Orthognathic surgery in Melnick–Needles-Syndrome. Case report and review of the literature

Abstract

Melnick–Needles Syndrome (MNS) is a congenital syndrome associated with severe architectural disorder of the skeletal system that can cause significant effects on the craniofacial skeleton including poor aesthetics, impaired speech and masticatory problems. The authors report a case of a female patient who experienced masticatory constraint, hindered speech and functional problems related to a severe bite dysfunction due to the mandibular hypoplasia and the underlying bony architectural disorder associated with MNS. The patient underwent bilateral sagittal split osteotomy (BSSO) to correct her skeletal malocclusion and improve the characteristic aesthetics and speech. The inherent bony abnormalities with their altered collagen structure presented unique challenges to orthognathic surgery in this patient with an unpredictable bone healing process. In MNS patients a fragile trabecular bone structure and an increased bleeding tendency is thought to delay or forestall wound healing. The patient was treated successfully with BSSO and monocortical plate fixation following a well-established algorithm from orthodontic preparation to surgical protocol. A very satisfying outcome has been achieved, concerning functional rehabilitation and aesthetic improvement. A review of the literature revealed that little is known about bone regeneration and fracture healing in cases with MNS.

Melnick–Needles Syndrome (MNS), a form of osteodysplasty, was first reported by Melnick and Needles in 1966, and is usually diagnosed on the basis of characteristic facial and radiographic findings .

The osseous abnormalities involve the majority of the axial and appendicular skeleton. The syndrome is characterised by short stature, prominent forehead, bilateral exophthalmus, fullness of the cheeks and retrognathia. The histological findings regarding the bony micro-architecture include cortical irregularities and an aberrant trabecular structure combined with an increased collagen content that leads to advanced sclerosis . Severe mandibular hypoplasia can cause upper airway restriction, an increased incidence of sleep apnea and pneumonias and, occasionally, respiratory failure.

The authors report a case of an 18-year-old woman with MNS who suffered from the distinctive aesthetic traits and impaired speech.

Case report

An 18-year-old woman presented with a severe complaint of unfavourable aesthetics and functional masticatory problems. Her chief complaint was her affected bite function due to her deep bite and the slight sigmatism in her speech. She had been diagnosed previously as having MNS and different operations on her extremities and her urinary tract had been performed during childhood.

Craniofacial examination revealed a slight hypertelorism, mandibular hypoplasia with retrognathia, obtuse mandibular angle and fullness of her cheeks and a short lower facial height ( Fig. 1 a) . Intraoral examination revealed a deep bite with distinct over jet and class II occlusion, misaligned denture and lateral open bite ( Fig. 1 b).

Fig. 1
(a) Clinical preoperative evidence. (b) Preoperative intraoral situation.

Radiological examination revealed a sclerosis of the skull base, a moderate scoliosis and kyphosis of the spine, curved clavicles, a small rib cage and accented bowing of the humerus, radius, ulna, and tibia. She typically suffered from a metaphyseal flaring of her long bones, a coxa valga, curved bones of the base of pelvis and hypoplastic pubic bones. Panoramic and lateral cephalometric X-rays revealed pronounced mandibular hypoplasia and the manifest overjet ( Fig. 2 a and b) . The mandible is extraordinarily thin, especially in the retromolar areas; these characteristic lucencies should not be confused with cysts .

Fig. 2
(a) Lateral preoperative cephalometric X-ray. (b) Preoperative panoramic X-ray.

Surgery

Model surgery was performed and the mandibular advancement was calculated to be 4.5 mm on the left side and 6.5 mm on the right. An individual acrylic splint was constructed, fixing the final position of the mandible. After a routine blood test and under aseptic precautions and general anaesthesia the classical bilateral sagittal split osteotomy, according to Obwegeser and DalPont, was performed and the predetermined advancement was achieved at the time of surgery. The osteotomy site was fixed by Medartis orthognathic plates (Modus ® OSS 2.0) and intermaxillary fixation was achieved by self threaded intermaxillary fixation screws. Fixation was maintained for 3 days and then changed to elastics under the surveillance of the authors’ orthodontic department. The most visible effects were the considerable bite raise and the striking harmonization of the facial features ( Fig. 3 a and b) .

Jan 26, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Orthognathic surgery in Melnick–Needles-Syndrome. Case report and review of the literature
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