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Axial bone window CT scan of a right-sided mastoid bone. (a) Predissection of a medially displaced sigmoid sinus. (b) Postdissection showing no mastoid air cells remnants and the cortical bone of the sigmoid sinus, Trautmann's triangle and otic capsule preserved. (TT, Trautmann's triangle; SS, sigmoid sinus; LSCC, lateral semicircular canal; PSCC, posterior semicircular canal; MAC, mastoid air cells)
Source publication
Background:
The presigmoid retrolabyrinthine space is characterized by a widely variable size. The main structure involved in this large variability is the sigmoid sinus. Few studies have attempted to establish a reliable classification of sigmoid sinus to predict the presigmoid retrolabyrinthine space. We used tomographic mapping of human cadaver...
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Citations
... Aslan et al. 31 emphasized that in axial sections, the facial nerve is located 10.5 mm anteromedial to the SS and that this distance makes it easier for the surgeon to locate the facial nerve when they find the SS and that opencavity procedures can be helpful, especially in revision cases. de Melo et al. 32 in their study of cadaver temporal bones classified the SS as medially and laterally localized and stated the distance from the SS dura junction to the facial nerve as 11.74 mm for medial SS and 7.88 mm for lateral SS. The same researchers stated that, theoretically, the risk of facial nerve injury during mastoidectomy may be higher in temporal bones where the SS is laterally displaced. ...
... Aslan et al. 31 emphasized that in axial sections, the facial nerve is located 10.5 mm anteromedial to the SS and that this distance makes it easier for the surgeon to locate the facial nerve when they find the SS and that opencavity procedures can be helpful, especially in revision cases. de Melo et al. 32 in their study of cadaver temporal bones classified the SS as medially and laterally localized and stated the distance from the SS dura junction to the facial nerve as 11.74 mm for medial SS and 7.88 mm for lateral SS. The same researchers stated that, theoretically, the risk of facial nerve injury during mastoidectomy may be higher in temporal bones where the SS is laterally displaced. ...
Objective: In this study, we aimed to analyze the relationship of sigmoid sinus (SS) with external auditory canal, facial nerve and mastoid cells from an anatomical point of view, to define the position of sigmoid sinus during transmastoid, translabyrinthine, retrosigmoid (lateral suboccipital) approaches, in tympanomastoidectomy and posterior cranial fossa surgery.
Methods: In this study, the morphological structures associated with the sigmoid sinus were evaluated in cone beam computed tomography images taken between 2015-2022 years. The images of 68 males and 106 females, aged 18-65 years, obtained from the archive of xxx University Faculty of Dentistry, Department of Oral and Maxillofacial Radiology were analysed.
Results: The most common sigmoid sinus pattern was type II with a rate of 60.8% (n=209); the second was type III with 20.6% (n=71); and the least common was type I with 18.6% (n=64). While the distance between the horizontal line passing through the external auditory canal and facial nerve and the anterior contour of the sigmoid sinus was highest in type I (right 7.26±1.62, left 7.44±.97), it was lowest in type III (right 4, 40±1.50, left 4.84±1.16) (p<0.05).
Conclusion: This study hihglights the importance of the sigmoid sinus position in surgeries, with special reference to otological, neurotological and posterior cranial fossa surgeries. In order to avoid intraoperative complications, each patient should be evaluated preoperatively by appropriate radiological methods.
... Lesser invasive petrosectomies, namely the retrolabyrinthine-transtentorial and the standard presigmoid petrosal approach with partial labyrinthectomy, have been proposed, allowing good rates of hearing preservation but drastically reducing the surgical exposure [139][140][141][142][143]. ...
Simple Summary
Skull base meningiomas have always represented a challenge for neurosurgeons. Despite their histological nature, they may be associated with unfavorable outcomes due to their deep-seated location and the surrounding neurovascular structures. Over time, several corridors have been proposed, each one carrying its own pros and cons. During the last decades, the endoscopic endonasal route has been asserted among the classic routes for a growing number of midline and paramedian lesions. Therefore, the aim of our paper is to present a comprehensive review of the indications and techniques for the management of skull base meningiomas, emphasizing the ambivalent and complementary role of the low and high routes.
Abstract
Skull base meningiomas have always represented a challenge for neurosurgeons. Despite their histological nature, they may be associated with unfavorable outcomes due to their deep-seated location and the surrounding neurovascular structures. The state of the art of skull base meningiomas accounts for both transcranial, or high, and endonasal, or low, routes. A comprehensive review of the pertinent literature was performed to address the surgical strategies and outcomes of skull base meningioma patients treated through a transcranial approach, an endoscopic endonasal approach (EEA), or both. Three databases (PubMed, Ovid Medline, and Ovid Embase) have been searched. The review of the literature provided 328 papers reporting the surgical, oncological, and clinical results of different approaches for the treatment of skull base meningiomas. The most suitable surgical corridors for olfactory groove, tuberculum sellae, clival and petroclival and cavernous sinus meningiomas have been analyzed. The EEA was proven to be associated with a lower extent of resection rates and better clinical outcomes compared with transcranial corridors, offering the possibility of achieving the so-called maximal safe resection.
... This related surgical area is limited by semicircular canals (SCC) anteriorly, superior petrosal sinus (SPS) superiorly, sigmoid sinus (SS) posteriorly, and the jugular bulb (JB), inferiorly, and this area is called as Trautmann's triangle [2]. One of the most important advantages of the presigmoid approach compared to translabyrinthine approaches is fundamentally preserving hearing [8]; the other advantage compared to the retrosigmoid approach is decreasing cerebellar retraction and providing earlier access especially to the pontocerebellar area lesions, but its most important disadvantage is the difficulties resulting from the narrow surgical corridor [13]. ...
... In recent studies, endoscopic procedures that performed with small craniotomy are recommended in order to reduce parenchymal retraction and to provide better surgical exposure and also provide a better postoperative prognosis [2,14,15]. Endoscope may assist sufficiently for tumor resection or microvascular decompression and may provide better visualization of the anatomical structures [8,14,15]. Despite these developments, neurosurgeons have difficulties in surgeries performed by entering these little craniotomy areas with the endoscope due to the narrow area and manipulation limitations. ...
... In our study, four parameters mentioned in the literature were used to evaluate the applicability of the EAPRA approach with pre-op radiological parameters. In literature, the classification made according to whether the line drawn from the posterior border of PSC and LSC tothe SS (Fig. 2) is in the lateral or medial of SS was defined [8]. They proved that the distance between SS and EAC is statistically significantly wider in cases that the line is on the medial of SS compared to cases that it is on the lateral. ...
Purpose
This study aims to evaluate the applicability of the endoscopy-assisted presigmoid retrolabyrinthine approach, advantages, disadvantages, and the applicability of surgery with pre-op radiological parameters; identify important landmarks; and to reveal their relationships with important structures in the surgical field with objective data. Also, we aim to improve the surgical technique for increasing reachable anatomic structure.
Methods
Mastoid drilling and endoscopy-assisted presigmoid retrolabyrinthine approach were performed and endoscopic instruments were used to obtain the three-dimensional pictures. Computed tomography images were evaluated to correlate to the anatomic data.
Results
In terms of pre-operative radiological evaluation of the applicability of the presigmoid approach were investigated with selected radiological parameters. The endoscopy-assisted presigmoid retrolabyrinthine approach applied to cadavers the relationship, distances between important anatomical landmarks, and anatomical structures in the surgical field recorded. The anatomical structures that could reach with the application of the procedure were recorded. The relationship between pre-operative measured radiological parameters and surgical results was evaluated with objective data. Additional combinations to improve this surgical method discussed and the results of our combination were recorded with photographs.
Conclusion
Although the presigmoid retrolabyrinthine approach has facilitated with the assistance of endoscope, it has observed that there are still some difficulties, and it has been concluded that the radiological parameters are useful in evaluating the applicability of this surgery. It observed that this surgery can be performed more effectively with combinations.
... The main criticism to this retrolabyrinthine approach remained in the angle of view and the surgical exposure. The angle of view offered by this approach is restricted to those tumors located within the prepontine region or in the lower clivus, and, in contrast to the translabyrinthine approach, the surgical exposure is quite reduced [34][35][36]. In an attempt to improve the area of exposure, Sekhar et al. [11] added a partial labyrinthectomy to the standard presigmoid petrosal approach to treat 25 patients with petroclival meningioma, conserving hearing function in 80% of patients. ...
The current literature regarding surgical treatment for tumors in the sphenopetroclival (SPC) region is merely scarce. Through a comprehensive literature review, we investigated the indications, outcomes, and complications of different surgical approaches to the SPC meningiomas. Given its complicated relationship between these slow-progression tumors and some critical neurovascular structures in the SPC region, surgical treatment of these tumors faces the challenge of achieving a maximal grade of resection, while preserving patient functionality. The development of new surgical techniques and approaches in recent years have permitted the advancement in the treatment of these tumors, with acceptable rates of morbidity and mortality. The choice of a surgical approach as a treatment for the lesion depends mainly on the type of tumor extension, surgeon’s preferences, and the displacement of neurovascular structures. Rather than focusing on one single strategy of treatment, the skull-base surgeon should tailor the approach based on the origin and features of the lesion; as well as the peculiarities of the surgical anatomy. This strategy aims to decrease morbidity and to optimize tumor resection and patient quality of life.
... At the end of the drilling step, a full exposure of the presigmoid dura according to the limits described as the Trautmann's triangle has been achieved (anterior border of the SS, SPS, posterior SCC and third portion of the facial canal) (Fig. 1C) [1]. ...
Background: The retrolabyrinthine approach is classified among the posterior petrosectomies. Its goal is to achieve an enlarged mastoidectomy while sparing the intrapetrous neurotologic structures in order to offer maximal exposure of the posterior cerebellopontine angle compound.
Methods: The stages of the procedure are subsequently the skeletonization of the sigmoid sinus, wide opening of the mastoid antrum and exposure of the semicircular canals. We present herein the technique, indications and limitations of the retrolabyrinthine approach.
Conclusion: The retrolabyrinthine approach is a demanding technique. Nowadays the retrolabyrinthine approach is routinely combined to additional resections of the petrous bone, so-called “combined petrosectomies”, to target the jugular foramen or the petroclival area.
... There have been many cadaveric [18][19][20][23][24][25][26][27][28][29][30] and radiologic [21,22,26,[31][32][33][34][35][36] studies investigating the variability of the SS, as well as its anatomic relationships to other structures within the temporal bone. However, the intricacies of temporal bone anatomy can make morphological analysis in two-dimensions (2D) challenging. ...
... There have been many cadaveric [18][19][20][23][24][25][26][27][28][29][30] and radiologic [21,22,26,[31][32][33][34][35][36] studies investigating the variability of the SS, as well as its anatomic relationships to other structures within the temporal bone. However, the intricacies of temporal bone anatomy can make morphological analysis in two-dimensions (2D) challenging. ...
Objectives
The primary objective of this study was to use high-resolution micro-CT images to create accurate three-dimensional (3D) models of several intratemporal structures, and to compare several surgically important dimensions within the temporal bone. The secondary objective was to create a statistical shape model (SSM) of a dominant and non-dominant sigmoid sinus (SS) to provide a template for automated segmentation algorithms.
Methods
A free image processing software, 3D Slicer, was utilized to create three-dimensional reconstructions of the SS, jugular bulb (JB), facial nerve (FN), and external auditory canal (EAC) from micro-CT scans. The models were used to compare several clinically important dimensions between the dominant and non-dominant SS. Anatomic variability of the SS was also analyzed using SSMs generated using the Statismo software framework.
Results
Three-dimensional models from 38 temporal bones were generated and analyzed. Right dominance was observed in 74% of the paired SSs. All distances were significantly shorter on the dominant side (p < 0.05), including: EAC – SS (dominant: 13.7 ± 3.4 mm; non-dominant: 15.3 ± 2.7 mm), FN – SS (dominant: 7.2 ± 1.8 mm; non-dominant: 8.1 ± 2.3 mm), 2nd genu FN – superior tip of JB (dominant: 8.7 ± 2.2 mm; non-dominant: 11.2 ± 2.6 mm), horizontal distance between the superior tip of JB – descending FN (dominant: 9.5 ± 2.3 mm; non-dominant: 13.2 ± 3.5 mm), and horizontal distance between the FN at the stylomastoid foramen – JB (dominant: 5.4 ± 2.2 mm; non-dominant: 7.7 ± 2.1). Analysis of the SSMs indicated that SS morphology is most variable at its junction with the transverse sinus, and least variable at the JB.
Conclusions
This is the first known study to investigate the anatomical variation and relationships of the SS using high resolution scans, 3D models and statistical shape analysis. This analysis seeks to guide neurotological surgical approaches and provide a template for automated segmentation and surgical simulation.
... [1][2][3][4] The Trautmann triangle is bound superiorly by the superior petrosal sinus, posteriorly by the SS, anteriorly by the PSCC, and anteroinferiorly by the jugular bulb (JB). [4][5][6] There have been many attempts to classify the SS in the past based on the location of the SS and on the exposure of the Trautmann triangle, but none of them classify the SS in relation to the surrounding vital structures with consideration to the volume of the mastoid as a function of the position of the SS. The various classifications are listed in ►Table 4. 1,2,4 In 1993, Ichijo et al 7 proposed a classification of shapes of the SS. ...
... The position of the SS significantly affects the exposure of the endolymphatic sac via a transmastoid approach, and of the CPA/petroclival fissure area via a presigmoid retrolabyrinthine approach. 5,6 The exposure of the posterior cranial fossa via a presigmoid retrolabyrinthine approach depends on the positional relationship of the SS and of the PSCC in an anteroposterior plane and of the Superior Petrosal Sinus (SPS) and of the JB in a superoinferior plane. 5,6,9 The more forward placed the SS is, the more constricted the exposure via this corridor gets. ...
... 5,6 The exposure of the posterior cranial fossa via a presigmoid retrolabyrinthine approach depends on the positional relationship of the SS and of the PSCC in an anteroposterior plane and of the Superior Petrosal Sinus (SPS) and of the JB in a superoinferior plane. 5,6,9 The more forward placed the SS is, the more constricted the exposure via this corridor gets. This leads to twofold consequences. ...
Introduction Sigmoid sinus (SS) variations have been classified variously in the literature. These classifications suffer from some form of shortcoming from a clinical point of view for their application.
Objective We propose a clinically relevant classification of the SS in relation to the posterior semicircular canal (PSCC) and to the exposure of the presigmoid dural plate. The positioning of the SS was analyzed with reference to the volume of the mastoid and to the level of mastoid pneumatization.
Materials and Methods A total of 94 formalin-preserved human cadaveric temporal bones were microdissected to carry out a complete mastoidectomy. The SS, the presigmoid dural plate, and the PSCC were exposed, and the position of the former was analyzed in relation to the latter two in order to classify the position of the SS into three grades.
Results Grade I had the best exposure of the presigmoid dura and of the PSCC, while grade III had the poorest exposure of the presigmoid dura and of the PSCC. Grade I SS was associated with good pneumatization and higher mastoid volumes compared with grades II and III.
Conclusions The SS exhibits considerable anatomic variability. A favorable positioning of the SS is associated with a large mastoid volume and pneumatization. A careful preoperative study of the imaging may help in understanding the positioning of the SS and the safety of various transmastoid approaches.
... Previously reported anatomical landmarks of the presigmoid retrolabyrinthine approach includes the aerated of the petrous bone and the height of the jugular bulb, the position of the sigmoid sinus, the size of the Trautmann triangle, and petrous slope [4][5][6][7]. Few studies have described the exposure of inner auditory canal and the size of the retrolabyrinthine space by using this approach [8,9]. ...
Background: The surgical approach of acoustic neuroma includes translabyrinthine, transcranial fossa, suboccipital retrosigmoid sinus, and presigmoid retrolabyrinthine approach.
Aims/Objective: To provide the anatomical basis for the surgical selection of presigmoid retrolabyrinthine approach by measuring the anatomical parameters of retrolabyrinthine space of the petrous bone by high-resolution CT.
Material and methods: A retrospective study of 208 high-resolution CT (HRCT) images of 104 patients examined in our hospital were analyzed retrospectively. Forty-nine males and 55 females were included in this study. Lines were drawn on the HRCT to measure the morphological data for pre-operational assessment.
Result: Morphological data were retracted from HRCT, for preoperational assessment.
Conclusion and significance: Using the standard postprocessing images of temporal bone HRCT can predict the size of the retrolabyrinthine space and the degree of exposure to the inner auditory canal, providing an important anatomical index for the choice of presigmoid retrolabyrinthine approach.
... [28] Despite the known variability of this dural exposure, detailed anatomic studies to date have only involved small cadaveric series. [8,28] Several radiographic studies have also examined other characteristics of the temporal bone, including degree of aeration of the mastoid portion in relation to the sigmoid sinus and labyrinth. Because mastoid aeration can influence the ease of exposure of critical structures and the degree of visualization of the petroclival region from the posterolateral approach, this is another aspect of patient anatomy that can be considered as part of the preoperative planning. ...
... Given that the individual variability of this operating space has been demonstrated only in small cadaveric studies, [8,28] a systematic radiographic assessment of a patient's temporal bone can allow for a more nuanced preoperative planning. We sought to quantify anatomical constraints that may affect either the decision to use a particular approach (retrosigmoid versus presigmoid) or inform the need to modify the presigmoid approach. ...
... They noted a theoretical increased risk of injury to the facial nerve because of its close relation with the sigmoid sinus. [8] While a laterally displaced sigmoid sinus can be ameliorated to some degree with a retrosigmoid bone exposure, ligation of the superior petrosal sinus, and tentorial splitting to allow posterior retraction of the sigmoid sinus, it nevertheless requires significantly more time and incurs more risk. In a cadaveric study assessing the impact of sigmoid sinus variation on the Trautmann's triangle exposure, Sarmiento and Eslait found the degree of lateral displacement to be correlated with decreasing Trautmann's triangle area. ...
Background
Lesions of the petroclival fissure are difficult to access surgically. Both retrosigmoid and presigmoid retrolabyrinthine approaches have been described to successfully treat these complex tumors. The retrosigmoid approach offers quick and familiar access, whereas the presigmoid retrolabyrinthine approach reduces the operative distance and the need for cerebellar retraction. The presigmoid retrolabyrinthine approach, however, is constrained by anatomical limits that can be subject to patient variation. We sought to characterize the surgically relevant variation to guide preoperative assessment.
Methods
One hundred and seventy-seven high-resolution computed tomography scans of the head (without preexisting pathology) were reviewed. Three hundred and fifty-four temporal bone scans were analyzed for level of aeration, size of Trautmann's triangle dura, and petrous slope. Petrous slope is the angle between the anterior sigmoid sinus and the petroclival fissure at the level of the internal acoustic canal.
Results
Trautmann's triangle area had a mean of 185.15 mm² (range 71.4–426.7 mm²). Petrous slope had a mean value of 149° (range 106–178°). Increasing aeration was found to be correlated with decreasing petrous slope and decreasing Trautmann's triangle area.
Conclusion
The presigmoid retrolabyrinthine approach is uniquely confined. Variations in temporal bone anatomy can have dramatic impacts on the operative time, risk profile, and final exposure. Preoperative assessment is critical in guiding the surgeon on the appropriateness of approach. Preoperative measurement of Trautmann's triangle, petrous slope, and aeration can help to reduce surgical morbidity.
