Eur Respir J 1989, 2. 604--<;12

Maxilla-mandibular surgery for obstructive sleep apnoea

C. Guilleminault*, M.A. Quera-Salva*, N.B. Powell**, R.W. Riley**

Maxillo-mMdibular surgery for obstructive sleep apnoea. C. Cuillemin.ault, M.A. Quera-Salva. N.B. Powe/1, R.W. Riley.

Stanford University School of Medicine* and Head-Neck Surgery**, Palo Alto, California, USA.

ABST RACT: Many therapeutic approaches, including mandibular sur­gery, bave been proposed for the treatment of obs tructive s leep apnoea syndrome. In the large.c;t study of Its type yet reported, 54 patients (popu· latlon A) underwent mandibular surgery: 36 had palato-pharyngoplasty and Inferior sagittal osteotomy of the mandible with hyoid myotomy and resuspenslon, and 18 (population B) had ma:d llo-mandlbular hyoid ad­vancement, a procedure consisting of palato-pharyngoplasty, inferior sagittal osteotomy of the mandible with hyoid myotomy and, sever al months later, a maxlllo-mandibular osteotomy. Criteria for procedure selection and for evaluation of results were pre-set, and cllnlcal and poly­graphic follow-up occurred ~ months after final surgery. In popula­tion A, 32 of the 36 patients had Improved; but only 20 were evaluated as "satisfactory". I n contTast, all of the population D patients were judged satis fa ctory. Four of t11e popu lation 13 pa tients received nasal continuous positive ainvay pressure (CPAP) before any surgery, and botb approaches gave similar good polygraphic resulto;, The degree of skeletal cranio­facial deficiencies, particularly retrognathJa, Is crucial for procedure selection. We describe potential procedural r isks and problems.

Correspondence: C. Guilleminault, Sleep Disorders Center, 701 Welch Road, Suite 2226, PaJo Alto, CA 94304, USA.

Keywords: Mandibular osteotomy; maxillary osteotomy; obstructive sleep apnoea; palato­pharyngoplasty.

Received: March, 1988; accepted after revision March 19, 1989.

This worlc was supported by grant AG 06066 from the National Institute of Aging.

Eur Respir J., 1989, 2, 604~12.

Surgical approaches were the first means of control­ling the disabling symptoms of obstructive sleep apnoea syndrome (OSAS). KULHO et al. (I] are credited with performing the first tracheostomy to bypass an obstruc­tion that occurred during sleep in the upper airway of a very obese patient. FumA et al. [2) initiated uvulopalato-pharyngoplasty (UPPP) in OSAS patients sent for tracheostomy, and nocturnal polygraphic record­ings indicated successfuJ long-term results in 45% of these patients [3-5].

Studies of fail.ures of UPPP have led to beuer prc­surgical evaluation of the sublle, and often multiple, anatomical upper airway abnormalities presented by OSAS patients. JAMlESON et al. [6], after reviewing 155 consecutive cases, concluded that 150 had at least two markedly abnormal anatomical cranio-facial landmarks. Their patients commonly had a normally positioned maxilla; a retroposition of the mandible, a steep mandi­bular plane, a cranial base flexure with a nasion-sella-basion angle smaller than expected, a down­ward displacement of the hyoid bone, and a significant increase in the length of the soft palate. RoJEwsKI et al. [7], using video-endoscopy, noted the "disproportionate anatomy" of patients with OSAS; and RIVLIN et al. [8] emphasized the overall displacement of the mandibular symphysis. These displacements easily explain the known abnormalities of the soft tissue of the upper air­way; the different levels of obstruction during sleep explain the frequent failures in the treatment of OSAS

by UPPP, which eliminated only one site of obstruc­tion.

SutLNAN et al. [9] proposed nasal continuous posi­tive airway pressure (CPAP) during sleep as a home treatment for OSAS. While nasal CPAP is successful in controlling the symptoms of many OSAS patiems, follow-up studies have indicated problems with compli­ance [10]. Between 25 and 30% of patients arc non­compliant for reasons that include nocturnal rhinitis and the inconvenience of being attached to a machine ev­ery night for many years. These difficulties have led us to investigate new surgical procedures that would cor­rect the abnonnal upper airway noted in OSAS.

Surgical procedures

Two maxillo-mandibular procedures have been devel­oped and previously reported by RILEY and eo-workers [11- 13].

Inferior sagittal osteotomy with hyoid myotomy and suspension

This procedure [11] consists of: 1) a limited osteot­omy involving the genio-tubercle, Lhe anterior point of insertion of the tongue muscles; 2) a section through a submental incision of stemo-, stylo- and omo-hyoid muscles; and 3) the suspension of the hyoid bone to

OBSTRUCTIVE SLEEP APNOEA AND MANDIBULAR SURGERY 605

the mandible, anteriorly and superiorly with fascia. The procedure is performed with UPPP, and if necessary, tonsillectomy (figs la and lb).

Figs. la and lb. - Schematic representation of inferior sagittal os­teotomy with hyoid myotomy and suspension. The region involving the genio·tubcrcle is cut and positioned anteriorly. The sternohyoid, stylohyoid, and omo-hyoid muscles are sectioned and the hyoid bone is resuspended to the mandible anteriorly and superiorly with fascia (fig. la).

Maxillo-mandibular and hyoid advancement

This procedure [12] is planned in two steps, usually separated by a 3-4 month interval. Step 1 consists of a combined UPPP and inferior sagittal osteotomy of the mandible. Following orthodontic preparation during the interval, step 2 consists of a maxillo-mandibular osteot­omy (i.e. Lefort-one osteotomy and sagittal split mandi­bular osteotomy), with liposuction of the neck, if

Fig. 2. - Schematic representation of maxilla-mandibular and hyoid advancement. The first step is described in figures la and lb. Phase 2 consists of a combined maxilla- and mandibular-osteotomy which allows advancement of the mandible with good conservation of the bite.

indicated (fig. 2). Step 2 was initially performed under the protection of a transient tracheostomy kept in place for 3-4 wks, but the last 25 patients submitted to this procedure have received nasal CPAP immediately post­extubation, thus eliminating the need for tracheostomy [13].

Pre-established criteria for surgical selection

The gross indications for each of these surgical ap­proaches had been determined by prior evaluation of several small OSAS patient groups. The degree of skeletal cranio-facial deficiencies, particularly retrognathia, must be moderate for successful results with inferior sagittal osteotomy of the mandible with hyoid myotomy. Candidates for inferior sliding osteot­omy should have an SNB angle (i.e., angle measure­ment from sella (S) to nasion (N) to supramentale (point B) at cephalometric X-ray) >75° and no morbid obesity. These limitations do not apply to maxillo­mandibular hyoid advancement. The usual contra-indications to non-emergency surgery related to significant medical and psychiatric problems are, of course, observed.

Patient population

All 54 patients treated consecutively during a 9 month period, and returning for follow-up, are presented here. Two patients undergoing inferior sagittal osteot­omy of the mandible refused to return for the follow­up and could not be included.

Clinical symptoms of OSAS were presented in all patients, who were apprised of the therapeutic options

606 C. GUILLEMINAULT ET AL.

currently available and the known risks and problems associated with the surgical approaches. The patients presented here had either refused any other treatment or had first tried nasal CPAP (see below) in anticipa­tion of another treatment approach. All obese patients had previously been in weight-loss programmes; one patient had previously lost 99 kg, but had returned to 185 kg at the time of consultation. Following the pre­established criteria outlined above, the patient popula­tion was divided into subgroups A and B, based on the degree of: 1) retroposition of the mandible (indicated by the SNB angle); and/or 2) obesity and fatty infiltra­tion of the neck; and 3) severity of the syndrome as revealed by the respiratory disturbance index (RDI) and apnoea-linked oxygen desaturation. Patients with one or more "severity" factors, i.e. clear retrognathia, marked obesity, and/or many abnormal polygraphic results, were considered from the start to be candidates for the two­step maxilla-mandibular-hyoid advancement (population B, n=l8). All other patients (population A, n=36) were considered as candidates for inferior sagittal osteotomy with hyoid myotomy and suspension, a less extensive surgery not involving orthodontic preparation. UPPP, as mentioned previously, was always performed.

Ten of the 54 patients considering mandibular surgery (8 in group A and 2 in group B) had already under­gone an unsuccessful UPPP elsewhere. Imaging techniques and fibreoptic endoscopy indicated the per­sistence of a narrow airway behind the base of the tongue. The presurgical recording reported for these patients was the one performed post-UPPP but pre­mandibular surgery.

Patient population A (inferior sagittal osteotomy with hyoid myotomy and suspension) consisted of 36 male patients, mean age 4 7 .5± 11.8 yrs; and mean body mass index (BMI) 30.9±5.7 (range 19.2-44), indicating a mixture of slender and obese subjects.

Patient population B (maxillo-mandibular hyoid ad­vancement) consisted of 18 patients, 16 men and 2 women, mean age 41±13.5 yrs (range 18-63 yrs), and mean BMI 31±7.4 (range 19-41.5), again indicating a mixture of body types. The mean BMI for both groups, however, pointed to a generally overweight population.

Methods

Each subject had: 1) nocturnal polygraphic recording pre- and 6 months post-surgery; 2) evaluation of sub­jective symptoms pre- and post-surgery; 3) pre-surgical cephalometric roentgenograms and evaluation by fibre­optic endoscope; and 4) evaluation of complications during and after surgery. Four patients in population B were also treated with nasal CPAP before any surgery. Polygraphic recordings obtained during sleep allowed comparison between nasal CPAP recordings and post­surgical recordings.

To confirm validity of pre-established criteria and to forestall unnecessary surgery. all patients in population B had a new polygraphic recording a mean of 2 months post step 1 surgery. Although these results are given for

completeness of presentation, the overall study com­pared subjects 6 months after surgery.

Polygraphic recordings and definition of breathing abnormalities

Electroencephalogram, electro-oculogram, chin elec­tromyogram, and electrocardiogram (modified V2 lead) were systematically recorded. Respiration was monitored by uncalibrated inductive respiratory plethysmography; airflow was monitored by thermistors, and arterial oxy­gen saturation (Sao2) by ear oximetry (Biox). Apnoea, hypopnoea and sleep stages were scored according to standard definitions based upon findings obtained from respiratory, airflow, oximetric and other channels. Hy­popnoea was defined as; a) a 50% reduction in maxi­mal thermistor output compared with baseline output; and b) association with a decrease of Sao

2 to <92%

from baseline of at least 94%, or a drop in Sao2

of at least 3% if baseline was <90%. The RDI or (apnoea + hypopnoea) x 60/total sleep time (TST), which takes into account the number of abnormal breathing events per hour of sleep, was calculated.

Definition of Sao2

indices

Several indices of Sao2 were calculated. Mean noc­turnal Sao2 was calculated using the formula of BRADLEY et al .(14]: the highest and lowest Sao

2 of each

polygraphicaUy recorded "epoch" were measured. Be­cause the pattern of desaturation and resaturation in OSA approximates a sine wave, the mean Sao2 of each polygraphic epoch, i.e. 30 s, was estimated by averag­ing the high and low values. Mean nocturnal Sao2 for TST was then calculated using the mean values of all epochs.

To further focus on events leading to significant oxy­gen desaturation, even if short-lived, we calculated the number of Sao2 drops related to apnoea and hypopnoea ~80% and, as with the RDI, calculated the number of Sao2 drops per hour of sleep (02-80-I). The time spent at an Sao2 below 90% (T <90%SaoJ during nocturnal sleep is self-explanatory.

Indices of sleep disturbance

Using the criteria of REcHTSCHAFFEN and KALES [15), sleep was scored in 30 s epochs. We performed statis­tical analyses on the percentage of Stages 1 and 3-4 non-rapid eye movement (NREM) and rapid eye move­ment (REM) sleep during TST.

Cephalometric roentgenograms

Lateral cephalometric roentgenograms were obtained with the Wehmer cephalostat, using the technique of R!LEY et al. [16). Tracings of the roentgenograms were

OBSTRUCTIVE SLEEP APNOEA AND MANDIBULAR SURGERY 607

made on an acetate sheet and specific angles in degrees, or dimensions in mm, were selected for further analy­sis (fig. 3). This information was supplemented by a visual inspection of the region by fibreoptic endoscopy performed on a supine patient.

The BMI was calculated by the method of KHosLA and LowE [17] (weight [in kg] x 10,000/heightl [in cm)).

Fig. 3. - Normative values obtained on cephalometric X-rays. SNA: angle measurement from sella (S) to nasion (N) to subspinale (A); SNB: angle measurement from sella (S) to nasion (N) to supramen­tale (B); SNA and SNB (in degrees) describe the maxillary and mandibular position in relation to the cranial base; MP-H: distance from mandibular plane to hyoid bone (in mm); PNS-P: posterior nasal spine to tip of soft palate (P) indicates length (in mm) of soft palate; pas: posterior airway space (in mm), defined as the space be­hind the base of the tongue. SNA angle=82±2°; SNB angle= 80±2°; GoGn-SN angle=36±6°; NSBa angle= l37±5.7°; MP-H dis­tance=l5.4±3 mm; PNS-P distance=37±3 mm; pas distancc::ll± l mm.

Statistical analysis

Pearson coefficient correlation indicated degrees of correlation between variables. A Bartlett test for homo­genity of variance was calculated and, depending on results (p<0.05), a matched paired t-test or Wilcoxon signed rank test was performed.

Results

Population A : inferior sagittal osteotomy with hyoid myotomy and suspension (n=36)

Pre-surgical complaints and symptoms. AJl patients complained of heavy snoring at night and 35 reported excessive daytime sleepiness (EDS); 33 had disrupted nocturnal sleep; 35 had apnoea observed during sleep by a spouse; 26 had nocturia; 25 had regular night sweat; 18 talked in their sleep; 13 had night terrors; 3 walked in their sleep; 1 had weekly to monthly noc­turnal enuresis; 13 woke up regularly with headaches;

6 complained of daily morning confusion; 9 had move­ments during sleep, including 5 with head-banging; 15 complained of hearing loss; and 15 were receiving hypertensive medication.

Pre-surgical cephalometric findings. Mean SNA angle was 81.1±4.2° (range 71- 91°); mean SNB angle 79.0±3.2° (range 70-84); mean PNS-P distance 44.0±5.9 mm (range 33- 56 mm); mean MP-H distance 26.2±8.0 mm (range 10-44 mm) mean; pas distance 4.5±2.3 mm (range 1- 10 mm).

Pre-surgical nocturnal polygraphy. Sleep disturbance was present with an increased percentage of Stage 1, and decreased percentage of Stage 3-4 and REM sleep. RDI and Saoz indices were abnormal, with clear vari­ation in severity within the group. No significant car­diac arrhythmias were noted in the recording with the exception of brady-tachycardia with apnoeas (table 1).

Table 1. - Population A: Inferior sagittal osteotomy with hyoid myotomy and resuspension in 36 patients (mean±so)

Variable

TST Sl S34 REM sleep Sao2 T<90% Sao2 0 -80-I RDI

Units Pre-surgery Post-surgery Statistical Significarre

min 376±58 397±53 Ns• % 42.6±19.5 32:1:14 p<0.03+ % 3.8±5.3 6.4±72 Ns• % 10.5±5.5 14.3±4.3 p<0.009• % 93.7±2.1 94.6±1.0 p<0.02H % 22.7±33.5 1.8±5.1 p<0.02H

8.0±17.8 6.4±172 p<0.02++ 48.7±25.4 24.5±22 p<0.0001H

•: matched pair t-test; H: Wilcoxon signed rank test: NS: non­significant: TST: total sleep time: Sl, S34 (NREM), and REM: sleep stages as percentage of total sleep time; Sao

2:

arterial oxygen saturation; T<90% Sao2

: percentage of to tal sleep time spent with Sao2 below 90%; 0 2-80-L: number of Sao

2 drops !>80% per hour of sleep; RDl: respiratory distur­

bance index; NREM: non-rapid eye movement; REM: rapid eye movement.

Post-surgical evaluation. At the 6 month follow-up evaluation and recording, four patients, despite greatly reduced snoring, felt little change subjectively when compared with baseline. No patient had lost weight, and three patients had gained > 10 kg weight. (Three months post-surgery, an additional patient with intermittent asthma was treated by a high dosage of corticosteroid for a serious episode and thus added significant weight increase to the severe asthmatic problem). All other patients reported "improvement", with significant de­crease of EDS and generally improved daytime activi­ties and quality of life.

Post-surgical po/ygraphic recording. As shown in table 1 and figure 4, there was an overall statistical improve­ment of nearly all monitored variables; however, the standard deviations for some of the mean values were

608 C. GUILLEMINAULT ET AL.

wide, indicating a subgroup with limited objective im­provement Subjective improvement was more moder­ate for 16 of the 36 patients. To better understand the differences between "moderate" and "good" results, a new analysis was performed, comparing the baseline presurgical data of two subgroups, whose division was based upon postsurgical polygraphic recording data (see table 2). Subjects with a postsurgical RDI ~20 and T<90% Sao

2 :s;I% were placed in the good result group,

which included 20 patients. All other subjects were in a "moderate" result group of 16 patients, even if they reported subjective improvements. 120r-----------------------------------~

110

100

90

60 Sao,

T<90% 0,-80·1 AOI

Fig. 4. - Graphic presentation of the changes in polygraphically monitored respiratory indices between pre- and 6 months post-infe­rior sagittal osteotomy with hyoid suspension (n=36). Sao1 : mean arterial oxygen saturation in percentage; T<90%: percentage of time during sleep spent with Sao

1 below 90%; RDI: respiratory distur­

bance index; 01-80-I: number of Sao2 drops ~80% per hour of

sleep: R._.,. :pre-surgery (mean); 1::::;::~@ : post-surgery (mean).

Moderate or no improvement versus good. The pre­surgically collected baseline variables of the two subgroups, i.e., RDI, the sleep indices (%SI, %S3=4, %REM sleep, TST), the Sao2 indices (n~-80-I, T<90%

Sao2 mean Sao2), the cephalometric variables (pas, MP-H, SNA, SNB, PNS-P), age, and BMI were com­pared, using non-parametric Mann-Whitney U statistics. RDI (p<0.007) and 0 2- 80-I (p<0.02) for the two groups differed to a statistically significant degree, i.e. the pre-surgical RDI was clearly higher in the subjects with "good" results, who tended pre-surgically to pres­ent more drops <80% Sao2 than the subjects with "mod­erate" results. None of the other variables investigated, in particular the cephalometric variables, was statisti­cally significant. The only mild trend involved BMI: the "good" results group was heavier than the "moderate" results group (X= 32.7±7 vs 29.1±3.5, p<0.09). Surpris­ingly, statistical comparison indicated that patients with a more severe disorder, a<> defined by RDI and several Sao

2 indices derived from polygraphy, generally

had better results than patients with mild problems (table 2). Complications of the procedure. Since this surgical procedure is also performed as step I of maxilla­mandibular hyoid advancement, complications noted in the 54 patients following this surgery are grouped to­gether here.

Patients undergoing UPPP simultaneously with the procedure presented the usual discomfort seen with this surgery, whilst patients who had previously undergone UPPP complained much less of local pain during the ten initial post-surgical days. Nasal reflux with fluid intake was observed in all patients during the immedi­ate post-surgical period after UPPP, but was not seen in patients who had had UPPP several months prior to the mandibular surgery. Although all patients experi­enced transient mental nerve paraesthesia, none had permanent paraesthesia at the 6 month follow-up. Oedema of widely varying severity was noted during the first few days, but was not necessarily more sig­nificant than that noted with UPPP alone, as shown by systematic cephalometric roentgenograms.

Table 2. - Results of inferior sagittal osteotomy with hyoid myotomy and resuspension: "Good" versus "Modest" groups (mean ±so)

Variable Units "Good" results Wilcoxon "Modest and no Wilcoxon "Modest" Wilcoxon SRT* improvement" results xx SRT* resultsxxx SRT*

group (n=20) group (n=16) group (n,12)

Pre-surg Post-surg Statistical Pre-surg Post-surg Statistical Pre-surg Post-surg Statistical signil:icaoce signifi~ significmre

TST min 373±56 399±55 p<0.13 (Ns) 400±47 399±51 NS 382±59 390±54 NS SI % 47.6±21.7 26.4±8.6 p<O.Ol 36.0±15.0 36.0±16.5 NS 36.1±15 34.0±14.9 NS S3-4 % 3.6±4.7 8.2±8.2 p<0.08 (Ns) 4.0±4.7 4.1±5.7 NS 4.1±4.5 4.0±4.9 NS REM SI % 10.6±5.5 15.4±4.3 p<O.Ol 14.8±17.7 13.0±4.4 NS 14.6±11.7 14.9±5.1 NS

Sao2 % 93.0±2.6 95.0±0.3 p<O.OOl 94.7±0.4 94.3±1.6 NS 94.1±0.5 94.7±0.1 p<0.05 T<90% Sao2

% 8.0±9.0 0.56±0.2 p<0.002 1.6±2.3 3.6±7.8 NS 1.68±7.9 1.00±5.0 NS

02-80-I 15.6±22.6 0.20±0.80 p<O.Ol 0.04±0.14 1.2±4.0 NS 0.06±0.16 0.8±2.9 NS

RDI 58.7±28.2 14.0±5.9 p<0.0001 36.0±14.8 37±25.5 NS 38.5±12.2 29.8±19.5 NS

Note that the "modest results" group includes four patients who significantly increased weight post-surgery and deteriorated after the ftrst 2 months post-surgery. Most patients irrunediately post-surgery initially had a mild to moderate problem. *: Wilcoxon signed rank test; XX: includes the four patients who reported no subjective improvement; xxx: excludes the four patients who reported no subjective improvement. Abbreviations as in table 1.

OBSTRUCTIVE SLEEP APNOEA AND MANDIBULAR SURGERY 609

As with UPPP alone [18], intermittent complete and partial upper airway obstruction during sleep with Sao2 drops was noted, in association with repetitive apnoeas, in patients monitored during the ftrst four post-surgical days. The rccem systematic use of nasal CPAP imme­diately post-surgery for a mean of three weeks has avoided the above problems.

Mandibular fracture of the anterior mandibular frag­ment was not observed in the 54 patients reported here. Only two patients (out of > 100), who still await a 6 months' follow-up and are thus not reported here, experienced mandibular fracture when the osteotomy was inadvertently extended close to the alveolus. They were conservatively treated by arch bar application; the fracture in situ was not of consequence at the 3 months' follow-up. One patient had a hyoid suspension that was too superior and anterior, resulting in continuous regur­gitation and risk of aspiration pneumonia. The suspen­sion was partially released within the first few days post-surgery. At long-term (6 month) evaluation, no sig­nificant relapse, or speech or swallowing difficulties have been noted. Patients have been free of problems for the 8 months' to 3.5 years' current follow-ups.

Population B: maxillo-mandibular hyoid advancement (n=18)

?re-surgical complaints and symptoms. All patients complained of severe EDS and loud snoring at night. Frequent apnoeas had been noted by a spouse in all cases. In addition, 16 patients complained of frequent disrupted nocturnal sleep with awa.kenings; 8 had vio­lent, abnormal movements during sleep; 12 had nocturia; 13 reported heavy sweating at night; 8 had frequent headaches on awakening; 7 had daily morn­ing confusion; l1 talked in their sleep; 3 walked in their sleep; 3 presented with frequent nocturnal enuresis; 1 had recurrent night terrors; 4 complained of hearing loss; and 7 patients were on hypertensive medication.

?re-surgical cepluzlometric findings. Mean SNA was 78.1±2.7° (range 72-82°); mean SNB 73.7±3.2° (range 67-80°); mean NfP-H distance 29±6.4 mm (range 17-4 1 mm); mean PNS-P djsLancc 42.6±5.5 mm (range 35-52 mm); and mean pas distance 3.4±1.2 mm (range 1.5- Smm).

Pre-surgical nocturnal polygraphy. A significant sleep disturbance was seen, with a greatly increased percent­age of Stage 1 NREM sleep and significant decreases in percentage for both Stage 3-4 and REM sleep (table 3). The RDI was always elevated, with lowest Sao2 always occurring during REM sleep. Sao2 <80% was seen in all patients at least once during the night. Sinus arrest, in association with s leep apnoea, and last­ing 3-5 s was seen at least once in three patients. Pre­mature ventricular complexes (PVCs) were seen at a rhythm of 1-2 min during sleep in five subjects. One subject had one episode of atrio-ventricular block (Mobitz type II) in association with apnoea. All sub-

jects presented the classic brady-tachyarrhythmia seen with sleep apnoea.

Table 3. - Maxillo-mandibular hyoid advancement: pre­and 6 months post-surgical results in 18 patients (mean±so)

Variable Units Pre-surgery Post-surgery S tatistical Significarx2

TST min 406±48 397±67 NS+

S1 % 40±22.1 21±13.8 p<0.002· S3-4 % 2.7±3.7 7.1±9.9 p<0.04" REM sleep % 9.9±3.3 13.8±6.7 p<O.Ol++ Lowest Oz % 64.3±16.5 86.5±4.9 p<O.OOOJ++ Sao2

% 91.1±3.7 94.9±0.1 p<O.OOQ1++ T<90% Saoz % 14.5±11.0 0.2±0.4 p<0.0001•• Oz-80-I 19.5±24.6 0.0±0.0 p<0.007•• RDI 65.5±20.1 8.5±5.6 p<0.0001++

•: matched pair t-test; ++: Wilcoxon signed rank test; NS non­signficicant. Abbreviations as in table 1.

Post-surgical evaluation: subjective report. Six months following the last surgical procedure, BMI was not sig­nificantly different from pre-surgical measurement. Subjectively, all patients reported significantly improved daytime alertness, greater energy, the ability to cope with daily chores, the disappearance of frequent mom­ing headaches, an improved mood, an impression of being "sharper" with "better memory", and the disap­pearance of snoring, abnonnal movements and restless sleep. Three patients presented some PVCs during sleep, but well below the rate of 1- 2 per min/24 h of the pre­surgical nocturnal period. The two other PVC-positive patients had less than 50 PVCs during total sleep time. No other cardiac arrhythmias were seen.

Post-surgical po/ygraphic variables. Polygraphic record­ing results are indicated in table 3. Statistically, with the exception of a mildly decreased and nonsignificant TST, all other variables showe.:! highly significant dif­ferences. All Sao

2 indices indicated a good maintenance

of Sao2

(table 3). Pre-surgery, Pearson coefficient cor­relation had indicated significant correlation between mean Sao

2 and 0

2-80-1 (0.55); mean Sao2 and %

T<90% Sao2

(0.96); 0 2-80-1 and % T<90% Sao2 (0.87). These correlations were again found post-surgery: mean Sao

2 and (0.54); mean Sao2 and % T<90% Sao2 (-0.54);

02-80-I and % T<90% Sao2 (0.73). The correlation

coefficient between RDI and BMI following surgery was 0.46, indicating that the few persistent apnoeas during sleep were still seen in morbidly obese patients (BMI >38). Post-surgically, the elevated percentage of Stage 1 NREM sleep, an index of some sleep distur­bance, also correlated with the RDI (0.54). But the mean percentage of Stage 1 NREM sleep was highly improved statistically over the pre-surgical value. (Poly­graphic recordings a mean of 2 months after step 1 surgery, and before step 2, indicated, as expected, that sleep apnoea had not been controlled. The mean RDI was 39±26 and the mean 0 2-80-I was 8±9).

610 C. GUILLEMINAULT ET AL

120 ,....------------------,

110

100

Sao,

Lowest T<90% o,.so-• ROI

Fig. 5. - Graphic presentation of the changes in polygraphicaUy monitored respiratory indices between pre- and 6 month post­maxillary mandibular hyoid advancement (n,J8). For abbreviation see legend to figure 4. Note that "post surgery" T<90% and 0

1-80-

I are at 0 and do not appear on the figure. ~ : pre-surgery (mean); f::::M!d : post-surgery (mean).

Complications of the procedure. The potential compli­cations (i.e. nasal reflux, transient nerve paraesthesia, mandibular fracture of the anterior mandibular fragment) are not only those reported for inferior sagittal osteot­omy and hyoid myotomy, but also some that are more specifically related to step 2 of the procedure; in par­ticular, possible damage to the inferior alveolar nerve during its difficult dissection. As in population A, nasal reflux, oedema, and transient mental nerve paraes­thesia were observed in all patients during the imme­diate post-surgical period following UPPP and step 1 surgery. No significant complications were otherwise noted in this group. Paradoxically, the maxillo­mandibular hyoid advancement, i.e. step 2 of the sur­gery, leads to fewer complaints of pain and significant discomfort than are reported for UPPP. Partial facial sensory paraesthesia was noted in five patients in the period preceding the 6 month post-surgical follow-up. At this follow-up, however, there was no evidence of any of the following: velo-pharyngeal insufficiency, im­paired speech or swallowing, persistent facial paraesthe­sia, persistent pain, or significant relapse. The longest clinical follow-up has been 3 yrs, with a mean of 10 months, and this patient population has been free of any long-term complication.

Comparison of nasal CP AP and maxilla-mandibular hyoid advancement treatment. Four patients initially treated with nasal CP AP secondarily underwent max­illo-mandibular hyoid surgery. Using the Wilcoxon signed rank test, we compared the polygraphic results obtained during nasal CPAP treatment with those obtained 6 months post-surgery, selecting TST, percent­age of Stages 1, 3-4, and REM sleep, RDI, mean Sao

2,

T<90% Sao2, and 0 2-80-I for comparison. Not only were all results nonsignificant (the p value closest to indicating a trend was only p<0.109, for percentage of S 1 and S3-4 comparison), but the mean values for most variables were also very close, e.g. mean

RDI=10.9±8 vs 9.8±9, mean Sao2=95% with both treat­ments; similarly, % T<90% Sao2 and 0 2-80-1=0 with both procedures.

Conclusions

Although there are now many proposed treatments for OSAS, their indications, long-term results, and compli­cations are often poorly documented. Tracheostomy is probably the only exception to the rule [19, 20]. In addition to problems already mentioned with respect to CPAP non-compliance, a 5 yr follow-up of weight-loss trial for treatment of OSAS, also performed in our clinic, demonstrated >90% failure [20].

This is the first report to consider a large OSAS patient population submitted to maxillofacial surgery. Although the surgical techniques are not new, and have been performed for other indications [4- 12], their ap­plication to OSAS is new. The indications for surgery were based upon a careful analysis (using cephalomet­ric roentgenograms, fibreoptic examination, nocturnal polygraphic monitoring, and subjective complaints) of the anatomical abnormalities found in the upper airway of OSAS patients.

Although all 54 patients underwent inferior sagittal osteotomy (step 1 of the maxillo-mandibular surgery), the results of the two surgical procedures are different. Outside the research protocol, all patients undergoing maxillo-mandibular surgery (population B) had regular follow-ups, including polygraphic recording, between step 1 and step 2. These follow-ups preceding step 2 indicated that, in alJ cases, despite improvement com­pared with baseline, abnormal findings persisted during polygraphic recordings. Maxillo-mandibular-hyoid ad­vancement gave very good results overall (the best ob­tained by far with any surgical procedure, other than tracheostomy, performed in our clinic over the past 10 yrs) at 6 months' follow-up. In the four patients who were also initially treated with nasal CPAP, but who preferred surgery as a long-term treatment, we found that similar positive results were obtained with both procedures. Although morbid obesity was seen in our population treated with maxillo-mandibular surgery (one patient weighed 185 kg at the time of surgery), none had major lung disease or was a significant carbon di­oxide (C02) retainer, with C02 tension always <44 torr when awake and seated.

The good results at 6 months' follow-up are also of theoretical interest, as they demonstrate that action di­rected only toward upper airway anatomical factors can completely control a severe OSAS, even with signifi­cant obesity in non-C02-retainer patients.

Patients selected for inferior sagittal osteotomy and hyoid myotomy alone showed a more mixed response. For various reasons, four patients did not improve, and all four gained significant weight post-surgically. The gain in airway space may be sufficient for a certain weight, but an abrupt, marked increase over the weight at the time of surgery may again compromise the airway. As a group, subjects with "moderate

OBSTRUCTIVE SLEEP APNOEA AND MANDIBULAR SURGERY 611

improvement" were initially less severely affected and less obese than subjects considered to have had "good" results. Patient by patient analysis indicated that several of the "modest" results were seen in patients with more marked maxilla-mandibular abnormalities, i.e, with SNB angles of 74-75° (despite the fact that when the over­all cephalometric variable results were compared be­tween "good" and "moderate" groups, there was no statistical significance). Because of the mild to moder­ate clinical symptomatology and polygraphic recording data, we initially put these patients into group A. This was erroneous: inferior sagittal osteotomy with hyoid myotomy and suspension, in general, will give moder­ate results even in moderately affected patients, if the SNB angle is <76°.

However, small SNB angles and excessive BMI could not explain the total number of "modest" results. Other cephalometric variables may be indicative, but we have not been able to identify them in this study. Other fac­tors, not considered in the study, would perhaps have been indicative, e.g. degree of mild to moderate COPD, amount of nightly alcohol intake, importance of sleep deprivation, etc. It must be emphasized, however, that we did not consider these factors for group B either, and these patients had very good results from the maxilla-mandibular surgery. Finally, none of the patients reported here had a major lung disease with significant daytime blood gas derangement, a condition that we still consider to be a contra-indication for these thera­peutic surgical approaches.

Acknowkdgements: We thank B. Haycs and D. Cobasko for providing technical assistance and A. Grant for editing the manuscript.

References

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Chirurgie maxillo-mandibulaire dans les syndromes d'apnee du sommeil. C. Guilleminault, M .. 4. . Quera-Salva, N.B . Powe/l, R.W Riley. RESUME: Divers traitements ont ete suggeres lors du syn­drome des apnees obstructives du sommeil. Nous prescntons les resultatS obtenus sur 54 malades traites par chirurgie mandibulaire. 36 d'entre eux Onl ete soumis a une palato­pharyngo-plastie (PPP) associce a une osteotomie inferieure sagittale de la mandibule et a une myotomie sous-hyo'idienne avec resuspension de l'os (population A), tandis que 18 ont eu un avancement maxillo-mandibulaire et hyoi'dien (popula­tion B). Cette demiere intervention se decompose en deux parties: tout d'abord PPP-ostcotomie mandibulaire inferieure sagittale et myotomie sous-hyoi'diennc avec resuspension; puis, quelques semaines ou mois plus tard, osteotomie maxillo­mandibulaire. Lcs criteres de selection des sujets pour l'une ou !'autre de ces approches avaient ete preetablis, ainsi que ceux utilises pour apprecier les resultatS des interventions. Les reevaluations clinique et polygraphique furent realisees 6 a 8 mois apr~ la derniere intervention. Dans le groupc A, 32 sujets sur 36 furent "arncliores", mais nous estimons que 20 seulemenl repondent a tous nos cri tercs diiS "de gucrison". Par contre. tous les sujets du groupe B remplissent ces criteres. Avant toute intervention chirurgicale, 4 malades du groupe B ont ete traites par une "CP AP" nasale; chirurgie et CP AP ont

612 C. GUILLEMINAULT ET AL.

donne des resultats analogues tres satisfaisants. Les criteres de selection deduits de cette etude, les problemes, non reso­lus, associes au groupe A, Ies risques potentiels lies A ce type de chirurgie, et les complications observees, sont eux aussi

resumes. Le degre des deficiences squelettiques cranio­faciales, et particum~rement la retrognathie, est essentiel pour la selection du traitement. Eur Respir J., 1989, 2, 604--612.