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Dive into the research topics where Mark P. Piedra is active.

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Featured researches published by Mark P. Piedra.


Journal of Neurosurgery | 2013

Timing of cranioplasty after decompressive craniectomy for ischemic or hemorrhagic stroke.

Mark P. Piedra; Brian T. Ragel; Aclan Dogan; Nicholas D. Coppa; Johnny B. Delashaw

OBJECT The optimal timing of cranioplasty after decompressive craniectomy for stroke is not known. Case series suggest that early cranioplasty is associated with higher rates of infection while delaying cranioplasty may be associated with higher rates of bone resorption. The authors examined whether the timing of cranioplasty after decompressive craniectomy for stroke affects postoperative complication rates. METHODS A retrospective cohort study was undertaken to evaluate complication rates in patients undergoing cranioplasty at early (within 10 weeks of craniectomy) or late (≥ 10 weeks) stages. Multivariate logistic regression analysis was used to determine characteristics that would predict complications in patients undergoing cranioplasty after decompressive craniectomy for stroke. RESULTS While the overall complication rate was higher in the early cranioplasty cohort (22% vs 16% in the late cranioplasty cohort), the difference was not statistically significant (p = 0.5541). Patients in the early cranioplasty cohort had lower rates of postoperative hematoma but higher rates of infection. Presence of a CSF shunt was the only significant predictor of complications (OR 8.96, 95% CI 1.84-43.6). CONCLUSIONS Complications rates for early cranioplasty (within 10 weeks of craniectomy) are similar to those encountered when cranioplasty is delayed, although the cohort size in this study was too small to state equivalence. Patients with a ventriculoperitoneal shunt are at higher risk for complications after cranioplasty.


Journal of Neurosurgery | 2012

Optimal timing of autologous cranioplasty after decompressive craniectomy in children

Mark P. Piedra; Eric Thompson; Nathan R. Selden; Brian T. Ragel; Daniel J. Guillaume

OBJECT The object of this study was to determine if early cranioplasty after decompressive craniectomy for elevated intracranial pressure in children reduces complications. METHODS Sixty-one consecutive cases involving pediatric patients who underwent autologous cranioplasty after decompressive craniectomy for raised intracranial pressure at a single academic childrens hospital over 15 years were studied retrospectively. RESULTS Sixty-one patients were divided into early (< 6 weeks; 28 patients) and late (≥ 6 weeks; 33 patients) cranioplasty cohorts. The cohorts were similar except for slightly lower age in the early (8.03 years) than the late (10.8 years) cranioplasty cohort (p < 0.05). Bone resorption after cranioplasty was significantly more common in the late (42%) than the early (14%) cranioplasty cohort (p < 0.05; OR 5.4). No other complication differed in incidence between the cohorts. CONCLUSIONS After decompressive craniectomy for raised intracranial pressure in children, early (< 6 weeks) cranioplasty reduces the occurrence of reoperation for bone resorption, without altering the incidence of other complications.


Surgical Neurology International | 2014

Timing of cranioplasty after decompressive craniectomy for trauma.

Mark P. Piedra; Andrew N. Nemecek; Brian T. Ragel

Background: The optimal timing of cranioplasty after decompressive craniectomy for trauma is unknown. The aim of this study was to determine if early cranioplasty after decompressive craniectomy for trauma reduces complications. Methods: Consecutive cases of patients who underwent autologous cranioplasty after decompressive craniectomy for trauma at a single Level I Trauma Center were studied in a retrospective 10 year data review. Associations of categorical variables were compared using Chi-square test or Fishers exact test. Results: A total of 157 patients were divided into early (<12 weeks; 78 patients) and late (≥12 weeks; 79 patients) cranioplasty cohorts. Baseline characteristics were similar between the two cohorts. Cranioplasty operative time was significantly shorter in the early (102 minutes) than the late (125 minutes) cranioplasty cohort (P = 0.0482). Overall complication rate in both cohorts was 35%. Infection rates were lower in the early (7.7%) than the late (14%) cranioplasty cohort as was bone graft resorption (15% early, 19% late), hydrocephalus rate (7.7% early, 1.3% late), and postoperative hematoma incidence (3.9% early, 1.3% late). However, these differences were not statistically significant. Patients <18 years of age were at higher risk of bone graft resorption than patients ≥18 years of age (OR 3.32, 95% CI 1.25-8.81; P = 0.0162). Conclusions: After decompressive craniectomy for trauma, early (<12 weeks) cranioplasty does not alter the incidence of complication rates. In patients <18 years of age, early (<12 weeks) cranioplasty increases the risk of bone resorption. Delaying cranioplasty (≥12 weeks) results in longer operative times and may increase costs.


Cerebrovascular Diseases | 2009

Molecular Imaging with Targeted Contrast Ultrasound

Mark P. Piedra; Achim Allroggen; Jonathan R. Lindner

Molecular imaging with contrast-enhanced ultrasound uses targeted microbubbles that are retained in diseased tissue. The resonant properties of these microbubbles produce acoustic signals in an ultrasound field. The microbubbles are targeted to diseased tissue by using certain chemical constituents in the microbubble shell or by attaching disease-specific ligands such as antibodies to the microbubble. In this review, we discuss the applications of this technique to pathological states in the cerebrovascular system including atherosclerosis, tumor angiogenesis, ischemia, intravascular thrombus, and inflammation.


Spine | 2013

Complications After Surgery for Lumbar Stenosis in a Veteran Population

Richard A. Deyo; David Hickam; Jonathan P. Duckart; Mark P. Piedra

Study Design. Secondary analysis of the prospectively collected Veterans Affairs National Surgical Quality Improvement Program database. Objective. Determine rates of major medical complications, wound complications, and mortality among patients undergoing surgery for lumbar stenosis and examine risk factors for these complications. Summary of Background Data. Surgery for spinal stenosis is concentrated among older adults, in whom complications are more frequent than among middle-aged patients. Many studies have focused on infections or device complications, but fewer studies have focused on major cardiopulmonary complications, using prospectively collected data. Methods. We identified patients who underwent surgery for a primary diagnosis of lumbar stenosis between 1998 and 2009 from the Veterans Affairs National Surgical Quality Improvement Program database. We created a composite of major medical complications, including acute myocardial infarction, stroke, pulmonary embolism, pneumonia, systemic sepsis, coma, and cardiac arrest. Results. Among 12,154 eligible patients, major medical complications occurred in 2.1%, wound complications in 3.2%, and 90-day mortality in 0.6%. Major medical complications, but not wound complications, were strongly associated with age. American Society of Anesthesiologists (ASA) class was a strong predictor of complications. Insulin use, long-term corticosteroid use, and preoperative functional status were also significant predictors. Fusion procedures were associated with higher complication rates than with decompression alone. In logistic regressions, ASA class and age were the strongest predictors of major medical complications (odds ratio for ASA class 4 vs. class 1 or 2: 2.97; 95% confidence interval, 1.68–5.25; P = 0.0002). After adjustment for comorbidity, age, and functional status, fusion procedures remained associated with higher medical complication rates than were decompressions alone (odds ratio = 2.85; 95% confidence interval, 2.14–3.78; P < 0.0001). Conclusion. ASA class, age, type of surgery, insulin or corticosteroid use, and functional status were independent risk factors for major medical complications. These factors may help in selecting patients and planning procedures, improving patient safety. Level of Evidence: 3


British Journal of Neurosurgery | 2010

Optochiasmatic cavernous hemangioma.

David Panczykowski; Mark P. Piedra; Justin S. Cetas; Johnny B. Delashaw

We present a case of an optochiasmatic cavernous hemangioma (OCH) treated by stereotactic radiotherapy that required subsequent surgical resection. Subtotal resection and/or radiotherapy are not curative and can lead to hemorrhage and progressive neuronal insult. We recommend complete surgical resection as the treatment of choice.


Acta Neurochirurgica | 2009

Anterior screw fixation of a dislocated type II odontoid fracture facilitated by transoral and posterior cervical manual reduction

Mark P. Piedra; Matthew A. Hunt; Andrew N. Nemecek

SummaryBackgroundEarly fixation of type II odontoid fractures has been shown to provide high rates of long-term stabilization and osteosynthesis.CaseIn this report, the authors present the case of a patient with a locked type II odontoid fracture treated by anterior screw fixation facilitated by closed transoral and posterior cervical manual reduction.Conclusion While transoral intraoperative reduction of a partially displaced odontoid fracture has previously been described, the authors present the first case utilizing this technique in the treatment of a completely dislocated type II odontoid fracture.


Journal of Graduate Medical Education | 2014

An ACGME Duty Hour Compliant 3-Person Night Float System for Neurological Surgery Residency Programs.

Brian T. Ragel; Mark P. Piedra; Paul Klimo; Kim J. Burchiel; Heidi Waldo; Shirley McCartney; Nathan R. Selden


Journal of Neurosurgery | 2018

Complications following pediatric cranioplasty after decompressive craniectomy: a multicenter retrospective study

Brandon G. Rocque; Bonita S. Agee; Eric Thompson; Mark P. Piedra; Lissa C. Baird; Nathan R. Selden; Stephanie Greene; Christopher P. Deibert; Todd C. Hankinson; Sean M. Lew; Bermans J. Iskandar; Taryn Bragg; David M. Frim; Gerald A. Grant; Nalin Gupta; Kurtis I. Auguste; Dimitrios Nikas; Michael Vassilyadi; Carrie R. Muh; Nicholas M. Wetjen; Sandi Lam


Skull Base Surgery | 2012

Short-Term Risk of Recurrence of Surgically Treated, Radiotherapy-Naive Pituitary Adenomas

Mark P. Piedra; Nicholas D. Coppa; Aclan Dogan; Chris G. Yedinak; Jessica Brzana; Peter E. Andersen; Johnny B. Delashaw; Maria Fleseriu

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Bermans J. Iskandar

University of Wisconsin-Madison

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Bonita S. Agee

University of Alabama at Birmingham

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