Shunt malfunction is still an existing problem for neurosurgeons and remains challenging despite the great progress in shunt technologies in the past decades.1,2,3 Shunt dysfunction may be caused by several factors most commonly obstruction of the ventricular catheter by choroid plexus.4
The repeated shunt malfunction after surgical revision provided a problem that led neurosurgeons to search alternative ways trying to avoid multiple shunt revisions which is associated with high incidence of complications like infection.5
Since the early 1990s, fiberoptic endoscopes became available for use in treating shunt related problems providing a safe and effective tool to reach the ventricular catheter and handle the problem in cases of shunt malfunction as well as providing a guide for shunt placement.6
Several endoscopic procedures had been postulated for dealing with shunt malfunction; ETV was reported to be an effective method in such cases with good outcome data.7,8,9 In addition, the endoscope provides efficient visualization of the ventricular system allowing cauterization or lysis of choroid or ependymal adhesions that may partially obstruct the tip of the ventricular catheter, as well as repositioning of the catheter’s tip in a proper site or passing it through a septostomy performed for unilateral ventricular dilatation.6,10
The aim of this study is to evaluate the efficacy, safety, and possible complications with endoscopic procedures in treating different types of shunt malfunction.
PATIENTS AND METHODS
This study is a retrospective study of prospectively collected data of 12 patients admitted to Department of Neurosurgery, Cairo University Hospitals between January 2006 and December 2008 was done.
Patient selection was based on; 1) all had posterior parietal V-P shunt placement for different causes of hydrocephalus, 2) all patients suffered shunt malfunction +/- malposition and had undergone shunt revision at least once with recurrence of symptoms, 3) all patients had CSF sampling via shunt tap, confirming them infection-free before endoscopic intervention.
Patients included 5 males, 7 females (M:F ratio 1:1.4) with age ranging from to 25 years (mean age 18 years). The time interval between shunt revision and endoscopic intervention ranged from 2-30 days (mean of 16 days).
All patients were assessed clinically and radiologically by CT and/or MRI of the brain, in addition to abdominal CT scan excluding any causes of distal shunt malfunctiuon.
All 12 patients were operated upon in Cairo University Hospitals by the author.
Seven patients (58%) were operated upon by ETV alone without dealing with the ventricular catheter. Under general anesthesia, the patient was placed in a supine position with the head flexed 10-15°. A burr hole was created on the coronal suture, 3 cm off the midline. A rigid 0° endoscope lens (Karl Storz, Gaab System, Germany) was introduced through its sheath after ventricular cannulation.
The floor of the 3rd ventricle was reached via the foramen of Monro, fenestration of the floor between the infundibulum and mamillary bodies was performed using gentle blunt pressure by the diathermy probe and Fogarty balloon dilatation. The prepontine cistern is then inspected ensuring clear CSF pathway.
Three patients (25%) were suffering from shunt malposition causing univentricular drainage. These patients were operated upon through a contralateral coronal burr hole performing septostomy by blunt and/or diathermy cauterization then the tip of the ventricular catheter was identified, grasped with a forceps and brought into the contralateral ventricle.
Two patients (17%) were shown to have proximal shunt occlusion by choroid and ependymal tissues. These patients had endoscopic identification of the occluded catheter’s tip, lysis of the obstructing tissues by diathermy coagulation and scissors until the catheter’s tip is completely free. Then, ETV was performed to help in CSF drainage in case of recurrence of adhesions.
Demographic data of patients, cause of hydrocephalus, procedure and complications are illustrated in Table (1). Patients were assessed both clinically and radiologically with 2nd day postoperative CT scans. Clinically, all 12 patients (100%) had marked improvement of symptoms of increased intracranial pressure within the first postoperative week.
Radiologically, ventricular size, position of the ventricular catheter and laxity of the subarachnoid spaces were assessed as follows; 7 patients (58%) had reduction of the ventricular size as measured by the largest width of both frontal horns in postoperative CT scan. All patients (100%) showed laxity of the preoperative effaced subarachnoid spaces, while good shunt position was confirmed in the 3 patients having catheter repositioning through septostomy.
Patients were followed up both clinically and radiologically in 3 months intervals for a period ranging from 12-48 months (mean of 24 months). Two patients (17%) had recurrence of symptoms within 2 and 3 weeks postoperative, shunt tap and CSF analysis proved ventriculitis. Both patients had shunt removal and EVD placement for 7 days and 12 days respectively until CSF infection cleared then shunt placement was reperformed.
One patient (8%) presented with recurrence of shunt malfunction 9 months after ETV, and was reoperated upon by endoscopic exploration showing adhesions partially obstructing the ostium of the 3rd ventricle, endoscopic fenestration of the ostium was performed. No procedure-related complications were encountered.
Figures (1) and (2) show illustrations of surgical procedures and neuroradiology of two of the patients included in the study.
Despite the great advances in shunt technologies, shunt malfunction remains to be a challenging problem to neurosurgeons.7
The risk of V-P shunt malfunction was reported to be 25-40% in the 1st year and 4-5% per year thereafter.1,11 Some authors postulated that 81% of shunts require revision after 12 years.4 Many factors may cause shunt malfunction most commonly the position of the ventricular catheter and choroid plexus adhesions occurring around its tip.12
Nowadays, the use of endoscopic techniques offered an excellent route for visualization of the ventricular system and the ventricular catheter facilitating management of shunt malfunction by various techniques.13
Endoscopic 3rd ventriculostomy (ETV) was reported to be an effective treatment in patients with obstructive hydrocephalus who had undergone previous shunt procedures.14,15 High success rates were published by many authors ranging from 42-100%. Boschert and coworkers7 in 2003 and Buxton et al.16 in 2001 reported 82% success rate in 17 patients each. Murshid17 in 2000 had 88.8% success rate in 9 patients while Cinalli and colleagues18 in 1998 reported 76.7% success rate in 30 patients all with long term follow up. All reported no complications associated with ETV and failure was often attributed to ventriculitis.
Other endoscopic procedures can be performed either alone or in combination with ETV, like lysis of adhesions around the ventricular catheter, fenestration of entrapped compartment, septostomy and shunt repositioning.19
In our study, ETV, lysis of adhesions, repositioning of shunt through septostomy were performed with comparable success rate in 9 patients (75%) to the previously mentioned publications. No procedure related complications were encountered and failure was established in 3 patients (25%), 2 of them suffered from ventriculitis and the 3rd had partial obliteration of the ETV 9 months later and the ostium was refenestrated. Failure rate was coinciding with published results in literature review as well as low rate of complications when performed by experienced hands.
Endoscopic procedures in experienced hands are safe and effective alternatives in treating V-P shunt malfunction and malposition with high success rate and few reported complications.
[Disclosure: Author reports no conflict of interest]
1. Drake JM, Kestle J, Milner R, Cinalli G, Boop F, Piatt J Jr, et al. Randomized trial of cerebrospinal fluid shunt valve design in pediatric hydrocephalus. Neurosurgery. 1998; 43: 294-305.
2. Hoppe-Hirsch E, Laroussinie F, Brunet L, Sainte-Rose C, Renier D, Cinalli G, et al. Late outcome of the surgical treatment of hydrocephalus. Childs Nerv Syst. 1998; 14: 97-9.
3. Kestle J, Drake J, Milner R, Sainte-Rose C, Cinalli G, Boop F, et al. Long-term follow-up data from the Shunt Design Trial. Pediatr Neurosurg. 2000; 33: 230-6.
4. Sainte-Rose C, Piatt JH, Renier D, Pierre-Kahn A, Hirsch JF, Hoffmann HJ, et al. Mechanical complications in shunts. Pediatr Neurosurg. 1991; 17: 2-9.
5. Pettorini BL, Frassanito P, Tamburrini G, Massimi L, Caldarelli M, Di Rocco C. Retrieval of ventricular catheter with the aid of endoscopy. J Neurosurg pediatrics. 2008; 2:71-4.
6. Walker ML, MacDonald J, Wright LC. The history of ventriculoscopy: where do we go from here?. Pediatr Neurosurg. 1992; 18: 218-23.
7. Boschert J, Hellwig D, Krauss JK. Endoscopic third ventriculostomy for shunt dysfunction in occlusive hydrocephalus: long-term follow up and review. J Neurosurg. 2003; 98: 1032-9.
8. Cinalli G. Alternatives to shunting. Childs Nerv Syst. 1999; 15: 718-31.
9. Mallucci CL, Buxton N, Vloeberghs M, Punt J. Neuroendoscopic third ventriculostomy. the first line of treatment for blocked ventriculoperitoneal shunts? (Abstract). Eur J Pediatr Surg. 1997; 7 (Suppl 1): 65.
10. Schroeder HW, Oertel J, Gaab MR. Endoscopic treatment of cerebrospinal fluid pathway obstructions. Neurosurgery. 2007; 60 (2 Suppl): 44-52.
11. Piatt JH Jr, Carlson CV. A search for determinants of cerebrospinal fluid shunt survival: retrospective analysis of a 14-year institutional experience. Pediatr Neurosurg. 1993; 19: 233-42.
12. Tuli S, O’Hayon B, Drake J, Clarke M, Kestle J. Change in ventricular size and effect of ventricular catheter placement in pediatric patients with shunted hydrocephalus. Neurosurgery. 1999; 45: 1329-35.
13. Lewis AI, Keiper GL Jr, Crone KR. Endoscopic treatment of loculated hydrocephalus. J Neurosurg. 1995; 82: 780-5.
14. O’Brien DF, Javadpour M, Collins DR, Spennato P, Mallucci CL. Endoscopic third ventriculostomy: an outcome analysis of primary cases and procedures performed after ventriculoperitoneal shunt malfunction. J Neurosurg. 2005; 103 (5 Suppl Pediatrics): 393-400.
15. Tisell M, Almstrom O, Stephensen H, Tullberg M, Wikkelso C. How effective is endoscopic third ventriculostomy in treating adult hydrocephalus caused by primary aqueductal stenosis?. Neurosurgery. 2000; 46: 104-11.
16. Buxton N, Ho KJ, Macarthur D, Vloeberghs M, Punt J, Robertson I. Neuroendoscopic third ventriculostomy for hydrocephalus in adults: report of a single unit’s experience with 63 cases. Surg Neurol. 2001; 55: 74-8.
17. Murshid WR. Endoscopic third ventriculostomy: towards more indications for the treatment of non-communicating hydrocephalus. Minim Invasive Neurosurg. 2000; 43: 75-82.
18. Cinalli G, Salazar C, Mallucci C, Yada JZ, Zerah M, Sainte-Rose C. The role of endoscopic third ventriculostomy in the management of shunt malfunction. Neurosurgery. 1998; 43: 1323-9.
19. Oi S, Abbott R. Loculated ventricles and isolated compartments in hydrocephalus: their pathophysiology and the efficacy of neuroendoscopic surgery. Neurosurg Clin N Am. 2004; 15: 77-87.
20. Schroeder HW, Niendorf WR, Gaab MR. Complications of endoscopic third ventriculostomy. J Neurosurg. 2002; 96: 1032-40.