Infusion technique can be used to distinguish between dysfunction of a hydrocephalus shunt system and a progressive dementia

Abstract

In a deteriorating shunted patient with hydrocephalus, an investigation of shunt function is often performed to distinguish a dysfunctioning shunt from an aggravated condition of the disease. The paper illustrates how a lumbar cerebrospinal fluid (CSF) infusion method can be used to evaluate post-operative deterioration in a shunted patient in order to give the physician valuable support in the shunt revision decision. A 77-year-old man with hydrocephalus was treated operatively by the insertion of a CSF shunt. Owing to shunt failure, the shunt was revised twice during a 5 year period. Using a computerised infusion technique method, with two needles placed in the lumbar subarachnoid space, the CSF dynamic system was determined pre- and post-operatively with the functioning as well as the dysfunctioning shunts. The data were verified with a bench-test of the extirpated CSF shunt. There was a significant difference in conductance G between CSF systems with an open shunt and CSF systems with no shunt or an occluded shunt (deltaG= 38 mm3 s(-1) kPa(-1), p = 0.014, n= 7, ANOVA). CSF dynamics investigations, with and without a shunt, can give valuable clinical support in the management of a deteriorating hydrocephalus patient. With further development of the lumbar infusion method moving towards easy-to-use equipment, there is potential for widespread clinical use.

Assessment of cerebrospinal fluid outflow resistance

“…At 36 months G out was reduced to 25 ll/s/kPa (R out = 5.0 mm Hg/ml/ min) indicating partial block, and there was a tendency to flow a low P IC suggesting that the valve did not close. (Figure modified from [26) constant pressure level should equal the formation rate. Knowledge of formation rate, together with R out and P r , offers the possibility of calculating P d [27].…”

“…Furthermore, by examining the full flow-pressure curve (Fig. 12), possible over-drainage due to a nonclosing valve can also be disclosed [26].…”

“…The use of infusion tests to assess shunt function in vivo has been highlighted [22,26,46,50,72]. When considered in conjunction with the hydrodynamic properties of hydrocephalus shunts and the preoperative values of the patient, the test provides a valuable method for the assessment of shunt function in vivo.…”

Paraplegia caused by invasive spinal aspergillosis

“…Importantly, CSF infusion did not cause misreading of ICP LS , a prerequisite when determining CSF outflow resistance via lumbar space in the course of diagnosing INPH 6 and evaluating shunts. 7 The determination coefficient of 0.996 and slope of 0.98 suggest that changes in brain tissue pressure are equally well recognized via lumbar space, an obligation for viable ICP detection by lumbar puncture. In the INPH-associated pressure range, 6 the patient-dependent factors (table) can be interpreted as the horizontal individual mean differences between ICP LS and ICP BT .…”

Continuous intracranial pressure monitoring via the shunt reservoir to assess suspected shunt malfunction in adults with hydrocephalus

“…7,12 This method, which is virtually identical to the technique used to assess outflow resistance for the initial diagnosis of NPH, entails a lumbar puncture with two needles and requires special expertise and equipment that is not widely available. Another limitation of this method is that it cannot demonstrate whether intracranial hypotension (siphoning) is present.…”