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Retraction Pockets

Retraction pockets

A retraction pocket is a localized area of indrawing (or invagination) of tympanic membrane into the middle ear or attic. The initial cause of retraction pockets is recurrent or chronic negative pressure in the middle ear, due to dysfunction of the eustachian tube. Collagenase and elastase enzymes secreted by inflammatory cells during acute otitis media or serous otitis media can destroy the middle fibrous layer of the tympanic membrane making it atrophic and more prone to retraction.

Retraction pockets can resolve automatically or they can stay safe & stable for a long period of time or can become unstable leading to invasion of middle ear cleft and formation of cholesteatoma in later stages.

Common sites of retraction pockets:

  1. Pars flaccida. The pars flaccida is actually thicker than the pars tensa, but it is the weakest part of the TM due to thinner less-organized collagen fibres which are loosely arranged in lamina propria. There is also absence of annulus sulcus, which stabilizes the insertion of the TM to the surrounding bone.
  2. Posterosuperior quadrant of the pars tensa. It has thinner, more sparsely distributed collagen and is highly vascularised and thus more prone to inflammatory reactions, which causes breakdown of collagen skeleton due to secretion of collagenase enzyme. Because of this TM becomes atrophic and susceptible to retraction.

Types of retraction pockets:

  1. Shallow pockets. The extent of pocket is visible on examination. These pockets are usually nonprogressive and self-cleaning pockets.
  2. Deep pockets. The extent of pocket is not visible on examination. It tends to collect squamous keratin debris and becomes a cyst. When infected, these cysts drain and granulation tissue develops around the sac, causing bone erosion and possible complications.

Classification of retraction pockets.

1. Stages of retraction of Pars Tensa by Sadé and Berco. 

  • Grade 1. Tympanic membrane is slightly retracted but does not contact the incus. There is loss of light reflex.
  • Grade 2. Tympanic membrane is retracted on long process of incus (adhesion is called tympanoincudopexy) or contacting the stapes (adhesion is called tympanostapediopexy).
  • Grade 3. Also called middle ear atelectasis. Tympanic membrane comes to lie on the promontory but not adhered. It moves on Valsalva maneuverer or suction tip.
  • Grade 4. Also called adhesive otitis media. Tympanic membrane is adhered to the promontory. It does not moves on Valsalva maneuverer or suction tip.
  • Grade 5. Grade III or IV with perforation in the tympanic membrane.
Otoscopy pictures of stages of pars tensa retractions: (Fibrous annulus (FA), Cone of light (COL), Lateral process of malleus (LP), Handle of malleus (HOM), Long process incus (IN), Incudostapedial joint (ISJ), Stapedius tendon (St), Round window (RW), Part of horizontal facial nerve (FN), Promontory (Pr), Stapes suprastructure (SS), Stapedius tendon (St), Tympanic membrane is adhered to promontory (Pm), Posterior malleolar fold (PMF))

 

2. Stages of retraction of Pars Flaccida by Tos et al. 

  • Grade 1. The pars flaccida is dimpled and more retracted than normal but not adherent to the malleus neck.
  • Grade 2. The retraction is adherent to the neck of the malleus.
  • Grade 3. Partial erosion of the bony attic wall with fundus visible.
  • Grade 4. Definitive erosion of bony attic wall, unable to visualize its fundus.

Clinical features of retraction pockets: There may be persistent ear discharge, hearing loss, and cholesteatoma formation. Earache and dizziness are very rare symptoms

Management:

  • Shallow pockets. Observation with periodic microscopic examination and regular suctioning and cleaning of debris or cerumen. Encourage auto inflation and look for contributing factor (adenoid disease, allergy and GERD) for eustachian tube dysfunction. Placement is tympanostomy tube or simple excision of damaged TM can be done if the pocket is progressive.
  • Deep pockets. Demands urgent surgical mastoid exploration under general anaesthesia for correction/repair of the irreversible pathologic processes.

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Learning resources.

  • Scott-Brown. Textbook of Otorhinolaryngology Head and Neck Surgery.
  • Glasscock-Shambaugh. Textbook of  Surgery of the Ear.
  • Hans Behrbohm, Tadeus Nawka. Textbook of Ear, Nose, and Throat Diseases with Head and Neck Surgery.
  • Salah Mansour, Jacques Magnan, Karen Nicolas, Hassan Haidar. Textbook of Middle Ear Diseases Advances in Diagnosis and Management.
  • Gordon B. Hughes, Myles L. Pensak, H. B. Broidy. Textbook of Clinical Otology.
  • Mario Sanna. Textbook of Color Atlas of Endo-Otoscopy Examination–Diagnosis–Treatment.

Author:

Dr. Rahul Kumar Bagla
MS & Fellow Rhinoplasty & Facial Plastic Surgery.
Associate Professor & Head
GIMS, Greater Noida, India
msrahulbagla@gmail.com

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