bubble_chart Overview

There is a continuous mucous membrane between the middle ear and the mastoid. After suppurative infection in the middle ear, the mastoid mucous membrane also exhibits corresponding inflammatory reactions, initially presenting as catarrhal inflammation, with possible grade I tenderness in the mastoid region. Once the tympanic membrane perforates and pus drains, the mastoid inflammatory reaction promptly subsides. If pus drainage is inadequate or if the infection is caused by highly virulent type III pneumococci, bone destruction may occur, leading to mucosal edema, hemorrhage, necrosis, and suppuration in the mastoid air cells, resulting in acute suppurative mastoiditis. This condition is essentially a sequel to acute otitis media and should be referred to as acute suppurative otomastoiditis.

bubble_chart Pathological Changes

The degree of mastoid qi transformation varies, and its manifestations after inflammation also differ.

(1) Qi transformation mastoid: The bony septa of the small cells are very thin and prone to necrosis and fusion, forming large cavities, known as coalescent mastoiditis. If infected by highly virulent hemolytic streptococci or hemolytic influenza common cold bacilli, it often leads to vascular embolism of the mucous membrane, hemorrhage, and necrosis. The small cells become filled with bloody secretions, but the bony walls remain intact, a condition referred to as hemorrhagic mastoiditis.

(2) Interstitial type (diploic type) mastoid: There are few small cells, and the cortex is thicker with a marrow structure. Infection results in osteomyelitis, and the inflammation persists for a long time. Due to poor drainage, it is prone to complicating intracranial infections.

(3) Sclerotic type (compact type) mastoid: The small cells are very small and have an ivory-like structure. After infection, drainage is difficult, and bone destruction is unlikely to occur. This often leads to hyperplasia of the mucous membrane tissue, congestion and necrosis of the flaccid part of the tympanic membrane, and the formation of cholesteatoma.

bubble_chart Clinical Manifestations

Increased pus discharge after otitis media, redness, swelling, and tenderness in the retroauricular sulcus, the auricle is pushed forward, severe pain when pressing the McEwen's triangle behind the external auditory canal, congestion and edema in the flaccid part of the tympanic membrane. Tinnitus and deafness show no improvement.

bubble_chart Diagnosis

When symptoms worsen after perforation and pus discharge from the tympanic membrane in otitis media, it is often due to acute infection. Mastoid X-ray or CT scans may reveal opacity or bone destruction in the mastoid region.

bubble_chart Treatment Measures

The treatment during the acute phase is the same as for acute suppurative otitis media. If there is no improvement after one month of reasonable treatment, or if high fever persists, postauricular redness and swelling occurs, the posterior wall of the external auditory canal collapses, or bone destruction is observed on mastoid X-rays, a simple mastoidectomy should be performed.

**Surgical Method:** General anesthesia is used for children, while local anesthesia may suffice for adults. A 1% procaine or lidocaine solution with a small amount of 1% epinephrine is employed. A retrobulbar needle is used to perform a ring infiltration anesthesia along the osteocartilaginous junction inside the ear canal opening. Then, a No. 7 needle is used for subcutaneous infiltration anesthesia in the postauricular mastoid region. A curved incision is made behind the ear, starting 0.5 cm above the auricle and extending about 1.5 cm behind the ear groove down to the mastoid tip. In children, the mastoid is underdeveloped, so the incision should not be too anterior or too low to avoid injuring the facial nerve. The bone membrane is incised, and the mastoid is exposed. Using a chisel or electric drill, the mastoid is opened through the cribriform area posterior to the posterior-superior spine of the external auditory canal. This area corresponds to Macewen’s triangle, with its apex pointing posteriorly and superiorly, bounded superiorly by the posterior root of the zygomatic arch (extending horizontally backward), anteriorly and inferiorly by the posterior-superior spine of the external auditory canal, and posteriorly by the posterior edge of the external auditory canal opening. From here, the bone is chiseled forward and medially parallel to the posterior wall of the external auditory canal, reaching a depth of about 1 cm in adults or 2–4 mm in children to enter the mastoid antrum. All diseased cells, mucous membranes, granulation tissue, and sequestra are thoroughly removed, especially the granulation tissue at the aditus ad antrum, to establish drainage. However, the ossicular chain and tympanic structures should not be disturbed, and the skin of the external auditory canal should not be stripped to avoid hearing impairment or the formation of fistulas or stenosis. Care must be taken not to injure the semicircular canals or the mastoid segment of the facial nerve when working anteriorly and inferiorly. The completed mastoid cavity should be a healthy, smooth bony space, bounded anteriorly by the aditus ad antrum and the posterior wall of the external auditory canal, superiorly by the tegmen plate, and posteriorly by the sigmoid sinus plate. If intracranial complications are suspected, the tegmen plate and sigmoid sinus plate should be slightly opened to check for granulation tissue or abscesses. After surgery, the cavity is irrigated and hemostasis is achieved. The wound is packed with iodoform gauze, and the incision is sutured in layers, leaving the tail end of the gauze outside the cavity for easy removal. The gauze is removed 5–7 days postoperatively, and dressings are changed every 2–3 days. Systemic broad-spectrum antibiotics are continued. Within 1–2 months, the mastoid cavity will be filled with blood clots and granulation tissue, and the middle ear infection is expected to resolve.