Proof of the patent subcutaneous fibrous tract in children with V-P shunt malfunction

Shunt Fractures Associated with Intermittent Hydrocephalus: Case Reviews and New Solutions

OBJECTIVE

Although ventriculoperitoneal shunt surgery is the most common method for hydrocephalus treatment, it may lead to serious complications and require surgical interventions. Peritoneal catheter fracture is one of the common complications that may cause intermittent hydrocephalus. If patients with peritoneal catheter fracture have symptoms of hydrocephalus and ventricular dilatation, the treatment algorithm is clear. However, the diagnosis and treatment protocol remains unclear otherwise. In this article, the possible mechanisms of hydrocephalic symptoms, the diagnosis, as well as treatment algorithms are examined.

METHODS

Eight patients with a ventriculoperitoneal shunt who had intermittent hydrocephalic symptoms due to peritoneal catheter fracture but without any radiologically significant ventricular dilatation at Niğde Ömer Halisdemir University from 2018 to 2021 were collected. A new diagnostic algorithm was created. Patient follow-up was performed in each patient as a procedure.

RESULTS

The method that we determined was successful in all our patients. No complications were observed. We have followed the patients with a normal clinic for at least 6 months.

CONCLUSIONS

The provocation test we have formulated always revealed the true cause of the clinic. Thus, on the one hand, with a positive provocation test we recommend revision surgery without waiting for the ventricular dilatation or hydrocephalic symptoms in patients with a fractured peritoneal catheter, considering the results of asymptomatic shunt revision surgery have been reported to be better than those with symptomatic shunt dysfunction; on the other hand, patients with negative provocation tests are saved from unnecessary surgical intervention as well as benefit from true etiologic fast treatment.

Patent Persistent Fibrous Tract in a Patient with Disconnected Lumboperitoneal Shunt

Disconnection of proximal or distal catheter is seen more frequently in the complication of the lumboperitoneal (LP) shunt. A connective tissue sheath that forms around the peritoneal catheter of silicone shunt tubing is a normal biological response to foreign material. The literature did not establish whether the disconnected LP shunt can allow passage of cerebrospinal fluid (CSF) through the disconnected portion. However, proof of the passage of CSF through these sheaths has been reported in only one published study to date. We present a case of a young patient with disconnected LP shunt who reported patent persistent fibrous tract around the tube shunt. In conclusion, asymptomatic patients with shunt disconnection should be evaluated with shuntography for patency of fibrous sheath before removal of the shunt to avoid the possible complications.

A Case of Discontinued Proximal Limb of a Ventriculoperitoneal Shunt With Patent Fibrous Tract

Radionuclide shuntogram is important in the evaluation of cerebrospinal fluid (CSF) shunts complications such as mechanical failure, malpositioning, pseudocyst, or overdrainage. We present here a case of congenital hydrocephalus and posterior fossa cyst with multiple shunt procedures and revisions with breakage of the proximal tube of the ventriculoperitoneal shunt but preserved CSF drainage through the patent fibrous tract. Careful correlation with SPECT/CT images helped confirm the breakage and exclude CSF leak outside of the tract, which was suspected on planar images.

Shunt malfunction mimicking a cystic tumour

Shunt malfunction represents one of the most common problem to deal with in the daily neurosurgical practice. Among the variety of possible presentations, the cyst-like dilatation of the brain around the proximal catheter is one of the most rare and misleading type. The case of a boy with a 'tumour-like' proximal shunt malfunction is described and the pertinent literature is analysed.

Mitigation of reactive human cell adhesion on poly(dimethylsiloxane) by immobilized trypsin

Occlusion or blockage of silicone shunts utilized in the treatment of hydrocephalus is a major challenge that is currently addressed by multiple shunt replacements. Shunt occlusion is caused by the adhesion and proliferation of reactive cells, such as glial and vascular cells, into the lumen of the catheter and on valve components. This in vitro study describes how the adhesive behavior of four human cell types on poly(dimethylsiloxane) (PDMS) surfaces can be suppressed by functionalization with trypsin, a proteolytic enzyme. The covalently conjugated trypsin retained its proteolytic activity and acted in a dose-dependent manner. Trypsin-modified PDMS surfaces supported significantly lower adhesion of normal human astrocytes, human microglia, human dermal fibroblasts, and human umbilical vein endothelial cells compared to unmodified PDMS surfaces (p < 0.0001). Immunofluorescence imaging of cellular fibronectin and quantitative adsorption experiments with serum components indicated that the PDMS surfaces immobilized with trypsin inhibited surface remodeling by all cell types and resisted protein adsorption. The impact of this work lies in the recognition that the well-known proteolytic characteristics of trypsin can be harnessed by covalent surface immobilization to suppress cell adhesion and protein adsorption.

Animal experiments to evaluate complications of foreign materials on silicone with shunt catheters: preliminary results

OBJECTIVE

Use of silicone to manufacture hydrocephalus shunts has been critical for the successful introduction of modern shunt therapy. However reactions to foreign material cause biodegradation, calcification, and massive scarring, and their impact on the still high shunt failure rate might have been undervalued in the past. We established an animal model to simulate the conditions and reactions with the silicone catheter in human patients.

METHODS

We implanted catheters from different hydrocephalus shunt manufacturers available on the world market in 12 four-week old Wistar rats. To mimic shearing forces and tensile stress, the tubes were firmly fixed proximally and distally in a growing rat. The catheters remained in the subcutaneous tissue for 1 year before being removed and studied using scanning electron microscopy and histological studies.

RESULTS

All of the implanted long catheters showed fractures and calcification on their surfaces, whereas the short fragmented catheters did not.

CONCLUSION

The immunological reactions with silicone and the biodegradation of the material can be simulated in this animal model to study details of the pathophysiology of this process.

Radioisotope shuntograms at the Children's Hospital of Eastern Ontario

INTRODUCTION

Nuclear medicine shuntograms using the radiotracer technetium-99m diethylenetriaminepentaacetic acid have been used for many years as an additional method to assess shunt patency and performance.

METHODS

The medical records of all children who had shuntograms performed at the Children's Hospital of Eastern Ontario between January 13, 2000, and January 10, 2003, were retrospectively reviewed. There was a total of 68 procedures in 56 patients with an average age of 9 years 3 months. During the same period there were 123 shunt revisions.

RESULTS

Forty-two shuntograms were reported as normal. Of these, ten were identified to be false negative. Two children with fractured shunts had shuntograms performed in order to assess for cerebrospinal fluid flow patency; the shuntograms were identified to be normal, confirming shunt dependence, and the shunt replaced. Twenty-six shuntograms were reported as abnormal in 24 patients; 17 went on to have surgery and the shunt malfunction was confirmed. Seven patients did not require surgery: five were declared shunt independent, two patients clinically improved after severe constipation was treated.

CONCLUSIONS

Approximately one fourth of all shuntograms reported as normal are not (false-negative rate=25%). Review of five other major studies between 1980 and 2003 have reported false-negative rates between 2 and 36%, which may be explained by variations in shuntogram protocols. A standardized method is proposed.