2015 HSC Section 1 Book of Articles

Original Investigation Research

Mandibular Distraction Osteogenesis

Table 2. Unadjusted Associations Between Potential Predictors and Surgical Success, Stratified by Initial Treatment Group

Tracheotomy First (n = 62)

MDO First (n = 61)

P Value

P Value

OR (95% CI)

OR (95% CI)

Variable

Male

0.43 (0.14-1.30)

.14

1.30 (0.34-5.10)

.69

Diagnosis a Treacher-Collins syndrome CFM–Goldenhar syndrome

0.50 (0.07-3.70) 0.01 (0.01-0.52) 0.27 (0.06-1.10) 1.10 (0.94-1.30) 1.00 (0.89-1.20) 0.98 (0.92-1.00)

.50

0.45 (0.04-4.60) 1.70 (0.06-51.80) 0.71 (0.17-2.90) 0.94 (0.84-1.00) 0.97 (0.74-1.30) 1.00 (0.95-1.20) 3.70 (0.16-85.00) 1.20 (0.03-54.00) 0.14 (0.02-0.82)

.50 .75 .63 .26 .84 .39 .41 .91 .03

.009

Other

.08 .20 .70 .54

Age at distraction, y Follow-up length, y Distraction length, mm

Abbreviations: CFM, craniofacial microsomia; MDO, mandibular distraction osteogenesis; NA, not applicable; OR, odds ratio. a Reference diagnosis was isolated Pierre Robin sequence.

Distractions, No. 2 vs 1

3.20 (0.36-28.30)

.30

3 vs 1

NA

Other airway procedures, ≥2 vs <2

0.83 (0.27-2.60)

.75

probability of surgical success (OR, 0.07 [95% CI, 0.009- 0.52]) compared with patients with isolated Pierre Robin se- quence ( Table 3 ). To better illustrate the impact of these dif- ferent variables on the probability of surgical success, Figure 1 shows the modeled probabilities of success as a function of age and syndrome diagnosis, stratified by sex. For both male and female patients, at any given age, the probability of surgical success is significantly worse for patients with CFM–Goldenhar syndrome compared with any other syn- dromic diagnosis. In contrast, patients with isolated Pierre Robin sequence have the greatest probability of success. For example, a 10-year-oldgirlwithGoldenhar syndromewhowent through a tracheotomy before MDO has a 60% probability of surgical success. For all patients, the probability of success seems to increase with greater age at the time of distraction. In the MDO-first subgroup, the only variable associated with surgical success in univariable regression analysis was number of other airway surgical procedures ( Table 4 ). Thus, multivariable regression analysis was not performed in this subgroup. In the univariable regression model, patients who had undergone fewer than 2 airway procedures had 7 times greater odds of success compared with those requiring more than 2 procedures. Among the 10 patients who required a tra- cheotomy after an initial MDO, airway pathology contribut- ing to failure of initial MDO in these patients included persis- tent glossoptosis or lingual tonsil hypertrophy (8 patients), tracheal stenosis (2), and choanal atresia (1). Five of 10 were subsequently successfully decannulated, but all required additional procedures to achieve decannulation, including lingual tonsillectomy and/or base of tongue reduction (3 patients), endoscopic suprastomal granulation tissue re- moval (2), LeFort I bimaxillary advancement (3), or choanal atresia repair (1). When we examined potential predictors of a complica- tion, univariable regression analysis demonstrated an asso- ciationbetweenoccurrence of a complicationandpatientswho underwent a tracheotomy prior to MDO (OR, 2.9 [95% CI, 1.2- 7.1]), increasing length of follow-up (OR, 1.2 [95%CI, 1.0-1.3]), and patients who required 2 or more airway procedures (OR,

Rates of surgical success and complications are de- scribed in Table 1. The overall success rate for MDO in the co- hort was 75.6%. There was a significant difference in the suc- cess rate between patients who underwent tracheotomy prior to MDO (67.7% successfully decannulated) compared with those who underwent MDO first (83.6% avoided trache- otomy; P < .001). In the entire cohort, there were 72 patients who underwent tracheotomy, 62 who underwent trache- otomy as an initial procedure, and 10 who underwent trache- otomy afterMDO. Approximately one-third of thesewere per- formed at outside institutions prior to referral. Five of the 10 patients who required a tracheotomy after MDO were even- tually decannulated. The overall complication ratewas 26.8%, with a significantly higher complication rate in the trache- otomy-first subgroup compared with the MDO-first sub- group (38.7% vs 14.8%, respectively; P = .003). In the overall cohort, premature bony consolidation (11.4%), open bite de- formity (7.3%), and TMJ ankylosis (4.1%) were the most com- mon complications. Patients who underwent a tracheotomy first had greater rates of premature consolidation (19.4% vs 3.3%; P = .005) and TMJ ankylosis (8.1% vs 0%; P = .06) com- pared with those who underwent MDO first. Among the 5 pa- tients who developed TMJ ankylosis, 1 was a patient with am- nioticbandsyndrome andbilateral Tessier 7 cleftswho required 4distractionprocedures anddeveloped ankylosis after the last distraction. One patientwithCatel-Manzke syndrome hadpre- existing TMJ ankylosis that was thought to be related to her underlying syndrome, and another had Goldenhar syndrome (Pruzansky grade 1). Both of these patients required 3 distrac- tions each. One patient with isolated micrognathia had pre- mature consolidation requiring a second distraction proce- dure that was complicated by a pin site infection, and the last patient had isolated micrognathia requiring only 1 distrac- tion. In this case, the cause of the TMJ ankylosis was unclear. In the tracheotomy-first subgroup, univariable logistic re- gressionmodeling identified sex, syndrome diagnosis, and age at distraction as potentially important predictors of surgical success ( Table 2 ). When adjusting for sex and age at distrac- tion, patients with CFM–Goldenhar syndrome had the lowest

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

jamaotolaryngology.com

45