Mandibular Repositioning Device (MRD) and Obstructive Sleep Apnea Syndrome.

“Maxillomandibular advancement” (MMA) surgery is widely recognized to be a highly effective surgical intervention for the treatment and management of “obstructive sleep apnea syndrome” (OSAS) in patients where “continuous positive airway pressure” (CPAP) therapy is not applicable, is intolerant, or is unsuccessful.[123]

Currently, MMA is used routinely to treat OSAS in patients with either dentofacial deformities or abnormal facial morphology. The success rate fluctuates between 90% and 97%.[45]

The objective and subjective outcomes following MMA surgery for the treatment of patients with OSAS, indicate that surgery can be highly successful and can eliminate the use of CPAP, improving the subjective outcomes and considerably decreasing the Apnea–Hypopnea Index (AHI) score.[6]

As objective measurements can be considered the pre and post operative ‘PSGs’ (polysomnographs), the airway morphology (airway volume and minimal cross-sectional area), the linear changes to ‘Pas B- Pogonion’ and the ‘PNS’ length in lateral cephalograms, in OSAS patients. The subjective outcomes are suggested by the Epworth Sleepiness Scale ‘ESS’ before and after MMA.[678]

None of the reported studies include a detailed documentation of the subjective and objective measurements of all treated patients with MMA as well as the efficacy of mandibular repositioning device (MRD) as an index for future MMA surgery.

The therapeutic efficacy of MMA in a patient can be shown by comparing the preoperative with the postoperative AHI score. Surgical success is defined by the percentage of patients with >50% reduction of the AHI to fewer than 20 events/h after the MMA surgery, whereas surgical cure is defined after the MMA surgery with AHI fewer than 5 events/h.

Suspected patients – suffering from OSAS – underwent polysomnography test, lateral cephalography, three-dimensional cone-beam computed tomography, and nasopharyngeal endoscopy. Furthermore, they underwent clinical evaluation and answered a questionnaire regarding their symptoms.

In our 3-year study, a total of 88 patients underwent polysomnography test, from which, sixty were diagnosed with OSAS with AHI >5, and CPAP was proposed to 39 patients with AHI >15. MRDs were used in 37 patients out of the total 60 patients in the list as well as in 24 patients with AHI <5 but with severe clinical symptoms.

The MRDs have been used as an alternative to CPAP and as an index for future surgery.

Our team has surgically treated 14 patients (MMA) with an average mean AHI of 23.35/h and an ESS score of 13.28/24, preoperatively, resulting to AHI of 4.34/h and ESS of 1.71/24, respectively, postoperatively. Significant parameters such as airway volume (cm3) (minimal cross-sectional area [mm2]), PAS B-Pogonion, and PNS length were calculated, and the results are shown in Table 2. It is remarkable that the mean length of PAS B-Pogonion postoperatively is <+9 mm. Overall, our results conclude to 71.42% cure rate and 92.85% success rate. In addition, none of the patients had any clinical symptoms after surgery. There are four out of 14 cases in this list that did not show surgical cure; more specifically, two out of four of these patients were over 55 years old with central sleep apnea and the other two patients presented an increased body mass index pre- and postoperatively, but all of them did not have any clinical symptoms [Tables 1–4].

Table 1

Patient demographic data

Patient number	Age (year)	Gender	MRD Preoperative	Concomitant procedure
1	41	Male	-	-
2	52	Male	-	-
3	34	Male	Yes	-
4	20	Male	-	Genioplasty
5	36	Male	Yes	-
6	46	Male	-	-
7	39	Male	Yes	Turbinectomy
8	26	Male	Yes	Turbinectomy and genioplasty
9	29	Male	Yes	Genioplasty
10	63	Male	-	Genioplasty
11	31	Male	Yes	-
12	55	Male	Yes	Genioplasty
13	20	Male	-	Genioplasty
14	29	Female	-	Genioplasty
Mean	37.21

MRD: Mandibular repositioning device

Table 4

Pre- and postoperative sleep quality

Patient number	AHI		ESS		Main symptoms
	Preoperative	Postoperative	Preoperative	Postoperative	Preoperative	Postoperative
1	16	2	12/24	2/24	Drowsiness and memory loss	None
2	7	1	9/24	1/24	Headache and disorder of concentration	None
3	25 (4 MRD)	0.68	12/24	3/24	Headache, disorder of concentration, and memory loss	None
4	45	10	19/24	1/24	Drowsiness, headache, and disorder of concentration	None
5	72 (16 MRD)	1	14/24	0/24	Drowsiness and disorder of concentration	None
6	14	2	12/24	2/24	Drowsiness and headache	None
7	19 (6 MRD)	2	9/24	2/24	Headache	None
8	52 (15 MRD)	11	12/24	1/24	Drowsiness and disorder of concentration	None
9	15 (4 MRD)	1	16/24	0/24	Drowsiness and headache	None
10	20	19	17/24	5/24	Drowsiness and disorder of concentration	None
11	9 (3 MRD)	1	14/24	1	Headache and disorder of concentration	None
12	22 (11 MRD)	9	12/24	2/24	Drowsiness and memory loss	None
13	2	0	13/24	1/24	Disorder of concentration	None
14	9	1	15/24	3/24	Drowsiness and headache	None
Mean	23.35	4.34	13.28/24	1.71/24

AHI: Apnea–Hypopnea Index, ESS: Epworth Sleepiness Scale, MRD: Mandibular repositioning device

Our findings reflect the results of the study mentioned above. MMA surgery for the treatment of OSAS can be a highly successful surgery which may result in total healing of the syndrome. The MRDs may be used as an index for future surgery especially in cases with normal facial appearance, and the full documentation of the cases before and after surgery is vital.

Table 2

Pre- and postoperative airway morphology parameters

Patient number	Airway volume (cm3)		MinCSA (mm2)		PAS B-Pogonion (mm)		PNS length (airway height) (mm)
	Preoperative	Postoperative	Preoperative	Postoperative	Preoperative	Postoperative	Preoperative	Postoperative
1	5.958	8.662	46	143	6	11	73	62
2	11.768	15.282	166	264	6	9	53	49
3	9.609	12.320	32	107	8	12	64	59
4	-	-	-	-	4	14	77	69
5	-	7.097	-	198	7	16	62	57
6	-	22.245	-	470	8	13	84	73
7	11.216	21.451	141	750	7	16	50	48
8	14.903	18.877	287	401	7	16	65	62
9	5.720	9.012	70	164	4	9	51	48
10	19.434	24.107	343	553	4	9	63	59
11	6.704	10.857	171	452	5	10	55	52
12	9.309	20.737	81	183	4	11	55	53
13	11.969	15.162	230	388	9	16	67	60
14	4.167	6.975	25	154	3	10	44	39
Mean	10.068	14.829	144.7	325.15	5.85	12.28	61.64	56.42

MinCSA: Minimal cross-sectional area, PAS: Posterior airway space, PNS: Posterior nasal spine

Table 3

Surgical treatment plan

Patient number	Maxilla advancement (mm)	Mandible advancement (mm)
1	7	10
2	9	9
3	8	9
4	-	8
5	10	12
6	7	11
7	9	11
8	9	11
9	8	8
10	10	11
11	9	9
12	9	10
13	9	8
14	6	14