Ventriculoperitoneal shunt migration and coiling: A report of two cases.

Migration of the proximal and distal catheters of the ventriculoperitoneal shunt is a very rare event. Here, we report two infants with hydrocephalus and ventriculoperitoneal shunt who presented later with shunt coiling and migration. The first infant was admitted with scalp swelling around proximal incision 3 months after shunt insertion and migration and coiling of both ventricular and peritoneal catheters occurred under the scalp at that point. The second patient was referred 1 month after shunting with tense fontanel and vomiting. New brain imaging confirmed the whole shunt inside both lateral ventricles. The possible mechanisms causing this very uncommon complication and the management are explained.

Introduction

The most common treatment of hydrocephalus is ventriculo-peritoneal (VP) shunting.[1] Shunt failure due to infection and obstruction are frequent complications that occur in 40% - 70% of cases.[2] Migration of distal or proximal tube is a very uncommon event. Ventriculo-peritoneal shunt migration to mouth, thorax, transdiaphragmatic, heart, pulmonary artery, breast, stomach, gallbladder, liver, umbilicus, colon, inguinal hernia sac, bladder, vagina, anus, and scrotum have been reported in the literature.[1-5] Here, we report two infants with hydrocephalus and history of shunt insertion who presented with proximal and distal catheter migration and coiling inside the subcutaneous fluid collection in the first child and intraventricular in the second child. The possible pathophysiology and treatment are discussed.

Case Reports

Case 1

The patient is an 18 month old girl who presented with progressive swelling of scalp around the proximal incision of her previous shunt surgery. She was shunted 3 months ago due to congenital hydrocephalus and an enlarged head. In the second postoperative week, she found subgaleal swelling beneath the proximal incision without features of intracranial hypertension. The swelling was progressive and became associated with a wide and tense fontanel and persistent vomiting for 2 weeks prior to admission. On physical examination there was a wide and tense fontanel with setting sun sign. There was a tense subcutaneous swelling under the proximal incision that was extending to the neck measuring 8 × 5 cm without any fluid leakage. Skull radiographs showed the whole length of the peritoneal catheter pulled out from the peritoneal cavity and coiled subcutaneously [Figure 1a].

Figure 1

Skull X-ray confirms loop formation of distal catheter inside the subcutaneous pocket made by CSF collection beneath the scalp incision (a). Brain CT scan reveals hydrocephalus and big subgaleal fluid collection containing coiled shunt system (b)

A brain computed tomography (CT) scan confirmed coiling of the peritoneal catheter, which had migrated into the subgaleal swelling area. The proximal catheter was also not evident inside the ventricle [Figure 1b]. The proximal incision was opened and the whole shunt was found coiled up in the subcutaneous plane. The opening where the proximal catheter had entered the brain was found and sealed by suturing connective tissue to prevent fluid leakage from the hole. Proximal catheter was inserted through a new hole, and the distal part of shunt system was repositioned inside the abdomen using the original opening. The postoperative period was unremarkable, and all symptoms recovered completely. She is symptom-free during 1 year follow up.

Case 2

The patient is a known case of posthemorrhagic hydrocephalus subsequent to prematurity who was shunted at the age of 2 months. The shunt was complicated with infection after 2 months. He was reshunted 3 weeks later following removal of the infected VP shunt and appropriate antibiotic therapy. He was discharged with a well-functioning shunt, but referred 1 month later with tense fontanel and vomiting. A new brain CT scan confirmed the whole shunt system inside both lateral ventricles [Figure 2]. He was managed with endoscopic removal of whole shunt and then repositioning the VP shunt. The flushing device and the pump were fixed to the peri-cranium with suturing in order to prevent migration. His symptoms recovered completely. The patient is doing well after 6 months without any new complications.

Figure 2

Lateral view of skull shows shunt coiling inside the cranium (a). Axial view of brain CT scan reveals shunt migration inside both lateral ventricles (b)

Discussion

Ventriculo-peritoneal shunting is the most frequent method used for CSF diversion. Shunt malfunction due to migration is an uncommon complication. Peritoneal catheter migration may be the result of abdominal wall contractions driving out the catheter into the fibrous tract around it. This event can be subsequent to high intra-abdominal pressure or due to anchoring to a calcified point around the tube causing migration of the catheter towards subcutaneous tissue. Vigorous movements of head and neck (rotation or flexion-extension) can assist upward migration of peritoneal catheter too.[134] As the coiled form of catheter is comparable to the shunt packed in the box, retained memory of the shunt system can be another hypothesis for coiling.[25] Moreover, in the first patient, subgaleal CSF collection associated with wide space around the catheter at the entering point of shunt to the ventricle can make a place for sucking the catheter from the ventricle to the subcutaneous space. Fluid collection with dissecting the subcutaneous space around the catheter facilitates the smooth movement of catheter in its dilated tract and predisposes catheter migration to this place with the help of other proposed mechanisms mentioned before.

Conclusion

Catheter migration as a rare complication of shunt may be the result of abdominal wall contractions, increased intra-abdominal pressure, tube anchoring to a calcified point, strong head and neck movements, and finally the retained memory of shunt tube. Subgaleal swelling may represent another explanation causing this event.