Aswin Chari

DESH negative normal pressure hydrocephalus: can patients still benefit from shunt insertion?

Selecting probable idiopathic normal pressure hydrocephalus (INPH) patients for shunt insertion presents a challenge because of coexisting comorbidities and other conditions that could mimic NPH. The characteristic appearance of DESH (Disproportionately Enlarged Subarachnoid Space Hydrocephalus) on brain imaging has been shown to have a high positive predictive value in identifying shunt responsive INPH patients (SINPHONI trial). However, the negative predictive value of this radiological sign was not clearly demonstrated.

Three-hundred cases of Spiegelberg ICP monitoring for hydrocephalus and CSF disorders: the Queen Square experience

Results ICPM was undertaken for a number of different conditions including undiagnosed headache (20.4%), IIH (28.7%), NPH (5.3%), high-pressure hydrocephalus (eg congenital/ post-traumatic/post-SAH) (17.2%) and Chiari malformations/syringomyelia (13.6%). Indications for ICPM included headache (74.0%), visual disturbance (6.2%), gait disturbance (6.2%) and cognitive disturbance (5.0%). Mean monitoring time was 37.3 hrs (range 12-154 hrs). Monitoring was conducted in the presence of a CSF shunt (50.6%), venous stent (3.7%) and previous cranial decompression (6.5%). Dynamic monitoring (eg with different shunt settings or pre/post venous stent insertion) was undertaken in 12.4%. Outcomes from ICPM included insertion of new CSF shunt (21.0%), revision of CSF shunt (13.0%), insertion of venous stent (6.5%), insertion of and lumbar drains for infusion studies (3.6%); importantly, non-operative treatment was pursued in a number of cases including shunt valve adjustment (7.7%) and conservative management (29.9%). Complications included superficial infection (4 patients, 1.2%), symptomatic intracerebral haematoma (1 patient, 0.3%) and misplacement (3 patients, 0.9%); importantly, there were no cases of deep intracranial infection and the only case of seizures was in the patient with the intracerebral haematoma. Conclusion This is the largest known series of ICPM for CSF disorders. It shows that ICP monitoring is a safe procedure and may be undertaken as part of routine protocol in the management of complex hydrocephalus patients. The number of cases that were subsequently managed conservatively or with a simple valve adjustment (37.6%) indicates the utility in terms of reducing operative interventions. Further evaluation of positive and negative predictive values based on the results of ICP monitoring and health-economic analyses will push the case for routine ICP monitoring prior to definitive management of all hydrocephalus patients.

Venous sinus stenting immediately reduces intracranial pressure in Idiopathic Intracranial Hypertension patients with venous sinus stenosis

Idiopathic Intracranial Hypertension (IIH) is characterised by an increased intracranial pressure (ICP) in the absence of any central nervous system disease or structural abnormality, and normal CSF composition. Management becomes complicated once surgical intervention is required. Venous sinus stenosis has been suggested as a possible aetiology for IIH. Venous sinus stenting has emerged as a possible interventional option. Evidence for venous sinus stenting is based on elimination of the venous pressure gradient and clinical response. There have been no studies demonstrating the immediate effect of venous stenting on ICP.

Intramuscular Local Anesthetic Infiltration at Closure for Postoperative Analgesia in Lumbar Spine Surgery: A Systematic Review and Meta-analysis

Study Design. Systematic Review and Meta-Analysis Objective. To identify whether intramuscular local anesthetic infiltration prior to wound closure was effective in reducing postoperative pain and facilitating early discharge following lumbar spine surgery. Summary of Background Data. Local anesthetic infiltration prior to wound closure may form part of the multimodal strategy for postoperative analgesia, facilitating early mobilization and discharge. Although there are a number of small studies investigating its utility, a quantitative meta-analysis of the data has never been performed. Methods. This review was conducted according the PRISMA statement and was registered with the PROSPERO database. Only randomized controlled trials were eligible for inclusion. Key outcomes of interest included time to first analgesic demand, total postoperative opiate usage in the first 24 hours, visual analogue score (VAS) at 1, 12 and 24 hours and postoperative length of stay. Results. Eleven publications fulfilled the inclusion criteria. A total of 438 patients were include; 212 in the control group and 226 in the intervention group. Local anesthetic infiltration resulted in a prolonged time to first analgesic demand (mean difference (MD) 65.88 minutes, 95% confidence interval (95% CI) 23.70 to 108.06, P.0.002) as well as a significantly reduced postoperative opiate demand (M.D. −9.71 mg, 95% CI −15.07, −4.34, p = 0.0004). There was a small but statistically significant reduction in postoperative visual analogue score (VAS) at 1 hour (M.D. −0.87 95%CI −1.55, −0.20, p = 0.01), but no significant reduction at 12 or 24 hours (p = 0.93 and 0.85 respectively). Conclusion. This systematic review and meta-analysis provides evidence that postoperative intramuscular local anaesthetic infiltration reduces postoperative analgesic requirements and the time to first analgesic demands for patients undergoing lumbar spine surgery. Key research priorities include optimization of the choice and strength of local anaesthetic agent and health-economic analyses to strengthen the case for routine use of postoperative local anesthetics in lumbar spine surgery. Level of Evidence: 1

Comorbidites in NPH - local introspective - ‘Shunt them all’!.

In response to the 2013 ISH-CSF task force review on comorbidities in NPH we assessed 73 patients who were diagnosed with NPH and underwent shunt surgery at our tertiary neurosurgical unit between August 2008 and August 2012.

Intracranial pressure and venous sinus pressure gradients: what happens 3 months after stenting?

Benign Intracranial hypertension (BIH) is commonly associated with venous sinus stenosis. Increasingly, this is treated endovascularly with stent insertion. However, this treatment modality is still controversial. Clinical improvement post stent insertion has been described. Little is known about long-term control of intracranial pressure (ICP). In our unit, catheter cerebral venogram with pressure measurements is routinely performed 3 months post stent insertion in BIH patients. We aim to quantify the degree of venous pressure changes in stenosis patients treated with sinus stenting and how the changes correlate with radiographic improvements.

Intracranial pressure in patients with papilloedema

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.

Differential compartment overdrainage syndrome

We describe a consistently similar clinical presentation of patients with complex hydrocephalus and encysted fourth ventricle separately drained by infratentorial shunt insertion.

Cerebral venous sinus stent insertion as a primary versus secondary procedure in the treatment of intracranial hypertension.

Venous sinus stent insertion is being increasingly used as a primary treatment for intracranial hypertension patients (BIH). However, the value of this treatment modality is still controversial. This study looks into the difference in effectiveness of stents inserted as a primary procedure and those inserted in patients who already had cerebrospinal fluid diverting shunt in place i.e. as a secondary procedure.

Learning to control ICP

The landmark discovery that control of autonomic physiology could be ‘learned’ using biofeedback was first demonstrated with heart rate [1,2]. Biofeedback control has since been demonstrated with physiological variables such as regional cerebral blood flow, and end tidal carbon dioxide, with therapeutic application in conditions including migraine and epilepsy [3-6]. Here, we demonstrate for the first time, learned control of intracranial pressure (ICP), in a single patient using biofeedback of simultaneous ICP recordings via a Speigelberg™ intracranial pressure monitor.