Sleep apnea is temporary cessation of breathing for more than 10 seconds during sleep. Obstructive sleep apnea(OSA) is the most common cause of sleep apnea and is a very common disorder affecting 2-5% of the population worldwide. It can affect any age group ranging from children to old age but is more common in age groups between 40 to 60 years of age. Obstruction at the level of nose, oral cavity or upper digestive tract upto food pipe and dental and facial bony abnormalities can lead to airway obstruction. The airway is held open during the waking hours due to underlying tone of the muscles hence patient does not experience significant obstruction during daytime. But at night due to muscle relaxation in deep sleep and pull of gravity, the airway collapses and patient experiences episodes of fall in blood oxygen levels with cessation of breathing or apnea.

Polysomnography is the gold standard investigation to diagnose OSA. Polysomnography or commonly called as sleep study is a test used to diagnose sleep disorders. It assesses the periods of breathing cessation and periods of decreased oxygen flow to lungs and thus classifies whether patient has mild, moderate or severe OSA. The most common non invasive treatment modality for moderate to severe OSA is continuous positive airway pressure devices also known as CPAP.This device is worn as a splint or mask over nose and it delivers air at a positive pressure hence, it is able to overcome the obstruction in the airway. Patients who do not improve with lifestyle modifications, CPAP or mandibular devices may benefit from surgery to relieve the site of obstruction. To assess  the anatomic site of obstruction in OSA, drug induced sleep endoscopy(DISE) is done. DISE is an evaluation technique using fiberoptic endoscopy of nose and upper airway to examine the site of obstruction under sedation with sedative medications like propofol. It is designed to mimic the situation during natural sleep as closely as possible and hence ascertain what kind of surgery will benefit the patient for OSA.

1. a) NASAL SURGERY

Nasal surgery is usually done in patient with simple snoring who have impaired nasal breathing and may be done in addition to other surgeries for OSA in patients with obvious nasal pathologies. It has a lot of positive effects on sleep quality, recovery during sleep, and daytime symptoms in patients with nasal pathologies and also improves efficacy of CPAP.

1. Surgeries for the turbinates

Turbinates are bony structures in the nose covered with mucosa which help to humidfy the air inside the nose. Submucosal radiofrequency-induced thermotherapy (RFITT) is a treatment that can be used to improve nasal passage by using an electric probe to reduce the turbinate size.

More invasive surgery for the turbinates is called turbinoplasty in which the turbinates are trimmed to reduce them in size.

2. Surgery for the septum

Septum is the central bone in the nose which may be bent or deviated . This can cause nasal blockage in one or both nostrils. Septoplasty is a surgery which is done to correct this deviated bone.

3.Endoscopic Sinus Surgery

In patients with severe nasal obstruction with nasal polyps, patient may benefit with removal of the polyps  and widening the opening of sinuses with endoscope assisted sinus surgery.

B) MINIMALLY INVASIVE SURGERY

1. Interstitial Radiofrequency in the Soft Palate, tongue base and tonsils

In patients with simple snoring, radiofrequency waves may be used to shrink the size of tissues .This helps to tighten the tissues and reduce their volume and hence may reduce snoring. This can be done as a day care procedure and under local anaesthesia as well.

2. Palatal implants and Injection Snoreplasty

Injection with certain drugs can be given in the palate which causes a chemical reaction leading to fibrosis and tightening of the palate. This procedure is called injection snoreplasty. Palatal implant ( also called as the Pillar procedure) requires the insertion of three small fibrous polyester rods which cause fibrous reaction inside the tissue upon insertion. These procedures can give benefits in mild OSA and can be done in OPD as well under local anaesthesia.

C) UVULOPLATOPLASTY(UPP)

In patients with mild snoring at the level of uvula and soft palate only, uvulopalatoplasty with laser(laser-assisted uvulopharyngoplasty, or LAUP) or radiofrequency(Radiofrequency assisted uvulopharyngoplasty or RAUP) can be done to create wider space at the back of the throat by trimming the size of uvula and shortening the soft palate.

D) UVULOPALATOPHARYNGOPLASTY(UPPP)

This is one of the most common surgeries done in patients with OSA. The aim of this surgery is to increase the airway space behind the palate and reduce the collapse of the tissue behind the tongue by reducing the excess tissue over uvula and soft palate, shortening the soft palate with sutures to  keep it open and removal of tonsils if present. This surgery targets the area behind the tongue base which is called oropharynx. This is the most common site of obstruction in patients of sleep apnea  and hence a lot of patients show improvement with this procedure.

E)TONSILLECTOMY AND TONSILLOTOMY

Tonsillectomy is the complete removal of tonsils while tonsillotomy is partial removal of the tissue of tonsils. In children with OSA, tonsillectomy along with the removal of adenoids is done to improve the airway space. In adults, tonsillectomy is usually not done as the sole procedure and is usually done with UPPP or other procedures to improve overall space and hence the success of palatal procedures.

F) TONGUE SUSPENSIONS AND IMPLANTS

For patients with bulky tongue base causing visible obstruction and without typical findings at the soft palate, tongue base surgery maybe beneficial. In the tongue suspension systems, a non resorbable loop is passed through the tongue base and the loop is tightened to bring the tongue base forward.

G) LINGUAL TONSILLECTOMY

The lingual tonsils are lymphoid tissue that is located at the back of the tongue  base. They may be removed if sleep endoscopy shows them to be obstructing the breathing space. This surgery can be done with laser or coblator.

H) HYOID BONE SURGERIES

The hyoid bone is a U-shaped bone in the neck. The tongue and other structures of the throat are attached to it. Hyoid suspension involves pulling the hyoid bone forward and securing it in place with sutures to open up the lower airway space.

I) GENIOGLOSSAL ADVANCEMENT

Genioglossus is one of the muscles which holds the tongue in its place. In this surgery, a bony window is created in the front of jaw bone to reach to this muscle and the muscle with its attachment to the jaw bone is moved forward in comparison to rest of the jaw bone. This brings the tongue base forward and hence prevents the fall back during sleep.

J) HYPOGLOSSAL NERVE STIMULATION

Hypoglossal nerve innervates the muscles of tongue. In this surgery, a stimulating electrode device is attached to this nerve and programmed with external device to stimulate the nerve at night during sleep. This prevents the fall back of tongue and hence collapse of airway.

K) TONGUE BASE SURGERIES AND MIDLINE GLOSSECTOMY

These surgeries are done to reduce the volume of tongue base in patients with bulky tongue and hence improve the airway space.

L) TRACHEOSTOMY

Permanent tracheostomy is used in extreme life threatening situation in patients with OSA  when oxygen saturation is very low and patient is not able to breathe due to collapse of airway. This may be done as an elective procedure in patients who are not able to tolerate CPAP or are not suitable candidates for surgery or as an emergency procedure. In this procedure an opening is created in the windpipe from an incision in the neck below the level of voice box to bypass the upper airway which is usually the cause of obstruction in OSA. Individuals with a tracheostomy for OSA plug the opening during the day, allowing them to speak normally, but remove the plug for sleep.

M) MAXILLOMANDIBULAR ADVANCEMENT SURGERY

This surgery is beneficial to patients who have abnormalities of the maxillofacial skeleton. A small, narrow jaw can result in narrow airway space which can lead to obstruction during sleep. Maxillomandibular advancement involves the fracture of both upper and lower jaw bones and advancing them forward. These are then fixed with plates and screws and hence this leads to expansion of space in  the upper airway. The procedure is dificult and requires expertise but may have good results in carefully selected patients.

N) PARTIAL EPIGLOTTIDECTOMY AND EPIGLOTTOPEXY

Epiglottis is a tongue shaped structure which protects the opening of voice box. If the sleep endoscopy shows collapse of this structure during breathing then partial removal of epiglottis can be done to increase airway space. This procedure is usually performed with laser.

O) BARIATRIC SURGERY

This is often used as the last resort in patients with severe OSA who do not improve with any of the above treatment options. Many types of surgeries are done with the most common being gastric bypass.

CONCLUSION

The surgery for Obstructive sleep apnea (OSA) needs to be assessed for each patient separately and there is no one answer that fits all. In addition to detailed history, clinical examination and radiological investigations, drug induced sleep endoscopy (DISE) remains an important guide to the surgeon to assess the exact site of snoring and airway collapse and hence decide the surgery required. UPPP remains the most common surgery performed for OSA although other surgeries may be done in conjugation with UPPP as well or separately depending upon site of obstruction.