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Dive into the research topics where Andrew N. Nemecek is active.

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Featured researches published by Andrew N. Nemecek.


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.


Neurosurgery | 2009

Surgical management of spinal catheter granulomas: operative nuances and review of the surgical literature.

Andrew C. Zacest; Jonathan D. Carlson; Andrew N. Nemecek; Kim J. Burchiel

OBJECTIVESpinal catheter granulomas are a rare and, most likely, underreported complication of intrathecal opioid therapy. Such granulomas can be associated with devastating neurological sequelae if not treated in a timely fashion. Most neurosurgeons, however, are unlikely to have had experience in the surgical management of this condition. CLINICAL PRESENTATIONThe authors present 3 surgical cases of patients with spinal catheter granulomas with neurological deficits. One patients intraoperative video illustrates the challenges of diagnosis, radiological assessment, and surgery for spinal catheter granulomas. INTERVENTIONAll 3 patients had implanted opioid pumps for management of chronic spinal pain secondary to fracture, tethered cord, and back pain. Increasing back pain and a progressive myelopathy was observed in all patients. A clear radiological diagnosis was made more difficult because of instrumentation artifact in 1 case and claustrophobia in another. Computed tomographic myelography was necessary in 1 case. The surgical findings were: 1 extradural catheter with granuloma and 2 intradural catheters encased with granuloma and adherent to the cord. The extradural catheter was trimmed of granuloma and replaced intradurally in 1 case. The patients with intradural catheter granulomas required judicious dissection of the granulomas from the dorsum of the cord, duroplasty, and catheter section. Critical intraoperative stages were recorded and are presented in digital movie format. Two patients had neurological improvement after surgery; however, 1 patient remained paraplegic. The 2 patients with catheter section required opioid withdrawal treatment. CONCLUSIONThe operative management of spinal intrathecal granulomas associated with opioid infusion pumps can be challenging and depends on a high degree of clinical suspicion, imaging results, and operative findings.


Spine | 2013

Postoperative prevertebral soft tissue swelling does not affect the development of chronic dysphagia following anterior cervical spine surgery.

Farbod Khaki; Natalie L. Zusman; Andrew N. Nemecek; Alexander C. Ching; Robert A. Hart; Jung U. Yoo

Study Design. Prospective cohort study. Objective. To characterize the relation between postoperative soft tissue swelling and the development of chronic dysphagia after anterior cervical spine surgery. Chronic dysphagia was defined as dysphagia that persists more than 1 year. Summary of Background Data. Dysphagia is commonly reported in the early postoperative period after anterior cervical spine surgery. Although prevertebral soft tissue swelling (STS) has been hypothesized as a potential risk factor for development of dysphagia, no studies have assessed STS relation to dysphagia that persists more than 1 year. Methods. Sixty-seven patients who underwent elective anterior cervical spine surgery from 2008 to 2011 and completed a dysphagia questionnaire were included in the study. Prevertebral STS was measured at the caudal endplates of C2 and C6 on plain lateral cervical radiographs preoperatively, immediately after, and 6 and 12 weeks postoperatively. The presence and severity of chronic dysphagia was assessed using the Bazaz-Yoo Dysphagia Score. The prevalence of dysphagia in relation to STS was evaluated using the Wilcoxon rank-sum test. Results. By 6 weeks after surgery, 89% of STS at C2 and 97% of STS at C6 had resolved, as compared with preoperative values. The overall dysphagia prevalence in our cohort was 73%, with 48% reporting no or mild symptoms. Moderate symptoms were present in 39% and severe symptoms were present in 13% of the patients. There was no relation between STS measured at all time points compared with the development of chronic dysphagia. Dysphagia did trend toward significance with higher cervical fusions (C4 and above) and as the number of levels fused increased, but STS did not seem to influence this. Conclusion. Postoperative STS is a self-limiting process. The magnitude of STS during the postoperative period does not seem to influence the development of chronic dysphagia. Level of Evidence: 3


Neurology Research International | 2012

Controversies in the Surgical Management of Spinal Cord Injuries

Ahmed M. Raslan; Andrew N. Nemecek

Traumatic spinal cord injury (SCI) affects over 200,000 people in the USA and is a major source of morbidity, mortality, and societal cost. Management of SCI includes several components. Acute management includes medical agents and surgical treatment that usually includes either all or a combination of reduction, decompression, and stabilization. Physical therapy and rehabilitation and late onset SCI problems also play a role. A review of the literature in regard to surgical management of SCI patients in the acute setting was undertaken. The controversy surrounding whether reduction is safe, or not, and whether prereduction magnetic resonance (MR) imaging to rule out traumatic disc herniation is essential is discussed. The controversial role of timing of surgical intervention and the choice of surgical approach in acute, incomplete, and acute traumatic SCI patients are reviewed. Surgical treatment is an essential tool in management of SCI patients and the controversy surrounding the timing of surgery remains unresolved. Presurgical reduction is considered safe and essential in the management of SCI with loss of alignment, at least as an initial step in the overall care of a SCI patient. Future prospective collection of outcome data that would suffice as evidence-based is recommended and necessary.


Neurosurgery | 2008

Superior semicircular canal dehiscence syndrome: Successful treatment with repair of the middle fossa floor: Technical case report

Eric C. Peterson; Daniel A. Lazar; Andrew N. Nemecek; Larry G. Duckert; Robert C. Rostomily

OBJECTIVE Superior semicircular canal dehiscence syndrome has recently been reported as a cause of pressure- or sound-induced oscillopsia (Tullio phenomenon). We report the presentation and successful treatment of 3 patients with superior semicircular dehiscence syndrome by a joint neurosurgical/neuro-otology team. CLINICAL PRESENTATION Patient 1 is a 37-year-old man who presented with complaints of disequilibrium, fullness in the left ear, hearing loss, and oscillopsia when pressure was applied to the left external auditory canal. Patient 2 is a 46-year-old man who presented with complaints of disequilibrium, fullness in the left ear, and blurred vision associated with heavy lifting or straining. On examination, pneumatic otoscopy produced a sense of motion. Patient 3 is a 29-year-old woman who presented with chronic disequilibrium that resulted in frequent falls. She had a positive fistula test on the left, and vertical nystagmus was elicited when pressure was applied to the left ear. In each patient, high-resolution computed tomographic scanning through the temporal bone revealed dehiscence of the superior semicircular canal on the symptomatic side. INTERVENTION In all 3 cases, a subtemporal, extradural approach was performed with repair of the middle fossa floor using calcium phosphate BoneSource (Howmedica Leibinger, Inc., Dallas, TX). All patients recovered well, with resolution of their symptoms. CONCLUSION Superior semicircular canal dehiscence syndrome is a cause of disequilibrium associated with sound or pressure stimuli. The workup includes a detailed history, electronystagmography including Valsalva maneuvers, and a high-resolution computed tomographic scan though the temporal bone. An extradural repair of the middle fossa floor with BoneSource can successfully treat this condition.


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.


Emergency Medicine Clinics of North America | 2009

Optimal management of malignant epidural spinal cord compression.

Hai Sun; Andrew N. Nemecek

Malignant epidural spinal cord compression (MESCC) is a common neurologic complication of cancer. MESCC is a medical emergency that needs rapid diagnosis and treatment to prevent paraplegia. Patients with malignancy who present with new onset of neurologic signs and symptoms should undergo emergent evaluation including magnetic resonance imaging of the entire spine. If MESCC is diagnosed, corticosteroids should be administered. Simultaneously, spine surgery and oncology teams should be immediately consulted. If indicated, patients should undergo maximal tumor resection and stabilization, followed by postoperative radiotherapy. Emerging treatment options such as stereotactic radiosurgery and vertebroplasty may be able to provide some symptomatic relief for patients who are not surgical candidates.


Journal of Neurosurgery | 2010

Traumatic Type III odontoid fracture and severe rotatory atlantoaxial subluxation in a 3-year-old child: Case report

David Panczykowski; Andrew N. Nemecek; Nathan R. Selden

In this report, the authors describe the case of a 3-year-old child with a traumatic Type III odontoid fracture. To their knowledge, this is the first reported case of a true Type III odontoid fracture with atlantoaxial rotatory subluxation in a child. The patient presented with pain and had resisted manipulation of the neck following a motor vehicle crash. Plain cervical radiographs revealed an odontoid fracture, which was confirmed by CT imaging. The left lateral mass of C-1 was rotated anterior to that of C-2 with the displaced odontoid process acting as the pivot point of rotation. The C1-2 alignment was normalized, and the C-2 fracture was reduced completely. The regional anatomy and mechanism of injury, radiographic diagnosis, and management of cervical spine injuries in children are discussed.


World Neurosurgery | 2016

Minimal Access Posterior Approach for Extrapleural Thoracic Sympathectomy: A Cadaveric Study and Cases.

Jeffrey S. Raskin; Jesse J. Liu; Hai Sun; Andrew N. Nemecek; Seshadri Balaji; Ahmed M. Raslan

OBJECTIVEnOperatively, video-assisted thoracoscopic sympathectomy (VATS) involves pleural entry and poses risk in small children and patients with pulmonary disease. A conventional posterior sympathectomy is more invasive than VATS. We investigated a cadaveric feasibility study of a minimal access posterior approach for endoscopic extrapleural sympathectomy and discuss this minimal approach in children with cardiac sympathectomy.nnnMETHODSnA posterior endoscopic extrapleural approach for thoracic sympathectomy was performed using lightly embalmed cadavers; surgical corridor depth, width, and associated pleural violation were recorded. Two pediatric cases undergoing secondary prevention for breakthrough cardiac dysrhythmias using this approach are discussed: case 1, a 9-year-old girl with refractory long QT syndrome; and case 2, a 13-year-old boy with hypertrophic cardiomyopathy.nnnRESULTSnThe cadaveric study supported 100% identification of a craniocaudal-oriented sympathetic chain using an 18-mm tubular retractor, and a 10% pleural violation rate. There were no clinically significant pneumothoracies in either proof of concept cases.nnnCONCLUSIONSnMinimal access posterior extrapleural sympathectomy is feasible to expose the sympathetic chain in the thoracic region with good visualization using either endoscopic or microscopic magnification. Single-position bilateral thoracic sympathectomy can be performed in pediatric patients with life-threatening ventricular arrhythmias. Based on the cadaveric study and the 2 preliminary cases, we believe that a posterior minimal access approach allows safe and effective access to the thoracic sympathetic chain for causes requiring sympathectomy using single positioning, with minimal risk of pneumothorax or Horner syndrome.


Journal of Neurosurgery | 2009

Successful ventricle to direct heart shunt placement as a salvage cerebrospinal fluid diversion technique. Case report.

Eric Thompson; Stephen G. Giles; Howard K. Song; Zachary Litvack; Kiarash J. Golshani; Andrew N. Nemecek

The authors report a complex case in a 35-year-old woman who underwent shunt placement at birth for myelomeningocele. She had previously undergone more than 30 shunt revisions, with placement of the distal catheter in the peritoneum multiple times, and also in the pleura, the gall bladder, and the upper venous system. All shunts had failed and the possible placement sites were now anatomically hostile. A median sternotomy was performed as the next option. The catheter was placed directly into the appendage of the right atrium and secured with a pursestring suture. One month postoperatively, the patient presented with a large pericardial effusion after the distal catheter migrated out of the atrium and into the pericardial space. A repeat sternotomy was performed to drain the pericardial CSF collection. The catheter was reinserted into the atrial appendage, and a tunnel was created in the atrial wall to fix the device more securely. At 1 year postoperatively, the patient had no further symptoms of shunt obstruction or cardiac tamponade, and imaging studies suggested that the shunt system was functional. The authors report the first successful ventricle to direct heart shunt in an adult.

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