Headaches such as tension-type, migraine, and cervicogenic (neck-related) headaches are among the most common and disabling conditions worldwide. and are often associated with tight or sensitive muscles at the base of the skull, which can contribute to headaches. Dry needling involves inserting a very thin, sterile needle into tight muscle areas known as trigger points to relieve pain and muscle tension. When applied to the deep neck muscles, including those beneath the skull, dry needling may reduce headache symptoms. The suboccipital region contains important structures such as the vertebral artery, greater occipital nerve, and spinal cord, which requires precise needle placement to maintain safety. Many needling techniques used in this region have not been validated for accuracy or safety in living subjects. This study will use real-time ultrasound imaging to guide dry needling of the rectus capitis posterior major muscle and directly visualize nearby structures to minimize risk.

The main goals of this research are to examine the effects of a single session of ultrasound-guided dry needling on headache symptoms and to confirm the safety, accuracy, and consistency of the proposed needling technique using ultrasound imaging.

RESEARCH DESIGN: Prospective, single-arm, repeated-measures interventional study with secondary observational ultrasound validation of two insertion angles and intra-rater test-retest reliability of ultrasound assessments at ~6 months.

PROCEDURE: Each participant will complete one study visit lasting approximately 60 minutes. During each data collection session:

1. Screening: Participants will undergo screening for inclusion and exclusion criteria.

   o Eligible participants will then complete: A Numeric Pain Rating Scale (NPRS) of their headache pain on a scale from 0 to 10 (0 = no pain; 10 = worse pain) including: Current rating; Best rating; Worst rating in the past 6 months; Complete the Headache Disability Index (HDI)

2. Positioning: Participants will be positioned prone on a treatment table with cervical spine alignment monitored using an inclinometer to ensure cervical lordosis is under 10°.

3. Landmark Identification & Needle Insertion:

   • Landmark Identification: The PI will palpate and mark two bony landmarks in the upper neck including: 1. The C2 Spinous process, a distinct bone that can be felt at the top of the spine below the skull, and 2. The C1 Transverse process, a bony ridge located just below and slightly to the side of the base of the skull at ~45-degree angle from the ear. (These landmarks will help determine the correct location for the needle insertion.)
   • Needle Insertion: Sterile, 0.25 gauge/diameter, 40 mm needles will be used. A new needle will be used for each individual needle insertion before being discarded in a sharps container. The needle will be inserted just below the base of the skull, slightly off the center line of the neck. Each participant will have two separate needle insertions during the single data collection visit. Two dry needle insertion techniques will be performed in a randomized order: Method 1: 30° (relative to the frontal plane) insertion angle toward the occiput, and Method 2: 45° (relative to the frontal plane) insertion angle toward the occiput.
   • Needle Target: The target of the needle is a deep muscle (Rectus Capitus Posterior Major) that attaches to the base of the skull (occiput). For both methods, the needle will be advanced until bony contact is achieved, and then slightly pulled in/out within the muscle to visualize needle placement on ultrasound
   • Randomization of technique order (Method 1 vs. Method 2) will be generated using the list randomizer from https://www.random.org/lists/

4. Ultrasound Imaging: An investigator will use a Sonosite PX ultrasound device to capture still images and 3-second video clips of needle placement relative to the RCPMaj and surrounding anatomy. Participants may be asked to laterally deviate their eyes to assist in muscle visualization.

5. Data Collection: Investigators will record whether a bony backdrop was felt, if the needle reached the RCPMaj, and the length of unused needle remaining outside the skin as well as if the needle pierce through the vertebral artery.

IMMEDIATE POST-PROCEDURE: Participants will be asked to rate their current level of pain immediately following the intervention on the NPRS from 0 to 10 (0 = no pain; 10 = worse pain)

POST-PROCEDURE FOLLOW UP VISIT: 24-48 hours following data collection, participants will be asked to complete the following via a secure, anonymous online survey link to the electronic platform Qualtrics®. Participants will be sent an email with the secure survey link and reminder of their unique study ID. Participants will only use their unique assigned study ID. No identifying information (name, email address, or IP address) will be collected in Qualtrics® survey responses. Participants will report: 1) Post-needling soreness (Yes/No), 2) NRPS including Current rating, Best rating and Worst rating in the last 24-48 hours, and 3) Headache Disability Index

Inclusion Criteria:

• Reports of a headache within the last 6 months (no minimum or maximum frequency or duration)
• Current reports of headache
• Tenderness to palpation of suboccipital muscles with Numeric Pain Rating Scale score ≥ 2/10
• No history of cervical spine surgery or neurological disorders

Exclusion Criteria:

• History of cervical spine trauma or surgery
• Diagnosed bleeding disorder
• Currently using anticoagulant medications
• Currently using anti-platelet medications
• Diagnosed systemic joint diseases such as rheumatoid arthritis
• Active infection
• Diabetes
• Cancer
• Fibromyalgia
• Cervical radiculopathy
• Inability to tolerate prone positioning for the duration of the procedure.

There is no need to share IPD with other investigators. Once completed, there will be no need to access any IPD in the future.