Ernst J. Delwel

Dutch normal pressure hydrocephalus study: baseline characteristics with emphasis on clinical findings

We present the baseline characteristics of 101 patients with normal pressure hydrocephalus (NPH), entering a study that evaluates the diagnostic reliability of CSF outflow resistance. Patients were assessed by a gait scale consisting of 10 features of walking and the number of steps and seconds necessary for 10 m, a dementia scale comprising the 10 word test, trail making, digit span and finger tapping, the modified Mini Mental State Examination (3MSE) and the modified Rankin scale (MRS). Inclusion criteria were a gait and dementia scale ≥ 12 (range 2–40), a MRS ≥ 2 and a communicating hydrocephalus on CT. Gait disorder and dementia varied from mild to severe leading to MRS 2 in 17%, MRS 3 in 34%, MRS 4 in 21%, MRS 5 in 16% and MRS 6, including akinetic mutism, in 12%. Only one patient showed both normal tandem walking and turning. Small steps, reduced foot floor clearance and wide base were also frequently seen in the 67 patients walking independently; 34 needed assistance or could not walk at all. Applying the 3MSE, 64% were demented; the remaining 36% exhibited a milder cognitive deficit. The 10 word test and trail making decreased with increasing dementia. Digit span and finger tapping declined in the most demented patients. This group of elderly patients with NPH, mostly of the idiopathic type, proved to be vulnerable because of considerable disability and comorbidity.

Does CSF Outflow Resistance Predict the Response to Shunting in Patients with Normal Pressure Hydrocephalus

The value of the measurements of CSF outflow resistance (Rcsf) relative to predicting outcome after shunting was studied. In a group of 101 patients with mainly idiopathic normal pressure hydrocephalus (NPH) Rcsf was obtained by lumbar constant flow infusion. Gait disturbance and dementia were quantified using an NPH scale (NPHS) and disability by the Modified Rankin scale (MRS). Patients were assessed before and at 1, 3, 6, 9 and 12 months after surgery. Outcome measures were differences between the preoperative and last NPHS and MRS scores. Improvement was defined as a change of > or = 15% in NPHS and > or = 1 grade in MRS. Intention-to-treat analysis of all patients at one year yielded improvement of 57% in NPHS and 59% in MRS. Efficacy analysis, excluding comorbidity unrelated to NPH, revealed positive predictive values of around 80% at Rcsf < 18, and between 90% and 100% at Rcsf > or = 18 mm Hg/ml/min. For Rcsf > or = 18, the likelihood ratios were also higher. We conclude that the best predictor of the response to shunting is an Rcsf > or = 18 mm Hg/ml/min. Since two-thirds of the patients with Rcsf < 18 showed improvement as well, these patients should not be denied shunting.

The prognostic value of clinical characteristics and parameters of cerebrospinal fluid hydrodynamics in shunting for idiopathic normal pressure hydrocephalus

BACKGROUND It is difficult to predict which patients with symptoms and radiological signs of normal pressure hydrocephalus (NPH) will benefit from a shunting procedure and which patients will not. Risk of this procedure is also higher in patients with NPH than in the overall population of hydrocephalic patients. The aim of this study is to investigate which clinical characteristics, CT parameters and parameters of cerebrospinal fluid dynamics could predict improvement after shunting. METHODS Eighty-three consecutive patients with symptoms and radiological signs of NPH were included in a prospective study. Parameters of the cerebrospinal fluid dynamics were measured by calculation of computerised data obtained by a constant-flow lumbar infusion test. Sixty-six patients considered candidates for surgery were treated with a medium-pressure Spitz-Holter valve; in seventeen patients a shunting procedure was not considered indicated. Clinical and radiological follow-up was performed for at least one year postoperatively. FINDINGS The odds ratio, the sensitivity and specificity as well as the positive and negative predictive value of individual and combinations of measured parameters did not show a statistically significant relation to clinical improvement after shunting. CONCLUSIONS We conclude that neither individual parameters nor combinations of measured parameters show any statistically significant relation to clinical improvement following shunting procedures in patients suspected of NPH. We suggest restricting the term normal pressure hydrocephalus to cases that improve after shunting and using the term normal pressure hydrocephalus syndrome for patients suspected of NPH and for patients not improving after implantation of a proven well-functioning shunt.

Cerebral hemodynamics before and after shunting in normal pressure hydrocephalus

Objective– To study the relationship between cerebral hemodynamics and clinical performance in normal pressure hydrocephalus (NPH), before and after surgery. Material and methods – Ten patients were studied prospectively before and 3 months after shunt surgery by means of transcranial Doppler (TCD). Clinical performance was scored by means of an NPH scale and the modified Rankin scale. Results– Peak systolic and mean cerebral blood flow velocity (MCV) were lower and cerebrovascular CO2 reactivity was higher after shunt surgery. The three patients with clinical improvement had higher preoperative end diastolic cerebral blood flow velocity and MCV. All postoperative cerebral blood flow velocities were higher in patients with clinical improvement. Conclusion– Our data suggest that higher cerebral blood flow velocity before surgery in patients with NPH is related to clinical improvement after shunt surgery. Cerebral hemodynamic parameters may develop into predictors of successful shunt surgery in patients with normal pressure hydrocephalus.

A randomised trial of high and low pressure level settings on an adjustable ventriculoperitoneal shunt valve for idiopathic normal pressure hydrocephalus: results of the Dutch evaluation programme Strata shunt (DEPSS) trial

Background In treating idiopathic normal pressure hydrocephalus (INPH) with a shunt there is always a risk of underdrainage or overdrainage. The hypothesis is tested whether patients treated using an adjustable valve preset at the highest opening pressure leads to comparable good clinical results with less subdural effusions than in a control group with an opening pressure preset at a low pressure level. Methods A multicentre prospective randomised trial was performed on a total of 58 patients suspected of INPH. Thirty patients were assigned to (control) group 1 and received a Strata shunt (Medtronic, Goleta, USA) with the valve preset at a performance level (PL) of 1.0, while 28 patients were assigned to group 2 and received a Strata shunt with the valve preset at PL 2.5. In this group the PL was allowed to be lowered until improvement or radiological signs of overdrainage were met. Results Significantly more subdural effusions were observed in the improved patients of group 1. There was no statistically significant difference in improvement between both groups overall. Conclusions On the basis of this multicentre prospective randomised trial it is to be recommended to treat patients with INPH with a shunt with an adjustable valve, preset at the highest opening pressure and lowered until clinical improvement or radiological signs of overdrainage occur although slower improvement and more shunt adjustments might be the consequence.

The First Description of a Device for Repeated External Ventricular Drainage in the Treatment of Congenital Hydrocephalus, Invented in 1744 by Claude-Nicolas Le Cat

An 18th century report of a device for repeated extracranial drainage of cerebrospinal fluid in the treatment of congenital hydrocephalus is reviewed. On 15th October 1744, the French surgeon Claude-Nicolas Le Cat (1700–1768) introduced a specially invented canula into the lateral ventricle of a newborn boy with hydrocephalus. The canula was used as a tap and was left in place for 5 days, until the death of the child. This procedure should be seen as the first documented description of a device for repeated ventricular taps in the treatment of hydrocephalus.

CAVERNOUS HEMANGIOMA OF THE MESENCEPHALON: TONSILLOUVEAL TRANSAQUEDUCTAL APPROACH. Commentary

OBJECTIVE Recent advances in microsurgical techniques facilitate surgical resection of brainstem lesions that were previously considered inoperable. In this article we present, for the first time, the tonsillouveal transaqueductal approach to access a progressively symptomatic cavernoma within the depth of the tegmentum of the mesencephalon. METHODS A 52-year-old woman presented with a history of slowly progressive right-sided hemiparesis and ataxia. On magnetic resonance imaging, a relatively large cavernoma involving the tegmentum of the mesencephalon was shown. The sylvian aqueduct was patent and there was no secondary ventriculomegaly. The patient underwent surgery via a suboccipital craniotomy and C1 laminectomy. The right tonsillouveal and medullotonsillar spaces were opened to the level of the choroidal point of the posteroinferior cerebellar artery. The tela choroidea was incised from the foramen of Magendie to the telovelar junction. Looking through the aqueduct and at a point 5 mm superior to its inferior inlet, there was a small cherry-like blister protruding into the aqueductal anterior surface. This was used as an entry point to access the cavernoma. The space around the cavernoma was gently dissected and the cavernoma was circumferentially coagulated to shrink it in a concentric manner toward its center. RESULTS The total removal of the lesion was achieved and the histopathological findings were consistent with a cavernoma. As a result of noncommunicating hydrocephalus, the patient needed a ventriculoperitoneal shunt. The 1-year postoperative neurological examination was consistent with preoperative findings. CONCLUSION This report shows, for the first time, direct surgical removal of a cavernous hemangioma in the mesencephalic tegmentum via the aqueduct. This approach adds to contemporary microneurosurgery, respecting functional anatomy and minimizing neurological deficits.

Total Removal of Cavernous Hemangioma Using the Tonsillouveal Transaqueductal Approach (Method)

Recent advances in microsurgical techniques facilitate surgical resection of brainstem lesions that were previously considered inoperable. Cavernous hemangiomas with repeated hemorrhage that reach the pial surface or display progressive neurological deficits can be resected safely with acceptable morbidity. Various approaches to the mesencephalon or midbrain, tailored to the exact location of the lesion, have been described. In this chapter we describe a novel approach to the mesencephalic tegmentum via the aqueduct, adding to contemporary microneurosurgery, respecting functional anatomy and minimizing neurological deficits.