Cerebrospinal fluid shunt malfunctions: A reflective review.

PURPOSE: Pediatric hydrocephalus is a common and challenging condition. To date, the ventriculoperitoneal shunt (VPS) is still the main lifesaving treatment option. Nonetheless, it remains imperfect and is associated with multiple short- and long-term complications. This paper is a reflective review of the current state of the VPS, our knowledge gaps, and the future state of shunts in neurosurgical practice. METHODS AND RESULTS: The authors' reflections are based on a review of shunts and shunt-related literature. CONCLUSION: Overall, there is still an urgent need for the neurosurgical community to actively improve current strategies for shunt failures and shunt-related morbidity. The authors emphasize the role of collaborative efforts amongst like-minded clinicians to establish pragmatic approaches to avoid shunt complications.

Oberlin transfer and partial radial to axillary nerve neurotization to repair an explosive traumatic injury to the brachial plexus in a child: case report.

PURPOSE: Explosive injuries to the pediatric brachial plexus are exceedingly rare and as such are poorly characterized in the medical literature. METHODS: Herein, we describe an 8-year-old who was struck in the neck by a piece of shrapnel and suffered multiple vascular injuries in addition to a suspected avulsion of the cervical 5 and 6 ventral rami. The patient had a complete upper brachial plexus palsy and failed to demonstrate any clinical improvement at 6-months follow-up. He was taken to the operating from for a partial ulnar to musculocutaneous nerve neurotization as well as a partial radial to axillary nerve neurotization. RESULTS: The patient's motor exam improved from a Medical Research Council scale 1 to 4+ for biceps brachii and 0 to 4 deltoid function with greater than 90° of shoulder abduction. CONCLUSIONS: This outcome supports complex neurotization techniques as viable treatment options for persistent motor deficits following an upper brachial plexus injury in older, non-infant age, children.

Posterior plagiocephaly.

INTRODUCTION: Asymmetrical cranial vaults resulting from external forces on an infant's head can be caused by abnormal sutural development (synostotic plagiocephaly) or abnormal external forces acting on an intrinsically normal, developing cranium (deformational plagiocephaly). DISCUSSION: The incidence of posterior plagiocephaly has increased dramatically since the initiation of the "Back to Sleep" campaign against sudden infant death syndrome. The majority of cases are due to deformational plagiocephaly, but rigorous diagnostic evaluation including physical examination and radiological imaging must be undertaken to rule out lambdoid synostosis in extreme or refractory cases. CONCLUSION: Unique clinical features and radiological examination using computed tomography technology are helpful in confirming the correct cause of posterior plagiocephaly. Plagiocephaly is considered a benign condition, but with the recent increase in cases, new studies have revealed developmental problems associated with cranial vault asymmetries. Treatment of positional/deformational plagiocephaly includes conservative measures, primarily behavior modification, and, in some cases, helmet therapy, whereas lambdoid synostotic plagiocephaly requires surgical intervention, making differentiation of the cause of the asymmetry critical.

Thoracolumbar Injury Classification and Severity Score in Children: A Validity Study.

BACKGROUND: The Thoracolumbar Injury Classification and Severity Score (TLICS) has been shown to be a valid tool for assessing the need for surgical intervention in adult patients. There is limited insight into its usefulness in children. OBJECTIVE: To assess the validity of the TLICS system in pediatric patients. METHODS: The medical records for pediatric patients with acute, traumatic thoracolumbar fractures at two Level 1 trauma centers were reviewed retrospectively. A TLICS score was calculated for each patient using computed tomography and magnetic resonance images, along with the neurological examination recorded in the patient's medical record. TLICS scores were compared with the type of treatment received. Receiver operating characteristic (ROC) curve analysis was employed to quantify the validity of the TLICS scoring system. RESULTS: TLICS calculations were completed for 165 patients. The mean TLICS score was 2.9 (standard deviation ± 2.7). Surgery was the treatment of choice for 23% of patients. There was statistically significant agreement between the TLICS suggested treatment and the actual treatment received (P < 0.001). The ROC curve calculated using multivariate logistic regression analysis of the TLICS system's parameters as a tool for predicting treatment demonstrated excellent discriminative ability, with an area under the ROC curve of 0.96, which was also statistically significant (P < 0.001). CONCLUSION: The TLICS system demonstrates good validity for selecting appropriate thoracolumbar fracture treatment in pediatric patients.

Predicting slitlike ventricles in children on the basis of baseline characteristics at the time of shunt insertion.

OBJECT: Slit ventricle syndrome (SVS) is a delayed complication of shunt insertion and occurs only in children with slitlike ventricles after shunt placement. Although SVS appears to be related to early shunt placement, its predisposing factors are largely unknown. METHODS: Baseline data in 737 children who had received shunts were obtained from the databases of two previous clinical trials. Ventricular size before shunt placement and at the last routine follow up was measured using the frontooccipital horn ratio (FOHR). Ventricles with an FOHR less than or equal to 0.2 at follow up were classified as slitlike ventricles. A univariate analysis was performed on data obtained in children with more than 1 year of clinical and radiographic follow up to identify risk factors for developing slitlike ventricles. These results were entered into a multivariate analysis to identify independent predictors of slitlike ventricles. Two hundred forty-four children had more than 1 year of clinical and radiographic follow-up data. The 23 patients (9.4%) who developed slitlike ventricles had shunts inserted at a younger age (42 compared with 134 days, p = 0.09) and were more likely to have developed hydrocephalus secondary to infection (37.5%), head injury (25.0%), or aqueductal stenosis (22.2%). Slitlike ventricles were seen in 10.8% of patients with differential-pressure valves, 10.5% of patients with Delta valves, and 3.6% of patients with Orbis-Sigma valves (p = 0.007). Regression analysis supported the role of the valve type in developing slitlike ventricles. CONCLUSIONS: Age at shunt insertion and valve type appear to be the modifiable risk factors for developing slitlike ventricles. If the authors of subsequent studies can further validate these conclusions, slow-draining valves and delayed shunt insertion might be used to decrease the incidence of slitlike ventricles and SVS.

Evaluation of the necessity of postoperative imaging after craniosynostosis surgery.

OBJECT: Childhood radiation exposure increases the lifetime risk of cancer from an estimated 0.07 to 0.35%. Neurological evaluation of patients after cranial vault reconstruction for synostosis repair is often complicated by pain medication, sedation, intubation, swelling, and dressings; therefore computed tomography (CT) scans are routinely ordered by some surgeons on the 1st postoperative day. The object of this study was to evaluate the utility of these scans. METHODS: Medical records and CT scans were reviewed for patients at the authors' institution who underwent cranial vault reconstruction to repair synostosis between January 1, 2003, and July 31, 2005. RESULTS: Of the 111 patients identified in the review, 84 had a CT scan on postoperative Day 1, and seven of these patients underwent shunt insertion for treatment of hydrocephalus. Thirty-three patients underwent bifrontal craniotomies, whereas 51 underwent total vault reconstruction (TVR). Postoperative CT scans revealed minor contusions in three (9%) of 33 patients in the bifrontal craniotomy group and in seven (14%) of 51 patients in the TVR group. No significant subdural or epidural hematomas were observed. In the seven patients who required shunt placement, two (29%) had CT evidence of shunt malfunction, leading to shunt revision. CONCLUSIONS: None of the CT findings analyzed in this series was associated with clinical events such as seizures, prolonged intensive care unit stay, or reoperation in patients without shunt placement after cranial reconstructive procedures, although a relatively high incidence of CT evidence of shunt malfunction was found in patients with shunts. These data do not support the routine use of CT scanning after cranial reconstructive procedures unless the patient has received a shunt for hydrocephalus. Patients who experience unexpected intraoperative or postoperative events should be examined using CT.

Real-time image-guided direct convective perfusion of intrinsic brainstem lesions. Technical note.

Recent preclinical studies have demonstrated that convection-enhanced delivery (CED) can be used to perfuse the brain and brainstem with therapeutic agents while simultaneously tracking their distribution using coinfusion of a surrogate magnetic resonance (MR) imaging tracer. The authors describe a technique for the successful clinical application of this drug delivery and monitoring paradigm to the brainstem. Two patients with progressive intrinsic brainstem lesions (one with Type 2 Gaucher disease and one with a diffuse pontine glioma) were treated with CED of putative therapeutic agents mixed with Gd-diethylenetriamene pentaacetic acid (DTPA). Both patients underwent frameless stereotactic placement of MR imaging-compatible outer guide-inner infusion cannulae. Using intraoperative MR imaging, accurate cannula placement was confirmed and real-time imaging during infusion clearly demonstrated progressive filling of the targeted region with the drug and Gd-DTPA infusate. Neither patient had clinical or imaging evidence of short- or long-term infusate-related toxicity. Using this technique, CED can be used to safely perfuse targeted regions of diseased brainstem with therapeutic agents. Coinfused imaging surrogate tracers can be used to monitor and control the distribution of therapeutic agents in vivo. Patients with a variety of intrinsic brainstem and other central nervous system disorders may benefit from a similar treatment paradigm.

Priorities for hydrocephalus research: report from a National Institutes of Health-sponsored workshop.

OBJECT: Treatment for hydrocephalus has not advanced appreciably since the advent of cerebrospinal fluid (CSF) shunts more than 50 years ago. Many questions remain that clinical and basic research could address, which in turn could improve therapeutic options. To clarify the main issues facing hydrocephalus research and to identify critical advances necessary to improve outcomes for patients with hydrocephalus, the National Institutes of Health (NIH) sponsored a workshop titled "Hydrocephalus: Myths, New Facts, and Clear Directions." The purpose of this paper is to report on the recommendations that resulted from that workshop. METHODS: The workshop convened from September 29 to October 1, 2005, in Bethesda, Maryland. Among the 150 attendees was an international group of participants, including experts in pediatric and adult hydrocephalus as well as scientists working in related fields, neurosurgeons, laboratory-based neuroscientists, neurologists, patient advocates, individuals with hydrocephalus, parents, and NIH program and intramural staff. Plenary and breakout sessions covered injury and recovery mechanisms, modeling, biomechanics, diagnosis, current treatment and outcomes, complications, quality of life, future treatments, medical devices, development of research networks and information sharing, and education and career development. RESULTS: The conclusions were as follows: 1) current methods of diagnosis, treatment, and outcomes monitoring need improvement; 2) frequent complications, poor rate of shunt survival, and poor quality of life for patients lead to unsatisfactory outcomes; 3) investigators and caregivers need additional methods to monitor neurocognitive function and control of CSF variables such as pressure, flow, or pulsatility; 4) research warrants novel interdisciplinary approaches; 5) understanding of the pathophysiological and recovery mechanisms of neuronal function in hydrocephalus is poor, warranting further investigation; and 6) both basic and clinical aspects warrant expanded and innovative training programs. CONCLUSIONS: The research priorities of this workshop provide critical guidance for future research in hydrocephalus, which should result in advances in knowledge, and ultimately in the treatment for this important disorder and improved outcomes in patients of all ages.

Spinal lipomas: clinical spectrum, embryology, and treatment.

Spinal lipomas, particularly lipomas of the conus medullaris and terminal filum, are the most common form of occult spinal dysraphism and represent a wide spectrum of disease with regard to anatomy, clinical presentation, and treatment options. These lesions, however, are united by a similar embryology and pathological mechanism by which symptoms arise. Recently, the treatment of these lesions has generated much controversy, with some physicians advocating surgical treatment for all patients regardless of symptoms and others proposing that surgery be withheld until symptoms develop. The authors discuss lumbosacral spinal lipomas, with particular attention to the theories of their origin, anatomical and pathological features, and treatment options, including a review of current controversies.

Effects of congenital hydrocephalus on the hypothalamic gonadotrophin-releasing hormone system.

OBJECT: Despite the investigations that have linked hydrocephalus to reproductive system abnormalities, no researchers have attempted to identify the pathophysiological mechanism of this relationship. Because the role of the hypothalamic gonadotrophin-releasing hormone (GnRH) system in the regulation of reproductive functions is well established, the authors used immunohistochemical and radioimmunoassay (RIA) techniques to determine the morphological and biochemical effects of hydrocephalus on the hypothalamic GnRH system. METHODS: Hypothalamic GnRH levels, fiber density, and cell types were studied in 21- and 50-day-old control and congenitally hydrocephalic Texas rats. Results of RIA indicated a significant (8.4%) increase in GnRH in 21-day-old hydrocephalic rats (9.17 +/- 0.64 pg/ng total protein) compared with that in controls (0.97 +/- 0.74 pg/ng total protein). In addition, the 50-day-old hydrocephalic animals had a significantly higher level of GnRH compared with age-matched controls (20.4 pg/ng compared with 1.88 +/- 2.1 pg/ng total protein). This increase was accompanied by changes in the fiber appearance and a shift from low GnRH producing cells to high GnRH producing cells in the hydrocephalic animals; however, there was no significant difference in the fiber density between the control and hydrocephalic animals at 21 days. In addition, poor neurological scores correlated with the severity of hydrocephalus. CONCLUSIONS: These results demonstrated that hypothalamic GnRH levels are significantly affected by fetal-onset hydrocephalus and that the mechanisms responsible for these effects may take place at the cellular rather than the gross structural level. Furthermore, they suggest that impairments in the GnRH system may be protracted in neonates and infants with hydrocephalus, and thus may be overcome by relatively early treatment with ventricular diversion. However, the clinical implications of GnRH perturbations in shunt-dependent patients must await a forthcoming study in shunted animals.

Optic pathway gliomas: a review.

Optic pathway gliomas represent approximately 3-5% of childhood intracranial tumors. They usually occur in children during the first decade of life and are seen in 11-30% of patients with neurofibromatosis Type 1 (NF1). Although these tumors are typically low-grade gliomas, the clinical course and natural history are highly variable, making treatment paradigms difficult. Overall, however, they are often indolent tumors that can be observed over time for progression without initial treatment, especially in patients with NF1. Chemotherapy is the first-line treatment for progressive tumors, and radiation therapy is reserved for patients with progressive disease who are older than 5-7 years. Surgery is reserved for large tumors causing mass effect or hydrocephalus and tumors confined to the orbit or unilateral optic nerve.

Risk factors for progressive neuromuscular scoliosis requiring posterior spinal fusion after selective dorsal rhizotomy.

OBJECTIVE Selective dorsal rhizotomy (SDR) via limited laminectomy is an effective treatment of lower-extremity spasticity in the pediatric population. Children with spasticity are also at risk for neuromuscular scoliosis; however, specific risk factors for progressive spinal deformity requiring posterior spinal fusion (PSF) after SDR are unknown. The authors' goal was to identify potential risk factors. METHODS The authors performed a retrospective cohort study of patients who underwent SDR via limited laminectomy between 2003 and 2014 and who had at least 1 year of follow-up. They analyzed demographic, clinical, and radiographic variables to elucidate risk factors for progressive neuromuscular scoliosis. The primary outcome was need for PSF. RESULTS One hundred thirty-four patients underwent SDR and had at least 12 months of follow-up (mean 65 months); 48 patients (36%) had detailed pre- and postoperative radiographic data available. The mean age at surgery was 10 years (SD 5.1 years). Eighty-four patients (63%) were ambulatory before SDR, 109 (82%) underwent a single-level laminectomy, and a mean of 53% of the dorsal rootlets from L-1 to S-1 were sectioned. Fifteen patients (11.2%) subsequently required PSF for progressive deformity. Nonambulatory status (p < 0.001) and a preoperative Cobb angle > 30° (p = 0.003) were significantly associated with PSF on univariate analysis, but no statistically significant correlation was found with any clinical or radiographic variable and PSF after SDR on multivariate regression analysis. CONCLUSIONS Patients with preoperative nonambulatory status and Cobb angle > 30° may be at risk for progressive spinal deformity requiring PSF after SDR. These are well-known risk factors for progressive deformity in children with spasticity in general. Although our analysis suggests SDR via limited laminectomy may not significantly accelerate the development of neuromuscular scoliosis, further case-control studies are critical to elucidate the impact of SDR on spinal deformity.

Outcomes after decompressive craniectomy for severe traumatic brain injury in children.

OBJECT: Severe traumatic brain injury (TBI) is often accompanied by early death due to transtentorial herniation. Decompressive craniectomy, performed alone or in conjunction with evacuation of the mass lesion, can reduce the incidence of raised intracranial pressure (ICP). In this paper the authors evaluate mortality and morbidity and long-term outcomes in children who underwent decompressive craniectomy for severe TBI at a single institution. METHODS: Children with severe TBI who underwent decompressive craniectomy at the Primary Children's Medical Center between 1996 and 2005 were identified retrospectively. Descriptive statistics were used to report postoperative mortality and morbidity rates. Long-term recovery in patients who survived was reported using the King's Outcome Scale for Closed Head Injury (KOSCHI). Fifty-one children with a mean follow-up period of 18.6 months were identified. Nonaccidental trauma accounted for 23.5% of cases. The mean preoperative Glasgow Coma Scale (GCS) score was 4.6. Six patients underwent decompressive craniectomy for elevated ICP only; all other patients underwent decompressive craniectomy in conjunction with removal of the mass lesion. The mean postoperative GCS score was 9.7, and 69.4% of patients had normal ICP levels immediately after surgery. Sixteen children (31.4%) died, including five of six children who underwent decompressive craniectomy for raised ICP alone. Among surviving patients, 2.9% required a tracheostomy, 11.4% required a gastrostomy, 40% experienced posttraumatic shunt-dependent hydrocephalus, and 20% suffered posttraumatic epilepsy requiring antiepileptic agents. The mean KOSCHI score at the last follow-up examination was 4.5 and the mean time to cranioplasty was 2.3 months. CONCLUSIONS: Posttraumatic hydrocephalus and epilepsy were common complications encountered by children with severe TBI who underwent decompressive craniectomy. In patients who underwent decompressive surgery for raised ICP only, the mortality rate was exceedingly high.

Management of shunt infections: a multicenter pilot study.

OBJECT: Approximately 10% of cerebrospinal fluid (CSF) shunt operations are associated with infection and require removal or externalization of the shunt, in-hospital treatment with antibiotic agents, and insertion of a new shunt. In a previous survey, the authors identified substantial variation in the duration of antibiotic therapy as well as the duration of hospital stay. The present multicenter pilot study was undertaken to evaluate current strategies in the treatment of shunt infection. METHODS: Patients were enrolled in the study if they had a successful treatment of a CSF shunt infection proved by culture of a CSF specimen. Details of their care and the incidence of culture-proved reinfection were recorded. Seventy patients from 10 centers were followed up for 1 year after their CSF shunt infection. The initial management of the infection was shunt externalization in 17 patients, shunt removal and external ventricular drain insertion in 50, and antibiotic treatment alone in three. Reinfection occurred in 18 patients (26%). Twelve of the 18 reinfections were caused by the same organism and six were due to new organisms. The treatment time varied from 4 to 47 days, with a mean of 17.4 days for those who later experienced a reinfection compared with 16.2 days for those who did not. The most common organism (Staphylococcus epidermidis, 34 patients) was associated with a reinfection rate of 29% and a mean treatment time of 12.8 days for those who suffered reinfection and 12.5 days for those who did not. CONCLUSIONS: Reinfection after treatment of a CSF shunt infection is alarmingly common. According to the data available, the incidence of reinfection does not appear to be related to the duration of antibiotic therapy.

What we don't (but should) know about hydrocephalus.

In an effort to identify critical gaps in the prevailing knowledge of hydrocephalus, the authors formulated 10 key questions. 1) How do we define hydrocephalus? 2) How is cerebrosinal fluid (CSF) absorbed normally and what are the causes of CSF malabsorption in hydrocephalus? 3) Why do the ventricles dilate in communicating hydrocephalus? 4) What happens to the structure and function of the brain when it is compressed and stretched by the expanding ventricles? 5) What is the role of cerebrovenous pressure in hydrocephalus? 6) What causes normal-pressure hydrocephalus? 7) What causes low-pressure hydrocephalus? 8) What is the pathophysiology of slit ventricle syndrome? 9) What is the pathophysiological basis for neurological impairment in hydrocephalus, and to what extent is it reversible? 10) How is the brain of a child with hydrocephalus different from that of a young or elderly adult? Rigorous answers to these questions should lead to more effective and reliable treatments for this disorder.

A new Hydrocephalus Clinical Research Network protocol to reduce cerebrospinal fluid shunt infection.

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 overall infection rate was 6.0% (95% CI 5.1%-7.2%). Procedure-specific infection rates varied (insertion 5.0%, revision 5.4%, insertion after EVD 8.3%, and insertion after treatment of infection 12.6%). Full compliance with the protocol occurred in 77% of procedures. The infection rate was 5.0% after compliant procedures and 8.7% after noncompliant procedures (p = 0.005). The infection rate when using this new protocol (6.0%, 95% CI 5.1%-7.2%) was similar to the infection rate observed using the authors' old protocol (5.7%, 95% CI 4.6%-7.0%). CONCLUSIONS CSF shunt procedures performed in compliance with a new infection prevention protocol at HCRN centers had a lower infection rate than noncompliant procedures. Implementation of the new protocol (including AICs) was associated with a 6.0% infection rate, similar to the infection rate of 5.7% from the authors' previously reported protocol. Based on the current data, the role of AICs compared with other infection prevention measures is unclear.

Posterior cervical approach for intrathecal baclofen pump insertion in children with previous spinal fusions. Technical note.

Intrathecal baclofen pumps for the management of severe spasticity are being used more often in children with cerebral palsy. The intrathecal catheter is traditionally introduced dorsally in the lumbar region. In some children with previous thoracolumbar fusions for scoliosis, the fusion mass obviates the introduction of the intrathecal catheter. The authors describe their experience with a posterior cervical approach for intrathecal baclofen pump insertion in three patients with spastic quadriplegic cerebral palsy who had previously undergone thoracolumbar fusions for scoliosis. Insertion was successful in all three patients; no complications of catheter disconnection, catheter dislodgment, or cerebrospinal fluid leakage occurred. Follow-up review ranged from 10 to 28 months postoperatively (mean 17 months). The posterior cervical approach for intrathecal baclofen pump insertion is a safe and effective alternative for patients who have previously undergone thoracolumbar spine fusions and in whom the traditional lumbar approach is not feasible.

A multicenter prospective cohort study of the Strata valve for the management of hydrocephalus in pediatric patients.

OBJECT: Previous reports suggest that adjustable valves may improve the survival of cerebrospinal fluid shunts or relieve shunt-related symptoms. To evaluate these claims, the authors conducted a prospective multicenter cohort study of children who underwent placement of Strata valves. METHODS: Patients undergoing initial shunt placement (Group 1) or shunt revision (Group 2) were treated using Strata valve shunt systems. Valves were adjustable to five performance level settings by using an externally applied magnet. The performance levels were checked using an externally applied hand tool and radiography. Patients were followed for 1 year or until they underwent shunt revision surgery. Between March 2000 and February 2002, 315 patients were enrolled in the study. In Group 1 (201 patients) the common causes of hydrocephalus were myelomeningocele (16%), aqueductal stenosis (14%), and hemorrhage (14%). The overall 1-year shunt survival was 67%. Causes of shunt failure were obstruction (17%), overdrainage (1.5%), loculated ventricles (2%), and infection (10.6%). Patients in Group 2 (114 patients) were older and the causes of hydrocephalus were similar. Among patients in Group 2 the 1-year shunt survival was 71%. There were 256 valve adjustments. Symptoms completely resolved (26%) or improved (37%) after 63% of adjustments. When symptoms improved or resolved, they did so within 24 hours in 89% of adjustments. Hand-tool and radiographic readings of valve settings were the same in 234 (98%) of 238 assessments. CONCLUSIONS: The 1-year shunt survival for the Strata valve shunt system when used in initial shunt insertion procedures or shunt revisions was similar to those demonstrated for other valves. Symptom relief or improvement following adjustment was observed in 63% of patients. Hand-tool assessment of performance level settings reliably predicted radiographic assessments.