Summary for the Clinician

■ Patients with active moderate-to-severe GO or active mild GO with su cient impairment on daily life should receive anti-inflammatory treatment.

■Glucocorticoids are applied most e ciently i.v. 250 mg–1 g weekly over 6–12 weeks or at consecutive days within 1 week (cumulative dose: 1.5–3g) followed by an oral regime (response rate about 80%). Cumulative doses of 8 g should not be exceeded to prevent liver damage and other severe side e ects.

■Orbital radiotherapy is indicated primarily for patients with impaired motility. Fractionated doses between 10 and 20 Gy are applied to each orbit (response rate about 60%).

■Combined therapy (glucocorticoids and orbital radiotherapy) is more e cient than each therapy alone.

■Patients with dysthyroid optic neuropathy should be treated with i.v. steroids as first-line treatment; if the response is poor after 1–2 weeks, they should be referred for immediate surgical decompression. In case of marked proptosis or severe corneal exposure, surgical decompression can be immediately performed.

■New therapeutic strategies for patients with severe GO are being tested – most promising is B cell depletion, which inactivates GO and supports remission of thyroid dysfunction.

■Simple measures like topical lubricants, botulinum toxin for retracted lids and prisms for compensation of double vision are important for the quality of life of the patients.

16.3.2Inactive Disease Stages

Rehabilitative surgery includes one or more of the following procedures: (a) orbital decompression, the usual indication for surgery being disfiguring exophthalmos with or without keratopathy; (b) squint correction; (c) lid lengthening; and (d) blepharoplasty/browplasty. Prerequisite for successful surgery is a minimum of 6 months of stable inactive ophthalmologic and thyroid disease. Concerning thyroid disease, this means either constant doses of Levothyroxin after definitive therapy (thyroidectomy/ radioiodine therapy) or stable remission at least 6 months

after cessation of antithyroid drug therapy. Because of its influence on ocular motility and lid width, decompression surgery should be performed first. Vertical squint correction may then be performed. Pseudoretraction will resolve postoperatively but lower lid retraction can occur after inferior rectus recession. Small medial rectus recessions can be combined with lid surgery; larger recessions should be performed separately [35, 36].

16.3.2.1Orbital Decompression

A wide range of surgical approaches is used to reduce disfiguring proptosis in patients with GO. The amount of proptosis reduction depends on the number of walls removed and whether or not fatty tissue is removed. Serious complications are rare. Common surgical approaches for orbital decompression are: coronal, via the upper skin crease, the lateral canthus, or the inferior fornix (both together = swinging eyelid), sub-ciliary, directly through the lower lid, transcaruncular, transnasal, and transanthral. Further restriction of ocular motility is still a major complication; this mainly occurs with medial wall decompression. The risk is much lower with removal of the lateral wall alone. Clinically obvious impairment of motility increases the risk of postoperative diplopia significantly.

At present, the medial, inferior, and lateral walls are addressed during bony orbital decompression (Fig. 16.3), while the orbital roof is neglected due to potential complications. Minimally invasive approaches and hidden incisions are preferred. Decompression of the medial orbital wall is necessary to decompress the optic nerve in patients with DON.

The transnasal endoscopic procedure addresses the medial and inferior orbital walls. The advantage of a convenient scarless procedure is opposed by the relative high risk of decreased ocular motility and inferior and nasal dislocation of the globe. Proptosis may be reduced by 2–5 mm.

With the coronary approach, all orbital walls can be accessed and proptosis reduction up to 10 mm can be achieved. This is, however, an elaborate procedure.

To enhance the e ect of lateral wall decompression, the procedure can be combined with removal of its deep portion or with additional fat removal (Fig. 16.3). The lateral wall has, due to a very low risk of diplopia, increasingly become the first choice for orbital decompression (traditional concept – inferior-medial decompression first) in cases of rehabilitative surgery. The approach to the lateral wall is variable via the upper skin crease,

swinging eyelid, sub-ciliary, or directly through the lower lid. Average proptosis reduction ranges between 2 and 5 mm. (Literature is reviewed in [37].)

16.3.2.2Extraocular Muscle Surgery

The basic concept for eye muscle surgery in GO is recession of the fibrotic muscle. The approach is di erent for inferior and medial rectus muscles. Vertical deviation increases with side di erences in monocular upward excursions. Bilateral symmetric restrictions of inferior rectus muscles cancel each other out and cases with abnormal head posture need to be corrected by symmetric inferior rectus recession. Bilateral restriction of abduction adds up. Di erent concepts for surgical strabism correction are available: preoperatively determined recession distances according to dose e ect curves, and intraoperative determination of recession distance via active or passive motility and adjustable sutures (literature is reviewed in [38]).

Principles for extraocular muscle surgery in patients with GO:

■Vertical squint – no head tilt when covering the eye with more limited upgaze: Recession of inferior rectus muscle: dose: 1 mm recession per 2° of intended squint angle reduction, maximal recession distance 7–8 mm, persisting vertical squint: second step: recession of the contralateral superior rectus muscle dose 1 mm/per 2° of intended squint angle reduction

■Vertical squint – head tilt when covering the eye with more limited upgaze: asymmetric bilateral inferior rectus recession (side di erence in mm depends on the squint angle, measured with head tilt: 1 mm recession per 2° of intended squint angle reduction)

■Horizontal squint <10°: unilateral medial rectus recession (side: eye with least abduction), dose 1 mm recession per 1.75° of intended squint angle reduction, maximal recession distance 6–7 mm

■Horizontal squint ≥10°: bilateral medial rectus recession, dose 1 mm recession per 1.6° of intended squint angle reduction (dose side di erent, when side di erence in monocular abduction), maximal recession distance per eye 6–7 mm

■Combined horizontal and vertical squint: small vertical angles disappear after correction of horizontal squint; a two-step procedure (large angle first) is more precise; if all in one procedure is preferred (only recommended for unilateral procedures): consider higher dose e ect for vertical squint 2.1° per mm recession

■Lower lid retraction after inferior recession can be prevented through dissection of the capsulopalpebral ligament. Upper lid retraction of the eye with elevation deficit (“pseudoretraction”) will disappear after inferior recession

■Convergent squint correction after decompression: consider lower dose e ects: unilateral medial rectus recession: 1 mm recession per 1.2° of intended squint angle reduction; bilateral rectus recession: 1 mm recession per 1.0° of intended squint angle reduction; consider medial rectus tendon elongation with a spacer for very large angles: 1 mm elongation per 0.9° of intended squint angle reduction

Dose e ect data are summarized in Table 16.5 [38, 40–42].

In most cases, it is possible to improve the field of binocular single vision. Over-corrections occur more often when the muscle is not directly fixed to the sclera but is

adjusted on the following day. This probably occurs due to adaptation of the muscles to changed tension during the operation. Post-operative tone increase occurs in structures that were previously relaxed, e.g., the antagonist and the “passive orbital tissue.” They return to their original tension, which leads to a further globe rotation against the direction of the recession. Therefore, the e ect of squint angle reduction increases significantly within the first postoperative month.

Persistent diplopia in extreme gaze is common, which is usually tolerable in upgaze, since the used gaze field is larger in downgaze than in upgaze.

Success rates (ocular alignment within about 2–3° in primary position) are similar for the di erent approaches and vary mainly between 60 and 80% for horizontal squint and up to 90% for vertical squint.

16.3.2.3 Lid Surgery

The most common indication for lid surgery in GO is upper lid retraction due to levator muscle fibrosis. Genuine lid retraction has to be discriminated from pseudo-lid retraction due to fibrosis of the inferior rectus muscle. The latter resolves after inferior rectus recession. Lower lid lengthening is indicated in lower lid retraction following inferior rectus recession. Bilateral lower lid retraction with proptosis should primarily be referred for orbital decompression. Another indication for eyelid surgery is increased preaponeurotic and subdermal fat, resulting in bulging eye lids. This may be treated during blepharoplasty when redundant lid skin is excised (review of the literature: [35, 43]).

Upper lid lengthening: Many di erent techniques for lenghthening the upper eyelids have been described. Among these are techniques with or without implants. In most cases, use of implants is not necessary. These are Müllerotomy or recession, medial or lateral levator aponeurosis recession, lateral horn cut (important for lateral flare), medial and lateral full thickness levator-, Müller-muscle-, and conjunctival recession. Since lateral retraction (temporal flare) is the most important aspect of upper lid retraction in patients with Graves orbitopathy, division of the lateral horn of the aponeurosis is necessary in most cases. Sutures may be placed between the tarsal plate and the detached aponeurosis to prevent spontaneous disinsertion. When sutures are used, it is important to protect the cornea, e.g., using the conjunctiva as a cover. Myotomies without spacers (grafts) require patient cooperation. If compliance is poor or marked fibrosis is present, spacers may be used. The vertical height of the implant should be approximately twice the measured eyelid retraction or measured eyelid retraction +2 mm, respectively. Patients examples before and after upper lid lengthening without and with implant are shown in Fig. 16.4. The implant is used in a patient with severe GO (after three wall decompression for DON) with marked fibrosis of levator palpebrae muscle. Correction of upper lid retraction is successful when 1–2 mm of the superior cornea is covered, the lid margin contour is smooth, when upper lid skin crease is between 7 and 10 mm, and lids are symmetric. Most of the surgical procedures are ascribed success rates of about 70–80%. Asymmetry can occur due to overor undercorrection, lid crease recession, and a thickened eyelid after use of a graft.

Lower lid lengthening: To correct lid retraction exceeding 1 mm, a “spacer” between lower lid retractors and tarsus is required (Fig. 16.5). Various organic and anorganic materials have been used as spacers. These include auricular cartilage, hard palate mucosa, expanded polyethylene Medpor microplates, autogenous tarsus transplants, porcine acellular dermal matrix, and donor sclera or pericardium. The vertical expansion of the spacer should amount to 3 times the lid retraction in mm. Most spacers, except hard palate mucosa, need to be covered with conjunctiva. The lower lid retractors are accessible either by anterior subciliary or posterior subtarsal transconjunctival approach. The e ect of lower lid lengthening can be increased by

lateral tarsal strip or tarsorrhaphy. Undercorrection is common.

Upper and lower lid blepharoplasty: Upper lid debulking and blepharoplasty is the final surgical procedure in the functional and cosmetic rehabilitation of the GO patient. Redundant skin and fat can be excised using scissors and bipolar cauterant, laser, or monopolar cauterization needle. In the lower lid, the skin excision should be modest to avoid lower lid retraction or ectropion. It is important to remove preaponeurotic fat (Fig. 16.6) and even subdermal fat together with the orbicularis muscle. Prolapsing lower lid fat can also be removed transconjunctivally in patients without excess skin.

Sutures for stabilisation of the interponate

a

b

f

Summary for the Clinician

■Disfiguring proptosis can be reduced through orbital decompression. Various surgical techniques are available. The amount of reduction depends on the number of walls removed and whether or not fat is removed. Removal of the medial wall is accompanied with the highest and removal of the lateral wall with the lowest risk of postoperative diplopia. If muscle restriction is present preoperatively, the risk of postoperatively deteriorated ocular motility is increased.

■The basic concept for eye muscle surgery in GO is recession of the fibrotic muscle. Di erent approaches are possible: preoperatively determined recession distances according to dose– e ect curves and intraoperative determination of recession distance via active or passive motility and adjustable sutures. Success rates are high.