Surgical management of large lower cranial nerves schwannomas: long term results of a less aggressive resection strategy.

In an effort to reduce the high morbidity and life-threatening complications after radical resection in large schwannoma surgery, alternative strategies of nontotal resections have emerged. To evaluate the long term clinical and oncological outcome after lower cranial nerves (LCN) schwannoma surgery operated on with a cranial nerve-sparing technique. Single center retrospective cohort study of 8 consecutive patients harboring LCN schwannomas operated on between March 2005 and October 2021. The mean LCN schwannoma diameter was 33 mm (range 26-51). Seven patients (87,5%) underwent a modified retrosigmoid approach. Three patients underwent gross total resection (37,5%), 3 had received neartotal resection (mean tumor residue 0,25 cc) and subtotal resection in 2 patients who presented with an extracranial extension of the tumor (mean tumor residue 2,44 cc). Both patients had received upfront additional GKRS. The three patients who presented with preoperative CN IX & X injuries recovered within 6 months after surgery. All of the five patients freed from any preoperative CNs IX & X symptoms experienced transient (80%) or definitive (one patient) disturbances after surgery. They all improved within 6 months but one who required long term gastrostomy feeding tube. This patient harbored a schwannoma originating from the glossopharyngeal nerve, which could not be anatomically preserved during surgery. Tumor control was achieved in 100% of cases with a mean follow-up of 91 months. LCN schwannomas could be surgically removed through a less aggressive non-radical resection strategy with acceptable functional results and excellent tumor control.

Predictive factors of the postoperative proptosis recovery in surgery of spheno-orbital meningiomas.

OBJECTIVE: This study aimed to identify factors affecting proptosis recovery in spheno-orbital meningioma (SOM) surgery and assess functional and oncological outcomes. METHODS: Data from 32 consecutive SOM surgery cases (2002-2021) were analyzed. Clinical, radiological, operative, and oncological parameters were examined. Proptosis was assessed using the exophthalmos index (EI) on MRI or CT scans. Statistical analyses were performed to identify predictive factors for proptosis recovery. RESULTS: Proptosis improved in 75% of patients post-surgery (EI decreased from 1.28 ± 0.16 to 1.20 ± 0.13, p = 0.048). Patients with stable or worsened EI had higher body mass index (28.5 ± 7.9 vs. 24.1 ± 4.7, p = 0.18), Simpson grade (IV 75% vs. 65%, p = 0.24), and middle sphenoid wing epicenter involvement (63% vs. 38%, p = 0.12), but no significant factors were associated with unfavorable exophthalmos outcomes. The improvement group had higher en plaque morphology, infratemporal fossa invasion, and radiation treatment for cavernous sinus residual tumor (88% vs. 75%, p = 0.25; 51% vs. 25%, p = 0.42; 41% vs. 25%, p = 0.42, respectively), but without statistical significance. Visual acuity remained stable in 78%, improved in 13%, and worsened in 9% during follow-up. Surgery had a positive impact on preoperative oculomotor nerve dysfunction in 3 of 4 patients (75%). Postoperative oculomotor nerve dysfunction was observed in 25%, of which 75% fully recovered. This occurrence was significantly associated with irradiation of an orbital tumor residue (p = 0.04). New postoperative trigeminal hypoesthesia was observed in 47%, of which 73% recovered. All SOMs were classified as WHO grade 1, and complementary treatments achieved oncological control, requiring gamma-knife radiosurgery in 53% and standard radiotherapy in 6%. CONCLUSIONS: Surgery effectively improves proptosis in SOM, though complete resolution is rare. The absence of predictive factors suggests multifactorial causes, including body mass index and tumor resection grade. Postoperative oculomotor nerve dysfunction and trigeminal hypoesthesia are common but often recover. Gamma-knife radiosurgery maintains long-term oncological control for evolving tumor residue.

The trans-sylvian trans-petrosal "half & half" approach-a how I do it.

BACKGROUND: Petroclival meningiomas are one of the most challenging tumors to be operated in the realm of neurosurgery. Many approaches have been developed over the years. METHOD: The authors describe the Half & Half (H&H) approach whose main indication is petroclival meningiomas with suprasellar extension. The part of the tumor located above CN III and in the retrochiasmatic space is addressed through a trans-sylvian, while the petroclival portion is through an extradural anterior petrosectomy approach. The wide surgical corridor given by this approach allows extensive tumor resection while avoiding the risk associated with the manipulation of intracavernous neurovascular structures. CONCLUSION: The H&H approach is an effective strategy to maximize the safe resection of petroclival meningiomas.

Assessing Tumor Volume for Sporadic Vestibular Schwannomas: A Comparison of Methods of Volumetry.

INTRODUCTION: The size of vestibular schwannomas (VS) is a major factor guiding the initial decision of treatment and the definition of tumor control or failure. Accurate measurement and standardized definition are mandatory; yet no standard exist. Various approximation methods using linear measures or segmental volumetry have been reported. We reviewed different methods of volumetry and evaluated their correlation and agreement using our own historical cohort. METHODS: We selected patients treated for sporadic VS by Gammaknife radiosurgery (GKRS) in our department. Using the stereotactic 3D T1 enhancing MRI on the day of GKRS, 4 methods of volumetry using linear measurements (5-axis, 3-axis, 3-axis-averaged, and 1-axis) and segmental volumetry were compared to each other. The degree of correlation was evaluated using an intraclass correlation test (ICC 3,1). The agreement between the different methods was evaluated using Bland-Altman diagrams. RESULTS: A total of 2,188 patients were included. We observed an excellent ICC between 5-axis volumetry (0.98), 3-axis volumetry (0.96), and 3-axis-averaged volumetry (0.96) and segmental volumetry, respectively, irrespective of the Koos grade or Ohata classification. The ICC for 1-axis volumetry was lower (0.72) and varied depending on the Koos and Ohata subgroups. None of these methods were substitutable. CONCLUSION: Although segmental volumetry is deemed the most accurate method, it takes more effort and requires sophisticated computation systems compared to methods of volumetry using linear measurements. 5-axis volumetry affords the best adequacy with segmental volumetry among all methods under assessment, irrespective of the shape of the tumor. 1-axis volumetry should not be used.

Extradural disconnection of the cavernous sinus with preservation of the internal carotid artery: indication and technique.

BACKGROUND: Extradural disconnection of the cavernous sinus (CS) with preservation of the internal carotid artery (ICA) is indicated for aggressive and recurrent tumors, in patients presenting loss of oculomotor function and non-functional circle of Willis. METHOD: Extradural resection of the anterior clinoid process disconnects the CS anteriorly. The ICA is dissected in the foramen lacerum via extradural subtemporal approach. The intracavernous tumor is split and removed following the ICA. Bleeding control of the inferior and superior petrosal and intercavernous sinuses completes posterior CS disconnection. CONCLUSION: This technique can be proposed for recurrent CS tumors and need of ICA preservation.

Risk factors for the development of degenerative cervical myelopathy: a review of the literature.

Degenerative cervical myelopathy (DCM) encompasses various pathological conditions causing spinal cord (SC) impairment, including spondylosis (multiple level degeneration), degenerative disc disease (DDD), ossification of the posterior longitudinal ligament (OPLL), and ossification of the ligamentum flavum (OLF). It is considered the most common cause of SC dysfunction among the adult population. The degenerative phenomena of DDD, spondylosis, OPLL and OLF, is likely due to both inter-related and distinct factors. Age, cervical alignment, and range of motion, as well as congenital factors such as cervical cord-canal mismatch due to congenital stenosis, Klippel-Feil, Ehler-Danlos, and Down syndromes have been previously reported as potential factors of risk for DCM. The correlation between some comorbidities, such as rheumatoid arthritis and movement disorders (Parkinson disease and cervical dystonia) and DCM, has also been reported; however, the literature remains scare. Other patient-specific factors including smoking, participation in contact sports, regular heavy load carrying on the head, and occupation (e.g. astronauts) have also been suggested as potential risk of myelopathy development. Most of the identified DCM risk factors remain poorly studied however. Further researches will be necessary to strengthen the current knowledge on the subject, especially concerning physical labors in order to identify patients at risk and to develop an effective treatment strategy for preventing this increasing prevalent disorder.

Does general comorbidity impact the postoperative outcomes after surgery for large and giant petroclival meningiomas?

We assessed the role of the general condition of the patient in addition to usual anatomical reasoning to improve the prediction of personalized surgical risk for patients harboring a large and giant petroclival meningiomas. Single-center, retrospective observational study including adult patients surgically treated for a large and giant petroclival meningioma between January 2002 and October 2019 in a French tertiary neurosurgical skull-base center by one Neurosurgeon. Inclusion criteria were as follows: (1) histopathologically proven meningioma; (2) larger than 3 cm in diameter; (3) located within the upper two-thirds of the clivus, the inferior petrosal sinus, or the petrous apex around the trigeminal incisura, medial to the trigeminal nerve. Clinical and radiological characteristics were gathered preoperatively including ASA score, the modified frailty index, and the Charlson comorbidity index. Post-operative severe neurological and non-neurological complications were collected. A total of 102 patients harboring a large and giant petroclival meningioma were included. The rate of postoperative death was 3.0% related to a congestive heart failure (n = 1), a surgical site hematoma (n = 1), and an ischemic stroke (n = 1). A severe neurological impairment was found in 12.8% and a severe non-neurological morbidity was found in 4.0%. The overall rate of severe morbidity and mortality was 15.7% after large and giant petroclival meningioma surgery. The presence of brainstem peri-tumoral edema (adjusted OR, 4.83 [95% CI 1.84-7.52], p = 0.028) was independently associated with a history of postoperative severe neurological morbidity. Male gender (adjusted OR, 7.42 [95% CI 1.05-49.77], p = 0.044), major cardiovascular morbidity (adjusted OR, 9.5 [95% CI 1.05-86.72], p = 0.045), and an ASA score ≥ 2 (adjusted OR, 11.09 [95% CI 1.46-92.98], p = 0.038) were independently associated with a history of postoperative severe non-neurological morbidity. A modified frailty index ≥ 1 (adjusted OR, 3.13 [95% CI 1.07-9.93], p = 0.047) and a low neurosurgical experience (adjusted OR, 5.38 [95% CI 1.38-20.97], p = 0.007) were independently associated with a history of postoperative overall morbidity and mortality. Pre-operative cranial nerve deficits (adjusted OR, 4.77 [95% CI 1.02-23.31], p = 0.024) and gross total resection (adjusted OR, 10.72 [95% CI 1.72-66.90], p = 0.022) were independently associated with postoperative new cranial nerve deficits. This study suggests to add scores assessing the patient general condition in daily practice to improve the selection of patients eligible for surgery. Collaborative international multicenter studies will be necessary to confirm these results and allow their implementation in clinical routine.

Predictors of visual function after resection of skull base meningiomas with extradural anterior clinoidectomy.

Skull base meningiomas threatening the optic nerves may require performing an extradural anterior clinoidectomy (EAC) to optimally decompress the optic pathways. The present study evaluated the functional results and morbidity after surgical resection of skull base meningiomas including EAC, focusing on visual acuity (VA) and oculomotricity. Eighty-seven consecutive patients harboring skull base meningiomas who underwent surgical resection that included an EAC between 2003 and 2020 were retrospectively analyzed (86% women, median age 53 years). Decreased visual acuity (DVA) was graded as functional (VA ≥ 5/10) and nonfunctional (VA < 5/10). Statistical analyses were performed on VA and oculomotor nerve (OcN) dysfunction. Ninety surgical procedures were performed. Meningiomas were located at the anterior clinoid process (39%), cavernous sinus (31%), and spheno-orbital (30%) levels. Patients with a preoperative functional vision (normal or functional DVA) had a 90.9% (IC95% = [84.0; 97.8]) probability of preserving it at 6 months and an 84.8% (IC95% = [76.2; 93.5]) probability at last follow-up. Patients with preoperative nonfunctional vision (nonfunctional DVA or blindness) had a 19.0% (IC95% = [2.3; 35.8]) probability of recovery of functional vision at 6 months and a 23.8% (IC95% = [5.6; 42.0]) probability at last follow-up. Preoperative DVA was significantly associated with early postoperative DVA in univariate analyses (p = 0.04). Concerning the OcN, 65% of the patients experienced a postoperative dysfunction, and 78% of those cases recovered. Our study confirms EAC as a useful technical option for skull base meningiomas threatening the optic nerve, especially relevant for patients with preoperative functional vision, and supports early surgical management for these meningiomas.

Is salvage surgery for large vestibular schwannomas after failed gamma knife radiosurgery more challenging?

In order to verify whether a previous gamma knife surgery (GKS) treatment could influence the oncological and functional outcome in large vestibular schwannoma (VS) surgery, we have compared group of patients operated on for large VS after failed GKS to a group of genuine VS that underwent the same functional nerve-sparing resection technique regimen in the same period. Single center retrospective cohort study of 23 consecutive GKS failure and 170 genuine VS patients operated on between April 2003 and March 2019. After resection, patients were allocated to a Wait-&-rescan or an upfront GKS policy. At last follow-up examination, the facial nerve function was good (House-Brackmann grades I or II) in 95% of the GKS failure and 84% of the genuine VS patients (p = .25). The median volume of tumor residue was .56 cc in the GKS failure group and .62 cc in the genuine VS group (p = .70). Tumor control was achieved in 91% and 83% of cases with a mean follow-up of 74 and 63 months in the GKS failure and the genuine VS populations, respectively. The 1-, 5-, and 7-year progression-free survival were 100%, 95%, and 85% respectively in the GKS failure group and 97%, 80%, and 81% in the genuine VS group (p = .27). Despite significant modifications of the microsurgical environment associated to salvage surgery after GKS failure, a functional nerve-sparing resection is an effective strategy to optimize the results on facial nerve function, with similar long-term tumor control to those observed in the genuine VS population.

Long-term surgical oncological and functional outcome of large petroclival and cerebellopontine angle epidermoid cysts: a multicenter study.

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.

Ipsilateral vs controlateral approach in tuberculum sellae meningiomas surgery: a retrospective comparative study.

Most of tuberculum sellae meningiomas (TSM) show asymmetric growth. They are usually resected through ipsilateral approaches. The access of the inferior-medial side of the ipsilateral optic nerve might be challenging, which result in increased manipulation of the compromised optic nerve. The contralateral approach has been described to avoid these technical difficulties. Assessing the long-term visual and olfactory outcome, as well as recurrence rate in patients operated for TSM through ipsilateral or contralateral approaches. Single center retrospective cohort study about 94 patients operated on between March 2000 and April 2018. Seventy percent of the preoperative visual acuity loss totally resolved (44%) or showed varying degrees of improvement (26%) after surgery. Seventy-two percent of the preoperative visual field defects evolved favorably (44% recovery, 28% improvement). Eight patients showed aggravated visual disturbances (9%). A contralateral approach seemed to be predictive of visual field defects improvement after surgery (OR = 0.4), with borderline significant results (p = .08). There was a higher rate of postoperative olfactory nerve impairment after a contralateral approach (37% vs 17%, p = .03). Total removal of the tumor fragment entering the optic canal was accomplished in 96% in the contralateral vs 75% in the ipsilateral group (p = .04). The 2-, 5-, and 7-year tumor progression-free survival were 100% in the Simpson grade 2 group, and 85% (n = 17), 74% (n = 11), and 67% (n = 5) in the Simpson grade 4 group, respectively (p = .00). Resection of tuberculum sellae meningiomas through a contralateral approach seems to provide better visual outcome and tumor control at the cost of increased olfactory nerve disorders.

Does NF2 status impact the results of combined surgery and adjunctive Gamma Knife surgery for large vestibular schwannomas?

In order to verify whether neurofibromatosis type 2 (NF2) could influence the oncological and functional outcome in large vestibular schwannoma (VS) surgery, we compared a group of NF2 patients operated with a facial nerve-sparing technique to a group of sporadic VSs of similar volume that underwent the same treatment regimen in the same period. Single-center retrospective cohort study about 12 consecutive NF2 and 69 non-NF2 patients operated on for large VS between September 2006 and November 2016. After resection, patients were allocated to an upfront Gamma Knife surgery policy of the tumor residue. At last follow-up examination, the facial nerve function was good (House-Brackmann grades I or II) in 92% of the NF2 and 83% of the non-NF2 patients (p = .90). The median volume of tumor residue was .92 cc in the NF2 group and .54 cc in the non-NF2 group (p = .14). Tumor control was achieved in 83% and 81% of cases in the NF2 and the non-NF2 populations, respectively, with a mean follow-up of 73 months in both groups. The 1-, 5-, and 7-year progression-free survival were 92%, 83%, and 83% respectively in the NF2 group, and 99%, 83%, and 80% in the non-NF2 group (p = .96). Our analysis of 12 NF2 and 69 non-NF2 patients operated on by the same surgical team with the same treatment regimen did not show any functional or tumor control difference between those groups.

Functional sparing surgery policy for giant vestibular schwannomas.

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.

The modified retrosigmoid approach: a how I do it.

BACKGROUND: The traditional retrosigmoid (RS) approach provides limited exposure of the inferior compartment of the CPA, while radical skull base approaches are demanding and associated with significant morbidity. METHODS: This study outlines the relevant surgical anatomy and the different surgical steps of a modified retrosigmoid (MRS) approach. RESULTS: The MRS provides enhanced exposure of the CPA and deep vascular structures resulting from a modified RS craniotomy and limited exposure of the sigmoid sinus. CONCLUSION: In selected posterior fossa lesions, this cisternal approach is a straightforward corridor that can be routinely performed as a safe alternative to radical cranial base approaches.

Robot-assisted multi-level anterior lumbar interbody fusion: an anatomical study.

BACKGROUND: Minimally invasive surgical approaches still provide limited exposure. Access to the L2-L5 intervertebral discs during a single procedure is challenging and often requires repositioning of the patient and adopting an alternative approach. OBJECTIVES: Investigate the windows to the L2-L5 intervertebral discs to assess the dimensions of the interbody implants suitable for the procedure and evaluate the feasibility of multi-level lumbar intervertebral disc surgery in robot-assisted surgery (RAS) METHODS: Sixteen fresh-frozen cadaveric specimens underwent a retroperitoneal approach to access the L2-L5 intervertebral discs. The L2-L3 to L4-L5 windows were defined as the distance between the left lateral border of the aorta (or nearest common iliac vessel) and the medial border of the psoas, measured in a static state and after gentle medial retraction of the vascular structures. Two living porcine specimens and one cadaveric specimen underwent da Vinci robot-assisted transperitoneal approach to expose the L2-L3 to L4-L5 intervertebral discs and perform multi-level discectomy and interbody implant placement. RESULTS: The L2-L3 to L4-L5 intervertebral disc windows significantly increased from a static to a retracted state (p < 0.05). The mean L2-L3, L3-L4, and L4-L5 windows measured respectively 20.1, 21.6, and 19.6 mm in the static state, and 27.2, 30.9, and 30.3 mm after gentle vascular retraction. The intervertebral windows from L2-L3 to L4-L5 were successfully exposed through an anterior transperitoneal approach with the da Vinci robot on the cadaveric and living porcine specimens, and interbody implants were inserted. CONCLUSION: RAS appears to be feasible for a mini-invasive multi-level lumbar intervertebral disc surgery. The RAS procedure, longer and more expensive than conventional MIS approaches, should be reserved for elective patients.

The medial orbito-frontal approach for orbital tumors: a How I Do It.

BACKGROUND: A variety of lesions can affect the orbit. Surgical approaches must be available to provide 360 degrees of access. For tumors occupying the superomedial intraconal quadrant, there is a rationale to selecting the medial orbito-frontal approach. METHODS: This article outlines the relevant surgical anatomy and the different surgical steps of this approach. RESULTS: The medial orbito-frontal approach offers a full exposure of the superomedial intraconal quadrant and avoids crossing the plane of the optic nerve. CONCLUSION: In selected intraconal tumor cases, this transcranial epidural intraorbital approach is a straightforward corridor through reliable landmarks that can be routinely performed.

How I do it: the combined petrosectomy.

BACKGROUND: Petroclival and ventral brain stem tumors require a complex approach. METHOD: The combined petrosectomy is an epidural transtentorial-transpetrosal otoneurosurgical approach to achieve a retrolabyrinthine presigmoidal approach and an anterior petrosectomy in one single procedure. The different steps of this approach are described and illustrated by figures and a video. The indications and limitations of the technique are presented. CONCLUSION: The combined petrosectomy offers multiple corridors to the petroclival region and ventral brainstem while preserving the intrapetrous neurotological structures. Meticulous stepwise bony resection optimizing the dural opening and preservation of veins contributes to reducing the risk inherent to this technique.

The epidural approach to the Meckel's cave: a how I do it.

BACKGROUND: Meckel's cave (MC) is a meningeal cleft lying in the middle fossa laterally to the cavernous sinus. Tumours that develop inside the MC may require a surgical resection. The authors describe the surgical technique of the intracranial epidural approach to the MC. METHODS: Based upon anatomical dissection showing the relevant surgical anatomy, and illustrated by the video of an operated case, the authors detail the surgical procedure. The key point is to shave the floor of the middle fossa and skeletonize the superior orbital fissure, rotundum and ovale foramen in order to delineate the plane of dural elevation and expose the lateral wall of the MC. The rules of exposure and resection of the tumour are then shown. Variations and limitations of the approach are discussed. CONCLUSION: Conducted in a stepwise manner and following relevant landmarks, the epidural anterolateral approach offers a safe and reliable exposure to the diseases that develop within the MC.

Embolization of the middle meningeal artery for the prevention of chronic subdural hematoma recurrence in high-risk patients: a randomized controlled trial-the EMPROTECT study protocol.

BACKGROUND: Middle meningeal artery (MMA) embolization has been proposed as a treatment of chronic subdural hematoma (CSDH). The benefit of the procedure has yet to be demonstrated in a randomized controlled trial. We aim to assess the efficacy of MMA embolization in reducing the risk of CSDH recurrence 6 months after burr-hole surgery compared with standard medical treatment in patients at high risk of postoperative recurrence. METHODS: The EMPROTECT trial is a multicenter open label randomized controlled trial (RCT) involving 12 French centers. Adult patients (≥18 years) operated for CSDH recurrence or for a first episode with a predefined recurrence risk factor are randomized 1:1 to receive either MMA embolization within 7 days of the burr-hole surgery (experimental group) or standard medical care (control group). The number of patients to be included is 342. RESULTS: The primary outcome is the rate of CSDH recurrence at 6 months. Secondary outcomes include the rate of repeated surgery for a homolateral CSDH recurrence during the 6-month follow-up period, the rate of disability and dependency at 1 and 6 months, defined by a modified Rankin Scale (mRS) score ≥4, mortality at 1 and 6 months, total cumulative duration of hospital stay during the 6-month follow-up period, directly or indirectly related to the CSDH and embolization procedure-related complication rates. CONCLUSIONS: The EMPROTECT trial is the first RCT evaluating the benefit of MMA embolization as a surgical adjunct for the prevention of CSDH recurrence. If positive, this trial will have a significant impact on patient care. TRIAL REGISTRATION NUMBER: NCT04372147.