A set of related medical disorders that lack a proper classification system and diagnostic criteria is like a society without laws. The result is incoherence at best, chaos at worst. For this reason, the International Classification of Headache Disorders (ICHD) is arguably the single most important breakthrough in headache medicine over the last 50 years. The ICHD identifies and categorizes more than a hundred different kinds of headache in a logical, hierarchal system. Even more important, it has provided explicit diagnostic criteria for all of the headache disorders listed. The ICHD quickly became universally accepted, and criticism of the classification has been minor relative to that directed at other disease classification systems. Over the 20 years following publication of the first edition of the ICHD, headache research has rapidly accelerated despite sparse allocation of resources to that effort. In summary, the ICHD has attained widespread acceptance at the international level and has substantially facilitated both clinical research and clinical care in the field of headache medicine.

International Classification of Headache Disorders

Endoscopic third ventriculostomy (ETV) is considered as a treatment of choice for obstructive hydrocephalus. It is indicated in hydrocephalus secondary to congenital aqueductal stenosis, posterior third ventricle tumor, cerebellar infarct, Dandy-Walker malformation, vein of Galen aneurism, syringomyelia with or without Chiari malformation type I, intraventricular hematoma, post infective, normal pressure hydrocephalus, myelomeningocele, multiloculated hydrocephalus, encephalocele, posterior fossa tumor and craniosynostosis. It is also indicated in block shunt or slit ventricle syndrome. Proper Pre-operative imaging for detailed assessment of the posterior communicating arteries distance from mid line, presence or absence of Liliequist membrane or other membranes, located in the prepontine cistern is useful. Measurement of lumbar elastance and resistance can predict patency of cranial subarachnoid space and complex hydrocephalus, which decides an ultimate outcome. Water jet dissection is an effective technique of ETV in thick floor. Ultrasonic contact probe can be useful in selected patients. Intra-operative ventriculo-stomography could help in confirming the adequacy of endoscopic procedure, thereby facilitating the need for shunt. Intraoperative observations of the patent aqueduct and prepontine cistern scarring are predictors of the risk of ETV failure. Such patients may be considered for shunt surgery. Magnetic resonance ventriculography and cine phase contrast magnetic resonance imaging are effective in assessing subarachnoid space and stoma patency after ETV. Proper case selection, post-operative care including monitoring of ICP and need for external ventricular drain, repeated lumbar puncture and CSF drainage, Ommaya reservoir in selected patients could help to increase success rate and reduce complications. Most of the complications develop in an early post-operative, but fatal complications can develop late which indicate an importance of long term follow up.

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Endoscopic third ventriculostomy.

Study Design  Literature review. Objective  Atlantoaxial dislocation (AAD) is a rare and potentially fatal disturbance to the normal occipital-cervical anatomy that affects some populations disproportionately, which may cause permanent neurologic deficits or sagittal deformity if not treated in a timely and appropriate manner. Currently, there is a lack of consensus among surgeons on the best approach to diagnose, characterize, and treat this condition. The objective of this review is to provide a comprehensive review of the literature to identify timely and effective diagnostic techniques and treatment modalities of AAD. Methods  This review examined all articles published concerning “atlantoaxial dislocation” or “atlantoaxial subluxation” on the PubMed database. We included 112 articles published between 1966 and 2014. Results  Results of these studies are summarized primarily as defining AAD, the normal anatomy, etiology of dislocation, clinical presentation, diagnostic techniques, classification, and recommendations for timely treatment modalities. Conclusions  The Wang Classification System provides a practical means to diagnose and treat AAD. However, future research is required to identify the most salient intervention component or combination of components that lead to the best outcomes.

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A Review of the Diagnosis and Treatment of Atlantoaxial Dislocations

The cerebrospinal fluid (CSF) space consists of the intracerebral ventricles, subarachnoid spaces of the spine and brain (e.g., cisterns and sulci), and the central spinal cord canal. The CSF protects the central nervous system (CNS) in different ways involving metabolic homeostasis, supply of nutrients, functioning as lymphatic system, and regulation of intracranial pressure. CSF is produced by the choroid plexus, brain interstitium, and meninges, and it circulates in a craniocaudal direction from ventricles to spinal subarachnoid space from where it is removed via craniocaudal lymphatic routes and the venous system. The CSF is renewed 3-5 times daily and its molecular constituents are mainly blood-derived (80%), while the remainder consists of brain-derived and intrathecally produced molecules (20%). The CSF space is separated from the vascular system by the blood-CSF barrier (BCB), whereas the blood-brain barrier (BBB), responsible for maintaining the homeostasis of the brain, is located between brain parenchyma and vascular system. Although both barriers have similar functions, they differ with regard to their morphologic and functional properties. Both barrier systems are permeable not only for small molecules, but also for macromolecules and circulating cells. The transport of molecules across the BBB and BCB is regulated by passive diffusion (e.g., albumin, immunoglobulins) and facilitated or active transport (e.g., glucose). The extracellular space volume, potassium buffering, CSF circulation, and interstitial fluid absorption are mainly regulated by aquaporin-4 channels, which are abundantly located at the blood-brain and brain-CSF interfaces. The composition of CSF shows a high dynamic range, and the levels of distinct proteins vary due to several influencing factors, such as site of production (brain or blood-derived), site of sampling (ventricular or lumbar), CSF flow rate (BCB function), diurnal fluctuations of CSF production rate, and finally, molecular size of blood-derived proteins (IgM vs. albumin) and circadian rhythm (glucose, prostaglandin D synthase). Alterations of lumbar CSF are mainly influenced by processes of the CNS located adjacent to the ventricular and spinal CSF space and less by pathologies in cortical areas remote from the ventricles.

The cerebrospinal fluid and barriers – anatomic and physiologic considerations

Importance Chronic subdural hematoma (CSDH) is a trauma-associated condition commonly found in elderly patients. Surgery is currently the treatment of choice, but it carries a significant risk of recurrence and death. Nonsurgical treatments remain limited and ineffective. Our recent studies suggest that atorvastatin reduces hematomas and improves the clinical outcomes of patients with CSDH. Objective To investigate the safety and therapeutic efficacy of atorvastatin to nonsurgically treat patients with CSDH. Design, Setting, and Participants The Effect of Atorvastatin on Chronic Subdural Hematoma (ATOCH) randomized, placebo-controlled, double-blind phase II clinical trial was conducted in multiple centers in China from February 2014 to November 2015. For this trial, we approached 254 patients with CSDH who received a diagnosis via a computed tomography scan; of these, 200 (78.7%) were enrolled because 23 patients (9.1%) refused to participate and 31 (12.2%) were disqualified. Interventions Patients were randomly assigned to receive either 20 mg of atorvastatin or placebo daily for 8 weeks and were followed up for an additional 16 weeks. Main Outcomes and Measures The primary outcome was change in hematoma volume (HV) by computed tomography after 8 weeks of treatment. The secondary outcomes included HV measured at the 4th, 12th, and 24th weeks and neurological function that was evaluated using the Markwalder grading scale/Glasgow Coma Scale and the Barthel Index at the 8th week. Results One hundred ninety-six patients received treatment (169 men [86.2%]; median [SD] age, 63.6 [14.2] years). The baseline HV and clinical presentations were similar between patients who were taking atorvastatin (98 [50%]) and the placebo (98 [50%]). After 8 weeks, the HV reduction in patients who were taking atorvastatin was 12.55 mL more than those taking the placebo (95% CI, 0.9-23.9 mL; P  = .003). Forty-five patients (45.9%) who were taking atorvastatin significantly improved their neurological function, but only 28 (28.6%) who were taking the placebo did, resulting in an adjusted odds ratio of 1.957 for clinical improvements (95% CI, 1.07-3.58; P  = .03). Eleven patients (11.2%) who were taking atorvastatin and 23 (23.5%) who were taking the placebo underwent surgery during the trial for an enlarging hematoma and/or a deteriorating clinical condition (hazard ratio, 0.47; 95% CI, 0.24-0.92; P  = .03). No significant adverse events were reported. Conclusions and Relevance Atorvastatin may be a safe and efficacious nonsurgical alternative for treating patients with CSDH. Trial Registration ClinicalTrials.gov Identifier:NCT02024373

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Safety and Efficacy of Atorvastatin for Chronic Subdural Hematoma in Chinese Patients: A Randomized ClinicalTrial

Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions. There is lack of uniformity in the treatment of CSDH amongst surgeons in terms of various treatment strategies. Clinical presentation may vary from no symptoms to unconsciousness. CSDH is usually diagnosed by contrast-enhanced computed tomography scan. Magnetic resonance imaging (MRI) scan is more sensitive in the diagnosis of bilateral isodense CSDH, multiple loculations, intrahematoma membranes, fresh bleeding, hemolysis, and the size of capsule. Contrast-enhanced CT or MRI could detect associated primary or metastatic dural diseases. Although definite history of trauma could be obtained in a majority of cases, some cases may be secondary to coagulation defect, intracranial hypotension, use of anticoagulants and antiplatelet drugs, etc., Recurrent bleeding, increased exudates from outer membrane, and cerebrospinal fluid entrapment have been implicated in the enlargement of CSDH. Burr-hole evacuation is the treatment of choice for an uncomplicated CSDH. Most of the recent trials favor the use of drain to reduce recurrence rate. Craniotomy and twist drill craniostomy also play a role in the management. Dural biopsy should be taken, especially in recurrence and thick outer membrane. Nonsurgical management is reserved for asymptomatic or high operative risk patients. The steroids and angiotensin converting enzyme inhibitors may also play a role in the management. Single management strategy is not appropriate for all the cases of CSDH. Better understanding of the nature of the pathology, rational selection of an ideal treatment strategy for an individual patient, and identification of the merits and limitations of different surgical techniques could help in improving the prognosis.

Chronic subdural hematoma.

Cerebrospinal fluid (CSF) rhinorrhea occurs due to communication between the intracranial subarachnoid space and the sinonasal mucosa. It could be due to trauma, raised intracranial pressure (ICP), tumors, erosive diseases, and congenital skull defects. Some leaks could be spontaneous without any specific etiology. The potential leak sites include the cribriform plate, ethmoid, sphenoid, and frontal sinus. Glucose estimation, although non-specific, is the most popular and readily available method of diagnosis. Glucose concentration of > 30 mg/dl without any blood contamination strongly suggests presence and the absence of glucose rules out CSF in the fluid. Beta-2 transferrin test confirms the diagnosis. High-resolution computed tomography and magnetic resonance cisternography are complementary to each other and are the investigation of choice. Surgical intervention is indicated, when conservative management fails to prevent risk of meningitis. Endoscopic closure has revolutionized the management of CSF rhinorrhea due to its less morbidity and better closure rate. It is usually best suited for small defects in cribriform plate, sphenoid, and ethmoid sinus. Large defects can be repaired when sufficient experience is acquired. Most frontal sinus leaks, although difficult, can be successfully closed by modified Lothrop procedure. Factors associated with increased recurrences are middle age, obese female, raised ICP, diabetes mellitus, lateral sphenoid leaks, superior and lateral extension in frontal sinus, multiple leaks, and extensive skull base defects. Appropriate treatment for raised ICP, in addition to proper repair, should be done to prevent recurrence. Long follow-up is required before leveling successful repair as recurrences may occur very late.

Endoscopic management of cerebrospinal fluid rhinorrhea.

A lumbar peritoneal (LP) shunt is a technique of cerebrospinal fluid (CSF) diversion from the lumbar thecal sac to the peritoneal cavity. It is indicated under a large number of conditions such as communicating hydrocephalus, idiopathic intracranial hypertension, normal pressure hydrocephalus, spinal and cranial CSF leaks, pseudomeningoceles, slit ventricle syndrome, growing skull fractures which are difficult to treat by conventional methods (when dural defect extends deep in the cranial base or across venous sinuses and in recurrent cases after conventional surgery), raised intracranial pressure following chronic meningitis, persistent bulging of craniotomy site after operations for intracranial tumors or head trauma, syringomyelia and failed endoscopic third ventriculostomy with a patent stoma. In spite of the large number of indications of this shunt and being reasonably good, safe, and effective, very few reports about the LP shunt exist in the literature. This procedure did not get its due importance due to some initial negative reports. This review article is based on search on Google and PubMed. This article is aimed to review indications, complications, results, and comparison of the LP shunt with the commonly practiced ventriculoperitoneal (VP) shunt. Shunt blocks, infections, CSF leaks, overdrainage and acquired Chiari malformation (ACM) are some of the complications of the LP shunt. Early diagnosis of overdrainage complications and ACM as well as timely appropriate treatment especially by programmable shunts could decrease morbidity. Majority of recent reports suggest that a LP shunt is a better alternative to the VP shunt in communicating hydrocephalus. It has an advantage over the VP shunt of being completely extracranial and can be used under conditions other than hydrocephalus when the ventricles are normal sized or chinked. More publications are required to establish its usefulness in the treatment of wide variety of indications.

Lumbar peritoneal shunt

Microneurosurgical operations differ from other surgery. Longer operative time, narrow and deep-seated operative corridors, hand-eye coordination, fine manipulation, and physiologic tremor present special problems. Proper understanding of visual feedback, control of physiologic tremor, better instrument design, and development of surgical skills with better precision is important for optimal surgical results. Using the pen-type precision grip with well-supported arm, wrist, hand, and fingers avoids fatigue and improves precision. Proper instrument design, patient positioning, hemostasis techniques, tilting operative table, good operative microscope, an adjustable chair, careful use of suction tube, bipolar forceps, and brain retraction play important roles in microneurosurgery. Sufficient clinical case volume or opportunity during routine operative hours may not be available in the beginning for young neurosurgeons; microsurgical training using various models can enable them to gain experience. Training models using deep-seated and narrow operative corridors, drilling, knot-tying technique, and anastomosis using fine sutures under high magnification can be practiced for skill improvement. Training laboratory and simulation modules can be useful for resident training and skill acquisition. Indigenously made inexpensive models and comparatively less expensive microscopes can be used in resource-constrained situations. The maintenance of microsurgical ability should be preserved by staying active in operative practice. The knowledge of ergonomics, proper training, observing hand movements of skillful surgeons, and the use of operative videos can improve skill. Endoscopic assistance, computer-assisted robot hand technique, and microtechnology can provide access to the smallest areas of the body.

Vijay Parihar

Papers

Chronic subdural hematoma.

Endoscopic third ventriculostomy.

Endoscopic management of cerebrospinal fluid rhinorrhea.

Lumbar peritoneal shunt

Microneurosurgical Skills Training