to 48 ± 3 (p = 0.001). During presyncope, increased splanchnic blood flow may pool more blood in capacitance vessels resulting in decreased venous return and cardiac output. This may be secondary to decreased vasoconstrictor sympathetic activity.

Effect of Active &amp; Passive Smoking on Macula &amp; Optic Nerve Using Optical Coherence Tomography Angiography (OCTA)

Abstract Background Smoking cause alterations in the retinal blood flow and damage of the blood retinal barrier, these retinal microvascular changes demonstrated by OCT-A may be an indicator of systemic microvascular changes. Objective The purpose of this study was to evaluate the effect of active and passive smoking on macula and optic nerve by measuring the macular thickness and microvasculature, GCC thickness, RNFL thickness and disc microvasculature using OCTA. Methods 150 healthy participants of 76 males and 74 females, divided in to three equal groups active smoker, passive smoker and control group. Optical coherence tomography angiography scanning was performed for all subjects. All macular subfields thickness, peripapillary retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) thickness, superficial and deep macular vessel density, foveal avascular zone (FAZ) area and radial peripapillary capillaries (RPC) density were measured and analyzed. Results Significant increase in the central macular thickness in the active and passive smoker, also there was significant decrease in the superior RNFL and deep parafoveal vessel density in the active and passive smoker, but no significant differences in GCC, FAZ, superficial capillary plexus(SCP) density, and radial peripapillary capillaries density between the three groups. Conclusion Active and passive smoking decrease deep parafoveal vessel density, superior retinal nerve fiber layer thickness, and increase central, inner and outer macular thickness in healthy middle age individuals.

Chronic Cough Related to Thyroid Cartilage Superior Cornu Abnormality.

Chronic cough is a common troublesome symptom in otolaryngology head and neck surgery practice. In rare cases, chronic cough may be related to anatomical abnormalities. In this article, we report the history of a 64-year-old female with a chronic course due to a curved superior cornu of the thyroid cartilage and related irritation of the laryngeal superior nerve. The cough was atypical and resolved after the surgical resection of the abnormal cornu. There was no recurrence at 9 months post-surgery. The findings of the present case report highlight the need to explore the laryngeal anatomy in patients with chronic cough to identify potential abnormalities, which may be treated surgically.

Effect of Metformin on Peripheral Nerve Morphology in Type 2 Diabetes: A Cross-Sectional Observational Study.

Diabetic peripheral neuropathy (DPN) affects around 50% of the 500 million people with type 2 diabetes worldwide and is considered disabling and irreversible. The present study was undertaken to assess the effect of metformin on peripheral neuropathy outcomes in type 2 diabetes. 69 type 2 diabetes participants receiving metformin were recruited and underwent clinical assessment, peripheral nerve ultrasound, nerve conduction studies and axonal excitability studies. 318 participants who were not on metformin were also concurrently screened, and 69 were selected as disease controls and matched to the metformin participants for age, sex, diabetes duration, BMI, HbA1c and use of other diabetes therapies. Medical record data over the previous 20 years were analysed for previous metformin use. Mean tibial nerve cross-sectional area (CSA) was lower in the metformin group (metformin 14.1 ∓ 0.7 mm2, non-metformin 16.2 ∓ 0.9mm2, p=0.038), accompanied by reduction in neuropathy symptom severity (p=0.021). Axonal excitability studies demonstrated superior axonal function in the metformin group and mathematical modelling demonstrated that these improvements were mediated by changes in nodal Na+ and K+ conductances. Metformin treatment is associated with superior nerve structure, clinical and neurophysiological measures. Treatment with metformin may be neuroprotective in DPN.

Dimensions of Arachnoid Bulk Ratio: A Superior Optic Nerve Sheath Index for Intracranial Pressure.

Background Discrepancies in the literature regarding optimal optic nerve sheath diameter (ONSD) cutoffs for intracranial pressure (ICP) necessitate alternative neuroimaging parameters to improve clinical management. Purpose To evaluate the diagnostic accuracy of the dimensions of the perineural subarachnoid space to the optic nerve sheath ratio, measured using US, in predicting increased ICP. Materials and Methods In a prospective cohort study from April 2022 to December 2023, patients with suspected increased ICP underwent optic nerve US to determine the dimensions of arachnoid bulk (DAB) ratio and ONSD before invasive ICP measurement. Correlation between the parameters and ICP, as well as diagnostic accuracy, was assessed using area under the receiver operating characteristic curve (AUC) analysis. Results A total of 30 participants were included (mean age, 39 years ± 14 [SD]; 24 female). The DAB ratio and ONSD were significantly larger in participants with increased ICP (38% [0.16 of 0.42] and 14% [0.82 of 6.04 mm], respectively; P < .001). The DAB ratio showed a stronger correlation with ICP than ONSD (rs = 0.87 [P < .001] vs rs = 0.61 [P < .001]). The DAB ratio and ONSD optimal cutoffs for increased ICP were 0.5 and 6.5 mm, respectively, and the ratio had higher sensitivity (100% vs 92%) and specificity (94% vs 83%) compared with ONSD. Moreover, the DAB ratio better predicted increased ICP than ONSD, with a higher AUC (0.98 [95% CI: 0.95, 1.00] vs 0.86 [95% CI: 0.71, 0.95], P = .047). Conclusion An imaging ratio was proposed to predict ICP based on the relative anatomy of the cerebrospinal fluid space, demonstrating more accurate diagnosis of increased ICP and a strong correlation with ICP values, suggesting its potential utility as a neuroimaging marker in clinical settings. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Shepherd in this issue.

Effectiveness of Radiofrequency Ablation of the Genicular Nerves of the Knee for the Management of Intractable Pain from Knee Osteoarthritis

BACKGROUND: The knee joint is one of the most common diseases in elderly individuals. This is a progressive and debilitating condition. The purpose of knee osteoarthritis treatment is to manage pain, increase mobility, and improve the quality of life. OBJECTIVES: This study evaluated the therapeutic effect of radiofrequency thermocoagulation (RFTC) on the genicular nerves in patients with intractable pain due to knee osteoarthritis, as well as its effects on pain severity and magnetic resonance imaging (MRI) findings. STUDY DESIGN: A prospective outcome study. SETTING: The outpatient clinic of a single academic medical center. METHODS: We conducted a prospective study. Fifty consecutive patients with intractable knee pain due to osteoarthritis were enrolled and underwent ultrasound (US)-guided RFTC of the genicular nerves (medial superior genicular nerve, medial inferior genicular nerve, and lateral superior genicular nerve). Pain severity was measured using the Numeric Rating Scale (NRS), and knee osteoarthritis-associated symptoms were evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at pretreatment and one, 3, and 6 months after RFTC treatment. We also analyzed the relationship between therapeutic outcomes and pain severity based on pre-treatment and knee MRI findings. RESULTS: No dropouts were observed. The most significant reduction in knee symptoms associated with knee osteoarthritis was observed after one month of treatment; however, at 3 and 6 months, there was a rebound effect, leading to a decrease in therapeutic efficacy. Nonetheless, there was still a noticeable decrease in symptoms due to knee osteoarthritis compared to those prior to RFTC treatment. The effect of RFTC treatment was better when pre-treatment pain was relatively less severe, knee effusion was not severe, there were no meniscal tears in the middle or posterior zones, no bone marrow edema in the middle and posterior zones of the femur and tibia, and no severe cartilage defects in the posterior femur and middle and posterior tibia. LIMITATIONS: We conducted our study without a control or a placebo group. CONCLUSION: RFTC of the genicular nerve is a good therapeutic option for controlling intractable pain following knee osteoarthritis. In addition, we found that a lower level of pain prior to treatment, along with the absence or lesser degree of knee joint effusion, as well as an absence or less severe middle or posterior knee pathologies associated with knee osteoarthritis, can predict a more favorable therapeutic outcome. KEY WORDS: knee, osteoarthritis, radiofrequency ablation, genicular nerve, pain, magnetic resonance imaging

Ocular toxicity of daily anti-tubercular treatment regimen: A prospective observational study

Context: India carries a significant burden of TB which is the commonest cause of infectious disease-related mortality. Anti-tubercular drugs can cause serious ocular toxic effects. Optical coherence tomography (OCT) can be used as a valuable tool in the quantitative analysis of anti-tubercular treatment (ATT)-induced toxic optic neuropathy. Aims: To study the changes in visual parameters in patients on ATT and to analyze the OCT changes in patients by taking measurements once before initiation of treatment and once during ongoing treatment (between three and six months). Settings and Design: Tertiary care center, Prospective observational study. Methods and Material: A prospective observational study was conducted in 140 eyes of 70 subjects undergoing ATT as per the latest RNTCP guidelines where the following determinants were examined, and the corresponding values were taken once before initiation of treatment and once during ongoing treatment (between three and six months) and results were analyzed. Around 90% of the subjects were examined at the end fourth month. Visual acuity was taken using the Log Mar chart, color vision using Ishihara’s chart, and slit lamp examination and fundus evaluation using a 90 D lens. OCT was done and average nasal, temporal, superior, and inferior quadrant retinal nerve fiber layer (RNFL) measurements were taken. Perimetry was also done; however, findings were not included in this study. Statistical Analysis Used: Frequency and percentage were applied to study the changes in visual parameters in patients on ATT. A paired t-test was applied for numerical variables to analyze the OCT changes in patients undergoing ATT. A P value &lt; 0.05 was considered statistically significant. Results: Despite a near-normal appearance of the fundus on ophthalmoscopy, OCT clearly demonstrated and quantified the loss of retinal nerve fibers. Statistically significant RNFL thinning (P value &lt; 0.001) was noted in the superior, temporal, and inferior quadrants and least in the nasal quadrant (P = 0.005). Significant deterioration in visual acuity was observed following three months of ATT (P = 0.001). Red-green color vision abnormalities were detected in 14 out of 140 eyes (10%). Conclusions: RNFL thickness was reduced on OCT. RNFL thickness quantification and assessment of other visual parameters especially color vision help in the early diagnosis of ocular toxic effects of ATT. Hence, awareness and active screening are imperative in preventing visual impairment and blindness.

Evaluation of Structural and Functional Retinal Changes in Children With Intermittent Exotropia Versus Healthy Children.

To detect structural and functional changes in children with intermittent exotropia using optical coherence tomography, pattern electroretinography (ERG), and multifocal ERG. The study included 26 patients with intermittent exotropia and 26 healthy individuals matched for age and sex with a mean age of 9.23 and 11.20 years in the intermittent exotropia and control groups, respectively (P = .310). All patients underwent full ophthalmic examination including measurement of the angle of strabismus at near and far, and assessment of the macula and optic nerve using optical coherence tomography, pattern ERG, and multifocal ERG. All patients had 6/6 best corrected visual acuity with no fixation preference. A significantly prolonged P and N wave latency was found in all measured rings of multifocal ERG of patients with intermittent exotropia, P wave amplitude was lower in rings 1 and 5, and N wave amplitude was lower in rings 1 and 2. Regarding pattern ERG, the amplitude of P50 wave was lower and N95 latency was prolonged in the intermittent exotropia group. The upper and lower ganglion cell complex and the superior retinal nerve fiber layer were significantly thinner in the intermittent exotropia group compared to controls. Children with intermittent exotropia without any associated amblyopia or refractive error showed a subnormal pattern and multifocal ERG response in addition to a thinner ganglion cell layer and retinal nerve fiber layer compared to normal controls. This signifies that subtle structural and functional retinal changes are found in patients with intermittent exotropia. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XXX-XXX.].

Continuous peripheral electrical nerve stimulation improves cardiac function via autonomic nerve regulation in MI rats

BackgroundPeripheral electrical nerve stimulation (PENS) reportedly improves cardiac function after myocardial ischemia (MI) by rebalancing the cardiac autonomic nervous system. The dynamic and continuous influence of PENS on autonomic and cardiac function based on cardiac self-repair is not well understood. ObjectivesThis study aimed to explore the relationship between autonomic nervous balance and functional cardiac repair after MI and to clarify the optimal acupoint selection and time course for PENS. MethodsThe activities of the superior cervical cardiac sympathetic nerve and vagus nerve were recorded to evaluate the autonomic tone directly. The pressure-volume loop system was used for left ventricular diastolic and systolic function. Noninvasive continuous electrocardiography and echocardiography were performed to analyze heart rate, heart rate variability, and left ventricular function. The effect of continuous PENS (cPENS) or instant PENS (iPENS) on autonomic and cardiac indications was tested. ResultsSympathetic nerve activity and vagus nerve activity increased as compensatory self-regulation on days 7 and 14 post-MI, followed by an imbalance of autonomic tone and cardiac dysfunction on day 28. cPENS at acupoint PC6 maintained autonomic hyperexcitability, improved myocardial systolic and diastolic abilities, and reduced myocardial fibrosis on day 28 post-MI, whereas cPENS at acupoint ST36 had a limited effect. Both iPENS at PC6 and ST36 improved the autonomic and cardiac function of rats in the cPENS groups. ConclusionRats showed autonomic fluctuations and cardiac dysfunction 28 days post-MI. cPENS produced sympathomimetic action to sustain cardiac self-compensation, but with acupoint specificity. On the basis of cPENS, iPENS evoked autonomic regulation and cardiac benefits without acupoint differentiation.

Reduced Graphene Oxide Fibers Combined with Electrical Stimulation Promote Peripheral Nerve Regeneration.

The treatment of long-gap peripheral nerve injury (PNI) is still a substantial clinical problem. Graphene-based scaffolds possess extracellular matrix (ECM) characteristic and can conduct electrical signals, therefore have been investigated for repairing PNI. Combined with electrical stimulation (ES), a well performance should be expected. We aimed to determine the effects of reduced graphene oxide fibers (rGOFs) combined with ES on PNI repair in vivo. rGOFs were prepared by one-step dimensionally confined hydrothermal strategy (DCH). Surface characteristics, chemical compositions, electrical and mechanical properties of the samples were characterized. The biocompatibility of the rGOFs were systematically explored both in vitro and in vivo. Total of 54 Sprague-Dawley (SD) rats were randomized into 6 experimental groups: a silicone conduit (S), S+ES, S+rGOFs-filled conduit (SGC), SGC+ES, nerve autograft, and sham groups for a 10-mm sciatic defect. Functional and histological recovery of the regenerated sciatic nerve at 12 weeks after surgery in each group of SD rats were evaluated. rGOFs exhibited aligned micro- and nano-channels with excellent mechanical and electrical properties. They are biocompatible in vitro and in vivo. All 6 groups exhibited PNI repair outcomes in view of neurological and morphological recovery. The SGC+ES group achieved similar therapeutic effects as nerve autograft group (P > 0.05), significantly outperformed other treatment groups. Immunohistochemical analysis showed that the expression of proteins related to axonalregeneration and angiogenesis were relatively higher in the SGC+ES. The rGOFs had good biocompatibility combined with excellent electrical and mechanical properties. Combined with ES, the rGOFs provided superior motor nerve recovery for a 10-mm nerve gap in a murine acute transection injury model, indicating its excellent repairing ability. That the similar therapeutic effects as autologous nerve transplantation make us believe this method is a promising way to treat peripheral nerve defects, which is expected to guide clinical practice in the future.

Late-onset of Labyrinthine Dysfunction in Chronic Brucella-induced Encephalitis

Brucellosis, caused by Brucella, dominates in the Middle East. Acute or chronic brucellosis can involve any organ system, and the involvement of the central nervous system leads to encephalitis, called neurobrucellosis (NB). We report a rare case from north India where a variant of Brucella caused NB led to progressive labyrinthine dysfunction; who developed vertigo, disequilibrium, and gradual progressive sensorineural (SN) hearing loss. Audiological tests pure-tone audiometry (PTA), otoacoustic emissions (OAE), stapedial muscle reflexes, auditory evoked brainstem responses (ABR), and vestibular evoked myogenic potentials (VEMPs) were conducted on the patients. PTA showed a bilateral profound SN hearing loss, an absent OAE, and ABR suggestive of cochlear dysfunction. The cervical and ocular VEMP showed delayed n1 and p1 latencies, suggesting superior and inferior nerve branch involvement. Vertigo or disequilibrium and SN hearing loss can be the late-onset manifestations of labyrinthine dysfunction in chronic Brucella-induced encephalitis.

Anterior lumbar interbody fusion (ALIF): a review of the procedure and associated complications

Degenerative disc disease and facet joint disease involving the lumbar spine are common in the aging population and are the most frequent causes of disability. Surgical interbody fusion of degenerative levels is the most common management technique. This is an effective treatment option to stabilize the spine and reduce mechanical pain and provides indirect decompression of the neural elements while restoring lordosis and correcting the deformity. Depending on the direction of the approach to the vertebral column, various techniques have been described. Anterior lumbar interbody fusion (ALIF) offers clear and wide visualization of the disc allowing the use of large interbody grafts, which provide a significant biomechanical advantage over other types of fusion. The transperitoneal approach is a much older technique and it is not commonly performed unless in isolated cases with extensive retroperitoneal scaring following multiple abdominal surgeries. The transperitoneal approach has been associated with higher rates of bowel injury, ileus, and retrograde ejaculation, and is limited at the L5–S1 segment, hence many spine surgeons favor a retroperitoneal approach. The major setback of ALIF is the need for great vessel mobilization. This manipulation of the vessels may lead to deep vein thrombosis and a direct vascular injury. This makes vascular anatomy studies in the preoperative stage invaluable in avoiding vascular injury. Other complications include possible injury to intraperitoneal and retroperitoneal organs, especially in patients with previous surgery and adhesions. Manipulation of the intestines causes postoperative ileus which lasts a few days. Sexual dysfunction in form of retrograde ejaculation is another complication seen in patients following ALIF and this has been attributed to injury to the superior hypogastric sympathetic nerves in the lower lumbar region.This article reviews the ALIF procedure i. e., transperitoneal and retroperitoneal approaches, and the associated intraoperative, early, and late complications.

Enhanced peripheral nerve regeneration by mechano-electrical stimulation

To address limitations in current approaches for treating large peripheral nerve defects, the presented study evaluated the feasibility of functional material-mediated physical stimuli on peripheral nerve regeneration. Electrospun piezoelectric poly(vinylidene fluoride-trifluoroethylene) nanofibers were utilized to deliver mechanical actuation-activated electrical stimulation to nerve cells/tissues in a non-invasive manner. Using morphologically and piezoelectrically optimized nanofibers for neurite extension and Schwann cell maturation based on in vitro experiments, piezoelectric nerve conduits were synthesized and implanted in a rat sciatic nerve transection model to bridge a critical-sized sciatic nerve defect (15 mm). A therapeutic shockwave system was utilized to periodically activate the piezoelectric effect of the implanted nerve conduit on demand. The piezoelectric nerve conduit-mediated mechano-electrical stimulation (MES) induced enhanced peripheral nerve regeneration, resulting in full axon reconnection with myelin regeneration from the proximal to the distal ends over the critical-sized nerve gap. In comparison, a control group, in which the implanted piezoelectric conduits were not activated in vivo, failed to exhibit such nerve regeneration. In addition, at both proximal and distal ends of the implanted conduits, a decreased number of damaged myelination (ovoids), an increased number of myelinated nerves, and a larger axonal diameter were observed under the MES condition as compared to the control condition. Furthermore, unlike the control group, the MES condition exhibited a superior functional nerve recovery, assessed by walking track analysis and polarization-sensitive optical coherence tomography, demonstrating the significant potential of the piezoelectric conduit-based physical stimulation approach for the treatment of peripheral nerve injury.

Transcervical, retropharyngeal odontoidectomy - Anatomical considerations.

Anterior craniocervical junction lesions have always been a challenge for neurosurgeons. Presenting with lower cranial nerve dysfunction and symptoms of brainstem compression, decompression is often required. While posterior approaches offer indirect ventral brainstem decompression, direct decompression via odontoidectomy is necessary when they fail. The transoral and endoscopic endonasal approaches have been explored but come with their own limitations and risks. A novel retropharyngeal approach to the cervical spine has shown promising results with reduced complications. This study aims to explore the feasibility and potential advantages of the anterior retropharyngeal approach for accessing the odontoid process. To investigate the anatomical aspects of the anterior retropharyngeal approach, a paramedian skin incision was performed below the submandibular gland on two cadaveric specimens. The subcutaneous tissue followed by the platysma is dissected, and the superficial fascial layer is opened. The plane between the vascular sheath laterally and the pharyngeal structures medially is entered below the branching point of the facial vein and internal jugular vein. After reaching the prevertebral plane, further dissection cranially is done in a blunt fashion below the superior pharyngeal nerve and artery. Various anatomical aspects were highlighted during this approach. The anterior, submandibular retropharyngeal approach to the cervical spine was performed successfully on two cadavers highlighting relevant anatomical structures, including the carotid artery and the glossopharyngeal, hypoglossal, and vagus nerves. This approach offered wide exposure, avoidance of oropharyngeal contamination, and potential benefit in repairing cerebrospinal fluid fistulas. For accessing the craniocervical junction, the anterior retropharyngeal approach is a viable technique that offers many advantages. However, when employing this approach, surgeons must have adequate anatomical knowledge and technical proficiency to ensure better outcomes. Further studies are needed to enhance our anatomical variations understanding and reduce intraoperative risks.

Clinical, Radiological, and Histopathological Findings of Post-Exenterated Mucormycosis Specimens

Introduction: A sharp upsurge in the number of coronavirus disease-associated mucormycosis cases was noted during the second wave of coronavirus disease in India. The fungal hyphae spread from the nasal mucosa, orbit to the brain, hence otherwise called rhino-orbito-cerebral mucormycosis (ROCM). Prompt diagnosis and early initiation of treatment with amphotericin B, aggressive surgical debridement of the PNS, and orbital exenteration, where indicated, are essential for successful outcome. This study is done to enumerate the clinical, radiological, and histopathological findings of post-exenterated specimens of ROCM. Methods: This is a non-randomized cross-sectional study conducted at a tertiary care center. Ten post-exenterated specimens were examined histopathologically for the involvement of the central retinal artery, superior ophthalmic vein (SOV), optic nerve, muscle, and orbital fat showing necrosis. Clinical findings of these 10 patients were studied retrospectively for visual loss, proptosis, extraocular movements for muscle involvement, scleral necrosis, and fundus findings for artery or vein occlusions. Preoperative magnetic resonance imaging (MRI) findings like the number of orbital quadrants showing soft tissue thickening or tissue enhancement, diffusion restriction in the optic nerve, soft tissue enhancement seen at the orbital apex or superior orbital fissure, loss of flow void in the left internal carotid artery, enlargement of the SOV containing filling defect on post-contrast images were noted. Results: Optic nerve involvement was seen in 100% patients clinically, 70% on MRI, and 50% on histopathological examination (HPE). Muscle involvement was seen in 100% patients clinically, 90% on MRI, and 80% on HPE. None of the patients had scleral necrosis clinically. Scleral tenting was seen in 20% patients on MRI and 20% on HPE. Clinically, central retinal artery involvement was seen in 40%, and cilioretinal artery involvement was seen in 10%. MRI could not give much information on artery involvement. Clinically, none of them had central retinal vein occlusion. 20% had an enlarged SOV seen on MRI. HPE showed vascular involvement in 90% of the specimens. Conclusion: Clinical, radiological, and histopathological findings play a major role in the diagnosis, staging, and follow-up of ROCM.