Small-bowel obstruction causedby knotting of a peritonealshunt catheter is an extremely

rare complication of a ventriculoperi-toneal (VP) shunt. To date, only 4cases have been reported in the litera-ture.1–3 Though rare, small-bowel ob-struction by a VP shunt is an extremelyserious complication, which frequentlyleads to laparotomy and bowel resec-tion. Knotting of a peritoneal catheterdoes not occur spontaneously. Eachreported case involved attempted re-moval or revision of the shunt. We re-

port a case in which difficulty remov-ing the peritoneal catheter was fol-lowed by small-bowel obstruction dueto constriction of the small bowel in aloop of catheter.

CASE REPORT

A female infant with Dandy–Walkersyndrome underwent placement of aVP shunt 1 week after birth. She wasadmitted to hospital 7 weeks later withan obvious cellulitis around the shunttubing under her scalp. A culture of

the cerebrospinal fluid (CSF) from aVP shunt valve tap grew Staphylococcusaureus. The infant’s fontanelle was softand there was no Parinaud syndromeor papilledema to suggest shunt block-age. An antibiotic (vancomycin) wasgiven, and removal of the shunt was at-tempted. Adherence of a normallyplaced VP shunt 7 weeks after inser-tion is unusual, so operative prepara-tion and draping of only the retro -auricular incision was made. Duringwithdrawal of the peritoneal portion ofthe shunt, resistance was encountered,

Case ReportÉtude de cas

VENTRICULOPERITONEAL SHUNT KNOT: A RARE CAUSEOF BOWEL OBSTRUCTION AND ISCHEMIA

Yves Starreveld, MD; Dan Poenaru, MD; Peter Ellis, MD, MSc

From the Department of Surgery, Queen’s University, Kingston, Ont.

Accepted for publication Feb. 19, 1998

Correspondence to: Dr. Dan Poenaru, Kingston General Hospital, 76 Stuart St., Kingston ON K7L 2V7; tel. 613 549-6666 x3535, dp6@post.queensu.ca

© 1998 Canadian Medical Association (text and abstract/résumé)

Small-bowel obstruction caused by knotting of a peritoneal shunt catheter is an extremely rare and severecomplication of a ventriculoperitoneal (VP) shunt. In the 1-week-old female infant reported here who hada VP shunt, inability to remove the peritoneal catheter was followed by small-bowel obstruction and necro-sis due to intestinal strangulation in a tight loop of the catheter. An uncomplicated primary resection of thenecrotic segment was followed by placement of a temporary ventriculoatrial shunt. The authors suggestthat when withdrawal of the peritoneal part of a VP shunt meets with resistance, an intraoperative radi-ograph should be obtained to assess the position of the remaining catheter. If knotting is observed, an at-tempt to straighten the catheter with a guide wire is worthwhile. Should this fail, immediate laparoscopy orlaparotomy is indicated.

L’occlusion de l’intestin grêle provoquée par la formation d’un nœud dans un cathéter péritonéal de déri-vation représente une complication extrêmement rare et grave d’une dérivation ventriculo-péritonéale(VP). Dans le cas décrit ici d’un nouveau-né de sexe féminin âgé d’une semaine qui a subi une dérivationVP, l’incapacité d’enlever le cathéter péritonéal a été suivie d’une occlusion de l’intestin grêle et d’unenécrose attribuable à une strangulation intestinale survenue dans une boucle serrée du cathéter. Une résec-tion primaire sans complication du segment nécrosé a été suivie de la mise en place d’une dérivation ventriculo-auriculaire temporaire. Les auteurs indiquent que lorsque l’on rencontre une résistance pendantle retrait de la partie péritonéale d’une dérivation VP, il faudrait prendre une radiographie peropératoirepour révéler la position de la sonde qui reste. Si la radiographie révèle la présence d’un nœud, il vaut lapeine d’essayer de redresser le cathéter au moyen d’un fil guide. En cas d’échec, une laparoscopie ou la-parotomie immédiate est indiquée.

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and as a result, the peritoneal end wascut short and allowed to remain in theabdomen. Since the child had no evi-dence of peritonitis secondary to theCSF infection, we postponed removalof the peritoneal catheter pending clin-ical evolution of her condition. Post-operatively, the child became irritableand suffered episodes of bilious andsubsequently feculent vomiting.Abdominal radiography showed

evidence of acute bowel obstructionand a knot in the shunt catheter (Fig.1). At laparotomy, the peritonealcatheter was found knotted around aloop of bowel (Fig. 2). This 10-cmloop of small bowel was necrotic andwas resected with a primary end-to-end anastomosis. Under cover of in-travenously administered antibiotics,the infant was allowed to recover. Herhydrocephalus was managed with ser-ial ventricular taps. Eight days after re-section a ventriculoatrial shunt was in-serted. The shunt was then electivelyreplaced with another VP shunt.

DISCUSSION

Internal (CSF) infection of VPshunts is much more frequent inneonates than in older children. Al-though the management is still con-troversial, there is a strong trend tobetter cure rates and reduced chanceof bacterial ventriculitis sequelae withshunt removal and systemic antibiotictherapy.4 Because VP shunting is themost common pediatric neurosurgicalprocedure, revision or removal of in-fected shunts is a common problem.When the peritoneal end of thecatheter is removed, there is a slightchance that a loop of bowel will getcaught up in a tightening coil ofcatheter. This is felt as resistance dur-ing removal of the peritoneal end. Al-though this is only the fifth reportedoccurrence of small-bowel obstructioncaused by a knotted catheter, each oc-currence followed difficulty in remov-ing the peritoneal end of the catheter.It is remarkable that despite the com-

plexity of the involved structures, thefailure mode is very stereotyped. Inthe single cases reported by Murtagh,Quencer and Poole1 and Hlavin, Map-stone and Gauderer3 and the first casereported by Sanan and colleagues,2 thefinal picture of a shunt catheter knot-ted around a loop of small bowel wasidentical. All events occurred 24 to 48hours after an unsuccessful attempt atcatheter removal.We concur with the recommenda-

tions of Sanan and colleagues2 thatwhen there is difficulty in removingthe peritoneal catheter at operation,the position of the remaining cathetershould be assessed radiologically. Ifthere are any signs of knotting of theretained catheter, fluoroscopicallyguided straightening of the cathetermay be attempted with use of a guidewire, or the situation may be rectifiedby laparoscopy or laparotomy.

References

1. Murtagh FR, Quencer RM, Poole CA.Extracranial complications of cere-brospinal fluid shunt function in child-hood hydrocephalus. AJR 1980;135:763-6.

2. Sanan A, Haines SJ, Nyberg SL,Leonard AS. Knotted bowel: small-bowel obstruction from coiled peri-toneal shunt catheters. Report of twocases. J Neurosurg 1995;82:1062-4.

3. Hlavin ML, Mapstone TB, GaudererMW. Small bowel obstruction sec-ondary to incomplete removal of a ven-triculoperitoneal shunt: case report.Neurosurgery 1990;26:526-8.

4. Blount JP, Campbell JA, Haines SJ.Complications in ventricular cere-brospinal fluid shunting. NeurosurgClin North Am 1993;4:633-56.

STARREVELD, POENARU, ELLIS

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FIG. 1. Abdominal x-ray film shows knotted in-traperitoneal component of the ventriculoperi-toneal shunt.

FIG. 2. Intraoperatively, the VP shunt knot canbe seen strangulating loops of small bowel.

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