Indications and Long-Term Outcomes of Surgical Treatment for Craniofacial Fibrous Dysplasia

Background:  Fibrous dysplasia (FD) is a benign skeletal disease caused by somatic activating mutations of Gs-alpha leading to formation of expansile fibro-osseous 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. 

Statement of the Problem:  Historically, craniofacial FD (CF-FD) has been treated surgically, with conservative treatments such as shaving/debulking/recontouring or more radical approaches that involve subtotal resections with or without reconstruction.  Previous clinical studies have shown that there may be post-operative regrowth of FD tissue, resulting in recurrence or even worsening of craniofacial deformity.¹  The etiology of CF-FD regrowth remains poorly understood. 

Objectives: Our objectives were to retrospectively determine the surgical indications, recurrence rates, and reasons for re-operation in a large cohort of Polyostotic FD/MAS patients, and to identify risk factors for post-operative regrowth.

Materials and Methods: Clinical data was obtained from subjects in a long-standing natural history study of FD/MAS (Screening and Natural History Study of Fibrous Dysplasia, NIH 98-D-0145).  Indications for surgery were categorized as:  facial deformity, visual loss, hearing impairment, nasal airway obstruction, malocclusion, or aneurysmal bone cyst (ABC).  Surgeries were divided as:  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. 

Methods of Data Analysis:  Statistical analysis was performed with unpaired t-test and Fisher’s exact test.

Results and Outcomes Data: Of 169 patients with FD/MAS, 133 (79%) had CF-FD.  Of these, 33 patients (25%) underwent a total of 95 craniofacial operations.  The most common indication for initial operation was facial deformity (24%).  Of the 33 patients, 23 (70%) underwent a secondary procedure in the same anatomic location.  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, SD 10.6).  The most common indication for re-operation was FD regrowth, which occurred significantly more frequently after debulking procedures (26/36, 72%) than reconstructions (10/30, 33%) (p = 0.0027). The prevalence of MAS-associated GH excess was higher in the surgically treated group (12/36, 36%) than in patients who were managed non-operatively (14/100, 14%) (p = 0.0098).  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 = 0.0465).

Conclusions:  Facial deformity was the most common indication for surgical intervention in our patient cohort.  Post-operative FD regrowth and re-operation are common after craniofacial surgery; in our patient population, FD regrowth with facial deformity was the most common reason for secondary operation.  Our study corroborated previous observations, which indicate that resection and reconstruction with hardware and/or grafting material may result in less regrowth and fewer re-operations as compared to more conservative debulking and recontouring techniques.²  Finally, we also found that MAS-associated GH excess is a risk factor for craniofacial morbidity and post-operative FD regrowth.  

1. Chen, YR et al.  “Treatment of Craniomaxillofacial Fibrous Dysplasia: How Early and How Extensive?”  Plast Reconstr Surg.  86 (5): 835-42, 1990.

2. Valentini, V. et al.  “Craniomaxillofacial Fibrous Dysplasia: Conservative Treatment or Radical Surgery? A Retrospective Study on 68 Patients. .”  Plast Reconstr Surg.  123: 653-60, 2009.