ORIGINAL ARTICLE
Three-Dimensional Airways Reconstruction in Syndromic Pedriatric Patients Following Mandibular Distraction Osteogenesis Giuseppe Spinelli, MD, DDS, Tommaso Agostini, MD, Francesco Arcuri, MD, Marco Conti, MD, and Mirco Raffaini, MD, PhD Background: Airway obstruction, associated with mandibular hypoplasia, is a frequent complication in syndromic pediatric patients. The clinical signs of airway obstruction change from mild positional obstruction to severe respiratory distress with cyanosis. The young age of the patients makes medical management extremely complex. Methods: The purpose was to evaluate the success of surgery, evaluating the expansion of the respiratory volumes measured by computer tomography analyzed through a software (SimPlant Pro 15). Twelve patients with mandibular hypoplasia and respiratory distress were treated between December 2010 and December 2013. Eleven of them had tracheostomy in the preoperative period. The goal of surgery was to prevent permanent tracheostomy or to remove it, if present. Results: Volume and surface area increased by an average of 279.2% and 89.4%, respectively. Tracheostomy was avoided in 1 patient who underwent surgery precociously, and it was removed in 10 patients. Only 1 case failed in volume airway augmentation, and tracheostomy was not removed. Conclusions: Computer tomography can calculate the cross-sectional areas of the airway in 3 planes of space: coronal, sagittal, and axial. In most patients, changes in airways have been accompanied by improvements in sleep and breathing, allowing for the removal of tracheostomy with an improved quality of life. Three-dimensional reconstruction of airways revealed a useful tool to better understand the success of surgery. Level of evidence: IV. Key Words: Distraction osteogenesis, syndromic patients, respiratory distress, three-dimensional CT scan, tracheostomy (J Craniofac Surg 2015;26: 650–654)
M
anagement of airway obstruction associated with mandibular hypoplasia is a challenging condition in pediatric patients affected by severe craniofacial malformations such as Pierre Robin sequence or Stickler syndrome, Crouzon syndrome, Treacher From the Department of Maxillo-Facial Surgery, CTO-AOUC, University of Florence, Florence, Italy. Received June 21, 2014. Accepted for publication October 28, 2014. Address correspondence and reprint requests to Tommaso Agostini, MD, Department of Maxillo-Facial Surgery, University of Florence, Largo Palagi 1, Florence, Italy; E-mail: [email protected] The authors report no conflict of interest. Copyright # 2015 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001421
650
Collins syndrome, Goldenhar syndrome, Freeman-Sheldon syndrome, Nager syndrome, or other diseases that include mandibular hypoplasia. Clinical signs of airway obstruction change from mild positional obstruction to severe life-threatening respiratory distress with cyanosis. Perinatal airway obstruction varies in severity from mild, moderate, to severe, with risk of complete obstruction and mortality from cor pulmonale due to respiratory failure. Because of the frequent concomitant cleft palate, these pediatric patients can demonstrate feeding difficulties, which can require specialized nipples, obturators, or nasogastric tubes.1– 4 Management of respiratory distress can be both medical and surgical. Depending on the degree of severity, different conservative options have been described to correct the obstructed airway in the neonatal period of syndromic pediatric patients with hypoplastic mandible. Mild airway obstruction can be managed by positional therapy (prone or lateral position) with neck extension or by continuous positive airway pressure. In the moderate cases, nasal stents with a small-diameter endotracheal tube can be used to prevent glossoptosis and consequent obstruction of the posterior pharyngeal wall. For moderate to severe airway obstruction, a surgical treatment is mandatory.5 –8 With regard to invasive procedures, tracheotomy, tongue lip adhesion, and mandibular distraction osteogenesis (DO) are commonly performed and widely accepted. For the severely compromised airway obstruction, tracheostomy immediately solves the problem. However, this surgical solution is frequently characterized by perioperative (hypotension, cardiac arrhythmias, pneumothorax, bleeding, peritracheal insertion) and postoperative complications/sequelae (tube occlusion/ displacement, vocal cord paralysis, tracheoesophageal fistula, subcutaneous emphysema, scarring and granuloma formation, tracheomalacia, tracheal stenosis).9,10 Tongue lip adhesion was first described by Douglas11,12 in 1946, and it was characterized by an extremely low success rate. After that, Denny13 has shown the unpredictable results of this procedure. He reported an 18% success rate; the majority of the patients required further procedure to solve the airway or feeding problems.11–13 Finally, since the 1990 s, DO has been successfully used to control the airway obstruction in pediatric patients affected by severe craniofacial malformations with congenital hypoplastic mandible. Distraction osteogenesis enlarges the pharyngeal region by lengthening the mandible and advancing the base of the tongue off the posterior pharyngeal wall. Tracheotomy can be avoided, or if present, it can be removed during or after mandibular distraction. Although the excellent results of DO applied to patients affected by mandibular hypoplasia and airway obstruction localized in the pharyngeal region above the level of the vocal cords, several complications are described such as device failures, scarring, pin loosening/infection, premature bone consolidation, nerve or tooth buds injuries, joint ankylosis, pneumonitis, and failure to decannulate the tracheostomy or control the airway obstruction.14,15 Congenital hypoplastic mandible is frequently associated with an
The Journal of Craniofacial Surgery
Volume 26, Number 3, May 2015
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Volume 26, Number 3, May 2015
abnormal upper airway and an increased collapse of the pharynx leading to obstructive sleep apnea. Mandibular distraction improves breathing and oxygenation by lengthening the mandible and normalizing the upper airway in terms of size and shape. Pediatric and adult normal values for 16 parameters of the size and shape of the upper airway have been recently described.16–19
STUDY DESIGN The purpose of this retrospective study was to evaluate the postoperative three-dimensional changes of the upper airway of pediatric patients after DO in terms of size and shape. The aims were to evaluate the areas and the volumes of the airway anatomy with a three-dimensional computed tomographic (CT) analysis and to compare the preoperative and postoperative results in children with syndromic hypoplastic mandible and obstructive sleep apnea, who received DO. The hypothesis was that mandibular distraction would increase the airway size and would change the airway shape with a better control of the obstructive sleep apnea. To address this hypothesis, we enrolled a cohort of pediatric patients with hypoplastic mandible who received mandibular DO. Medical records and radiological findings of 26 patients with mandibular hypoplasia and respiratory distress treated in the period between December 2010 and December 2013 were reviewed. All patients presented an apnea/hypopnea index of greater than 1 and obstruction of the base of tongue evaluated by nasoendoscopy and bronchoscopy. Inclusion criteria were (1) syndromic hypoplastic mandible, (2) mandibular advancement by DO, and (3) preoperative and postoperative three-dimensional CT images. Exclusion criteria were (1) children without hypoplastic mandible, (2) children treated by surgical procedures other than mandibular distraction, and (3) patients without preoperative and/or postoperative three-dimensional CT images.
MATERIALS During the study period, 26 patients with mandibular hypoplasia and respiratory distress were treated in our department. All patients presented apnea/hypopnea index of greater than 1 and airway obstruction at the level of the base of tongue verified by nasoendoscopy and bronchoscopy. No further alterations of the superior airway or comorbidities were present. Twenty-one (80.7%) of 26 pediatric patients were affected by isolated Pierre Robin sequence (iPRS), 3 patients (11.5%) had Crouzon syndrome, 1 patient (3.8%) had a complex craniofacial syndrome, and 1 patient (3.8%) was affected by hemifacial microsomia. Our goal was to avoid tracheostomy or, if it was present, to remove it. Eleven patients (42.3%) with respiratory distress with iPRS were successfully resolved with conservative treatment (prone position, nasopharyngeal tube, or orthodontic plate). Three patients (11.5%) affected by iPRS were treated by tongue lip adhesion within the first 10 days postnatal. As a consequence, a total of 14 patients (53.8%) receiving conservative treatment were successfully treated, thus avoiding tracheostomy. Twelve patients (46.1%) with congenital hypoplastic mandible who underwent DO met the inclusion criteria for this study. The final study sample consisted of 12 patients (4 female and 8 male patients), with a mean age of 43.3 months (range, 8–81 months). The included patients had congenital hypoplastic mandible related to iPRS (n ¼ 7), hemifacial microsomia (n ¼ 1), Crouzon syndrome (n ¼ 3), and severe complex craniofacial malformation with micrognathia and microstomia (n ¼ 1), and they were not considered candidate to tongue lip adhesion because of the presence of teething or failure of conservative treatments. All but 1 patient presented to our attention with tracheostomy performed in other hospitals and were considered candidate to DO of the mandible in order to remove or avoid tracheostomy. #
2015 Mutaz B. Habal, MD
Volume/Surface Changes of Upper Airways
Surgical Management Under general anesthesia, the angle and the body of the mandible were exposed through a bilateral submandibular approach. After mandibular osteotomies, an external fixation device was rigidly fixed to allow distraction (KLS Martin; Tuttlingen, Germany). The distractors were fixed bilaterally. Initial bone gap at the end of surgery was registered between 2 and 4 mm. The distractor was activated between the third and the fifth postoperative days; 2 distractor activations were performed per day (0.5 mm in the morning and 0.5 mm in the evening), which corresponds to a lengthening of 1 mm/ d. Active distraction was followed by a fixation period of approximately twice the number of millimeters of distraction in days to allow consolidation of the osteotomy site. Healing was uneventful in all cases. Postoperative clinical evaluation was performed. Cephalometric examinations and orthopantomography were performed weekly to assess the progress of distraction and bone formation and to check the position and effectiveness of the distractors. Threedimensional CT scan was performed before surgery and after removal of the distractors to assess the changes of the upper airway in terms of volume and surface.
Imaging Recourse: Analysis and Parameters Preoperative CT and postoperative CT were performed with the same equipment (Brilliance CT 64; Philips, Andover, MA) at the Department of Radiology of the ‘‘Children’s Hospital Meyer,’’ Florence. Computed tomographic scans were performed with 1-mm axial tomograms, with reconstructions in the coronal and sagittal planes. At the end of the distraction, three-dimensional reconstruction of the airway was performed using the software SimPlant Pro 15 (Materialize Dental, Leuven, Belgium). The upper limit was the hard palate identified by the posterior nasal spine; the lower limit has been identified by the axial slice, which visualized the fold reflection of the base of the epiglottis. The walls of the pharynx have been used as lateral and posterior boundaries. The anterior boundary is composed of the front wall of the pharynx, the base of the tongue, and the soft palate.16– 19
RESULTS The distractors were fixed at the mandibular angle (n ¼ 2), body (n ¼ 8), and ramus (n ¼ 2); mean intraoperative activation was 3.3 mm (range, 2–4 mm), and mean latency period was 3.5 days (range, 3–5 days). The average linear advancement was 17.1 mm (range, 14–25 mm). The mean consolidation period was 6.9 weeks (range, 5–12 weeks). Eleven patients (91.6%) experienced improvement of volumes and areas of the upper airway with better control of the airway.
FIGURE 1. Preoperative virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 10 months-old patient affected by Pierre Robin syndrome (patient 1).
651
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Spinelli et al
The Journal of Craniofacial Surgery
Volume 26, Number 3, May 2015
FIGURE 2. Postdistraction virtual three-dimensional computed tomography scan demonstrating soft tissue, skull, and airway reconstruction of a 20 months-old patient affected by Pierre Robin syndrome (patient 1). FIGURE 5. Preoperative virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 5-year-9-month-old patient affected by Pierre Robin syndrome (patient 8).
FIGURE 3. Preoperative virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 5 years and 2 months years-old patient affected by Crouzon syndrome (patient 3).
Tracheostomy was removed following polysomnography with an apnea/hypopnea index of less than 1 and tracheostomy plugging. Upper airway changes were further investigated with three-dimensional CT scan study in order to quantify volume and surface improvement. What we are going actually to do with this new information is a superior analysis of volume and surface area improvement of the upper airways following mandibular DO. In particular, we found out the surface improvement is not proportional to volume enhancement (89.4% vs 279.2%) (Figs. 1–8). Tracheotomy was failed to be removed from patient 5, with a complex craniofacial syndrome, because surface and volume of the upper airway decreased after distraction. We did not identify a specific reason for the low deterioration, probably to be attributed to the complexity of the syndrome with severe hypoplastic mandible. Patients’ data, including age, syndrome, tracheostomy, distraction details, and bone consolidation, are shown in Table 1. Volume and surface area increased by an average of 279.2% and 89.4%,
FIGURE 6. Postdistraction virtual three-dimensional computed tomography scan demonstrating soft tissue, skull, and airway reconstruction of a 6-year7-month-old patient affected by Pierre Robin syndrome (patient 8).
FIGURE 4. Postdistraction virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 5-year-9month-old patient affected by Crouzon syndrome (patient 3).
FIGURE 7. Preoperative virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 3-year-2-month-old patient affected by Crouzon syndrome (patient 7).
652
respectively (Tables 2 and 3). We did not record complications such as device failures, scarring, pin loosening/infection, premature bone consolidation, nerve or tooth buds injuries, joint ankylosis, or pneumonitis.
DISCUSSION Analysis of clinical and radiological results of DO shows that 2 patients did not need any further treatment. Of the 3 patients with a tracheotomy before mandibular distraction, 1 patient has been successfully decannulated after distraction, and 2 were no longer tracheotomy dependent and had their tracheotomies capped. Only 1 case failed, resulting in a reduction of the volume and the
#
2015 Mutaz B. Habal, MD
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Volume 26, Number 3, May 2015
Volume/Surface Changes of Upper Airways
TABLE 2. Airway Volume Changes Following Mandibular DO
Case 1 2 3 4 5
FIGURE 8. Postdistraction virtual three-dimensional computed tomography scan demonstrating soft tissue, skull, and airway reconstruction of a 4-year11-month-old patient affected by Crouzon syndrome (patient 7).
respiratory surface area. This is likely to be related to the extreme complexity of the malformation that affects the patient: an extremely severe grade of microstomia associated with mandibular hypoplasia. Our study demonstrates that after DO in patients with congenital mandibular hypoplasia, the upper airway undergoes an increase in size, in terms of volume and surface area. In the majority of patients, changes of the airway have been accompanied by improvements of sleeping and breathing, allowing for the removal of the tracheotomy tube, and/or resulting in the alleviation of symptoms. If, after normalization of the anatomy of the upper airway, poor oxygenation and/or apnea persist, other causes of respiratory dysfunction should be taken into consideration. Analysis of the results also provides us with important data to understand the relationship between the response times and the benefit of the procedures performed to increase the space of the airways. According to the literature, patients are placed into 2 groups: those who received the intervention of the airway early (within the first 3 months of life) and those who received it late (after 3 months of life). Studies have shown that patients with iPRS operated early have excellent results with a success rate of approximately 100%. Patients affected by iPRS who are treated after 3 months of age demonstrate less chance of success (approximately 87%). Conversely, patients with syndromic PRS show lower chance of success after treatment ranging from 12.5% (
Three-Dimensional Airways Reconstruction in Syndromic Pedriatric Patients Following Mandibular Distraction Osteogenesis Giuseppe Spinelli, MD, DDS, Tommaso Agostini, MD, Francesco Arcuri, MD, Marco Conti, MD, and Mirco Raffaini, MD, PhD Background: Airway obstruction, associated with mandibular hypoplasia, is a frequent complication in syndromic pediatric patients. The clinical signs of airway obstruction change from mild positional obstruction to severe respiratory distress with cyanosis. The young age of the patients makes medical management extremely complex. Methods: The purpose was to evaluate the success of surgery, evaluating the expansion of the respiratory volumes measured by computer tomography analyzed through a software (SimPlant Pro 15). Twelve patients with mandibular hypoplasia and respiratory distress were treated between December 2010 and December 2013. Eleven of them had tracheostomy in the preoperative period. The goal of surgery was to prevent permanent tracheostomy or to remove it, if present. Results: Volume and surface area increased by an average of 279.2% and 89.4%, respectively. Tracheostomy was avoided in 1 patient who underwent surgery precociously, and it was removed in 10 patients. Only 1 case failed in volume airway augmentation, and tracheostomy was not removed. Conclusions: Computer tomography can calculate the cross-sectional areas of the airway in 3 planes of space: coronal, sagittal, and axial. In most patients, changes in airways have been accompanied by improvements in sleep and breathing, allowing for the removal of tracheostomy with an improved quality of life. Three-dimensional reconstruction of airways revealed a useful tool to better understand the success of surgery. Level of evidence: IV. Key Words: Distraction osteogenesis, syndromic patients, respiratory distress, three-dimensional CT scan, tracheostomy (J Craniofac Surg 2015;26: 650–654)
M
anagement of airway obstruction associated with mandibular hypoplasia is a challenging condition in pediatric patients affected by severe craniofacial malformations such as Pierre Robin sequence or Stickler syndrome, Crouzon syndrome, Treacher From the Department of Maxillo-Facial Surgery, CTO-AOUC, University of Florence, Florence, Italy. Received June 21, 2014. Accepted for publication October 28, 2014. Address correspondence and reprint requests to Tommaso Agostini, MD, Department of Maxillo-Facial Surgery, University of Florence, Largo Palagi 1, Florence, Italy; E-mail: [email protected] The authors report no conflict of interest. Copyright # 2015 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001421
650
Collins syndrome, Goldenhar syndrome, Freeman-Sheldon syndrome, Nager syndrome, or other diseases that include mandibular hypoplasia. Clinical signs of airway obstruction change from mild positional obstruction to severe life-threatening respiratory distress with cyanosis. Perinatal airway obstruction varies in severity from mild, moderate, to severe, with risk of complete obstruction and mortality from cor pulmonale due to respiratory failure. Because of the frequent concomitant cleft palate, these pediatric patients can demonstrate feeding difficulties, which can require specialized nipples, obturators, or nasogastric tubes.1– 4 Management of respiratory distress can be both medical and surgical. Depending on the degree of severity, different conservative options have been described to correct the obstructed airway in the neonatal period of syndromic pediatric patients with hypoplastic mandible. Mild airway obstruction can be managed by positional therapy (prone or lateral position) with neck extension or by continuous positive airway pressure. In the moderate cases, nasal stents with a small-diameter endotracheal tube can be used to prevent glossoptosis and consequent obstruction of the posterior pharyngeal wall. For moderate to severe airway obstruction, a surgical treatment is mandatory.5 –8 With regard to invasive procedures, tracheotomy, tongue lip adhesion, and mandibular distraction osteogenesis (DO) are commonly performed and widely accepted. For the severely compromised airway obstruction, tracheostomy immediately solves the problem. However, this surgical solution is frequently characterized by perioperative (hypotension, cardiac arrhythmias, pneumothorax, bleeding, peritracheal insertion) and postoperative complications/sequelae (tube occlusion/ displacement, vocal cord paralysis, tracheoesophageal fistula, subcutaneous emphysema, scarring and granuloma formation, tracheomalacia, tracheal stenosis).9,10 Tongue lip adhesion was first described by Douglas11,12 in 1946, and it was characterized by an extremely low success rate. After that, Denny13 has shown the unpredictable results of this procedure. He reported an 18% success rate; the majority of the patients required further procedure to solve the airway or feeding problems.11–13 Finally, since the 1990 s, DO has been successfully used to control the airway obstruction in pediatric patients affected by severe craniofacial malformations with congenital hypoplastic mandible. Distraction osteogenesis enlarges the pharyngeal region by lengthening the mandible and advancing the base of the tongue off the posterior pharyngeal wall. Tracheotomy can be avoided, or if present, it can be removed during or after mandibular distraction. Although the excellent results of DO applied to patients affected by mandibular hypoplasia and airway obstruction localized in the pharyngeal region above the level of the vocal cords, several complications are described such as device failures, scarring, pin loosening/infection, premature bone consolidation, nerve or tooth buds injuries, joint ankylosis, pneumonitis, and failure to decannulate the tracheostomy or control the airway obstruction.14,15 Congenital hypoplastic mandible is frequently associated with an
The Journal of Craniofacial Surgery
Volume 26, Number 3, May 2015
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Volume 26, Number 3, May 2015
abnormal upper airway and an increased collapse of the pharynx leading to obstructive sleep apnea. Mandibular distraction improves breathing and oxygenation by lengthening the mandible and normalizing the upper airway in terms of size and shape. Pediatric and adult normal values for 16 parameters of the size and shape of the upper airway have been recently described.16–19
STUDY DESIGN The purpose of this retrospective study was to evaluate the postoperative three-dimensional changes of the upper airway of pediatric patients after DO in terms of size and shape. The aims were to evaluate the areas and the volumes of the airway anatomy with a three-dimensional computed tomographic (CT) analysis and to compare the preoperative and postoperative results in children with syndromic hypoplastic mandible and obstructive sleep apnea, who received DO. The hypothesis was that mandibular distraction would increase the airway size and would change the airway shape with a better control of the obstructive sleep apnea. To address this hypothesis, we enrolled a cohort of pediatric patients with hypoplastic mandible who received mandibular DO. Medical records and radiological findings of 26 patients with mandibular hypoplasia and respiratory distress treated in the period between December 2010 and December 2013 were reviewed. All patients presented an apnea/hypopnea index of greater than 1 and obstruction of the base of tongue evaluated by nasoendoscopy and bronchoscopy. Inclusion criteria were (1) syndromic hypoplastic mandible, (2) mandibular advancement by DO, and (3) preoperative and postoperative three-dimensional CT images. Exclusion criteria were (1) children without hypoplastic mandible, (2) children treated by surgical procedures other than mandibular distraction, and (3) patients without preoperative and/or postoperative three-dimensional CT images.
MATERIALS During the study period, 26 patients with mandibular hypoplasia and respiratory distress were treated in our department. All patients presented apnea/hypopnea index of greater than 1 and airway obstruction at the level of the base of tongue verified by nasoendoscopy and bronchoscopy. No further alterations of the superior airway or comorbidities were present. Twenty-one (80.7%) of 26 pediatric patients were affected by isolated Pierre Robin sequence (iPRS), 3 patients (11.5%) had Crouzon syndrome, 1 patient (3.8%) had a complex craniofacial syndrome, and 1 patient (3.8%) was affected by hemifacial microsomia. Our goal was to avoid tracheostomy or, if it was present, to remove it. Eleven patients (42.3%) with respiratory distress with iPRS were successfully resolved with conservative treatment (prone position, nasopharyngeal tube, or orthodontic plate). Three patients (11.5%) affected by iPRS were treated by tongue lip adhesion within the first 10 days postnatal. As a consequence, a total of 14 patients (53.8%) receiving conservative treatment were successfully treated, thus avoiding tracheostomy. Twelve patients (46.1%) with congenital hypoplastic mandible who underwent DO met the inclusion criteria for this study. The final study sample consisted of 12 patients (4 female and 8 male patients), with a mean age of 43.3 months (range, 8–81 months). The included patients had congenital hypoplastic mandible related to iPRS (n ¼ 7), hemifacial microsomia (n ¼ 1), Crouzon syndrome (n ¼ 3), and severe complex craniofacial malformation with micrognathia and microstomia (n ¼ 1), and they were not considered candidate to tongue lip adhesion because of the presence of teething or failure of conservative treatments. All but 1 patient presented to our attention with tracheostomy performed in other hospitals and were considered candidate to DO of the mandible in order to remove or avoid tracheostomy. #
2015 Mutaz B. Habal, MD
Volume/Surface Changes of Upper Airways
Surgical Management Under general anesthesia, the angle and the body of the mandible were exposed through a bilateral submandibular approach. After mandibular osteotomies, an external fixation device was rigidly fixed to allow distraction (KLS Martin; Tuttlingen, Germany). The distractors were fixed bilaterally. Initial bone gap at the end of surgery was registered between 2 and 4 mm. The distractor was activated between the third and the fifth postoperative days; 2 distractor activations were performed per day (0.5 mm in the morning and 0.5 mm in the evening), which corresponds to a lengthening of 1 mm/ d. Active distraction was followed by a fixation period of approximately twice the number of millimeters of distraction in days to allow consolidation of the osteotomy site. Healing was uneventful in all cases. Postoperative clinical evaluation was performed. Cephalometric examinations and orthopantomography were performed weekly to assess the progress of distraction and bone formation and to check the position and effectiveness of the distractors. Threedimensional CT scan was performed before surgery and after removal of the distractors to assess the changes of the upper airway in terms of volume and surface.
Imaging Recourse: Analysis and Parameters Preoperative CT and postoperative CT were performed with the same equipment (Brilliance CT 64; Philips, Andover, MA) at the Department of Radiology of the ‘‘Children’s Hospital Meyer,’’ Florence. Computed tomographic scans were performed with 1-mm axial tomograms, with reconstructions in the coronal and sagittal planes. At the end of the distraction, three-dimensional reconstruction of the airway was performed using the software SimPlant Pro 15 (Materialize Dental, Leuven, Belgium). The upper limit was the hard palate identified by the posterior nasal spine; the lower limit has been identified by the axial slice, which visualized the fold reflection of the base of the epiglottis. The walls of the pharynx have been used as lateral and posterior boundaries. The anterior boundary is composed of the front wall of the pharynx, the base of the tongue, and the soft palate.16– 19
RESULTS The distractors were fixed at the mandibular angle (n ¼ 2), body (n ¼ 8), and ramus (n ¼ 2); mean intraoperative activation was 3.3 mm (range, 2–4 mm), and mean latency period was 3.5 days (range, 3–5 days). The average linear advancement was 17.1 mm (range, 14–25 mm). The mean consolidation period was 6.9 weeks (range, 5–12 weeks). Eleven patients (91.6%) experienced improvement of volumes and areas of the upper airway with better control of the airway.
FIGURE 1. Preoperative virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 10 months-old patient affected by Pierre Robin syndrome (patient 1).
651
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Spinelli et al
The Journal of Craniofacial Surgery
Volume 26, Number 3, May 2015
FIGURE 2. Postdistraction virtual three-dimensional computed tomography scan demonstrating soft tissue, skull, and airway reconstruction of a 20 months-old patient affected by Pierre Robin syndrome (patient 1). FIGURE 5. Preoperative virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 5-year-9-month-old patient affected by Pierre Robin syndrome (patient 8).
FIGURE 3. Preoperative virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 5 years and 2 months years-old patient affected by Crouzon syndrome (patient 3).
Tracheostomy was removed following polysomnography with an apnea/hypopnea index of less than 1 and tracheostomy plugging. Upper airway changes were further investigated with three-dimensional CT scan study in order to quantify volume and surface improvement. What we are going actually to do with this new information is a superior analysis of volume and surface area improvement of the upper airways following mandibular DO. In particular, we found out the surface improvement is not proportional to volume enhancement (89.4% vs 279.2%) (Figs. 1–8). Tracheotomy was failed to be removed from patient 5, with a complex craniofacial syndrome, because surface and volume of the upper airway decreased after distraction. We did not identify a specific reason for the low deterioration, probably to be attributed to the complexity of the syndrome with severe hypoplastic mandible. Patients’ data, including age, syndrome, tracheostomy, distraction details, and bone consolidation, are shown in Table 1. Volume and surface area increased by an average of 279.2% and 89.4%,
FIGURE 6. Postdistraction virtual three-dimensional computed tomography scan demonstrating soft tissue, skull, and airway reconstruction of a 6-year7-month-old patient affected by Pierre Robin syndrome (patient 8).
FIGURE 4. Postdistraction virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 5-year-9month-old patient affected by Crouzon syndrome (patient 3).
FIGURE 7. Preoperative virtual three-dimensional computed tomography scan showing soft tissue, skull, and airway reconstruction of a 3-year-2-month-old patient affected by Crouzon syndrome (patient 7).
652
respectively (Tables 2 and 3). We did not record complications such as device failures, scarring, pin loosening/infection, premature bone consolidation, nerve or tooth buds injuries, joint ankylosis, or pneumonitis.
DISCUSSION Analysis of clinical and radiological results of DO shows that 2 patients did not need any further treatment. Of the 3 patients with a tracheotomy before mandibular distraction, 1 patient has been successfully decannulated after distraction, and 2 were no longer tracheotomy dependent and had their tracheotomies capped. Only 1 case failed, resulting in a reduction of the volume and the
#
2015 Mutaz B. Habal, MD
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Volume 26, Number 3, May 2015
Volume/Surface Changes of Upper Airways
TABLE 2. Airway Volume Changes Following Mandibular DO
Case 1 2 3 4 5
FIGURE 8. Postdistraction virtual three-dimensional computed tomography scan demonstrating soft tissue, skull, and airway reconstruction of a 4-year11-month-old patient affected by Crouzon syndrome (patient 7).
respiratory surface area. This is likely to be related to the extreme complexity of the malformation that affects the patient: an extremely severe grade of microstomia associated with mandibular hypoplasia. Our study demonstrates that after DO in patients with congenital mandibular hypoplasia, the upper airway undergoes an increase in size, in terms of volume and surface area. In the majority of patients, changes of the airway have been accompanied by improvements of sleeping and breathing, allowing for the removal of the tracheotomy tube, and/or resulting in the alleviation of symptoms. If, after normalization of the anatomy of the upper airway, poor oxygenation and/or apnea persist, other causes of respiratory dysfunction should be taken into consideration. Analysis of the results also provides us with important data to understand the relationship between the response times and the benefit of the procedures performed to increase the space of the airways. According to the literature, patients are placed into 2 groups: those who received the intervention of the airway early (within the first 3 months of life) and those who received it late (after 3 months of life). Studies have shown that patients with iPRS operated early have excellent results with a success rate of approximately 100%. Patients affected by iPRS who are treated after 3 months of age demonstrate less chance of success (approximately 87%). Conversely, patients with syndromic PRS show lower chance of success after treatment ranging from 12.5% (
