Common and Uncommon Causes of Ventriculoperitoneal Shunt Malfunction Diagnosed on Plain Radiographs

Reducing radiation exposure and costs: CT body scout views with an enhanced protocol versus conventional radiography after shunt surgery

OBJECTIVE

Ventriculoperitoneal shunt implantation has become standard treatment for cerebrospinal fluid diversion, besides endoscopic third ventriculostomy for certain indications. Postoperative X-ray radiography series of skull, chest and abdomen combined with cranial CT are obtained routinely in many institutions to document the shunt position and valve settings in adult patients. Measures to reduce postoperative radiation exposure are needed, however, there is only limited experience with such efforts. Here, we aim to compare routine postoperative cranial CT plus conventional radiography series (retrospective arm) with cranial CT and body scout views only (prospective arm) concerning both diagnostic quality and radiation exposure.

PATIENTS AND METHODS

After introduction of an enhanced CT imaging protocol, routine skull and abdomen radiography was no longer obtained after VP shunt surgery. The image studies of 25 patients with routine postoperative cranial CT and conventional radiography (retrospective arm of study) were then compared to 25 patients with postoperative cranial CT and CT body scout views (prospective arm of study). Patient demographics such as age, sex and primary diagnosis were collected. The image quality of conventional radiographic images and computed tomography scout views images were independently analyzed by one neurosurgeon and one neuroradiologist.

RESULTS

There were no differences in quality assessments according to three different factors determined by two independent investigators for both groups. There was a statistically significant difference, however, between the conventional radiography series group and the CT body scout view imaging group with regard to radiation exposure. The effective dose estimation calculation yielded a difference of 0.05 mSv (two-tailed t-test, p = 0.044) in favor of CT body scout view imaging. Furthermore, the new enhanced protocol resulted in a reduction of cost and the use of human resources.

CONCLUSION

CT body scout view imaging provides sufficient imaging quality to determine shunt positioning and valve settings. With regard to radiation exposure and costs, we suggest that conventional postoperative shunt series may be abandoned.

Odd presentation of shunt malfunction: a case series and review of literature

OBJECTIVE

Children with previous ventriculoperitoneal shunt (VPS) insertion due to hydrocephalus may refer to the hospital with various clinical complaints. Shunt malfunction is frequently diagnosed in these children necessitating shunt revision. Although increased head circumference, setting sun eye in younger children, and headache, nausea/vomiting, loss of consciousness, visual disturbance, and other signs of intracranial hypertension are common clinical manifestations of shunt malfunction, some patients may present with odd or unusual symptoms. Here, we present a series of patients with shunted hydrocephalus who presented with odd and unexpected clinical manifestations of shunt malfunction.

METHODS

Eight children with shunt malfunction were enrolled in this series. The age, sex, age of shunting, etiology of hydrocephalus and management, post-shunt insertion symptoms/sign, revision surgery, outcome, and follow-up were evaluated.

RESULTS

Patients were aged from 1 to 13 years (mean, 6.38 years). There were 5 males and 3 females. The odd presentation associated with shunt malfunction included facial palsy in three children, ptosis in 3 children, and torticollis and dystonia each in one child. All patients underwent shunt revision except for one patient in whom a new shunt was inserted. Follow-up showed improvement of the symptoms in all patients.

CONCLUSION

In this series, we reported eight patients with unusual signs and symptoms following shunt malfunction that were successfully diagnosed and managed.

Ventriculo-atrial shunt. Comparison of an ultrasound-guided peel-away technique versus conventional technique in the management of normal pressure hydrocephalus: A retrospective cohort

Background:

Normal pressure hydrocephalus (NPH) is a common neurodegenerative syndrome among the elderly characterized by ventriculomegaly and the classic triad of symmetric gait disturbance, cognitive decline and urinary incontinence. To date, the only effective treatment is a cerebrospinal fluid shunting procedure that can either be ventriculo-atrial, ventriculo-peritoneal, or lumbo-peritoneal shunt. The conventional ventriculo-atrial shunt uses venodissection, whereas the peel-away is a percutaneous ultrasound (US)-guided technique that shows some advantages over conventional technique. We sought to compare perioperative complication rates, mean operating time and clinical outcomes for both techniques in NPH patients at our institution.

Methods:

A retrospective cohort-type analytical study was conducted, using clinical record data of patients diagnosed with NPH and treated at our center from January 2009 to September 2019. Parameters to be compared include: Perioperative complication rates, intraoperative bleeding, mortality, and mean operating time. Perioperative complication rates are those device-related such as shunt infection, dysfunction, and those associated with the procedure. Complications are further classified in immediate (occurring during the first inpatient stay), early (within the first 30 days of surgery), and late (after day 30 of surgery).

Results:

A total of 123 patients underwent ventriculo-atrial shunt. Eighty-two patients (67%) underwent conventional venodissection technique and 41 patients (33%) underwent a peel-away technique. Immediate complications were 3 (3.6%) and 0 for conventional and peel-away groups, respectively. Early complications were 0 and 1 (2.4%) for conventional and peel-away groups, respectively. Late complications were 5 (6.1%) and 2 (4.9%) for conventional and peel-away groups, respectively. Mean operating time was lower in the peel-away group (P = 0.0000) and mortality was 0 for both groups.

Conclusion:

Ventriculo-atrial shunt is an effective procedure for patients with NPH. When comparing the conventional venodissection technique with a percutaneous US-guided peel-away technique, the latter offers advantages such as shorter operating time and lower perioperative complication rates.

Umbilical hernia causing ventriculoperitoneal shunt dysfunction: illustrative cases

BACKGROUND

When ventriculoperitoneal (VP) shunts and umbilical hernias coexist in the same patient, unique complications can occur. Typically, these are readily identified problems such as cerebrospinal fluid (CSF) fistulas or entrapment of the peritoneal catheter in the hernia. The authors present cases of two children whose VP shunt dysfunction resolved after repair of their umbilical hernias.

OBSERVATIONS

The authors present two cases of infant patients with shunted hydrocephalus and umbilical hernias. In both cases, the patients presented with distal shunt malfunctions not due to infection. Their shunt function improved once the umbilical hernia was repaired by pediatric surgery. Neither has required shunt revision since umbilical hernia repair.

LESSONS

Although there are case reports of VP shunts eroding through the umbilicus, developing CSF fistulas, or becoming trapped inside umbilical hernias, there is no case of VP shunt dysfunction caused by just the presence of an umbilical hernia. The authors suspect that the catheter may intermittently enter and exit the hernia. This may cause intermittent obstruction of the distal catheter, or inflammation in the hernia may occur that limits CSF absorption.

Dynamic Occlusion of Distal Ventriculoperitoneal Shunt Catheter after Infusion Port Placement: A New Shunt Malfunction

Shunt failure requiring reintervention remains a common complication of hydrocephalus treatment. Here, we report a novel cause of mechanical shunt obstruction in an adult patient: position-dependent intermittent occlusion via an infusion port catheter. A 51-year-old woman with a grade II oligodendroglioma presented in a delayed fashion following surgery with a pseudomeningocele. She underwent ventriculoperitoneal shunt placement due to communicating hydrocephalus, resolving her pseudomeningocele. Shortly thereafter, she underwent placement of a subclavian infusion port at an outside institution. Her pseudomeningocele returned. Imaging demonstrated close proximity of her port catheter to the shunt catheter overlying the clavicle. Her shunt was tapped demonstrating a patent ventricular catheter with normal pressure. She underwent shunt exploration after her pseudomeningocele did not respond to valve adjustment. Intraoperative manometry demonstrated head position-dependent distal catheter obstruction. Repeat manometry following distal catheter revision demonstrated normal runoff independent of position. Her pseudomeningocele was resolved on follow-up. To our knowledge, this is the only reported case of intermittent, position-dependent distal catheter obstruction. Shunted patients with concern for malfunction following subclavian infusion port placement should be evaluated for possible dynamic obstruction of their distal catheter when the two catheters are in close proximity along the clavicle.

Patterns and prognosis of ventriculoperitoneal shunt malfunction among pediatrics in Saudi Arabia

Objectives:

To examine the predictors of pediatric ventriculoperitoneal (VP) shunt malfunction in a university hospital.

Methods:

A retrospective cohort was conducted. Patients under 18 years old who underwent VP shunt revision at least once between 2016 and 2019 were included. Data were stratified based on age, gender, diagnosis, type of valve, valve position, cause of revision, and part revised.

Results:

A total of 45 patients (64% males and 36% females) were included in this study. Eighty-two revision surgeries were identified. The most common revised part was the entire shunt system. The most common type of valve which required revision was the low-pressure valve (15.5%). Since a p-value of less than 0.05 was considered significant, no significant differences among the 4 groups for different points.

Conclusions:

Younger age at initial VP shunt insertion is associated with a higher rate of shunt malfunction. Valve mechanical failures followed by infections are the most common causes for the first 3 revisions. A prospective multi-center study to confirm the current findings is recommended.

Image quality of EOS low-dose radiography in comparison with conventional radiography for assessment of ventriculoperitoneal shunt integrity

OBJECTIVE

Patients with shunted hydrocephalus often accumulate high levels of radiation over their lifetimes during evaluation of hardware integrity. Current practice involves the use of a series of conventional radiographs for this purpose. Newer low-dose EOS radiography is currently used to evaluate scoliosis but has not been explored to evaluate shunt integrity on a large scale. The goal of this study was to compare the quality of imaging using EOS low-dose radiography to conventional radiography to evaluate shunt tubing.

METHODS

A retrospective chart review was performed on 57 patients who previously had both conventional radiographs and low-dose EOS images of their cerebral shunt tubing from 2000 to 2018. Patient demographics (age, sex, type of shunt tubing, primary diagnosis) were collected. Conventional radiographic images and low-dose EOS images were independently analyzed by a neurosurgeon and neuroradiologist in three categories: image quality, delineation of shunt, and distinction of shunt compared to adjacent anatomy.

RESULTS

All patients had shunted hydrocephalus due to spina bifida and Chiari type II malformation. Ratings of EOS and conventional radiographic images by both raters did not differ significantly in terms of image quality (rater 1, p = 0.499; rater 2, p = 0.578) or delineation of shunt (p = 0.107 and p = 0.256). Conventional radiographic images received significantly higher ratings than EOS on the ability to distinguish the shunt versus adjacent anatomy by rater 1 (p = 0.039), but not by rater 2 (p = 0.149). The overall score of the three categories combined was not significantly different between EOS and conventional radiography (rater 1, p = 0.818; rater 2, p = 0.186). In terms of cost, an EOS image was less costly than a conventional radiography shunt series ($236-$366 and $1300-$1547, respectively). The radiation dose was also lower for EOS images, with an effective dose of 0.086-0.140 mSv compared to approximately 1.6 mSv for a similar field of view with conventional radiography.

CONCLUSIONS

The image quality of low-dose EOS radiography does not significantly differ from conventional radiography for the evaluation of cerebral shunts. In addition, EOS affords a much lower radiation dose and a lower cost.

Disappearance of a Distal Shunt Catheter: A Case Report of an Unusual Cause of Shunt Malfunction

Shunt malfunction is a common complication in patients who undergo ventriculoperitoneal shunt (VPS) placement for the treatment of hydrocephalus. A plethora of reports regarding shunt malfunctions due to distal catheter migration have been demonstrated in the literature. However, to our knowledge, there have been no reports thus far of shunt malfunctions caused by the complete disappearance of a distal catheter. A 70-year-old man was admitted to our hospital for progressive gait disturbance beginning approximately 5 months ago. He received a VPS for posthemorrhagic hydrocephalus and was doing well over the course of 18 months of follow-up. Since no increase in the size of the ventricle was observed on brain computed tomography taken at the outpatient clinic, we tried to readjust the pressure setting of his programmable shunt valve to relieve his symptoms. Without any progression, we discovered later by chance that the distal shunt catheter was missing. Shunt revision surgery was performed. At the 2-year follow-up, a slight improvement in gait was observed. Although it is very rare, the distal catheter can disappear without any noticeable symptoms. If shunt malfunction is suspected, it is important to check whether the entire shunt system is structurally intact.

[Placement of ventricle peritoneal shunt in the adult patient. A new protocol]

Introducción:

La colocación de un shunt ventrículo-peritoneal, a pesar de considerarse un procedimiento de baja complejidad, puede devenir en una serie de complicaciones. Nuestro equipo quirúrgico desarrolló e implementó a partir de junio de 2016 un nuevo protocolo. El objetivo del presente trabajo es: describir e ilustrar paso a paso la técnica quirúrgica utilizada y demostrar que el uso del “nuevo protocolo” disminuye significativamente las complicaciones asociadas al procedimiento.

Material y métodos:

Desde junio de 2014 a noviembre de 2017 se intervinieron 184 pacientes en relación a sistemas de derivación de LCR. Se realizó un estudio retrospectivo que incluyó los pacientes con colocación primaria de shunt ventrículo-peritoneal (n=114). El seguimiento promedio fue de 14,2 meses (rango 6-38). Para el análisis estadístico se dividió a la muestra en 2 grupos: “protocolo previo” (n=59) y “nuevo protocolo” (n=55). Para describir la técnica quirúrgica se utilizó el archivo fotográfico y los partes quirúrgicos.

Resultados:

Se describió la técnica quirúrgica en 7 fases. La cantidad de pacientes con alguna complicación fue significativamente menor luego de implementar el “nuevo protocolo” (20% versus 39% respectivamente; p=0,04). En el grupo “nuevo protocolo” no se registró infección alguna asociada a shunt.

Conclusión:

Se presentó e ilustró, de manera clara y detallada, la técnica de colocación de shunt ventrículo-peritoneal en 7 fases. Esta técnica, junto a una serie de normas, constituyen un “nuevo protocolo”. La aplicación de éste disminuyó significativamente las complicaciones asociadas al procedimiento. La tasa de infección “cero” no es una utopía.

Use of EOS Low-Dose Biplanar X-Ray for Shunt Series in Children with Hydrocephalus: A Preliminary Study

INTRODUCTION

Shunt series (SS) are a common diagnostic tool used to verify shunt integrity. SS include X-ray films of the skull, chest, and abdomen and often are performed either when a shunted patient presents with suspected shunt malfunction or as a screening test to identify shunt disconnections or dislodgment. EOS low-dose biplanar X-rays are associated with significantly reduced radiation doses compared with ordinary X-rays and are used for various indications. This is the first publication on the use of EOS as a SS technique.

METHODS

Over a period of 6 months, EOS were performed at our center for various orthopedic indications, mostly for scoliosis evaluation. Nine children (<20 years of age) had a ventriculoperitoneal shunt and served as the study group. We retrospectively reviewed shunt visibility and integrity in the EOS scans as well as regular SS or plain spinal X-rays.

RESULTS

Three patients had bilateral shunts, and 8 had previous X-rays for comparison. In all patients, the shunt integrity was easily demonstrated on the EOS images. Two patients had an identified shunt disconnection confirmed on the EOS images. No shunt-related information was missed on the EOS compared with the other X-ray images.

CONCLUSIONS

These preliminary results suggest that EOS may be used as an alternative technology to demonstrate shunt integrity instead of regular X-ray SS. Favorable shunt visibility without the need for multiple radiation exposures and image processing (such as stitching) results in a significantly shorter examination time and significant less radiation.