Transsylvian selective amygdalohippocampectomy for treatment of medial temporal lobe epilepsy: Surgical technique and operative nuances to avoid complications

Background: A number of different surgical techniques are effective for treatment of drug-resistant medial temporal lobe epilepsy. Of these, transsylvian selective amygdalohippocampectomy (SA), which was originally developed to maximize temporal lobe preservation, is arguably the most technically demanding to perform. Recent studies have suggested that SA may result in better neuropsychological outcomes with similar postoperative seizure control as standard anterior temporal lobectomy, which involves removal of the lateral temporal neocortex. Methods: In this article, the authors describe technical nuances to improve the safety of SA. Results: Wide sylvian fissure opening and use of neuronavigation allows an adequate exposure of the amygdala and hippocampus through a corticotomy within the inferior insular sulcus. Avoidance of rigid retractors and careful manipulation and mobilization of middle cerebral vessels will minimize ischemic complications. Identification of important landmarks during amygdalohippocampectomy, such as the medial edge of the tentorium and the third nerve within the intact arachnoid membranes covering the brainstem, further avoids operator disorientation. Conclusion: SA is a safe technique for resection of medial temporal lobe epileptogenic foci leading to drug-resistant medial temporal lobe epilepsy

External cortical landmarks and measurements for the temporal horn: Anatomic study with application to surgery of the temporal lobe

BACKGROUND: The location of the temporal horn is important to neurosurgeons during procedures such as amygdalohippocampectomy and intraventricular electrode placement for temporal lobe seizure monitoring. However, sometimes the temporal horn is difficult to localize, especially without neuronavigation. The authors aimed to better localize this structure using superficial anatomic landmarks. METHODS: Twenty-two brain halves were dissected from the midline, and the fornix identified and followed toward the left and right temporal horns. Once the temporal horn was isolated from a mesial approach, 6-cm long needles were placed into its anterior and posterior walls of the temporal horn and passed laterally from the axial plane to the cortical surface. Pin exit sites were marked externally and measurements taken between the outer temporal lobe cortex and the underlying temporal horn. RESULTS: No statistical differences were noted between left and right sides. The temporal horn was generally directed anteroinferiorly and best marked externally by the inferior temporal sulcus. The mean length of the temporal horn was 4.4 cm. Mean distance from anterior temporal tip to anterior wall of the temporal horn was 3.3 cm. The mean distance from the anterior temporal tip to the posterior wall of the temporal horn was 7 cm. The anterior wall of the temporal horn was a mean of 3 mm superior to the inferior temporal sulcus. The posterior wall was a mean of 1.2 cm superior to the inferior temporal sulcus. CONCLUSIONS: These landmarks and measurements may help neurosurgeons better localize this part of the lateral ventricular system

The Intramuscular Course of the Greater Occipital Nerve: Novel Findings with Potential Implications for Operative Interventions and Occipital Neuralgia

Background: A better understanding of the etiologies of occipital neuralgia would help the clinician treat patients with this debilitating condition. Since few studies have examined the muscular course of the greater occipital nerve (GON), this study was performed. Methods: Thirty adult cadaveric sides underwent dissection of the posterior occiput with special attention to the intramuscular course of the GON. Nerves were typed based on their muscular course. Results: The GON traveled through the trapezius (type I; n = 5, 16.7%) or its aponeurosis (type II; n = 15, 83.3%) to become subcutaneous. Variations in the subtrapezius muscular course were found in 10 (33%) sides. In two (6.7%) sides, the GON traveled through the lower edge of the inferior capitis oblique muscle (subtype a). On five (16.7%) sides, the GON coursed through a tendinous band of the semispinalis capitis, not through its muscular fibers (subtype b). On three (10%) sides the GON bypassed the semispinalis capitis muscle to travel between its most medial fibers and the nuchal ligament (subtype c). For subtypes, eight were type II courses (through the aponeurosis of the trapezius), and two were type I courses (through the trapezius muscle). The authors identified two type IIa courses, four type IIb courses, and two type IIc courses. Type I courses included one type Ib and one type Ic courses. Conclusions: Variations in the muscular course of the GON were common. Future studies correlating these findings with the anatomy in patients with occipital neuralgia may elucidate nerve courses vulnerable to nerve compression. This enhanced classification scheme describes the morphology in this region and allows more specific communications about GON variations

A new segment of the trochlear nerve: cadaveric study with application to skull base surgery

Objectives The trochlear nerve is important to preserve during approaches to the skull base. Traditionally, this nerve has been divided into cisternal, cavernous, and orbital segments. However, the authors anecdotally observed an additional segment during routine cadaveric dissections. Therefore, they performed this study to better elucidate this anatomy. Design Twenty latex-injected cadaveric sides (10 adult cadavers) were dissected with the aid of an operating microscope. Standard microdissection techniques were used to examine the course of the distal cisternal and precavernous segments of the trochlear nerve. Setting Cadaver laboratory. Main Outcome Measures Measurements were made using a microcaliper. Digital images were made of the dissections. Results The authors identified a previously undescribed segment of the trochlear nerve in all specimens. This part of the nerve coursed between the entrance of the trochlear nerve into the posterior corner of the oculomotor trigone to the posterior wall of the cavernous sinus. This segment of trochlear nerve was, on average, 4 mm in length. Conclusions The authors have identified a new segment of the trochlear nerve not previously described. They propose that this be referred to as the trigonal segment. Knowledge of the microanatomy of the trochlear nerve is useful to skull base surgeons

Neural Connections between the Nervus Intermedius and the Facial and Vestibulocochlear Nerves in the Cerebellopontine Angle: An Anatomic Study

Purpose Unexpected clinical outcomes following transection of single nerves of the internal acoustic meatus have been reported. Therefore, this study aimed to investigate interneural connections between the nervus intermedius and the adjacent nerves in the cerebellopontine angle. Methods On 100 cadaveric sides, dissections were made of the facial/vestibulocochlear complex in the cerebellopontine angle with special attention to the nervus intermedius and potential connections between this nerve and the adjacent facial or vestibulocochlear nerves. Results A nervus intermedius was identified on all but ten sides. Histologically confirmed neural connections were found between the nervus intermedius and either the facial or vestibulocochlear nerves on 34 % of sides. The mean diameter of these small interconnecting nerves was 0.1 mm. The fiber orientation of these nerves was usually oblique (anteromedial or posterolateral) in nature, but 13 connections traveled anteroposteriorly. Connecting fibers were single on 81 % of sides, doubled on 16 %, and tripled on 3 %, six sides had connections both with the facial nerve anteriorly and the vestibular nerves posteriorly. On 6.5 % of sides, a connection was between the nervus intermedius and cochlear nerve. For vestibular nerve connections with the nervus intermedius, 76 % were with the superior vestibular nerve and 24 % with the inferior vestibular nerve. Conclusions Knowledge of the possible neural interconnections found between the nervus intermedius and surrounding nerves may prove useful to surgeons who operate in these regions so that inadvertent traction or transection is avoided. Additionally, unanticipated clinical presentations and exams following surgery may be due to such neural interconnections

DOPRINOSI NEUROKIRURGIJI SAMUELA D. GROSSA

One of the most famous American Surgeons of the early 1800s was Samuel David Gross (1805-1884). His mastery of surgery was immortalized in Thomas Eakins’ 1875 painting of Gross titled The Gross Clinic. Gross was a prolific surgeon and one of his textbooks, a System of Surgery, went through 6 editions. Not known to many is the fact that this book also covered neurosurgical diseases and techniques. Gross was a skilled surgeon and able writer. His textbooks on surgery were well received in his day. Moreover, he should be considered an early pioneer of neurosurgery as his System of Surgery is filled with neurosurgical diagnoses and neurosurgical techniques.Samuel David Gross (1805.–1884.) bio je jedan od najpoznatijih američkih kirurga prvog dijela 19. stoljeća. Njegova kirurška vještina stekla je besmrtnost u Grossovoj slici Thomasa Eakinsa iz 1875. naslovljenoj Grossova klinika (The Gross Clinic). Gross je bio plodan kirurg i jedan je od njegovih udžbenika, Sustav kirurgije (System of Surgery), doživio 6 izdanja. Ono što je malo poznato jest činjenica da je ta knjiga također pokrila neurokirurške bolesti i tehnike. Gross je bio vješt kirurg i sposoban pisac. Njegovi udžbenici o kirurgiji bili su dobro primljeni u njegovo vrijeme. Štoviše, trebao bi se smatrati ranim pionirom neurokirurgije, budući da je njegov Sustav kirurgije ispunjen neurokirurškim dijagnozama i neurokirurškim tehnikama

Choroid Plexus of the Fourth Ventricle: Review and Anatomic Study Highlighting Anatomical Variations

Relatively few studies have been performed that analyze the morphology of the choroid plexus of the fourth ventricle. Due to the importance of this tissue as a landmark on imaging and during surgical intervention of the fourth ventricle, the authors performed a cadaveric study to better characterize this important structure. The choroid plexus of the fourth ventricle of 60 formalin fixed adult human brains was examined and measured. The horizontal distance from the midline to the lateral most point of the protruding tip of the horizontal limbs was measured. In the majority of the 60 brain specimens, right and left horizontal limbs of the choroid plexus were seen extending from the midline and protruding out of their respective lateral apertures of the fourth ventricle and into the subarachnoid space. However, on 3.3% of sides, there was absence of an extension into the foramen of Luschka and in one specimen, this lack of extension into the foramen of Luschka was bilateral. On two sides, there was discontinuity between the midline choroid plexus and the tuft of choroid just outside the foramen of Luschka. For specimens in which the choroid plexus did protrude through the foramen of Luschka (96.7%), these tufts were located anterior to the flocculus and inferolateral to the facial/vestibulocochlear nerve complex and posterosuperior to the glossopharyngeal/vagal/accessory complex. A thorough understanding of the normal and variant anatomy of the fourth ventricular choroid plexus is necessary for those who operate in, or interpret imaging of, this region

The Current Understanding of MicroRNA\u27s Therapeutic, Diagnostic, and Prognostic Role in Chordomas: A Review of the Literature.

Chordomas are primary low-grade bone tumors derived from the embryonic notochord that make up less than 5% of all osseous malignancies and commonly affect the spine at its vertebral body and at its two ends i.e., skull base and the sacrum. Although histologically defined to be low-grade, chordoma is locally destructive, metastatic, and has a serious recurrence rate, which all contribute to the dismal median survival rate of six years. Its locally destructive nature places the adjacent vital neurovascular structures at risk, making an en-bloc resection a challenge. This tumor is also known to show high resistance to currently available chemoradiotherapy, although the benefit of proton beam therapy for skull base chordoma has been demonstrated. There is an additional need to focus our attention on investigating the molecular biology of this chemoradiotherapy-resistant tumor to develop a more targeted therapy, which has additional diagnostic and prognostic values. In this paper, we discuss the therapeutic, diagnostic, and prognostic role of microRNAs (miRNAs) in chordomas

Emerging Cellular Therapies for Glioblastoma Multiforme.

Glioblastoma multiforme (GBM) is the most common type of malignant primary brain cancer in adults. It is composed of highly malignant cells that display metastatic and angiogenic characteristics, making it resistant to current first-line chemotherapy with temozolomide, an alkylating agent. Despite many years of research, GBM remains poorly responsive to multiple available therapies, giving GBM patients, who receive the conventional combination of chemoradiotherapies and surgical resection, a dismal prognosis. There is growing evidence that the conventional systemic chemotherapeutic agents for GBM are ineffective in improving the disease progression. We aim to explore the emerging cellular therapies which may play a significant role in treating GBM