title: Preliminary experience with beta-tricalcium phosphate for use in mastoid cavity obliteration after mastoidectomy.
abstract: OBJECTIVE
  To examine the efficacy and safety of mastoid cavity obliteration using highly purified beta-tricalcium phosphate (beta-TCP) after mastoidectomy in middle ear surgery.
  
  
  METHODS
  Thirteen patients with cholesteatoma invading the mastoid cavity or showing severe pathologic changes in the mastoid cavity.
  
  
  METHODS
  Twelve patients underwent mastoid obliteration with highly purified beta-TCP during the first- and/or second-stage operation of a 2-stage canal-up operation: 5 patients during the first and second stages, and 7 patients during the second stage only. One patient with cholesteatoma underwent mastoid obliteration with highly purified beta-TCP during a 1-stage canal-up operation. In total, beta-TCP was applied in 18 ear operations.
  
  
  METHODS
  All patients underwent multislice computed tomography (CT) before and after surgery to assess the condition of the middle ear. The amount of residual beta-TCP granules in the mastoid cavity was assessed using the following granular shadow grading scale: Grade 0, no granular shadow in the mastoid cavity; Grade 1, residual granular shadows in part of the mastoid cavity; and Grade 2, granular shadows in most of the mastoid cavity. To assess any harmful effect of beta-TCP implanted in the mastoid cavity, continuous postoperative discharge and delayed wound healing were recorded. In addition, the bone conduction threshold was assessed using pure-tone audiometry, and the patients were asked whether they experienced vertigo or dizziness during the postoperative follow-up.
  
  
  RESULTS
  All the patients who underwent multislice CT less than 11.4 months after mastoid cavity obliteration with beta-TCP were Grade 2 on the granular shadow grading scale, whereas all those who underwent multislice CT more than 53.8 months after mastoid obliteration were Grade 0. No patient had continuous postoperative discharge, delayed wound healing, or extrusion of beta-TCP granules. No patient showed deterioration of the bone conduction threshold more than 10 dB after mastoid cavity obliteration with highly purified beta-TCP or complained of postoperative vertigo or dizziness.
  
  
  CONCLUSIONS
  Highly purified beta-TCP may be safe and reliable for mastoid obliteration. Highly purified beta-TCP may also be useful in other surgical procedures, including posterior wall reconstruction of the external auditory canal and scutum plasty.
authors: Department of Otolaryngology-Head and Neck Surgery, Kumamoto University School of Medicine, Kumamoto, Japan. mioda@gpo.kumamoto-u.ac.jp
authors: Ryosei
authors: R
authors: Minoda
authors: Momoko
authors: M
authors: Hayashida
authors: Masako
authors: M
authors: Masuda
authors: Eiji
authors: E
authors: Yumoto
mesh_terms: D001844:Bone Conduction / Q000187:drug effects; D002130:Calcium Phosphates / Q000627:therapeutic use*; D018424:Cholesteatoma, Middle Ear / Q000150:complications / Q000601:surgery*; D004432:Ear, Middle / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008416:Mastoid / Q000473:pathology / Q000601:surgery*; D013506:Otologic Surgical Procedures / Q000009:adverse effects*; D011183:Postoperative Complications / Q000188:drug therapy* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014433:Tympanoplasty
chemical_list: D002130:Calcium Phosphates; C485817:beta-tricalcium phosphate