BLOCK-SAH - PPF-Block for Post-SAH Headache

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

1. Provision of signed and dated ICF by participant or a legally authorizedrepresentative (LAR)

2. Stated willingness to comply with all study procedures and availability for theduration of the study

3. Male or female, aged ≥18 and ≤ 85 years

4. Admitted with a primary diagnosis of spontaneous, non-traumatic, SAH within 72 hoursof ictus hemorrhage

5. Disease-specific inclusion criteria:

6. Spontaneous, non-traumatic SAH

7. Subarachnoid pattern of hemorrhage warranting diagnostic DSA due to involvementof at least one of the following regions: quadrigeminal plate, prepontinecistern, perimesencephalic cistern, Sylvian fissure, or surrounding Circle ofWillis

8. Modified Fisher grade 1-4 (on presentation imaging)

9. Hunt and Hess 1-3 or World Federation of Neurosurgeons grade 1-4 (on screening,included only if also fulfilling Glasgow Coma Scale verbal subscore ≥4)

10. Minimum Glasgow Coma Scale verbal subscore of 4 (on screening)

11. Able to verbalize pain scale scores according to 11-point numeric pain scale In order to be enrolled and undergo randomization in this study, an individual mustmeet all of the additional criteria:

12. Stabilization period criteria:

13. A minimum of 4 hours from DSA with clipping or coiling procedure (wheneverapplicable)

14. Successful treatment of culprit vascular lesion (i.e., ≥90% obliteration ofaneurysm), when applicable

15. Requiring a minimum of 15mg OME prn for headache analgesia during any 24-hour periodduring eligibility period

Exclusion Criteria:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Premorbid conditions:

2. Pre-existing neurologic, psychiatric, or other condition that would confoundneurologic assessment or would make difficult/impossible to accurately assessneurologic and/or functional outcome

3. Pre-existing diffuse flow-limiting narrowing of arteries in the Circle ofWillis, regardless of etiology (e.g., atherosclerosis, vasculitis, Moya-Moyasyndrome)

4. Prior use of opioid or barbiturate analgesics for at least two-thirds of thedays in previous month, regardless of indication

5. Diagnosis of substance use disorder in the previous year

6. Infected or wounded skin, or a skin lesion at the site of puncture for PPF-injection

7. Uncorrected coagulopathy

8. Platelet count < 50,000/μL, International Normalized Ratio (INR) > 1.7

9. Requiring use of systemic anticoagulation and antiplatelet therapy (except foraspirin monotherapy).

10. SAH-specific:

11. Head trauma as etiology of SAH

12. Infection as cause for aneurysm or SAH (i.e., mycotic aneurysms)

13. Inability to successfully treat culprit vascular lesion

14. Diffuse vasospasm on pre-enrollment diagnostic CTA or DSA. Vasospasm is definedas moderate-to-severe arterial narrowing on DSA or CTA not attributable toatherosclerosis, catheter-induced spasm, or vessel hypoplasia, as determined bya neuroradiologist or neurointerventionalist

15. Standard pain regimen conditions

16. Elevation of hepatic enzymes prohibiting use of scheduled APAP (i.e., AST orALT > 3x upper limit level)

17. Chronic liver condition with absolute contra-indication for APAP (even at lowermaximum daily doses)

18. Participation in a concurrent investigational/interventional study (observationalstudies allowed)

19. Known to be pregnant, or with a positive pregnancy test

20. Allergy or intolerance to the medications used in the PPF-block (i.e., ropivacaine,dexamethasone) or standard pain regimen (APAP)

21. Vulnerable populations such as prisoners and inmates (abiding GCP per the study IRB)

22. Unable to receive first PPF-injection within 96 hours of ictus hemorrhage