Ординатура / Офтальмология / Английские материалы / Strabismus Surgery and Its Complications_Coats, Olitsky_2007

mal width of the inferior oblique tendon, the insertion is usually clustered adjacent to the inferior rectus muscle insertion (>Fig. 11.13b). Suturing the inferior oblique muscle too far anterior to the inferior rectus muscle or spreading the insertion out too broadly has been suggested as a cause of unwanted restrictive strabismus following surgery [14]. The conjunctiva is then closed with interrupted absorbable sutures. It is not uncommon for physicians and/or patients to be aware of subtle and sometimes obvious changes in the contour of the lower eyelid following inferior oblique anterior transposition [15] (Chap. 26).

11.2.7Technique for Nasal Myotomy of the Inferior Oblique Muscle

Stager and coworkers [16] reported a technique for nasal myotomy of the inferior oblique muscle for recurrent inferior oblique overaction. The procedure involves removal of a 5-mm segment from the nasal portion of the inferior oblique muscle, leaving the remaining temporal portion of the muscle and the neurovascular junction intact. These authors reported reduction in residual inferior oblique overaction in 95% of patients, with complete elimination of overaction in many patients.

An inferonasal fornix conjunctival incision is made and carried down to bare sclera. The inferior rectus muscle is isolated from its nasal border and the eye retracted superiorly. The inferior oblique muscle is identified in Tenon’s capsule and is seen to abruptly narrow nasal to the inferior rectus muscle. The nasal portion of the inferior oblique muscle is isolated on one or two small hooks Two hemostats separated by approximately 5 mm are placed across the muscle and the segment of muscle between the hemostats removed with sharp dissection. The cut edges of the muscle are cauterized and the distal segment of muscle is placed into the posterior Tenon’s capsule. Any openings seen in Tenon’s capsule are sutured closed to reduce the risk of fat intrusion into the surgical site. The conjunctiva is closed with absorbable suture.

felt the procedure was particularly successful in patients with recurrent congenital or acquired superior oblique palsy, particularly as a secondary procedure.

After exposure, isolation, and dissection of the distal portion of the inferior oblique muscle in the inferotemporal orbit, the insertion of the muscle is transposed inferior to the inferior rectus muscle to the nasal side of the inferior rectus muscle. The posterior-temporal fibers are sutured 2 mm nasal and 2 mm posterior to the nasal border of the inferior rectus muscle insertion and the anterior-temporal fibers are sutured 3 mm nasal to this position (>Fig. 11.14). Nonabsorbable sutures are recommended for securing the muscle to the sclera, because the posterior-temporal fibers of the muscle are under enough tension to slip after the tensile strength of absorbable sutures is lost.

Fig. 11.13a,b. Inferior oblique muscle anterior transposition. a The new insertion of the muscle is placed 1 mm anterior or posterior and adjacent to the temporal border of the inferior rectus muscle insertion. b The insertion should not be spread out, as this can result in unwanted duction abnormalities postoperatively

11.2.8Technique for Anterior

and Nasal Transposition of the Inferior Oblique Muscle

Stager and coworkers [17, 18] reported anterior and nasal transposition of the inferior oblique muscle. The procedure was utilized on patients with inferior oblique overaction, superior oblique palsy, absent superior oblique muscles, anti-eleva- tion syndrome, and Duane syndrome with significant upshoots and downshoots in adduction. All of their patients had one or more of the following signs including overelevation in adduction, exotropia in up gaze, an abnormal head posture, and/or excyclotorsion. The procedure was said to work favorably in all patients except those with Y-pattern exotropia. The procedure was found to eliminate up shoots in Duane syndrome, but shown to worsen down shoots in some patients. These authors

Fig. 11.14. Anterior and nasal transposition of the inferior oblique muscle. After isolating and disinserting the muscle in the inferotemporal quadrant of the orbit, the posterior-temporal fibers are sutured 2 mm nasal and 2 mm posterior to the nasal border of the inferior rectus muscle insertion and the anterior-temporal fibers are sutured 3 mm nasal to this position using nonabsorbable sutures

Procedures to enhance the function of the inferior oblique muscle are rarely indicated. However, such procedures might be indicated in two particular situations. The first is severe incyclotorsion or residual incyclotorsion despite attempted surgical correction by other means. Freedman and coworkers [19, 20] reported use of inferior oblique advancement combined with superior oblique tenotomy to treat incyclotorsion caused by macular translocation surgery. The second possible indication is persistent inferior oblique underaction in patients with inferior oblique muscle palsy despite previous surgical intervention. It should be noted that some people consider anterior transposition of the inferior oblique muscle to be a “strengthening” procedure of the inferior oblique muscle.

After exposure,isolation,and dissectionofthecapsule,a tucking procedure can be performed. The muscle is tucked by passing 6-0 absorbable or nonabsorbable suture to plicate the muscle in the inferotemporal quadrant of the orbit (>Fig. 11.16).

11.3.1Technique for Advancement of the Inferior Oblique Muscle With and Without Resection

After exposure, isolation, dissection, and disinsertion of the inferior oblique muscle at its insertion as described above, the inferior oblique muscle is advanced distally, parallel to its normal course along the globe. It is then reinserted into the sclera typically at or above the border of the lateral rectus muscle (>Fig. 11.15). Resection of the distal end of the inferior oblique muscle ranging from approximately 5 mm to 10 mm can be done to further enhance the effect of the procedure. The conjunctiva is closed with interrupted absorbable suture.

Fig. 11.16. Tucking procedure of the inferior oblique muscle. The muscle is tucked using 6-0 absorbable or nonabsorbable suture to plicate the muscle

Fig. 11.15. Advancement of the inferior oblique muscle with and without resection. The inferior oblique muscle is advanced forward, parallel with its normal course, and sutured to the sclera above the

lateral rectus muscle border. A small to medium resection can be performed to enhance the effect of the advancement

References

1.Wertz RD, Romano PE, Wright P (1977) Inferior oblique myectomy, disinsertion, and recession in rhesus monkeys. Arch Ophthalmol 95:857–860

2.Helveston EM, Cofield DD (1970) Indications for marginal myotomy and technique. Am J Ophthalmol 70:574–578

3.Stager DR (1996) The neurofibrovascular bundle of the inferior oblique muscle as its ancillary origin. Trans Am Ophthalmol Soc 94:1073–1094

11.Gamio S, Tartara A, Zelter M (2002) Recession and anterior transposition of the inferior oblique muscle [RATIO] to treat three cases of absent inferior rectus muscle. Binocul Vis Strabismus Q 17:287–295

12.Polati M, Gomi C (2002) Recession and measured, graded anterior transposition of the inferior oblique muscles for V-pattern strabismus: outcome of 44 procedures in 22 typical patients. Binocul Vis Strabismus Q 17:89–94

13.Minguini N, de Carvalho KM, de Araujo L, Crosta C (2004) Anterior transposition compared to graded recession of the inferior oblique muscle for V-pattern strabismus. Strabismus 12:221–225

tion and resection of the inferior oblique muscle for the treatment of hypertropia. J Pediatr Ophthalmol Strabismus 42:163–165

5.Bothun ED, Summers CG (2004) Unilateral inferior oblique anterior transposition for dissociated vertical deviation. J AAPOS 8:259–263

6.Goldchmit M, Felberg S, Souza-Dias C (2003) Unilateral anterior transposition of the inferior oblique muscle for correction of hypertropia in primary position. J AAPOS 7:241–243

7.Gonzalez C, Cinciripini G (1995) Anterior transposition of the inferior oblique in the treatment of unilateral superior oblique palsy. J Pediatr Ophthalmol Strabismus 32:107–113

8.Olitsky SE, Notaro S (2000) Anterior transposition of the inferior oblique for the treatment of a lost inferior rectus muscle. J Pediatr Ophthalmol Strabismus 37:50–51

9.Chang YH, Yeom HY, Han SH (2005) Anterior transposition of the inferior oblique muscle for a snapped inferior rectus muscle following functional endoscopic sinus surgery. Ophthalmic Surg Lasers Imaging 36:419–421

10.Aguirre-Aquino BI, Riemann CD, Lewis H, Traboulsi EI (2001) Anterior transposition of the inferior oblique muscle as the initial treatment of a snapped inferior rectus muscle. J AAPOS 5:52–54

ferior oblique anteriorization. J AAPOS 1:55–62

15.Kushner BJ (2000) The effect of anterior transposition of the inferior oblique muscle on the palpebral fissure. Arch Ophthalmol 118:1542–1546

16.Stager DR Jr., Wang X, Stager DR Sr., Beauchamp GR, Felius J (2004) Nasal myectomy of the inferior oblique muscles for recurrent elevation in adduction. J AAPOS 8:462–465

17.Stager DR Jr., Beauchamp GR, Wright WW, Felius J, Stager D Sr (2003) Anterior and nasal transposition of the inferior oblique muscles. J AAPOS 7:167–173

18.Stager DR Sr., Beauchamp GR, Stager DR Jr. (2001) Anterior and nasal transposition of the inferior oblique muscle: a preliminary case report on a new procedure. Binocul Vis Strabismus Q 16:43–44

19.Freedman SF, Rojas M, Toth CA (2002) Strabismus surgery for

large-angle cyclotorsion after macular translocation surgery. J AAPOS 6:154–162

20.Freedman SF, Seaber JH, Buckley EG, Enyedi LB, Toth CA (2000) Combined superior oblique muscle recession and inferior oblique muscle advancement and transposition for cyclotorsion associated with macular translocation surgery. J AAPOS 4:75–83

Surgery

on the Superior Oblique Tendon

12

Surgical procedures involving the superior oblique tendon are among the most intricate surgical procedures performed by the strabismus surgeon. Both the complex functions of the superior oblique muscle and its complex anatomical configuration make surgery on the superior oblique tendon unforgiving when proper indications and techniques are not carefully followed [1, 2]. Postoperative problems are often difficult to satisfactorily remedy. However, with careful consideration of the indications for surgery as well as meticulous detail to surgical technique, the results of surgery can be very satisfying.

The functions of the superior oblique muscle/tendon can be enhanced or reduced. The broad insertion of the superior oblique tendon into the sclera, as well as the anatomy of the insertion relative to the equator of the globe and the functional origin of the muscle in the superonasal aspect of the orbit result in the ability to alter specific functions of the superior oblique muscle/tendon by manipulation of different portions of the superior oblique tendon and its insertion. The anterior fibers of the superior oblique tendon, which course temporally from the superonasal aspect of the orbit, are anterior to the equator of the globe. They are thought to be primarily responsible for incycloduction of the globe (Chap. 2). The posterior fibers course posterior to the equator and are primarily responsible for depression and abduction. Because of its unique anatomy and surgery, physiology can be used to selectively weaken or strengthened a specific function(s) of the superior oblique muscle.

12.1Forced Traction Testing

of the Superior Oblique Tendon

Both forced traction testing and exaggerated forced traction testing are a useful adjunct during surgery on the superior oblique tendon (>Fig. 12.1). It can be very useful in identifying a lax superior oblique tendon, which commonly occurs in congenital superior oblique palsies [3–5] and the finding of a very lax superior oblique tendon may prompt the surgeon to consider a tucking procedure. Saunders and Tomlison [6] and Saunders [7] reported that, in order to avoid producing a large Brown syndrome after a superior oblique tendon tucking procedure, the surgeon should perform a traction test to help titrate the size of the tuck. Exaggerated forced traction testing of the superior oblique tendon is reviewed in detail in Chap. 8.

Chapter

12

Fig. 12.1. Traction testing to measure laxity or tightness of the superior oblique tendon. Surgeon’s view

12.2Superior-Oblique- Strengthening Procedures

Superior-oblique-strengthening procedures can be performed on the anterior portion of the tendon or on the full width of the tendon through tucking procedures. Tucking of the full width of the tendon tightens both the anterior and posterior tendon fibers and will therefore increase the impact of all three functions of the superior oblique muscle including incycloduction, depression, and abduction. Tucking of only the anterior fibers of the tendon selectively increases the incycloduction function of the superior oblique muscle and is used when excyclotorsion is the primary problem.

12.2.1Technique of Superior Oblique Tucking Procedure

A tuck of the superior oblique tendon is designed to enhance all three functions of the superior oblique muscle. It may be performed for the treatment of superior oblique palsy as an isolated procedure or be combined with a weakening procedure of another cyclovertical muscle such as the ipsilateral inferior oblique, ipsilateral superior rectus or contralateral in-

ferior rectus muscle. Following a tuck of the superior oblique tendon, some degree of iatrogenic limitation of elevation in adduction (referred to loosely as Brown syndrome) frequently occurs [8] and is usually required to achieve surgical success. Brown syndrome is less likely to occur when a superior oblique tuck is performed alone than when done in conjunction with a weakening procedure of the ipsilateral inferior oblique muscle [9]. The severity of the induced Brown syndrome can be minimized in two ways. A tucking procedure of the superior oblique tendon on the nasal side of the superior rectus muscle will generally produce a more significant restriction, and therefore tucking procedures are more commonly performed on the temporal aspect of the tendon near the insertion of the tendon into the sclera. Second, prior to tying permanent knots in the suture used to perform the tuck, traction testing can be performed to evaluate the tightness of the tucked tendon. If the tendon is found to be too tight, the tuck can be reduced accordingly. While we have found that many patients will demonstrate some degree of Browns syndrome after a superior oblique tuck, few are bothered by it. The exchange of single vision in side gaze, down gaze and relief of torticollis for a minimal degree of diplopia in adduction and elevation is acceptable to most patients. We have frequently noted that failure to produce some degree of restriction to elevation in adduction often, if not usually, results in undercorrection of the deviation.

Chapter 12

12.2.1.1Identifying the Superior Oblique Tendon

The superior rectus muscle is isolated using either a limbal or fornix approach (usually a fornix approach). Following isolation of the superior rectus muscle, a small muscle hook is used to retract the conjunctiva and Tenon’s fascia posteriorly along the lateral edge of the superior rectus muscle (>Fig. 12.2a). A small amount of dissection of the epimuscular fascia above the superior rectus muscle may facilitate exposure. A retractor can be placed in the posterior aspect of the incision to improve exposure of the temporal border of the superior rectus muscle as well as the superior oblique tendon. The insertional fibers of the superior oblique tendon can usually be easily identified traveling underneath the superior rectus muscle and fanning out to insert into the sclera posteriorly on the temporal side of the superior rectus muscle (>Fig. 12.2b).

12.2.1.2Isolation of the Superior Oblique Tendon

A small hook is placed on the sclera adjacent to the temporal border of the superior rectus muscle and anterior to the superior oblique tendon. The small hook is moved posteriorly as it is held against the sclera. It is then turned superiorly and with-

drawn anteriorly, resulting in isolation of the superior oblique tendon (>Fig. 12.3). A vortex vein is usually visible near the insertion of the tendon into the sclera and provides a good landmark. The small hook can be exchanged for a larger hook that will more securely maintain control of the tendon. Attachments between the superior oblique tendon and superior rectus muscle can be bluntly dissected if needed.

12.2.1.3Tucking of the Superior Oblique Tendon

The tendon is engaged on a tendon tucker and the desired size of the tuck dialed into the tucker (>Fig. 12.4a). The amount of tuck that is being performed can be read from the calibration markings on the tucking device. The calibration markings represent the length of each arm of the tuck. Therefore, the total tuck represents twice the amount indicated by the calibration marks. We generally report a tuck as follows so that it is clear to us later what we have done. If a 10-mm tuck has been performed (calibration marking 5 mm), we will denote this as a tuck of 5 + 5= 10. The size of the tuck required is dictated by the magnitude of the hypertropia in the primary position and by the degree of tendon laxity. Many cases of congenital superior oblique palsy demonstrate significant tendon laxity [3, 4] and require large tucks. In contrast, acquired palsies generally require only small tucks. We initially titrate the tuck to include

Fig. 12.3a,b. Isolating the superior oblique tendon. a A small hook is drawn anteriorly as it is held against the sclera posterior to the superior oblique tendon, resulting in isolation of the superior oblique tendon. b The small hook is exchanged for a larger hook

Fig. 12.4a–d. Tucking the superior oblique tendon with a tucking device. a The tendon is engaged on a tendon tucker and the desired size of the tuck dialed into the tucker. b A nonabsorbable suture is passed through the tendon to plicate the base of the tuck. c The base of the

tucked tendon should be examined to ensure that the knot is tight. d The tucked portion of the tendon can then be sutured to the sclera, if desired

the amount of tendon necessary to bring the base of the tuck close to the surface of the globe while placing mild anterior traction on the tendon.

A nonabsorbable suture is passed through the mid portion of the tendon inferior to the tucking device to plicate the base of the tuck (>Fig. 12.4b). We prefer the use of a 5-0 or 6-0 Mersilene suture. The suture can be tied temporarily or permanently depending on whether the surgeon will perform traction testing to assess the tightness of the tucked tuck. After completing the tuck and tying a permanent knot in the suture, the base of the tucked tendon should be examined to ensure that the knot is tight (>Fig. 12.4c). The tucked portion of the tendon can then be sutured to the sclera (>Fig. 12.4d) or simply allowed to retract back into the episcleral space.

If a tendon tucker is not available, the tendon can be folded on itself and a hemostat can be placed across the folded tendon at its base, followed by placement of a suture to plicate the tendon (>Fig. 12.5).

12.2.2Technique for the Fells Modification of the Harada-Ito Procedure

The Fells modification of the Harada-Ito procedure is used to correct excyclotorsion, most often in the setting of a bilateral superior oblique palsy with minimal vertical deviation in the primary position [10, 11]. The procedure involves advancement of the anterior portion of the superior oblique tendon. These fibers run relatively parallel with the equator of the globe and are primarily responsible for incycloduction of the globe.

After isolation of the superior oblique tendon on the temporal side of the superior rectus muscle, two small muscle hooks are used to divide the superior oblique tendon longitudinally extending from its insertion into the sclera for ap-

Fig. 12.5. Tucking the superior oblique tendon without using a tucking device

Fig. 12.6a,b. Fells modification of the Harada-Ito procedure. a The superior oblique tendon is split longitudinally, separating the anterior 25% of the tendon from the remainder of the tendon and an absorbable suture is secured in the anterior tendon fibers, which are then

detached from the sclera. b The detached portion of the tendon is sutured to the sclera 8 mm posterior and 2 mm superior to the superior edge of the lateral rectus muscle insertion

proximately 8–10 mm proximally. The anterior 25% of the tendon fibers are separated from the remainder of the tendon (>Fig. 12.6a). An absorbable suture is secured in the anterior tendon fibers, which are then detached from the sclera at the insertion (>Fig. 12.6a). The detached portion of the tendon is then advanced temporally and sutured to the sclera 8 mm posterior and 2 mm superior to the superior edge of the lateral rectus muscle insertion (>Fig. 12.6b). Passive incycloduction of the globe is usually obvious when the tendon is advanced (>Fig. 12.7).

12.2.2.1 Using Adjustable Sutures

If the potential to adjust the final position of the new tendon insertion is desired, the suture can be tied in a temporary knot [12]. After the desired alignment has been achieved through postoperative adjustment, a permanent knot is tied and the sutures cut (>Fig. 12.8). We often prefer intraoperative adjustment. Intraoperative adjustment is facilitated by viewing the fundus intraoperatively prior to beginning surgery, making

Fig. 12.10a,b. Classic Harada-Ito procedure. A 5-0 Mersilene doublearmed suture is passed around the anterior portion of the superior oblique tendon. The needles are passed 8 mm posterior to the inser-

note of the degree of objective retinal torsion based upon the optic nerve–fovea relationship. In a normal eye, a horizontal line drawn from the fovea intersects with the lower half of the disc (>Fig. 12.9). The position of the new insertion of the anterior fibers of the superior oblique tendon is adjusted until a normal optic nerve–fovea relationship is established.

12.2.3Technique for the Classic Harada-Ito Procedure

The classic Harada-Ito procedure has the advantage of being more easily reversed than the Fells modification of this procedure. The anterior portion of the tendon is isolated as described for the Fells modification. A 5-0 Mersilene double-armed suture is passed around the anterior portion of the tendon. The needles are then passed 8 mm posterior to the insertion site of the lateral rectus muscle at its superior border. The suture is pulled forward bringing the anterior portion of the tendon toward the lateral rectus (>Fig. 12.10).

Fig. 12.9a,b. Intraoperative adjustment of Harada-Ito procedure based on degree of objective retinal torsion. a Indirect ophthalmoscope schematic of the fundus demonstrating the relationship of the fovea and optic nerve in an eye with excyclotorsion. b Normal relationship reestablished

tion site of the lateral rectus at its superior border. The suture is pulled forward bringing the anterior portion of the tendon toward the lateral rectus muscle

12.3Superior-Oblique- Weakening Procedures

Indications for weakening procedures of the superior oblique muscle include treatment of superior oblique overaction, A-pattern strabismus, Brown syndrome, and incyclotorsion. Though the superior oblique muscle is a tertiary abductor (Chap. 2), the primary position horizontal effect of a weakening procedure on the superior oblique is considered to be negligible [13–15].

Techniques to weaken the superior oblique include both graded and nongraded procedures. Graded procedures include silicone expander insertion and recession of the superior oblique tendon. Nongraded techniques include tenotomy and tenectomy. Posterior tenectomy and Z-splitting of the superior oblique tendon combines some degree of both graded and nongraded weakening procedures. Z-splitting of the tendon is prone to development of scarring of the tendon to the superior rectus muscle and sclera which may result in unexpected alignment issues after surgery. Because of this risk and the availabil-

Fig. 12.11a–e. Superior oblique nasal tenotomy and tenectomy. a Exposure of the nasal intermuscular septum. b Visualization of the superior oblique tendon, c followed by a small incision through Tenon’s

fascia directly over the tendon. d The tendon is then isolated on two small muscle hooks and e transected (tenotomy), or a portion of the tendon is excised (tenectomy)