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■ The major pitfall is to overlook masked bilaterality. Presence of a “V” pattern and a large extorsion indicates bilaterality. Consider bilateral surgery in such cases despite the absence of
15 apparent inferior oblique overaction and superior oblique underaction.
■Inferior oblique weakening alone provides satisfactory outcome in most of the cases if the vertical deviation does not exceed 15 prism diopters.
■Ipsilateral superior rectus and contralateral inferior rectus weakening procedures should always be considered in combination with inferior oblique weakening.
■Do not consider superior oblique tuck surgery in acquired ones. The risk for symptomatic iatrogenic Brown syndrome is very high. Superior oblique tendon tuck should be reserved for congenital cases with abnormal tendon laxity and a large vertical deviation.
■Fells modified Harada-Ito procedure is a surgery for acquired bilateral cases with marked torsional component.
15.4Sixth Nerve Palsy
Lateral rectus underaction, esotropia, and a horizontal diplopia, which is more prominent at distance, and abnormal head posture in unilateral cases keeping the a ected eye in adduction are the clinical features of sixth nerve palsy. Lateral rectus underaction may be very subtle in partially a ected cases and it is essential to measure the deviation in nine positions of gaze. Partially a ected cases benefit from prisms. Addition of prisms only on distance glasses are enough in most of the cases.
Botulinum toxin has a major role in treatment of sixth nerve palsy both for diagnostic and therapeutic purposes. During acute stage, injection of BTXA into the medial rectus muscle of the a ected eye provides a symptomatic relief. Although it was previously proposed that BTXA increased the possibility of spontaneous recovery, randomized clinical trials demonstrated that BTXA injection does not alter the chance of spontaneous recovery, but provides a rapid symptomatic relief of diplopia [34–38]. In chronic stage in mild partial cases BTXA injection alone may provide a satisfactory improvement of the deviation.
For a correct surgical plan, one needs to have the correct answers for the following questions:
■What is the amount of the measurement of the deviation in primary position?
■Is the paralysis total or partial?
■Are there any medial rectus contracture?
Surgical methods of treatment may be summarized as follows:
■Medial rectus recession and lateral rectus resection.
■Medial rectus weakening of the sound eye.
■BTXA injection into the medial rectus muscle + vertical rectus muscle transposition.
■Medial rectus recession + vertical rectus muscle transposition: This method carries a risk of anterior segment ischemia. That risk may be reduced by ciliary artery preserved full tendon transposition, performing the surgery in two divided sessions leaving at least 3 months between two operations, or by performing a partial vertical rectus transposition.
■If there is bilateral involvement, surgery should be performed in both eyes.
Medial rectus recession and lateral rectus resection:
Recess–resect should be reserved only for those with a good residual function of the a ected lateral rectus muscle. If the residual function of the lateral rectus muscle is very limited, then transposition will work better than recess–resect procedure. The correct surgical decision for a recess–resect or a transposition procedure is highly important. A wrong decision for a recess–resect procedure in an old patient makes the patient lose his or her chance to have a transposition procedure because of the significant risk of anterior segment ischemia. To obtain a more reliable assessment for the residual lateral rectus function, BTXA injection is recommended as a first line treatment and the rest of the treatment plan is made according to the results that are obtained by BTXA injection [3, 39] (Fig. 15.9).
In cases with a significant limitation of ocular motility, BTXA provides the assessment of the residual function of the paretic muscle in the absence of secondary fibrotic changes in medial rectus muscle. If there is no improvement in abduction following a relaxation of the medial rectus muscle by BTXA, it indicates that lateral rectus muscle is totally dead and a transposition is required. We evaluate the ocular motility 1 week after the BTXA injection and if there is no improvement on abduction, we perform full tendon width vertical rectus muscle transposition during the maximal BTXA e ect. This method reduces the risk for anterior segment ischemia.
Medial rectus weakening of the sound eye: Medial rectus recession or faden operation of the medial rectus muscle
•Botulinum toxin injection as the first line treatment
•Cure-no further treatment
•Patient satisfied - regular injections
•Unsatisfactory result - necessary information for recess-resect or transposition surgery
Fig 15.9 T he use of BTXA for planning of treatment in sixth nerve palsy [3]
of the sound eye increases the area of binocular diplopiafree field. A combination of recession and resection of the medial rectus muscle provides an adjustable faden e ect in the medial rectus muscle and may prove to be useful to reduce the symptoms of the patient with more control compared with conventional faden operation [43].
The problems of treatment in sixth nerve palsy are the anterior segment ischemia risk and the insu cient correction because of a recess–resect procedure in a non functioning lateral rectus muscle.
Summary for the Clinician
■The correct diagnosis of partial and total sixth nerve palsy is the pearl for a successful outcome of surgery.
■The major pitfall is the misinterpretation of the lateral muscle function because of the secondary medial rectus restriction in long-standing cases.
■BTXA has major role both for surgical planning and as an adjunct to surgery.
■Recess–resect procedure works only in ones with good residual function of the lateral rectus muscle. Consider vertical rectus transposition without augmentation sutures in ones with very limited evidence of lateral rectus muscle function. Augmentation sutures increases the e ect of transposition and should better be used in ones with a totally dead lateral rectus muscle.
■To reduce the problems of vertical rectus muscle transposition procedure keep parallel to the spiral of Tillaux.
References 205
References
1.Golnik KC, Miller NR (1991) Late recovery of function after oculomotor nerve palsy. Am J Ophthalmol 111: 566–570
2.Ansons AM, Davis H (2001) Diagnosis and management of ocular motility disorders, 3rd edn. Oxford, Blackwell Science, Paris Berlin Tokyo, pp 143–162
3.Özkan SB (2006) Strategies of treatment in paralytic strabismus. Türkiye Klinikleri J Surg Med Sci 2:58–65
4.Demer JL, Miller JM, Poukens V, et al (1995) Evidence for fibromuscular pulleys of the recti extraocular muscles. Invest Ophthalmol Vis Sci 36:1125–1136
5.Demer JL, Miller JM, Poukens V (1996) Surgical implications of the rectus extraocular muscle pulleys. J Pediatr Ophthalmol Strabismus 33:208–218
6.Özkan SB, Dayanir V, Kir E, et al (2001) Role of botulinum toxin A in management of acquired loss of fusion. In: de Faber JT (ed) Transactions 27th meeting of the European strabismological association. Swets and Zeitlinger, The Netherlands, pp 195–198
7.Gottlob IG, Catalano R, Reinecke RD (1991) Surgical management of oculomotor nerve palsy. Am J Ophthalmol 111:71–76
8.Morad Y, Kowal L, Scott AB (2005) Lateral rectus muscle disinsertion and reattachment to the lateral orbital wall. Br J Ophthalmol 89:983–985
9.Velez FG, Thacker N, Britt MT, et al (2004) Rectus muscle orbital wall fixation: a reversible profound weakening procedure. J AAPOS 8:473–480
10.Heo H, Park SW (2008) Rectus muscle posterior tenon fixation as an inactivation procedure. Am J Ophthalmol 146:310–317
11.Young TL, Conahan BM, Summers CG, et al (2000) Anterior transposition of the superior oblique tendon in the treatment of oculomotor nerve palsy and its influence on postoperative hypertropia. J Pediatr Ophthalmol Strabismus 37:149–155
12.Salazar Leon JA, Ramirez-Ortiz MA, Salas-Vargas M (1998) The surgical correction of paralytic strabismus using fascia lata. J Pediatr Ophthalmol Strabismus 35: 27–32
13.Villasenor Solares J, Riemann BI, Romanelli Zuazo AC, et al (2000) Ocular fixation to nasal periosteum with a superior oblique tendon in patients with third nerve palsy. J Pediatr Ophthalmol Strabismus 37:260–265
14.Daniell MD, Gregson RM, Lee JP (1996) Management of fixed divergent squint in third nerve palsy using traction sutures. Aust N Z J Ophthalmol 24:261–265
15.Khaier A, Dawson E, Lee J (2008) Traction sutures in the management of long standing third nerve palsy. Strabismus 16:77–83
206 |
15 Pearls and Pitfalls in Surgical Management of Paralytic Strabismus |
16.Helveston EM, Krach D, Plager DA, et al (1992) A new classification of superior oblique palsy based on congenital variations of the tendon. Ophthalmology 99:1609–1615
17.Plager DA (1990) Traction testing in superior oblique
15 |
palsy. J Pediatr Ophthalmol Strabismus 27:136–140 |
18.Plager DA (1992) Tendon laxity in superior oblique palsy. Ophthalmology 99:1032–1038
19.Wallace DK, von Noorden GK (1994) Clinical characteristics and surgical management of congenital absence of the superior oblique tendon. Am J Ophthalmol 118:63–69
20.Özkan SB, Aribal ME, Sener EC, et al (1997) Magnetic resonance imaging in evaluation of congenital and acquired superior oblique palsy. J Pediatr Ophthalmol Strabismus 34:29–34
21.Sato M. Magnetic resonance imaging and tendon anomaly associated with congenital superior oblique palsy (1999) Am J Ophthalmol 127:379–387
22.Guyton DL (1981) Exaggerated traction test for the oblique muscles. Ophthalmology 88:1035–1040
23.Ase AJ, Munoz M (1998) Outcome of surgery for superior oblique palsy with contracture of ipsilateral superior rectus treated by superior rectus recession. Binocul Vis Strabismus Q 13:177–180
24.Mims JL (2003) The triple forced duction test(s) for diagnosis and treatment of superior oblique palsy with an updated flow chart for unilateral superior oblique palsy. Binocul Vis Strabismus Q18:15–24
25.Kushner BJ (1988) The diagnosis and treatment of bilateral masked superior oblique palsy. Am J Ophthalmol 105: 186–194
26.Price NC, Vickers S, Lee JP, et al (1987) The diagnosis and surgical management of acquired bilateral superior oblique palsy. Eye 1:78–85
27.Hatz KB, Brodsky MC, Killer HE (2006) When is isolated inferior oblique muscle surgery an appropriate treatment for superior oblique palsy? Eur J Ophthalmol 16:10–16
28.Hussein MA, Stager DRSr, Beauchamp GR, et al (2007) Anterior and nasal transposition of the inferior oblique muscle. J AAPOS 11:29–33
29.Özkan SB, Can D, Demirci S, et al (1995) Surgical treatment in congenital superior oblique palsy. Türkiye Klinikleri. J Surg Med Sci 4:223–226
30.Roberts C, Dawson E, Lee J (2002) Modified Harada-Ito procedure in bilateral superior oblique paresis. Strabismus 10:211–214
31.Sprunger DT, Helveston EM (1993) Progressive overcorrection after inferior rectus recession. J Pediatr Ophthalmol Strabismus 30:145–148
32.Lozano-Pratt A, Estanol B (1994) Treatment of acute paralysis of the fourth cranial nerve by botulinum toxin A chemodenervation. Binocul Vis Strabismus Q 9:155–168
33.Garnham L, Lawson JM, O’Neill D, et al (1997) Botulinum toxin in fourth nerve palsies. Aust N Z J Ophthalmol 25:31–35
34.Holmes JM, Beck RW, Kip KE, et al (2000) Botulinum toxin treatment versus conservative management in acute traumatic sixth nerve palsy or paresis. J AAPOS 4:145–149
35.Lee J, Haris S, Cohen J, et al (1994) Results of a prospective randomized trial of botulinum toxin therapy in acute unilateral sixth nerve palsy. J Pediatr Ophthalmol Strabismus 31:283–286
36.Metz HS, Masow M (1988) Botulinum toxin treatment of acute sixth and third nerve palsy. Graefe’s Arch Clin Exp Ophthalmol 226:141–144
37.Murray ADN (1991) Early botulinum toxin treatment of acute sixth nerve palsy. Eye 5:45–47
38.Repka MX, Lam GC, Morrison NA (1994) The e cacy of botulinum neurotoxin A for the treatment of complete and partially recovered chronic sixth nerve palsy. J Pediatr Ophthalmol Strabismus 31:79–83
39.Riordian PR, Lee JP (1992) Management of VIth nerve palsy – avoiding unnecessary surgery. Eye 386–390
40.Kraft SP, O’Reilly C, Quigley PL, et al (1993) Cyclotorsion in unilateral and bilateral superior oblique paresis. J Pediatr Ophthalmol Strabismus 30:361–367
41.von Noorden GK, Murray E, Wong SY (1986) Superior oblique paralysis: a review of 270 cases. Arch Ophthalmol 104:1771–1776
42.von Noorden GK, Campos EC (2002) Binocular vision and ocular motility, 6th edn. Mosby, St. Louis, USA pp 559–565
43.Dawson E, Boyle N, Taherian K, et al (2007) Use of a combined recession and resection of a rectus muscle procedure in the management of incomitant strabismus. J AAPOS 11:131–134