Microneurosurgical removal of thalamic lesions: surgical results and considerations from a large, single-surgeon consecutive series

Balloon-Assisted Corpus Callosotomy. Reducing the Impact of Transcallosal Approaches

BACKGROUND

The interhemispheric transcallosal approach is widely used to remove intraventricular lesions. Corpus callosotomy gives immediate access to the ventricular chambers but is invasive in nature. Loss of callosal fibers, although normally tolerate, may cause disturbances ranging from a classical disconnection syndrome up to minor neuropsychological changes.

OBJECTIVE

To open an operative window in the corpus callosum through separation rather than disconnection of the white matter fibers.

METHODS

In 7 patients undergoing the interhemispheric transcallosal approach for intraventricular lesions, lying around or below the foramen of Monro, a stoma was created within the corpus callosum by using a 4F Fogarty catheter. The series included 3 colloid of the third ventricle, 2 thalamic cavernomas, 1 subependymoma, and 1 ependymoma of the foramen of Monro. We illustrate the technique and the clinico-radiological outcome, focusing on the size of callosotomy as seen on postoperative MRI.

RESULTS

The balloon-assisted corpus callosotomy provided a circular, smooth-walled access to the ventricular chambers, which allowed uncomplicated removal of the lesions. On postoperative MRI, the size of the callosotomy shrinked compared with surgery (2.8-6.4 mm at follow-up vs 6-9 mm as measured intraoperatively). No signs of disconnection syndrome or new permanent deficits were observed in this series.

CONCLUSION

The balloon-assisted technique produces a small callosotomy, without clinical consequences, showing a self-closing trend on postoperative MRI. This technique is a rewarding tool to reduce the impact of callosotomy while keeping the advantages of microsurgical interhemispheric approaches.

Are Thalamic Intrinsic Lesions Operable? No-Man's Land Revisited by the Analysis of a Large Retrospective, Mono-Institutional, Cohort

Thalamic gliomas represent a heterogeneous subset of deep-seated lesions for which surgical removal is advocated, although clear prognostic factors linked to advantages in performance status or overall survival are still lacking. We reviewed our Institutional Cancer Registry, identifying patients who underwent surgery for thalamic gliomas between 2006 and 2020. Associations between possible prognostic factors such as tumor volume, grade, the extent of resection and performance status (PS), and overall survival (OS) were evaluated using univariate and multivariate survival analyses. We found 56 patients: 31 underwent surgery, and 25 underwent biopsy. Compared to biopsy, surgery resulted positively associated with an increase in the OS (hazard ratio, HR, at multivariate analysis 0.30, 95% confidence interval, CI, 0.12-0.75). Considering the extent of resection (EOR), obtaining GTR/STR appeared to offer an OS advantage in high-grade gliomas (HGG) patients submitted to surgical resection if compared to biopsy, although we did not find statistical significance at multivariate analysis (HR 0.53, 95% CI 0.17-1.59). Patients with a stable 3-month KPS after surgery demonstrated to have a better prognosis in terms of OS if compared to biopsy (multivariate HR 0.17, 95% CI, 0.05-0.59). Age and histological grades were found to be prognostic factors for this condition (p = 0.04 and p = 0.004, respectively, chi-square test). Considering the entire cohort, p53 positivity (univariate HR 2.21, 95% CI 1.01-4.82) and ATRX positivity (univariate HR 2.69, 95% CI 0.92-7.83) resulted associated with a worse prognosis in terms of OS. In this work, we demonstrated that surgery aimed at tumor resection might offer a stronger survival advantage when a stable 3-month KPS after surgery is achieved.

Assessment the neurodegenaration process of post-geniculate optic pathway in thalamic tumors using optical coherence tomography: Post-geniculate optic pathway in thalamic tumors

PURPOSE

To investigate the effect of thalamic tumors related to post-geniculate optic pathway and those of microsurgical removal on neurodegeneration process of visual pathway using OCT.

METHODS

This cross-sectional study included 30 eyes of 15 patients with thalamic tumors and data compiled from 45 eyes of 45 healthy participants. The analysis of variables was divided into ipsilateral and contralateral eye depends on the laterality of brain tumors. The data gained at baseline, postoperative 3rd and postoperative 6th month period was analyzed in One-Way Repeated Measures ANOVA.

RESULTS

The mean superior quadrant retinal nerve fiber layer (RNFL) thickness of ipsilateral eye was significantly thicker (p = 0.02), while inferior hemifield ganglion cell-inner plexiform layer (GC-IPL) thickness of contralateral eye was significantly higher compared to control groups (p = 0.02). Significant negative correlations were found between the mean preop. mean deviation (MD) and tumor volume and time interval between initial diagnosis and surgery (r = - 0.730, p = 0.002 and r = - 0.680, p = 0.005, respectively) in the ipsilateral eye. In repeated measure analysis, there was no unfavourable effect of thalamic microsurgery on peripapillary average RNFL thickness on both ipsilateral and contralateral eyes (Ipsilateral eye; f (1.5,21.7) 0.76 p = 0.51 and contralateral eye; f (1.4,20.4) 0.42 p = 0.59).

CONCLUSION

This study suggests that thalamic tumors affecting post-geniculate optic pathway may lead to significant increase in RNFL and GC-IPL thicknesses and changes in VF parameters. Timely intervention in thalamic tumors may prevent irreversible loss of retinal axons secondary to neurodegeneration process.

Survival and functional outcomes in paediatric thalamic and thalamopeduncular low grade gliomas

BACKGROUND

Childhood thalamopeduncular gliomas arise at the interface of the thalamus and cerebral peduncle. The optimal treatment is total resection but not at the cost of neurological function. We present long-term clinical and oncological outcomes of maximal safe resection.

METHODS

Retrospective review of prospectively collected data: demography, symptomatology, imaging, extent of resection, surgical complications, histology, functional and oncological outcome.

RESULTS

During 16-year period (2005-2020), 21 patients were treated at our institution. These were 13 girls and 8 boys (mean age 7.6 years). Presentation included progressive hemiparesis in 9 patients, raised intracranial pressure in 9 patients and cerebellar symptomatology in 3 patients. The tumour was confined to the thalamus in 6 cases. Extent of resection was judged on postoperative imaging as total (6), near-total (6) and less extensive (9). Surgical complications included progression of baseline neurological status in 6 patients, and 5 of these gradually improved to preoperative status. All tumours were classified as low-grade gliomas. Disease progression was observed in 9 patients (median progression-free survival 7.3 years). At last follow-up (median 6.1 years), all patients were alive, median Lansky score of 90. Seven patients were without evidence of disease, 6 had stable disease, 7 stable following progression and 1 had progressive disease managed expectantly.

CONCLUSION

Paediatric patients with low-grade thalamopeduncular gliomas have excellent long-term functional and oncological outcomes when gross total resection is not achievable. Surgery should aim at total resection; however, neurological function should not be endangered due to excellent chance for long-term survival.

Cottonoid-guided intraoperative ultrasonography in neurosurgery: a proof-of-concept single surgeon case series

Ultrasonography was introduced into neurosurgery in the 1950s, but its successful utilization as an intraoperative tool dates from the early 1980s. However, it was not used widely because of limited technology, a lack of specific training, and, most importantly, the concurrent evolution of computerized tomography and magnetic resonance imaging. The intraoperative use of cottonoid patties as acoustical markers was first described in 1984, but the practice did not gain acceptance, and no articles have been published since. Herein, we reconsider the echogenic properties of the surgical cottonoid patty and demonstrate its usefulness with intraoperative ultrasonography (ioUS) in neurosurgical practice as a truly real-time neuronavigation tool. We also discuss its advantages and compare it with other intraoperative image guidance tools. The echogenic properties of the handmade cottonoid patties in various sizes used with ioUS are described. Details of our cottonoid-guided ioUS technique and its advantages with illustrated cases are also described. As an echogenic marker, cottonoid patties can be easily recognized with ioUS. Their usage with ultrasonography provides truly real-time anatomical orientation throughout the surgery, allowing easy access to intraparenchymal pathologies, and precise and safer resection. Cottonoid-guided ioUS helps not only to localize intraparenchymal pathologies but also to delineate the exact surgical trajectory for each type of lesion. Furthermore, it is not affected by brain shift and distortion. Thus, it is a truly real-time, dynamic, cost-effective, and easy-to-use image guidance tool. This technique can be used safely for every intraparenchymal pathology and increases the accuracy and safety of the surgeries.

Surgical Approach to Thalamic Tumors

Thalamic tumors are deep-seated lesions. Recent improvements in therapeutic approaches and surgical techniques have allowed a more accurate approach to these lesions and a reduction in morbidity and mortality. In this article, the various surgical approaches for the resection of thalamic tumors are described. Each of these approaches has its own indications and risk of complications. Resection of thalamic tumors needs specific anatomical knowledge, especially the vascular anatomy of the region and the thalamic peduncles.

Thalamic gliomas in adults: a systematic review of clinical characteristics, treatment strategies, and survival outcomes

PURPOSE

Thalamic gliomas are rare neoplasms that pose significant surgical challenges. The literature is limited to single-institution retrospective case series. We systematically review the literature and describe the clinical characteristics, treatment strategies, and survival outcomes of adult thalamic gliomas.

METHODS

Relevant articles were identified on PubMed, Scopus, and Cochrane databases. Papers containing cases of adult thalamic gliomas with clinical outcome data were included. A comprehensive review of clinical characteristics and survival analysis was conducted.

RESULTS

We included 25 studies comprising 617 patients. The median age was 45 years (male = 58.6%). Glioblastoma was the most frequent histological type (47.2%), and 82 tumors were H3 K27M-mutant. Motor deficit was the most common presenting symptom (51.8%). Surgical resection was performed in 69.1% of cases while adjuvant chemotherapy and radiotherapy were administered in 56.3% and 72.6%, respectively. Other treatments included laser interstitial thermal therapy, which was performed in 15 patients (2.4%). The lesion laterality (P = 0.754) and the surgical approach (P = 0.111) did not correlate with overall survival. The median progression-free survival was 9 months, and the overall two-year survival rate was 19.7%. The two-year survival rates of low-grade and high-grade thalamic gliomas were 31.0% and 16.5%, respectively. H3 K27M-mutant gliomas showed worse overall survival (P = 0.017).

CONCLUSION

Adult thalamic gliomas are associated with poor survival. Complete surgical resection is associated with improved survival rates but is not always feasible. H3 K27M mutation is associated with worse survival and a more aggressive approach should be considered for mutant neoplasms.