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Dive into the research topics where Dennis Vasquez-Montes is active.

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Featured researches published by Dennis Vasquez-Montes.


World Neurosurgery | 2017

Traumatic Fractures of the Cervical Spine: Analysis of Changes in Incidence, Etiology, Concurrent Injuries and Complications Among 488,262 Patients from 2005-2013

Peter G. Passias; Gregory W. Poorman; Frank A. Segreto; Cyrus M. Jalai; Samantha R. Horn; Cole A. Bortz; Dennis Vasquez-Montes; Shaleen Vira; Olivia J. Bono; Rafael De la Garza-Ramos; John Y. Moon; Charles Wang; Brandon P. Hirsch; Peter L. Zhou; Michael C. Gerling; Heiko Koller; Virginie Lafage

OBJECTIVEnThe causes and epidemiology of traumatic cervical spine fracture have not been described with sufficient power or recency. Our goal is to describe demographics, incidence, cause, spinal cord injuries (SCIs), concurrent injuries, treatments, and complications of traumatic cervical spine fractures.nnnMETHODSnA retrospective review was carried out of the Nationwide Inpatient Sample. International Classification of Disease, Ninth Revision E-codes identified trauma cases from 2005 to 2013. Patients with cervical fracture were isolated. Demographics, incidence, cause, fracture levels, concurrent injuries, surgical procedures, and complications were analyzed. t tests elucidated significance for continuous variables and χ2 for categorical variables. Level of significance was P < 0.05.nnnRESULTSnA total of 488,262 patients were isolated (age, 55.96 years; male, 60.0%; white, 77.5%). Incidence (2005, 4.1% vs. 2013, 5.4%), Charlson Comorbidity Index (2005, 0.6150 vs. 2013, 1.1178), and total charges (2005,


World Neurosurgery | 2018

The Influence of Body Mass Index on Achieving Age-Adjusted Alignment Goals in Adult Spinal Deformity Corrective Surgery with Full-Body Analysis at 1 Year

Samantha R. Horn; Frank A. Segreto; Subbu Ramchandran; Gregory R. Poorman; Akhila Sure; Bryan Marascalachi; Cole A. Bortz; Christopher Varlotta; Jared C. Tishelman; Dennis Vasquez-Montes; Yael Ihejirika; Peter L. Zhou; John Y. Moon; Renaud Lafage; Shaleen Vira; Cyrus M. Jalai; Charles Wang; Kartik Shenoy; Thomas J. Errico; Virginie Lafage; Aaron J. Buckland; Peter G. Passias

71,228.60 vs. 2013,


World Neurosurgery | 2018

Full-Body Analysis of Adult Spinal Deformity Patients' Age-Adjusted Alignment at 1 Year

Peter G. Passias; Samantha R. Horn; Nicholas J. Frangella; Gregory W. Poorman; Dennis Vasquez-Montes; Cole A. Bortz; Frank A. Segreto; John Y. Moon; Peter L. Zhou; Shaleen Vira; Akhila Sure; Bryan M. Beaubrun; Jared C. Tishelman; Subaraman Ramchandran; Cyrus M. Jalai; Wesley H. Bronson; Charles Wang; Virginie Lafage; Aaron J. Buckland; Thomas J. Errico

108,119.29) have increased since 2005, whereas length of stay decreased (2005, 9.22 vs. 2013, 7.86) (all Pxa0<xa00.05). The most common causes were motor vehicle accident (29.3%), falls (23.7%), and pedestrian accidents (15.7%). The most frequent fracture types were closed at C2 (32.0%) and C7 (20.9%). Concurrent injury rates have significantly increased since 2005 (2005, 62.3% vs. 2013, 67.6%). Common concurrent injuries included fractures to the rib/sternum/larynx/trachea (19.6%). Overall fusion rates have increased since 2005 (2005, 15.7% vs. 2013, 18.0%), whereas decompressions and halo insertion rates have decreased (all P < 0.05). SCIs have significantly decreased since 2005, except for upper cervical central cord syndrome. Complication rates have significantly increased since 2005 (2005, 31.6% vs. 2013, 36.2%). Common complications included anemia (7.7%), mortality (6.6%), and acute respiratory distress syndrome (6.6%).nnnCONCLUSIONSnIncidence, complications, concurrent injuries, and fusions have increased since 2005. Length of stay, SCIs, decompressions, and halo insertions have decreased. Indicated trends should guide future research in management guidelines.


The Journal of Spine Surgery | 2018

Differences in primary and revision deformity surgeries: following 1,063 primary thoracolumbar adult spinal deformity fusions over time

Gregory W. Poorman; Peter L. Zhou; Dennis Vasquez-Montes; Samantha R. Horn; Cole A. Bortz; Frank A. Segreto; Joshua D. Auerbach; John Y. Moon; Jared C. Tishelman; Michael C. Gerling; Rafael De la Garza-Ramos; Justin C. Paul; Peter G. Passias

BACKGROUNDnThe impact of obesity on global spinopelvic alignment is poorly understood. This study investigated the effect of body mass index on achieving alignment targets and compensation mechanisms after corrective surgery for adult spinal deformity (ASD).nnnMETHODSnRetrospective review of a single-center database. Inclusion: patients ≥18 years with full-body stereographic images (baseline and 1 year) and who met ASD criteria (sagittal vertical axis [SVA] >5 cm, pelvic incidence minus lumbar lordosis [PI-LL] >10°, coronal curvature >20° or pelvic tilt >20°). Patients were stratified by age (<40, 40-65, and ≥65 years) and body mass index (<25, 25-30, and >30). Postoperative alignment was compared with age-adjusted ideal values. Prevalence of patients who matched ideals and unmatched (undercorrected/overcorrected) was assessed. Health-related quality of life (HRQL) scores, alignment, and compensatory mechanisms were compared across cohorts using analysis of variance and temporally with paired t tests.nnnRESULTSnA total of 116 patients were included (average age, 62 years; 66% female). After corrective surgery, obese and overweight patients had more residual malalignment (worse PI-LL, T1 pelvic angle, pelvic tilt, and SVA) compared with normal patients (P < 0.05). In addition, obese and overweight patients recruited more pelvic shift (obese, 62.36; overweight, 49.80; normal, 31.50) and had a higher global sagittal angle (obese, 6.51; overweight, 6.35; normal, 3.40) (P < 0.05). Obese and overweight patients showed lower overcorrection rates and higher undercorrection rates (P < 0.05). Obese patients showed worse postoperative HRQL scores (Scoliosis Research Society 22 Questionnaire, Oswestry Disability Index, visual analog scale-leg) than did overweight and normal patients (P < 0.05). Obese and overweight patients who matched age-adjusted alignment targets for SVA or PI-LL showed no HRQL improvements (P > 0.05).nnnCONCLUSIONSnAfter surgery, obese patients were undercorrected, showed more residual malalignment, recruited more pelvic shift, and had a greater global sagittal angle and worse HRQL scores. The benefits from age-adjusted alignment targets seem to be less substantial for obese and overweight patients.


The Journal of Spine Surgery | 2018

Developments in the treatment of Chiari type 1 malformations over the past decade

Peter G. Passias; Alexandra Pyne; Samantha R. Horn; Gregory W. Poorman; Muhammad Burhan Ud Din Janjua; Dennis Vasquez-Montes; Cole A. Bortz; Frank A. Segreto; Nicholas J. Frangella; Matthew Y. Siow; Akhila Sure; Peter L. Zhou; John Y. Moon; Shaleen Vira

BACKGROUNDnPrevious studies have built a foundation for understanding compensation in patients with adult spinal deformity (ASD) by using full-body stereographic assessments. These mechanisms, in relation to age-adjusted alignment targets, have yet to be studied fully. The aim of this study was to assess lower-limb compensatory mechanisms of patients failing to meet age-adjusted alignment goals.nnnMETHODSnPatients with ASD ≥40 years with full body baseline and follow-up radiographs were included. Patients were stratified by age (40-65 years, >65 years) and spinopelvic correction. Lower-limb compensation parameters (pelvic shift, hip extension, knee flexion [KA], ankle flexion [AA], and global sagittal angle [GSA]) for patients who matched and failed to match age-adjusted alignment targets were compared with analysis of variance and t-test analysis.nnnRESULTSnIn total, 108 patients were included. At 1 year, AA increased with age in the match pelvic tilt (PT) andxa0spinopelvic mismatch (PI-LL) cohorts (PT: AA, 5.6-7.8, Pxa0= 0.041; PI-LL: 4.9-8.8, Pxa0= 0.026). KA, AA, and GSA increased with age in the match sagittal vertical axis (SVA) cohort (KA: 3.8-13.1, Pxa0= 0.002; AA: 5.8-10.2, Pxa0=xa00.008; GSA: 3.9-7.8, P < 0.001), as did KA and GSA in the match T1 pelvic angle group (KA: 1.8-8.7, Pxa0= 0.020; GSA: 2.6-5.7, Pxa0= 0.004).nnnCONCLUSIONSnGreater compensation captured by KA and GSA was associated with age progression in the match SVA and T1 pelvic angle cohorts. In addition, older SVA, PT, and PI-LL match cohorts used increased AA, suggesting that ideal postoperative alignment of aged individuals with ASD involves increased compensation.


Journal of orthopaedics | 2018

Incidence, trends, and associated risks of developmental hip dysplasia in patients with Early Onset and Adolescent Idiopathic Scoliosis

Frank A. Segreto; Dennis Vasquez-Montes; Avery E. Brown; Cole A. Bortz; Samantha R. Horn; Peter L. Zhou; Shaleen Vira; Joseph F. Baker; Anthony Petrizzo; Renaud Lafage; Virginie Lafage; Thomas J. Errico; Peter G. Passias

BackgroundnThis study aims to describe properties of adult spinal deformity (ASD) revisions relative to primary surgeries and determine clinical variables that can predict revision. ASD is a common pathology that can lead to decreased quality of life, pain, physical limitations, and dissatisfaction with self-image. Durability of interventions for deformity treatment is of paramount concern to surgeons, as revision rates remain high.nnnMethodsnPatients undergoing thoracolumbar fusion, five or more levels, for scoliosis (primary diagnosis ICD-9 737.x) were identified on a state-wide database. Primary and revision (returning for re-fusion procedure) surgeries were compared based on demographic, hospital stay, and clinical characteristics. Differences between primary and revision surgeries, and predictors of primary surgeries requiring revision, utilized binary logistic regression controlling for age, comorbidity burden, and levels fused.nnnResultsnA total of 1,063 patients (average 7.4 levels fused, mean age: 47.6 years, 69.0% female) undergoing operative treatment for ASD were identified, of which 123 (average 7.1 levels fused, 11.6%, mean age 61.43, 80.5% female) had surgical revision. Primary surgeries were ~0.3 levels longer (P=0.013), used interbody ~11% more frequently (P=0.020), and used BMP ~12% less frequently (P=0.008). Revisions occurred 176.4 days after the primary on average. The most frequent causes of revisions were: 43.09% implant failure, 24.39% acquired kyphosis, and 14.63% enduring scoliosis. After controlling for age, comorbidities, and levels fused older, more comorbid, female, and white-race patients were more likely to be revised. Upon multivariate regression, after controlling for age and levels fused, overall complications remained non-different (OR: 0.8, 95% CI: 0.6-1.2). However, revision remained an independent predictor for infection (OR: 5.5, 95% CI: 2.8-10.5).nnnConclusionsnIn a statewide database with individual patient follow up of up to 4 years 10% of ASD patients undergoing scoliosis correction required revision. Revision surgeries had higher infection incidence.


Journal of Neurosurgery | 2018

The value of sitting radiographs: analysis of spine flexibility and its utility in preoperative planning for adult spinal deformity surgery

M. Burhan Janjua; Jared C. Tishelman; Dennis Vasquez-Montes; Max Vaynrub; Thomas J. Errico; Aaron J. Buckland; Themistocles S. Protopsaltis

BackgroundnChiari malformations type 1 (CM-1), a developmental anomaly of the posterior fossa, usually presents in adolescence or early adulthood. There are few studies on the national incidence of CM-1, taking into account outcomes based on concurrent diagnoses. To quantify trends in treatment and associated diagnoses, as retrospective review of the Kids Inpatient Database (KID) from 2003-2012 was conducted.nnnMethodsnPatients aged 0-20 with primary diagnosis of CM-1 in the KID database were identified. Demographics and concurrent diagnoses were analyzed using chi-squared and t-tests for categorical and numerical variables, respectively. Trends in diagnosis, treatments, and outcomes were analyzed using analysis of variance (ANOVA).nnnResultsnFive thousand four hundred and thirty-eight patients were identified in the KID database with a primary diagnosis of CM-1 (10.5 years, 55% female). CM-1 primary diagnoses have increased over time (45 to 96 per 100,000). CM-1 patients had the following concurrent diagnoses: 23.8% syringomyelia/syringobulbia, 11.5% scoliosis, 5.9% hydrocephalus, 2.2% tethered cord syndrome. Eighty-three point four percent of CM-1 patients underwent surgical treatment, and rate of surgical treatment for CM-1 increased from 2003-2012 (66% to 72%, P<0.001) though complication rate decreased (7% to 3%, P<0.001) and mortality rates remained constant. Seventy percent of surgeries involved decompression-only, which increased neurologic complications compared to fusions (P=0.039). Cranial decompressions decreased from 2003-2012 (42.2-30.5%) while spinal decompressions increased (73.1-77.4%). Fusion rates have increased over time (0.45% to 1.8%) and are associated with higher complications than decompression-only (11.9% vs. 4.7%). Seven point four percent of patients experienced at least one peri-operative complication (nervous system, dysphagia, respiratory most common). Patients with concurrent hydrocephalus had increased; nervous system, respiratory and urinary complications (P<0.006) and syringomyelia increased the rate of respiratory complications (P=0.037).nnnConclusionsnCM-1 diagnoses have increased in the last decade. Despite the decrease in overall complication rates, fusions are becoming more common and are associated with higher peri-operative complication rates. Commonly associated diagnoses including syringomyelia and hydrocephalus, can dramatically increase complication rates.


Journal of Clinical Neuroscience | 2018

Chiari malformation clusters describe differing presence of concurrent anomalies based on Chiari type

Samantha R. Horn; Nicholas Shepard; Dennis Vasquez-Montes; Cole A. Bortz; Frank A. Segreto; Rafael De la Garza Ramos; C. Rory Goodwin; Peter G. Passias

IntroductionnEarly Onset and Adolescent Idiopathic Scoliosis, relatively common diagnoses (∼3% general population), have been associated with developmental dysplasia of the hip (DDH); a more rare spectrum of anomalies related to the abnormal development of acetabulum, proximal femur, and hip joint. To the best of our knowledge, no high powered investigations have been performed in an attempt to assess incidence and associated risks of DDH in scoliosis patients.nnnMethodsnThe KID database was queried for ICD-9 codes from 2003 to 2012 pertaining to EOS (Congenital and Idiopathic <10y/o) and AIS patients. Descriptive analysis assessed patient demographics and yearly trends in hip dysplasia rates. EOS and AIS patients with hip dysplasia were isolated, and incidence of hospital admissions for associated anomalies (osteonecrosis, osteoarthritis, recurrent hip dislocation, hip ankylosis) and hip arthroplasty (totalxa0+xa0partial) were investigated. Univariate analysis of hip pathology determined significant predictors of hip arthroplasty. Binary logistic regression analysis was used to determine the relationship between these predictors.nnnResultsn111,827 scoliosis patients (EOS: 25,747; AIS: 77,183) were included. AIS patients were older (15.2 vs 4.3), more female (64.2% vs 52.1%), had a higher CCI (0.84 vs 0.64), and less racially diverse (all pu202f<u202f0.001). The incidence of hip dysplasia was 1.4% for AIS patients and 3.9% for EOS patients (pu202f<u202f0.001). Of the AIS (nu202f=u202f1073) and EOS (nu202f=u202f1005) patients with hip dysplasia, 0.3% (pu202f>u202f0.05 between groups) developed hip osteonecrosis, 0% of patients were coded as having a hip labral tear, hip ankylosis, and 0.6% (EOS: 0.2%; AIS: 0.9%, pu202f=u202f0.025) developed hip osteoarthritis. AIS patients were more likely to have recurrent hip dislocations (35.4% vs 17.0%, pu202f<u202f0.001), and both groups had similar primary hip arthroplasty rates (6.7% vs 5.4%, pu202f=u202f0.118) and revision hip arthroplasty rates (0% vs 0.4%, pu202f=u202f0.053). Hip osteoarthritis (OR: 13.43[5.21-34.66], p=<0.001) and older age (OR: 1.039[1.007-1.073], pu202f=u202f0.017) were the only significant predictors of hip arthroplasty (p=<.001).nnnConclusionsnThe incidence of hip dysplasia in EOS and AIS populations is higher than that of the general population. The rate of DDH was 3.9% and 1.8% for EOS and AIS, respectively. While the incidence of DDH is higher, associated anomalies of osteoarthritis, osteonecrosis, labral tears, and ankylosis appear to be a minimal risk for AIS and EOS patients with Hip Dysplasia.


Acta Neurochirurgica | 2018

Cluster analysis describes constellations of cardiac anomalies presenting in spinal anomaly patients

Peter G. Passias; Gregory W. Poorman; Dennis Vasquez-Montes; Charles Wang; Cyrus M. Jalai; Samantha R. Horn; Leah Steinmetz; Cole A. Bortz; Frank A. Segreto; John Y. Moon; Peter L. Zhou; Shaleen Vira

Sitting radiographs are a valuable tool to consider the thoracic compensatory mechanism in patients who are candidates for thoracolumbar correction surgery.


The Spine Journal | 2017

Predictive model for distal junctional kyphosis after cervical deformity surgery

Peter G. Passias; Dennis Vasquez-Montes; Gregory W. Poorman; Themistocles S. Protopsaltis; Samantha R. Horn; Cole A. Bortz; Frank A. Segreto; Christopher P. Ames; Justin S. Smith; Virginie Lafage; Renaud Lafage; Eric O. Klineberg; Shaffrey Ci; Shay Bess; Frank J. Schwab

Chiari malformations are structural defects in the posterior fossa where the cerebellum displaces caudally into the foramen magnum and upper spinal canal. These malformations are classified by severity as Types 1-4, each presenting with different associated and/or concurrent conditions and anomalies. The aim of this study was to utilize a nationwide database to study patients with Chiari malformations including their concurrent diagnoses and associated anomalies. Using a retrospective review of the Nationwide Inpatient Sample (NIS) database from 2003 to 2012, Chiari malformations were assessed by Chiari type and rates of concurrence for various additional anomalies were evaluated using cross-tabulations. There were 305,726 national cases of Chiari Type 1, 119,632 cases of Chiari Type 2, 15,540 cases of Type 3, and 79,663 cases of Type 4. Overall 44.3% of Chiari patients have at least one concurrent anomaly. Stratified by Chiari Type, 7.1% of Type 1 patients, 12.3% of Type 2, and 100% of Type 3 and 4 have at least one concurrent anomaly. The most common isolated neurologic associations were tethered cord, syringomyelia, and hydrocephalus, while the most common anomaly clusters were syringomyelia and scoliosis in Type 1 (0.63), tethered cord syndrome and scoliosis (0.72%) in Type 2, encephalocele and acquired hydrocephalus (11.45%) in Type 3, and reduction deformity of the brain with acquired hydrocephalus (15.95%) in Type 4. Chiari malformations have strong associations with other abnormalities outside of known relationships in the current classification. While neurologic abnormalities are most common, additional body systems are frequently involved especially with worsening hindbrain defects.

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Virginie Lafage

Hospital for Special Surgery

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Peter L. Zhou

SUNY Downstate Medical Center

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Renaud Lafage

Hospital for Special Surgery

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