Consolidation Time and Relapse: A Systematic Review of Outcomes in Internal versus External Midface Distraction for Syndromic Craniosynostosis

Abstract

Background: The choice between internal and external distraction osteogenesis for midface advancement in patients with syndromic craniosynostosis is based primarily on surgeon preference and expertise. However, differences in outcomes between the two techniques have been sparingly compared. In this work, the authors performed a systematic review to compare outcomes between internal versus external midface distraction. Methods: A systematic review was performed of studies published between 1998 and 2018 (61 studies included; n = 689 patients). Operative characteristics, early reoperations, complications, and relapse rates were extracted. Bias evaluation was performed using the Newcastle-Ottawa instrument. Statistical analyses were performed with independent samples t tests and linear regression analyses (p < 0.05 considered significant). Results: The authors found that external distraction was associated with more Le Fort III osteotomies and hardware adjustments (p = 0.023), whereas internal distraction was associated with more monobloc osteotomies and longer consolidation times (p = 0.008). No significant differences in the distance of midface advancement, reoperations, complications, or relapse rates were noted between internal versus external distraction, although external distraction trended toward a slightly higher relapse rate. Regardless of distraction protocol, consolidation time was found to be a strong negative predictor for relapse (beta = −0.792; p = 0.02). Conclusions: No significant differences were demonstrated in advancement distance, reoperative rates, complication rates, or relapse rates for internal versus external distraction for midface advancement. Regardless of distraction type, consolidation time was strongly inversely associated with relapse rates. The trend toward higher relapse in external distraction is potentially explained by the significantly lower consolidation times.

An Unoperated Crouzon Family Treated with Monobloc Distraction: Challenges and Lessons

“…2 Some of the disadvantages of an external distraction devices are patient discomfort, susceptibility to external forces, possibility of pin dislodgement or intracranial advancement of distraction screws associated with trauma. 7,10,18,19 By their own initiative, our patients wore thick scarves over distractors for discretion, cushioning and warmth. Another drawback is potential for scarring of midface incisions; our patients did not experience keloids or hypertrophic scarring.…”

“…These devices have the advantage of being more stable and covered by soft tissue, which can decrease the external pin site infections, but have a higher likelihood of subcutaneous infections. 7 They can be less awkward for the patient, improving patient compliance and acceptance, thus leading to greater stability and a longer consolidation period compared to the external device. 6 However, they are not without their limitations.…”

“…6 Monobloc frontofacial advancement is commonly performed in childhood with distraction osteogenesis, with timing and technique institutionally dependent. 7 Unfortunately, early intervention is not always possible, due to misdiagnosis, limited healthcare, or cultural factors.…”

Unanticipated Fractures of the Zygomatic-Maxillary Suture in LeFort III Internal Distraction: Salvage of Midfacial Advancement via Rigid External Distraction of an Orphaned LeFort II Segment

“…Internal distractors provide a lower risk of traumatic dislodgement, transcranial pin migration, 5 and less impact on patient quality of life. 6 External distraction provides improved control over force vectors, 7 lower risk of device migration and relapse, 8 and shorter operative time. 6 Internal distraction can be accomplished with skull-zygoma or zygoma-zygoma devices.…”

Monobloc Differential Distraction Osteogenesis

“…Monobloc repositioning of the midface through distraction reduces these complication rates, whereas simplifying the procedure, reducing operative times, and eliminating bone grafting and harvest. 1,2 There are 2 types of midface distraction osteogenesis: differential (external) and unidirectional (internal). Both distraction techniques have contributed to the dramatic reduction in morbidity of traditional monobloc surgery.…”