Surgical Solutions for Supranuclear and Internuclear Ocular Motility Problems G. Robert LaRoche, M.D., F.R.C.S.C. INTRODUCTION An increasing number of patients are surviving with debilitating neurological diseases. This final article of the symposium will discuss the place of strabismus surgery in the management of these patients, especially when there is an ocular motility problem of central origin that is not limited to cranial fourth, sixth, or third nerves, or one that involves the muscles themselves. It will discuss how we can use extraocular muscle surgery to treat complex ocular movement problems associated with brain or muscle disease. DEFINING THE PROBLEM Acquired supranuclear or internuclear ocular motility problems, volitional or vestibulo-cerebellar ocular motility control deficits, and central nystagmus all include normal extraocular muscles with normal neuromuscular junctions. Therefore, exFrom the Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada. Requests for reprints should be addressed to: G. Robert LaRoche, M.D., F.R.C.S.C., Dept. of Ophthalmology and Visual Sciences, Dalhousie University, 5850 University Ave., Halifax, Nova Scotia, Canada B3K 6R8; e-mail: [email protected] Presented in part at the International Strabismological Association (ISA) symposium on Eye Movement Disorders at the XII International Orthoptic Congress, Toronto, Canada, June 26-29, 2012.
cept for the fine control of their actions, strabismus surgeons have found that these same muscles respond well to traditional strabismus surgery and surgical dosages. Furthermore, sensory fusion is often preserved in many of these patients, further facilitating the restoration of useful single binocular vision with surgery. However, fragile motor control and limited motor fusional amplitudes do limit certain expectations in these patients. In contrast, myasthenia gravis and mitochondrial diseases are two situations where surgical intervention is not typically entertained for diplopia. Here, the very substrate of our intervention is abnormal: the neuromuscular junction, or the contractile unit itself. Despite reluctance by some surgeons to use muscle surgery, our experience has shown that there is a place for surgery in these patients as well. Patients who have suffered head trauma, undergone neurosurgical intervention, or lost some oculomotor function due to vascular events or infectious, demyelinating, or para-neoplastic central nervous processes can all be left with permanent diplopia, oscillopsia, or a decreased ability to direct their gaze. These symptoms are the results of acquired supra- or internuclear ophthalmoplegia, supranuclear eye movement control disruption, gaze and vergence weaknesses, or nystagmus. Over the years, strabismologists have explored surgical means of helping these patients. Small
© 2013 Board of Regents of the University of Wisconsin System, American Orthoptic Journal, Volume 63, 2013, ISSN 0065-955X, E-ISSN 1553-4448
American Orthoptic Journal
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OCULAR MOTILITY
series have been published, with varying follow-up intervals, and various surgical approaches have been suggested.1-5 The cumulative experience from these reports suggests that to optimize surgical success: preoperative stability is essential, preservation of fusion ability is necessary for the restoration of binocular functions, and the treatment paradigm has to be tailored to each patient’s needs. This includes regaining single binocular vision in a key field of gaze, or improvement of a severe head posture with centration of vision of the preferred eye. More than one surgery is often necessary, and prisms are often used to “fine tune” the results. While the techniques described are all part of the conventional armamentarium of muscle surgery, including resections, recessions, transpositions, and adjustable sutures, their novel applications in these challenging cases is what makes them uniquely useful. INTERNUCLEAR OPHTHALMOPLEGIA (INO) AND SKEW DEVIATION In unilateral cases of INO, the abducting nystagmic lateral rectus can give rise to oscillopsia while the adduction deficit will be responsible for diplopia. This combination can be responsible for an uncomfortable head turn. Bilateral cases will generally cause diplopia that is worse at near. In unilateral cases, a combination of ipsilateral lateral rectus recession and contralateral lateral rectus posterior fixation will help realign the eyes in the primary position and decrease the lateral rectus nystagmus and secondary over-action. In bilateral cases, when an exotropia is present, a unilateral or bilateral lateral rectus recess and medial rectus resect or tuck will be useful.1, 3, 5 Transpositions to increase the adduction in unilateral or bilateral cases of internuclear ophthalmoplegia have been proposed when there is a “moderate adduction limitation.”4 Over-
70
all, however, the benefits or indications of a specific combination, based on angle or saccade weakness of the adducting eye are not clear from the limited series published. In case of persisting skew deviation(s), a straightforward vertical surgery to the inferior rectus can address a maximal deviation in down-gaze, but the resulting torsional effect might need correcting by transposing the muscle horizontally. This can also be useful in alternating hypertropia skew where both inferior rectus muscles can be operated upon, but with the same considerations regarding torsion. Brodsky also highlights the clinical significance of small vertical diplopia caused by persistent skew deviation, which may have to be addressed.6 PARINAUD SYNDROME AND GAZE PALSIES These are a complex group with different causes. Once the condition is chronic and stable, it is worth investing the necessary time and effort for a thorough surgical evaluation to help these patients. Vertical gaze palsies are frequent, and these patients will also adopt a chin-up posture to facilitate fixation. Recession of both inferior rectus muscles will be beneficial to these patients. However, some of these cases will also have a nuclear palsy: for example, a fourth cranial nerve that will create torsional diplopia of clinical significance. Others will have overwhelmingly complex motility problems. However, some solutions do exist, as shown in the following case. CASE REPORT A young paramedic suffered a dramatic paraneoplastic meningitis secondary to testicular cancer. This resulted in a complete vertical gaze paralysis with a marked tonic vestibular up-gaze deviation and asymmetrical sixth- and fourth-nerve paresis. In this marked preferred up-gaze position, he could fuse. He could not move his eyes voluntarily more than few de-
Volume 63, 2013
LAROCHE
grees away from this position without noting diplopia. He also had marked nystagmus with any down-gaze efforts. A bilateral combined vertical surgery on all four vertical rectus muscles with horizontal transposition lowered his fusion zone and led to a good primary position alignment. Revising the position of one inferior rectus helped deal with a residual vertical and torsional misalignment. The patient is now mobile again, and he can hold his head in primary position with comfort.
ACQUIRED NYSTAGMUS WITH OSCILLOPSIA These problems can be approached in the same way as infantile nystagmus. There are now in the literature many reports of beneficial “nystagmus surgery” techniques that have been successfully applied to acquired nystagmus. For cases of horizontal nystagmus these include bilateral single muscle recessions (Anderson procedure), bilateral (four-muscle) recession and resection (Kestenbaum surgery), and tenotomies and reattachment of the horizontal muscles. For vertical nystagmus, one can consider recessions of vertical rectus muscles with weakening of oblique muscles. For cases of periodic alternating nystagmus, tenotomies and reattachment or large recessions of the horizontal rectus muscles can be effective. However, coinciding gaze or cranial nerve palsies will complicate matters. Intramuscular botulinum toxin can sometimes help assess the effect of a weakening procedure alone on both the nystagmus and gaze dependence before a more definitive surgery is carried out. CHRONIC PROGRESSIVE EXTERNAL OPHTHALMOPLEGIA (CPEO) CPEO is a progressive and debilitating condition. The unrelenting course would at first discourage any consideration of a surgical treatment. However, a progressively blinding ptosis can require treatment in
American Orthoptic Journal
these patients. Similarly, debilitating bilateral exotropia with poor eye movement can also cause major vision disability in CPEO patients: many will have to adopt a severe head turn forced on them by a nearly immobile exotropic fixating eye. These patients will benefit from aggressive horizontal surgery even if restoring their binocular vision is nearly impossible. The result will be somewhat temporary, but is certainly of great benefit for these unfortunate individuals, especially in the advanced stages of their disease. As an adjunct to a large medial rectus resection or tuck, botulinum toxin in the abducting lateral rectus instead of a very large recession can be considered here, allowing easier repeated interventions as they become necessary with the progress of the disease. MYASTHENIA GRAVIS While not a disorder of central origin, myasthenia gravis can also have relentless progression, and it is a cause of debilitating diplopia. It is also not typically considered a condition amenable to ocular muscle surgery. However, individuals with good control by medical treatment will benefit from periods of stable ocular alignment, some for years. Surgery then becomes an option, but, again, with a realistic goal in mind. For some of these patients, due to incomitancy or size of deviation, prisms are not an option. However, with medically controlled disease, muscle function may be sufficient to respond to conventional strabismus surgery. Additionally, good sensory fusion and measurable motor fusional amplitudes can be harbingers of satisfactory surgical outcome for these patients. In the short term, the unpredictability of the result can be minimized with the use of adjustable sutures to help avoid immediate postoperative over- or under-corrections. The longevity of the result will also be unpredictable, and will certainly depend on the continued stability of the medical
71
OCULAR MOTILITY
control of the systemic disease. The same considerations will apply in those rare cases of mitochondrial diseases. In these cases, sometimes strabismus surgery has to be timed with concurrent ptosis surgery, which is necessary to preserve sight.
2.
3.
CONCLUSION
4.
Established strabismus surgical techniques can be beneficial to quite a few patients with diplopia due to diseases of extraocular muscles and of the central nervous system. Great improvements in patient quality of life can be accomplished. All members of the eye care team, including orthoptists, must remind neurologists, neurosurgeons, rehabilitation physicians, and therapists that a growing number of patients with these conditions can benefit from our interventions.
5.
6.
exotropia in multiple sclerosis. J AAPOS 2009; 13:13-15. Buckley GE, Holgado S: Surgical treatment of up-gaze palsy in Parinaud’s syndrome. J AAPOS 2004; 8:249-253. Buckley SA, Elston JS: Surgical treatment of supranuclear and internuclear ocular motility disorders. Eye 1997; 11:377-380. Nathan N, Donahue S: Transposition surgery for internuclear ophthalmoplegia. J Pediatr Ophthalmol Strabismus 2012; 49:378-381. Roper-Hall G, Cruz OA, Chung SM: Results of extraocular muscle surgery in WEBINO bilateral internuclear ophthalmoplegia patients. J AAPOS 2008; 12:277-281. Brodsky MC: Surgical treatment of vertical ocular motility disorders of supranuclear origin. Am Orthopt J 2011; 61:28-32.
Key words: gaze palsies, infranuclear, ophthalmoplegia, myasthenia, supranuclear, strabismus surgery
REFERENCES 1. Adams WE, Leavitt JA, Holmes JM: Strabismus surgery for internuclear ophthalmoplegia with
72
Volume 63, 2013
cept for the fine control of their actions, strabismus surgeons have found that these same muscles respond well to traditional strabismus surgery and surgical dosages. Furthermore, sensory fusion is often preserved in many of these patients, further facilitating the restoration of useful single binocular vision with surgery. However, fragile motor control and limited motor fusional amplitudes do limit certain expectations in these patients. In contrast, myasthenia gravis and mitochondrial diseases are two situations where surgical intervention is not typically entertained for diplopia. Here, the very substrate of our intervention is abnormal: the neuromuscular junction, or the contractile unit itself. Despite reluctance by some surgeons to use muscle surgery, our experience has shown that there is a place for surgery in these patients as well. Patients who have suffered head trauma, undergone neurosurgical intervention, or lost some oculomotor function due to vascular events or infectious, demyelinating, or para-neoplastic central nervous processes can all be left with permanent diplopia, oscillopsia, or a decreased ability to direct their gaze. These symptoms are the results of acquired supra- or internuclear ophthalmoplegia, supranuclear eye movement control disruption, gaze and vergence weaknesses, or nystagmus. Over the years, strabismologists have explored surgical means of helping these patients. Small
© 2013 Board of Regents of the University of Wisconsin System, American Orthoptic Journal, Volume 63, 2013, ISSN 0065-955X, E-ISSN 1553-4448
American Orthoptic Journal
69
OCULAR MOTILITY
series have been published, with varying follow-up intervals, and various surgical approaches have been suggested.1-5 The cumulative experience from these reports suggests that to optimize surgical success: preoperative stability is essential, preservation of fusion ability is necessary for the restoration of binocular functions, and the treatment paradigm has to be tailored to each patient’s needs. This includes regaining single binocular vision in a key field of gaze, or improvement of a severe head posture with centration of vision of the preferred eye. More than one surgery is often necessary, and prisms are often used to “fine tune” the results. While the techniques described are all part of the conventional armamentarium of muscle surgery, including resections, recessions, transpositions, and adjustable sutures, their novel applications in these challenging cases is what makes them uniquely useful. INTERNUCLEAR OPHTHALMOPLEGIA (INO) AND SKEW DEVIATION In unilateral cases of INO, the abducting nystagmic lateral rectus can give rise to oscillopsia while the adduction deficit will be responsible for diplopia. This combination can be responsible for an uncomfortable head turn. Bilateral cases will generally cause diplopia that is worse at near. In unilateral cases, a combination of ipsilateral lateral rectus recession and contralateral lateral rectus posterior fixation will help realign the eyes in the primary position and decrease the lateral rectus nystagmus and secondary over-action. In bilateral cases, when an exotropia is present, a unilateral or bilateral lateral rectus recess and medial rectus resect or tuck will be useful.1, 3, 5 Transpositions to increase the adduction in unilateral or bilateral cases of internuclear ophthalmoplegia have been proposed when there is a “moderate adduction limitation.”4 Over-
70
all, however, the benefits or indications of a specific combination, based on angle or saccade weakness of the adducting eye are not clear from the limited series published. In case of persisting skew deviation(s), a straightforward vertical surgery to the inferior rectus can address a maximal deviation in down-gaze, but the resulting torsional effect might need correcting by transposing the muscle horizontally. This can also be useful in alternating hypertropia skew where both inferior rectus muscles can be operated upon, but with the same considerations regarding torsion. Brodsky also highlights the clinical significance of small vertical diplopia caused by persistent skew deviation, which may have to be addressed.6 PARINAUD SYNDROME AND GAZE PALSIES These are a complex group with different causes. Once the condition is chronic and stable, it is worth investing the necessary time and effort for a thorough surgical evaluation to help these patients. Vertical gaze palsies are frequent, and these patients will also adopt a chin-up posture to facilitate fixation. Recession of both inferior rectus muscles will be beneficial to these patients. However, some of these cases will also have a nuclear palsy: for example, a fourth cranial nerve that will create torsional diplopia of clinical significance. Others will have overwhelmingly complex motility problems. However, some solutions do exist, as shown in the following case. CASE REPORT A young paramedic suffered a dramatic paraneoplastic meningitis secondary to testicular cancer. This resulted in a complete vertical gaze paralysis with a marked tonic vestibular up-gaze deviation and asymmetrical sixth- and fourth-nerve paresis. In this marked preferred up-gaze position, he could fuse. He could not move his eyes voluntarily more than few de-
Volume 63, 2013
LAROCHE
grees away from this position without noting diplopia. He also had marked nystagmus with any down-gaze efforts. A bilateral combined vertical surgery on all four vertical rectus muscles with horizontal transposition lowered his fusion zone and led to a good primary position alignment. Revising the position of one inferior rectus helped deal with a residual vertical and torsional misalignment. The patient is now mobile again, and he can hold his head in primary position with comfort.
ACQUIRED NYSTAGMUS WITH OSCILLOPSIA These problems can be approached in the same way as infantile nystagmus. There are now in the literature many reports of beneficial “nystagmus surgery” techniques that have been successfully applied to acquired nystagmus. For cases of horizontal nystagmus these include bilateral single muscle recessions (Anderson procedure), bilateral (four-muscle) recession and resection (Kestenbaum surgery), and tenotomies and reattachment of the horizontal muscles. For vertical nystagmus, one can consider recessions of vertical rectus muscles with weakening of oblique muscles. For cases of periodic alternating nystagmus, tenotomies and reattachment or large recessions of the horizontal rectus muscles can be effective. However, coinciding gaze or cranial nerve palsies will complicate matters. Intramuscular botulinum toxin can sometimes help assess the effect of a weakening procedure alone on both the nystagmus and gaze dependence before a more definitive surgery is carried out. CHRONIC PROGRESSIVE EXTERNAL OPHTHALMOPLEGIA (CPEO) CPEO is a progressive and debilitating condition. The unrelenting course would at first discourage any consideration of a surgical treatment. However, a progressively blinding ptosis can require treatment in
American Orthoptic Journal
these patients. Similarly, debilitating bilateral exotropia with poor eye movement can also cause major vision disability in CPEO patients: many will have to adopt a severe head turn forced on them by a nearly immobile exotropic fixating eye. These patients will benefit from aggressive horizontal surgery even if restoring their binocular vision is nearly impossible. The result will be somewhat temporary, but is certainly of great benefit for these unfortunate individuals, especially in the advanced stages of their disease. As an adjunct to a large medial rectus resection or tuck, botulinum toxin in the abducting lateral rectus instead of a very large recession can be considered here, allowing easier repeated interventions as they become necessary with the progress of the disease. MYASTHENIA GRAVIS While not a disorder of central origin, myasthenia gravis can also have relentless progression, and it is a cause of debilitating diplopia. It is also not typically considered a condition amenable to ocular muscle surgery. However, individuals with good control by medical treatment will benefit from periods of stable ocular alignment, some for years. Surgery then becomes an option, but, again, with a realistic goal in mind. For some of these patients, due to incomitancy or size of deviation, prisms are not an option. However, with medically controlled disease, muscle function may be sufficient to respond to conventional strabismus surgery. Additionally, good sensory fusion and measurable motor fusional amplitudes can be harbingers of satisfactory surgical outcome for these patients. In the short term, the unpredictability of the result can be minimized with the use of adjustable sutures to help avoid immediate postoperative over- or under-corrections. The longevity of the result will also be unpredictable, and will certainly depend on the continued stability of the medical
71
OCULAR MOTILITY
control of the systemic disease. The same considerations will apply in those rare cases of mitochondrial diseases. In these cases, sometimes strabismus surgery has to be timed with concurrent ptosis surgery, which is necessary to preserve sight.
2.
3.
CONCLUSION
4.
Established strabismus surgical techniques can be beneficial to quite a few patients with diplopia due to diseases of extraocular muscles and of the central nervous system. Great improvements in patient quality of life can be accomplished. All members of the eye care team, including orthoptists, must remind neurologists, neurosurgeons, rehabilitation physicians, and therapists that a growing number of patients with these conditions can benefit from our interventions.
5.
6.
exotropia in multiple sclerosis. J AAPOS 2009; 13:13-15. Buckley GE, Holgado S: Surgical treatment of up-gaze palsy in Parinaud’s syndrome. J AAPOS 2004; 8:249-253. Buckley SA, Elston JS: Surgical treatment of supranuclear and internuclear ocular motility disorders. Eye 1997; 11:377-380. Nathan N, Donahue S: Transposition surgery for internuclear ophthalmoplegia. J Pediatr Ophthalmol Strabismus 2012; 49:378-381. Roper-Hall G, Cruz OA, Chung SM: Results of extraocular muscle surgery in WEBINO bilateral internuclear ophthalmoplegia patients. J AAPOS 2008; 12:277-281. Brodsky MC: Surgical treatment of vertical ocular motility disorders of supranuclear origin. Am Orthopt J 2011; 61:28-32.
Key words: gaze palsies, infranuclear, ophthalmoplegia, myasthenia, supranuclear, strabismus surgery
REFERENCES 1. Adams WE, Leavitt JA, Holmes JM: Strabismus surgery for internuclear ophthalmoplegia with
72
Volume 63, 2013
