Spontaneous Tegmen Tympani Dehiscence: Causes and Treatment of Conductive Hearing Loss

Abstract

Objective:Conductive hearing loss (CHL) commonly arises in patients with spontaneous dehiscence of the tegmen of the temporal bone with meningoencephalocele (SME). The aim of this study was to further investigate 1) the potential mechanisms for CHL in this setting; 2) hearing outcomes following surgery to address SME, and 3) the possible causes of persistent CHL following surgery.Study Design:Retrospective case review.Setting:Tertiary referral center.Patients and Intervention:Seven patients (six female; nine ears) who underwent middle cranial fossa repair of SME and were found to have a tegmen tympani dehiscence from October 2010 to September 2014 were included in the study.Main Outcome Measure(s):Pre- and postoperative pure-tone audiometry.Results:Eight of nine ears (89%) had audiometric hearing loss at presentation. Seven ears (78%) had an air bone gap of ≥15 dB; all of these had an encephalocele traversing the tegmen tympani defect, four had a middle ear effusion, and three had a simultaneous superior semicircular canal dehiscence (SSCCD). The CHL resolved postoperatively in four of seven ears. Two of the three ears with persistent CHL had SSCCD. Attic ossicular fixation was identified in the other patient and the CHL resolved after ossiculoplasty.Conclusions:CHL associated with SME can be attributed preoperatively to ossicular chain fixation and synchronous SSCCD as well as the more commonly cited cerebrospinal fluid effusion and prolapse of meningoencephalocele onto the ossicular chain. Persistent postoperative CHL can also occur due to SSCCD and ossicular fixation by adhesions.

Asociación entre dehiscencia del canal semicircular superior y dehiscencia del tegmen tympani. Revisión narrativa cronológica

“…Heywoody cols. informaron la existencia, en 7 pacientes intervenidos quirúrgicamente de su dehiscencia del tegmen, la presencia en 3 de ellos de una dehiscencia del canal semicircular superior asociada (43%) 29 . Castellucci y cols.…”

Fibrin Glue–Coated Collagen Complex Patch: A Novel Material for Surgical Repair of Spontaneous Temporal Bone Cerebrospinal Fluid Leak and Encephalocele

“…Reconstruction of the bony skull base defect has been reported using autologous tissues including cortical bone, cartilage, bone dust, fat, and muscle (18). Allografts such as porous polyethylene (19), titanium mesh (1), and hydroxyapatite cement (3,5,(7)(8)(9)(10)19,20) have also been reported, although some studies have reported increased rates of postoperative infection with allografts (1,19).…”

“…Multiple reports in the literature have suggested that SSCD raises the risk of vestibular injury and resultant sensorineural hearing loss in MF craniotomy (1,10), with some advocating for intraoperative ABR monitoring when SSCD is suspected on preoperative imaging (1). Routine superior canal resurfacing has also been described (3,8) to prevent sensorineural hearing loss, although the practice is not uniformly successful. Manipulation of the ossicles has also been theorized to cause inner ear trauma and postoperative sensorineural hearing loss (8,10).…”

“…The approach has also been used for recurrence after previous TM repair (6,21). Disadvantages of the MF approach include intracranial surgery and the risk of facial nerve injury at the geniculate ganglion, which has been reported to be dehiscent in the MF floor in approximately 33% of patients (3) with spontaneous tegmen dehiscence. Concomitant superior semicircular canal dehiscence has also been reported in 12.5 to 33% of this patient population (3,5,8,10) and may predispose a patient undergoing MFC to vestibular injury and sensorineural hearing loss.…”

“…When there is a defect of the adjacent dura, a cerebrospinal fluid (CSF) leak occurs. Temporal bone CSF leaks typically present with fluid in the middle ear, either as otorrhea or as effusion, and conductive hearing loss (1)(2)(3)(4)(5)(6). They can be difficult to localize and repair.…”