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 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 5  |  Issue : 2  |  Page : 97-105

Evaluation of velopharyngeal changes and mechanisms in upper airway following maxillary advancement by LeFort I osteotomy in patients with cleft: A retrospective study


1 Department of Orthodontics, Institute of Dental Sciences, SOA University, Bhubaneswar, Odisha, India
2 Department of Oral and Maxillofacial Surgery, Institute of Dental Sciences, SOA University, Bhubaneswar, Odisha, India
3 Orthodontist, Private Practioner Hitech Dental College and Hospital, Bhubaneswar, Odisha, India
4 Department of Orthodontics, Kalinga Institute of Dental Sciences, KIIT University, Bhubaneswar, Odisha, India

Date of Web Publication26-Jul-2018

Correspondence Address:
Dr. Swati Saraswata Acharya
Department of Orthodontics, Institute of Dental Sciences, SOA University, Bhubaneswar, Odisha
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jclpca.jclpca_9_18

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  Abstract 


Introduction: Velopharyngeal dysfunction after maxillary advancement in Lefort I osteotomy may be a result of velopharyngeal insufficiency in patients with cleft. Maxillary hypoplasia is often related to a combination of congenital decrease in midfacial growth and surgical scar from cleft palate repair. Aims and Objectives: The aims and objectives of this study are to evaluate and correlate the velopharyngeal changes during and after maxillary advancement in patients with cleft after Lefort I osteotomy. Materials and Methods: Thirty Class III patients were included in this study. Maxillary advancement was done with Lefort I osteotomy. Cephalometric, nasopharyngoscope, and nasometer records were taken before, immediate postoperative and 1 year after advancement. A paired t-test was used to find the differences at P < 0.05. Results: The range of maxillary advancement was almost at mean of 9 mm. Statistical increase in the anteroposterior distance of superior, middle and inferior velopharynx, nasopharyngeal and oropharyngeal dimensions, angle of velar, and need ratio was found (P = 0.0001). There was a significant increase in nasalance scores (P < 0.041). Sagittal maxillary changes were 9.77° postadvancement. Vertical changes in maxilla, ANS, and peripheral nerve stimulation relative to X-axis (P = 0.0001, 0.0001 and 0.018) significantly increased after surgery. A significant positive correlation was seen between the amount of maxillary advancement and increase in depth of nasopharynx (P = 0.0001). Conclusions: The maxilla was advanced forward causing increased nasopharyngeal depth. There was a positive correlation between the amount of maxillary advancement and nasopharyngeal depth.

Keywords: Cleft lip and palate, flexible fiberoptic nasopharyngoscope, nasalance, nasometer, orthognathic surgery, velopharyngeal dysfunction


How to cite this article:
Acharya SS, Patnaik S, Mishra S, Padhiary SK, Gautam N, Mohanty P. Evaluation of velopharyngeal changes and mechanisms in upper airway following maxillary advancement by LeFort I osteotomy in patients with cleft: A retrospective study. J Cleft Lip Palate Craniofac Anomal 2018;5:97-105

How to cite this URL:
Acharya SS, Patnaik S, Mishra S, Padhiary SK, Gautam N, Mohanty P. Evaluation of velopharyngeal changes and mechanisms in upper airway following maxillary advancement by LeFort I osteotomy in patients with cleft: A retrospective study. J Cleft Lip Palate Craniofac Anomal [serial online] 2018 [cited 2019 Jan 20];5:97-105. Available from: http://www.jclpca.org/text.asp?2018/5/2/97/237640




  Introduction Top


Individuals with known velopharyngeal dysfunction (VPD) are treated with an interdisciplinary approach.[1] VPD in patients with cleft is seen commonly. This may be due to velopharyngeal insufficiency (VPI) (short immobile velum and increased depth of nasopharynx) in comparison to noncleft patients who have VPI (mechanical interferences), incompetence (myoneurogenic problems), and mislearning (patient has mislearned to use certain speech sounds).

Maxillary-midfacial hypoplasia and skeletal Class III are common in patients with cleft lip and palate (CLP). This is mostly related to a combination of factors such as congenital reduction in the midfacial growth and surgical scar.[1],[2] Surgical intervention with isolated maxillary Lefort 1 advancement offer improvement in terms of functional, esthetic and psychosocial benefits. Mostly, immediate surgical advancement can elicit VPI.[3],[4],[5],[6],[7]

The newest option is distraction osteogenesis (DO) which has been used to successfully correct maxillary-midfacial hypoplasia with predictable and stable results.[8],[9] DO offers the advantage of no limitation of age as a factor in patients who seek maxillary advancement. DO enhances further growth and development of the jaw (in patients where facial growth is not completed), helps in bone stability, where slow movement of maxillary bone enhances the soft tissues as facial envelop, soft palate with pharynx to adapt to the structural changes and decreases skeletal relapse.[10],[11] However, there are many drawbacks of DO-like once a uni-vectorial device is placed, the vector of distraction cannot be altered along with any rotational advancements. Maxillary cant is observed which is corrected with an intermaxillary splint having elastics later. Second, the duration of callus formation and consolidation period is usually 3–4 months which is challenging for the patient. Third, GA has to be given twice in case of an internal distractor which is even more challenging.[12],[13]

Sometimes not preferring DO for cases is a combined decision of the team and patient. Some patients do not prefer wearing a distraction device. Considering the above factors Lefort I osteotomy for maxillary advancement was planned in our study.

Literature review

Changes in speech and velopharyngeal function following the advancement of maxilla has been described by few authors and yielded varied results.[12],[13] Some authors have reported that the deterioration of patients post maxillary advancement. Another study reveals the deterioration of hypernasality which depends on the location of posterior pharyngeal wall with rotation of palatal plane.[14] The effect of maxillary advancement on changes in speech still remains questionable. Certain sibilant sound errors demonstrated in occlusal defects may be rectified spontaneously postorthognathic surgery.[15],[16],[17],[18],[19] Hence, VP competence can be compromised in patients with borderline VP closure who had maxillary advancement of 10 mm or greater.[14],[20]

The incidence of VP incompetence in patients with cleft who require pharyngoplasty has been reported to be 9%.[21] Authors have reported that mostly in cleft patients the incidence of hypernasality and impaired VP function is seen post maxillary advancement with orthognathic surgery.[22],[23] Some investigators have reported that there were no changes in VP function postsurgery.[24] Many diversities have been observed due to different degrees of advancement, direction of positioning, period of observation, and evaluation methods. In certain patients, VP was evaluated through video fluoroscopy [25] and lateral cephalograms.[26] These are practical and reliable methods although two-dimensional imaging is a valid representation of nasopharyngeal anatomy.[25]

Studies have shown significant findings of nasopharyngeal obstruction with good statistical correlation,[13] and evaluation of speech [27] with good accuracy.[28] Some authors have found the changes occurring in anatomy of VP after maxillary advancement.[29],[30]

Hence, these compensatory changes do not give a clear picture of status of velopharynx and the queries of a possible correlation between degree of maxillary advancement and deterioration of velopharynx remains unclear.

The aims and objectives of the study were to evaluate and to correlate the changes during and after maxillary advancement in patients with cleft after Lefort I osteotomy.


  Materials and Methods Top


Patients

This retrospective study was conducted on 30 CLP patients who underwent maxillary advancement by Lefort I osteotomy. The patients had a mean age of 19.13 + 4.7 years. Among 30 patients, 15 patients were males, and 15 patients were females. 22 patients had a diagnosis of unilateral CLP, and the rest had a diagnosis of bilateral CLP from 2014 to 2018. All the patients exhibited maxillary midface hypoplasia preoperatively with a negative overjet exceeding 7 mm. All patients showed presurgery pharyngeal flaps (PFs) in place. Some of these patients have ever been subjected to early maxillary face mask therapy and alveolar bone grafting has been done for all patients.

A Lefort 1 osteotomy was done; maxilla was down fractured to ensure the mobility. Maxillary advancement of mean 7 mm was done. Cephalometrics was used as guidelines for measuring the maxillary advancement.

No PFs were cut during maxillary advancement in any patients.

Lateral cephalograms, nasometer, and nasopharyngoscopy were used to evaluate the patients at three stages: preoperatively (T0), immediate postsurgery (T1), and 1 year postsurgery (T2). The progress of a case is illustrated in the figures [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11].
Figure 1: Cephalometric parameters for the airway and soft tissue. Landmarks: Ad1: Intersection of the peripheral nerve stimulation-Ba line with posterior pharyngeal wall; ad2: Intersection of a perpendicular line drawn from peripheral nerve stimulation to BaS line with posterior pharyngeal wall; H: Point of intersection of a perpendicular line from peripheral nerve stimulation to Ba-S line with the cranial base; Ptm: Pterygomaxillary fissure; upper pharyngeal wall; nasopharynx: Intersection of the palatal plane with posterior pharyngeal wall; middle pharyngeal wall; oropharynx: Intersection of the line from point U to posterior pharyngeal wall; lower pharyngeal wall; hypopharynx: Intersection of the line from point “V” with posterior pharyngeal wall;. U: Tip of uvula; T: The tip of the tongue; V: Intersection of the epiglottis and the base of the tongue. Linear and angular parameters. Lower airway thickness: peripheral nerve stimulation to ad1; lower adenoid thickness: Ad1 to Ba; complete lower sagittal depth of bony nasopharynx: peripheral nerve stimulationto Ba; upper airway thickness: peripheral nerve stimulation to ad2; upper adenoid thickness: Ad2 to H; complete upper airway thickness: peripheral nerve stimulation to H; posterior sagittal depth of the bony nasopharynx: Ptm to Ba; total vertical airway length: peripheral nerve stimulation-V; nasopharyngeal depth: Peripheral nerve stimulation to UPW; oropharyngeal depth: U to middle pharyngeal wall; hypopharyngeal depth: V to lower pharyngeal wall; velar length: Peripheral nerve stimulation to U; velar thickness: Maximal thickness of soft palate measured perpendicular to peripheral nerve stimulation-U line; tongue length: T to V; tongue height: The perpendicular distance from the most superior point of the tongue to the V-T line; velar angle: ANS-peripheral nerve stimulation-U; need ratio: Nasopharyngeal depth/velar length

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Figure 2: Cone beam computed tomography was used for assessment of velopharyngeal status, observation of hard and soft tissues, though the reliability of two-dimensional images has been questionable for a valid representation of the actual nasopharyngeal anatomy

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Figure 3: Pretreatment extraoral

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Figure 4: Pretreatment intraoral

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Figure 5: Pretreatment radiographs

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Figure 6: Presurgery records

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Figure 7: Facebow transfer, mock surgery, occlusal splints, surgery

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Figure 8: Postsurgery records

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Figure 9: Posttreatment extraoral

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Figure 10: posttreatment intraoral

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Figure 11: posttreatment radiographs

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Cephalometric analysis

All tracings were manually done using lateral cephalograms. Reference points and landmarks were marked, giving linear and angular measurements [Figure 1]. A 7° line below the SN line and a perpendicular line through sella was used as X, Y coordinator system. All cephalometric films were taken in occlusion and velum at rest. The X-ray magnification was 10%. The sagittal movement of point A, ANS and peripheral nerve stimulation (PNS) were measured from each landmark to the Y-axis. To estimate the error of methods, 20 randomly selected radiographs were traced while measuring was done twice within a week. The mean values from first tracing and the mean values of second were applied to a formula called as “Dahlberg's formula.”[31],[32] For linear measurements, 0.45 mm was set as the method error and angular it was 0.5°.{Figure 1}

Nasometric analysis

A nasometer, model 6450, a microcomputer-based system was used. Nasalance scores were recorded and consisted of sentences containing nasal sounds for identifying decreased nasalance and others consisting of sentences with reduced nasal sounds. The resultant final signal is the ratio of nasal to nasal and oral acoustic energy. The ratio is a multiplication by 100 and is termed as nasalance score. Hypernasality and hyponasality were termed using separate five-point scales where 0 = normal, 1 = mild, 2 = moderate, 3 = severe, and 4 = most severe.[18]

Flexible fiberoptic nasopharyngoscope

The nasopharyngolaryngoscopy model (3.8 mm, 300 mm length, adjustable ocular angle of view 85°, angle of movement 150° including light guide, and transport case was used). Three judges were there to assess the video recordings. Velopharyngeal valve movements were recorded while the patients repeated all the vowels and certain syllables such as/pa/,/ta/, and/ka/for a repeated number of times. Velum movements along with lateral posterior pharyngeal walls were traced with monitor. The scoring for each movement was done from 0 to 4 where 0 is the resting or breathing position, two is half the distance of corresponding wall, and 4 is the maximum movement reaching and touching the opposite wall.[22]

Statistical analysis

Data was analyzed using a computed program, SPSS, version 17.0 South Asia (P) Ltd. Bangalore, India. Descriptive statistics were calculated to be presented as mean + standard deviation. Paired Student's t-test was done to compare between means of two-related groups of numerical data i.e., changes in the nasometer measurements before surgery (T0), after surgery (T1), and after retention (T2). The Pearson correlation coefficient test was used to correlate various parameters of the airway correlation between A and Y and other variables. P < 0.05 was considered statistically significant.


  Results Top


Cephalometric measurements

The parameters relating to sagittal maxillary changes were 9.77° at SNA, 8.3 mm at point A, 10 mm at ANS, and 9.3 mm at PNS. The vertical changes in maxilla, at position point A, ANS, and PNS points relative to X-axis increased significantly (P = 0.0001, 0.0001, and 0.018, respectively. There is a mean increase in SNB angle, FMA, mandibular Plane to SN, and PP to SN angles which was not significantly statistically [P = 0.800, 0.649, 0.528, and. 834 respectively; [Table 1]. There was a significant increase of depth of nasopharynx and oropharynx (P = 0.0001) while there was no change observed in hypopharynx (P = 0.868). Velar angle and need ratio were recorded and was statistically significant (P = 0.0001). Soft palate showed no significant changes [Table 2]. There was no significant cephalometric changes from T1 to T2 except for the velar angle (P = 0.05).
Table 1: Changes in the skeletal measurements

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Table 2: Changes in the pharyngeal airway passage and soft tissue

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Nasometer

There was significant increase in the mean nasalance score after oral text reading [P = 0.041, [Table 3]. In the five-point scales of hypernasality, 13 patients showed deterioration of hypernasality. Nine patients had same scores and 8 patients showed some improvement in hypernasality [Table 4]. There was a significant increase in mean nasalance score (P = 0.007 and 0.777) at T1 and T2, respectively [Table 3]. Some patients showed a postoperative decrease in hyponasality [Table

4].
Table 3: Changes in the nasometer measurements before surgery, after surgery, and after retention

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Table 4: Judgments of nasal resonance using a 5-point scale (0=normal; 1=mild; 2=moderate; 3=severe; 4=very severe)

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Flexible fiberoptic nasopharyngoscope

The mean increase in motion of palate, left, and right pharyngeal walls between T0 and T1 were not statistically significant (P = 0.102, 0.270 and 0.669, respectively). There were no statistically significant changes observed between T1 and T2 [Table 5].
Table 5: Changes in nasopharyngoscopy before surgery, after surgery, and after retention

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Correlations

In two patients, there was deterioration of hypernasality postoperatively. However, there was significant correlation between pre-PF and post-treatment hypernasality using Pearson's Chi-square values [Table 6]. There were no correlation between soft-tissue length and skeletal movement along with age of the patient. No correlation was found between change in velar angle or skeletal movement or age of patients. No correlation statistics between soft palate length changes and amount of skeletal movement. The amount of forward skeletal movement correlated significantly with the postoperative hypernasality (P < 0.01).
Table 6: Correlation between A-Y and other variables

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  Discussion Top


Lateral cephalograms and computed tomograms [Figure 1] and [Figure 2] were used for assessment of velopharyngeal status, observation of hard and soft tissues, though reliability of two dimensional images has been questionable for a valid representation of the actual nasopharyngeal anatomy. Some studies have explained about pharyngeal airway space measured by cephalograms with three-dimensional computed tomography scan.[21],[33] The time point and frequency of recording and ethical permission for tomographic scans were taken. The protocol of imaging used was a 12-in field of view to include entire facial anatomy. Axial slice thickness was 0.3 mm, and voxels were isotropic. However, unlike conventional cephalograms, three dimensional imaging has less inherent distortion of the anatomical structures.[34]

Cephalometric analysis of sagittal and vertical positions of maxilla showed considerable significant changes after surgery. The depth of nasopharynx and oropharynx increased significantly. The reason may be due to the forward movement of posterior nasal spine and soft palate with maxilla during Lefort I osteotomy. There was increase in depth of nasopharynx by a 1:1 ratio with bone movement post maxillary distraction in cleft patients as mentioned by some authors.[33] The length of soft palate remains unaltered which is quite parallel to the increase in need ratio (1.14), hinting borderline VPI. Some studies reported 0.4 mm lengthening of soft palate per mm of advancement of maxilla. This diversity may be due to various degrees of advancement, types of patients, surgical techniques, and observation periods.

There was a prominence of change in velar angle. We found that increase in soft palate inclination following 9 mm of maxillary advancement. Some authors found change in velar angle of 2°/mm of maxillary advancement. Other authors found increase in velar angle of 1.6°/mm of advancement of the maxilla. In the present study, before surgery, 89% of patients had nasalance scores for reading of oral text above normal limit.[21] Fifteen of 30 patients (45.3%) had deterioration in hypernasality postdistraction which indicated decreased speech intelligibility and worsening of speech. This effect might be due to greater increase of pharyngeal depth than velar length in compromised VP closure. Other studies showed increase in hypernasality postmaxillary advancement in cleft patients.[21],[34] In agreement with our results, few previous studies have contributed to the worsening of hypernasality in those patients who have experienced abnormal preoperative hypernasality before advancement procedures.[23],[24] This is a clear indication that maxillary advancement may contribute to any previously existing hypernasality having a cleft.

The presence of presurgical PF decreased the degree of resultant postsurgery hypernasality and hence coincides with previous studies.[24] Fifteen patients maintained the same degree of hypernasality and six patients showed some improvement from moderate-to-mild hypernasality. The increase in the length of velum and increase in velar angle achieved some kind of muscular compensatory activity. The increase in velar angle was absolutely a result of soft-tissue palate stretching which helped in maintaining vertical position of soft palate and is significantly considered to be a part of compensation in VP mechanism.[26]

Some authors [30] have specified and reported that there are few percentage of subjects with cleft who had nasal airway obstruction. In our cases, 25% (10/30) of patients had presented nasalance values in the reading of nasal text below normal limit predistraction. Hyponasality was improved in many patients, 70% (5/6). There were no patients who experienced increase of hyponasality as a result of advancement. This finding also is supported by many studies by various authors [35] who suggested maxillary advancement increases space of nasopharyngeal region, favors nasal respiration and decreases nasal resistance.

The nasopharyngoscopic results revealed that all of the patients had VPI preoperatively. The reason may be due to cicatrization from previous palatal repair surgery. There was no increase in soft-tissue palate or lateral pharyngeal wall movements postsurgery. These findings were documented by various authors in their studies [36] who suggested a widening of gap between velum and posterior pharyngeal wall postadvancement in patients with borderline closure pretreatment. Whereas, in some studies, authors mentioned that its not possible for maxillary advancement to encourage velopharyngeal movement.[37] They have mentioned that intraoral observation is not enough to decide velar movements.[38]

Post Le Fort I osteotomy, in one case, mild mucosal necrosis was encountered in the upper anterior region and then palatal mucosa in one case was detached during surgery. Both these complications were hence improved by postoperative cleaning and oxygen therapy.

In agreement with the correlation results, some studies suggest that there was a significant positive correlation between the amount of forward skeletal movement and post advancement pharyngeal depth and hypernasality.[35] Future prospective, longitudinal studies for DO and Lefort I can be done which is the scope of this study.


  Conclusions Top


  • The maxilla was advanced forward causing increased nasopharyngeal depth and compromised VPF
  • There was a positive correlation between the amount of maxillary advancement and nasopharyngeal depth
  • No significant relapse was observed in the skeletal position of maxilla, nasopharyngeal measurements, and function during follow-up.


Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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