Rapidly progressive enlargement of the fourth ventricle in the preterm infant with post-haemorrhagic ventricular dilatation

The entity of the trapped fourth ventricle: A review of its history, pathophysiology, and treatment options

An isolated or trapped fourth ventricle is a relatively rare, although serious, adverse effect of hemorrhagic, infectious, or inflammatory processes that involve the central nervous system. This entity usually occurs after successful shunting of the lateral ventricles and may become clinically evident with the development of delayed clinical deterioration. This decline of the neurological status of the patient is evident after an initial period of improvement of the relevant symptoms. Surgical treatment options include cerebrospinal fluid shunting procedures, along with open surgical and endoscopic approaches. Complications related to its management are common and are related with obstruction of the fourth ventricular catheter, along with cranial nerve or brainstem dysfunction. We used the keywords: "isolated fourth ventricle," and "trapped fourth ventricle," in PubMed^® and Web of Science^®. Treatment of the trapped fourth ventricle remains a surgical challenge, although the neurosurgical treatment armamentarium has broadened. However, prompt recognition of the clinical and neurological findings that accompany any individual patient, in conjunction with the relevant imaging findings, is mandatory to organize our treatment plan on an individual basis. The current experience suggests that any individual intervention plan should be mainly based on the underlying pathological substrate of hydrocephalus. This could help us to preserve the patient's life, on an emergent basis, as well as to ensure an uneventful neurological outcome, maintaining at least the preexisting level of neurological function.

Cranial ultrasound findings in preterm germinal matrix haemorrhage, sequelae and outcome

Germinal matrix-intraventricular haemorrhage (GMH-IVH), periventricular haemorrhagic infarction (PHI) and its complication, post-haemorrhagic ventricular dilatation (PHVD), are still common neonatal morbidities in preterm infants that are highly associated with adverse neurodevelopmental outcome. Typical cranial ultrasound (CUS) findings of GMH-IVH, PHI and PHVD, their anatomical substrates and underlying mechanisms are discussed in this paper. Furthermore, we propose a detailed descriptive classification of GMH-IVH and PHI that may improve quality of CUS reporting and prediction of outcome in infants suffering from GMH-IVH/PHI.

Isolated Fourth Ventricle: To Shunt or Stent

BACKGROUND

Of the various management options for isolated fourth ventricle (IFV), fourth ventriculoperitoneal shunts (FVPS) and aqueductal stents (AST) have been the most favored. Though effective, FVPS are often difficult to place and have higher complication rates than conventional ventricular shunts.

OBJECTIVE

To assess the efficacy of AST in IFV and compare the outcome with FVPS.

METHODS

Twenty-five patients surgically treated for IFV were analyzed. In all, a preoperative magnetic resonance imaging assessed the extent of aqueductal obstruction. Patients with an identified short-segment aqueductal stenosis were considered for AST placement; those with long-segment aqueductal obstruction underwent FVPS.

RESULTS

Of the 25, 12 were symptomatic, while 13 were asymptomatic (progressive dilation of IFV in 9, persistent dilation with distortion of the brain stem in 4). In 3 with normal ventricles, the ventricles had to be dilated by externalizing the shunt before placing the stent. Nineteen underwent AST placement, whereas in 6 FVPS was performed. Sixteen patients underwent a simultaneous cerebrospinal fluid diversion procedure and fourth ventricular decompression. At follow-up (mean: 45 mo), stent migration was observed in 2 patients. In the FVPS group, 1 had 2 shunt revisions while another developed reversible cranial nerve paresis. Though a reduction of the IFV was observed with both procedures, the extent of reduction was more with FVPS.

CONCLUSION

Both FVPS and AST are effective in managing IFV. The extent of aqueductal obstruction and degree of ventriculomegaly are often the deciding factors in choosing the management option.

Endoscopic Treatment of Isolated Fourth Ventricle

BACKGROUND:

Treatment of an isolated fourth ventricle should be considered when clinical symptoms or a significant mass effect occur.

OBJECTIVE:

To report clinical and radiographic outcomes after endoscopic transaqueductal or transcisternal stent placement into the fourth ventricle.

METHODS:

In 19 patients (age, 34th week of gestation-20 years; median age, 17.5 months), 22 endoscopic procedures were performed. Either an aqueductoplasty or, in cases with a supratentorially extended fourth ventricular component, an interventricular fenestration was performed. In all patients, a stent connected to the cerebrospinal fluid--diverting shunt was placed through the fenestration. Surgical complications and radiological and clinical outcomes are reported.

RESULTS:

All 19 patients had a mean follow-up of 26.9 ± 18.2 months. No persisting neurological complications were observed; 27.3% of patients experienced complete resolution of presenting symptoms, whereas 68.3% demonstrated partial resolution. Symptoms with short duration (< 4 weeks) resolved completely, whereas long-standing symptoms partially improved. Short-term shunt complications (n = 2; insufficient catheter placement and subdural hygroma) and a need for long-term stent revisions (n = 3; stent retraction and shunt revision for other causes) were observed. The mean fourth ventricular volume was reduced after surgery (44.2 ± 25.8 to 23.1 ± 21.9 mL; P < .01). Pontine diameter increased from 0.9 ± 0.3 to 1.2 ± 0.3 cm (P < .01) after surgery. Both effects were still demonstrated on later radiological follow-up of 24.4 ± 14.2 months (fourth ventricular size, 24.7 ± 28.1 mL; P < .01; pontine diameter, 1.3 ± 0.3 cm; P < .01).

CONCLUSION:

The clinical and radiological outcomes after endoscopic aqueductoplasty and interventriculostomy in children with an isolated fourth ventricle indicate that this procedure is feasible, effective, and safe.

Management strategies for treatment of the trapped fourth ventricle

BACKGROUND

An isolated or trapped fourth ventricle (TFV) is an occasional, serious sequela of hemorrhagic, infectious, or inflammatory conditions of the central nervous system. The TFV usually occurs after successful shunting of the lateral ventricles. It may be heralded by delayed clinical deterioration after an initial period of symptomatic improvement. The typical clinical findings suggest an expanding posterior fossa mass lesion. Surgical treatments include CSF diversionary procedures as well as open and endoscopic approaches. Complications related to the treatment of the TFV are common and relate to catheter obstruction and cranial nerve or brainstem dysfunction.

METHODS

The author reviews the clinical features, pathophysiology, and available treatment options for the TFV, with special reference to complication avoidance and advances in ventriculoscopy and frameless stereotaxy.

CONCLUSIONS

Treatment of the TFV remains a formidable challenge. However, prompt recognition and intervention may aid in the preservation of life and neurological function.

Endoscopic aqueductoplasty and interventriculostomy for the treatment of isolated fourth ventricle in children

OBJECTIVE

There are different approaches for the treatment of isolated fourth ventricle in children, including a suboccipital ventriculoperitoneal shunt, suboccipital craniotomy with microsurgical fenestration, and endoscopic fenestration. We discuss the indications, surgical methods, and outcome of 18 patients who underwent endoscopic treatment for isolated fourth ventricle.

METHODS

We retrospectively reviewed the medical histories of 18 patients with an isolated fourth ventricle. Surgical procedures included endoscopic aqueductoplasty, endoscopic aqueductoplasty with a stent, endoscopic interventriculostomy (lateral ventricle or third ventricle to fourth ventricle), and endoscopic interventriculostomy with a stent. Operations were performed between July 1997 and June 2002. The mean age of the patients at the time of surgery was 3 years. The mean follow-up was 29 months. All patients had a supratentorial ventriculoperitoneal shunt.

RESULTS

Clinical symptoms (impairment of consciousness, tetraparesis, and ataxia) improved in all patients. Reduction of the size of the fourth ventricle was observed in all patients. Seven patients required reoperation because of restenosis (39% revision rate). Restenosis occurred between 2 weeks and 7 months after surgery (average, 3 mo). Four patients underwent reoperation with stent placement, and three patients underwent reaqueductoplasty. We had the following complications: one infection, one asymptomatic subdural hygroma, one transient oculomotor paresis, and one permanent oculomotor paresis (4 [22%] of 18 patients).

CONCLUSION

The significant failure rate of fourth ventricle shunts has led to the development of alternative treatment methods. Endoscopic aqueductoplasty or interventriculostomy presents an effective, minimally invasive, and safe procedure for the treatment of isolated fourth ventricle in pediatric patients. Compared with suboccipital craniotomy and microsurgical fenestration, endoscopic aqueductoplasty is less invasive, and compared with fourth ventricle shunts, it is more reliable and effective.