Juan M. Revuelta Barbero

Quantitative analysis of the surgical exposure and surgical freedom between transcranial and transorbital endoscopic anterior petrosectomies to the posterior fossa

OBJECTThis study proposes a variation of the transorbital endoscopic approach (TOEA) that uses the lateral orbit as the primary surgical corridor, in a minimally invasive fashion, for the posterior fossa (PF) access. The versatility of this technique was quantitatively analyzed in comparison with the anterior transpetrosal approach (ATPA), which is commonly used for managing lesions in the PF.METHODSAnatomical dissections were carried out in 5 latex-injected human cadaveric heads (10 sides). During dissection, the PF was first accessed by TOEAs through the anterior petrosectomy, both with and without lateral orbital rim osteotomies (herein referred as the lateral transorbital approach [LTOA] and the lateral orbital wall approach [LOWA], respectively). ATPAs were performed following the orbital approaches. The stereotactic measurements of the area of exposure, surgical freedom, and angles of attack to 5 anatomical targets were obtained for statistical comparison by the neuronavigator.RESULTSThe LTOA provided the smallest area of exposure (1.51 ± 0.5 cm2, p = 0.07), while areas of exposure were similar between LOWA and ATPA (1.99 ± 0.7 cm2 and 2.01 ± 1.0 cm2, respectively; p = 0.99). ATPA had the largest surgical freedom, whereas that of LTOA was the most restricted. Similarly, for all targets, the vertical and horizontal angles of attack achieved with ATPA were significantly broader than those achieved with LTOA. However, in LOWA, the removal of the lateral orbital rim allowed a broader range of movement in the horizontal plane, thus granting a similar horizontal angle for 3 of the 5 targets in comparison with ATPA.CONCLUSIONSThe TOEAs using the lateral orbital corridor for PF access are feasible techniques that may provide a comparable surgical exposure to the ATPA. Furthermore, the removal of the orbital rim showed an additional benefit in an enhancement of the surgical maneuverability in the PF.

Letter to the editor: endoscopic transorbital route to the petrous apex: a feasibility anatomic study

To the editor: We read with great interest the article entitled BEndoscopic transorbital route to the petrous apex: a feasibility anatomic study^ by Di Somma et al. [5]. The authors provide a detailed step-by-step description of the dissection for reaching the petrous apex via the transorbital corridor with direct access to three intradural surgical spaces. In addition, the authors quantified the volume of bone removal at the petrous apex achieved with this approach and complemented it with a clear 3D illustration of their method. The scientific work is excellent and, indeed, is an important contribution to the evolving literature of the transorbital endoscopic approach (TOEA). We agree with the authors’ conclusion that the TOEA provides a feasible minimally invasive pathway to the petrous apex. Coincidentally, in the past year, we conducted anatomical research in the same topic by quantitatively comparing the area of exposure and surgical freedom of the two different transorbital endoscopic techniques to the Kawase’s triangle [7]. It is, therefore, our great interest to learn more about the experts’ opinions on delving further into the complex technical nuances that revolve around this particular topic. That being said, we would like the authors to address the following issues. First, for the initial incision, we carried out a lateral canthotomy and cantholysis, which granted direct access to the lateral orbital corridor with full control of the lateral wall of the orbit. This method not only facilitated rapid access but also, once in middle fossa, allowed for only minimal temporal lobe and dura retraction for sufficient skull-base exposure. By contrast, the authors described orbital access via a superior eyelid incision, which requires meticulous dissection of the eyelid, with potentially undesirable short-term cosmetic sequelae [1]. More importantly, however, in our opinion, given the higher position of entry into the orbit, the use of this strategy, places the surgeon at an angular disadvantage with the middle skull base; granting only limited reach unless significant dura retraction is undertaken. Second, during the elevation of the temporal dura, the authors mention carrying out the dissection of the greater superficial petrosal nerve from posterior to anterior, as typically performed in the transcranial approach [4, 6]. However, admittedly, we faced increased difficulty performing this maneuver through the transorbital corridor. We recognize the importance of this issue, given the cited incidence of petrous bone dehiscence over the geniculate ganglion. Therefore, we would appreciate if the authors could further provide the details of their technique as well as suggest a few Bkey^ pointers for accomplishing such a formidable task in an atraumatic fashion. Third, the current literature of the TOEA generally suggests limiting eyeball displacement to < 1 cm [2, 3]; although specific evidence on this matter remains to be established. Nonetheless, our study abided by these recommendations, which, as we observed, significantly restricted This article is part of the Topical Collection on Neurosurgical technique evaluation

Expanded Endoscopic Endonasal Approach to the Inframeatal Area: Anatomic Nuances with Surgical Implications

BACKGROUND/OBJECTIVEnThe inframeatal area represents a challenging region for skull base surgeons. Various surgical corridors have been described to access this area and frequently are used in combination. Recent studies describe the expanded endoscopic endonasal approach (EEA) as an established route for midline regions, particularly medial to the internal carotid arteries (ICA). We sought to evaluate the accessibility, maneuverability, and freedom of movement of the expanded endoscopic endonasal approach to the inframeatal region.nnnMETHODSnAn EEA combining a middle and an inferior transclival corridor with an infrapetrous and a supracondylar lateral expansion was performed in 5 embalmed human cadaveric heads. The area of exposure and the surgical freedom to access the inframeatal area were calculated. The angle of attack and distances from the lacerum segment of the ICA to several anatomical targets also were measured. Our database was searched to select clinical case examples.nnnRESULTSnThe EEA provided an exposure area of 101.26 ± 16.66 mm2 and an area of surgical freedom of 1208.50 ± 507.01 mm2. The angles of attack in both the sagittal and axial planes were wider at the lacerum segment of the ICA and narrower at the dural entrance zone of cranial nerves VII/VIII. Three chondrosarcomas are presented as case illustrations.nnnCONCLUSIONSnThe EEA is a feasible route to the inframeatal area. This approach provides a safe working corridor for lesions in this region, as shown by the anatomical and clinical findings presented here. Comparative studies and large case series are warranted to further establish its clinical value.

Erratum: Endoscopic Endonasal Transtuberculum Sellae Approach for the Resection of Suprasellar Epidermoid Cyst

[This corrects the article DOI: 10.1055/s-0038-1624590.].

Endoscopic Endonasal Resection of Tuberculum Sellae Meningioma with Utilization of Indocyanine Green

We present the case of a 67-year-old female with an incidental finding of a left-sided tuberculum sellae meningioma on a brain magnetic resonance imaging (MRI) for an unrelated complaint. Formal visual field testing showed a small defect in the inferior nasal and temporal fields of the left eye, compatible with mass effect on the optic nerve by the tumor. An endoscopic endonasal transtuberculum approach with decompression of the left optic nerve was performed using a standard binostril four-hand technique, with the patient positioned supine with the head turned to the right side and tilted to the left, fixed in a three-pin head clamp, under imaging guidance. After exposure, we drilled the tuberculum sellae and the floor of the sella and after opening the dura, the tumor and optic nerve came into view. The tumor was completely removed and we confirmed the patency of all perforating vessels using indocyanine green. Reconstruction was done in a multilayered fashion, using collagen matrix and a nasoseptal flap. Patient had an uneventful postoperative stay and was discharged on postoperative day 3, neurologically stable with no new hormonal deficits. Pathology report confirmed a WHO Grade I meningioma with K i -67 of 1% and 3-month postoperative MRI confirmed a gross total resection and visual fields exam showed a complete recovery. The link to the video can be found at: https://youtu.be/zRmt2aIvX5c .

Endoscopic Endonasal Transplanum–Transtuberculum Sellae Approach for the Resection of a Diaphragma Sellae Meningioma

The endoscopic endonasal approach (EEA) provides a direct access to diaphragma sellae meningiomas. We present a case of a 56-year-old-female with an incidentally diagnosed sellar/suprasellar lesion with no hormonal deficit; thus, she opted for conservative management initially. During her annual follow-up appointment with her ophthalmologist, it was noticed that the patient had right eye peripheral deficit on formal visual field testing. Magnetic resonance imaging (MRI) revealed an enlargement of the sellar/suprasellar mass, causing displacement of the optic chiasm. A transplanum–transtuberculum EEA was performed. Gross-total removal was achieved and closure was done in a multilayer fashion using a collagen matrix, nasoseptal flap. Histopathological examination confirmed a meningioma WHO grade I. There were no intra- or postoperative complications. At 4-year-follow-up, the patient has stable vision and MRI brain showed no recurrence. The link to the video can be found at: https://youtu.be/xY8T9hotlDs .

Endoscopic Endonasal Resection of a Suprasellar Pituitary Adenoma Mimicking Tuberculum Sellae Meningioma in a Patient with an Intrasellar Persistent Trigeminal Artery

A 50-year-old female with an incidentally diagnosed suprasellar lesion was initially managed conservatively due to the presence of an intrasellar persistent trigeminal artery going through the dorsum sellae and fundamentally forming the blood supply of the entire posterior circulation. Serial follow-up brain magnetic resonance imaging (MRI) revealed progressive enlargement of the suprasellar lesion over 4 years period. Surgery was indicated after the initial tumor growth; however, the patient refused surgery for fear of complications related to the persistent trigeminal artery. Two-and-a-half years later, she presented with deterioration of vision. Formal visual field testing revealed a right temporal field defect. Brain MRI demonstrated significantly enlarged suprasellar lesion, most consistent with tuberculum sellae meningioma, exerting mass effect on the optic apparatus. The patient underwent endoscopic endonasal resection of the lesion through a transplanum/transtuberculum approach. Intraoperatively, absence of hypertrophic McConnel arteries, hyperostosis, and the fact that the dura was soft and not under tension was against the diagnosis of tuberculum sellae meningioma. Additionally, the tumor consistency was similar to a pituitary adenoma. A complete resection was accomplished and multilayer skull base reconstruction was performed with no complications. On postoperative day 1 (POD 1), she was operated upon for the evacuation of small suprasellar hematoma associated with vision deterioration. Histopathological examination confirmed the diagnosis of atypical pituitary adenoma with K i -67 labeling index of 4 to 5%. The patient ultimately recovered well with improved vision, and was discharged on POD 4 with no new neurological deficits. At 4 years follow-up, her vision was normalized and brain MRI showed no residual or recurrent lesion. The link to the video can be found at: https://youtu.be/QZmzctjAEbw .

Endoscopic Endonasal Transtuberculum Sellae Approach for the Resection of Suprasellar Intrainfundibular Epidermoid Cyst

A 49-year-old female presented with intense headaches of 3 months duration. Brain magnetic resonance imaging (MRI) was performed and showed a sellar–suprasellar lesion extending into the third ventricle. A presumptive diagnosis of a craniopharyngioma was made. Since the patient did not have any visual deficits, she opted for conservative management. Four months later, she started to have progressive deterioration of vision; thus, surgery was indicated. The patient underwent endoscopic endonasal resection of the lesion through a transtuberculum sellae approach. The patient was positioned supine with the head slightly extended and the face turned to the right side. Following the essence of a binostril four-hand technique, a total gross resection of the lesion was achieved and multilayer skull base reconstruction was performed utilizing collagen matrix and nasoseptal flap; with no intraoperative complications. The patients postoperative course was uneventful with the improvement in her vision, and she was discharged on postoperative day 4 with no new neurological deficits. Histopathological examination confirmed the diagnosis of an epidermoid cyst. Postoperative pituitary gland function was within normal limits except for mild diabetes insipidus for which she is on DDAVP 0.1u2009mg twice daily. At 4 years follow-up, the patient was doing well, her vision was normalized, and brain MRI revealed no evidence of residual or recurrent lesion. The link to the video can be found at: https://youtu.be/OqDFpa_Xq78 .

Endoscopic Endonasal Focal Transclival-Medial Condylectomy Approach for Resection of a Foramen Magnum Meningioma: 2-Dimensional Operative Video

The endoscopic endonasal approach (EEA) provides direct access to foramen magnum meningiomas; however, it often requires extensive exposure including septal flap elevation with septum removal, complete sphenoidotomy, and panclivectomy.We present a case of a 54-yr-old-female with an incidental foramen magnum lesion followed up with serial imaging who presented 10 mo later with progressive neck discomfort and episodes of dizziness, with confirmed tumor progression and further brainstem compression. A focal transclival EEA with medial condylectomy was performed preserving the upper two-thirds of the clivus, the nasal septum, and the sphenoid sinus. Gross total removal of a meningioma WHO Grade-1 was achieved with dura resection on the majority of the tumor (Simpson 2). Closure was achieved with a random pedicled inverted V nasaopharyngeal flap. There were no complications, all symptoms improved, and no recurrence was seen in 12 mo of follow-up.IRB approval was neither required nor saught for this single case report. The patient gave informed consent.

The Eustachian Tube as a Landmark for Early Identification of the Abducens Nerve During Endonasal Transclival Approaches

BACKGROUNDnExpanded endonasal approaches have the potential to injure the abducens nerve (cranial nerve [CN] VI). The nerves root entry zone (REZ) and cisternal segment (CS) are particularly prone to injury during the clivus resection and dural incision of transclival approaches.nnnOBJECTIVEnTo investigate the role of the eustachian tube (ET) as a surgical landmark for the REZ and CS of CN VI.nnnMETHODSnTransclival expanded endonasal approaches were performed bilaterally in 6 fresh-frozen cadaveric specimens (12 sides). Anatomic relationships between ET and CN VI were documented with neuronavigation.nnnRESULTSnThe mean vertical distance from the inferior brainstem point to the horizontal projection of CN VI REZ, CS midpoint, and interdural segment (ID) were 26.38 mm (95% confidence interval [CI] 17.36-35.4), 38.61 mm (95% CI 25.61-51.61), and 42.68 mm (95% CI 30.14-55.22), respectively. The relative vertical distance from the ET to the horizontal projections of the REZ, CS midpoint, and its ID were 6.43 mm (95% CI 3.25-9.61), 18.66 mm (95% CI 11.52-25.8), and 22.72 mm (95% CI 16.02-29.42), respectively. In the axial plane the angles between the ET and (1) the REZ and its midline horizontal projection point, (2) the midpoint and its midline horizontal projection point, and (3) ID and its midline horizontal projection point were 9.81xa0±xa0SD 5.20°, 18.50xa0±xa0SD 4.87°, and 24.71xa0±xa0SD 6.21°, respectively.nnnCONCLUSIONnThe ET may serve as a constant landmark to reliably predict the position of the REZ and CS of CN VI.