15Abnormal morphology of the LSO and LMR compared with normal Rt side.
16No intervening fat between LMR and orbital wall, nor between L SO and MR (compared to the Rt).
17The MR tethered at midpoint to the lamina papyracea.
18PlanOptions: 1. To try to free up the muscle from where it is stuck to the bone (has an appointment with orbital doctor). 2. Do a Muscle Sx w/o correcting the orbital wall/ freeing the Muscles.
19Option 2 a. Surgery LIO weakening procedure. LMR resection If LLR tight LLR recession.* Since this will make her ET in LG , she needs yoke muscle RMR recession (adjustable).b. BOTOX to the LLR/LIO (less reliable results than Sx).
20Literature 1A retrospective review of four cases of severe orbital trauma during endoscopic sinus surgery.All the cases suffered MR damage,One had additional injury to the IR and IO, andTwo patients were blinded due to direct damage to the optic nerve or its blood supply.C Rene, G E Rose, R Lenthall, I Moseley. Major orbital complications of endoscopic sinus surgery. Br J Ophthalmol 2001;85:598–603)
21Literature 1: CASE 2 A 52 year old man. underwent right transnasal endoscopic ethmoidectomy for polyposisC/O : post op diplopiaO/E :Large SCH, No proptosis.VA 6/4 R + LNo RAPDIshihara – normal R+LRXT, normal aBduction, no aDduction across the midlinePt had orbital wall repair
22A-C: 11 d post-op: RXT, good right aBduction but no aDduction of the Re, marked HypoT on attempt LG Case 2D-H: 9/12 post-op: X(T), improved alignment in PP and LG16/12 after orbital repair, pt had LLR rec for X(T).
23Case 2Axial CT: a defect in the right lamina papyracea to which the RMR is adherent (arrow);The eye in abduction.There is extensive sinus diseaseCoronal sections: The RMR is displaced medially (arrow) into the defect in the right nasal cavity. The muscle is visible just in front of the defect and cannot be seen in its posterior end.
24MR injuryThe MR is adjacent to the lamina papyracea and was injured in all (4/4) pt’s due to direct loss of muscle/entrapment.The injury is associated with divergent strabismus, with almost absent of aDduction.Also likely a damage to the nerve/vascular supply to the muscle - in which case a slow recovery of aDduction is anticipated.
25ON injury2/4 pt’s suffered blindness due to direct optic nerve damage.The intraorbital ON can be damaged by instruments entering the orbit/ by distraction of tissues from the orbit into the ethmoidectomy site.
26Predisposed factors for inadvertent orbital entry during ethmoid sinus Sx. Nasal approach (rather than extraorbital );A very thin/incomplete lamina papyracea;Anatomical variants in the sinus/when using sinus debridement;Disruption of normal anatomy from disease or previous Sx.
27Awareness that this can be a complication hence, Assess pre-op with a CT scan: info about the extent of the sinus disease, anatomical variants and lamina papyracea location.Periodically uncover the eyes during Sx. Monitor: sudden swelling/ bruising, proptosis, eyeball movements (d/t traction on orbital fat), dilated/ poorly reactive pupil and RAPD, tense proptotic orbit and compressive optic neuropathy d/t orbital hemorrhage.
28Ophthalmic treatmentA Hx of Dip post sinus surgery and a motility defect is strongly suggestive of orbital entry during sx.If enophthalmos or muscle entrapment plan orbital exploration and release of entrapped tissues strabismus surgery.If no MR entrapment consider inducing paralysis of the Ipsi lateral antagonist with BTX to minimize contracture while awaiting recovery of the orbital soft tissue injury. Later, repair of the large angle XT or X(T).Should the MR be essentially absent, then medial transposition of the vertical recti may be required with botulinum toxin paralysis of the LR.
2930 cases from 1994 to 2000 gathered from 10 centers. Literature 230 cases from 1994 to 2000 gathered from 10 centers.16 men and 14 women.Mean age: 45 years (range, years).Follow-up from initial injury: 12m (2- 48m).A spectrum of MR injury: simple contusion to complete MR transection, w and w/o entrapment.Christine M. Huang, et al. Medial Rectus Muscle Injuries Associated With Functional Endoscopic Sinus Surgery (Ophthalmic Plastic and Reconstructive Surgery), 2002
30Four general patterns of presentation and corresponding injuries were categorized: Our pt is pattern IITx in group I and II (MR tissue loss), were challenging.Observation / IV steroids alone did not result in improved ocular alignment.Early exploration of the entrapped muscle with suturing the muscle remnants, BTX injection to the ipsilateral antagonist (LR), improved primary ocular alignment.Late orbital exploration had limited results.Vertical rectus muscle transposition as a secondary late procedure variable improvement on ocular motility.
31Discussion(1)The incidence of ocular complications during sinus Sx is low, but when they occur- have significant morbidity.With increasing interest in endoscopic sinus surgery, more ocular complications are likely to occur.MR, the most commonly injured extraocular muscle (direct laceration, neurovascular interruption, entrapment or adhesions to adjacent structures).Post-op CT is important in assessing the medial wall, the MR and surrounding orbital soft tissues and the size and location of the medial wall bony defect.
32Discussion (2) Treatment of the MR injury includes: Early exploration (within 2- 3/52), freeing or repair of entrapped tissues, and cover the bony defect with an implant if necessary.Reattachment of the lacerated ends of the MR improves PP alignment.Adjunctive weakening of the antagonist LR with BTX injection (5 units under direct visualization).Vertical transposition if MR transected, to improve aDduction.