Canal wall up Mastoidectomy ( Intact Bridge Mastoidectomy) by Dr.Aditya Tiwari

Canal wall up Mastoidectomy ( Intact Bridge Mastoidectomy) by Dr.Aditya Tiwari

1. “ Canal Wall Up Mastoidectomy ” By: Dr. Aditya Tiwari, Resident, Dept. of ENT. 16/09/2014

2. OUTLINE Introduction History Relation  Anatomy  Pathophysiology Etiology  Diagnosis Treatment  Defination . Indication & contraindications Pre op. evaluation & counseling Techniques Complications References.

3. INTRODUCTION Desciption of chronic and suppurative infections of the mastoid have been discovered dating back to ancient Greece. Mastoid surgery has evolved from simple trephination for acute infections, to the canal wall preserving mastoidectomy. The complete (or simple) mastoid operation, refers to canal-wall-up (CWU) mastoidectomy, with complete removal of diseases from temporal bone lateral to otic capsule. It is usually accompanied by tympanoplasty & ossicular chain reconstruction.

4. HISTORY Mastoid operation have been employed for over 300 years to control suppurative diseases of the ear, but first proposed mastoidectomy date back more than four centuries. Ambrose Pare proposed to operate on skull & drain pus. Jean Petit of Paris reported the first successful mastoid trephination operation in late 1700s. The first postauricular incision was introduced in 1853 by Sir Willian Wilde of Dublin. Schwartze & Eyeshell reported the use of cortical mastoidectomy for management of acute mastoid infections.

5. Zaufal , in 1890, described the radical mastoidectomy with the additional removal of the TM, ossicles & post. w all of EAC. Bondy described opening the epitympanum and leaving the middle ear intact. In 1902, Sir Charles Balance was the first to advocate the complete mastoid operation for control of advanced suppuration of the ear. Lempart popularised the use of a drill & loupe magnification in the 1928. With the introduction of Zeiss operating otologic microscope in 1923 & description of CWU mastoidectomy by JANSEN, the paradism for mastoid surgery changed dramatically for acute & chronic mastoid infections. 1958 , the canal wall up mastoid was then popularized by House. He also introduced the suction irrigation system and retractors in mastoid surgery .

6. RELATION OF THE MASTOID ANTRUM There are four parts to the temporal bone: petrous, tympanic, mastoid, and squamous A transmastoid procedure allows access to the facial nerve, internal carotid, jugular, and internal auditory canal

7. ANATOMY- AXIAL MASTOID VII- seventh cranial nerve; VIII- eighth cranial nerve; APA- anterior petrous apex; Ca- carotid artery; CT- chorda tympani; EAC- external auditory canal; ET- Eustachian tube; Fn - facial nerve; IAC- internal auditory canal; KS- Körner septum; LSC- lateral semicircular canal; PPA- posterior petrous apex; PSC- posterior semicircular canal

8. PATHOPHYSIOLOGY Primary role of CWU mastiodectomy is in the control of chronic otitis media, with and without cholesteatoma & acute mastoiditis . It is also used as a standard approach for cochlear implantation, excision of tumors & surgery for vertigo. Incision & drainage of subperiosteal abscess,& placement of tympanostomy tubes & antibiotics, without mastoidectomy, suffice in the treatment of most of cases of acute mastoiditis .

9. Acute mastoiditis arises from untreated acute otitis media, otitis media that fails to respond to antibiotics. Coalescent mastoiditis is acute mastoiditis in which a localised collection of pus has accumulated in the mastoid, with evidence of erosion of the normal bony septae within the mastoid cavity. Persistant purulent otorrhea for more than 3 weeks after AOM, pain behind the ear, or pain deep in the ear are indications that coalescence may be developing. Many signs & symptoms seen in both AOM & coalescent mastoiditis , but their persistance 2-3 weeks after the onset of infection is more s/o coalescent mastoiditis .

10. It can present as a postauricular subperiosteal abscess & definatively diagnosed by CT scan. Subacute mastoiditis – slow, silent progression of a coalescent abscess, is a potentially dangerous consequence of partially treated AOM. It evolves over several weeks. CSOM defined as chronic inflammation of the middle ear & mastoid, can be seen with or without cholesteatoma . Most commanly it manifests as hearing loss & intermittant otorrhea . Usually painless but acute condition is painful. Vertigo is uncomman but if present concerns for labyrinthine fistula or inflammatio n .

11. Pathologic findings of CSOM includes osteitis (most often seen in ossicle , otic capsule & mastoid bone) , mucosal edema with submucosal gland formation, granulation tissue, tympanosclerosis , cholesterol granulomas, cholesteatoma , & TM retraction and perforation. Bone erosion from osteitis can result in ossicular discontinuity, dural exposure with or without brain herniation, meningitis & labyrinthine fistula. Granulation tissue most commanly seen in e pitympanum & round window niche, blocking the aditus  preventing aeration of the mastoid & subsequent resolution of infection.

12. ETIOLOGY OF CSOM CSOM is believed to caused by ETD  persistant middle ear discharge (serous/purulent) mucosal edema formation of granulation tissue. Bacterial infection via chemical mediators Granulation tissue formation initiated in inflamed mucosa bacterial toxin + inflammatory mediators acts on edematous mucosa rupture of the BM of epithelia Inflammatory cells in underlying lamina propria  extrude through BM secrets AGF, EGF leads to fibroblast recruitment, neovascularisation & polyp formation.

13. TM affected by the enzymes contained in the granulation tissue & chronic effusion  breaks down its collagen skeleton. The weakening of TM & negetive pressure in the middle ear from ETD develops retraction pocket in the TM. Deepening of the retraction pockets leads to contact with the underlying mucosa or granulation tissue & fibrous band cause perforation. Deep retraction pockets & perforation set the stage for the genesis of cholesteatoma .

14. DIAGNOSIS ACUTE MASTOIDITIS:- Begins as AOM  Deep thrombing ear pain with asso . with pus in the middle ear purulent otorrhoea . TM erythematous & bulges laterally Fever, leukocytosis , tender mastoid, tender post auricular skin COALESCENT MASTOIDITIS:- AOM persisting over days or weeks after infection Disproportionate deep pain, mastoid tenderness, erythema or swelling.

15. CSOM:- Foul smelling intermittant otorrhoea , hearing loss, otalgia , headache. Conductive hearing loss is comman . Its greater than 30dB suggest ossicular erosion. SNHL ranging from 5 to 33 Db. EAC should be noated for edema, cholesteatoma . TM should be noated for perforation, retraction, atelectasis, or cholesteatoma . Look for scutum erosion, ossicular erosion, granulation tissue, vertigo(raising suspicion of labyrinthitis or fistulas)

16. PAEDIATRIC CHOLESTEATOMA Cholesteatoma is more aggressive in paediatric patients due to the following reasons:- Immature eustachian tube  facilitate TM retraction & cholesteatoma Increased amount of growth factor in children  faster growth rates in cholesteatoma Increased & better aeration in paediatric patients  facilitate spread of cholesteatoma through middle ear & mastoid  complicate disease removal Faster replication rate of keratinocytes in paediatric cholesteatoma Vs adults.

17. TREATMENT MEDICAL TREATMENT Broad spectrum antibiotics – oral or i.v . Ototopical antibiotics. Insertion of tympanostomy tube. Analgelsics . Antihistaminics . Antacids – oral or i.v .

18. SURGICAL THEORY & PRACTICES Simple Mastoidectomy Closed or Canal Wall Up Mastoidectomy Cortical mastoidectomy Combined approach tympanoplasty Tympanoplasty with mastoidectomy Open or Canal Wall Down Mastoidectomy Atticotomy Radical mastoidectomy Modified radical mastoidectomy

19. Modifications of intact canal wall Mastoidectomy: 1) Atticotomy with preservation of the intact bony bridge 2) Atticotomy with preservation of a partly resorbed bony bridge 3) Atticotomy with removal of the bridge 4) Widening of the ear canal Atticotomy openings of various sizes with preservation of the intact non resorbed bony bridge The goal of this atticotomy is to obtain a good view into the anterior attic. The bridge remains in its normal position

20. DEFINITIONS Cortical mastoidectomy :- This is an operation performed to remove the mastoid antrum & air cell system and aditus & antrum, with preservation of intact post. b ony EAC wall without disturbing the existing middle ear content. Combined approach tympanoplasty :- This is an operation performed to remove disease from the middle ear & mastoid by the way of the m astoid a p osterior tympanotomy , & t he t ranscanal r oute, followed b y t he r econstruction Of the middle ear transformation mechanism

21. SCOTT BROWN DIAGRAME

22. Tympanoplasty with mastoidectomy :- This is an operation performed to eradicate disease from the middle ear and mastoid & to reconstruct the hearing mechanism with or without tympanic membrane grafting. e.g. Combined approach tympanoplasty or cortical mastoidectomy with tympanoplasty Obliteration technique – muscle or other obliteration of an open mastoid cavity with tympanoplasty Canal wall reconstruction technique – reconstruction of the outer attic post. Canal wall of an open mastoid cavity, with tympanoplasty Open cavity technique – open or canal wall down mastoidectomy with tympanoplasty

23. ATTICOTOMY - remove all part of outer attic wall( scutum ) and adjacent deeper post meatal wall to expose the attic ( epitympanum ) and when necessary the aditus and antrum to gain acess to these sites and their content and / or to remove disease limited to this site RADICAL MASTOIDECTOMY- to eradicate all middle ear and mastoid disease , in which mastoid antrum and air cell system ( when present) , aditus and antrum, attic and middle ear( mesotympanum and hypotympanum ) are converted in to a common cavity exteriorzed to the external auditory meatus. During this procedure TM, incus, malleus all removed except stapes ( foot plate alone or with stapes supra structure if healthy. RM- TM or reminant thereof and ossicular remenants ( usually the malleus handle and stapes) are retained

24. INDICATIONS 3 priorities in surgery for CSOM are :- eradication of disease prevention of disease recurrence preservation or restoration of hearing Mastoidectomy in CSOM has 3 primary indications :- eradication of disease & infection approach for removal of cholesteatoma establishing aeration previous tympanoplasty failure & perforated TM with persistant suppurative drainage.

25. CONTRAINDICATIONS TO CWU MASTODECTOMY Unresectable posterior canal wall defect Patient in which proper follow up is questionable Unresectable matrix involving the labyrinth, facial nerve, carotid, dura, sinus tympani. Only hearing ear Patients with labyrinthine fistula Long-standing ear disease Poor eustachian tube function Active infection & otorrhoea are not c/i to surgery, but ear should be made dry pre op. since the rate of post op infection is higher when an ear is operated while draining.

26. PREOPERATIVE EVALUATION Preoperative audiometry. IMPEDENCE X RAY mastoid HRCT scan of the Temporal bone. ( pneumatization , and position of the tegmen and the sigmoid sinus and extend of the disease) EUM

27. PRE-OP COUNSELING - RISKS OF SURGERY Facial paralysis Vertigo Tinnitus Hearing loss Staged procedure Need for long term follow-up and routine aural toilet

28. OPERATIVE TECHNIQUE FOR CWU MASTODECTOMY PREPARATION Pre operative antibiotic or steriods Supine position with head turned away from affected ear Hair may be shaven if it is in the operating field, or taped to keep it out of the field. Injection with lignocaine with epinephrine ( postaurally and canal skin in sup. , post, inf ) Antibiotics ( ciprofloxacin 400 mg iv or betadine soln mixed with saline) for irrigation

29. APPROACHES: (SOFT TISSUES) Endaural Retroaural Vasular strip incisions

30. Retroauaral approach Endaural approach Attic is oblique in postero anterior direction, distance to attic is longer. Mastoidectomy is easy to be extended Cavity obliteration by flaps is possible Both trans meatal and transcortical routes can be taken Cavities produce is larger Attic view is direct latero medially and distance to attic is shorter Difficult to extend Cavity obliteration not possible Posterior tympanum and sinus tympani is better viewed Only transmeatal route is route of choice Cavities produce is smaller

31. ROUTES: (BONE) Transcortical starts over cortex of mastoid process also described as outside in Transmeatal starts in the bone of ear canal also described as inside out atticotomy  antrostomy  retrograde mastoidectomy

32. SIMPLE MASTOIDECTOMY Indication – acute mastoiditis , commonly called “ coalescent mastoid ” Medical management failure of chronic suppurative otitis media/ mastoiditis As an approach to: Facial nerve decompression Endolymphatic sac decompression Labyrinthectomy

33. A post-auricular 1cm post. to sulcus approach is used . Young children the mastoid tip is not well developed and the stylomastoid foramen is located more superficially, making the facial nerve vulnerable to surgical trauma. The inferior aspect of the incision is more posterior and is not carried down as far to avoid injuring the facial nerve .

34. Carry the incision to the loose areolar tissue over the temporalis facia.. CORTICAL MASTOIDECTOMY The cortex is exposed by an incision through the linea temporalis, with a vertical cut extended to the posterior mastoid tip, in a T fashion. An elevator is then used to free the cortex off the soft tissue. C shaped incision provides better exposure in a previously drilled cavity, prevent injury to the important underlying structure such as sigmoid sinus & middle cranial fossa .

35. Cortex exposed Sup. - over the tegmen Post. - over sigmoid sinus Ant. - level of EAC meatus Inf. – mastoid tip Self retaining retractors are positioned and the surface landmarks are identified,which include the spine of Henle , cribriform area , & linea temporalis.

36. MacEwen’s triangle shows the location of the antrum. MacEwen’s triangle is defined as the posterior EAC border, the anterior line of the zygomatic arch and the line that connects the two. The antrum is 15 mm medial the this. Removing bone along the linea temporalis Identify underlying tegmen ( pink hue) Middle cranial fossa dura delineated to its superior extend.

37. CANALPLASTY Using 2mm diamond burr, excess tympanic bone at the tympanomastoid & tympanosquamous suture line is removed. If required, the entire EAC can be enlarged, from 12 o’clock to 6 o’clock position posteriorly. The distance of facial nerve from the annulus in the posterior-inferior quadrant of the EAC ranges from 1.9mm to 5.7mm  facial nerve is at most risk to injury during surgery. Often removal of this small amount of bone greatly improves the exposure, ensuring better disease resection & graft placement.

38. Completed canalplasty with entire annulus visible

39. Various drills are available and there are common principles related to bur selection Larger bur preferred over smaller ones when possible A bur with a cutting surface is selected for cortical bone, were diamond grain surface is for removing the last layer of bone over facial nerve, sigmoid sinus, tegmen , & opening the facial recess. Suction irrigation is critical to prevent excessive heat transfer to underlying structures & to keep the bone cool. Diamond burrs are effective at controlling bleeding in the bone by driving bone dust into the lumen of the small vessels Also , it is important to “ saucerize ” the edges of the mastoid cavity to provide visualization.

40. Cortical bone removed post to EAC (post- sigmoid sinus bluish hue and sinodural angle , inf - mastoid tip). Cortical bone is removed inferiorly to the mastoid tip Surface of the tegmen followed medially towards the antrum and the air cells are exposed. KOERNER SEPTUM penetrated ANTRUM

41. Dural plate and lateral semicircular canal Postero -anterior view through antrotomy and aditus ad antrum into epitympanum Dural plate LSSC BODY OF INCUS SHORT PROCESS FACIAL NERVE DURAL PLATE LSSC

42. Sigmoid sinus, sinodural angle and dural plate Correct length of a cutting burr in the drill A diamond burr can be lengthened in order to safely drill deeper in the mastoid DURAL PLATE SINODURAL ANGLE SIGMOID SINUS

43. SIMPLE (DISEASED) CANAL WALL UP MASTOIDECTOMY This is an extension of the simple mastoidectomy with greater access to the attic, labyrinth, endolyphatic sac, antrum and facial nerve. Opening of the aditus ad antrum allows access to the epitympanum , and the incus and malleus may be removed for greater access The canal wall remains up .

44. INDICATIONS Treatment of Cholesteatoma & suppurative mastoiditis Exposure of mastoid segment of facial nerve. Cochlear implant, in which a posterior tympanotomy is part of the procedure L abyrinthectomy and mastoid trauma Retrolabyrinthine approachs to the vestibular nerves Exposere of the sigmoid sinus for obliteration before petrosectomy

45. Exposure of the mastoid region in CAT, to delineate the descending portion of the facial nerve & to provide the access for opening the posterior tympanotomy into the middle ear. Saccus decompression surgery, to offer the safest & widest access to the posterior fossa dura. Translabyrinthine operations, to provide the exposure of the bony labyrinth needed for its exenteration to allow access to the IAM.

46. ATTIC DISSECTION  P OST. EPITYMPANOTOMY P erformed by following the tegmen anteriorly & by thining the canal wall posteriorly & superiorly. C anal wall thinned laterally to medially. Drilling out of zygometic root  opening of the attic Granulation & cholesteatoma removed. Attic cell are opened completely & fully exposed in any epitympanic disease. Ant. attic is most comman site of residual disease. As the epitympanum approached from the post to ant,the tegmen is carefully followed as it usually dips inferiorly.

47. After the Dissection , the anterior epitympanum , zygomatic cells, body of incus and head of malleus are identified. Cultures can then be taken from the mastoid mucosa, if needed.

48. FACIAL NERVE:- IDENTIFICATION is most important to avoid injury Travels as GG  sup to cochleariform process & oval window. P ost to oval window takes inf. turn to take on a more vertical course. LSC lies just sup to facial nerve as it complete it transition to the vertical segment.

49. SECOND GENU is located a few mm anteromedial to the lat. SSC & is ANATOMICAL LANDMARK for localizing the facial nerve. Diagrastric ridge another land mark Burr stroke should be the parallel to the course of the nerve Its gently uncovered until it is observed through a thin layer of bone. If the disease is limited to the antrum, uncovering the vertical segment of the facial nerve is rarely done.

50. Relations of VIIn to short process of incus; superior semicircular canal (SCC); lateral semicircular canal (LSC); posterior semicircular canal (PSC); dura; and sigmoid sinus DURA SSC SIGMOID SINUS FACIAL NERVE INCUS LSC

51. Distal portion of mastoid segment of facial nerve (arrow) is identified close to digastric ridge

52. FACIAL RECESS (POST. TYMPANOTOMY) Not required in all CWU mastoidectomy, e mployed only when dictated by the location of the disease. Thin the posterior canal wall Boundaries :- a) Superior : Incus or incus buttress b) Posterior : Facial nerve c) Anterior : Bony EAC , chordae tympani d) Inferior : Bifircation of facial nerve & chordae tympani

53. Boundaries of the Facial recess

54. Access to the mesotympanum can be gained by removing the bone in the facial recess after thinning the post. canal wall. For additional exposure, the facial recess can be extended inf. by sacrificing the chorda tympani nerve. Entire mesotympanum & hypotympanum can usually be accessed through the mastoid by the extended facial recess approach.

55. C horda tympani nerve is identified as it branches off the vertical segment of the facial nerve & traced sup. Toward the incus. Facial recess is opened with a 2 mm diamond burr, starting sup. w here it is widest. EXTENDED FACIAL RECESS approach involve sharply sectioning the chorda tympani nerve & extending the recess ear inferior along the facial nerve course. The lateral boundary of the exposure becomes the annulus of the tympanic membrane.

56. Landmarks for posterior tympanotomy A) VIIn , B) chorda tympani & C) short process of incus A B C

57. FACIAL RECESS A = antrum, C = chorda tympani, F = facial nerve, HSC = horizontal semicircular canal, I = incus, R = round window, S = stapes

58. EPITYMPANOTOMY If the cholesteatoma does not extend significantly into the epitympanum , an epitympanotomy ( atticotomy ) is performed This involves exposure of the head of the malleus and the incus to remove soft tissue from the epitympanum . The lateral wall of the epitympanum or attic is removed with a diamond burr; drilling is commenced at 12 o’clock relative to EAC, taking care not to make drill contact with the malleus or incus which is immediately medial to the outer attic wall, or to breach the dural plate above

59. Direction of drilling with epitympanotomy or epitympanectomy

60. EPITYMPANECTOMY This is indicated when cholesteatoma extends medial to the ossicles or overlies the lateral semicircular canal; in cases of bony erosion of the ossicles due to cholesteatoma , the ossicles need to be removed The incus is removed by mobilising it with a 2,5mm. 45° hook and rotating it laterally, taking care not to injure the underlying facial nerve . The malleus head is severed with a malleus nipper applied across its neck.

61. The head of the malleus is removed leaving the tensor tympani tendon intact. Clear cholesteatoma from the epitympanum . Detailed knowledge of facial nerve anatomy is crucial to avoid injury to the nerve when drilling or removing cholesteatoma in the epitympanum . The tympanic and labyrinthine segments and geniculum all lie in this very confined space and may be dehiscent. The tympanic segment lies in the floor of the anterior epitympanic recess.

62. Anatomy of anterior epitympanic recess: Facial nerve ( VIIn ); Tegmen tympani (TT); Cog; Supratubal recess StR ; Cochleariform process (CP); Eustachian tube ( ET TT VIIn Cog StR CP TTymp ET

63. The cochleariform process is a fairly consistent landmark and the nerve lies directly superior to it; the semicanal of the tensor tympani is sometimes mistaken for the facial nerve; however this canal ends at the cochleariform process. The Cog is a bony process in the anterior epitympanum which extends from the tegmen tympani and points to the facial nerve. Geniculate ganglion and GSPN seen once the Cog and cochleariform process have been drilled away (as shown follow )

64. View of epitympanum with cog and cochleariform process drilled away: Tympanic (VII.T) and Labyrinthine (VII.L) segments of facial nerve and Geniculate Ganglion (GG) and Greater Superficial Petrosal nerve (GSP); Superior Semicircular Canal (SSC); Lateral Semicircular Canal (LSC); Dura; Tensor Tympani tendon (cut) ( TeT )

65. Completed closed mastoidoepitympanectomy

66. FISTULA OF LSC A small dimple or flatttening in the matrix covering the bone over LSC may believe as a fistula LARGE SMALL Greater then 2 mm diameter Smaller then 2 mm diameter Convert it in to a canal wall down procedure Second look procedure 12 month later or repair it by fascia or perichondrium

67. Combined Approach Tympanoplasty ( i.e. “Canal Wall Up”, “Intact Canal Wall”, “Closed-cavity tympanomastoidectomy ”) Prevent tympanomastoid cavity  considered in diploic or pneumatic air cell systen with disease Primary objective is removal of the disease, not the preservation of post EAC wall. Posterior EAC wall drilled to widen Korner’s septum drilled & antrum is exposed Saucerization of the outer cortex not so imp as in complete mastoidectomy

68. Aditus enlarged to readily visualise incus  epitympanum inspected through the aditus & antrum. The facial recess & sinus tympani are exposed & cleared of disease tympanoplasty is accomplished. A silicone rubber sheet may be placed, extending from the middle ear into the antrum ensures the free flow of air between the middle ear & mastoid cavity.

69. Removing cortex over antrum Antrotomy done Korner’s septum encounteredremoved to expose antrum

70. Incus identified & aditus enlarged to expose attic Critical oval window area & recess visualised through a) canal & b)mastoid Complete mastoidectomy

71. Open Cavity Mastoidectomy Excision of the conchal cartilage via endaural or postaural approach  Korner flap or endaural incision to creat a flap can be constructed connect them with post. i ncision parallel to tympanic annulus. The endaural incision extended from the post. annulus incision in EAC to conchal bow large crescent shaped piece of conchal cartilage removed without injuring canal skin & retaining continuity with the Korner flap.

72. To provide an opening adequate to allow drainage & surgical defect, meatoplasty should comfirtably accept the surgeon’s finger. To prevent post op. stenosis by granulation tissue formation  curettage, steroid antibiotic ointment, Thiersch grafting using very thin split thickness skin (3 weeks after surgery). If stenosis occurs, it will be necessary to elevate & preserve meatal skin & to drill or curette the bone widely to creat a large meatus.

73. Completed mastoidectomy with tympanoplasty a) Conchal cartilage is excised to create a large meatus. & b) Korner flap is developed

74. The graft is placed in position(a). & the musculofacial pedicle is placed into the finished mastoid cavity(b).If it is large, post. Wound will be sutured & drained & the Korner flap placed on top of the muscle through an endaural exposure.

75. ADVANTAGES OF CWU MASTOIDECTOMY Rapid healing time Easier long-term care Hearing aids easier to fit No water precautions

76. DISADVANTAGES OF CWU Technically more difficult Staged operation often necessary Higher chances of recurrent or residual disease Residual disease harder to detect Children with cholesteatoma 2 nd look is required to rule out recurrence or residual disease. Periodical & meticulous follow up needed.

77. COMPLICATION It occurs as a result of :– Inadequete surgical exposure Failure to recognize the anatomical variation. Granulation or bleeding obscuring the surgical field. They are as follows-

78. Bleeding  due to injury to the jugular bulb and dural plate or sigmoid sinus SNHL  high frequences losses Vertigo Infection Granulation tissue Brain herniation CSF leak

79. Intracranial injury:- Exposure of dura with spinal fluid leak Small herniation of brain (less than 5mm ) managed with gentle bipolar cautery. Large herniation of brain (more than 5mm) managed with middle fossa craniotomy approach, with the assistance of nerurosurgeon

80. Facial nerve injury:- a) Mastoidectomy is the most comman cause of iatrogenic facial nerve palsy . b) When graeter than 50% of nerve is transected , managed by resecting the injured segment & grafting the nerve. c) In case of subtotal transection of the facial nerve, it is proximally & distally decompressed and injury is assessed. 8) Suppurative labyrinthitis . 9) Postauricular haematomas ( if the patient coughs or strains during the postoperative period)

81. REFERENCES Bailey BJ, et al, eds. Head and Neck Surgery - Otolaryngology. 4nd ed. Philadelphia Pa: Lippincott-Raven; 2006 Antonelli PJ, Dhanani N, Giannoni CM, et al. Impact of resistant pneumococcus on rates of acute mastoiditis .  Otolaryngol Head Neck Surg. Sep 1999;121(3):190-4 Shambaugh GE, Glasscock ME. Canal wall up mastidectomy . Surgery of the Ear.  Shambaugh  GE,  Glasscock  ME : open cavity mastoid operation Surgery of the Ear.   Scott brown 6th edition anatomy of the middle ear Bluestone CD. Acute and chronic mastoiditis and chronic suppurative otitis media. In: Feigin RD, editor, Wald ER, Dashefsky B, guest editors. Seminars in pediatric infectious diseases. Vol 9. Philadelphia: WB Saunders; 1998;9:12–26.