The Cleft Palate–Craniofacial Journal 53(1) pp. 118–125 January 2016 Ó Copyright 2016 American Cleft Palate–Craniofacial Association
CASE REPORT Monobloc Le Fort III Distraction Osteogenesis for Correction of Severe Fronto-orbital and Midface Hypoplasia in Pediatric Crouzon Syndrome Firdaus Hariri, M.B.B.S., B.D.S., M.D.S.(O.M.F.S.), Lim Kwong Cheung, B.D.S., F.F.D.R.C.S., Ph.D., Zainal Ariff Abdul Rahman, B.D.S., M.Sc., F.D.S.R.C.S., Vickneswaran Mathaneswaran, M.B.B.S., F.R.C.S., Dharmendra Ganesan, M.B.B.S., M.Surg., F.R.C.S. In severe syndromic craniosynostosis, distraction osteogenesis (DO) provides superior segmental advancement and allows progressive clinical monitoring to ensure that adequate skeletal expansion is achieved. We report two cases of Crouzon syndrome involving a 3-year-old boy and a 4-year-old girl, who were both treated with monobloc Le Fort III DO using a combination of external and internal distraction devices (Synthes, Oberdorf, Switzerland) to treat severe orbital proptosis and obstructed nasopharyngeal airway secondary to severe hypoplastic craniofacial skeletal components. Their skeletal segments were advanced in daily increments by 27 mm and 23 mm, respectively. Results at 18 months postoperatively showed successful outcomes, as evidenced by adequate eye protection, tracheostomy tube decannulation following objective evidence of patent nasopharyngeal airway, and acceptable facial appearance. Monobloc Le Fort III DO using a combination of external and internal devices produces favorable functional and clinical outcomes for the treatment of severe orbital and airway discrepancy in Crouzon syndrome. KEY WORDS:
craniofacial surgery, Crouzon syndrome, distraction osteogenesis, monobloc Le Fort III
Traditionally, the craniofacial deformity has been treated with conventional fronto-orbital advancement, which was introduced by Ortiz-Monasterio et al. (1978) and has proven to be a reliable surgical procedure to treat symptomatic syndromic craniosynostosis. However, in a severely hypoplastic patient, a large segmental advancement is needed, requiring the gap to be grafted and stabilized. Large advancement may require sufficient bone grafting and soft tissue for primary wound closure, of which both are limited in pediatric calvaria. The use of plates has been reported, but migration of titanium plates and the instability of resorbable plates limit their application (Dunaway et al., 2012). Inadequate stability secondary to soft tissue limitation and unstable bone segment fixation after significant advancement may cause the graft to resorb, leading to a less than ideal long-term outcome. The application of distraction osteogenesis (DO) in treating syndromic craniofacial patients began in the mid1990s and has since become widely used, with many articles reporting on the use of either external or internal devices (Polley et al., 1995; Gosain et al., 2002; Witherow et al., 2008; Meling et al., 2011; Marchac and Arnaud, 2012). A literature search found limited data on the application of a combination of external and internal distractors for advancing a monobloc Le Fort III segment in syndromic craniosynostosis (Jacobsen et al., 2009; Marchac and Arnaud, 2012; Nishimoto et al., 2012). The objective of this study is to evaluate two patients with pediatric Crouzon
Conventional monobloc Le Fort III osteotomy is an established surgical procedure to treat syndromic craniosynostosis conditions, such as Crouzon syndrome, in pediatric patients. In Crouzon syndrome, patients typically present with hypoplastic midface with orbital proptosis and additional orbital dystopia that may produce orbital hypertelorism (Posnick et al., 2004). In severe cases, patients may also present with significant upper airway obstruction, with progressive obstructive sleep apnea secondary to a severely hypoplastic maxilla, which may eventually require tracheostomy to bypass the obstructed airway.
Dr. Hariri is Senior Lecturer, Department of Oro-Maxillofacial Surgical and Medical Sciences, Faculty of Dentistry, University of Malaya, Malaysia. Dr. Cheung is Professor, Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Dr. Abdul Rahman is Professor, Department of Oro-Maxillofacial Surgical and Medical Sciences, Faculty of Dentistry, University of Malaya, Malaysia. Dr. Mathaneswaran and Dr. Ganesan are Professor, Neurosurgery Unit, Department of Surgery, Faculty of Medicine, University of Malaya, Malaysia. Grant: University of Malaya’s HIR-MOHE research grant initiative (HIR Ref No: UM.C/625/1/HIR-MOHE/12). Submitted July 2014; Revised October 2014; Accepted October 2014. Address correspondence to: Dr. Firdaus Hariri, Department of OroMaxillofacial Surgical and Medical Sciences, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia. E-mail fi[email protected]. DOI: 10.1597/14-210 118
Hariri et al., MONOBLOC DISTRACTION OSTEOGENESIS IN CROUZON SYNDROME
TABLE 1 Patient 1
Patients’ Surgical Background Prior to Monobloc Le Fort III Distraction Osteogenesis
Age, y 3
Gender Male
Diagnoses
Crouzon syndrome Severe obstructive sleep apnea
Surgical History
2
119
4
Female
Crouzon syndrome Severe obstructive sleep apnea
Bilateral tarsorrhaphy Right eye amniotic membrane transplant with tarsorrhaphy and silicone sheet attachment First fronto-orbital advancement Second fronto-orbital advancement Ventriculoperitoneal shunt insertion Right eye tarsorrhaphy repair Ventriculoperitoneal shunt revision Second ventriculoperitoneal shunt revision Third ventriculoperitoneal shunt revision Third fronto-orbital advancement and cranioplasty Tracheostomy Removal of titanium screws and plate Ventriculoperitoneal shunt First fronto-orbital advancement Second fronto-orbital advancement Endoscopic adenoidectomy Tracheostomy
syndrome treated by DO using a combination of external and internal distraction devices and to review some critical issues regarding the application of DO in craniofacial surgery. CASE REPORT We report two cases, a 3-year-old boy and a 4-year-old girl, who were both diagnosed with Crouzon syndrome. Both patients presented with severe orbital proptosis and obstructive sleep apnea secondary to a severely hypoplastic midface. Both patients had undergone multiple surgical procedures involving conventional fronto-orbital advancement to decompress the cranial cavity and salvage the function of the eyes and had undergone tracheostomy to bypass the obstructed upper airway. Patient 1 underwent tarsorrhaphy on both eyes after birth but eventually developed right eye blindness secondary to persistent corneal abrasion damage resulting from severe exorbitism. The medical histories of both patients are summarized in Table 1.
The management of pediatric craniofacial cases in our center involves a multidisciplinary team from the departments of oral and maxillofacial surgery, neurosurgery, otolaryngology, ophthalmology, clinical genetics, anesthesiology, and pediatric respiration. Clinical and imaging assessments resulted in skeletal diagnoses of a combination of severe fronto-zygomatico-naso-maxillary hypoplasia and Angle Class III malocclusion for both patients. We performed a comprehensive presurgical craniomaxillofacial protocol for both patients, which consisted of clinical evaluation, computed tomography scan, presurgical airway analysis (3dMD, Atlanta, GA), and simulation surgery using Surgicase software (Materialize, Leuven, Belgium) combined with three-dimensional (3D) biomodel simulation surgery and prebending of distractor footplates to achieve precision (Fig. 1). Both patients’ surgical plans were finalized with a goal of maximum segmental advancement to achieve adequate eye protection and open the nasopharyngeal airway. As such, a surgical procedure, monobloc Le Fort III DO, that used a combination of external and internal devices was planned to achieve the aforementioned aims for both patients.
FIGURE 1 Presurgical planning images for patient 2. A: Airway analysis. B: Surgicase software surgical simulation. C: Surgical simulation of stereomodel and adaptation of distraction devices.
None None 6
Conservative: antibiotics, close monitoring, and distraction rate reduction Surgical exploration Leakage of cerebrospinal fluid Right eye exodeviation with limited abduction 5
5 2
1.0–1.5
2–3
23
1 month after completion of distraction phase 27 2–3 1.0–1.5 5 1
Total Advancement, mm Activation Frequency, Turns/d Distraction Rate, mm/d Latency Period, d Patient
Summary of Patients’ Distraction Protocols and Complications
Removal of External Frame
Consolidation Phase, mo
Complication Associated with Distraction Procedure
Management
Cleft Palate–Craniofacial Journal, January 2016, Vol. 53 No. 1
TABLE 2
120
Both patients successfully underwent the monobloc Le Fort III DO via a combination of coronal and intraoral approaches. The surgical procedure started with a frontal bone craniotomy, followed by Le Fort III osteotomy. During the Le Fort III procedure, a slight modification was performed; the anterior limb of the medial canthal ligament at the medial orbital rims was detached from the fronto-maxillary bony process on either side, as described by Cheung et al. (1998). This exposed the lacrimal sac, which was reflected to expose the lacrimal groove. The dissection was continued inferiorly along the infraorbital rim as far laterally as possible. Separation of the nasal septum from the skull base was achieved with a septal osteotome, which was inserted through the nasal bone osteotomy cut to engage the perpendicular cribiform plate. An intraoral approach was performed to complete the pterygomaxillary dysjunction. The removed frontal bone was then fixed to the supraorbital rim of the Le Fort III segment. To ensure stability and optimum segmental advancement, we used both an external midface distractor and two internal craniomaxillofacial distractors (Synthes, Oberdorf, Switzerland). The external midface distractor consisted of two zygomatic plates with percutaneous pins, placed bilaterally at the glabella region, and another two plates in the maxilla, placed bilaterally just lateral to the piriform rim. The two internal distractors with prebent footplates were fixed according to the predetermined sites according to a presurgical stereomodel plan. Trial activation of the internal devices was performed before wound closure. The rigid external distractor frame was positioned after the wound closure. Alignment of the frame was checked to ensure its stability and determine the principal distraction vector. All surgical stages proceeded uneventfully. Two subcutaneous vacuum drains were placed, and both patients were kept in the pediatric intensive care unit for close observation for 48 hours. Both patients were given antibiotics and corticosteroids upon induction of general anesthesia and postoperatively. In terms of the distraction protocol, both patients had a latency period of 5 days. The distractors were activated two to three times a day to achieve 1.0 to 1.5 mm of movement per day. The wounds were cleaned and checked, and both patients were given analgesic syrup prior to activation. In total, six distraction points were activated in each patient; two were from the internal distractors and four were from the anchoring rods of the external distractors. All six points were activated by the same amount. The segmental advancement achieved was 27 mm in patient 1 and 23 mm in patient 2, based on the total activation amount from the protocol. The activation amount was routinely crosschecked with the length of the anchoring rods of external distractors to ensure consistency. The decision to stop activation was based on clinical assessment of eyelid closure, with slight overcorrection, and adequate nasopharyngeal opening based on an endoscopic procedure. The
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FIGURE 2 Pre- and postoperative photos of Patient 1 and Patient 2. A: Preoperative appearance. B: Activation phase. C: After 3 months of consolidation, with the external distractor removed. D: At 10 months postdistraction. E: At 18 months postdistraction.
consolidation period was 5 months for patient 1 and 6 months for patient 2. A summary of the distraction protocol is summarized in Table 2. Patient 1 was noted to have a cerebrospinal fluid (CSF) leak at 2 weeks postoperatively. The condition was treated conservatively with close monitoring, antibiotics, and reduction of the distraction rate. He also developed right eye exodeviation with limited abduction, which was noted when the advancement
FIGURE 3
reached 23 mm (Hariri et al., 2015). An urgent computed tomographic scan showed that there was an impingement of the lateral rectus muscle in the globe region from the distracted segment. A surgical procedure to relieve the impingement was performed, and eye function had returned to normal 2 weeks after the procedure. Patient 2 had an uneventful recovery. The complications and its management are summarized in Table 2.
Lateral facial profiles of both patients. A: During distraction. B: Reasonable and stable result at 18 months postdistraction.
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FIGURE 4 Photos of patient 1, who had more severe exorbitism showing full orbital protection after monobloc DO. A: Preoperative. B: After 5 months of consolidation. C: At 18 months postdistraction.
Both patients later underwent two additional procedures under general anesthesia. The first procedure was for the removal of the external frame and wound revision in the temporal region. The second surgery was for the removal of the internal distractors and plates. The distraction procedure successfully solved the chronic functional problems associated with the orbital proptosis secondary to severe fronto-orbital hypoplasia and obstructed nasopharyngeal airway secondary to severe midface hypoplasia. The patients’ preoperative and sequential postoperative images are shown in Figure 2. Follow up at 18 months after distraction showed successful outcomes, as evidenced by the acceptable facial profile (Fig. 3) and the ability of both
patients to close the eyelids, resulting in adequate eye protection (Fig. 4). Nasopharyngeal airway patency in both patients was confirmed via postoperative airway analysis (Fig. 5) and endoscopic procedures (Fig. 6) prior to decannulation. DISCUSSION In the treatment of syndromic craniosynostosis, surgical interventions can be performed conventionally or integrated with DO when superior segmental advancement is indicated. Various surgical techniques, such as conventional Le Fort III osteotomy, Le Fort III DO, simultaneous Le Fort III and Le Fort I osteotomy, Le Fort II osteotomy
FIGURE 5 Pre- and postoperative airway analysis of patient 2 showing improvement of upper airway cross sections and diameters.
Hariri et al., MONOBLOC DISTRACTION OSTEOGENESIS IN CROUZON SYNDROME
FIGURE 6
123
Endoscopic images at different levels showing adequate nasopharyngeal airway patency in patient 1 prior to his decannulation.
with zygomatic repositioning, and monobloc minus Le Fort II DO, have been reported, with favorable functional and cosmetic results when performed in patients with syndromic craniosynostosis (Nout et al., 2008; Hariri et al., 2011; Hopper et al., 2013; Paliga et al., 2013). Clinically, the distraction technique allows the surgeons to monitor facial advancement progressively and make the decision to stop distraction when the desired clinical outcome has been achieved. The technique produces improvements in appearance and functional parameters and significantly reduces operative time by eliminating bone graft harvesting compared to a conventional monobloc procedure (Witherow et al., 2008). Le Fort II DO with simultaneous zygomatic repositioning has been reported to produce a significant improvement in facial ratios when compared to Le Fort III DO due to the focus on central component advancement (Hopper et al., 2013). Another innovative surgical technique involving a simultaneous monobloc minus Le Fort II DO to allow independent multisegmental vector movement was reported to achieve both functional and cosmetic success in a patient with Apert syndrome (Paliga et al., 2013). Nevertheless, the choice of surgical technique should be based on the ultimate aim of removing the patient’s functional impairment, the multdirectional magnitude of surgical movement required, and other patient-related aspects such as age and growth status. With regard to DO, the application of internal distractors at the zygomatic bones advances the lateral midfacial skeleton farther than the central midface, and the force exerted on the lateral region can be high, thus leading to frequent fracture, as this region is often hypoplastic in severe craniofacial deformity (Gosain et al., 2002). On the other hand, the use of a single rigid external distraction device has the advantages of easier application, a traction focus that is located at the central midface component, and the capacity for multivector control, thus optimizing rehabilitation of nasopharyngeal airway patency and achieving 3D facial concavity (Polley et al., 1995; Pelo et al., 2007; Witherow et al., 2008; Gasparini et al., 2012). Taking into consideration the complicated surgical history of both patients, we decided to use a combination of both types of distraction devices to achieve optimum stability, maximize functional results, and minimize anticipated
complications. Nevertheless, with the use of both internal and external devices, the vector control was restricted to a single vector movement. The amount of segmental advancement achieved in both our patients (27 mm and 23 mm) was determined from the total amount of activation, based on the activation protocol and length of the distraction rods. These figures are comparable to other reports (Polley et al., 1995; Witherow et al., 2008; Meling et al., 2011). However, the true measurement of segmental advancement can be evaluated by measuring the radiographic distance from sella to nasion and sella to maxillary A-point to determine the upper and lower facial advancement, respectively (Witherow et al., 2008). The analysis by Witherow et al. (2008) of three reference points (sella, nasion, and A-point) and distractor activation showed no relationship between distractor activation and the actual distance of midface movement. An adequate consolidation period minimizes relapse, and our protocol was comparable to that used in other studies (Meling et al., 2011; Marchac and Arnaud, 2012; Nishimoto et al., 2012). To ensure segmental stability in both patients, the external frame was kept for an additional 1 month following completion of the distraction phase, while the internal devices continuously functioned as temporary rigid fixation during the consolidation period after the external frame was removed. In both patients, multiple cyanotic episodes, especially when in flat position, necessitated early tracheostomy to bypass the obliterated nasopharyngeal airway. Hence, polysomnography was not needed. Pre- and postsurgical airway analysis (Fig. 5) using Vultus software (3dMD, Atlanta, GA) and sleep endoscopy (Fig. 6) showed favorable cross-sectional airway changes. These findings confirmed restoration of nasopharyngeal airway patency in both patients prior to their decannulation. This vital functional improvement was also demonstrated in a study conducted by Witherow et al. (2008), who reported significant improvements in airway obstruction in craniofacial deformity patients with abnormal polysomnography. Because the risk of structural relapse leading to the narrowing of the nasopharyngeal airway remains unpredictable, periodic polysomnography was proposed to the parents of both patients to further assess any progressive
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FIGURE 7 Presurgical planning. A: Prebent footplates for the internal distractor (yellow arrows) and prefabricated fenestrated titanium mesh for the stabilizing pins of the external distractor (red arrow). B: Planned fixation of two anchoring pins in the glabella region. C: Planned fixation of two anchoring pins in the piriform region.
airway obliteration and the possible reoccurrence of obstructive sleep apnea syndrome. Serious complications arising from monobloc advancement include mortality, severe blood loss, dural tear, CSF leak, ascending infection, and frontal bone necrosis (Witherow et al., 2008; Meling et al., 2011; Dunaway et al., 2012). A study done by Meling et al. (2011) showed that complications in both monobloc distraction and conventional surgery are comparable. One of our patients had an inadvertent small dural tear intraoperatively, which was managed with onlay placement of Surgicel (Ethicon, Miami, FL) over the thinned out dura, which would not hold a stitch. Postoperatively, he developed CSF rhinorrhea for 2 weeks and was managed conservatively. According to the literature, CSF leaks following monobloc distraction are common, with incidence ranging from 2% to 20%; most of these leaks settle spontaneously (Dunaway et al., 2012). Patient 1 also developed right eye exodeviation with limited abduction secondary to direct impingement of the lateral rectus muscle from the distracted orbital bone segment near the lateral aspect of the eyeball. The bony impingement was surgically relieved by a piezosurgical cutting tool, and the divergent lateral orbital wall was outfractured to resolve the eye abduction and enable lateral eye movement (Hariri et al., 2014). The integration of computer-aided design/manufacture technology in the field of craniofacial surgery has greatly benefited the perioperative aspects of medical treatment, especially in the fabrication of surgical templates to produce precise surgical outcomes (Paliga et al., 2013; Khechoyan et al., 2014; Mardini et al., 2014). In both our cases, the internal distractor footplates were prebent and fixed to the 3D biomodel (Fig. 7A), and the ideal positions for the four
anchoring pins and plates for the external device were predetermined to allow full surgical simulation, thus enabling surgical vector assessment (Fig. 7B and 7C). Precise fixation reduces operating time, and accurate midface movement leads to a satisfactory final outcome. Intraoperatively, we used a piezoelectric handpiece to perform the intracranial cut to minimize the risk of traumatizing the dural layer and associated visceral organs. The surgical modification of the Le Fort III osteotomy in the medial canthal dissection causes minimal widening of the inner canthal distance and can be completed without any orbital incision, thus minimizing periorbital edema in the early postoperative period (Cheung et al., 1998). The use of bilateral fenestrated titanium mesh directly underneath the stabilizing pin in the temporal region (Fig. 7A) minimized the potential risks of perforating the thin cranial bone if too much force had been applied. In conclusion, these case reports illustrate the clinical outcomes of the monobloc Le Fort III DO procedure using a combination of external and internal devices in preserving and rehabilitating vital functional problems secondary to severe craniofacial discrepancy in two patients with Crouzon syndrome. Comprehensive presurgical planning and a precise surgical technique allowed massive segmental advancement, allowing the desired functional outcomes. REFERENCES Cheung LK, Samman N, Tideman H. A modified approach to the Le Fort II osteotomy. Ann R Australas Coll Dent Surg. 1998;14:107– 113. Dunaway DJ, Britto JA, Abela C, Evans RD, Owase Jeelani NU. Complications of frontofacial advancement. Childs Nerv Syst. 2012;28:1571–1576.
Hariri et al., MONOBLOC DISTRACTION OSTEOGENESIS IN CROUZON SYNDROME
Gasparini G, Di Rocco C, Tamburrini G, Pelo S. External craniofacial osteodistraction in complex craniosynostoses. Childs Nerv Syst. 2012;28:1565–1570. Gosain AK, Santoro TD, Havlik RJ, Cohen SR, Holmes RE. Midface distraction following Le Fort III and monobloc osteotomies: problems and solutions. Plast Reconstr Surg. 2002;109:1797–1808. Hariri F, Cheung LK, Rahman ZA, Ramasamy SN, Ganesan D. A rare orbital complication of eye exodeviation with limited abduction during monobloc Le Fort III distraction osteogenesis. Cleft Palate Craniofac J. 2015;52:489–493. Hariri F, Lan TH, Cheung LK. Simultaneous Le Fort III and Le Fort I osteotomies for correction of midface hypoplasia in Crouzon syndrome. Asian J Oral Maxillofac Surg. 2011;23:128–133. Hopper RA, Kapadia H, Morton T. Normalizing facial ratios in Apert syndrome patients with Le Fort II midface distraction and simultaneous zygomatic repositioning. Plast Reconstr Surg. 2013;132:129–140. Jacobsen HC, Sieg P, Hakim SG. Combined internal and external distraction of the midface for the treatment of Crouzon syndrome and critical obstructive sleep apnea: a case report. J Oral Maxillofac Surg. 2009;67:2004–2009. Khechoyan DY, Saber NR, Burge J, Fattah A, Drake J, Forrest CR, Phillips JH. Surgical outcomes in craniosynostosis reconstruction: the use of prefabricated templates in cranial vault remodelling. J Plast Reconstr Aesthet Surg. 2014;67:9–16. Marchac A, Arnaud E. Cranium and midface distraction osteogenesis: current practices, controversies, and future applications. J Craniofac Surg. 2012;23:235–238. Mardini S, Alsubaie S, Cayci C, Chim H, Wetjen N. Threedimensional preoperative virtual planning and template use for surgical correction of craniosynostosis. J Plast Reconstr Aesthet Surg. 2014;67:336–343. Meling TR, Høgevold HE, Due-Tønnessen BJ, Skjelbred P. Comparison of perioperative morbidity after Le Fort III and monobloc
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distraction osteogenesis. Br J Oral Maxillofac Surg. 2011;49:131– 134. Nishimoto S, Oyama T, Tei S, Seike S, Nagashima T, Kawai K, Kakibuchi M. ‘‘Bibloc advancement’’ with a combination of internal and external distracters. J Craniofac Surg. 2012;23:1444– 1447. Nout E, Cesteleyn LL, van der Wal KG, van Adrichem LN, Mathijssen IM, Wolvius EB. Advancement of the midface, from conventional Le Fort III osteotomy to Le Fort III distraction: review of the literature. Int J Oral Maxillofac Surg. 2008;37:781– 789. Ortiz-Monasterio F, del Campo AF, Carrillo A. Advancement of the orbits and the midface in one piece, combined with frontal repositioning, for the correction of Crouzon’s deformities. Plast Reconstr Surg. 1978;61:507–516. Paliga JT, Goldstein JA, Storm PB, Taylor JA. Monobloc minus Le Fort II for single-stage treatment of the Apert phenotype. J Craniofac Surg. 2013;24:1380–1382. Pelo S, Gasparini G, Di Petrillo A, Tamburrini G, Di Rocco C. Distraction osteogenesis in the surgical treatment of craniostenosis: a comparison of internal and external craniofacial distractor devices. Childs Nerv Syst. 2007;23:1447–1453. Polley JW, Figueroa AA, Charbel FT, Berkowitz R, Reisberg D, Cohen M. Monobloc craniomaxillofacial distraction osteogenesis in a newborn with severe craniofacial synostosis: a preliminary report. J Craniofac Surg. 1995;6:421–423. Posnick JC, Ruiz RL, Tiwana PS. Craniofacial dysostosis syndromes: stages of reconstruction [review article]. Oral Maxillofac Surg Clin North Am. 2004;16:475–491. Witherow H, Dunaway D, Evans R, Nischal KK, Shipster C, Pereira V, Hearst D, White M, Jones BM, Hayward R. Functional outcomes in monobloc advancement by distraction using the rigid external distractor device. Plast Reconstr Surg. 2008;121:1311– 1322.
CASE REPORT Monobloc Le Fort III Distraction Osteogenesis for Correction of Severe Fronto-orbital and Midface Hypoplasia in Pediatric Crouzon Syndrome Firdaus Hariri, M.B.B.S., B.D.S., M.D.S.(O.M.F.S.), Lim Kwong Cheung, B.D.S., F.F.D.R.C.S., Ph.D., Zainal Ariff Abdul Rahman, B.D.S., M.Sc., F.D.S.R.C.S., Vickneswaran Mathaneswaran, M.B.B.S., F.R.C.S., Dharmendra Ganesan, M.B.B.S., M.Surg., F.R.C.S. In severe syndromic craniosynostosis, distraction osteogenesis (DO) provides superior segmental advancement and allows progressive clinical monitoring to ensure that adequate skeletal expansion is achieved. We report two cases of Crouzon syndrome involving a 3-year-old boy and a 4-year-old girl, who were both treated with monobloc Le Fort III DO using a combination of external and internal distraction devices (Synthes, Oberdorf, Switzerland) to treat severe orbital proptosis and obstructed nasopharyngeal airway secondary to severe hypoplastic craniofacial skeletal components. Their skeletal segments were advanced in daily increments by 27 mm and 23 mm, respectively. Results at 18 months postoperatively showed successful outcomes, as evidenced by adequate eye protection, tracheostomy tube decannulation following objective evidence of patent nasopharyngeal airway, and acceptable facial appearance. Monobloc Le Fort III DO using a combination of external and internal devices produces favorable functional and clinical outcomes for the treatment of severe orbital and airway discrepancy in Crouzon syndrome. KEY WORDS:
craniofacial surgery, Crouzon syndrome, distraction osteogenesis, monobloc Le Fort III
Traditionally, the craniofacial deformity has been treated with conventional fronto-orbital advancement, which was introduced by Ortiz-Monasterio et al. (1978) and has proven to be a reliable surgical procedure to treat symptomatic syndromic craniosynostosis. However, in a severely hypoplastic patient, a large segmental advancement is needed, requiring the gap to be grafted and stabilized. Large advancement may require sufficient bone grafting and soft tissue for primary wound closure, of which both are limited in pediatric calvaria. The use of plates has been reported, but migration of titanium plates and the instability of resorbable plates limit their application (Dunaway et al., 2012). Inadequate stability secondary to soft tissue limitation and unstable bone segment fixation after significant advancement may cause the graft to resorb, leading to a less than ideal long-term outcome. The application of distraction osteogenesis (DO) in treating syndromic craniofacial patients began in the mid1990s and has since become widely used, with many articles reporting on the use of either external or internal devices (Polley et al., 1995; Gosain et al., 2002; Witherow et al., 2008; Meling et al., 2011; Marchac and Arnaud, 2012). A literature search found limited data on the application of a combination of external and internal distractors for advancing a monobloc Le Fort III segment in syndromic craniosynostosis (Jacobsen et al., 2009; Marchac and Arnaud, 2012; Nishimoto et al., 2012). The objective of this study is to evaluate two patients with pediatric Crouzon
Conventional monobloc Le Fort III osteotomy is an established surgical procedure to treat syndromic craniosynostosis conditions, such as Crouzon syndrome, in pediatric patients. In Crouzon syndrome, patients typically present with hypoplastic midface with orbital proptosis and additional orbital dystopia that may produce orbital hypertelorism (Posnick et al., 2004). In severe cases, patients may also present with significant upper airway obstruction, with progressive obstructive sleep apnea secondary to a severely hypoplastic maxilla, which may eventually require tracheostomy to bypass the obstructed airway.
Dr. Hariri is Senior Lecturer, Department of Oro-Maxillofacial Surgical and Medical Sciences, Faculty of Dentistry, University of Malaya, Malaysia. Dr. Cheung is Professor, Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Dr. Abdul Rahman is Professor, Department of Oro-Maxillofacial Surgical and Medical Sciences, Faculty of Dentistry, University of Malaya, Malaysia. Dr. Mathaneswaran and Dr. Ganesan are Professor, Neurosurgery Unit, Department of Surgery, Faculty of Medicine, University of Malaya, Malaysia. Grant: University of Malaya’s HIR-MOHE research grant initiative (HIR Ref No: UM.C/625/1/HIR-MOHE/12). Submitted July 2014; Revised October 2014; Accepted October 2014. Address correspondence to: Dr. Firdaus Hariri, Department of OroMaxillofacial Surgical and Medical Sciences, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia. E-mail fi[email protected]. DOI: 10.1597/14-210 118
Hariri et al., MONOBLOC DISTRACTION OSTEOGENESIS IN CROUZON SYNDROME
TABLE 1 Patient 1
Patients’ Surgical Background Prior to Monobloc Le Fort III Distraction Osteogenesis
Age, y 3
Gender Male
Diagnoses
Crouzon syndrome Severe obstructive sleep apnea
Surgical History
2
119
4
Female
Crouzon syndrome Severe obstructive sleep apnea
Bilateral tarsorrhaphy Right eye amniotic membrane transplant with tarsorrhaphy and silicone sheet attachment First fronto-orbital advancement Second fronto-orbital advancement Ventriculoperitoneal shunt insertion Right eye tarsorrhaphy repair Ventriculoperitoneal shunt revision Second ventriculoperitoneal shunt revision Third ventriculoperitoneal shunt revision Third fronto-orbital advancement and cranioplasty Tracheostomy Removal of titanium screws and plate Ventriculoperitoneal shunt First fronto-orbital advancement Second fronto-orbital advancement Endoscopic adenoidectomy Tracheostomy
syndrome treated by DO using a combination of external and internal distraction devices and to review some critical issues regarding the application of DO in craniofacial surgery. CASE REPORT We report two cases, a 3-year-old boy and a 4-year-old girl, who were both diagnosed with Crouzon syndrome. Both patients presented with severe orbital proptosis and obstructive sleep apnea secondary to a severely hypoplastic midface. Both patients had undergone multiple surgical procedures involving conventional fronto-orbital advancement to decompress the cranial cavity and salvage the function of the eyes and had undergone tracheostomy to bypass the obstructed upper airway. Patient 1 underwent tarsorrhaphy on both eyes after birth but eventually developed right eye blindness secondary to persistent corneal abrasion damage resulting from severe exorbitism. The medical histories of both patients are summarized in Table 1.
The management of pediatric craniofacial cases in our center involves a multidisciplinary team from the departments of oral and maxillofacial surgery, neurosurgery, otolaryngology, ophthalmology, clinical genetics, anesthesiology, and pediatric respiration. Clinical and imaging assessments resulted in skeletal diagnoses of a combination of severe fronto-zygomatico-naso-maxillary hypoplasia and Angle Class III malocclusion for both patients. We performed a comprehensive presurgical craniomaxillofacial protocol for both patients, which consisted of clinical evaluation, computed tomography scan, presurgical airway analysis (3dMD, Atlanta, GA), and simulation surgery using Surgicase software (Materialize, Leuven, Belgium) combined with three-dimensional (3D) biomodel simulation surgery and prebending of distractor footplates to achieve precision (Fig. 1). Both patients’ surgical plans were finalized with a goal of maximum segmental advancement to achieve adequate eye protection and open the nasopharyngeal airway. As such, a surgical procedure, monobloc Le Fort III DO, that used a combination of external and internal devices was planned to achieve the aforementioned aims for both patients.
FIGURE 1 Presurgical planning images for patient 2. A: Airway analysis. B: Surgicase software surgical simulation. C: Surgical simulation of stereomodel and adaptation of distraction devices.
None None 6
Conservative: antibiotics, close monitoring, and distraction rate reduction Surgical exploration Leakage of cerebrospinal fluid Right eye exodeviation with limited abduction 5
5 2
1.0–1.5
2–3
23
1 month after completion of distraction phase 27 2–3 1.0–1.5 5 1
Total Advancement, mm Activation Frequency, Turns/d Distraction Rate, mm/d Latency Period, d Patient
Summary of Patients’ Distraction Protocols and Complications
Removal of External Frame
Consolidation Phase, mo
Complication Associated with Distraction Procedure
Management
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TABLE 2
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Both patients successfully underwent the monobloc Le Fort III DO via a combination of coronal and intraoral approaches. The surgical procedure started with a frontal bone craniotomy, followed by Le Fort III osteotomy. During the Le Fort III procedure, a slight modification was performed; the anterior limb of the medial canthal ligament at the medial orbital rims was detached from the fronto-maxillary bony process on either side, as described by Cheung et al. (1998). This exposed the lacrimal sac, which was reflected to expose the lacrimal groove. The dissection was continued inferiorly along the infraorbital rim as far laterally as possible. Separation of the nasal septum from the skull base was achieved with a septal osteotome, which was inserted through the nasal bone osteotomy cut to engage the perpendicular cribiform plate. An intraoral approach was performed to complete the pterygomaxillary dysjunction. The removed frontal bone was then fixed to the supraorbital rim of the Le Fort III segment. To ensure stability and optimum segmental advancement, we used both an external midface distractor and two internal craniomaxillofacial distractors (Synthes, Oberdorf, Switzerland). The external midface distractor consisted of two zygomatic plates with percutaneous pins, placed bilaterally at the glabella region, and another two plates in the maxilla, placed bilaterally just lateral to the piriform rim. The two internal distractors with prebent footplates were fixed according to the predetermined sites according to a presurgical stereomodel plan. Trial activation of the internal devices was performed before wound closure. The rigid external distractor frame was positioned after the wound closure. Alignment of the frame was checked to ensure its stability and determine the principal distraction vector. All surgical stages proceeded uneventfully. Two subcutaneous vacuum drains were placed, and both patients were kept in the pediatric intensive care unit for close observation for 48 hours. Both patients were given antibiotics and corticosteroids upon induction of general anesthesia and postoperatively. In terms of the distraction protocol, both patients had a latency period of 5 days. The distractors were activated two to three times a day to achieve 1.0 to 1.5 mm of movement per day. The wounds were cleaned and checked, and both patients were given analgesic syrup prior to activation. In total, six distraction points were activated in each patient; two were from the internal distractors and four were from the anchoring rods of the external distractors. All six points were activated by the same amount. The segmental advancement achieved was 27 mm in patient 1 and 23 mm in patient 2, based on the total activation amount from the protocol. The activation amount was routinely crosschecked with the length of the anchoring rods of external distractors to ensure consistency. The decision to stop activation was based on clinical assessment of eyelid closure, with slight overcorrection, and adequate nasopharyngeal opening based on an endoscopic procedure. The
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FIGURE 2 Pre- and postoperative photos of Patient 1 and Patient 2. A: Preoperative appearance. B: Activation phase. C: After 3 months of consolidation, with the external distractor removed. D: At 10 months postdistraction. E: At 18 months postdistraction.
consolidation period was 5 months for patient 1 and 6 months for patient 2. A summary of the distraction protocol is summarized in Table 2. Patient 1 was noted to have a cerebrospinal fluid (CSF) leak at 2 weeks postoperatively. The condition was treated conservatively with close monitoring, antibiotics, and reduction of the distraction rate. He also developed right eye exodeviation with limited abduction, which was noted when the advancement
FIGURE 3
reached 23 mm (Hariri et al., 2015). An urgent computed tomographic scan showed that there was an impingement of the lateral rectus muscle in the globe region from the distracted segment. A surgical procedure to relieve the impingement was performed, and eye function had returned to normal 2 weeks after the procedure. Patient 2 had an uneventful recovery. The complications and its management are summarized in Table 2.
Lateral facial profiles of both patients. A: During distraction. B: Reasonable and stable result at 18 months postdistraction.
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FIGURE 4 Photos of patient 1, who had more severe exorbitism showing full orbital protection after monobloc DO. A: Preoperative. B: After 5 months of consolidation. C: At 18 months postdistraction.
Both patients later underwent two additional procedures under general anesthesia. The first procedure was for the removal of the external frame and wound revision in the temporal region. The second surgery was for the removal of the internal distractors and plates. The distraction procedure successfully solved the chronic functional problems associated with the orbital proptosis secondary to severe fronto-orbital hypoplasia and obstructed nasopharyngeal airway secondary to severe midface hypoplasia. The patients’ preoperative and sequential postoperative images are shown in Figure 2. Follow up at 18 months after distraction showed successful outcomes, as evidenced by the acceptable facial profile (Fig. 3) and the ability of both
patients to close the eyelids, resulting in adequate eye protection (Fig. 4). Nasopharyngeal airway patency in both patients was confirmed via postoperative airway analysis (Fig. 5) and endoscopic procedures (Fig. 6) prior to decannulation. DISCUSSION In the treatment of syndromic craniosynostosis, surgical interventions can be performed conventionally or integrated with DO when superior segmental advancement is indicated. Various surgical techniques, such as conventional Le Fort III osteotomy, Le Fort III DO, simultaneous Le Fort III and Le Fort I osteotomy, Le Fort II osteotomy
FIGURE 5 Pre- and postoperative airway analysis of patient 2 showing improvement of upper airway cross sections and diameters.
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FIGURE 6
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Endoscopic images at different levels showing adequate nasopharyngeal airway patency in patient 1 prior to his decannulation.
with zygomatic repositioning, and monobloc minus Le Fort II DO, have been reported, with favorable functional and cosmetic results when performed in patients with syndromic craniosynostosis (Nout et al., 2008; Hariri et al., 2011; Hopper et al., 2013; Paliga et al., 2013). Clinically, the distraction technique allows the surgeons to monitor facial advancement progressively and make the decision to stop distraction when the desired clinical outcome has been achieved. The technique produces improvements in appearance and functional parameters and significantly reduces operative time by eliminating bone graft harvesting compared to a conventional monobloc procedure (Witherow et al., 2008). Le Fort II DO with simultaneous zygomatic repositioning has been reported to produce a significant improvement in facial ratios when compared to Le Fort III DO due to the focus on central component advancement (Hopper et al., 2013). Another innovative surgical technique involving a simultaneous monobloc minus Le Fort II DO to allow independent multisegmental vector movement was reported to achieve both functional and cosmetic success in a patient with Apert syndrome (Paliga et al., 2013). Nevertheless, the choice of surgical technique should be based on the ultimate aim of removing the patient’s functional impairment, the multdirectional magnitude of surgical movement required, and other patient-related aspects such as age and growth status. With regard to DO, the application of internal distractors at the zygomatic bones advances the lateral midfacial skeleton farther than the central midface, and the force exerted on the lateral region can be high, thus leading to frequent fracture, as this region is often hypoplastic in severe craniofacial deformity (Gosain et al., 2002). On the other hand, the use of a single rigid external distraction device has the advantages of easier application, a traction focus that is located at the central midface component, and the capacity for multivector control, thus optimizing rehabilitation of nasopharyngeal airway patency and achieving 3D facial concavity (Polley et al., 1995; Pelo et al., 2007; Witherow et al., 2008; Gasparini et al., 2012). Taking into consideration the complicated surgical history of both patients, we decided to use a combination of both types of distraction devices to achieve optimum stability, maximize functional results, and minimize anticipated
complications. Nevertheless, with the use of both internal and external devices, the vector control was restricted to a single vector movement. The amount of segmental advancement achieved in both our patients (27 mm and 23 mm) was determined from the total amount of activation, based on the activation protocol and length of the distraction rods. These figures are comparable to other reports (Polley et al., 1995; Witherow et al., 2008; Meling et al., 2011). However, the true measurement of segmental advancement can be evaluated by measuring the radiographic distance from sella to nasion and sella to maxillary A-point to determine the upper and lower facial advancement, respectively (Witherow et al., 2008). The analysis by Witherow et al. (2008) of three reference points (sella, nasion, and A-point) and distractor activation showed no relationship between distractor activation and the actual distance of midface movement. An adequate consolidation period minimizes relapse, and our protocol was comparable to that used in other studies (Meling et al., 2011; Marchac and Arnaud, 2012; Nishimoto et al., 2012). To ensure segmental stability in both patients, the external frame was kept for an additional 1 month following completion of the distraction phase, while the internal devices continuously functioned as temporary rigid fixation during the consolidation period after the external frame was removed. In both patients, multiple cyanotic episodes, especially when in flat position, necessitated early tracheostomy to bypass the obliterated nasopharyngeal airway. Hence, polysomnography was not needed. Pre- and postsurgical airway analysis (Fig. 5) using Vultus software (3dMD, Atlanta, GA) and sleep endoscopy (Fig. 6) showed favorable cross-sectional airway changes. These findings confirmed restoration of nasopharyngeal airway patency in both patients prior to their decannulation. This vital functional improvement was also demonstrated in a study conducted by Witherow et al. (2008), who reported significant improvements in airway obstruction in craniofacial deformity patients with abnormal polysomnography. Because the risk of structural relapse leading to the narrowing of the nasopharyngeal airway remains unpredictable, periodic polysomnography was proposed to the parents of both patients to further assess any progressive
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FIGURE 7 Presurgical planning. A: Prebent footplates for the internal distractor (yellow arrows) and prefabricated fenestrated titanium mesh for the stabilizing pins of the external distractor (red arrow). B: Planned fixation of two anchoring pins in the glabella region. C: Planned fixation of two anchoring pins in the piriform region.
airway obliteration and the possible reoccurrence of obstructive sleep apnea syndrome. Serious complications arising from monobloc advancement include mortality, severe blood loss, dural tear, CSF leak, ascending infection, and frontal bone necrosis (Witherow et al., 2008; Meling et al., 2011; Dunaway et al., 2012). A study done by Meling et al. (2011) showed that complications in both monobloc distraction and conventional surgery are comparable. One of our patients had an inadvertent small dural tear intraoperatively, which was managed with onlay placement of Surgicel (Ethicon, Miami, FL) over the thinned out dura, which would not hold a stitch. Postoperatively, he developed CSF rhinorrhea for 2 weeks and was managed conservatively. According to the literature, CSF leaks following monobloc distraction are common, with incidence ranging from 2% to 20%; most of these leaks settle spontaneously (Dunaway et al., 2012). Patient 1 also developed right eye exodeviation with limited abduction secondary to direct impingement of the lateral rectus muscle from the distracted orbital bone segment near the lateral aspect of the eyeball. The bony impingement was surgically relieved by a piezosurgical cutting tool, and the divergent lateral orbital wall was outfractured to resolve the eye abduction and enable lateral eye movement (Hariri et al., 2014). The integration of computer-aided design/manufacture technology in the field of craniofacial surgery has greatly benefited the perioperative aspects of medical treatment, especially in the fabrication of surgical templates to produce precise surgical outcomes (Paliga et al., 2013; Khechoyan et al., 2014; Mardini et al., 2014). In both our cases, the internal distractor footplates were prebent and fixed to the 3D biomodel (Fig. 7A), and the ideal positions for the four
anchoring pins and plates for the external device were predetermined to allow full surgical simulation, thus enabling surgical vector assessment (Fig. 7B and 7C). Precise fixation reduces operating time, and accurate midface movement leads to a satisfactory final outcome. Intraoperatively, we used a piezoelectric handpiece to perform the intracranial cut to minimize the risk of traumatizing the dural layer and associated visceral organs. The surgical modification of the Le Fort III osteotomy in the medial canthal dissection causes minimal widening of the inner canthal distance and can be completed without any orbital incision, thus minimizing periorbital edema in the early postoperative period (Cheung et al., 1998). The use of bilateral fenestrated titanium mesh directly underneath the stabilizing pin in the temporal region (Fig. 7A) minimized the potential risks of perforating the thin cranial bone if too much force had been applied. In conclusion, these case reports illustrate the clinical outcomes of the monobloc Le Fort III DO procedure using a combination of external and internal devices in preserving and rehabilitating vital functional problems secondary to severe craniofacial discrepancy in two patients with Crouzon syndrome. Comprehensive presurgical planning and a precise surgical technique allowed massive segmental advancement, allowing the desired functional outcomes. REFERENCES Cheung LK, Samman N, Tideman H. A modified approach to the Le Fort II osteotomy. Ann R Australas Coll Dent Surg. 1998;14:107– 113. Dunaway DJ, Britto JA, Abela C, Evans RD, Owase Jeelani NU. Complications of frontofacial advancement. Childs Nerv Syst. 2012;28:1571–1576.
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