Intracranial Breakthrough Through Cavernous Sinus Compartments: Anatomic Study and Implications for Pituitary Adenoma Surgery.
Operative neurosurgery (Hagerstown, Md.)
2022; 23 (2): 115-124
BACKGROUND: Pituitary adenomas (PAs) with cavernous sinus (CS) invasion can extend into the intradural space by breaking through the CS walls.OBJECTIVE: To elaborate on the potential breakthrough route through CS compartments for invasive PAs and describe relevant surgical anatomy and technical nuances, with an aim to improve resection rates.METHODS: Twelve colored silicon-injected human head specimens were used for endonasal and transcranial dissection of the CS walls; ligaments, dural folds, and cranial nerves on each compartment were inspected. Two illustrative cases of invasive PA are also presented.RESULTS: The potential breakthrough routes through the CS compartments had unique anatomic features. The superior compartment breakthrough was delimited by the anterior petroclinoidal ligament laterally, posterior petroclinoidal ligament posteriorly, and interclinoidal ligament medially; tumor extended into the parapeduncular space with an intimate spatial relationship with the oculomotor nerve and posterior communicating artery. The lateral compartment breakthrough was limited by the anterior petroclinoidal ligament superiorly and ophthalmic nerve inferiorly; tumor extended into the middle fossa, displacing the trochlear nerve and inferolateral trunk to reach the medial temporal lobe. The posterior compartment breakthrough delineated by the Gruber ligament, petrosal process of the sphenoid bone, and petrous apex inferiorly, posterior petroclinoidal ligament superiorly, and dorsum sellae medially; tumor displaced or encased the abducens nerve and inferior hypophyseal artery and compressed the cerebral peduncle.CONCLUSION: The superior lateral and posterior components of the CS are potential routes for invasion by PAs. Better identification of CS breakthrough patterns is crucial for achieving higher gross total resection and remission rates.
View details for DOI 10.1227/ons.0000000000000291
View details for PubMedID 35838451
Ideal trajectory for frontal ventriculostomy: Radiological study and anatomical study.
Clinical neurology and neurosurgery
2022; 217: 107264
OBJECTIVE: Several techniques have been described to improve the accuracy of the freehand procedure for frontal ventriculostomy and reduce complications due to suboptimal placement or misplacement of the catheter tip. To date, none of the available studies have found a reliable, low cost and consistent technique. We aimed to provide a standardized protocol for freehand frontal ventriculostomy.METHODS: In the first part of the radiological study, 125 CT scans were used to measure the length of the catheter using 2 right-sided entry points. In the second part, a grid of 24 entry points on the frontal bone was used in 50 CT scans to record the distance from the cranial surface to the Foramen of Monro (FM). Ventriculostomy was performed on six cadaveric heads using a grid of 9 entry points, comparing a 5ml syringe with the freehand technique to reach the target.RESULTS: The first part of the radiological study showed a length from the cranial surface to the FM was overall 67,38±1,03mm. For the second part, the mean length of the 24 selected points was 68,54±2,73mm without statistical difference. In the anatomical study, the FM was reached 8 times (14.8%) with the syringe vs 31 times (57.4%) with the freehand technique, and the ventricles 43 (79.6%) vs 37 (68.5%). The mean lengths from the skull to the FM were 71.33±4.21mm.CONCLUSIONS: In this study, we showed the optimal length of a frontal ventricular catheter. We have also demonstrated that the portion of the frontal bone above the superior temporal lines matches a sphere in which the center is the FM.
View details for DOI 10.1016/j.clineuro.2022.107264
View details for PubMedID 35526512
Endoscopic Endonasal Approach for Suprasellar Mature Teratoma in Growing Teratoma Syndrome: 2-Dimensional Operative Video.
Operative neurosurgery (Hagerstown, Md.)
Intracranial growing teratoma syndrome is a rare phenomenon characterized by enlargement of a germ cell tumor during or after adjuvant therapy despite normalization of tumor markers.1,2 It has been suggested that chemotherapy acts on the nonteratomatous components or induces differentiation of the immature germ cells to mature teratomatous phenotype.3 An 8-year-old boy presented with headache, emesis, and blurry vision. Neuroimaging revealed hydrocephalus with multiple central nervous system masses: pineal gland, suprasellar region, and spine (T8). Elevated serum and cerebrospinal fluid levels of alpha-fetoprotein and beta-human chorionic gonadotropin were found. A ventriculoperitoneal shunt was placed. Despite chemotherapy and decreasing tumor markers, the pineal mass rapidly enlarged, and the patient became somnolent. He underwent microsurgical resection with the diagnosis of mixed germ cell tumor. During his second chemotherapy cycle, the patient endorsed worsening vision and panhypopituitarism. Imaging demonstrated enlargement and honeycomb appearance of the suprasellar mass. The patient and family consented to the procedure, and an endoscopic endonasal approach was performed to access the retroinfundibular region. Removal of the nonfunctional pituitary gland and dorsum sellae was performed. Careful dissection of the tumor from the optic apparatus, hypothalamus, and perforating arteries allowed total resection. Reconstruction with fascia lata and nasoseptal flap was performed. Mature teratoma was found histologically. Postoperative course was complicated by flap hemorrhage resolved by surgical revision. Postoperative imaging showed complete resection. The patient was discharged without other complications and was making excellent recovery. To the best of our knowledge, this is the first reported case of hypothalamic intracranial growing teratoma syndrome successfully treated using an endoscopic endonasal approach.
View details for DOI 10.1227/ons.0000000000000166
View details for PubMedID 35383719
Microsurgical anatomy and the importance of the petrosal process of the sphenoid bone in endonasal surgery.
Journal of neurosurgery
OBJECTIVE: The petrosal process of the sphenoid bone (PPsb) is a relevant skull base osseous prominence present bilaterally that can be used as a key surgical landmark, especially for identifying the abducens nerve. The authors investigated the surgical anatomy of the PPsb, its relationship with adjacent neurovascular structures, and its practical application in endoscopic endonasal surgery.METHODS: Twenty-one dried skulls were used to analyze the osseous anatomy of the PPsb. A total of 16 fixed silicone-injected postmortem heads were used to expose the PPsb through both endonasal and transcranial approaches. Dimensions and distances of the PPsb from the foramen lacerum (inferiorly) and top of the posterior clinoid process (PCP; superiorly) were measured. Moreover, anatomical variations and the relationship of the PPsb with the surrounding crucial structures were recorded. Three representative cases were selected to illustrate the clinical applications of the findings.RESULTS: The PPsb presented as a triangular bony prominence, with its base medially adjacent to the dorsum sellae and its apex pointing posterolaterally toward the petrous apex. The mean width of the PPsb was 3.5 ± 1 mm, and the mean distances from the PPsb to the foramen lacerum and the PCP were 5 ± 1 and 11 ± 2.5 mm, respectively. The PPsb is anterior to the petroclival venous confluence, superomedial to the inferior petrosal sinus, and inferomedial to the superior petrosal sinus; constitutes the inferomedial limit of the cavernous sinus; and delimits the upper limit of the paraclival internal carotid artery (ICA) before the artery enters the cavernous sinus. The PPsb is anterior and medial to and below the sixth cranial nerve, forming the floor of Dorello's canal. During surgery, gentle mobilization of the paraclival ICA reveals the petrosal process, serving as an accurate landmark for the location of the abducens nerve.CONCLUSIONS: This investigation revealed details of the microsurgical anatomy of the PPsb, its anatomical relationships, and its application as a surgical landmark for identifying the abducens nerve. This novel landmark may help in minimizing the risk of abducens nerve injury during transclival approaches, which extend laterally toward the petrous apex and cavernous sinus region.
View details for DOI 10.3171/2021.12.JNS212024
View details for PubMedID 35276642
Anatomic Considerations in Endoscopic Pituitary Surgery.
Otolaryngologic clinics of North America
The pituitary gland is a small gland at the base of the skull controlling many physiologic processes through its regulation of primary endocrine glands. Pathologies of the pituitary gland and sellar space are wide ranging and most commonly include pituitary adenomas but can also encompass pituitary hyperplasia, other benign nonadenomatous tumors, cysts, and primary and metastatic malignancy. At present, the endoscopic approach has been established as a safe and effective approach to surgical management of pituitary pathology. A detailed understanding of the sella and parasellar anatomy from an endoscopic approach is imperative to performing safe endoscopic surgery in this area.
View details for DOI 10.1016/j.otc.2021.12.014
View details for PubMedID 35256171
Microsurgical anatomy of the dorsal clinoidal space: implications for endoscopic endonasal parasellar surgery.
Journal of neurosurgery
OBJECTIVE: The clinoidal venous space dorsal to the internal carotid artery (ICA) has not been well studied given its inaccessibility due to obstruction by the ICA during transcranial surgery. The evolution of endoscopic endonasal surgery has provided a new perspective into the clinoidal space and a new route for paraclinoidal lesions. Understanding the dorsal clinoidal space (DCS) is vital in planning and performing endoscopic endonasal surgery in the parasellar region. A detailed and precise description of the DCS from the endonasal perspective has not yet been provided. The authors' goal in this study was to delineate the microsurgical anatomy of the DCS from an endoscopic endonasal perspective, emphasizing its surgical implications when treating invasive pituitary adenomas and other parasellar lesions.METHODS: An endoscopic endonasal transsellar approach was performed in 15 silicone-injected postmortem heads. Afterward, the sellar region was dissected through a transcranial approach using magnification *3 to *40 microscopy. The osseous, dural, and arterial relationships of the DCS and its architecture were investigated. The DCS's length, width, and depth were measured and its anatomical variations recorded.RESULTS: The DCS was identified in 90% of the specimens, and in most cases, its shape was a narrow rectangular pyramid, with its base oriented toward the sphenoid sinus and its apex toward the posterior clinoid process. It is delimited superiorly by the distal ring, inferiorly by the medial aspect of the proximal dural ring or caroticoclinoid ligament, laterally by the clinoidal ICA, and medially by the superior continuation of the medial wall of the cavernous sinus. The width, height, and length of the DCS were 4 ± 1, 4.5 ± 1.5, and 7 ± 2 mm, respectively. A fenestrated caroticoclinoid ligament is a potential route for tumor invasion from the cavernous sinus into the DCS.CONCLUSIONS: This report provides important anatomical descriptions of the DCS from endoscopic endonasal and transcranial perspectives that may facilitate the space's safe exposure for the removal of invasive adenomas, increasing total resection rates and minimizing the risk of injury to neurovascular structures.
View details for DOI 10.3171/2021.12.JNS211974
View details for PubMedID 35120312
Microsurgical Anatomy of the Dorsal Clinoidal Space: Implications for Endoscopic Endonasal Parasellar Surgery Abstracts
JOURNAL OF NEUROLOGICAL SURGERY PART B-SKULL BASE
View details for Web of Science ID 000762759700001
Microvascular anatomy of the medial temporal region.
Journal of neurosurgery
OBJECTIVE: The authors investigated the microvascular anatomy of the hippocampus and its implications for medial temporal tumor surgery. They aimed to reveal the anatomical variability of the arterial supply and venous drainage of the hippocampus, emphasizing its clinical implications for the removal of associated tumors.METHODS: Forty-seven silicon-injected cerebral hemispheres were examined using microscopy. The origin, course, irrigation territory, spatial relationships, and anastomosis of the hippocampal arteries and veins were investigated. Illustrative cases of hippocampectomy for medial temporal tumor surgery are also provided.RESULTS: The hippocampal arteries can be divided into 3 segments, the anterior (AHA), middle (MHA), and posterior (PHA) hippocampal artery complexes, which correspond to irrigation of the hippocampal head, body, and tail, respectively. The uncal hippocampal and anterior hippocampal-parahippocampal arteries contribute to the AHA complex, the posterior hippocampal-parahippocampal arteries serve as the MHA complex, and the PHA and splenial artery compose the PHA complex. Rich anastomoses between hippocampal arteries were observed, and in 11 (23%) hemispheres, anastomoses between each segment formed a complete vascular arcade at the hippocampal sulcus. Three veins were involved in hippocampal drainage-the anterior hippocampal, anterior longitudinal hippocampal, and posterior longitudinal hippocampal veins-which drain the hippocampal head, body, and tail, respectively, into the basal and internal cerebral veins.CONCLUSIONS: An understanding of the vascular variability and network of the hippocampus is essential for medial temporal tumor surgery via anterior temporal lobectomy with amygdalohippocampectomy and transsylvian selective amygdalohippocampectomy. Stereotactic procedures in this region should also consider the anatomy of the vascular arcade at the hippocampal sulcus.
View details for DOI 10.3171/2021.9.JNS21390
View details for PubMedID 34952521
Microsurgical anatomy of the lateral posterior choroidal artery: implications for intraventricular surgery involving the choroid plexus.
Journal of neurosurgery
OBJECTIVE: The lateral posterior choroidal artery (LPChA) should be a major surgical consideration in the microsurgical management of lateral ventricular tumors. Here the authors aim to delineate the microsurgical anatomy of the LPChA by using anatomical microdissections. They describe the trajectory, segments, and variations of the LPChA and discuss the surgical implications when approaching the choroid plexus using different routes.METHODS: Twelve colored silicone-injected, lightly fixed, postmortem human head specimens were prepared for dissection. The origin, diameter, trunk, course, segment, length, spatial relationships, and anastomosis of the LPChA were investigated. The surgical landmarks of 4 different approaches to the LPChA were also examined thoroughly.RESULTS: The LPChA was present in 23 hemispheres (96%), and in 14 (61%) it originated from the posterior segment of the P2 (i.e., P2P); most commonly (61%) the LPChA had 2 trunks, and in 17 hemispheres (74%) it had a C-shaped trajectory. According to its course, the authors divided the LPChA into 3 segments: 1) cisternal, from PCA to choroidal fissure (length 10.6 ± 2.5 mm); 2) forniceal, starting at the choroidal fissure, 8.2 ± 5.7 mm posterior to the inferior choroidal point, and terminating at the posterior level of the choroidal fissure (length 28.7 ± 6.8 mm); and 3) pulvinar, starting at the posterior choroidal fissure and terminating in the pulvinar (length 5.9 ± 2.2 mm). The LPChA was divided into 3 patterns according to its entrance into the choroidal fissure: A (anterior) 78%; B (posterior) 13%; and C (mixed) 9%. The transsylvian trans-limen insulae approach provided the best exposure for cisternal and proximal forniceal segments; the lateral transtemporal approach facilitated a more direct approach to the forniceal segment, including cases with posterior entrance; the transparietal transcortical and contralateral posterior interhemispheric transfalcine transprecuneus approaches provided direct access to the pulvinar segment of the LPChA and to the posterior forniceal segment, including cases with posterior choroidal entrance.CONCLUSIONS: The LPChA typically runs in the medial border of the choroid plexus, which may facilitate its recognition during surgery. The distance between the AChA at the inferior choroidal point and the LPChA is a valuable reference during surgery, but there are cases of posterior choroidal entrance. Most frequently, there are 2 or more LPChA trunks, which makes possible the sacrifice of one trunk feeding the tumor while preserving the other that provides supply to relevant structures. The intraventricular approaches can be selected based on the tumor location and the LPChA anatomy.
View details for DOI 10.3171/2020.8.JNS202230
View details for PubMedID 33836500
Radiological outcomes for endovascular treatment of posterior communicating artery aneurysms: a retrospective multicenter study of the occlusion rate.
Journal of integrative neuroscience
2021; 20 (4): 919-931
Although several innovations in techniques and implantable devices were reported over the last decades, a consensus on the best endovascular treatment for intracranial aneurysms originating from the posterior communicating artery is still missing. This work investigates radiological outcomes of different endovascular techniques for posterior communicating artery aneurysms treatment in a retrospective multi-centric cohort. We included patients endovascularly treated for posterior communicating artery aneurysms from 2015 through 2020 in six tertiary referral hospitals. We evaluated the relationship between patients and aneurysms characteristics, baseline neurological status, radiological outcomes, and the different endovascular techniques. Overall, 250 patients were included in this study. Simple coiling was the most frequent treatment in 171 patients (68%), followed by flow-diverter stenting in 32 cases (13%). Complete occlusion was reported in 163 patients (65%), near-complete occlusion in 43 (17%), and incomplete occlusion in 44 (18%). Radiological follow-up was available for 247 (98%) patients. The occlusion rate was stable in 149 (60%), improved in 49 (19%), and worsened in 51 (21%). No significant difference in exclusion rate was seen between ruptured and unruptured aneurysms at the last follow-up (p = 0.4). Posterior communicating artery thrombosis was reported in 25 patients (9%), transient ischemic attack in 6 (2%), and in 38 patients (15%), subsequent procedures were needed due to incomplete occlusion or reperfusion. Endovascular strategies for posterior communicating artery aneurysms represent effective and relatively safe treatments. Simple coiling provides a higher immediate occlusion rate, although recanalization has been frequently reported, conversely, flow-diversion devices provide good long-term radiological outcomes.
View details for DOI 10.31083/j.jin2004093
View details for PubMedID 34997715
The Smith-Robinson Approach to the Subaxial Cervical Spine: A Stepwise Microsurgical Technique Using Volumetric Models From Anatomic Dissections.
Operative neurosurgery (Hagerstown, Md.)
The Smith-Robinson1 approach (SRA) is the most widely used route to access the anterior cervical spine. Although several authors have described this approach, there is a lack of the stepwise anatomic description of this operative technique. With the advent of new technologies in neuroanatomy education, such as volumetric models (VMs), the understanding of the spatial relation of the different neurovascular structures can be simplified.To describe the anatomy of the SRA through the creation of VMs of anatomic dissections.A total of 4 postmortem heads and a cervical replica were used to perform and record the SRA approach to the C4-C5 level. The most relevant steps and anatomy of the SRA were recorded using photogrammetry to construct VM.The SRA was divided into 6 major steps: positioning, incision of the skin, platysma, and muscle dissection with and without submandibular gland eversion and after microdiscectomy with cage positioning. Anatomic model of the cervical spine and anterior neck multilayer dissection was also integrated to improve the spatial relation of the different structures.In this study, we review the different steps of the classic SRA and its variations to different cervical levels. The VMs presented allow clear visualization of the 360-degree anatomy of this approach. This new way of representing surgical anatomy can be valuable resources for education and surgical planning.
View details for DOI 10.1093/ons/opaa265
View details for PubMedID 32864701