Amniotic band syndrome and limb body wall complex in Europe 1980-2019.

Amniotic band syndrome (ABS) and limb body wall complex (LBWC) have an overlapping phenotype of multiple congenital anomalies and their etiology is unknown. We aimed to determine the prevalence of ABS and LBWC in Europe from 1980 to 2019 and to describe the spectrum of congenital anomalies. In addition, we investigated maternal age and multiple birth as possible risk factors for the occurrence of ABS and LBWC. We used data from the European surveillance of congenital anomalies (EUROCAT) network including data from 30 registries over 1980-2019. We included all pregnancy outcomes, including live births, stillbirths, and terminations of pregnancy for fetal anomalies. ABS and LBWC cases were extracted from the central EUROCAT database using coding information responses from the registries. In total, 866 ABS cases and 451 LBWC cases were included in this study. The mean prevalence was 0.53/10,000 births for ABS and 0.34/10,000 births for LBWC during the 40 years. Prevalence of both ABS and LBWC was lower in the 1980s and higher in the United Kingdom. Limb anomalies and neural tube defects were commonly seen in ABS, whereas in LBWC abdominal and thoracic wall defects and limb anomalies were most prevalent. Twinning was confirmed as a risk factor for both ABS and LBWC. This study includes the largest cohort of ABS and LBWC cases ever reported over a large time period using standardized EUROCAT data. Prevalence, clinical characteristics, and the phenotypic spectrum are described, and twinning is confirmed as a risk factor.

Amniotic band syndrome with CNS involvement: a pediatric neurosurgeon's dilemma-a case series and literature review.

BACKGROUND: Amniotic band syndrome (ABS) is a rare congenital disease characterized by a broad spectrum of congenital anomalies resulting from the strangulated developing organ(s) by the detached fibrous amniotic band. The prevalence of CNS involvement in ABS is rare, but the mortality rate in these cases is high, while morbidity among the surviving patients is inevitable. CASE REPORT: Three-month-old male, 9-month-old female, and newborn female babies were presented with head lump(s), severe facial cleft, syndactyly, and finger amputation. The patient's head imaging confirmed meningoencephalocele as the cause of the head lump in 2 patients; meanwhile, a porencephalic cyst was identified as the origin of head lumps in the other patient. VP shunt placement surgery was performed as the initial management in 2 patients, while one patient directly underwent meningoencephalocele resection surgery. Craniofacial and limb reconstructions were planned as the follow-up management in all cases. Unfortunately, one patient died of complications from suspected aspiration, while another never returned for follow-up treatment. CONCLUSION: Here, we report 3 ABS cases with CNS involvement. Despite the severe disfigurement and disability, the inexistence of fatal malformation might lead to long-term survival. The treatment of malformation(s) that might predispose to another fatal condition and surgery(-ies) to improve functional outcomes and patient's social acceptability should be prioritized in managing the surviving ABS patients.

Severe Eyelid Malformation With Facial Clefting and Amniotic Bands.

Amniotic bands can lead to eyelid colobomas contiguous with facial clefts, resulting in severe and highly variable eyelid malformations. There is no known underlying genetic cause of amniotic band sequence. Here, the authors review the case of an infant born with large, 4-eyelid colobomatous defects in the setting of facial clefts, amniotic bands and an underlying SMOC1 mutation, which has not previously been linked to amniotic band sequence or eyelid colobomas. Reconstructive technique and the postoperative course are described, and underlying etiologic theories of amniotic band sequence are reviewed and expanded upon. Although amblyopia prevention in this patient with poor visual potential was not a consideration, the goals of improving the patient's ocular surface and maintaining eye contact were achieved.

A new phenotype of amniotic band syndrome with occipital encephalocele-like morphology: a case report.

Amniotic band syndrome (ABS) is a congenital abnormality that can cause a variety of deformities. Here, we report a case of ABS in which the amniotic band adhered to the skull, causing a partial cranial defect that was difficult to differentiate from an occipital encephalocele. The mother was a 24-year-old with an unremarkable medical and family history. Ultrasonography performed at 16 weeks showed that the fetus had a membranous structure in the occipital region. Occipital encephalocele was suspected, and she underwent cesarean section at 38 weeks. A male newborn was delivered, and his left occipital skin had a defect measuring 2 cm, from which a cystic structure had prolapsed. Cranial magnetic resonance imaging showed that the cystic structure had homogeneous high signal intensity on T2-weighted images. The neonate then underwent repair of the occipital encephalocele. During the operation, the membranous structures and dura were not continuous. Histological examination revealed that the membranous structures were composed of amnion, suggesting that this was a case of ABS. ABS may present with an encephalocele-like morphology without affecting the brain tissue and meninges. If an atypical encephalocele is found after birth, examination of the placenta may be helpful for a definitive diagnosis.

Disseminated intravascular coagulation complicated by amniotic band syndrome associated with deceased fetal umbilical cord following fetoscopic laser surgery.

Fetoscopic laser surgery occasionally causes amniotic band syndrome, in which the disrupted amniotic membrane constricts fetal body parts, leading to functional or morphological loss. We report a case of fetal distress at 31 weeks of gestation in the larger surviving twin after fetoscopic laser surgery for selective intrauterine growth restriction, necessitating emergent cesarean section. Physical examination of the infant showed constriction rings caused by a disrupted amniotic membrane on the digits, and the distal part of the right index finger was necrotic because of tight strangulation by an amniotic band with the umbilical cord of the deceased smaller twin. Laboratory data showed severe coagulopathy, and the infant was diagnosed with disseminated intravascular coagulation (DIC). Immediate treatment improved his condition. DIC may have been associated with the necrotic finger, which was strangulated by the umbilical cord of the deceased fetus, because neither maternal coagulopathy nor an underlying neonatal disorder was detected.

Media Depiction of Birth Differences of the Upper Extremity: Accuracy of Shared Diagnoses.

BACKGROUND: To assess the diagnostic accuracy of public representation of congenital differences of the upper extremities. We hypothesized that there is an over-diagnosis of certain diagnoses such as amniotic constriction band and under-diagnosis of others such as symbrachydactyly and radial deficiency. METHODS: Publicly shared images and associated diagnoses were searched on publicly available news media and social media accounts published from October 2018 through November 2021 using key terms such as "amniotic band syndrome," "congenital arm amputation," and "3D prosthetic arm" as well as The Lucky Fin Project account on Instagram. The images were collected and reviewed by 2 congenital hand surgeons. The surgeons' diagnoses were then compared to the reported diagnoses associated with each image to assess accuracy. RESULTS: A total of 100 images were collected with the reported diagnosis associated with each image. Two images were removed due to evidence of prior surgery. The hand surgeons' diagnosis disagreed with the reported diagnosis in 60 of 98 (61%) images. Of those 60 inaccurate diagnoses, 2/3 were reported as amniotic constriction band. CONCLUSIONS: Media and social media depictions of congenital upper extremity differences are frequently inaccurate, and our search demonstrated that the amniotic constriction band is the most commonly reported, inaccurate diagnosis. Accuracy of diagnosis in public media is important given the impact a diagnosis has on those viewing and sharing the images. LEVEL OF EVIDENCE: Level IV, diagnostic.

Amniotic band syndrome in a monochorionic diamniotic twin pregnancy after rupture of the dividing membrane in the early second trimester: A case report.

BACKGROUND: Amniotic band syndrome is a rare phenomenon, but it can result in serious complications. We report herein our experience of amniotic band syndrome in a monochorionic diamniotic twin pregnancy where rupture of the dividing membrane occurred early in the second trimester. CASE PRESENTATION: A 29-year-old nulliparous woman was referred to us for management of her monochorionic diamniotic twin pregnancy at 10 weeks of gestation. When we were unable to identify a dividing membrane at 15 weeks of gestation using two-dimensional ultrasonography, we used three-dimensional ultrasonography to confirm its absence. Both modalities showed that the left arm of baby B was swollen and attached to a membranous structure originating from the placenta at 18 weeks of gestation. Tangled umbilical cords were noted on magnetic resonance imaging at 18 weeks of gestation. Emergency cesarean delivery was performed at 30 weeks of gestation because of the nonreassuring fetal status of baby A. The left arm of baby B had a constrictive ring with a skin defect. Both neonates had an uncomplicated postnatal course and were discharged around 2 months after delivery. CONCLUSIONS: Attention should be paid to the potential for amniotic band syndrome if rupture of the dividing membrane between twins is noted during early gestation.

Sinus pericranii-unusual anatomic obstacle to posterior decompression on an amniotic band sequence.

Abnormal venous drainage in patients with craniofacial anomalies is relativity uncommon. Sinus pericranii is a rare vascular malformation characterized by communication between intracranial dural sinuses and extracranial venous drainage systems. The association between sinus pericranii and amniotic band syndrome has not been described. We report on a 7-month-old girl diagnosed with amniotic band sequence who underwent posterior fossa decompression due to intracranial hypertension and Chiari malformation type I. The computed tomography and magnetic resonance identified the connection between the sagittal sinus and the scalp. During the operation, the presence of sinus pericranii was a complicating factor limiting the proper exposure because of the risk of bleeding. Patients with craniofacial anomalies and sinus pericranii present an increased risk of serious surgical complications and consequences from craniofacial surgery, especially from cranioplasty and posterior decompression. Special attention must be paid to abnormal venous drainage, and vascular imaging studies are sometimes required.

Amniotic band syndrome associated with limited dorsal myeloschisis: a case report of an unusual case and review of the literature.

Amniotic band syndrome (ABS) has been known since ancient times. Descriptions in modern medicine have occurred since the mid-nineteenth century. The association of the amniotic band syndrome with tethered cord is rare. It was generally thought to be incompatible with life. Of late, with better imaging, there have been case reports of amniotic bands causing cord tethering in neurosurgical literature, but its association with limited dorsal myeloschisis has hitherto not been described. We report a case of amniotic band syndrome (ABS) associated with a cervical limited dorsal myeloschisis (LDM) in a child of 2 and a half years old. The management of LDM in ABS is essentially the same as in isolated cases.

The Ponseti Method for the Treatment of Clubfeet Associated With Amniotic Band Syndrome: A Single Institution 20-Year Experience.

BACKGROUND: Amniotic band syndrome (ABS) is a congenital disorder resulting in fibrous bands that can cause limb anomalies, amputations, and deformities. Clubfoot has been reported in up to 50% of patients with ABS. The purpose of this study is to compare treatment characteristics and outcomes of clubfoot patients with ABS to those with idiopathic clubfoot treated with the Ponseti method. METHODS: An Institution Review Board (IRB) approved retrospective review of prospectively gathered data was performed at a single pediatric hospital over a 20-year period. Patients with either idiopathic clubfeet or clubfeet associated with concomitant ABS who were <1 year of age and treated by the Ponseti method were included. Initial Dimeglio score, number of casts, need for heel cord tenotomy, recurrence, and need for further surgery were recorded. Outcomes were classified as "good" (plantigrade foot±heel cord tenotomy), "fair" (need for a limited procedure), or "poor" (need for a full posteromedial release). RESULTS: Forty-three clubfeet in 32 patients with ABS, and 320 idiopathic clubfeet in 215 patients were identified. Average age at last follow up was not different between ABS and idiopathic cohorts (7.4 vs. 5.2 y, P=0.233). Average Dimeglio score was lower in the ABS cohort (12.3 vs. 13.7, P=0.006). Recurrence rate was significantly higher in the ABS (62.8%) compared with idiopathic cohort (37.2%) (P=0.001). Clinical outcomes were significantly better in the idiopathic cohort (69.4% "good", 26.9% "fair", 3.8% "poor") compared with the ABS cohort (41.9% "good", 34.9% "fair", and 23.3% "poor") (P<0.001). Within the ABS cohort, no significant differences in clinical outcomes were found based upon location, severity, or presence of an ipsilateral lower extremity band. CONCLUSION: Clubfeet associated with ABS have higher rates of recurrence, a greater need for later surgery, and worse clinical outcomes than idiopathic clubfeet. This information may prove helpful in counseling parents of infants with ABS associated clubfeet. LEVEL OF EVIDENCE: Level III.

Risk Factors and Prevalence of Limb Deficiencies Associated With Amniotic Band Sequence: A Population-based Case-control Study.

BACKGROUND: Limb deficiencies associated with amniotic bands comprise a wide range of congenital anomalies. The association of maternal medication and the risk of amniotic band sequence (ABS) has not yet been addressed. METHODS: This nationwide population-based case-control study used national registers on congenital anomalies, births and induced abortions, cross-linked with information on maternal prescription medicine use obtained from the registers on Reimbursed Drug Purchases and Medical Special Reimbursements. All cases with congenital limb deficiency associated with amniotic bands born between 1996 and 2008 were included in the study. Five controls without limb deficiency matched for residency and time of conception were randomly selected from the Medical Birth Register. RESULTS: In total, 106 children with limb deficiency associated with ABS were identified and compared with 530 matched controls. Young maternal age (less than 25 y) increased the risk of limb deficiencies [odds ratio=1.72; 95% confidence interval (CI): 1.06, 2.80]. Primiparity was also associated with increased risk [adjusted odds ratio (aOR)=2.42; 95% CI: 1.52, 3.88]. After adjusting for maternal age, pregestational diabetes, and parity, maternal use of beta-blockers (adjusted OR=24.2; 95% CI: 2.57, 228) and progestogens (adjusted OR=3.79; 95% CI: 1.38, 10.4) during the first trimester of pregnancy significantly increased the risk of limb deficiencies associated with amniotic bands. CONCLUSIONS: Primiparity significantly increased the risk of limb defects associated with amniotic bands. Also, a novel association on increased risk of ABS with maternal use of progestogens or beta-blockers during the first trimester of pregnancy was observed. LEVEL OF EVIDENCE: Level III.

Amniotic band sequence in paternal half-siblings with vascular Ehlers-Danlos syndrome.

Familial amniotic band sequence (ABS) is rare but has been reported in the offspring of mothers with connective tissue disorders. We present a family of two half-siblings with ABS who share the same biological father. Following a serious vascular event a de novo pathogenic variant in COL3A1 was detected in the father, confirming a diagnosis of vascular Ehlers-Danlos syndrome (vEDS). The same variant was found in both his ABS-affected children but not in his unaffected child. The amniotic membrane is derived from fetal tissue, type III collagen being a component. As the affected children are paternal half-siblings, ABS was less likely due to maternal factors. Rather, the amniotic bands may have resulted from decreased type III collagen production as seen in people with vEDS, causing fragility of the amniotic membrane. Consequently, it is important to consider vEDS in patients with ABS.

Prevalence, risk factors, and outcome of postprocedural amniotic band disruption sequence after fetoscopic laser surgery in twin-twin transfusion syndrome: a large single-center case series.

BACKGROUND: Postprocedural amniotic band disruption sequence is a condition that is associated with intrauterine interventions, and it is characterized by a constriction of the limbs or umbilical cord by fibrous strands, leading to edema, amputation, and/or fetal demise. OBJECTIVE: To evaluate the prevalence of, risk factors for, and the outcome of postprocedural amniotic band disruption sequence after fetoscopic laser surgery in twin-twin transfusion syndrome cases. STUDY DESIGN: All consecutive cases of twin-twin transfusion syndrome treated with fetoscopic laser coagulation of the vascular anastomoses at our center between January 2002 and March 2019 were included in the study. The occurrence of postprocedural amniotic band disruption sequence in these cases was recorded, and the potential risk factors were analyzed. RESULTS: Postprocedural amniotic band disruption sequence was detected, at birth, in 2.2% (15/672) of twin-twin transfusion syndrome cases treated with fetoscopic laser surgery, in both the recipients (10/15, 67%) and the donors (5/15, 33%). Postprocedural amniotic band disruption sequence primarily affected the lower extremities (11/15, 73%) and, less frequently, the upper extremities (2/15, 13%), both the upper and lower extremities (1/15, 7%), or the umbilical cord (1/15, 7%). Postprocedural amniotic band disruption sequence led to the amputation of toes in 5 of 15 cases (33%) and resulted in fetal demise because of constriction of the umbilical cord in 1 case (7%). The independent risk factors identified for postprocedural amniotic band disruption sequence were lower gestational age at laser surgery (odds ratio per week, 1.43; 95% confidence interval, 1.12-1.79; P=.003) and the presence of postprocedural chorioamniotic membrane separation on antenatal ultrasound examination (odds ratio, 41.66; 95% confidence interval, 5.44-319.25; P<.001). CONCLUSION: The prevalence of postprocedural amniotic band disruption sequence is low, but, when present, it may lead to severe consequences, with amputation of extremities or fetal demise occurring in more than one-third of the cases. Lower gestational age at the time of laser therapy and chorioamniotic membrane separation are independent risk factors for the postprocedural amniotic band disruption sequence.

[The amniotic band syndrome : a rare and severe malformative pathology]. / La maladie des brides amniotiques. Une pathologie malformative rare et sévère.

Antenatal diagnosis of the amniotic band syndrome often occurs during the second trimester of pregnancy when complex and asymmetrical limb deformities are observed. As vital prognosis depends on the gravity of malformations, lesion assessment should be as accurate as possible. Color doppler US screening is useful and could unravel limb vascular compression by an amniotic band. A vascular stop predicts in utero limb amputation. We hereby report the case of a 30-year-old patient pregnant with a fœtus presenting 4-limb deformities. One limb was highly suspected of undergoing amputation. Facing those heavy-burden anomalies, the patient asked for a medical termination of her pregnancy.

Le diagnostic anténatal de la maladie des brides amniotiques est le plus souvent réalisé au deuxième trimestre de la grossesse par la mise en évidence de malformations complexes et asymétriques des membres. Comme le pronostic dépend de la gravité des malformations, un bilan lésionnel précis doit être réalisé. L'utilisation du doppler couleur permet d'évaluer la compression vasculaire par la bride au niveau des membres. L'arrêt du flux artériel semble prédictif d'une amputation du membre in utero. Nous rapportons le cas d'une patiente dont le fœtus présentait des anomalies des 4 membres avec un membre en voie d'amputation et qui, devant la gravité des lésions, a souhaité une interruption médicale de grossesse.

Amniotic Band Syndrome: A Review of 2 Cases.

Amniotic band syndrome is a rare congenital disorder caused by entrapment of fetal parts (usually a limb or digits) in fibrous amniotic bands while in utero that presents with complex multisystem anomalies. The authors report 2 children with amniotic band syndrome who presented to the ophthalmic unit of the authors' pediatric hospital. One of them presented with telecanthus, syndactyly, amputated toes, and unilateral epiphora diagnosed as congenital nasolacrimal duct obstruction. She was managed conservatively with lacrimal sac massage and provided with refractive correction while she simultaneously underwent multiple surgeries for correction of clubfoot and craniosynostosis. The second patient presented with cleft lip, cleft palate, multiple constriction bands in upper limbs and fingers with unilateral microphthalmos, microcornea, typical iris coloboma, and retinochoroidal coloboma, very similar to a case reported in literature. These 2 cases provide an overview of the clinical spectrum of ophthalmic manifestations along with their staged optimum rehabilitation.

Severe Craniofacial Involvement due to Amniotic Band Sequence.

BACKGROUND: Disruptive amniotic band sequence (DABS) is a sporadic, non-familial disorder with unclear etiology. Diagnosis is based on clinical features because there is currently no reliable laboratory diagnostic tests. OBJECTIVE: We describe six cases of DABS with severe craniofacial deformations, three with and three without classical constrictive limb deformation. RESULTS: The craniofacial deformities were delimited by peripheral sharply demarcated scarring. CONCLUSION: When a sharply demarcated linear disruptive craniofacial lesion is observed, DABS should be considered despite the absence of constrictive limb scarring.

Amniotic band syndrome with pseudoarthrosis of tibia and fibula: A case report.

Constriction of the lower limb by congenital amniotic band has been proposed to explain the development of pseudoarthrosis of tibia and fibula. We report a case of amniotic band syndrome in a preterm infant with pseudoarthrosis of tibia and fibula. Simple release of constriction band with Z-plasty resulted in the growth of mature bone, replacing the pseudoarthrosis and hence did not require surgical amputation. Our case confirms the potential for bone growth in ABS, once the constricting band is released. Early limb preserving surgery with release of the constricting band with an intention to salvage the limb appears appropriate.

Congenital adhesion band causing small bowel obstruction: What's the difference in various age groups, pediatric and adult patients?

BACKGROUND: A congenital adhesion band is a rare condition, but may induce a small bowel obstruction (SBO) at any age. However, only a few sporadic case reports exit. We aimed to identify the clinical characteristics of congenital adhesion band manifesting a SBO stratified by age group between pediatric and adult patients. METHODS: The medical records of all patients with a SBO between Jan 1, 2009 and Dec 31, 2015 were retrospectively reviewed. Cases associated with previous surgical procedure and cases of secondary obstruction due to inflammatory processes or tumor and other systemic diseases were excluded. The patients were divided into two groups according to age below or above 18 years: pediatric and adult. The basic clinical characteristics were analyzed and compared between groups. RESULTS: Of 251 patients with a SBO, 15 (5.9%) met the inclusion criteria; 10 cases in pediatric group (mean age 17.9 ± 38.7 months) and 5 cases in adult group (mean age 60.0 ± 19.7 years). The pediatric group (66.6%) included 3 neonates, 5 infants, and 2 school children. They usually presented with bilious vomiting (50.0%) and abdominal distention (60.0%), and demonstrated a high rate of early operation (80.0%) and bowel resection (70.0%). In contrast, the adult group (33.3%) presented with abdominal pain (100%) in all cases and underwent a relatively simple procedure of band release using a laparoscopic approach (60%). However, group differences did not reach statistical significance. In addition, two groups did not differ in the time interval to the operation or in the range of the operation (p = 0.089 vs. p = 0.329). No significant correlation was found between the time interval to the operation and the necessity of bowel resection (p = 0.136). There was no mortality in either group. CONCLUSIONS: Congenital adhesion band is a very rare condition with diverse clinical presentations across ages. Unlike adult patients, pediatric patients showed a high proportion of early operation and bowel resection. A good result can be expected with an early diagnosis and prompt management regardless of age.

The Effectiveness of the Ponseti Method for Treating Clubfoot Associated With Amniotic Band Syndrome.

BACKGROUND: Amniotic band syndrome (ABS) is a congenital disorder with an associated incidence of clubfoot deformity in over 50% of patients. Although early reports in the literature demonstrated a poor response to casting treatments, recent application of the Ponseti technique in ABS patients have been more promising. METHODS: A retrospective review of all patients with clubfoot and a concurrent diagnosis of ABS were reviewed at a single institution. Patients not managed initially with the Ponseti method were excluded. Data collected included patient age at presentation, sex, unilateral or bilateral, amniotic band location and associated findings, and response to treatment-number of casts and requirement of Achilles tenotomy, tibialis anterior tendon transfer, or other surgical procedures. Duration of treatment at latest follow-up visit was noted and outcome was based on clinical foot appearance and plan for any further procedures. RESULTS: Twelve patients (7 female and 5 male) with a total of 21 feet (9 bilateral and 3 unilateral) were identified. The average age at presentation was 3 weeks (range, 1 to 9 wk). The average number of casts was 6 (range, 3 to 11). Seventeen of 21 feet (81.0%) underwent percutaneous Achilles tenotomy. The initial correction rate for all patients with the Ponseti technique was 20/21 feet (95.2%) and recurrence was noted in 7/21 feet (33.3%). One patient underwent primary posteromedial release and 2 patients had associated neurological deficits. The average follow-up was 3.9 years (range, 9 mo to 10 y) and all but one patient had supple, plantigrade feet. CONCLUSION: The Ponseti technique is an effective first-line treatment in patients who have clubfeet associated with ABS, including those with a neurological deficit. LEVEL OF EVIDENCE: Level IV.

Biomechanical effects of maxillary expansion on a patient with cleft palate: A finite element analysis.

INTRODUCTION: The aims of this study were to evaluate the effects of rapid palatal expansion on the craniofacial skeleton of a patient with unilateral cleft lip and palate (UCLP) and to predict the points of force application for optimal expansion using a 3-dimensional finite element model. METHODS: A 3-dimensional finite element model of the craniofacial complex with UCLP was generated from spiral computed tomographic scans with imaging software (Mimics, version 13.1; Materialise, Leuven, Belgium). This model was imported into the finite element solver (version 12.0; ANSYS, Canonsburg, Pa) to evaluate transverse expansion forces from rapid palatal expansion. Finite element analysis was performed with transverse expansion to achieve 5 mm of anterolateral expansion of the collapsed minor segment to simulate correction of the anterior crossbite in a patient with UCLP. RESULTS: High-stress concentrations were observed at the body of the sphenoid, medial to the orbit, and at the inferior area of the zygomatic process of the maxilla. The craniofacial stress distribution was asymmetric, with higher stress levels on the cleft side. When forces were applied more anteriorly on the collapsed minor segment and more posteriorly on the major segment, there was greater expansion of the anterior region of the minor segment with minimal expansion of the major segment. CONCLUSIONS: The transverse expansion forces from rapid palatal expansion are distributed to the 3 maxillary buttresses. Finite element analysis is an appropriate tool to study and predict the points of force application for better controlled expansion in patients with UCLP.