Extrusion of a Peritoneal Catheter of a Ventriculoperitoneal Shunt from the Urethra
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.310094
Source of Support: None, Conflict of Interest: None
Ventriculoperitoneal (VP) shunt placement is one of the common neurosurgical procedures performed for the management of hydrocephalus., The complication rate associated with this procedure is approximately 24–47%, and includes infection, shunt tube obstruction, pseudocysts formation, bowel perforation, and shunt migration., Extrusion of a shunt catheter may occur through any natural orifice, most commonly is the anus (61.9%) followed by per-oral and urethral. Cases with peroral extrusion are very rare and are associated with gastric perforation., In literature, about 20 cases of bladder perforation by a peritoneal catheter have been reported. In only 12 cases, the catheter has protruded through the urethra.,,,,,,,,,,, Herein, we report a case of a 7-month-old female child in whom VP shunt was placed for obstructive hydrocephalus due to a posterior fossa tumor. After 6 months of the procedure, the mother noticed that the shunt tube was coming out of the urethra and hence she brought the child to the hospital for further evaluation [Figure 1]. On examination, the baby was conscious and had a normal temperature. There were no signs of infection, meningeal irritation, or neurological deficit. The abdominal examination was normal. Shunt series confirmed the integrity of the shunt; however, it also showed that the tube was traversing outside through urethra [Figure 2]. The peritoneal catheter was divided through an abdominal incision, after which the distal part was extracted downward from the urethra, while the proximal part was extracted upward from a scalp incision. Antibiotic treatment was administered for two weeks, and a new VP shunt was inserted in a second-stage surgery. The postoperative course was uneventful and the patient was discharged. At follow-up, additional surgery was performed to excise the posterior fossa tumor.
The extrusion of the shunt catheter through the urethra is a rare complication with only a few reported cases [Table 1].,,,,,,,,,,,
The urinary system is located in the extra-retroperitoneal space. It is unusual to observe the intraperitoneal catheter of the VP shunt passing through the peritoneum and reaching the bladder wall.
Theories have been suggested for its mechanism. Prasad et al. were the first to report and explain the mechanism after analysis of previous case reports. He postulated a series of events as follows: fixation of the tube to the viscera, followed by penetration, perforation, and then entry into the urethra, and finally extrusion.
Udea et al. reported a late organic perforation of a peritoneal catheter of the urinary bladder with extrusion through the urethra in an 82-year-old woman ten years after her shunt surgery.
In 2002, two pediatric cases were reported with extrusion of the shunt tube from the anus and urethra without a clear explanation. Later, Aguiar et al. described the mechanism suggested by Prasad et al. He added that the anchoring of the shunt tube to the urinary bladder provokes an intense inflammatory reaction that, in turn, results in local erosion, after which the peristaltic movement of the viscera can expel the tube further distally. Besides, cerebrospinal fluid (CSF) pulsations and increased intra-abdominal pressure occur, which aid in perforation and further the movement of the shunt tube.
Pohlman et al. reported an additional theory. The fibrous encasement occurs at the site of adherence of the tube to the wall of the bladder. Later, repeated pressure from the mechanical forces of adjacent structures stimulates the perforation of the wall of the bladder. Furthermore, allergy to the silicon tube could provoke an inflammatory reaction that causes perforation and necrosis. It was the first to highlight the impact of the shunt tube material.
Chen et al. reported a patient who developed recurrent urinary tract infections at six months after VP shunt surgery. He explained that urethral extrusion was due to a rigid tip and the long distance of the peritoneal tube within the abdomen.
Yazar et al. added that the Valsalva manoeuvre during the respiratory cycle could explain the expulsion of a distal shunt tube. They suggested a future study with an animal model to clearly define the cause.
Kataria et al. proposed that when the shunt tube was in a moist environment and had CSF flowing through it, perforation was not possible. When the blockage of CSF flow occurred, the surface of the tube became dry and adhered to the wall of the viscera. This adherence would begin the penetration of the wall of the urinary bladder. Besides, the tube itself, such as calcification of the tip and the adhesive nature of silicon my play role.
Recently, two cases of 29-year-old male patients have been reported. In the first case, migration of the shunt tube to the urethral and rectal orifices occurred. In the second case, the long shunt tube was extruded from the penile urethra. Surgery with laparoscopic visualization was performed to insert a new tube, which was fixed to the suprahepatic recess.
We explain that the absorptive capacity of the peritoneum may decrease over time, and the accumulated CSF within the abdominal cavity exerts a pressure force on the weakest point of the peritoneum and the adherent viscera. Perforation at this site depends on the site of CSF accumulation due to gravity and the most preferred position of the patient.
Patient management should include antibiotic administration, radiological evaluation, urological consultation, and preparation for surgical intervention. Surgical options include shunt removal in the manner that we described. The urologist can decide whether to repair the urinary bladder. In our case, the urologist decided against repair. The insertion of a new VP shunt was advised to be delayed until no evidence of infection or meningitis was present. Shunt externalization is an option when a known shunt-dependent patient has a risk of infection from such complications.
In summary, peritoneal extrusion is an extremely rare complication of VP shunt placement and should be appropriately managed to avoid further complications, especially in patients with a posterior fossa tumor. Frequent follow-up by pediatric neurosurgeons and increased awareness of parents of rare complications of VP shunts are advised.
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[Figure 1], [Figure 2]