Effects of Local Ketamine in Orthognathic Procedures

Orthognathic surgery is performed to correct congenital or developmental anomalies of the maxilla and mandible, as well as secondary deformities caused by trauma. These procedures require multiple incisions, dissections, and osteotomies in both the maxilla and mandible. The acute postoperative pain that follows orthognathic surgery is primarily the result of these surgical traumas and the subsequent inflammatory process. As tissue healing progresses, postoperative pain gradually subsides. This type of pain is one of the primary factors affecting postoperative recovery, return to function, and length of hospital stay.

Many studies have focused on achieving optimal analgesia during this period, which significantly affects patients' postoperative quality of life. For this purpose, several agents have been used, including non-steroidal anti-inflammatory drugs (NSAIDs), opioids, non-opioid analgesics (such as acetaminophen), NMDA receptor antagonists, and long-acting local anesthetics.

Ketamine is a well-known general anesthetic and short-acting intraoperative analgesic agent with established pharmacodynamic and pharmacokinetic profiles and known side effects. Ketamine is a non-selective antagonist of supraspinal N-methyl-D-aspartate (NMDA) receptors. It is believed that inhibition of these receptors reduces neuronal excitation and produces analgesia through this mechanism. Ketamine's interactions with spinal pain receptors and opioid receptors are also thought to contribute to its analgesic effects.

In low doses, ketamine has been evaluated for local analgesic purposes in combination with local anesthetics in various surgical procedures, aiming to minimize side effects. Cleft palate repair and third molar extractions are among the oral surgery procedures where the local analgesic efficacy of ketamine has been investigated. In a study by Jha et al. on cleft palate repair, the authors examined the effects of local bupivacaine combined with ketamine on postoperative nausea, vomiting, dysphagia, and sleep patterns. They found that patients in the ketamine group had superior outcomes in terms of reduced need for additional analgesia, improved sleep, and earlier return to feeding.

Similarly, in the literature some studies reported that significant reductions in postoperative pain, swelling, and trismus in third molar extraction patients when sub-anesthetic doses of ketamine were combined with local anesthetics. Shah et al. also observed that combining ketamine with local anesthetics during third molar extraction reduced postoperative pain and swelling compared to local anesthetics alone.

To date, there are no studies in the literature investigating the effects of combining ketamine with local anesthetics in orthognathic surgery. Therefore, this study was designed to address this gap.

Inclusion criteria

• Patients with Class II or Class III skeletal deformities who underwent bimaxillary orthognathic surgery due to dentofacial deformities.
• ASA I-II physical status patients.
• Patients aged between 18 and 45 years.
• Patients who received anesthesia induction and maintenance with propofol (0.2-0.6 mg/kg/hour) titrated to maintain an entropy score between 40-60, and remifentanil (0.05-0.5 mg/kg/hour) adjusted to maintain a Surgical Pleth Index (SPI) between 20-50.
• Patients who received a combination of local anesthetic and ketamine.
• Patients who were administered patient-controlled analgesia (PCA) at the end of the surgery and whose opioid consumption via PCA was monitored during the first 24 hours postoperatively.
• Patients whose nausea-vomiting scores and need for antiemetics were recorded.
• Patients with complete documentation of anesthesia records, including entropy scores, SPI values, and total doses of propofol and remifentanil administered.
• Patients with completed postoperative edema follow-up forms.

Exclusion criteria

• Patients with a known allergy to ketamine.
• Patients with uncontrolled systemic diseases.
• Patients using psychotropic medications.
• Patients with a history of substance abuse.
• Patients with chronic pain lasting longer than 3 months.
• Patients using analgesic or hypnotic medications for more than 2 weeks.
• Cases in which complications occurred during surgery that required deviation from the standard orthognathic surgical protocol and could potentially affect postoperative pain levels (e.g., bad split, unexpectedly prolonged surgical duration, etc.).