Sclerosing bone dysplasias with involvement of the craniofacial skeleton

Decompression of the internal auditory canal via the retrosigmoid approach in a patient with Camurati-Engelmann disease: illustrative case

BACKGROUND

Camurati-Engelmann disease (CED) is a rare condition characterized by hyperostosis of the long bones and skull base. Symptoms include contractures and pain in affected extremities but can also include manifestations of cranial hyperostosis such as intracranial hypertension, Chiari malformation, exophthalmia, frontal bossing, and several cranial neuropathies due to cranial foraminal stenosis.

OBSERVATIONS

This report describes a 27-year-old patient with suspected CED who developed progressive intermittent facial nerve paresis, hemifacial spasms, and a decrease in hearing. There were no symptoms of increased intracranial pressure or vertigo. Radiological evaluation showed a significant thickening of the skull base with serious bilateral internal auditory canal stenosis. Because of the progressive nature of the aforementioned cranial neuropathies in combination with the correlating severe radiological compression, a surgical decompression of the facial nerve and vestibulocochlear nerve was performed via a retrosigmoid approach with intraoperative monitoring. Postoperative facial nerve function was intact. Hearing and vestibular function were unchanged. There were no more episodes of facial nerve palsy or spasm.

LESSONS

To the authors' knowledge, this is the first report to describe decompression of the internal auditory canal via a retrosigmoid approach for symptomatic facial and cochlear nerve compression in a patient with CED.

Computed Tomography Diagnostic of Uncommon Case of Osteopetrosis in 80-Year-Old Man-Case Report

Background and Objectives: During osteopetrosis course, impaired bone remodeling induces skeletal osteosclerosis and abnormally dense bones, which, however, are brittle and susceptible to low-energy fractures. In this study, radiological evaluation and densitometric measurements of several bones of the skeleton in one of the oldest patients in the world suffering from osteopetrosis was presented. Materials and Methods: Volumetric bone mineral density measurements of the examined bones in an 80-year-old man were performed using two different quantitative computed tomography techniques. Results: The obtained results show higher values of the volumetric bone mineral density of the trabecular bone in lumbar spine than in the cortical bone compartment. T-score and Z-score in this patient reached values of 27–28 and 31–32, respectively. Conclusions: The obtained densitometric data may serve for further diagnostic purposes of osteopetrosis. As documented, the severity of the osteosclerotic changes of bones were higher in this patient than in most other described cases. Moreover, radiological signs diagnosed in this patient were characteristic for all types of osteopetrosis making this case very uncommon.

Decompressive Cranial Vault Remodeling in Osteosclerotic Robinow Syndrome

We present a novel application of endocranial burr contouring for cranial vault expansion as a surgical adjunct during decompressive craniectomy in patients with cranial osteosclerosis. A 16-year-old female with osteosclerotic Robinow syndrome complicated by slit ventricle syndrome presented with refractory intracranial hypertension following external ventricular drain placement. Symptoms included severe headaches and altered mental status. Given the severe intracranial volume restriction secondary to massive calvarial thickening (2.5 cm), the patient was taken to the operating room for urgent surgical decompression. After frontal and parietal craniectomy, burr and osteotome contouring were used to remove two-thirds of the endocranial calvarial bone flap thickness resulting in a 9% cranial vault expansion while preserving an overall normal head size. There were no immediate postoperative complications. At over 3 years postoperatively, the patient had reduced headaches, maintained adequate shunt function, and has not required further vault reconstruction.

How rare bone diseases have informed our knowledge of complex diseases

Rare bone diseases, generally defined as monogenic traits with either autosomal recessive or dominant patterns of inheritance, have provided a rich database of genes and associated pathways over the past 2-3 decades. The molecular genetic dissection of these bone diseases has yielded some major surprises in terms of the causal genes and/or involved pathways. The discovery of genes/pathways involved in diseases such as osteopetrosis, osteosclerosis, osteogenesis imperfecta and many other rare bone diseases have all accelerated our understanding of complex traits. Importantly these discoveries have provided either direct validation for a specific gene embedded in a group of genes within an interval identified through a complex trait genome-wide association study (GWAS) or based upon the pathway associated with a monogenic trait gene, provided a means to prioritize a large number of genes for functional validation studies. In some instances GWAS studies have yielded candidate genes that fall within linkage intervals associated with monogenic traits and resulted in the identification of causal mutations in those rare diseases. Driving all of this discovery is a complement of technologies such as genome sequencing, bioinformatics and advanced statistical analysis methods that have accelerated genetic dissection and greatly reduced the cost. Thus, rare bone disorders in partnership with GWAS have brought us to the brink of a new era of personalized genomic medicine in which the prevention and management of complex diseases will be driven by the molecular understanding of each individuals contributing genetic risks for disease.

Long-Term Follow-Up of Bimaxillary Osteomyelitis Associated with Autosomal Dominant Osteopetrosis: A Case Report

Osteopetrosis (OP) is a rare metabolic bone disease characterized by a generalized increase in skeletal mass. The disease is characterized by increased susceptibility to develop osteomyelitis of the jaws. We report a case of clinical and radiological progression of bimaxillary osteomyelitis in a patient with autosomal dominant OP. The patient presented non simultaneous osteomyelitis in both upper and lower jaws with time interval of 10 years. The osteomyelitis of maxilla resulted in oroantral fistula formation and required surgical closure with Bichat fat pad flap. The mandibular osteomyelitis resulted in sequestra formation and pathological fracture and required multiple debridement procedures. Both maxillary and mandibular osteomyelitic foci were persistent and healing required more than 2 years. The case confirms the possibility of development of non simultaneous bimaxillary osteomyelitis in patients with OP. The case enhances the need of close follow- up and preventive measures in patients with OP.