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Objective: Chiari malformation type I (CM-I) is frequent in children and remains a surgical challenge. Several techniques have been described for posterior fossa decompression. No decision algorithm has been validated, and strategies are highly variable between institutions. The goal of this study was to define therapeutic guidelines that take into consideration patient specificities., Methods: The authors retrospectively collected data from patients who were < 18 years of age, were diagnosed with CM-I, and were treated surgically between 2008 and 2018 in 8 French pediatric neurosurgical centers. Data on clinical features, morphological parameters, and surgical techniques were collected. Clinical outcomes at 3 and 12 months after surgery were assessed by the Chicago Chiari Outcome Scale. The authors used a hierarchical clustering method to define clusters of patients by considering their anatomical similarities, and then compared outcomes between surgical strategies in each of these clusters., Results: Data from 255 patients were collected. The mean age at surgery was 9.6 ± 5.0 years, syringomyelia was reported in 60.2% of patients, the dura mater was opened in 65.0% of patients, and 17.3% of patients underwent a redo surgery for additional treatment. The mean Chicago Chiari Outcome Scale score was 14.4 ± 1.5 at 3 months (n = 211) and 14.6 ± 1.9 at 12 months (n = 157). The hierarchical clustering method identified three subgroups with potentially distinct mechanisms underlying tonsillar herniation: bony compression, basilar invagination, and foramen magnum obstruction. Each cluster matched with specific outcomes., Conclusions: This French multicenter retrospective cohort study enabled the identification of three subgroups among pediatric patients who underwent surgery for CM-I, each of which was associated with specific outcomes. This morphological classification of patients might help in understanding the underlying mechanisms and providing personalized treatment.

Cranial nerve (CN) disorders are the foremost symptoms in cerebellopontine angle (CPA) and petroclival area (PCA) epidermoid cysts (EC).The aim of this work was to  assess the long-term surgical results on CN function and tumor control in these patients. We performed a retrospective cohort study about 56 consecutive patients operated on for a CPA or PCA EC between January 2001 and July 2019 in six participating French cranial base referral centers. Sixteen patients (29%) presented a PCA EC and 40 a CPA EC (71%). The median clinical and radiological follow-up was 46 months (range 0-409). Preoperative CN disorders were present in 84% of patients (n = 47), 72% of them experienced CN deficits improvement at the last follow-up consultation (n = 34): 60% of cochlear and vestibular deficits (n = 9/15 in both groups), 67% of trigeminal neuralgia (n = 10/15), 53% of trigeminal hypoesthesia (n = 8/15), 44% of lower cranial nerve disorders (n = 4/9), 38% of facial nerve deficits (n = 5/8) and 43% of oculomotor deficits (n = 3/7) improved or were cured after surgery. New postoperative CN deficits occurred in 48% of patients (n = 27). Most of them resolved at the last follow-up, except for cochlear deficits which improved in only 14% of cases (n = 1/7). Twenty-six patients (46%) showed evidence of tumor progression after a median duration of 63 months (range 7-210). The extent of resection, tumor location, and tumor size was not associated with the occurrence of new postoperative CN deficit or tumor progression. A functional nerve-sparing resection of posterior fossa EC is an effective strategy to optimize the results on preexisting CN deficits and reduce the risk of permanent de novo deficits., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Abstract: We report the case of a 75-year-old man with history of prostate cancer whose left intracavernous lesion was successfully characterized by 3 PETs performed successively with different tracers. This poorly characterized tumor was initially discovered on an MRI conducted to investigate an acute diplopia and slowly growing during follow-up. On 18F-FDG PET, the lesion showed no significant uptake, and no extracranial lesion was found nor did it have increased 68Ga-DOTATOC uptake. Finally, this tumor displayed a high 18F-choline uptake, and no extracranial lesion was revealed with this tracer. The diagnosis of schwannoma without malignancy criterion was proven by biopsy., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Pneumosinus dilatans of the sphenoid sinus is a rare disorder which can be responsible for visual impairment and blindness. We present the case of an adolescent female who experienced progressive decrease in right-eye vision over 2 years. CT scan of the head showed an extensive pneumatization of the sphenoid bone extending to the lesser wing of the sphenoid and to the anterior clinoid process on the right side. MRI revealed right nerve atrophy in the optic canal and in the posterior part of the orbit. A surgical decompression of the right optic canal was performed via an intradural fronto-pterional approach. Postoperatively, her vision worsened, and at 3 years the patient was able to count fingers at 2.5 m. Our case and literature review of symptomatic sphenoidal pneumosinus dilatans confirmed that visual prognosis in such cases depended on the preoperative visual status. Early surgical decompression should be proposed whenever possible, before signs of severe visual disorders and optic atrophy., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Dysplastic gangliocytoma of the cerebellum (DGC), also called Lhermitte-Duclos disease, is a rare lesion of the posterior fossa consisting of a diffuse hypertrophy of the cerebellar cortex. DGC frequently presents in young adults and rarely in childhood. Only 3 cases have been previously described in newborns. We present an uncommon case of DGC which was diagnosed in utero. The radiological presentation prenatally and at birth was similar to a heterotopic neuroglial brain tissue. MRI aspects evolved from T1/T2 isointense signals to hypoT1 and hyperT2 signals at the age of 1 year. The girl was then operated on total removal of the lesion which was performed with no postoperative complication. Genetics did not demonstrate any germline PTEN mutation or family history suggesting Cowden disease. Two years later, the child was doing well and MRI confirmed complete resection. This case illustrates the difficulties of diagnosing intracranial lesions in foetuses and newborns. Physicians caring for pregnant women and pediatrics should be aware that neoplasm-like lesions such as DGC may present as hamartomas. Surgical resection could then be discussed whenever possible.

Purpose: Our study aimed to evaluate potential risk factors for the development of FDICA after suprasellar tumor resection., Materials and Method: After reviewing all cases of pediatric patients who benefited from a suprasellar lesion resection in our two medical institutions, we found 6 patients with a FDICA. Surgical approach strategy (pterional or subfrontal approaches) was noted. Postoperative cranial MRI was performed in each patient 3 months after surgery and every year. When a FDICA occurred, MRI was performed 6 months after the diagnosis and 1 year later to detect any progression., Results: There were 6 males with a mean age at treatment of 11 years (6 to 15). Pterional approach was performed in these 6 patients. At the 2 institutions, we have done at least 50 pterional craniotomies for suprasellar lesion resection. No FDICA was reported after subfrontal approach in 27 consecutive pediatric patients operated on from a craniopharyngioma. The delay between the surgery and the diagnosis of the FDICA was 9 months (3 to 17 months). No symptoms related to the FDICA were recorded. The mean maximal diameter of the aneurysm was 14 mm (10 to 21). ICA bifurcation was involved in 2 cases. Asymptomatic FDICA progression was noted in 2 cases but no treatment was proposed., Conclusion: The pathogenesis of FDICA is unclear, and might involve arterial wall necrosis caused by postoperative arachnoid fibrosis which might be worsened by the pterional approach.

Objective: The objective of this study was to compare the tumour control and facial nerve outcome according to the therapeutic strategy, that is extent of resection and post-operative radiotherapy., Design: Retrospective study of patients with a giant vestibular schwannoma surgically treated from 4 academic skull base centres., Setting: Extent of resection, neurological complications, facial nerve function, MRI follow-up and occurrence of complementary treatment were reviewed., Participants: Sixty patients were included from 2000 to 2018., Main Outcome Measures: Primary end points were comparison the tumour control rate and the post-operative House-Brackmann grade at last follow-up according to the extent of tumour removal (ie total or subtotal removal). Secondary end points were assessment risk factors of poor facial nerve function and comparison complication rate according to extent of tumour removal., Results: Sixty patients had initial surgery at diagnosis. A total resection was realised in 21 cases and a subtotal resection in 39 cases. Thirteen patients needed further treatment. One patient had a recurrence and needed a second surgery 108 months after the initial total resection surgery. Twelve patients underwent post-operative radiotherapy, for an evolutive residual tumour. Tumour control was more successful in the total resection group (log-rank test, P = .015). There was no tumour recurrence after post-operative radiotherapy. The facial nerve outcome was significantly better in the subtotal resection group (Mean House-Brackmann grade at last follow-up: 2.2 ± 1.9) than in the total resection group (House-Brackmann grade: 3.5 ± 2.2) (P = .033). Vestibular schwannoma with a cystic component had better facial nerve outcome (P = .0082). Other than facial paralysis, neurological complications were observed in six patients (10% of patients): lower cranial nerves dysfunction in five cases and hemiparesis in one case., Conclusions: Subtotal resection of giant vestibular schwannomas leads to favourable tumour control and facial nerve function and therefore seems to be a valuable strategy., (© 2020 John Wiley & Sons Ltd.)

Purpose: Rupture of arachnoid cysts (AC) in the subdural space after trauma may cause a subacute/chronic subdural hematoma or a hygroma. Treatment of this complication still remains controversial, and no consensual strategy is to date clearly proposed. In this study, the authors evaluated the clinical and radiological evolution of patients treated by a subduro-peritoneal shunt for symptomatic subdural collections complicating ruptured AC., Methods: Medical records of the 10 patients treated at our institution between January 2005 and December 2018 for a subdural collection associated with an intracranial AC were reviewed. Subduro-peritoneal shunts consisted of low-pressure valves from 2005 to 2012 (6 cases) and medium-pressure valves after 2012 (4 cases)., Results: A benign head trauma was retrospectively found in the history of 8 patients. The mean time to diagnosis ranged from 15 days to 5 months. Symptoms resulted mainly from intracranial hypertension. Six patients had an ipsilateral hygroma to the AC, 2 patients had a bilateral hygroma predominantly to the AC side, and 2 patients presented an ipsilateral chronic subdural hematoma. Arachnoid cysts were classified as Galassi I in 5 cases and Galassi II in 5 cases. Patients with chronic subdural hematoma were given a medium-pressure valve. Patients with subdural hygroma received a low-pressure valve in 6 cases and a medium-pressure valve in 2 cases. There were no complications during surgical procedures. All patients were rapidly free of symptoms after surgery and were discharged from hospital 1 to 4 days postoperatively. The subdural collection completely disappeared in all cases. In the long term, only 2 patients with low-pressure valves underwent shunt removal without any consequences, while a second surgical procedure was necessary to treat recurrence of intracranial hypertension in the 4 remaining cases. All the medium-pressure valves were removed without problems. The size of the AC was reduced in 3 cases, remained stable in 4 cases, and increased in 3 cases. No patients experienced recurrence of subdural collection during follow-up., Conclusions: Medium-pressure subduro-peritoneal shunts should be considered as part of the arsenal of surgical strategy in symptomatic ruptured AC in the subdural space. The procedure is simple with a very low morbidity, and it allows rapid improvement of symptoms. Although the shunt is located in the subdural space, we strongly recommend avoiding devices which may create an overdrainage and expose the patient to shunt dependency such as low-pressure shunts.

Background: Recent literature showed that analysis of interruptions can contribute to evaluating the care process in the operating room, and thus, understanding potential errors that may occur during surgical procedures. The aim of this comprehensive review was to summarize current knowledge on the description and impact of interruptions in surgery., Material and Methods: A literature search was conducted according to a set of criteria in the databases MEDLINE, BASE, Cochrane's Library, and PsycINFO., Results: 41 articles were included. Two main methodological approaches were found, observational in the OR, or controlled in an experimental simulated environment. Interruptions in the OR were manifold, and several classifications were used. The severity of interruptions differed according to the category of the interruptions. Interruptions were influenced by team familiarity and the expertise of the surgical team; high team familiarity and a high level of expertise decreased the frequency of interruptions. However, our literature search lacked controlled studies carried out in the OR. Interruptions seemed to increase the workload and stress of the surgical team and impair nontechnical skills, but no clear evidence of this was advanced., Conclusions: Interruptions are probably risk factors for errors in the operating room. However, there is as yet no clear evidence of the association of interruption frequency with errors in the operating room. There is a need to define and target interruptions, which should be reduced by putting safeguards in place, thereby allowing those which could be beneficial and neglecting those with no potential consequences., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The gold standard treatment of spinal dural arteriovenous fistulas (SDAVF) is surgical exclusion. The main surgical challenge is to localize the origin of the shunting vein and to ensure its complete exclusion. In that context, intra operative angiography technologies have been developed, such as fluorescein video angiography (FVA). The objective of this preliminary study was to assess the utility of FVA in SDAVF surgery through a short surgical series. We retrospectively studied the cases of six patients who had a FVA for a SDAVF. FVA was performed after dural opening and visualization of the suspected shunting vein. In 5 cases, FVA was performed after ligation to ensure the complete exclusion. In 2 cases, FVA was performed before the ligation to confirm the localization of the shunt. In 1 case, FVA was performed before and after ligation. FVA was judged useful in all cases to localize the origin of the shunting vein. FVA permitted to ensure the complete exclusion after ligation. No anaphylactic events were noticed. Our preliminary study suggests that fluorescein video angiography is feasible and helpful for SDAVF surgery., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Hamstring spasticity can bring about a flexion deformity of the knee, liable to cause disability. Surgical treatment by selective neurotomies of the sciatic nerve branches leading to the hamstring muscles may then be indicated. Few studies have investigated the precise origin of these branches on the sciatic nerve, describing the innervation pattern of the hamstring muscles. Further anatomical data are needed to enhance surgical techniques in neurotomies of the sciatic nerve branches, to define the best incision and surgical approach and what section and length of the SN need to be exposed. Therefore, we performed an anatomical study to: (1) define a surgical approach to perform selective neurotomies of the sciatic nerve branches for hamstring spasticity?(2) whether the anatomical variants of the hamstring innervation have been identified?, Hypothesis: Our anatomical data could lead to the definition of an approach to the sciatic nerve for the purpose of selective neurotomy., Material and Methods: Twenty posterior compartments of the thigh were dissected. We counted each branch of the sciatic nerve leading to the hamstring and described their arising point using the centre of the lateral surface of the great trochanter and the lower edge of the gluteus maximus muscle as main anatomical landmarks. We also described the presence of branch divisions and their muscular penetrating points., Results: The mean distances between the center of the lateral surface of the great trochanter and the emergence of branches from the SN were: 2.2±3.6cm (-5 to 9cm) for the long head of the biceps femoris muscle, 2.3±3cm (-4 to 10cm) for the semitendinosus muscle, and 2.2±3cm (-5 to 8cm) for the semimembranosus muscle. No branches originated from the sciatic nerve below the lower edge of the gluteus maximus muscle. In summary the branches innervating the hamstrings originated from the SN within an interval of 15cm (5cm above and 10cm below the centre of the lateral surface of great trochanter). The average number of sciatic nerve branches for the hamstring muscles was 4.7 (minimum: 3; maximum: 6) with 1.8 branches for the long head of the biceps [1 in 7/20 (35%), 2 in 10/20 (50%), and 3 in 3/20 (15%)], 1.5 branches for the semitendinosus [1 in 11/20 (55%) and 2 in 9/20 (45%)], 1.4 branches for the semimembranosus [1 in 12/20 (60%) and 2 in 8/20 (40%)]. No branches had a common origin with cutaneous nerves., Discussion: This anatomical study enabled us to propose an approach to exposing the sciatic nerve in order to perform a selective neurotomy: horizontal cutaneous incision on the gluteal fold, incision of the lower edge of the gluteus maximus, exposure of the sciatic nerve to a distance of 10cm below the great trochanter, and visualization of the nerve branches to the hamstring muscles. Exposure of the nerve above the great trochanter is not necessary because the branches which emerge from the SN above the great trochanter are still contiguous with the SN., Level of Evidence: IV: prospective study without control., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Objective: Spinal dural arteriovenous fistulas (SDAVFs) are rare vascular spinal malformations. According to the reported data, surgery seems to result in better occlusion rates than endovascular treatment. However, the post-treatment evolution of neurological symptoms stratified by the treatment remains unknown. The main objective of the present study was to compare the clinical outcomes for patients according to the treatment method., Methods: The data from 63 patients with SDAVFs from 2000 to 2017 at 4 academic neurosurgical departments were retrospectively analyzed. Preoperative and postoperative examination neurological status was assessed using the Aminoff-Logue scale (ALS), which evaluates gait and micturition disturbances. Initial occlusion, late recurrence, and complications of the 2 techniques were also reviewed., Results: Patients who had undergone surgery and embolization improved clinically on the ALS (P = 0.0009), and no significant differences were found between the 2 techniques. Subgroup analysis using the ALS showed that patients who had undergone surgery and embolization without late recurrence improved (P < 0.0001 and P = 0.0334, respectively) and that patients who had undergone surgery or embolization with late recurrence did not improve. The initial occlusion rate was in favor of surgery, with 91.3% versus 70% for endovascular treatment (P = 0.050). The late recurrence rate was higher for embolization (21.4% vs. 9.1% for surgery; P = 0.28)., Conclusions: Surgery can be proposed as first-line treatment of SDAVFs after multidisciplinary discussion between neurosurgeons and neuroradiologists. The development of late recurrence negatively affects the neurological outcome of patients., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Meningiomas that compress the optic nerve (ON) can lead to different visual outcomes depending on the segment of ON affected (intraorbital, canalicular, and intracranial). In this study, we performed a comprehensive comparison of the management options (surgery, radiation, or observation alone) for meningiomas compressing the ON, categorized by location and relation to the ON., Methods: MEDLINE, EMBASE, Web of Science, and the Cochrane Database of Systematic reviews databases were searched according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Data were extracted from the articles regarding anatomic location, initial visual impairment, surgical procedure, visual outcome, morbidity and mortality, gross total removal, and requirement for postoperative radiotherapy., Results: Of the 47 articles eligible for full-text reading, 9 surgical studies met our inclusion criteria. Data from 317 patient cases were extracted. In patients in whom the intracranial segment of the ON was impaired in isolation, 49% experienced visual improvement after surgery. When the meningioma affected the canalicular segment or intraorbital segment, visual improvement after surgery was 31% and 11%, respectively. Of patients who underwent surgery for the intraorbital segment of the ON, 56% experienced a decline in visual outcome., Conclusions: When a neurosurgeon deals with a meningioma compressing the ON, opening the optic canal is suggested if invasion is suspected on the preoperative imaging. Extra caution should be used when operating on meningiomas with ON sheath adhesion, given the higher evidence of postoperative visual worsening., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Brain arteriovenous malformations (AVM) are complex and highly challenging lesions, for which intra-operative indocyanin green fluorescence video angiography is widely used. Fluorescein video angiography (FVA) recently appeared as an alternative technique but the feasibility and usefulness of this technique is yet uncertain. This short series reports our preliminary experience of FVA in intracranial AVM surgery. We retrospectively studied the cases of seven patients who had FVA for an AVM surgery. The primary objective of this study was to assess the utility of FVA as judged by the surgeon. Secondary objectives were the evaluation of the tolerance of bolus injection of fluorescein in the context of cranial surgery, the comparison with ICG and the rate of complete removal. For each of the seven patients, FVA was performed after exposure of the AVM and before the resection; it was visualized directly through the eyepieces of the microscope and helped in the identification of arterial feeders and draining veins. In one case, post-resection FVA allowed the visualization of a residual shunt and the resection was completed. In two cases, ICG and FVA brought comparable information. The resection was complete in all cases, confirmed by post-operative imaging. There was no anaphylactic complication. This preliminary work suggests that FVA is a simple and well tolerated technique, comparable to ICG angiography. Prospective and larger studies are needed to confirm the clinical benefit of this tool., (Copyright © 2018 Elsevier Ltd. All rights reserved.)