Imaging review of the anterior skull base

Systematic Review: Success Rate of Endoscopic Endonasal versus Combined Endonasal and Transorbital Neuroendoscopic Approach for Nontraumatic Cerebrospinal Fluid Leak Repairs in the Lateral Recess of Sphenoid Sinus

Background  Cerebrospinal fluid (CSF) leaks from the lateral recess of the sphenoid sinus (LRS) occur due to a skull base defect and are important to treat due to the associated morbidity, e.g., life-threatening meningitis. Nontraumatic CSF leaks have a predilection toward obesity which is a rising phenomenon. LRS is notoriously difficult to access because of its lateral location and its associated neurovascular complications. An alternative surgical corridor has been explored which is the transorbital neuroendoscopic (TONES) approach. Objective  To compare the success rate of the endoscopic endonasal with the TONES approaches. Rationale  This is the first systematic review on the endoscopic endonasal and combined transorbital approaches to treat CSF leaks from the LRS. Method  A PRISMA-concordant systematic review. PubMed, MEDLINE, EMBASE, Web of Science, and SCOPUS were searched. The studies underwent abstract and full-text screening by two reviewers. The data collected included patient demographic, surgical approach, reconstruction method, layers and materials, follow-up period, ROBINS-I bias, complications, and success rate. Results  In total, 26 of 4,385 studies were included for further synthesis. Of these studies, a total of 336 patients were identified from a cohort of 910 patients. The endoscopic endonasal approach showed a repair success rate of 95.24% and the combined TONES and endonasal approach showed a success rate of 100%. Conclusion  Both the endoscopic endonasal and transorbital approach provide a good success rate. However, due to the small TONES sample, large, randomized control trials are needed.

Computed tomographic assessment of risk of anterior skull base injury of adult patients in tertiary care centre: a cross-sectional study

Background and objectives

Functional endoscopic sinus surgery (FESS) carries the risk of anterior skull base injury. Understanding computed tomography of the paranasal sinuses (CT PNS) and anatomical variations is crucial before surgery. Several classifications, including Kero's, Gera's, and Thailand-Malaysia-Singapore (TMS), assess the risk of skull base injury. The objective was to determine the risk of anterior skull base injury using CT PNS in adult patients.

Methods

A study of 188 patients with head and paranasal sinus pathologies used CT scans to measure olfactory fossa depth, the angle between lamina papyracea and horizontal plane, and the distance from the orbital rim to the cribriform plate. Variations were classified using Kero's, Gera's, and TMS classifications.

Results

The study involved 188 individuals aged 18-85, with OF depths ranging from 0.1 to 0.52 cm. Kero's Class I was observed in 82.44% and 81.38% of individuals, while distances from orbital floor to cribriform plate and ethmoidal roof ranged from 1.37 to 2.93 cm. TMS Type I was observed in all individuals, and the angle between lateral lamella of the cribriform plate and cribriform plate ranged from 34° to 85°. Gera's Class II was observed in 77.12% and 84.57% of individuals.

Conclusion

CT PNS provides important anatomical information for assessing the risk of skull base injury during FESS. Kero's, Gera's, and TMS classifications can be utilized to evaluate this risk. The study findings provide insights into the variations in olfactory fossa depth, distance measurements, and angle, which can aid in preoperative planning and reducing complications during FESS in Nepalese populations.

Use of Rescue Flaps in the Reconstruction of Anterior Skull Base Defects

Several traumatic and non-traumatic defects in the anterior base of the skull require incessant reconstruction to stop the leakage of cerebrospinal fluid (CSF). Reconstruction of these defects at the earliest is essential to achieve an uncomplicated recovery. Various innovations in surgical procedures are seen contemporarily in reconstructing the weaknesses in the anterior part of the skull base. Multilayer grafting techniques successfully repair minor dural defects, while significant dural defects require pedicled vascularized grafts for reconstruction. Using nasoseptal flaps (NSFs) has drastically lowered the instances of CSF leaks in significant dural defects. The rescue flap is an advancement in the approach of the NSF, which was discovered in 2011. This flap is made in a downward direction with the formation of a posterior superior incision so that it does not interfere with the mucosal flap. A small incision is made at the ostium of the sphenoid bone, which is brought into the anterior aspect of the superior nasal septum. The mucosa is elevated inferiorly through the ostium of the sphenoid bone, so some septal branch of the sphenopalatine artery is preserved. In this way, the vascular supply is protected. However, in cases of CSF leak during operations, this rescue flap is reverted into an atypical and standard NSF for reconstructing the base of the skull. This rescue flap technique gives a binaural approach to sella in a way that does not compromise the pedicle during tumor removal. This rescue flap significantly decreases the duration of care in the post-operative phase and improves the cost efficiency of the surgery by avoiding donor site morbidity.

Supratentorial hemangioblastoma at the anterior skull base: A case report

BACKGROUND

Hemangioblastoma (HB) is a rare tumor, comprising about 2% of all intracranial tumors. Although it is a benign tumor, due to the abundant blood supply and its close relationship with adjacent cerebral blood vessels, surgical resection is difficult and may cause complications such as bleeding. If HB can be correctly diagnosed before surgery, complications can be avoided by methods such as vascular embolism before surgery.

CASE SUMMARY

A 51-year-old male patient was admitted to our hospital because of blurred vision in his left eye for 2 years. Ophthalmological examination revealed oculus dexter vision acuity of 1.0 and oculus sinister vision acuity of 0.6. His left vision had tubular visual field, while his right vision had a partial defect. Computed tomography and magnetic resonance imaging showed a mass lesion at the left anterior base of the skull, which could have been a meningioma. During the operation, the tumor was found to be located at the entrance of the left optic nerve tube, closely adhering to the left optic nerve and the blood supply was extremely abundant. The tumor was carefully separated and diagnosed as HB postoperatively after pathological examination.

CONCLUSION

A rare HB at the anterior skull base could be distinguished by its imaging features, which is essential to the surgical procedures.

[Combination of CT and MRT in the diagnostic of middle ear cholesteatoma. Fusion technology is precise localization tool]

Computed tomography (CT) and magnetic resonance imaging (MRI) methods of the middle ear cholesteatoma diagnostic have its advantages and disadvantages. Fusion technology is a post-processing process of CT and MRI images. Its main advantage is the localization of MR-hyperintensive cholesteatoma within the bony anatomical structures obtained on CT, which provides the surgeon with important information both before planning the primary surgical intervention and during a second revision for recurrent cholesteatoma.

What's that smell? A pictorial review of the olfactory pathways and imaging assessment of the myriad pathologies that can affect them

The olfactory pathway is composed of peripheral sinonasal and central sensorineural components. The wide variety of different pathologies that can affect the olfactory pathway reflect this complex anatomical relationship. Localising olfactory pathology can present a challenge to the reporting radiologist. This imaging review will illustrate the normal anatomy of the olfactory system and describe a systematic approach to considering olfactory dysfunction. Key concepts in image interpretation will be demonstrated using examples of olfactory pathway pathologies.

Involvement of the Olfactory Apparatus by Gliomas

The olfactory bulbs and tracts are central nervous system white matter tracts maintained by central neuroglia. Although rare, gliomas can originate from and progress to involve the olfactory apparatus. Through a Health Insurance Portability and Accountability Act-compliant retrospective review of the institutional teaching files and brain MR imaging reports spanning 10 years, we identified 12 cases of gliomas involving the olfactory bulbs and tracts, including 6 cases of glioblastoma, 2 cases of anaplastic oligodendroglioma, and 1 case each of pilocytic astrocytoma, diffuse (grade II) astrocytoma, anaplastic astrocytoma (grade III), and diffuse midline glioma. All except the pilocytic astrocytoma occurred in patients with known primary glial tumors elsewhere. Imaging findings of olfactory tumor involvement ranged from well-demarcated enhancing masses to ill-defined enhancing infiltrative lesions to nonenhancing masslike FLAIR signal abnormality within the olfactory tracts. Familiarity with the imaging findings of glioma involvement of the olfactory nerves is important for timely diagnosis and treatment of recurrent gliomas and to distinguish them from other disease processes.