Clinical study of microsurgical treatment of pontine hemorrhage with retrosigmoid approach from the cer-ebellopontine angle / 中国神经精神疾病杂志

Objective To explore the efficacy of the retrosigmoid sinus approach through the cerebellopontine angle in the treatment of pontine hemorrhage.Methods A retrospective analysis was performed on 108 patients with pontine hemorrhage in Kaifeng Central Hospital from January 2016 to June 2022.They were divided into two groups according to the treatment methods,the conservative treatment group and the craniotomy treatment group(transcerebellopontine angle sigmoid sinus posterior approach).There were 94 cases in the conservative treatment group and 14 cases in the surgical treatment group.First analysis was conducted to examined whether there are differences in gender,age,Glasgow Coma Score(GCS)on admission,bleeding volume,comorbidities and complications between the two groups.Additional analysis was performed to analyze modified Rankin(modified Rankin scale,mRS)score and mortality rate after three month follow-up in case there was no significant difference at first analysis.Results There were no statistical differences in gender,age,Glasgow Coma Score(GCS)on admission,bleeding volume,comorbidities and complications between the two groups.After 3 months of follow-up,49 patients died in the conservative treatment group and 3 patients in the craniotomy treatment group.The mortality rates of the two groups were 52.1％and 21.4％respectively(χ2=4.600,P<0.05)).There was a statistical difference in the mortality rate between the two groups,and the mortality rate of the craniotomy treatment group was significantly lower than that of the conservative group.The modified Rankin score was 4(3,5)in the conservative treatment group and 3(2,3)in the craniotomy group(Z=-2.994,P<0.01).The modified Rankin score in the craniotomy group was lower than that in conservative treatment group after 3 months.Conclusion Microsurgery through the cerebellopontine angle retrosigmoid sinus approach to treat pontine hemorrhage can significantly reduce patient mortality and improve prognosis and is an effective surgical treatment method.

A minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal: a step by step description / Abordagem retrosigmoide minimamente invasiva assistida por endoscopia para remoção de cistos aracnóides no conduto auditivo interno: descrição passo a passo

Abstract Introduction: Arachnoid cyst in the internal auditory canal is a quite rare pathology but due to its compressive action on the nerves in this district should be surgically removed. Several surgical techniques have been proposed but no surgeons have used the minimally assisted endoscope retrosigmoid approach for its removal. Objective: To investigate the feasibility of using a minimally invasive endoscope assisted retro-sigmoid approach for surgical removal of arachnoid cysts in the internal auditory canal. Methods: Minimally invasive endoscope assisted retrosigmoid approach allows to access to the internal auditory canal through a minimally invasive retrosigmoid approach that combines the use of a microscope and an endoscope. It is performed in six steps: soft tissue step, bone step, dura step, cerebellopontine angle step (performed using an endoscope and a microscope), microscope-endoscope assisted arachnoid cysts removal and closure. We tested minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal on two human cadaveric heads (specimens) of subjects affected from audio-vestibular disorders and with arachnoid cysts in the internal auditory canal confirmed by magnetic resonance imaging. Results: The mass was completely and successfully removed from the two specimens with no damage to the nerves and/or vessels in the surgical area. Conclusion: The results of our study are encouraging and support the feasibility of using minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal. While further clinical in-vivo studies are needed to confirm the accuracy and safety of using the minimally invasive endoscope assisted retrosigmoid approach for this specific surgery, our group has successfully used the minimally invasive endoscope assisted retrosigmoid approach in the treatment of microvascular compressive syndrome, schwannoma removal and vestibular nerve resection.

Resumo Introdução: O cisto aracnóide no conduto auditivo interno é uma doença bastante rara, mas, devido à sua ação compressiva sobre os nervos deste local, ele deve ser removido cirurgicamente. Várias técnicas cirúrgicas foram propostas, mas ninguém utilizou a abordagem retrosigmoide minimamente invasiva assistida por endoscopia para a sua remoção. Objetivo: Investigar a viabilidade do uso da abordagem retrosigmoide minimamente invasiva assistida por endoscopia para remoção cirúrgica de cistos aracnóides no conduto auditivo interno. Método: A abordagem retrosigmoide minimamente invasiva assistida por endoscopia permite o acesso ao conduto auditivo interno através de uma abordagem retrosigmóide minimamente invasiva que combina o uso de um microscópio e um endoscópio. É realizada em seis etapas: do tecido mole, óssea, dura-máter, do ângulo pontocerebelar (realizado com um endoscópio e um microscópio), remoção e fechamento assistidos por endoscópio-microscópico. Testamos a abordagem retrosigmoide minimamente invasiva assistida por endoscopia para remoção de cistos aracnóides no conduto auditivo interno em duas cabeças de cadáveres humanos (espécimes) de indivíduos afetados por distúrbios auditivos-vestibulares e com cistos aracnóides no conduto auditivo interno confirmado por imagem de ressonância magnética. Resultados: A lesão foi removida completamente e com sucesso nos dois espécimes sem dano aos nervos e/ou vasos na área cirúrgica. Conclusão: Os resultados do nosso estudo são encorajadores e apoiam a viabilidade do uso da abordagem retrosigmoide minimamente invasiva assistida por endoscopia para remoção de cistos aracnóides no conduto auditivo interno. Embora mais estudos clínicos in vivo sejam necessários para confirmar a precisão e a segurança do uso da abordagem retrosigmoide minimamente invasiva assistida por endoscopia para essa cirurgia específica, nosso grupo utilizou com sucesso a abordagem retrosigmoide minimamente invasiva assistida por endoscopia no tratamento da síndrome compressiva microvascular, remoção de schwannoma e ressecção do nervo vestibular.

Medical image software in anatomical measurements and precision craniotomy via suboccipital retrosigmoid sinus approach / 中华神经医学杂志

Objective:To evaluate the application of a medical image software (RadiAnt) in anatomical measurements and precision craniotomy via suboccipital retrosigmoid sinus approach.Methods:A total of 43 inpatients who underwent craniocerebral CT venography (CTV) in our hospital from June 2020 to June 2021 were selected for the study; the CTV data of 35 patients was used to measure the spatial relations between transverse sigmoid sinus junction (TSSJ) and asterion; the preoperative planning in suboccipital retrosigmoid sinus craniotomy with the software was performed in the left 8 patients. Craniotomy time (subjected to exposure of venous sinus margin), venous sinus injury and incidence of complications within 2 weeks of craniotomy in these 8 patients were recorded.Results:(1) Anatomic measurement: for the left side, TSSJ was located at (0.89±0.33) cm lateral and (0.63±0.46) cm inferior to the asterion, and their direct distance was (1.15±0.42) cm; TSSJ was located at (0.76±0.49) cm interior and (1.97±0.52) cm superior to the starting point of the mastoid notch, and their direct distance was (2.18±0.49) cm; about 29% asterion were located superior to the transverse sinus, 37% were located on the surface of the transverse sinus, and 34% were located inferior to the transverse sinus. For the right side, TSSJ was located at (0.88±0.39) cm lateral and (0.64±0.43) cm inferior to the asterion, and their direct distance was (1.12±0.54) cm; TSSJ was located at (0.74±0.40) cm interior and (1.93±0.45) cm superior to the starting point of the mastoid notch, and their direct distance was (2.16±0.43) cm; about 26% asterion were located superior to the transverse sinus, 40% were located on the surface of the transverse sinus, and 34% were located inferior to the transverse sinus. (2) Preoperative planning and surgeries: in these 8 patients, the key-hole was located at (0.96±0.49) cm lateral and (0.53±0.18) cm inferior to the asterion, and (0.46±0.35) cm interior and (1.76±0.47) superior to the starting point of mastoid notch. The interior of sigmoid sinus was located (0.13±0.51) cm interior and (0.21±0.46) cm superior to the starting point of mastoid notch. The inferior of the transverse sinus was located (2.17±0.45) cm interior and (0.53±0.35) cm inferior to the asterion. An accurate localization of the real position of TSSJ, inferior of transverse sinus and interior of sigmoid sinus was performed in all 8 surgical patients. The distance between the margin of the bone window and the interior of sigmoid sinus was (3.5±1.0) mm, and the craniotomy time was (25.7±4.1) min; no sinus injury was noted. Post-operative CT showed good reposition of the bone flaps and less bone defect. There was no cerebrospinal fluid leakage or subcutaneous effusion during the 2 weeks of follow-up.Conclusion:Anatomical measurements and preoperative planning can be quickly finished with low cost with Radiant ?, which provides an efficient and safe method for accurate craniotomy via suboccipital retrosigmoid approach.

Abordaje retrosigmoideo para clipaje de aneurisma distal de la AICA / Retrosigmoid approach for clipping a distal aneurysm of the AICA

Introducción: Los aneurismas cerebrales de la circulación posterior, representan solo del 8 al 10 % del total de los aneurismas cerebrales, y de estos los de la arteria cerebelosa anteroinferior (AICA) son muy poco frecuentes, por lo que no hay algoritmo de manejo para estas lesiones, se requieren conocimientos anatómicos de vascular y de base de cráneo para el tratamiento de estos, hablando del abordaje quirúrgico, podemos mencionar, el extremo lateral, retrosigmoideo, orbitozigomatico y presigmoideo, que depende del tamaño y localización del aneurisma, ya sea distal o proximal. Presentamos este caso, que tratamos mediante un abordaje retrosigmoideo convencional, el cual nos ofreció un corredor quirúrgico suficiente, sin necesidad de un abordaje mas amplio, en este caso fue un aneurisma distal de la AICA, localizado en el segmento meatal, que se encontró en el complejo neurovascular medio del ángulo pontocerebeloso, muy próximo a los nervios craneales V, VII y VIII. Objetivos: Demostrar que los aneurismas distales de la AICA se pueden manejar mediante un abordaje retrosigmodeo convencional con éxito. Materiales y métodos: El paciente se colocó en posición park bench, bajo fijación esquelética de 3 puntos, con el asterion como punto mas elevado. Se realizo una incisión en forma de C en la mastoides y se realizo un abordaje dirigido hacia el ángulo pontocerebeloso. Resultados: Se logró realizar el clipaje del aneurisma de forma satisfactoria, con un buen resultado clínico del paciente, quien fue egresada a los 4 días sin déficit neurológico. Conclusión: El abordaje retrosigmoideo es una opción terapéutica para el manejo de los aneurismas ubicados en el ángulo pontocerebeloso, específicamente del AICA distal y también se puede usar incluso para los aneurismas distales del PICA.

Background: Cerebral aneurysms of the posterior circulation, representing only 8 to 10% of the total cerebral aneurysms, but the aneurysms of the anteroinferior cerebellar artery (AICA) are very rare, so there is no management algorithm for these lesions, anatomical knowledge of vascular and skull base are known for the treatment of these lesions, in relation of the surgical approach, we can identify, the far lateral, retrosigmoid, orbitozigmatic or presigmoid approaches, which depends on the size and location of aneurysm, either distal or proximal. We present this case, which we treated through a conventional retrosigmoid approach, which offers us a sufficient surgical corridor, without the need for a broader approach, in this case it was a distal AICA aneurysm, located in the meatal segment, which was found in the middle neurovascular complex of the pontocerebellar angle, very close to the cranial nerves V, VII and VIII. Objective: Demonstrate that distal aneurysms of AICA can be managed using a successful conventional retrosigmoid approach. Results: The clipping of the aneurysm was achieved satisfactorily, with a good clinical result of the patient, who was discharged at 4 days without neurological deficit. Conclusion: The retrosigmoid approach is a therapeutic option for the management of aneurysms located in the pontocerebellar angle, specifically of the distal AICA and can also be used even for distal aneurysms of the PICA.

A 3D-Computed Tomography Angiography Study to Help in Surgical Planning for Retrosigmoid Craniotomies

Aims and Objectives: It is impossible to precisely anticipate the course of the transverse and sigmoid sinuses and theirindividual relationship to superficial landmarks such as the asterion during retrosigmoid approaches. This study was done todetermine the position of the asterion and the relationship between asterion and the transverse-sigmoid sinus junction (TSSJ)in making precise burr hole without damaging sinuses during retrosigmoid craniotomies.Materials and Methods: Computed tomography (CT) angiography was performed in 50 patients to obtain 3D-CT volumerendering images of cranial bone and dural sinuses. After delineating the sinuses, by simple restructuring using software andopacity modulation, bone image is reinforced. Asterion type, distance from the tip of mastoid process to asterion and root ofzygoma (ROZ) to asterion, and location of asterion in relation to TSSJ and distance between asterion and TSSJ were analyzedand measured.Results: The incidence of type 1 (presence of sutural bones) in our study was 24% and type 2 (absence of sutural bones) was76%. There was no statistically significance in the side and gender differences. The distance between the asterion and fromthe ROZ was 54.70 ± 3.68 on the right side and 54.32 ± 3.41 on the left side (P-0.612). The distance between asterion and tipof mastoid was 50.51 ± 2.67 on the right side and 50.12 ± 3.06 on the left side (P-0.716). The asterion was located on the T-Ssinus complex in 36 (72%) cases. The asterion was below the T-S sinus complex in 13 (26%) cases, and above the T-S sinuscomplex in only 1 (2%) cases.Conclusion: 3D-CT volume rendering imaging is capable of accurately visualizing the bony landmark and dural sinuses. Aneasy and simple restructured image provides precision and safety for the patient by ready and easy localization of asterionand TSSJ. This study was done to show that the previous cadaver-based anatomical studies can be done now in a moresophisticated and accurate manner with the latest technological advancements. This offers new options for anatomic researchand morphometric investigations.

Localización preoperatoria de la trepanación inicial en el abordaje retrosigmoideo. Revisión de literatura y aplicación quirúrgica / Preoperative location of the initial trepanation in the retrosigmoid approach. Literature review and surgical application

Objetivo: Evaluar una técnica eficaz y reproducible que permita determinar el sitio de la trepanación inicial en el abordaje retrosigmoideo. Materiales y métodos: Se empleó una muestra de 22 pacientes a fin de analizar la relación de la transición transverso ­ sigmoidea (TTS) con el asterion y la ranura digástrica. Todos los casos contaban con TC de cortes finos (1 mm de espesor). Se subdividieron los pacientes en dos grupos. Grupo 1: pacientes con patologías variables, sin alteraciones estructurales en la fosa posterior. Grupo 2: pacientes en los que se realizó un abordaje retrosigmoideo con planificación prequirúrgica del sitio de trepanación inicial. Discusión: Las referencias óseas (asterion y punto digástrico) pudieron identificarse en la totalidad de las TC 3D analizadas. Se analizaron las distancias empleando un sistema de coordenadas. La TTS se registró en el 78% de los casos anterior e inferior al asterion. En ningún caso se encontró la TTS superior al asterion, la ubicación en sentido inferior varió entre 0 mm y 25,5 mm (media 12,5 mm). En el plano anteroposterior, se registró una distancia entre -6,41 mm y 14,5 mm (media 4,09 mm), demostrando una gran variabilidad individual, comparable con lo descripto en la literatura. En el grupo 2, pudo predecirse de manera precisa la localización de la TTS, exponiendo la misma con la trepanación inicial. Conclusión: Se describe un método sencillo, eficaz, de libre acceso, que permite la ubicación del keyhole en el abordaje retrosigmoideo

Objective: To assess an effective and reproducible technique that allows determining the emplacement of the initial burr-hole in the retrosigmoid approach. Materials and methods: A sample of 22 patients was used to analyze the relation among the transverse - sigmoid transition (TTS), the asterion and the digastric groove. All cases had a thin-slice, 1-mm-thick Computed Tomography (CT). Patients were subdivided into two groups. Group 1: patients with variable pathologies, without structural modification of posterior fossa anatomy. Group 2: patients in which a retrosigmoid approach was performed with preoperative surgical planning of the initial burr-hole. Discussion: Bone references (asterion and digastric point) could be identified in the totality of the analyzed 3D CT. The distances were measured using a coordinate system. TTS was recorded in 78% of the cases inferior and anterior to the asterion. In no case the TTS was found superior to the asterion. It was 0 mm to 25.5 mm (mean 12.5 mm) inferior; and a distance between -6.41mm to 14.5mm (mean 4.09mm) in the anteroposterior plane was recorded, demonstrating a large individual variability. In group 2, the location of the TTS could be accurately predicted, exposing it with the initial burr-hole. Conclusion: A simple, effective and access free method is described, which allows the emplacement of the keyhole in the retrosigmoid approach

Microsurgical treatment of intra-auditory meningioma / 中华神经医学杂志

Objective:To summarize the surgical methods and experiences of intra-auditory meningioma, and discuss the techniques achieving complete resection of intra-auditory meningioma by retrosigmoid transmeatal approach on the basis of function reservation of the facial nerve and auditory nerve.Methods:The clinical data of 4 patients with intra-auditory meningioma confirmed by surgery and pathology in Xuanwu Hospital of Capital Medical University and Army General Hospital of People's Liberation Army from January 1998 to December 2018 were retrospectively analyzed. All these 4 patients accepted enlargment of the posterior wall of the internal auditory channel via retrosigmoid transmeatal approach to remove the tumors. The electro-audiogram, surgical records, discharge records and follow-up records were noted.Results:Total resection was achieved in all 4 patients; one was derived from the cerebral dura mater of the outside wall of the internal auditory canal, obtaining radical excision (Simpson grading I resection); the other three were derived from the cerebral dura mater of the internal auditory canal, and the epidural adhesion extended to the ventral internal auditory canal, only receiving Simpson grading II resection. The facial nerve and cochlear nerve in three patients were separated and protected by dissection; while the vestibular nerve and cochlear nerve in the left one patient were not found, and only the facial nerve was dissected and preserved. Two patients with preoperative hearing grading H2 and H3 were able to retain effective hearing after surgery, with postoperative hearing grading H3 and H4, respectively; and the other two patients had postoperative hearing grading H5. Postoperative Karnofsky Performance Scale (KPS) scores were 90 in 3 patients and 70 in one patient. There was no perioperative death.Conclusions:Retrosigmoid transmeatal approach is ideal approach for resection of the intra-auditory meningioma. Surgical excision of intra-auditory meningioma should accept the premise of protecting the facial auditory nerve and aim at extensive resection of tumors, including the dura and bone involved by tumors, so as to reduce the chance of recurrence; and it is necessary to open the width of intra-auditory.

Morbidity Rate of the Retrosigmoid versus Translabyrinthine Approach for Vestibular Schwannoma Resection

BACKGROUND AND OBJECTIVES: Controversy related to the choice of surgical approach for vestibular schwannoma (VS) resection remains. Whether the retrosigmoid (RS) or translabyrinthine (TL) approach should be performed is a matter of debate. In the context of a lack of clear evidence favoring one approach, we conducted a retrospective study to compare the morbidity rate of both surgical approaches. SUBJECTS AND METHODS: 168 patients underwent surgical treatment (2007-2013) for VS at our tertiary care center. There were no exclusion criteria. Patients were separated into two groups according to the surgical approach: TL group and RS group. Signs and symptoms including ataxia, headache, tinnitus, vertigo and cranial nerve injuries were recorded pre- and postoperatively. Surgical complications were analyzed. Perioperative facial nerve function was measured according to House-Brackmann grading system. RESULTS: Tumor resection was similar in both groups. Facial paresis was significantly greater in RS group patients preoperatively, in the immediate postoperative period and at one year follow-up (p < 0.05). A constant difference was found between both groups at all three periods (p=0.016). The evolution of proportion was not found to be different between both groups (p=0.942), revealing a similar rate of surgically related facial paresis. Higher rate of ataxic gait (p=0.019), tinnitus (p=0.039) and cranial nerve injuries (p=0.016) was found in RS group patients. The incidence of headache, vertigo, vascular complications, cerebrospinal fluid leak and meningitis was similar in both groups. No reported mortality in this series. CONCLUSIONS: Both approaches seem similar in terms of resection efficacy. However, according to our analysis, the TL approach is less morbid. Thus, for VS in which hearing preservation is not considered, TL approach is preferable.

Reconstruction of anterior inferior cerebellar artery by occipital artery through extended retrosigmoid approach / 中华显微外科杂志

Objective To explore the feasibility of occipital artery(OA) to anterior inferior cerebellar artery (AICA) through the extended retrosigmoid approach,also perform a systemic microanatomical study of OA and AICA with the exposure of extended retrosigmoid approach,find the easy way to perform the procedure.Methods From September,2016 to January,2017,5 adult cadaveric heads injected with colored latex (total 10 sides) were performed the extended retrosigmoid approach,and measured the caliber of distal occipital artery (OA),the final length of the OA harvest,the reliable landmark of the OA harvest,and the distance from the flocculonodular segment of anterior inferior cerebellar artery (AICA) to the OA,the diameter of AICA flocculonodular segment branch.Whole procedure of OA to IACA bypass also be performed.Statistical analysis was performed.Results By the extended retrosigmoid approach,AICA flocculonodular segment could be easily exposure,the average diameter was 1.2 mm,the OA branch could be harvested in average was (72.3±3.3)mm in length from the occipital sulcus,and the average distance between occipital sulcus and AICA flocculonodular segment was (47.6±l.9)mm.The bypass procedure also could be performed through the proper corridor.Conclusion The Extended retrosigmoid approach is a safe and efficient way to perform the OA-AICA bypass procedure,and the procedure is easier to be performed than other surgical approaches.

Surgical strategies and techniques of petroclival meningiomas by trans-subtemporal combined with suboccipital retrosigmoid keyhole approaches / 中华神经医学杂志

Objective To summary the microsurgical strategies and techniques of petroclival meningiomas by trans-subtemporal combined with suboccipital retrosigrnoid keyhole approaches to raise the removal rate and improve the prognosis.Methods The clinical data of consecutive 26 patients with petroclival meningiomas,admitted to our hospital from January 2011 to December 2015 and accepted microsurgical treatment,were reviewed retrospectively;7 of them were guided by neuronavigation,8 were performed under neuroelectrophysiological monitoring,and 11 were guided by neuronavigation combined intraoperative MRI or neuroelectrophysiological monitoring.The operative methods and techniques,tumor resection rate and Kamofsky performance scale (KPS) scores before and after operation were analyzed.Results Of all patients who underwent surgical treatment by trans-subtemporal combined with suboccipital retrosigmoid keyhole approaches,gross total tumor resection (Simpson Ⅰ-Ⅱ) was achieved in 23 patients (88.5％),subtotal (Simpson Ⅲ-Ⅳ) in 3 patients (1 1.5％).Six patients (23.1％) had cranial nerve deficit postoperatively.No mortality which related with operation was noted.Patients were followed up for 3-35 months,23 patients had KPS scores ≥70,and 3 patients had KPS ＜70;no tumor recurrence or progression was noted.Conclusion The trans-subtemporal combined with suboccipital retrosigmoid keyhole approaches are safe,effective and minimally invasive for resection of petroclival meningiomas;mastering the operation strategies and intraoperative skills is conducive to improve the efficacy of surgery.

Suboccipital retrosigmoid key hole approach in surgical treatment of cerebellopontine angle meningiomas: a clinical analysis of 32 cases / 中华神经医学杂志

Objective To discusses the role of suboccipital retrosigmoid approach in surgical treatment of cerebellopontine angle meningiomas.Methods The clinical data of 32 patients with cerebellopontine angle meningiomas,underwent microsurgery through suboccipital retrosigmoid approach in our hospital from January 1998 and December 2014,were analyzed retrospectively.The treatment efficacy was analyzed.Results In these 32 patients,all of them received tumor removal.After the operation and during the follow-up,the preoperative symptoms and signs disappeared in 22 patients,and relieved in 7.The cranial nerve deficit was unchanged in 3;new neurological deficit was presented in 5,and 8 months-3 years follow up showed that excepted for two patients with permanent damage,the other 3 patents got recovery within 3-6 months of follow up.No tumor recurrence was noted.Conclusion Suboccipital retrosigmoid approach offers excellent exposure to cerebellopontine angle region in surgical treatment of cerebellopontine angle meningiomas,enjoying tiny operational trauma,quick recovery and few complications.

Microsurgical management of petroclival meningiomas combined trans-subtemporal and suboccipital retrosigmoid keyhole approach / 北京大学学报(医学版)

Objective:With the development of modern skull base minimally invasive technology mature and neural radio surgery techniques,it is necessary to re-examine the therapeutic strategy for the treat-ment of petroclival meningiomas.To sum up the operative experience and methods in microsurgical resec-tion of petroclival meningiomas by the combining trans-subtemporal and suboccipital retrosigmoid keyhole approach.To explore the minimally invasive operation approach of petroclival meningiomas,to raise the removal degree and to improve the postoperative result using this approach.Methods:The clinical data of the consecutive 21 patients with the petroclival meningiomas were reviewed retrospectively.The meth-od,degree of tumor resection,techniques of the combining keyhole approach,Karnofsky performance score (KPS)before and after operation were also analyzed.The neuronavigation guided operation was performed in 9 cases,and 12 cases were operated in the neuroelectrophysiological monitoring.Results:Total excision of the tumor resection (Simpson,Ⅰ -Ⅱlevels)was conducted in 18 cases (85.7%,18 /21),and 3 patients underwent close resection (Simpson Ⅲ level,14.3%,3 /21).Postoperative three-dimensional CT showed good lock bone flap restoration;Postoperative pathology confirmed meningioma. Postoperative cranial nerve dysfunction or new original nerve dysfunction were aggravated in 5 cases (23.8%),including transient trochlear nerve (3 cases),abducent nerve (1 case),and the motor branch of trigeminal nerve paralysis (1 case).Abducent nerve paralysis (1 case)appeared,with hearing impairment.After the 3-month follow-up,11 cases had the same KPS aspreoperation,7 cases improved,and 3 cases not improved.The KPS score was 77.14 ±23.12 on average,and there was no statistically significant difference compared with that before operation (P >0.05 ).The postoperative follow-up for half a year showed fluent speaking and writing in 19 cases (KPS 70 or higher),and general recovery in 2 cases (KPS <70).The postoperative follow-up for 3 -29 months showed no tumor recur-rence or progress.Conclusion:The combining trans-subtemporal and suboccipital retrosigmoid keyhole approach is simple,safe,and minimally invasive,and an ideal operation approach of petroclival menin-gioma.To master the operation skills and the intraoperative matters needing attention in the operation,is favorable to improve the resection rate and curative effect.

Keyhole craniotomy for cholesteatmas in the cerebellopontine angle region presenting as trigeminal neural-gia / 中国神经精神疾病杂志

Objective To investigate the clinical utility of keyhole craniotomy for Cholesteatmas in the cerebello-pontine angle region presenting as Trigeminal neuralgia by using keyhole craniotomy. Methods Clinical data of 35 pa-tients with Cholesteatmas in the cerebellopontine angle region presenting as Trigeminal neuralgia was analyzed retrospec-tively. All patients received suboccipital retrosigmoid keyhole craniotomy. Thirty cases who received conventional craniot-omy group were served as control group. A comparative analysis was conducted to assess the difference between these two groups in microsurgical methods, effects and complications. Results All patients were confirmed with MR diagnosis. In keyhole group, all patients had no pain symptoms of trigeminal neuralgia after surgical operation. The symptoms disap-peared immediately in 33 cases and gradually disappeared in 2 cases within one month following keyhole craniotomy. The tumors were totally removed in 25 cases and almost completely in 10 cases. The surgical duration was shorten in key-hole group than in conventional group (126±48 vs. 216±66 min;t=2.536, P<0.05). The amount of bleeding was smaller in keyhole group than in conventional group (91.3±52.2 vs. 186.3±65.4 mL;t=2.163, P<0.05). Postoperative neurologi-cal function was assessed in House-Brackmann. In keyhole group, there were 32 cases in class Ⅰ and 3 in grade Ⅱ. Two patients had hearing loss which was improved gradually in three months. In conventional group, there were 25 cases in class Ⅰ and 5 in grade Ⅱ (χ2=4.158, P<0.05). Postoperative hearing evaluation (AAO-HNS) revealed that there were 33 cases in grade A , and 2 in grade B in the keyhole group, whereas there were 27 cases in grade A and 3 in grade B in the conventional group(χ2=5.167, P<0.05). There were no relapse of tumors and death during 3 month to 5 years follow-up. Conclusions The suboccipital retrosigmoid keyhole craniotomy is a valid choice for Cholesteatmas in the cerebellopontine angle region presenting as Trigeminal neuralgia.

Surgical exposure of the internal auditory canal through the retrosigmoid approach with semicircular canals anatomical preservation / Avaliação da exposição do fundo do conduto auditivo interno através do acesso retrosigmóide-transmeatal

Objective Evaluate the feasibility of an adequate exposure with anatomical preservation of labyrinth structures through retrosigmoid transmeatal approach (RSA) in surgeries for resection of acoustic neuromas/vestibular schwannomas (VS). Method Thirty patients underwent surgical resection and were preoperatively evaluated with fine slice high definition CT scans and 3D-MRI volumetric reconstructions. Extension of internal auditory canal (IAC) opening during surgery was measured using 3 mm right-angle calibrated hook and neuronavigation parameters. Postoperatively, the extension of IAC opening and integrity of the labyrinth were confirmed through preoperatively images procedures. Results The preoperative length of IACs varied between 7.8 and 12.0 mm (mean 9.3 mm, SD 0.98, 95%CI 8.9 to 9.6, and median 9.0 mm). Postoperative images demonstrated adequate opening of the IAC and semicircular channels integrity. Conclusion A complete drilling of the posterior wall of IAC through the RSA is feasible and allows direct visualization of the IAC-fundus without damaging the semicircular canals. .

Objetivo Avaliar a possibilidade de exposição adequada preservando anatomia das estruturas labirínticas pelo acesso retrosigmóide-transmeatal (RSA) nas ressecções de schwannomas do vestibular (VS). Método Trinta pacientes foram submetidos à ressecção cirúrgica e avaliados no pré-operatório com tomografias de alta definição e reconstruções de ressonância magnética 3D. A extensão da abertura do conduto auditivo interno (CAI) foi medida e confirmada com parâmetros de neuronavegação. No pós-operatório, a extensão da abertura e a integridade do labirinto foram confirmadas por imagens de tomografia computadorizada. Resultados A extensão do CAI no pré-operatório apresentou variação de 7,8-12 mm (média 9,3 mm, DP 0,98, IC95% de 8,9-9,6 e mediana 9 mm). Imagens pós-operatórias demonstraram abertura adequada do IAC e integridade dos canais semicirculares. Conclusão A abertura completa da parede posterior do CAI pelo RSA é possível e permite a visualização direta do fundo do conduto sem prejudicar os canais semicirculares. .

Abordaje retrosigmoideo / Retrogigmoid approach

OBJETIVO: describir en forma detallada, paso a paso, la realización de un abordaje retrosigmoideo. DESCRIPCIÓN: posición: existen 3 posiciones descritas para la realización de este abordaje, semisentada, decubito dorsal y en banco de plaza. Incisión: se extiende desde la parte superior del pabellón auricular hasta 2 cm por debajo del vertice mastoideo, y 1 cm medial a la ranura digástrica. Disección de partes blandas: se realiza una disección subperiostica, teniendo especial cuidado con la vena hemisaria mastoidea (posible fuente de embolia aérea). Craniectomía: es necesario identificar previamente algunos puntos anatómicos de referencia para la ubicación de los senos transverso y sigmoides. En la etapa final de la remoción ósea, se procede al fresado de la porción más superior y lateral del abordaje, con la necesaria exposición de la porción inferior del seno transverso y de la porción medial del seno sigmoides. Apertura dural: se realiza una apertura en forma de letra "C" (lado izquierdo), o letra "C invertida" (lado derecho), con base medial, comenzando en la porción superior y medial de duramadre expuesta. Disección microquirúrgica: dependiendo de la ubicación de la patologia a abordar se debe realizar una retracción gentil del hemisferio cerebeloso hacia medial. En la mayoría de los casos es necesario abrir la cisterna cerebelobulbar, con el objeto de evacuar LCR. CONCLUSIÓN: el refinamiento alcanzado actualmente hace que el abordaje retrosigmoideo sea el más utilizado para el tratamiento de las múltiples patologías ubicadas en la región del ángulo pontocerebeloso. El acceso que proporciona esta vía a la mayoría de los nervios craneales que se encuentran en la fosa posterior, y a sus complejos neurovasculares correspondientes, lo convierte en un abordaje de obligatorio aprendizaje para todo neurocirujano

OBJECTIVE: the aim of this paper is to describe, step by step, the retrosigmoid approach to accessing the cerebellopontine angle (CPA). DESCRIPTION: patient position: three potential positions have been described for this approach: semi-sitting, dorsal decubitus and park bench. Incision: The incision extends from the top of the ear to 2 cm below the mastoid apex, and 1 cm medial to the digastric groove. Soft tissue dissection: A subperiosteal dissection is performed, taking special care to avoid the mastoid emissary vein. CRANIOTOMY: At the outset, it is necessary to identify certain anatomical landmarks to localize the transverse and sigmoid sinuses. Dural opening: The dural incision is made in the shape of the letter "C" on the left side or an inverted letter "C" on the right. Microsurgical dissection: Depending on the location of the pathology being treated, it may be necessary to perform gentle cerebellar retraction medially. CONCLUSIONS: the refinements now achieved with the retrosigmoid approach make it the most widely-used approach for the treatment of lesions located within the CPA. The access provided by this approach to the vast majority of the cranial nerves in the posterior fossa, as well as their neurovascular complexes, makes it a mandatory approach for all neurosurgeons to learn

Morphologic measurement of entry points and landmarks of retrosigmoid approach using volume rendering with thin-section computed tomography and its significance / 吉林大学学报(医学版)

Objective To research the jugular foramen,internal auditory pore (IAP)and the turning point between its components by imageological methods and to provide theoretical basis for retrosigmoid approach in the operation of acoustic neurinoma.Methods The skulls of 100 volunteers were scanned to get the final result with thin-section computed tomographic image. High-resolution spiral CT multiplane reformation was used to reform images that were parallel to the Frankfort horizontal plane to measure the distance between the turning point of retrosigmoid (A),the edge of jugular foramen(B)and the lower edge of the internal auditory canal(C)(denoted AC,AB,BC) and the shortest distance from the jugular foramen to AC.The angles between AC,AB and sagittal axis(α,β) were measured.Results The distance of AC was (44.94 ± 3.84)mm,the distance of AB was (43.68 ± 4.56)mm.The distance of BC was (6.15 ±2.04)mm,and the shortest distance between jugular foramen and AC was (5.21±0.23)mm.The angleαwas measured as (39.50±4.74)°,and the angleβwas measured as (46.35± 5.51)°.Conclusion The research measure the distance and angle between entry points and landmarks of retrosigmoid approach and the safe distance.

Delayed Dural Arteriovenous Fistula after Microvascular Decompression for Hemifacial Spasm

Dural arteriovenous fistula (AVF) is very rare, acquired lesion that may present with intracranial hemorrhage or neurological deficits. The etiology is not completely understood but dural AVF often has been associated with thrombosis of the involved dural sinuses. To our knowledge, this is the first well documented intracranial hemorrhage case caused by dural AVF following microvascular decompression for hemifacial spasm. A 49-year-old male patient had left microvascular decompression of anterior inferior cerebellar artery via retrosigmoid suboccipital craniotomy. The patient was in good condition without any residual spasm or surgery-related complications. However, after 10 months, he suffered sudden onset of amnesia and dysarthria. Computed tomography and magnetic resonance imaging revealed the presence of dural AVF around the left transverse-sigmoid sinus. The dural AVF was treated with Onyx(R) (ev3) embolization. At the one-year follow up visit, there were no evidence of recurrence and morbidity related to dural AVF and its treatment. This case confirms that the acquired etiology of dural AVF may be associated with retrosigmoid suboccipital craniotomy for hemifacial spasm, even though it is an extremely consequence of this procedure.

Three-dimensional individual digital anatomy for microsurgery of cerebellopontine angle region tumor / 中华显微外科杂志

Objective To summary the microsurgery clinical experience of 21 patients with cerebellopontine angle tumor by the help of three dimensional individual digital anatomy. And to evaluate the value of three dimensional individual anatomy in the treatment of tumors in cerebellopontine angle. Methods Between January 2011 and November 2011,21 patients with various cerebellopontine angle tumor,managed at the Third Affiliated Hospital of Sun Yat-Sen University, underwent CTA scan, and reconstruct the local anatomy by 3D view software. According to the individual anatomical model, the microsurgery program by restrosig moid approach was developed. Results All patients had reposition of the bone flap at original site after craniectomy during the same operative setting mentioned above with retrosigmoid approach. No complication was noted.Patients did not have any delayed postcraniectomy pain at operation site.Postoperative computed tomography of the skull showed good healing and shaping of the suboccipital bone at the surgical region. Conclusion With the help of three dimensional individual anatomy, the microsurgery of cerebellopontine angle tumor underwent less postoperative complications.This study provides a safe and effective individualized microsurgical methods by restrosig moid approach.

Retrosigmoid Approach in the Removal of Vestibular Schwannoma

BACKGROUND AND OBJECTIVES: The use of several approaches, involving different cerebellopontine angles, has enabled vestibular schwannoma removal to be tailored to each patient's pathology and physiological status. The retrosigmoid approach provides simple and direct access to cerebello-pontine angle lesions. SUBJECTS AND METHODS: We retrospectively assessed outcomes in 35 consecutive patients who underwent vestibular schwannoma removal via the retrosigmoid approach. RESULTS: Of the 35 patients, 12 were men and 23 women; their age was 52.5+/-10.4 years (range, 35-75 years). One tumor was small (3 cm). Symptoms included hearing disturbance (31 patients, 89%), tinnitus (14 patients, 40%), headache (12 patients, 34%), vertigo (11 patients, 31%), and facial palsy (9 patients, 25%). Postoperative complications included facial palsy, intracranial hemorrhage, dysphagia, and disseminated intravascular coagulopathy, with facial palsy remaining permanently. Four patients (11.4%) had tumor regrowth, at a mean of 36.3 months after primary surgery. The mean diameter of regrowing tumors was 20.5+/-4.4 mm (range 14.5-25.0 mm). CONCLUSIONS: The retrosigmoid approach for vestibular schwannoma removal was associated with higher rates of facial palsy and hearing loss. This approach, however, can minimize injury to the lower cranial nerve.

Retrosigmoid Approach in the Removal of Vestibular Schwannoma

BACKGROUND AND OBJECTIVES: The use of several approaches, involving different cerebellopontine angles, has enabled vestibular schwannoma removal to be tailored to each patient's pathology and physiological status. The retrosigmoid approach provides simple and direct access to cerebello-pontine angle lesions. SUBJECTS AND METHODS: We retrospectively assessed outcomes in 35 consecutive patients who underwent vestibular schwannoma removal via the retrosigmoid approach. RESULTS: Of the 35 patients, 12 were men and 23 women; their age was 52.5+/-10.4 years (range, 35-75 years). One tumor was small (3 cm). Symptoms included hearing disturbance (31 patients, 89%), tinnitus (14 patients, 40%), headache (12 patients, 34%), vertigo (11 patients, 31%), and facial palsy (9 patients, 25%). Postoperative complications included facial palsy, intracranial hemorrhage, dysphagia, and disseminated intravascular coagulopathy, with facial palsy remaining permanently. Four patients (11.4%) had tumor regrowth, at a mean of 36.3 months after primary surgery. The mean diameter of regrowing tumors was 20.5+/-4.4 mm (range 14.5-25.0 mm). CONCLUSIONS: The retrosigmoid approach for vestibular schwannoma removal was associated with higher rates of facial palsy and hearing loss. This approach, however, can minimize injury to the lower cranial nerve.