Evidence map›Paper›PMID 39138719›Full record

ArticleNeurocritical care2025

Rationale and Design for the BLOCK-SAH Study (Pterygopalatine Fossa Block as an Opioid-Sparing Treatment for Acute Headache in Aneurysmal Subarachnoid Hemorrhage): A Phase II, Multicenter, Randomized, Double-Blinded, Placebo-Controlled Clinical Trial with a Sequential Parallel Comparison Design.

Katharina M Busl, Cameron R Smith, Andrea B Troxel, Maurizio Fava, Nicholas Illenberger, Ralisa Pop, Wenqing Yang, Luciola Martins Frota, Hanzhi Gao, Guogen Shan and 3 more

Abstract readClinical Trial Protocol
PubMed Full text at PMC Publisher
In one paragraph

Article in Neurocritical care, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed.

  1. Trial
  2. Headache After Stroke: An Update for the Clinician.Current neurology and neuroscience reports · 2025
    Review
  3. Article
  4. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors.

Katharina M BuslDepartment of Neurology, College of Medicine, University of Florida, McKnight Brain Institute, L3-100, 1149 Newell Drive, Gainesville, FL, 32608, USA. k.busl@ufl.edu.ORCID 0000-0001-9961-0527
Cameron R SmithDepartment of Anesthesiology, College of Medicine, University of Florida, Gainesville, FL, USA.
Andrea B TroxelDepartment of Population Health, New York University Grossman School of Medicine, New York, NY, USA.
Maurizio FavaDepartment of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.
Nicholas IllenbergerDepartment of Population Health, New York University Grossman School of Medicine, New York, NY, USA.
Ralisa PopDepartment of Neurology, College of Medicine, University of Florida, McKnight Brain Institute, L3-100, 1149 Newell Drive, Gainesville, FL, 32608, USA.
Wenqing YangDepartment of Population Health, New York University Grossman School of Medicine, New York, NY, USA.
Luciola Martins FrotaDepartment of Neurology, College of Medicine, University of Florida, McKnight Brain Institute, L3-100, 1149 Newell Drive, Gainesville, FL, 32608, USA.
Hanzhi GaoDepartment of Biostatistics, University of Florida, Gainesville, FL, USA.
Guogen ShanDepartment of Biostatistics, University of Florida, Gainesville, FL, USA.
Brian L HohDepartment of Neurosurgery, College of Medicine, University of Florida, Gainesville, FL, USA.
Carolina B MacielDepartment of Neurology, College of Medicine, University of Florida, McKnight Brain Institute, L3-100, 1149 Newell Drive, Gainesville, FL, 32608, USA.
BLOCK-SAH Investigators

Funding

Pterygopalatine Fossa (PPF) Block as an Opioid Sparing Treatment for AcuteHeadache in Aneurysmal Subarachnold HemorrhageU01NS124613 · NINDS · UNIVERSITY OF FLORIDA · PI Katharina Maria Busl, Brian Lim Hoh · 2023 to 2026
$10.5M
Robust Computational and Data Analytic Tools for In-depth Understanding Postoperative Pain Mechanism with Enhanced Pain Management and Clinical Decision MakingR01LM014407 · NLM · UNIV OF NORTH CAROLINA CHAPEL HILL · PI Baiming Zou · 2024 to 2026
$1.4M
NINDS NIH HHS U01 NS124613NINDS NIH HHS U01NS124613NLM NIH HHS R01 LM014407
6 · The paper itself

Abstract

backgroundAcute post-subarachnoid hemorrhage (SAH) headaches are common and severe. Management strategies for post-SAH headaches are limited, with heavy reliance on opioids, and pain control is overall poor. Pterygopalatine fossa (PPF) nerve blocks have shown promising results in treatment of acute headache, including our preliminary and published experience with PPF-blocks for refractory post-SAH headache during hospitalization. The BLOCK-SAH trial was designed to assess the efficacy and safety of bilateral PPF-blocks in awake patients with severe headaches from aneurysmal SAH who require opioids for pain control and are able to verbalize pain scores.

methodsBLOCK-SAH is a phase II, multicenter, randomized, double-blinded, placebo-controlled clinical trial using the sequential parallel comparison design (SPCD), followed by an open-label phase.

resultsAcross 12 sites in the United States, 195 eligible study participants will be randomized into three groups to receive bilateral active or placebo PPF-injections for 2 consecutive days with periprocedural monitoring of intracranial arterial mean flow velocities with transcranial Doppler, according to SPCD (group 1: active block followed by placebo; group 2: placebo followed by active block; group 3: placebo followed by placebo). PPF-injections will be delivered under ultrasound guidance and will comprise 5-mL injectates of 20 mg of ropivacaine plus 4 mg of dexamethasone (active PPF-block) or saline solution (placebo PPF-injection).

conclusionsThe trial has a primary efficacy end point (oral morphine equivalent/day use within 24 h after each PPF-injection), a primary safety end point (incidence of radiographic vasospasm at 48 h from first PPF-injection), and a primary tolerability end point (rate of acceptance of second PPF-injection following the first PPF-injection). BLOCK-SAH will inform the design of a phase III trial to establish the efficacy of PPF-block, accounting for different headache phenotypes.

Indexed as

Anesthetics, LocalHeadacheNerve BlockPterygopalatine FossaSubarachnoid HemorrhageAdultAnalgesics, OpioidClinical Trials, Phase II as TopicDouble-Blind MethodFemaleHumansMaleMiddle AgedMulticenter Studies as TopicRandomized Controlled Trials as TopicAnalgesics, OpioidAnesthetics, LocalHeadacheIntensive careNerve blockOpioid analgesicsSubarachnoid hemorrhage

Identifiers

PMID39138719
PMCPMC11810580

What OpenQuestion holds

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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.