SYM9.9E Necker Experience of Frontofacial Monobloc Advancement with Distraction (FFMBA): 145 cases in faciocraniosynostotic children

Abstract

Introduction: in faciocraniosynostotic children, simultaneous correction of raised intracranial pressure, frontal retrusion, exorbitism, and facial retrusion causing sleep apnea syndrome can be achieved by frontofacial monobloc advancement. Methods: Since year 2000, 145 children aged between 9 months and 17 years were operated on by the same surgeon (EA) of a frontofacial Monobloc osteotomy. Frontal bone elevation was performed in all cases. Main group of 138 patients underwent insertion of 4 internal distractors (KLS Martin, Arnaud and Marchac distractors). A subgroup of 7 patients aged under 15 months underwent postoperative external traction (3kg) applied to a zygomatic transfacial pin (K-wire 2mm in diameter). In the subgroup of young patients, a prolongated sedation was necessary during one week. In all primary patients (never operated of a frontoorbital advancement before), transposition periosteal flaps were used to seal the anterior fossa.A systematic simple protocol of lumbar puncture during 3 days was used in case of suspicion of postoperative CSF leak. In a subgroup of 109 patients who were prospectively evaluated for respiratory outcome, 44% had a systematical removal of adenoids and tonsils prior to Monobloc. Results: in 95% of patients exorbitism was corrected. Class I occlusion was obtained only in 75% of the cases at the end of distraction. The mean OSAS measured on AHI was reduced from 19.1 (+/-17.2) to a mean 12.5 (+/-13.6). But, only the patients in whom adenoids and tonsils were removed preoperatively benefited frankly from the Monobloc.The rate of major infections was 2% (3 out of 145) mostly in secondary patients. The rate of mortality was 1,3 % (2 patients out of 145): one was due to an untreated preoperative Chiari, the other to very severe venous malformations (both these complications occurred at the beginning of our experience). Minor complications included frequently contaminations of internal distractors (30%), and CSF leaks requiring temporary treatment in 8%. The use of transfacial pin was detrimental to tooth buds but helped correction of airways obstruction in severe patients around one year of age. Postoperative OSAS was significantly lower when premonobloc ENT surgery was performed (tonsils and adenoids) Conclusions: Recommendations for surgical management of FFMBA include the following: - Preoperative screening including CT scan, MRI with venous analysis, polysomnography and ophthalmologic examination. - Preliminary systematic ENT removal of tonsils and adenoids (if significally present). - Preliminary management of Chiari by posterior vault distraction associated to foramen magnum decompression if necessary - Prefer primary cases for FFMBA allowing systematic closure of anterior cranial fossa by bilateral anteriorly based pericranial flaps (those flaps rarely available in previously operated patients)- This step necessitates frontal bone elevation - Use 4 internal distractors with consolidation time of 4–6 months. - Sedation of 2–4 days useful in the immediate post-operative period. - Slow distraction rate to 0,5mm/day starting at day 3 until completion (20–25 mm). - Obtain overcorrection at orbital level, and at dental level if possible. - In the very young and very severe, a very early FFMBA could be performed with adjunction of transfacial pin and external traction during one week. - Postoperatively, reeducate mouth opening to prevent trismus