Frontofacial advancement by internal distraction devices. A technical modification for the management of craniofacial dysostosis in early childhood

Abstract

Normal craniofacial growth is characterized by a different growth pattern of neuro- and viscerocranium. In craniofacial dysostosis (CFD) syndromes there is complex disturbance of this physiological growth pattern. Modern surgical management of CFD is staged with respect to the severity of the deformity, the age and the development of the patient. Early single stage management of anterior cranial vault deformity and midfacial retrusion in children affected by syndromic craniosynostosis is possible when anterior cranial vault remodelling is performed together with gradual Le Fort III midfacial advancement. One pair of internal distraction devices, placed in accordance with the midfacial growth vector after initial cranial vault remodelling, can be sufficient for this purpose. Technical aspects of this modified frontofacial advancement procedure are presented and discussed based on a case report with a postoperative follow up time of 50 months.

Normal craniofacial growth is characterized by a different growth pattern of neuro- and viscerocranium according to Enlow. The term craniosynostosis describes the premature fusion of craniofacial sutures with consecutive disturbance of craniofacial growth. Premature synostosis may be isolated, complex, or even of syndromal origin leading to the expression of specific phenotypes depending on the location and extent of the affected sutures. If facial growth is also affected, the terms faciocraniostenosis (French) or craniofacial dysostosis (CFD) (Anglo-American) may be applied to describe the inclusion of both neuro- and viscerocranium. Regarding the surgical therapy, nonsyndromic craniosynostosis has to be distinguished from CFD syndromes with the involvement of multiple sutures. For single suture synostosis, current surgical management is focused on the release of the affected suture and regional decompression to enable brain growth and reconstruction of a normal anatomical shape. The surgical strategy depends mainly on the extent of cranial deformity and the patient’s age at surgery. According to Ruiz, in most cases of single-suture synostosis one procedure that simultaneously releases the suture and reshapes the skull is the definitive therapy.

In complex forms, in which the midfacial structures are affected, a progressive course of the malformation might require repeated corrective procedures. Modern surgical concepts favour individually staged management related to age and deformity. Early craniofacial correction within the first years of life is related to neurosurgical and functional indications (intracerebral hypertension, compression of the optic nerve, proptosis/exorbitism with corneal exposure, severe upper airway impairment). Depending on the urgency of intervention surgical techniques are adapted. During infancy up to school age, surgery is focused on cranial decompression and reshaping procedures with respect to the location of the cranial compression. The correction of midfacial deformities due to aesthetic and psychosocial indications can be postponed and is performed during childhood and adolescence (depending on the severity of the deformity and individual psychological strain). Final reconstruction of craniofacial deformities is recommended from 6 years onwards and should achieve stable adult dimensions in the cranio-orbito-zygomatic regions. Correction of occlusal relations is less important and can be achieved by orthognathic surgery after skeletal maturity. Staged management is difficult for the patient due to the persisting obtrusive appearance and repeated procedures with an increased risk of infection. Craniomaxillofacial distraction osteogenesis has become an accepted technique, as severe maxillofacial growth deficiencies can be compensated for using the principle of gradual lengthening of bone and surrounding soft tissues according to Ilizarov. There are still controversies about indications, limitations and technical specifications.

If midfacial retrusion and anterior cranial vault malformation are to be addressed simultaneously in CFD, the surgical plan might consist of anterior cranial vault remodelling by a floating technique according to Marchac, in combination with advancement of the midfacial complex after Le Fort III disimpaction by one pair of internal distraction devices. The authors present their experience with this technical modification in a 30-month-old patient affected by Morbus Crouzon. The follow up since the craniofacial procedure is 50 months.

Case report

A male patient from Estonia, the youngest of four children of healthy non consanguineous parents, affected with a severe form of Crouzon’s syndrome was referred to the authors’ institution for secondary craniofacial correction predominantly due to a functional indication. Early frontal decompression within his first year of life was performed in Estonia due to increased intracerebral pressure. At 30 months the patient was referred to the authors’ institution due to increasing functional impairment caused by the syndromal growth deficiency of the anterior skull base and midface and the corresponding syndromal appearance. Preoperative photographic documentation clearly demonstrated severe proptosis and mouth breathing caused by upper airway impairment ( Figs 1 and 2 ). A non-invasive preoperative neurological and ophthalmological check-up revealed no additional pathology. Increased cranial pressure could be assumed as indicated by the ‘fingerprints’ on the postoperative cephalogram.

Fig. 1
Preoperative situation at 30 months of age. Severe form of Crouzon’s syndrome with proptosis and upper airway impairment; frontal view.

Fig. 2
Lateral view of the preoperative situation.

Craniofacial correction was intended as a single step procedure at the age of 30 months. Decompression and fronto-orbital remodelling was planned simultaneously with gradual midfacial advancement after Le Fort III disimpaction. Osteotomies were planned according to Tessier’s design for frontofacial advancement and anterior cranial vault remodelling.

Midfacial advancement should be achieved by gradual distraction using internal distraction devices. For that purpose one pair of KLS-Martin temporal distraction devices for adults according to Marchac (Art. 51-620-35, maximum feed of 35 mm, Gebrüder Martin GmbH, 78532 Tuttlingen, Germany) with Molina pivots (Art. 51-605-01, Gebrüder Martin GmbH, 78532 Tuttlingen, Germany) was selected preoperatively according to the best fit to a three dimensional model of the patient’s skull, taking into consideration that the devices could be positioned in a parallel manner close to the assumed centre of resistance of the ‘facial mass’. With sufficient anchorage of the posterior footplates at the mastoideal regions the devices should be able to push the zygomaticomaxillary complex without twisting it in correspondence with its physiological growth pattern to a position more anterocaudal with reference to the anterior skull base. The devices should provide sufficient stability during the active distraction and consolidation phases, which were supposed to be achieved by the selected model ( Fig. 3 ).

Fig. 3
Three dimensional model of the patient with internal distraction devices. Osteotomy design and segmentation according to P. Tessier. Frontal cover, bandeau and midfacial mobilization at the Le Fort III level.

After coronal incision, subperiosteal dissection and frontal osteotomy the fronto-orbital bandeau was created and mobilized. Individual fronto-orbital remodelling was performed and Le Fort III midfacial disimpaction was achieved by transcranial, transconjunctival and transoral approaches. Both internal distraction devices were inserted zygomatico-temporally in a parallel manner in accordance with the preoperative model ( Figs 3–5 ). After intraoperative activation of the devices and presetting the threads at 3 mm, the frontal bone was attached to the bandeau by non-resorbable transosseous sutures, and both bony units were left floating above the advancing midface. The obvious convergence of the devices to the midline had no impact on the distraction process or the clinical result ( Figs 4–6 ). Subgaleal wound drainage was placed and removed on the second postoperative day. Wound closure was carried out with resorbable sutures. Prophylactic antibiotic treatment consisted of flucloxacillin. The operation time was about 7 h.

Fig. 4
Intraoperative situation after midfacial mobilization and mounting of the devices. Anterior cranial vault remodelling and decompression were achieved after removal of frontal bone cover and reshaping of the ‘bandeau’. Both parts were set back and left floating above the midfacial complex, which was advanced by bilaterally mounted internal distraction devices after Le Fort III disimpaction.

Fig. 5
Intraoperative situation after midfacial mobilization and mounting of the devices (right side view).

Jan 26, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Frontofacial advancement by internal distraction devices. A technical modification for the management of craniofacial dysostosis in early childhood
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