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Biomedical subjects

Alan T Villavicencio

Publications and source records attributed to Alan T Villavicencio.

At least 19 recordsLinked to original sources
PubMed2006

Back and neck pain in triathletes.

OBJECT: As the sport of triathlon has continued to grow, increasing numbers of triathletes have presented in the neurosurgery clinics with various spinal disorders. This epidemiological study was undertaken to establish the lifetime incidence of neck and back pain, to gauge the prevalence of discogenic pain, and to identify risk factors among triathletes in the Boulder, Colorado, area. METHODS: A live online questionnaire was developed that was used to collect information about physical characteristics, training habits, athletic status, number of races completed, and back pain among triathletes. The incidence of cervical and/or lumbar discogenic back pain was defined according to the duration of symptoms for the most recent pain episode. The lifetime incidence of low-back pain was 67.8%, with 23.7% of cases possibly being discogenic in origin. The number of triathlons in which the respondents had participated and the presence of previous sports-related injuries were predictive of low-back pain (p = 0.02 and p < 0.00001, respectively). The lifetime incidence of neck pain was 48.3%, with 21.4% of cases being consistent with intervertebral disc involvement. The number of previous sports-related injuries was predictive of neck pain (p < 0.00001), and a strong tendency toward neck pain was observed for athletes with more total years of participation in sports (p = 0.06). CONCLUSIONS: The two main risk factors for long-term spinal problems include sports-related injuries and overuse. The study results definitely support the influence of both mechanisms for low-back pain. Neck pain was associated with an injury event, and a strong (although not statistically significant) tendency toward neck pain was observed in respondents with overuse injuries.

Adolescent↗
PubMed2006

Perioperative complications in transforaminal lumbar interbody fusion versus anterior-posterior reconstruction for lumbar disc degeneration and instability.

OBJECTIVES: Multiple different approaches are used to treat lumbar degenerative disc disease and spinal instability. Both anterior-posterior (AP) reconstructive surgery and transforaminal lumbar interbody fusion (TLIF) provide a circumferential fusion and are considered reasonable surgical options. The purpose of this study was to quantitatively assess clinical parameters such as surgical blood loss, duration of the procedure, length of hospitalization, and complications for TLIF and AP reconstructive surgery for lumbar fusion. METHODS: A retrospective analysis was completed on 167 consecutive cases performed between January 2002 and March 2004. TLIF surgical procedure was performed on 124 patients, including 73 minimally invasive and 51 open cases. AP surgery was performed on 43 patients. Patients were treated for painful degenerative disc disease, facet arthropathy, degenerative instability, and spinal stenosis. RESULTS: The mean operative time for AP reconstruction was 455 minutes, for minimally invasive TLIF 255 minutes, and open TLIF 222 minutes. The mean blood loss for AP fusion surgery was 550 mL, for minimally invasive TLIF 231 mL, and open TLIF 424 mL. The mean hospitalization time for AP reconstruction was 7.2 days, for minimally invasive TLIF 3.1 days, and open TLIF 4.1 days. The total rate of complications was 76.7% for AP reconstruction, including 62.8% major and 13.9% minor complications. The minimally invasive TLIF patients group had the total 30.1% rate of complications, 21.9% of which were minor and 8.2% major complications. There were no major complications in the open TLIF patients group, with 35.3% minor complications. CONCLUSIONS: AP lumbar interbody fusion surgery is associated with a more than two times higher complication rate, significantly increased blood loss, and longer operative and hospitalization times than both percutaneous and open TLIF for lumbar disc degeneration and instability.

Adult↗
PubMed2006

Three-dimensional computed tomographic analysis of the relationship between the arcuate eminence and the superior semicircular canal.

OBJECTIVE: The location of the superior semicircular canal (SSC) is often determined intraoperatively based on its topographic association with the arcuate eminence (AE). This determination is not always possible because of the potential variability in the relationship between these two structures. The goal of this study was to describe the three-dimensional (3-D) relationship between the AE and SSC using 3-D computed tomography (CT) and to evaluate the utility of 3-D CT for preoperative planning for surgical approaches to the middle cranial fossa. METHODS: We studied 11 patients (22 sides) radiographically using 0.8- to 1-mm thick reconstructed CT images. A standard set of structural relationships was measured between the AE, SSC, and other regional landmarks. RESULTS: 3-D CT clearly demonstrated the relationships between traditional landmarks along the petrous ridge and middle cranial fossa. The relationship between the arcuate eminence and SSC was found to be highly variable. The average distance between the tips of the two structures was found to be 5.7 mm (range, 2.7-10.4 mm). CONCLUSIONS: There is significant variability in the relationship between the AE and the SSC. The AE is not a consistent or reliable landmark for identifying the precise position of the SSC. Detailed preoperative information regarding the relationship between the AE, SSC, and other bony landmarks can be easily and quickly assessed using 3-D CT.

Adolescent↗
PubMed2005

Thoracolumbar vertebral reconstruction after surgery for metastatic spinal tumors: long-term outcomes.

OBJECT: Metastatic spinal tumors continue to represent a major problem for patients and treating physicians. The purpose of this study was to assess quantitatively the functional outcome, quality of life, and survival rates of patients after major reconstructive spine surgery. METHODS: A prospective database was established and 58 patients were identified who had undergone thoracolumbar vertebral reconstruction for metastatic spinal tumors between March 1993 and October 1999. Surgical indications included disabling pain (92%) and/or progressive neurological dysfunction (60%). Forty-nine patients (85%) had clinical improvement in pain as determined based on the Oswestry pain scale (p < 0.05); 60% demonstrated improvement in their neurological status. The mean neurological improvement in Frankel grade was 1.2 (p < 0.05). The 12-month survival rate was 65%, and all patients who were ambulatory after surgery remained so until the time of death. Instrumentation failure requiring repeated operation occurred in two patients (3.5%), and in 12 patients (21%) local tumor recurrence necessitated repeated surgery. There were no cases of neurological deficit or death related to surgery. CONCLUSIONS: Major anterior thoracolumbar vertebral reconstruction is an effective treatment for local tumor control. More importantly, the authors have demonstrated that surgical treatment can significantly improve the quality of life by improvement of pain control and maintenance of ambulation during the patient's remaining life span.

Humans↗
PubMed2005

CyberKnife radiosurgery for idiopathic trigeminal neuralgia.

OBJECT: Gamma knife surgery is an accepted treatment option for trigeminal neuralgia (TN). The safety and efficacy of CyberKnife radiosurgery as a treatment option for TN, however, has not been established. METHODS: Forty-one patients were treated between May 2002 and September 2004 for idiopathic TN at Stanford University and the Rocky Mountain CyberKnife Center. Patients with atypical pain, multiple sclerosis, or previous radiosurgical treatment or a follow-up duration of less than 6 months were excluded. Patients were evaluated for the level of pain control, response rate, time to pain relief, occurrence of hypesthesia, and time to pain recurrence with respect to the length of the nerve treated and the maximum and the minimum dose to the nerve margin. Thirty-eight patients (92.7%) experienced initial pain relief at a median of 7 days after treatment (range, 24 hours-4 months). Pain control was ranked as excellent in 36 patients (87.8%), moderate in two (4.9%), and three (7.3%) reported no change. Six (15.8%) of the 38 patients with initial relief experienced a recurrence of pain at a median of 6 months (range 2-8 months). Long-term response after a mean follow-up time of 11 months was found in 32 (78%) of 41. Twenty-one patients (51.2%) experienced numbness after treatment. CONCLUSIONS: CyberKnife radiosurgery for TN has high rates of initial pain control and short latency to pain relief compared with those reported for other radiosurgery systems. The doses used for treatment were safe and effective. Higher prescribed doses were not associated with improvement in pain relief or recurrence rate. The hypesthesia rate was related to the length of the trigeminal nerve treated.

Adult↗
PubMed2005

Intraoperative three-dimensional fluoroscopy-based computerized tomography guidance for percutaneous kyphoplasty.

OBJECT: Percutaneous kyphoplasty is an established method for the treatment of pathological vertebral compression fractures (VCFs). This procedure is usually performed with the aid of biplanar fluoroscopic image guidance. There are currently no published clinical studies in which the use of three-dimensional (3D) image guidance to facilitate this technique has been evaluated. The purpose of this study was to evaluate the efficacy of isocentric fluoroscopy-based navigation for the kyphoplasty procedure, with special reference to operating time and the amount of radiation exposure. METHODS: A prospective clinical study was performed in which 11 consecutive patients with painful pathological VCFs that did not respond to conservative treatment underwent the kyphoplasty procedure. During this procedure, cannulation of the pedicle and vertebral body was performed with the aid of isocentric 3D fluoroscopy visualization. Total operating time and intraoperative fluoroscopy time for this group was compared with a cohort of nine patients who underwent the procedure prior to the availability of isocentric fluoroscopy (only biplanar fluoroscopy was used). Possible complications such as cement extravasations were evaluated during the procedure and on postoperative computerized tomography scans. The mean duration of surgery for the 3D isocentric fluoroscopic guidance group was 60 minutes (range 36-89 minutes) for one-level and 68.5 minutes (range 65-75 minutes) for two-level cases. Because of a learning curve with the equipment, the operating time for the initial cases was significantly longer than with the later ones. Even with the initial cases included, the mean operating time was shorter compared with the biplanar fluoroscopy-assisted procedures, which averaged 69.2 minutes (range 44-113 minutes) for one-level procedures. This difference was not statistically significant. The mean fluoroscopy exposure time was 41.3 seconds (range 25-62 seconds) in the isocentric fluoroscopy-assisted procedures, with an additional 40 seconds of fluoroscopy time used for the 3D fluoroscopy "spin," compared with 293.2 seconds (range 180-400 seconds) in the biplanar fluoroscopy-assisted procedures. The difference was statistically significant (p = 0.02). All pedicles were accessed without difficulty and no complications were encountered in either group of patients. CONCLUSIONS: The main advantage of isocentric fluoroscopy is the significant reduction in radiation exposure for the patient and surgical staff without an increase in the mean operating time. This technique is a significant advancement over biplanar fluoroscopy in this setting.

Adult↗
PubMed2005

Utility of computerized isocentric fluoroscopy for minimally invasive spinal surgical techniques.

OBJECTIVE: The purpose of this study was to prospectively evaluate the clinical utility and accuracy of intraoperative three-dimensional fluoroscopy as an adjunct for the placement of a complex spinal instrumentation. METHODS: The Siemens Iso-C three-dimensional fluoroscopy unit in the combination with the Stealth Treon computer volumetric navigational system was used. A total of 279 spinal instrumentation screws or transpedicular cannulations were performed in 69 patients. Accuracy, operative time, and amount of fluoroscopy utilization time were assessed for transforaminal lumbar interbody fusion (TLIF) and kyphoplasty cases. RESULTS: Only 4 percutaneous transpedicular lumbar screws out of 265 total (1.5%) were malpositioned. Average operative time for TLIF cases was 185 minutes (range 114-311 minutes) for one-level and 292.6 minutes (range 173-390 minutes) for two-level procedures. Biplanar fluoroscopy utilization time was 93 seconds (range 27-280 seconds) for one-level procedures and 216 seconds (range 80-388 seconds) for two-level procedures. Average surgery duration for kyphoplasty was 60 minutes (range 36-79 minutes) for one-level procedures and 68.5 minutes (range 65-75 minutes) for two-level cases. Biplanar fluoroscopy utilization time was 41.3 seconds per case (range 25-62 seconds). CONCLUSIONS: Use of intraoperative three-dimensional fluoroscopy for image guidance in minimally invasive complex spinal instrumentation procedures is feasible and safe. This technique provides excellent visualization of three-dimensional relationships. This potentially results in improved accuracy of screw positioning and the ability to detect misplaced screws prior to wound closure. This technique also potentially results in a significant reduction in radiation exposure for both the patient and the staff.

Adult↗
PubMed2005

Safety of transforaminal lumbar interbody fusion and intervertebral recombinant human bone morphogenetic protein-2.

OBJECT: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is being increasingly used for spinal fusion. There are few data regarding its clinical safety, effectiveness, and clinical outcome when applied on an absorbable collagen sponge (ACS) in conjunction with allograft for transforaminal lumbar interbody fusion (TLIF). METHODS: Seventy-four consecutive patients undergoing TLIF for degenerative disc disease were divided into five groups depending on whether the patient underwent a minimally invasive or open approach, as well as the number of spinal levels surgically treated. Surgery-related data, fusion results, complications, and clinical outcome were evaluated. The mean follow-up duration was 20.6 months (range 14-28 months). The radiographic fusion rate was 100% at 12 and 24 months after the surgery. No bone overgrowth or other complications related to BMP use were demonstrated. CONCLUSIONS: Analysis of the results demonstrated that TLIF combined with a BMP-2-soaked ACS is a feasible, effective, and safe method to promote lumbar fusion. There were no significant intergroup differences in clinical outcome between patients who underwent open compared with minimally invasive procedures. Patient satisfaction rates, however, were higher in the minimally invasive procedure group. The efficacy of BMP-2 was not dependent on which approach was used or the number of spinal levels that were treated.

Absorbable Implants↗
PubMed2004

Endoscopic lateral transpsoas approach to the lumbar spine.

STUDY DESIGN: A description of a novel surgical approach to the lumbar spine and a prospective evaluation of the early surgical outcomes. OBJECTIVES: Describe the early postoperative results and the operative technique of a new, minimally invasive transpsoas approach for anterior fusion of the lumbar spine that minimizes the risk to large vessels and other critical structures. SUMMARY OF BACKGROUND DATA: Standard anterior endoscopic approaches to the lumbar spine require mobilization of the great vessels and sympathetic plexus. Vascular injury and retrograde ejaculation are complications clearly associated with this approach. A retroperitoneal, transpsoas approach to the lumbar spine may reduce these risks. METHODS: From 1996 to 2002, 21 patients (13 females, 8 males; mean age 50.0 years) underwent an endoscopic, retroperitoneal transpsoas approach for exposure of the lumbar spine. Surgical indications included discogenic pain in 14 patients, spinal instability at a level adjacent to a previous fusion in 3 patients, and progressive degenerative scoliosis in 4 patients. Data were reviewed to document the early postoperative results for this procedure. Illustrations were created to clearly describe this approach. RESULTS: Average operative time for the single level cases was 149 minutes (range 120-170 minutes); blood loss was 150 cc (range 50-650); postoperative hospital stay was 4.1 days. At long-term follow-up, visual analogue scale scores had decreased an average of 5.9. Mean follow-up was 3.1 years (range 2 months-6.0 years). Six patients (30%) experienced paresthesias in the groin/thigh region. Five of these same patients also complained of groin/thigh pain (27%). Two patients had symptoms that lasted longer than 1 month. One patient was converted to a mini-open lateral approach. There were no vascular injuries. CONCLUSIONS: Early results show the endoscopic lateral transpsoas approach to the lumbar spine to be a safe, minimally invasive method for anterior fusion of the first through the fourth lumbar vertebrae. Although there is a risk of groin/thigh numbness or pain, and these symptoms are mostly transient. This approach allows for exposure of the lumbar spine without mobilization of the great vessels or sympathetic plexus.

Adult↗
PubMed2003

Successful aqueductal plasty and stenting for tectal plate tumor after failed third ventriculostomy: a case report.

BACKGROUND: Tectal region tumors can lead to hydrocephalus secondary to aqueductal compression. Surgical options for these patients include extracranial cerebrospinal fluid (CSF) shunts, third ventriculostomy, and/or aqueductal plasty. In cases of third ventriculostomy failure, the accepted alternative is an extracranial CSF shunt. We report a patient in whom a repeat third ventriculostomy with aqueductal plasty and stenting was successful after a failed initial third ventriculostomy. CASE PRESENTATION: A 12-year-old patient with hydrocephalus secondary to a tectal tumor presented with headaches and blurry vision. She had no focal neurologic findings. She underwent a third ventriculostomy. Five months after the procedure she had recurrence of her symptoms. Therefore, she underwent a secondary third ventriculostomy with aqueductal plasty and stenting. She has been symptom-free for 1 year. CONCLUSION: Aqueductal plasty with stenting may be an alternative to CSF shunts in some patients with hydrocephalus because of aqueductal compression resulting from tectal tumors.

Brain Neoplasms↗
PubMed2003

MRI-guided stereotactic biopsy in the diagnosis of glioma: comparison of biopsy and surgical resection specimen.

BACKGROUND: Although there has been a dramatic increase in the accessibility and utilization of high-resolution MRI techniques for the evaluation of brain tumors, there is currently only a single report comparing stereotactic brain biopsy specimen to subsequent resection specimen exclusively in the management of gliomas. METHODS: The diagnoses in 43 cases of astrocytic brain tumors were derived using MRI-guided stereotactic biopsy followed by open resection of the lesion. The histologic diagnoses yielded by biopsy were compared with subsequent histologic diagnosis after open tumor resection. All biopsies and histologic diagnoses were made by the same surgeon and pathologist, respectively. RESULTS: In 23 patients undergoing resection <60 days after biopsy, the biopsy diagnosis was consistent with resection diagnosis in 18 cases (79%) and led to the correct treatment in 22 cases (96%). Recurrent glioblastoma multiforme (GBM) was undergraded as anaplastic astrocytoma in 4 patients. GBM was misdiagnosed as radiation necrosis in 1 patient. MR-nonenhancing lesions [10/10 (100%)] yielded histology that correlated with subsequent craniotomy, while only 8/13 (61%) MR-enhancing lesions yielded histology that was consistent with that at craniotomy (p < 0.05). In 20 patients undergoing resection because of radiologic tumor progression (mean 7 months after biopsy), 6/6 (100%) biopsy diagnoses of a specific glioma grade correlated with resection diagnosis, while only 6/14 (43%) biopsy diagnoses of radiation effect correlated with resection diagnosis (p < 0.01). CONCLUSION: MRI-guided stereotactic brain biopsy specimen accurately represents the grade of the larger glioma mass sufficiently to guide subsequent therapy. Enhancement on MR may be a negative prognostic indicator of biopsy accuracy.

Biopsy↗
PubMed2003

Comparison of revision rates following endoscopically versus nonendoscopically placed ventricular shunt catheters.

BACKGROUND: Endoscopic placement of ventriculoperitoneal (VP) shunt catheters in pediatric patients has been increasingly used in an attempt to minimize the unacceptably high rates of revision. Although this procedure carries an increased expense, there is currently no evidence to support an improved long-term outcome. This paper compares the rates of revision following ventricular catheter placement for shunted hydrocephalus with and without the use of endoscopy. METHODS: We retrospectively reviewed the records of all pediatric patients who had undergone shunt placement for hydrocephalus between April 1992 and February 1998. All shunts placed before March 1995 were performed without the endoscope; all subsequent shunts were placed endoscopically. The independent effect of endoscopic versus nonendoscopic shunt placement on subsequent shunt failure was analyzed via multivariate proportional hazards regression model. Multiple logistic regression analyses were used to determine the independent effect of endoscopic placement on subsequent etiology of failure (infection, proximal obstruction, distal malfunction) in the 511 failing shunts. RESULTS: There were 447 pediatric patients who underwent a total of 965 shunt placements or revisions. Six hundred and five (63%) catheters were placed with the use of the endoscope. Three hundred and sixty (37.3%) were placed without the use of the endoscope. Neuroendoscopy did not independently affect the risk of subsequent shunt failure [Hazard Ratio (95% Confidence Interval) = 1.08 (0.84-1.41)]. Endoscopic placement independently decreased the odds [Odds Ratio (95% Confidence Interval) = 0.56 (0.32-0.93)] of proximal obstruction, increased the odds of distal malfunction [1.52 (1.02-2.72)], and was not associated with infection [1.42 (0.78-2.61)]. CONCLUSIONS: Endoscopic assisted ventricular catheter placement decreased the odds of proximal obstruction but failed to improve overall shunt survival in this 6 year experience.

Cerebral Ventricles↗
PubMed2003

Use of the peak troponin value to differentiate myocardial infarction from reversible neurogenic left ventricular dysfunction associated with aneurysmal subarachnoid hemorrhage.

OBJECT: Differentiating myocardial infarction (MI) from reversible neurogenic left ventricular dysfunction (stunned myocardium [SM]) associated with aneurysmal subarachnoid hemorrhage (SAH) is critical for early surgical intervention. The authors hypothesized that the cardiac troponin (cTn) trend and/or echocardiogram could be used to differentiate between the two entities. METHODS: A retrospective study was conducted for the period between 1995 and 2000. All patients included in the study met the following criteria: 1) no history of cardiac problems; 2) new onset of abnormal cardiac function (ejection fraction [EF] < 40% on echocardiograms); 3) serial cardiac markers (cTn and creatine kinase MB isoform [CK-MB]); 4) surgical intervention for their aneurysm; and 5) cardiac output monitoring either by repeated echocardiograms or invasive hemodynamic monitoring during the first 4 days post-SAH when the patients were euvolemic. Of the 350 patients with SAH, 10 (2.9%) had severe cardiac dysfunction. Of those 10, six were women and four were men. The patients' mean age was 53.5 years (range 29-75 years) and their SAH was classified as Hunt and Hess Grade III or IV. Aneurysm distribution was as follows: basilar artery tip (four); anterior communicating artery (two); middle cerebral artery (one); posterior communicating artery (two); and posterior inferior cerebellar artery (one). The mean EFonset was 33%. The changes on echocardiograms in these patients did not match the findings on electrocardiograms (EKGs). Within 4.5 days, dramatic improvement was seen in cardiac output (from 4.93 +/- 1.16 L/minute to 7.74 +/- 0.88 L/minute). Compared with historical controls in whom there were similar levels of left ventricular dysfunction after MI, there was no difference in peak CK-MB. A 10-fold difference, however, was noted in cTn values (0.22 +/- 0.25 ng/ml; control 2.8 ng/ml; p < 0.001). CONCLUSIONS: The authors determined the following: 1) that the CK-MB trend does not allow differentiation between SM and MI; 2) that echocardiograms revealing significant inconsistencies with EKGs are indicative of SM; and 3) that cTn values less than 2.8 ng/ml in patients with EFs less than 40% are consistent with SM.

Adult↗
PubMed2002

A new millenium for spinal cord regeneration: growth-associated genes.

INTRODUCTION: Neurons surviving spinal cord injury undergo extensive reorganization that may result in the formation of functional synaptic contacts. Many neurons, however, fail to activate the necessary mechanisms for successful regeneration. In this review, we discuss the implications of growth cone genes that we have correlated with successful spinal cord axonal regeneration. METHOD: Factors that inhibit regeneration, and activation of genes that promote it are discussed. RESULTS/DISCUSSION: The early progress n understanding mechanisms that seem to promote or inhibit regeneration in the central nervous system may have significant clinical utility in the future.

Animals↗
PubMed2002

Posterior atlantoaxial stabilization: new alternative to C1-2 transarticular screws.

OBJECT: Surgical treatment of atlantoaxial instability has evolved to include various posterior wiring techniques including Brooks, Gallie, and Sonntag fusions in which success rates range from 60 to 100%. The Magerl-Seemans technique in which C1-2 transarticular screws are placed results in fusion rates between 87 and 100%. This procedure is technically demanding and requires precise knowledge of the course of the vertebral arteries (VAs). The authors introduce a new C1-2 fixation procedure in which C-1 lateral mass and C-2 pedicle screws are placed that may have advantages over C1-2 transarticular screw constructs. METHODS: A standard posterior C1-2 exposure is obtained. Polyaxial C-2 pedicle screws and C-1 lateral mass screws are placed bilaterally. Rods are connected to the screws and secured using locking nuts. A cross-link is then placed. Fusion can be performed at the atlantoaxial joint by elevating the C-2 nerve root. The technique for this procedure has been used in four cases of atlantoaxial instability at the author's institution. There have been no C-2 nerve root- or VA-related injuries. No cases of construct failure have been observed in the short-term follow up period. CONCLUSIONS: Atlantoaxial lateral mass and axial pedicle screw fixation offers an alternative means of achieving atlantoaxial fusion. The technique is less demanding than that required for transarticular screw placement and may avoid the potential complication of VA injury. The cross-linked construct is theoretically stable in flexion, extension, and rotation. Laminectomy or fracture of the posterior elements does not preclude use of this fixation procedure.

Aged, 80 and over↗
PubMed2002

De novo cerebral arteriovenous malformation: case report.

OBJECTIVE AND IMPORTANCE: Arteriovenous malformations (AVMs) are generally thought to have a congenital cause. This is the first report of an angiographically proven de novo cerebral AVM in an adult patient without previous vascular abnormality. CLINICAL PRESENTATION: A 26-year-old African-American woman developed multiple cranial nerve deficits and ataxia over the course of a few days after a streptococcal throat infection. T2-weighted magnetic resonance imaging scans revealed a hyperintense signal in the midbrain with extension into the diencephalon. A cerebral angiogram performed at that time to exclude vasculitis revealed normal cerebral vasculature. The patient was treated with corticosteroids, and symptoms resolved. Subsequently, at the age of 32, this patient presented with a severe headache and emesis, but with no focal neurological deficit. INTERVENTION: The patient's cranial computed tomographic and magnetic resonance imaging scans revealed a right posterior temporal intraparenchymal hemorrhage, and cerebral angiography revealed a new 3- by 2-cm AVM. The patient underwent microsurgical resection of the AVM and associated hematoma. Postoperative angiography revealed no evidence of residual AVM. CONCLUSION: This study details the case of a woman who developed a de novo cerebral AVM during a 6-year period. This report challenges the conventional belief that all AVMs have a congenital cause.

Adult↗
PubMed2002

Cerebrospinal fluid shunt survival and etiology of failures: a seven-year institutional experience.

BACKGROUND: Innovations in shunt technology and neuroendoscopy have been increasingly applied to shunt management. However, the relative life span of shunts and the etiology of shunt failure have not been characterized recently. METHODS: We reviewed the records of all shunting procedures at our institution between January 1992 and December 1998. Independent predictors of shunt failure were analyzed via multivariate Cox regression analysis in 836 shunting procedures. Independent predictors of the etiology of failure (infection, proximal obstruction, distal malfunction) were analyzed via multivariate logistic regression analysis in the 383 shunts which failed. RESULTS: A total of 353 pediatric patients underwent 308 shunt placements and 528 revisions. The risk (hazard ratio; HR) of shunt failure decreased as a function of time in both primary placements and revised shunts. In failed shunts, the odds of infection decreased 4-fold per year of shunt function, while the odds of distal malfunction increased 1.45-fold per year. Increasing number of shunt revisions (HR 1.31, p < 0.05), decreasing patient age in years (HR 1.04, p < 0.001), gestational age <40 weeks (HR 2.15, p < 0.001) but not the etiology of hydrocephalus were associated with an increased risk of shunt failure. Revisions versus primary placements, Dandy-Walker cysts and gestational age <40 weeks were independently associated with proximal, distal and infectious causes of failure, respectively. CONCLUSIONS: The long-term shunt revision rates observed here are similar to those reported over the past 2 decades. Shunt life span remains poorer in shunt revisions and in younger patients. Patient characteristics may suggest a specific risk and mechanism of failure, aiding in the long-term management of shunted hydrocephalus.

Cerebrospinal Fluid Shunts↗