Anatomy and physiology of cisternostomy

Invasive Preoperative Investigations in Idiopathic Normal Pressure Hydrocephalus: A Comprehensive Review

Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder characterized by the triad of gait disturbance, cognitive impairment, and urinary incontinence. The condition is diagnosed mainly in older adults and is associated with ventricular enlargement without an increase in cerebrospinal fluid pressure. The clinical assessment involves a detailed medical history, physical examination, and cognitive testing. Neuroimaging is an essential part of the diagnostic workup for iNPH. However, to determine the suitability of patients for shunt surgery, a range of invasive preoperative investigations are employed. This narrative review aims to provide a comprehensive analysis of the current literature on invasive preoperative investigations in iNPH, focusing primarily on the lumbar infusion test, cerebrospinal fluid drainage tests, and continuous intracranial pressure monitoring. The strengths and limitations of each method, as well as their potential impact on treatment outcomes, are discussed.

Is basal cisternostomy in traumatic brain injury a need of hour or white elephant - A randomized trial to answer

Background

Basal cisternostomy (BC) recently emerged as an adjuvant/alternative procedure to decompressive craniectomy (DC) in traumatic brain injuries (TBIs) with its potential to effectively reduce both intracranial pressure (ICP) and brain edema. However, its role in TBI is not yet established in the true sense and with clarity. The objective of the present study was to evaluate the effect of adjuvant BC on ICP, mortality, and clinicoradiological outcome.

Methods

A single-center randomized control trial was conducted. Fifty patients were assigned to each DC-group and DC+BC-group. Randomization was done using the sealed envelope method. Both groups were followed in the postoperative period to compare the impact of surgery on ICP, radiological changes, and clinical outcome (mortality, days on ventilator/in intensive care unit (ICU), and Glasgow outcome scale-extended (GOS-E) at 12 weeks).

Results

Both groups were comparable in terms of preoperative clinicoradiological characteristics. On postoperative days 1, 2, and 3, mean ICP was significantly low in the DC+BC-group (P < 0.0001). The decline in ICP in the DC+BC-group was significant in both moderate and severe TBI patients. In comparison, DC+BC-group has a shorter duration of mechanical ventilation/ICU stay and significantly better GOS-E score at 12 weeks (P < 0.0001*). The mortality rate was less in the DC+BC-group (48%) as compared to the DC-group (64%). Among radiological features, mean midline shift and mean outward brain herniation were significantly less in the DC+BC group. Bone-flap replacement was possible in ten patients of DC+BC-group at the time of primary surgery.

Conclusion

Results of our study indicated that BC is beneficial in reducing both ICP and brain edema, which translates into favorable clinicoradiological outcomes.

Hypothermia impairs glymphatic drainage in traumatic brain injury as assessed by dynamic contrast-enhanced MRI with intrathecal contrast

Introduction

The impact of hypothermia on the impaired drainage function of the glymphatic system in traumatic brain injury (TBI) is not understood.

Methods

Male Sprague-Dawley rats undergoing controlled cortical impact injury (CCI) were subjected to hypothermia or normothermia treatment. The rats undergoing sham surgery without CCI were used as the control. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with intrathecal administration of low- and high-molecular-weight contrast agents (Gd-DTPA and hyaluronic acid conjugated Gd-DTPA) was performed after TBI and head temperature management. The semiquantitative kinetic parameters characterizing the contrast infusion and cleanout in the brain, including influx rate, efflux rate, and clearance duration, were calculated from the average time-intensity curves.

Results and discussion

The qualitative and semiquantitative results of DCE-MRI obtained from all examined perivascular spaces and most brain tissue regions showed a significantly increased influx rate and efflux rate and decreased clearance duration among all TBI animals, demonstrating a significant impairment of glymphatic drainage function. This glymphatic drainage dysfunction was exacerbated when additional hypothermia was applied. The early glymphatic drainage reduction induced by TBI and aggravated by hypothermia was linearly related to the late increased deposition of p-tau and beta-amyloid revealed by histopathologic and biochemical analysis and cognitive impairment assessed by the Barnes maze and novel object recognition test. The glymphatic system dysfunction induced by hypothermia may be an indirect alternative pathophysiological factor indicating injury to the brain after TBI. Longitudinal studies and targeted glymphatic dysfunction management are recommended to explore the potential effect of hypothermia in TBI.

The positive impact of cisternostomy with cisternal drainage on delayed hydrocephalus after aneurysmal subarachnoid hemorrhage

BACKGROUND

Hydrocephalus is one of the major complications of aneurysmal subarachnoid haemorrhage (aSAH). In the acute setting, an external ventricular drain (EVD) is used for early management. A cisternal drain (CD) coupled with the micro-surgical opening of basal cisterns can be an alternative when the aneurysm is clipped. Chronic hydrocephalus after aSAH is managed with ventriculo-peritoneal (VP) shunt, a procedure associated with a wide range of complications. The aim of this study is to analyse the impact of micro-surgical opening of basal cisterns coupled with CD on the incidence of VP shunt, compared to patients treated with EVD.

METHODS

The authors conducted a retrospective review of 89 consecutive cases of patients with aSAH treated surgically and endovascularly with either EVD or CD between January 2009 and September 2021. Patients were stratified into two groups: Group 1 included patients with EVD, Group 2 included patients with CD. Subgroup analysis with only patients treated surgically was also performed. We compared their baseline characteristics, clinical outcomes and shunting rates.

RESULTS

There were no statistically significant differences between the two groups in terms of epidemiological characteristics, WFNS score, Fisher scale, presence of intraventricular hemorrhage (IVH), acute hydrocephalus, postoperative meningitis or of clinical outcomes at last follow-up. Cisternostomy with CD (Group 2) was associated with a statistically significant reduction in VP-shunt compared with the use of an EVD (Group 1) (9.09% vs 53.78%; p < 0.001). This finding was confirmed in our subgroup analysis, as among patients with a surgical clipping, the rate of VP shunt was 43.7% for the EVD group and 9.5% for the CD group (p = 0.02).

CONCLUSIONS

Cisternostomy with CD may reduce the rate of shunt-dependent hydrocephalus. Cisternostomy allows the removal of subarachnoid blood, thereby reducing arachnoid inflammation and fibrosis. CD may enhance this effect, thus resulting in lower rates of chronic hydrocephalus.

Microneurosurgical anatomy of the basal cisterns: A brief review for cisternostomy

Background

Cisternostomy is a surgical technique thought of and developed as an option for severe brain trauma treatment. It demands a particular knowledge and skill to microsurgically approach basal cisterns and effectively manipulate their contents. To perform this procedure safely, the anatomy and pathophysiology must be clearly understood.

Methods

Detailed microscopic dissection and anatomical review were done, after a detailed reading of facts and recent publications about cisternostomy. Cisternal pathways and landmark planning are described and augmented using a new method to show de arachnoid borders. Finally, a brief discussion is written as a synopsis.

Results

Cisternostomy requires thorough microscopic knowledge and microsurgical skills. This paper intends to provide information to understand better the anatomy related, thus, easing the learning curve. The technique used to show arachnoid borders, complementing cadaveric and surgical images, was useful for this purpose.

Conclusion

To perform this procedure safely, it is mandatory to handle microscopic details of cistern anatomy. Reaching a core cistern is necessary to assure effectiveness. This procedure needs, as well, surgical step-by-step landmark planning and performing. Cisternostomy could be a life-saving procedure and a new powerful tool for severe brain trauma treatment. Evidence is being collected to support its indications.

Hypothermia reduces glymphatic transportation in traumatic edematous brain assessed by intrathecal dynamic contrast-enhanced MRI

The glymphatic system has recently been shown to clear brain extracellular solutes and can be extensively impaired after traumatic brain injury (TBI). Despite hypothermia being identified as a protective method for the injured brain via minimizing the formation of edema in the animal study, little is known about how hypothermia affects the glymphatic system following TBI. We use dynamic contrast-enhanced MRI (DCE-MRI) following cisterna magna infusion with a low molecular weight contrast agent to track glymphatic transport in male Sprague-Dawley rats following TBI with hypothermia treatment and use diffusion-weighted imaging (DWI) sequence to identify edema after TBI, and further distinguish between vasogenic and cytotoxic edema. We found that hypothermia could attenuate brain edema, as demonstrated by smaller injured lesions and less vasogenic edema in most brain subregions. However, in contrast to reducing cerebral edema, hypothermia exacerbated the reduction of efficiency of glymphatic transportation after TBI. This deterioration of glymphatic drainage was present brain-wide and showed hemispherical asymmetry and regional heterogeneity across the brain, associated with vasogenic edema. Moreover, our data show that glymphatic transport reduction and vasogenic edema are closely related to reducing perivascular aquaporin-4 (AQP4) expression. The suppression of glymphatic transportation might eliminate the benefits of brain edema reduction induced by hypothermia and provide an alternative pathophysiological factor indicating injury to the brain after TBI. Thus, this study poses a novel emphasis on the potential role of hypothermia in managing severe TBI.

Outcomes and Predictors of Outcome with Cisternostomy in the Management of Traumatic Brain Injury—A Prospective Observational Study at Tertiary Centre

Background Traumatic brain injury (TBI) is a major cause of morbidity and mortality in young individuals. Goal of management in TBI patients is mainly focused on the secondary injury. Since the cisterns and the brain communicate, it would be possible to decrease the pressure in both these compartments by opening the cisterns to the atmospheric pressure.

Objective To study the outcomes and predictors of outcome with cisternostomy in the management of TBI.

Methods A single tertiary care center's prospective observational study of outcomes with cisternostomy with intraoperative intracranial pressure (ICP) monitoring. Patients were evaluated clinically and radiologically with Marshall CT score. They were categorized into mild, moderate, and severe head injury groups based on Glasgow coma scale (GCS) score. Outcomes were evaluated with Glasgow outcome scale (GOS) score.

Results A total of 25 patients with TBI were enrolled in this study. They underwent cisternostomy with intraoperative ICP monitoring. They were categorized into 4 groups based on the age. In our study, mortality rate was 32%. As much as 48% had good recovery at 3 months follow-up with GOS 4 and 5. Mean ICP after cisternostomy was 6.36 ± 1.91 mm Hg. In our study, there was decrease in ICP after cisternostomy.

Conclusion Age, time interval from trauma to surgery, and ICP showed prognostic importance on outcomes. Cisternostomy can efficiently decrease the ICP in the TBI patients and reduce postoperative complications.

Basal cisternostomy for traumatic brain injury: A case report of unexpected good recovery

In subarachnoid hemorrhage following traumatic brain injury (TBI), the high intracisternal pressure drives the cerebrospinal fluid into the brain parenchyma, causing cerebral edema. Basal cisternostomy involves opening the basal cisterns to atmospheric pressure and draining cerebrospinal fluid in an attempt to reverse the edema. We describe a case of basal cisternostomy combined with decompressive craniectomy. A 35-year-old man with severe TBI following a road vehicle accident presented with acute subdural hematoma, Glasgow coma scale score of 6, fixed pupils and no corneal response. Opening of the basal cisterns and placement of a temporary cisternal drain led to immediate relaxation of the brain. The patient had a Glasgow coma scale score of 15 on postoperative day 6 and was discharged on day 10. We think basal cisternostomy is a feasible and effective procedure that should be considered in the management of TBI.

The Mini-Spheno-Supraorbital Craniotomy for Treatment of Ruptured Anterior Circulation Aneurysms

Objective:Yasargil introduced the pterional approach mainly for clipping of anterior circulation (AC) aneurysms. We implemented the mini-spheno-supraorbital (MSS) craniotomy, changing the shape and reducing the size of the classical pterional craniotomy. The literature on clipping ruptured AC aneurysms through reduced-in-size craniotomies is sparse. This study aims to describe the technique and present our experience in clipping ruptured AC aneurysms through the MSS approach. Materials and methods: The MSS craniotomy was used in 114 cases of clipping ruptured AC aneurysms. A single burr hole was placed at the "keyhole" and an ellipsoid bone flap in the spheno-supraorbital region was raised. The tabula interna was thinned circumferentially, the roof of the orbit was flattened. Among aneurysm clipping, the lamina terminalis and the subarachnoid basal cisterns were opened. The imaging modality, the severity of the subarachnoid hemorrhage (SAH) according to Hunt & Hess (H&H), the size of the bone flap, the surgery duration and the aneurysm obliteration rate seen at the postoperative DSA were examined. Results:Out of all patients in the study, 71% had exclusively CT-angiogram as initial imaging and suffered low-grade (H&H I°) SAH (71%). The mean size of the bone flap was 1.6 x 4.5 cm (1.3 x 4.3 - 2 x 8.5 cm). The approach allowed adequate 360°-dissection, sufficient proximal and distal control, brain relaxation though laminoterminotomy and opening of the basal cisterns. The mean duration from skin incision to clip application was 130 minutes (64-236 mins). Total obliteration rate was 97.3%. Conclusion:The MSS craniotomy is feasible in terms of safety and speed for clipping of ruptured AC aneurysms especially in lower-grade SAH.

Cisternostomy for malignant middle cerebral artery infarction: proposed pathophysiological mechanisms and preliminary results

BACKGROUND

The ischaemic stroke of the territory of the middle cerebral artery represents an event burdened by high mortality and severe morbidity. The proposed medical treatments do not always prove effective. Decompressive craniectomy allows the ischaemic tissue to shift through the surgical defect rather than to the unaffected regions of the brain, thus avoiding secondary damage due to increased intracranial pressure. In this study, we propose a novel treatment for these patients characterised by surgical fenestration of the cisterns of the skull base.

METHODS

We have treated 16 patients affected by malignant middle cerebral artery ischaemia and treated with cisternostomy between August 2018 and December 2019. The clinical history, neurological examination findings and neuroradiological studies (brain CT, CT angiography, MRI) were performed to diagnose stroke. Clinical examination was recorded on admission and preoperatively using the Glasgow Coma Scale and the National Institutes of Health Stroke Scale.

RESULTS

The study included 16 patients, 10 males and 6 females. The mean age at surgery was 60.1 years (range 19-73). Surgical procedure was performed in all patients. The patients underwent immediate postoperative CT scan and were in the early hours evaluated in sedation window. In total, we recorded two deaths (12.5%). A functional outcome between mRS 0-3, defined as favourable, was observed in 9 (64.2%) patients 9 months after discharge. A functional outcome between mRS 4-6, defined as poor, was observed in 5 (35.7%) patients 9 months after discharge.

CONCLUSIONS

The obtained clinical results appear, however, substantially overlapping to decompressive craniectomy. Cisternostomy results in a favourable functional outcome after 9 months. This proposed technique permits that the patient no longer should be undergone cranioplasty thus avoiding the possible complications related to this procedure. The results are certainly interesting but higher case numbers are needed to reach definitive conclusions.

Therapeutic Approaches for Cerebrovascular Dysfunction After Aneurysmal Subarachnoid Hemorrhage: An Update and Future Perspectives

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe subtype of stroke occurring at a relatively young age with a significant socioeconomic impact. Treatment of aSAH includes early aneurysm exclusion, intensive care management, and prevention of complications. Once the aneurysm rupture occurs, blood spreading within the subarachnoid space triggers several molecular pathways causing early brain injury and delayed cerebral ischemia. Pathophysiologic mechanisms underlying brain injury after aSAH are not entirely characterized, reflecting the difficulties in identifying effective therapeutic targets for patients with aSAH. Although the improvements of the last decades in perioperative management, early diagnosis, aneurysm exclusion techniques, and medical treatments have increased survival, vasospasm and delayed cerebral infarction are associated with high mortality and morbidity. Clinical practice can rely on a few specific therapeutic agents, such as nimodipine, a calcium-channel blocker proved to reduce severe neurologic deficits in these patients. Therefore, new pharmacologic approaches are needed to improve the outcome of this life-threatening condition, as well as a tailored rehabilitation plan to maintain the quality of life in aSAH survivors. Several clinical trials are investigating the efficacy and safety of emerging drugs, such as magnesium, clazosentan, cilostazol, interleukin 1 receptor antagonists, deferoxamine, erythropoietin, and nicardipine, and continuous lumbar drainage in the setting of aSAH. This narrative review focuses on the most promising therapeutic interventions after aSAH.

The Rise of Inflow Cisternostomy in Resource-Limited Settings: Rationale, Limitations, and Future Challenges

Low- and middle-income countries (LMICs) bear most of the global burden of traumatic brain injury (TBI), but they lack the resources to address this public health crisis. For TBI guidelines and innovations to be effective, they must consider the context in LMICs; keeping this in mind, this article will focus on the history, pathophysiology, practice, evidence, and implications of cisternostomy. In this narrative review, the author discusses the history, pathophysiology, practice, evidence, and implications of cisternostomy. Cisternostomy for the management of TBI is an innovation developed in LMICs, primarily for LMICs. Its practice is based on the cerebrospinal fluid shift edema theory that attributes injury to increased pressure within the subarachnoid space due to subarachnoid hemorrhage and subsequent dysfunction of glymphatic drainage. Early reports of the technique report significant improvements in the Glasgow Outcome Scale, lower mortality rates, and shorter intensive care unit durations. Most reports are single-center studies with small sample sizes, and the technique requires experience and skill. These limitations have led to criticisms and slow adoption of the technique. Further research is needed to establish the effect of cisternostomy on TBI outcomes.

Putting 'CSF-Shift Edema' Hypothesis to Test: Comparing Cisternal and Parenchymal Pressures After Basal Cisternostomy for Head Injury

BACKGROUND

Increased brain edema in head injury is due to shift of cerebrospinal fluid (CSF) from cisterns at high pressure to brain parenchyma at low pressure. By opening basal cisterns and decreasing the increased cisternal pressure, basal cisternostomy (BC) results in reversal of CSF shift from parenchyma to cisterns, leading to decreased brain edema. Though the CSF-shift edema hypothesis is based on pressure difference between cisterns and brain parenchyma, the relationship of these pressures has not been studied.

METHODS

A prospective clinical study was conducted from November 2018 to March 2020 including adult patients with head injury who were candidates for standard decompressive hemicraniectomy (DHC). All patients had neurological assessment and head computed tomography preoperatively and postoperatively. All patients underwent BC with DHC. Postoperatively, parenchymal and cisternal pressures and neurological condition were monitored hourly for 72 hours.

RESULTS

Nine (5 men, 4 women) patients with head injury (mean age, 45.7 years; range, 25-72 years) underwent DHC-BC. Median Glasgow Coma Scale score of patients at admission was 8 (range, 4-14), and median midline shift on computed tomography was 8 mm (range, 7-12 mm). There was a significant difference between opening (25.70 ± 10.48 mm Hg) and closing (11.30 ± 5.95 mm Hg) parenchymal pressures (t₉ = 3.963, P = 0.003). Immediate postoperative cisternal pressure was 1-11 mm Hg and was lower than immediate postoperative parenchymal pressure in all except 1 patient. Postoperatively, if cisternal pressure remained low, parenchymal pressure also decreased, and patients showed clinical improvement. Patients showing increased cisternal pressure showed increased parenchymal pressure and clinical worsening.

CONCLUSIONS

Our study supports the CSF-shift edema hypothesis. Following DHC-BC, cisternal pressure is lowered to near-atmospheric pressure, and its relationship to parenchymal pressure predicts the future course of patients by reversal or re-reversal of CSF shift.

Cisternostomy for Management of Intracranial Hypertension in Severe Traumatic Brain Injury; Case Report and Literature Review

Main goal in the management of patients with severe traumatic brain injury (TBI) is control of intracranial pressure (ICP). Decompressive craniectomy is an accepted technique for control of refractory intracranial hypertension in patients with severe TBI. Because of high complication rate after decompressive craniectomy, new techniques such as basal cisternostomy have developed. We herein report a case of severe TBI in a 13-year-old boy treated by cisternostomy. The patient was admitted following a motor vehicle accident. Brain CT scan showed diffuse brain edema, left frontal contusion and posterior interhemispheric subdural hematoma. The patient underwent ICP monitoring. Subsequently, with 26 mmHg mean-value of ICP, he was treated surgically by cisternostomy technique. A progressive improvement of the neurological conditions in the following hours. After 5 days the boy was discharged and in the 3-months follow-up he was completely recovered. Cisternostomy could be an appropriate alternative to decompressive craniectomy for management of intracranial hypertension in patietns with sever TBI.