SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Oculomotor nerve

168

Aims : To derive a reliable estimate of the frequency of pupillary involvement and to study the patterns and course of anisocoria in conjunction with ophthalmoplegia in diabetes-associated oculomotor nerve palsy. Materials and Methods: In this prospective analytical study, standardized enrolment criteria were employed to identify 35 consecutive patients with diabetes-associated oculomotor nerve palsy who were subjected to a comprehensive ocular examination. Standardized methods were used to evaluate pupil size, shape, and reflexes. The degree of anisocoria, if present and the degree of ophthalmoplegia was recorded at each visit. Results: Pupillary involvement was found to be present in 25.7% of the total number of subjects with diabetic oculomotor nerve palsy. The measure of anisocoria was < 2 mm, and pupil was variably reactive at least to some extent in all cases with pupillary involvement. Majority of patients in both the pupil-involved and pupil-spared group showed a regressive pattern of ophthalmoplegia. Ophthalmoplegia reversed much earlier and more significantly when compared to anisocoria. Conclusions: Pupillary involvement in diabetes-associated oculomotor nerve palsy occurs in about 1/4 th of all cases. Certain characteristics of the pupil help us to differentiate an ischemic insult from an aneurysmal injury to the 3 rd nerve. Ophthalmoplegia resolves much earlier than anisocoria in diabetic oculomotor nerve palsies.

Concepts: Eye, Cranial nerves, Oculomotor nerve, Pupil, Oculomotor nerve palsy, Edinger-Westphal nucleus, Anisocoria, Mydriasis

28

Interdural epidermoid cysts of the cavernous sinus originate within the lateral dural wall of the cavernous sinus. Few data are available on the diagnosis and treatment of these tumors. In this study, four patients with interdural epidermoid cyst of the cavernous sinus are reported and data from six patients reported in the English literature are summarized. Trigeminal nerve dysfunction, ophthalmoplegia, and headache were the common symptoms and signs. MRI was the primary diagnostic tool. Contrast enhanced MRI showed slight or strong rim enhancement in six of the 10 patients. All patients were treated by surgical resection using frontotemporal or pterional craniotomy via the intradural or interdural approach. Total removal was achieved in three of the four patients, and four of 10 patients in the whole series. Postoperative neurological function improved in all patients. During follow-up, there were three known clinical recurrences in the total group, but no recurrence in the four patients treated at Qilu Hospital of Shandong University. The findings suggest that aggressive surgical management is associated with good results and with low complication and recurrence rates, but radical resection at the risk of impairing the cranial nerves is not recommended.

Concepts: Cranial nerves, Nerve, Mandibular nerve, Oculomotor nerve, Trochlear nerve, Trigeminal nerve, Maxillary nerve, Abducens nerve

28

Ophthalmoplegic migraine is a rare disorder characterized by childhood-onset ophthalmoplegia and migraine headaches. The third cranial nerve is commonly involved, while involvement of the sixth and fourth cranial nerves is uncommon. We present the case study of a 15-year-old female teenager whose condition was diagnosed with ophthalmoplegic migraine when she was 9 years old and since then has experienced multiple and recurrent attacks. Since the diagnosis, she has exhibited a persistent right-eye mydriasis, despite resolution of migrainous episodes. Pupillary involvement in ophthalmoplegic migraine is the rule in children, with total recovery in the majority of cases. We will discuss some aspects related to the eventual association between this entity and other comorbidities, such as Adie tonic pupil, emphasizing the fact that the underlying mechanisms of this residual mydriasis are not fully understood.

Concepts: Cranial nerves, Nerve, Oculomotor nerve, Neurological disorders, Pupil, Anisocoria, Mydriasis, Miosis

28

Aberrant regeneration of a third nerve palsy (oculomotor synkinesis) excludes an ischaemic cause and in the absence of relevant trauma strongly suggests a compressive aetiology. A scan is mandatory in such cases. We describe the case of a 52-year-old woman who presented with complete pupil-involving third nerve palsy from a posterior communicating artery aneurysm, who later developed widespread aberrant regeneration of pupil, eyelid and third nerve territory rectus muscles.

Concepts: Muscle, Posterior communicating artery, Cerebral aneurysm, Case, Oculomotor nerve, In the Absence of Truth, Oculomotor nerve palsy

4

OBJECT Automated eye movement tracking may provide clues to nervous system function at many levels. Spatial calibration of the eye tracking device requires the subject to have relatively intact ocular motility that implies function of cranial nerves (CNs) III (oculomotor), IV (trochlear), and VI (abducent) and their associated nuclei, along with the multiple regions of the brain imparting cognition and volition. The authors have developed a technique for eye tracking that uses temporal rather than spatial calibration, enabling detection of impaired ability to move the pupil relative to normal (neurologically healthy) control volunteers. This work was performed to demonstrate that this technique may detect CN palsies related to brain compression and to provide insight into how the technique may be of value for evaluating neuropathological conditions associated with CN palsy, such as hydrocephalus or acute mass effect. METHODS The authors recorded subjects' eye movements by using an Eyelink 1000 eye tracker sampling at 500 Hz over 200 seconds while the subject viewed a music video playing inside an aperture on a computer monitor. The aperture moved in a rectangular pattern over a fixed time period. This technique was used to assess ocular motility in 157 neurologically healthy control subjects and 12 patients with either clinical CN III or VI palsy confirmed by neuro-ophthalmological examination, or surgically treatable pathological conditions potentially impacting these nerves. The authors compared the ratio of vertical to horizontal eye movement (height/width defined as aspect ratio) in normal and test subjects. RESULTS In 157 normal controls, the aspect ratio (height/width) for the left eye had a mean value ± SD of 1.0117 ± 0.0706. For the right eye, the aspect ratio had a mean of 1.0077 ± 0.0679 in these 157 subjects. There was no difference between sexes or ages. A patient with known CN VI palsy had a significantly increased aspect ratio (1.39), whereas 2 patients with known CN III palsy had significantly decreased ratios of 0.19 and 0.06, respectively. Three patients with surgically treatable pathological conditions impacting CN VI, such as infratentorial mass effect or hydrocephalus, had significantly increased ratios (1.84, 1.44, and 1.34, respectively) relative to normal controls, and 6 patients with supratentorial mass effect had significantly decreased ratios (0.27, 0.53, 0.62, 0.45, 0.49, and 0.41, respectively). These alterations in eye tracking all reverted to normal ranges after surgical treatment of underlying pathological conditions in these 9 neurosurgical cases. CONCLUSIONS This proof of concept series of cases suggests that the use of eye tracking to detect CN palsy while the patient watches television or its equivalent represents a new capacity for this technology. It may provide a new tool for the assessment of multiple CNS functions that can potentially be useful in the assessment of awake patients with elevated intracranial pressure from hydrocephalus or trauma.

Concepts: Nervous system, Intracranial pressure, Ratio, Eye, Cranial nerves, Aspect ratio, Oculomotor nerve, Abducens nerve

2

OBJECT Brainstem surgery remains a challenge for the neurosurgeon despite recent improvements in neuroimaging, microsurgical techniques, and electrophysiological monitoring. A detailed knowledge of the microsurgical anatomy of the brainstem surface and its internal architecture is mandatory to plan appropriate approaches to the brainstem, to choose the safest point of entry, and to avoid potential surgical complications. METHODS An extensive review of the literature was performed regarding the brainstem surgical approaches, and their correlations with the pertinent anatomy were studied and illustrated through dissection of human brainstems properly fixed with 10% formalin. The specimens were dissected using the fiber dissection technique, under ×6 to ×40 magnification. 3D stereoscopic photographs were obtained (anaglyphic 3D) for better illustration of this study. RESULTS The main surgical landmarks and their relationship with the cerebellum and vascular structures were identified on the surface of the brainstem. The arrangements of the white matter (ascending and descending pathways as well as the cerebellar peduncles) were demonstrated on each part of the brainstem (midbrain, pons, and medulla oblongata), with emphasis on their relationships with the surface. The gray matter, constituted mainly by nuclei of the cranial nerves, was also studied and illustrated. CONCLUSIONS The objective of this article is to review the microsurgical anatomy and the surgical approaches pertinent to the brainstem, providing a framework of its external and internal architecture to guide the neurosurgeon during its related surgical procedures.

Concepts: Neuroanatomy, Brain, Surgery, Cerebellum, Cranial nerves, Oculomotor nerve, Medulla oblongata, Brainstem

1

The authors describe the interpeduncular fossa safe entry zone as a route for resection of ventromedial midbrain lesions. To illustrate the utility of this novel safe entry zone, the authors provide clinical data from 2 patients who underwent contralateral orbitozygomatic transinterpeduncular fossa approaches to deep cavernous malformations located medial to the oculomotor nerve (cranial nerve [CN] III). These cases are supplemented by anatomical information from 6 formalin-fixed adult human brainstems and 4 silicone-injected adult human cadaveric heads on which the fiber dissection technique was used. The interpeduncular fossa may be incised to resect anteriorly located lesions that are medial to the oculomotor nerve and can serve as an alternative to the anterior mesencephalic safe entry zone (i.e., perioculomotor safe entry zone) for resection of ventromedial midbrain lesions. The interpeduncular fossa safe entry zone is best approached using a modified orbitozygomatic craniotomy and uses the space between the mammillary bodies and the top of the basilar artery to gain access to ventromedial lesions located in the ventral mesencephalon and medial to the oculomotor nerve.

Concepts: Biology, Cranial nerves, Anatomy, Mesencephalon, Cavernous sinus, Oculomotor nerve, Trochlear nerve, Basilar artery

1

OBJECTIVE Cavernous sinus meningiomas (CSMs) represent a cohort of challenging skull base tumors. Proper management requires achieving a balance between optimal resection, restoration of cranial nerve (CN) function, and maintaining or improving quality of life. The objective of this study was to assess the pre-, intra-, and postoperative factors related to clinical and neurological outcomes, morbidity, mortality, and tumor control in patients with CSM. METHODS A retrospective review of a single surgeon’s experience with microsurgical removal of CSM in 65 patients between January 1996 and August 2013 was done. Sekhar’s classification, modified Kobayashi grading, and the Karnofsky Performance Scale were used to define tumor extension, tumor removal, and clinical outcomes, respectively. RESULTS Preoperative CN dysfunction was evident in 64.6% of patients. CN II deficits were most common. The greatest improvement was seen for CN V deficits, whereas CN II and CN IV deficits showed the smallest degree of recovery. Complete resection was achieved in 41.5% of cases and was not significantly associated with functional CN recovery. Internal carotid artery encasement significantly limited the complete microscopic resection of CSM (p < 0.0001). Overall, 18.5% of patients showed symptomatic recurrence after their initial surgery (mean follow-up 60.8 months [range 3-199 months]). The use of adjuvant stereotactic radiosurgery (SRS) after microsurgery independently decreased the recurrence rate (p = 0.009; OR 0.036; 95% CI 0.003-0.430). CONCLUSIONS Modified Kobayashi tumor resection (Grades I-IIIB) was possible in 41.5% of patients. CN recovery and tumor control were independent of extent of tumor removal. The combination of resection and adjuvant SRS can achieve excellent tumor control. Furthermore, the use of adjuvant SRS independently decreases the recurrence rates of CSM.

Concepts: Oncology, Internal carotid artery, Common carotid artery, Cranial nerves, Cavernous sinus, Oculomotor nerve, Trochlear nerve, Cavernous part of internal carotid artery

1

The passage of time can be estimated either explicitly, e.g. before leaving home in the morning, or implicitly, e.g. when catching a flying ball. In the present study, the latency of saccadic eye movements was used to evaluate differences between implicit and explicit timing. Humans were required to make a saccade between a central and a peripheral position on a computer screen. The delay between the extinction of a central target and the appearance of an eccentric target was the independent variable that could take one out of four different values (400, 900, 1400 or 1900 ms). In target trials, the delay period lasted for one of the four durations randomly. At the end of the delay, a saccade was initiated by the appearance of an eccentric target. Cue&target trials were similar to target trials but the duration of the delay was visually cued. In probe trials, the duration of the upcoming delay was cued, but there was no eccentric target and subjects had to internally generate a saccade at the estimated end of the delay. In target and cue&target trials, the mean and variance of latency distributions decreased as delay duration increased. In cue&target trials latencies were shorter. In probe trials, the variance increased with increasing delay duration and scalar variability was observed. The major differences in saccadic latency distributions were observed between visually-guided (target and cue&target trials) and internally-generated saccades (probe trials). In target and cue&target trials the timing of the response was implicit. In probe trials, the timing of the response was internally-generated and explicitly based on the duration of the visual cue. Scalar timing was observed only during probe trials. This study supports the hypothesis that there is no ubiquitous timing system in the brain but independent timing processes active depending on task demands.

Concepts: Eye, Saccade, Eye movement, Eye tracking, Eye movement in language reading, Probability theory, The Independent, Oculomotor nerve

0

Hyaluronic acid (HA) is the most popular agent today for intradermal injections to improve wrinkles and other cosmetic defects. Ischemic necrosis due to injection of HA is one of the serious complications. Because there are many vascular branches around the nose, caution and care should be given during facial filler injection. Although the incidence is rare, blindness and permanent visual loss may occur. We describe a 29-year-old woman presented with painful erythematous swelling with violaceous patch on right periocular area and glabella after HA filler injection. After injecting the filler, she felt pain and dizziness, and her vision became blurred. She immediately received hyaluronidase around the HA filler inject area and during hospitalized for 10 days, she was successfully treated with systemic steroid, vasodilator, prophylactic antibiotics, and LLLT (low-level laser therapy) without any defects.

Concepts: Inflammation, Therapy, Cranial nerves, Ischemia, Low level laser therapy, Oculomotor nerve, Laser medicine, Oculomotor nerve palsy