bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retroperitoneal oblique corridor to the L2–S1 intervertebral discs in the lateral position: an anatomic study
Authors: Davis Timothy T. , Hynes Richard A. , Fung Daniel A. , Spann Scott W. , MacMillan Michael , Kwon Brian , Liu John , Acosta Frank , Drochner Thomas E. 
Published: November 2014

Object
Access to the intervertebral discs from L2–S1 in one surgical position can be challenging. The transpsoas minimally invasive surgical (MIS) approach is preferred by many surgeons, but this approach poses potential risk to neural structures of the lumbar plexus as they course through the psoas. The lumbar plexus and iliac crest often restrict the L4–5 disc access, and the L5–S1 level has not been a viable option from a direct lateral approach. The purpose of the present study was to investigate an MIS oblique corridor to the L2–S1 intervertebral disc space in cadaveric specimens while keeping the specimens in a lateral decubitus position with minimal disruption of the psoas and lumbar plexus.

Methods
Twenty fresh-frozen full-torso cadaveric specimens were dissected, and an oblique anatomical corridor to access the L2–S1 discs was examined. Measurements were taken in a static state and with mild retraction of the psoas. The access corridor was defined at L2–5 as the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5–S1 corridor of access was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel and vertically to the first vascular structure that crosses midline.

Results
The mean access corridor diameters in the static state and with mild psoas retraction, respectively, were as follows: at L2–3, 18.60 mm and 25.50 mm; at L3–4, 19.25 mm and 27.05 mm; and at L4–5, 15.00 mm and 24.45 mm. The L5–S1 corridor mean values were 14.75 mm transversely, from midline to the left common iliac vessel and 23.85 mm from the inferior endplate of L-5 cephalad to the first midline vessel.

Conclusions
The oblique corridor allows access to the L2–S1 discs while keeping the patient in a lateral decubitus position without a break in the table. Minimal psoas retraction without significant tendon disruption allowed for a generous corridor to the disc space. The L5–S1 disc space can be accessed from an oblique angle consistently with gentle retraction of the iliac vessels. This study supports the potential of an MIS oblique retroperitoneal approach to the L2–S1 discs.
National treatment trends, complications, and predictors of in-hospital charges for the surgical management of craniopharyngiomas in adults from 2007 to 2011
Authors: Zaidi Hasan A. , Chapple Kristina , Little Andrew S. 
Published: November 2014

Object
Treatment of craniopharyngiomas is one of the most demanding and controversial neurosurgical procedures performed. The authors sought to determine the factors associated with hospital charges and fees for craniopharyngioma treatment to identify possible opportunities for improving the health care economics of inpatient care.

Methods
The authors analyzed the hospital discharge database of the Nationwide Inpatient Sample (NIS) covering the period from 2007 through 2011 to examine national treatment trends for adults (that is, those older than 18 years) who had undergone surgery for craniopharyngioma. To predict the drivers of in-hospital charges, a multistep regression model was developed that accounted for patient demographics, acuity measures, comorbidities, hospital characteristics, and complications.

Results
The analysis included 606 patients who underwent resection of craniopharyngioma; 353 resections involved a transsphenoidal approach (58%) and 253 a transfrontal approach (42%). The mean age (± SD) of patients was 47.7 ± 16.3 years. The average hospital length of stay (LOS) was 7.6 ± 9 days. The mean hospital charge (± SD) was $92,300 ± $83,356. In total, 48% of the patients experienced postoperative diabetes insipidus or an electrolyte abnormality. A multivariate regression model demonstrated that LOS, hospital volume for the selected procedure, the surgical approach, postoperative complications, comorbidities, and year of surgery were all significant predictors of in-hospital charges. The statistical model accounted for 54% of the variance in in-hospital charge.

Conclusions
This analysis of inpatient hospital charges in patients undergoing craniopharyngioma surgery identified key drivers of charges in the perioperative period. Prospective studies designed to evaluate the long-term resource utilization in this complex patient population would be a useful future direction.
Neurosurgeons' responses to changing Medicare reimbursement
Authors: Rosenow Joshua M. , Orrico Katie O. 
Published: November 2014

Object
Medicare reimbursement for physician services has been declining even as the number of Medicare enrollees has been increasing. The number of Medicare participants will only continue to grow as the American population ages and the Patient Protection and Affordable Care Act goes into effect. Efforts to increase reimbursement for physician services through Medicare are often met with data showing that most neurosurgeons continue to participate in the program despite these cutbacks. To better understand this dichotomy, practicing neurosurgeons were surveyed to gauge their response to cutbacks in the Medicare program beyond just their participation status.

Methods
An Internet-based survey invitation was emailed to 3469 practicing neurosurgeons. Reminder emails were sent at intervals over several weeks to help increase the response rate.

Results
Among respondents, an overwhelming percentage (96.8%) participated in Medicare. The neurosurgeons indicated that about one-third of their patient population was covered by Medicare. They also reported limiting the number of Medicare patients they see through a variety of mechanisms: only seeing Medicare patients with a specific diagnosis or from certain referring physicians or limiting the number of appointment slots for Medicare patients. Many respondents stated that further declines in Medicare reimbursement would lead to a reduction in their participation.

Conclusions
While most responding neurosurgeons do participate in the Medicare program, a substantial proportion modulates their participation through a variety of mechanisms. These barriers to care access for Medicare patients are only expected to become greater if further declines in reimbursement are implemented through the program.
Surgery is cost-effective treatment for young patients with vestibular schwannomas: decision tree modeling of surgery, radiation, and observation
Authors: Zygourakis Corinna C. , Oh Taemin , Sun Matthew Z. , Barani Igor , Kahn James G. , Parsa Andrew T. 
Published: November 2014

Object
Vestibular schwannomas (VSs) are managed in 3 ways: observation (“wait and scan”); Gamma Knife surgery (GKS); or microsurgery. Whereas there is considerable literature regarding which management approach is superior, there are only a few studies addressing the cost of treating VSs, and there are no cost-utility analyses in the US to date.

Methods
In this study, the authors used the University of California at San Francisco medical record and hospital accounting databases to determine total hospital charges and costs for 33 patients who underwent open surgery, 42 patients who had GKS, and 12 patients who were observed between 2010 and 2013. The authors then performed decision-tree analysis to determine which treatment paradigm produces the highest quality-adjusted life years and to calculate the incremental cost-effectiveness ratio, depending on the patient's age at VS diagnosis.

Results
The average total hospital cost over a 3-year period for surgically treated patients was $80,074 (± $49,678) versus $9737 (± $5522) for patients receiving radiosurgery and $1746 (± $2792) for patients who were observed. When modeling the most debilitating symptoms and worst outcomes of VSs (vertigo and death) at different ages at diagnosis, radiation is dominant to observation at all ages up to 70 years. Surgery is cost-effective when compared with radiation (incremental cost-effectiveness ratio < $150,000) at younger ages at diagnosis (< 45 years old).

Conclusions
In this model, surgery is a cost-effective alternative to radiation when VS is diagnosed in patients at < 45 years. For patients ≥ 45 years, radiation is the most cost-effective treatment option.
Assessing the cost of contemporary pituitary care
Authors: McLaughlin Nancy , Martin Neil A. , Upadhyaya Pooja , Bari Ausaf A. , Buxey Farzad , Wang Marilene B. , Heaney Anthony P. , Bergsneider Marvin 
Published: November 2014

Object
Knowledge of the costs incurred through the delivery of neurosurgical care has been lagging, making it challenging to design impactful cost-containment initiatives. In this report, the authors describe a detailed cost analysis for pituitary surgery episodes of care and demonstrate the importance of such analyses in helping to identify high-impact cost activities and drive value-based care.

Methods
This was a retrospective study of consecutively treated patients undergoing an endoscopic endonasal procedure for the resection of a pituitary adenoma after implementation and maturation of quality-improvement initiatives and the implementation of cost-containment initiatives.

Results
The cost data pertaining to 27 patients were reviewed. The 2 most expensive cost activities during the index hospitalization were the total operating room (OR) and total bed-assignment costs. Together, these activities represented more than 60% of the cost of hospitalization. Although value-improvement initiatives contributed to the reduction of variation in the total cost of hospitalization, specific cost activities remained relatively variable, namely the following: 1) OR charged supplies, 2) postoperative imaging, and 3) use of intraoperative neuromonitoring. These activities, however, each contributed to less than 10% of the cost of hospitalization. Bed assignment was the fourth most variable cost activity. Cost related to readmission/reoperation represented less than 5% of the total cost of the surgical episode of care.

Conclusions
After completing a detailed assessment of costs incurred throughout the management of patients undergoing pituitary surgery, high-yield opportunities for cost containment should be identified among the most expensive activities and/or those with the highest variation. Strategies for safely reducing the use of the targeted resources, and related costs incurred, should be developed by the multidisciplinary team providing care for this patient population.
A socioeconomic analysis of intraoperative neurophysiological monitoring during spine surgery: national use, regional variation, and patient outcomes
Authors: James Whitney Sheen , Rughani Anand I. , Dumont Travis M. 
Published: November 2014

Object
In the United States in recent years, a dramatic increase in the use of intraoperative neurophysiological monitoring (IONM) during spine surgeries has been suspected. Myriad reasons have been proposed, but no clear evidence confirming this trend has been available. In this study, the authors investigated the use of IONM during spine surgery, identified patterns of geographic variation, and analyzed the value of IONM for spine surgery cases.

Methods
In this retrospective analysis, the Nationwide Inpatient Sample was queried for all spine surgeries performed during 2007–2011. Use of IONM (International Classification of Diseases, Ninth Revision, code 00.94) was compared over time and between geographic regions, and its effect on patient independence at discharge and iatrogenic nerve injury was assessed.

Results
A total of 443,194 spine procedures were identified, of which 85% were elective and 15% were not elective. Use of IONM was recorded for 31,680 cases and increased each calendar year from 1% of all cases in 2007 to 12% of all cases in 2011. Regional use of IONM ranged widely, from 8% of cases in the Northeast to 21% of cases in the West in 2011. Iatrogenic nerve and spinal cord injury were rare; they occurred in less than 1% of patients and did not significantly decrease when IONM was used.

Conclusions
As costs of spine surgeries continue to rise, it becomes necessary to examine and justify use of different medical technologies, including IONM, during spine surgery.
Cerebrospinal fluid shunt placement in the pediatric population: a model of hospitalization cost
Authors: Lam Sandi K. , Srinivasan Visish M. , Luerssen Thomas G. , Pan I-Wen 
Published: November 2014

Object
There have been no large-scale analyses on cost drivers in CSF shunt surgery for the treatment of pediatric hydrocephalus. The objective of this study was to develop a cost model for hospitalization costs in pediatric CSF shunt surgery and to examine risk factors for increased costs.

Methods
Data were extracted from the Kids' Inpatient Database (KID) of the Healthcare Cost and Utilization Project. Children with initial CSF shunt placement in the 2009 KID were examined. Patient charge was converted to cost using a cost-to-charge ratio. The factors associated with costs of CSF shunt hospitalizations were examined, including patient demographics, hospital characteristics, and clinical data. The natural log transformation of cost per inpatient day (CoPID) was analyzed. Three multivariate linear regression models were used to characterize the cost. Variance inflation factor was used to identify multicollinearity for each model.

Results
A total of 2519 patients met the inclusion criteria and were included in study. Average cost and length of stay (LOS) for initial shunt placement were $49,317 ± $74,483 (US) and 18.2 ± 28.5 days, respectively. Cost per inpatient day was $4249 ± $2837 (median $3397, range $80–$22,263). The average number of registered nurse (RN) full-time equivalents (FTEs) per 1000 adjusted inpatient days was 5.8 (range 1.6–10.8). The final model had the highest adjusted coefficient of determination (R2 = 0.32) and was determined to be the best among 3 models. The final model showed that child age, hydrocephalus etiology, weekend admission, number of chronic diseases, hospital type, number of RN FTEs per 1000 adjusted inpatient days, number of procedures, race, insurance type, income level, and hospital regions were associated with CoPID.

Conclusions
A patient's socioeconomic status, such as race, income level, and insurance, in addition to hospitalrelated factors such as number of hospital RN FTEs, hospital type, and US region, could affect the costs of initial CSF shunt placement, in addition to clinical factors such as hydrocephalus origin and LOS. To create a cost model of initial CSF shunt placement in the pediatric population, consideration of such nonclinical factors may be warranted.
Population viability of Pediocactus bradyi (Cactaceae) in a changing climate
Authors: Shryock Daniel F. , Esque Todd C. , Lee Hughes  
Published: November 2014

• Premise of the study: A key question concerns the vulnerability of desert species adapted to harsh, variable climates to future climate change. Evaluating this requires coupling long‐term demographic models with information on past and projected future climates. We investigated climatic drivers of population growth using a 22‐yr demographic model for Pediocactus bradyi, an endangered cactus in northern Arizona.• Methods: We used a matrix model to calculate stochastic population growth rates (λs) and the relative influences of life‐cycle transitions on population growth. Regression models linked population growth with climatic variability, while stochastic simulations were used to (1) understand how predicted increases in drought frequency and extreme precipitation would affect λs, and (2) quantify variability in λs based on temporal replication of data.• Key results: Overall λs was below unity (0.961). Population growth was equally influenced by fecundity and survival and significantly correlated with increased annual precipitation and higher winter temperatures. Stochastic simulations increasing the probability of drought and extreme precipitation reduced λs, but less than simulations increasing the probability of drought alone. Simulations varying the temporal replication of data suggested 14 yr were required for accurate λs estimates.• Conclusions: Pediocactus bradyi may be vulnerable to increases in the frequency and intensity of extreme climatic events, particularly drought. Biotic interactions resulting in low survival during drought years outweighed increased seedling establishment following heavy precipitation. Climatic extremes beyond historical ranges of variability may threaten rare desert species with low population growth rates and therefore high susceptibility to stochastic events.
Annular floral nectary with oil‐producing trichomes in Salvia farinacea (Lamiaceae): Anatomy, histochemistry, ultrastructure, and significance
Authors: Zhang Xiaohui , Sawhney Vipen K. , Davis Arthur R. 
Published: November 2014

• Premise of the study: Many angiosperms produce nectar that entices pollinator visits. Each floral nectary tends to embody a singular form, such as the receptacular ring arising beneath the ovary in mint flowers (Lamiaceae). Exceptionally, the annular floral nectary in Salvia farinacea possesses modified stomata plus secretory trichomes. This first study of nectary ultrastructure within the largest genus of Lamiaceae examined this unusual condition.• Methods: Nectary anatomy, histochemistry, and ultrastructure were investigated from fresh and fixed material using light microscopy and scanning electron and transmission electron microscopy.• Key results: The annular nectary encircled the ovary plus extended ventrally as a projection. Modified stomata occurred only in the projection's abaxial epidermis. Conversely, peltate trichomes with a basal cell, a stalk cell, and 4‐7 head cells were interspersed among the ovary lobes and covered the projection's adaxial surface. Phloem and xylem supplied the nectary interior, where parenchyma cells had numerous mitochondria and plastids with little starch, but few dictyosomes and little endoplasmic reticulum. Nectar accumulated as a drop opposite the projection's abaxial surface, escaping through stomatal pores and probably the cuticle. However, the annular nectary's glistening trichomes secreted a Sudan‐positive product largely retained below the distended cuticle, but not nectar.• Conclusions: This first ultrastructural study of co‐occurring secretory trichomes and modified stomata on a mint nectary suggests multiple interactive functions for this atypical structure. These trichomes—possibly generating a substance informative to pollinators or as an ovarian defense against phytophagy—produced oil in an aqueous milieu, rather than contributing fluid to nectar.
Understanding Limitations in At-work Productivity in Patients with Active Ankylosing Spondylitis: The Role of Work-related Contextual Factors
Authors: Boonen Annelies , Boone Caroline , Albert Adelin , Mielants Herman 
Published: November 2014

Objective.To explore the effect of health-related and contextual factors on presenteeism, absenteeism, and overall work productivity loss in patients with active ankylosing spondylitis (AS).Methods.Consecutive patients with AS starting their first tumor necrosis factor inhibitor and in paid employment were eligible. Patients completed the Work Productivity and Activity Impairment (WPAI) questionnaire for AS to assess presenteeism, absenteeism, and overall work productivity loss in the previous 7 days. In addition, they answered questions about work characteristics (type, characteristics of workplace, satisfaction of contacts with colleagues, and importance of work in life) and health status [Bath AS Functional Index (BASFI), AS Disease Activity Score-C-reactive protein (ASDAS-CRP)]. Physicians assessed the Bath Ankylosing Spondylitis Metrology Index, presence of articular and extraarticular manifestations, comorbidities, and laboratory indicators of inflammation. Stepwise regression models were computed to determine which work-related and health-related factors contributed to WPAI outcomes.Results.The study included 80 patients. The WPAI presenteeism, absenteeism, and overall work productivity loss scores were 49.1%, 30.2%, and 53.1%, respectively. Presenteeism was associated with higher BASFI, female sex, and poor quality of contact with colleagues. Absenteeism was associated with increasing age, current smoking status, higher ASDAS-CRP, and low importance of work for life. Overall work productivity loss was associated with female sex, higher BASFI, past adaptation of job because of illness, number of working hours, and manual profession.Conclusion.Both health-related and contextual factors contribute to work limitations in patients with AS and suggest additional opportunities for improvement by addressing the working environment.
Etiopathogenic Role of Surfactant Protein D in the Clinical and Immunological Expression of Primary Sjögren Syndrome
Authors: Soto-Cárdenas María José , Gandía Myriam , Brito-Zerón Pilar , Arias Maria Teresa , Armiger Noelia , Bové Albert , Bosch Xavier , Retamozo Soledad , Akasbi Miriam , Pérez-De-Lis Marta , Gueitasi Hoda , Kostov Belchin , Pérez-Alvarez Roberto , Siso-Almirall Antoni , Lozano Francisco , Ramos-Casals Manuel 
Published: November 2014

Objective.To analyze the etiopathogenic role of genetic polymorphisms and serum levels of surfactant protein-D (SP-D) in primary Sjögren syndrome (pSS).Methods.We analyzed 210 consecutive patients with pSS.SFTPDgenotyping (M11T polymorphism rs721917) was analyzed by sequence-based typing and serum SP-D by ELISA.Results.Thirty-two patients (15%) had the Thr11/Thr11 genotype, 80 (38%) the Met11/Met11 genotype, and 96 (46%) the Met11/Thr11 genotype; 2 patients could not be genotyped. Patients carrying the Thr11/Thr11 genotype had a higher prevalence of renal involvement (13% vs 1% and 4% in comparison with patients carrying the other genotypes, p = 0.014). Serum SP-D levels were analyzed in 119 patients (mean 733.94 ± 49.88 ng/ml). No significant association was found between serum SP-D levels and the SP-D genotypes. Higher mean values of serum SP-D were observed in patients with severe scintigraphic involvement (851.10 ± 685.69 vs 636.07 ± 315.93 ng/ml, p = 0.038), interstitial pulmonary disease (1053.60 ± 852.03 vs 700.36 ± 479.33 ng/ml, p = 0.029), renal involvement (1880.64 ± 1842.79 vs 716.42 ± 488.01 ng/ml, p = 0.002), leukopenia (899.83 ± 661.71 vs 673.13 ± 465.88 ng/ml, p = 0.038), positive anti-Ro/SS-A (927.26 ± 731.29 vs 642.75 ± 377.23 ng/ml, p = 0.006), and positive anti-La/SS-B (933.28 ± 689.63 vs 650.41 ± 428.14 ng/ml, p = 0.007), while lower mean values of serum SP-D were observed in patients with bronchiectasis (489.49 vs 788.81 ng/ml, p = 0.019).Conclusion.In pSS, high SP-D levels were found in patients with severe glandular involvement, hypergammaglobulinemia, leukopenia, extraglandular manifestations, and positive anti-Ro/La antibodies. The specific association between SP-D levels and pulmonary and renal involvements may have pathophysiological implications.