Bone Abstracts

Fibrous dysplasia (FD) is a benign skeletal disease caused by somatic activating mutations of G_sα leading to formation of expansile fibroosseous lesions. These may occur in isolation or in association with McCune-Albright syndrome (MAS), characterized by skin pigmentation and hyperfunctioning endocrinopathies, including growth hormone (GH) excess. FD in the craniofacial skeleton may result in significant morbidity including facial asymmetry, vision and hearing loss, nasal obstruction, malocclusion, and pain. Craniofacial FD is sometimes treated surgically; however post-operative regrowth of FD tissue may result in recurrence or even worsening of craniofacial deformity.

Objectives: To determine outcomes and indications for operations and re-operations in a large cohort of subjects with craniofacial FD, and to identify risk factors for post-operative regrowth.

Methods: Clinical data from subjects in a long-standing natural history study of FD/MAS were reviewed. Surgeries were categorized as follows: debulking (partial removal and/or recontouring of FD), reconstruction (resection of FD bone with introduction of hardware and/or grafting material), optic nerve decompression, aneurysmal bone cyst enucleation, or biopsy.

Results: Of 175 patients with FD/MAS, 130 (74%) had FD involving the craniofacial skeleton. Of these, 31 (24%) underwent a total of 86 craniofacial surgeries. The distribution of surgeries was as follows: debulkings 36 (42%), reconstructions 26 (30%), optic nerve decompressions 15 (17%), aneurysmal bone cyst enucleations 9 (10%), biopsies 9 (10%). The mean length of post-operative follow-up was 13.6 years (range 0–39, S.D. 10.6). Re-operations were performed in 34 (40%) of cases. The most common indication for re-operation was FD regrowth, which occurred significantly more frequently after debulking procedures (24/36, 67%) than reconstructions (7/26, 27%) (P=0.004). The prevalence of MAS-associated GH excess was higher in the surgically treated group (11/31, 35%) than in patients who were managed non-operatively (16/99, 16%) (P=0.04). Re-operations for FD regrowth were more common in patients with GH excess (16/34, 47%) than in patients without GH excess (18/50, 36%) (P=0.05).

Conclusions: Post-operative FD regrowth and re-operations are common after craniofacial surgery. If surgery is undertaken, resection and reconstruction with hardware and/or grafting material may result in less regrowth and fewer re-operations than more conservative debulking and recontouring techniques. Practitioners should be aware that MAS-associated GH excess is a risk factor for craniofacial morbidity and post-operative FD regrowth.

Disclosure: The authors declared no competing interests.