Post-op Complications Flashcards
(25 cards)
Over the years, have surgical techniques and device technology drastically improved?
Yes
Devices have improved due to the efforts of device manufacturers
Cochlear implant surgery is regarded as a safe procedure With less than 1.6% complication rates
Can complications still happen?
Yes
Can be due to the operation complexity, the skill of the surgical team, and the inherent risks of the procedure itself
What are some early complications of CI surgery?
Facial nerve injury
Alteration of taste
Infection
Dizziness
Wound dehiscence
Flap necrosis
Early device failure
CSF leak
What causes wound dehiscence/flap necrosis?
Due to aggressive thinning of flap - most serious complication and requires device removal
*flap necrosis is more serious bc the skin around the area may not heal even after device is removed
How common are CSF leaks after CI surgery?
Not that common, incidence between 1 and 5%
Reported more frequently in ears with inner ear malformations
Occurs frequently at the time of drilling tie down holes
Can also occur after opening of scala tympani in case of modiolar defect (common cavity deformity)
Controlled by packing the common cavity with muscle or a watertight seal around the entrance of cochlear implant array
If still not controlled – Ear is closed by plugging the eustachian tube, filling the middle ear & mastoid with fat and oversewing the Extn Auditory canal
What are some examples of late complications?
Extrusion/exposure of device
Displacement of electrodes
Late device failure
Otitis media
Meningitis
Are CI recipients at a high risk of developing pneumococcal meningitis?
Yes
Good to check for fluid at the time of follow-up
It is recommended by the CDC that pneumococcal conjugate and polysaccharide vaccines be administered to children who have or are candidates for CIs
What are the main pathological issues that can result from the implant?
Electrode insertion trauma and the histopathological consequences
Biocompatibility of the device
Infection in the ME and the risk of it spreading to the cochlea and meninges
Is there typically inflammation after electrode insertion ?
Yes
Response by the tissues of the body to an agent that is damaging such as physical insults, chemicals, and toxins produced by bacteria
Initially there is an immediate response or acute phase (expected response)
If agent persists, the inflammatory response will become subacute and pass into a chronic phase (can result in the development of fibrosis and calcification and even new bone formation)
What is the proposed grading scale for evaluating intracochlear trauma from the electrode array?
Eshraghi et al.
Stage 0 - no observable trauma
Stage 1 - Elevation of the basilar membrane
Stage 2 - Rupture of the basilar membrane
Stage 3 - Electrode in scala vestibuli
Stage 4 - Severe trauma such as fracture of the osseous spiral lamina or modiolus or tear of stria vascularis
What are the major cochlear structures that may be susceptible to injury during surgery?
Lateral wall (spiral ligament and stria vascularis)
Basilar membrane and cochlear duct
Osseous spiral lamina and the modiolus
What is one of the most commonly reported types of insertional damage?
Lateral wall trauma
May occur in several ways and can be due to impingement by an electrode tip or to pressure exerted by the body of the silicone carriers as it contacts the area where the basilar membrane joins the spiral ligament alone or may also include the basilar membrane and osseous spiral lamina
When the basilar membrane is involved, it is often torn at its attachment to the lateral wall and there may or may not be penetration of the electrode into scala media (and the mixing of perilymph and endolymph - toxic)
Do they make the electrodes to be close to the modiolus?
Yes, so they design it to be that way
But this might also contribute to more damage
Can forceful or fast insertion cause osseous lamina fracture?
Yes
Osseous lamina fracture would sever the dendrites of spiral ganglion cells eventually leading to ganglion cell degeneration in the affected area
Neural survival is limited in that area
What can be the reaction of the body to implanted materials?
Inflammation, a foreign body reaction, encapsulation, or hypersensitivity
The response may be the result of the toxic chemicals from the device or just the physical shape and dimensions leading to foreign body reaction and encapsulation
Can tissue reactions to implanted materials vary?
Yes
From toxic reactions (inflammation and infection occur as a result of degradation of the implanted material and/or implant orientation or geometry)
Vital reactions where the body detects the foreign object and incorporates it into the body by covering it in a vascularized fibrous scar tissue encapsulation
Can bacterial meningitis be secondary to otitis media or an open head injury and surgery?
Yes
Is trauma to the mastoid area and inner ear malformations highly correlated with major delayed complications and early minor complications?
Yes
Is facial nerve palsy or paralysis considered a major complication?
Yes
What are the rates of minor and major complications?
An initial survey of 2751 implant performed at multiple centers in the United States revealed the rate of major and minor complications to be 8% and 4.3% respectively
A follow up survey in 459 patients published in 1991 revealed complications rate of 5% and 7% perhaps showing a decrease in the rate of major complications over time for a similar group of surgeons using a single device
What are other risks for CI implantation?
Tinnitus and vertigo (sporadic episodes of dizziness)
Altered taste sensations (affected patients can develop an unusual metallic taste in their mouth - chorda tympani involved; may go away with time)
CSF leak (1% of patients; additional surgery may be required to repair leakage)
When does the implant need to be removed?
If the skin flap is infected
If the body rejects in the implant
Head trauma
The implant receiver is extruded
The electrode array is damaged, migrates out of place or the electrodes were not put in right
Malfunctioning of the implant
What is a soft failure?
Easiest to identify
Cochlear Americas - patients hearing performance has noticeably decreased but the implant integrity testing shows the implant is functioning as normal
AB - device malfunction is suspected but cannot be confirmed using currently available tools; may be suspected when there is a lack or decline of hearing performance, popping sounds or intermittent hearing with CI
*uncommon occurrence in which a device malfunction is suspected but cannot be proven
How do you diagnose a soft failure?
Begins with awareness of common presentations including declining performance, aversive symptoms such as a popping or shocking sensation or intermittent function
The working diagnosis of soft failure is arrived at after painstaking evaluation by the cochlear implant team, manufacturer, and patient
The working diagnosis can only be confirmed by removal, examination of the suspect device, and identification of a failure mechanism
Reimplantation of another device with subsequent alleviation of symptoms strongly supports the diagnosis, but cannot conclusively confirm a device malfunction
