The impact of selection bias in the treatment for ruptured anterior communicating artery aneurysms: different results or different patients?

Background: Anterior communicating artery is one of the most frequent locations for the development of intracranial aneurysm. The availability and advances of different treatments modalities allows for case-specific selection, but potentially impacts our ability to assess equipoise among them. Objective: Investigate and compare clinical and morphological variables among surgical and endovascular treatment groups with ruptured anterior communicating artery aneurysms. Methods: Data from patients from a single university hospital treated for ruptured anterior communicating aneurysms after multidisciplinary discussion in a period from January 2009 to January 2020 were retrospectively reviewed. Demographics, clinical status, aneurysm morphologic features and in-hospital complications were registered for each treatment (endovascular coiling vs. microsurgical clipping). Clinical assessment was made from outpatient evaluation at 1-year follow-up. Results: A total of 119 patients was obtained adding surgical (n = 80) and endovascular (n = 39) treatment groups. No significant changes between groups were detected regarding gender, age of treatment or other risk factors. Global complication rate (p = 0.335, p = 0.225, p = 0.428) and clinical outcome (p = 0.802) was similar among both groups. Univariate and multivariate analysis revealed statistically significant differences between endovascular and surgical treatment groups regarding dome orientation (p = 0.011), aneurysm height (p < 0.001) and maximum diameter (p < 0.001), aspect-ratio (p < 0.001), dome-to-neck ratio (p < 0.001) and dome diameter (p = 0.014). Conclusions: Despite similar clinical outcomes and rate of complications, morphological differences highlight the presence of a selection bias and high heterogeneity, which hampers inferential analysis when comparing both techniques.

Giant Vertebrobasilar Aneurysm: The Rule of Decompressive Craniectomy Previous to Endovascular Treatment.

Giant vertebral-basilar aneurysms are rare and represent 1% of intracranial aneurysms. Natural history and treatment are associated with severe clinical manifestations, such as ischemia, mass effect, hydrocephalus, and subarachnoid hemorrhage, leading to high mortality and morbidity. In this case, a 51-year-old male with no relevant medical history presented to the emergency department with severe pulsatile right temporo-occipital headache, radiating to the territory of the maxillary branch of the trigeminal nerve. Investigation revealed a giant unruptured vertebrobasilar aneurysm partially thrombosed. As treatment strategy, a suboccipital craniectomy was initially performed, and a week later, as a second stage, the patient underwent a stent placement from the V3 segment of the vertebral artery to the distal segment of the basilar trunk. Very few cases of this entity have been reported, and the endovascular treatment of this type of aneurysm is complex, with a high risk of mortality or morbidity, caused by thrombosis or by the inflammatory response secondary to the treatment, with compression of the brainstem. Decompressive craniectomy prior to endovascular treatment may play an important role in preventing life-threatening complications.

The Importance of the Temporary Clip Removal Phase on Exposure to Hypoxia: On-Line Measurement of Temporal Lobe Oxygen Levels During Surgery for Middle Cerebral Artery Aneurysms.

BACKGROUND: Most studies concerning intraoperative temporary arterial occlusion overlook the period between and after clip placement. OBJECTIVE: To analyze the brain tissue oxygen tension through the process by which anterograde arterial blood flow is re-established after temporary clipping (TR). METHODS: In this prospective observational study, patients who presented to surgery for middle cerebral artery aneurysms were continuously monitored with ICM+, to obtain temporal (downstream) PbtO2 levels while M1 segment temporary clips were applied and removed. PbtO2 changes were analyzed and compared with the clipping phase, and measures of exposure to hypoxia were defined and assessed during both phases and used in a model to test the impact of extending them. RESULTS: Eighty-six TRs (20 patients) were recorded. The mean acquired amount of time per clip release (CR) event was 336.7 seconds. Temporary clip removal produced specifically shaped, highly individual PbtO2 curves that correlated with their corresponding clipping phase events but developing slower and less consistently. The CR phase was responsible for greater cumulative exposure to hypoxia than the clip application phase through the first and second minutes of each. In our model, the duration of the TR phase was mostly responsible for the total exposure to hypoxia, and longer CR phases reduced the mean exposure to hypoxia. CONCLUSION: During the clip removal phase, the brain tissue is still exposed to oxygen levels that are significantly below the baseline, reverting through a singular, dynamic process. Therefore, it must be regarded by surgeons with the same degree of attention as its counterpart.

Selection bias in patients proposed for neurosurgical versus endovascular treatment of aneurysms of the posterior communicating artery.

BACKGROUND: Microsurgical clipping and endovascular coiling are viable treatment options for posterior communicating artery (PComA) aneurysms, but there are still major limitations to evidence-based decisions regarding standard-of-care treatment. In this study, we aimed at assessing potential selection biases that may influence our ability to extract conclusions about the comparative effectiveness or efficacy of the aneurysm treatment. OBJECTIVE: To study the patient/aneurysm characteristics as possible biases in the option for endovascular or neurosurgical treatment of PComA aneurysms. METHODS: A single-center, retrospective cohort study was performed, including all patients with treated PComA aneurysms with neurosurgical clipping or endovascular coiling between January 2010 and January 2021. Clinical and morphological data were collected from electronic records, and statistical analysis was performed. RESULTS: A total of 64 patients was eligible for inclusion; 24 (37.5%) patients were proposed for neurosurgical treatment, while 40 (62.5%) for endovascular treatment; 10 patients (25%) crossed over to the clipping group whereas none crossed over to the coiling side. Actual treatment analysis showed significantly higher diameters of mother vessel (t-test, p = 0.034) and aneurysm neck (Mann-Whitney, p = 0.029) in the clipping group and higher aspect and dome-to-neck ratios in the endovascular group (Mann-Whitney, p = 0.008). A significantly higher vasospasm frequency was found in the clipping group but only in the intention-to-treat analysis (Chi-square, p = 0.032). CONCLUSION: Significant morphological differences between effective endovascular and surgical groups and differences in intention-to-treat analysis may limit the validity of a direct comparison between treatment options and suggest the presence of a possible selection bias.

Effects of Temporary Clipping as an Expression of Circulatory Individuality: Online Measurement of Temporal Lobe Oxygen Levels During Surgery for Middle Cerebral Artery Aneurysms.

OBJECTIVE: Despite its widespread use, much is left to understand about the repercussions of parent artery temporary clipping in neurosurgery. This study seeks a better comprehension of the subject by aiming at the online measurement of brain tissue oxygen pressure (PbtO2) during such events. METHODS: This was a prospective observational study. Patients submitted to surgery for middle cerebral artery aneurysms (both ruptured and unruptured) were continuously monitored under Intensive Care Monitoring+ software, in order to obtain temporal (downstream) PbtO2 levels while temporary clips were applied. Separate PbtO2 curve events were identified, extracted, and processed. These were studied for assessing intraindividual and interindividual variability and the potential impact of repeated clipping and previous aneurysmal rupture. RESULTS: Eighty-six temporary clippings (from 20 patients) were recorded with a mean duration of 140.8 (41 - 238) seconds. Temporary arterial occlusion at the M1 segment of the middle cerebral artery produced specifically shaped trajectories, characterized by a preclipping PbtO2 level, rapid downward sigmoid-shaped curve, succession of progressively angled slopes, and lower plateau. The steepest slope of the curve correlated strongly with PbtO2 range (P < 0.001, r = 0.944). These features were highly reproducible only intraindividually and did not vary significantly with repeated clippings. CONCLUSIONS: The effects of temporary arterial occlusion on temporal lobe oxygenation demonstrate a high degree of singularity, highlighting the potential benefits of assessing individual available collateral circulation intraoperatively. The "PbtO2 steepest slope" predicted the severity of PbtO2 decrease and was available within the first minute.

A wearable approach for intraoperative physiological stress monitoring of multiple cooperative surgeons.

It is known that excessive levels of occupational stress affect professionals' technical and non-technical skills and surgeons are no exception. However, very few studies address this problem in neurosurgeons. A system for monitoring cardiovascular strain and autonomic imbalance during intracranial aneurysm procedures is proposed in order to obtain overall cardiac measures from those procedures. Additionally, this study also allows to detect stressful events and compare their impact with the surgeon's own appraisal. Linear and nonlinear heart rate variability (HRV) features were extracted from surgeon's electrocardiogram (ECG) signal using wearable ECG monitors and mobile technology during 10 intracranial aneurysm surgeries with two surgeons. Stress appraisal and cognitive workload were assessed using self-report measures. Findings suggest that the surgeon associated to the main role during the clipping can be exposed to high levels of stress, especially if a rupture occurs (pNN20 = 0%), while the assistant surgeon tends to experience mental fatigue. Cognitive workload scores of one of the surgeons were negatively correlated with AVNN, SDNN, pNN20, pNN50, 1 V, 2 L V, SD2 and CVI measures. Cognitive workload was positively related with stress appraisal, suggesting that more mentally demanding procedures are also assessed as more stressful. Finally, pNN20 seems to better mirror behavior during stress moments than pNN50. Additionally, a sympathovagal excitation occurs in one of the professionals after changing to main role. The present methodology shows potential for the identification of harmful events. This work may be of importance for the design of effective interventions in order to reduce surgeons stress levels. Furthermore, this approach can be applied to other professions.

Anatomical variations of the vein of Labbé: an angiographic study.

PURPOSE: Little attention has been paid to the superficial anastomotic veins but severe post-operative complications can be related to iatrogenic venous damage. The importance of the position of VL (vein of Labbé) relates with the lateral accesses to skull base and medial tentorial lesions by posterior temporal approaches. The aim of this study was to characterize and deepen knowledge on the VL anatomy. METHODS: We reviewed retrospectively 101 hemispheres from cerebral angiographic studies in 59 patients (42 patients with bilateral angiography). RESULTS: VL duplication was found in 13 patients (31 %) and it was predominant on the left side. The absence of VL was rare (3 of 101 hemispheres). The mean location of the VL entry point in the transverse sinus was almost the middle of the distance between the inion and external acoustic meatus. The mean angle for this entry point was 69°. The mean VL caliber for the patients studied was 3.2 mm. Regarding the relation between VL and vein of Trolard, we found VL dominance in 31 % of the cases. About left-right intrapersonal variability we found a tendency for left VL dominance. CONCLUSIONS: We emphasized not only the interindividual differences but also the great intrapersonal variability of VL anatomy. The adequate study of the cerebral venous system particularities is of crucial importance for pre-operative planning to avoid severe complications.

Melanocitoma meníngeo intramedular dorsal / Thoracic spinal cord meningeal melanocytoma

O melanocitoma meníngeo é uma lesão infrequente, benigna, mas localmente agressiva. Sua localização intramedular é muito rara, existindo apenas três casos descritos na literatura. A propósito deste caso clínico, os autores reveem a literatura e discutem as características clínicas, imagiológicas e histológicas desse tipo de lesão. Relato do caso: Homem de 54 anos de idade com melanocitoma meníngeo intramedular dorsal (T11). Clinicamente apresentou, de início, disestesias torácicas, sem déficits neurológicos associados, que se mantiveram estáveis ao longo de dois anos. Após esse período teve instalação súbita de paraparesia. O diagnóstico definitivo foi estabelecido por exame histológico e imunocitoquímico após ressecção cirúrgica parcial da lesão. A pesquisa de melanoma maligno cutâneo--mucoso ou ocular foi negativa. Apesar de evolução inicial favorável apresentou recrescimento tumoral dois anos e meio após a primeira cirurgia, sendo reoperado. Apesar da ausência de complicações diretamente relacionadas com a cirurgia, acabou por falecer por sepsis na sequência de ruptura de diverticulite intestinal semanas depois.

Meningeal melanocytomas are infrequent, benign tumors but with a locally agressive behaviour. Extension to the spinal cord of these lesions is very rare and there are only three cases reported in the literature. The authors review the literature and discuss the clinical, neuroimaging and pathological features of this lesion. Case report: The authors present a case of a 54-year-old man with a thoracic spinal cord meningeal melanocytoma (T11). During two years the only complain was thoracic disestesias with no neurological deficit. After that period there was a sudden onset of paraparesia. The definitive diagnosis was made by histologic and immunocytochemical studies after parcial surgical excision of the lesion. No evidence of cutaneous, mucous or ocular malignant melanoma was found. Although an inicial favourable evolution, two and a half years after the first surgery the tumor regrowth and the patient was reoperated. No complications related to the surgery occurred but the patient had a rupture of an intestinal diverticulitis and died from sepsis some weeks later.

Tuberculosis disease - statistics of a paediatric department in the 21st century.

INTRODUCTION: Tuberculosis is a leading cause of world -wide mortality and morbidity. A reduced rate of tuberculosis in people aged less than 15 years has been seen in Portugal over the last decade of the twentieth century. MATERIAL AND METHODS: Retrospective analysis of tuberculosis cases in children admitted to the Centro Hospitalar de Vila Nova de Gaia January 1 2000 to December 31 2007. The individual epidemiological, clinical, radiological, microbiological and treatment information was analysed. RESULTS: We found 23 cases of tuberculosis disease (78% pulmonary tuberculosis and 22% extra- -pulmonary tuberculosis). Children's ages varied from 6 months to 16 years, with the male gender predominant. All patients had previously been vaccinated with BCG and there was a prior contact with TB in 57%. 2007 was the year with the highest number of cases. The Mantoux test was positive in 91% cases and M. tuberculosis isolation was possible in 61%. Gastric fluid analysis allowed isolation in 1/3 of cases and bronchoscopy contributed to M. tuberculosis isolation in 43% cases with negative gastric fluid analysis. Every patient underwent at least 6 months of tuberculostatic treatment, without any documented resistances. CONCLUSION: Tuberculosis remains a real problem, with the diagnosis, the search for contacts and adequate treatment (including prophylaxis) the main challenge.