This is a personal account of evolution of knowledge about the etio-pathogenesis, diagnosis and treatment of over three decades as a student and later a professional neurosurgeon. This reflects an historical perspective on the subject not withstanding the tremendous advances that have taken place in the field. It is regrettable that a successful management of hydrocephalus leave aside its cure, still eludes us.

Objective: This paper highlights the hydrocephalus research efforts undertaken at AIIMS, New Delhi, supporting progress in the field. Material: Over a period of three decades, basic research, clinical investigations, and multicentric studies were undertaken. This report will review the work mainly to emphasize the need for future generations to pursue further research. Studies that impacted hydrocephalus care (mainly in India) are described, and some of these findings may be useful in other resource-challenged situations. Results: Investigative studies on the effect of shunting on brainstem auditory evoked responses (BAER), transcranial Doppler (TCD), and CT-SPECT were published offering management options for patients. Participation in the International Infant Hydrocephalus Study (IIHS) study offered opportunities to compare our approaches and develop modifications in patient care. This effort proved shunting was equal or better for young children with congenital aqueductal stenosis. Shunt infection protocols and changes made in a systematic manner helped develop local protocols to reduce postoperative shunt infections. Conclusions: Hydrocephalus research over three decades at AIIMS, New Delhi was productive and educational, confirming that locally performed investigative work can help in decision making. Further studies and active participation in international efforts are necessary to advance the field.

Hydrocephalus is a neurological disorder with an incidence of 80–125 per 100,000 live births in the United States. The molecular pathogenesis of this multidimensional disorder is complex and has both genetic and environmental influences. This review aims to discuss the genetic and molecular alterations described in human hydrocephalus, from well-characterized, heritable forms of hydrocephalus (e.g., X-linked hydrocephalus from L1CAM variants) to those affecting cilia motility and other complex pathologies such as neural tube defects and Dandy–Walker syndrome. Ventricular zone disruption is one key pattern among congenital and acquired forms of hydrocephalus, with abnormalities in cadherins, which mediate neuroepithelium/ependymal cell junctions and contribute to the pathogenesis and severity of the disease. Given the relationship between hydrocephalus pathogenesis and neurodevelopment, future research should elucidate the genetic and molecular mechanisms that regulate ventricular zone integrity and stem cell biology.

Background: Various studies highlight the significance of alterations in cerebrospinal fluid (CSF) and cerebral blood flow (CBF) dynamics in the pathogenesis of hydrocephalus and suggest the role of mathematical modeling in studying these complex interactions. Objective: This narrative review discusses mathematical models of CSF and CBF dynamics, including Marmarou's compartmental model of CSF spaces and a model of cardiac changes in cerebral arterial blood volume. The diagnostic utility of CSF compensatory parameters is described along with current information on secondary model-based indices of cerebral hemodynamics in hydrocephalus. Conclusions: Compensatory parameters derived from the model of CSF circulation have long been used in the diagnosis and management of hydrocephalus patients. However, recent studies using mathematical models of cerebral circulation also show alterations in CBF dynamics, and model-based indices of cerebral hemodynamics, which can be calculated non-invasively using transracranial Doppler ultrasonography, can be used as a complementary source of information about the state of the cerebrospinal space.

Concepts about the production, absorption, dynamics, and physiological roles of cerebrospinal fluid (CSF) have dramatically changed over the recent decades. This article will review these new concepts and detail how they must be used for a better assessment and a better understanding of the various aspects of hydrocephalus by using neuroradiological tools.

Hydrocephalus remains one of the most commonly treated neurosurgical conditions worldwide. Caring for patients with hydrocephalus requires infrastructure and political support and initiative; these are often difficult to obtain in low- and middle-income countries (LMICs). Some innovations that have arisen in LMICs have traveled up the financial gradient to high-income countries, such as the combination of endoscopic third ventriculostomy with choroid plexus coagulation to manage hydrocephalus. The development of neuro-endoscopy has played a major role in managing hydrocephalus worldwide; however, LMICs still face specific challenges, such as limited access to shunt hardware, a disproportionately high incidence of post-infectious hydrocephalus, unique microbiological spectra, and often poor access to follow-up care and neuroimaging. This has received increased attention since the Lancet Commission on Global Surgery. The goal of improving access to quality neurosurgical care through various initiatives in LMICs will be discussed in this manuscript. The need for neurosurgeons continues to grow in LMICs, where better access to neurosurgical care, adequate neurosurgical training and political support, and patient education are needed to improve the quality of life for patients with common neurosurgical conditions. Despite these challenges, treating hydrocephalus remains a worthwhile endeavor for many patients.

Fetal ventriculomegaly is one of the most frequently diagnosed abnormalities detected prenatally. The finding of additional subtle abnormalities can facilitate accurate prognoses, which may range from normal outcomes to significant neurodevelopmental sequelae. Pathogenesis and imaging patterns of ventriculomegaly and hydrocephalus in the fetus based on the pattern-recognition approach using fetal MRI are reviewed in this paper. This radiological approach may shed light on clinical course prediction and therapeutic efficacy of hydrocephalus in the fetus.

Fetal ventriculomegaly (VM) refers to the abnormal enlargement of one or more ventricles of the brain in-utero. The enlargement may or may not be related to ventricular obstruction and increased intracranial pressure; therefore, the term “hydrocephalus” is not used. VM is diagnosed usually in the mid-trimester when the atrial diameter (AD) of the lateral ventricle is more than 10 mm on one or both sides. A thorough workup is then required to identify the cause as the etiology is diverse. Fetal magnetic resonance imaging (MRI) may yield additional information. Serial ultrasound follow-up would be required to assess its progression with advancing gestation. The prognosis and long-term outcomes greatly depend upon the etiology, the severity at diagnosis, progression, and associations. This article reviews the definitions, diagnosis, and workup of fetal VM, discusses follow-up protocols and prognosis, and examines the role of fetal therapy, including fetoscopic surgery in its prenatal management.

Background: Although there are several successful treatment options available today, the optimal management of posthemorrhagic hydrocephalus (PHH) still remains undetermined. Objective: To evaluate the efficacy and outcomes of contemporary treatment methods and to define current evidence-based management for PHH in premature infants. Material and Methods: Literature was reviewed to identify and analyze merits and demerits of the currently available temporizing measures and definitive treatment for premature low-birth weight babies with PHH. Results and Conclusions: Advances in treatment and increased experience have led to redefinition of treatment goals to optimize cognitive neurodevelopment, and quality of life in these premature infants with PHH. Current literature favors early diagnosis and intervention using temporizing measures, and prevention of future complications of PHH with a permanent CSF diversion method such as ventricular shunting or endoscopic third ventriculostomy.

Background: Post-infective hydrocephalus (PIH) arises as a complication of any CNS infection, and can be either communicating or noncommunicating. Objective: The aim of this article is to study the various causes of PIH and its pathophysiology and treatment. Material and Methods: The literature was searched for articles describing the causes of PIH. Results: Common causes of PIH are CNS tuberculosis (TB), neurocysticercosis, and perinatal or neonatal infection. TBM is most likely to result in hydrocephalus out of all these manifestations of CNS TB, and hydrocephalus is more likely to occur early in the course, typically 4–6 weeks after the onset of TBM, and is more common among children as compared to adults. A trial of medical management (antitubercular therapy, steroids, and decongestants) can be given to patients with communicating hydrocephalus. Ventriculoperitoneal shunt is the most employed method of CSF diversion in these patients. Though traditionally considered contraindicated, many recent studies have found ETV to be a reasonable option in patients with PIH. HCP in patients with neurocysticercosis can be associated with intraventricular cysts and racemose cysts in the basal subarachnoid cisterns. Surgical intervention is required either for cyst removal or CSF diversion. Endoscopic approaches can be used to remove the intraventricular cysts, which takes care of the HCP. PIH in infants can result either from antenatal infections (TORCH infections) or postnatal infections such as meningitis. Conclusions: Management of PIH can be challenging. Management has to be individualized.

Tuberculous meningitis (TBM) is associated with high mortality. A large proportion of patients with TBM, who survive, live with disabling neurological sequelae. Hydrocephalus is one of the common complications of TBM, seen in up to 80% of patients. Hydrocephalus may be a presenting feature or may develop paradoxically after the commencement of antituberculosis treatment. The Hallmark pathological feature of TBM is a thick gelatinous exudate, dominantly present at basal parts of the brain. Exudate encases and strangulates cranial nerve trunks like optic nerve, optic chiasma, and vessels of the circle of Willis. Basal exudate also blocks the cerebrospinal fluid (CSF) flow in the brain, resulting in ventriculomegaly. It is often difficult to differentiate between two common types (communicating and obstructive) of hydrocephalus on basis of routine neuroimaging. Progressive hydrocephalus, clinically manifests with a potentially life-threatening high intracranial pressure. Patients with deteriorating vision loss and deteriorating consciousness, often need a surgical CSF diversion procedure (ventriculoperitoneal shunt or endoscopic third ventriculostomy) to be performed. CSF diversion may be life-saving. However, the long-term benefits of CSF diversion are largely unknown.

Hydrocephalus is characterized by the increased volume of cerebrospinal fluid (CSF) with enlarged cerebral ventricles. In nearly 50% of the patients, if left untreated, the balance between CSF production and absorption is achieved, resulting in arrested hydrocephalus (AH). However, 15% of them who are diagnosed as arrested can progress over a period of time. Importantly, a large fraction of patients with hydrocephalus in India, may not have access to tertiary level care. Therefore, both progressive hydrocephalus and insidious progression of AH with related mortality and morbidity could be higher in India. The pathophysiology behind AH and insidious progression of AH are poorly established. Unfortunately, there are no established clinical or radiological parameters identifying or predicting AH from progressive hydrocephalous. Diagnosis is often based on a combination of neurological, psychometric, and magnetic resonance imaging (MRI) findings. Invasive monitoring of intracranial pressure (ICP) and telemetric ICP measurement is increasingly helping surgeons to detect insidious progressive AH in the early stages. In patients with AH, surgery may not be always necessary and a conservative approach is often adopted. On the contrary, AH that becomes progressive may require intervention. Surgical intervention should not be delayed and endoscopic third ventriculostomy (ETV) is preferable over shunt placement. Importantly, comprehensive counseling and the appropriate selection of patients are pivotal in improving outcomes and reducing complications.

Background: Hydrocephalus associated with posterior fossa tumor (PFT) is a common neurosurgical problem, the management of which is still controversial. Aim: To provide an overview of the advantages and limitations of different management strategies for hydrocephalus associated with PFT both before and after resection of these tumors. Methods: Structured review of the literature on the management of hydrocephalus in PFT both in children and adults. Results: The incidence of hydrocephalus associated with PFT at the time of presentation is more in children (70–90%) than adults (10–21%). This difference is maintained for hydrocephalus after the resection of PFT (~30% for children and 1.2–6.9% for adults). Preresection hydrocephalus is obstructive while emerging evidence in the literature suggests that postresection hydrocephalus may have a communicating component. The treatment of preresection hydrocephalus associated with PFT has undergone a paradigm shift in the past two decades. Preoperative Cerebrospinal Fluid (CSF) diversion is less commonly used except when required by the clinical condition of the patient. Preresection hydrocephalus may be treated by steroid use and early tumor removal, perioperative use of external ventricular drainage, or endoscopic third ventriculostomy in selected patients. Various prediction scales are available to assess the risk of postresection hydrocephalus in PFT. Certain histological tumor types and molecular phenotypes of PFT are more commonly associated with hydrocephalus. CSF diversion through endoscopic third ventriculostomy or ventriculoperitoneal shunts remains the management strategies for postresection hydrocephalus. The failure rates and the time-to-failure of both endoscopic third ventriculostomy and CSF shunts in PFT are variable and surgeons should be aware of these while taking management decisions. Conclusions: Hydrocephalus associated with PFT affects the quality of life of patients with such lesions. Routine preoperative CSF diversion is not necessary for the vast majority of patients with posterior fossa tumor-related hydrocephalus. A high index of suspicion and aggressive surveillance is required for the early identification and appropriate management of postresection hydrocephalus. Future studies are needed to address several unanswered questions pertaining to the management of this condition.

Background: Management of complex/multiloculated/septated hydrocephalus is challenging. Neuroendoscopy has been well-established when compared to multiple shunt placements in management of multiloculated hydrocephalus (MH). The main aim of neuroendoscopy is to convert multiple locules into a single locule and drain it by either third ventriculostomy or ventriculoperitoneal shunt. Objective: The objective is to reduce the number of surgical procedures and improve the quality of life. Neuroendoscopy avoids multiple shunt placement and need for revision of shunt. Methods: Literature review regarding natural history, pathogenesis, classification and management of complex/uni/multiloculated hydrocephalus was extensively done and our minimal experience with these cases has been taken into consideration. Conclusion: Neuroendoscopy when combined with frameless neuronavigation is reliable, accurate, and extremely useful in maintaining orientation and localizing the appropriate fenestration site in MH where anatomical landmarks are grossly distorted.

Background: Hydrocephalus in presence of craniosynostosis, though relatively rare, occurs in 4%–10% cases, with an increased incidence in syndromic craniosynostosis. The optimum management in these patients is unknown. Materials and Methods: A search was performed on the departmental craniofacial database to identify all patients with craniosynostosis and hydrocephalus from January 2000 to December 2020. Diagnosis was confirmed by a meticulous review of the notes and previous imaging. These patients were grouped into two groups based on the primary treatment they received: either a cerebrospinal fluid (CSF) diversion procedure or a calvarial remodeling procedure. By analyzing the outcomes for each group, we endeavor to rationalize and outline our management strategy for this complex cohort of patients. Results: Sixty-four of 989 patients were confirmed to have hydrocephalus. Of these, 55 patients underwent calvarial expansion while nine had CSF diversion as a primary procedure. Our study demonstrates that the complication rate is lower in the primary calvarial expansion group. Furthermore, the need for a CSF diversion procedure was avoided in a significant number of these patients as a direct result. Conclusion: In the vast majority of patients with craniosynostosis and hydrocephalus, calvarial expansion surgery should be the preferred primary management option.

Chari 1 malformation, a radiologic finding of caudal cerebellar tonsillar displacement, has a clinical course that can range from benign to complications involving life-threatening hydrocephalus. While the pathophysiologic processes underlying this variation in outcome remain a matter of scientific debate, the clinical realities and decision-making conundrums that these patients pose require a coherent approach to this entity. In this review, we seek to highlight the various processes underlying the development of hydrocephalus in patients with Chiari 1 malformations. Hydrocephalus may occur as a cause, consequence, or in parallel with the development of Chiari 1 malformation, and understanding the etiology of such hydrocephalus is critical to the treatment of Chiari 1 malformations with associated hydrocephalus. We further discuss the literature pertaining to the management of these patients and unify the current scientific thinking on Chiari 1 malformations with the extant data on operative management of Chiari 1 to develop a structured and pragmatic approach to the diagnosis and management of patients with Chiari 1-associated hydrocephalus.

Hydrocephalus is the most important co-morbidity in myelomeningocele from a neurosurgical perspective. Historically, 75-80% of patients with myelomeningocele have required treatment with a shunt but recent advances including intra-uterine myelomeningocele closure and ETV-CPC are reducing this burden. The expression of hydrocephalus differs between patients and across the life span. Hydrocephalus impacts the clinical expression of other important co-morbidities including the Chiari II malformation and tethered spinal cord. Shunt failure is often the key stress to prompt symptomatic worsening of these other conditions. Shunt failure may occur with minimal ventricular change on CT or MRI in Spina Bifida patients. Waiting for radiographic changes in symptomatic SB patients with shunts may result in hydrocephalus related fatalities. It is hypothesized but not proven that shunt failure may contribute to respiratory insufficiency and be a risk factor for sudden death in adult patients with spina bifida. Excellence in hydrocephalus management in MMC is essential for proper care, good outcomes, and quality of life for patients and families.

The prevalence of hydrocephalus among patients with neurofibromatosis type I (NF1) is estimated to be between 1 and 13%. Aqueductal webs, chiasmatic-hypothalamic tumors, and thalamic mass effect related to NF changes are the common causes of NF1-related hydrocephalus. Brain tumors and moyamoya syndrome may mimic the clinical presentation of hydrocephalus in children with NF1, and should be ruled out while evaluating children with headaches. Treatment of NF1-related hydrocephalus should be personally tailored, including shunts, endoscopic procedures such as septostomy and third ventriculostomy, and tumor resection or debulking. Despite these personalized treatments, many of the primary treatments (including shunts and endoscopic procedures) fail, and patients should be screened and followed accordingly. In the current manuscript, we review the causes of NF1-related hydrocephalus, as well as treatment options.

Vein of Galen malformation (VOGM) is a fistulous arteriovenous malformation presenting in the early childhood. Hydrocephalus with VOGM develops in one half of patients during the course of the disease. The concept of hydrodynamic disorders is the key to understand the development of hydrocephalus. VOGM results in venous hypertension that secondarily disturbs cerebrospinal fluid (CSF) absorption leading to hydrocephalus and occurs frequently in infants and young children. The medullary veins are thought to be the main pathway for absorption of CSF by the cerebrofugal gradient act as the driving force. In neonates, the cavernous sinus is poorly developed and brain does not use it for venous drainage along with poor jugular bulb maturation results in poor venous drainage reserve. The presence of high flow vascular malformation with poor venous drainage reserve leads to hydrodynamic disorder, poor CSF absorption, and hydrocephalus. Apart from this, hydrocephalus secondary to intraventricular hemorrhage and physical obstruction of the enlarged VOGM at the aqueduct has been proposed. The management strategy is to perform timely endovascular treatment to correct the hydrodynamic disorder and avoid ventricular shunting. Trans-arterial embolization is the effective way, as it decreases flow in the malformation, secondarily the venous hypertension, and thereby improving the clinical symptoms related to hydrodynamic disorder. Ventricular diversion procedure is indicated in symptomatic hydrocephalus after exhausting our effort to reduce hydrodynamic pressure by endovascular embolization.

Introduction: Annually, hydrocephalus affects nearly 7 children per 10,000 live births around the world. It significantly impairs the quality of life of such children and is associated with increased morbidity and mortality The high cost of treatment and post-intervention complications add to the burden of disease. Deployment of machine learning (ML) models in actual clinical settings have led to improved outcomes. Objective: The aim of this systematic review is to analyze the utility as well as acknowledge the achievements of AI/ML in HCP decision making. Methodology: PubMed and Cochrane databases were used to perform a systematic search with proper terminology to include all the relevant articles up to May 2021. Results: Fifteen studies that described the use of ML models in the diagnosis, treatment, and prognostication of pediatric hydrocephalus were identified. The median accuracy of prediction by the ML model in various tasks listed above was found to be 0.88. ML models were most commonly employed for ventricular segmentation for diagnosis of hydrocephalus. The most frequently used model was neural networks. ML models attained faster processing speeds than their manual and non-ML-based automated counterparts. Conclusion: This study attempts to evaluate the important advances and applications of ML in pediatric hydrocephalus. These methods may be better suited for clinical use than manual methods alone due to faster automated processing and near-human accuracy. Future studies should evaluate whether the use of these models is feasible in the future for patient care and management in field settings.

Introduction: Pediatric patients treated for hydrocephalus, regardless of etiology, require continuous access to care to address the long-term sequelae from the disease progression itself and from the interventions undertaken. The challenge for all pediatric neurosurgeons is providing comprehensive and coordinated care for these patients in order to achieve a smooth and seamless transition into adult health care. Methods: A review of the literature was conducted regarding the overall concept of pediatric patients with chronic conditions transitioning to adult care. We also specifically reviewed the pediatric hydrocephalus literature to investigate the barriers of transition, models of success, and specific elements required in a transition policy. Results: The review identified several barriers that hamper smooth and successful transition from pediatric to adult care within the hydrocephalus population. These included patient-related, cultural/society-related, healthcare provider-related, and healthcare system-related barriers. Six elements for successful transitions were noted: transition policy, tracking and monitoring, transition readiness, transition planning, transfer of care, and transition completion stemming from the Got Transition center. Conclusions: A successful patient transition from pediatric neurosurgical care to adult neurosurgical care is very center-specific and depends on the available resources within that center's hospital, health system, and geo-economic environment. Six recommendations are made for transition policy implementation in resource-poor environments, including beginning the process early, preferably at age 14 years.

Hydrocephalus is a common clinical problem encountered in neurosurgical practice. With greater subspecialisation, pediatric neurosurgery has emerged as a special discipline in several countries. However, in the developing world, which inhabits a large pediatric population, a limited number of neurosurgeons manage all types of hydrocephalus across all ages. There are some essential differences in pediatric and adult hydrocephalus. The spectrum of hydrocephalus of dysgenetic origin in a neonate and that of normal pressure hydrocephalus of the old age has a completely different strategy of management. Endoscopic third ventriculostomy outcomes are known to be closely associated with age at presentation and surgery. Efficacy of alternative pathways of CSF absorption also differs according to age. Managing this disease in various age groups is challenging because of these differences in etiopathology, tempo of the disease, modalities of investigations and various treatment protocols as well as prognosis.

Background: Normal-pressure hydrocephalus (NPH) presents with the triad of gait difficulty, urinary incontinence, and cognitive decline. However, the definitive diagnosis and treatment may be challenging at times due to secondary causes of NPH (sNPH) versus idiopathic NPH (iNPH), co-existing other degenerative, vascular, and metabolic causes of similar clinical presentations. Objective: The objective of this narrative review is to outline the approach to patient evaluation and decision-making in cases where there is clinical suspicion of iNPH. Methods: This review article intends to provide a practical approach to the patients with a suspected diagnosis of iNPH. Results: The cardinal clinical features with a guide from investigations like magnetic resonance imaging (MRI) brain and cerebrospinal fluid (CSF) analysis, and CSF tap assessment have been outlined. The interpretation of conflicting MRI brain findings or CSF analysis may need resolution by further tests. The decision algorithm following the examination and investigations has been included to address the dilemma in the case of a non-supportive MRI and/or CSF tap test. Conclusion: iNPH is a treatable cause of the cognitive decline and gait disorder. While neurodegenerative causes may accompany iNPH, any patient with improvement after CSF drainage deserves therapeutic intervention.

Background: The use of programmable ventriculoperitoneal shunt (P-VPS) in idiopathic normal pressure hydrocephalus (iNPH) has increased over the last two decades, however, there is no definitive evidence to favor them over non-programmable VPS (NP-VPS). Thus, there is a growing need for studies comparing these two procedures for their efficacy and safety profile in iNPH. Objective: In this study, we attempt to quantitatively summarize the findings of all the prospective and retrospective studies that have directly compared the P-VPS and NP-VPS in terms of efficacy, complications, or overall healthcare expenditure. Methods: A systematic search was performed of PubMed, the Cochrane Library databases, and Google Scholar for studies till June 2021 comparing the outcomes of P-VPS with NP-VPS. Four studies were finally included in the quantitative analysis. A trial sequential analysis was done to evaluate the need for further studies. Results: The total rates of subdural collection (odds ratio (OR) 1.03; 95% Confidence interval (CI): 0.73–1.46; P = 0.85; I² = 12%) as well as surgically evacuated subdural collection (OR 0.46; 95% CI: 0.14–1.55; P = 0.21; I² = 75%) were not significantly different for P-VPS compared to NP-VPS with pooled data. Similarly, the rate of postoperative infection was found to be similar between the two types of VPS (OR 0.98; 95% CI: 0.39–2.5; P = 0.97; I² = 0%). The trial sequential analysis (TSA) for the need of surgical evacuation of subdural collection and shunt revision revealed that the meta-analysis of the currently accrued information is not conclusive. Conclusions: Though, associated with higher initial costs, P-VPS does not seem to result in increased healthcare costs in the long run while enabling the surgeon to titrate the opening pressure and avoiding additional surgical procedures like shunt revision or evacuation of subdural collection at least theoretically. However, further trials with a greater sample size are needed to confirm these findings as the current accrued information size is insufficient to reach an unequivocal verdict.

Background: Post-traumatic hydrocephalus (PTH) is a sequel of traumatic brain injury (TBI) that is seen more often in patients undergoing decompressive craniectomy (DC). It is associated with prolonged hospital stay and unfavorable outcomes. Objective: To study the incidence and risk factors for development of PTH in patients undergoing DC in our institution and to review the literature on PTH with respect to incidence, risk factors, pathophysiology, and outcomes of management. Methods: Data from 95 patients (among 220 patients who underwent DC for TBI and fulfilled the inclusion criteria) over a 5-year period at Christian Medical College, Vellore were collected and analyzed to study the incidence and possible risk factors for development of PTH. A review of the literature on PTH was performed by searching PUBMED resources. Results: Thirty (31.6%) out of 95 patients developed post-traumatic ventriculomegaly, of whom seven (7.3%) developed symptomatic PTH, necessitating placement of ventriculoperitoneal shunt (VPS). No risk factor for development of PTH could be identified. The reported incidence of PTH in the literature is from 0.07% to 29%, with patients undergoing DC having a higher incidence. Younger age, subarachnoid hemorrhage, severity of TBI, presence of subdural hygroma, and delayed cranioplasty after DC are the main risk factors reported in the literature. Conclusions: PTH occurs in a significant proportion of patients with TBI and can lead to unfavorable outcomes. PTH has to be distinguished from asymptomatic ventriculomegaly as early as possible so that a CSF diversion procedure can be planned early during development of PTH.

Background: Hydrocephalus associated with subarachnoid hemorrhage is a common neurosurgical problem, the management of which is tailor-made to the patient. It is usually seen with an aneurysmal bleed and is independent of the primary modality of treatment. Aim: This study aimed to provide a comprehensive overview of this important association and discuss the various available treatment modalities. Materials and Methods: A detailed review of the literature was done on the risk factors, pathogenesis, and treatment of hydrocephalus in the setting of subarachnoid hemorrhage. Results: Hydrocephalus occurs in 6% to 67% of subarachnoid hemorrhage (SAH). It may present as acute, subacute, or chronic at the time of presentation. Diagnosis is made with a plain computed tomography scan of the brain, and the treatment is observant, temporary, or permanent cerebrospinal fluid diversion. Conclusion: Hydrocephalus associated with SAH interferes with the outcome of SAH. It prolongs the hospital stay, besides causing additional morbidity. The various risk factors, if present, should warn us to be vigilant, and management is definitely not uniform and is custom made to the patients' needs.

Idiopathic intracranial hypertension (IIH) is defined as a syndrome of raised intracranial pressure with normal imaging of the brain and cerebrospinal fluid (CSF) composition. There is a rising incidence and prevalence of this disease related to the increased prevalence of obesity. It typically affects women of working age, and headache is the predominant morbidity in over 90%. The disease is also more prevalent in young males. There are many controversies and myths that surround IIH. There are currently few treatment options for IIH, management is typically medical with those experiencing progressive visual loss undergoing surgical procedures. Weight loss and venous sinus stenting are a few therapies directed at the etiology.

Malignant meningitis (MM) is the diffuse involvement of the leptomeninges by infiltrating cancer cells, most frequently from lung and breast cancers. This review is aimed to discuss the current advances in the diagnosis and management of MM, along with management of MM-associated hydrocephalus. We reviewed the literature using PubMed and Google Scholar search engines, focusing on various recent randomized controlled trials and clinical trials on MM. Given the hallmark multifocal involvement, the clinical symptoms and signs are also random and asymmetric. There are three important pillars for establishing a diagnosis of MM: clinical examination, neuroimaging, and CSF cytological findings. Several factors should be considered in decision-making, including performance status, neurological findings (clinical, MRI, and CSF flow dynamic), and evaluation of the primary tumor (nature and systemic dissemination). Response Assessment in Neuro-Oncology (RANO) working group recommended the objective assessment of disease for evaluating the progression and response to therapy. Pillars of current management are mainly focal irradiation and intrathecal or systemic chemotherapy. Symptomatic hydrocephalus is managed with a ventriculoperitoneal shunt, lumboperitoneal shunt, or endoscopic third ventriculostomy as palliative procedures, providing significant improvement in performance scores in the limited survival time of patients with MM. Studies using novel therapeutic approaches, such as new biological or cytotoxic compounds, are ongoing. Despite the use of all the combinations, the overall prognosis remains grim; therefore, decision-making for treatment should predominantly be based on attaining an optimal quality of life.

Background: Spontaneous intracranial hypotension (SIH) is a highly misdiagnosed and underdiagnosed disorder. Objective: Update evaluation and treatment of spontaneous intracranial hypotension. Methods and Material: Narrative review. Results: Traditionally, SIH is diagnosed when a headache has developed spontaneously and in temporal relation to a CSF leak (evident on imaging) and/or CSF hypotension (lumbar puncture opening pressure <60 mm CSF). However, lumbar puncture is not mandatorily required to diagnose SIH. Besides headache, other symptoms such as nausea/vomiting in 50.6%, neck pain/stiffness in 33%, tinnitus in 19%, dizziness in 14%, hearing disturbances in 10.7%, followed by visual disturbances, vertigo, back pain, and cognitive symptoms may be present. In suspected cases of SIH, brain and spine should be evaluated with MRI. Dynamic computerized tomographic myelography is required to demonstrate the site of spinal CSF leak. Epidural blood patch (EBP) is a minimally invasive treatment for spontaneous intracranial hypotension (SIH) refractory to medical management and provides symptomatic relief in up to 90% of patients even in patients with bilateral subdural hematomas. The CSF-venous fistulas do not respond well to EBP, and the most definitive curative treatment is the surgical closure of the fistula. Conclusions: The SIH is a distinct entity and requires a high index of suspicion for diagnosis. A post-contrast MRI should be included for evaluation of headaches. Spinal MRI should be done to demonstrate the site of leak. Epidural blood patch therapy is the most effective treatment of SIH. Most SDHs associated with SIH do not require treatment.

Background: The treatment of hydrocephalus has evolved over centuries from being an enigma to the use of complex bioprosthetics. Major developments have taken place in the past few decades in shunt hardware and technology, with the use of complex flow regulating valves and biomaterials such as medical-grade silicone having revolutionized the management of hydrocephalus. Objective: To discuss the evolution of shunts over the decades and how they will evolve in the future. Material and Methods: In this article, we mention an overview of the evolution of shunt technology and hardware from the prehistoric, pre-shunt era to the modern shunt and a brief insight into the future of hydrocephalus treatment. We review the history, development, and pioneers in shunt development and discuss the various types and parts of a shunt system. Conclusions: Shunts have been developed from the works of Galen and Hippocrates to the latest technologies using in vivo flow biosensors, computational analysis of flow dynamics, and use of artificial intelligence. This has led to an individualized and appropriate management that can be provided to even the most complex cases of hydrocephalus.

Background: Ventriculoperitoneal shunt surgery (VPS) is a simple solution to the problem of hydrocephalus. However, it is associated with significant complications. Meticulous attention to a variety of factors, techniques, and nuances in VPS can reduce these complications. Objective: To review the various techniques and nuances during the different stages of VPS. Methods and Material: PubMed search for original and review articles dealing with various techniques used during VPS. Results: Thorough preoperative planning for VPS reduces operative time and complications. A standardized shunt surgery protocol significantly reduces shunt infection. Good and appropriate surgical technique can enhance the safety of the procedure. Anterior entry point is better than posterior entry point. Shunt tip should be away from choroid plexus, but the exact location is not vital for shunt survival. Proper placement of the shunt in the subgaleal and subcutaneous plane reduces wound and skin breakdown over the shunt. The trocar and laparoscopic methods to access the peritoneum are associated with fewer distal obstructions compared to mini-laparotomy. Perioperative antibiotic prophylaxis, use of antibiotic-impregnated shunts, and sutures are proven techniques to reduce shunt infection. Conclusions: Preoperative planning, a standardized shunt surgery protocol, good surgical technique, gentle tissue handling, and short surgery duration are essential to reduce VPS complications. Specifically, use of anterior entry point, correct tunneling of the shunt in the subgaleal and subcutaneous plane, appropriate antibiotic prophylaxis, use of antibiotic-impregnated shunts, and meticulous skin closure using antimicrobial sutures can lead to a reduction in shunt malfunction and infection.

Introduction: Alternate approaches such as ventriculoatrial (VA) or ventriculopleural (VPL) procedures still have a place in the surgical armamentarium for patients with recurrent ventriculoperitoneal (VP) shunt failures related to defective absorption, infections, or frequent malfunctions. Methods: We reviewed the literature and our experience with these techniques, and offered suggestions for safely performing these operations. Historical perspectives were also included to facilitate an improved understanding of the technical developments. Results: Our findings and the available medical literature suggest VA and VPL options are safe and effective alternatives for managing the complex patient with hydrocephalus. Potential issues and complications were discussed along the technical advances for a safer operation. Conclusion: The VA and VPL options should be considered for patients with recurrent VP shunt issues. They are safe and effective options for managing complex hydrocephalus patients.

Background: Lumboperitoneal shunt is a known procedure for communicating hydrocephalus. Being an extracranial procedure, it can also be utilized in normal-sized ventricles. Objective: To report our experience of lumboperitoneal shunt done with a minimal follow-up of 12 months with an emphasis on patient selection, technique, and complication avoidance. Methods: This was a retrospective analysis of patients who underwent LP shunt during October 2014–October 2019 at the authors' institute. Inclusion criteria were patients with communicating hydrocephalus due to tubercular meningitis, normal pressure hydrocephalus, idiopathic intracranial hypertension, and postoperative refractory cerebrospinal fluid leaks. Data were collected for demographics, Glasgow coma scale and Glasgow outcome scale, vision, gait, memory, urinary incontinence, failed attempts, and complications. Results: A total of 426 patients underwent the LP shunt procedure. The commonest indication was tubercular meningitis followed by idiopathic intracranial hypertension and normal pressure hydrocephalus. Age ranged from 16 to 72 years. There were 255 male and 171 female patients. The mean follow-up was 41 ± 8 months. Overall, 301 patients (70.6%) had neurological improvement. Shunt-related complications occurred in 112 (26.29%) patients, of which shunt block was the commonest. Other complications were infection in 17 (3.9%) patients and extrusion in four (0.9%) patients. Transient postural headache was seen in 46 (10.7%) patients, which gradually improved. Conclusion: Lumboperitoneal shunt was found to be a safe and effective treatment in appropriately selected communicating hydrocephalus patients. A meticulous technique reduces the complication rate.

The two shunts that are performed much less and are included here for completeness are the ventriculosubgaleal shunt and the ventriculocholecystal shunt. The ventriculosubgaleal shunt is an established treatment of hydrocephalus following germinal matrix hemorrhage in low-birth-weight neonates. It is also used in the treatment of post-infective hydrocephalus in children. In our institution protocol, we have used this shunt in a wide variety of indications, especially in children below six months of age. Ventriculocholecystal shunts are very much a salvage shunts when all else fails.

Background and Objective: To analyze the common problems in shunt surgery and measures to avoid them. Management of hydrocephalus takes up as much as 50% of a pediatric ' 'neurosurgeon's time, and these are notoriously prone to complications. In this article, the author analysis his series of ventriculoperitoneal shunts and discusses his technique, nuances and avoidance of shunt complications. Methods and Materials: The author will review common issues related to hydrocephalus shunt management with a review of 549 procedures and associated complications. Results: Key features and basic principles of complication avoidance in shunt surgery is provided. The analysis looks into the complications and ways to avoid them based on the author's experience Conclusions: Specific measures may be adopted to minimize or avoid these complications. These will be discussed based on the author's series and experiences.

Background: Endoscopic third ventriculostomy (ETV) has become a proven modality for treating obstructive and selected cases of communicating hydrocephalus. Objective: This review aims to summarize the indications, preoperative workup, surgical technique, results, postoperative care, complications, advantages, and limitations of an ETV. Materials and Methods: A thorough review of PubMed and Google Scholar was performed. This review is based on the relevant articles and authors' experience. Results: ETV is indicated in obstructive hydrocephalus and selected cases of communicating hydrocephalus. Studying preoperative imaging is critical, and a detailed assessment of interthalamic adhesions, the thickness of floor, arteries or membranes below the third ventricle floor, and prepontine cistern width is essential. Blunt perforation in a thin floor, while bipolar cautery at low settings and water jet dissection are preferred in a thick floor. The appearance of stoma pulsations and intraoperative ventriculostomography reassure stoma and basal cistern patency. The intraoperative decision for shunt, external ventricular drainage, or Ommaya reservoir can be taken. Magnetic resonance ventriculography and cine phase-contrast magnetic resonance imaging can determine stoma patency. Good postoperative care with repeated cerebrospinal fluid drainage enhances outcomes in selected cases. Though the complications mostly occur in an early postoperative phase, delayed lethal ones may happen. Watching live surgeries, assisting expert surgeons, and practicing on cadavers and models can shorten the learning curve. Conclusion: ETV is an excellent technique for managing obstructive and selected cases of communicating hydrocephalus. Good case selection, methodical technique, and proper training under experts are vital.

Background: The global burden of pediatric hydrocephalus is high, causing significant morbidity and mortality among children especially in low- and middle-income countries. It is commonly treated with ventriculoperitoneal shunting, but in recent years, the combined use of endoscopic third ventriculostomy (ETV) and choroid plexus coagulation (CPC) has enabled patients to live without a shunt. Objective: We aim to give an overview of ETV+CPC for the treatment of hydrocephalus in infants, focusing on patient selection, perioperative care, and long-term follow-up. Methods and Material: We summarize observational studies and randomized trials on the efficacy and safety ETV+CPC, mainly from Uganda and North America. The equipment needs and operative steps of ETV+CPC are enumerated. At the end of the article, three illustrative cases of infants who underwent ETV+CPC with differing outcomes are presented. Results: The likelihood of success following ETV+CPC is the highest among infants older than 1 month, those with noninfectious hydrocephalus (e.g., aqueductal stenosis and myelomeningocele), and those previously without a shunt. Poor outcomes are seen in patients with posthemorrhagic hydrocephalus or evidence of cisternal scarring. Failure of ETV+CPC most commonly occurs within 3–6 months of surgery. Conclusions: ETV+CPC is an effective and safe alternative to ventriculoperitoneal shunting in appropriately selected infants with hydrocephalus. Long-term studies on functional and neurocognitive outcomes following ETV+CPC will help guide clinicians in decision making, allowing as many children as possible to attain shunt freedom.

Background: Hydrocephalus is an abnormal excessive accumulation of cerebrospinal fluid (CSF) in the cavity and spaces of the brain. Endoscopic third ventriculostomy (ETV) has been an established treatment modality for congenital hydrocephalus. However, in very young infants, the results are challenging. In our study, we have evaluated whether ETV really offers an acceptable complication-free postoperative course. Objective: To study the complication and mortality rate in infants having congenital hydrocephalus treated with ETV. Materials and Methods: This is a single-center prospective study conducted at the Department of Neurosurgery, K. G. M. U, Lucknow, from January 2019 to February 2020. We studied 40 infants presenting with clinical and radiological features suggestive of congenital hydrocephalus. Follow-up was done at the first, third, and sixth months after discharge. Results: Nineteen infants (47.5%) required a second CSF diversion procedure at 6 months of follow-up. The failure rate was significantly higher in infants less than 3 months of age (P value of 0.04). The ETV site bulge was the most frequent complication encountered in the postoperative period, occurring in 20% of the cases. Eventually, all these infants required a ventriculoperitoneal shunt; 15% developed clinical features consistent with the diagnosis of post-ETV meningitis. The ETV site CSF leak occurred in 10% of the patients. Subdural hygroma developed in 7.5% of the patients; 17.5% of the patients contributed to mortality with a mean time of expiry of 22 days post-procedure. All these deaths had multifactorial causes and could not be said as a complication or failure of ETV. Conclusion: We do not recommend ETV for infants less than 3 months because of a high failure rate. The ETV site bulge was the most reliable and earliest marker of failure and a second CSF diversion surgery should be immediately considered.

Background: Shunt infection is the most significant morbidity associated with shunt surgery. Based on the existing literature for the prevention and management of shunt infection, region and resource-specific recommendations are needed. Methods: In February 2020, a Guidelines Development Group (GDG) was created by the Indian Society of Paediatric Neurosurgery (IndSPN) to formulate guidelines on shunt infections, which would be relevant to our country and LMIC in general. An initial email survey identified existing practices among the membership of the IndSPN, and eight broad issues pertaining to shunt infection were identified. Next, members of the GDG performed a systematic review of the literature on the prevention and management of shunt infection. Then, through a series of virtual meetings of the GDG over 1 year, evidence from the literature was presented to all the members and consensus was built on different aspects of shunt infection. Finally, the guidelines document was drafted and circulated among the GDG for final approval. Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to grade the evidence and strength of recommendation. Results: The guidelines are divided into eight sections. Level I and Level II evidence was available for only five recommendations and led to a moderate level of recommendations. Most of the available evidence was at Level III and below, and hence the level of recommendation was low or very low. A consensus method was used to provide recommendations for several issues. Conclusions: Although most of the recommendations for the prevention and management of shunt infections are based on a low level of evidence, we believe that this document will provide a useful reference to neurosurgeons not only in India but also in other low and middle income countries. These guidelines need to be updated as and when new evidence emerges.

Background: Endoscopic Third Ventriculostomy (ETV) is increasingly being accepted as the treatment of choice in place of Ventriculo-Peritoneal (VP) Shunt for hydrocephalus. However, their differences in cognitive and Quality of Life (QOL) scores have not been studied much in children. Objective: To compare the outcome, cognitive function, and QOL between ETV and VP shunt. Methods: Patients of non-tumor hydrocephalus treated with ETV or/and VP shunt underwent cognitive assessment (using modified child MMSE standardized as per the age group) and QOL (using PedsQL as per the age group in Physical, Emotional, Social, and School Functioning domains) in addition to the outcome of not requiring additional intervention. Results: Out of 139 patients, there were 29 infants and 40 children upto 14 years. Among these children, ETV was the primary intervention in 45, VP shunt in 24, and could be studied for a mean follow-up of 1.7 years. Though ETV required lesser additional intervention than VP shunt (19.2% vs. 28.6%) in toddlers and older children, there was no overall significant difference. Subnormal cognitive scores were noted in 25%, 40%, and 50% after ETV, single shunt procedure, and multiple shunt procedures, respectively, with no statistically significant difference. Among the different domains of QOL, the child reported scores in the social domain were significantly better after ETV than VP shunt (475[+13] vs. 387[+43], P value 0.03), whereas most other scores were non-significantly better following ETV. Conclusion: Patients who underwent ETV show a trend for better clinical outcome, cognitive function, and QOL with significantly better child-reported QOL scores in the social domain.

Background: The natural history and treatment outcomes in adult patients with hydrocephalus is a broad and heterogeneous topic that encompasses the natural history of the various subtypes of adult hydrocephalus with or without treatment; their surgical operative results, including symptom improvements, treatment failure, short- and long-term complications, and reoperations; and morbidity, mortality, and patient-centered health-related quality of life (HRQoL). Objective, Methods, and Materials: The objective of this review is to present a current update on the natural history and treatment outcomes, including QoL, for adults with hydrocephalus with a focus on patients with idiopathic normal pressure hydrocephalus (iNPH). A nonsystematic review of relevant literature was summarized. Results and Conclusions: The natural history for untreated patients with iNPH is poor, with both increased mortality and morbidity. It is strongly recommended that practitioners follow established guidelines to select patients with suspected iNPH while using objective measures of gait, balance, and cognition for consideration of treatment with a CSF shunt. Other factors such as patient-related medical comorbidities or frailty may need to be factored into the decision-making process before surgical treatment is offered. As a rule, failure to select patients based on the identified guidelines will result in a significantly lower positive response to treatment with a CSF shunt. Over 90% of iNPH patients who undergo CSF-shunt treatment demonstrate symptomatic relief after surgery, and long-term studies have shown that in most patients, the clinical improvements are long-lasting, with over 70% demonstrating improvement longer than 6 years after treatment. There is no evidence to support the routine use of endoscopic third ventriculostomy (ETV) to treat patients with iNPH. There is limited data regarding HRQoL in patients with iNPH. In addition to objective measures of outcomes focused on gait and cognition, it is equally important for future studies to assess patient-centered subjective measures of HRQoL.

Background: This review documents the evolution of the Vellore grading system for tuberculous meningitis and hydrocephalus (TBMH), its evaluation by different authors, and analyzes the need for further modification in light of the published literature. Methods: Published literature was searched in PubMed and Google Scholar using the search terms, “tuberculous meningitis hydrocephalus” and “Vellore grading.” The retrieved articles were reviewed by the author and the appropriate ones were chosen for inclusion in the study. Results: Vellore grade (1–4, with 1 being the best grade and 4 being the worst grade) was found to be the sole statistically significant factor associated with outcome following VP shunt or ETV in several studies. Additionally, Vellore grades also correlate with the likelihood of success following ETV. However, the use of response to external ventricular drainage (EVD) in managing Vellore grade 4 patients has remained contentious as a small but significant proportion of patients have a good outcome following shunt, irrespective of their response to the EVD. The latter findings suggest that grade 4 patients might not constitute a homogenous group. It is proposed that grade 4 be subdivided into grades 4a and 4b, which might help in prognostication and in surgical management of the hydrocephalus in patients with TBMH. Conclusions: Vellore grading has proved its utility as a prognostic tool and can aid surgical decision-making. However, management of patients in grade 4 might be better rationalized with its division into grades 4a and 4b.

Background: Hydrocephalus is a complex issue characterized by increased intracranial pressure secondary to obstruction of cerebrospinal fluid flow and occasionally due to overproduction. As a result, the entity has challenges of different dimensions at the level of understanding and management. Methods: A literature search, systematic review, and meta-analysis of eligible studies were conducted in the major databases. The literature review included relevant articles on hydrocephalus published until June 1, 2021 (no starting date), databases being the only limitation considering the broadness of the subthemes. Controversies themes were chosen among the literature, not including treatment dilemmas and hydrocephalus research. The further detailed search included these selected themes and an updated literature review on the subjects. Results and Discussion: Controversies are a hallmark of incomplete science; most complex concepts harbor several debates at various levels. This article reviews controversies in hydrocephalus, offering some updates on popular discussions. It is not meant to be an exposition of the topics themselves but to collect the status quo of unresolved concepts in hydrocephalus. Conclusions: As with most chronic and complex disorders, hydrocephalus welcomes controversy as a healthy discussion platform to exist until we understand the disorder to its minutest.