2015 HSC Section 1 Book of Articles

Research Original Investigation

Mandibular Distraction Osteogenesis

3.4 [95%CI, 1.4-8.4]) comparedwith patients with 0 or 1 other procedure. In a multivariable regression model adjusting for all these variables, only length of follow-up (OR, 1.2 [95% CI, 1.0-1.3]) and number of other airway procedures (OR, 3.2 [95% CI, 1.2-8.6]) remained significantly associated with occur- rence of a complication. Figure 2 demonstrates the modeled probabilities of a complication withMDO in the 2 initial treat- ment subgroups as a function of these 2 independent predic- tors. One can see that in both theMDO-first subgroup and the tracheotomy-first subgroup, the probability of a complica- tion increases with length of follow-up time. In addition, for any given follow-up duration, there is a greater probability of a complication when 2 or more other airway procedures are required.

Discussion The application of distraction osteogenesis to themandible for the treatment of symptomatic micrognathia was first de- scribed by McCarthy et al 16 in 1992, and since that time there have been increasing reports of the outcomes of this interven- tion in the pediatric population. Owing to the heterogeneous nature of the patient population that experiences sympto- matic micrognathia severe enough to warrant surgical inter- vention, definitions of success have varied depending on the specific study. Given this context, success rates forMDO in im- proving or relieving airway obstruction due to micrognathia have been reported to range from 63% to 100% depending on the definition of success used. 8-11,17-20 In a recent meta- analysis, Ow and Cheung 19 found a 91% rate of prevention of tracheotomy among neonates undergoing MDO as an initial procedure and a 78% rate of decannulation among patients with existing tracheostomies who underwent MDO. This study reports the outcomes ofMDO in one of the larg- est cohorts of patients treated for symptomatic micrognathia. The relatively large cohort provided greater statistical power thanmost previous reports and facilitated the investigation of potential predictorsof surgical success andcomplications.Over- all, we found a high rate of surgical success among patients undergoingMDO, especially among those undergoingMDO as an initial procedure to treat symptomatic micrognathia. The

Table 3. Adjusted Associations Between Potential Predictors and Surgical Success in the Tracheotomy-First Subgroup Variable OR (95% CI)

P Value

Male

0.31 (0.09-1.10)

.07

Diagnosis a Treacher-Collins syndrome CFM–Goldenhar syndrome

0.45 (0.06-3.60) 0.05 (0.005-0.43) 0.27 (0.06-1.20) 1.15 (0.93-1.40)

.45

.007

Other

.09 .20

Age at distraction, y

Abbreviation: CFM, craniofacial microsomia. a Reference diagnosis was isolated Pierre Robin sequence.

Figure 1. Predicted Probabilities for Surgical Success (Tracheotomy-First Subgroup)

Females

Males

A

B

1.0

1.0

0.8

0.8

0.6

0.6

0.4

0.4

Probability of Surgical Success

Probability of Surgical Success

Diagnosis

0.2

0.2

Isolated Pierre Robin sequence Treacher-Collins syndrome

Goldenhar syndrome or craniofacial microsomia Other

0.0

0.0

0

5

10

15

20

0

5

10

15

20

Age, y

Age, y

Predicted probabilities of surgical success among patients who had a tracheotomy prior to mandibular distraction osteogenesis. A, Females; B, males. The colored dotted lines indicate differences in the probability of success for each diagnosis. Open circles represent the observed values.

JAMA Otolaryngology–Head & Neck Surgery April 2014 Volume 140, Number 4

jamaotolaryngology.com

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