Reconsidering Ventriculoperitoneal Shunt Surgery and Postoperative Shunt Valve Pressure Adjustment: Our Approaches Learned From Past Challenges and Failures

Treatment for idiopathic normal pressure hydrocephalus (iNPH) continues to develop. Although ventriculoperitoneal shunt surgery has a long history and is one of the most established neurosurgeries, in the 1970s, the improvement rate of iNPH triad symptoms was poor and the risks related to shunt implantation were high. This led experts to question the surgical indication for iNPH and, over the next 20 years, cerebrospinal fluid (CSF) shunt surgery for iNPH fell out of favor and was rarely performed. However, the development of programmable-pressure shunt valve devices has reduced the major complications associated with the CSF drainage volume and appears to have increased shunt effectiveness. In addition, the development of support devices for the placement of ventricular catheters including preoperative virtual simulation and navigation systems has increased the certainty of ventriculoperitoneal shunt surgery. Secure shunt implantation is the most important prognostic indicator, but ensuring optimal initial valve pressure is also important. Since over-drainage is most likely to occur in the month after shunting, it is generally believed that a high initial setting of shunt valve pressure is the safest option. However, this does not always result in sufficient improvement of the symptoms in the early period after shunting. In fact, evidence suggests that setting the optimal valve pressure early after shunting may cause symptoms to improve earlier. This leads to improved quality of life and better long-term independent living expectations. However, in iNPH patients, the remaining symptoms may worsen again after several years, even when there is initial improvement due to setting the optimal valve pressure early after shunting. Because of the possibility of insufficient CSF drainage, the valve pressure should be reduced by one step (2–4 cmH2O) after 6 months to a year after shunting to maximize symptom improvement. After the valve pressure is reduced, a head CT scan is advised a month later.

P.227 Investigating the changes in ITP after CSF drainage in patients with acute traumatic SCI: Results from a Quaternary Spinal Care Center

Background: Mean arterial pressure augmentation is one current established practice for management of patients with SCI. We present the first data investigating the effectiveness of Intrathecal Pressure (ITP) reduction through CSF drainage (CSFD) in managing patients with acute traumatic SCI at a large academic center. Methods: Data from 6 patients with acute traumatic SCI were included. A lumbar intrathecal catheter was used to monitor ITP and volume of CSFD. CSFD was performed and recorded hourly. ITP recordings were collected hourly and the change in ITP was calculated (hour after minus before CSFD). 369 data points were collected and change in ITP was plotted against volume of CSFD. Results: Data across all patients showed variability in the ITP over time without a significant trend (slope=0.016). We found no significant change in ITP with varying amounts of CSFD (slope=0.007, r2=0.00, p=0.88). Changes in ITP were not significantly different across groups of CSFD but the variation in the data decreased with increasing levels of CSFD. Conclusions: We present the first known data on changes in ITP with varying degrees of CSFD in patients with acute traumatic SCI. These results may provide insight into the complexity of ITP changes in patients post-injury and help inform future SCI management.

Intracranial pressure dynamics and cerebral vasomotor reactivity in community-acquired bacterial meningitis during neurointensive care

OBJECTIVE Community-acquired bacterial meningitis (CABM) is a severe condition associated with high mortality. In this study the first aim was to evaluate the incidence of intracranial pressure (ICP) insults and disturbances in cerebral vasomotor reactivity and the second aim was to evaluate the management and clinical outcome of CABM patients treated in the neurointensive care unit (NICU). METHODS CABM patients who were treated in the NICU of Uppsala University Hospital, Sweden, during 2008–2020 were included in the study. Data on demographics, admission variables, treatment, ICP dynamics, vasomotor reactivity, and short-term clinical outcome were evaluated in these patients. RESULTS Of 97 CABM patients, 81 (84%) received ICP monitoring, of whom 22% had ICP > 20 mm Hg during 5% or more of the monitoring time on day 1, which decreased to 9% on day 3. For those patients with ICP monitoring, 46% required CSF drainage, but last-tier ICP treatment, including thiopental (4%) and decompressive craniectomy (1%), was rare. Cerebral vasomotor reactivity was disturbed, with a mean pressure reactivity index (PRx) above 0.2 in 45% of the patients on day 1, and remained high for the first 3 days. In total, 81 (84%) patients had a favorable outcome (Glasgow Coma Scale motor score [GCS M] 6) at discharge, 9 (9%) patients had an unfavorable outcome (GCS M < 6) at discharge, and 7 (7%) patients died in the NICU. Those with favorable outcome had significantly better cerebral vasomotor reactivity (lower PRx) than the two other outcome groups (p < 0.01). CONCLUSIONS Intracranial hypertension was frequent following severe CABM and CSF drainage was often sufficient to control ICP. Cerebral vasomotor reactivity was commonly disturbed and associated with poor outcome. Clinical outcome was slightly better than in earlier studies.

Implementation of an Automated Cerebrospinal Fluid Drainage System for Early Mobilization in Neurosurgical Patients

Background: Automated cerebrospinal fluid (CSF) drainage systems allow for the mobilization of patients with an external CSF drain. The aim of this study is to describe the implementation of an automated CSF drainage system in neurosurgical patients with external CSF drains. Methods: A feasibility study was performed using an automated CSF drainage system (LiquoGuard®7, Möller Medical GmbH, Fulda, Germany) in adult neurosurgical patients treated with external lumbar or external ventricular drains between December 2017 and June 2020. Limited mobilization was allowed—patients were allowed to adjust their inclined beds, sit in chairs and walk under the supervision of a nurse or physical therapist. The primary outcome was the number of prematurely terminated drainage sessions. Results: Twenty-three patients were included. Drainage was terminated prematurely in eight (35%) patients. In three (13%) of these patients, drainage was terminated due to signs of hydrocephalus. Pressure-controlled drainage in patients with external lumbar drains (ELD) showed inaccurate pressure curves, which was solved by using volume-controlled drainage in ELD patients. Conclusion: The implementation of an automated CSF drainage system (LiquoGuard®7) for CSF drainage allows for early mobilization in a subset of patients with external CSF drains. External lumbar drains require volume-based drainage rather than differential pressure-dependent drainage.

Point-of-care detection of lactate in cerebrospinal fluid

Purpose Measurements of cerebrospinal fluid (CSF) lactate can aid in detecting infections of the central nervous system and surrounding structures. Neurosurgical patients with temporary lumbar or ventricular CSF drainage harbor an increased risk for developing infections of the central nervous system, which require immediate therapeutic responses. Since blood gas analyzers enable rapid blood-lactate measurements, we were interested in finding out if we can reliably measure CSF-lactate by this point-of-care technique. Methods Neurosurgical patients on our intensive care unit (ICU) with either lumbar or external ventricular drainage due to a variety of reasons were included in this prospective observational study. Standard of care included measurements of leucocyte counts, total protein and lactate measurements in CSF by the neurochemical laboratory of our University Medical Center twice a week. With respect to this study, we additionally performed nearly daily measurements of cerebrospinal fluid by blood gas analyzers to determine the reliability of CSF-lactate measured by blood gas analyzers as compared to the standard measurements with a certified device. Results 62 patients were included in this study. We performed 514 CSF-lactate measurements with blood gas analyzers and compared 180 of these to the in-house standard CSF-lactate measurements. Both techniques correlated highly significantly (Pearson correlation index 0.94) even though lacking full concordance in a Bland–Altman plotting. Of particular importance, regular measurements enabled immediate detection of central infection in three patients who had developed meningitis during the course of their treatment. Conclusion Blood gas analyzers measure CSF-lactate with sufficient reliability and can help in the timely detection of a developing meningitis. In addition to and triggering established CSF diagnostics, CSF-lactate measurements by blood gas analyzers may improve surveillance of patients with CSF drainage. This study was retrospectively registered on April 20th 2020 in the German trial register. The trial registration number is DRKS00021466.

Evaluating the Role of Pre-operative Cerebrospinal Fluid Diversion by Lumbar Drain in Transnasal Transsphenoidal Tumor Surgeries

Background and Aim: The major concerns related to the Endoscopic Endonasal Transsphenoidal (EET) surgery for sellar and suprasellar tumors include the risks of post-operative Cerebrospinal Fluid (CSF) leak, leading to morbidity and at times mortality, due to severe meningitis. Time is required to develop possible preventive measures that can reduce the risk of post-operative CSF rhinorrhea. The present study aimed to evaluate the effects of pre-operative CSF diversion by lumbar drainage in EET tumor surgeries on preventing post-operative CSF leak and its effect on the length of hospital stay. Methods and Materials/Patients: We conducted a prospective study on 20 patients with a pituitary tumor that underwent EET surgery between October 2018 and December 2019. Preoperative Lumbar Drain (LD) was inserted after induction in all explored patients. The tumor was excised with continuous intraoperative CSF drainage. Post-operatively, the LD was kept for 3 days and clamped for the next 24 hours. If no evidence of CSF rhinorrhea was present, it was removed. Complications related to CSF drainage, CSF leak, and hospital stays were evaluated. Results: Our study population consisted of 13(65%) men and 7(35%) women, with Mean±SD age of 39.8±10.71 years. The most commonly presented complaint was visual disturbance (60%) and the least common symptom was urinary disturbance (5%). The intra-operative leak was detected in 9(45%) patients, while the post-operative leak was present in only 1(5%) patient. LD blockage significantly contributed to post-operative CSF leak (P=0.001). The Mean±SD hospital stay in the post-operative period was 8.85±3.22 days with 65% of patients having a hospital stay of <7 days. Other post-operative complications (e.g. diabetes insipidus, electrolyte imbalance, and hormonal disturbances) were mainly responsible for prolonged post-operative hospital stay (P=0.001). Conclusion: Pre-operative LD, apart from helping to reduce the incidence of post-operative CSF leak, is not associated with an overall increased post-operative hospital stay.

Point-of-care Detection of Lactate in Cerebrospinal Fluid

Purpose: Measurements of cerebrospinal fluid (CSF)-lactate can aid in detecting infections of the central nervous system and surrounding structures. Neurosurgical patients with temporary lumbar or ventricular CSF-drainage harbor an increased risk for developing infections of the central nervous system which require immediate therapeutic responses. Since blood-gas-analyzers enable rapid blood-lactate-measurements we were interested to find out if CSF-lactate may be reliably measured by this point-of-care technique. Methods: Neurosurgical patients on our intensive care unit (ICU) with either lumbar or external ventricular drainage due to a variety of reasons were included in this prospective observational study. Standard of care included measurements of leucocyte counts, total protein and lactate measurements in CSF by the neurochemical laboratory of our University Medical Center twice a week. With respect to this study we additionally performed nearly daily measurements of cerebrospinal-fluid by blood gas analyzers to determine the reliability of CSF-lactate measured by blood-gas-analyzers as compared to the standard measurements with a certified device. Results: 62 patients were included in this study. 514 CSF measurements were performed with blood-gas-analyzers. 180 of these could be compared to the in-house standard CSF-lactate measurements. Both techniques correlated highly significant (Pearson correlation index 0.94) even though lacking full concordance in a Bland-Altman-plotting. Of particular importance, regular measurements enabled immediate detection of central infection in 3 patients who had developed meningitis during the course of their treatment.Conclusion: CSF-lactate was reliably measured by blood-gas-analyzers and detected developing meningitis timely. In addition to and triggering established CSF-diagnostics, CSF-lactate measurements by blood-gas-analyzers may improve surveillance of central nervous infections in patients with CSF-drainage. This study was retrospectively registered on April 20th 2020 in the German trial register. The trial registration number is: DRKS00021466.

Systematic volumetric analysis predicts response to CSF drainage and outcome to shunt surgery in idiopathic normal pressure hydrocephalus

Objectives Idiopathic normal pressure hydrocephalus (INPH) is a neurodegenerative disorder characterized by excess cerebrospinal fluid (CSF) in the ventricles, which can be diagnosed by invasive CSF drainage test and treated by shunt placement. Here, we aim to investigate the diagnostic and prognostic power of systematic volumetric analysis based on brain structural MRI for INPH. Methods We performed a retrospective study with a cohort of 104 probable INPH patients who underwent CSF drainage tests and another cohort of 41 INPH patients who had shunt placement. High-resolution T1-weighted images of the patients were segmented using an automated pipeline into 283 structures that are grouped into different granularity levels for volumetric analysis. Volumes at multi-granularity levels were used in a recursive feature elimination model to classify CSF drainage responders and non-responders. We then used pre-surgical brain volumes to predict Tinetti and MMSE scores after shunting, based on the least absolute shrinkage and selection operator. Results The classification accuracy of differentiating the CSF drainage responders and non-responders increased as the granularity increased. The highest diagnostic accuracy was achieved at the finest segmentation with a sensitivity/specificity/precision/accuracy of 0.89/0.91/0.84/0.90 and an area under the curve of 0.94. The predicted post-surgical neurological scores showed high correlations with the ground truth, with r = 0.80 for Tinetti and r = 0.88 for MMSE. The anatomical features that played important roles in the diagnostic and prognostic tasks were also illustrated. Conclusions We demonstrated that volumetric analysis with fine segmentation could reliably differentiate CSF drainage responders from other INPH-like patients, and it could accurately predict the neurological outcomes after shunting. Key Points • We performed a fully automated segmentation of brain MRI at multiple granularity levels for systematic volumetric analysis of idiopathic normal pressure hydrocephalus (INPH) patients. • We were able to differentiate patients that responded to CSF drainage test with an accuracy of 0.90 and area under the curve of 0.94 in a cohort of 104 probable INPH patients, as well as to predict the post-shunt gait and cognitive scores with a coefficient of 0.80 for Tinetti and 0.88 for MMSE. • Feature analysis showed the inferior lateral ventricle, bilateral hippocampus, and orbital cortex are positive indicators of CSF drainage responders, whereas the posterior deep white matter and parietal subcortical white matter were negative predictors.