Key-words:
Abdominal wall - cerebrospinal fluid - extrusion - shunt independent - ventriculoperitoneal
shunt
Introduction
Ventriculoperitoneal shunt (VP-shunt) is one of the most frequently performed procedures
for the management of hydrocephalus. However, various complications can be related
to proximal and distal ends of the shunt with complications at the distal end occurring
more frequently. Distal abdominal complications may include disconnection, obstruction,
peritonitis, pseudocyst formation, hydroceles, and catheter migration.[[1]] The reported incidence of distal VP-shunt migration is around 10% of all VP-shunt
complications.[[2]] Spontaneous extrusion of the distal end of the VP-shunt through intact abdominal
wall is very rare and only few cases have been reported in the literature.[[1]],[[3]],[[4]],[[5]],[[6]],[[7]] According to our institute's records, for more than 36 years' experience, there
were not any recorded cases of distal VP-shunt migration through abdominal wall; except
for 1 thoracic, 2 anal, 1 vaginal, and 1 pseudocyst.[[8]],[[9]],[[10]],[[11]] This study reports a case of extrusion of distal VP-shunt through intact abdominal
wall and what is special about the case is that the patient remained asymptomatic
and shunt independent. The aim of this report is to draw the attention toward the
possibility of such complication and the importance to assess the future need for
long-term cerebrospinal fluid (CSF) diversion.
Case Report
An 11-year-old Saudi boy who presented to the hospital with spontaneous extrusion
of the distal end of VP-shunt through the intact abdominal wall. The patient was in
his usual state of health until 2 weeks prior to his presentation when he developed
right abdominal wall patchy redness with localized swelling and drops of fluid coming
out of it. The patient was born on the 6th month of gestation. He is a known case
of congenital hydrocephalous, cerebral palsy, and seizure since birth. He was managed
since then with a VP-shunt, with no history of revision. On examination, the patient
was conscious, vitally stable, and had normal body built. The extruded peritoneal
end of VP-shunt was on the right side of the abdomen away from the previous surgical
incision with inflammation, erythema, tenderness, and discharge around it suggesting
infection.
Laboratory findings were within normal levels and the CSF culture was negative. Abdominal
computed tomography (CT) and showed the peritoneal end tube of VP-shunt penetrating
along the right side of the abdominal wall [[Figure 1]]c and [[Figure 1]]d. Head CT was compared to the CT made 2 years ago, showed no significant changes
in size of the lateral ventricles with re-demonstration of the left lateral ventricle
dilation [[Figure 1]]a.
Figure 1: (a) Preoperative coronal head computed tomography showing the proximal end of ventriculoperitoneal-shunt
placed in the right lateral ventricle. (b) Postoperative coronal head computed tomography
after removing of the ventriculoperitoneal shunt. (c and d) Preoperative sagittal
and transversal abdominal computed tomography showing the distal tip of ventriculoperitoneal
shunt protruding through the right anterior abdominal wall
Broad-spectrum antibiotics were started. Abdominal externalization was done for the
patient and kept under observation for few days, no CSF output was there and he was
asymptomatic. Hence, we disconnected the proximal end of the VP-shunt distal to the
valve in the neck and pulled out the extruded peritoneal end through the abdominal
wall. A postoperative head CT [[Figure 1]]b showed no dilation of the size of the ventricles and the patient was discharged
after 1 week. The patient was followed up for more than 4 years with no complications.
Discussion
The exact cause of VP-shunt extrusion cannot yet be determined. However, various hypotheses
have been proposed. Akyüz et al.[[12]] hypothesized that it may occur due to adherence of the distal end of the catheter
to a viscera or body wall, a local inflammatory response weakens that area, and the
distal end of the catheter will gradually erode through it. Borkar et al.[[13]] suggested that it could be related to focal wound dehiscence, ischemic necrosis
of dermis, poor host immunity, allergic reactions to shunt components or factors related
to surgical technique. Other factors that have been postulated by some authors are;
the patient's age, malnutrition, stiff catheter, overlength of the catheter, and use
of trocar.[[5]],[[6]],[[12]] Additional contributing factors by Chugh et al.,[[6]] are intestinal peristalsis, intra-abdominal pressure, presence of congenital hernial
sac, long-term use of steroids that lead to fragile skin and water hammer effect of
the pulsation of the CSF. We suggest that the cause in this case could be attributed
to the continuous hammer effect of the CSF pulsations that eroded the abdominal wall,
caused local inflammation, and then extruded through the skin.
When spontaneous extrusion of the distal end of a VP-shunt through the abdominal wall
is encountered, a course of prophylactic antibiotics should be started immediately
and the shunt system must be removed completely. During removal of the extruded shunt
system, it is important to avoid pulling the distal end proximally to prevent the
spread of infection from the extrusion site. After complete removal of the existing
shunt system, a sufficient recovery gap is then allowed so that the CSF culture is
negative on two successive occasions. In the meantime, CSF can be drained by external
ventricular drain if there are signs of increased intracranial pressure. Simultaneously,
the patient is assessed for the requirement of CSF diversion with serial clinical
and radiological examinations. If subsequent CSF diversion is required, endoscopic
third ventriculostomy or replacement of shunt system on the opposite side can be performed.
In addition, strict follow-up should be performed for serial CSF cultures and in order
to ensure correct functioning of the new shunt system.[[1]],[[6]],[[14]] In this case, the patient was managed similarly, but he did not require a subsequent
replacement of the shunt. A possible reason for him to be shunt independent, is that
he had the initial shunt before the maturation of the CSF circulation, but then the
pathways have opened up and were functioning independently from the placed shunt.[[15]]
Conclusion
VP-shunt extrusion through abdominal wall is a rare complication. The exact cause
is still not known, but the suggested cause in this case could be attributed to the
continuous hammer effect of the CSF pulsations. If such complication is encountered,
the basic management should include prophylactic antibiotics, complete removal of
VP-shunt, adequate recovery gap so that the CSF culture is negative in two successive
occasions, followed by replacement of shunt system on opposite side. However, in this
case, the patient did not require reinsertion of a new shunt system as he was shunt
independent.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
In the form, the patient has given his consent for his images and other clinical information
to be reported in the journal. The patient understands that his name and initial will
not be published and due efforts will be made to conceal his identity, but anonymity
cannot be guaranteed.
