Marion L Walker | University of Utah (original) (raw)

Papers by Marion L Walker

Research paper thumbnail of Neural Tube Defects Neural Tube Defects

Research paper thumbnail of Role of dorsal rhizotomy in spinal cord injury-induced spasticity

Journal of neurosurgery. Pediatrics, 2014

Selective dorsal rhizotomy may have a role in the management of spinal cord injury (SCI)-induced ... more Selective dorsal rhizotomy may have a role in the management of spinal cord injury (SCI)-induced spasticity. Spasticity and spasms are common sequelae of SCI in children. Depending on the clinical scenario, treatments may include physical and occupational therapy, oral medications, chemodenervation, and neurosurgical interventions. Selective dorsal rhizotomy (SDR) is used in the management of spasticity in selected children with cerebral palsy, but, to the authors' knowledge, its use has not been reported in children with SCI. The authors describe the cases of 3 pediatric patients with SCI and associated spasticity treated with SDR. Two of the 3 patients have had significant long-term improvement in their preoperative spasticity. Although the third patient also experienced initial relief, his spasticity quickly returned to its preoperative severity, necessitating additional therapies. Selective dorsal rhizotomy may have a place in the treatment of selected children with spastici...

Research paper thumbnail of A 14-Year-Old Female with Decreasing Visual Acuity, Severe Headache, Nausea and Vomiting

Pediatric Neurosurgery, Feb 1, 2001

Research paper thumbnail of Clinicopathological review: tumefactive demyelination in a 12-year-old girl

Neurosurgery, May 1, 2005

Dr. Anderson: The patient is a 12 year-old, right-handed girl without significant past medical or... more Dr. Anderson: The patient is a 12 year-old, right-handed girl without significant past medical or surgical history who developed the acute onset of right foot weakness approximately 10 days before admission. After sitting on the couch watching television, she tried to stand and ...

Research paper thumbnail of A new Hydrocephalus Clinical Research Network protocol to reduce cerebrospinal fluid shunt infection

Journal of neurosurgery. Pediatrics, Jan 18, 2015

OBJECT In a previous report by the same research group (Kestle et al., 2011), compliance with an ... more OBJECT In a previous report by the same research group (Kestle et al., 2011), compliance with an 11-step protocol was shown to reduce CSF shunt infection at Hydrocephalus Clinical Research Network (HCRN) centers (from 8.7% to 5.7%). Antibiotic-impregnated catheters (AICs) were not part of the protocol but were used off protocol by some surgeons. The authors therefore began using a new protocol that included AICs in an effort to reduce the infection rate further. METHODS The new protocol was implemented at HCRN centers on January 1, 2012, for all shunt procedures (excluding external ventricular drains [EVDs], ventricular reservoirs, and subgaleal shunts). Procedures performed up to September 30, 2013, were included (21 months). Compliance with the protocol and outcome events up to March 30, 2014, were recorded. The definition of infection was unchanged from the authors' previous report. RESULTS A total of 1935 procedures were performed on 1670 patients at 8 HCRN centers. The over...

Research paper thumbnail of Pediatric skull base surgery: 2. Experience and outcomes in 55 patients

Pediatric Neurosurgery, Feb 1, 2003

In the second of these two articles, we will discuss our clinical experience with skull base surg... more In the second of these two articles, we will discuss our clinical experience with skull base surgery in the pediatric population. We present a retrospective analysis of 55 patients less than 16 years of age who underwent skull base surgical approaches at the Primary Children's Medical Center or the University of Utah Medical Center between January 1992 and April 1999. There were 30 boys and 25 girls (mean age 9.8 years). Patient follow-up averaged 58 months. Most patients had pathology that required either an anterior or anterolateral approach; 6 patients underwent a far-lateral or a transpetrosal exposure. Thirty-five procedures were performed by a neurosurgeon, a pediatric otolaryngologist performed 11 procedures, and 10 procedures were performed by both services together. Ninety-six percent of patients (n = 53) had a Glasgow Outcome Score of 4 or 5. Complications included 4 sustained cranial nerve palsies and 2 hemipareses. There were no CSF leaks, infections or deaths. Patients with sellar region pathology had a disproportionately higher incidence of postoperative morbidity. We conclude that in selected pediatric cases, skull base surgical techniques can be performed effectively and safely with the use of multidisciplinary teams. To implement these techniques, knowledge of their limitations and of the anatomical differences between the adult and pediatric cranial base is essential.

Research paper thumbnail of Medical Management of Head Injuries in Neonates and Infants

Principles of Pediatric Neurosurgery, 1986

Research paper thumbnail of It's everything else you do...': Alumni views on extracurricular activities and employability

Active Learning in Higher Education, 2015

ABSTRACT This article explores students’ extracurricular activities and, uniquely, their short- a... more ABSTRACT This article explores students’ extracurricular activities and, uniquely, their short- and long-term effects on employability. Drawing on the literature, six research questions are identified. A questionnaire and interviews with alumni provide the quantitative and qualitative information needed. The effects of different extracurricular activities and the skills and qualities they promote are demonstrated for early- and later-career jobs, as are the complementary effects for employability of degree schemes and extracurricular activities. Alumni who are now recruiters of staff use their double perspective to explain the role extracurricular activities have played in their lives and now as professional recruiters. The paper shows how the alumni of any university could share these insights with undergraduates.

Research paper thumbnail of Poster 532 Validation of a Long-Term Post-Stroke Checklist

Research paper thumbnail of Stereotactic endoscopic placement of third ventricle catheter for long-term infusion of baclofen in patients with secondary generalized dystonia

Journal of neurosurgery. Pediatrics, 2012

Continuous infusion of baclofen is a treatment option for severe generalized dystonia. Catheter i... more Continuous infusion of baclofen is a treatment option for severe generalized dystonia. Catheter insertion within the third ventricle has been described as an alternative to standard intrathecal placement to maximize intracranial concentrations of baclofen. The authors describe their experience with a novel technique for stereotactic endoscopic insertion of baclofen infusion catheters in the third ventricle in 3 patients with severe secondary generalized dystonia. Insertion was successful in all 3 patients, and all of them experienced significant improvement in dystonia scores on the Barry-Albright Dystonia Scale. Follow-up ranged from 5.5 to 7 months (mean 6 months), and no mechanical complications or CSF leaks were observed. The stereotactic endoscopic insertion of a baclofen infusion catheter into the third ventricle appears to be a safe method for continuous intraventricular baclofen infusion in patients with generalized secondary dystonia.

Research paper thumbnail of Shunt failure due to intracranial migration of BioGlide ventricular catheters

Journal of neurosurgery. Pediatrics, 2011

In late 2008, the authors recognized a new type of ventriculoperitoneal shunt failure specific to... more In late 2008, the authors recognized a new type of ventriculoperitoneal shunt failure specific to the Bio-Glide Snap Shunt ventricular catheters. This prompted a retrospective review of the patient cohort and resulted in a recall by the FDA in the US. After the index cases were identified, the FDA was notified by the hospital, leading to a recall of the product. Hospital operative logs were used to identify patients in whom the affected products were used. A letter describing the risk was sent to all patients offering a free screening CT scan to look for disconnection. A call center was established to respond to patient questions, and an informational video was made available on the hospital website. The authors reviewed the records of the index cases and other cases subsequently identified. Seven index cases and an additional 16 cases of disconnection were identified in the 466 patients in whom a BioGlide Snap Shunt ventricular catheter had been implanted. Mean time to disconnectio...

Research paper thumbnail of The posterior petrosal approach: technique and applications in pediatric neurosurgery

Journal of neurosurgery. Pediatrics, 2009

Various lesions occur in deep locations or at the skull base in pediatric patients and require sk... more Various lesions occur in deep locations or at the skull base in pediatric patients and require skull base approaches for resection. Skull base surgery confers the advantages of improved line of sight, a wider operative corridor, and reduced brain retraction. The posterior petrosal approach provides simultaneous access to lesions in the posterior middle fossa and posterior fossa from the top of the clivus to the level of the jugular foramen. It allows visualization of the ventrolateral brainstem and may be combined with various other supra- and infratentorial approaches, thus giving the surgeon a wide array of access routes to the lesion. The authors conducted a retrospective review of all cases involving pediatric patients undergoing a posterior petrosal approach, either alone or in combination with other cranial approaches. Preoperative and postoperative data were collected, including presentation, neurological examination, imaging findings, pathological condition, operative detail...

Research paper thumbnail of Risk factors and rates of bone flap resorption in pediatric patients after decompressive craniectomy for traumatic brain injury

Journal of Neurosurgery: Pediatrics, 2013

Decompressive craniectomy with subsequent autologous cranioplasty, or the replacement of the nati... more Decompressive craniectomy with subsequent autologous cranioplasty, or the replacement of the native bone flap, is often used for pediatric patients with traumatic brain injury (TBI) who have a mass lesion and intractable intracranial hypertension. Bone flap resorption is common after bone flap replacement, necessitating additional surgery. The authors reviewed their large database of pediatric patients with TBI who underwent decompressive craniectomy followed by bone flap replacement to determine the rate of bone flap resorption and identify associated risk factors. A retrospective cohort chart review was performed to identify long-term survivors who underwent decompressive craniectomy for severe TBI with bone flap replacement from January 1, 1996, to December 31, 2011. The risk factors investigated in a univariate statistical analysis were age, sex, underlying parenchymal contusion, Glasgow Coma Scale score on arrival, comminuted skull fracture, posttraumatic hydrocephalus, bone flap wound infection, and freezer time (the amount of time the bone flap was stored in the freezer before replacement). A multivariate logistic regression model was then used to determine which of these were independent risk factors for bone flap resorption. Bone flap replacement was performed at an average of 2.1 months after decompressive craniectomy. Of the 54 patients identified (35 boys, 19 girls; mean age 6.2 years), 27 (50.0%) experienced bone flap resorption after an average of 4.8 months. Underlying parenchymal contusion, comminuted skull fracture, age ≤ 2.5 years, and posttraumatic hydrocephalus were significant, or nearly significant, on univariate analysis. Multivariate analysis identified underlying contusion (p = 0.004, OR 34.4, 95% CI 3.0-392.7), comminuted skull fractures (p = 0.046, OR 8.5, 95% CI 1.0-69.6), posttraumatic hydrocephalus (p = 0.005, OR 35.9, 95% CI 2.9-436.6), and age ≤ 2.5 years old (p = 0.01, OR 23.1, 95% CI 2.1-257.7) as independent risk factors for bone flap resorption. After decompressive craniectomy for pediatric TBI, half of the patients (50%) who underwent bone flap replacement experienced resorption. Multivariate analysis indicated young age (≤ 2.5 years), hydrocephalus, underlying contusion as opposed to a hemispheric acute subdural hematoma, and a comminuted skull fracture were all independent risk factors for bone flap resorption. Freezer time was not found to be associated with bone flap resorption.

Research paper thumbnail of Spinal arteriovenous fistulas in children with hereditary hemorrhagic telangiectasia

Journal of Neurosurgery: Pediatrics, 2012

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant angiodysplasia with high pen... more Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant angiodysplasia with high penetrance and variable expression. The manifestations of HHT are often age related, and spinal arteriovenous fistula (AVF) may be the initial presentation of HHT in young children. Because spinal AVFs are rarely reported, however, screening is not incorporated into current clinical recommendations for the treatment of patients with HHT. The authors describe 2 cases of children younger than 2 years of age with acute neurological deterioration in the context of a spinal AVF and in whom HHT was subsequently diagnosed. One patient presented with intraventricular and subarachnoid hemorrhage and the other with acute thrombosis of an intramedullary varix. These cases highlight the potential for significant neurological morbidity from a symptomatic AVF in very young children with HHT. Given the lack of data regarding the true incidence and natural history of these lesions, these cases raise the question of whether spinal cord imaging should be incorporated into screening recommendations for patients with HHT.

Research paper thumbnail of Factors associated with ventricular catheter movement and inaccurate catheter location: post hoc analysis of the Hydrocephalus Clinical Research Network Ultrasound-Guided Shunt Placement study

Journal of Neurosurgery: Pediatrics, 2014

Shunt survival may improve when ventricular catheters are placed into the frontal horn or trigone... more Shunt survival may improve when ventricular catheters are placed into the frontal horn or trigone of the lateral ventricle. However, techniques for accurate catheter placement have not been developed. The authors recently reported a prospective study designed to test the accuracy of catheter placement with the assistance of intraoperative ultrasound, but the results were poor (accurate placement in 59%). A major reason for the poor accurate placement rate was catheter movement that occurred between the time of the intraoperative ultrasound image and the first postoperative scan (33% of cases). The control group of non-ultrasound using surgeons also had a low rate of accurate placement (accurate placement in 49%). The authors conducted an exploratory post hoc analysis of patients in their ultrasound study to identify factors associated with either catheter movement or poor catheter placement so that improved surgical techniques for catheter insertion could be developed. The authors investigated the following risk factors for catheter movement and poor catheter placement: age, ventricular size, cortical mantle thickness, surgeon experience, surgeon experience with ultrasound prior to trial, shunt entry site, shunt hardware at entry site, ventricular catheter length, and use of an ultrasound probe guide for catheter insertion. Univariate analysis followed by multivariate logistic regression models were used to determine which factors were independent risk factors for either catheter movement or inaccurate catheter location. In the univariate analyses, only age < 6 months was associated with catheter movement (p = 0.021); cortical mantle thickness < 1 cm was near-significant (p = 0.066). In a multivariate model, age remained significant after adjusting for cortical mantle thickness (OR 8.35, exact 95% CI 1.20-infinity). Univariate analyses of factors associated with inaccurate catheter placement showed that age < 6 months (p = 0.001) and a posterior shunt entry site (p = 0.021) were both associated with poor catheter placement. In a multivariate model, both age < 6 months and a posterior shunt entry site were independent risk factors for…

Research paper thumbnail of Selective dorsal rhizotomy in children with spastic hemiparesis

Journal of Neurosurgery: Pediatrics, 2010

Neurological conditions including cerebral palsy, brain injury, and stroke often result in severe... more Neurological conditions including cerebral palsy, brain injury, and stroke often result in severe spasticity, which can lead to significant deformity and interfere with function. Treatments for spasticity include oral medications, intramuscular botulinum toxin type A injections, orthopedic surgeries, intrathecal baclofen pump implantation, and selective dorsal rhizotomy (SDR). Selective dorsal rhizotomy, which has been well studied in children with spastic diplegia, results in significant reduction in spasticity and improved function in children. To the authors' knowledge, there are no published outcome data for SDR in patients with spastic hemiparesis. The object of this study was to examine the effects of SDR on spastic hemiparesis. A 2-year study was undertaken including all children with spastic hemiparesis who underwent SDR at the authors' institution. The degree of spasticity, as measured by the Modified Ashworth Scale or quality of gait rated using the visual gait assessment scale, the gait parameters, and velocity were compared in patients before and after undergoing SDR. Thirteen children (mean age 6 years 7 months) with spastic hemiparesis underwent SDR performed by the same surgeon during a 2-year period. All of the patients had a decrease in tone in the affected lower extremity after the procedure. The mean reduction in tone in 4 muscle groups (hip adductors, knee flexors, knee extensors, and ankle plantar flexors) according to the modified Ashworth scale score was 2.6 ± 1.26 (p < 0.0001). The quality of gait was assessed in 7 patients by using the visual gait assessment scale. This score improved in 6 patients and remained the same in 1. Stride length and gait velocity were measured in 4 children. Velocity increased in 3 patients and decreased in a 3-year-old child. Parents and clinicians reported an improvement in quality of gait after the procedure. Stride length increased bilaterally in 3 patients and increased on one side and decreased on the other in the other patient. Selective dorsal rhizotomy showed efficacy in the treatment of spastic hemiparesis in children. All of the patients had decreased tone after SDR as measured by the modified Ashworth scale. The majority of patients had qualitative and quantitative improvements in gait.

Research paper thumbnail of A standardized protocol to reduce cerebrospinal fluid shunt infection: The Hydrocephalus Clinical Research Network Quality Improvement Initiative

Journal of Neurosurgery: Pediatrics, 2011

Research paper thumbnail of No significant improvement in the rate of accurate ventricular catheter location using ultrasound-guided CSF shunt insertion: a prospective, controlled study by the Hydrocephalus Clinical Research Network

Journal of Neurosurgery: Pediatrics, 2013

Cerebrospinal fluid shunt ventricular catheters inserted into the frontal horn or trigone are ass... more Cerebrospinal fluid shunt ventricular catheters inserted into the frontal horn or trigone are associated with prolonged shunt survival. Developing surgical techniques for accurate catheter insertion could, therefore, be beneficial to patients. This study was conducted to determine if the rate of accurate catheter location with intraoperative ultrasound guidance could exceed 80%. The authors conducted a prospective, multicenter study of children (< 18 years) requiring first-time treatment for hydrocephalus with a ventriculoperitoneal shunt. Using intraoperative ultrasound, surgeons were required to target the frontal horn or trigone for catheter tip placement. An intraoperative ultrasound image was obtained at the time of catheter insertion. Ventricular catheter location, the primary outcome measure, was determined from the first postoperative image. A control group of patients treated by nonultrasound surgeons (conventional surgeons) were enrolled using the same study criteria. Conventional shunt surgeons also agreed to target the frontal horn or trigone for all catheter insertions. Patients were triaged to participating surgeons based on call schedules at each center. A pediatric neuroradiologist blinded to method of insertion, center, and surgeon determined ventricular catheter tip location. Eleven surgeons enrolled as ultrasound surgeons and 6 as conventional surgeons. Between February 2009 and February 2010, 121 patients were enrolled at 4 Hydrocephalus Clinical Research Network centers. Experienced ultrasound surgeons (> 15 cases prior to study) operated on 67 patients; conventional surgeons operated on 52 patients. Experienced ultrasound surgeons achieved accurate catheter location in 39 (59%) of 66 patients, 95% CI (46%-71%). Intraoperative ultrasound images were compared with postoperative scans. In 32.7% of cases, the catheter tip moved from an accurate location on the intraoperative ultrasound image to an inaccurate location on the postoperative study. This was the most significant factor affecting accuracy. In comparison, conventional surgeons achieved accurate location in 24 (49.0%) of 49 cases (95% CI [34%-64%]). The shunt survival rate at 1 year was 70.8% in the experienced ultrasound group and 66.9% in the conventional group (p = 0.66). Ultrasound surgeons had more catheters surrounded by CSF (30.8% vs 6.1%, p = 0.0012) and away from the choroid plexus (72.3% vs 58.3%, p = 0.12), and fewer catheters in the brain (3% vs 22.4%, p = 0.0011) and crossing the midline (4.5% vs 34.7%, p < 0.001), but they had a higher proportion of postoperative pseudomeningocele (10.1% vs 3.8%, p = 0.30), wound dehiscence (5.8% vs 0%, p = 0.13), CSF leak (10.1% vs 1.9%, p = 0.14), and shunt infection (11.6% vs 5.8%, p = 0.35). Ultrasound-guided shunt insertion as performed in this study was unable to consistently place catheters into the frontal horn or trigone. The technique is safe and achieves outcomes similar to other conventional shunt insertion techniques. Further efforts to improve accurate catheter location should focus on prevention of catheter migration that occurs between intraoperative placement and postoperative imaging. Clinical trial registration no.: NCT01007786 ( ClinicalTrials.gov ).

Research paper thumbnail of Adjustment and malfunction of a programmable valve after exposure to toy magnets. Case report

Journal of neurosurgery, 2004

Inadvertent adjustments and malfunctions of programmable valves have been reported in cases in wh... more Inadvertent adjustments and malfunctions of programmable valves have been reported in cases in which patients have encountered powerful electromagnetic fields such as those involved in magnetic resonance imaging, but the effects of small magnetic fields are not well known. The authors present a case in which a child playing with a collection of commercially available toy magnets altered the pressure setting of an implanted valve and may have caused its permanent malfunction.

Research paper thumbnail of Complications of intracranial pressure monitoring in children with head trauma

Journal of neurosurgery, 2004

Intracranial pressure (ICP) monitoring has become routine in the management of patients with trau... more Intracranial pressure (ICP) monitoring has become routine in the management of patients with traumatic brain injury (TBI). Many surgeons prefer to use external ventricular drains (EVDs) over fiberoptic monitors to measure ICP because of the added benefit of cerebrospinal fluid drainage. The purpose of this study was to examine a consecutive series of children with TBI and compare the incidence of complications after placement of an EVD, a fiberoptic intraparencyhmal monitor, or both. A retrospective chart review was conducted to identify children with TBI who met the criteria for insertion of an ICP monitor. All patients underwent head CT scanning on admission and after placement of an ICP monitor. During a 5-year period 80 children met the criteria for inclusion in the study. Eighteen children (22.5%) underwent EVD placement only, 18 (22.5%) underwent placement of a fiberoptic device only, and 44 (55%) received both. A total of 62 fiberoptic devices (48%) were inserted, and 68 EVDs...

Research paper thumbnail of Neural Tube Defects Neural Tube Defects

Research paper thumbnail of Role of dorsal rhizotomy in spinal cord injury-induced spasticity

Journal of neurosurgery. Pediatrics, 2014

Selective dorsal rhizotomy may have a role in the management of spinal cord injury (SCI)-induced ... more Selective dorsal rhizotomy may have a role in the management of spinal cord injury (SCI)-induced spasticity. Spasticity and spasms are common sequelae of SCI in children. Depending on the clinical scenario, treatments may include physical and occupational therapy, oral medications, chemodenervation, and neurosurgical interventions. Selective dorsal rhizotomy (SDR) is used in the management of spasticity in selected children with cerebral palsy, but, to the authors' knowledge, its use has not been reported in children with SCI. The authors describe the cases of 3 pediatric patients with SCI and associated spasticity treated with SDR. Two of the 3 patients have had significant long-term improvement in their preoperative spasticity. Although the third patient also experienced initial relief, his spasticity quickly returned to its preoperative severity, necessitating additional therapies. Selective dorsal rhizotomy may have a place in the treatment of selected children with spastici...

Research paper thumbnail of A 14-Year-Old Female with Decreasing Visual Acuity, Severe Headache, Nausea and Vomiting

Pediatric Neurosurgery, Feb 1, 2001

Research paper thumbnail of Clinicopathological review: tumefactive demyelination in a 12-year-old girl

Neurosurgery, May 1, 2005

Dr. Anderson: The patient is a 12 year-old, right-handed girl without significant past medical or... more Dr. Anderson: The patient is a 12 year-old, right-handed girl without significant past medical or surgical history who developed the acute onset of right foot weakness approximately 10 days before admission. After sitting on the couch watching television, she tried to stand and ...

Research paper thumbnail of A new Hydrocephalus Clinical Research Network protocol to reduce cerebrospinal fluid shunt infection

Journal of neurosurgery. Pediatrics, Jan 18, 2015

OBJECT In a previous report by the same research group (Kestle et al., 2011), compliance with an ... more OBJECT In a previous report by the same research group (Kestle et al., 2011), compliance with an 11-step protocol was shown to reduce CSF shunt infection at Hydrocephalus Clinical Research Network (HCRN) centers (from 8.7% to 5.7%). Antibiotic-impregnated catheters (AICs) were not part of the protocol but were used off protocol by some surgeons. The authors therefore began using a new protocol that included AICs in an effort to reduce the infection rate further. METHODS The new protocol was implemented at HCRN centers on January 1, 2012, for all shunt procedures (excluding external ventricular drains [EVDs], ventricular reservoirs, and subgaleal shunts). Procedures performed up to September 30, 2013, were included (21 months). Compliance with the protocol and outcome events up to March 30, 2014, were recorded. The definition of infection was unchanged from the authors' previous report. RESULTS A total of 1935 procedures were performed on 1670 patients at 8 HCRN centers. The over...

Research paper thumbnail of Pediatric skull base surgery: 2. Experience and outcomes in 55 patients

Pediatric Neurosurgery, Feb 1, 2003

In the second of these two articles, we will discuss our clinical experience with skull base surg... more In the second of these two articles, we will discuss our clinical experience with skull base surgery in the pediatric population. We present a retrospective analysis of 55 patients less than 16 years of age who underwent skull base surgical approaches at the Primary Children's Medical Center or the University of Utah Medical Center between January 1992 and April 1999. There were 30 boys and 25 girls (mean age 9.8 years). Patient follow-up averaged 58 months. Most patients had pathology that required either an anterior or anterolateral approach; 6 patients underwent a far-lateral or a transpetrosal exposure. Thirty-five procedures were performed by a neurosurgeon, a pediatric otolaryngologist performed 11 procedures, and 10 procedures were performed by both services together. Ninety-six percent of patients (n = 53) had a Glasgow Outcome Score of 4 or 5. Complications included 4 sustained cranial nerve palsies and 2 hemipareses. There were no CSF leaks, infections or deaths. Patients with sellar region pathology had a disproportionately higher incidence of postoperative morbidity. We conclude that in selected pediatric cases, skull base surgical techniques can be performed effectively and safely with the use of multidisciplinary teams. To implement these techniques, knowledge of their limitations and of the anatomical differences between the adult and pediatric cranial base is essential.

Research paper thumbnail of Medical Management of Head Injuries in Neonates and Infants

Principles of Pediatric Neurosurgery, 1986

Research paper thumbnail of It's everything else you do...': Alumni views on extracurricular activities and employability

Active Learning in Higher Education, 2015

ABSTRACT This article explores students’ extracurricular activities and, uniquely, their short- a... more ABSTRACT This article explores students’ extracurricular activities and, uniquely, their short- and long-term effects on employability. Drawing on the literature, six research questions are identified. A questionnaire and interviews with alumni provide the quantitative and qualitative information needed. The effects of different extracurricular activities and the skills and qualities they promote are demonstrated for early- and later-career jobs, as are the complementary effects for employability of degree schemes and extracurricular activities. Alumni who are now recruiters of staff use their double perspective to explain the role extracurricular activities have played in their lives and now as professional recruiters. The paper shows how the alumni of any university could share these insights with undergraduates.

Research paper thumbnail of Poster 532 Validation of a Long-Term Post-Stroke Checklist

Research paper thumbnail of Stereotactic endoscopic placement of third ventricle catheter for long-term infusion of baclofen in patients with secondary generalized dystonia

Journal of neurosurgery. Pediatrics, 2012

Continuous infusion of baclofen is a treatment option for severe generalized dystonia. Catheter i... more Continuous infusion of baclofen is a treatment option for severe generalized dystonia. Catheter insertion within the third ventricle has been described as an alternative to standard intrathecal placement to maximize intracranial concentrations of baclofen. The authors describe their experience with a novel technique for stereotactic endoscopic insertion of baclofen infusion catheters in the third ventricle in 3 patients with severe secondary generalized dystonia. Insertion was successful in all 3 patients, and all of them experienced significant improvement in dystonia scores on the Barry-Albright Dystonia Scale. Follow-up ranged from 5.5 to 7 months (mean 6 months), and no mechanical complications or CSF leaks were observed. The stereotactic endoscopic insertion of a baclofen infusion catheter into the third ventricle appears to be a safe method for continuous intraventricular baclofen infusion in patients with generalized secondary dystonia.

Research paper thumbnail of Shunt failure due to intracranial migration of BioGlide ventricular catheters

Journal of neurosurgery. Pediatrics, 2011

In late 2008, the authors recognized a new type of ventriculoperitoneal shunt failure specific to... more In late 2008, the authors recognized a new type of ventriculoperitoneal shunt failure specific to the Bio-Glide Snap Shunt ventricular catheters. This prompted a retrospective review of the patient cohort and resulted in a recall by the FDA in the US. After the index cases were identified, the FDA was notified by the hospital, leading to a recall of the product. Hospital operative logs were used to identify patients in whom the affected products were used. A letter describing the risk was sent to all patients offering a free screening CT scan to look for disconnection. A call center was established to respond to patient questions, and an informational video was made available on the hospital website. The authors reviewed the records of the index cases and other cases subsequently identified. Seven index cases and an additional 16 cases of disconnection were identified in the 466 patients in whom a BioGlide Snap Shunt ventricular catheter had been implanted. Mean time to disconnectio...

Research paper thumbnail of The posterior petrosal approach: technique and applications in pediatric neurosurgery

Journal of neurosurgery. Pediatrics, 2009

Various lesions occur in deep locations or at the skull base in pediatric patients and require sk... more Various lesions occur in deep locations or at the skull base in pediatric patients and require skull base approaches for resection. Skull base surgery confers the advantages of improved line of sight, a wider operative corridor, and reduced brain retraction. The posterior petrosal approach provides simultaneous access to lesions in the posterior middle fossa and posterior fossa from the top of the clivus to the level of the jugular foramen. It allows visualization of the ventrolateral brainstem and may be combined with various other supra- and infratentorial approaches, thus giving the surgeon a wide array of access routes to the lesion. The authors conducted a retrospective review of all cases involving pediatric patients undergoing a posterior petrosal approach, either alone or in combination with other cranial approaches. Preoperative and postoperative data were collected, including presentation, neurological examination, imaging findings, pathological condition, operative detail...

Research paper thumbnail of Risk factors and rates of bone flap resorption in pediatric patients after decompressive craniectomy for traumatic brain injury

Journal of Neurosurgery: Pediatrics, 2013

Decompressive craniectomy with subsequent autologous cranioplasty, or the replacement of the nati... more Decompressive craniectomy with subsequent autologous cranioplasty, or the replacement of the native bone flap, is often used for pediatric patients with traumatic brain injury (TBI) who have a mass lesion and intractable intracranial hypertension. Bone flap resorption is common after bone flap replacement, necessitating additional surgery. The authors reviewed their large database of pediatric patients with TBI who underwent decompressive craniectomy followed by bone flap replacement to determine the rate of bone flap resorption and identify associated risk factors. A retrospective cohort chart review was performed to identify long-term survivors who underwent decompressive craniectomy for severe TBI with bone flap replacement from January 1, 1996, to December 31, 2011. The risk factors investigated in a univariate statistical analysis were age, sex, underlying parenchymal contusion, Glasgow Coma Scale score on arrival, comminuted skull fracture, posttraumatic hydrocephalus, bone flap wound infection, and freezer time (the amount of time the bone flap was stored in the freezer before replacement). A multivariate logistic regression model was then used to determine which of these were independent risk factors for bone flap resorption. Bone flap replacement was performed at an average of 2.1 months after decompressive craniectomy. Of the 54 patients identified (35 boys, 19 girls; mean age 6.2 years), 27 (50.0%) experienced bone flap resorption after an average of 4.8 months. Underlying parenchymal contusion, comminuted skull fracture, age ≤ 2.5 years, and posttraumatic hydrocephalus were significant, or nearly significant, on univariate analysis. Multivariate analysis identified underlying contusion (p = 0.004, OR 34.4, 95% CI 3.0-392.7), comminuted skull fractures (p = 0.046, OR 8.5, 95% CI 1.0-69.6), posttraumatic hydrocephalus (p = 0.005, OR 35.9, 95% CI 2.9-436.6), and age ≤ 2.5 years old (p = 0.01, OR 23.1, 95% CI 2.1-257.7) as independent risk factors for bone flap resorption. After decompressive craniectomy for pediatric TBI, half of the patients (50%) who underwent bone flap replacement experienced resorption. Multivariate analysis indicated young age (≤ 2.5 years), hydrocephalus, underlying contusion as opposed to a hemispheric acute subdural hematoma, and a comminuted skull fracture were all independent risk factors for bone flap resorption. Freezer time was not found to be associated with bone flap resorption.

Research paper thumbnail of Spinal arteriovenous fistulas in children with hereditary hemorrhagic telangiectasia

Journal of Neurosurgery: Pediatrics, 2012

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant angiodysplasia with high pen... more Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant angiodysplasia with high penetrance and variable expression. The manifestations of HHT are often age related, and spinal arteriovenous fistula (AVF) may be the initial presentation of HHT in young children. Because spinal AVFs are rarely reported, however, screening is not incorporated into current clinical recommendations for the treatment of patients with HHT. The authors describe 2 cases of children younger than 2 years of age with acute neurological deterioration in the context of a spinal AVF and in whom HHT was subsequently diagnosed. One patient presented with intraventricular and subarachnoid hemorrhage and the other with acute thrombosis of an intramedullary varix. These cases highlight the potential for significant neurological morbidity from a symptomatic AVF in very young children with HHT. Given the lack of data regarding the true incidence and natural history of these lesions, these cases raise the question of whether spinal cord imaging should be incorporated into screening recommendations for patients with HHT.

Research paper thumbnail of Factors associated with ventricular catheter movement and inaccurate catheter location: post hoc analysis of the Hydrocephalus Clinical Research Network Ultrasound-Guided Shunt Placement study

Journal of Neurosurgery: Pediatrics, 2014

Shunt survival may improve when ventricular catheters are placed into the frontal horn or trigone... more Shunt survival may improve when ventricular catheters are placed into the frontal horn or trigone of the lateral ventricle. However, techniques for accurate catheter placement have not been developed. The authors recently reported a prospective study designed to test the accuracy of catheter placement with the assistance of intraoperative ultrasound, but the results were poor (accurate placement in 59%). A major reason for the poor accurate placement rate was catheter movement that occurred between the time of the intraoperative ultrasound image and the first postoperative scan (33% of cases). The control group of non-ultrasound using surgeons also had a low rate of accurate placement (accurate placement in 49%). The authors conducted an exploratory post hoc analysis of patients in their ultrasound study to identify factors associated with either catheter movement or poor catheter placement so that improved surgical techniques for catheter insertion could be developed. The authors investigated the following risk factors for catheter movement and poor catheter placement: age, ventricular size, cortical mantle thickness, surgeon experience, surgeon experience with ultrasound prior to trial, shunt entry site, shunt hardware at entry site, ventricular catheter length, and use of an ultrasound probe guide for catheter insertion. Univariate analysis followed by multivariate logistic regression models were used to determine which factors were independent risk factors for either catheter movement or inaccurate catheter location. In the univariate analyses, only age < 6 months was associated with catheter movement (p = 0.021); cortical mantle thickness < 1 cm was near-significant (p = 0.066). In a multivariate model, age remained significant after adjusting for cortical mantle thickness (OR 8.35, exact 95% CI 1.20-infinity). Univariate analyses of factors associated with inaccurate catheter placement showed that age < 6 months (p = 0.001) and a posterior shunt entry site (p = 0.021) were both associated with poor catheter placement. In a multivariate model, both age < 6 months and a posterior shunt entry site were independent risk factors for…

Research paper thumbnail of Selective dorsal rhizotomy in children with spastic hemiparesis

Journal of Neurosurgery: Pediatrics, 2010

Neurological conditions including cerebral palsy, brain injury, and stroke often result in severe... more Neurological conditions including cerebral palsy, brain injury, and stroke often result in severe spasticity, which can lead to significant deformity and interfere with function. Treatments for spasticity include oral medications, intramuscular botulinum toxin type A injections, orthopedic surgeries, intrathecal baclofen pump implantation, and selective dorsal rhizotomy (SDR). Selective dorsal rhizotomy, which has been well studied in children with spastic diplegia, results in significant reduction in spasticity and improved function in children. To the authors' knowledge, there are no published outcome data for SDR in patients with spastic hemiparesis. The object of this study was to examine the effects of SDR on spastic hemiparesis. A 2-year study was undertaken including all children with spastic hemiparesis who underwent SDR at the authors' institution. The degree of spasticity, as measured by the Modified Ashworth Scale or quality of gait rated using the visual gait assessment scale, the gait parameters, and velocity were compared in patients before and after undergoing SDR. Thirteen children (mean age 6 years 7 months) with spastic hemiparesis underwent SDR performed by the same surgeon during a 2-year period. All of the patients had a decrease in tone in the affected lower extremity after the procedure. The mean reduction in tone in 4 muscle groups (hip adductors, knee flexors, knee extensors, and ankle plantar flexors) according to the modified Ashworth scale score was 2.6 ± 1.26 (p < 0.0001). The quality of gait was assessed in 7 patients by using the visual gait assessment scale. This score improved in 6 patients and remained the same in 1. Stride length and gait velocity were measured in 4 children. Velocity increased in 3 patients and decreased in a 3-year-old child. Parents and clinicians reported an improvement in quality of gait after the procedure. Stride length increased bilaterally in 3 patients and increased on one side and decreased on the other in the other patient. Selective dorsal rhizotomy showed efficacy in the treatment of spastic hemiparesis in children. All of the patients had decreased tone after SDR as measured by the modified Ashworth scale. The majority of patients had qualitative and quantitative improvements in gait.

Research paper thumbnail of A standardized protocol to reduce cerebrospinal fluid shunt infection: The Hydrocephalus Clinical Research Network Quality Improvement Initiative

Journal of Neurosurgery: Pediatrics, 2011

Research paper thumbnail of No significant improvement in the rate of accurate ventricular catheter location using ultrasound-guided CSF shunt insertion: a prospective, controlled study by the Hydrocephalus Clinical Research Network

Journal of Neurosurgery: Pediatrics, 2013

Cerebrospinal fluid shunt ventricular catheters inserted into the frontal horn or trigone are ass... more Cerebrospinal fluid shunt ventricular catheters inserted into the frontal horn or trigone are associated with prolonged shunt survival. Developing surgical techniques for accurate catheter insertion could, therefore, be beneficial to patients. This study was conducted to determine if the rate of accurate catheter location with intraoperative ultrasound guidance could exceed 80%. The authors conducted a prospective, multicenter study of children (< 18 years) requiring first-time treatment for hydrocephalus with a ventriculoperitoneal shunt. Using intraoperative ultrasound, surgeons were required to target the frontal horn or trigone for catheter tip placement. An intraoperative ultrasound image was obtained at the time of catheter insertion. Ventricular catheter location, the primary outcome measure, was determined from the first postoperative image. A control group of patients treated by nonultrasound surgeons (conventional surgeons) were enrolled using the same study criteria. Conventional shunt surgeons also agreed to target the frontal horn or trigone for all catheter insertions. Patients were triaged to participating surgeons based on call schedules at each center. A pediatric neuroradiologist blinded to method of insertion, center, and surgeon determined ventricular catheter tip location. Eleven surgeons enrolled as ultrasound surgeons and 6 as conventional surgeons. Between February 2009 and February 2010, 121 patients were enrolled at 4 Hydrocephalus Clinical Research Network centers. Experienced ultrasound surgeons (> 15 cases prior to study) operated on 67 patients; conventional surgeons operated on 52 patients. Experienced ultrasound surgeons achieved accurate catheter location in 39 (59%) of 66 patients, 95% CI (46%-71%). Intraoperative ultrasound images were compared with postoperative scans. In 32.7% of cases, the catheter tip moved from an accurate location on the intraoperative ultrasound image to an inaccurate location on the postoperative study. This was the most significant factor affecting accuracy. In comparison, conventional surgeons achieved accurate location in 24 (49.0%) of 49 cases (95% CI [34%-64%]). The shunt survival rate at 1 year was 70.8% in the experienced ultrasound group and 66.9% in the conventional group (p = 0.66). Ultrasound surgeons had more catheters surrounded by CSF (30.8% vs 6.1%, p = 0.0012) and away from the choroid plexus (72.3% vs 58.3%, p = 0.12), and fewer catheters in the brain (3% vs 22.4%, p = 0.0011) and crossing the midline (4.5% vs 34.7%, p < 0.001), but they had a higher proportion of postoperative pseudomeningocele (10.1% vs 3.8%, p = 0.30), wound dehiscence (5.8% vs 0%, p = 0.13), CSF leak (10.1% vs 1.9%, p = 0.14), and shunt infection (11.6% vs 5.8%, p = 0.35). Ultrasound-guided shunt insertion as performed in this study was unable to consistently place catheters into the frontal horn or trigone. The technique is safe and achieves outcomes similar to other conventional shunt insertion techniques. Further efforts to improve accurate catheter location should focus on prevention of catheter migration that occurs between intraoperative placement and postoperative imaging. Clinical trial registration no.: NCT01007786 ( ClinicalTrials.gov ).

Research paper thumbnail of Adjustment and malfunction of a programmable valve after exposure to toy magnets. Case report

Journal of neurosurgery, 2004

Inadvertent adjustments and malfunctions of programmable valves have been reported in cases in wh... more Inadvertent adjustments and malfunctions of programmable valves have been reported in cases in which patients have encountered powerful electromagnetic fields such as those involved in magnetic resonance imaging, but the effects of small magnetic fields are not well known. The authors present a case in which a child playing with a collection of commercially available toy magnets altered the pressure setting of an implanted valve and may have caused its permanent malfunction.

Research paper thumbnail of Complications of intracranial pressure monitoring in children with head trauma

Journal of neurosurgery, 2004

Intracranial pressure (ICP) monitoring has become routine in the management of patients with trau... more Intracranial pressure (ICP) monitoring has become routine in the management of patients with traumatic brain injury (TBI). Many surgeons prefer to use external ventricular drains (EVDs) over fiberoptic monitors to measure ICP because of the added benefit of cerebrospinal fluid drainage. The purpose of this study was to examine a consecutive series of children with TBI and compare the incidence of complications after placement of an EVD, a fiberoptic intraparencyhmal monitor, or both. A retrospective chart review was conducted to identify children with TBI who met the criteria for insertion of an ICP monitor. All patients underwent head CT scanning on admission and after placement of an ICP monitor. During a 5-year period 80 children met the criteria for inclusion in the study. Eighteen children (22.5%) underwent EVD placement only, 18 (22.5%) underwent placement of a fiberoptic device only, and 44 (55%) received both. A total of 62 fiberoptic devices (48%) were inserted, and 68 EVDs...