Diederik O. Bulters

Impairment of Cerebral Autoregulation Predicts Delayed Cerebral Ischemia After Subarachnoid Hemorrhage: A Prospective Observational Study

Background and Purpose— Delayed cerebral ischemia (DCI) is a recognized contributor to unfavorable outcome after subarachnoid hemorrhage (SAH). Recent data challenge the concept of vasospasm as the sole cause of ischemia and suggest a multifactorial process with dysfunctional cerebral autoregulation as a component. We tested the hypothesis that early autoregulatory failure, detected using near-infrared spectroscopy–based index, TOxa and transcranial Doppler–based index, Sxa, can predict DCI. Methods— In this prospective observational study we enrolled consecutive patients with aneurysmal SAH that occurred <5 days from admission. The primary end point was the occurrence of DCI within 21 days of ictus. The predictive value of autoregulatory disturbances detected in the first 5 days was assessed using univarate proportional hazards model and a multivariate model. Results— Ninety-eight patients were included. Univariate analysis demonstrated increased odds of developing DCI when early autoregulation failure was detected (odds ratio [OR], 7.46; 95% confidence interval [CI], 3.03–18.40 and OR, 4.52; 95% CI, 1.84–11.07 for Sxa and TOxa, respectively) but not TCD-vasospasm (OR, 1.36; 95% CI, 0.56–3.33). In a multivariate model Sxa and TOxa remained independent predictors of DCI (OR, 12.66; 95% CI, 2.97–54.07 and OR, 5.34; 95% CI, 1.25–22.84 for Sxa and TOxa, respectively). Conclusions— Disturbed autoregulation in the first 5 days after SAH significantly increases the risk of DCI. Autoregulatory disturbances can be detected using near-infrared spectroscopy and transcranial Doppler technologies.

The SILVER (Silver Impregnated Line Versus EVD Randomized trial): a double-blind, prospective, randomized, controlled trial of an intervention to reduce the rate of external ventricular drain infection.

BACKGROUND Cerebrospinal fluid (CSF) infections associated with external ventricular drain (EVD) placement attract major consequences. Silver impregnation of catheters attempts to reduce infection. OBJECTIVE To assess the efficacy of silver catheters against CSF infection. METHODS We performed a randomized, controlled trial involving 2 neurosurgical centers (June 2005 to September 2009). A total of 356 patients requiring an EVD were assessed for eligibility; 325 patients were enrolled and randomized (167 plain, 158 silver); 278 patients were analyzed (140 plain, 138 silver). The primary outcome measure was CSF infection as defined by organisms seen on Gram stain or isolated by culture. Secondary outcome measures included ventriculoperitoneal (VP) shunting. RESULTS There was a significant difference in infection risk between the 2 study arms: 21.4% (30/140) for plain catheters vs 12.3% (17/138) for silver catheters (P = .0427; 95% confidence interval [CI]: 1.015-3.713). Patients who had an EVD infection had more than double the risk of requiring a VP shunt compared with patients without an EVD infection (45.7% [21/46] vs 19.7% [45/229], respectively, P = .0002; 95% CI: 1.766-6.682). There was also a significant difference in VP shunt risk with infection: plain (55.2%; 16/29) vs the silver arm (29.4%; 5/17); P = .0244 (95% CI: 1.144-11.695). A multivariate analysis demonstrated that infection risk was increased by duration of EVD placement (odds ratio: 1.160), spontaneous intracranial hemorrhage (odds ratio 4.958) and decreased by silver catheters (odds ratio: 0.423). CONCLUSION The study provides Class I evidence that silver-impregnated catheters reduce CSF infection.

The Natural History of Cranial Dural Arteriovenous Fistulae With Cortical Venous Reflux-The Significance of Venous Ectasia

BACKGROUND: The quoted risk of hemorrhage from dural arteriovenous fistulae with cortical venous reflux varies widely, and the influence of angiographic grade on clinical course has not previously been reported. OBJECTIVE: To assess the risk of hemorrhage and the influence of angiographic grade on this risk, compared with known predictors of hemorrhage such as presentation. METHODS: Seventy-five fistulae with cortical venous reflux identified in our arteriovenous malformations clinic between 1992 and 2007 were followed up clinically, and their angiograms were reviewed. RESULTS: There were 8 hemorrhages in 90 years of follow-up. The annual incidence of hemorrhage before any treatment was 13%, and 4.7% after partial treatment, giving an overall incidence of 8.9% before definitive treatment. Borden and Cognard grades were poor discriminators of risk for lesions with the exception of Cognard type IV lesions. These lesions, characterized by venous ectasia, had a 7-fold increase in the incidence of hemorrhage (3.5% no ectasia vs 27% with ectasia). Patients presenting with hemorrhage (20%) or nonhemorrhagic neurological deficit (22%) had a higher incidence of hemorrhage than those with a benign presentation (4.3%), but this may be directly linked to the presence of venous ectasia. CONCLUSION: In this series untreated dural arteriovenous fistulae with cortical venous reflux had a 13% annual incidence of hemorrhage after diagnosis. There was a significant difference between those with and without venous ectasia. This should be confirmed by further studies, but probably defines a high-risk subgroup of patients that requires rapid intervention.

Surgical management of acute subdural haematomas: current practice patterns in the United Kingdom and the Republic of Ireland.

Abstract Introduction. Uncertainty remains as to the role of decompressive craniectomy (DC) for primary evacuation of acute subdural haematomas (ASDH). In 2011, a collaborative group was formed in the UK with the aim of answering the following question: “What is the clinical- and cost-effectiveness of decompressive craniectomy, in comparison with craniotomy for adult patients undergoing primary evacuation of an ASDH?” The proposed RESCUE-ASDH trial (Randomised Evaluation of Surgery with Craniectomy for patients Undergoing Evacuation of Acute Subdural Haematoma) is a multicentre, pragmatic, parallel group randomised trial of DC versus craniotomy for adult head-injured patients with an ASDH. In this study, we used an online questionnaire to assess the current practice patterns in the management of ASDH in the UK and the Republic of Ireland, and to gauge neurosurgical opinion regarding the proposed RESCUE-ASDH trial. Materials and methods. A questionnaire survey of full members of the Society of British Neurological Surgeons and members of the British Neurosurgical Trainees Association was undertaken between the beginning of May and the end of July 2012. Results. The online questionnaire was answered by 95 neurosurgeons representing 31 of the 32 neurosurgical units managing adult head-injured patients in the UK and the Republic of Ireland. Forty-five percent of the respondents use primary DC in at least 25% of patients with ASDH. In addition, of the 22 neurosurgical units with at least two Consultant respondents, only three units (14%) showed intradepartmental agreement regarding the proportion of their patients receiving a primary DC for ASDH. Conclusion. The survey results demonstrate that there is significant uncertainty as to the optimal surgical technique for primary evacuation of ASDH. The fact that the majority of the respondents are willing to become collaborators in the planned RESCUE-ASDH trial highlights the relevance of this important subject to the neurosurgical community in the UK and Ireland.

Proposal for establishment of the UK Cranial Reconstruction Registry (UKCRR).

Abstract Background. The increasing utilisation of decompressive craniectomy for traumatic brain injury and stroke has led to an increase in the number of cranioplasties undertaken. Cranioplasty is also undertaken following excision of tumours originating from or invading the skull vault, removal of bone flaps due to post-operative infection, and decompressive craniectomy for the management of rarer causes of brain oedema and/or refractory intracranial hypertension. The existing literature which mainly consists of single-centre, retrospective studies, shows a significant variation in practice patterns and a wide range of morbidity. There also exists a need to measure the outcome as perceived by the patients themselves with patient reported outcome measures (PROMs; functional outcome, quality of life, satisfaction with cosmesis). In the UK, the concept of long-term surveillance of neurosurgical implants is well established with the UK shunt registry. Based on this background, we propose to establish the UK Cranial Reconstruction Registry (UKCRR). Aim. The overarching aim of the UKCRR is to collect high-quality data about cranioplasties undertaken across the UK and Ireland in order to improve outcomes for patients. Methods. Any patient undergoing reconstruction of the skull vault with autologous bone, titanium, or synthetic material in participating units will be eligible for inclusion. Data will be submitted directly by participating units to the Outcome Registry Intervention and Operation Network secure platform. A Steering Committee will be responsible for overseeing the strategic direction and running of the UKCRR. Outcome measures. These will include re-operation due to a cranioplasty-related issue, surgical site infection, re-admission due to a cranioplasty-related issue, unplanned post-operative escalation of care, adverse events, length of stay in admitting unit, destination at discharge from admitting unit, mortality at discharge from admitting unit, neurological status and PROMs during routine follow-up. Conclusion. The UKCRR will be an important pillar in the ongoing efforts to optimise the outcomes of patients undergoing cranioplasty.

Placement of silicone sheeting at decompressive craniectomy to prevent adhesions at cranioplasty

Adhesion formation between dura mater and cortex, and the overlying temporalis muscle and galea following decompressive craniectomy, can make subsequent cranioplasty difficult and adds to the risks of the procedure. We describe the implantation of sterile silicone sheeting at decompressive craniectomy to prevent adhesion formation and facilitate subsequent cranioplasty, potentially reducing surgical time, improving outcome and reducing risk.

Heme–Hemopexin Scavenging Is Active in the Brain and Associates With Outcome After Subarachnoid Hemorrhage

Background and Purpose— Long-term outcome after subarachnoid hemorrhage (SAH) is potentially linked to cytotoxic heme. Free heme is bound by hemopexin and rapidly scavenged by CD91. We hypothesized that heme scavenging in the brain would be associated with outcome after hemorrhage. Methods— Using cerebrospinal fluid and tissue from patients with SAH and control individuals, the activity of the intracranial CD91–hemopexin system was examined using ELISA, ultrahigh performance liquid chromatography, and immunohistochemistry. Results— In control individuals, cerebrospinal fluid hemopexin was mainly synthesized intrathecally. After SAH, cerebrospinal fluid hemopexin was high in one third of cases, and these patients had a higher probability of delayed cerebral ischemia and poorer neurological outcome. The intracranial CD91–hemopexin system was active after SAH because CD91 positively correlated with iron deposition in brain tissue. Heme–hemopexin uptake saturated rapidly after SAH because bound heme accumulated early in the cerebrospinal fluid. When the blood–brain barrier was compromised after SAH, serum hemopexin level was lower, suggesting heme transfer to the circulation for peripheral CD91 scavenging. Conclusions— The CD91–heme–hemopexin scavenging system is important after SAH and merits further study as a potential prognostic marker and therapeutic target.

External ventricular drainage: Is it time to look at national practice?

Aimun A. B. Jamjoom 1 , Angelos G. Kolias 2 , Malik Zaben 3 , Aswin Chari 2 , John Kitchen 4 , Alexis Joannides 2 , Paul M. Brennan 1 , Jothy Kandasamy 1 , Silvia Gatscher 5 , William P. Gray 3 , Michael D. Jenkinson 4 , Diederik O. Bulters 6 , Conor L. Mallucci 7 , Helmut Schuster 8 , Peter J. Hutchinson 2 & Aminul I. Ahmed 6 ; UK Neurosurgical Research Network & British Neurosurgical Trainee Research Collaborative

Recovery of oculomotor nerve palsy secondary to posterior communicating artery aneurysms

Abstract Background. Recent studies suggest more favourable recovery of oculomotor nerve palsy (ONP) caused by posterior communicating artery (PComA) aneurysms with microsurgical clipping compared to endovascular coiling. We describe a consecutive series of patients with ONP from PComA aneurysms treated by microsurgical clipping or endovascular coiling. Methods. We retrospectively reviewed medical records of all patients from 2005 to 2009 with complete or partial ONP from PComA aneurysms. Results. Twenty patients were identified, three with unruptured aneurysms. Two patients with ruptured aneurysms were unfit for treatment and therefore excluded. Of the 18 patients included (15 female), 9 underwent microsurgical clipping and 9 received endovascular coiling. Patients treated by surgical clipping were significantly younger compared to those treated by endovascular coiling (mean 52.3 vs. 67.9 years; p = 0.039). Five patients had incomplete ONP (3 clipped, 2 coiled) and thirteen had complete ONP. At 6 months, six of nine patients treated with clipping and five of nine patients treated with coiling had complete resolution of their ONP (p = 1.0); the remainder had partial improvement. There was no significant difference in duration of pre-treatment ONP, age, sex or status of aneurysm (ruptured or unruptured) between patients in the two groups or between those with full or partial recovery. However, all 5 patients with incomplete ONP at presentation recovered fully, compared with 6 of 13 patients who presented with complete ONP. Conclusions. We found no significant difference between clipping and coiling in the recovery of ONP due to PComA aneurysms. Patient who present with incomplete ONP are more likely to have a full recovery of ONP following either treatment modality than those who present with complete ONP.

A Randomized Controlled Trial of Prophylactic Intra-aortic Balloon Counterpulsation in High-Risk Aneurysmal Subarachnoid Hemorrhage

Background and Purpose— To assess whether prophylactic postoperative intraaortic balloon counterpulsation (IABC) reduces the risk of poor outcome because of vasospasm following aneurysmal subarachnoid haemorrhage relative to conventional hypervolemic therapy (HT). Methods— This was a single-center, parallel group randomized controlled trial. Patients suffering a subarachnoid hemorrhage at high risk of vasospasm were eligible. Patients were randomly allocated to receive prophylactic IABC (n=35) or HT (n=36). The primary end point was Glasgow Outcome and SF-36 scores assessed at 6 months by a blinded and independent observer and analyzed by intention to treat. Secondary analysis of physiological parameters was by treatment performed. Results— Twenty-seven patients in each arm had a good outcome (P=0.55). There was no statistical difference in mean SF-36 score (t=0.39, P=0.70). There were no long-term complications secondary to IABC. There were no differences in preload (pulmonary artery wedge pressure, P=0.97) or afterload (mean arterial pressure, P=0.97). IABC was associated with a lower cardiac output (P=0.002) and higher systemic vascular resistance (P=0.005), although for both groups mean cardiac output was >6 L/min. Cerebral blood flow was not different between groups: HT=41.5 (SD 7.2), IABP=44.9 (SD 8.6) mL/100 g/min (P=0.14). Conclusions— In this study, prophylactic IABC did not improve perfusion indices or confer any clinical benefit following subarachnoid haemorrhage in patients with normal cardiac function. The study was small, however, and cannot be extrapolated to patients with cardiac failure and medically refractory symptomatic cerebral vasospasm. Clinical Trial Registration— This trial was not registered because enrolment began prior to July 1, 2005.