Introduction
The thin bony wall that divides the air cells in the mastoid region within the temporal bone is known as Korner's septum (KS). Following its initial description in 1887, KS became significant in clinical settings. It can occasionally be confused for other ear bone features, such as the medial wall of the antrum or the wall covering the sigmoid sinus. KS is located at the meeting point of two segments of the temporal bone, known as the petrosquamosal suture. This suture is commonly divided into three sections: anterior, middle, and posterior. The cog, with a small bony ridge, is located in the center.
KS extends towards the mastoid apex from its beginnings, close to the back of the jaw joint, and continues across the middle ear cavity. The mastoid cells are split into deep and superficial parts. The septum may occasionally not be continuous, brought on by defects in development or illness-related damage. The majority of the time, KS is discovered close to specific ear anatomical markers. KS can make surgery more difficult, particularly for novice surgeons, as it raises the possibility of facial nerve damage. Additionally, it is more prevalent in those with middle ear disorders such as tympanosclerosis (scarring of the ear drum), where surgical excision of the KS may be advised. Remaining cholesteatomas, a kind of skin growth in the ear, may also be more common in people with KS. This article provides a general overview of KS and its therapeutic importance based on current research.
What Are the Anatomical Sections of Korners Septum, and Their Significance?
Korner's Septum Anatomy (KS): Korner's septum (KS), which correlates to the persistent petrosquamosal suture, splits the mastoid cells into deep and superficial parts. According to HRCT (high-resolution computed tomography) scans of the temporal bone, KS is equally frequent on both sides of the head and is higher in men.
There are three sections in KS:
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Anterior Section: Located at the level of the malleus head, this is the most constant.
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Superior Section: Situated at the superior semicircular canal's level.
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Posterior Section: This section is the least consistent, located at the tympanic sinus level.
According to some researchers, the septum's tympanic area is an osseous ridge known as a "cog." The cog divides the epitympanum into two sections: the posterior portion is located within the superior wall of the tympanic cavity. In contrast, the anterior portion is located in the supratubal recess. Interestingly, KS was present at the mastoid antrum in every patient with cogs. Inflammatory processes in the tympanic cavity may result from reduced airflow between the protympanum and antrum when the cog is present.
KS with Squamous Chronic Otitis Media (COM): Based on the Browning classification, there are two forms of squamous chronic otitis media or middle ear inflammation (COM):
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Inactive (Squamous) COM: Identified by retained debris and pars tensa or flaccida retraction.
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Active (Squamous) COM: Consists of inflammatory, pus-filled middle ear mucosa, squamous-type epithelial debris, and pars flaccida or tensa retraction.
By decreasing airflow, which can result in otitis media, KS can aid in retracting the tympanic membrane (TM), particularly in the posterosuperior or attic regions. The degree of tympanic membrane retraction and mastoid pneumatization correlate, with cholesteatoma more prevalent in less pneumatized mastoids. Nonetheless, well-pneumatized mastoids are equally susceptible to cholesteatoma. Cholesteatoma's etiology is still unknown. However, secondary sclerosis, the condition in which additional bone grows, is linked to the majority of cases of COM. KS is thought to play a role in the etiopathogenesis of COM as a developmental remnant between the temporal squama and the mastoid (petrosquamosal suture persistence).
What Is the Clinical Significance of Korners Septum?
Clinical problems with Korner's septum (KS) might be very severe. Sometimes, during antromastoidectomy (one of the basic surgical procedures used to treat ear diseases) surgery, KS presents as a false medial wall, preventing the antrum from being fully explored. This may lead to a closed space that is not well-ventilated, which could result in inflammation and a relapse of chronic otitis media.
Due to its increased likelihood of leaving behind residual cholesteatoma, especially in the cog-covered posterior region of the epitympanum, KS can also have an impact on middle ear surgery. For patients with significant KS, a mastoidectomy with anterosuperior tympanostomy is advised as a solution. There is little evidence to support the theory that the size of KS is related to mastoid pneumatization, however, it may coincide with other structural abnormalities like an undeveloped mastoid or a sigmoid sinus near the ear canal. About 6.58 percent of healthy ears have KS, but in ears with retraction pockets or tympanic membrane adhesion, its frequency rises to 30.4 percent, and in cases of chronic otitis media without retraction pockets, it is 17.4 percent. Additionally, KS has been documented in 25 percent to 33 percent of all temporal bones and in 24 percent to 28 percent of operated temporal bones. According to certain beliefs, an expanding cholesteatoma may interact with enzymes, harming KS and changing ear ventilation, which in turn may affect disorders such as tympanosclerosis.
KS can obstruct middle ear ventilation channels in tympanosclerosis with adherent otitis media, leading to long-term inflammation. Adults are more likely to get KS, which can occasionally be linked to persistent otitis media, especially when squamosal illness is present. Studies indicate that by preventing middle ear airflow, KS may contribute to the development of chronic otitis media.
What Are the Best Imaging Techniques for Visualizing Korners Septum?
The best methods for imaging Korner's septum (KS) in the temporal bone are cone-beam computed tomography (CBCT) and high-resolution computed tomography (HRCT). HRCT displays KS as a bone thickening in both the axial and coronal sections and normally entails data collection in the axial plane parallel to the lateral semicircular canal. The superior mastoid cells, the stylomastoid foramen, and the external auditory canal's upper wall are all included in the imaging field. HRCT scans with a slice thickness of 1.0 to 1.25 mm (millimeter) are performed in a soft tissue window for soft tissue evaluation, and a bone window with a slice thickness of 0.4 to 0.6 mm is used to rebuild the temporal bones. Contrast agents are typically not used.
CBCT is starting to replace conventional CT scanning. It uses a revolving gantry on which an X-ray tube and detector are fixed. A cone-shaped X-ray beam that travels through the temporal bone reaches a 2D (two-dimensional) X-ray detector. A single 360° gantry rotation obtains a volumetric data set, enabling further multiplanar reconstructions using specialist software with a slice thickness of 0.3 to 1 mm.
Conclusion
The function of Korner's septum (KS), specifically the squamosal form, in chronic otitis media (COM) is highlighted in this study. Although the precise causes of KS development during pregnancy are unknown, research points to KS's potential to raise the incidence of tympanosclerosis, cholesteatoma, retraction pockets, and inflammatory middle ear conditions by reducing ventilation. Precise pre-operative imaging with HRCT or CBCT is essential to locate and evaluate KS. More research is required to fully understand its effect on middle ear inflammation.
