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Background: No standard has been established regarding timing and choice of strategy for discontinuation of external ventricular drainage (EVD) in patients with aneurysmal subarachnoid haemorrhage (aSAH), and little is known about the importance of clinical variables. A proportion of the patients who initially pass their discontinuation attempt return with delayed hydrocephalus and the need of a permanent shunt. Early differentiation between patients who need a shunt and those who do not would facilitate care. We conducted a retrospective analysis on patients with aSAH and an EVD to search significant differences in treatment and clinical variables between patients who received a permanent shunt during initial hospitalization or after readmission, and those who never received a shunt., Methods: We included 183 patients with aSAH who received an EVD over a 4-year period between 2015 and 2018 and divided them into three groups: those who received a shunt during primary admission, those who were readmitted for delayed hydrocephalus and received a shunt, and those who never needed a shunt. Between these groups, we compared selected clinical variables as well as outcome at discharge and after 6 months. Additionally, we assessed the ability of a shunt dependency score (SDASH) to predict the need for permanent drainage in the patients., Results: Of 183 included patients, 108 (59%) ultimately received a ventriculoperitoneal (VP) shunt. Of these, 89 (82%) failed discontinuation during the primary admission and received a permanent shunt before discharge from the neurosurgical department. The remaining 19 (18%) were discharged after successful discontinuation, but subsequently developed delayed hydrocephalus and were admitted for shunt placement a median of 39 (range: 18-235) days after ictus. Ninety-four patients were discharged after successful discontinuation of the EVD, consisting of those who never developed the need for a permanent shunt and the 19 who were readmitted with delayed hydrocephalus, corresponding to a 20% (19/94) readmittance rate. Clinical variables such as drainage volume or discontinuation strategy did not differ across the three groups of patients. The SDASH score failed to provide any clinically useful information regarding prediction of shunt placement., Conclusion: In this study, clinical variables including use of the predictive score SDASH predicted neither the overall need for nor the timing of shunt placement after aSAH. The homogeneous distribution of data between the three different groups renders strong independent clinical predictive factors unlikely. Thus, attempts to predict a permanent shunt requirement from these variables may be futile in these patients., (© 2024. The Author(s).)

Objective: Decompressive hinge craniotomy (DHC) is an alternative treatment option to decompressive craniectomy (DC) for elevated intracranial pressure (ICP). The aim of this study was to characterize the difference in pressure-volume relationship between DHC and DC., Methods: We compared the intracranial pressure-volume relationship in a human cadaver model following either DHC, DC, or fixing of the bone plate by titanium clamps. We inserted an intracranial expandable device in two human cadaver specimens, performed either DHC, DC, or bone plate fixation, and gradually increased the intracranial volume while measuring ICP. Following DHC, we also performed CT-scans at pre-defined intervals., Results: Before ICP exceeded a threshold of 20 mmHg, a fixed bone plate tolerated an increase of 130 ml of intracranial volume, while DHC and DC allowed an increase of 190 ml and 290 ml, respectively. CT-derived calculations following DHC determined that the increase in intracranial volume at ICP 22 mmHg was 65 ml, the maximal increase of intracranial volume was 84 ml, the maximal bone displacement was 21 mm, and the bone plate volume to be 82 ml. Manual stress test of the hinged bone plate did not allow misalignment or intracranial displacement of the bone plate., Conclusion: DHC increases the intracranial volume by up to 84 ml and allows for approximately 60 ml increase of intracranial volume before ICP exceeds 20 mmHg. This indicates, when comparing with results from previous studies of herniation volumes, that DHC will be sufficient in many patients with head injury or cerebral infarction with treatment refractory intracranial hypertension., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: The standard lumbar puncture position involves maximum flexion of both lumbar and cervical spine. The cerebrospinal fluid opening pressure (CSF op ) is measured in a horizontal position. This study investigated if flexion of hip and neck both separately and simultaneously influence intracranial pressure (ICP) to a clinically relevant extent., Methods: Thirty-nine patients, undergoing invasive ICP monitoring as part of diagnostic work-up, were included. The patients underwent either a vertical postural examination (n = 24) or a horizontal postural examination (n = 15) to examine a varying degree of spine flexion., Results: The vertical examination showed that ICP decreased by 15.2 mmHg when straightening the neck in a sitting lumbar puncture position (n = 24, IQR - 20.1 to - 9.7). In the horizontal examination, ICP increased in all but one patient when changing from supine position to lateral recumbent position (n = 15, median increase of 6.9 mmHg, IQR 3.1 to 9.9). Straightening the hips alone decreased ICP with 0.2 mmHg (n = 15, IQR - 0.5 to 2.0), while straightening the neck alone decreased ICP by 4.0 mmHg (n = 15, IQR - 5.9 to - 1.7). However, when straightening the hip and neck simultaneously ICP decreased by 6.4 mmHg (n = 6, IQR - 9.5 to - 4.4)., Conclusions: Neck flexion alone, and neck flexion and hip flexion in combination, has significant confounding influence on ICP. This may cause patients to shift from a normal ICP range to a pathological ICP range, which will potentially affect treatment decisions. Consensus on guidelines for body position including neck and hip flexion measuring CSF op may be needed.

Background: Hydrocephalus requiring external ventricular drainage is common following aneurysmal subarachnoid hemorrhage (aSAH). Timing and strategy for the discontinuation of the external ventricular drain (EVD) are, however, controversial as guidelines are based on limited scientific evidence. A recent similar survey showed that guidelines and recommendations are not being followed. We conducted a questionnaire survey regarding the management of EVD treatment in patients with aSAH and investigated current treatment practice, consensus, and adherence to guidelines within the neurosurgical departments in Scandinavia., Methods: A questionnaire concerning the management of EVD discontinuation in patients with hydrocephalus following aSAH was distributed to all 14 neurosurgical departments in Scandinavia (Norway, Sweden, and Denmark). Neurosurgeons and neurosurgical trainees at all levels were asked to complete the questionnaire individually. A total of 175 completed questionnaires were received between May 2018 and April 2019, resulting in a response rate of 64 %., Results: Eighty-five percent of respondents reported no knowledge of international guidelines regarding EVD discontinuation in patients with hydrocephalus following aSAH. Within every department, respondents disagreed on whether a common discontinuation strategy was followed or not. Seventy-four percent decided upon the EVD discontinuation strategy mainly determined by patients' clinical condition and drainage volume. Forty-five percent considered Glasgow Coma Score (GCS) the most important clinical variable when assessing the timing of EVD discontinuation. There was general agreement towards the initiation of EVD discontinuation 4-7 days after ictus of aSAH in a stable patient with a drainage volume of < 150 ml/day and intracranial pressure (ICP) < 15 mmHg., Conclusion: Awareness of and adherence to international guidelines regarding EVD discontinuation in patients with hydrocephalus following aSAH were limited in Scandinavia. Internal consensus at department level was absent. Initiation of the discontinuation process appeared to be case dependent and mainly influenced by the patients' clinical condition and drainage volume. GCS was the clinical variable considered most important when deciding on the initiation of EVD discontinuation.

Background: Infusion tests, which measure resistance to outflow (R out ), are used in selecting patients suspected for idiopathic normal pressure hydrocephalus (iNPH) for shunt surgery. Infusion tests can be performed through an external ventricular drain (EVD). A 24-hour time gap from EVD insertion to an infusion test is a routine practice at our department due to concerns that the surgical procedure might influence the test results in the immediate postoperative period. The objective of the study was to investigate if timing of an intraventricular infusion test influences the results of the test in patients suspected for iNPH., Methods: Ten patients scheduled for an intraventricular infusion test were included. Measurements of baseline intracranial pressure (ICP) and plateau ICP were obtained during constant rate intraventricular infusion test performed at two time points (1 and 24 h after EVD insertion) and R out was calculated from these measures and compared within patients., Results: Eight patients completed both infusion tests. In one of the 18 infusion tests performed, it was not possible to define an ICP plateau and this infusion test was excluded, leaving 7 paired infusion tests. Median R out was 12.9 mmHg/ml/min (range 7.0-22.0) 1 h after EVD insertion and 11.3 mmHg/ml/min (range 7.8-18.1) after 24 h. Overall, there were no statistically significant differences in R out (P = 0.83), baseline ICP (P = 0.70), or plateau ICP (P = 0.81) between the recordings performed 1 h and 24 h after EVD insertion. For two of the seven patients with paired infusion tests, there was poor agreement between R out values at 1 and 24 h., Conclusion: Overall, R out estimates do not change significantly between 1 and 24 h after EVD insertion. We therefore propose that infusion tests can be performed shortly after surgery to reduce the period of indwelling EVD and duration of hospitalization.

Background: Telemetric intracranial pressure (ICP) monitoring enable long-term ICP monitoring on patients during normal day activities and may accordingly be of use during evaluation and treatment of complicated ICP disorders. However, the benefits of such equipment depend strongly on the validity of the recordings and how often the telemetric sensor needs to be re-implanted. This study investigates the clinical and technical sensor survival time and drift of the telemetric ICP sensor: Raumedic Neurovent-P-tel., Methods: Implanted telemetric ICP sensors in the period from January 2011 to December 2017 were identified, and medical records reviewed for complications, explantation reasons, and parameters relevant for determining clinical and technical sensor survival time. Explanted sensors were tested in an experimental setup to study baseline drift., Results: In total, implantation of 119 sensors were identified. Five sensors (4.2%) were explanted due to skin damage, three (2.5%) due to wound infection, and two (1.7%) due to ethylene oxide allergy. No other complications were observed. The median clinical sensor survival time was 208 days (95% CI 150-382). The median technical sensor survival time was 556 days (95% CI 382-605). Explanted sensors had a median baseline drift of 2.5 mmHg (IQR 2.0-5.5)., Conclusion: In most cases, the ICP sensor provides reliable measurements beyond the approved implantation time of 90 days. Thus, the sensor should not be routinely removed after this period, if ICP monitoring is still indicated. However, some sensors showed technical malfunction prior to the CE-approval, underlining that caution should always be taken when analyzing telemetric ICP curves.