Chih-Hsiang Liao, Chung-Jung Lin, Chun-Fu Lin, Hsin-Yi Huang, Min-Hsiung Chen, Sanford P. C. Hsu and Yang-Hsin Shih
The treatment of paraclinoid aneurysms remains challenging. It is important to determine the exact location of the paraclinoid aneurysm when considering treatment options. The authors herein evaluated the effectiveness of using the optic strut (OS) and tuberculum sellae (TS) as radiographic landmarks for distinguishing between intradural and extradural paraclinoid aneurysms on source images from CT angiography (CTA).
Between January 2010 and September 2013, a total of 49 surgical patients with the preoperative diagnoses of paraclinoid aneurysm and 1 symptomatic cavernous-clinoid aneurysm were retrospectively identified. With the source images from CTA, the OS and the TS were used as landmarks to predict the location of the paraclinoid aneurysm and its relation to the distal dural ring (DDR). The operative findings were examined to confirm the definitive location of the paraclinoid aneurysm. Statistical analysis was performed to determine the diagnostic effectiveness of the landmarks.
Nineteen patients without preoperative CTA were excluded. The remaining 30 patients comprised the current study. The intraoperative findings confirmed 12 intradural, 12 transitional, and 6 extradural paraclinoid aneurysms, the diagnoses of which were significantly related to the type of aneurysm (p < 0.05) but not factors like sex, age, laterality of aneurysm, or relation of the aneurysm to the ophthalmic artery on digital subtraction angiography. To measure agreement with the correct diagnosis, the OS as a reference point was far superior to the TS (Cohen's kappa coefficients 0.462 and 0.138 for the OS and the TS, respectively). For paraclinoid aneurysms of the medial or posterior type, using the base of the OS as a reference point tended to overestimate intradural paraclinoid aneurysms. The receiver operating characteristic curve indicated that if the aneurysmal neck traverses the axial plane 2 mm above the base of the OS, the aneurysm is most likely to grow across the DDR and present as a transitional aneurysm (sensitivity 0.806; specificity 0.792).
High-resolution thin-cut CTA is a fast and crucial tool for diagnosing paraclinoid aneurysms. The OS serves as an effective landmark in CTA source images for distinguishing between intradural and extradural paraclinoid aneurysms. The DDR is supposed to be located 2 mm above the base of the OS in axial planes.
Chih-Hsiang Liao, Jui-To Wang, Chun-Fu Lin, Shao-Ching Chen, Chung-Jung Lin, Sanford P. C. Hsu and Min-Hsiung Chen
Despite the advances in skull base techniques, large petroclival meningiomas (PCMs) still pose a challenge to neurosurgeons. The authors’ objective of this study was to describe a pretemporal trans–Meckel’s cave transtentorial approach for large PCMs and to report the surgical outcomes.
From 2014 to 2017, patients harboring large PCMs (> 3 cm) and undergoing their first resection via this procedure at the authors’ institute were included. In combination with pretemporal transcavernous and anterior transpetrosal approaches, the trans–Meckel’s cave transtentorial route was created. Surgical details are described and a video demonstrating the procedure is included. Retrospective review of the medical records and imaging studies was performed.
A total of 18 patients (6 men and 12 women) were included in this study, with mean age of 53 years. The mean sizes of the preoperative and postoperative PCMs were 4.36 cm × 4.09 cm × 4.13 cm (length × width × height) and 0.83 cm × 1.08 cm × 0.75 cm, respectively. Gross-total removal was performed in 7 patients, near-total removal (> 95%) in 7 patients, and subtotal removal in 4 patients (> 90% in 3 patients and > 85% in 1 patient). There were no surgical deaths or patients with postoperative hemiplegia. Surgical complications included transient cranial nerve (CN) III palsy (all patients, resolved in 3 months), transient CN VI palsy (2 patients), CN IV palsy (3 patients, partial recovery), hydrocephalus (3 patients), and CSF otorrhea (1 patient). Temporal lobe retraction–related neurological deficits were not observed.
A pretemporal trans–Meckel’s cave transtentorial approach offers large surgical exposure and multiple trajectories to the suprasellar, interpeduncular, prepontine, and upper-half clival regions without overt traction, which is mandatory to remove large PCMs. To unlock Meckel’s cave where a large PCM lies abutting the cave, pretemporal transcavernous and anterior transpetrosal approaches are prerequisites to create adequate exposure for the final trans–Meckel’s cave step.
Syu-Jyun Peng, Chien-Chen Chou, Hsiang-Yu Yu, Chien Chen, Der-Jen Yen, Shang-Yeong Kwan, Sanford P. C. Hsu, Chun-Fu Lin, Hsin-Hung Chen and Cheng-Chia Lee
In this study, the authors investigated high-frequency oscillation (HFO) networks during seizures in order to determine how HFOs spread from the focal cerebral cortex and become synchronized across various areas of the brain.
All data were obtained from stereoelectroencephalography (SEEG) signals in patients with drug-resistant temporal lobe epilepsy (TLE). The authors calculated intercontact cross-coefficients between all pairs of contacts to construct HFO networks in 20 seizures that occurred in 5 patients. They then calculated HFO network topology metrics (i.e., network density and component size) after normalizing seizure duration data by dividing each seizure into 10 intervals of equal length (labeled I1–I10).
From the perspective of the dynamic topologies of cortical and subcortical HFO networks, the authors observed a significant increase in network density during intervals I5–I10. A significant increase was also observed in overall energy during intervals I3–I8. The results of subnetwork analysis revealed that the number of components continuously decreased following the onset of seizures, and those results were statistically significant during intervals I3–I10. Furthermore, the majority of nodes were connected to a single dominant component during the propagation of seizures, and the percentage of nodes within the largest component grew significantly until seizure termination.
The consistent topological changes that the authors observed suggest that TLE is affected by common epileptogenic patterns. Indeed, the findings help to elucidate the epileptogenic network that characterizes TLE, which may be of interest to researchers and physicians working to improve treatment modalities for epilepsy, including resection, cortical stimulation, and neuromodulation treatments that are responsive to network topologies.
Xavier T. J. Hsu, Chih-Hsiang Liao, Chun-Fu Lin and Sanford P. C. Hsu
A 57-year-old man presented with acute changes in mental status. Brain CT showed a high-density lesion at the pons. Brain MRA revealed a very slow-flow vascular lesion at the right aspect of the pons, about 3.9 ⋅ 3.0 ⋅ 3.0 cm3, compatible with a pontine cavernous malformation (CM). Gross-total removal was achieved. In this approach, a wider surgical corridor was obtained by opening the Meckel’s cave and cutting the tentorium. For a midline attack point on the pons, additional removal of the posterior clinoid process can meet the goal. In the authors’ opinion, this approach is safe and effective in selected ventrolateral pontine CMs.
The video can be found here: https://youtu.be/moHqEkp5eCA.
Chih-Hsiang Liao, Chun-Fu Lin, Wei-Hsin Wang, Jui-To Wang, Shao-Ching Chen and Sanford P. C. Hsu
A 39-year-old man, who had a history of spinal myxopapillary ependymoma with cerebrospinal seeding status post twice operations and radiation therapy, presented with aggravating headaches, diplopia, dysphagia, and unsteady gait for 2 weeks. The brain MRI revealed a parenchymal lesion at the left aspect of the pons, about 2.8 × 2.3 × 3.2 cm3. The patient underwent a pretemporal transcavernous transtentorial approach for tumor removal. The pathological report showed an anaplastic astrocytoma. In this approach, a wider surgical corridor was obtained by opening the Meckel’s cave and cutting the tentorium, via which a safe entry point into the pons could be determined with neuromonitoring. In the authors’ opinion, this approach is safe and effective in selected ventrolateral pontine gliomas.
The video can be found here: https://youtu.be/sUt-9QFGgCI.