Original Article

Rapid Maxillary Expansion Effects on Nocturnal Enuresis in Children A Follow-up Study

Ulrike Schu¨tz-Franssona; Ju¨ri Kurolb ABSTRACT Objective: To assess the effects of 10–14 days of rapid maxillary expansion (RME) on nocturnal enuresis (NE) in children who have long-standing resistance to medical therapy and to evaluate the long-term success rate after 10 years. Materials and Methods: Twenty-three children with NE, aged 6–15 years old (mean age ⫽ 10), who wet their bed almost every night and had never been dry were referred from pediatric specialists. Mean RME was 6.5 mm (range ⫽ 5–8), but only 7 of the 23 patients had lateral crossbites. Rhinomanometric measurements were taken before and after RME, and patients were interviewed 10 years after treatment. Results: Positive effects of RME were observed in nearly 50% of the patients within 1 month of treatment: six were completely dry and five had notable improvements. Relapse in the overexpanded arches to a normal transversal occlusion was noted within 1 year. No correlation was found between success and improved airways, familial heritage, school performance, or other social factors. Younger children responded better to the treatment. Results were stable at the 10year follow-up, and no adverse reactions were reported. Conclusion: Orthodontic RME is a new option for treating children with NE who are resistant to medical therapy; the treatment has no adverse side effects. KEY WORDS: Nocturnal enuresis; Rapid maxillary expansion

INTRODUCTION

mopressin, which is a vasopressin analogue.2 Tonsillectomy and adenoidectomy have also been reported to improve or cure enuresis as a side effect.3–9 The exact mechanism is unclear, however. According to several case reports and studies, treatment of upper airway obstruction seems to influence enuresis. It is noteworthy that pediatric reviews of enuresis have not stressed this possibility.1,2 In a retrospective study, Timms10 found that 10 children treated with rapid maxillary expansion (RME) later reported cessation of enuresis. Another study11 reported an immediate cure or improvement in seven children in a prospective study of 10 therapy-resistant children with NE who underwent 10–14 days of treatment with RME. All children were examined at the hospital, and none of the 10 children had any ear, nose, and throat (ENT) problems or anatomic problems of the urinary tract. The children wet their beds every night, sometimes several times. Various mechanisms behind the effects were discussed, including reductions in nasal resistance (mean ⫽ 33%). Based on a questionnaire at the 4-year follow-up, the researchers concluded that orthodontic RME treatment could have an immediate positive effect in 7 of

Nocturnal enuresis (NE) is not uncommon in children. Some children wet their beds every night and have never been dry up to their first years at school or even their teenage years. This often causes severe psychological and social strains on the affected children and their families. Children over the age of 4–6 years who wet their beds more than two nights per month are diagnosed as having NE. Several studies have reported prevalences of 5% in 10-year-olds and 10% in 6-year-olds.1 Medical treatments include wetness alarms, biofeedback, arousal treatment, fluid restriction, medication with antidiuretic hormone substitutes, and desEmployee practitioner, Stenungsund, Sweden. Professor, The Institute for Postgraduate Dental Education, Department of Orthodontics, Jo¨nko¨ping, Sweden. Corresponding author: Dr. Ulrike Schu¨tz-Fransson, Specialisttandva˚rden Ortodonti, Folktandva˚rden, Strandva¨gen 17 Stenungsund, Bohusla¨n SE-44431 Sweden (e-mail: [email protected]) a b

Accepted: April 2007. Submitted: February 2007.  2007 by The EH Angle Education and Research Foundation, Inc. DOI: 10.2319/021407-71.1

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202 Table 1. Results from pretreatment interviews and medical records for the 23 children with enuresis Individuals Sex Age Health

C.W. M 8.8

Previous treatment at ENT department Otitis more than 5 times Restless sleep Night sweating Nightmares Snoring Sleep apnea Sleeping with open mouth Sleeping in the day Tired in the morning Poor school performance Mouth breathing Parents divorced Family history of enuresis Type of enuresisa Prevalenceb a b

X X

X

P.J. P.H. F M 9.1 10.3 Allergy Asthma Adenoectomy (at 5 years old) X X X X X X

P.R. M 13.3

J.K. M 8.6 Allergy Asthma

N.J. M 15.0 Asthma

Otitis

X X X

X X X

C.G. F 13.0

A.B. F 14.1

L.S. M 11.9

JCA

Otitis X

X X X

X

V.S. M 7.9 Allergy Cleft palate

X

X

X X X

X

X X X

X

X

X

X X X

X

X X

X

X

X

X X X P 7

X X X P 7

X X P 7

P 7

X P 7

X X

X X P 3 to 4

X P 7

X P 7

P 1 to 2

X P 7

P indicates primary; S, secondary. Number of wet nights per week.

10 young children with NE who are resistant to medical therapy.11 However, a similar RME study12 of eight children under possibly stressful, psychosocial conditions at a government orphanage reported 74% improvement 8 months after RME. No subjects became completely dry. Thus, the long-term success rate is still unclear.12 These three pilot studies10–12 indicate that RME may have a positive effect on NE. Analysis of the outcome of orthodontic RME treatment in a larger group of therapy-resistant children with enuresis who were referred from pediatric specialists was therefore deemed important. The aim of this study was to assess the effect of a short period of orthodontic RME treatment on NE in children with long-standing resistance to medical therapy. The long-term success rate 10 years after RME, attitudes to treatment, and factors that influenced the success or failure were also important to analyze. MATERIALS AND METHODS Twenty-three subjects, 18 boys and 5 girls aged 6.7–15.0 years (mean ⫽ 10.1 years), took part in the study. The children and adolescents had been referred from pediatric specialists at Ryhov County Hospital in Jo¨nko¨ping, Sweden, or from other pediatric specialist clinics and had undergone a full pediatric and urologic examination. All were judged to be otherwise medically healthy. Assessment of ENT disorders was made by an ENT specialist at the hospital, and no respiratory problems were found. Angle Orthodontist, Vol 78, No 2, 2008

All children had primary enuresis, that is, enuresis had been ongoing without interruption since early childhood. Of the 23 children, 19 wet the bed every night, sometimes several times a night, and 4 children wet the bed several nights a week (Table 1). Two children were daywetting. Previous enuresis treatment included wetness alarm; behavioral therapy; Minirin (Ferring AB, Sweden), an antidiuretic hormone substitute; and acupuncture or paramedical methods. All children had earlier treatment with a wetness alarm and all except one had been treated with Minirin. All treatments had failed. Medical records were consulted, and anamneses were taken before treatment (Table 1). Pre- and postexpansion casts were taken for occlusal classification and transverse arch measurements. Eleven children had a Class I occlusion, 11 had a Class II division 1, and 1 had a Class III occlusion. Seven children had crossbites—six were unilateral and one was bilateral. Lateral head films were also taken before treatment for cephalometric diagnosis (Table 2) and measurements of posterior airway related to age.13 Thirteen children were judged to be mouth breathers at the examination. Before treatment at the ENT department, all subjects underwent anterior rhinomanometry with and without a decongestant spray to determine nasal airway resistance (Rhinocomp, Cintec Invest AB, Sweden). Posttreatment (maximum of 1 month after completion of maxillary expansion) rhinomanometric examinations at the ENT department were

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NOCTURNAL ENURESIS AND RME Table 1. Extended A.S. M 14.0 Allergy

M.Z. M 7.11

G.J. M 7.4 Asthma

X

X X X X

R.L. M 9.5

J.S. F 9.8

S.B. M 9.10

O.P. M 9.5

X

X

X X

X

X X X

X X X X

X X

X

X

X

X X

X

X

P 7

P 7

X P 7

difficult to schedule, and some patients had little interest in repeating the exam. Therefore, only 13 of the 23 patients underwent a follow-up rhinomanometric examination. Treatment consisted of orthodontic maxillary expansion using a Hyrax screw soldered to Ormco bands on the permanent first molars and first premolars of patients with these teeth (Figure 1), and on the first or second primary molars of patients who had unerupted first premolars. A parent activated the Hyrax screw each morning and evening, which gave an expansion of 0.45 mm a day. Expansion was made for a period of 2–2.5 weeks. The appliance was then replaced with a transpalatal arch in combination with a lingual arch made in contact with all teeth. This appliance was used as the retainer for 6 months. After that, the retainer was removed, the children were clinically monitored for 1 year, and the number of wet nights was recorded. A 10-year follow-up was done by administering a

X P 7

P 7

V.L. M 10.8

X X

X X

Otitis X X

X

X

X

X

X

X

X

P 7

N.I. M 6.7

X X X

X

X X P 7

J.N. F 7.0

X X X

X X P 7

A.C. M 8.10

Otitis

X X X X

X X X

P.A. M 11.10

Adenoectomy (at 1.5 years old)

Otitis X

T.T. M 9.4

X P 3

X X X X P 1 to 2

X P 7

X

X

X P 7

P 7

telephone questionnaire (Table 3). Some of the questions were suggested by pediatric specialists. The interviews were conducted by one of the authors (USF). RESULTS Of the 23 therapy-resistant children with primary NE, 11 improved and 12 reported no change after 10–14 days of orthodontic maxillary expansion (Figure 2). Six became completely dry within 1 month after expansion and another five reported notable improvement. Improvement occurred more often in subjects younger than 10 years. Of the 14 subjects younger than age 10, 5 became completely dry, 3 improved, and 6 were unaffected. Of the nine subjects aged 10 years and older, only one became completely dry (Figure 2). The children with NE who showed improvement were investigated further to determine whether improvement was correlated with age, improved nasal resistance, sagittal and transversal occlusion, or an-

Table 2. Results of the pretreatment clinical and lateral head film examination of the 23 children with enuresis Individuals C.W. P.J. P.H. P.R. J.K. N.J. V.S. C.G. A.B. L.S. A.S. M.Z. G.J. T.T. P.A. R.L. J.S. S.B. O.P. A.C. J.N. N.I. V.L. Mouth breathing X X X X X X X X X X X X Angle classification II:1 I II:1 I I I II:1 I II:1 I I I II:1 I II:1 I II:1 II:1 II:1 II.1 II:1 III I Crossbitea Cephalometric diagnosis: Retrognathic mandible Skeletal open bite a

X

X

X

XX

X X

X

X

X

X

X X

X indicates unilateral; XX, bilateral. Angle Orthodontist, Vol 78, No 2, 2008

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Figure 2. Changes in nocturnal enuresis in 23 children. Figure 1. Maxillary expansion appliance using a Hyrax screw soldered to bands on the permanent first molars and first premolars.

Rhinomanometry

amnestic factors, such as family history or school performance (Table 1). No associations were found. Before the RME, one child in the dry group, one in the improved group, and two in the no change group were wetting the bed several nights a week. After the RME, NE decreased in the improved group so that three of the five children wet their bed only 1 or 2 nights a week.

Pharyngeal airways were assessed by the ENT department at the hospital, and no major deviations were found. Nasal resistance was reduced after expansion in 8 of the 13 measured subjects, 6 of whom were younger than 9 years. The mean improvement in nasal breathing was 28%. Of the 13 clinically diagnosed mouthbreathers, 2 became dry, 5 improved, and 6 showed no change.

Expansion

10-year posttreatment interview

A mean expansion of 6.5 mm (range ⫽ 5–8 mm) was achieved. Seven children had a lateral crossbite at the start—six unilateral and one bilateral. The same amount of expansion was made for all children, irrespective of the presence of a crossbite or not. When expansion was complete, most children tended to have a scissors-bite in lateral segments. One year after the retainer was removed, transverse molar relations were normal in all children. Of the seven children with crossbites at the start, three became dry, one improved and three showed no change.

The dropout rate for the interviews 10 years after treatment was low (9%), as all but two subjects could be reached. The results of the 21 interviews were analyzed by group, that is, dry (n ⫽ 6), improved (n ⫽ 5), and no change (n ⫽ 10) during the 1-year observation period. Four members of the dry group believed RME had helped cure the enuresis, one subject said RME did not help, and one could not remember. Concerning their memories of the orthodontic appliance—whether RME was uncomfortable—five of the six subjects reported no problems and only one mentioned pain in the mouth and headache during expansion. No one was kept awake at night because of the appliance, and no one had to wake up at night to go to the bathroom. Questions on their present symptoms revealed that just one subject had to get up to urinate at night. No one had daytime symptoms, experienced obstipation, or was under medication for enuresis. Two of the six subjects in the dry group snored at night. Of the subjects that showed improvement after RME, two believed RME had helped, one thought RME had not helped, and two could not remember. One of the five subjects in this group thought the appliance was uncomfortable and made eating difficult. Four had no problems with the appliance. The appliance kept one of the subjects awake at night and one

Table 3. Posttreatment interviews: 10-year follow-up with a telephone questionnaire Past Did rapid maxillary expansion help? Was rapid maxillary expansion uncomfortable? Did you experience a relapse of enuresis? Did you wake up at night and need to urinate? Were you awake at night because of the appliance? Present Do you need to go to the bathroom at night? Since when have you been dry? Number of enuretic nights per month? Daytime symptoms (leaking,  to urinate) Obstipation? Do you snore? Are you presently on any medication for enuresis?

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subject woke up at night to go to the bathroom. Concerning present symptoms, two had to urinate at night; no one had daytime symptoms or obstipation or was on medication. Two members of this group snored at night. In the group that experienced no change in enuresis after RME, two thought RME improved the enuresis, six thought RME had not helped, and two could not remember. In this group, four had bad memories of the orthodontic appliance. They thought the appliance was large and clumsy, and they felt pain when the screws were tightened. The appliance kept one subject awake at night; two did not wake up, and seven could not remember. One had to wake up at night to go to the bathroom, three did not, and six could not remember. When this group was asked about current symptoms, four reported that they had to get up to urinate at night, nobody had any daytime symptoms or obstipation, and no one was on medication for enuresis. Two subjects reported that they snored. Ten years after the end of orthodontic treatment, 4 of the 21 interviewed subjects remembered that they were completely dry immediately after expansion. Fourteen became dry 1–3 years after RME. Three could not remember when they stopped wetting the bed. Seven still had to get up to urinate at night, no one had daytime problems or obstipation problems, and no one was on medication for enuresis. Six subjects reported that they snored. The enuresis stopped 1–3 years after RME in five subjects under the age of 10 years and nine subjects over the age of 10 years. DISCUSSION The results of RME treatment of 23 children in this study were similar to results of RME treatment of 10 children with NE in a previous pilot study.11 The results for these 33 children can be pooled for many reasons. The referrals came from the same pediatric clinics, and they were all treated at the same orthodontic clinic by the same team with identical appliances and routines for medical and dental registrations and followups. Following are the pooled results for the 33 children with NE: 10 became completely dry within 1 month of RME, 8 showed notable improvement, and 15 experienced no change. More than 50% of the pooled group experienced immediate improvement (Figure 3) compared with a spontaneous cure rate of 15% per year.1 One hypothesis of the RME treatment effect11 may be that better breathing positively affects children with NE, who have high arousal thresholds. Deficient warming and moistening of inhaled air as a result of mouth breathing might impair oxygen saturation. Also, the sleep of children with NE, although polysomno-

graphically quite normal, is exceedingly ‘‘deep,’’ that is, children with NE have high arousal thresholds. The high arousal threshold may be one of three major pathogenetic factors in enuresis; nocturnal polyuria and destrusor hyperactivity are the other two.14 Still, despite a notable increase in airflow, as measured by rhinomanometry before and after maxillary expansion, 45% of the subjects in our study were unaffected by RME. Thus, no absolute relationship seems to exist between airflow and enuresis. Cause of success The mechanism behind the success of orthodontic maxillary expansion on NE is not clearly understood. It is tempting to speculate that widening the upper dental arch and nasal structures improves airflow more than the rhinomanometric measurements indicate.11,15,16 Positive effects of improved breathing may include better moistening of air, higher oxygen saturation, and shorter periods of deep sleep so that children awaken more easily when the bladder is full. For example, it has been suggested that the ventilatory response to CO2 rebreathing in children with obstructive sleep apnea (OSA) is diminished compared with controls.17 But not all children responded. It is also possible that the placement of an irritating orthodontic appliance, whether or not it is activated, may change the awakening mechanism so that the children more easily awake when they have a full bladder. No simple explanation of the positive effects of expansion can be suggested. Enuresis plus OSA Children with OSA symptoms often have NE. Several studies have shown that NE is markedly improved or resolved after an adenoidectomy or a tonsillectomy.3,6–9 It is also interesting to note that enuresis may start at young school ages with mechanical obstruction

Figure 3. Changes in nocturnal enuresis in 33 children. Angle Orthodontist, Vol 78, No 2, 2008

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206 of the airways.3,7 A careful evaluation of the anatomy and function of the upper airway, including rhinomanometric measurements before and after orthodontic maxillary expansion with the same methods used previously, was therefore deemed necessary in this prospective study.11 However, no significant correlation between cessation of enuresis and improvement in nasal airflow, that is, nasal resistance could be found. Still, we believe the connection between enuresis and airway function is worth studying more closely in the future, perhaps studying parameters such as blood oxygen saturation and sleep quality. Breathing Although it has recently been argued that standard orthodontic radiographic methods suffice to evaluate breathing disorders,12,18 rhinomanometry with and without nasal decongestant spray both before and after maxillary expansion must be considered more accurate, especially for comparing measurements.11 We noted that the children with NE in our study had no ENT disorders and that respiratory functions were normal from the start. It could be speculated that RME relapses in the dental arch when the teeth tip due to masticatory function and cheek pressure. Osteoid formation and deposition in the median palatal suture might be more stable. It has been suggested that 9–12 months after RME, nasal airflow (nasal resistance) is still 80%–90% of the maximal expansion effect.19 Age All children had primary enuresis and were considered therapy resistant by pediatric specialists; the children wet their bed almost every night. It was notable that in the subjects younger than 10 years, eight improved and six were unaffected. In subjects aged 10 years and older, only one became completely dry and nine were less improved (Figure 2). It may be that enuresis becomes more established with time and that therapy is less effective in older persons. However, different authors have reported the same spontaneous cure rate of about 15% per year for age groups 5–9, 10–14, and 15–19 years.2 It should also be noted that in a previous study,11 the expansion effect involving reduction of nasal resistance was up to 60% greater in the younger children than in the older ones. Early RME has also been reported to be more efficient in those aged 7–8 years than in those aged 13–14 years.16 Thus, present results seem to indicate that age 10 is a breakpoint for success regarding RME treatment and cure of NE. Angle Orthodontist, Vol 78, No 2, 2008

Crossbites In this study, 7 of 23 subjects had crossbites—six unilateral and one bilateral. Mean maxillary expansion was 6.5 mm (range ⫽ 5–8 mm). This exceeded the mean of 4.1 mm (range ⫽ 3–5) in the previous study.11 The subjects with no crossbite were thus dentally overexpanded in the maxilla, but they relapsed to normal after the expansion appliance was removed. Thus, expansion treatment was performed to improve or cure enuresis, even though transverse occlusions were often normal. Two RME studies have reported clinically stable, lasting effects in the arch.20,21 It may be assumed that these studies were made in cases with indications for maxillary expansion, that is, constricted or narrow arches or transverse crossbite occlusions. It is important to note that most subjects (16 of 23) in this study had normal arch perimeters and normal transverse occlusions. Thus, a full relapse to normal transverse occlusion was not unexpected afterward. Normal transverse occlusion does not seem to be a contraindication for 5–8-mm transverse maxillary expansion in an attempt to cure NE in children. Genetics It has been reported that when both parents had a history of NE, 77% of the children had enuresis.22 In Rushton’s22 sample, only 15% of children with enuresis had no family history of the condition. Although one might think that children with a family history would be more difficult to treat, the present study did not support this. In fact, 60% of the patients in our sample (16 of 23) had a family history of enuresis (Table 1)—12 of 23 were first-degree relatives—but no correlation with successful treatment was found. Long-term effects No deviation in upper respiratory anatomy or functioning was found in any of the children. Therefore, there were no indications for an adenoidectomy or tonsillectomy. We believe the first choice of treatment in cases of enuresis is an examination of urinary function and medication. The next choice of treatment would be an evaluation of indications for an adenoidectomy or tonsillectomy. The third choice of treatment is orthodontic expansion. Although the success rate is about 50%, it is worth trying and a great relief for those who respond to treatment. Furthermore, the 10-year longitudinal follow-up found that the results of orthodontic treatment were stable: no relapses of enuresis occurred, and the patients experienced no major discomfort during orthodontic treatment. It is interesting to note that the symp-

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toms present were just as common in all three groups: dry, improved, and no change (Table 3). One third of the subjects reported that they had to urinate at night. The long-term effect of RME has been questioned, and reports in the literature are sparse.12 A questionnaire administered 4 years after RME revealed that the positive effect of RME on NE was stable. All reports on long-term effect should involve at least a 1-year follow-up as relapse is possible.11 Cause of enuresis

that airway volume improved a mean of 28%, but no significant correlation was found between airway flow and cure of NE. • The interviews revealed that the cure of NE was stable. Six of the 21 subjects believed the orthodontic appliance had been uncomfortable and painful. Questions about present symptoms revealed no major problems. Thus, orthodontic RME treatment may favorably affect primary NE in therapy-resistant children with no side effects and stable, long-term results.

Enuresis has been reported to be associated with stressful events or psychosocial disorders related to the family or school situations. Some of the questions in Table 1, such as were the parents divorced and whether school performance was poor, concerned these areas, but no such associations were found in this study. Also, modern research does not support a connection between upbringing, school, or the family situation and enuresis.1,2

Desmopressin administration has been banned/prohibited from May 2007, in the form of nasal spray due to increased risk of adverse effects, i.e. hyponatraemia, convulsions, hydrointoxication in all EU countries (ref. Pharmocovigilance working party assessment report: Desmopressin-Hyponatraemia and convulsions, 18 July 2006). This risk of side effects from medication we think will increase the interest for alternative treatment methods.

Success rate

ACKNOWLEDGMENTS

The success rate in this study of 23 children, where success was defined as dry or improved NE, was 48%, that is, somewhat less than in the pilot study by the same group (7 of 10). If the two samples are compiled, the success rate is 55% for the group of 33 children with NE after RME. Noteworthy is the fact that the 10-year follow-up found the effects to be stable. This can be compared with an annual improvement of about 15%.1 In our opinion, RME treatment can be recommended, and the success rate is encouraging, especially considering that the children in our sample were long-standing chronic cases, were therapy resistant, and had no urogenital defects or respiratory disorders. Orthodontic expansion treatment is noninvasive, routine and rather quick and it has no negative side effects or complications. A strong relationship between NE and OSA, where 35% of a group of children with OSA also had NE, has been reported.9 When surgery was indicated in children with OSA, the NE resolved 60%–75% of the time.9

We are grateful for the referrals from the pediatric specialists at Ryhov County Hospital and pediatric clinics in Jo¨nko¨ping County. We especially thank Anders Bjerkhoel, MD, for assistance with the ENT examination and rhinomanometry.

CONCLUSIONS • RME seems to positively affect NE. Results of orthodontic RME treatment in 23 children (aged 6–15 years old) with long-standing therapy-resistant primary enuresis were fairly immediate improvement in almost 50%. This is in comparison with an estimated spontaneous improvement of 15% per year. Children below the age of 10 years responded better. Rhinomanometry before and after expansion revealed

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