Chemical angioplasty vs. balloon plus chemical angioplasty for delayed cerebral ischemia: a pilot study of PbtO2 outcomes

BACKGROUND

Delayed cerebral ischaemia (DCI) is a major cause of morbidity and mortality after aneurysmal subarachnoid haemorrhage (aSAH). Chemical angioplasty (CA) and transluminal balloon angioplasty (TBA) are used to treat patients with refractory vasospasm causing DCI. Multi-modal monitoring including brain tissue oxygenation (PbtO2) is routinely used at this centre for early detection and management of DCI following aSAH. In this single-centre pilot study, we are comparing these two treatment modalities and their effects on PbtO2.

METHODS

Retrospective case series of patients with DCI who had PbtO2 monitoring as part of their multimodality monitoring and underwent either CA or TBA combined with CA. PbtO2 values were recorded from intra-parenchymal Raumedic NEUROVENT-PTO® probes. Data were continuously collected and downloaded as second-by-second data. Comparisons were made between pre-angioplasty PbtO2 and post-angioplasty PbtO2 median values (4 h before angioplasty, 4 h after and 12 h after).

RESULTS

There were immediate significant improvements in PbtO2 at the start of intervention in both groups. PbtO2 then increased by 13 mmHg in the CA group and 15 mmHg in the TBA plus CA group in the first 4 h post-intervention. This improvement in PbtO2 was sustained for the TBA plus CA group but not the CA group.

CONCLUSION

Combined balloon plus chemical angioplasty results in more sustained improvement in brain tissue oxygenation compared with chemical angioplasty alone. Our findings suggest that PbtO2 is a useful tool for monitoring the response to angioplasty in vasospasm.

Lumbosacral lipoma in childhood, how strong is the evidence base? A systematic review

OBJECTIVE

Conus region lumbosacral lipomas (LSLs) are highly heterogeneous in their morphology, clinical presentation, and outcome, with an incompletely understood natural history and often treacherous surgical anatomy. This systematic review aims to critically evaluate and assess the strength of the current LSL evidence base to guide management strategies.

METHODS

According to a systematic review following PRISMA guidelines, a search was conducted using the key term "lumbosacral lipoma" across MEDLINE (OVID), Embase, Cochrane Library, and PubMed databases from January 1951 to April 2021. All studies containing ten or more paediatric conus lipomas were included. Data heterogeneity and bias were assessed.

RESULTS

A total of 13 studies were included, containing 913 LSLs (predominantly transitional type-58.5%). Two-thirds (67.5%) of all patients (treated and non-treated) remained clinically stable and 17.6% deteriorated. Neuropathic bladder was present in 8.6% at final follow-up. Of patients managed surgically, near-total resection vs. subtotal resection deterioration-free survival rates were 77.2-98.4% and 10-67% respectively. 4.5% (0.0-27.3%) required re-do untethering surgery. Outcomes varied according to lipoma type. Most publications contained heterogeneous populations and used variable terminology. There was a lack of consistency in reported outcomes.

CONCLUSION

Amongst published series, there is wide variability in patient factors such as lipoma type, patient age, and methods of (particularly urological) assessment. Currently, there is insufficient evidence base upon which to make clear recommendations for the management of children with LSL. There is an imperative for neurosurgeons, neuroradiologists, and urologists to collaborate to better standardise the terminology, assessment tools, and surgical interventions for this challenging group of conditions.

Ventriculo-atrial shunt in idiopathic intracranial hypertension

PURPOSE

CSF diversion  is a recognised intervention in idiopathic intracranial hypertension (IIH), particularly in the presence of vision-threatening papilledema. Although ventriculo-atrial (VA) shunt insertion is a routine neurosurgical procedure, ventriculoperitoneal and lumboperitoneal shunts have been mostly used in this particular indication. This study aims to look at a single centre's experience with VA shunts in idiopathic intracranial hypertension (IIH).

METHODS

Retrospective case series with a review of electronic records over a 10-year period; exclusion criteria were duplication of same shunt insertion, no VA shunt insertion, paediatric patients and indication other than IIH. Notes were reviewed for demographics, shunt survival (defined by time prior to revision) and reasons for revision.

RESULTS

Eight VA shunt procedures were identified in 6 patients (mean age at insertion 34 ± 10 years) with a mean follow-up of 58 ± 25 months. All shunts were secondary procedures; 2 revisions from lumbo-pleural, 2 from ventriculopleural, 2 from ventriculoatrial and one each from ventriculoperitoneal and combined lumbo-/ventriculoperitoneal. At 50 months, 75% of VA shunts had survived, compared to only 58.3% of VPleural shunts in patients with IIH. Revisions were required due to acute intracranial bleed (1 case)-revised at day 1, and thrombus at distal site (1 case)-revised at day 57. Both shunts were later reinserted. From the latest clinic letters, all patients had their treatment optimised with this procedure, although only two patients had documented resolved papilloedema post-procedure.

CONCLUSIONS

Ventriculo-atrial shunts are a safe and efficacious alternative option for CSF diversion in IIH. In this series, only 1 shunt was revised for a VA shunt-specific complication.

Distal fusion in Duchenne scoliosis: the relevance of preoperative pelvic obliquity. A case series study

PURPOSE

The aim of this study was to determine clinical and radiographic outcomes for Duchenne Muscular Dystrophy (DMD) patients who underwent posterior spinal fusion from T2/3 to L5 (without pelvic fixation), at this single centre.

METHODS

From January 2012 to January 2020, 29 consecutive DMD scoliosis patients underwent posterior spinal fusion using pedicle screws from T2/3 to L5 in a single center with a minimum of 3 years follow-up (FU). Radiologic measurements and chart review were performed.

RESULTS

Twenty nine patients aged 14 ± 1.5 years were included. No patient was lost to FU. All patients had significant correction in Cobb angle, pelvic obliquity (PO) and lumbar lordosis (LL), without loss of correction at last FU. The mean values for preoperative, immediate postoperative and last FU were CA 62o, 15o and 17o, PO: 21o, 8o and 9o; and LL 10o, -41o and -41o respectively. Correction in CA was independent of any variable analysed including implant density, rod diameter, traction, or bone density. Regarding PO, it was inversely related to age and independent of all other variables. Factors associated with postoperative complications were age and respiratory function.

CONCLUSIONS

It appears from our results that pelvic fixation might not always be required in DMD scoliosis surgery, when using pedicle screws with lowest instrumented vertebra at L5. However, larger preoperative PO values can be related with residual PO. It seems that probably related to the underlying condition, early surgery may decrease incidence of complications.

LEVEL OF EVIDENCE

IV.

Resolution of Large Cervico-Thoracic Syringomyelia Following Treatment of Thyrotoxicosis: A Case Report

Treatment for a large symptomatic syrinx associated with a Chiari 1 is predominately surgical, via a foramen magnum decompression (FMD), with the aim to normalise cerebrospinal fluid (CSF) movement. Whilst theories of underlying hyperdynamic states in Chiari 1 and Syringomyelia exist, to date there is no effective medical treatment to reverse Syringomyelia. A 17-year-old female was referred with a seven-month history of gradually progressive impaired temperature sensation in her left upper limb. She had also been concomitantly diagnosed with thyrotoxicosis. Magnetic resonance imaging (MRI) confirmed a Chiari 1 with a large syrinx. The patient preferred to avoid surgery in the first instance. She underwent treatment for her thyrotoxicosis. The eight-month, 20- and 36-month follow-up MRI scans demonstrated a gradual resolution of the Chiari 1 malformation and the syrinx. Whilst there have been reports of Chiari 1 malformation association with hyperthyroidism, this is the first report describing syrinx resolution following treatment of thyrotoxicosis. Hyperdynamic circulation can result in syrinx formation through various mechanisms. We hypothesise that the treatment of thyrotoxicosis resulted in normalisation of CSF pulse amplitude and subsequent syrinx resolution. Hyperthyroidism evaluation may be explored in studies of CM1 and Syrinx or other CSF disorders.

Neurosarcoidosis Mimicking Normal Pressure Hydrocephalus

Two female patients, aged 46 and 51, were referred to the National Hospital for Neurology and Neurosurgery with symptoms resembling normal pressure hydrocephalus (NPH) and with ventriculomegaly on the MRI. Both had a definite diagnosis of neurosarcoidosis (NS) on biopsy, and they underwent the medical and surgical management reserved for NPH. At follow-up, their presenting symptoms had resolved and they had clinically improved. Neurosarcoidosis can mimic NPH, and it should be excluded in patients presenting with NPH.

A survival analysis of ventricular access devices for delivery of cerliponase alfa

OBJECTIVE

Late infantile neuronal ceroid lipofuscinosis type 2 (CLN2) is a rare autosomal recessive disease caused by tripeptidyl peptidase 1 enzyme deficiency. At the authors' center, the medication cerliponase alfa is administered every 2 weeks via the intracerebroventricular (ICV) route. This requires the placement of a ventricular access device (VAD) or reservoir and frequent percutaneous punctures of this device over the child's lifetime. In this study, the authors audited the longevity and survival of these VADs and examined the causes of device failure.

METHODS

A single-center survival analysis of VAD insertions and revisions (January 2014 through June 2020) was conducted. All children received cerliponase alfa infusions through a VAD. Patient characteristics and complications were determined from a prospectively maintained surgical database and patient records. For the VAD survival analysis, the defined endpoint was when the device was removed or changed. Reservoir survival was assessed using Kaplan-Meier curves and the log-rank (Cox-Mantel) test.

RESULTS

A total of 17 patients had VADs inserted for drug delivery; median (range) age at first surgery was 4 years 4 months (1 year 8 months to 15 years). Twenty-six VAD operations (17 primary insertions and 9 revisions) were required among these 17 patients. Twelve VAD operations had an associated complication, including CSF infection (n = 6) with Propionibacterium and Staphylococcus species being the most prevalent organisms, significant surgical site swelling preventing infusion (n = 3), leakage/wound breakdown (n = 2), and catheter obstruction (n = 1). There were no complications or deaths associated with VAD insertion. The median (interquartile range) number of punctures was 59.5 (7.5-82.0) for unrevised VADs (n = 17) versus 2 (6-87.5) for revised VADs (n = 9) (p = 0.70). The median survival was 301 days for revisional reservoirs (n = 9) versus 2317 days for primary inserted reservoirs (n = 17) (p = 0.019).

CONCLUSIONS

In the context of the current interest in intrathecal drug delivery for rare metabolic disorders, the need for VADs is likely to increase. Auditing the medium- to long-term outcomes associated with these devices will hopefully result in their wider application and may have potential implications on the development of new VAD technologies. These results could also be used to counsel parents prior to commencement of therapy and VAD implantation.

Does conus morphology have implications for outcome in lumbosacral lipoma?

OBJECTIVE

Lumbosacral lipomas (LSL) of the 'dorsal' type have been associated with more favourable outcomes compared with other conus region lipomas. We hypothesised that integrity of the conus on MRI underpins the improved prognosis in this subgroup of LSL patients.

METHODS

The definition of 'dorsal lipomas' included lipomas with attachment to the conus, but where the conus could be delineated on MRI (Morota type 1) as reported by Morota et al. (J Neurosurg Pediatr 19:428-439, 2017). Additional inclusion criteria included asymptomatic status at presentation, age >3 years at follow-up, and neurological and urological evaluation at presentation and at last follow-up. Lipoma extent and conus level were recorded. Outcome measures were the need for untethering surgery and neuro-urological status at last follow-up. Urological outcomes were defined by continence and efficacy of bladder emptying.

RESULTS

Twenty-six children were included (median age 8.7 years). Conus level was low (at or below L2) in 92%. Nine required untethering surgery: 5 prophylactic, 4 because of clinical deterioration. Twenty-five children were continent at last follow-up, one had stress incontinence, and none required catheterisation. One had persisting ankle weakness after surgery requiring orthotic support.

CONCLUSIONS

In LSL of the conus, visualisation of the conus on MRI is associated with good urological and motor outcomes. The integrity of the conus appears to be a more important prognostic factor than anatomical level. An observational approach to this group of LSL patients does not appear to compromise outcomes. These findings support a selective approach to untethering surgery.

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.

Accuracy of bolt external ventricular drain insertion by neurosurgeons of different experience

OBJECTIVE

The accuracy of tunneled external ventricular drain (EVD) placement has been shown to be similar among practitioners of varying experience, but this has not yet been investigated for bolt EVDs. Tunneled and bolt EVDs are distinct techniques, and it is unclear if conclusions regarding accuracy can be inferred from one method to the other. The goal of this study was to determine whether neurosurgical experience influences the accuracy of bolt EVD placement.

METHODS

We performed a single-center retrospective analysis of accuracy of bolt EVD placement between 1st December 2018 and 31st May 2020, comparing the accuracy outcomes between three levels of training (junior trainees (JT); mid-grade trainees (MT); senior trainees/fellows (ST)). Accuracy was determined radiologically by two methods: Kakarla grade and by measuring the distance of the catheter tip to its optimal position (DTOP) at the foramen of Monro.

RESULTS

Eighty-seven patients underwent insertion of bolt EVDs, of which n = 19 by JT, n = 40 by MT and n = 28 by ST, with a significant difference found between training grades in the median Kakarla grade (p = 0.0055) and in the accuracy of placement as per DTOP (p = 0.0168).

CONCLUSIONS

In contrast to previous published results on tunneled EVDs, we demonstrate that the accuracy of bolt EVD placement is dependent on neurosurgical experience. Our results draw awareness to the fact that the bolt EVD technique can represent a challenge for less experienced practitioners and underline the importance of dedicated training to support the safe insertion of bolt ventricular catheters.

Neuronavigation-assisted bedside placement of bolt external ventricular drains in the intensive care setting: a technical note

BACKGROUND

The insertion of bolt external ventricular drains (EVD) on the intensive care unit (ICU) has enabled rapid cranial cerebrospinal fluid (CSF) diversion. However, bolt EVDs tend to be perceived as a more challenging technique, particularly when dealing with small ventricles or when there is midline shift distorting the ventricular morphology. Furthermore, if neuronavigation guidance is felt to be necessary, this usually assumes a transfer to an operating theatre. In this technical note, we describe the use of electromagnetic neuronavigation for bolt EVD insertion on the ICU and assess the protocol's feasibility and accuracy.

METHODS

Case series of neuronavigation-assisted bolt EVD insertion in ICU setting, using Medtronic Flat Emitter for StealthStation EM.

RESULTS

Neuronavigation-guided bolt EVDs were placed at the bedside in n = 5 patients on ICU. Their widest frontal ventricular horn diameter in the coronal plane ranged from 11 to 20 mm. No procedural complications were encountered. Post-procedural CT confirmed the optimal placement of the EVDs.

CONCLUSIONS

Electromagnetic neuronavigation is feasible at the ICU bedside and can assist the insertion of bolt EVDs in this setting. The preference for a bolt EVD to be inserted in ICU-as is standard practice at this unit-should not prohibit patients from benefitting from image guidance if required.

Relationship between Brain Tissue Oxygen Tension and Transcranial Doppler Ultrasonography

BACKGROUND

Multimodal monitoring of intracranial pressure and brain tissue oxygen tension (PbtO₂) have been increasingly used to detect delayed cerebral ischemia (DCI) after subarachnoid hemorrhage. At our center, patients who cannot be easily assessed clinically will undergo intracranial pressure and PbtO₂ monitoring via a NEUROVENT-PTO bolt. We aimed to determine whether the Lindegaard ratios (LRs) computed from transcranial Doppler ultrasonography (TCDU) would correlate with, or can predict, the simultaneously recorded PbtO₂ value.

METHODS

Patients with aneurysmal subarachnoid hemorrhage, PbtO₂ recordings from the middle cerebral artery territory, and simultaneous TCDU scans available from the ipsilateral middle cerebral artery and internal carotid artery from August 2018 to 2019 were included in the present study. The index test result was vasospasm (LR of ≥3) found on TCDU. The reference standard was the presence of regional hypoxia (PbtO₂ <20 mm Hg). The PbtO₂ results were compared with those from computed tomography angiography as a radiological standard. The predictive values were calculated using a contingency table and receiver operating characteristic curve.

RESULTS

A total of 28 patients (6 men and 22 women; age, 59.04 ± 13.75 years) were identified with simultaneous brain tissue oxygen and TCDU recordings available. Of the 28 patients, 7 had cerebral hypoxia (PbtO₂ <20 mm Hg). We found no correlation between the PbtO₂ measurements and simultaneously recorded LRs (r² = 0.048; P = 0.26). A LR of ≥3 had high specificity (95.24%) for hypoxia but relatively low sensitivity (42.86%; P = 0.037).

CONCLUSION

We find TCDU to be specific for predicting cerebral hypoxia (measured via an intraparenchymal probe). Therefore, it could be a useful and noninvasive tool in the context of preventative DCI monitoring. However, given the low sensitivity, the lack of vasospasm on TCDU should not preclude the possibility of the presence of evolving DCI.

A Novel Neurosurgery Referral Course: Feasibility, Validation, and Inferences for Patient Care

OBJECTIVE

The speciality of neurosurgery is under-represented in the majority of medical school curriculums, and those rotating within this specialty tend to be those with career aspirations within this field. Consequently, few emergency medicine trainees are exposed to this specialty. The aim of this educational project was to develop and validate a neurosurgery referral course for the target audience of emergency medics.

DESIGN

Development of a single day neurosurgery referral course, developed with accreditation from the Royal College of Surgeons England. The curriculum covered commonly referred pathologies. Content validity was assessed using a 5-point Likert Scale. Median Likert scores were compared to "indifferent" (3) (indifferent = 3 in this study Likert scale) using the Wilcoxon matched-pairs signed-rank test. Construct validity was assessed using a standardized pre and postcourse 10-single best answer exam and results compared using paired t tests.

SETTING

A pilot "Neurosurgery for Emergency Medics" referral course, hosted at a single UK based neurosurgery unit.

PARTICIPANTS

A cohort of 19 delegates, working in emergency departments various regions within the UK.

RESULTS

The subjective feedback showed significantly higher than the expected median Likert scale satisfaction scores (p = 0.0001). Construct validity was confirmed, with significant improvement in proportion of students getting the answers in the single best answer exam after the days training course (p = 0.017).

CONCLUSIONS

We demonstrate feasibility, content, and construct validity and conclude that this pilot "Neurosurgery for Emergency Medics" course was beneficial. Integration of this 1-day course into local doctor's induction programmes for emergency medicine and neurosurgery may advance both local and national standards for referrals and consults alike, with the ultimate goal of improving patient care.

Interpretation of lumbar cerebrospinal fluid leukocytosis after cranial surgery: The relevance of aseptic meningitis

Raised white cell count (WCC) in lumbar CSF is a commonly used marker of meningitis. The effect of cranial neurosurgery per se on lumbar WCC is not established. At this single centre, many patients undergo ICPM followed by lumboperitoneal shunt (LPS), with lumbar CSF WCC samples taken during insertion. We aimed to determine the effect of ICP bolt insertion on lumbar CSF WCC. We undertook a retrospective analysis of lumbar CSF samples in patients who had recently undergone 24-h ICPM. Thirty-three patients (16F:7M) aged 43.31 ± 12.1 years (mean ± SD) had lumbar CSF samples after ICPM. Fourteen had CSF sampled within 6 weeks and 19 after 6 weeks of ICPM. Twenty-five samples were taken during LPS insertion, 5 during lumbar drainage/puncture and 3 during LPS revision. All 33 patients were afebrile at the point of CSF sampling. The mean lumbar WCC within 6 weeks of ICPM was significantly higher than the mean lumbar WCC after 6 weeks, being 15.4 ± 18.0 and 2.32 ± 1.79 cells/microlitre respectively respectively. There was no significant increase in RBC. In patients with raised CSF WCC, 60% of raised WCC were predominantly lymphoctyes and 40% predominantly neutrophils. Only one patient grew an organism (S. aureus). We conclude that lumbar CSF WCC can be raised following minor intracranial surgery, despite no clinical sign of infection. We caution against using lumbar CSF WCC values independently as the only marker of infection following neurosurgery.

Aspirin Preventing Occlusion after Coil Migration into the Distal Anterior Cerebral Artery

Endovascular coil embolization of cerebral aneurysm is a common procedure for managing cerebral aneurysms. We present a rare case of immediate silent coil migration into the pericallosal artery, without distal occlusion, following successful embolization. Despite the entire coil sitting within the lumen of the artery, good distal flow was observed. The patient remained asymptomatic throughout and had a good long-term (three years to date) outcome (modified Rankin Scale score of 1). We believe that the novel protective factor was the routine use of a single anti-platelet post-procedure.

Natural history of ventriculomegaly in adults: a cluster analysis

OBJECTIVE

Chronic ventriculomegaly in the absence of raised intracranial pressure (ICP) is a known entity in adult hydrocephalus practice. The natural history and indication for treatment is, however, poorly defined. A highly heterogeneous group, some adults with ventriculomegaly are asymptomatic, while others have life-threatening deteriorations. The authors hypothesized that the various presentations can be subtyped and represent different stages of decompensation. A cluster analysis was performed on a cohort of patients with chronic ventriculomegaly with the aim of elucidating typical clinical characteristics and outcomes in chronic ventriculomegaly in adults.

METHODS

Data were collected from 79 patients with chronic ventriculomegaly referred to a single center, including demographics, presenting symptoms, and 24-hour ICP monitoring (ICPM). A statistical cluster analysis was performed to determine the presence of subgroups.

RESULTS

Four main subgroups and one highly dissimilar group were identified. Patients with ventriculomegaly commonly have a perinatal event followed by one of four main presentations: 1) incidental ventriculomegaly with or without headache; 2) highly symptomatic presentation (including reduced consciousness) and raised ICP; 3) early presenting with symptoms of headache and nausea (with abnormal pulsatility); and 4) late presenting with features common to normal pressure hydrocephalus. Each symptomatic group has characteristic radiological features, ICPM, and responses to treatment.

CONCLUSIONS

Cluster analysis has identified subgroups of adult patients with ventriculomegaly. Such groups may represent various degrees of decompensation. Surgical interventions may not be equally effective across the subgroups, presenting an avenue for further research. The identified subtypes provide further insight into the natural history of this lesser studied form of hydrocephalus.

Approach to Slitlike Ventricles: Parietal-Occipital versus Frontal Burr Catheter Entry Sites

BACKGROUND

Slit ventricles can be a challenging target during shunt catheter insertion. Traditionally, the frontal approach has been considered optimal for small ventricles. At this center, routine use of electromagnetic (EM) stereotactic guidance (Stealth, Medtronic, Dublin, Ireland) has enabled a parietooccipital (P-O) 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 P-O approach versus frontal shunt.

METHODS

We studied a retrospective cohort of patients with slit ventricles and a ventricular shunt inserted using EM guidance between 2012 and 2018. Slitlike ventricles were defined as the widest point of the lateral ventricle <3 mm. Outcome measures included placement accuracy and survival using the Kaplan-Meier curve. Optimal final catheter tip location was considered to be the frontal horn of the ipsilateral lateral ventricle.

RESULTS

Eighty-two patients (77 female, 5 male) aged 34.9 ± 10.8 years (mean ± standard deviation) had ventricular shunts inserted for idiopathic intracranial hypertension (n = 63), chiari/syrinx (n = 8), congenital (n = 10), and pseudomeningocele (n = 1). Of those identified, 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 period. There was no significant different in shunt survival between the 2 approaches (P = 0.37).

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 2 approaches was similar.

The Evolution of the Role of External Ventricular Drainage in Traumatic Brain Injury

External ventricular drains (EVDs) are commonly used in neurosurgery in different conditions but frequently in the management of traumatic brain injury (TBI) to monitor and/or control intracranial pressure (ICP) by diverting cerebrospinal fluid (CSF). Their clinical effectiveness, when used as a therapeutic ICP-lowering procedure in contemporary practice, remains unclear. No consensus has been reached regarding the drainage strategy and optimal timing of insertion. We review the literature on EVDs in the setting of TBI, discussing its clinical indications, surgical technique, complications, clinical outcomes, and economic considerations.

Extradural Compressive Spinal Cerebrospinal Fluid Leak in Ehlers-Danlos Syndrome

Ehlers-Danlos syndrome can be associated with cerebrospinal fluid (CSF) disturbances including recurrent CSF leak and Chiari I malformations. Persistent pseudomeningoceles are known to be associated with raised intracranial pressure. We present an unusual case of a compressive epidural CSF collection occurring after a computed tomography-guided L5 nerve root block and describe an effective management strategy.

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.

Disproportionately Large Communicating Fourth Ventricle: Pearls for Diagnosis and Management

Introduction Disproportionately large communicating fourth ventricle (DLCFV) is an unusual presentation of communicating hydrocephalus, in which patients with hydrocephalus have a disproportionately enlarged fourth ventricle in the absence of obstructive pathology. We present six cases of DLCFV which, to date, is the largest series of this relatively rare condition. We highlight the significance of diagnosis and its differentiation from trapped fourth ventricle (TFV) and discuss the nuances for optimal management of DLCFV. Methods Retrospective case series of consecutive patients with DLCFV, managed by the senior author (LT) over a 10-year period. Results Six cases were identified, five of whom had previous posterior fossa surgery and one with previous encephalitis. All patients presented with cerebellar signs, the initial group had unsuccessful initial management with typical cerebrospinal fluid (CSF) diversion. Consistent symptom resolution was achieved by the application of negative CSF pressures via external ventricular drainage (EVD), maintained with subsequent ventriculopleural shunt (VPL), valveless lumbopleural shunt (LPS) or valveless ventriculoperitoneal shunt (VPS), or proceeding directly to a low-pressure system. Conclusions DLCFV is a diagnosis characterised by cerebellar dysfunction, with or without cranial nerve palsies, often in the setting of previous posterior fossa pathology. Optimal management relies on knowledge of this unique diagnostic entity, and use of an EVD at negative pressures to confirm symptomatic and radiological improvement prior to definitive treatment.

Superficial and Deep Skin Preparation with Povidone-Iodine for Ventriculoperitoneal Shunt Surgery : A Technical Note

Objective

Ventriculoperitoneal (VP) shunt surgery is a common and effective treatment for hydrocephalus and cerebrospinal fluid disorders. Infection remains a major cause of morbidity and mortality after a VP shunt. There is evidence that a deep skin flora microbiome may have a role to play in post-operative infections. In this technical note, we present a skin preparation technique that addresses the issue of the skin flora beyond the initial incision.

Methods

The patient is initially prepped, as standard, with. a single layer of 2% CHG+70% isopropyl alcohol. The novel stage is the ‘double incision’ whereby an initial superficial incision receives a further application of povidone-iodine prior to completing the full depth incision.

Results

Of the 84 shunts inserted using the double-incision method (September 2015 to September 2016), only one developed a shunt infection.

Conclusion

The double incision approach to skin preparation is a unique operative stage in VP shunt surgery that may have a role to play in reducing acute shunt infection.

Developing a pediatric neurosurgical training model

OBJECTIVE One of the greatest challenges of pediatric neurosurgery training is balancing the training needs of the trainee against patient safety and parental expectation. The traditional "see one, do one, teach one" approach to training is no longer acceptable in pediatric neurosurgery. The authors have developed the baby Modeled Anatomical Replica for Training Young Neurosurgeons (babyMARTYN). The development of this new training model is described, its feasibility as a training tool is tested, and a new approach of integrating simulation into day-to-day training is suggested. METHODS In part 1 (development), a prototype skull was developed using novel model-making methods. In part 2 (validation), 18 trainee neurosurgeons (at various stages in training) performed the following 4 different procedures: 1) evacuation of a posterior fossa hematoma; 2) pterional craniotomy; 3) tapping of the fontanelle to obtain a CSF specimen; and 4) external ventricular drain insertion. Completion of the procedural stages (scored using a curriculum-based checklist) was used to test the feasibility of babyMARTYN as a training tool. Likert scale-based questionnaires were used to assess the model for face and content validity. Training benefit was assessed using pre- and posttraining ratings on the Physician Performance Diagnostic Inventory Scale (PPDIS). To determine the significance of improvement in median PPDIS score, the Wilcoxon matched-pairs signed-rank test was performed. RESULTS In part 1 (development), the model was successfully developed with good fidelity. In part 2 (validation), the validation data demonstrated feasibility, face, and content validity. The PPDIS score significantly increased for all groups after babyMARTYN training, thereby indicating a potential future role for babyMARTYN in the training of pediatric neurosurgeons. CONCLUSIONS This recent collaborative neurosurgical development by the Royal College of Surgeons of England is designed to supplement current neurosurgical training. High-fidelity, portable, operation-specific models enable preoperative planning and have the potential to be used in an operating room environment prior to novel operations. A "see one, simulate one, do one" approach for pediatric neurosurgical training using babyMARTYN is suggested.

Transtentorial Distortion Syndrome: Consistent Complication Following Lateral and Fourth Ventricular Shunting in Adults

BACKGROUND

Complex hydrocephalus affecting lateral and fourth ventricles separately is occasionally managed with cerebrospinal fluid diversion via supratentorial and infratentorial ventricular catheters. The optimal configuration to reduce complications is currently unknown in adults. We describe a consistently similar clinical presentation of patients with complex hydrocephalus and a fourth ventricle separately drained by infratentorial shunt insertion.

METHODS

This was a retrospective single-center case series. Medical notes were reviewed for clinical presentation, brain imaging, and neurophysiologic tests results. All patients underwent intracranial pressure monitoring (ICPM). Outcomes were determined by ventricular appearance on brain imaging computed tomography and symptomatic improvements postoperatively.

RESULTS

Five adult patients referred to the hydrocephalus service had separate infratentorial and supratentorial shunt systems. A common clinical presentation was observed, including lower motor neuron facial palsy (confirmed with electrophysiology), ophthalmoplegia, dysarthria, impaired gait headache, and nausea. We refer to this as transtentorial distortion syndrome. Twenty-four-hour ICPM demonstrated clear low pressures. All patients underwent shunt revision connecting the transtentorial shunts via a Y-connector and the addition of a distal valve. All subjects had improved ventricular appearance on computed tomography scans post revision, and normalization of ICPM was observed. In the follow-up period of 6 months, no patient required further shunt revision.

CONCLUSION

To prevent transtentorial distortion syndrome, supratentorial and infratentorial shunt constructs in adults with encysted fourth ventricles should be similar to the shunt systems widely known in the pediatric population with Dandy-Walker syndrome (i.e., joint output to a single valve distal to the connection of the 2 proximal drainage catheters).

Idiopathic intracranial hypertension: 120-day clinical, radiological, and manometric outcomes after stent insertion into the dural venous sinus

OBJECTIVE Idiopathic intracranial hypertension (IIH) is commonly associated with venous sinus stenosis. In recent years, transvenous dural venous sinus stent (DVSS) insertion has emerged as a potential therapy for resistant cases. However, there remains considerable uncertainty over the safety and efficacy of this procedure, in particular the incidence of intraprocedural and delayed complications and in the longevity of sinus patency, pressure gradient obliteration, and therapeutic clinical outcome. The aim of this study was to determine clinical, radiological, and manometric outcomes at 3-4 months after DVSS in this treated IIH cohort. METHODS Clinical, radiographic, and manometric data before and 3-4 months after DVSS were reviewed in this single-center case series. All venographic and manometric procedures were performed under local anesthesia with the patient supine. RESULTS Forty-one patients underwent DVSS venography/manometry within 120 days. Sinus pressure reduction of between 11 and 15 mm Hg was achieved 3-4 months after DVSS compared with pre-stent baseline, regardless of whether the procedure was primary or secondary (after shunt surgery). Radiographic obliteration of anatomical stenosis correlating with reduction in pressure gradients was observed. The complication rate after DVSS was 4.9% and stent survival was 87.8% at 120 days. At least 20% of patients developed restenosis following DVSS and only 63.3% demonstrated an improvement or resolution of papilledema. CONCLUSIONS Reduced venous sinus pressures were observed at 120 days after the procedure. DVSS showed lower complication rates than shunts, but the clinical outcome data were less convincing. To definitively compare the outcomes between DVSS and shunts in IIH, a randomized prospective study is needed.