Nerve Block Anesthesia Combined With Sedative Anesthesia Versus General Anesthesia in Surgery for CSDH

Nerve Block Anesthesia Combined With Sedative Anesthesia Versus General Anesthesia in Surgery for CSDH

Safety and Efficacy of Nerve Block Anesthesia Combined With Sedative Anesthesia Versus General Anesthesia in Burr Hole Craniostomy With Drainage for Chronic Subdural Hematoma

A prospective, multicenter, randomized controlled trial is designed to evaluate the safety and efficacy of nerve block anesthesia combined with sedative anesthesia versus general anesthesia during burr hole craniostomy with drainage for chronic subdural hematoma.

Chronic subdural hematomas (CSDHs) are one of the most common neurosurgical conditions. The standard surgical technique includes burr-hole craniotomy, followed by intraoperative irrigation and placement of subdural closed-system drainage. Both general anesthesia and local anesthesia can be used for the surgical treatment of CSDH. CSDH is more common among elderly patients, who also have associated comorbidities and thus, are at increased risk of perioperative complications, especially under general anesthesia. Moreover, general anesthesia may lead to an increased incidence of postoperative delirium (POD) in neurosurgery patients, especially in elderly patients with a high incidence of CSDH. However, intraoperative movement in local anesthesia may lead to catastrophic outcomes. Dexmedetomidine is an α2-adrenergic agonist with low incidence of respiratory depression but easy arousal. Dexmedetomidine could provide sufficient analgesia to prevent intraoperative body movements and improve the satisfaction of surgeons and patients. In the meanwhile, it was suggested that dexmedetomidine can reduce the incidence of POD in neurosurgery without significantly increasing the incidence of other intra- and postoperative complications. The primary objective of this study is to compare the safety and efficacy of nerve block anesthesia combined with dexmedetomidine sedation versus general anesthesia for the surgical evacuation of CSDH, and investigate whether nerve block anesthesia combined with dexmedetomidine sedation will improve the occurrence of POD but not increase the incidence of intraoperative body movement.

Chronic Subdural Hematoma, Nerve Block Anesthesia, Sedative Anesthesia, General Anesthesia, Burr Hole Craniostomy, Drainage

The investigators design to mask only the outcome assessors for intra- and postoperative follow-up evaluation, and data analysts. Before the outcome assessment begins at every follow-up evaluation, the patients will be reminded not to reveal any information about their group allocation. If details of group allocation were revealed by participants during follow-ups, another blinded outcome assessor will take over the assessment for these participants.

Under monitored anesthesia care, general anesthesia with propofol or etomidate are administered, and burr hole craniostomy is performed.

Under monitored anesthesia care, 0.5% ropivacaine and 1% lidocaine are administered to block the auricularis temporal, greater and lesser occipital nerves, combined with dexmedetomidine intravenous infusion for sedation, and burr hole craniostomy is performed.

Patients will firstly receive cranial nerve blocks (ipsilateral auriculotemporal, greater occipital nerve, and lesser occipital nerve block) with 1.5ml~2.0ml 0.5% ropivacaine and 1% lidocaine at each site under standard monitoring. At the same time, intravenous dexmedetomidine infusion will be initiated for sedation at a rate of 2-4ug/kg for 10 minutes, followed by a continuous infusion of 0.5 to 1ug/kg/h until the end of the operation. The responsible anesthesiologist could adjust the rate of infusion according to the patient's physical condition. The bispectral index value will be maintained around 60 to 70 via adjusting the infusion of dexmedetomidine.

General anesthesia patients are preoxygenated for 6 min, and standardized anesthesia induction is initiated with propofol 1-2mg/kg or etomidate 0.15mg/kg-0.4mg/ kg, sufentanil 0.2-0.3ug/kg, rocuronium 0.6mg/kg or cisatracuronium 0.2mg/kg for induction. Anesthesia is maintained by total intravenous anesthesia, and intraoperative bispectral index monitoring is maintained between 40 and 60. H3 receptor blocker is given before the end of surgery to prevent nausea and vomiting.

A single 1.5 cm burr hole is drilled over the maximum width of the hematoma cavity. After coagulating with bipolar diathermy, dura mater is opened with a cruciate incision. A soft catheter is placed carefully in all directions of the hematoma cavity for irrigating subdural collections with 1,000 mL warm Ringer's lactate saline until clarification. The drainage catheter is inserted ½ length of the maximum diameter of the hematoma cavity toward the frontal region. After the skin is closed, the catheter is connected to a soft collection bag that is placed under the head for passive drainage. During the drainage period, participants stay in bed until the drain is removed.

Postoperative delirium is assessed twice a day (08:00-09:00 and 16:00-17:00) by the combination of the Richmond Anxiety Scale (RASS) and the Confusion assessment method for intensive care unit (CAM-ICU) or the 3-minute diagnostic interview for CAM (3D-CAM) as applicable. Delirium consists of four main characteristics: acute onset of a change in mental status or a fluctuating level of consciousness, inattention, disorganized thinking and an altered level of consciousness. The patient was diagnosed as delirious if both the first and second features were present, and either the third or fourth was present. In the ICU, the arousal level was first assessed by RASS. If the patient was not responsive to verbal stimuli (i.e. RASS score ≤-4), the remaining delirium assessment was aborted, and the patient was recorded as comatose. When the RASS score was greater than or equal to 3, delirium was evaluated using the CAM-ICU. Patients in general ward were evaluated by 3D-CAM.

The primary safety outcome is the incidence of intraoperative body movement. Intraoperative body movement is defined as those likely to interfere with surgical procedure such as bending of hand and/or leg and movement of head. Tiny movement of body parts or movements of finger or toes are not deemed significant enough to record for the purpose of this study as they are unlikely to be of hindrance to the successful conduct of surgical procedure.

Modified Rankin Scale ranges from score 1 to 6, and higher scores mean a worse clinical outcome, where score 1 indicates normal daily functionality and score 6 indicates death.

Markwalder Grading Scale ranges from grade 0 to 4, and higher scores mean a worse neurological outcome, where grade 0 indicates normal neurological function and grade 4 indicates coma.

Non-delirium complications are defined as new-onset medical events other than delirium that are harmful to patients' recovery and required therapeutic intervention.

For the nerve block anesthesia combined with sedative anesthesia group, general anesthesia is performed if uncontrolled body movements still exist after opioid and sedative supplement.

Pain after surgery is evaluated by Numerical Rating Scale (NRS). The NRS is a validated 11-point numerical scale that ranges from 0 (no pain) to 10 (worst pain possible).

A 7-point Likert-like verbal rating scale is performed for the assessment of patients' and surgeons' satisfaction with intraoperative analgesia, with higher score indicating better satisfaction.

Recovery assessment is assessed with the quality of recovery-15 (QoR-15), a 15-item questionnaire that provides an assessment of cognitive function, physical activity, linguistic ability, and emotion. The score ranges from 0 to 150, with higher score indicating better function.

Tension pneumocephalus is defined as pneumocephalus which has space-occupying effect and brain displacement.

Inclusion Criteria: Patient (18 years to 80 years) presenting with clinical symptoms and neurological deficits of chronic subdural hematoma Chronic subdural hematoma verified on cranial computed tomography or magnetic resonance imaging with hematoma width maximum ≥1.0cm or midline shift ≥1.0cm Propose to perform burr hole craniostomy Written informed consent from patients or their next of kin according to the patient's cognitive status Exclusion Criteria: Preoperative significant disturbance of consciousness or cognitive impairment (Glasgow Coma Scale<13, or Markwalder Grade 2-4, or Mini-Cog≤3, or MMSE≤20) Preoperative presence of sensory or motor aphasia patients, unable to understand and cooperate with anesthesia Recurrence of hematoma with previous surgery for chronic subdural hematoma. Previous intracranial surgery Existing severe intracranial lesion, poor medication condition or severe comorbidity Allergic history of anesthetics Severe coagulopathy or high risk of life-threatening bleeding Participating in another research

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