Arlen D. Denny

Mandibular distraction osteogenesis in very young patients to correct airway obstruction

The purpose of this study was to measure changes in the airway cross‐sectional area of pediatric patients with micrognathia and obstructive airway symptoms after treatment by mandibular distraction. The measurements obtained were correlated with the clinical outcomes. Ten patients, ranging in age from 3 months to 8 years, underwent measurement and distraction. Eight patients were under 30 months of age. Six were diagnosed with Pierre Robin sequence, two with Treacher Collins syndrome, and two with Nager syndrome. All patients had retrognathia of greater than 8 mm and obstructive airway symptoms while awake that had resulted in tracheostomy (3), repeated apnea monitor triggering (5), or abnormal sleep study (2). Cephalometric analysis was performed pretreatment and posttreatment by distraction. The effective airway space was defined with the following boundaries: a horizontal line from the tip of the odontoid to the velum, the uvula tip to the tongue base along the shortest line, the tongue base down to the base of the epiglottis, and the horizontal line to the posterior pharynx. These lines were traced for each cephalogram, the outline was digitized, and the area was calculated by computer. An analysis of the square area change was done by paired t test. The range of distraction was 8 to 22 mm; the mean effective airway increase was 67.5 percent, with a range of 26 to 120 percent. Measurable airway increase occurred in all patients who underwent distraction, and all patients showed clinical improvement. Six patients with Pierre Robin sequence became asymptomatic, with normal sleep, feeding, and weight gain. Two patients with Nager syndrome and tracheostomies were decannulated and were asymptomatic postdistraction. One patient with Treacher Collins syndrome without tracheostomy became asymptomatic after mandibular distraction; one patient failed to distract because of premature consolidation and continued to require a cannula. Mandibular distraction seems to provide a consistent change in tongue base position that improves obstructive airway symptoms by increasing measured effective airway space. The potential for mandibular distraction exceeds the simple correction of malocclusion also by eliminating soft‐tissue obstruction of the micrognathic airway. Airway improvement is independent of the syndrome diagnosed. Mandibular distraction osteogenesis may be useful to avoid or decannulate existing tracheostomy in infants with micrognathia. (Plast. Reconstr. Surg. 108: 302, 2001.)

Mandibular distraction in neonates: a strategy to avoid tracheostomy.

&NA; Over the past 5 years, the authors developed an application of mandibular distraction osteogenesis to eliminate existing tracheostomy. That experience led the authors to attempt mandibular distraction osteogenesis in neonates as an alternative before tracheostomy. Success with this approach using supporting objective airway measurements has been reported previously. This report includes six neonates diagnosed with Pierre Robin sequence. Of the six, five neonates ranging in age from 6 to 26 days (mean, 14.5 days) were treated by the authors with mandibular distraction over a 22‐month period. The sixth neonate was treated with tracheostomy, because of other airway abnormalities. Findings included retrognathia, glossoptosis, incomplete cleft palate, and airway obstruction in each patient. Birth weights ranged from 2.8 to 3.2 kg. All patients were unable to control their airway during feeding, as evidenced by repeated episodes of choking and obstruction. Resting oxygen saturations were in the 70 to 80 percent range in all patients, with further deterioration during attempted feeding. Bronchoscopy was performed in all patients under anesthesia before distraction. Recurrent near‐complete and intermittent complete airway obstruction were present in all patients at the level of the tongue base. There was a consensus by a pediatric intensivist, a pediatric anesthesiologist, and a pediatric otolaryngologist in all cases. Each patient met all criteria requiring ventilation for life support. Tracheostomy would be required if mandibular distraction osteogenesis was not performed, or if it failed. Patients with other airway abnormalities were not considered for treatment. Maxillomandibular disharmony measured at the midline ranged from 8 to 15 mm (mean, 11.2 mm). Active distraction was performed at the rate of 1 to 2 mm a day, with a consolidation period of 4 weeks. Total time of treatment was less than 6 weeks in all cases. All patients were extubated by the completion of active distraction. Distraction distance ranged from 8 to 15 mm (mean, 12.4 mm). All patients were discharged to home on apnea monitors, the use of which was discontinued after 90 days with no further apneic events. Weight gains met or exceeded the average 500 g a month after distraction. Bronchoscopy at the time of distractor removal showed correction of airway obstruction at the tongue base. Radiographs showed bilateral ossification of the distraction sites. Tracheostomy was avoided in all cases selected for treatment by distraction. Patient follow‐up range was 9 to 22 months. In selected Pierre Robin sequence patients with tongue base airway obstruction, mandibular distraction osteogenesis can successfully avoid the need for and the associated mortality and morbidity of indwelling tracheostomy. (Plast. Reconstr. Surg. 109: 896, 2002.)

Outcomes of tongue-lip adhesion for neonatal respiratory distress caused by Pierre Robin sequence.

Tongue-lip adhesion can be effective in relieving tongue-based airway obstruction in the neonatal period. However, longitudinal evaluation of these patients demonstrates they require additional procedures for ultimate control of their airway, feeding, and orthognathic relationship. Charts of patients with Pierre Robin sequence who underwent unsuccessful nonoperative treatment and tongue-lip adhesion procedures by the senior author between 1989 to 1999 were reviewed. In particular, secondary interventions were quantified and qualified to determine if tongue-lip adhesion was a definitive treatment of the pathology caused by this sequence. Eleven patients with ages ranging from 2 to 6 weeks underwent initial tongue-lip adhesion. Seven patients were syndromic (3 Stickler’s, 1 Goldenhar’s, 1 Fragile X, 1 Miller’s, 1 chromosome 15 rearrangement), and four had isolated Pierre Robin sequence. Two patients had dehiscence of their initial repair within 2 weeks, for a primary surgical success rate of 82%, consistent with other published reports. A detailed follow-up of these patients revealed that 10 of 11 (91%) required additional intervention for airway or feeding issues. Of those requiring secondary intervention, an additional 1.9 secondary procedures were performed per patient to achieve control of the airway, feeding, and orthognathic problems. More than half of the patients needed gastrostomy tubes to overcome feeding difficulties. Five patients necessitated secondary surgery for recurrent airway obstruction within 4 months of the initial surgical treatment (four distractions and one repeat tongue-lip adhesion). Four others required distraction at an older age for orthognathic indications. Two patients were successfully treated with tongue-lip adhesion only. Tongue-lip adhesion has a high initial success rate for correction of neonatal airway obstruction. However, long-term follow-up indicates a high incidence of secondary intervention requirements. In retrospect, perhaps tongue-lip adhesion should be considered a temporizing procedure for most patients with Pierre Robin sequence.

Distraction osteogenesis in Pierre Robin neonates with airway obstruction

Mandibular distraction osteogenesis can be a safe and effective way to avoid tracheostomy placement in selected neonates with Pierre Robin sequence,with or without other associated syndromes. In non-syndromic Pierre Robin sequence syndromes, this procedure, in the current authors experience, has provided definitive correction of both airway obstruction and micrognathia. The cost to patients and families appropriately treated by mandibular distraction osteogenesis is substantially less than tracheostomy. Mandibular distraction does not involve the ongoing maintenance, medical care, and high risk of mortality associated with tracheostomy. A support team of pediatric anesthesia, pulmonary, and otolaryngology specialists is required for the safe and successful selection and treatment of this group of patients with Pierre Robin sequence using mandibular distraction. The authors investigation of this group is ongoing.

Rotation advancement of the midface by distraction osteogenesis.

&NA; A wide variety of disease processes produce alteration of midfacial skeletal growth, resulting in moderate‐to‐severe midface deficiency presenting as retrusion associated with Angles class III malocclusion. Le Fort III osteotomies with advancement can provide an excellent tool for correction of this deformity. Recently, the corrective procedure of choice for advancement of midfacial segments has been distraction osteogenesis after osteotomy. Straight linear advancement is the most common choice for corrective movement of the midfacial segment, whether accomplished through acute surgical advancement or through the progressive distraction technique. Unfortunately, linear advancement can produce abnormal configurations, both at the nasal root and lateral orbits, regardless of the technique used. Enophthalmos, caused by orbital enlargement, may limit the advancement necessary to achieve class I occlusion. The authors have extended the utility of the Le Fort III procedure and have improved the final outcome by creating a controlled rotation advancement of the midfacial segment using distraction. The application of an existing internal distraction device is modified to control the movement of the midfacial segment in a rotation advancement path. Included in the series were 10 patients with severe midface retrusion secondary to multiple congenital syndromes, along with cleft lip and palate. The ages of the patients ranged from 6 to 14 years. An internal distraction system was used in all cases. Application of the distractor was substantially modified to simplify both fixation and removal and to produce controlled rotation advancement. The team orthodontist determined the final occlusal relationship. Percutaneous distractor drive rods were removed 4 to 6 weeks after active distraction to increase patient comfort. The distractors and all associated hardware were removed after 12 to 16 weeks of consolidation; follow‐up periods ranged from 1 to 3 years. By using the modified distractor application to produce rotation advancement, the contour abnormalities at the nasal root and lateral orbit and the enophthalmos produced by linear advancement were eliminated. Significant improvement in facial contour and class I occlusion was obtained in all cases. Complications consisted of near exposure of the device in one patient. Stability has been excellent, with no relapse reported by the orthodontist. Rotational advancement of facial segments by distraction allows successful early intervention in patients with significant midface retrusion. The abnormal nasal root and lateral orbital configurations produced by direct linear advancement are avoided, and a stable and normalized facial configuration is produced. (Plast. Reconstr. Surg. 111: 1789, 2003.)

Secondary Alveolar Bone Grafting Using Milled Cranial Bone Graft: A Retrospective Study of a Consecutive Series of 100 Patients

OBJECTIVE The purpose of this study was to evaluate the outcome of secondary bone grafting of alveolar clefts using milled cranial bone graft. PATIENTS The study included a consecutive series of 100 patients who were operated on between 1986 and 1995 by a single senior surgeon. MEASUREMENTS The patients were divided into four groups; (1) unilateral alveolar cleft or (2) bilateral alveolar cleft, (3) before eruption of the canine teeth or (4) after eruption. Follow-up ranged from a minimum of 12 months to 10 years, and evaluation included a physical examination, medical photography, orthodontic reports, and a panorex X-ray and/or a three-dimensional computed tomography scan of the maxilla produced using Denta-scan software. Patient outcomes were judged to be good, acceptable, or poor. Patients who developed any fistula or required regrafting were defined as poor outcomes. RESULTS The combined good and acceptable outcomes represented 83% of the entire consecutive series. These two groups were defined as successful outcomes. In patients with unilateral and bilateral clefts who were under 12 years old, the success rate was 90% and 88%, respectively. In patients grafted following full canine eruption (>12 years old), success rate decreased to 83% in patients with unilateral and 66% in bilateral clefts, respectively. CONCLUSIONS Our results support the use of milled cranial bone graft, which produces a stable closure of the alveolar cleft with good contour and support for adjacent tooth eruption. Our data further support the conclusion by others that outcomes of early secondary grafting are superior to delayed grafting. The experience presented here, including the success rate, ease of harvesting, and minimal morbidity, makes the cranium our preferred donor site for alveolar cleft grafting.

Frontofacial Osteotomies, Advancement, and Remodeling by Distraction; An Extended Application of the Technique

The purpose of this clinical report is to present the distraction technique for advancement of the frontofacial skeleton as a unit. Our 14-year-old patient was diagnosed with Carpenters syndrome and kleblattschädel deformity at birth. At other centers the patient underwent corrective surgeries, including repeated fronto-orbital advancement in an attempt to correct the residual deformity. This has resulted in bony malunion and recurrent deformity, and it has left the patient with no available donor sites for harvesting of bone graft. The patient had class III malocclusion, severe midfacial and frontal deficiency, and relative turricephaly. We performed frontofacial osteotomies and placement of the distraction devices. Distraction of 20 mm was accomplished, correcting the exophthalmos and midface retrusion and producing class I dental occlusion. We conclude that distraction is an optional surgical method that can be applied in selected cases for advancement of the entire frontofacial skeleton.

Correction of sagittal synostosis using foreshortening and lateral expansion of the cranium activated by gravity: surgical technique and postoperative evolution.

Background: The authors present a technique for correction of sagittal synostosis addressing the transverse constriction and providing foreshortening of the skull without the use of hardware. The design of the osteotomies combined with strict postoperative supine positioning allows foreshortening of the skull, with concomitant expansion. Methods: Twenty-two patients were operated on using the foreshortening and lateral expansion activated by gravity technique. Postoperative follow-up included clinical evaluation and three-dimensional computed tomographic scanning at 4 to 6 weeks, 1 year, and yearly afterward. These scans were analyzed using three-dimensional surface analysis software, according to a protocol the authors describe in this article. Results: The cephalic index improved from 66.4 preoperatively to 74.5 at 1 year postoperatively (normal, 72 to 87). Transverse growth continued to be the dominant vector of growth up to 1 year (until ossification-bridging of the vertex craniectomy). Beyond 1 year, the main area of transverse growth was overlying the temporal suture, producing a distinctive temporal bossing in patients. The parietal areas showed mini-mal growth afterward. Growth was mainly occipital between 1 and 3 years of age, and frontal afterward, up to 5 years of age. A low frontal bossing also occurred in some of our patients and resolved spontaneously. Conclusions: The authors have described a technique for correction of scaphocephaly that avoids the use of hardware, with acceptable operative times and transfusion needs. Postoperative improvement in shape is satisfactory. Analysis of the three-dimensional scans of these patients shows abnormal skull growth patterns up to 5 years of age.

role of Three-dimensional Computed Tomography in the Assessment of Nasoorbitoethmoidal Fractures

&NA; Successful management of nasoorbitoethmoidal (NOE) fractures requires early diagnosis and accurate determination of the extent of injury. Although the anatomic complexity of the NOE region merits a clear interpretation of the spatial relationships associated with each injury, the role of three‐dimensional (3D) computed tomography (CT) in the assessment of these fractures remains unclear. To clarify the diagnostic value of 3D CT, this retrospective analysis compares statistically the accuracy of twodimensional (2D) CT against 3D CT in the detection of NOE fracture line tracts in 21 consecutive patients with surgically confirmed NOE fractures. Accuracy of radiographic findings of both modalities were compared with intraoperative findings serving as the “gold standard” for detecting fracture lines in NOE fractures. This statistical analysis indicates that combining 3D CT and 2D CT produces a higher diagnostic yield in the evaluation of NOE fractures than using either modality alone. Although 2D CT was significantly superior (p < 0.05) for inspection of the medial orbital wall, 3D CT offered significantly greater diagnostic accuracy (p < 0.05) along the medial maxillary buttress, particularly at the piriform aperture. 3D CT clarified spatially several unusual NOE injuries that were indiscernible with 2D CT alone. We recommend the combination of 3D CT with 2D CT for serious NOE injuries, particularly those involving displacement of the NOE complex or associated with other major midfacial fractures.

Diagnostic Pediatric Computed Tomographic Scans of the Head: Actual Dosage versus Estimated Risk

Background: Recent publications have implicated computed tomographic scans in the genesis of cancer and developmental delay. To determine whether the imaging protocols used in the authors’ craniofacial practice could be harmful, they reviewed patient radiation exposure data for 77 patients. They then reviewed the literature concerning the documented effects of low linear energy transfer received during radiation and the application of the linear no-threshold hypothesis. Methods: This is a retrospective single-institution analysis of the senior surgeon’s (A.D.) patients who underwent computed tomographic scanning of the head and face. Patient data from the years 2001 through the first half of 2008 were reviewed and the authors evaluated those who had radiation dose reports for each computed tomographic examination. Results: Newly diagnosed craniosynostosis patients underwent an average of 1.74 computed tomographic scans per year at an average dose of approximately 1.39 mSv. Syndromic patients had a higher total number of studies when compared with nonsyndromic patients (9.73 versus 4.11). In comparison with published data, the level of radiation received by the authors’ patients for computed tomographic scans of the head was 100 to 1000 times less than those levels shown to increase carcinogenesis, and nearly 40 times less than that shown to purportedly affect development and cognition. Conclusions: The authors suggest that published experimental evidence does not support the linear no-threshold model at low linear energy transfer levels similar to the exposure of their patients undergoing computed tomographic scans of the head. In addition, no convincing epidemiologic data exist demonstrating an increase in cancer incidence for doses below 100 mSv.