Is Orthognathic Correction with TMJ Preservation A Stable Treatment Option for Patients with Juvenile Idiopathic Arthritis?

Abstract

Purpose

The purpose of this study was to evaluate the long-term skeletal stability of orthognathic correction of dentofacial deformities secondary to juvenile idiopathic arthritis (JIA) in individuals without total alloplastic joint reconstruction.

Materials and Methods

The investigators designed and implemented a retrospective case series of patients diagnosed with JIA who underwent bimaxillary orthognathic surgery. To evaluate the long-term skeletal changes, the maxillary palatal plane to mandibular plane angle, anterior facial height, and posterior facial height measurements were evaluated through cephalograms.

Results

Six patients met inclusion criteria. All subjects were female (mean 16.2 years). Four patients demonstrated < 1° of change of the palatal plane to mandibular plane angle, and all patients had < 2° of change. Three patients had < 1% change in the anterior to posterior facial height ratio. Three patients demonstrated relative posterior facial shortening compared to anterior facial height (< 4%). No patients developed postoperative anterior open-bite malocclusion.

Conclusion

Orthognathic correction of the JIA DFD deformity with TMJ preservation is a viable modality to improve facial esthetics, occlusion, upper airway and speech swallowing and chewing mechanisms in select patients. The measured skeletal relapse did not affect the clinical outcome.

Introduction

Juvenile idiopathic arthritis (JIA) is the most common pediatric rheumatologic condition [1]. JIA is an arthritis of unknown etiology that presents before the age of 16 with joint pain, swelling, limited range of motion, and warmth that persists for at least 6 weeks [2]. The temporomandibular joint is involved in 12–80% of children diagnosed with JIA [3–7]. When followed to adulthood, condylar deformities and/or erosions exist in 61% of those with JIA [8]. JIA patients may develop a dentofacial deformity (DFD) secondary to restricted mandibular condylar growth and pathologic resorption that manifests as mandibular retrognathia with loss of posterior facial height and an anterior open-bite malocclusion [9, 10].

The DFD contributes to a reduced quality of life, obstructive sleep apnea, and difficulties in speech, swallowing, and chewing [7, 11]. Surgical correction is indicated in those with a DFD to restore normal head and neck functions such as breathing, swallowing and chewing; however, there is limited evidence to support the method of reconstruction [12]. The surgical reconstruction remains heterogeneous although recent algorithms have attempted to standardize through classification of temporomandibular joint (TMJ) function and DFD severity [12, 13]. For those with adequate TMJ function and controlled or quiescent TMJ symptoms, orthognathic correction with TMJ preservation (without concomitant TMJ surgery) often requires counter-clockwise (CCW) rotation of the maxillomandibular complex and stability concerns exist [14–17]. A recent systematic review by Frid et al. reported extrapolated evidence to support orthognathic surgery with joint preservation in JIA patients with controlled or quiescent JIA [12]. While some advocate for total alloplastic joint reconstruction of the TMJs in individuals with JIA in an effort to restore posterior facial height and limit potential relapse, to date, no studies have demonstrated the long-term benefit of total joint replacements (TJR) as compared to native condyles. Furthermore, TJR should be used cautiously in skeletally immature patients [12].

The purpose of this study was to evaluate the long-term skeletal stability (> 6 months) of orthognathic correction of dentofacial deformities secondary to JIA in individuals without total alloplastic joint reconstructions. The hypothesis is, for select patients with a dentofacial deformity secondary to JIA, does orthognathic correction provide a stable reconstructive option? The specific aims are: 1) to identify and quantify the number of individuals who underwent orthognathic correction for DFDs secondary to JIA; 2) report preoperative skeletal deformity as measured through lateral cephalometric analysis and planned surgical movements to provide skeletal correction; and 3) report long-term (> 6 months) stability of surgical correction.

Materials and Methods

The investigators designed and implemented a retrospective case series. The study sample was derived from a population of patients referred for evaluation from the Department of Pediatric Rheumatology at Children’s of Alabama with the diagnosis of juvenile idiopathic arthritis who underwent orthodontic therapy and underwent orthognathic surgery that at a minimum included a Le Fort I maxillary osteotomy and bilateral sagittal ramus osteotomies with CCW rotation of the maxillomandibular complex between 2017 and 2018. All treatment planning and surgeries were performed by the same surgeon (PDW). All cases were planned through virtual surgical planning (3D Systems, Rock Hill, SC) with intermediate and final splint CAD/CAM fabrication. All osteotomies underwent rigid fixation. All patients were referred from pediatric rheumatology, and their disease was stabilized on systemic medications prior to clearance for surgery. No patients demonstrated signs or symptoms of active TMJ disease at time of operation and all patients underwent preoperative and postoperative orthodontic treatment. Lateral cephalometric radiographs were obtained prior to surgery (T₁), within 1 month after surgery (T₂), and at a minimum, > 6 months after the date of surgery (T₃). All were digitized through Dolphin Imaging (Chatsworth, CA), identifying the standard cephalometric points. IRB approval was granted through UAB: IRB-300000795.

Planned surgical movements were recorded as maxillary and mandibular movements. Maxillary movements included (linear) anterior–posterior, lateral, and vertical positional changes as measured at the mid-incisal point. Maxillary occlusal cant (angular) changes were recorded at the mesiobuccal cusps of the maxillary first molars, and the change in maxillary occlusal plane (vector) was defined as a triangle passing through the incisal midpoint and both mesiobuccal cusps of the maxillary first molars. The mandible position was determined through planned final occlusion and recorded as anterior–posterior (linear) measurements at the level of the mandibular incisors.

To evaluate the long-term skeletal changes, the maxillary palatal plane to mandibular plane angle (PP-MP), anterior facial height, and posterior facial height measurements were recorded. Stability was defined as no greater than 1º or 1 mm of change between T₂ and T₃ measurements.

Results

Over the two-year study period, six patients met inclusion criteria. All subjects were female, and the mean age at surgery was 16.2 years. All subjects underwent a one-piece Le Fort I osteotomy and bilateral sagittal ramus osteotomies; four also underwent an osseous genioplasty (Table 1).

Table 1.

Patient demographics

	Gender	Age at Surgery	Length of Follow-Up	Surgery
Pt 1	Female	16 yr 7 mo	1 yr 7 mo	Le Fort I, BSSO
Pt 2	Female	16 yr 6 mo	1 yr	Le Fort I, BSSO, Genioplasty
Pt 3	Female	16 yr 5 mo	11 mo	Le Fort I, BSSO, Genioplasty
Pt 4	Female	16 yo 2 mo	1 yr 5 mo	Le Fort I, BSSO, Genioplasty
Pt 5	Female	17 yo 7 mo	2 yr 6 mo	Le Fort I, BSSO
Pt 6	Female	15 yo 4 mo	3 yr 1 mo	Le Fort I, BSSO, Genioplasty

Yr, year; Mo, month; Le Fort I, Le Fort I osteotomy; BSSO, bilateral sagittal ramus osteotomies; Genioplasty, osseous genioplasty

Preoperatively, all patients demonstrated a below normal SNB and a steeper than average maxillary occlusal plane angle. Five of the six patients were with a steep mandibular plane angle relative to SN. All patients had below average anterior and posterior facial heights; however, only four patients demonstrated a below average posterior to anterior facial height ratio (Table 2).

Table 2.

Overview of preoperative cephalometric measurements (T1)

	Pt 1	Pt 2	Pt 3	Pt 4	Pt 5	Pt 6	Norm (Std Dev)
SNA	87.4	74.0	87.0	82.2	73.8	86.0	82.0° ± 3.5°
SNB	78.6	68.9	76.6	73.1	74.0	79.0	80.9° ± 3.4°
ANB	8.8	5.1	10.4	9.1	-0.2	7.0	1.6° ± 1.5°
MP-SN	35	54.7	40.2	44.2	48.5	27.9	33.0° ± 6°
Occlusal Plane to SN	20.3	25.8	21.7	18.6	26.7	15.1	14.4° ± 2.5°
Anterior Facial Height (N-Me)	105.1	114.2	112.2	98.3	119.1	98.3	141.3 ± 5.5 mm
Posterior Facial Height (S-Go)	66.6	60	65.4	53.2	64.2	68.1	74.0 ± 5 mm
PFH/AFH	63.4	52.5	58.3	54.1	53.9	69.3	62–65%
PP-MP	27.2	44.8	32.8	34.0	42.1	18.0	25° ± 6°

SNA, angle between sella, nasion, and A point; SNB, angle between sella, nasion, and B point; ANB, angle between A point, nasion, and B point; MP-SN, angle between mandibular plane (menton to gonion) and plane passing through sella and nasion; Occlusal Plane to SN, angle between maxillary occlusal plane (incisal edge of the most prominent maxillary incisor to the mesiobuccal cusp of the maxillary first molar); Anterior Facial Height (AFH), distance, in millimeters, between nasion and menton; Posterior Facial Height (PFH), distance in millimeters between sella and gonion; PP-MP, angle between the palatal plane which passes through the anterior and posterior nasal spines and the mandibular angle

The extent of presurgical dentofacial deformity was also documented through planned surgical skeletal change required to correct the existing deformity (Table 3). All patients were planned for 2–3 mm of maxillary horizontal advancement. No patients required maxillary transverse widening and all were planned for CCW of the maxillomandibular complex. Planned mandibular horizontal advancement as measured at mandibular incisor midpoint ranged from 4 to 14 mm.

Table 3.

Subjects’ planned skeletal change

	Maxillary Horizontal Advancement	Maxillary Incisor Vertical Change	Maxillary to Facial Midline Change	Pitch Correction	Cant Correction	Maxillary Transverse Widening	Mandibular Horizontal Advancement
Pt 1	+ 2 mm	− 1 mm	0.75 mm to right	CCW	0.5 mm	0 mm	+ 7.3 mm
Pt 2	+ 3 mm	− 2 mm	No change	CCW	1.6 mm	0 mm	+ 13.8 mm
Pt 3	+ 2 mm	− 2 mm	0.5 mm to right	CCW	No change	0 mm	+ 4.8 mm
Pt 4	+ 2 mm	− 1 mm	No change	CCW	1.4 mm	0 mm	+ 5.9 mm
Pt 5	+ 2 mm	− 2 mm	No change	CCW	1.3 mm	0 mm	+ 7.1 mm
Pt 6	+ 2 mm	0 mm	1 mm to left	CCW	3.4 mm	0 mm	+ 4 mm

Maxillary horizontal advancement, vertical change, and midline change as measured at the maxillary incisor midpoint. Pitch correction measured as incisor midpoint relative to mesiobuccal cusps of maxillary first molars. Cant correction and transverse widening measured at level of mesiobuccal cusps of maxillary first molars. Mandibular horizontal advancement measured at the mandibular incisal midpoint

Long-term stability was evaluated through angular and linear cephalometric measurement changes from T₂ to T₃. Four patients demonstrated less than 1 degree of change of the palatal plane to mandibular plane angle, all patients had less than 2 degrees of change (Table 4). Three patients had less than 1 percent change in the anterior to posterior facial height ratio during this time frame. Three patients demonstrated relative posterior facial shortening compared to anterior facial height (< 4%); however, no patients demonstrated a postoperative anterior open-bite malocclusion (Table 5).

Table 4.

Palatal plane to mandibular plane angle

	Pt 1	Pt 2	Pt 3	Pt 4	Pt 5	Pt 6
T2 PP-MP°	28.8°	40.9°	28.9°	42.3°	42.4°	21.8°
T3 PP-MP°	27.6°	40.1°	28.6°	40.4°	43°	22.7°
Δ T3−T2	− 1.2	− 0.8	− 0.3	− 1.9	0.6	0.9

PP-MP, angle between the palatal plane which passes through the anterior and posterior nasal spines and the mandibular angle

Norm PP-MP° (25° ± 6°)

Table 5.

Anterior and posterior facial height measurements

	Patient 1	Patient 2	Patient 3	Patient 4	Patient 5	Patient 6
T2 AFH	111.2	116.2	111.4	113.4	116.7	107.4
T2 PFH	68.9	63.2	64.7	57.8	62.4	71.5
T2 PFH/AFH	62.0	54.4	58.1	51.0	53.5	66.6
T3 AFH	111.3	119.5	110.7	113.5	116.5	106.5
T3 PFH	69.9	61.8	65	57.1	60.9	66.7
T3 PFH/AFH	62.8	51.7	58.7	50.3	52.3	62.6
Δ T3−T2	0.8	− 2.7	0.6	− 0.7	− 1.2	− 3.9

Anterior Facial Height (AFH), distance, in millimeters, between nasion and menton; Posterior Facial Height (PFH), distance in millimeters between sella and gonion, Norm PFH/AFH: 62–65%

Discussion

The purpose of this study was to evaluate the long-term skeletal stability of orthodontic therapy with orthognathic correction of dentofacial deformities secondary to JIA in individuals without TJR. Our aims were to quantify the preoperative skeletal deformity and report long-term stability of the surgical correction. Preoperatively, all patients demonstrated mandibular retrognathia with shortened anterior and posterior facial heights; however, only four (67%) had shortened posterior facial heights relative to anterior facial height. All patients required bimaxillary orthognathic surgery with CCW rotation and mandibular advancement to correct the existing skeletal deformity and demonstrated long-term clinical stability (i.e., no anterior open-bite malocclusion).

To date, there are few studies reporting orthognathic surgery with TMJ preservation outcomes in individuals with JIA [18–22]. Only four of the studies report on bimaxillary surgery [18–20, 23]. Our results align well with those of Leshem et al. and Oye et al., skeletal relapse was minimal, there were no exacerbations of TMJ arthritis, and no patients developed an anterior open-bite malocclusion [19, 20]. Leshem reported on 8 (6 bimaxillary) patients with quiescent TMJ disease, with two patients experiencing a return of open-bite malocclusion at 36 months of follow-up [20]. Oye et al. reported on nine patients, with one undergoing bimaxillary surgery and the remaining undergoing bilateral sagittal ramus osteotomies [19]. Their report documented a mean relapse of 2.3 mm after average BSSO advancement of 5.3 mm in 16 patients with substantial postoperative reduction in patient-reported TMJ pain.

The limitations of this manuscript merit discussion as to best frame the results. This study analyzes a small sample size due to the rarity of the DFD; however, the sample size is similar to the currently published JIA DFD reports [18–23]. A second limitation is the subjective definition of controlled or quiescent TMJ disease. All patients demonstrated the absence of clinical signs or symptoms that would be used to diagnose a patient with TMJ JIA active disease; furthermore, no patient demonstrated clinical or radiographic progression of their DFD prior to surgery.

Conclusion

Orthodontic therapy with orthognathic correction of the JIA DFD deformity with TMJ preservation is a viable modality in select patients. The amount of measured skeletal relapse did not significantly affect the clinical outcome. This study demonstrates long-term stability in select patients. The findings of this study convey the need for larger, multicenter studies to determine the long-term stability of orthognathic correction in the JIA DFD patient.

Author’s Contribution

BEK; PDW was involved in concept and design of the study and drafting of the manuscript. CHK was involved in interpretation and analysis of data and drafting of the manuscript. VHB was involved in data acquisition. BEK contributed to data acquisition. PDW gave the final approval for submission.

Declarations

Conflict of interest

All authors declare that they have no conflict of interest with regard to the study design, drafting and subsequent publication of the article and have not received any funding/grant for the data collection, analysis and drafting of the manuscript.

Ethical Approval

IRB approval was granted through the University of Alabama at Birmingham, Birmingham, AL: IRB-300000795.