Hyperechoic Area Under Insular Gliomas: A Potentially Hazardous Intraoperative Ultrasound Artifact.

BACKGROUND: Intraoperative ultrasound (IOUS) images can be distorted by various artifacts. During surgeries for insular low-grade gliomas (LGGs), we repeatedly observed a distinct hyperechoic artifact adjacent to medial tumor borders, localized in brain regions with normal appearance on magnetic resonance imaging (MRI) that has not been reported before. METHODS: We retrospectively evaluated saved 3-dimensional (3D) IOUS images of 20 patients harboring insular LGGs. Twelve patients were operated on between 2010 and 2015 using an older navigated 3D IOUS system. Additionally, 3D-IOUS images of 8 patients operated on between 2021 and 2023 using a new high-end 3D-IOUS system were evaluated. The investigated region was the area under medial tumor borders, which were defined using preoperative MRI. RESULTS: In 17 out of 20 cases (85%), a distinct hyperechoic area adjacent to medial tumor borders localized in brain regions with normal appearance on preoperative MRI was found; in the remaining 3 cases the saved images were suboptimal and did not allow evaluation of the area under the medial tumor borders. CONCLUSIONS: Although the causes of this bright artifact are unclear, we can hypothesize that the reverberation in between different parallel layers of white and gray matter localized under the insula could play a role in its appearance. Importantly, as this hyperechoic area was depicted already before any tumor resection, it may lead to erroneous conclusion that the tumor spreads more medially. Potential resection in this region may cause significant neurologic sequelae.

Navigated 3D-ultrasound power Doppler and visualization of lenticulostriate arteries during resections of insular gliomas.

•Preservation of LSAs is extremely important during resections of insular gliomas.•Navigated 3D-US power Doppler may enable intraoperative visualization of LSAs.•Quality of ultrasound scanner is important when LSAs should be visualized.•Reliability of LSAs depiction by 3D-US power Doppler is still investigated.

Current Limitations of Intraoperative Ultrasound in Brain Tumor Surgery.

While benefits of intraoperative ultrasound (IOUS) have been frequently described, data on IOUS limitations are relatively sparse. Suboptimal ultrasound imaging of some pathologies, various types of ultrasound artifacts, challenging patient positioning during some IOUS-guided surgeries, and absence of an optimal IOUS probe depicting the entire sellar region during transsphenoidal pituitary surgery are some of the most important pitfalls. This review aims to summarize prominent limitations of current IOUS systems, and to present possibilities to reduce them by using ultrasound technology suitable for a specific procedure and by proper scanning techniques. In addition, future trends of IOUS imaging optimization are described in this article.

Large Residual Pilocytic Astrocytoma After Failed Ultrasound-Guided Resection: Intraoperative Ultrasound Limitations Require Special Attention.

While benefits of neurosurgical intraoperative ultrasound (IOUS) are reported frequently, this method still has some significant pitfalls, which are described less often. However, sufficient knowledge on dealing with IOUS drawbacks, particularly various image artifacts, is important for successful surgery. We report a case of failed IOUS-guided pediatric cerebellar pilocytic astrocytoma resection, incorrectly evaluated as gross total resection according to IOUS. A large tumor residuum was left in place. Successful IOUS-guided reoperation using new IOUS technology and appropriate ultrasound imaging technique are described. The most probable reasons for initial resection failure and crucial points of reoperation, predominantly dealing with IOUS artifacts, are discussed. Neurosurgeons should be aware of IOUS limitations and have sufficient knowledge about how to overcome them before adopting routine use of this intraoperative imaging modality.

[Cyclic Cushings syndrome: a case study and overview]. / Cyklický Cushingov syndróm: kazuistika a prehlad.

Cushings syndrome and especially Cushing´s disease represent diagnostically and therapeutically complicated medical situations. In some patients, cyclic changes in cortisol production additionally hamper the diagnosis in terms of source identification and management of hormone overproduction. It may not be clear, whether the patient is cured or not even years after the treatment. It is a rare disorder variant, but we assume that it is underdiagnosed and it´s incidence is actually higher. The article deals with a complicated course of diagnosis and treatment in a patient with cyclic Cushings syndrome.Key words: Cushing´s disease - cyclic Cushing´s syndrome - hypercortisolism.

Navigated 3D-ultrasound versus conventional neuronavigation during awake resections of eloquent low-grade gliomas: a comparative study at a single institution.

BACKGROUND: The data showing usefulness of navigated 3D-ultrasound (3DUS) during awake resections of eloquent gliomas are sparse. Results of surgeries performed using 3DUS were never compared to procedures guided by standard neuronavigation. The aim of this work is to assess the effectiveness of 3DUS during awake resections of eloquent low-grade gliomas (LGGs) by comparing surgical results of two series of patients operated on using conventional neuronavigation and using 3DUS. To our knowledge, a similar study is lacking in the literature. METHODS: During a 4-year period (September 2006 to August 2010) 21 awake resections of LGGs guided by neuronavigation (series 1, S1) were consecutively performed in Department of Neurosurgery in Bratislava. During another 4-year period (August 2010 to July 2014) 28 awake resections of LGGs guided by 3DUS (series 2, S2) were consecutively conducted. In both patients series, the eloquent cortical and subcortical structures were intraoperatively detected by direct electrical stimulation. Extent of tumor resection (EOR) and functional outcome in both series were compared. RESULTS: EOR was significantly greater (p = 0.022) in S2 (median = 93.25%; mean = 86.79%), as compared to S1 (median 87.1%; mean = 75.85%). One permanent minor deficit in S1 and 2 minor deficits in S2 occurred, the difference was not significant (p = 0.999). CONCLUSIONS: Our work represents the first study comparing results of surgeries guided by 3DUS versus conventional navigation. The extent of awake resections of eloquent LGG guided by 3DUS was greater comparing to awake resections guided by standard neuronavigation; use of 3DUS had no impact on the number of new permanent deficits.

Intraspinal intradural variations of nerve roots.

PURPOSE: The aim of this work is to point out the intraspinal anatomical variations of nerve roots and their possible participation in radiculopathy. METHODS: The anatomical study was performed in 33 cadavers. There were 25 male cadavers aged 30-75 years and 8 female cadavers aged 45-77 years, with a mean age of 46.5 years to 24 h from death. All intradural rami communicantes between nerve roots were excised and examined histologically for the presence or absence of nervous tissue. The type of the plexus was defined by subtracting from the root C2. RESULTS: Findings of the normotype of plexus formation occurred in 24 cases (72.7%). Variations in its formation were observed in nine cases (27.3%). The prefixed type was observed in six cases (18.2%), postfixed type in three cases (9.1%). The formation of isolated prefixed or postfixed type of the brachial and lumbosacral plexus was not observed. Anatomical preparations revealed intradural variations in all cases of the lumbosacral plexus, 22 times (66.7%) in cases of cervical roots, and in the thoracic region seven times (21.2%). Variations occurred more frequently in variations of plexus formation. CONCLUSIONS: This study allowed us to identify and describe unpublished intraspinal intradural anatomical variations of nerve roots, and their interrelationships throughout the spinal canal with their potential influence on the clinical picture. Anatomical preparations revealed a higher incidence of intraspinal intradural variations, particularly between sacral roots. Reliance of their incidence of the plexus type was observed.

Late-onset jaw and teeth pain mimicking trigeminal neuralgia associated with chronic vagal nerve stimulation: case series and review of the literature.

BACKGROUND: Vagal nerve stimulation (VNS) for refractory epilepsy is well established. Trigeminal neuralgia itself is a common disease in adults, and thus, late-onset pain in the trigeminal region under VNS, which is extremely rare, may not be recognized as caused by VNS. CASE PRESENTATION: Two patients with drug-resistant symptomatic epilepsy treated with chronic VNS experienced stimulation-related pain in the lower and upper jaw and teeth on the side of stimulation. No evidence of local spread of the stimulation current was present. The pain started with a delay of years after device implantation and weeks after the last increase in the pacing parameters. At the time of onset, the pain was not recognized as VNS-related, leading to extensive examinations. The trigeminal neuralgia-like pain resolved after adjustment of the stimulation current intensity. In one of the patients, the pain disappeared within one to two days following every epileptic seizure. To our knowledge, this is the first case report of late-onset trigeminal pain under VNS revealing a direct link between epileptogenic and pain processes. CONCLUSION: A painless interval between the last change of the pacing parameters and trigeminal pain can lead to the erroneous interpretation that this is a typical trigeminal neuralgia. The lack of its recognition as a side effect of VNS can lead to unnecessary examinations and delayed adjustment of stimulation parameters. In patients with signs of late-onset trigeminal pain under VNS with normal electrode impedance and no evidence of local current spread, the replacement of the VNS lead does not seem to be beneficial. A review of the literature on VNS side effects including pain and device malfunctions was undertaken.

Intraspinal extradural variations of nerve roots.

INTRODUCTION: The aim of this work is to point out the intraspinal extradural anatomical variations of nerve roots and their possible participation in radiculopathy. METHODS: The anatomical study was performed in 33 cadavers at a mean age of 46.5 and up to 24h from death. All extradural anastomoses between nerve roots were excised and examined histologically for the presence or absence of nervous tissue. The type of the plexus was defined by subtracting from the root C2. RESULTS: Findings with the normotype of plexus formation prevailed in 24 cases (72.7%). Variations in its formation were observed in 9 cases (27.3%). The prefixed type in 6 cases (18.2%), post-fixed type in 3 cases (9.1%). We did not observe the formation of the isolated prefixed or post-fixed types in the brachial or lumbosacral plexuses. Extradural anatomical variations occurred in 20 cases (60.6%). They were more frequent on the left, in 10 cases (30.3%), bilateral in 3 cases (9.1%). In 8 instances (24.2%), the atypical spacing, including four in the lumbosacral region, was observed. Variations occurred more frequently in variations of formation of the plexus. CONCLUSIONS: This study allowed us to identify and describe unpublished intraspinal extradural anatomical variations of nerve roots and their interrelationships throughout the spinal canal with their potential influence on the clinical picture. Anatomical preparations revealed a higher incidence of intraspinal extradural variations, mainly between sacral roots. The reliance of their incidence of the type of plexus was observed.

Visualization of lenticulostriate arteries during insular low-grade glioma surgeries by navigated 3D ultrasound power Doppler: technical note.

OBJECTIVE Resection of insular gliomas is challenging. In cases of intraoperative injury to the lenticulostriate arteries (LSAs), the usual result is a dense hemiplegia. LSAs are usually localized just behind the medial tumor border but they can also be encased by the tumor. Thus, exact localization of these perforators is important. However, intraoperative localization of LSAs using conventional neuronavigation can be difficult due to brain shift. In this paper, the authors present a novel method of intraoperative LSA visualization by navigated 3D ultrasound (3DUS) power Doppler. This technique enables almost real-time imaging of LSAs and evaluation of their shift during insular tumor resections. METHODS Six patients harboring insular Grade II gliomas were consecutively operated on at the Department of Neurosurgery in Bratislava using visualization of LSAs by navigated 3DUS power Doppler. In all cases, the 3DUS data were repeatedly updated to compensate for the brain shift and display the actual position of LSAs and residual tumor. RESULTS Successful visualization of LSAs was achieved in all cases. During all surgeries, the distance between the bottom of the resection cavity and LSAs could be accurately evaluated; in all tumors the resection approached the LSAs and only a minimal amount of tissue covering these perforators was intentionally left in place to avoid injury to them. CONCLUSIONS Visualization of LSAs by navigated 3DUS power Doppler is a useful tool that may help to prevent injury of LSAs during removal of insular low-grade gliomas. However, reliability of this method has to be carefully evaluated in further studies.

Direct electrical stimulation of the optic radiation in patients with covered eyes.

Direct electrical stimulation (DES) of the optic radiation (OR) during an awake tumor resection has been repeatedly reported. In all cases, visual function monitoring was performed in patients with open eyes which were looking at a picture. We report a new modification of the standard method, OR stimulation in patient with closed and covered eyes. To the best of our knowledge, this method was not presented before. According to our first experience, this methodology may be in some cases a potentially more sensitive form of neuromonitoring than the OR stimulation in patients with open eyes, as the phosphenes elicited by DES may be more distinct in patients with covered eyes. The technique is discussed, and a literature review on intraoperative identification of the OR is presented as well. However, a future prospective study is needed to confirm the relevance of our finding.

Nonfunctioning pituitary adenomas: association of Ki-67 and HMGA-1 labeling indices with residual tumor growth.

BACKGROUND: The postoperative biological behavior of nonfunctioning pituitary adenomas (NFPAs) is variable. Some residual NFPAs are stable long-term, others grow, and some recur despite complete removal. The usual histological markers of tumor aggressiveness are often similar between recurring, regrowing, and stable tumors, and therefore are not reliable as prognostic parameters. In this study, the clinical utility of proliferation indices (labeling index, Li) based on immunohistochemistry targeted at antigens Ki-67 and High-mobility group A1 (HMGA-1) for prediction of NFPA prognosis was investigated. METHODS: Fifty patients with NFPAs were investigated. In each patient, Ki-67 and HMGA-1 Li were evaluated. Based on postoperative magnetic resonance images, patients were classified as tumor-free (18 patients), or harboring a residual tumor (32 patients). The latter group was further subdivided into groups with stable tumor remnants (11 patients) or progressive tumor remnants (21 patients). RESULTS: The median follow-up period was 8 years. No significant relationship between HMGA-1 Li and residual tumor growth was found. Growing residual tumors showed a trend towards higher Ki-67 Li compared with stable ones (p = 0.104). All tumor remnants with Ki-67 Li above 2.2% were growing. The relationship between residual tumor growth and Ki-67 Li exceeding the cutoff value of 2.2% was significant (p = 0.01 in univariate, p = 0.044 in multivariate analysis). CONCLUSIONS: The prognostic significance of the HMGA-1 antigen was not confirmed. In contrast, the Ki-67 Li provides useful and valuable information for the postoperative management of NFPAs. In residual adenomas with a Ki-67 Li above 2.2%, regrowth should be expected, and these tumors may require shorter intervals of follow-up magnetic resonance imaging (MRI) and/or early adjuvant therapy. Future larger studies are needed to confirm the results of this study.

Recurrent craniopharyngiomas in children and adults: long-term recurrence rate and management.

BACKGROUND: The significance of the majority of the factors influencing the recurrence rate (RR) of craniopharyngiomas remains unclear, and the management of this significance is controversial. The present study aimed to evaluate the influence of patient age and tumor topography on the RR, the efficacy of radiotherapy, and the safety of surgery for recurrences. METHODS: The RR was analyzed in 38 children (follow-up, 2-256 months [mean, 147.6]) and 63 adults (follow-up, 2-221 months [mean, 100.2]. The efficacy of 18 sessions of radiotherapy (13 patients) and the outcome of 52 secondary surgeries (37 patients) were evaluated. RESULTS: The RR reached 39.5% in children and 22.2% in adults (p = 0.053). After radical tumor removal, the RR in children (36.7%) was significantly higher (p = 0.024) than that in adults (14%). In children after radical removal of intraventricular and extraventricular craniopharyngiomas (IECs), the RR was higher (60%; p = 0.071) than in extraventricular (intrasellar and suprasellar; purely suprasellar extraventricular) tumors (25%). Radical removal of 50% of tumors was achieved (73.1% in children; 26.9% in adults; p = 0.002) in 56.7% of the first and 40.9% of further recurrences. There was no early mortality after 52 surgeries; functional worsening (endocrine, 2; obesity, 2; visual, 3) occurred after 7/52 secondary surgeries. Recurrence occurred after 9/18 sessions of radiotherapy. CONCLUSIONS: The RR was higher in children than in adults and in IECs relative to other topographic groups. Children with IECs represent a risk group. The efficacy of radiotherapy was inconclusive. Early detection of recurrences enabled safe excision with low morbidity.

Navigated three-dimensional intraoperative ultrasound-guided awake resection of low-grade glioma partially infiltrating optic radiation.

We report a case of awake resection of temporal low-grade glioma infiltrating the optic radiation (OR). The OR was localized by direct electrical stimulation (DES) and the tumor was delineated by navigated intraoperative 3D ultrasound. Ultrasound artifacts were eliminated by 3D-ultrasound data acquisition with a miniature probe inserted into the resection cavity. A total of 97 % resection was achieved, and small tumor portion involving OR was intentionally left in place. Functional result was partial quadrantanopia instead of more profound visual deficit, which would follow gross-total resection. To our knowledge, DES of OR was reported once; the aforementioned method of ultrasound artifact elimination has not been reported before.

Craniopharyngiomas in children: how radical should the surgeon be?

PURPOSE: Two main modes of management of craniopharyngiomas, namely, radical tumor removal and intentional incomplete removal followed by radiotherapy, are used. Recently, a half-way solution was added. Radical removal is reserved only for the tumors not involving hypothalamus. Such tumors, however, are not clearly defined. The goal of the study was to clarify the relationship of craniopharyngiomas with surrounding structures, especially hypothalamus, and to evaluate its clinical significance. METHODS: Our policy of management of craniopharyngiomas was elaborated on the basis of the results of morphological studies of the topography and their correlation with magnetic resonance imaging (MRI) in 115 adults and children operated on since 1991. Suitability of the policy in children and adolescents was verified by long-term outcome analysis in 41 consecutive patients. RESULTS: The rate of morbidity and mortality was higher in patients with craniopharyngiomas located inside the third ventricle either partially (intraventricular and extraventricular craniopharyngiomas, IEVCs, 16 patients) or completely (intraventricular, one patient) than in tumors located outside the ventricle (suprasellar extraventricular, SEVCs, five patients; intrasellar and suprasellar, 19 patients). Postsurgical hypothalamic signs and symptoms occurred most often in intraventricular tumors; there were no mental disorders or obesity caused by primary removal of SEVCs including those severely compressing hypothalamus. CONCLUSIONS: Radical removal of SEVCs is safer than of IEVCs despite an apparent involvement of hypothalamus. In majority of cases, they may be distinguished by indirect MRI signs; in others only according to operation findings; final decision about the optimal extent of tumor removal should be made during surgery.

Persisting embryonal infundibular recess.

Persisting embryonal infundibular recess (PEIR) is a rare anomaly of the third ventricular floor that has an unclear pathogenesis. In all 7 previously described cases, PEIR was present in adult patients and was invariably associated with hydrocephalus and, in 4 reported cases, with an empty sella. These associated findings led to speculations about the role of increased intraventricular pressure in the development of PEIR. In the present case, PEIR was found in a 24-year-old man without the presence of hydrocephalus or empty sella. Disorders of pituitary function had been present since childhood. Magnetic resonance imaging revealed a cystic expansion in an enlarged sella turcica. A communication between the third ventricle and the sellar cyst was suspected but not apparent. During transcranial surgery, the connection was confirmed. Later, higher-quality MR imaging investigations clearly showed a communication between the third ventricle and the sellar cyst through a channel in the tubular pituitary stalk. This observation and knowledge about the embryology of this region suggests that PEIR may be a developmental anomaly caused by failure of obliteration of the distal part of primary embryonal diencephalic evagination. Thus, PEIR is an extension of the third ventricular cavity into the sella. Although PEIR is a rare anomaly, it is important to identify when planning a procedure on cystic lesions of the sella. Because attempts at removal using the transsphenoidal approach would lead to a communication between the third ventricle and the nasal cavity, a watertight reconstruction of the sellar floor is necessary.