Immune Predictors of Mortality After Ribonucleic Acid Virus Infection

BACKGROUND

Virus infections result in a range of clinical outcomes for the host, from asymptomatic to severe or even lethal disease. Despite global efforts to prevent and treat virus infections to limit morbidity and mortality, the continued emergence and re-emergence of new outbreaks as well as common infections such as influenza persist as a health threat. Challenges to the prevention of severe disease after virus infection include both a paucity of protective vaccines as well as the early identification of individuals with the highest risk that may require supportive treatment.

METHODS

We completed a screen of mice from the Collaborative Cross (CC) that we infected with influenza, severe acute respiratory syndrome-coronavirus, and West Nile virus.

RESULTS

The CC mice exhibited a range of disease manifestations upon infections, and we used this natural variation to identify strains with mortality after infection and strains exhibiting no mortality. We then used comprehensive preinfection immunophenotyping to identify global baseline immune correlates of protection from mortality to virus infection.

CONCLUSIONS

These data suggest that immune phenotypes might be leveraged to identify humans at highest risk of adverse clinical outcomes upon infection, who may most benefit from intensive clinical interventions, in addition to providing insight for rational vaccine design.

Cost Transparency in Neurosurgery: A Single-Institution Analysis of Patient Out-of-Pocket Spending in 13 673 Consecutive Neurosurgery Cases

BACKGROUND

Patient out-of-pocket (OOP) spending is an increasingly discussed topic; however, there is minimal data available on the patient financial burden of surgical procedures.

OBJECTIVE

To analyze hospital and surgeon expected payment data and patient OOP spending in neurosurgery.

METHODS

This is a retrospective cohort study of neurosurgical patients at a tertiary-referral center from 2013 to 2016. Expected payments, reflecting negotiated costs-of-care, as well as actual patient OOP payments for hospital care and surgeon professional fees were analyzed. A 4-tiered model of patient OOP cost sharing and a multivariate model of patient expected payments were created.

RESULTS

A total of 13 673 consecutive neurosurgical cases were analyzed. Patient age, insurance type, case category, severity of illness, length of stay (LOS), and elective case status were significant predictors of increased expected payments (P < .05). Craniotomy ($53 397 ± 811) and posterior spinal fusion ($48 329 ± 864) were associated with the highest expected payments. In a model of patient OOP cost sharing, nearly all neurosurgical procedures exceeded yearly OOP maximums for Healthcare Marketplace plans. Mean patient payments for hospital care and surgeon professional fees were the highest for anterior/lateral spinal fusion cases for commercially insured patients ($1662 ± 165). Mean expected payments and mean patient payments for commercially insured patients increased significantly from 2013 to 2016 (P < .05).

CONCLUSION

Expected payments and patient OOP spending for commercially insured patients significantly increased from 2013 to 2016, representing increased healthcare costs and patient cost sharing in an evolving healthcare environment. Patients and providers can consider this information prior to surgery to better anticipate the individual financial burden for neurosurgical care.

Anterior Cerebral Artery Bypass for Complex Aneurysms: Advances in Intracranial-Intracranial Bypass Techniques

BACKGROUND

Anterior cerebral artery (ACA) bypasses for complex aneurysms are infrequently performed, yet previous experience demonstrates the importance of intracranial-intracranial bypasses. Here we describe technical advances in intracranial-intracranial bypass techniques and their clinical results.

METHODS

Twenty-three patients with complex aneurysms requiring ACA bypasses were retrospectively studied. Ten patients were treated in period 1 (1997-2013) and 13 in period 2 (2014-2018).

RESULTS

There were 3 precommunicating, 8 communicating, and 8 postcommunicating ACA aneurysms, plus 4 middle cerebral artery aneurysms. ACA in situ bypass was the most commonly performed (9 patients; 39%). The classic left A3 ACA-right A3 ACA in situ bypass was performed in 5 patients, but 3 new in situ variations emerged in period 2: left pericallosal artery (PcaA)-right PcaA (n = 1), left callosomarginal artery (CmaA)-right CmaA (n = 2), and left CmaA-right A3 ACA (n = 1). The sole reimplantation in period 1 was the ipsilateral and vertical PcaA-CmaA reimplantation, whereas reimplantations in period 2 were contralateral and horizontal (left PcaA-right PcaA and right A3 ACA-left anterior internal frontal artery). The A1 ACA was used as a donor only in period 2 in 4 patients with middle cerebral artery bifurcation aneurysms. Bypass patency was 91%, and 21 patients (91%) improved or remained at neurologic baseline (mean [standard deviation] follow-up duration, 26 [8.2] months).

CONCLUSIONS

ACA bypass techniques continue to evolve with the addition of several variations. These variations push bypass techniques beyond the standard constructs and add important alternatives to our bypass arsenal.

Combining Stereoscopic Video and Virtual Reality Simulation to Maximize Education in Lateral Skull Base Surgery

Mastery of lateral skull base (LSB) surgery requires thorough knowledge of complex, 3-dimensional (3D) microanatomy and techniques. While supervised operation under binocular microscopy remains the training gold standard, concerns over operative time and patient safety often limit novice surgeons’ stereoscopic exposure. Furthermore, most alternative educational resources cannot meet this need. Here we present proof of concept for a tool that combines 3D-operative video with an interactive, stereotactic teaching environment. Stereoscopic video was recorded with a microscope during translabyrinthine approaches for vestibular schwannoma. Digital imaging and communications in medicine (DICOM) temporal bone computed tomography images were segmented using 3D-Slicer. Files were rendered using a game engine software built for desktop virtual reality. The resulting simulation was an interactive immersion combining a 3D operative perspective from the lead surgeon’s chair with virtual reality temporal bone models capable of hands-on manipulation, label toggling, and transparency modification. This novel tool may alter LSB training paradigms.

Polygenic Risk Score-Derived Subcortical Connectivity Mediates Attention-Deficit/Hyperactivity Disorder Diagnosis

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) has substantial heritability, and a recent large-scale investigation has identified common genome-wide significant loci associated with increased risk for ADHD. Along the same lines, many studies using noninvasive neuroimaging have identified differences in brain functional connectivity in children with ADHD. We attempted to bridge these studies to identify differences in functional connectivity associated with common genetic risk for ADHD using polygenic risk score (PRS).

METHODS

We computed ADHD PRSs for all participants in our sample (N = 315, children 7-13 years of age, 196 with ADHD and 119 unaffected comparison children) using ADHD data from the Psychiatric Genomics Consortium as a discovery set. Magnetic resonance imaging was used to evaluate resting-state functional connectivity of targeted subcortical structures.

RESULTS

The functional connectivity between 2 region pairs demonstrated a significant correlation to PRS: right caudate-parietal cortex and nucleus accumbens-occipital cortex. Connectivity between these areas, in addition to being correlated with PRS, was correlated with ADHD status. The connection between the caudate and the parietal region acted as a statistical suppressor, such that when it was included in a path model, the association between PRS and ADHD status was enhanced.

CONCLUSIONS

Our results suggest that functional connectivity to certain subcortical brain regions is directly altered by genetic variants, and certain cortico-subcortical connections may modulate ADHD-related genetic effects.

Endoscope-Assisted, Transmastoid, High Cervical Approach for Resection of a Jugular Foramen Schwannoma: 2-Dimensional Operative Video

Jugular foramen schwannomas (JFSs) are relatively rare, benign lesions that account for 10% to 30% of all tumors in the region of the jugular foramen. Given their slow-growing nature, JFSs can become quite large before causing symptoms of lower cranial nerve (LCN) dysfunction, making microsurgical resection a challenge. Successful resection of any JFS is dependent on the identification and preservation of the adjacent, uninvolved LCNs to alleviate nerve compression and preserve function. We report a transmastoid, high cervical approach to a dumbbell-shaped, extracranial JFS that was causing symptomatic LCN compression. The patient presented with dysphagia and was found to have left vocal cord paralysis on video laryngoscopy and intermittent aspiration on a swallowing evaluation. The transmastoid, high cervical exposure allowed for early identification of the tumor as well as the adjacent LCNs. Neurophysiological monitoring included somatosensory evoked potentials; brainstem auditory evoked responses; and cranial nerve VII, X, XI, and XII electromyographic monitoring. Endoscopic assistance allowed for improved LCN visualization from the high cervical exposure and gross-total resection of the tumor. The patient's dysphagia improved both subjectively and objectively following the resection. The patient gave written informed consent for surgery and publication of the case report. Institutional review board approval was not required for this case report. Used with permission from Barrow Neurological Institute.

Three-Dimensional Printed Models for Lateral Skull Base Surgical Training: Anatomy and Simulation of the Transtemporal Approaches

BACKGROUND

Three-dimensional (3D) printing holds great potential for lateral skull base surgical training; however, studies evaluating the use of 3D-printed models for simulating transtemporal approaches are lacking.

OBJECTIVE

To develop and evaluate a 3D-printed model that accurately represents the anatomic relationships, surgical corridor, and surgical working angles achieved with increasingly aggressive temporal bone resection in lateral skull base approaches.

METHODS

Cadaveric temporal bones underwent thin-slice computerized tomography, and key anatomic landmarks were segmented using 3D imaging software. Corresponding 3D-printed temporal bone models were created, and 4 stages of increasingly aggressive transtemporal approaches were performed (40 total approaches). The surgical exposure and working corridor were analyzed quantitatively, and measures of face validity, content validity, and construct validity in a cohort of 14 participants were assessed.

RESULTS

Stereotactic measurements of the surgical angle of approach to the mid-clivus, residual bone angle, and 3D-scanned infill volume demonstrated comparable changes in both the 3D temporal bone models and cadaveric specimens based on the increasing stages of transtemporal approaches (PANOVA <.003, <.007, and <.007, respectively), indicating accurate representation of the surgical corridor and working angles in the 3D-printed models. Participant assessment revealed high face validity, content validity, and construct validity.

CONCLUSION

The 3D-printed temporal bone models highlighting key anatomic structures accurately simulated 4 sequential stages of transtemporal approaches with high face validity, content validity, and construct validity. This strategy may provide a useful educational resource for temporal bone anatomy and training in lateral skull base approaches.

Evaluating chronic emotional dysregulation and irritability in relation to ADHD and depression genetic risk in children with ADHD

BACKGROUND

A central nosological problem concerns the etiological relationship of emotional dysregulation with ADHD. Molecular genetic risk scores provide a novel method for informing this question.

METHODS

Participants were 514 community-recruited children of Northern European descent age 7-11 defined as ADHD or non-ADHD by detailed research evaluation. Parents-rated ADHD on standardized ratings and child temperament on the Temperament in Middle Childhood Questionnaire (TMCQ) and reported on ADHD and comorbid disorders by semi-structured clinical interview. Categorical and dimensional variables were created for ADHD, emotional dysregulation (implicating disruption of regulation of both anger-irritability and of positive valence surgency-sensation seeking), and irritability alone (anger dysregulation). Genome-wide polygenic risk scores (PRS) were computed for ADHD and depression genetic liability. Structural equation models and computationally derived emotion profiles guided analysis.

RESULTS

The ADHD PRS was associated in variable-centered analyses with irritability (β = .179, 95% CI = 0.087-0.280; ΔR²  = .034, p < .0002), but also with surgency/sensation seeking (B = .146, 95%CI = 0.052-0.240, ΔR² =.022, p = .002). In person-centered analysis, the ADHD PRS was elevated in the emotion dysregulation ADHD group versus other ADHD children (OR = 1.44, 95% CI = 1.03-2.20, Nagelkerke ΔR²  = .013, p = .033) but did not differentiate irritable from surgent ADHD profiles. All effects were independent of variation in ADHD severity across traits or groups. The depression PRS was related to oppositional defiant disorder but not to ADHD emotion dysregulation.

CONCLUSIONS

Irritability-anger and surgency-sensation seeking, as forms of negative and positively valenced dysregulated affect in ADHD populations, both relate principally to ADHD genetic risk and not mood-related genetic risk.

Large epigenome-wide association study of childhood ADHD identifies peripheral DNA methylation associated with disease and polygenic risk burden

Epigenetic variation in peripheral tissues is being widely studied as a molecular biomarker of complex disease and disease-related exposures. To date, few studies have examined differences in DNA methylation associated with attention-deficit hyperactivity disorder (ADHD). In this study, we profiled genetic and methylomic variation across the genome in saliva samples from children (age 7-12 years) with clinically established ADHD (N = 391) and nonpsychiatric controls (N = 213). We tested for differentially methylated positions (DMPs) associated with both ADHD diagnosis and ADHD polygenic risk score, by using linear regression models including smoking, medication effects, and other potential confounders in our statistical models. Our results support previously reported associations between ADHD and DNA methylation levels at sites annotated to VIPR2, and identify several novel disease-associated DMPs (p < 1e-5), although none of them were genome-wide significant. The two top-ranked, ADHD-associated DMPs (cg17478313 annotated to SLC7A8 and cg21609804 annotated to MARK2) are also significantly associated with nearby SNPs (p = 1.2e-46 and p = 2.07e-59), providing evidence that disease-associated DMPs are under genetic control. We also report a genome-wide significant association between ADHD polygenic risk and variable DNA methylation at a site annotated to the promoter of GART and SON (p = 6.71E-8). Finally, we show that ADHD-associated SNPs colocalize with SNPs associated with methylation levels in saliva. This is the first large-scale study of DNA methylation in children with ADHD. Our results represent novel epigenetic biomarkers for ADHD that may be useful for patient stratification, reinforce the importance of genetic effects on DNA methylation, and provide plausible molecular mechanisms for ADHD risk variants.

Anatomical assessment of trigeminal nerve tractography using diffusion MRI: A comparison of acquisition b-values and single- and multi-fiber tracking strategies

•

Investigation of the performance of multiple dMRI acquisitions and fiber models for trigeminal nerve (TGN) identification.

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Expert rating study of over 1000 TGN visualizations using seven proposed expert rating anatomical criteria.

•

The two-tensor tractography method had better performance on identifying true positive structures, while generating more false positive streamlines in comparison to the single-tensor tractography method.

•

TGN tracking performance was significantly different across the three b-values for almost all structures studied.

Background

The trigeminal nerve (TGN) is the largest cranial nerve and can be involved in multiple inflammatory, compressive, ischemic or other pathologies. Currently, imaging-based approaches to identify the TGN mostly rely on T2-weighted magnetic resonance imaging (MRI), which provides localization of the cisternal portion of the TGN where the contrast between nerve and cerebrospinal fluid (CSF) is high enough to allow differentiation. The course of the TGN within the brainstem as well as anterior to the cisternal portion, however, is more difficult to display on traditional imaging sequences. An advanced imaging technique, diffusion MRI (dMRI), enables tracking of the trajectory of TGN fibers and has the potential to visualize anatomical regions of the TGN not seen on T2-weighted imaging. This may allow a more comprehensive assessment of the nerve in the context of pathology. To date, most work in TGN tracking has used clinical dMRI acquisitions with a b-value of 1000 s/mm² and conventional diffusion tensor MRI (DTI) tractography methods. Though higher b-value acquisitions and multi-tensor tractography methods are known to be beneficial for tracking brain white matter fiber tracts, there have been no studies conducted to evaluate the performance of these advanced approaches on nerve tracking of the TGN, in particular on tracking different anatomical regions of the TGN.

Objective

We compare TGN tracking performance using dMRI data with different b-values, in combination with both single- and multi-tensor tractography methods. Our goal is to assess the advantages and limitations of these different strategies for identifying the anatomical regions of the TGN.

Methods

We proposed seven anatomical rating criteria including true and false positive structures, and we performed an expert rating study of over 1000 TGN visualizations, as follows. We tracked the TGN using high-quality dMRI data from 100 healthy adult subjects from the Human Connectome Project (HCP). TGN tracking performance was compared across dMRI acquisitions with b = 1000 s/mm², b = 2000 s/mm² and b = 3000 s/mm², using single-tensor (1T) and two-tensor (2T) unscented Kalman filter (UKF) tractography. This resulted in a total of six tracking strategies. The TGN was identified using an anatomical region-of-interest (ROI) selection approach. First, in a subset of the dataset we identified ROIs that provided good TGN tracking performance across all tracking strategies. Using these ROIs, the TGN was then tracked in all subjects using the six tracking strategies. An expert rater (GX) visually assessed and scored each TGN based on seven anatomical judgment criteria. These criteria included the presence of multiple expected anatomical segments of the TGN (true positive structures), specifically branch-like structures, cisternal portion, mesencephalic trigeminal tract, and spinal cord tract of the TGN. False positive criteria included the presence of any fibers entering the temporal lobe, the inferior cerebellar peduncle, or the middle cerebellar peduncle. Expert rating scores were analyzed to compare TGN tracking performance across the six tracking strategies. Intra- and inter-rater validation was performed to assess the reliability of the expert TGN rating result.

Results

The TGN was selected using two anatomical ROIs (Meckel's Cave and cisternal portion of the TGN). The two-tensor tractography method had significantly better performance on identifying true positive structures, while generating more false positive streamlines in comparison to the single-tensor tractography method. TGN tracking performance was significantly different across the three b-values for almost all structures studied. Tracking performance was reported in terms of the percentage of subjects achieving each anatomical rating criterion. Tracking of the cisternal portion and branching structure of the TGN was generally successful, with the highest performance of over 98% using two-tensor tractography and b = 1000 or b = 2000. However, tracking the smaller mesencephalic and spinal cord tracts of the TGN was quite challenging (highest performance of 37.5% and 57.07%, using two-tensor tractography with b = 1000 and b = 2000, respectively). False positive connections to the temporal lobe (over 38% of subjects for all strategies) and cerebellar peduncles (100% of subjects for all strategies) were prevalent. High joint probability of agreement was obtained in the inter-rater (on average 83%) and intra-rater validation (on average 90%), showing a highly reliable expert rating result.

Conclusions

Overall, the results of the study suggest that researchers and clinicians may benefit from tailoring their acquisition and tracking methodology to the specific anatomical portion of the TGN that is of the greatest interest. For example, tracking of branching structures and TGN-T2 overlap can be best achieved with a two-tensor model and an acquisition using b = 1000 or b = 2000. In general, b = 1000 and b = 2000 acquisitions provided the best-rated tracking results. Further research is needed to improve both sensitivity and specificity of the depiction of the TGN anatomy using dMRI.

Posterior Petrosal Transotic Approach for Cerebellopontine Angle Hemangioblastoma: Technical Case Report

BACKGROUND AND IMPORTANCE

Although posterior petrosal approaches are utilized less frequently in many practices today, they continue to provide distinct surgical advantages in carefully selected cases. Here, we report a case of a recurrent cerebellopontine angle (CPA) hemangioblastoma that had failed a prior, more conservative, surgical approach. We provide cadaveric dissections of variations of posterior petrosal approaches to illustrate the advantages of the selected approach.

CLINICAL PRESENTATION

A 70-yr-old female presented with a growing left CPA hemangioblastoma. The lesion had undergone a prior subtotal resection from a retrosigmoid approach and subsequent adjuvant radiation treatment. The patient had worsening left facial strength, progressive balance difficulty, and absent left auditory function. Preoperative angiogram demonstrated arterial blood supply from the left anterior inferior cerebellar artery (AICA) that was deemed unsafe for embolization due to significant arteriovenous shunting. A posterior petrosal transotic approach was performed in order to optimize the working angle to the anterior brainstem and afford the ability to occlude the vascular supply from AICA prior to surgical resection of the lesion.

CONCLUSION

The posterior petrosal transotic approach offers an improved surgical working angle to the anterior brainstem compared to the translabyrinthine approach. This advantage can be particularly important with vascular tumors that receive blood supply anteriorly, as in this case from AICA, and can improve the safety of the resection.

Brachytherapy with surgical resection as salvage treatment for recurrent high-grade meningiomas: a matched cohort study

PURPOSE

To evaluate surgical resection with brachytherapy placement as a salvage treatment in patients with recurrent high-grade meningioma who exhausted prior external beam treatment options.

METHODS

Single-center retrospective review of our institutional experience of brachytherapy implantation from 2012 to 2018. The primary outcome of the study was progression free survival (PFS). Secondary outcomes included overall survival (OS) and complications. A matched cohort of patients not treated with brachytherapy over the same time period was evaluated as a control group. All patients had received prior radiation treatment and underwent planned gross total resection (GTR) surgery.

RESULTS

A total of 27 cases were evaluated. Compared with prior treatment, brachytherapy implantation demonstrated a statistically significant improvement in tumor control [HR 0.316 (0.101 - 0.991), p = 0.034]. PFS-6 and PFS-12 were 92.3% and 84.6%, respectively. Compared with the matched control cohort, brachytherapy treatment demonstrated improved PFS [HR 0.310 (0.103 - 0.933), p = 0.030]. Overall survival was not statistically significantly different between groups [HR 0.381 (0.073 - 1.982), p = 0.227]. Overall postoperative complications were comparable between groups, although there was a higher incidence of radiation necrosis in the brachytherapy cohort.

CONCLUSION

Brachytherapy with planned GTR improved PFS in recurrent high-grade meningioma patients who exhausted prior external beam radiation treatment options. Future improvement of brachytherapy dose delivery methods and techniques may continue to prolong control rates and improve outcomes for this challenging group of patients.

Pedicled Vascularized Bone Grafts for Posterior Occipitocervical and Cervicothoracic Fusion: A Cadaveric Feasibility Study

BACKGROUND

Arthrodesis is critical for achieving favorable outcomes in reconstructive spine surgery. Vascularized bone grafts (VBGs) have been successfully used to augment fusion rates in a variety of skeletal pathologies, and pedicled VBG has numerous advantages over free transfer VBG. Pedicled VBG has not previously been described for the posterior occipitocervicothoracic spine.

OBJECTIVE

To identify, describe, and assess potential donor sites for pedicled VBGs from occiput to T12 using a cadaver model and to describe important technical considerations for graft harvest and placement.

METHODS

A multidisciplinary team of plastic surgeons and neurosurgeons hypothesized that it is feasible to rotate a pedicled VBG from the occiput to T12 via a posterior approach. In 6 cadavers, 3 VBG donor sites were identified as anatomically feasible: occiput, scapula, and rib.

RESULTS

Split- and full-thickness occipital VBGs were mobilized on a semispinalis pedicle. Occipital VBGs could be mobilized from occiput to T1 and span up to 4 levels. Scapular VBGs were mobilized on a subscapular pedicle and could be mobilized from occiput to T7 and span up to 8 levels. Rib VBGs were mobilized on subcostal pedicles and could be mobilized from C6 to T12. Ribs T2 to T4 and T11 and T12 could cover 2 levels, and ribs T5 to T10 could cover 3 levels. The first rib was anatomically unsuitable as a VBG due to its primarily ventral course.

CONCLUSION

Pedicled VBGs can feasibly be applied to posterior spinal arthrodesis from occiput to T12. Patients at high risk for nonunion may benefit from this strategy.

Comparison of Surgical Outcomes and Recurrence Rates of Cystic and Solid Vestibular Schwannomas

Objective  Cystic vestibular schwannomas (CVSs) are anecdotally believed to have worse clinical and tumor-control outcomes than solid vestibular schwannomas (SVSs); however, no data have been reported to support this belief. In this study, we characterize the clinical outcomes of patients with CVSs versus those with SVSs. Design  This is a retrospective review of prospectively collected data. Setting  This study is set at single high-volume neurosurgical institute. Participants  We queried a database for details on all patients diagnosed with vestibular schwannomas between January 2009 and January 2014. Main Outcome Measures  Records were retrospectively reviewed and analyzed using univariate and multivariate analyses to study the differences in clinical outcomes and tumor progression or recurrence. Results  Of a total of 112 tumors, 24% ( n  = 27) were CVSs and 76% ( n  = 85) were SVSs. Univariate analysis identified the extent of resection, Koos grade, and tumor diameter as significant predictors of recurrence ( p  ≤ 0.005). However, tumor diameter was the only significant predictor of recurrence in the multivariate analysis ( p  = 0.007). Cystic change was not a predictor of recurrence in the univariate or multivariate analysis ( p  ≥ 0.40). Postoperative facial nerve and hearing outcomes were similar for both CVSs and SVSs ( p  ≥ 0.47). Conclusion  Postoperative facial nerve outcome, hearing, tumor progression, and recurrence are similar for patients with CVSs and SVSs. As CVS growth patterns and responses to radiation are unpredictable, we favor microsurgical resection over radiosurgery as the initial treatment. Our data do not support the commonly held belief that cystic tumors behave more aggressively than solid tumors or are associated with increased postoperative facial nerve deficits.

Clinical, pathologic, and imaging characteristics of pituitary null cell adenomas as defined according to the 2017 World Health Organization criteria: a case series from two pituitary centers

PURPOSE

The 2017 World Health Organization classification of pituitary tumors redefined pituitary null cell adenomas (NCAs) by restricting this diagnostic category to pituitary tumors that are negative for pituitary transcription factors and adenohypophyseal hormones. The clinical behavior of this redefined entity has not been widely studied, and this is a major shortcoming of the classification. This study evaluated the imaging and clinical features of NCAs from two pituitary centers and compared them with those of gonadotroph adenomas (GAs).

METHODS

Imaging, pathologic, and clinical characteristics of NCAs and GAs were retrospectively reviewed. Tumor immunohistochemistry was performed to confirm absence of adenohypophyseal hormones and pituitary transcription factor expression.

RESULTS

Thirty-one NCAs were compared with 38 GAs. NCAs were more likely to invade the cavernous sinus (15/31 [48%] vs. 5/38 [13%], P = .003) and had a higher proliferative index (i.e., MIB-1 > 3%, 11/31 [35%] vs. 5/38 [13%], P = .04). Gross total resection was less likely in the NCA group (19/31 [61%] vs. 33/38 [87], P = .02). Progression-free survival was worse in the NCA cohort (5-year progression-free survival, 0.70 vs. 1.00; P = .011, by log-rank test).

CONCLUSIONS

Compared with GAs, NCAs are more invasive at the time of presentation and have a more aggressive clinical course. This study provides evidence that NCAs represent a distinct clinicopathologic entity with behavior that differs adversely from that of GAs. This may inform clinical decision-making, including frequency of postoperative tumor surveillance and timing of adjunctive treatments.

Overlapping Surgeries Are Not Associated With Worse Patient Outcomes: Retrospective Multivariate Analysis of 14 872 Neurosurgical Cases Performed at a Single Institution

BACKGROUND

Overlapping surgeries have recently become a controversial topic.

OBJECTIVE

To evaluate the effect of overlapping surgeries on patient outcomes.

METHODS

A retrospective analysis of all neurosurgical procedures performed at a single institution from July 2013 to May 2016 was conducted. Variables extracted from the electronic medical records included sex, age, procedure type, resident years of training, evening case, emergency case, American Society of Anesthesiologists Physical Status Score, illness severity, mortality risk, and percentage of case overlap. Univariate and multivariate analyses were performed for the following primary outcomes: procedure length, length of hospital stay, return to operating room (OR), disposition upon discharge, hospital readmission, and mortality. Separate analyses were performed for overlap thresholds of 0%, 20%, 50%, and 100%.

RESULTS

A total of 14 872 cases were performed during the study period, and all were included in the statistical analyses. Univariate analysis showed a benefit for overlapping surgeries in terms of hospital length of stay, return to OR, and disposition status (all P < .001). No difference was found for hospital readmission or mortality. Overlapping surgeries were significantly longer and were staffed by more senior residents (P < .001). Multivariate analysis showed a benefit for overlapping surgeries, or no difference, for all the measured outcomes except procedure length.

CONCLUSION

These results reject the hypothesis that overlapping surgeries are predictive of worse outcomes. When considered in the context of the current debate regarding overlapping surgeries, these results argue against claims that overlapping surgeries are dangerous or harmful to patients.

The Barrow Biomimetic Spine: Face, Content, and Construct Validity of a 3D-Printed Spine Model for Freehand and Minimally Invasive Pedicle Screw Insertion

STUDY DESIGN

Description and evaluation of a novel surgical training platform.

OBJECTIVES

The purpose of this study was to investigate the face, content, and construct validity of 5 novel surgical training models that simulate freehand and percutaneous (minimally invasive surgery [MIS]) pedicle screw placement.

METHODS

Five spine models were developed by residents: 3 for freehand pedicle screw training (models A-C) and 2 for MIS pedicle screw training (models D and E). Attending spine surgeons evaluated each model and, using a 20-point Likert-type scale, answered survey questions on model face, content, and construct validity. Scores were statistically evaluated and compared using means, standard deviations, and analysis of variance between models and between surgeons.

RESULTS

Among the freehand models, model C demonstrated the highest overall validity, with mean face (15.67 ± 5.49), content (19.17 ± 0.59), and construct (18.83 ± 0.24) validity all measuring higher than the other freehand models. For the MIS models, model D had the highest validity scores (face, content, and construct validity of 11.67 ± 3.77, 18.17 ± 2.04, and 17.00 ± 3.46, respectively). The 3 freehand models differed significantly in content validity scores (P = .002) as did the 2 MIS models (P < .001). The testing surgeons' overall validity scores were significantly different for models A (P = .005) and E (P < .001).

CONCLUSIONS

A 3-dimensional-printed spine model with incorporated bone bleeding and silicone rubber soft tissue was scored as having very high content and construct validity for simulating freehand pedicle screw insertion. These data has informed the further development of several surgical training models that hold great potential as educational adjuncts in surgical training programs.

Disc Geometry is an Accurate Predictor of Lordotic Correction in the Thoracolumbar Spine Following Schwab Grade 2 Osteotomy: A Cadaveric Study and Biomechanical Analysis of Disc Space Changes Following Lordotic Correction

BACKGROUND

Posterior column osteotomy (PCO) is a powerful technique for correcting lordosis, but the surgical literature lacks objective evidence on preoperative predictors of achievable lordotic correction following PCO.

OBJECTIVE

To measure the correlation between disc geometry and achievable lordotic correction following Schwab grade 2 osteotomies and to describe geometric changes to disc space following lordotic correction.

METHODS

Schwab grade 2 osteotomies were performed from T1 to S1 in 5 cadavers. Lateral radiographs were taken before and after posterior column compression. Anterior disc height (ADH), middle disc height (MDH), posterior disc height (PDH), and lordotic angles were measured. The association between disc height and lordotic correction was analyzed using linear regression.

RESULTS

For all spinal levels (n = 79), PDH was most strongly correlated with lordotic correction (r = 0.72, P < .001). Regional subset analyses showed the strongest correlation between PDH and lordotic correction achievable within the lumbar spine (n = 22, r = 0.77, P < .001), followed by ADH for lower thoracic spine (n = 29, r = 0.65, P < .001) and PDH for upper thoracic spine (n = 28, r = 0.61, P = .001). Postcorrection analysis of disc heights revealed that as lordotic correction increases, the PDH decreases, and the ADH expands.

CONCLUSION

PDH is a strong predictor of achievable lordotic correction following Schwab grade 2 osteotomies and compression of an intact disc space. In the lumbar spine, 50% of lordotic change is predictable using PDH alone. Further testing of our linear regression equation is planned for prospective clinical studies, and further testing of postcorrection disc space geometry is planned for future biomechanical and surgical technique studies.

The Prognostic Significance of a Cast Fourth Ventricle in Ruptured Aneurysm Patients With Intraventricular Hemorrhage in the Barrow Ruptured Aneurysm Trial (BRAT)

BACKGROUND

Ruptured aneurysms causing intraventricular hemorrhage (IVH) are associated with high morbidity. The presence of blood that completely fills the fourth ventricle (cast fourth ventricle, CFV) is thought to be particularly ominous, but studies documenting the outcome of such cases are lacking.

OBJECTIVE

To investigate the outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH) and CFV.

METHODS

We reviewed 406 patients enrolled in the Barrow Ruptured Aneurysm Trial (BRAT, NCT01593267, clinicaltrials.gov); 238 patients with aSAH and IVH were identified, and imaging was reviewed for the presence of CFV. Outcome was evaluated at the 1-yr follow-up. A poor outcome was defined as modified Rankin Scale score >2.

RESULTS

CFV was identified in 25 patients. Admission Glasgow Coma Score was lower in CFV patients, 7.8 versus 11.5 (P < .001). At discharge and the 1-yr follow-up, patients with CFV had a greater risk of a poor outcome (P < .001 and P = .002, respectively). In a subgroup analysis of 79 patients with IVH and initial Glasgow Coma Score ≤ 8, almost 50% of the patients with IVH but without CFV had made a good recovery versus 7% of patients with CFV (odds ratio [OR] 15, P = .002). On multivariate analysis, CFV was a greater predictor of a poor prognosis at 1 yr post-aSAH than Hunt and Hess grade >3 (6.4 OR vs 2.9 OR [P < .001], respectively).

CONCLUSION

The presence of CFV is a predictor of poor outcome in patients with aSAH. When compared to other patients with IVH and aSAH, CFV is a stronger predictor of a poor outcome than a poor Hunt and Hess Grade.

Evaluation of Surgical Resection Goal and Its Relationship to Extent of Resection and Patient Outcomes in a Multicenter Prospective Study of Patients With Surgically Treated, Nonfunctioning Pituitary Adenomas: A Case Series

BACKGROUND

The influence of the surgeon's preoperative goal regarding the extent of tumor resection on patient outcomes has not been carefully studied among patients with nonfunctioning pituitary adenomas.

OBJECTIVE

To analyze the relationship between surgical tumor removal goal and patient outcomes in a prospective multicenter study.

METHODS

Centrally adjudicated extent of tumor resection (gross total resection [GTR] and subtotal resection [STR]) data were analyzed using standard univariate and multivariable analyses.

RESULTS

GTR was accomplished in 148 of 171 (86.5%) patients with planned GTR and 32 of 50 (64.0%) patients with planned STR (P = .001). Sensitivity, specificity, positive predictive value, and negative predictive value of GTR goal were 82.2, 43.9, 86.5, and 36.0%, respectively. Knosp grade 0-2, first surgery, and being an experienced surgeon were associated with surgeons choosing GTR as the goal (P &lt; .01). There was no association between surgical goal and presence of pituitary deficiency at 6 mo (P = .31). Tumor Knosp grade (P = .004) and size (P = .001) were stronger predictors of GTR than was surgical goal (P = .014). The most common site of residual tumor was the cavernous sinus (29 of 41 patients; 70.1%).

CONCLUSION

This is the first pituitary surgery study to examine surgical goal regarding extent of tumor resection and associated patient outcomes. Surgical goal is a poor predictor of actual tumor resection. A more aggressive surgical goal does not correlate with pituitary gland dysfunction. A better understanding of the ability of surgeons to meet their expectations and of the factors associated with surgical result should improve prognostication and preoperative counseling.

Accuracy in Deep Brain Stimulation Electrode Placement: A Single-Surgeon Retrospective Analysis of Sterotactic Error in Overlapping and Non-Overlapping Surgical Cases

BACKGROUND

Many surgeons utilize assistants to perform procedures in more than one operating room at a given time using a practice known as overlapping surgery. Debate has continued as to whether overlapping surgery improves the efficiency and access to care or risks patient safety and outcomes.

OBJECTIVE

To examine effects of overlapping surgery in deep brain stimulation (DBS) for movement disorders.

METHODS

In this retrospective analysis of overlapping and non-overlapping cases, we evaluated stereotactic accuracy, operative duration, length of hospital stay, and the presence of hemorrhage, wound-related complications, and hardware-related complications requiring revision in adults with movement disorders undergoing DBS.

RESULTS

Of 324 cases, 141 (43.5%) were overlapping and 183 (56.5%) non-overlapping. Stereotactic error, number of brain penetrations, and postoperative length of hospitalization did not differ significantly (p ≥ 0.08) between the overlapping and non-overlapping groups. Mean operative duration was significantly longer for overlapping (81/141 [57.4%], 189.5 ± 10.8 min) than for non-overlapping cases (79/183 [43.2%], 169.9 ± 7.6 min; p = 0.004). There were no differences in rates of wound-related complications or hemorrhages, but overlapping cases had a significantly higher rate of hardware-related complications requiring revision (7/141 [5.0%] vs. 0/183 [0%]; p = 0.002).

CONCLUSIONS

Overlapping and non-overlapping cases had comparable DBS lead placement accuracy. Overlapping cases had a longer operative duration and had a higher rate of hardware-related complications requiring revision.

A novel proposed grading system for cerebellar arteriovenous malformations

OBJECTIVE

The objective of this study was to evaluate the existing Spetzler-Martin (SM), Spetzler-Ponce (SP), and Lawton-Young (LY) grading systems for cerebellar arteriovenous malformations (AVMs) and to propose a new grading system to estimate the risks associated with these lesions.

METHODS

Data for patients with cerebellar AVMs treated microsurgically in two tertiary medical centers were retrospectively reviewed. Data from patients at institution 1 were collected from September 1999 to February 2013, and at institution 2 from October 2008 to October 2015. Patient outcomes were classified as favorable (modified Rankin Scale [mRS] score 0-2) or poor (mRS score 3-6) at the time of discharge. Using chi-square and logistic regression analysis, variables associated with poor outcomes were assigned risk points to design the proposed grading system. The proposed system included neurological status prior to treatment (poor, +2 points), emergency surgery (+1 point), age > 60 years (+1 point), and deep venous drainage (deep, +1 point). Risk point totals of 0-1 comprised grade 1, 2-3 grade 2, and 4-5 grade 3.

RESULTS

A total of 125 cerebellar AVMs of 1328 brain AVMs were reviewed in 125 patients, 120 of which were treated microsurgically and included in the study. With our proposed grading system, we found poor outcomes differed significantly between each grade (p < 0.001), while with the SM, SP, and LY grading systems they did not (p = 0.22, p = 0.25, and p = 1, respectively). Logistic regression revealed grade 2 had 3.3 times the risk of experiencing a poor outcome (p = 0.008), while grade 3 had 9.9 times the risk (p < 0.001). The proposed grading system demonstrated a superior level of predictive accuracy (area under the receiver operating characteristic curve [AUROC] of 0.72) compared with the SM, SP, and LY grading systems (AUROC of 0.61, 0.57, and 0.51, respectively).

CONCLUSIONS

The authors propose a novel grading system for cerebellar AVMs based on emergency surgery, venous drainage, preoperative neurological status, and age that provides a superior prognostication power than the formerly proposed SM, SP, and LY grading systems. This grading system is clinically predictive of patient outcomes and can be used to better guide vascular neurosurgeons in clinical decision-making.

The Barrow Biomimetic Spine: effect of a 3-dimensional-printed spinal osteotomy model on performance of spinal osteotomies by medical students and interns

Background

The Schwab osteotomy grading scale-a unified osteotomy classification system created in 2014 by Schwab et al.-is one of many concepts in spine surgery that require detailed knowledge of 3-dimensional (3D) anatomy. 3D-printed spine models have demonstrated increasing utility in spine surgery as they more quickly communicate information on complex 3D anatomical relationships than planar imaging or 2-dimensional images. The purpose of this study was to evaluate the utility of a custom, 3D-printed spine model to help surgical trainees understand and perform the Schwab osteotomy grading scale.

Methods

Eight participants were randomized into 2 groups: group 1 received written instructional materials about the Schwab osteotomy grading scale, whereas group 2 received both written materials and a 3D-printed model of the spine with osteotomy regions demarcated. All participants were administered written and practical examinations.

Results

The group randomized to receive the 3D-printed model performed significantly better on both the written assessment (mean score, 7.75±0.50 vs. 5.75±0.50, P=0.023) and the practical examination (mean score, 1.75±0.32 vs. 1.08±0.09, P=0.025) than the group that received only written instructions.

Conclusions

Our results support the conclusion that this 3D-printed spine model is an effective adjunct to help early surgical trainees understand the Schwab osteotomy grading scale. Participants who received the model in addition to the source manuscript demonstrated improved theoretical knowledge and better performance on practical tests of complex spinal osteotomies. Similar models are likely to have utility in surgical training programs and as patient education models.

Variation in Coding Practices for Vestibular Schwannoma Surgery

Introduction  Nationwide databases are frequently used resources for assessing practice patterns and clinical outcomes. However, analyses based on billing codes may be limited by the inconsistent application of current procedural terminology (CPT) codes to specific operations. We investigated the variability among commonly used CPT codes for vestibular schwannomas resection and sought to identify factors that underlie this variation. Methods  The surgical procedure for 274 cases of vestibular schwannoma resections from two institutions was reviewed and classified as retrosigmoid, translabyrinthine, or middle fossa approaches. We then assessed the CPT codes assigned to each case and analyzed their association with surgical approach, surgeons involved, the coding specialty, and year of surgery. We further compared the incidence of CPT codes assigned for vestibular schwannoma surgeries in the American College Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2010 to 2014. Results  The majority (65%) of vestibular schwannoma resections within the institutional cohort were billed with skull base approach and/or excision codes, whereas 76% of cases in NSQIP were associated with a single craniotomy for tumor code. The use of skull base codes over the past decade increased within our institutional cohort but remained relatively stable within NSQIP. CPT codes did not consistently reflect the operative approaches for vestibular schwannomas. Conclusion  We observed significant variability in coding patterns for vestibular schwannoma surgeries within institutions, surgical practices, and national databases. These results call for discretion in interpretation of data from aggregated billing code-based nationwide databases and suggests a role for institutional standardization of CPT assignments for the same approaches.