Failed Ventriculoperitoneal Shunt: Is Retrograde Ventriculosinus Shunt a Reliable Option?

The Pathogenesis Based on the Glymphatic System, Diagnosis, and Treatment of Idiopathic Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a rare neurological disorder with no clear prevalence factors and is a significant danger to the elderly. The intracranial glymphatic system is the internal environment that maintains brain survival and metabolism, and thus fluid exchange changes in the glymphatic system under various pathological conditions can provide important insights into the pathogenesis and differential diagnosis of many neurodegenerative diseases such as iNPH. iNPH can be diagnosed using a combination of clinical symptoms, imaging findings and history, and cerebrospinal fluid biomarkers due to the glymphatic system disorder. However, only few researchers have linked the two. Shunt surgery can improve the glymphatic system disorders in iNPH patients, and the surgical approach is determined using a combination of clinical diagnosis and trials. Therefore, we have composed this review to provide a future opportunity for elucidating the pathogenesis of iNPH based on the glymphatic system, and link the glymphatic system to the diagnosis and treatment of iNPH. The review will provide new insights into the medical research of iNPH.

Suprahepatic space as an alternative site for distal catheter insertion in pseudocyst-associated ventriculoperitoneal shunt malfunction

OBJECTIVE

Distal catheter malfunction due to pseudocyst formation or intraabdominal adhesion is a significant problem, especially in pediatric patients who have limited sites for distal catheter insertion. In this study, the authors present a series of 12 patients with intractable distal shunt malfunctions due to peritoneal pseudocyst formation who underwent distal catheter replacement in the suprahepatic space to reduce the risk of distal catheter malfunction.

METHODS

Twelve consecutive patients with shunt malfunction due to pseudocyst formation who had undergone ventriculosuprahepatic shunting from 2014 to 2019 were identified. According to medical records, after primary evaluations, shunt removal, and antibiotic therapy, they underwent revision surgeries with placement of a distal catheter into the suprahepatic space.

RESULTS

Nine boys and 3 girls, ranging in age from 5 months to 14 years, with one or more episodes of pseudocyst formation, underwent shunt revision with placement of a distal catheter into the suprahepatic space. After a median follow-up of 31 months, none of the patients experienced further distal malfunction.

CONCLUSIONS

The suprahepatic space appears to be a safe place to secure the distal end of a ventricular catheter following pseudocyst formation, with less risk of re-adhesion. This lower risk might be attributable to the lack of omentum in the suprahepatic space.

From the heart to the bladder-particularities of ventricular shunt topography and the current status of cerebrospinal fluid diversion sites

Hydrocephalus represents the pathological elevation of cerebrospinal fluid (CSF) levels as a consequence of various embryological or acquired defects. Although the classic method of treatment is by means of diverting the CSF from the ventricular system towards the peritoneum, there are other sites of diversion that have proven their efficiency through time, in the context of complications related to the more common option of intraperitoneal insertion. The aim of the review is to assess and organize a database of all the types of shunt locations from the oldest shunt attempts until present, using Pubmed and Medline and to underline the particularities related to technique, indications, complications and associated epidemiological background. Current literature reveals up to 36 sites of diversion of CSF with a diverse topography varying from cephalic regions such as venous sinuses or mastoid bone, thoracic elements such as the heart or the pleura and abdominopelvic segments such as the peritoneum or the urinary bladder. Several atypical locations were studied such as the fallopian and intestinal shunts. Although ventriculoperitoneal and ventriculoatrial shunts are the most commonly used shunts today, there are some systems such as the ventriculosinusal and ventriculolymphatic shunts that prove to be equally as efficient. The successful treatment of hydrocephalus requires a complete comprehension of the indications and therapeutic options and a reliable evaluation of the risks and possible complications. The profile of cerebral ventricular shunts is highly dynamic and the spectrum of cerebrospinal fluid diversion offers multiple solutions in the benefit of the patient.

Treating Hydrocephalus with Retrograde Ventriculosinus Shunt: Prospective Clinical Study

BACKGROUND

Since the 1950s, hydrocephalus has been be treated with cerebrospinal fluid (CSF) shunts, usually to the peritoneal cavity or to the right cardiac atrium. However, because of their siphoning effect, these shunts lead to nonphysiologic CSF drainage, with possible comorbidity and high revision rates. More sophisticated shunt valve systems significantly increase costs and technical complexity and remain unsuccessful in a subgroup of patients. In an attempt to obtain physiologic CSF shunting, many neurosurgical pioneers shunted towards the dural sinuses, taking advantage of the physiologic antisiphoning effect of the internal jugular veins. Despite several promising reports, the ventriculosinus shunts have not yet become standard neurosurgical practice.

METHODS

In this single-center prospective clinical study, we implanted the retrograde ventriculosinus shunt, as advocated by El-Shafei, in 10 patients. This article reports on our operation technique and long-term outcome, including 4 patients in whom this shunt was implanted as a rescue operation.

RESULTS

Implantation of a ventriculosinus shunt proved to be feasible, warranting physiologic drainage of CSF. However, in only 3 of 14 patients, functionality of the retrograde ventriculosinus shunt was maintained during more than 6 years of follow-up. In our opinion, these shunts fail because present venous access devices are difficult to implant correctly and become too easily obstructed. After discussion of possible causes of this frequent obstruction, a new dural venous sinus access device is presented.

CONCLUSION

An easy-to-implant and thrombogenic-resistant dural venous sinus access device needs to be developed before ventriculosinus shunting can become general practice.

A non-hydrocephalic goat experimental model to evaluate a ventriculosinus shunt

The ventriculosinus shunt is a promising treatment for hydrocephalus. Currently, different shunt techniques exist, and it is not clear whether one is preferable. This pilot study reports on a non-hydrocephalic goat model (Saanen breed) that provides opportunities to evaluate and optimize several aspects of the ventriculosinus shunt technique. Analysis of the coagulation properties of 14 goats by a viscoelastic coagulation monitor showed that goats have a hypercoagulable state compared to humans. This property can be partially counteracted by antiplatelet drugs. During implantation of a ventriculosinus shunt, a pulsatile reflux of blood was observed. After implantation, the animals recovered to their preoperative state, and none of them developed a superior sagittal sinus thrombosis. Evaluation of the shunts after 16 days showed an obstructing luminal clot. Several model-related factors may have promoted this obstruction: the absence of hydrocephalus, the hypercoagulability of caprine blood and the smaller dimensions of the caprine superior sagittal sinus. However, the pulsatile reflux of blood, which is caused by the compliance of the shunt system distal to the valve, may have been an important factor as well. In conclusion, the non-hydrocephalic goat model limits animal suffering and simplifies the study protocol. This model allows researchers to evaluate their implantation technique and shunt hardware but not the efficacy of the treatment or shunt survival.

Cerebrospinal Fluid Shunting Complications in Children

Although cerebrospinal fluid (CSF) shunt placement is the most common procedure performed by pediatric neurosurgeons, shunts remain among the most failure-prone life-sustaining medical devices implanted in modern medical practice. This article provides an overview of the mechanisms of CSF shunt failure for the 3 most commonly employed definitive CSF shunts in the practice of pediatric neurosurgery: ventriculoperitoneal, ventriculopleural, and ventriculoatrial. The text has been partitioned into the broad modes of shunt failure: obstruction, infection, mechanical shunt failure, overdrainage, and distal catheter site-specific failures. Clinical management strategies for the various modes of shunt failure are discussed as are research efforts directed towards reducing shunt complication rates. As it is unlikely that CSF shunting will become an obsolete procedure in the foreseeable future, it is incumbent on the pediatric neurosurgery community to maintain focused efforts to improve our understanding of and management strategies for shunt failure and shunt-related morbidity.