The role of surgical disconnection for posterior fossa pial arteriovenous fistulas and dural fistulas with pial supply: an illustrative case series.

BACKGROUND: Pial arteriovenous fistulas (pAVFs) are rare vascular malformations characterized by high-flow arteriovenous shunting involving a cortical arterial supply directly connecting to venous drainage without an intermediate nidus. Dural arteriovenous fistulas (dAVFs) can infrequently involve additional pial feeders which can introduce higher flow shunting and increase the associated treatment risk. In the posterior fossa, arteriovenous fistula (AVF) angioarchitecture tends to be particularly complex, involving either multiple arterial feeders-sometimes from both dural and pial origins-or small caliber vessels that are difficult to catheterize and tend to be intimately involved with functionally critical brainstem or upper cervical cord structures. Given their rarity, published experience on microsurgical or endovascular treatment strategies for posterior fossa pAVFs and dAVFs with pial supply remains limited. METHODS: Retrospective chart review from 2019-2023 at a high-volume center identified six adult patients with posterior fossa pAVFs that were unable to be fully treated endovascularly and required microsurgical disconnection. These cases are individually presented with a technical emphasis and supported by comprehensive angiographic and intraoperative images. RESULTS: One vermian (Case 1), three cerebellopontine angle (Cases 2-4) and two craniovertebral junction (Cases 5-6) posterior fossa pAVFs or dAVFs with pial supply are presented. Three cases involved mixed dural and pial arterial supply (Cases 1, 4, and 6), and one case involved a concomitant microAVM (Case 2). Endovascular embolization was attempted in four cases (Cases 1-4): The small caliber and tortuosity of the main arterial feeder prevented catheterization in two cases (Cases 1 and 3). Partial embolization was achieved in Cases 2 and 4. In Cases 5 and 6, involvement of the lateral spinal artery or anterior spinal artery created a prohibitive risk for endovascular embolization, and surgical clip ligation was pursued as primary management. In all cases, microsurgical disconnection resulted in complete fistula obliteration without evidence of recurrence on follow-up imaging (mean follow-up 27.1 months). Two patients experienced persistent post-treatment sensory deficits without significant functional limitation. CONCLUSIONS: This illustrative case series highlights the technical difficulties and anatomical limitations of endovascular management for posterior fossa pAVFs and dAVFs with pial supply and emphasizes the relative safety and utility of microsurgical disconnection in this context. A combined approach involving partial preoperative embolization-when the angioarchitecture is permissive-can potentially decrease surgical morbidity. Larger studies are warranted to better define the role for multimodal intervention and to assess associated long-term AVF obliteration rates in the setting of pial arterial involvement.

How I do it: dorsolateral approach for ventrolateral intramedullary cavernoma.

BACKGROUND: For small and lateral lesions, in order to avoid postoperative sequelae related to dorso-median myelotomy, we propose to describe the use of a ventrolateral approach for intramedullary lesions. METHOD: Performing this approach entails that the denticulate ligament is cut from its dural attachment and retracted. Rotation of the spinal cord must be achieved with great caution and under electrophysiological monitoring. After pia mater incision, hydrodissection is useful to gently dissect the cavernoma and promote a cleavage plane. CONCLUSION: In the case of lateral intramedullary lesions, using this approach maximized the absence of postoperative deficit.

Navigation-guided clipping of a de novo aneurysm associated with superficial temporal artery-middle cerebral artery bypass combined with indirect pial synangiosis in a patient with moyamoya disease.

De novo aneurysms associated with superficial temporal artery (STA)-middle cerebral artery (MCA) bypass are an extremely rare complication of direct revascularization surgery for moyamoya disease (MMD). The basic pathology of MMD includes fragility of the intracranial arterial wall characterized by medial layer thinness and waving of the internal elastic lamina. However, the incidence of newly formed aneurysms at the site of anastomosis currently remains unknown. Among 317 consecutive direct/indirect combined revascularization surgeries performed for MMD, we encountered a 52-year-old woman manifesting a de novo aneurysm adjacent to the site of anastomosis 11 years after successful STA-MCA bypass with encephalo-duro-myo-synangiosis (EDMS). Although the patient remained asymptomatic, the aneurysm gradually increased in diameter to more than 6 mm with the formation of a daughter sac, and a computational fluid dynamic study revealed low wall shear stress at the aneurysm dome. The patient underwent microsurgical clipping of the aneurysm using a neuro-navigation system that permitted the minimally invasive dissection of the temporal muscle flap used for EDMS at the site of the aneurysm without affecting pial synangiosis. The aneurysm was successfully occluded using a titanium clip without complications. The postoperative course was uneventful, and the patient was discharged without neurological deficits. De novo aneurysms associated with STA-MCA bypass for MMD may be safely treated with microsurgical clipping, even in cases initially managed by a combined revascularization procedure that includes complex pial synangiosis. We recommend the application of the neuro-navigation system for the maximum preservation of pial synangiosis during this procedure.

Outcome following multiple subpial transection in Landau-Kleffner syndrome and related regression.

OBJECTIVE: To determine whether multiple subpial transection in the posterior temporal lobe has an impact on long-term outcome in children who have drug-resistant Landau-Kleffner syndrome (LKS) or other "electrical status epilepticus during sleep" (ESES)-related regression. Given the wide variability in outcomes reported in the literature, a secondary aim was to explore predictors of outcome. METHODS: The current study includes a surgery group (n = 14) comprising patients who underwent multiple subpial transection of the posterior temporal lobe and a nonsurgery comparison group (n = 21) comprising patients who underwent presurgical investigations for the procedure, but who did not undergo surgery. Outcomes were assessed utilizing clinical note review as well as direct assessment and questionnaires. RESULTS: The distribution of nonclassical cases was comparable between groups. There were some differences between the surgery and nonsurgery groups at presurgical investigation including laterality of discharges, level of language impairment, and age; therefore, follow-up analyses focused on change over time and predictors of outcome. There were no statistically significant differences between the groups in language, nonverbal ability, adaptive behavior, or quality of life at follow-up. There was no difference in the proportion of patients showing improvement or deterioration in language category over time for either group. Continuing seizures and an earlier age of onset were most predictive of poorer quality of life at long-term follow-up (F2,23 = 26.2, p = <0.001, R(2) = 0.714). SIGNIFICANCE: Both surgery and nonsurgery groups had similar proportions of classic LKS and ESES-related regression. Because no significant differences were found in the changes observed from baseline to follow-up between the two groups, it is argued that there is insufficient evidence to suggest that multiple subpial transection provides additional benefits over and above the mixed recovery often seen in LKS and related regressive epilepsies.

Intracranial pial fistulas in pediatric population. Clinical features and treatment modalities.

PURPOSE: The purpose of the study is to describe the clinical manifestations and treatment modalities of patients having intracranial pial arteriovenous fistulas (PAVFs). METHODS: We retrospectively analyzed the cases of PAVFs from January 2004 to December 2013. Medical charts, diagnostic images, surgical, and endovascular reports were reviewed retrospectively during each of the procedures and follow-up. We recorded patient demographics, clinical presentation, treatment modalities, and outcome. RESULTS: Ten patients with single PAVFs were identified, one of them with multiple holes. The median age was 7.5 years old (20 days to 14 years). Six patients were male (60% of cases). Four PAVFs were localized in the posterior fossa, and six were supratentorial (60%). Two patients had intracranial bleeding, three presented seizures, one was studied for chronic headaches, three manifested by growth retardation, one had hydrocephalus, and one had a congestive heart failure (CHF) and vein of Galen aneurysmal malformation (VGAM). The latter did not improve after embolization and died few days later. Endovascular therapy was used in eight, whereas two patients were surgically managed. Total occlusion of the fistula was achieved in all cases. CONCLUSIONS: PAVF affects pediatric population at different ages with miscellaneous clinical manifestations. Endovascular treatment is safe and effective when the venous side of the fistula can be occluded.

Intracranial pial arteriovenous fistula in infancy: a case report and literature review.

Intracranial pial arteriovenous fistulas (AVF) are rare vascular malformation especially in the first 2 years of life. The pathology in this age group is associated with greater morbidity and mortality. We report a rare case of 36-day-old male infant with a pial AVF associated with an arterial aneurysm, who presented with intraventricular hemorrhage and hydrocephalus. In addition, an online review of the literatures on pediatric pial AVF was performed using PubMed on published case reports and articles from 1980 to April 2013.

Microsurgical resection of cervical spinal arteriovenous malformation: the pial resection technique.

We present the case of a 26-year-old female patient who had two episodes of sudden, left, upper and lower extremity paresthesias and weakness, which resolved completely after 5 months. After recovery, she presented for evaluation. Imaging demonstrated a C3-C6 intra- and extra-axial arteriovenous malformation (AVM) with spinal cord compression and edema. A spinal angiogram showed arterial feeders arising from both vertebral arteries and from the right ascending pharyngeal artery. The AVM had been partially embolized after her first bleeding episode. She underwent C3-C6 laminoplasty and microsurgical resection of the AVM. After locating the main arterial feeders and draining veins, the malformation was resected using the pial resection technique. A postoperative spinal angiogram demonstrated gross total resection. Video used with permission from Barrow Neurological Institute. The video can be found here: http://youtu.be/JbbIwCTUsuI.

Occipital pial synangiosis.

BACKGROUND: Indirect revascularization techniques for posterior circulation moyamoya are infrequently described in the literature given the relative rarity of the disease process, particularly in the best candidates for indirect approaches-children. METHODS: We present a detailed, illustrated video demonstration of the occipital pial synangiosis procedure performed in a 5-year-old child. CONCLUSION: The specific advantages of the pial synangiosis technique-suturing the donor vessel to the pia and a wide arachnoidal opening-can be successfully applied to posterior circulation indirect revascularization. KEY POINTS: • Perioperative hydration and aspirin limit the risk of perioperative stroke. • Pain control and maintained normocapnea limit the risk of perioperative ischemic events. • The posterior auricular artery may be an alternative donor vessel. • The donor vessel is dissected from distal to proximal; forceps protect it during skin incision. • The donor vessel is dissected along a generous length to minimize tension. • Coagulation of the dura is limited as meningeal vessels may serve as synergistic collaterals. • A wide arachnoidal opening facilitates the ingrowth of collateral vessels. • Suturing the donor vessel to the pia ensures it remains well apposed to the brain surface. • The dura is left open to encourage ingrowth of collateral vessels and limit tension on the donor vessel. • EEG monitoring is a crucial adjunct.

Impact of Cerebral Revascularization on Pial Collateral Flow in Patients With Unilateral Moyamoya Disease Using Quantitative Magnetic Resonance Angiography.

BACKGROUND AND OBJECTIVES: Moyamoya disease (MMD) is a chronic steno-occlusive disease of the intracranial circulation that depends on neoangiogenesis of collateral vessels to maintain cerebral perfusion and is primarily managed with cerebral revascularization surgery. A quantitative assessment of preoperative and postoperative collateral flow using quantitative magnetic resonance angiography with noninvasive optimal vessel analysis (NOVA) was used to illustrate the impact of revascularization on cerebral flow distribution. METHODS: A retrospective review of patients with unilateral MMD who underwent direct, indirect, or combined direct/indirect cerebral revascularization surgery was conducted between 2011 and 2020. Using NOVA, flow was measured at the anterior cerebral artery (ACA), ACA distal to the anterior communicating artery (A2), middle cerebral artery (MCA), posterior cerebral artery (PCA), and PCA distal to the posterior communicating artery (P2). Pial flow (A2 + P2) and collateral flow (ipsilateral [A2 + P2])-(contralateral [A2 + P2]) were measured and compared before and after revascularization surgery. Total hemispheric flow (MCA + A2 + P2) with the addition of the bypass graft flow postoperatively was likewise measured. RESULTS: Thirty-four patients with unilateral MMD underwent cerebral revascularization. Median collateral flow significantly decreased from 68 to 39.5 mL/min ( P = .007) after bypass. Hemispheres with maintained measurable bypass signal on postoperative NOVA demonstrated significant reduction in median collateral flow after bypass ( P = .002). Median total hemispheric flow significantly increased from 227 mL/min to 247 mL/min ( P = .007) after bypass. Only one patient suffered an ipsilateral ischemic stroke, and no patients suffered a hemorrhage during follow-up. CONCLUSION: NOVA measurements demonstrate a reduction in pial collateral flow and an increase in total hemispheric flow after bypass for MMD, likely representing a decrease in leptomeningeal collateral stress on the distal ACA and PCA territories. Further studies with these measures in larger cohorts may elucidate a role for NOVA in predicting the risk of ischemic and hemorrhagic events in MMD.

Surgical flow disconnection of cerebral pial dual-channel arteriovenous fistula with a large varix: the role of anti-platelet agent or anti-coagulation therapy.

INTRODUCTION: Intracranial pial arteriovenous fistula (AVF) is a rare cerebrovascular lesion, and the literature is sparse. Most authors insist that simple disconnection of arteriovenous shunting is enough to treat intracral single-channel pial AVF in most cases, either by microsurgery or endovascular embolization without resection of entire vascular malformation. DISCUSSION: We report an insidious onset of peri-lesional edema formation after abrupt disconnection of AVF shunting with surgical arterial ligation. Treatment entailed anti-platelet and anti-coagulation agent to slow down thrombus formation in intracranial dual-channel pial AVF. We suggest that slowing down thrombus formation in the large varix with anti-platelet and/or anti-coagulation agents seems to be necessary in case of abrupt disconnection of shunting in intracranial single- or dual-channel pial AVF to prevent postoperative cerebral edema or infarction.

The distribution of arachnoid membrane within the velum interpositum.

BACKGROUND: There is as yet little knowledge as to the arachnoid architecture within the velum interpositum. The aim of this study was to clarify the distribution of the arachnoid membrane within the velum interpositum and its relationship with the arachnoid envelope over the pineal region. METHODS: In seven adult cadaver heads, histological sections of the third ventricle roof, stained with Masson's trichrome stains, were studied under light microscopy. RESULTS: Within the velum interpositum, there are two arachnoid layers. The dorsal layer of arachnoid membrane envelops the internal cerebral veins and fixes them to the surrounding tela choroidea as well as the ventral arachnoid layer. The ventral layer of arachnoid membrane is a direct anterior extension of the arachnoid envelope over the pineal region and covers the midline inferior layer of tela choroidea. Both arachnoid layers end near the foramen of Monro. CONCLUSIONS: The membranous roof of the third ventricle comprises two layers of the tela choroidea and two arachnoid layers. These two arachnoid layers are derived from the arachnoid envelope over the pineal region.

Efficacy of spinal pia mater incision and laminoplasty combined with internal fixation for old spinal cord injury.

OBJECTIVE: To evaluate the clinical efficacy of incising spinal pia mater to relieve pressure and unilateral open-door laminoplasty with internal screw fixation for treatment of the dated spinal cord injury. METHODS: From March, 2009 to July, 2010, 16 cases with chronic cervical cord injury underwent spinal dura mater incision and unilateral open-door laminoplasty with internal screw fixation. Nerve functions of pre- and postoperation were evaluated by Frankel classification and the Japanese Orthopaedic Association (JOA) scale.The improvement rate of JOA score at the indicated time was recorded. RESULTS: Postoperative Frankel classification rating of 16 patients improved obviously.JOA scores at the 1st month, 3rd month, 6th month, and 12th month after surgery were 7.9 ± 2.3, 8.5 ± 1.6, 8.9 ± 2.1, and 12.4 ± 2.5, respectively, and significantly increased compared with that prior to surgery (5.5 ± 0.6). At the end of follow-up period, JOA score was significantly higher than that of pre-treatment (P<0.05). The recovery was relatively rapid during the first 3 months following the surgery, then entered a platform period. CONCLUSION: It is effective for patients with dated spinal cord injury to undergo spinal decompression and laminoplasty.

Pial arteriovenous fistula: a review of literature.

Pial arteriovenous fistula (AVF) is a rare vascular lesion, with less than 120 reported cases in the English literatures (Hoh et al., Neurosurgery 2001;49(6):1351). The angio-architecture, clinical course and therapeutic options are all different from arteriovenous malformation (AVM), dural AVM or other intracranial vascular lesions. A review of literatures to analyse the clinical course of pial AVF was carried out. The presence of varix dictates the clinical course and presentation. Paediatric type had high percentage of varix, and mass effect as clinical presentation while the adult type usually manifest by haemorrhage. Disconnection of direct shunting, either by endovascular or surgically, is sufficient to achieve successful treatment; therefore, total resection of the lesion is unnecessary.

Resection of Cervical Intradural Extramedullary Melanoma Metastasis with Pial Invasion: 2-Dimensional Operative Video.

Intradural extramedullary metastatic melanoma is a rare entity with only 13 other cases reported in the literature.1 Of these, only 3 have been described in the cervical spine.2-4 Metastatic melanoma to the brain has historically portended a grim prognosis; however, due to the paucity of reported intradural lesions, the clinical course, including surgical findings, is less well known. This video illustrates a case of a 59-year-old man with new left arm pain and numbness found to have cervical intradural extramedullary metastatic melanoma (Video 1). This video also demonstrates surgical principles and techniques for removal of a rare cervical intradural extramedullary melanoma metastasis using standard cervical laminectomy with intraoperative ultrasound for tumor localization. Considering its rarity, visualizing the intraoperative resection is important for surgeons who may potentially treat such pathology. Patient consented for the procedures and for publication of the video.

Effect of Durotomy versus Myelotomy on Tissue Sparing and Functional Outcome after Spinal Cord Injury.

Various surgical strategies have been developed to alleviate elevated intraspinal pressure (ISP) following acute traumatic spinal cord injury (tSCI). Surgical decompression of either the dural (durotomy) or the dural and pial (myelotomy) lining of the spinal cord has been proposed. However, a direct comparison of these two strategies is lacking. Here, we compare the histological and functional effects of durotomy alone and durotomy plus myelotomy in a rodent model of acute thoracic tSCI. Our results indicate that tSCI causes local tissue edema and significantly elevates ISP (7.4 ± 0.3 mmHg) compared with physiological ISP (1.7 ± 0.4 mmHg; p < 0.001). Both durotomy alone and durotomy plus myelotomy effectively mitigate elevated local ISP (p < 0.001). Histological examination at 10 weeks after tSCI revealed that durotomy plus myelotomy promoted spinal tissue sparing by 13.7% compared with durotomy alone, and by 25.9% compared with tSCI-only (p < 0.0001). Both types of decompression surgeries elicited a significant beneficial impact on gray matter sparing (p < 0.01). Impressively, durotomy plus myelotomy surgery increased preservation of motor neurons by 174.3% compared with tSCI-only (p < 0.05). Durotomy plus myelotomy surgery also significantly promoted recovery of hindlimb locomotor function in an open-field test (p < 0.001). Interestingly, only durotomy alone resulted in favorable recovery of bladder and Ladder Walk performance. Combined, our data suggest that durotomy plus myelotomy following acute tSCI facilitates tissue sparing and recovery of locomotor function. In the future, biomarkers identifying spinal cord injuries that can benefit from either durotomy alone or durotomy plus myelotomy need to be developed.

Surgical Disconnection of a Residual Pediatric Pial Arterio-Venous Fistula Following Partial Embolization: A Case Study.

BACKGROUND: Pial arteriovenous fistulas (AVFs) are rare intracranial vascular lesions consisting of 1 or more feeder arteries connecting directly to a venous system without a nidus, in the subpial space. Because of the high-flow system, they are commonly associated with a large varix. They are thought to represent between 1.6% and 7.3% of all pediatric arteriovenous malformations (AVMs). Morbidity and mortality is high in this condition and surgical or endovascular treatment options are usually considered. There have been limited reports on the clinical features, treatment options, and outcomes of pial AVMs due to its rarity. We present a case study of a pediatric patient in our institution and her clinical course, focusing on her presenting clinical features and management. CASE DESCRIPTION: A 1-year-old girl presents with progressively prominent and dilated facial veins and no other features suggestive of pial AVF. She was diagnosed with pial AVF with two feeder arteries and a large varix on imaging. Embolization was undertaken 3 times before successful surgical disconnection was done. Genetic testing for associated syndromes were all negative. CONCLUSIONS: Prominence of facial veins could be 1 of the more uncommon presenting features of pial AVFs. Genetic testing should always be considered in the pediatric population diagnosed with AVFs because of their association to various syndromes. Despite endovascular embolization being considered the less invasive choice, decision on mode of treatment should be a multifactorial decision.

Clinical outcomes of epidural and intradural decompression for treatment of degenerative cervical myelopathy.

OBJECTIVE: This study was performed to examine the clinical outcomes of epidural and intradural decompression for degenerative cervical myelopathy. METHODS: The data for 13 patients who underwent epidural and intradural decompression for treatment of degenerative cervical myelopathy (study group) and 20 patients who underwent only cervical laminoplasty, fusion, and epidural decompression (historical control group) were retrospectively reviewed. The preoperative and postoperative neurological status was evaluated using the Japanese Orthopaedic Association (JOA) score. RESULTS: All patients' neurological symptoms were significantly improved at the final follow-up. In the study group, the patients' mean preoperative JOA score was 8.07 ± 1.80, and the final score improved by 70.88% ± 21.18%. The blood loss and operation time were significantly greater in the study group than control group. The recovery time was shorter in the study group than control group. The improvement rate was not significantly different between the two groups. CONCLUSIONS: A pia mater incision with separation of the arachnoid adhesion can significantly improve the cerebrospinal fluid flow and spinal blood flow in degenerative cervical myelopathy. Arachnoid adhesion can lead to intradural spinal scar compression. The surgical intervention described herein can achieve satisfactory neurological outcomes and shorten the recovery time.

The surgical treatment of Landau-Kleffner syndrome.

The medical management of Landau-Kleffner syndrome is usually effective for seizure control and eventual seizure remission. However, the response for language and behavior is often poor. Surgery, in the form of multiple subpial transections (MSTs) to include Wernicke's area has been suggested as a way forward if electrophysiologic lateralization can be demonstrated. Surgical series in the literature are few and outcome from surgery variable.

Pial synangiosis in patients with moyamoya syndrome and sickle cell anemia: perioperative management and surgical outcome.

OBJECT: Many children with sickle cell anemia (SCA) also have clinical and radiographic findings of an arteriopathy suggestive of moyamoya syndrome. These patients may continue to experience strokes despite optimal medical management. The authors wished to define features of moyamoya syndrome associated with SCA and determine the results of surgical revascularization in these patients at early and late follow-up. METHODS: The authors reviewed the clinical and radiographic records of all patients with moyamoya syndrome and SCA who underwent cerebral revascularization surgery using a standardized surgical procedure-pial synangiosis-from 1985 to 2008. RESULTS: Twelve patients had SCA and moyamoya syndrome. Six patients were female and 6 were male. The average patient age at surgery was 11.3 years (range 3-22 years). All patients presented with ischemic symptoms, 11 (92%) with previous transient ischemic attacks, and 10 (83%) with completed strokes. Eleven patients (92%) had radiographic evidence of previous stroke at presentation. None presented with hemorrhage. Surgical treatment included pial synangiosis in all patients. Complications included 1 perioperative stroke, 1 wound infection, and 1 perioperative pneumonia. The average length of hospital stay was 5.7 days (including a 24-hour preoperative admission for hydration) and average blood loss was 92.5 ml/hemisphere (in a total of 19 hemispheres). Clinical and radiographic follow-up with an average of 49 months (range 9-144 months) demonstrated no worsening in neurological status in any patient. No clinical or radiographic evidence of new infarcts was observed in any patient at late follow-up, despite disease progression in 13 (68%) of 19 hemispheres. CONCLUSIONS: The clinical and radiographic features of moyamoya syndrome associated with SCA appear comparable to primary moyamoya disease. Successful treatment of these patients requires multidisciplinary care involving hematologists, anesthesiologists, and neurosurgeons. Operative treatment of moyamoya syndrome using pial synangiosis appears to be safe and confers long-lasting protection against further stroke in this population, and provides an alternative for failure of optimal medical therapy in patients. This study underscores the potential merit of screening patients with SCA for moyamoya syndrome.