Radiosurgical Decompression of Trigeminal Nerve and Its Correlation with Functional Outcome in Tumor-Related Trigeminal Neuralgia.

BACKGROUND: Target selection during Gamma Knife radiosurgery (GKRS) in cases of tumor-related trigeminal neuralgia is always debatable. We analyzed the correlation of regression of tumor size and degree of release of the nerve with long-term pain control. METHODS: Between March 2012 and March 2023, 50 cases of tumor-related trigeminal neuralgia were treated with GKRS (tumor was targeted). Radiological findings after GKRS were categorized into 3 types: 1) tumor volume remained same or decreased, additional segment of nerve not seen; 2) tumor volume decreased, additional segment of trigeminal nerve seen, but tumor still adherent to the nerve; 3) tumor volume decreased, adjacent nerve seen completely separated from tumor. Pain score before and after GKRS (Barrow Neurological Institute I-III: good; Barrow Neurological Institute IV and V: poor) was correlated with these subgroups. RESULTS: At median follow-up of 46.5 months, 18 cases showed type 1 radiological response, 23 showed type 2 response, and 9 showed type 3 response. Good pain control was achieved in 10 (55.5%) patients with type 1, 15 (65.21%) with type 2, and 7 (77.8%) with type 3 responses. The outcome differences among these 3 groups were not statistically significant (P = 0.519). Five patients with type 3 radiological response were off medication, which was statistically better than type 1 and type 2 radiological responses, with 3 patients (P = 0.012) and 2 patients (P = 0.002), respectively, still receiving medication. CONCLUSIONS: Tumor volume reduction after GKRS may be associated with good pain control in tumor-related trigeminal neuralgia. Further, this allows visualization of additional segment of nerve that can be targeted in a second session for treating recurrent or failed cases.

COVID-19: changing patterns among neurosurgical patients from North India, efficacy of repeat testing, and inpatient prevalence.

OBJECTIVE: COVID-19 has affected surgical practice globally. Treating neurosurgical patients with the restrictions imposed by the pandemic is challenging in institutions with shared patient areas. The present study was performed to assess the changing patterns of neurosurgical cases, the efficacy of repeated testing before surgery, and the prevalence of COVID-19 in asymptomatic neurosurgical inpatients. METHODS: Cases of non-trauma-related neurosurgical patients treated at the Postgraduate Institute of Medical Education and Research (PGIMER) before and during the COVID-19 pandemic were reviewed. During the pandemic, all patients underwent a nasopharyngeal swab reverse transcription-polymerase chain reaction test to detect COVID-19 at admission. Patients who needed immediate intervention were surgically treated following a single COVID-19 test, while stable patients who initially tested negative for COVID-19 were subjected to repeated testing at least 5 days after the first test and within 48 hours prior to the planned surgery. The COVID-19 positivity rate was compared with the local period prevalence. The number of patients who tested positive at the second test, following a negative first test, was used to determine the probable number of people who could have become infected during the surgical procedure without second testing. RESULTS: Of the total 1769 non-trauma-related neurosurgical patients included in this study, a mean of 337.2 patients underwent surgery per month before COVID-19, while a mean of 184.2 patients (54.6% of pre-COVID-19 capacity) underwent surgery per month during the pandemic period, when COVID-19 cases were on the rise in India. There was a significant increase in the proportion of patients undergoing surgery for a ruptured aneurysm, stroke, hydrocephalus, and cerebellar tumors, while the number of patients seeking surgery for chronic benign diseases declined. At the first COVID-19 test, 4 patients (0.48%) tested were found to have the disease, a proportion 3.7 times greater than that found in the local community. An additional 5 patients tested positive at the time of the second COVID-19 test, resulting in an overall inpatient period prevalence of 1%, in contrast to a 0.2% national cumulative caseload. It is possible that COVID-19 was prevented in approximately 67.4 people every month by using double testing. CONCLUSIONS: COVID-19 has changed the pattern of neurosurgical procedures, with acute cases dominating the practice. Despite the fact that the pandemic has not yet reached its peak in India, COVID-19 has been detected 3.7 times more often in asymptomatic neurosurgical inpatients than in the local community, even with single testing. Double testing displays an incremental value by disclosing COVID-19 overall in 1 in 100 inpatients and thus averting its spread through neurosurgical services.

Pilocytic Astrocytoma with Gangliocytic Differentiation to Pilomyxoid Astrocytoma-expanding the Morphological Spectrum: Case Report and Literature Review.

We present a rare case of pilocytic astrocytoma (PA) with gangliocytic differentiation arising in the suprasellar/chiasmatic region in a young boy that showed a rapid regrowth after the 1st subtotal resection and "differentiated" into pilomyxoid astrocytoma (PMA) in subsequent recurrences. The clinical course, imaging, and histological features have been described with a review of the literature. While PA is well-circumscribed, biphasic tumors with bipolar piloid cells, those arising in the diencephalic region often contain myxoid stroma, angiocentric pattern, and "intermediate" features between PA and PMA. Examples of PMA "maturing" to PA are also on record; however, PA with gangliocytic component differentiating to PMA has not been described in the literature to the best of our knowledge.

Microsurgical Anatomy of Medial Temporal Lobe in North-West Indian Population: Cadaveric Brain Dissection.

AIM: The medial temporal lobe (MTL) is a highly complex neuroanatomical structure of tremendous neurosurgical importance. It is a common site for epilepsy, vascular lesions, and tumors. Owing to the critical location behind the sphenoid wing, it is more prone for traumatic contusion often with surgical implications. Hence, its microneurosurgical anatomy needs to be evaluated in detail. MATERIALS AND METHODS: Twelve formalin-fixed human cadaveric brains from North-west Indian population were dissected under neurosurgical microscope and various dimensions of the MTL and their distance from important neurovascular structures were measured. RESULTS: The MTL consists of important neural structures such as parahippocampal gyrus, uncus, hippocampus, temporal horn, and choroidal fissure. The average distance of tentorium from the uncus was 1.96 mm. The temporal horn and the inferior choroidal point were located from the anterior temporal pole at 22.9 mm and 30.9 mm, respectively. Important vessels that are intimately related to the MTL were anterior choroidal artery (AchA), posterior communicating artery, the P1 segment of posterior cerebral artery, and the M1 segment of middle cerebral artery. CONCLUSION: Complex anatomic and cytostructural organization makes the MTL unique. In this study, along with the descriptive anatomy, morphometric measurements of various structures were performed. The uncus and its relation to other neurovascular structures is well described in literature, but its exact distance from them as determined in this study is particularly helpful in guiding the surgeons while approaching in this area. Knowledge of the distance of the temporal horn from various surfaces is important while opening the temporal horn to avoid unnecessary damage to nearby structures.

A case of intrauterine diagnosed posterior fossa dermoid presenting in childhood.

Intrauterine intracranial brain tumor is a rare entity. Traditionally, the outcome of this tumor had been dismal. In a large series of congenital brain tumor, the commonest have been teratoma followed by astrocytoma and craniopharyngioma. We report a case of intracranial dermoid in post-fossa diagnosed at 8 months of intrauterine life during routine prenatal ultrasonography. The child's clinical picture, the surgery performed and the final outcome have been discussed. As far as our knowledge goes, this is perhaps the first reported case of intrauterine-diagnosed intracranial dermoid.

Long-term outcome in surviving patients after clipping of intracranial aneurysms.

OBJECTIVE: The quality of life and functional outcome may be significantly impaired in patients of aneurysmal subarachnoid hemorrhage. The purpose of the present study was to assess the status of patients undergoing surgical clipping of intracranial aneurysms in a long-term follow-up and to identify factors affecting outcome. METHODS: 494 patients who underwent clipping of their intracranial aneurysms with a minimum follow-up of 1 year after their discharge were studied. Preoperative factors such as age, Hunt and Hess grade, Fisher grade, time interval between ictus and surgery, and site of aneurysm were recorded. The long-term status was assessed using Glasgow Outcome Scale (GOS), Modified Rankin Scale (MRS), Barthel index (BI), and Mini-Mental State Examination (MMSE). RESULTS: Site of aneurysm and ictus-surgery interval did not have any effect on any parameter at long-term follow-up. Majority of patients who were discharged continued to improve as measured by GOS, Modified Rankin Scale, and Barthel index. However a significant proportion of patients had impaired MMSE at long-term follow-up. Multivariate analysis showed a significant effect of age on MMSE and also a positive correlation between number of aneurysms and GOS. CONCLUSIONS: Most patients who survived and were discharged continued to improve in the postoperative period even though the immediate postoperative outcome was not favorable in many. However, a substantial subset had impaired cognitive function.

Extracranially located PICA aneurysm presenting with supratentorial IVH: A rare event with diagnostic pitfalls.

Extracranially located posterior inferior cerebellar artery (PICA) aneurysms are rare with only 21 cases reported till date. They may arise either from the proximal segment of an extracranially originating PICA or from the tip of its caudal loop when it dips below the foramen magnum. A 16-year-old female presenting with sudden onset severe headache and intraventricular hemorrhage (IVH) in the occipital horns of the lateral ventricle and the fourth ventricles, was diagnosed to have an extracranial proximal segment PICA aneurysm on a four vessel digital subtraction angiography (DSA), after initially missing it on the brain magnetic resonance imaging (MRI) with angiogram (MRA) because of its extracranial location. During surgery, the aneurysm was clipped following a far lateral suboccipital craniectomy with C1-C2 hemilaminectomy. The patient showed good recovery. Thus, we emphasize the need for a dedicated four vessel angiography to diagnose such lesions.

Hypothalamic glioma masquerading as craniopharyngioma.

Hypothalamic glioma account for 10-15% of supratentorial tumors in children. They usually present earlier (first 5 years of age) than craniopharyngioma. Hypothalamic glioma poses a diagnostic dilemma with craniopharyngioma and other hypothalamic region tumors, when they present with atypical clinical or imaging patterns. Neuroimaging modalities especially MRI plays a very important role in scrutinizing the lesions in the hypothalamic region. We report a case of a hypothalamic glioma masquerading as a craniopharyngioma on imaging along with brief review of both the tumors.

Embryogenesis of triple neural tube defects: sonic hedgehog--a key?

Neural tube closure is a complex spatio-temporal process. Multiple neural tube defects (NTDs) in a single patient are extremely rare. Only a few cases of multiple NTDs have been reported in the world literature, including less than 20 cases of double NTDs and 3 cases of triple NTDs. We report a fourth case of triple NTDs and review the literature regarding the embryogenesis. An effort is made to understand the theories of neural tube closure in light of recent advances in molecular biology and identification of the signaling pathways involved.

Angiolipoma of the right inferior colliculus: a rare central cause of hearing loss and limb ataxia.

Intracranial angiolipomas are rare entities and are infrequently symptomatic. These benign lesions are adherent to the surrounding neurovascular structures as they share the same blood supply, which limits their resectability, and impose a possibility of persistence of symptoms. However, due to recent advancements in the neuro-radiological fields and microneurosurgical techniques it has been possible to localise precisely and excise these lesions with low morbidity and mortality. The authors present an interesting rare case of intracranial angiolipoma of the right inferior colliculus situated in the quadrigeminal plate cistern. The patient had presented with ipsilateral hearing loss and upper limb ataxia. Interesting clinical findings, neuro-imaging studies and peroperative features are presented and discussed along with a brief review of the literature.