Initial experience with the Codman Certas adjustable valve in the management of patients with hydrocephalus
Fluids and Barriers of the CNS
Initial experience with the Codman Certas adjustable valve in the management of patients with hydrocephalus
Sara Watt 0
Niels Agerlin 0
Bertil Romner 0
0 The Neuroscience Centre, Department of Neurosurgery, Section NK 2092 , Blegdamsvej 9, Copenhagen DK-2100 , Denmark
Background: A new adjustable valve, the Codman CertasTM valve for treatment of hydrocephalus was introduced into clinical practice in January 2011. It has 8 different settings with an opening pressure varying from 36 to over 400 mm H2O at a flow rate of 20 mL/h. The 8th setting is designed to provide a "virtual off" function. The objective of this report is to describe the initial clinical experience with the CertasTM valve and evaluate clinical usage with the main focus on the portable adjustment device - Therapeutic Management System (TMS), the virtual off setting and compatibility with magnetic resonance imaging (MRI). Findings: Forty-two patients with hydrocephalus from different etiologies were treated with the CertasTM adjustable shunt system. Data regarding implantation procedures, the use of the TMS system, x-ray imaging, and MRI procedures were recorded prospectively. All patients had clinical follow-up at four weeks after implantation and every three months until a stable clinical condition was obtained. The mean time for follow-up was 8.6 months (1-16.6). Seventy-one adjustments were performed with the TMS, 12 were problematic. Twenty-nine MRI procedures were performed and did not cause accidental resetting. Five patients were treated with the "virtual off" function for a period. Conclusions: We found the CertasTM valve valuable in the treatment of hydrocephalus, usability of the TMS was high because it is small and portable, but in some cases we experienced adjustment problems with the first procedures performed by a surgeon, indicating that there is a learning curve. The "virtual off" function provided a possibility of treating over-drainage without the need for shunt ligation or other invasive procedures.
Hydrocephalus; Shunt; Certas valve; Adjustable valve; Programmable valve
Treating patients with hydrocephalus with an implanted
shunt is not always just straightforward and simple: there
are occurrences of under-drainage of cerebral spinal fluid
(CSF) where a large ventricle and clinical symptoms of
hydrocephalus continue or the shunt implantation may
cause over-drainage with slit ventricles and development
of subdural hygromas [1,2]. It has been shown that
adjustable valves can be useful in handling these problems
[3-6]. For nearly 25 years, different types of adjustable
valves have been on the market with a number of settings
from 3 to 20; these valves allow the neurosurgeon to
adjust the opening pressure non-invasively and thus
correct the volume of CSF shunted. A new adjustable valve,
The Codman Certas programmable valve, was approved
for clinical use in Europe and the USA in 2011. It can be
set to 7 different settings for drainage of CSF where the
opening pressure for each valve setting varies from 26
mmH2O (setting 1) to 247 mmH2O (setting 7) at a flow
rate of 20 mL/h. An 8th setting is designed to provide a
virtual off function of the valve, with a mean opening
pressure of 494 34 mmH2O when flow through the
valve should be at a minimum .
The valve system includes a portable adjustment
device, the Therapeutic Management System (TMS)
consisting of a locator, indicator and adjustment tool
(Figure 1). Non clinical testing has demonstrated that
the CertasTM valve can be considered MRI compatible
Figure 1 Therapeutic management system for the CertasTM valve. Locater tool (A), indicator tool (B), and adjustment tool (C).
and can be scanned safely under specific conditions,
provided that the static magnetic field is not larger than
3 T .
In this report we describe the initial clinical experience
with the CertasTM valve and evaluate its clinical value
with the main focus on the TMS, virtual off setting,
and MRI conditionality in the treatment of primary and
secondary hydrocephalus in a consecutive series of 42
Methods and results
Forty-two patients with hydrocephalus from different
etiologies were treated with the CertasTM adjustable
shunting system at the Rigshospitalet, Copenhagen
(Table 1). Patients were consecutively selected based on
etiology of hydrocephalus, in order to include patients
with communicating and non communicating
hydrocephalus from different etiologies. The patient
population consisted of 38% of all shunt implantations
Table 1 Etiology of hydrocephalus and the number of
patients who had adjustments of the valve setting
Etiology of hydrocephalus
Normal pressure hydrocephalus
Secondary to subarachnoid hemorrhage
Secondary to traumatic brain injury
Secondary to intraventricular hemorrhage
Secondary to meningitis
Giant aneurism obstruction
performed in the period and mean age was 56 years
(584), 4 children and 38 adults.
There were 22 first shunt implantations and 20 shunt
revisions with valve exchange, 26 of the implanted
systems included an anti-siphoning device and all
implantation procedures were performed by one of 12
specialists in neurosurgery and standardized according
to implantation of any ventriculoperitoneal shunt
(VPshunt). All patients had a clinical follow-up 4 weeks after
implantation and hereafter every 3 months until the
patient was in a stable condition. Data regarding
implantation procedures, the use of the TMS system, x-ray
imaging, and MRI procedures were recorded
prospectively at the time of surgery, during clinical follow-up and
at any admissions during the study period.
The mean time of follow-up was 8.6 months (116.6);
for patients with adjustments of valve settings it was
10.3 (2.6-16.6) while patients with non-adjusted valves
had a shorter follow-up of 5.9 (116.2) months. The
implantation of Codman CertasTM shunt system is a
standard procedure similar to implantation of other
shunt systems, no surgical revisions related to
malfunction of the valve were performed and no patients had
verified shunt infections or symptoms relating to this
A total of 71 adjustments were performed with the
TMS in 24 patients (Table 2), 12 adjustments were
problematic due to difficulties placing indicator or locator
tool correctly, resulting in a time consuming adjustment
process. The 18 patients who did not have adjustments,
had a sufficiently adequate clinical outcome after first
Twenty-nine cerebral MRIs were performed in 14
patients (6 at 3.0 T and 23 at 1.5 T), there was no
accidental readjustment of the valve setting as verified with
TMS and x-ray. The virtual off function, setting 8 was
used on five occasions due to over-drainage. Three
Table 2 Reasons for performing valve adjustments and
number of adjustments
Reason for adjustment
Optimising clinical status due to clinical symptoms of:
Normal pressure hydrocephalus
CT- results showing large ventricles
patients developed hygromas prior to implantation of a
CertasTM valve after hydrocephalus treatment with fixed
shunt types when the previous valve was exchanged for
a CertasTM valve with initial setting 8. Two additional
patients developed bilateral hygromas after implantation
of the CertasTM valve. In all 5 patients setting 8 was
maintained for a period until the hygromas had
diminished on CT examination. Subsequently the valve setting
was gradually decreased. No symptoms of hydrocephalus
were detected in any of the patients during treatment
with valve setting 8. X-ray verification of the valve
setting was performed after MRI and after problematic
adjustment procedures. The x-ray procedure for the
CertasTM valve was different from other similar valve
systems: the cassette is placed on the opposite side of
the valve while the camera must be placed on the valve
side perpendicular to the valve. The picture quality was
not always optimal.
We have presented our first experiences with the new
CertasTM valve including clinical advantages or
disadvantages with main focus on the TMS, MRI
conditionality and the virtual off setting.
The follow-up time for patients with adjustments of
the valve setting was longer (10.3 months) than
followup time for non-adjusted patients (5.9 months) because
all newly-adjusted patients had a clinical follow-up in
the out-patient clinic until the patient was in a stable
We experienced problems performing adjustments
with the TMS, mainly resulting in a time-consuming
adjustment process, but in three known cases the valve
setting was incorrect and led to over drainage and
development of hygromas in two patients and severe
symptoms in one patient. The problems primarily
occurred with the first adjustments procedures
performed by an individual surgeon, indicating that there
was a learning curve. To avoid adjustment problems in
the immediate post-operative period due to swelling, the
valve must be tunneled under the intact skin and rest on
bone and not in soft neck tissue. To avoid problems due
to incorrect placement of locator and indicator tool, it is
important to note that the locator tool must follow the
valve for the entire length of the valve, as an incorrect
position of just millimeters can lead to an incorrect valve
setting reading. Furthermore, new users should be
introduced to the TMS by an experienced user and trained in
the adjustment procedure.
Setting 8, the virtual off function is a key function in
the CertasTM valve, and in all of the patients where we
used setting 8, they avoided one or more invasive
procedures that would otherwise have been necessary. We
recommend that a specific procedure and instruction for
x-ray of CertasTM valve is written and followed.
Improvements could also be made in the design of the
valve in placement of radiopaque markers to make it
easier to verify valve settings on x-ray images. We
experienced no accidental change in the valve setting
after MRI procedures. MRI compatibility would be of
great value and this issue must be investigated further.
The valve produced MRI artifacts, but they can be
reduced by appropriate selection of pulse sequence
parameters  and only constitute a problem when the area
of interest is very close to the valve. This can be allowed
for by siting the valve appropriately at surgery.
At present there are five different adjustable valves on
the market (Table 3). The Codman Hakim programmable
valve (CHPV) has been described in many studies [3,5,6].
The adjustment system is not portable and accidental
readjustments have occurred with exposure to MRI
procedures and with exposure to magnetic toys [10,11]. The
Strata valve is very similar to the CertasTM valve in design
and includes a portable adjustment system quite similar
to the TMS. It has also been reported to accidently
Table 3 Relevant individual features of adjustable valves
Number of settings
*Available in 4 different setting intervals with 5 possible settings.
change settings with exposure to both MRI and magnetic
toys . The Sophysa Polaris valve includes a portable
adjustment system with a compass tool to indicate
correct positioning of indicator tool over the valve . The
MIETHKE proGAVW valve includes a gravitational
device [13,14]. The Sophysa Polaris and the MIETHKE
proGAV valve are both MRI compatible up to 3.0 T but they
have no virtual off function.
We found the CertasTM valve valuable in the treatment
of hydrocephalus, usability of the TMS was high because
it is small and portable, but in some cases we
experienced adjustment problems when surgeons were
inexperienced. New users should be introduced to the TMS
by an experienced user and trained in the adjustment
procedure. The virtual off function provided the
possibility of treating over-drainage without the need for
shunt ligation or other invasive procedures. Twenty-nine
MRI procedures caused no accidental resetting of the
valve, but MRI compatibility needs further investigation.
There are no competing interests or conflicts of interest for any of the
authors, the Codman Company has not had any influence in our work and
we have not received any payment of any kind. Bertil Romner is a consultant
for the company, but this has not influenced our present report, neither
have we received any funding or financial support and the work has been
interpreted solely by us and has not been published elsewhere in any form.
SW contributed to design and planning of the study, acquisition of data,
analyzed, interpreted data and drafted the manuscript. NA contributed
substantially in the acquisition of data, and was involved in drafting the
manuscript. BR contributed to the conception and design of the study, and
has critically revised the draft for content and form. All authors have read
and approved the final version of the manuscript.
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