Visual Function Improvement After Optic Nerve Sheath Fenestration in Osteopetrosis Patients with Optic Canal Stenosis: A Report of Two Cases

Optic Canal Diameters According to Age in the Pediatric Population

PURPOSE

To determine the normal range of optic canal diameters in the Turkish pediatric population.

METHODS

Brain, orbital, and maxillofacial computed tomography examinations were evaluated retrospectively. Children with cranial bone disorders affecting the bone structure of the optic canal were excluded from the study. Oblique axial and oblique sagittal multiplanar reformatted images were created in accordance with the axis of the optic canal on both sides, and measurements were taken from the shortest transverse and craniocaudal diameters of the optic canal in these images.

RESULTS

Two hundred computed tomography examinations were evaluated. One hundred two of the patients were female and the rest were male. Patient ages ranged from 1 to 211 months (mean ± standard deviation: 86.42 ± 65.39 months). There was no significant difference between the transverse and craniocaudal optic canal diameters between sexes (P > .05). Therefore, the analyses were reevaluated in the entire patient series, regardless of sex. No significant correlation was found in the correlation test performed between optic canal diameters according to the age of the patients. No statistically significant difference was observed between the right and left optic canal diameters.

CONCLUSIONS

The determination of normal values of tissues, structures, and organs that differs with age has an important role in pediatric radiology. The authors believe that the determination of normal optic canal diameters according to certain age groups will meet the needs of daily practice. [J Pediatr Ophthalmol Strabismus. 2021;58(5):319-323.].

Bilateral optic nerve compression secondary to skull hyperostosis from vitamin A deficiency

A 15-year-old boy with a history of autism spectrum disorder presented with bilateral progressive blurry vision and nyctalopia. Initial examinations, including optical coherence tomography scans of the macula and optic nerve, were within normal limits. Subsequent examination revealed trace pallor of the right optic nerve. Computed tomography and magnetic resonance imaging of the brain demonstrated diffuse thickening of calvarial bone with bilateral optic nerve compression. Laboratory evaluation was notable for profound vitamin A deficiency. The patient underwent optic nerve decompression and vitamin A supplementation with postoperative improvement in visual acuity of both eyes.

Hematopoietic stem cell transplantation-induced bone remodeling in autosomal recessive osteopetrosis: Interaction between skeleton and hematopoietic and sensory nervous systems

OBJECTIVE

Autosomal recessive osteopetrosis (ARO) is a rare congenital disorder of defective bone resorption. The inability of osteoclasts to resorb bone compromises the development of bone marrow cavity, and ultimately, leads to defective hematopoiesis and death within the first decade. The only curative treatment currently available for certain forms of ARO is hematopoietic stem cell transplantation (HSCT). Infants over ten months of age suffering from ARO are defined as patients with advanced disease; HSCT to these patients is associated with high risk of transplant-related mortality (TRM). Because of the extreme variability of ARO clinical phenotypes, the most reliable predictive factor of TRM and graft failure risk is the residual bone marrow space volume.

CASE REPORT

We report clinical and radiological outcomes of one patient affected by ARO and treated with HSCT at advance stage of the disease. We describe the anomalies in various tissues, including bone marrow and bones at the moment of the diagnosis and document their gradual disappearance after HSCT until their complete resolution based on magnetic resonance imaging (MRI) observations. We provided radiological images of the cranial vault bone structure modifications, correlating the radiological appearance of the optical canals and nerves and of the cerebellum with the neurological manifestations of the disease.

CONCLUSIONS

Our results demonstrate that MRI is a highly sensitive technique that provides excellent images of bone marrow space before and after HSCT without exposing children to ionizing radiation. MRI also permits us to evaluate post-transplant skeletal remodeling and the deriving changes in the hematopoietic and sensory system.