966 Implementation of Regional Scalp Blockade for Painless Removal of ICP Bolts: A Quality Improvement Project

Introduction

Intracranial pressure (ICP) monitoring through insertion of a bolt is a common neurosurgical procedure for diagnosing cerebrospinal fluid disorders. The first step of our quality improvement project identified ICP bolt removal the most painful part of the procedure. We implemented and tested the efficacy of a scalp nerve block for bolt removal.

Method

Two groups were identified: (A) receiving oral analgesia only and (B) receiving ipsilateral supraorbital and supratrochlear nerve blocks. We then retrospectively compared satisfaction ratings of insertion versus removal process for the two bolt types using a telephonic questionnaire

Results

Eighty-five patients had ICP bolts (32M:53F, mean age 42.7±16.0 SD). Fifty-four were removed with oral analgesia (A) and 31 with oral and regional anaesthesia (B). Removal experience was reported as worse for group A than for group B (p < 0.01). Most patients (66%) reported would have preferred local anesthetic during removal. No complications occurred from the block.

Conclusions

Regional nerve blocks are a safe and effective adjuvant for the painless removal of frontal ICP monitoring bolts. The final stage of the project was to implement nerve blocks as standard practice for bolt removal, to improve patient experience.

TM3-9 Neurosarcoidosis presenting with normal pressure hydrocephalus: case series

Objectives

Neurosarcoidosis is a rare condition with a high mortality. Early recognition of symptoms is important to enable prompt interventions. We report a case series of NS with ventriculomegaly that presented with symptoms resembling normal pressure hydrocephalus (NPH).

Design

Case series.

Subjects

Patients with ventriculomegaly on MR imaging and diagnosis of confirmed or probable NS.

Methods

Analysis of medical records for presenting clinical features, neuroradiology, intervention and clinical outcomes in patients with ventriculomegaly and confirmed or probable NS.

Results

Four patients (2M:2F) aged 49.0±3.01 years (mean ±SD) were identified. Three had definite NS and one probable. Three presented with gait disturbance and one with memory impairment. MR Imaging (with gadolinium) demonstrated ventriculomegaly with leptomeningeal enhancement. One patient underwent 24 hour ICPM, with a median ICP of 3.47 mmHg and pulse amplitude of 4.35 mmHg. CSF showed mild increase in chronic inflammatory cells in the absence of infection. Patients underwent medical management plus ventriculoperionteal shunt insertion (with adjustable valves set to 5 cm H2O and anti-siphon devices). There was a propensity for transient development of slit-like ventricles but without other features of over-drainage. All patients showed symptom improvement following CSF diversion at mean follow-up of 27 months.

Conclusions

NS can present similarly to NPH. Early combined treatment of CSF diversion and medical management is effective for symptom management.

TM3-8 Use of adjustable anti-gravity devices in NPH patients with delayed post-shunt deterioration

Objectives

A subset of idiopathic Normal Pressure Hydrocephalus (NPH) patients respond to VP shunt insertion temporarily. Adjustable anti-gravity devices are designed to control position-induced CSF drainage changes; we aim to assess to effect of using these devices to achieve controlled overdrainage in temporary shunt responders.

Design

A single-centre retrospective study of patients undergoing VP shunt valve revision from an adjustable differential pressure valve with fixed anti-siphon (ProGAV +Shuntassistant) to a system incorporating an adjustable anti-siphon valve (ProGAV +ProSA) (April 2013-April 2018).

Subjects

21 patients diagnosed with temporary shunt-responsive NPH who improved on high volume shunt reservoir tap (10M: 11F). Mean age at first VP shunt insertion was 74.5±7.87 years.

Methods

Medical records were retrospectively reviewed for demographics, interventions and clinical outcomes.

Results

Mean duration until revision with a ProSA valve was 31.5±16.8 months (mean ±SD). Mean follow up was 31.4±15.9 months. Of 20 patients with sufficient follow-up, 12 made objective improvements in walking and/or neuropsychological test outcome. 15 patients made subjective improvements in mobility or cognitive impairment.

Conclusions

VP shunting with adjustable differential pressure valves and fixed antigravity devices may not drain sufficient CSF for optimum management of low pressure hydrocephalus. Addition of adjustable anti-gravity devices at lower shunt settings in temporary shunt responders may improve outcome.

WP1-9 Treatment implications of parkinson’s disease in normal pressure hydrocephalus

Objectives

Patients with Parkinson’s disease (PD) presenting with worsening gait and ventriculomegaly could have underlying normal pressure hydrocephalus (NPH). We aim to identify features of concurrent PD and NPH, assess investigations and benefits of intervention.

Design

Single-centre retrospective cohort study of patients diagnosed with PD and NPH, presenting to neurosurgery between April 2004 – April 2018.

Subjects

24 patients (20M: 4F) with concurrent PD and NPH, mean age 74.5±6.49 years (mean ±SD). 22 patients were diagnosed with PD prior to NPH diagnosis.

Methods

Medical records were studied for demographics, symptoms, and response to ventriculoperitoneal (VP) shunting. Chi-square test was used to compare frequency of post-operative symptoms against a local database of NPH patients.

Results

All patients presented to neurosurgery with gait disturbances, 21/24 with cognitive impairment, and 18/24 with urinary incontinence. 19 patients underwent VP shunt insertion; 5 patients were not suitable having failed a lumbar drain trial. Patients with PD and NPH improved in walking test outcomes and in urinary continence similarly to other NPH patients. Cognitive impairment did not respond well to VP shunting in patients with concurrent PD, significantly less than NPH patients without PD (p<0.01).

Conclusions

Diagnosis of NPH in patients with PD is a complex clinical problem due to frequent overlap of symptoms. Benefits may be gained if this subset of patients do reach neurosurgical services and receive intervention.

P102 Shunting slit ventricles: a comparison of the parieto-occipital vs frontal approach

Objectives

Slit ventricles can be a challenging target during shunt catheter insertion. Traditionally, the frontal approach has been considered optimal. At this centre, routine use of electromagnetic (EM) stereotatic guidance (StealthTM, Medtronic) has enabled a parieto-occipital burr hole approach to the frontal horns. We compare shunt placement and revisions required for patients with slit ventricles who had shunts inserted via a parieto-occipital (P-O) approach vs. frontal shunt.

Design

Retrospective cohort.

Subjects

Patients with slit ventricles and a ventricular shunt inserted using EM guidance between 2012–2018.

Methods

Slit ventricles were defined as <3 mm (widest). Outcome measures included placement accuary and survival using Kaplan-Meier curve.

Results

82 patients (77F:5M) aged 34.9±10.8 years (mean ±SD) had shunts inserted for IIH (n=63), chiari/syrinx (n=8), congenital hydrocephalus (n=10), pseudomeningocoele (n=1). 35 had primary P-O shunts and 46 had frontal shunts. Overall, 94% of cases had the catheter tip sitting in the frontal horn. The P-O approach was just as accurate as the frontal approach. Eight P-O shunts and 9 frontal shunts required revision over a 60 month periods. There was no significant different in shunt survival between the two approaches (p=0.99).

Conclusions

EM guided placement has enabled the P-O approach to be as safe and with equivalent survival to frontal approach. The accuracy of shunt placement between the two approaches was equivocal.

P109 Experience of tunnelled vs. bolt EVDs on the intensive care unit

Objectives

The placement of an external ventricular drain (EVD) is a common neurosurgical operation that carries great benefit in acute hydrocephalus but is not without risk. In our centre, bolt EVDs (B-EVD) are being placed in favour of tunnelled EVDs (T-EVD). The former has allowed for urgent CSF diversion in ITU. We compared EVD survival and complication rates between the two types of EVDs.

Design

Single centre prospective case-cohort.

Subjects

Twenty-five patients with B-EVDs and thirty-four patients with T-EVDs.

Methods

Clinical notes and radiographic reports were collected before and after the placement of EVDs for patients in ITU between January 2017 and June 2018.

Results

Fourteen of the 25 B-EVDs were placed on ITU, of which 2 were under stealth guidance. All 34 T-EVDs were placed in theatre. Mean time to CSF access after decision for diversion was 134 min in the B-EVD group and 227 min in the T-EVD group (p<0.05). Mean survival was 35 days for B-EVDs and 29 days for T-EVDs (p<0.05). Eight T-EVDs went onto be replaced as B-EVDs due to retraction or infection. Complications including infection, detachment or retraction were higher in the T-EVD group at 32% compared to 20% in the B-EVD group.

Conclusions

Bolt EVDs have a lower frequency of complications and higher survival compared to tunnelled EVDs. Since B-EVDs require fewer resources they can be placed faster and on ITU.

WM1-7 Brain parenchymal oxygen monitoring in delayed cerebral ischaemia

Objectives

At this single centre, tri-modal monitoring of ICP, temperature and direct brain tissue oxygen tension (PbtO2) is used to guide management of delayed cerebral ischaemia (DCI). We describe our experience of PbtO2 monitoring and its relationship with symptoms of DCI, regional cerebral blood flow (rCBF, perfusion imaging), intra-arterial chemical angioplasty and CSF diversion.

Design

Prospective cohort.

Subjects

Patients with aSAH who underwent over 24 hours of multi-modal PbtO2, temperature and intracranial pressure (ICP) monitoring via a Raumedic NEUROVENT-PTO probe.

Methods

Longitudinal analysis of PbtO2 values, presented as mmHg (mean±SD).

Results

Analysis of 1392 hours of tri-modal monitoring in 13 SAH patients. PbtO2 decreases >50% consistently reproduced focal neurological deficit. Symptomatic PbtO2 values ranged from 12–20 mmHg. Of the six patients who had reduced rCBF, all had a mean PbtO2 <15 mmHg. Five patients underwent intra-arterial chemical angioplasty (10 mg Verapamil in 100 ml NaCl over 30–40 mins). PbtO2 increased by at least 30% for 3.4±0.47 hours. CSF diversion resulted in a sustained mean increase in PbtO2 of 7.6±2.94 mmHg over the first 5 min (p=0.034).

Conclusions

PbtO2 <15 mmHg may predict development of a clinical deficit. Chemical angioplasty resulted in a pronounced but short-lived increase in PbtO2. CSF diversion resulted in a persistent increase in PbtO2. PbtO2 targeted management may be a valuable addition to the clinicians’ arsenal against DCI.

Intracranial pressure in patients with papilloedema

OBJECTIVES

Papilloedema is a clinical manifestation of chronically raised intracranial pressure (ICP), often seen in idiopathic intracranial hypertension (IIH). However, the extent of intracranial hypertension required to produce papilloedema is not known. We compare ICP values in IIH patients who developed papilloedema and those who did not. We aim to identify a pathological ICP threshold predictive of the development of papilloedema in IIH patients.

MATERIALS AND METHODS

Single-centre cohort of IIH patients (2006-2016) who underwent 24-hour ICP monitoring (ICPM) and ophthalmology assessments, prior to intervention. Papilloedema was graded according to the Frisén scale. An unpaired t-test compared 24-hour ICPM between papilloedema and no-papilloedema groups. Fisher's exact test was used to determine predictive value of ICP.

RESULTS

Thirty-six patients with IIH (35 F: 1M), mean age 32.5 ± 9.49 years (mean ± SD) were included. Patients with papilloedema had a mean median 24-hour ICP of 10.4 ± 5.32 mm Hg (n = 25), significantly higher than the group without papilloedema 6.31 ± 3.30 mm Hg (n = 11) (P < .05). The papilloedema group were exposed to higher pressures (10 mm Hg) for 30 minutes or more. Using 24-hour median ICP of 10 mm Hg as a minimum cut-off predictive value gives a specificity = 91%, sensitivity = 48%, PPV = 92% and NPV = 44% of detecting papilloedema.

CONCLUSIONS

A 24-hour ICP of 10 mmHg or more is a good predictor for papilloedema and reflects a pathological threshold. The range varied widely suggesting papilloedema can occur at even lower pressures. These results are consistent with emerging evidence suggest that pathologically "high" 24 hours ICP is lower than previously quoted.

Elective ICP monitoring: how long is long enough?

BACKGROUND

Intracranial pressure monitoring is commonly undertaken to assess and manage acute patients following head injury. However, ICP monitoring can also be a useful diagnostic tool in the management of CSF dynamics in elective patients. To date, there is little published research to suggest how long these elective patients require ICP monitoring in order to gain an accurate picture of a patient's ICP dynamics. At the author's institution, a minimum of 48-h data collection is currently undertaken in patients with a suspected ICP abnormality.

METHODS

A retrospective audit was undertaken comparing overall median ICP and overall median pulse amplitude data at three time points, 24 h, 48 h and total time analysed (if longer than 48 h). Paired T-test was used to assess if there were statistically significant differences between 24-h versus 48-h monitoring and total duration of monitoring. All patients admitted over a 6-month period for ICPM who met the inclusion/exclusion criteria were included.

RESULTS

Eighteen patients met the criteria. Median age was 45.8 years, range 22-83 years, 12 female and 6 male. No complications were experienced as a result of ICPM. Diagnosis included NPH, IIH, suspected shunt malfunction and Chiari malformation. The results demonstrated that there is no statistical difference between 24 h and 48 h or longer for both overall median ICP and pulse amplitude.

CONCLUSION

The results of this study demonstrate that ICP monitoring of elective adult patients using a Spiegelberg intraparenchymal bolt for 24 h gives an accurate picture of a patient's ICP dynamics compared with longer periods of monitoring.