Learning, teaching, and training in microsurgery: A systematic review.

Numerous microsurgical training techniques and materials have been developed to reduce animal use and training costs. This systematic review aimed to catalog the available microsurgery learning methods on non-living material in order to define an educational program. The PubMed database was searched for English and French articles related to the initial learning of microsurgery with inert, non-living, or digital material and containing the keywords "microsurgery", "non-living", "simulation" and "virtual reality". Among the 488 articles found, 82 were included. This work reports the main microsurgery learning supports. They were classified according to the material used: inert material, cadaveric animal tissues, human cadaver model, virtual reality, and digital technologies. The educational program proposes here is a two-step program that uses non-living material (basic and deepening) before progressing to living models. This initial learning phase teaches basic microsurgical skills (precision, tremor management, and magnification). Then, frequent home training sessions help to maintain the acquired skills. Ethical, organizational, and economic constraints limit access to animal models. Therefore, inert models seem to be ideal support for initial microsurgical learning. The multiplicity of models described makes it possible to achieve progressive learning depending on which models are available.

Vein conduits used to enhance arterial microsurgical end-to-end suture repair: A randomized comparative study.

Wrapping microsurgical sutures with a vein conduit is a well-described procedure for microsurgical nerve repair. While this has rarely been described in the context of vascular repair, this technique could increase the permeability of the sutured vessels. As part of a University Diploma in Microsurgery, 9 junior surgeons performed a comparative study of 18 microsurgical repairs on rats with and without vein sleeve. The vessels used were an external jugular vein sleeve on the end-to-end anastomosis of the common carotid artery and comparing it to this same anastomosis without a sleeve. The data analyzed were rat weight, suture time with carotid clamping time, number of stitches used, complications as well as vascular leakage and permeability of the repair at 0 and 5minutes evaluated with a patency test. The average rat body weight was 255g. Mean suture time was 52minutes in group A (sleeved repairs) and 41minutes in group B (standard repairs). The number of stitches placed was 5.1 points on average in group A and 5.6 points in group B. The time to perform the repair and the number of stitches was not statistically different between groups. The patency test was positive in 100% of cases in group A and in 78% of cases in group B. There was a significant difference between the permeability rate of the repairs, with better results in group A (p=0.03). There were two anastomotic leaks after declamping in the sleeve group and five in the standard suture group, thus 2.5 times more leaks in the group without a sleeve (p<0.01). The addition of a vein sleeve around an end-to-end arterial suture repair seems to improve its permeability and therefore its reliability.

Toward the development of 3-dimensional virtual reality video tutorials in the French neurosurgical residency program. Example of the combined petrosal approach in the French College of Neurosurgery.

BACKGROUND: The present study developed 3D video tutorials with commentaries, using virtual reality headsets (VRH). VRHs allow 3D visualization of complex anatomy from the surgeon's point of view. Students can view the surgery repeatedly without missing the essential steps, simultaneously receiving advice from a group of experts in the field. METHODS: A single-center prospective study assessed surgical teaching using 3D video tutorials designed for French neurosurgery and ENT residents participating in the neuro-otology lateral skull-base workshop of the French College of Neurosurgery. At the end of the session, students filled out an evaluation form with 5-point Likert scale to assess the teaching and the positive and negative points of this teaching tool. RESULTS: Twenty-two residents in neurosurgery (n=17, 81.0%) and ENT (n=5) were included. Eighteen felt that the 3D video enhanced their understanding of the surgical approach (81.8%). Fifteen (68.2%) thought the video provided good 3D visualization of anatomical structures and 20 that it enabled better understanding of anatomical relationships (90.9%). Most students had positive feelings about ease of use and their experience of the 3D video tutorial (n=14, 63.6%). Twenty (90.9%) enjoyed using the video. Twelve (54.5%) considered that the cadaver dissection workshop was more instructive. CONCLUSIONS: 3D video via a virtual reality headset is an innovative teaching tool, approved by the students themselves. A future study should evaluate its long-term contribution, so as to determine its role in specialized neurosurgery and ENT diploma courses.

Long term surgical results of 154 petroclival meningiomas: A retrospective multicenter study.

BACKGROUND: Outcomes of petroclival meningiomas (PCM) (morbidity, permanent cranial nerves deficit, tumor removal and recurrence) are inconsistent in the literature, making it a challenge to predict surgical morbidity. METHODS: A multicenter study of patients with PCMs larger than 2.5cm between 1984 and 2017 was conducted. The authors retrospectively reviewed the patients' medical records, imaging studies and pathology reports to analyze presentation, surgical approach, neurological outcomes, complications, recurrence rates and predictive factors. RESULTS: There were 154 patients. The follow-up was 76.8 months on average (range 8-380 months). Gross total resection (GTR) was achieved in 40 (26.0%) patients, subtotal resection (STR) in 101 (65.6%), and partial resection in 13 (8.3%). Six (2.6%) perioperative deaths occurred. The 5-year, 10-year and 15-year progression-free survival (PFS) of GTR and STR with radiation therapy (RT) was similar (100%, 90% and 75%). PFS of STR without adjuvant radiation was associated with progression in 71%, 51% and 31%, respectively. Anterior petrosectomy and combined petrosectomy were associated with higher postoperative CN V and CN VI deficits compared to the retrosigmoid approach. The latter had a significantly higher risk of CN VII, CN VIII and LCN deficit. Temporal lobe dysfunction (seizure and aphasia) were significantly associated with the anterior petrosectomy approach. CONCLUSIONS: Our study shows that optimal subtotal resection of PCMs associated with postoperative RT or stereotactic radiosurgery results in long-term tumor control to equivalent radical surgery. Case selection and appropriate intraoperative judgement are required to reduce the morbidity.

Ptosis and vertical diplopia after ligation of ethmoidal arteries.

The treatment of epistaxis is well codified, ligation of the ethmoidal arteries being the last resort. We report the case of a 25-year-old pregnant patient, who has had a ligation of the anterior and posterior ethmoidal arteries after a persistent epistaxis. Postoperatively, she presented a complete ptosis and an impaired eye elevation without any visual acuity disorders, evoking a lesion of the upper branch of the common oculomotor nerve (third cranial nerve). The patient totally recovered after 3 months. Anatomical study shows that the upper branch of the third cranial nerve is lying very close to the optic nerve and cannot be affected by surgery without any associated damage of the optic nerve. Thus, a vascular etiology seems to be the best explanation of the complication experienced by our patient. Ligation of the posterior ethmoidal artery should be done with caution.

Image-guided transoral approach in severe craniovertebral junction malformations at the golden age of endoscopy: Regarding 2 cases.

INTRODUCTION: The image-guided transoral approach (IGTOA) provides a safe exposure to skull base midline lesions and the ventral aspect of the craniovertebral junction (CVJ). The IGTOA has several advantages: the head being placed in the extended position, it decreases the brainstem angulation during surgery; the approach being done through the avascular median pharyngeal raphe, not only lowers the bleeding risk but also provides a direct access to the bony pathology and granulation tissue accessible only via the ventral route. Wide field exposure and maneuverability are necessary to deal with the entire ventral brainstem compression in case of severe CVJ malformation to safely perform partial clivectomy and odontoidectomy. PRESENTATION OF TWO CASES: We illustrate the cases of two patients, 52-year-old and 42-year-old males, who presented with an impressive craniovertebral junction malformation, confirmed on CT and MRI images. They first underwent surgery by IGTOA, later completed by occipitocervical fixation. For the two patients, outcomes were assessed respectively at 4 and 5 years and showed satisfactory results both clinically and radiologically. CONCLUSION: In patients with marked ventral compression, the IGTOA provides direct and guided access to the anterior aspect of the CVJ and effective means for odontoidectomy and clivectomy. This approach is more easily maneuverable compared to the endonasal endoscopic approach. The IGTOA approach is quite a complex technique, requiring multidisciplinary skills, but it should primarily be used in difficult situations. We suggest that endonasal endoscopy is over-utilized. We consider that endoscopy should not be routinely performed and kept only for well-selected cases.

Lower third clivus and foramen magnum intradural tumor removal: The plea for a simple posterolateral approach.

BACKGROUND: Anterior or anterolateral lesions of the lower third clivus and/or foramen magnum require a surgical exposure that provides a clear visualization of both pathological and normal anatomy without retraction of neural or vascular structures. The posterolateral approach permits access to the anterolateral intradural aspect of the brainstem. The aim of this study was to stress that there is no need for vertebral artery transposition, occipital condyle drilling, occipitocervical fixation or trans-oro-pharyngeal access to remove these lesions. METHODS: All five consecutive patients treated surgically for an intradural foramen magnum lesion in the Department of Neurosurgery at Angers University Hospital, between May 2012 and January 2015, were included in this retrospective study. In 4 cases, patients were referred to us for a second opinion after an initial surgical proposal at another institution. For all patients, the data collected were age at diagnosis, clinical signs, and quality of rostral and caudal exposure of the lesion, quality of resection, complications and postoperative neurological deficits. RESULTS: All patients were operated on with a control of the rostrocaudal part of the lesion, without touching the vertebral artery, or the use of occipital condyle drilling. There was no need for occipitocervical fixation. Total resection was achieved in 4 cases, subtotal resection in one. All had watertight dural closure with no dural patch, or postoperative neurological deficits. No recurrence occurred between 6 and 30 months after surgery. CONCLUSION: Based on these results, the posterolateral approach was a simple, effective and safe procedure for anterior and anterolateral intradural lesion of the foramen magnum.

Post-surgical vestibular schwannoma remnant tumors: What to do?

BACKGROUND: Vestibular schwannomas (VS) are benign tumors of the vestibular nerve's myelin sheath. The current trend in VS surgery is to preserve at the facial function, even if it means leaving a small vestibular schwannoma tumor remnant (VSTR) after the surgery. There is no defined therapeutic management VSTR. The aim of this study was to assess the evolution of the VSTR to define the best therapeutic management and identify predictive factors of VSTR progression. METHODS: Among the 256 patients treated surgically for VS in the Department of Neurosurgery at Angers University Hospital, 33 patients with a post-surgical VSTR were included in this retrospective study. For all surgical patients, the data collected were age at diagnosis, the Koos classification, the surgical access, the existence of a type 2 neurofibromatosis (NF2), the TR location and size on control MRI-scans. Patients had a bi-annual follow-up with clinical status and VSTR size assessment with MRI-scan. Survival analyzes were performed to determine the time and rate of VSTR progression, and identify factors of progression. RESULTS: The mean follow-up of the population was 51 months. All VS remnant progression occurred between 38 and 58 months after surgery. In non-NF2 patients with first follow-up MRI-scan three months after surgery, 43% presented a spontaneous regression, 50% a stability and 7% a progression of the VSTR. In the same population with the 1-year MR-scan after surgery as baseline, 25% presented a spontaneous regression, 62.5% a stability and 12.5% a VSTR progression. These data are consistent with the data reported in the literature. The post-operative facial function impairment and an initial remnant ≥ 1.5cm(3) were found to be significant risk factors of VS remnant progression in non-NF2 population in univariate analysis (P=0.048 and 0.031) but not in multivariate analysis. CONCLUSION: In our experience, the best therapeutic management of the post-surgical VSTP in non-NF2 patients with no risk factor of progression is a simple clinical radiological follow-up otherwise complementary radiosurgery should be considered.

CCM3 Mutations Are Associated with Early-Onset Cerebral Hemorrhage and Multiple Meningiomas.

Mutations of CCM3/PDCD10 cause 10-15% of hereditary cerebral cavernous malformations. The phenotypic characterization of CCM3-mutated patients has been hampered by the limited number of patients harboring a mutation in this gene. This is the first report on molecular and clinical features of a large cohort of CCM3 patients. Molecular screening for point mutations and deletions was used to identify 54 CCM3-mutated index patients. Age at referral and clinical onset, type of inaugural events and presence of extra-axial lesions were investigated in these 54 index patients and 22 of their mutated relatives. Mean age at clinical onset was 23.0 ± 16 years. Clinical onset occurred before 10 years in 26% of the patients, and cerebral hemorrhage was the initial presentation in 72% of these patients. Multiple extra-axial, dural-based lesions were detected in 7 unrelated patients. These lesions proved to be meningiomas in 3 patients who underwent neurosurgery and pathological examination. This 'multiple meningiomas' phenotype is not associated with a specific CCM3 mutation. Hence, CCM3 mutations are associated with a high risk of early-onset cerebral hemorrhage and with the presence of multiple meningiomas.

Spontaneous oral extrusion of an acrylic vertebral reconstruction 12 years after a vertebrectomy for a Ewing's sarcoma of the cervical spine: a case report.

INTRODUCTION: Primary Ewing sarcoma of the cervical spine is rare, particularly in children population. The surgical management remains a challenge to associate the best oncological resection and to prevent spinal deformity. The situation is complicated owing to paucity of adapted instrumentation and their possible interactions with the growing bone. CLINICAL PRESENTATION: We described the case of a young 19-year-old woman admitted for an oral extrusion of a bone polymethyl methacrylate (PMMA) allograft 12 years after a C4 circumferential vertebrectomy for primary Ewing's sarcoma. The vertebral anterior reconstruction was slowly repulsed by the growing spine giving way to an autologous bone without kyphosis deformation. CONCLUSION: Bone reconstruction remains a challenge after extensive oncological resection particularly in cervical spine of children. Anterior and posterior instrumentation must be associated. The growing spine is not a good host for PMMA allograft and autograft seems to be preferred for anterior column fusion. In spite of the good oncological results, the authors raise the long-term issue of PMMA for vertebral reconstruction in young patients. With a long follow-up, they showed that posterior rigid fixation might prevent the cervical kyphosis.

A not so solitary fibrous tumor of the liver.

Solitary fibrous tumor (SFT) is a rare neoplasm. Liver parenchyma is a rare location of SFT and, in this case, it usually follows a benign course. We report here the case of a 54-year-old man who presented a large SFT tumor of the right hepatic lobe. The tumor was surgically resected. Local recurrence occurred 6 years later as a 15 cm diameter liver tumor. Histological examination of the resected lesion showed features of an aggressive form of SFT. Two years later, the patient presented with complaints of neck pain and ensuing examinations revealed a tumor of the cranial base. A new surgical resection was performed and histological examination confirmed a metastasis of the SFT. Few weeks later, the patient presented an irreducible psoitis due to an iliac bone metastasis. He died within 1 month.

[Morphological anatomy of the cranial nerves in their cisternal segment (III-XII)]. / Anatomie morphologique des nerfs crâniens dans leur portion cisternale (du III au XII).

One hundred brains (first injected in cerebral arteries and veins with latex neoprene or India ink and studied under optic magnification) illustrate this anatomic chapter concerning the microsurgical anatomy of the cisternal segment, the neurovascular relationships, and the blood supply of the IIIrd to the XIIth cranial nerves.

[Management of bone-invasive en-plaque petrosal meningiomas. Removal using tailored petrosectomy]. / Méningiomes en plaque pétreux invasifs : place de la pétrectomie << à façon >>

BACKGROUND AND PURPOSE: The invasion of bone responsible for hyperostosis is a typical phenomenon associated with en-plaque meningiomas. Although the sphenoid wing and spheno-orbital region are most frequently affected, petrosal involvement is rare and its surgical treatment difficult. Hyperostosis is caused by bone invasion, is responsible for the clinical signs, and prompts the surgeon to use an à la carte drilling that has to be evaluated preoperatively and carried out depending on tumor extension and the treatment goals. METHODS: We report two cases of invasive and evolving en-plaque petrosal meningiomas. Hyperostosis, bony modifications, and intracranial portion of the lesion were responsible for cophosis, facial palsy, trigeminal neuralgia, dysphonia, and laryngeal palsy in one case, and were responsible for hearing loss and facial palsy in the other case. RESULTS: In both cases, the à la carte petrosectomy allowed us to achieve total removal of the lesion. In one case, we used a trans- and infralabyrinthine transjugular approach (to control the extension of the lesion in the jugular foramen, within the sinusojugular axis, and in the internal auditory canal), associated with an anterior petrosectomy (to control the invaded petrous apex, Meckel's cave, and a middle cranial fossa extension). In the other case, we used a retro- and infralabyrinthine transsigmoid transtentorial approach to control the venous axis, the posterior fossa dura, and the tentorium. Total removal of the tumor including bone invasion was achieved in both cases. Neurological deficits improved or remain unchanged. Transient postoperative facial palsy recovered in two months. CONCLUSIONS: An à la carte petrosectomy performed by a surgical team with great expertise in the field of petrous bone anatomy and segmentation should lead to total removal including exposure of the dural tail and intracranial portion of the tumor, while preserving all cranial nerve functions.

An intraventricular clear cell meningioma revealed by an inflammatory syndrome in a male adult: a case report.

Intraventricular meningiomas are infrequent intracranial tumors. Clinical symptoms are mainly due to an increased intracranial pressure or a direct pressure on the surrounding brain structures. Inflammatory syndrome was described in some patients with chordoid meningiomas. Here we report a case of right intraventricular clear cell meningioma in a 50-year-old man who presented with fever, headache, and inflammatory syndrome. Clinical and biological normalization was rapidly obtained after tumor removal. Immunohistochemical examination showed tumor cells and lymphocytes positivity for the pyrogenic cytokine interleukin-6, with a same intensity. To our knowledge, this is the first case described in the literature concerning an adult man with an intraventricular clear cell meningioma associated with a systemic inflammatory syndrome.

Surgical anatomy of the jugular foramen.

The jugular foramen (JF) is a canal that makes communication between the posterior cranial fossa and the upper neck for one third of the cranial nerves and for the main venous channel of the brain. From a lateral view, the JF is protected by multiple layers of muscles and by the outer surface of the petrous bone. Surgical exposure of the JF is usually justified by the removal of benign tumors that grow in this region. In the first part of the present study we describe the surgical anatomy of the JF Then, we detail the relevant points of a stepwise surgical progression of three lateral skull base approaches with a gradual level of exposure and invasiveness. The infralabyrinthine transsigmoid transjugular-high cervical approach is a conservative procedure that associates a retrolabyrinthine approach to a lateral dissection of the upper neck, exposing the sinojugular axis without mobilization of the facial nerve. In the second step, the external auditory canal is transsected and the intrapetrous facial nerve is mobilized, giving more exposure of the carotid canal and middle ear cavity. In the third step, a total petrosectomy is achieved with sacrifice of the cochlea, giving access to the petrous apex and to the whole course of the intrapetrous carotid artery. Using the same dissection of the soft tissues from a lateral trajectory, these three approaches bring solutions to the radical removal of distinct tumor extensions. While the first step preserves the facial nerve and intrapetrous neurootologic structures, the third one offers a wide but more aggressive exposure of the JF and related structures.

[Extensive lower clivus chordomas. Removal using the unilateral transmandibular approach]. / Chordomes extensifs du clivus inférieur. Exérèse par voie transmandibulaire unilatérale.

BACKGROUND AND PURPOSE: Clival chordomas are rare skull-base tumors with local malignant behavior. Their control and removal remain difficult because of their anatomical location and because of their extensions. The goal of the treatment is complete surgical removal in a single stage if possible, with minimal deficits, followed by proton therapy. If the tumor remains extradural for a while, it finally progresses through the dura backwards to reach and displace the brain stem and upper cervical cord. Its anterior extension in the retropharyngeal space offers a logical opportunity and many advantages to use an anterior approach. METHODS: With three consecutive cases, we try to demonstrate that the unilateral transmandibular approach offers a large exposure of the lower clivus, the foramen magnum in its ventral part, the ipsilateral infratemporal fossa and C1 to C3. Surgical complications concern the lower cranial nerves, including the hypoglossal. Serous otitis media is possible in case of opened Eustachian tube. Tracheostomy is needed because of a transient tongue oedema. RESULTS: The unilateral transmandibular approach enabled to anatomical and physiological nasal preservation, large operative field facilitating dural closure and tumor removal, with acceptable cosmetic results and sequellae considering the natural course and prognosis of the tumor. CONCLUSIONS: This approach seems to be very useful to reach and removed extensive lower chordomas.

[The combined petrosal approach. Anatomical principles, surgical technique and indications]. / La pétrectomie combinée Bases. anatomiques, technique chirurgicale et indications.

Management of large petroclival tumors requires the use of extensive surgical approaches that usually jeopardize the intrapetrous neuro-otologic structures. To confirm the interest of the combined petrosal approach in this indication, we describe the relevant anatomy and the surgical steps of this procedure. After making a periauricular skin incision and muscle elevation, an occipitotemporal bone flap is shaped. Then a retrolabyrinthine exposure is undertaken, with optimal skeletonization of the semicircular canals. Around the internal auditory canal, the retromeatal area and the petrous apex are resected. The retrosigmoid dura is opened followed by the incision of the subtemporal and posterior fossa dura along the superior petrosal sinus. The sinus is coagulated and divided. The tentorium is sectioned transversally toward its free edge behind the porus of the trochlear nerve. The combined petrosal approach is able to provide a wide multidirectional corridor toward the ventral surface of the pons, the basilary trunk and the ipislateral cranial nerves from the oculomotor to the lower cranial nerves. This study confirms that despite a significant extra time needed for proper achievement, the combined petrosal approach is a valuable conservative approach when the petroclival area, ventral brain stem and basilary trunk are targeted. This approach should be included in the panel of the transpetrous routes available by expert skull base teams.

Vascular microanatomy of the pontomedullary junction, posterior inferior cerebellar arteries, and the lateral spinal arteries.

SUMMARY: This study of 25 brains at the pontomedullary junction defined the different possible origins of the perforating arteries and lateral spinal arteries in relation to the posterior inferior cerebellar arteries (PICAs). - If the PICA emerges from the common trunk of the AICA-PICA coming from the basilar artery, it never gives perforating arteries or a lateral spinal artery on the lateral surface of the brain stem but supplies blood to a part of the ipsilateral cerebellar hemisphere. - If the PICA arises extradurally at C1, it never gives perforating arteries for the lateral surface of the brain stem, but it gives pial branches for the posterior surface of the medulla oblongata and is always the origin of the lateral spinal artery. - If the PICA emerges in the intradural vertebral artery, it is the source of the perforating arteries for the lateral surface of the brain stem and of the blood supply of the ipsilateral cerebellum.

Surgical anatomy of the petrous apex and petroclival region.

Surgical exposure of the clivus, the ventral or lateral aspect of the brain stem, and all the intradural structures of the petroclival area remains difficult because of the presence of the petrous apex and peripetrous complex. However, a lateral skull base approach to the petroclival area is the most suitable approach if the lesion to be resected lies medial to the fifth nerve, in front of the acousticofacial bundles, extending towards the midline. The purpose of this study is to review the topographic anatomy of the petrous apex and peripetrous structures, with emphasis on the relationships important to the lateral approaches to the petroclival area. Such anatomical knowledge allows us to study the surgical technique, exposure, and pitfalls of the main lateral transpetrosal skull base approaches used to reach the petroclival area.