Minimally invasive strabismus surgery (MISS) for inferior obliquus recession

Single-snip paralimbal incision: A quick approach to rectus muscles

INTRODUCTION:

Less invasive and quicker surgeries have become common. We compared two conjunctival incisional approaches in strabismus, namely Follow standard paralimbal approach for (SPLA) and single-snip paralimbal (SSPLA).

MATERIALS AND METHODS:

Forty-four patients with horizontal strabismus qualifying for uniocular recession–resection surgeries were randomized to SPLA and SSPLA. SSPLA involved a single v-shaped incision, with the apex of the V near the limbus, and the limbs facing away: by pinching up the conjunctiva with a forceps and delivering the single snip with a spring scissors. We compared the postoperative grades of redness, congestion, chemosis, foreign body sensation, and drop intolerance at day 1, 2 weeks, and 6–8 weeks; scar visibility, as yes or no, at 6–8 weeks; success rates, considered to be within 10 prism diopters of orthophoria, at 6–8 weeks; and operation duration in minutes.

STATISTICAL ANALYSIS:

Statistical analysis was done using Mann–Whitney U-test, for inflammatory grades, Chi-square for proportions, and t-test for parametric measures. Statistical significance was set at P < 0.05.

RESULTS:

On postoperative day 1, congestion (P = 0.02), foreign-body sensation (P = 0.04), and total inflammatory score (P = 0.003) were statistically significantly favoring the SSPLA group. While at 2 weeks, only congestion (P = 0.02) was found to be significantly less in the SSPLA group. There were no significant differences in the proportions of scar visibility (5/22 in the SPLA vs. 3/22 in the SSPLA) and success rate: 20/22 vs. 18/22. The SSPLA was quicker on an average by 6 min (P < 0.001, 95% confidence interval: 3.2–8.7).

CONCLUSION:

Compared to the SPLA, the SSPLA is quicker and results in lesser inflammation in the immediate postoperative period.

Contributions to Progress in Ophthalmology from Switzerland: From the 16th to the 21st Century

There are numerous contributions to the development of ophthalmology from Switzerland, a country that holds a very special place in the history of medicine from the age of Paracelsus and Vesal to the current time. This review gives an overview over these contributions and the pioneers, among them Johann Friedrich Horner, Hans Goldmann, Jules Gonin, and Walter Rudolf Hess, one of only two ophthalmologists ever awarded the Nobel Prize for Medicine. A leading role in this evolution of modern ophthalmology has been played by physicians from Basel, home of Switzerland's oldest university.

Changes in conjunctival-scleral thickness after strabismus surgery measured with anterior segment optical coherence tomography

PURPOSE

To evaluate changes in conjunctival-scleral thickness following strabismus surgery with anterior segment optical coherence tomography (AS-OCT).

STUDY DESIGN

Prospective, observational, consecutive case series.

METHODS

Distances between the conjunctival epithelium and inner scleral wall were measured with AS-OCT before and 3-5 months after strabismus surgery. The measurements were performed at 1.5 mm (limbus), 7.0 mm (insertion), and 8.0 mm (tendon) posterior to the scleral spur on the lateral rectus muscle (LR); and 1.5 mm (limbus), 4.0 mm (insertion), and 5.5 mm (tendon) posterior to the scleral spur on the medial rectus muscle (MR). Thirty-three extraocular muscles (20 LRs and 13 MRs) from 23 subjects were studied.

RESULTS

Thicknesses were significantly less at the insertion (0.95-0.78 mm; p < 0.001) and tendon (0.99-0.78 mm; p < 0.001) after LR recession and at the tendon (1.21-0.92 mm; p = 0.02) after MR recession. Thicknesses were significantly greater at the insertion (0.82-1.07 mm; p = 0.01) and tendon (0.95-1.28 mm; p = 0.01) after MR resection or plication and at the limbus, insertion, and tendon (0.75-0.90 mm, 0.94-1.19 mm, 1.03-1.28 mm, respectively; all p = 0.04) after LR resection or plication.

CONCLUSION

Conjunctival-scleral thicknesses showed various changes after recession and resection or plication. These findings may help detect previous surgical operations when conjunctival scarring and ciliary vessel changes are unclear.

A Review of Minimally Invasive Strabismus Surgery (MISS): Is This the Way Forward?

Minimally invasive surgery is rapidly becoming the norm in medicine, as it often leads to better outcomes and earlier rehabilitation. This article reviews the principles and different techniques employed to perform minimally invasive strabismus surgery (MISS). In these techniques, strabismus surgery is performed through keyhole openings, thus reducing the risk of postoperative corneal complications, minimizing postoperative discomfort, and better preserving muscle function. MISS can be used to perform all types of strabismus surgery, namely rectus muscle recessions, resections, plications, reoperations, retroequatorial myopexy, transpositions, oblique muscle recessions, or plications even in the presence of limited motility. Of note, ocular alignment outcomes with MISS versus more traditional techniques have not been compared in randomized trials. Consequently, more controlled evidence is still needed to better delineate the future role and value of MISS in clinical management.

Outcomes of minimally invasive strabismus surgery for horizontal deviation

OBJECTIVE

To study the outcomes of minimally invasive strabismus surgery (MISS) for treating horizontal deviation

METHOD

Case Series of the first 26 consecutive patients operated on using the MISS technique in our hospital from February 2010 to March 2014.

RESULTS

A total of 40 eyes were included: 26 patients (mean age: 7.7 years old ± 4.9); 34.61%: male. A total of 43 muscles were operated on: 20 medial, and 23 lateral recti; 28 recessions (range: 3-7.5mm), 6 resections (6-7 mm), and 9 plications (6.5-7.5 mm) were performed. No significant difference was found (P>0.05) for visual acuity at postoperative day 1, and 6 months after surgery. A mild hyperaemia was observed in 29.27%, moderate in 48.78%, and severe in 21.95% at postoperative day 1 and in 63.41%, 31.70% and 4.87%, respectively, at 4 days after surgery. The complications observed were 4 intraoperative conjunctival haemorrhages, 1 scleral perforation, and 2 Tenon's prolapses. A conversion from MISS to a fornix approach was necessary in 1 patient because of bad visualization. The operating time range decreased from 30 to 15 minutes.

CONCLUSIONS

The MISS technique has obtained good results in horizontal strabismus surgery. The conjunctival inflammation was mild in most of the cases at postoperative day 4. The visual acuity was stable during follow-up, and operating time decreased after a 4-year learning curve.

Minimally Invasive Strabismus Surgery (MISS) Compared with the Fornix Approach in Pediatric Horizontal Strabismus Surgery

OBJECTIVE

To compare minimally invasive strabismus surgery (MISS) with the fornix approach in horizontal strabismus operations.

PATIENTS AND METHODS

We performed a retrospective study of all patients aged ≤ 12 years who underwent symmetrical surgery of the medial or lateral recti over a 1-year period. MISS was performed in one eye, and fornix opening was performed in the contralateral. We compared pre- and postoperative visual acuity (VA), conjunctival hyperemia, swelling after surgery, and operating time. The techniques were performed by 2 surgeons after a 4-year training period.

RESULTS

The sample comprised 16 patients, with a mean age of 6.75 ± 3.02 years. The medial rectus was operated on in 9, the lateral rectus in 7 cases. Recession was performed in 14 muscles (mean dose, 5 mm) and plication in 2 (5.5 mm and 7 mm, respectively). MISS was performed in 12 right eyes and 4 left eyes. Preoperative VA was 0.77 in MISS and 0.80 in the control group. VA was 0.83 in MISS and 0.76 in the control group 1 day after surgery. No significant differences were found for conjunctival hyperemia between the MISS and fornix groups 1 day or 1 week after surgery. Nevertheless, moderate/severe conjunctival hyperemia was less frequent in the MISS group (31.3% versus 62.5%). No significant differences were found for operating time (14.43 minutes [MISS] vs 12.37 minutes [control]).

CONCLUSION

The MISS technique was similar to the fornix approach in the early postoperative period with respect to VA, conjunctival inflammation, and operating time in pediatric horizontal strabismus surgery.

Review: minimally invasive strabismus surgery

This article reviews the principles and different techniques used to perform minimally invasive strabismus surgery (MISS). This term is used for strabismus surgeries minimizing tissue disruption. Muscles are not accessed through one large opening, but using several keyhole openings placed where needed for the surgical steps. If necessary, tunnels are created between cuts, which will allow performing additional surgical steps. To keep the keyhole openings small, transconjunctival suturing techniques are used. The cuts are always placed as far away from the limbus as feasible. This will reduce the risk for postoperative corneal complications and it will ensure that all cuts will be covered by the eyelids, minimizing postoperative visibility of surgery and patient discomfort. Benefits from minimizing anatomical disruption between the muscle and the surrounding tissue are a better preservation of muscle function, less swelling, and pain, and more ease to perform reoperations. MISS openings allow to perform all types of strabismus surgeries, namely rectus muscle recessions, resections, plications, reoperations, retroequatorial myopexias, transpositions, oblique muscle recessions, or plications, and adjustable sutures, even in the presence of restricted motility.

Intraoperative conversion rate to a large, limbal opening in minimally invasive strabismus surgery (MISS)

BACKGROUND

To evaluate which factors predispose to an intraoperative conversion to the usual limbal approach in minimally invasive strabismus surgery (MISS).

METHODS

This study included 451 consecutive patients operated on by one surgeon at Kantonsspital St Gallen, Switzerland, with minimally invasive rectus muscle surgery between February 2003 and December 2007. We evaluated the intraoperative conversion rate to the usual limbal approach over time, and performed a retrospective determination of date of surgery, age of patient, motility of the eye, primary or revision surgery, and the type and dose of surgery in 982 consecutive rectus muscle procedures.

RESULTS

In 3.6% (35/982) of MISS procedures, an intraoperative conversion to a large, limbal approach was necessary. The overall conversion rate decreased over time, from 8.4% in 2003 to 0.4% in 2007. The multivariate regression analysis showed a significant negative influence between the date of surgery and the conversion rate (p < 0.005). Muscle resections were associated with a higher conversion rate (p < 0.001). The other evaluated factors had no significant influence on an intraoperative enlargement of the conjunctival opening.

CONCLUSIONS

This study confirms the reliability of the new MISS technique, and shows a low conversion rate to the usual limbal approach. The conversion rate decreased over time with increasing surgical experience. Muscle resections were associated with a higher conversion rate, while the age of the patient, the motility of the eye, revision surgery and the dose of surgery had no significant influence on an intraoperative conversion.

A new transconjunctival muscle reinsertion technique for minimally invasive strabismus surgery

PURPOSE

To describe a novel, minimally invasive strabismus surgery (MISS) technique for horizontal rectus muscle recessions, plications, and advancements.

METHODS

Subjects for this prospective study were the first 20 consecutive patients who underwent unilateral horizontal rectus muscle surgery with a transconjunctival suturing (TRASU) technique for primary muscle displacements of 4.5 mm or greater or for repeat muscle displacements of 3.0 mm or greater.

RESULTS

The TRASU technique was associated with no increase in complication rate and was accomplished through a conjunctival approach with an incision that was smaller by 31% ± 11% compared to incisions for previously described MISS approaches. Of the 19 patients (20 eyes) returning for follow-up, 11 (55%) had minimal redness as the only grossly visible sign of surgery on the first postoperative day. By 6 months postoperatively, visual acuity and refractive error were not significantly different from preoperative values (P > .10 for each).

CONCLUSION

The TRASU technique is safe and can be accomplished through a conjunctival incision that averages two-thirds the size of incisions for previously reported MISS techniques.

Combined horizontal rectus muscle minimally invasive strabismus surgery for exotropia

OBJECTIVE

To evaluate combined horizontal rectus muscle minimally invasive strabismus surgery (MISS) for exotropia.

DESIGN

Case series.

PARTICIPANTS

Fifty-two consecutive exotropic patients operated on by 1 surgeon with MISS combined unilateral lateral rectus muscle recession and medial rectus muscle plication.

METHODS

Alignment, binocular single vision, conjunctival injection and swelling, and complications during the first 6 postoperative months were recorded prospectively. Conjunctival swelling and injection on the first postoperative day were scored retrospectively and compared with historic controls operated on with combined recession-plication or recession-resection using a limbal approach.

RESULTS

Conjunctival swelling and injection were mainly mild on the first postoperative day and less pronounced than after surgery with a limbal approach (comparison of swelling and injection for MISS vs limbal opening recession-plication p < 0.001 and for MISS vs limbal opening recession-resection p < 0.001). A conversion to a limbal approach was necessary in 3/104 (3%, 95% CI 1%-7%) of all muscles. No scleral perforation or other serious complication was observed, and no patient needed a repeat operation within 6 months (0/49, 0%, 95% CI 0%-6%).

CONCLUSIONS

This study demonstrates that small-incision, minimal dissection combined recession-plication surgery induces less conjunctival swelling and injection compared with the usual limbal approach.

Minimally invasive strabismus surgery for rectus muscle posterior fixation

AIMS

To present a novel, minimally invasive strabismus surgery (MISS) technique for rectus muscle posterior fixation.

METHODS

This study reports the results of 32 consecutive MISS rectus muscle posterior fixation surgeries performed on 19 patients by applying only two small L-shaped openings where the two retroequatorial scleromuscular sutures were placed.

RESULTS

On the first postoperative day, in primary position, redness was hardly visible in 16 eyes (50%) and only moderate redness was visible in 6 eyes (19%). No serious complication occurred. Preoperative visual acuity and refraction remained unchanged at 6 months (p > 0.1). The preoperative convergence excess (n = 13) decreased from 10.3 +/- 4.1 to 5.2 +/- 4.0 degrees at 6 months (p < 0.005). In all patients operated on for gaze incomitance (n = 6) improvement was achieved at 6 months.

CONCLUSIONS

This study shows that keyhole minimal-dissection rectus muscle posterior fixation surgery is feasible and effective to improve ocular alignment. The MISS technique seems to be superior in the direct postoperative period since only minimal conjunctival swelling and no corneal complications were observed.