HYPOGLOSSAL NERVE STIMULATION AND ITS ROLE IN SLEEP APNOEA
Updated: Jul 17
Tongue and tongue base collapse is one of the predominant causes of sleep apnoea. However, it is not the only cause. Sidewall collapse, soft palate collapse and tonsil collapse are other sites of obstruction. In order to benefit, all the sites of collapse must be addressed by surgery.
Hypoglossal nerve stimulation functions by activating the nerve that supplies muscles of tongue. It works by forward contraction of the tongue and other muscles by electrical stimulus, when switched on. The electrodes are placed on the Hypoglossal Nerve, and the external part is implanted in the chest, and switched on at night to keep the upper airway open during sleep. In a way, it could be considered surgical positioning of an appliance rather than surgical correction of the airway. It acts similar to a pacemaker for the heart.
A meta-analysis (compiling data of many studies) was done and published in the World Journal of Otolaryngology and Head and Neck Surgery in 2019*. Sixteen papers were identified for this systematic review, and 381 patient results were analysed. Data showed that at six months, there was 40% reduction of sleepiness (mean score was reduced by 5) and 62% reduction of AHI-apnoea events (mean AHI was reduced by 21). These results remained stable at 12 months as long as device was used. The benefit did not last long if device was discontinued
However, there were strict guidelines for selection. They had to fail other methods of management and also have a BMI of less than 35. They could not have severe collapse (circumferential collapse) of the soft palate. They had to have less than 50 AHI (Apnoea events) per hour. In summary, they had to have a certain type of anatomy to benefit from hypoglossal nerve stimulation.
Overall the risks were low. Some of the risks included intolerance to use of the machine, pain, device malfunction, migration of the device, but no major complications were noted. Conclusion was that nerve stimulation may not be the definitive choice for for second line therapy but it is a useful tool in managing OSA.
At CSSC Mornington we perform a technique called “MODIFIED BRP AND TONGUE CHANNELLING’’. The technique has evolved from putting together the best aspects of a European technique and an Australian technique. Our prospective and retrospective data has shown mean reduction of sleepiness score by 65% (from 12.2 to 4.4). CSSC Mornington has shown 80% surgical success in Freedman III (most difficult anatomy). Overall reduction of Apnoea Events (AHI) was over 60%. Over 90 % of the operated patients avoided CPAP due to combination of weight-loss, slide sleeping, or infrequently by use of a mouthguard. We have presented our preliminary data at AOHNS 2019, 2020.
Properly performed soft tissue surgery will remain the best second line therapy, for those not willing CPAP. Our impression is that nerve stimulation will continue play a beneficial role in a very select group of patients.
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*World Journal of Otorhinolaryngology - Head and Neck Surgery: Volume 5, Issue 1, March 2019, Pages 41-48