and Pu Dai5
(5)
Department of Otolaryngology Head and Neck Surgery, Fuzhou General Hospital of Nanjing Command, PLA, Fuzhou, 350025, China
Indications
- 1.
Stapedial Otosclerosis, air conduction hearing levels (Pure Tone threshold on average) >30 dB with conductive hearing loss >15 dB.
- 2.
Late stage otosclerosis.
- 3.
Fixation of the footplate by tympanosclerosis with an intact or repaired tympanic membrane.
- 4.
Congenital anomalies with fixation of the footplate.
Contraindications
- 1.
Infection in the external auditory canal or middle ear.
- 2.
Perforated tympanic membrane.
- 3.
High-resolution computer tomography scan showing absence of the bony partition between the fundus of the internal auditory canal and the vestibule or the cochlea.
- 4.
Dysfunction of the Eustachian tube.
- 5.
Gusher in the contralateral ear.
- 6.
Advanced cochlear otosclerosis.
Operative Procedures
- 1.
Make the first incision: Cut the skin, subcutaneous tissue, and periosteum of the external auditory canal (EAC) at the anterior notch of the ear laterally, and extend the incision medially, to the junction of cartilage and bone.
- 2.
Make the second incision: Begin from the 6 o’clock position, 5–6 mm lateral to the fibrous annulus, along the posterior meatal wall in an ascending spiral fashion, to meet the first incision at its medial end.
- 3.
Elevate the tympanomeatal flap: The meatal flap is elevated to the tympanic sulcus with a blunt elevator and the fibrous annulus is then elevated from the sulcus with the same instrument. The tympanomeatal flap is pushed forward over the edge of bony sulcus. Special care should be taken to avoid tearing the flap.
- 4.
To gain adequate exposure to the oval window and stapes, 2–4 mm of postero-superior bony canal rim must be removed with an angled middle ear curette or chisel, taking care not to injure the surrounding structures. Bone should be removed until the facial nerve, footplate of stapes, stapedius tendon, and pyramidal eminence can be seen.
- 5.
Evaluate the mobility of each of the three ossicles.
- 6.
Measure the distance between the undersurface of the long process of the incus and the footplate.
- 7.
Cut the stapedius tendon.
- 8.
Separate the incudostapedial joint.
- 9.
Removal of the stapes: The stapes superstructure is down-fractured toward the promontory and taken out, the footplate is fenestrated in its midportion. A fine hook is used to remove the entire footplate (total stapedectomy) or the anterior half of the footplate (partial stapedectomy).
- 10.
Placement of prosthesis: The crook of the prosthesis is adequately crimped onto the long process of the incus with a crimper. The prosthesis should pass into the vestibule for about 0.25 mm, not more than 0.5 mm.
- 11.
A small piece of fat is applied to seal the opening of the oval window around the prosthesis.
- 12.
Return the tympanomeatal flap to its original position. Rinne’s test is performed to assess the hearing gain in patients where local anesthesia has been used. If Rinne’s test is negative, the position of the prosthesis should be re-checked and adjusted if necessary.
- 13.
The EAC is packed with gelatin sponge and iodoform gauze, suture the first incision.
Special Comments
- 1.
Expose the oval window, long process of the incus, and facial canal adequately.
- 2.
The mobility of all three ossicles should be assessed.
- 3.
Pay attention to the integrity of the facial canal and its relationship with the oval window.
- 4.
Avoid applying epinephrine cotton ball for hemostasis in tympanic cavity after opening of the oval window.
- 5.
Avoid using suction directly over the opening of the oval window.
- 6.
The mucosa of the oval window niche should be removed before sealing the oval window with fat.
- 7.
The length of the prosthesis should be long enough for its medial end to enter the perilymph fluid without contacting the membranous labyrinth.
- 8.
The crook of the prosthesis should be crimped on the long process of the incus adequately to avoid incus erosion.
- 9.
Bed rest for 3 days after operation, avoiding straining and nose blowing.
- 10.
Avoid air travel for at least 1 month to reduce the risk of significant changes in middle ear pressure and displacement of the tympanic membrane and prosthesis.
Complications
- 1.
Sensorineural hearing loss: It is usually irreversible. Trauma to the inner ear should be avoided during operation.
- 2.
Vertigo or dizziness: This symptom is not common after surgery, but may be due to loss of perilymph fluid, surgical trauma, protrusion of prosthesis to the utricle, or serous labyrinthitis.
- 3.
Loss or distortion of taste affecting the tongue on the side of the operation: This symptom is caused by severance of or trauma to the chorda tympani nerve. Care should be taken not to injure the chorda tympani when removing the posterosuperior bony canal rim,
- 4.
Facial paralysis: resulting from injury to the facial nerve. A dehiscent, prolapsed facial nerve protruding over the footplate is prone to injury. It is very important to obtain full exposure of facial canal and identify any abnormal course of facial nerve and its canal.
- 5.
Perilymph fistula: resulting from failure to seal the oval window. The mucosa of the oval window niche should be removed before sealing the window with fat or fascia.
- 6.
Tympanic membrane perforation: due to failure to effectively repair a torn tympanic membrane. Special care should be take not to tear the tympanic membrane when elevating the annulus. If a tear does occur, it can be repaired with a piece of fascia or fat.
- 7.
Prosthesis displacement: This is usually caused by a short prosthesis slipping out of the oval window.
- 8.
Distortion of sense of voice may be experienced by vocal musicians after the operation.
- 9.
Labyrinthitis: This may be caused by a failure to maintain proper asepsis during the operation and failure to seal the oval window effectively.
Surgery 1: Total Stapedectomy and Piston Prosthesis (artificial stapes) Implantation
Fig. 4.1
Make the first incision
The first skin incision starts from the 12 o’clock position of EAC and is carried down to the bone. It is extended laterally between the tragus and the root of helix for about 0.5–1.0 cm and medially to a point 6–8 mm lateral to the pars flaccida membrane
Fig. 4.2
Make the second incision and elevate the meatal flap
Make the second incision to connect the 6 o’clock point, running 5–6 mm lateral to the annulus, and the medial end of the first incision. The meatal flap is elevated with a micro-elevator to the posterior sulcus and notch of Rivinus. The skin of the bony external auditory canal can be very thin in patients with otosclerosis. A small suction tube is used, avoiding tearing of the flap by not sucking directly on it. Remove the overhanging suprameatal spine to get better exposure using a diamond burr or chisel if necessary
Fig. 4.3
Enter the tympanic cavity
The fibrous annulus is elevated from the tympanic sulcus from the 12 to 6 o’clock position with a blunt elevator. The tympanomeatal flap is pushed forward to expose the tympanic cavity. Care should be taken not to tear the flap
Fig. 4.4
Exposure of the oval window
2–4 mm of postero-superior bony canal rim is removed with an angled middle ear curette or chisel to fully expose of the incudostapedial joint, the long process of the incus, the stapedius tendon, the anterior and posterior crura, the oval window, and the horizontal segment of the facial nerve. The mobility of the three ossicles is evaluated. Care is taken to assess whether the facial nerve has an aberrant course or if the nerve is dehiscent and overhanging too much to allow the procedure to continue
Fig. 4.5
Total stapedectomy
After confirming the mobility of the incus and malleus, the stapes is removed. The chorda tympani nerve is pushed forward and downward, the distance between the undersurface of the long process of the incus and the footplate is measured with a measuring rod, the stapes tendon is cut with delicate scissors, the incudostapedial joint is disconnected with a micro hook, and the stapes is mobilized and taken out totally
Fig. 4.6
Seal the oval window temporarily with a piece of fat
After removal of the stapes, the opening of the oval window is immediately sealed with an adequately sized piece of fat to prevent blood from entering the labyrinth and loss of perilymphatic fluid. After opening the oval window, a saline (rather than adrenaline) soaked cotton ball is applied to stop bleeding. Meanwhile, the prosthesis is cut to suitable length based on the measurement of the distance between the undersurface of the long process of the incus and the footplate
Fig. 4.7
Get ready to place the prosthesis
Take the fat out gently in order not to interfere with the perilymphatic space. The opening of the oval window looks light blue and clear. Direct suction in the opening of the oval window must be prohibited to avoid loss of the perilymph and damage to the inner ear
Fig. 4.8
Placement of the prosthesis
The wire of the prosthesis is hooked over to the long process of the incus at the junction of its middle and lower thirds. The medial end of the prosthesis is placed at the center of the oval window. The wire is fixed properly with a crimper. One or two adequate sized pieces of fat are applied to seal the oval window
Fig. 4.9
Replace the tympanomeatal flap in its original position
Replace the tympanomeatal flap in its original position. Rinne’s test is performed in patients under local anesthesia to assess the hearing gain. If Rinne’s test is negative, the mobility of malleus and incus and position of the prosthesis should be checked again
Fig. 4.10
Packing of the external auditory canal and suturing the incision
After re-positioning of the flap, the external auditory canal is packed with gelatin sponge and iodoform gauze. After loosening the self-retaining retractor, there may be some bleeding, which can be stopped by bipolar coagulation. The first incision is sutured
Surgery 2: Total Stapedectomy and Implantation of Piston Prosthesis
Fig. 4.11
Measuring the distance between the footplate and the undersurface of the long process of the incus
Measure the distance between the footplate and the undersurface of the long process of the incus with the measuring rod. The distance is about 4 mm in this case. This step should be performed before removal of the stapes in case of alteration of the position of the incus
Fig. 4.12
Disconnection of the incudostapedial joint
After the stapes tendon is cut with delicate scissors, a micro hook is inserted into the incudostapedial joint space to disconnect the joint by gently moving the micro hook in a direction parallel with the articular surface. Care should be taken not to displace the incus
Fig. 4.13
Removal of the superstructure of the stapes
Push the anterior and posterior stapes crura down toward the promontory with a right angled microhook to fracture them or cut them with a set of stapes scissors. Do not push the superstructure of stapes upward in case of injury of the facial nerve. Then remove the superstructure and make a fenestration in the center of the footplate. Use micro hook to take the footplate out
Fig. 4.14
Placement of the prosthesis
The wire of the prosthesis is hooked over to the long process of the incus at the junction of its middle and lower thirds. The medial end of the prosthesis is placed at the center of the oval window. The wire is fixed properly to the incus with a crimper. One or two adequate sized pieces of fat are applied to seal the oval window tightly
Surgery 3: Partial Stapedectomy and Implantation of Piston Prosthesis
Fig. 4.15
Exposure of the oval window and the long process of the incus
2–4 mm of posterior superior bony canal rim is removed with an angled middle ear curette or chisel to fully expose of the long process of the incus, stapes tendon, the oval window, and the horizontal segment of the facial nerve. The mobility of the three ossicles is evaluated. Slippage of the chisel may damage important structures such as facial nerve, incus, stapes and inner ear
Fig. 4.16
The oval window and stapes (with high magnification)
Fully expose the incudostapedial joint, the long process of the incus, stapes tendon, anterior and posterior crura, the oval window, and the horizontal segment of the facial nerve. The footplate looks lustrous. There is a relatively large vessel on the footplate. The vessel should be treated before fenestration of the footplate using micro-bipolar coagulation or by applying an adrenaline cotton ball after removal of the mucosa of the oval window
Fig. 4.17
Remove part of the footplate
After taking out the superstructure of the stapes, a hole is made in the center of the footplate with a three-sided perforator or with a micro bur. Then enlarge the hole with a special micro hook to remove the central part of the footplate
Fig. 4.18
Placement of the prosthesis
The medial end of the prosthesis makes contact with the perilymph through the opening of the footplate. The prosthesis should extend into the vestibule for about 0.25 mm, and not more than 0.5 mm. The wire of the prosthesis is hooked over the long process of the incus and fixed to it properly with a crimper. An adequate sized piece of fat is applied to seal the opening of the footplate
Fig. 4.19
Replace the meatal flap
Replace the meatal flap in its original position. Check the integrity of the tympanic membrane. The external auditory canal is packed with gelatin sponge and iodoform gauze and the first incision is sutured
Fenestration of Stapes and Implantation of Stapes Prosthesis
Fei Yu6 and Pu Dai6
(6)
Department of Otolarygngology Head and Neck Surgery, PLA General Hospital, Beijing, 100853, China
Indications
- 1.
Stapedial otosclerosis, air conduction hearing levels (Pure Tone threshold on average) >30 dB with conductive hearing loss >15 dB.
- 2.
Tympanosclerosis or adhesive otitis media with fixation of stapes but good Eustachian tube function.
- 3.
Congenital stapes malformation.
- 4.
Age range of 5–80 years.
Contraindications
- 1.
Poor general health.
- 2.
Sensorineural hearing loss of a moderate or worse degree.
- 3.
Conductive hearing loss less than 15 dB.
- 4.
Dysfunction of Eustachian tube.
- 5.
Acute upper respiratory infection.
- 6.
Small children or elderly patients.
- 7.
Active menstruation in women
- 8.
Certain professions such as pilots or those who work at heights.
Operative Procedures
- 1.
Endaural incision. First, a longitudinal incision should be made anterior to the root of the helix toward the junction of bone and cartilage in the upper part of the external auditory canal (EAC). A second circumferential incision is made under the microscope from the 6 o’clock position inferiorly, 4 mm posterior to the tympanic ring and extending superiorly to meet the first incision.
- 2.
Elevation of tympano-meatal flap. Dissection should be across a wide front from lateral to medial, elevating the flap from the bony canal wall and taking care to keep it intact. Hemostasis can be achieved with adrenalin soaked cotton or bipolar coagulation. The superior meatal spine can be curetted away if necessary.
- 3.
Entering the middle ear. Elevation of the flap continues to the tympanic ring, where the annulus is elevated with vertical dissection to enter the middle ear.
- 4.
Explosion of middle ear cavity. Part of the postero-superior wall of the EAC may need to be curetted to provide good visualization of the incus long process, the stapes, the stapedius tendon, the pyramidal eminence, and the horizontal part of facial nerve. The ossicles are then assessed for shape (in case of congenital malformation) and mobility. In otosclerosis, the malleus and incus are normally mobile but the stapes footplate fixed.
- 5.
Removal of stapes superstructure. The incudostapedial joint are separated and the stapedius tendon is severed close to the pyramidal eminence. The anterior and posterior crura of the stapes are down fractured and the superstructure is removed.
- 6.
Perforation of stapes footplate. A pinhole of about 1 mm diameter is made in the center of the stapes footplate using a mini drill, a triangle shaped perforator or a laser, and the perilymph is visible.
- 7.
Setting prosthesis. A Teflon and wire prosthesis can be used. The Teflon end can be trimmed for the appropriate overall length (usually between 3.75 and 4.5 mm). The Teflon end is placed in the stapedotomy, the wire hook is placed over the incus long process and crimped firmly. The mobility of the prosthesis is confirmed.
- 8.
Sealing footplate opening. The footplate opening around the piston is sealed with small pieces of fat taken from the skin wound to minimize perilymph leak.
- 9.
Most otosclerosis patients’ eardrum are intact, so it is unnecessary for them to require repair of the eardrum. Conversely, intact eardrum is seldom seen in tympanosclerosis, we prefer to restore the eardrum at a first stage operation and do stapes surgery at later time.
- 10.
Reposition the tympano-meatal flap and pack the canal with erythromycin soaked gelatin sponge or other absorbable material then pack the external auditory canal with iodoform gauze.
- 11.
Suture the incision using interrupted sutures and apply a sterile dressing
Special Comments
- 1.
Ensure good expose of the stapes.
- 2.
Protect facial nerve to avoid injury and facial paralysis.
- 3.
Sever the stapedius tendon close to the pyramidal eminence to ensure good exposure of the posterior crus.
- 4.
Dissection near the stapes footplate and its fenestration needs to be done with great care to avoid its mobilization or dislocation and consequent inner ear injury.
- 5.
Measure the distance from the incus to the stapes footplate exactly to assess the appropriate length of the piston.
- 6.
The footplate fenestration around the piston is sealed with fat to prevent perilymph leak. The fat should be placed carefully to prevent it entering the vestibule.
- 7.
If a gusher is encountered, the oval window should be sealed and the procedure terminated.
Complications
- 1.
Hemorrhage and infection. The operation is carried out under sterile conditions, with thorough hemostasis and using post-operative antibiotics.
- 2.
Deafness or severe hearing loss. Avoid injury to the membranous labyrinth.
- 3.
Facial paralysis. Facial nerve decompression is performed immediately if the facial nerve is injured during the operation or peripheral facial paralysis is present immediately after the procedure.
- 4.
Vertigo. Mild vertigo will occur in some patients after operation. This may be present for days but rarely more than 1 week. If it persists, re-operation should be considered, especially if it is accompanied by hearing loss and/or tinnitus.
- 5.
Perilymphorrhea. The fenestration around the piston should be re-sealed with fat.
- 6.
Taste disturbance is common and due to dissection of the chorda tympani nerve during surgery. This usually recovers within 1 month.
- 7.
Persistent middle ear blood clot or fluid. This usually resolves with time and gentle Eustachian tube inflation.
- 8.
If a tympanic membrane perforation occurs, it should be repaired immediately.
Fig. 4.20
Incision, dissection of tympano-meatal flap
A vertical incision is made anterior to the root of the helix and extended to the bony-cartilage junction of the external auditory canal. A circumferential incision is made under the microscope. It starts at the 6 o’clock point inferior, passes 4–5 mm from the annulus and extends superiorly to meet the first incision. The tympano-meatal flap is then elevated
Fig. 4.21
Exposure of tympanic cavity
Elevate the annulus from the tympanic sulcus superiorly and inferiorly. Reflect the tympano-meatal flap forward to expose the middle ear cavity. Curette the superior meatal spine if necessary. The lenticular process of the incus is identified and the blood vessels over the promontory are clearly seen
Fig. 4.22
Exposure of the stapes
Curette part of the postero-superior EAC wall to expose the long process of the incus. The chorda tympani and the horizontal part of facial nerve is seen
Fig. 4.23
Stapes superstructure removal
Protect the chorda tympani. Confirm the stapes fixation. Disconnect the incudostapedial joint. Sever the stapedius tendon close to the pyramidal eminence. Down fracture the anterior and posterior crura of the stapes. Remove the superstructure of the stapes
Fig. 4.24
Exposure of stapes footplate
The stapes footplate fixation is confirmed
Fig. 4.25
Fenestration of stapes footplate
The blue appearance of the oval window is apparent through the fenestration
Fig. 4.26
Fenestration of stapes footplate
Clear perilymph is seen through the footplate opening
Fig. 4.27
Implantation of stapes prosthesis
The Teflon end of the piston is trimmed to appropriate overall length (3.75–4.5 mm). The Teflon end is placed in the stapedotomy, the wire hook is placed over the incus long process and crimped firmly. The mobility of the prosthesis is confirmed
Fig. 4.28
Seal the oval window
The footplate opening around the piston is sealed with small pieces of fat from the skin wound to minimize perilymph leak
Endolymphatic Sac Decompression
Song Gao7 and Pu Dai7
(7)
Department of Otolaryngology, The 175th Hospital of PLA, Zhangzhou, 363000, China
Indications
This procedure is used in patients with Meniere’s disease where medical treatment has failed to relieve the frequency and severity of the vertigo.
Contraindications
- 1.
Acute infection in middle ear.
- 2.
Current Acute attacks of vertigo.
Operative Procedures
- 1.
A postauricular incision is made from the superior extremity of the auricle to the mastoid tip, about 10 mm posterior to the postauricular crease. Incise the skin, subcutaneous tissue, and periosteum of the mastoid to expose the entire mastoid cortex.
- 2.
Using a cutting bur, the mastoid cortex is removed from the cribriform area to expose the mastoid antrum which lies 10–15 mm deep to Macewen’s triangle.
- 3.
A complete mastoidectomy is performed and the lateral semicircular canal, posterior semicircular canal, sigmoid sinus, sinodural angle and facial nerve canal are exposed. The posterior fossa dural plate lies deep to the Trautmann triangle which lies between the mastoid tegmen, sigmoid sinus, posterior semicircular canal.
- 4.
After completion of the mastoidectomy, the endolymphatic sac is located in a thickened portion of posterior fossa dura medial to the sigmoid sinus and inferior to the posterior semicircular canal, that is inferior to the Donaldson line. This line is an imaginary line extending through the long axis of the lateral semicircular canal and bisects the posterior semicircular canal. Using a diamond bur, remove the bone covering the posterior fossa dura over an area of approximately 1 cm × 2 cm.
- 5.
Exposing the Sac. In the area of bone removal, separate the dura using a micro elevator, and expose the white sac and light blue dura.
- 6.
Incising the Sac. After identifying the Sac, cut its lateral surface with small sickle-shaped knife. A little fluid may be seen. In order to ensure smooth drainage, the incision should be large enough or a segment of the lateral wall of the sac can be elevated and rolled over or excised.
- 7.
The wound is thoroughly irrigated with saline and the mastoid cavity is filled with gelfoam. The wound is sutured in layers.
Special Comments
- 1.
A complete mastoidectomy is the first step of this surgery.
- 2.
Remove bone but leave an “eggshell” bone on the surface of the sigmoid sinus. The sinus is retracted posteriorly to assist with identification of the endolymphatic sac.
- 3.
Confirm the position of the lateral semicircular canal, and remove the cells between the facial nerve and posterior fossa dura.
- 4.
It may be difficult to find the endolymphatic sac if it is located inferior to the posterior canal. The wall of the endolymphatic sac is thicker and whiter than dura. Sometimes the sac is positioned close to the jugular bulb. In this situation the operator should be careful when cutting the sac.
- 5.
If the dura is lacerated by mistake, it is necessary to close it with sutures and muscle or fascia, in order to prevent a cerebrospinal fluid leak.
Complications
- 1.
Sensorineural hearing impairment. This is due to an inner ear injury which is more likely to happen in a sclerotic mastoid where it is difficult to distinguish the semicircular canal from surrounding bone. If such an injury occurs, suctioning over the open semicircular canal is avoided. Plug the fenestration with either muscle, fascia or bone paste or bone wax as soon as possible. Sensorineural hearing impairment is also likely to occur if the surgery fails to control the disease.
- 2.
Cerebrospinal fluid leak. This may occur when removing the bone over the posterior fossa and damaging the dura or incising the dura when trying to confirm the position of the sac. If this occurs, the injured dura should be closed directly or repaired with muscle or fascia.
- 3.
Facial paralysis. In some patients, the space between the sigmoid sinus and the descending portion of the facial nerve is small, and injury to facial nerve is more likely to happen when removing the air cells in this region. Facial function usually returns within several weeks in mild injuries; but, facial nerve transplantation or facial nerve- hypoglossal nerve anastomosis will be necessary in severe injuries.
Surgery1: Endolymphatic Sac Decompression
Fig. 4.29
Exposure of mastoid cortex
A postauricular incision is made from the superior extremity of the auricle to the mastoid tip, about 10 mm posterior to the postauricular crease. Incise the skin, subcutaneous tissue, and periosteum of the mastoid to expose the entire mastoid cortex
Fig. 4.30
Opening the mastoid antrum
The mastoid cortex is removed in a systematic fashion. The first cut is made along the temporalis line toward the sinodural angle. This line is the landmark of middle cranial fossa dura. A second cut perpendicular to the first is immediately posterior to the posterior external auditory canal wall toward the mastoid tip. The third cut connects the first two along the surface projection of the sigmoid sinus. Dissection parallel to a given landmark and removal of bone in layers is safe. Deep drilling at one single point must be avoided. Wide saucerization is necessary for adequate visualization of deeper structures
Fig. 4.31
Cavity saucerization
Cavity saucerization is completed. The posterior external canal wall should be thinned, and the mastoid tegmen exposed as is the mastoid tip. The area of bone removal posteriorly is larger than that of a normally saucerized mastoid cavity. The bone over the sigmoid sinus is thinned
Fig. 4.32
Exposure of lateral semicircular canal
Enlarge the aditus ad antrum to promote drainage and ventilation between the middle ear and mastoid cavity, and avoid blockage of the aditus with granulation tissue post-operatively. To avoid injury to the labyrinth, the area of exposure should not be deeper than the prominence of lateral semicircular canal
Fig. 4.33
Exposure of endolymphatic sac
The bone over the sigmoid sinus and posterior fossa dura is thinned and removed. The sigmoid sinus is retracted posteriorly. The bone between the sigmoid sinus and posterior semicircular canal removed. The posterior fossa dura is exposed and retracted posteriorly to identify the endolymphatic sac
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