Hypnotising the patient during a surgery for a brain cancer has been found effective to help reduce pain and avoid psychological trauma. A new study suggests a "hypnosedation" technique could allow a patient undergoing awake brain surgery for the brain cancer glioma avoid feeling the pain and stress during the operation.

The study, published in the journal Neurosurgery, shows that hypnosis has a high rate of success on its initial evaluation in patients undergoing awake craniotomy for the disease. Researchers believe the technique could significantly help patients with more advanced brain cancers.

Hypnosis delivers sedation and relaxation during the brain surgery. For the study, an anesthesiologist or hypnotist meets the patient few weeks before the surgery for a short hypnosis session and to teach the patient how to make a "safe place," or an imaginary place where they feel safe and effective.

The researchers analysed the effect of the hypnosis technique in 37 patients undergoing awake craniotomy, most with low-grade gliomas, between 2011 and 2015. In awake craniotomy, surgeons sedate the patients and require them to stay conscious to be able to communicate during the operation.

With the patients being awake during the process, the surgeon could work on the tumour safely without damaging the eloquent cortex, the areas of the brain involved in language or movement.

For the hypnosedation during the brain surgery, patients were instructed to "let go" and to "separate the mind and body." The hypnotist progressively enhances their hypnotic experience during the first steps of surgery, providing instructions and imagery to the patient for each potentially unpleasant or painful step of the operation.

Unfortunately, hypnosis failed in six of the 37 patients as they underwent standard asleep-awake-asleep anaesthesia. However, the technique successfully reduced the impact of unpleasant events during surgery in other patients.

One patient, who showed signs of post traumatic stress disorder after surgery, reported a good experience with hypnosis. In most patients, the most unpleasant parts of surgery were steps that involve noise and vibration, but the pain has been found to decrease as the level of hypnosis deepened during the process.

The researchers believe the effect of hypnosis could be strongly related to the patients' motivation and determination. Hypnosedation allows the patients to remain awake throughout the surgery, helping them avoid the standard asleep-awake-asleep anaesthesia, which could be challenging in patients with high-grade gliomas.

However, the researchers noted the initial evaluation provides no evidence that hypnosedation works better than standard anaesthesia. The technique requires more time and commitment to prepare the team and the patient.