Ultrasound Guided Trigeminal Nerve Block in Maxillofacial Surgeries

Evaluating the Perioperative Analgesic Effect of Ultrasound-guided Trigeminal Nerve Block in Adult Patients Undergoing Maxillo-facial Surgery Under General Anesthesia: A Randomized Controlled Study

This study aims to evaluate the perioperative analgesic effect of USG Trigeminal Nerve Block in adult patients undergoing maxillofacial surgery. We hypothesized that giving USG-guided TNB in patients undergoing maxilla-facial surgery could reduce the requirements of opioids perioperatively and avoid the side effects of opioids used.

The aim of this double-blind study is to evaluate the effect of USG-guided TNB intra- and post-operatively in terms of pain relief, opioid consumption and adverse effects in patients undergoing such elective surgeries.

Nerve block using various agents has been proposed as a part of the multimodal analgesia to decrease consumption of intravenous opioids and also decrease its complications such as respiratory depression. Recent research has focused on the role of trigeminal nerve blocks (TNB) for management of facial pain . This block was found to be effective in trigeminalneuralgia , palate surgeries and oral and dental surgeries.

Anatomically, the Gasserian ganglion lies in the middle cranial fossa within the Meckel's cave and gives rise to three branches (1) ophthalmic, (2) maxillary, and (3) mandibular which exit from skull through three distinct foramina: the superior orbital fissure, the foramen rotundum, and the foramen ovale. The injection anterior and medial to lateral pterygoid plate into the upper part of pterygopalatine fossa (PPF) will place the injectate in close vicinity to foramen rotundum from where drug migrates into the middle cranial fossa. Since the PPF is extremely vascular, visualizing vascular and soft tissue structures in real time minimize the potential inadvertent complications.

Fluoroscopy-guided blocks have long been considered the gold standard practice in head and neck pain management. Alternatively, computed tomography-guided procedures provide a useful option but expensive and have radiation hazard. Lately, ultrasonography (USG) has been used extensively for perioperative pain relief providing excellent visualization of soft tissue and vasculature with real-time needle placement.

To date, very few published studies had evaluated the value of USG-guided TNB for control of perioperative pain in maxillofacial surgery.

Inclusion Criteria:

• American society of anesthesia (ASA) criteria I/II
• Scheduled for elective unilateral maxillo-facial surgery

Exclusion Criteria:

• Patients with polytrauma and fracture base of skull.
• Patients with known allergy to the study drugs.
• Patients with coagulopathy.
• Patients with infection at puncture site.
• Patients necessitating postoperative ventilation from the start, since it will be difficult to assess respiratory depression and postoperative pain.