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 authorized representative (LAR) 2. Stated willingness to comply with all study procedures and availability for the duration 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 hours of ictus hemorrhage 5. Disease-specific inclusion criteria: 1. Spontaneous, non-traumatic SAH 2. Subarachnoid pattern of hemorrhage warranting diagnostic DSA due to involvement of at least one of the following regions: quadrigeminal plate, prepontine cistern, perimesencephalic cistern, Sylvian fissure, or surrounding Circle of Willis 3. Modified Fisher grade 1-4 (on presentation imaging) 4. 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) 5. Minimum Glasgow Coma Scale verbal subscore of 4 (on screening) 6. 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 must meet all of the additional criteria: 7. Stabilization period criteria: 1. A minimum of 4 hours from DSA with clipping or coiling procedure (whenever applicable) 2. Successful treatment of culprit vascular lesion (i.e., ≥90% obliteration of aneurysm), when applicable 8. Requiring a minimum of 15mg OME prn for headache analgesia during any 24-hour period during eligibility period Exclusion Criteria: An individual who meets any of the following criteria will be excluded from participation in this study: 1. Premorbid conditions: 1. Pre-existing neurologic, psychiatric, or other condition that would confound neurologic assessment or would make difficult/impossible to accurately assess neurologic and/or functional outcome 2. Pre-existing diffuse flow-limiting narrowing of arteries in the Circle of Willis, regardless of etiology (e.g., atherosclerosis, vasculitis, Moya-Moya syndrome) 3. Prior use of opioid or barbiturate analgesics for at least two-thirds of the days in previous month, regardless of indication 4. Diagnosis of substance use disorder in the previous year 5. Infected or wounded skin, or a skin lesion at the site of puncture for PPF- injection 2. Uncorrected coagulopathy 1. Platelet count \< 50,000/μL, International Normalized Ratio (INR) \> 1.7 2. Requiring use of systemic anticoagulation and antiplatelet therapy (except for aspirin monotherapy). 3. SAH-specific: 1. Head trauma as etiology of SAH 2. Infection as cause for aneurysm or SAH (i.e., mycotic aneurysms) 3. Inability to successfully treat culprit vascular lesion 4. Diffuse vasospasm on pre-enrollment diagnostic CTA or DSA. Vasospasm is defined as moderate-to-severe arterial narrowing on DSA or CTA not attributable to atherosclerosis, catheter-induced spasm, or vessel hypoplasia, as determined by a neuroradiologist or neurointerventionalist 4. Standard pain regimen conditions 1. Elevation of hepatic enzymes prohibiting use of scheduled APAP (i.e., AST or ALT \> 3x upper limit level) 2. Chronic liver condition with absolute contra-indication for APAP (even at lower maximum daily doses) 5. Participation in a concurrent investigational/interventional study (observational studies allowed) 6. Known to be pregnant, or with a positive pregnancy test 7. Allergy or intolerance to the medications used in the PPF-block (i.e., ropivacaine, dexamethasone) or standard pain regimen (APAP) 8. Vulnerable populations such as prisoners and inmates (abiding GCP per the study IRB) 9. Unable to receive first PPF-injection within 96 hours of ictus hemorrhage