Neurosurgery made easy

- The upward gaze Centre is close to the superior colliculus , while the downward gaze centre is close to the inferior colliculus. so that ,...
vertical gaze palsy = midbrain lesion
- the horizontal gaze is controlled by the frontal lobe and the pons . so that ,...
Horizontal gaze palsy = frontal lobe / pons lesion.

The insula is a challenging structure to reach surgically because of its complex anatomy and the overlying highly eloquent cortices and white matter tracts, as well as critical vascular structures.

Above, the topography and operative vascular relationships for insular tumors are demonstrated. Note how the lateral lenticulostriate arteries originate from the M1 segment and represent the medial limit of resection. Short M2 perforators supply the tumor. Long M2 perforators may travel through the tumor, but most likely supply corona radiata (especially the ones travelling toward the central sulcus) and must be preserved. The superior and inferior peri-insular sulci represent the lateral superior and inferior anatomic margins of the resection, and their exposure ensures an adequate Sylvian fissure split so that residual tumor does not hide within the blind spots of the operator.

The insula plays an important role in visceral sensorimotor processing, sympathetic control of cardiovascular tone and somatosensory input. It also participates in pain processing, motor planning, volitional swallowing, and gustatory, auditory, vestibular, emotional, and cognitive functions, including language. Compared with other gliomas, insular gliomas are unique in their presentation and behavior. These tumors usually arise in areas of white matter adjacent to the allocortex or mesocortex. During their initial phases of growth, these tumors frequently respect the neocortices, central nuclei, and ventricles.

When performing percutaneous rhizotomy for trigeminal neuralgia, the needle is advanced to reach an ideal position on the lateral X-ray. Note that the tip of the needle is aimed at the junction of the clivus and petrous bone. This is the most important landmark on the lateral fluoroscopic image and guides the surgeon to reach the foramen ovale. The needle tip is advanced to the bony junction, and upon entering the foramen, should rest between 5-15 mm below the sellar floor.

High grade glioma: GBM
Goal of the surgery in a high grade glioma is maximal safe resection. However there are numerous studies correlating extent of resection with survival benefit. Gross total resection should be the aim.

LGGs tend to be non-enhancing and evidence of punctate calcification and a heterogeneous appearance are consistent with a diagnosis of oligodendroglioma. The 3 most common types of LGGs are oligodendrogliomas, astrocytomas, and oligoastrocytomas.

Sensorimotor mapping can improve resection of intra-axial lesions, most frequently gliomas near or partially infiltrating the sensorimotor cortices and corona radiata. Preoperative evaluation of sensorimotor function is critical. Significant hemiparesis hinders cortical and subcortical mapping; the patient should at least have antigravity movement in the corresponding extremities preoperatively. Also, children under the age of 6 may have decreased cortical excitability. Somatosensory evoked potentials (SSEPs) should be used to identify the central sulcus when motor cortex excitation is not feasible.

Lamina terminalis is dissected to access the anterior third ventricle. However, the subfrontal translamina terminalis approach is a restricted, nonflexible operative corridor that cannot be safely expanded.

Vestibular neurotomy is performed for refractory Meniere’s disease with symptom relief in up to 95% of appropriately selected patients. The retromastoid approach is used for vestibular nerve resection.

The posterior commissure is a white matter fiber tract that crosses midline dorsal to the cerebral aqueduct. Pretectal nuclei send stimuli to the Edinger–Westphal nuclei via the posterior commissure which contributes to the consensual pupillary reflex.

The superior petrosal vein is formed by union of several veins draining the anterior and lateral surfaces of the brainstem and cerebellum. The superior petrosal vein empties into the superior petrosal sinus near the trigeminal nerve.

The posterior commissure is a white matter fiber tract that crosses midline dorsal to the cerebral aqueduct. Pretectal nuclei send stimuli to the Edinger–Westphal nuclei via the posterior commissure which contributes to the consensual pupillary reflex.
PC: Rhotons

Hello folks, its been a long week haven’t shared any updates, will soon start that😊

The corresponding craniotomies used to reach various brainstem lesions are shown. The suboccipital, retrosigmoid, supracerebellar, and orbitozygomatic approaches are favored for most lesions.

Cisternal Anatomy.

Ascending and descending tracts.

The claustrum is a thin sheet of gray matter that lies between the extreme and external capsules. Recent studies reported that the claustrum may have a major role in regulating cortical excitability and is involved in mediating consciousness and attention.

NF1 and NF2.

UMN vs LMN.

Types of Meningioma.

Worth sharing.

Spinal injury scale.