Frontal Shunt Research Articles

Risk factors for unchanged ventricles during pediatric shunt malfunction.

Children whose ventricles do not change during shunt malfunction present a diagnostic dilemma. This study was performed to identify risk factors for unchanged ventricular size at shunt malfunction. This retrospective 1:1 age-matched case-control study identified children with shunted hydrocephalus who underwent shunt revision with intraoperative evidence of malfunction at one of the three participating institutions from 1997 to 2019. Cases were defined as patients with a change of < 0.05 in the frontal-occipital horn ratio (FOR) between malfunction and baseline, and controls included patients with FOR changes ≥ 0.05. The presence of infection, abdominal pseudocyst, pseudomeningocele, or wound drainage and lack of baseline cranial imaging at the time of malfunction warranted exclusion. Of 450 included patients, 60% were male, 73% were Caucasian, and 67% had an occipital shunt. The median age was 4.3 (IQR 0.97-9.21) years at malfunction. On univariable analysis, unchanged ventricles at malfunction were associated with a frontal shunt (41% vs 28%, p < 0.001), programmable valve (17% vs 9%, p = 0.011), nonsiphoning shunt (85% vs 66%, p < 0.001), larger baseline FOR (0.44 ± 0.12 vs 0.38 ± 0.11, p < 0.001), no prior shunt infection (87% vs 76%, p = 0.003), and no prior shunt revisions (68% vs 52%, p < 0.001). On multivariable analysis with collinear variables removed, patients with a frontal shunt (OR 1.67, 95% CI 1.08-2.70, p = 0.037), programmable valve (OR 2.63, 95% CI 1.32-5.26, p = 0.007), nonsiphoning shunt at malfunction (OR 2.76, 95% CI 1.63-4.67, p < 0.001), larger baseline FOR (OR 3.13, 95% CI 2.21-4.43, p < 0.001), and no prior shunt infection (OR 2.34, 95% CI 1.27-4.30, p = 0.007) were more likely to have unchanged ventricles at malfunction. In a multicenter cohort of children with shunt malfunction, those with a frontal shunt, programmable valve, nonsiphoning shunt, baseline large ventricles, and no prior shunt infection were more likely than others to have unchanged ventricles at shunt failure.

A CASE OF OSA IN A PATIENT WITH A VENTRICULO-PERITONEAL SHUNT: A REAL HEADACHE

SESSION TITLE: Medical Student/Resident Sleep Disorders Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: The patient is a 65 year old female who presented to the pulmonology clinic for management of her Obstuctive Sleep Apnea Syndrome (OSAS). She had been diagnosed with OSAS in early 2017 after a sleep study at an external facility and had been prescribed a Continuous Positive Airway Pressure (CPAP) Machine fitted with an oro-nasal mask. She had not been able to use the CPAP due to recurrent headaches and nasal congestion associated with use. CASE PRESENTATION: The patient was diagnosed with pseudotumo- cerebri after a motor vehicle accident in 2004. A right-sided ventricular shunt catheter (VP shunt) was placed in 2005. Her nausea, dizziness and frequent headaches subsequently resolved. In the interim she had been following up with her neurosurgeon and primary care physician on a regular basis and remained symptom free. She had a past medical history of mild intermittent asthma, pulmonary artery hypertension and hypertension which were well controlled with medical management. Five months after starting to use the CPAP machine she presented to her neurosurgeon with symptoms of dizziness, headaches and gait instability. Visit records were obtained with the patients consent and it was noted the neurological exam at the time was unremarkable and opthalmoscopic inspection did not show any evidence of papilledema. The Ventriculo-Peritoneal (VP) shunt was interrogated at the time and found to be functioning optimally. She was referred for a Computed Tomography (CT) scan of the head and a shunt study. CT head after showed the right frontal shunt catheter in position with a decrease in volume of the right lateral ventricle, there was no evidence of hemorrhage, hydrocephalus or extra-axial fluid. The shunt study showed no evidence of kinking or obstruction in the catheter along its course from the right lateral aspect of the cranium, over the right neck and right hemithorax up to the left abdomen overlying the left sacroiliac joint. The concurrent initiation of her symptoms with starting CPAP machine use warranted enquiry. The patient visited the pulmonology clinic 4 months later. In the interim she had stopped using the CPAP machine and her headaches, dizziness and gait instability had resolved, albeit her OSAS was uncontrolled. DISCUSSION: In view of the unremarkable CT of the head and normal shunt study the patients symptoms were attributed to external compression of the VP shunt by the securing straps of the oro-nasal attachment for the CPAP machine. This periodic occlusion could lead to an intermittent intracranial hypertension, which manifests as dizziness and gait instability with headaches. The intermittent nature of the obstruction resulted in the absence of ventriculomegaly on CT and the normal shunt study. CONCLUSIONS: The patient was fitted with a Dental appliance(Mandibular advancement device/ tongue retaining mouthpiece) for management of her OSAS and her symptoms resolved. Reference #1: Chee, B. N. H., Jalil, M. F. A., & Bulluss, K. J. (2016). Spontaneous pneumocephalus from nasal continuous positive airway pressure in a patient with ventriculo-peritoneal shunt. Journal of Clinical Neuroscience, 34, 215–217. doi: 10.1016/j.jocn.2016.05.040 Reference #2: Salem-Memou, S., Vallee, B., Jacquesson, T., Jouanneau, E., & Berhouma, M. (2016). Pathogenesis of Delayed Tension Intraventricular Pneumocephalus in Shunted Patient: Possible Role of Nocturnal Positive Pressure Ventilation. World Neurosurgery, 85. doi: 10.1016/j.wneu.2015.09.001 Reference #3: Jones, R., Davis, E. M., & Coleman, J. (2016). Pneumocephalus Secondary to CPAP in Setting of Remote Craniofacial Trauma. Chest, 150(4). doi: 10.1016/j.chest.2016.08.276 DISCLOSURES: No relevant relationships by Matthew Castillo, source=Web Response No relevant relationships by Abhishek Chakraborti, source=Web Response No relevant relationships by Erum Zahid, source=Web Response

Strengths and weaknesses of frontal versus occipital ventriculoperitoneal shunt placement: A systematic review

Excessive accumulation of cerebrospinal fluid within the brain ventricles is called hydrocephalus, which results in increased intracranial pressure preventing brain growth or causing damage to intracranial structures due to raised intracranial pressure. One of the most common treatment options for this pathology includes the placement of a ventriculoperitoneal shunt to drain the excess fluid. The location of catheterization is traditionally considered as an important factor affecting shunt survival. In this study, we aimed to systematically review all available documents to determine the advantage and superiority of frontal or occipital shunt entry points as the two main approaches. A database search was performed in PubMed, Scopus, Embase, Web of Science, Medline, Ovid, and Google Scholar using "ventriculoperitoneal", "shunt placement", and "hydrocephalus" as the main key terms. Resultant articles were screened for relevancy based on predefined inclusion and exclusion criteria by two authors independently. After excluding irrelevant documents, the data of 11 related articles consisting of 3947 patients were extracted and qualitative data synthesis and pooled analysis were performed. The results of the included studies showed that although the outcomes of a higher percentage of the total review population were in favor of frontal shunt placement, there was no significant superiority for neither of these two approaches after pooled analysis of available failure rates. Findings have shown that each approach has benefits and drawbacks, and there may be other factors such as age and valve design besides the position of shunt placement that may affect the survival rate. Also, the accuracy of shunt placement as an independent factor affects the failure rate and can be improved with various image-guidance methods to minimize shunt failure.

Approach to Slitlike Ventricles: Parietal-Occipital versus Frontal Burr Catheter Entry Sites

Slit ventricles can be a challenging target during shunt catheter insertion. Traditionally, the frontal approach has been considered optimal for small ventricles. At this center, routine use of electromagnetic (EM) stereotactic guidance (Stealth, Medtronic, Dublin, Ireland) has enabled a parietooccipital (P-O) burr hole approach to the frontal horns. We compare shunt placement and revisions required for patients with slit ventricles who had shunts inserted via a P-O approach versus frontal shunt. We studied a retrospective cohort of patients with slit ventricles and a ventricular shunt inserted using EM guidance between 2012 and 2018. Slitlike ventricles were defined as the widest point of the lateral ventricle <3 mm. Outcome measures included placement accuracy and survival using the Kaplan-Meier curve. Optimal final catheter tip location was considered to be the frontal horn of the ipsilateral lateral ventricle. Eighty-two patients (77 female, 5 male) aged 34.9 ± 10.8 years (mean ± standard deviation) had ventricular shunts inserted for idiopathic intracranial hypertension (n= 63), chiari/syrinx (n= 8), congenital (n= 10), and pseudomeningocele (n= 1). Of those identified, 35 had primary P-O shunts and 46 had frontal shunts. Overall, 94% of cases had the catheter tip sitting in the frontal horn. The P-O approach was just as accurate as the frontal approach. Eight P-O shunts and 9 frontal shunts required revision over a 60-month period. There was no significant different in shunt survival between the 2 approaches (P= 0.37). EM-guided placement has enabled the P-O approach to be as safe and with equivalent survival to frontal approach. The accuracy of shunt placement between the 2 approaches was similar.

P102 Shunting slit ventricles: a comparison of the parieto-occipital vs frontal approach

ObjectivesSlit ventricles can be a challenging target during shunt catheter insertion. Traditionally, the frontal approach has been considered optimal. At this centre, routine use of electromagnetic (EM) stereotatic guidance (StealthTM, Medtronic) has enabled a parieto-occipital burr hole approach to the frontal horns. We compare shunt placement and revisions required for patients with slit ventricles who had shunts inserted via a parieto-occipital (P-O) approach vs. frontal shunt.DesignRetrospective cohort.SubjectsPatients with slit ventricles and a ventricular shunt inserted using EM guidance between 2012–2018.MethodsSlit ventricles were defined as &lt;3 mm (widest). Outcome measures included placement accuary and survival using Kaplan-Meier curve.Results82 patients (77F:5M) aged 34.9±10.8 years (mean ±SD) had shunts inserted for IIH (n=63), chiari/syrinx (n=8), congenital hydrocephalus (n=10), pseudomeningocoele (n=1). 35 had primary P-O shunts and 46 had frontal shunts. Overall, 94% of cases had the catheter tip sitting in the frontal horn. The P-O approach was just as accurate as the frontal approach. Eight P-O shunts and 9 frontal shunts required revision over a 60 month periods. There was no significant different in shunt survival between the two approaches (p=0.99).ConclusionsEM guided placement has enabled the P-O approach to be as safe and with equivalent survival to frontal approach. The accuracy of shunt placement between the two approaches was equivocal.

Ventricular catheter placement accuracy in non-stereotactic shunt surgery for hydrocephalus

We aimed to compare the accuracy of different shunt catheter approaches to the lateral ventricle in adults with hydrocephalus. We conducted a retrospective review of 138 consecutive patients with hydrocephalus undergoing freehand initial shunt surgery. Of these, 79 had a post-operative brain scan and therefore the results were available for analysis. Scans were graded for successful catheter tip placement in the ventricular target zones: the frontal horn for frontal and occipital approaches, and the atrium for the parietal approach. Ventricular target zones were successfully catheterized in 85% of parietal and 64% of frontal shunts (this difference is not statistically significant). In contrast, only 42% of occipital shunts were correctly placed ( p < 0.01). Therefore, parietal and frontal catheters are more likely to be placed successfully in the target ventricle. This may be due to the smaller range of successful trajectories open to the occipital approach. Solutions to this problem may include using the theoretically favourable frontal approach for freehand surgery or using stereotactic guidance.

Failure rate of frontal versus parietal approaches for proximal catheter placement in ventriculoperitoneal shunts: revisited

Early studies on ventriculoperitoneal shunt malfunctions demonstrated that proximal catheter obstruction was the most common cause for shunt malfunction and choroid plexus was the primary culprit for catheter obstruction. Subsequently, several studies were performed using stereotactic and endoscopic guidance systems to assist with optimal placement of proximal shunt catheters. Surgeons collectively agree that optimum placement of the proximal catheter tip is away from choroid plexus in the frontal horn. To achieve this catheter placement, neurosurgeons typically choose a frontal or parietal approach. Two previous studies comparing parietal and frontal shunt failure rates in the pediatric population have different conclusions. Thus, we decided to compare proximal catheter failure rates of frontal versus parietal approaches on 117 patients (ages ranging from 1 month to 80 years) who had undergone ventriculoperitoneal shunt placement at our institution. Statistical analysis demonstrated a significantly higher malfunction rate in the patients less than 3 years of age and a lower overall malfunction rate in patients shunted for normal pressure hydrocephalus. Surprisingly, there was no significant difference between the two surgical approaches. Thus, we concluded after reviewing the literature, that regardless of the initial surgical approach, the most important variable in shunt malfunction appears to be the final destination of the catheter tip in relation to the choroid plexus.

Function of parietal and frontal shunts in childhood hydrocephalus.

This study was performed to determine if cerebrospinal fluid (CSF) shunts inserted via the frontal and parietal regions function for similar lengths of time. The medical records of 114 children with CSF shunts were reviewed. In 83 of these cases computerized tomography scans were also available. Ninety percent of the operations were to insert the child's first shunt. The site of insertion, cause of hydrocephalus, patient's age, surgeon, duration of function (time from insertion to malfunction or to latest follow-up evaluation), presence of infection, catheter location within the ventricle, and duration of function of the subsequent shunt were recorded. Data were analyzed by the chi-square, logistic regression, and life-table methods. Shunts had been inserted via the frontal route in 62 children and via the parietal route in 52. The children's ages, causes of hydrocephalus, and infection rates were similar in both groups. Duration of shunt function was predicted by the site of shunt insertion and the catheter position within the ventricles: shunts inserted via the frontal region functioned significantly longer than parietally inserted shunts, both as the initial shunt (Wilcoxon, p = 0.0008) and after a malfunction, and catheters positioned within the ipsilateral frontal horn functioned significantly longer than those in other ventricular locations (Wilcoxon, p = 0.03).