Idiopathic normal pressure hydrocephalus: Validation of the DESH score as a prognostic tool for shunt surgery response.

OBJECTIVE: Several radiological markers have been linked to clinical improvement after shunt surgery for idiopathic normal pressure hydrocephalus (iNPH). However, iNPH has no pathognomonic feature, and patients are still diagnosed as probable, possible, or unlikely cases based on clinical symptoms, imaging findings, and invasive supplementary tests. The predictive value of the disproportionately enlarged subarachnoid space hydrocephalus (DESH) score is not yet conclusively determined, but it might offer a more accurate diagnostic method. The aim of the present retrospective cohort study was to validate the predictive power of the DESH score for clinical improvement after shunt surgery in iNPH patients. METHODS: We retrospectively obtained presurgical MRI and/or CT scans from 71 patients with iNPH who underwent ventriculoperitoneal shunt surgery. Radiological images were evaluated for Evans index (EI), corpus callosal angle (CA), tight high convexity (THC), Sylvian fissure dilation, and focal sulci dilation. These markers were aggregated to determine the DESH score. Patient journal entries were used to subjectively determine the extent of improvement in gait function, urinary incontinence, and/or cognition as a measure of shunt surgery response. RESULTS: Multiple logistic regression analysis, controlling for age and sex (α = 0.05), showed that DESH score was significantly correlated (OR 1.77) with subjective shunt-surgery response at a minimum of 1-month follow-up. Patients with higher DESH scores were more likely to have a favorable response to shunt surgery. CONCLUSION: Aggregating radiological markers into the DESH score is useful for predicting shunt responders among iNPH patients and can aid the selection of patients for surgery. These findings provide further support for the DESH score as a diagnostic tool for iNPH.

A case-based review on the neuroendoscopic management of intraventricular and subarachnoid basal neurocysticercosis.

OBJECTIVE: Extraparenchymal localization of neurocysticercosis (NCC) is rare in non-endemic areas. A case of mixed (intraventricular, IV, and subarachnoid basal, SAB) NCC was surgically treated using the neuroendoscope and a systematic review of the literature was performed with the aim to analyze the use of this instrument in the management of the extraparenchymal forms of the parasitic disease. MATERIALS AND METHODS: Medline and Embase databases were searched for studies where the neuroendoscope was used for the management of IV/SAB NCC cysts, either for the cerebrospinal fluid diversion or cyst removal. Cyst location, complete removal, cyst breakage during removal, intraoperative and postoperative complications, administration of antihelmintic therapy, outcome and follow-up period were extracted from the articles. RESULTS: 281 patients were treated by means of the neuroendoscope. 254 patients who were described in retrospective cohort studies, came all from endemic areas, with no significant difference between sexes. Mean age at surgery was 30.7 years. Of all cysts reported in retrospective studies, 37.9% were located in the fourth ventricle. An attempt of cyst removal was described in the 84.6% of cases and an endoscopic third ventriculostomy was performed in another 76.4%. A small number of complications were reported intraoperatively (9.1%) obtaining, but a good recovery was achieved at follow-up. Only 17 ventriculoperitoneal shunts were placed after the first procedure, defining a low risk of postoperative hydrocephalus even in case of partial cyst removal. CONCLUSION: Neuroendoscopic removal of an extraparenchymal NCC cyst is a safe procedure that should be preferred for lateral and third ventricle localization and, in a specialized centre, even for a localization in the fourth ventricle if feasible. It is also efficient because of the possibility of performing an internal CSF diversion concomitantly to cyst removal, avoiding the complication registered with VPS. The need for cysticidal treatment after surgery should be addressed in a prospective study.

Syringo-Subarachnoid Shunt with Tube Versus T-Tube via the Dorsal Root Entry Zone Approach for Eccentric Syringomyelia.

OBJECTIVE: This study compared the clinical therapeutic efficacy of syringo-subarachnoid shunt placement with direct tube and T-tube via the dorsal root entry zone (DREZ) approach for treatment of eccentric syringomyelia. METHODS: A retrospective study was performed of 41 patients with idiopathic or secondary eccentric syringomyelia from November 2011 to December 2022. Syringo-subarachnoid shunt placement with direct tube or T-tube via the DREZ approach was performed. The modified Japanese Orthopaedic Association low back pain scale was used to investigate the severity of clinical symptoms. Magnetic resonance imaging was used to investigate therapeutic efficacy（reduction of the cavity volume by >10% was considered an improvement and 50% was considered a significant improvement). RESULTS: Incision length of the spinal cortex in the direct tube group was shorter than in the T-tube group (3.10 ± 0.28 cm vs. 5.03 ± 0.19 cm), with a significant difference between the 2 groups (t = -52.56, P < 0.001). Modified Japanese Orthopaedic Association score 3 months postoperatively was significantly better than the preoperative score in both the direct tube group（t = 40.954, P < 0.001） and the T-tube group（t = 24.769, P < 0.001）. Statistical comparison revealed there was no difference in imaging improvement between the direct tube group and T-tube group 3 months (χ2 = 0.20, P = 0.655) and 12 months (χ2 = 0.21, P = 0.647) postoperatively. CONCLUSIONS: Syringo-subarachnoid shunt placement with direct tube via the DREZ approach for treatment of eccentric syringomyelia is safer than with T-tube via the DREZ approach due to smaller incision length and less of a space-occupying effect with same therapeutic efficacy.

Spinal extradural arachnoid cysts: a rare entity and review of the literature.

OBJECTIVE: Spinal extradural arachnoid cysts (SEDC) are rare primary spinal lesions, accounting for less than 1% of all spinal epidural lesions. The literature contains only case reports of this pathology, and treatment remains controversial due to its rarity. Major reported SEDC cases are caused by leaking out of cerebrospinal fluid through a dural defect in the thecal sac forming an extradural cyst. Other reports describe non-communicating SEDC cases where the dural defect was not identified. We report a literature review on SEDC and the case of a 53 year­old female who presented with type IA extradural cyst with subarachnoid space communication. METHODS: Literature review, preoperative imaging and surgical technique. RESULTS: The extradural cyst was excised completely and the dural defect was repaired. After surgical decompression, neurological symptoms gradually recovered. CONCLUSIONS: The extradural arachnoid cyst is an uncommon entity. Preoperative imaging is one of the determining elements in orienting the therapeutic management of the SEDCs. The choice of the surgical technique must be the least invasive in order to avoid postoperative complications. Subtotal or complete excision of the cyst, followed by obliteration of the communication stalk and repair of the dural defect is the gold standard treatment.

Dorsum Sellae as Key Landmark in ETV With Disminished Prepontine Cistern: Technical Note and Case Series.

BACKGROUND AND OBJECTIVES: One of the key aspects in the surgical technique of endoscopic third ventriculostomy (ETV) is the perforation of the floor of the third ventricle because of the high risk of injuring vital structures located in that region. According to the standard technique, this perforation should be performed in the midline halfway between mammillary bodies and the infundibular recess to avoid damage to the structures. This can be performed without excessive complications when the diameter of the prepontine cistern is wide. However, in situations where the diameter is reduced (defined in the literature as having a prepontine interval [PPI] ≤1 mm), the probability of complications increases exponentially.In this article, we propose using dorsum sellae as a key point to safely perform ETV in patients with a decreased PPI, guiding the trajectory and its marking using neuronavigation. METHODS: A review was conducted on the latest 100 ETV procedures performed by our team in the past 5 years. The measurement of the PPI was conducted using archived preoperative MRI imaging studies, specifically between the dorsum sellae and the basilar artery. In cases where the PPI was ≤1 mm and, therefore, the use of the dorsum sellae was applied as a reference point, the technical results and procedural functions were documented. RESULTS: In the cohort, 7 patients with a PPI ≤1 mm were identified. In all 7 cases, fenestration of the tuber cinereum was successfully performed without causing vascular damage or associated complications. ETV was successful in 6 patients, with only one experiencing ETV failure necessitating the placement of a ventriculoperitoneal shunt. CONCLUSION: The utilization of the dorsum sellae as a reference point to perform ETV in reduced PPI constitutes a safe alternative to the classical technique.

Syringopleural shunt for refractory syringomyelia: how I do it.

BACKGROUND: Surgical treatment of syringomyelia is directed at the reconstruction of the subarachnoid space and restoration normal cerebrospinal fluid flow. Direct intervention on the syrinx is a rescue procedure and should be offered to patients with refractory syringomyelia. METHODS: We provide an overview on indications and technique of syringopleural shunt (SPS). The procedure involves the connection of syrinx with the pleural space using a lumboperitoneal shunt. The occurrence of a negative pressure inside the pleural compartment offers an appropriate gradient for drainage from the syrinx. CONCLUSIONS: The SPS allows for a safe and effective treatment of persistent syringomyelia when management of the underlying cause does not yield substantial improvement.

Neurenteric cyst of the craniovertebral junction treated to reduce recurrence using different strategies: Two case reports and a literature review.

RATIONALE: Neurenteric cysts are rare benign lesions that are usually located in the lower cervical and upper thoracic spine and extremely rare in the craniovertebral junction. It is generally challenging to completely remove the neurenteric cysts of the craniovertebral junction. We report the cases of 2 patients with neurenteric cyst in the ventral craniovertebral junction managed using different treatment strategies. PATIENT CONCERNS: The first patient was a 64-year-old man. He man was admitted with headache, posterior neck pain, and a tingling sensation in both the forearms. The second patient was a 53-year-old woman. She was admitted with tingling sensations and numbness in both the hands and feet. DIAGNOSES: Cervical spine magnetic resonance imaging showed 2 intradural extramedullary cystic lesions in case 1 and a C2 to C3 intradural extramedullary cystic mass in case 2. INTERVENTIONS AND OUTCOMES: The patient of the case 1 underwent a left C1 to C2 hemi-laminectomy and the cysts were completely removed. Eleven years after the surgery, there was no recurrence. In case 2, we performed a left C2 to C3 hemi-laminectomy and removed only a part of the outer membrane to enable sufficient communication with the surrounding normal subarachnoid space. After removing the cyst wall, the patient underwent C1 to 2 trans articular screw fixation to prevent cervical instability. Ten years after surgery, there was no recurrence of the cyst or new lesions. LESSONS: Clinicians should consider neurenteric cyst in the differential diagnosis of arachnoid cyst or epidermoid cyst. If performing a complete surgical removal is difficult, partial surgical removal, using a cysto-subarachnoid shunt and stabilization, such as screw fixation, could be an alternative treatment option to reduce the risk of mortality and morbidity.

The Microcisternal Drainage Technique.

BACKGROUND: Microsurgical dissection of arachnoid cisterns requires a combination of anatomic knowledge and microsurgical skill. The latter relies on experience and microsurgical dexterity, which depend on visual identification of cisternal microvasculature. We describe a novel standardized operative sequence to allow for bloodless arachnoid dissection when cisternal anatomy is challenging. METHODS: We used the reported technique in 1928 cases over the past 5 years (2018-2022). The outer arachnoid was incised to enter the cisternal space. A cotton pledget was placed in contact with an inner membrane and gently pushed laterally and superficially with the suction cannula at medium suction power. When the arachnoid membranes dried, arachnoid trabeculae were cut and microvasculature were released at the convexity of their loops and gently transposed off the dissection trajectory. The same principle was used to release parent and perforating arteries from the aneurysm dome. RESULTS: The microcisternal drainage technique enabled safe and efficient access through adhered arachnoid in all cases. A complex anterior communicating artery aneurysm in a 52-year-old lady demonstrated the use of the microcisternal drainage technique during access through the pericallosal cistern. This technique was used in all cases where cisternal dissection was needed. CONCLUSIONS: The microcisternal drainage technique uses deliberate and strategic suction, dynamic retraction, and nuanced scissor cuts to enable precise and bloodless microdissection of adherent arachnoid cisterns. This technique combines common neurosurgical maneuvers in a novel standardized sequence to improve efficiency and safety during arachnoid dissection.

Idiopathic Intracranial Hypertension with Disproportionately Enlarged Subarachnoid Space Hydrocephalus on Imaging.

The pathophysiology of idiopathic intracranial hypertension (IIH) and idiopathic normal-pressure hydrocephalus (iNPH) differs in terms of cerebrospinal fluid (CSF) pressure and imaging-related characteristics. A 51-year-old man presented with optic nerve papillary edema, visual disturbance, bilateral abducens nerve palsy, and a wide-based gait. Imaging showed characteristic findings of IIH and disproportionately enlarged subarachnoid space hydrocephalus (DESH) - characteristic of iNPH. A CSF examination revealed marked CSF hypertension. IIH with iNPH-like imaging features (DESH) was diagnosed, and ventriculoperitoneal shunt surgery was performed. Postoperatively, the visual acuity and visual field improved. This report also describes the distinct and overlapping pathophysiological mechanisms of IIH and iNPH.

Fourth ventricle to spinal subarachnoid space stenting in pediatric patients with refractory syringomyelia: case series and systematic review.

A series of 5 patients treated with the fourth ventricle to spinal subarachnoid space stent (FVSSS) is presented. Indication for surgery, surgical technique, pre-operative and post-operative images, and outcome are analyzed. A systematic review of the pertinent literature has also been performed. This is a retrospective cohort review of a series of 5 consecutive patients with refractory syringomyelia who underwent a fourth ventricle to spinal subarachnoid space shunt surgery. The surgical indication was based on the presence of refractory syringomyelia in patients already treated for Chiari malformation or in patients who developed scarring at the level of the outlets of the fourth ventricle following posterior fossa tumor surgery. The mean age at FVSSS was 11.30 ± 5.88 years. Cerebral MRI revealed crowded posterior fossa, with a membrane at the level of the foramen of Magendie. Spinal MRI showed syringomyelia in all patients. Before surgery, the averages of the craniocaudal and the anteroposterior diameter were 22.66 and 1.01 cm, respectively, whereas the volume was 28.16 cm3. The post-operative period was uneventful in 4 out of 5 patients; one child died on the 1st post-operative day due to complications unrelated to surgery. In remaining cases, syrinx marked improvement. The post-operative volume was 1.47 cm3 with an overall reduction of 97.61%. With regard to literature, 7 articles with a total of 43 patients were analyzed. After FVSSS, syringomyelia reduction was observed in 86.04% of cases. Three patients underwent reoperation due to syrinx recurrence. Four patients presented a catheter displacement, one a wound infection and meningitis and one CSF leak requiring placement of a lumbar drain. FVSSS is highly effective in restoring CSF dynamics, with dramatic improvement of syringomyelia. In all our cases, the volume of the syrinx was reduced by at least 90%, with improvement/resolution of accompanying symptomatology. This procedure should be reserved to patients in which other causes of gradient pressure between the fourth ventricle and subarachnoid space are excluded, for example, tetraventricular hydrocephalus. Surgical procedure is not simple, because it requires meticulous microdissection of cerebello-medullary fissure and upper cervical spine, in already operated patients. To avoid migration of the stent, it should be carefully sutured to the dura mater or thick arachnoid membrane.

Change in Morphological Features of Enlarged Subarachnoid Spaces Following Treatment in Idiopathic Normal Pressure Hydrocephalus.

BACKGROUND: Focally enlarged sulci (FES) are areas of proposed extraventricular fluid entrapment that may occur within idiopathic normal pressure hydrocephalus (iNPH) with radiographic evidence of disproportionately enlarged subarachnoid-space hydrocephalus (DESH), and should be differentiated from atrophy. PURPOSE: To evaluate for change in FES size and pituitary height after shunt placement in iNPH. STUDY TYPE: Retrospective. SUBJECTS: A total of 125 iNPH patients who underwent shunt surgery and 40 age-matched controls. FIELD STRENGTH/SEQUENCE: 1.5 T and 3 T. Axial T2w FLAIR, 3D T1w MPRAGE, 2D sagittal T1w. ASSESSMENT: FES were measured in three dimensions and volume was estimated by assuming an ellipsoid shape. Pituitary gland height was measured in the mid third of the gland in iNPH patients and controls. STATISTICAL TESTS: Wilcoxon signed-rank test for comparisons between MRI measurements; Wilcoxon rank sum test for comparison of cases/controls. Significance level was P < 0.05. RESULTS: Fifty percent of the patients had FES. FES volume significantly decreased between the pre and first postshunt MRI by a median of 303 mm3 or 30.0%. Pituitary gland size significantly increased by 0.48 mm or 14.4%. FES decreased significantly by 190 mm3 or 23.1% and pituitary gland size increased significantly by 0.25 mm or 6% between the first and last postshunt MRI. DATA CONCLUSION: Decrease in size of FES after shunt placement provides further evidence that these regions are due to disordered cerebrospinal fluid (CSF) dynamics and should not be misinterpreted as atrophy. A relatively smaller pituitary gland in iNPH patients that normalizes after shunt is a less-well recognized feature of altered CSF dynamics. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Development of normal pressure hydrocephalus following post-traumatic external hydrocephalus in an adult patient.

We report the case of 74-year-old patient suspected of post-traumatic external hydrocephalus (EH) following a mild traumatic brain injury with a progressive neurological decline and a concomitant enlargement of subarachnoid spaces without ventriculomegaly on CT scan. A lumbar puncture revealed raised ICP and a careful CSF withdrawal was performed, resulting in an immediate neurological improvement, confirming the diagnosis of EH. During the 20-month follow-up, the patient presented progressive signs of normal pressure hydrocephalus (NPH): gait and cognitive decline, ventriculomegaly and the lumbar infusion study confirmed disturbed CSF dynamics. The patient underwent a ventriculoperitoneal shunt surgery, resulting in a long-lasting improvement.

Traumatic Subarachnoid-Pleural Fistula with Pneumocephalus.

Traumatic subarachnoid-pleural fistula is an uncommon occurrence. We present a case of a patient sustaining a subarachnoid-pleural fistula after a gunshot wound to the neck, which ultimately resulted in substantial pneumocephalus. The patient underwent successful operative repair of the fistula with notable improvement and resolution of pneumocephalus.

Can preoperative brain imaging features predict shunt response in idiopathic normal pressure hydrocephalus? A PRISMA review.

PURPOSE: This systematic literature review aimed to identify brain computed tomography (CT) and magnetic resonance imaging (MRI) features that could be used to discriminate idiopathic normal pressure hydrocephalus (iNPH) shunt responders from non-responders. METHODS: PubMed, Embase, Web of Science, and Cochrane were searched following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only original research articles reporting preoperative CT and/or MRI features and iNPH shunt response evaluated by changes in gait, dementia, and urinary incontinence were included. Title and abstract screening and full-text article evaluation were done by two authors. Data on patient demographics and inclusion criteria, brain image evaluation, shunting methods, and shunt response evaluation were recorded. RESULTS: The search resulted in 1274 studies after removing duplicates. Twenty-seven studies were chosen for final review. Both structural (i.e., callosal angle, disproportionately enlarged subarachnoid space hydrocephalus (DESH), and temporal horn diameter) and physiological brain imaging (including aqueductal flow measurement and brain perfusion) had been examined. Fourteen out of 27 studies found no difference in any assessed imaging parameters between responders and non-responders, and none of the examined imaging parameters was repeatedly and consistently reported as significantly different between the two groups. CONCLUSIONS: No brain imaging parameters were consistently and repeatedly reported as different between iNPH shunt responders and non-responders.

Targeted detection and repair of a spinal dural defect associated with successful biochemical resolution of subarachnoid bleeding in classical infratentorial superficial siderosis.

BACKGROUND AND IMPORTANCE  : Classical infratentorial superficial siderosis (iSS) is characterised by repeated insidious bleeding into the subarachnoid space, leading to haemosiderin deposition within the subpial layers of the brainstem, cerebellum and spinal cord, sometimes with supratentorial involvement. Although nearly always associated with a dural defect (usually from previous trauma or neurosurgery) there is little evidence to support definitive investigation and management strategies. Here, we present a novel investigation strategy to identify a dural defect and subsequent successful surgical repair with biochemical resolution of subarachnoid bleeding. CLINICAL PRESENTATION: A 55-year-old gentleman presented with a 15-year progressive history of sensorineural deafness, followed by a slowly worsening gait ataxia. He had previously sustained cranio-spinal trauma. On examination there were features of myelopathy and ataxia. MRI demonstrated classical iSS, affecting cerebellum and cerebral cortices, with a cervicothoracic epidural CSF collection. Lumbar puncture (LP) revealed elevated ferritin 413 ng/mL and red cell count of 4160. Reverse CT myelography, a novel technique involving contrast injection into the collection, delineated a dural defect at the T9/T10 level that was not present on conventional myelography. Following surgical repair, repeat LP twelve months later demonstrated biochemical improvement (ferritin 18 ng/mL, red cells < 1). There was no further neurological deterioration in symptoms during eighteen months follow-up. CONCLUSION: We show the value of a rational targeted investigation pathway in identifying a surgically reparable dural defect underlying classical iSS. We also provide proof of concept that surgical repair can facilitate biochemical resolution of subarachnoid bleeding and might prevent progression of neurological disability.

Resolution of Primary or Recalcitrant Chiari-Associated Syringomyelia Requires Adequate Cerebrospinal Fluid Egress from the Fourth Ventricle.

Syringomyelia is often resistant to various treatment modalities.1 Chiari I malformations are associated with syringomyelia in approximately 69% of operative cases.2 Failure to resolve syringomyelia after Chiari decompression is common.3 The pathophysiology of Chiari-associated syringomyelia has been well studied, with Oldfield emphasizing the water-hammer mechanism, with treatment limited to bony decompression and duraplasty.4 On the other hand, capacious fourth ventricular drainage is thought to be essential for syrinx resolution. Persistence or progression of the syrinx after decompression is an indication for reoperation. Direct shunting of the syrinx is associated with high failure rates.1,5-7 The technique of shunting the fourth ventricle has been applied successfully in the pediatric population.3,8-10 We emphasize the need to ensure outflow from the fourth ventricle in Chiari decompressions associated with syringomyelia. In revisions to treat progressive syringomyelia after failed decompression, we undertake the following steps: 1) adequate lateral bony decompression,11-13 2) lysis of scar/adhesions around the cisterna magna, 3) opening the fourth ventricle outlet by releasing any web/adhesions, 4) insertion of a shunt from the fourth ventricle to the cervical subarachnoid space, and 5) bipolar coagulation of the lateral tonsillar pia to maintain patency of cerebrospinal fluid pathways.8 We favor autologous fascia or pericranium for expansile duraplasty, as the use of nonautologous materials may cause excessive scarring.14-16 In this video, we demonstrate these tenets in 3 cases of Chiari-associated syringomyelia, 2 revisions and 1 primary case, with excellent resolution of the syrinx (Video 1). The patients consented to surgery and publication of images.

[Diagnosis for Idiopathic Normal Pressure Hydrocephalus].

In aging societies, idiopathic normal-pressure hydrocephalus(iNPH)has emerged as an important disease that can negatively affect the activities of daily living among the elderly. Evidence supporting diagnosis and treatment has accumulated and, in Japan, the third edition of the iNPH treatment guideline was published in 2020. Through the promotion of multi-facility research efforts in Japan, diagnosis of iNPH has been based on characteristic phenomena including gait disturbance, overactive bladder, cognitive impairment, and disproportionately enlarged subarachnoid space hydrocephalus(DESH). In supplementary examinations, brain transformations associated with iNPH have been evaluated using modified magnetic resonance imaging methods. Moreover, studies aimed at elucidating the disease state in combination with biological information obtained from cerebrospinal fluid findings are in progress. However, the outcome prediction of shunt treatment for atypical iNPH(i.e., non-DESH iNPH)and coexisting nervous system abnormalities is also important. In these cases, determining indications for surgery is a particular challenge.