The benefits of automated CSF drainage in normal pressure hydrocephalus.

BACKGROUND: The commonly used cerebrospinal fluid (CSF) drainage system remains the manual drip-chamber drain. The LiquoGuard (Möller Medical GmbH, Germany) is an automated CSF management device with dual functionality, measuring intracranial pressure and automatic pressure- or volume-led CSF drainage. There is limited research for comparison of devices, particularly in the neurosurgical field, where it has potential to reshape care. OBJECTIVE: This study aims to compare manual drip-chamber drain versus LiquoGuard system, by assessing accuracy of drainage, associated morbidity and impact on length of stay. METHOD: Inclusion criteria consisted of suspected normal pressure hydrocephalus (NPH) patients undergoing extended lumbar drainage. Patients were divided into manual drain group versus automated group. RESULTS: Data was analysed from 42 patients: 31 in the manual group versus 11 in the LiquoGuard group. Volumetric over-drainage was seen in 90.3% (n = 28) versus 0% (p < 0.05), and under-drainage in 38.7% (n = 12) versus 0% (p < 0.05), in the manual and automatic group, respectively. Symptoms of over-drainage were noted in 54.8% (n = 17) of the manual group, all of which had episodes of volumetric over-drainage, versus 18.2% (n = 2) in automated group, of which neither had actual over-drainage (p < 0.05). Higher over-drainage symptoms of manual drain is likely due to increased fluctuation of CSF drainage, instead of smooth CSF drainage seen with LiquoGuard system. An increased length of stay was seen in 38.7% (n = 12) versus 9% (n = 1) (p < 0.05) in the manual and LiquoGuard group, respectively. CONCLUSION: The LiquoGuard device is a more superior way of CSF drainage in suspected NPH patients, with reduced morbidity and length of stay.

The initial intracranial pressure spike phenomenon.

BACKGROUND: Elective use of intraparenchymal intracranial pressure (ICP) monitoring is a valuable resource in the investigation of hydrocephalus and other cerebrospinal fluid disorders. Our preliminary study aims to investigate ICP changes in the immediate period following dural breach, which has not yet been reported on. METHOD: This is a prospective cohort study of patients undergoing elective ICP monitoring, recruited between March and May 2022. ICP readings were obtained at opening and then at 5-min intervals for a 30-min duration. RESULTS: Ten patients were recruited, mean age 45 years, with indications of a Chiari malformation (n = 5), idiopathic intracranial hypertension (n = 3) or other ICP-related pathology (n = 2). Patients received intermittent bolus sedation (80%) vs general anaesthesia (20%). Mean opening pressure was 22.9 mmHg [± 6.0], with statistically significant decreases present every 5 min, to a total reduction of 15.2 mmHg at 20 min (p = < 0.0001), whereafter the ICP plateaued with no further statistical change. DISCUSSION: Our results highlight an intracranial opening pressure 'spike' phenomenon. This spike was 15.2 mmHg higher than the plateau, which is reached at 20 min after insertion. Several possible causes exist which require further research in larger cohorts, including sedation and pain response. Regardless of causation, this study provides key information on the use of ICP monitoring devices, guiding interpretation and when to obtain measurements.

Cerebrospinal fluid production rate in various pathological conditions: a preliminary study.

INTRODUCTION: The cerebrospinal fluid (CSF) production rate in humans is not clearly defined but is estimated to be 18-24 ml/h (Trevisi et al Croat Med J 55(4):377-387 (24); Casey and Vries Childs Nerv Syst 5(5):332-334 (8)). A frequent clinical observation is that patients often drain higher volumes of CSF than can be explained by the assumed 'normal' CSF production rate (PRcsf). In the National Hospital for Neurology and Neurosurgery PRcsf was recorded in a variety of common neurosurgical pathologies using LiquoGuard7, an automated peristaltic pump that accurately controls CSF drainage and maintains a pre-set CSF pressure. METHODS: A prospective observational study was performed from September 2021 onwards, on all patients in the National Hospital for Neurology and Neurosurgery who required CSF drainage as part of their ongoing treatment. The external drain was connected to a LiquoGuard7 pump (Möller Medical GmbH, Fulda, Germany), and the internal software of LiquoGuard7 was used to measure PRcsf. Statistical analysis used SPSS (version 25.0, IBM) by paired t test, comparing measured rates to hypothetical 'normal' CSF production rates calculated and published by Ekstedt (16-34ml/h) (Ekstedt J Neurol Neurosurg Psychiatry 41(4):345-353 (14)), assuming a similar distribution. RESULTS: PRcsf was calculated in 164 patients. Suspected normal pressure hydrocephalus (n=41): PRcsf of 79ml/h±20SD (p<0.0001). Post-surgical CSF leak (n=26): PRcsf of 90ml/h±20SD (p<0.0001). Subarachnoid haemorrhage (n=34): PRcsf of 143ml/h±9SD (p<0.0001). Intracerebral haemorrhage (n=22): PRcsf of 137ml/h±20SD (p<0.0001). Spinal lesions (n=7): PRcsf of 130ml/h±20SD (p<0.0032). Pituitary adenomas (n=10): PRcsf of 29 ml/h±9SD (p<0.049). Idiopathic intracranial hypertension (n=15): PRcsf of 86ml/h±10SD (p<0.0001). Decompensated long-standing overt ventriculomegaly (n=4): PRcsf of 65ml/h±10SD (p<0.0001). Cerebral infection (n=5): PRcsf of 90ml/h±20SD (p<0.0001). CONCLUSION: Net CSF production rate may be higher than expected in many conditions, as measured with new device LiquoGuard7 through the study of net flow rate, which may have implications for clinical decisions on CSF diversion. The conventional understanding of CSF production and circulation does not explain the findings of this study. More extensive studies are needed to validate this technique.

ICP during head movement: significance of the venous system.

BACKGROUND: It is thought that the internal jugular veins (IJV) are the primary route for cranial venous outflow in supine position and the vertebral venous plexus when upright. Previous studies have noted a greater increase in intracranial pressure (ICP) when subjects turn their head in one direction compared to the other, but no clear cause had been investigated. We hypothesised that in the supine position, head turning and consequently obstructing the IJV draining the dominant transverse sinus (TVS) would lead to a greater rise in ICP compared to turning to the non-dominant side. METHODS: A prospective study in a large-volume neurosurgical centre. Patients undergoing continuous ICP monitoring as part of their standard clinical management were recruited. Immediate ICP was measured in different head positions (neutral, rotated to the right and left) when supine, seated, and standing. TVS dominance was established by consultant radiologist report on venous imaging. RESULTS: Twenty patients were included in the study, with a median age of 44 years. Venous system measurements revealed 85% right-sided vs 15% left-sided dominance. Immediate ICP rose more when head turning from neutral to the dominant TVS (21.93mmHg ± 4.39) vs non-dominant side (16.66mmHg ± 2.71) (p= <0.0001). There was no significant relationship in the sitting (6.08mmHg ± 3.86 vs 4.79mmHg ± 3.81, p = 0.13) or standing positions (8.74mmHg ± 4.30 vs 6.76mmHg ± 4.14, p =0.07). CONCLUSION: This study has provided further evidence that the transverse venous sinus to internal jugular system pathway is the likely primary venous drainage when supine; and quantified its effect when head turning on ICP. It may guide patient-specific nursing care and advice.

Long-term oncological outcomes after haemorrhagic apoplexy in pituitary adenoma managed operatively and non-operatively.

INTRODUCTION: Depending on severity of presentation, pituitary apoplexy can be managed with acute surgery or non-operatively. We aim to assess long-term tumour control, visual and endocrinological outcomes following pituitary apoplexy with special emphasis on patients treated non-operatively. METHODS: Multicentre retrospective cohort study. All patients with symptomatic pituitary apoplexy were included. Patients were divided into 3 groups: group 1: surgery within 7 days; group 2: surgery 7 days-3 months; group 3: non-operative. Further intervention for oncological reasons during follow-up was the primary outcome. Secondary outcome measures included visual and endocrinological function at last follow-up. RESULTS: One hundred sixty patients were identified with mean follow-up of 48 months (n = 61 group 1; n = 34 group 2; n = 64 group 3). Factors influencing decision for surgical treatment included visual acuity loss (OR: 2.50; 95% CI: 1.02-6.10), oculomotor nerve palsy (OR: 2.80; 95% CI: 1.08-7.25) and compression of chiasm on imaging (OR: 9.50; 95% CI: 2.06-43.73). Treatment for tumour progression/recurrence was required in 17%, 37% and 24% in groups 1, 2 and 3, respectively (p = 0.07). Urgent surgery (OR: 0.16; 95% CI: 0.04-0.59) and tumour regression on follow-up (OR: 0.04; 95% CI: 0.04-0.36) were independently associated with long-term tumour control. Visual and endocrinological outcomes were comparable between groups. CONCLUSION: Urgent surgery is an independent predictor of long-term tumour control following pituitary apoplexy. However, 76% of patients who successfully complete 3 months of non-operative treatment may not require any intervention in the long term.

Can clinicians correctly predict intracranial pressure state based on clinical symptoms alone in shunted patients?

BACKGROUND: Clinicians are well-versed in the classical symptoms of low vs. high intracranial pressure (ICP). However, symptoms may not be as predictable of ICP state in shunted patients with chronic symptoms. In this study, we assess whether clinicians can predict high vs. low ICP state in chronically symptomatic shunted patients without any diagnostic clues. METHODS: A detailed retrospective analysis was performed on 259 patients undergoing ICP monitoring. A total of 17 patients who had a ventriculoperitoneal shunt were identified, with a suspected chronic abnormal ICP state based only on clinical symptoms. Patients with investigations guiding towards a likely pressure state were excluded, e.g., imaging or ophthalmological findings suggestive of ICP state. RESULTS: Clinical suspicion of ICP state was incorrect in 16 out of 17 cases (P<0.05). The symptoms described by patients were suggestive of abnormal ICP states; however, 13 out of 17 cases demonstrated ICP within the normal range (-1.3 to 5.3 mmHg). Three patients with occipital headaches worse on standing, typical of low-pressure symptoms, were in fact shown to have ICP above 10.0 mmHg. CONCLUSIONS: This study casts doubt on the utility of classic symptoms in diagnosing abnormal ICP state in chronically symptomatic shunted patients with equivocal adjuncts. Additionally, it highlights the importance of ICP monitoring for this patient group.

The Need for Head Protection Protocols for Craniectomy Patients during Rest, Transfers and Turning.

After craniectomy, patients are generally advised to wear a helmet when mobilising to protect the unshielded brain from damage. However, there exists limited guidance regarding head protection for patients at rest and when being transferred or turned. Here, we emphasise the need for such protocols and utilise evidence from several sources to affirm our viewpoint. A literature search was first performed using MEDLINE and EMBASE, looking for published material relating to head protection for patients post-craniectomy during rest, transfer or turning. No articles were identified using a wide-ranging search strategy. Next, we surveyed and interviewed staff and patients from our neurosurgical centre to ascertain how often their craniectomy site was exposed to external pressure and the precautions taken to prevent this. 59% of patients admitted resting in contact with the craniectomy site, in agreement with the observations of 67% of staff. In 63% of these patients, this occurred on a daily basis and for some, was associated with symptoms suggestive of raised intracranial pressure. 44% of staff did not use a method to prevent craniectomy site contact while 65% utilised no additional precautions during transfer or turning. 63% of patients received no information about avoiding craniectomy site contact upon discharge, and almost all surveyed wished for resting head protection if it were available. We argue that pragmatic guidelines are needed and that our results support this perspective. As such, we offer a simple, practical protocol which can be adopted and iteratively improved as further evidence becomes available in this area.

Novel telemetric pressure monitoring in lumbar theca.

Introduction: There is no previous literature on the use of telemetric sensors (telesensor) in the lumbar theca. We aim to provide novel data on telemetric pressure monitoring of the lumbar theca via lumboperitoneal shunts. Research question: Primary outcome is telemetric sensor malfunction of lumboperitoneal shunt. The secondary outcome is post-operative complications. Materials and methods: A single centre retrospective case series of patients with telemetric sensor in LP shunt system, between 2015 and 2021, consisting of 5 patients. Review of indications for use, duration of function of telemetric sensor and associated complications. Results: There was no procedural complications of LP shunt insertion with telemetric sensor. The patient with highest body weight patient had retraction of distal tubing which required distal resiting 3 times. Four out of five patients had no complications. In all cases, telemetric sensor functioned satisfactorily with no dysfunction. The duration of documentation was 1-40 months. Pressure readings were satisfactorily carried out in variety of positions. Discussion and conclusion: This is the first report of telemetric sensor use in the lumbar theca. It can provide a valuable way of measuring cerebrospinal fluid pressures, particularly in patients avoiding cranial surgery. More research is indicated to assess what pressure values would mean clinically.