Late intrathecal retraction of a lumboperitoneal shunt

Background

Lumboperitoneal (LP) shunt placement is a good option for treating elderly patients with communicating normal pressure hydrocephalus (NPH) who are also on antiplatelet therapy following endovascular treatment of unruptured bilateral internal carotid artery aneurysms. Here, in an 80-year-old male with an LP shunt, the catheter was "pinched" between adjacent spinous processes, resulting in laceration of the catheter and intrathecal catheter migration.

Case Description

An 80-year-old male was treated with a LP shunt for NPH 1 year after undergoing endovascular treatment of unruptured bilateral internal carotid artery aneurysms. The lumbar catheter was placed at the L2-3 level. Six months later, when he clinically deteriorated, the follow-up computed tomography showed recurrent ventricular enlargement. Further, studies additionally confirmed intrathecal migration of the lumbar catheter, warranting secondary ventriculoperitoneal shunt placement.

Conclusion

Patients with LP shunts may develop lumbar catheter lacerations secondary to a "pinching" effect from adjacent spinous processes, resulting in intrathecal catheter migration.

Revision rates of flow- versus pressure-regulated ventricular shunt valves for the treatment of hydrocephalus in neonates following germinal matrix haemorrhage-a retrospective review

PURPOSE

Neonates with ventricular shunts inserted for hydrocephalus following germinal matrix haemorrhage (GMH) have high rates of shunt revision. The shunt valve plays a key role in regulating the function of the shunt. In this study, we aim to determine if the choice of flow-regulated or pressure-regulated valve used in the initial implantation of a shunt affects the rate of shunt revision.

METHODS

A retrospective cohort comparison study was performed on 34 neonates with hydrocephalus following GMH who underwent placement of a ventricular shunt at the Queensland Children's Hospital from November 2014 to June 2020. The primary outcome examined was the need for revision or replacement of the ventricular shunt after successful initial placement within 2 years of implantation. The secondary outcome examined was the survival time of the shunt.

RESULTS

16 patients had placement of a flow-regulated valve, and 18 patients had placement of a pressure-regulated valve. 14 (87.5%) patients with flow-regulated valves required replacement during the follow-up period. 2 (18.18%) patients with a fixed pressure regulated underwent revision, while 2 (28.57%) programmable pressure-regulated shunts required revision. Patients that had a flow-regulated valve had a statistically significant higher rate of revision compared to those who had a pressure-regulated valve, (87.5% flow vs 22.22% pressure) with a P-value of < 0.001. Valve obstruction was also more common in patients with flow-regulated valves than pressure-regulated valves (4 vs 0) with a P-value of 0.010. Overall mean median survival time was 22.06 months, shunts with flow-regulated valves had a shorter median survival time of 3.19 months compared with over 24 months for pressure-regulated valves with a P-value of < 0.001.

CONCLUSION

Our study suggests that the initial implantation of flow-regulated valves may carry an increased total rate of shunt revision and valve obstruction within the first 2 years following implantation compared to pressure-regulated valves in patients with hydrocephalus following GMH.

Skin landmarks as ideal entry points for ventricular drainage, a radiological study

PURPOSE

Ventricular drainage remains a usual but challenging procedure for neurosurgical trainees. The objective of the study was to describe reliable skin landmarks for ideal entry points (IEPs) to catheterize brain ventricles via frontal and parieto-occipital approaches.

METHODS

We included 30 subjects who underwent brain MRI and simulated the ideal catheterization trajectories of lateral ventricles using anterior and posterior approaches and localized skin surface IEPs. The optimal frontal target was the interventricular foramen and that for the parieto-occipital approach was the atrium. We measured the distances between these IEPs and easily identifiable skin landmarks.

RESULTS

The frontal IEP was localized to 116.8 ± 9.3 mm behind the nasion on the sagittal plane and to 39.7 ± 4.9 mm lateral to the midline on the coronal plane. The ideal catheter length was estimated to be 68.4 ± 6.4 mm from the skin surface to the interventricular foramen. The parieto-occipital point was localized to 62.9 ± 7.4 mm above the ipsilateral tragus on the coronal plane and to 53.1 ± 9.1 mm behind the tragus on the axial plane. The ideal catheter length was estimated to be 48.3 ± 9.6 mm.

CONCLUSION

The IEP for the frontal approach was localized to 11 cm above the nasion and 4 cm lateral to the midline. The IEP for the parieto-occipital approach was 5.5 cm behind and 6 cm above the tragus. These measurements lightly differ from the classical descriptions of Kocher's point and Keen's point and seem relevant to neurosurgical practice while using an orthogonal insertion.

Improving the detection of ventricular shunt disruption using volume-rendered three-dimensional head computed tomography

Hydrocephalus is the most common neurosurgical disorder in children, and cerebrospinal fluid (CSF) diversion with shunt placement is the most commonly performed pediatric neurosurgical procedure. CT is frequently used to evaluate children with suspected CSF shunt malfunction to assess change in ventricular size. Moreover, careful review of the CT images is important to confirm the integrity of the imaged portions of the shunt system. Subtle shunt disruptions can be missed on multiplanar two-dimensional (2-D) CT images, especially when the disruption lies in the plane of imaging. The use of volume-rendered CT images enables radiologists to view the extracranial shunt tubing within the field of view as a three-dimensional (3-D) object. This allows for a rapid and intuitive method of assessing the integrity of the extracranial shunt tubing. The purpose of this pictorial essay is to discuss how volume-rendered CT images can be generated to evaluate CSF shunts in the pediatric population and to provide several examples of their utility in diagnosing shunt disruption. We also address the potential pitfalls of this technique and ways to avoid them.

'Possible shunt malfunction' pathway for paediatric hydrocephalus-a study of clinical outcomes and cost implications

BACKGROUND

Shunt insertion for hydrocephalus is a common paediatric neurosurgery procedure. Shunt complications are frequent with an estimated 20-40% failure rate within the first year, and 4.5% per year subsequently. We have an open-door 'possible shunt malfunction' pathway for children treated with a shunt or endoscopic third ventriculostomy, providing direct ward access to ensure rapid assessment and timely management of children.

OBJECTIVE

To audit the 'possible shunt malfunction' pathway in terms of clinical outcomes (percentage-confirmed shunt dysfunction and number of re-attendances) and costs.

METHODS

Clinical data for patients attending the triage service were prospectively recorded over 7 months-including the number of attendances, previous shunt revisions, shunt type, investigations performed (CT, x-rays), and outcome. Costings (e.g. costs of physician, inpatient stay, investigations) were obtained from the hospital's procurement department.

RESULTS

In the study period, there were 81 attendances by 62 patients and only 16% of attendances resulted in surgical management (either shunt revision or ETV). Approximately 17% of patients re-attended at least once. The average cost per attendance in our pathway was £765.57 ($969.63; €858.73). The total expenditure for the pathway over 7 months was £62,011.03 ($78,540.07; €69,556.81), with inpatient stay making up the biggest percentage of cost (49.2%).

CONCLUSION

Only 16% (13 attendances) of those attending through our pathway required neurosurgical intervention. Investigations for possible blocked shunt come at significant health, social, and financial cost. High rates of shunt failure, re-attendance, investigations, and inpatient stays incur a sizable financial burden to the healthcare system.

Focused Ultrasound Thalamotomy for Essential Tremor in the Setting of a Ventricular Shunt: Technical Report

BACKGROUND

A recent randomized controlled trial of magnetic resonance imaging (MRI)-guided focused ultrasound (FUS) for essential tremor (ET) demonstrated safety and efficacy. Patients with ventricular shunts may be good candidates for FUS to minimize hardware-associated infections.

OBJECTIVE

To demonstrate feasibility of FUS in this subset of patients.

METHODS

A 74-yr-old male with medically refractory ET, and a right-sided ventricular shunt for normal pressure hydrocephalus, underwent FUS to the right ventro-intermedius (VIM) nucleus. The VIM nucleus was directly targeted using deterministic tractography. Clinical outcomes were measured using the Clinical Rating Scale for Tremor.

RESULTS

Shunt components required 6% of the total ultrasound transducer elements to be shut off. Eight therapeutic sonications were delivered (maximum temperature, 64°), leading to a 90% improvement in hand tremor and a 100% improvement in functional disability at the 3-mo follow-up. No complications were noted.

CONCLUSION

This is the first case of FUS thalamotomy in a patient with a shunt. Direct VIM targeting and achievement of therapeutic temperatures with acoustic energy is feasible in this subset of patients.

Association between ventricular shunt catheter calcifications and the development of shunt fracture

BACKGROUND

Calcifications along ventricular catheters have been associated with shunt fractures although it is unknown whether their development predicts whether and when the shunts will fracture.

OBJECTIVE

To determine whether extracranial calcifications found on a radiographic shunt series predicts whether a patient will experience a shunt catheter fracture or complication.

MATERIALS AND METHODS

A retrospective review was performed of pediatric patients with a ventricular shunt placed before 18 years of age and radiographic shunt series. Two thousand, six hundred and thirty shunt series in 523 patients (301 male) were reviewed to identify the development of calcifications around the catheter and fracture. Fifty-one patients were excluded for preexisting calcifications with shunt fracture. (48) Absence of shunt (2) or age (1). Analysis included descriptive statistics, odds ratio and chi-square test results.

RESULTS

Four hundred seventy-two patients were included. Of the 59 shunts in 58 patients that developed calcifications, 23 went on to fracture (39%). Forty shunts without calcification in 37 patients developed fractures. There is a significant positive association between calcification and fracture (Χ²=39.1, P<0.01). It is 6.12 times more likely that a fractured shunt had calcifications compared to a non-fractured shunt having calcifications. Calcifications appeared within an average of 9 years, 10 months (range: 4-14 years) after shunt insertion. Shunt fractures occurred within an average of 5 years, 2 months (range: 6 months-9 years) after the appearance of calcifications with a median patient age of 14.6 years. Nearly all fractures were at or adjacent to the calcifications, most commonly in the neck (17/23; 73.9%).

CONCLUSION

Shunt calcification represents a significant risk for catheter fracture in the pediatric population. Early intervention or closer interval follow-up may be indicated in those found to have calcifications.

Surgical management of craniosynostosis in the setting of a ventricular shunt: a case series and treatment algorithm

PURPOSE

Cerebrospinal fluid diversion via ventricular shunt is a common treatment for hydrocephalus. Change in cranial morphology associated with a sutural fusion has been termed shunt-related or induced craniosynostosis (SRC) or craniocerebral disproportion (CCD). We present a series of patients with SRC who underwent cranial vault remodeling (CVR) and our treatment algorithm.

METHODS

Thirteen patients were retrospectively reviewed who had SRC and CVR; 92% of patients had a ventriculoperitoneal (VP) shunt placed for largely intraventricular hemorrhage of prematurity (69% of patients) at a mean age of 2.2 months. The shunt revision rate was 38.4%, and 54% of patients had a programmable shunt placed initially.

RESULTS

The mean age at time of CVR was 3.6 years old. The most commonly affected sutures (CT confirmed) were the sagittal and coronal sutures, with three patients exhibiting pancraniosynostosis. The mean time from placement of the shunt to CT evidence of sutural fusion was 2.0 years. Abnormal head shape was noted in all 13 patients; 11 of these also had either chronic headaches, papilledema, seizures, or behavioral changes in the setting of functional shunt. Mean follow-up after the initial CVR was 3.3 years. No shunt infections were attributed to the CVR. The families of all patients were contacted and reported improvement in head shape with 60% of families reporting improvement in behavior, 75% reported improvement in headaches, and 40% reported decrease in seizure frequency or intensity. Shunt setting or type was not routinely changed after CVR.

CONCLUSIONS

Our threshold for CVR in SRC is met when shunt malfunction has been ruled out and there are (1) radiographic evidence of craniosynostosis, (2) signs of increased ICP clinically or radiographically, and (3) cranial dysmorphism, i.e., dolichocephaly. The majority of cases of SRC result in improved cranial morphology in addition to some abatement of the symptoms of increased intracranial pressure. Early involvement of an experienced craniofacial/neurosurgical team could allow for early diagnosis and intervention which may prevent progression to more severe deformities. SRC is a complex entity, with multiple etiologies, and a future study is needed.

Low-pressure Hydrocephalus in Children: A Case Series and Review of the Literature

Background

Low-pressure hydrocephalus (LPH) is a rare phenomenon characterized by a clinical picture consistent with elevated intracranial pressure (ICP) and ventricular enlargement, but also a well-functioning shunt and low or negative ICP.

Objective

To report our experience in evaluating this challenging problem.

Methods

Patients with LPH were identified from several sources, including institutional procedural databases and personal case logs. Electronic medical records were reviewed to collect demographic, clinical, surgical, and radiographic data to determine the presence of LPH. Each patient's clinical course, including presentation, management, and outcome, is reported.

Results

Thirty instances of LPH were identified in 29 patients. Eleven cases (37.9%) of LPH were after lumbar puncture (LP), and 19 cases (62.1%) occurred without any preceding spinal procedure. Among the post-LP patients, conservative measures alone were successful in 3 cases (27%); lumbar blood patch was successful in 2 cases (18%); and 6 cases (55%) required external cerebrospinal fluid (CSF) drainage. Of the spontaneous cases, 5 patients did not receive the full spectrum of treatment because of terminal prognosis. Of the remaining 14 patients, 11 (78.6%) required external CSF drainage. Post-LP patients required fewer days of external CSF drainage (median, 4 [range, 0-12] vs median, 11 [range, 0-90]) and had a shorter hospital stay (median, 2 [range, 2-16] vs median, 8 [range, 0-26]).

Conclusion

This study represents the largest series of LPH. Although its pathophysiology remains a mystery, there are a variety of management options. Multiple procedures and a protracted hospital stay are often required to successfully treat LPH.

Ventriculostomy: Frequency, length of stay and in-hospital mortality in the United States of America, 1988-2010

Ventriculostomy is a common neurosurgical procedure. We evaluated a large national sample of data regarding epidemiologic trends in neurosurgical practice relating to ventriculostomy. The USA Nationwide Inpatient Sample (1988 to 2010) provided retrospective data on patients hospitalized who underwent a ventriculostomy procedure. We categorized ventriculostomy procedures as the principal procedure performed for definitive treatment or as any other procedure. We identified 101,577 relevant hospital admissions with an estimated national volume of 507,762 hospital admissions from 1988 to 2010. For all patients, the mean age was 45.0 years and 46.5% were female. The three most common individual principal diagnoses were subarachnoid hemorrhage (19.1%), intracerebral hemorrhage (14.9%), and obstructive hydrocephalus (3.8%). The three most common principal procedures were other excision or destruction of lesion or tissue of brain (16.0%), clipping of aneurysm (13.5%), and temporary tracheostomy (10.8%). Mean length of stay was 20.8 days and in-hospital mortality was 24.5%. In-hospital mortality was associated with emergency admission (multivariate odds ratio 1.98; 95% confidence interval 1.92-2.05), age 45 years or greater (mean of data set) (1.91; 1.85-1.98), multiple ventriculostomies (1.55; 1.44-1.67), and ventriculostomy as a principal procedure (1.39; 1.35-1.44). A total of 32.7% of patients were discharged to home. Most (94.3%) hospitalizations had one, 5.0% had two, and 0.7% multiple (three or more) ventriculostomies performed. Neurosurgeons must be aware of the association of in-hospital mortality, especially during the first days of admission, particularly when ventriculostomy is the principal procedure performed for definitive treatment during the hospitalization.