A critical period of prehearing spontaneous Ca2+ spiking is required for hair-bundle maintenance in inner hair cells.

Sensory-independent Ca2+ spiking regulates the development of mammalian sensory systems. In the immature cochlea, inner hair cells (IHCs) fire spontaneous Ca2+ action potentials (APs) that are generated either intrinsically or by intercellular Ca2+ waves in the nonsensory cells. The extent to which either or both of these Ca2+ signalling mechansims are required for IHC maturation is unknown. We find that intrinsic Ca2+ APs in IHCs, but not those elicited by Ca2+ waves, regulate the maturation and maintenance of the stereociliary hair bundles. Using a mouse model in which the potassium channel Kir2.1 is reversibly overexpressed in IHCs (Kir2.1-OE), we find that IHC membrane hyperpolarization prevents IHCs from generating intrinsic Ca2+ APs but not APs induced by Ca2+ waves. Absence of intrinsic Ca2+ APs leads to the loss of mechanoelectrical transduction in IHCs prior to hearing onset due to progressive loss or fusion of stereocilia. RNA-sequencing data show that pathways involved in morphogenesis, actin filament-based processes, and Rho-GTPase signaling are upregulated in Kir2.1-OE mice. By manipulating in vivo expression of Kir2.1 channels, we identify a "critical time period" during which intrinsic Ca2+ APs in IHCs regulate hair-bundle function.

Neuroplastin genetically interacts with Cadherin 23 and the encoded isoform Np55 is sufficient for cochlear hair cell function and hearing.

Mammalian hearing involves the mechanoelectrical transduction (MET) of sound-induced fluid waves in the cochlea. Essential to this process are the specialised sensory cochlear cells, the inner (IHCs) and outer hair cells (OHCs). While genetic hearing loss is highly heterogeneous, understanding the requirement of each gene will lead to a better understanding of the molecular basis of hearing and also to therapeutic opportunities for deafness. The Neuroplastin (Nptn) gene, which encodes two protein isoforms Np55 and Np65, is required for hearing, and homozygous loss-of-function mutations that affect both isoforms lead to profound deafness in mice. Here we have utilised several distinct mouse models to elaborate upon the spatial, temporal, and functional requirement of Nptn for hearing. While we demonstrate that both Np55 and Np65 are present in cochlear cells, characterisation of a Np65-specific mouse knockout shows normal hearing thresholds indicating that Np65 is functionally redundant for hearing. In contrast, we find that Nptn-knockout mice have significantly reduced maximal MET currents and MET channel open probabilities in mature OHCs, with both OHCs and IHCs also failing to develop fully mature basolateral currents. Furthermore, comparing the hearing thresholds and IHC synapse structure of Nptn-knockout mice with those of mice that lack Nptn only in IHCs and OHCs shows that the majority of the auditory deficit is explained by hair cell dysfunction, with abnormal afferent synapses contributing only a small proportion of the hearing loss. Finally, we show that continued expression of Neuroplastin in OHCs of adult mice is required for membrane localisation of Plasma Membrane Ca2+ ATPase 2 (PMCA2), which is essential for hearing function. Moreover, Nptn haploinsufficiency phenocopies Atp2b2 (encodes PMCA2) mutations, with heterozygous Nptn-knockout mice exhibiting hearing loss through genetic interaction with the Cdh23ahl allele. Together, our findings provide further insight to the functional requirement of Neuroplastin for mammalian hearing.

Biophysical and morphological changes in inner hair cells and their efferent innervation in the ageing mouse cochlea.

KEY POINTS: Age-related hearing loss is a progressive hearing loss involving environmental and genetic factors, leading to a decrease in hearing sensitivity, threshold and speech discrimination. We compared age-related changes in inner hair cells (IHCs) between four mouse strains with different levels of progressive hearing loss. The surface area of apical coil IHCs (9-12 kHz cochlear region) decreases by about 30-40% with age. The number of BK channels progressively decreases with age in the IHCs from most mouse strains, but the basolateral membrane current profile remains unchanged. The mechanoelectrical transducer current is smaller in mice harbouring the hypomorphic Cdh23 allele Cdh23ahl (C57BL/6J; C57BL/6NTac), but not in Cdh23-repaired mice (C57BL/6NTacCdh23+ ), indicating that it could contribute to the different progression of hearing loss among mouse strains. The degree of efferent rewiring onto aged IHCs, most likely coming from the lateral olivocochlea fibres, was correlated with hearing loss in the different mouse strains. ABSTRACT: Inner hair cells (IHCs) are the primary sensory receptors of the mammalian cochlea, transducing acoustic information into electrical signals that are relayed to the afferent neurons. Functional changes in IHCs are a potential cause of age-related hearing loss. Here, we have investigated the functional characteristics of IHCs from early-onset hearing loss mice harbouring the allele Cdh23ahl (C57BL/6J and C57BL/6NTac), from late-onset hearing loss mice (C3H/HeJ), and from mice corrected for the Cdh23ahl mutation (C57BL/6NTacCdh23+ ) with an intermediate hearing phenotype. There was no significant loss of IHCs in the 9-12 kHz cochlear region up to at least 15 months of age, but their surface area decreased progressively by 30-40% starting from ∼6 months of age. Although the size of the BK current decreased with age, IHCs retained a normal KCNQ4 current and resting membrane potential. These basolateral membrane changes were most severe for C57BL/6J and C57BL/6NTac, less so for C57BL/6NTacCdh23+ and minimal or absent in C3H/HeJ mice. We also found that lateral olivocochlear (LOC) efferent fibres re-form functional axon-somatic connections with aged IHCs, but this was seen only sporadically in C3H/HeJ mice. The efferent post-synaptic SK2 channels appear prior to the establishment of the efferent contacts, suggesting that IHCs may play a direct role in re-establishing the LOC-IHC synapses. Finally, we showed that the size of the mechanoelectrical transducer (MET) current from IHCs decreased significantly with age in mice harbouring the Cdh23ahl allele but not in C57BL/6NTacCdh23+ mice, indicating that the MET apparatus directly contributes to the progression of age-related hearing loss.

MET currents and otoacoustic emissions from mice with a detached tectorial membrane indicate the extracellular matrix regulates Ca2+ near stereocilia.

KEY POINTS: The aim was to determine whether detachment of the tectorial membrane (TM) from the organ of Corti in Tecta/Tectb-/- mice affects the biophysical properties of cochlear outer hair cells (OHCs). Tecta/Tectb-/- mice have highly elevated hearing thresholds, but OHCs mature normally. Mechanoelectrical transducer (MET) channel resting open probability (Po ) in mature OHC is ∼50% in endolymphatic [Ca2+ ], resulting in a large standing depolarizing MET current that would allow OHCs to act optimally as electromotile cochlear amplifiers. MET channel resting Po in vivo is also high in Tecta/Tectb-/- mice, indicating that the TM is unlikely to statically bias the hair bundles of OHCs. Distortion product otoacoustic emissions (DPOAEs), a readout of active, MET-dependent, non-linear cochlear amplification in OHCs, fail to exhibit long-lasting adaptation to repetitive stimulation in Tecta/Tectb-/- mice. We conclude that during prolonged, sound-induced stimulation of the cochlea the TM may determine the extracellular Ca2+ concentration near the OHC's MET channels. ABSTRACT: The tectorial membrane (TM) is an acellular structure of the cochlea that is attached to the stereociliary bundles of the outer hair cells (OHCs), electromotile cells that amplify motion of the cochlear partition and sharpen its frequency selectivity. Although the TM is essential for hearing, its role is still not fully understood. In Tecta/Tectb-/- double knockout mice, in which the TM is not coupled to the OHC stereocilia, hearing sensitivity is considerably reduced compared with that of wild-type animals. In vivo, the OHC receptor potentials, assessed using cochlear microphonics, are symmetrical in both wild-type and Tecta/Tectb-/- mice, indicating that the TM does not bias the hair bundle resting position. The functional maturation of hair cells is also unaffected in Tecta/Tectb-/- mice, and the resting open probability of the mechanoelectrical transducer (MET) channel reaches values of ∼50% when the hair bundles of mature OHCs are bathed in an endolymphatic-like Ca2+ concentration (40 µM) in vitro. The resultant large MET current depolarizes OHCs to near -40 mV, a value that would allow optimal activation of the motor protein prestin and normal cochlear amplification. Although the set point of the OHC receptor potential transfer function in vivo may therefore be determined primarily by endolymphatic Ca2+ concentration, repetitive acoustic stimulation fails to produce adaptation of MET-dependent otoacoustic emissions in vivo in the Tecta/Tectb-/- mice. Therefore, the TM is likely to contribute to the regulation of Ca2+ levels around the stereocilia, and thus adaptation of the OHC MET channel during prolonged sound stimulation.

Loss of Baiap2l2 destabilizes the transducing stereocilia of cochlear hair cells and leads to deafness.

KEY POINTS: Mechanoelectrical transduction at auditory hair cells requires highly specialized stereociliary bundles that project from their apical surface, forming a characteristic graded 'staircase' structure. The morphogenesis and maintenance of these stereociliary bundles is a tightly regulated process requiring the involvement of several actin-binding proteins, many of which are still unidentified. We identify a new stereociliary protein, the I-BAR protein BAIAP2L2, which localizes to the tips of the shorter transducing stereocilia in both inner and outer hair cells (IHCs and OHCs). We find that Baiap2l2 deficient mice lose their second and third rows of stereocilia, their mechanoelectrical transducer current, and develop progressive hearing loss, becoming deaf by 8 months of age. We demonstrate that BAIAP2L2 localization to stereocilia tips is dependent on the motor protein MYO15A and its cargo EPS8. We propose that BAIAP2L2 is a new key protein required for the maintenance of the transducing stereocilia in mature cochlear hair cells. ABSTRACT: The transduction of sound waves into electrical signals depends upon mechanosensitive stereociliary bundles that project from the apical surface of hair cells within the cochlea. The height and width of these actin-based stereocilia is tightly regulated throughout life to establish and maintain their characteristic staircase-like structure, which is essential for normal mechanoelectrical transduction. Here, we show that BAIAP2L2, a member of the I-BAR protein family, is a newly identified hair bundle protein that is localized to the tips of the shorter rows of transducing stereocilia in mouse cochlear hair cells. BAIAP2L2 was detected by immunohistochemistry from postnatal day 2.5 (P2.5) throughout adulthood. In Baiap2l2 deficient mice, outer hair cells (OHCs), but not inner hair cells (IHCs), began to lose their third row of stereocilia and showed a reduction in the size of the mechanoelectrical transducer current from just after P9. Over the following post-hearing weeks, the ordered staircase structure of the bundle progressively deteriorates, such that, by 8 months of age, both OHCs and IHCs of Baiap2l2 deficient mice have lost most of the second and third rows of stereocilia and become deaf. We also found that BAIAP2L2 interacts with other key stereociliary proteins involved in normal hair bundle morphogenesis, such as CDC42, RAC1, EPS8 and ESPNL. Furthermore, we show that BAIAP2L2 localization to the stereocilia tips depends on the motor protein MYO15A and its cargo EPS8. We propose that BAIAP2L2 is key to maintenance of the normal actin structure of the transducing stereocilia in mature mouse cochlear hair cells.

Age-related changes in the biophysical and morphological characteristics of mouse cochlear outer hair cells.

KEY POINTS: Age-related hearing loss (ARHL) is a very heterogeneous disease, resulting from cellular senescence, genetic predisposition and environmental factors (e.g. noise exposure). Currently, we know very little about age-related changes occurring in the auditory sensory cells, including those associated with the outer hair cells (OHCs). Using different mouse strains, we show that OHCs undergo several morphological and biophysical changes in the ageing cochlea. Ageing OHCs also exhibited the progressive loss of afferent and efferent synapses. We also provide evidence that the size of the mechanoelectrical transducer current is reduced in ageing OHCs, highlighting its possible contribution in cochlear ageing. ABSTRACT: Outer hair cells (OHCs) are electromotile sensory receptors that provide sound amplification within the mammalian cochlea. Although OHCs appear susceptible to ageing, the progression of the pathophysiological changes in these cells is still poorly understood. By using mouse strains with a different progression of hearing loss (C57BL/6J, C57BL/6NTac, C57BL/6NTacCdh23+ , C3H/HeJ), we have identified morphological, physiological and molecular changes in ageing OHCs (9-12 kHz cochlear region). We show that by 6 months of age, OHCs from all strains underwent a reduction in surface area, which was not a sign of degeneration. Although the ageing OHCs retained a normal basolateral membrane protein profile, they showed a reduction in the size of the K+ current and non-linear capacitance, a readout of prestin-dependent electromotility. Despite these changes, OHCs have a normal Vm and retain the ability to amplify sound, as distortion product otoacoustic emission thresholds were not affected in aged, good-hearing mice (C3H/HeJ, C57BL/6NTacCdh23+ ). The loss of afferent synapses was present in all strains at 15 months. The number of efferent synapses per OHCs, defined as postsynaptic SK2 puncta, was reduced in aged OHCs of all strains apart from C3H mice. Several of the identified changes occurred in aged OHCs from all mouse strains, thus representing a general trait in the pathophysiological progression of age-related hearing loss, possibly aimed at preserving functionality. We have also shown that the mechanoelectrical transduction (MET) current from OHCs of mice harbouring the Cdh23ahl allele is reduced with age, highlighting the possibility that changes in the MET apparatus could play a role in cochlear ageing.

Pediatric Brainstem Gliomas: A Retrospective Study of 180 Patients from the SEER Database.

BACKGROUND/AIMS: Large population-based studies are needed to assess the epidemiology and survival risk factors associated with pediatric brainstem gliomas. This retrospective study explores factors that may influence survival in this population. METHODS: Utilizing the SEER database, the authors retrospectively assessed survival in histologically confirmed brainstem gliomas in patients aged 17 and younger. Survival was described with Kaplan-Meyer curves and multivariate regression analysis. RESULTS: This analysis of 180 cases showed that age (hazard ratio [HR] 1.04, 95% CI 0.96-1.14, p = 0.34), non-white race (HR 1.00, 95% CI 0.35-2.85 p > 0.99), distant or invasive extension of the tumor (HR 0.4, 95% CI 0.08-2.53, p = 0.37), and radiation therapy (HR 1.27, 95% CI 0.52-3.11, p = 0.61) were not associated with decreased survival. High-grade tumor status (HR 8.64, 95% CI 3.49-21.41, p < 0.001) was associated with decreased survival. Partial resection (HR 0.11, 95% CI 0.04-0.30, p < 0.001) and gross-total resection (HR 0.03, 95% CI 0.01-0.14, p < 0.001) were associated with improved survival. CONCLUSIONS: High-grade brainstem gliomas have a worse prognosis. Early diagnosis and surgery appear to be associated with improved survival, while the role of radiation is unclear.

Identification of reversible causes of minority inequity in stroke: severity related to race and socio-economic status.

OBJECTIVES: Previous reports of a higher incidence and risk of stroke in minorities were associated primarily with race and ethnicity, yet the relationship between socio-economic status (SES) and racial disparities in stroke is less well known. We have investigated the effects of SES on the incidence of stroke type and its severity in minorities. METHODS: The clinical and demographic data on 140 patients diagnosed with a stroke in the North Lawndale neighbourhood of Chicago, one of the city's poorest communities, were collected prospectively over a 13-month period and then were retrospectively analysed. RESULTS: Overall, haemorrhagic stroke occurred in 31% of cases, differing from the previously reported haemorrhagic stroke incidence of 15%. When accounting for SES, the incidence of haemorrhagic stroke in the uninsured versus the privately or Medicaid-insured increased to 50%. Uninsured African-American patients experienced even higher rates of haemorrhagic stroke at 55%. CONCLUSIONS: Patients who are uninsured minorities may be at an increased risk for severe strokes. This increase in risk appears to be related to the increased incidence of risk factors and lack of treatment. The lack of funds, care access, and limited education in these patients may be related to their increase in risk factors. This paper identifies potentially reversible environmental and societal factors that can lead to improved outcomes in indigent minority patients.

BAI1 localizes AMPA receptors at the cochlear afferent post-synaptic density and is essential for hearing.

Type I spiral ganglion neurons (SGNs) convey sound information to the central auditory pathway by forming synapses with inner hair cells (IHCs) in the mammalian cochlea. The molecular mechanisms regulating the formation of the post-synaptic density (PSD) in the SGN afferent terminals are still unclear. Here, we demonstrate that brain-specific angiogenesis inhibitor 1 (BAI1) is required for the clustering of AMPA receptors GluR2-4 (glutamate receptors 2-4) at the PSD. Adult Bai1-deficient mice have functional IHCs but fail to transmit information to the SGNs, leading to highly raised hearing thresholds. Despite the almost complete absence of AMPA receptor subunits, the SGN fibers innervating the IHCs do not degenerate. Furthermore, we show that AMPA receptors are still expressed in the cochlea of Bai1-deficient mice, highlighting a role for BAI1 in trafficking or anchoring GluR2-4 to the PSDs. These findings identify molecular and functional mechanisms required for sound encoding at cochlear ribbon synapses.

In vivo contribution of nestin- and GLAST-lineage cells to adult hippocampal neurogenesis.

Radial glia-like cells (RGCs) are the hypothesized source of adult hippocampal neurogenesis. However, the current model of hippocampal neurogenesis does not fully incorporate the in vivo heterogeneity of RGCs. In order to better understand the contribution of different RGC subtypes to adult hippocampal neurogenesis, we employed widely used transgenic lines (Nestin-CreER(T2) and GLAST::CreER(T2) mice) to explore how RGCs contribute to neurogenesis under basal conditions and after stimulation and depletion of neural progenitor cells. We first used these inducible fate-tracking transgenic lines to define the similarities and differences in the contribution of nestin- and GLAST-lineage cells to basal long-term hippocampal neurogenesis. We then explored the ability of nestin- and GLAST-lineage RGCs to contribute to neurogenesis after experimental manipulations that either ablate neurogenesis (i.c.v. application of the anti-mitotic AraC, cytosine-ß-D-arabinofuranoside) or stimulate neurogenesis (wheel running). Interestingly, in both ablation and stimulation experiments, labeled RGCs in GLAST::CreER(T2) mice appear to contribute to neurogenesis, whereas RGCs in Nestin-CreER(T2) mice do not. Finally, using NestinGFP reporter mice, we expanded on previous research by showing that not all RGCs in the adult dentate gyrus subgranular zone express nestin, and therefore RGCs are antigenically heterogeneous. These findings are important for the field, as they allow appropriately conservative interpretation of existing and future data that emerge from these inducible transgenic lines. These findings also raise important questions about the differences between transgenic driver lines, the heterogeneity of RGCs, and the potential differences in progenitor cell behavior between transgenic lines. As these findings highlight the possible differences in the contribution of cells to long-term neurogenesis in vivo, they indicate that the current models of hippocampal neurogenesis should be modified to include RGC lineage heterogeneity.

AAV-mediated rescue of Eps8 expression in vivo restores hair-cell function in a mouse model of recessive deafness.

The transduction of acoustic information by hair cells depends upon mechanosensitive stereociliary bundles that project from their apical surface. Mutations or absence of the stereociliary protein EPS8 cause deafness in humans and mice, respectively. Eps8 knockout mice (Eps8 -/- ) have hair cells with immature stereocilia and fail to become sensory receptors. Here, we show that exogenous delivery of Eps8 using Anc80L65 in P1-P2 Eps8 -/- mice in vivo rescued the hair bundle structure of apical-coil hair cells. Rescued hair bundles correctly localize EPS8, WHIRLIN, MYO15, and BAIAP2L2, and generate normal mechanoelectrical transducer currents. Inner hair cells with normal-looking stereocilia re-expressed adult-like basolateral ion channels (BK and KCNQ4) and have normal exocytosis. The number of hair cells undergoing full recovery was not sufficient to rescue hearing in Eps8 -/- mice. Adeno-associated virus (AAV)-transduction of P3 apical-coil and P1-P2 basal-coil hair cells does not rescue hair cells, nor does Anc80L65-Eps8 delivery in adult Eps8 -/- mice. We propose that AAV-induced gene-base therapy is an efficient strategy to recover the complex hair-cell defects in Eps8 -/- mice. However, this therapeutic approach may need to be performed in utero since, at postnatal ages, Eps8 -/- hair cells appear to have matured or accumulated damage beyond the point of repair.

Novel minimally invasive technique in the treatment of cubital tunnel syndrome.

BACKGROUND: Cubital tunnel syndrome is the second most common entrapment neuropathy of the upper extremity in the United States. Most cases are idiopathic and symptoms consist of a combination of weakness, pain, and sensory disturbances ranging from paresthesias and dysesthesias to numbness or complete anesthesia. The purpose of this study is to report results of a novel, minimally invasive surgical procedure for cubital tunnel syndrome with comparison to existing interventions including full open or endoscopic approaches. METHODS: A total of 41 consecutive patients underwent the procedure, their ages ranged from ages 36 to 81 with an average age of 60.52±12.18 years. The procedure consists of a 1.0-2.0-cm incision with decompression of the ulnar nerve under direct visualization proximally with Metzenbaum scissors as a dilator for distal decompression. Patients were evaluated for improvements in pain, numbness, paresthesias, weakness, and muscle atrophy and was measured utilizing the Gabel/Amadio scale. RESULTS: Fifty-three point two percent (n=25) of patients were found to have excellent outcomes, 36.2% (n=17) had good outcomes, 8.5% (n=4) had fair outcomes, and 2.1% (n=1) had poor outcomes as determined by the Gabel/Amadio scale. The greatest improvement in all patients was the reduction in sensory symptoms: pain, numbness, and paresthesia. There were no operative or postoperative complications. CONCLUSIONS: This novel procedure provided symptom relief comparable to the most effective existing techniques without significant complications, and with rapid recovery and minimal scar formation. The authors assert that this technique demonstrates optimal results for patients with relative ease of adoption for surgeons.

Outpatient and Inpatient Readmission Rates of 1- and 2-Level Anterior Cervical Discectomy and Fusion Surgeries.

OBJECTIVE: This study looks at the various comorbidities and postoperative complications and their impact on readmission rates of patients undergoing outpatient versus inpatient 1- and 2-level anterior cervical discectomy and fusion (ACDF). With increasing costs within the United States medical system, one emerging cost-saving strategy is to evolve traditional inpatient procedures into outpatient same-day surgeries. However, patient safety remains a crucial priority. METHODS: A total of 28,427 patients were analyzed, with 26,368 undergoing inpatient ACDF surgery and 2059 undergoing outpatient ACDF surgery. Age, sex, comorbidities, postoperative complications, readmission rates, and overall financial cost were compared between both cohorts. RESULTS: Data from 28,427 one- and two-level ACDF procedures that were split between inpatient and outpatient were collected. Thirty-day readmission rates were significantly lower in outpatients than inpatients (4% vs. 10.1%, P < 0.001). Inpatients had higher rates of urinary tract infection (2.4% vs. 1.4%), deep vein thrombosis (0.6% vs. 0%), and myocardial infarction (0.2% vs. 0%), whereas outpatients had higher rates of pulmonary embolism (7.7% vs. 0.4%). Outpatients had increased readmission risk with comorbidities of diabetes (odds ratio [OR], 48.93; P < 0.001), smoking (OR, 4.6; P < 0.001), body mass index ≥30 (OR, 2392; P < 0.001). The average cost of outpatient surgery was less than that of inpatient surgery ($7774.8 vs. $7956.75, P = 0.0444). CONCLUSION: This study suggests that in the appropriately selected patients, ACDF can safely be performed in an outpatient setting.

A comparison of readmission and complication rates and charges of inpatient and outpatient multiple-level anterior cervical discectomy and fusion surgeries in the Medicare population.

OBJECTIVE: This study aims to assess the relationship of comorbidities and postoperative complications to rates of readmission for geriatric patients undergoing anterior cervical discectomy and fusion (ACDF) involving more than 2 levels on an inpatient or outpatient basis. With the rising costs of healthcare in the United States, understanding the safety and efficacy of performing common surgical interventions (including ACDF) as outpatient procedures could prove to be of great economic impact.Objective This study aims to assess the effect of comorbidities and postoperative complications on the rates of readmission of geriatric patients undergoing multilevel anterior cervical discectomy and fusion (ACDF) procedures (i.e., ACDF involving 3 or more levels) on an inpatient or outpatient basis. Same-day surgery has been demonstrated to be a safe and cost-effective alternative to the traditional inpatient option for many surgical interventions. With the rising costs of healthcare, understanding the safety and efficacy of performing common surgical interventions as outpatient procedures could prove to be of great economic impact. METHODS: The study population included total of 2492 patients: 2348 inpatients and 144 outpatients having ACDF procedures involving 3 or more levels in the Medicare Standard Analytical Files database. Age, sex, comorbidities, postoperative complications, readmission rates, and surgical procedure charges were compared between both cohorts. For selected variables, logistic regression was used to model odds ratios for various comorbidities against readmission rates for both inpatient and outpatient cohorts. Chi-square tests were also calculated to compare these comorbidities with readmission in each cohort. RESULTS: Overall complication rates within 30 postoperative days were greater for inpatients than for outpatients (44.2% vs 12.5%, p < 0.001). More inpatients developed postoperative urinary tract infection (7.9% vs 0%, p < 0.001), and the inpatient cohort had increased risk of readmission with comorbidities of anemia (OR 1.52, p < 0.001), smoking (OR 2.12, p < 0.001), and BMI ≥ 30 (OR 1.43, p < 0.001). Outpatients had increased risk of readmission with comorbidities of anemia (OR 2.78, p = 0.047), diabetes mellitus type 1 or 2 (OR 3.25, p = 0.033), and BMI ≥ 30 (OR 3.95, p = 0.008). Inpatients also had increased readmission risk with a postoperative complication of surgical site infection (OR 2.38, p < 0.001). The average charges for inpatient multilevel ACDF were significantly higher than for multilevel ACDF performed on an outpatient basis ($12,734.27 vs $12,152.18, p = 0.0019). CONCLUSIONS: This study suggests that ACDF surgery involving 3 or more levels performed as an outpatient procedure in the geriatric population may be associated with lower rates of readmissions, complications, and surgical charges.

Adult intradural intramedullary astrocytomas: a multicenter analysis.

BACKGROUND: Intramedullary tumors constitute approximately 20-30% of all spinal cord tumors and approximately 30-40% of these are astrocytomas. Furthermore, they comprise only about 2-4% of all primary central nervous system (CNS) tumors. Due to their rarity and poor prognosis, large population-based studies are needed to assess the epidemiology and survival risk factors associated with these tumors in the hope of improving outcomes. The authors undertook this retrospective study to explore factors that may influence survival in adult patients with intramedullary astrocytomas. METHODS: Utilizing the Surveillance, Epidemiology, and End Results (SEER) database, a prospective cancer registry, the authors retrospectively assessed survival in histologically confirmed, intramedullary spinal cord astrocytomas in patients 18 years of age and older. Survival was described with Kaplan-Meier curves and multivariate regression analysis was used to assess the association of several variables with survival while controlling for confounding variables. RESULTS: Analysis by multivariate regression of 131 cases showed that increasing age of diagnosis [hazard ratio (HR) 1.52, 95% CI: 1.17-1.99, P=0.001], WHO grade IV classification (HR 8.85, 95% CI: 2.83-27.69, P<0.001), tumor invasiveness (HR 2.94, 95% CI: 1.00-8.64, P=0.047), and sub-total resection (HR 5.80, 95% CI: 1.20-28.03, P=0.029) were associated with statistically significant decreases in survival. CONCLUSIONS: This study suggest that older age, higher WHO grade, tumor invasiveness as well as sub-total resection were all associated with a worse prognosis.

Outpatient and inpatient readmission rates of 3- and 4-level anterior cervical discectomy and fusion surgeries.

OBJECTIVE: With the costs related to the United States medical system constantly rising, efforts are being made to turn traditional inpatient procedures into outpatient same-day surgeries. In this study the authors looked at the various comorbidities and perioperative complications and their impact on readmission rates of patients undergoing outpatient versus inpatient 3- and 4-level anterior cervical discectomy and fusion (ACDF). METHODS: This was a retrospective study of 337 3- and 4- level ACDF procedures in 332 patients (5 patients had both primary and revision surgeries that were included in this total of 337 procedures) between May 2012 and June 2017. In total, 331 procedures were analyzed, as 6 patients were lost to follow-up. Outpatient surgery was performed for 299 procedures (102 4-level procedures and 197 3-level procedures), and inpatient surgery was performed for 32 procedures (11 4-level procedures and 21 3-level procedures). Age, sex, comorbidities, number of fusion levels, pain level, and perioperative complications were compared between both cohorts. RESULTS: Analysis was performed for 331 3- and 4-level ACDF procedures done at 6 different hospitals. The overall 30-day readmission rate was 1.2% (outpatient 3 [1.0%] vs inpatient 1 [3.1%], p = 0.847). Outpatients had increased readmission risk, with comorbidities of coronary artery disease (OR 1.058, p = 0.039), autoimmune disease (OR 1.142, p = 0.006), diabetes (OR 1.056, p = 0.001), and chronic kidney disease (OR 0.933, p = 0.035). Perioperative complications of delirium (OR 2.709, p < 0.001) and surgical site infection (OR 2.709, p < 0.001) were associated with increased risk of 30-day hospital readmission in outpatients compared to inpatients. CONCLUSIONS: This study demonstrates the safety and effectiveness of 3- and 4-level ACDF surgery, although various comorbidities and perioperative complications may lead to higher readmission rates. Patient selection for outpatient 3- and 4-level ACDF cases might play a role in the safety of performing these procedures in the ambulatory setting, but further studies are needed to accurately identify which factors are most pertinent for appropriate selection.

Surgical Approaches and Their Outcomes in the Treatment of Cubital Tunnel Syndrome.

Purpose: This review was undertaken in order to provide an updated summary of the current literature on outcomes for various surgical treatments for cubital tunnel syndrome. Methods: Studies reporting outcomes for surgical treatment of cubital tunnel syndrome were collected through the PubMed database. Study structure, number of participants/procedures, mean follow-up times, scoring scales, and outcomes were collected according to the type of surgery: open decompression, endoscopic decompression, minimal incision, subcutaneous transposition, intramuscular transposition, and submuscular transposition. Results: Our findings indicate varying but comparable levels of success among all surgical techniques reviewed. Many different scoring scales were utilized, limiting direct quantitative comparison between most studies. Discussion: While some studies directly compared two or more techniques, there was rarely a statistically significant difference between groups. In comparisons that did reach statistically significant differences, there were others yet that found no difference in comparing the same techniques. Conclusions: None of the techniques in this review has demonstrated universal superiority above all others, but all appear to be effective in the treatment of cubital tunnel syndrome. The only consensus seems to be that transposition is preferred where the ulnar nerve tends to subluxate either on preoperative or intraoperative examination.

Pediatric Spinal Ependymomas: An Epidemiologic Study.

OBJECTIVE: Pediatric intramedullary spinal cord ependymomas represent a rare central nervous system neoplasm with few available data regarding incidence and outcomes. To this end, large population-based studies are needed to assess the epidemiology and survival risk factors associated with these tumors in the hope of better understanding these tumors as well as improving outcomes. This retrospective study was undertaken to explore factors that may influence survival in pediatric patients with intramedullary spinal cord ependymomas. METHODS: Using the SEER (Surveillance Epidemiology and End Results) database, a prospective cancer registry, we retrospectively assessed survival in histologically confirmed spinal ependymomas in patients 17 years of age and younger. Survival was described with Kaplan-Meier curves, and a multivariate regression analysis was used to assess the association of several variables with survival, controlling for confounding variables. RESULTS: Invasive tumor extension (P < 0.001) was associated with decreased survival, whereas gross total resection (P = 0.028) correlated with better rates of survival. Age, gender, tumor size, tumor extension, the use and sequence of radiation therapy, or use of chemotherapy were not found to have a statistically significant association with survival outcomes. CONCLUSIONS: Invasive ependymomas occurring in the spine have a worse prognosis, whereas higher tumor grades do not clearly show worse rates of survival. Early diagnosis and surgery seem to be associated with improved survival and outcomes, whereas radiation therapy and chemotherapy have an unclear role.