An interventional study of Ultrasound-Guided Bilateral Greater Occipital Nerve Block and Bilateral Superficial Subcutaneous Sham Injection in Intracranial Aneurysm and Postoperative Pain, sponsored by Konya City Hospital. Not yet recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-11-02.
Sponsored by Konya City Hospital · Not applicable, Interventional, and Prevention
Postoperative headache is a common complication following endovascular coil embolization of intracranial aneurysms and may increase analgesic requirements, impair patient comfort, and contribute to hemodynamic instability.
The greater occipital nerve (GON) has anatomical and functional connections with the trigeminocervical complex, suggesting that greater occipital nerve blockade may modulate headache-related pain pathways. However, the effectiveness of prophylactic greater occipital nerve block in patients undergoing elective endovascular coiling of unruptured intracranial aneurysms remains uncertain.
This prospective, randomized, sham-controlled, single-center clinical trial aims to investigate whether preoperative ultrasound-guided bilateral greater occipital nerve block reduces postoperative headache intensity during the first 24 hours following endovascular coil embolization.
A total of 76 patients will be randomly allocated in a 1:1 ratio to receive either ultrasound-guided bilateral greater occipital nerve block with 0.25% bupivacaine or bilateral superficial sham injections with 0.9% normal saline.
The active intervention will consist of 3 mL of 0.25% bupivacaine administered on each side in the fascial plane between the semispinalis capitis and obliquus capitis inferior muscles. The control intervention will consist of a superficial subcutaneous injection of 0.5 mL of 0.9% normal saline on each side.
All participants will receive standardized general anesthesia and postoperative multimodal analgesia.
The primary outcome will be the time-weighted average resting pain score during the first 24 postoperative hours, calculated from the area under the Numeric Rating Scale (NRS) pain score-time curve.
418 studies on the registry are indexed under Intracranial Aneurysm; 119 are open to participants now.
This study's planned enrollment of 76 is below the median of 100 across 207 interventional studies indexed under Intracranial Aneurysm.
Browse Intracranial Aneurysm studies →Konya City Hospital is the lead sponsor of 81 studies on the registry; 23 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
INR, PT and aPTT (clotting tests)
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants assigned to the experimental group will receive preoperative ultrasound-guided bilateral greater occipital nerve block with 0.25% bupivacaine before induction of general anesthesia. A total of 3 mL of 0.25% bupivacaine (7.5 mg) will be administered on each side into the interfascial plane between the semispinalis capitis and obliquus capitis inferior muscles. The total bilateral dose will be 15 mg of bupivacaine in 6 mL. The intervention will be performed while the patient is awake and able to communicate, without routine deep sedation. All participants will subsequently receive standardized general anesthesia and postoperative multimodal analgesia.
Procedure: Ultrasound-Guided Bilateral Greater Occipital Nerve Block
Participants assigned to the control group will receive bilateral superficial subcutaneous sham injections with 0.9% normal saline before induction of general anesthesia. Following the same general preparation, positioning, and ultrasound examination as the experimental group, 0.5 mL of 0.9% normal saline will be injected subcutaneously on each side of the occipital region using a short 27-gauge needle. The total bilateral injection volume will be 1 mL. The needle will not be advanced into the deep interfascial plane, and no injection will be performed around the greater occipital nerve. All participants will receive standardized general anesthesia and postoperative multimodal analgesia.
Procedure: Bilateral Superficial Subcutaneous Sham Injection
Ultrasound-guided bilateral greater occipital nerve block will be performed before general anesthesia induction using a high-frequency linear ultrasound transducer. The greater occipital nerve will be identified between the semispinalis capitis and obliquus capitis inferior muscles. A 25-gauge, 50-mm echogenic needle will be advanced under continuous ultrasound guidance using an in-plane approach. Following color Doppler assessment and negative aspiration, 3 mL of 0.25% bupivacaine (7.5 mg) will be injected slowly and incrementally on each side. The total bilateral dose will be 15 mg of bupivacaine.
A bilateral superficial subcutaneous sham injection will be performed before general anesthesia induction. Following standardized positioning, skin antisepsis, and ultrasound examination, a short 27-gauge needle will be used to administer 0.5 mL of 0.9% normal saline subcutaneously on each side of the occipital region. The total bilateral injection volume will be 1 mL. The needle will not be advanced into the deep interfascial plane, and the greater occipital nerve will not be directly targeted.
Time-Weighted Average Resting Pain Score During the First 24 Postoperative Hours
Postoperative resting pain intensity will be assessed using the 11-point Numeric Rating Scale (NRS), ranging from 0 (no pain) to 10 (worst imaginable pain). NRS scores will be recorded at postoperative hours 0, 2, 4, 6, 8, 12, and 24. The area under the NRS pain score-time curve (AUC0-24) will be calculated using the linear trapezoidal method and divided by 24 hours to obtain the time-weighted average NRS score. The resulting patient-level value will range from 0 to 10, with higher scores indicating greater overall postoperative pain intensity.
Time frame: From postoperative hour 0 to postoperative hour 24
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Konya City Hospital