Overview of phase II surgery for obstructive sleep apnea syndrome.Introduction
Obstructive sleep apnea Obstructive sleep apnea (OSA)
A potentially life-threatening condition characterized by episodes of breathing cessation during sleep alternating with snoring or disordered breathing. syndrome (OSAS OSAS Obstructive Sleep Apnea Syndrome
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OSAS Ohio Scottish Arts School ) can result in daytime fatigue and sleepiness that significantly affects, and even threatens, the life of the patient. Tracheotomy tracheotomy (trākēŏt`əmē), surgical incision into the trachea, or windpipe. The operation is performed when the windpipe has become blocked, e.g., by the presence of some foreign object or by swelling of the larynx. was the first treatment for OSAS. It bypasses all forms of obstruction in the upper airway, thus eliminating the disease. However, the morbidity associated with tracheotomy prevents its use in most patients.
Sullivan et al first reported the application of nasal continuous positive airway pressure continuous positive airway pressure
Abbr. CPAP A technique of respiratory therapy for individuals breathing with or without mechanical assistance in which airway pressure is maintained above atmospheric pressure throughout the (CPAP CPAP
continuous positive airway pressure
Continuous positive airway pressure (CPAP)
A ventilation device that blows a gentle stream of air into the nose during sleep to keep the airway open. ) to maintain upper airway patency pa·ten·cy
The state or quality of being open, expanded, or unblocked.
the condition of being open. for OSAS.  Because of its effectiveness, nasal CPAP is currently the first-line treatment for OSAS. However, patient compliance remains a major problem, and the long-term use of CPAP is likely to be an unrealistic expectation in many cases. [2-4]
In 1979, Fujita et al reported the initial results of uvulopalatopharyngoplasty in the treatment of OSAS.  Although the procedure has proved to be an excellent method of alleviating palatal pal·a·tal
palatal (pal´t (pharyngeal pharyngeal /pha·ryn·ge·al/ (fah-rin´je-al) pertaining to the pharynx.
pha·ryn·geal or pha·ryn·gal
Of, relating to, located in, or coming from the pharynx. ) airway obstruction, the untreated base-of-tongue (hypopharyngeal) obstruction resulted in only approximately 40% of patients responding to treatment. 
Recognizing that multiple levels of upper airway obstruction exist in OSAS, we developed several procedures to target the specific anatomic regions involved. Our two-phase surgical protocol was designed to alleviate the anatomic obstruction(s) while minimizing surgical interventions and avoiding unnecessary surgery. The phase I surgical protocol addresses obstructions at the nasal, palatal, and base-of-tongue levels. Phase I procedures include nasal reconstruction, uvulopalatopharyngoplasty, mandibular mandibular
adj pertaining to the lower jaw. osteotomy osteotomy /os·te·ot·o·my/ (os?te-ot´ah-me) incision or transection of a bone.
cuneiform osteotomy removal of a wedge of bone. with genioglossus advancement, and hyoid hyoid /hy·oid/ (hi´oid) shaped like Greek letter upsilon (?); pertaining to the hyoid bone.
1. Shaped like the letter U.
2. Of or relating to the hyoid bone. myotomy and suspension. In 1992, we reported a cure rate of 61% following phase I surgery.  Depending on the severity of OSAS, the success rate of phase I surgery ranges from 42 to 78%.  Clearly, many patients continue to experience persistent disease following phase I surgery, and most of them become candidates for phase II surgery. Phase II surgery consists of maxillomandibular advancement, a procedure that was first described for the treatment of craniomaxillofacial deformity.
Rationale for maxillomandibular advancement
The contributing causes that lead to OSAS are multifactorial multifactorial /mul·ti·fac·to·ri·al/ (mul?te-fak-tor´e-al)
1. of or pertaining to, or arising through the action of many factors.
2. , and they can have a negative influence on the delicate balance necessary for airway patency during sleep. In addition to obesity, male gender, age, and ethnicity, [8-10] craniomaxillofacial abnormality is a well-recognized predictor of OSAS. [11-13] Many of these patients have a maxillomandibular deficiency that results in a diminished airway dimension and leads to nocturnal obstruction. In 1983, we reported that maxillofacial surgery via mandibular advancement can play a role in the treatment of OSAS.  Mandibular movement forward will help in alleviating a hypopharyngeal obstruction. This finding has also been recognized by others. [15-17] In fact, it was reported that mandibular setback for the correction of mandibular prognathism prognathism /prog·na·thism/ (prog´nah-thizm) abnormal protrusion of the mandible.prognath´icprog´nathous
prognathism (prog´n has produced OSAS.  We subsequently investigated the effect of maxillomandibular advancement on the airway and have included this procedure as the second phase of our surgical protocol. 
Maxillomandibular advancement enlarges the pharyngeal and hypopharyngeal airway dimensions by physically expanding the skeletal framework. In addition, the forward movement of the maxillomandibular complex improves the tension and collapsibility of the suprahyoid and velopharyngeal musculature. The indications for maxillomandibular advancement are outlined in table 1.
Most patients who undergo phase II surgery have failed to fully respond to the phase I protocol. These patients have already undergone reconstruction of the airways at the nasal, pharyngeal, and hypopharyngeal levels. Phase I surgical failure almost always involves persistent obstruction at the hypopharyngeal level (occasionally combined with pharyngeal-level obstruction). Maxillomandibular advancement creates more tension and physical room in the upper airway, relieving residual obstructions. In order to maximize airway expansion, a major advancement of the maxillomandibular complex is required. However, in doing so, it is important to maintain a stable denial occlusion and a balanced aesthetic appearance. Many patients who enter the phase II protocol have craniomaxillofacial abnormalities, such as maxillary max·il·lar·y
Of or relating to a jaw or jawbone, especially the upper one.
A maxillar; a jawbone.
adj and/ or mandibular deficiencies, that invariably are improved following surgery. We have often found that even patients whose cephalometric measurements are normal also experience an improvement in their facial appearance following maxillomandibular advancement. This is because many of our patients are middle-aged adults who are already showing signs of facial aging as a result of soft tissue sagging. The skeletal expansion of the maxilla maxilla /max·il·la/ (mak-sil´ah) pl. maxil´las, maxil´lae [L.] the irregularly shaped bone that with its fellow forms the upper jaw. max´illary
n. pl. and mandible enhances their appearance by improving soft tissue support. This positive influence on aesthetics has been reported by others. [20-22]
Maxillomandibular advancement has been performed for many years to correct malocclusion Malocclusion Definition
Malocclusion is a problem in the way the upper and lower teeth fit together in biting or chewing. The word malocclusion literally means "bad bite. in children and young adults, and it is well described in the maxillofacial surgery literature. However, it must be emphasized that the procedure for the treatment of OSAS is quite different from the conventional orthognathic procedure.
The procedure begins with an outer-table cranial bone harvest. Bone grafts are placed at the osteotomy sites to facilitate bony union. To maintain dental occlusion, either arch bars or orthodontic orthodontic (ôr´thdän´tik),
adj bands are required prior to osteotomy. A Le Fort I maxillary osteotomy (figure) is performed above the apices a·pi·ces
A plural of apex. of the teeth. The maxilla is down-fractured after pterygomaxillary separation. The descending palatine arteries are identified and preserved. The mobilized maxilla is manipulated and advanced approximately 10 mm. Alignment of the maxilla in relation to the mandible, dentition dentition, kind, number, and arrangement of the teeth of humans and other animals. During the course of evolution, teeth were derived from bony body scales similar to the placoid scales on the skin of modern sharks. , and the face is crucial to ensure acceptable occlusion and aesthetics. The maxilla is stabilized by rigid fixation with four plates, and the cranial bone grafts are used in the osteotomy sites.
Mandibular osteotomy is performed via the sagittal sagittal /sag·it·tal/ (saj´i-t'l)
1. shaped like an arrow.
2. situated in the direction of the sagittal suture; said of an anteroposterior plane or section parallel to the median plane of the body. split technique. The medial and lateral cortex of the mandible are separated at the ramus ramus /ra·mus/ (ra´mus) pl. ra´mi [L.] a branch, as of a nerve, vein, or artery.
ramus articula´ris region, while the inferior alveolar nerve inferior alveolar nerve
A terminal branch of the mandibular nerve that is distributed to the lower teeth, periosteum, and gums of the mandible. is preserved. The dentated mandibular segment is advanced the same distance as the maxilla, and occlusion is restored. After the mandible is stabilized by intermaxillary fixation, rigid fixation is achieved with the placement of four positional screws (plates are also occasionally used to ensure rigidity).
We routinely use a prefabricated pre·fab·ri·cate
tr.v. pre·fab·ri·cat·ed, pre·fab·ri·cat·ing, pre·fab·ri·cates
1. To manufacture (a building or section of a building, for example) in advance, especially in standard sections that can be easily shipped and methylmethacrylate splint splint, rigid or semiflexible device for the immobilization of displaced or fractured parts of the body. Most commonly employed for fractures of bones, a splint may be a first-aid measure that allows the patient to be moved without displacing the injured part, or it to ensure dental alignment. Skeletal fixation with suspension wires is sometimes used to enhance the stabilization of the maxillomandibular complex.
Perioperative perioperative /peri·op·er·a·tive/ (-op´er-ah-tiv) pertaining to the period extending from the time of hospitalization for surgery to the time of discharge.
As always, anesthesia induction and intubation intubation /in·tu·ba·tion/ (in?too-ba´shun) the insertion of a tube into a body canal or hollow organ, as into the trachea.
endotracheal intubation are especially critical for OSAS patients, and the surgeons should be present at all times. A fiberoptic intubation or tracheotomy while the patient is awake should be considered in difficult airway situations, especially in obese patients who have a large neck circumference ([greater than]46 cm) and associated skeletal deformities (e.g., mandibular deficiency and a low hyoid bone hyoid bone
A U-shaped bone at the base of the tongue that supports the muscles of the tongue.
hyoid bone (hī´oid),
n ). Although blood transfusion is often unnecessary, we prefer to have two units of autologous autologous /au·tol·o·gous/ (aw-tol´ah-gus) related to self; belonging to the same organism.
1. blood available.
All patients are extubated while they are awake, and intermaxillary fixation is in place in the operating room immediately following surgery. Wire cutters are kept near these patients at all times. All patients are monitored via an arterial line in the intensive care unit during the first postoperative day. Either humidified oxygen (35%) through a face tent or nasal CPAP is administered throughout hospitalization. Patients who receive CPAP require nasal trumpets to prevent subcutaneous emphysema. Patients are transferred to the ward the following day. Discharge criteria include a stable airway, adequate oral intake of fluids, and satisfactory pain control. Intermaxillary fixation is left in place for several days.
Surgical protocol clinical outcomes
Of the 175 patients who underwent phase II reconstruction at our institution between 1988 and 1995, 166 (95%) had a successful outcome (table 2). Their mean respiratory disturbance index The respiratory disturbance index is similar to the apnea-hypopnea index, however, it also includes respiratory events that do not technically meet the definitions of apneas or hypopneas, but do disrupt sleep. See also
1. the act or process of adding oxygen.
2. the result of having oxygen added. saturation (LSAT LSAT
Law School Admissions Test
LSAT (US) n abbr (= Law School Admissions Test) → Zulassungsprüfung für juristische Hochschulen ) level improved from 64 to 86.7% (nasal CPAP LSAT: 87.5%; p=NS). Eighty-six of these patients had failed our phase I surgical protocol, and 83 of them (97%) were cured with phase II surgery. Most of the patients who failed the phase I protocol and declined phase II surgery were older (mean age: 51.8 yr). The mean age of patients who underwent phase II treatment was 43.5 years.
The mean length of hospital stay after phase II surgery was 2.4 days. Surgical morbidity included transient anesthesia of the lower lip, chin, and cheek in all patients; 87% of these cases resolved in 6 to 12 months. There was no postoperative bleeding or infection. Mild malocclusions were seen in some patients, and they were treated adequately with occlusal occlusal /oc·clu·sal/ (o-kloo´z'l)
1. pertaining to the masticating surfaces of the premolar and molar teeth.
1. adjustment. No major skeletal relapse has been reported.
To date, we have performed long-term followup on more than 50 patients who underwent phase II surgery. Thirty-three of these patients have undergone followup polysomnography (table 3). Eighteen patients who fused polysomnography are monitored through interviews that concern the subjective symptoms of OSAS. Four patients have been lost to followup.
Of the 33 patients who underwent followup polysomnography, 30 have experienced long-term surgical success; the other three patients had initial success, only to relapse to OSAS. Overall, the mean RDI in this group fell from 69.6 preoperatively to 8.9 at 6 months postoperatively and to 7.7 at long-term followup. Similar improvement over baseline was seen in 6-month and long-term LSAT values. Followup ranged from 12 to 110 months (mean: 39).
Of the 18 patients who were subjectively reviewed by the lead author, 16 continued to experience good subjective correction. They had no progressive snoring, no apnea and no excessive daytime sleepiness excessive daytime sleepiness Sleep disorders A subjective difficulty in maintaining an awake state, and an increase ease of falling asleep when the person is sedentary; EDS may be quantified with subjective rating scales of sleepiness . Of the two patients who did not improve, one experienced a subjective failure (recurrence of snoring and daytime fatigue) and the other had both a subjective and objective failure (his primary care physician had referred him for a polysomnogram, which showed a recurrence of OSAS).
From the Center for Excellence in Sleep Disorders Medicine, Stanford (Calif.) University School of Medicine.
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Maxillomandibular advancement is an extremely effective surgical procedure for the treatment of obstructive sleep apnea syndrome. When properly executed, it is associated with minimal morbidity and is well accepted by patients. It is a treatment option that achieves long-term cure.
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Phase II surgical outcomes Successful Total no. Success Surgery groups outcomes patients rate Failed phase I 83 86 97% Skeletal deformity 10 11 91% (without UPPP [*]) Failed UPPP [+] 73 78 94% Total 166 175 95% (*.)Uvulopalatopharyngoplasty. (+.)Outside referral for severe obstructive sleep apnea syndrome. Long-term polysomnographic followup Surgery groups RDI [*] LSAT [+] Pre-op 69.6 [plus or minus] 27.9 68.5 [plus or minus] 14.3 Post-op 8.9 [plus or minus] 5.5 85.4 [plus or minus] 4.6 Long-term 7.7 [plus or minus] 5.3 86.4 [plus or minus] 3.7 followup Surgery groups Months Pre-op -- Post-op 6 Long-term 39 [plus or minus] 24 [++] followup (*.)Respiratory disturbance index. (+.)Lowest oxygenation saturation. (++.)Range: 12 to 110 months.
Criteria for maxillomandibular advancement
Severe obstructive sleep apnea syndrome
Morbid obesity (body mass index: [greater than]33 kg/[m.sup.2])
Satisfactory desire and health to undergo and recover from surgery
Failure of other forms of treatment, both medical and surgical3