The small trial problem.

BACKGROUND: Many randomized trials that aim to assess new or commonly used medical or surgical interventions have been so small that the validity of conclusions becomes questionable. METHODS: We illustrate the small trial problem using the power calculation of five Cochrane-reviewed studies that compared vertebroplasty versus placebo interventions. We discuss some of the reasons why the statistical admonition not to dichotomize continuous variables may not apply to the calculation of the number of patients required for trials to be meaningful. RESULTS: Placebo-controlled vertebroplasty trials planned to recruit between 23 and 71 patients per group. Four of five studies used the standardized mean difference of a continuous pain variable (centimeters on the visual analog scale (VAS)) to plan implausibly small trials. What is needed is not a mean effect at the population level but a measure of efficacy at the patient level. Clinical practice concerns the care of individual patients that vary in many more respects than the variation around the mean of a single selected variable. The inference from trial to practice concerns the frequency of success of the experimental intervention performed one patient at a time. A comparison of the proportions of patients reaching a certain threshold is a more meaningful method that appropriately requires larger trials. CONCLUSION: Most placebo-controlled vertebroplasty trials used comparisons of means of a continuous variable and were consequently very small. Randomized trials should instead be large enough to account for the diversity of future patients and practices. They should offer an evaluation of a clinically meaningful number of interventions performed in various contexts. Implications of this principle are not specific to placebo-controlled surgical trials. Trials designed to inform practice require a per-patient comparison of outcomes and the size of the trial should be planned accordingly.

The impact of previous health on the mortality after aneurysmal subarachnoid hemorrhage: analysis of a prospective Swedish multicenter study.

PURPOSE: There is an an increasing awareness of the importance of health and lifestyle for stroke diseases like spontaneous subarachnoid hemorrhage (SAH). However, the importance of pre-existing medical conditions for clinical course and mortality after SAH has not been studied. The aim of the present study was to identify pre-existing conditions contributing to mortality after SAH. METHODS: Data were extracted from a Swedish national prospective study on patients with SAH. Variables were defined for age, sex, body mass index (BMI), clinical condition at admission, and for 10 pre-existing medical conditions. Models predicting mortality in three time intervals with all possible subsets of these variables were generated, compared and selected using Akaike's information criterion. RESULTS: 1155 patients with ruptured aneurysms were included. The mortality within 1 week was 7.6%, 1 month 14.3%, and 1 year 18.7%. The most common pre-existing medical conditions were smoking (57.6%) and hypertension (38.7%). The model's best predicting mortality within 1 week and from 1 week to 1 month included only the level of consciousness at admission and age, and these two variables were present in all the models among the top 200 in Akaike score for each time period. The most predictive model for mortality between 1 month and 1 year added previous stroke, diabetes, psychiatric disease, and BMI as predictors. CONCLUSION: Mortality within the first month was best predicted simply by initial level of consciousness and age, while mortality within from 1 month to 1 year was significantly influenced by pre-existing medical conditions.

Recruitment in a Pragmatic Randomized Trial on the Management of Unruptured Intracranial Aneurysms.

OBJECTIVES: The Comprehensive Aneurysm Management (CAM) study is a pragmatic trial designed to manage unruptured intracranial aneurysm (UIA) patients within a care research framework. METHODS: CAM is an all-inclusive study. Management options are allocated according to an algorithm combining pre-randomization and clinical judgment. Eligible patients are offered 1:1 randomized allocation of intervention versus conservative management and 1:1 randomization allocation of surgical versus endovascular treatment. Ineligible patients are registered. The primary outcome is survival without dependency (modified Rankin Scale score <3) at 10 years. All UIA patients at 1 center are reported. RESULTS: Between February 2020 and July 2021, 403 UIA patients were recruited: 179 (44%) in one of the randomized controlled trials (RCTs) and 224 (56%) in one of the registries. Conservative management was recommended for 205 of 403 patients (51%); of 198 (49%) patients considered for curative treatment, 159 (80%) were randomly allocated conservative (n = 81) or curative treatment (n = 78). These patients were younger and had larger aneurysms than those in the observation registry (P = 0.004). In 39 of 198 patients (20%), conservative management was not considered reasonable (17 patients were recommended endovascular, 2 surgery, and 20 the RCT comparing endovascular with surgical treatment). In total, 70 patients were recruited in the RCT comparing surgery and endovascular treatment. After informed discussion at time of consent, 141 of 159 patients (89%) agreed with the randomly allocated management plan, while 11% crossed over to the alternative management option. CONCLUSIONS: CAM was successfully integrated into routine practice. Meaningful conclusions can be obtained if multiple centers actively participate in the trial.

Three-month functional outcomes following endovascular thrombectomy during the first wave of the COVID-19 pandemic: a Canadian single-center cohort study.

BACKGROUND: The COVID-19 pandemic has disrupted acute stroke care logistics, including delays in hyperacute management and decreased monitoring following endovascular therapy (EVT). We aimed to assess the impact of the pandemic on 90-day functional outcome among patients treated with EVT. METHODS: This is an observational cohort study including all patients evaluated for an acute stroke between March 30, 2020 and September 30, 2020 (pandemic cohort) and 2019 (reference cohort) in a high-volume Canadian academic stroke center. We collected baseline characteristics, acute reperfusion treatment and management metrics. For EVT-treated patients, we assessed the modified Rankin score (mRS) at 90 days. We evaluated the impact of the pandemic on a 90-day favourable functional status (defined as mRS 0-2) and death using multivariable logistic regressions. RESULTS: Among 383 and 339 patients included in the pandemic and reference cohorts, baseline characteristics were similar. Delays from symptom onset to evaluation and in-house treatment were longer during the early first wave, but returned to reference values in the subsequent months. Among the 127 and 136 EVT-treated patients in each respective cohort, favourable 90-day outcome occurred in 53/99 (53%) vs 52/109 (48%, p=0.40), whereas 22/99 (22%) and 28/109 (26%, p=0.56) patients died. In multivariable regressions, the pandemic period was not associated with 90-day favourable functional status (aOR 1.27, 95% CI 0.60 to 2.56) or death (aOR 0.74, 95% CI 0.33 to 1.63). CONCLUSION: In this single-center cohort study conducted in a Canadian pandemic epicenter, the first 6 months of the COVID-19 pandemic did not impact 90-day functional outcomes or death among EVT-treated patients.

Sphenopalatine arteriovenous fistula complicating transsphenoidal pituitary surgery: A rare cause of delayed epistaxis treatable by endovascular embolization.

BACKGROUND: Vascular injuries in transsphenoidal surgery for pituitary adenomas are uncommon but can result in serious disability or death. CASE DESCRIPTION: A 46-year-old man, who underwent resection of a pituitary adenoma with suprasellar extension via a transsphenoidal approach, presented with massive epistaxis five days postoperatively. Angiography revealed an arteriovenous fistula (AVF) between the right sphenopalatine artery and a deep vein draining to the right internal jugular vein, as well as contrast agent extravasation at the fistula point. The AVF was catheterized and successfully occluded with N-butyl-2-cyanoacrylate. CONCLUSIONS: Transsphenoidal pituitary surgery can be complicated by massive epistaxis from a lesion of a small branch of the external carotid artery. Airway protection through intubation and investigation with conventional digital subtraction angiography is recommended. The treatment of choice is endovascular embolization because it can be done immediately at the angiography suite.

A treatment-refractory spinal dural arteriovenous fistula sharing arterial origin with the Artery of Adamkiewicz: Repeated endovascular treatment after failed microsurgery.

BACKGROUND: Effective management of a spinal dural arteriovenous fistula (SDAVF) can be accomplished with either microsurgery or endovascular embolization, but there is a consensus that in patients in whom a radiculomedullary artery supplying the anterior spinal artery (ASA) originates from the same feeding artery as the SDAVF, the endovascular approach is to be avoided. CASE DESCRIPTION: The patient was a 46-year-old woman with progressive lower limb paraparesis, sensory deficit, and sphincter dysfunction. Magnetic resonance imaging (MRI) and spinal angiography showed an SDAVF fed by a branch from the left second lumbar segmental artery, and the artery of Adamkiewicz (AA), a major ASA supplier, originating from the same segmental artery just proximal to the SDAVF. Microsurgical disconnection of the SDAVF was attempted, but failed. Embolization with cyanoacrylates was done in two occasions, the first time through a microcatheter placed just distal to the origin of the AA and the second time through another feeder coming from the same segmental artery that could not be visualized in the previous angiographies. All procedures were neurologically uncomplicated. Magnetic resonance imaging (MRI) 1 month after the last embolization showed resolution of the spinal cord edema. MRI scan taken 68 months after embolization revealed a slightly atrophic spinal cord with visible central canal and no recurrence of medullary edema. The patient presented good, but incomplete neurological improvement. CONCLUSION: Microsurgery is the first choice for an SDAVF branching off the same radiculomedullary artery supplying the ASA, but uncomplicated embolization can be feasible after failed surgery.