The role of shuntography in diagnosis of mechanic complications after implantation of ventriculoperitoneal shunts in patients with idiopathic normal pressure hydrocephalus: a retrospective clinical evaluation

Radionuclide Shunt Scintigraphy Technique in Diagnosing Ventriculoperitoneal Shunt Malfunction and Patency: A Case Study and Review of Literature

Although cerebrospinal fluid (CSF) diversion through ventriculoperitoneal shunt insertion is a conventional treatment for hydrocephalus, shunt malfunction is a common complication, making its diagnosis critical. We report a patient with a background of congenital hydrocephalus and an in situ ventriculoperitoneal shunt (VPS) exhibiting worsening papilledema with raised lumbar puncture opening pressures, indicating a possible VPS malfunction. A review of the current diagnostic methods for VPS malfunction, focusing on radionuclide scintigraphy, was conducted in this case review. VPS radionuclide scintigraphy was successfully performed in our patient using intrathecal administration of Tc-99m diethylene-triamine-penta-acetic acid (DTPA) into the CSF shunt reservoir, facilitating tracer visualization. A review of the patient's case notes and subsequent literature review identified several methods for diagnosing VPS malfunction to determine the correct shunt malfunction segment and respective corrective measures. VPS radionuclide scintigraphy in our patient confirmed a patent distal peritoneal catheter, although a transient proximal ventricular catheter blockage and malfunction remained a possibility. The literature review highlighted successful worldwide applications of substance dilution, thermal transfer, ultrasound, and Doppler techniques for diagnosing VPS malfunction with radionuclide shunt scintigraphy. Evaluating VPS function comprises various methods and is significantly important to prevent adverse consequences for the patient, allowing prompt revision surgery directed at the site of obstruction or malfunction. Hence, VPS malfunction diagnosis is vital for leading appropriate corrective measures, with radionuclide shunt scintigraphy functioning as a non-invasive method.

Nonadjustable state of programmable shunt valve: obstruction of middle cranial fossa arachnoid cyst-peritoneal shunt

BACKGROUND

A nonadjustable state of the programmable shunt valve is a rare phenomenon. This case report aims to explore the cause of pressure adjustment dysfunction in a programmable shunt valve in a middle cranial fossa arachnoid cyst-peritoneal shunt patient and to underscore this dysfunction as an indicator of shunt valve obstruction.

CASE PRESENTATION

A child with a ruptured giant arachnoid cyst in the left middle cranial fossa presented with acute intracranial hypertension following head trauma. The initial cysto-peritoneal shunt surgery rapidly alleviated symptoms, including headaches, vomiting, and left cranial nerve palsy, stabilizing the clinical condition. However, between 20 and 24 months after the initial shunt surgery, the patient developed intermittent shunt dysfunction, experiencing recurrent headaches and vomiting, during which the programmable valve's pressure setting had become fixed and was no longer adjustable. A second surgery was then performed to remove the existing shunt, excise the fibrotic cyst wall, fenestrate the basal cistern, and establish temporary subdural drainage. During this operation, extensive fibrosis of the cyst wall in the subdural space was discovered, forming a tough and hypertrophic fibrotic membrane that encased the cerebral hemispheres. This fibrotic material nearly filled the shunt valve chamber, causing valve obstruction and immobilizing the pressure control rod, resulting in pressure adjustment dysfunction. As the patient could not maintain stability without continuous drainage, a third surgery was ultimately necessary to place a subdural-peritoneal shunt. Five years of follow-up revealed no significant clinical symptoms, and the patient has maintained a normal life.

CONCLUSION

Shunt valve obstruction is an underestimated cause of shunt system failure, with no current definitive method for early diagnosis. Fibrotic deposition is a primary mechanism underlying shunt valve obstruction. Pressure adjustment dysfunction in a programmable shunt valve serves as a reliable indicator of shunt valve obstruction. Further research should prioritize the treatment and prevention of shunt valve obstructions to improve outcomes in neurosurgical practice.

To Investigate the Effect of Magnetic Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI) in the Diagnosis of Mild Craniocerebral Injury

In order to assess the value of magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) in microscopic brain scans. Diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRI) changes over time in patients with traumatic brain injury (TBI) show a relationship between recovery from coma and overall Glasgow prognostic parameters. The value of DTI combined with MRI in evaluating TBI has been investigated. 10 patients with TBI received 10 evaluations of magnetic resonance imaging, DTI and MRI scans. Thalamic plate nucleus, reticular nucleus, and retinal developmental activity were measured in normal controls and TBI coma (2-3 weeks) and mild (>4 weeks) patients. Anisotropy, mean diffusion coefficient, axial diffusion coefficient, and radial diffusion coefficient were measured using MRI together with acetylaspartic acid, choline, creatinine, and lactic acid. Independent control t-tests were conducted between controls and TBI patients, and 1-test paired between moderate and severe injuries, and regression and correlation were evaluated. Evaluated for all measures and treatments. DTI and MRI scores in TBI patients differed from normal controls. DTI and MRI can predict the prognosis of TBI patients better. The limitations of the thalamus-retinal activation system are gradually restored. axial diffusion coefficient and radial diffusion coefficient can be used to evaluate the reliability of comatose patients with TBI. DTI and MRI scans of the patient's brain can predict recovery and guide treatment in TBI coma patients.

Weight and Abdominal Pressure-Induced Shunt Trouble in Patients With Shunted Normal Pressure Hydrocephalus: A Comprehensive Study on Pressure Environment of Shunt System

Objectives

We identified a new type of shunt malfunction (SM) in patients with normal pressure hydrocephalus (NPH). It is induced by weight change and can be treated with valve readjustment. There were two types of SM as follows: Underdrainage induced by the weight gain and overdrainage induced by the weight loss. This study aims to elucidate this mechanism by assessing the shunt pressure environment.

Methods

The total pressure environment of the shunt system was prospectively studied in patients with shunted NPH at Osaka Medical College Hospital from 1999 to 2005. We measured the pressure environment during the initial pressure setting of the valve by the intracranial pressure (ICP) guide, after setting the valve, and when SM was suspected. We evaluated ICP, intra-abdominal pressure (IAP), and hydrostatic and perfusion pressures of the shunt system in the sitting and supine positions. The target ICP for valve setting was empirically set at the range from −8 to −13 mm Hg in the sitting position, referring to the external auditory meatus. During the study period, we identified five cases of SM induced by weight change and assessed the changes in the pressure environment across pre-SM, SM, and post-SM.

Results

In four cases of underdrainage, gait disturbance worsened with an average weight gain of 6.8 ± 1.2 kg. With weight gain, IAP and ICP increased by 8.8 ± 1.6 and 4.8 ± 1.0 mm Hg, respectively. Consequently, ICP increased to −6.5 ± 1.9 mm Hg. One overdrainage patient developed an asymptomatic chronic subdural hematoma (CSDH) with a weight loss of 10 kg. With the weight loss, both IAP and ICP decreased by 5 mm Hg, and concomitantly, ICP decreased to −18 mm Hg. In all patients, the valve readjustment restored their ICP to the target pressure. After the valve readjustment, the gait disturbance improved immediately, and the CSDH disappeared after 1 month.

Conclusion

In patients with shunts, the weight change was linked to ICP via IAP. Due to the weight change, the underdrainage occurred when ICP was above the target pressure, and the overdrainage occurred when ICP was below it. We named this SM as the weight and abdominal pressure-induced shunt trouble. The patients with SM along with weight changes should be the first to be tried for the valve readjustment.