Use of CSF infusion studies to unblock occluded hydrocephalus ventricular shunt catheters: a preliminary report of two patients

Abstract

Two patients with ventriculoperitoneal shunts presented with symptoms of raised intracranial pressure indicative of possible shunt malfunction. During investigation, to eliminate this possibility, cerebral spinal fluid infusion studies were performed, which indicated proximal occlusion of the shunts in both cases. Retrograde flush of the ventricular catheter was performed during temporary compression of the siphon-control device, a manoeuvre which blocks distal flow. After the use of this technique, both patients' symptoms improved and they have remained symptom-free for over 2 years. This case report validates the role that infusion studies can play in clearing a blocked ventricular catheter shunt.

CSF Dynamics for Shunt Prognostication and Revision in Normal Pressure Hydrocephalus

“…CSF infusion tests, the procedure, data recording, analysis, and interpretation have been exhaustively detailed in numerous publications and do not fall within the scope of this review [ 2 , 4 , 5 , 9 , 39 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ]. A comprehensive summary of the meaning and clinical significance of each parameter will be briefly described in the relevant sections.…”

“…Besides their short duration (average 45 min for infusion tests compared to an average of 2-day hospital stays that involve a general anesthetic and more complications for ICP monitoring), they allow for calculation of resistance to CSF outflow (Rout) and elasticity. Several shunt problems can also be better investigated and diagnosed with infusion test [ 39 , 43 , 57 , 58 , 59 ]. Less commonly, we have described the opportunity to flush shunts during infusion tests and clear any obstructions usually associated with the intraventricular catheter [ 57 ].…”

“…Considering all of the above, concluding who requires a revision and who does not, using CSF dynamics appears an easier question to answer than when to implant a shunt in the first place. Consequently, we have been able to address this question in a clinical as well as a theoretical context and have shown the feasibility and safety of shunt infusion tests both in paediatric and in adult patients with non-acute hydrocephalus [ 39 , 40 , 43 , 57 ]. Additionally, we have reported and discussed the benefits conveyed to patients and to healthcare systems through objective shunt testing, averaging at least 2 quality years away from hospitals and neurosurgical tables and around 1 million GBP annually respectively [ 39 ].…”

Shunt infusion studies: impact on patient outcome, including health economics

“…In addition, measurements of steady-state ICP cannot exclude shunt malfunction. No flow through a shunt does not automatically mean obstruction, but many other things, including inadequate pressure to open the valve or even collapsed ventricles (slit ventricles) around the proximal catheter, among others [4,6,10,23,28,29,32,43]. Last but not least, our current protocol for performing shunt infusion studies that includes strict aseptic technique and proper cleaning and disinfection appears to be 100% effective in avoiding additional costs related to infections from the procedure.…”

“…Another aspect considered in the revision costs, is that the comprehensive nature of infusion studies allows the clinical team to be aware, and not blinded to, the location of the shunt issue. A proximal catheter obstruction can easily be differentiated from a valve or distal catheter problem [6,7,10,11,23,26,28,32,38]. This most probably decreases the cost of the revision surgery, since parts of the shunt can be left intact, decreasing surgical time, use of equipment, complications and postoperative hospital stay.…”