Morphometric analysis of occipital condyles using alternative imaging technique

Occipital bone and tumor-induced osteomalacia: a rare tumor site for an uncommon paraneoplastic syndrome

INTRODUCTION

Tumor-induced osteomalacia (TIO) is an uncommon paraneoplastic syndrome due to the overproduction of fibroblast growth factor 23 (FGF23). It is predominantly caused by mesenchymal tumors and cured upon their complete removal. Non-surgical treatment is an alternative option but limited to specific clinical conditions.

METHODS

We report a challenging case of TIO caused by a tumor involving the occipital bone. We also performed a literature review of TIO caused by tumors localized at this site, focusing on clinical findings, treatment, and outcomes.

RESULTS

The patient, a 62-year-old male, presented with a long-lasting history of progressive weakness. Biochemical evaluation revealed severe hypophosphatemia due to low renal tubular reabsorption of phosphate with raised intact FGF23 values. A 68 Ga-DOTATATE PET/TC imaging showed a suspicious lesion located in the left occipital bone that MRI and selective venous catheterization confirmed to be the cause of TIO. Stereotactic gamma knife radiosurgery was carried out, but unfortunately, the patient died of acute respiratory failure. To date, only seven additional cases of TIO have been associated to tumors located in the occipital bone. Furthermore, the tumor involved the left side of the occipital bone in all these patients.

CONCLUSION

The occipital region is a difficult area to access so a multidisciplinary approach for their treatment is required. If anatomical differences could be the basis for the predilection of the left side of the occipital bone, it remains to be clarified.

Occipital condyle screw fixation after posterior decompression for Chiari malformation: Technical report and application

BACKGROUND

Surgical techniques for stabilization of the occipital cervical junction have traditionally consisted of screw-based techniques applied in conjunction with occipital plating and rods connected to subaxial instrumentation in the form of pars, pedicle, or lateral mass screws. In patients with type 1 Chiari malformation (CM-1) and evidence of occipital cervical junction instability who have undergone posterior decompression, the occipital condyle (OC) represents a potential alternative cranial fixation point. To date, this technique has only been described in pediatric case reports and morphometric cadaver studies.

METHODS

Patients underwent posterior fossa decompression for treatment of CM. Subsequently, patients received occipital cervical stabilization using OC screws.

RESULTS

Patients were successfully treated with no post-operative morbidity. Patient 2 was found to have pseudoarthrosis and underwent revision. Both patients continue to do well at 1-year follow-up.

CONCLUSION

Placement of the OC screw offers advantages over traditional plate-based occipital fixation in that bone removal for suboccipital decompression is not compromised by the need for hardware placement, screws are hidden underneath ample soft tissue in patients with thin skin which prevents erosion, and the OC consists of primarily cortical bone which provides for robust tricortical fixation. These cases demonstrate the novel application of the OC screw fixation technique to the treatment of occipital cervical junction instability in adult patients undergoing simultaneous posterior fossa decompression.

Assesment of Prelacrimal Recess in Patients With Maxillary Sinus Hypoplasia Using Cone Beam Computed Tomography

BACKGROUND

The prelacrimal recess approach, is frequently preferred in creating a minimally invasive surgical corridors.

OBJECTIVE

The aim of this study was to evaluate the Prelacrimal recess (PLR) anatomy using Cone Beam Computed Tomography in patients with Maxillary Sinus Hypoplasia.

METHODS

The paranasal Cone Beam Computed Tomography series of 84 adults were analyzed retrospectively. The antero-posterior and mesio-distal widths of the PLR and the antero-posterior width of the naso-lacrimal duct were measured. The patients were divided into three groups according to the antero-posterior width of PLR to evaluate the feasibility of prelacrimal recess approach as Type 1 (0-3 mm), Type 2 (>3-7 mm) and Type 3 (>7 mm).

RESULTS

The mean antero-posterior width of PLR was 3.11 ± 1.49mm in the patients and 4.77 ± 1.76 mm in the controls. The mean mesio-distal width of PLR was 7.64 ± 1.49 mm in the patients and 3.17 ± 2.05 mm in the controls. The mean antero-posterior width of naso-lacrimal duct was 9.58 ± 2.80 mm in the patients and 9.46 ± 2.42 mm in the controls.

CONCLUSIONS

The width of the antero-posterior PLR in patients with Maxillary Sinus Hypoplasia was found to be significantly lower in comparison to individuals with normal maxillary sinuses in the measurements performed on paranasal Cone Beam Computed Tomography scans. Hence, while planning a Functional Endoscopic Sinus Surgery with prelacrimal recess approach for maxillary sinus, the anatomical structure of the naso-sinusoidal region should be carefully analyzed, and individual anatomical variations such as Maxillary Sinus Hypoplasia should not be ignored.