Clinical outcomes of peripheral nerve interfaces for rehabilitation in paralysis and amputation: a literature review.

Peripheral nerve interfaces (PNIs) are electrical systems designed to integrate with peripheral nerves in patients, such as following central nervous system (CNS) injuries to augment or replace CNS control and restore function. We review the literature for clinical trials and studies containing clinical outcome measures to explore the utility of human applications of PNIs. We discuss the various types of electrodes currently used for PNI systems and their functionalities and limitations. We discuss important design characteristics of PNI systems, including biocompatibility, resolution and specificity, efficacy, and longevity, to highlight their importance in the current and future development of PNIs. The clinical outcomes of PNI systems are also discussed. Finally, we review relevant PNI clinical trials that were conducted, up to the present date, to restore the sensory and motor function of upper or lower limbs in amputees, spinal cord injury patients, or intact individuals and describe their significant findings. This review highlights the current progress in the field of PNIs and serves as a foundation for future development and application of PNI systems.

Treatment of Intrathecal Drug Pump Flipping Using Fascial Flaps: A Technical Description and Case Series.

BACKGROUND AND OBJECTIVES: Intrathecal drug therapy is a common treatment for dystonia, pain, and spasticity using implanted pump and catheter systems. Standardized management of intrathecal drug pump (ITDP) migration and flipping has not been well established in the literature. This study reports the use of soft tissue to address less common pump complications such as pump flipping, migration, and difficulty in medication refill. METHODS: A retrospective chart review of intrathecal pump cases performed by two surgeons between February 2020 and August 2022 was conducted. Patients with complications such as pump flipping, migration, or challenges in medication refill treated with soft tissue flaps were included. Patient demographics, comorbidities, and perioperative data were collected. RESULTS: A total of five patients with ITDP complicated by pump flipping, migration, malposition, or difficulty in medication refill that were treated using fascial flaps were included in the study. Three technical considerations when revising ITDP complications are secure pump anchoring, reliable wound closure, and ease of pump medication refill. Cases 1 and 2 demonstrate the technique of secure pump anchoring with a rectus fascial flap. Cases 3 and 4 show a technique to achieve reliable vascularized wound closure, and case 5 describes a technique to solve an uncommon problem of a thick subcutaneous abdominal tissue preventing the refill of the ITDP medication. CONCLUSION: Soft tissue flaps may serve as a treatment option for patients with uncommon ITDP complications. De-epithelialized dermal fasciocutaneous or fascial flaps may be developed to anchor the pump more securely. Cross-discipline collaboration may further delineate the technique, benefits, and outcomes of this approach.

Electrospinography for non-invasively recording spinal sensorimotor networks in humans.

Objective. Currently, few non-invasive measures exist for directly measuring spinal sensorimotor networks. Electrospinography (ESG) is one non-invasive method but is primarily used to measure evoked responses or for monitoring the spinal cord during surgery. Our objectives were to evaluate the feasibility of ESG to measure spinal sensorimotor networks by determining spatiotemporal and functional connectivity changes during single-joint movements at the spinal and cortical levels.Approach. We synchronously recorded electroencephalography (EEG), electromyography, and ESG in ten neurologically intact adults while performing one of three lower-limb tasks (no movement, plantar-flexion and knee flexion) in the prone position. A multi-pronged approach was applied for removing artifacts usingH∞filtering, artifact subspace reconstruction and independent component (IC) analysis. Next, data were segmented by task and ICs of EEG were clustered across participants. Within-participant analysis of ICs and ESG data was conducted, and ESG was characterized in the time and frequency domains. Generalized partial directed coherence analysis was performed within ICs and between ICs and ESG data by participant and task.Results.K-means clustering resulted in five clusters of ICs at Brodmann areas (BAs) 9, BA 8, BA 39, BA 4, and BA 22. Areas associated with motor planning, working memory, visual processing, movement, and attention, respectively. Time-frequency analysis of ESG data found localized changes during movement execution when compared to no movement. Lastly, we found bi-directional changes in functional connectivity (p < 0.05, adjusted for multiple comparisons) within IC's and between IC's and ESG sensors during movement when compared to the no movement condition.Significance. To our knowledge this is the first report using high density ESG for characterizing single joint lower limb movements. Our findings provide support that ESG contains information about efferent and afferent signaling in neurologically intact adults and suggests that we can utilize ESG to directly study the spinal cord.

Impact of Upper Limb Motor Recovery on Functional Independence after Traumatic Low Cervical Spinal Cord Injury.

Cervical Spinal Cord Injury (SCI) causes devastating loss of upper limb function and independence. Restoration of upper limb function can have a profound impact on independence and quality-of-life. In low-cervical SCI (level C5-C8), upper limb function can be restored via reinnervation strategies such as nerve transfer surgery. However, the translation of recovered upper limb motor function into functional independence in activities of daily living (ADLs) remains unknown in low cervical SCI (i.e., tetraplegia). The objective of this study was to evaluate the association of patterns in upper limb motor recovery with functional independence in ADLs. This will then inform prioritization of reinnervation strategies focused to maximize function in patients with tetraplegia. This retrospective study performed a secondary analysis of low cervical SCI patients (C5-C8) enrolled in the SCI Model Systems (SCIMS) database. Baseline neurological examinations and their association with functional independence in major ADLs, i.e., eating, bladder management, and transfers (bed/wheelchair/chair) were evaluated. Motor functional recovery was defined as achieving motor strength, in modified research council (MRC) grade, of 3/5 at one-year from 2/5 at baseline. The association of motor function recovery with functional independence at one year follow-up was compared in patients with recovered elbow flexion (C5), wrist extension (C6), elbow extension (C7), and finger flexion (C8). A multivariable logistic regression analysis, adjusting for known factors influencing recovery following SCI, was performed to evaluate the impact of motor function at one year on a composite outcome of functional independence in major ADLs. Composite outcome was defined as functional independence measure score of 6 or higher (complete independence) in at least 2 domains among eating, bladder management, and transfers. Between 1992 and 2016, 1,090 patients with low cervical SCI and complete neurological/ functional measures were included. At baseline, 67% of patients had complete SCI and 33% had incomplete SCI. The majority of patients were dependent in eating, bladder management, and transfers. At one-year follow-up, the largest proportion of patients who recovered motor function in finger flexion (C8) and elbow extension (C7) gained independence in eating, bladder management, and transfers. In multivariable analysis, patients who had recovered finger flexion (C8) or elbow extension (C7) had higher odds of gaining independence in a composite of major ADLs (odds ratio [OR]=3.13 and OR=2.87, respectively, p<0.001). Age 60 years (OR=0.44, p=0.01), and complete SCI (OR=0.43, p=0.002) were associated with reduced odds of gaining independence in ADLs. After cervical SCI, finger flexion (C8) and elbow extension (C7) recovery translate into greater independence in eating, bladder management and transfers. These results can be used to design individualized reinnervation plans to reanimate upper limb function and maximize independence in patients with low cervical SCI.

Spinal cord stimulation for chronic pain treatment following sacral chordoma resection: illustrative case.

BACKGROUND: Cancer-related or postoperative pain can occur following sacral chordoma resection. Despite a lack of current recommendations for cancer pain treatment, spinal cord stimulation (SCS) has demonstrated effectiveness in addressing cancer-related pain. OBSERVATIONS: A 76-year-old female with a sacral chordoma underwent anterior osteotomies and partial en bloc sacrectomy. She subsequently presented with chronic pain affecting both buttocks and posterior thighs and legs, significantly impeding her daily activities. She underwent a staged epidural SCS paddle trial and permanent system placement using intraoperative neuromonitoring. The utilization of percutaneous leads was not viable because of her history of spinal fluid leakage, multiple lumbosacral surgeries, and previous complex plastic surgery closure. The patient reported a 62.5% improvement in her lower-extremity pain per the modified Quadruple Visual Analog Scale and a 50% improvement in the modified Pain and Sleep Questionnaire 3-item index during the SCS trial. Following permanent SCS system placement and removal of her externalized lead extenders, she had an uncomplicated postoperative course and reported notable improvements in her pain symptoms. LESSONS: This case provides a compelling illustration of the successful treatment of chronic pain using SCS following radical sacral chordoma resection. Surgeons may consider this treatment approach in patients presenting with refractory pain following spinal tumor resection.

United States regulatory approval of medical devices used for endovascular neurosurgery: A two-decade review of FDA regulatory files.

BACKGROUND: The evolution of neuroendovascular technologies has progressed substantially. Over the last two decades, the introduction of new endovascular devices has facilitated treatment for more patients, and as a result, the regulatory environment concerning neuroendovascular devices has evolved rapidly in response. OBJECTIVE: To examine trends in the approval of neuroendovascular devices by the United States Food and Drug Administration (FDA) over the last 20 years. METHODS: Open-access US FDA databases were queried between January 2000 and December 2022 for all devices approved by the Neurological Devices Advisory Committee. Neuroendovascular devices were manually classified and grouped by category. Device approval data, including approval times, approval pathway, and presence of predicate devices, were examined. RESULTS: A total of 3186 neurological devices were approved via various US FDA pathways during the study period. 320 (10.0%) corresponded to neuroendovascular devices, of which 301 (94.1%) were approved via the 510(k) pathway. The percentage of 510(k) pathway neuroendovascular devices increased from 6.9% to 14.3% of all neuro devices before and after 2015, respectively. There was an increase in approval times for neuroendovascular devices cleared after 2015. CONCLUSION: Over the last two decades, the neuroendovascular device armamentarium has rapidly expanded, especially after positive stroke trials in 2015. Regulatory approval times are significantly affected by device category, generation, company size, and company location, and a vast majority are approved by the 510(k) pathway. These results can guide further innovation in the endovascular device space and may act as a roadmap for future regulatory planning.

Internal iliac artery aneurysm masquerading as a sciatic nerve schwannoma: illustrative case.

BACKGROUND: Schwannomas are common peripheral nerve sheath tumors. Imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT) can help to distinguish schwannomas from other types of lesions. However, there have been several reported cases describing the misdiagnosis of aneurysms as schwannomas. OBSERVATIONS: A 70-year-old male with ongoing pain despite spinal fusion surgery underwent MRI. A lesion was noted along the left sciatic nerve, which was believed to be a sciatic nerve schwannoma. During the surgery for planned neurolysis and tumor resection, the lesion was noted to be pulsatile. Electromyography mapping and intraoperative ultrasound confirmed vascular pulsations and turbulent flow within the aneurysm, so the surgery was aborted. A formal CT angiogram revealed the lesion to be an internal iliac artery (IIA) branch aneurysm. The patient underwent coil embolization with complete obliteration of the aneurysm. LESSONS: The authors report the first case of an IIA aneurysm misdiagnosed as a sciatic nerve schwannoma. Surgeons should be aware of this potential misdiagnosis and potentially use other imaging modalities to confirm the lesion before proceeding with surgery.

Mechanomyography as a Surgical Adjunct for Treatment of Chronic Entrapment Neuropathy: A Case Series.

BACKGROUND: Chronic entrapment neuropathy results in a clinical syndrome ranging from mild pain to debilitating atrophy. There remains a lack of objective metrics that quantify nerve dysfunction and guide surgical decision-making. Mechanomyography (MMG) reflects mechanical motor activity after stimulation of neuromuscular tissue and may indicate underlying nerve dysfunction. OBJECTIVE: To evaluate the role of MMG as a surgical adjunct in treating chronic entrapment neuropathies. METHODS: Patients 18 years or older with cubital tunnel syndrome (n = 8) and common peroneal neuropathy (n = 15) were enrolled. Surgical decompression of entrapped nerves was performed with intraoperative MMG of the hypothenar and tibialis anterior muscles. MMG stimulus thresholds (MMG-st) were correlated with compound muscle action potential (CMAP), motor nerve conduction velocity, baseline functional status, and clinical outcomes. RESULTS: After nerve decompression, MMG-st significantly reduced, the mean reduction of 0.5 mA (95% CI: 0.3-0.7, P < .001). On bivariate analysis, MMG-st exhibited significant negative correlation with common peroneal nerve CMAP ( P < .05), but no association with ulnar nerve CMAP and motor nerve conduction velocity. On preoperative electrodiagnosis, 60% of nerves had axonal loss and 40% had conduction block. The MMG-st was higher in the nerves with axonal loss as compared with the nerves with conduction block. MMG-st was negatively correlated with preoperative hand strength (grip/pinch) and foot-dorsiflexion/toe-extension strength ( P < .05). At the final visit, MMG-st significantly correlated with pain, PROMIS-10 physical function, and Oswestry Disability Index ( P < .05). CONCLUSION: MMG-st may serve as a surgical adjunct indicating axonal integrity in chronic entrapment neuropathies which may aid in clinical decision-making and prognostication of functional outcomes.

Operative Technique and Nuances for the Stereoelectroencephalographic (SEEG) Methodology Utilizing a Robotic Stereotactic Guidance System.

The SEEG methodology has gained favor in North America over the last decade as a means of localizing the epileptogenic zone (EZ) prior to epilepsy surgery. Recently, the application of a robotic stereotactic guidance system for implantation of SEEG electrodes has become more popular in many epilepsy centers. The technique for the use of the robot requires extreme precision in the pre-surgical planning phase and then the technique is streamlined during the operative portion of the methodology, as the robot and surgeon work in concert to implant the electrodes. Herein is detailed precise operative methodology of using the robot to guide implantation of SEEG electrodes. A major limitation of the procedure, namely its heavy reliance on the ability to register the patient to a preoperative volumetric magnetic resonance image (MRI), is also discussed. Overall, this procedure has been shown to have a low morbidity rate and an extremely low mortality rate. The use of a robotic stereotactic guidance system for the implantation of SEEG electrodes is an efficient, fast, safe, and accurate alternative to conventional manual implantation strategies.

Association of upper-limb neurological recovery with functional outcomes in high cervical spinal cord injury.

OBJECTIVE: High cervical spinal cord injury (SCI) results in complete loss of upper-limb function, resulting in debilitating tetraplegia and permanent disability. Spontaneous motor recovery occurs to varying degrees in some patients, particularly in the 1st year postinjury. However, the impact of this upper-limb motor recovery on long-term functional outcomes remains unknown. The objective of this study was to characterize the impact of upper-limb motor recovery on the degree of long-term functional outcomes in order to inform priorities for research interventions that restore upper-limb function in patients with high cervical SCI. METHODS: A prospective cohort of high cervical SCI (C1-4) patients with American Spinal Injury Association Impairment Scale (AIS) grade A-D injury and enrolled in the Spinal Cord Injury Model Systems Database was included. Baseline neurological examinations and functional independence measures (FIMs) in feeding, bladder management, and transfers (bed/wheelchair/chair) were evaluated. Independence was defined as score ≥ 4 in each of the FIM domains at 1-year follow-up. At 1-year follow-up, functional independence was compared among patients who gained recovery (motor grade ≥ 3) in elbow flexors (C5), wrist extensors (C6), elbow extensors (C7), and finger flexors (C8). Multivariable logistic regression evaluated the impact of motor recovery on functional independence in feeding, bladder management, and transfers. RESULTS: Between 1992 and 2016, 405 high cervical SCI patients were included. At baseline, 97% of patients had impaired upper-limb function with total dependence in eating, bladder management, and transfers. At 1 year of follow-up, the largest proportion of patients who gained independence in eating, bladder management, and transfers had recovery in finger flexion (C8) and wrist extension (C6). Elbow flexion (C5) recovery had the lowest translation to functional independence. Patients who achieved elbow extension (C7) were able to transfer independently. On multivariable analysis, patients who gained elbow extension (C7) and finger flexion (C8) were 11 times more likely to gain functional independence (OR 11, 95% CI 2.8-47, p < 0.001) and patients who gained wrist extension (C6) were 7 times more likely to gain functional independence (OR 7.1, 95% CI 1.2-56, p = 0.04). Older age (≥ 60 years) and motor complete SCI (AIS grade A-B) reduced the likelihood of gaining independence. CONCLUSIONS: After high cervical SCI, patients who gained elbow extension (C7) and finger flexion (C8) had significantly greater independence in feeding, bladder management, and transfers than those with recovery in elbow flexion (C5) and wrist extension (C6). Recovery of elbow extension (C7) also increased the capability for independent transfers. This information can be used to set patient expectations and prioritize interventions that restore these upper-limb functions in patients with high cervical SCI.

Implantation accuracy and operative variables in robot-assisted stereoelectroencephalography.

OBJECTIVE: The stereoelectroencephalography (SEEG) procedure provides a unique 3D overview of the seizure-onset zone. Although the success of SEEG relies on the accuracy of depth electrode implantation, few studies have investigated how different implantation techniques and operative variables affect accuracy. This study examined the effect of two different electrode implantation techniques (external vs internal stylet) on implantation accuracy while controlling for other operative variables. METHODS: The implantation accuracy of 508 depth electrodes from 39 SEEG cases was measured after coregistration of postimplantation CT or MR images with planned trajectories. Two different implantation techniques were compared: preset length with internal stylet use and measured length with external stylet use. Correlations between implantation accuracy and technique type, entry angle, intended implantation depth, and other operative variables were determined statistically using multiple regression analysis. RESULTS: Multiple regression analysis showed that the internal stylet technique exhibited a larger target radial error (p = 0.046) and angular deviation (p = 0.039) with a smaller depth error (p < 0.001) than the external stylet technique. Entry angle and implantation depth were positively correlated with target radial error (p = 0.007 and < 0.001, respectively) only for the internal stylet technique. CONCLUSIONS: Better target radial accuracy was achieved when an external stylet was used to open the intraparenchymal pathway for the depth electrode. In addition, more oblique trajectories were equally accurate to orthogonal ones with the usage of an external stylet, while more oblique trajectories were associated with larger target radial errors with the usage of an internal stylet (without an external stylet).

Response to Letter Regarding "Predictive Value of Preoperative Serum Albumin in Patients With Metastatic Spine Diseases: A Statistical Comment".

We thank the authors for their interest in and commentary on "Preoperative Serum Albumin Level Predicts Length of Stay and Perioperative Adverse Events Following Vertebral Corpectomy and Posterior Stabilization for Metastatic Spine Disease." We appreciate the opportunity to respond to their comments herein.

Magnetic Resonance-Guided Stereotaxy for Infusions to the Pig Brain.

The overall goal of this procedure is to perform stereotaxy in the pig brain with real-time magnetic resonance (MR) visualization guidance to provide precise infusions. The subject was positioned prone in the MR bore for optimal access to the top of the skull with the torso raised, the neck flexed, and the head inclined downward. Two anchor pins anchored on the bilateral zygoma held the head steady using the head holder. A magnetic resonance imaging (MRI) flex-coil was placed rostrally across the head holder so that the skull was accessible for the intervention procedure. A planning grid placed on the scalp was used to determine the appropriate entry point of the cannula. The stereotactic frame was secured and aligned iteratively through software projection until the projected radial error was less than 0.5 mm. A hand drill was used to create a burr hole for insertion of the cannula. A gadolinium-enhanced co-infusion was used to visualize the infusion of a cell suspension. Repeated T1-weighted MRI scans were registered in real time during the agent delivery process to visualize the volume of gadolinium distribution. MRI-guided stereotaxy allows for precise and controlled infusion into the pig brain, with concurrent monitoring of cannula insertion accuracy and determination of the agent volume of distribution.

Preoperative Serum Albumin Level Predicts Length of Stay and Perioperative Adverse Events Following Vertebral Corpectomy and Posterior Stabilization for Metastatic Spine Disease.

STUDY DESIGN: Retrospective review of a prospectively collected national database. OBJECTIVES: To determine the association between preoperative serum albumin levels and perioperative adverse events (AEs) following vertebral corpectomy and posterior stabilization for metastatic spine disease. METHODS: The 2010 to 2019 American College of Surgeons' National Surgical Quality Improvement (ACS-NSQIP) database was used to identify all patients undergoing vertebral corpectomy and posterior stabilization for metastatic spine disease. Receiver operative characteristic (ROC) curve analysis was used to determine preoperative serum albumin cut-off values for predicting perioperative AEs. Low preoperative serum albumin was defined as serum albumin below this cut-off value. RESULTS: A total of 301 patients were included in the study. ROC curve analysis demonstrated serum albumin < 3.25 g/dL as a cut-off value for predicting perioperative AEs. The low serum albumin group had a higher overall perioperative AEs (P = .041), longer post-operative LOS (P < .001), higher 30-day reoperation rate (P = .014), and a higher in-hospital mortality rate (P = .046). Multivariate analysis demonstrated that low preoperative serum albumin was associated with higher perioperative AEs. CONCLUSIONS: Low serum albumin level is associated with higher perioperative AEs, longer postoperative LOS, and higher rates of 30-day reoperation and in-hospital mortality among patients undergoing vertebral corpectomy and posterior stabilization for metastatic spine disease. Strategies to improve preoperative nutritional status in patients undergoing this procedure may improve these perioperative outcome measures within this surgical population. LEVEL OF EVIDENCE: III.

Incorporating Intraoperative Mechanomyography to Peripheral Nerve Decompression Surgery.

BACKGROUND: Mechanomyography (MMG) is a novel intraoperative tool to detect and quantify nerve activity with high sensitivity as compared with traditional electromyographic recordings. MMG reflects the mechanical vibrations of single motor units detected through accelerometer sensors after direct motor neuron stimulation. OBJECTIVE: To determine the feasibility of applying intraoperative MMG during peripheral nerve surgery. METHODS: A total of 20 consecutive patients undergoing surgical decompression of the ulnar nerve at the cubital tunnel or common peroneal nerve at the fibular head were included in this study. Intraoperatively, the common peroneal and ulnar nerves were directly stimulated through the MMG electrode probe starting at 0.1 mA threshold and increasing by 0.1 mA increments until target muscle activity was noted. The lowest threshold current required to elicit a muscle response was recorded before decompression and after proximal and distal nerve decompression. RESULTS: Of the patients, 80% (16/20) had MMG signals detected and recorded. Four patients were unable to have MMG signal detected despite direct nerve visualization and complete neurolysis. The mean predecompression stimulus threshold was 1.59 ± 0.19 mA. After surgical decompression, improvement in the mean MMG stimulus threshold was noted (0.47 ± 0.03 mA, P = .0002). Postoperatively, all patients endorsed symptomatic improvement with no complications. CONCLUSION: MMG may provide objective guidance for the intraoperative determination of the extent of nerve decompression. Lower stimulus thresholds may represent increased sparing of axonal tissue. Future work should focus on validating normative values of MMG stimulus thresholds in various nerves and establishing clinical associations with functional outcomes.

Upper Limb Nerve Transfer Surgery in Patients With Tetraplegia.

Importance: Cervical spinal cord injury (SCI) causes devastating loss of upper extremity function and independence. Nerve transfers are a promising approach to reanimate upper limbs; however, there remains a paucity of high-quality evidence supporting a clinical benefit for patients with tetraplegia. Objective: To evaluate the clinical utility of nerve transfers for reanimation of upper limb function in tetraplegia. Design, Setting, and Participants: In this prospective case series, adults with cervical SCI and upper extremity paralysis whose recovery plateaued were enrolled between September 1, 2015, and January 31, 2019. Data analysis was performed from August 2021 to February 2022. Interventions: Nerve transfers to reanimate upper extremity motor function with target reinnervation of elbow extension and hand grasp, pinch, and/or release. Main Outcomes and Measures: The primary outcome was motor strength measured by Medical Research Council (MRC) grades 0 to 5. Secondary outcomes included Sollerman Hand Function Test (SHFT); Michigan Hand Outcome Questionnaire (MHQ); Disabilities of Arm, Shoulder, and Hand (DASH); and 36-Item Short Form Health Survey (SF-36) physical component summary (PCS) and mental component summary (MCS) scores. Outcomes were assessed up to 48 months postoperatively. Results: Twenty-two patients with tetraplegia (median age, 36 years [range, 18-76 years]; 21 male [95%]) underwent 60 nerve transfers on 35 upper limbs at a median time of 21 months (range, 6-142 months) after SCI. At final follow-up, upper limb motor strength improved significantly: median MRC grades were 3 (IQR, 2.5-4; P = .01) for triceps, with 70% of upper limbs gaining an MRC grade of 3 or higher for elbow extension; 4 (IQR, 2-4; P < .001) for finger extensors, with 79% of hands gaining an MRC grade of 3 or higher for finger extension; and 2 (IQR, 1-3; P < .001) for finger flexors, with 52% of hands gaining an MRC grade of 3 or higher for finger flexion. The secondary outcomes of SHFT, MHQ, DASH, and SF36-PCS scores improved beyond the established minimal clinically important difference. Both early (<12 months) and delayed (≥12 months) nerve transfers after SCI achieved comparable motor outcomes. Continual improvement in motor strength was observed in the finger flexors and extensors across the entire duration of follow-up. Conclusions and Relevance: In this prospective case series, nerve transfer surgery was associated with improvement of upper limb motor strength and functional independence in patients with tetraplegia. Nerve transfer is a promising intervention feasible in both subacute and chronic SCI.

Melanoma metastasis to the femoral nerve: a novel case of melanoma masquerading as mononeuropathy. Illustrative case.

BACKGROUND: Metastatic cancer may involve the central and peripheral nervous system, usually in the late stages of disease. At this point, most patients have been diagnosed and treated for widespread systemic disease. Rarely is the involvement of the peripheral nervous system the presenting manifestation of malignancy. One reason for this is a proposed "blood-nerve barrier" that renders the nerve sheath a relatively privileged site for metastases. OBSERVATIONS: The authors presented a novel case of metastatic melanoma presenting as intractable leg pain and numbness. Further workup revealed concurrent disease in the brain and breast, prompting urgent treatment with radiation and targeted immunotherapy. LESSONS: This case highlights the rare presentation of metastatic melanoma as a mononeuropathy. Although neurological complications of metastases tend to occur in later stages of disease after initial diagnosis and treatment, one must remember to consider malignancy in the initial differential diagnosis of mononeuropathy.

Improvement in sagittal alignment and mechanical low-back pain following deep brain stimulation for Parkinson's disease: illustrative case.

BACKGROUND: Parkinson's disease (PD) is a common neurogenerative disease marked by the characteristic triad of bradykinesia, rigidity, and tremor. A significant percentage of patients with PD also demonstrate postural abnormalities (camptocormia) that limit ambulation and accelerate degenerative pathologies of the spine. Although deep brain stimulation (DBS) is a well-established treatment for the motor fluctuations and tremor seen in PD, the efficacy of DBS on postural abnormalities in these patients is less clear. OBSERVATIONS: The authors present a patient with a history of PD and prior lumbosacral fusion who underwent bilateral subthalamic nucleus DBS and experienced immediate improvement in sagittal alignment and subjective relief of mechanical low-back pain. LESSONS: DBS may improve postural abnormalities seen in PD and potentially delay or reduce the need for spinal deformity surgery.

The role of endoscopic endonasal surgery in the management of prolactinomas based on their invasiveness into the cavernous sinus.

PURPOSE: To review our institutional experience with the surgical management of prolactinomas through the endoscopic endonasal approach with specific focus on cavernous sinus invasion. METHODS: Clinical and radiographic data were collected retrospectively from the electronic medical record of 78 consecutive patients with prolactinomas undergoing endoscopic endonasal resection from 2002 to 2019. Immediate and late post-operative remission were defined as prolactin < 20 ng/mL within 14 days and 1-year of surgery without adjuvant therapy, respectively. Cavernous sinus invasion was quantified by Knosp score. RESULTS: A total of 78 patients with prolactinoma, 59% being male, underwent surgical resection with a mean age of 37 ± 13 years. Indications for surgery were medication resistance in 38 patients (48.7%), medication intolerance in 11 (14.1%), and patient preference in 29 (37.2%). Patients with Knosp 0-2 achieved higher immediate remission rates (83.8%) compared to patients with Knosp 3 (58.8%) and Knosp 4 (41.7%) patients (p = 0.003). Long-term remission rates were 48.7% and increased to 71.8% when combined with adjuvant treatments. Knosp 4 prolactinomas had significantly higher tumor volumes, higher preoperative prolactin levels, higher recurrence rates, higher rates of adjuvant therapy utilization, and were more likely to have failed dopamine agonist therapy compared to other tumor grades (p < 0.05). We encountered 18 complications in our series, and no cerebrospinal fluid leaks. CONCLUSION: The endoscopic endonasal approach is a safe and effective modality that can be employed in properly selected patients with invasive prolactinomas. It is associated with improved control and remission rates despite cavernous sinus invasion, though at a lower rate than without invasion.

Scoring systems of metabolic syndrome and prediction of cardiovascular events: A population based cohort study.

BACKGROUND AND AIMS: Continuous scoring systems were developed versus traditional dichotomous approaches to define metabolic syndrome. The current study was carried out to evaluate the ability of scoring systems to predict fatal and nonfatal cardiovascular events. MATERIALS AND METHODS: The data of 5147 individuals aged 18 years or more obtained from a population-based cohort study were analyzed. The occurrence of atherosclerotic cardiovascular disease (ASCVD) in the period of 7 years follow-up was considered as the associated outcome. Joint Interim Statement (JIS) definition, as a traditional definition of metabolic syndrome (MetS), and two versions of MetS scoring systems, based on standardized regression weights from structural equation modeling (SEM) and simple method for quantifying metabolic syndrome (siMS) were considered as potential predictors. RESULTS: The scoring systems, particularly, based on SEM, were observed to have a significant association with composite cardiovascular events (HR = 1.388 [95% CI = 1.153-1.670], p = .001 in men and HR = 1.307 [0.95% CI = 1.120-1.526] in women) in multiple Cox proportional hazard regression analyses, whereas the traditional definition of MetS did not show any significant association. While both two scoring systems showed acceptable predictive abilities for cardiovascular events in women (MetS score based on SEM: area of under curve [AUC] = 0.7438 [95% CI = 0.6195-0.7903] and siMS: AUC = 0.7207 [95% CI = 0.6676-0.7738]), the two systems were not acceptable for identifying risk in men. CONCLUSION: Unlike the dichotomous definition of MetS, the scoring systems showed an independent association with cardiovascular events. Scoring systems, particularly those based on SEM, may be useful for the prediction of cardiovascular events in women.