The art of tackling strabismus skillfully by sparing vessels

Background: Detaching a rectus muscle irreparably destroys its ciliary artery circulation which also supplies the anterior segment of the eye. Purpose: To educate strabismus surgeons about a method of detaching a muscle without compromising anterior segment circulation. Synopsis: A limbal based conjunctival incision is made. The muscle is identified, separated from its attachments and secured with 6-0 Vicryl. The anterior ciliary vessel supplying it is isolated by making a small snip incision in the muscle capsule with delicate blunt dissection parallel to the anterior ciliary artery The muscle is detached from its original insertion. The muscle is tied to sclera at the intended point of recession. The intact anterior ciliary artery, thus will continue to function, untouched. Highlights: We recommend pre-placing the sutures in the muscle and also in the sclera at the point of reattachment to avoid possible stretching and breaking of anterior ciliary vessels at the time of muscle detachment and also to dissect the artery free from muscle several millimeters more than the intended recession in order to spare the anterior ciliary circulation in strabismus surgery.

Research progress of anterior segment ischemia after extraocular muscle surgery / 国际眼科杂志(Guoji Yanke Zazhi)

@#Anterior segment ischemia(ASI)is a rare but serious complication after extraocular muscle surgery. Due to its complex clinical manifestations, it is easy to be misdiagnosed. If not treated in time, it may lead to blindness such as vision loss. This paper mainly reviews the concept, clinical manifestations, pathogenesis, risk factors, diagnosis and treatments of ASI after extraocular muscle surgery, so as to improve people's understanding of ASI and minimize or avoid the occurrence of ASI in clinical work.

Clinical observation of monocular rectus surgery for adult sensory exotropia / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To evaluate the effect of monocular rectus surgery for adult sensory exotropia. <p>METHODS: Totally 76 cases of adult sensory exotropia of degree -15^△ to -160^△(-68.36^△±30.77^△)examined through Krimsky method were included into this study. A total of 16 cases, 37 cases and 23 cases with different degrees of strabismus were treated separately with routine amount monocular lateral rectus recession, routine amount monocular medial rectus resection plus lateral rectus recession, and exceed constant amount monocular medial rectus resection plus lateral rectus recession. Follow-up was performed at 1d, 1wk, 1, 3 and 6mo after operation. The eye position, monocular movement, intraocular pressure(IOP), slit lamp, and fundus of these patients were examined. <p>RESULTS:After surgery, 67 cases(88%)were positive and 9 cases(12%)were undercorrection. The postoperative intraocular pressure of operative eye at 1wk was equal to preoperative(<i>P</i>=0.090), and IOP decreased to a valley value at 1mo(<i>P</i><0.01), there was no significant difference in intraocular pressure between 3mo and 1mo(<i>P</i>=0.092), and no significant difference in intraocular pressure between 6mo and 3mo(<i>P</i>=0.123). And 2 cases(3%)had inflammatory reaction induced by anterior segment ischemia at 1d and 1wk postoperative visits, and they recovered at 1mo follow-up visit; 4 cases(5%)experienced an external dysfunction at the 1, 3 and 6mo follow-up. <p>CONCLUSION:Monocular rectus surgery has a good therapeutic effect on adult patients with sensory exotropia; the decrease in intraocular pressure secondary to the detached rectus is worth the attention of the surgeon; the incidence of complications after detaching monocular of two rectus muscles is comparable low. Exceed constant amount rectus strabismus surgery for sensory exotropia may result in limited function of postoperative ocular hyperextension.

Anterior segment ischemia following Hummelsheim procedure in a case of sixth nerve palsy.

A, 46‑year‑old Indian male, known hypertensive presented with left esotropia of 25 prism diopters (PD) after head injury in a roadside accident 9 months back. The deviation was constant in nature and was associated with complaints of diplopia in left lateral gaze. Traumatic sixth nerve palsy was diagnosed. The patient underwent left medial rectus recession of 5 mm and a split‑tendon transposition of the left superior and inferior recti to the lateral rectus insertion (Hummelsheim procedure). On the first postoperative day, the patient developed corneal edema and anterior chamber reaction of flare 2+ and cells 2+. The pupil was semi‑dilated and was sluggishly reacting to light. Anterior segment ischemia was diagnosed, which was managed with topical and systemic steroids.

A Case of Nishida Muscle Transposition Procedure for Abducens Palsy

PURPOSE: Herein we report a successful Nishida muscle transposition procedure (modified Jensen procedure) with right medial rectus recession for treating a right abducens palsy patient. CASE SUMMARY: A 63-year-old male presented with a 30-year history of esotropia due to traumatic abducens palsy in his right eye. At initial examination, right eye visual acuity was 0.9 and intraocular pressure was 11 mm Hg. Ocular movement of the right eye was restricted in the lateral direction and prism cover-uncover test revealed 75 prism diopter right esotropia. For 2 years, the patient was treated as normal tension glaucoma and used his right eye as the dominant eye by turning his head due to glaucomatous field defect in the left eye. We performed 8.0 mm medial rectus recession and Nishida muscle transposition procedure in the right eye and inserted a suture through the temporal margin of each vertical rectus muscle. One week after surgery, the right eye maintained relatively straight alignment and prism cover-uncover test showed 20 prism diopter residual esotropia in the left eye. CONCLUSIONS: The Nishida muscle transposition is a simple procedure and prevents postoperative risk of anterior segment ischemia without the occurrence of tenotomy and muscle splitting. We report a successful Nishida muscle transposition procedure in a patient with chronic abducens palsy.

The Evaluation of Anterior Segment Ischemia in Pigmented Rabbits Using Indocyanine Green (ICG) Iris Angiography

To evaluate the usefulness of indocyanine green (ICG) iris angiography in darkly pigmented iris and to investigate whether the anterior segment ischemia can be produced by tenotomies of two or more rectus muscles in rabbits, twenty one eyes of 21 pigmented rabbits wer divided into four groups according to the surgical procedures. Group I (2 eyes) underwent only conjunctival peritomy as a control. Group II (6 eyes), Group III (9 eyes), Group IV (4 eyes) underwent tenotomies of two, three and four rectus muscles, respectively. All these eyes underwent ICG iris angiography at pre-op, post-op 10 housrs, 3 days, 7 days and 14 days. In eight eyes of Group I and Group II, fluorescein iris angiography was taken simultaneously. The quality of fluorescein iris angiography was much lower in the pigmented iris and the interpretation was more difficult compared to ICG iris angiography. The peritomy (Group I) or tenotomies of two rectus muscles (Group II) produced no circulatory defect of the iris even after 10 hours postoperatively. After tenotomies of three rectus muscles (Group III) there were transient mild filling defects in superior or inferior sector of iris in 7 of 9 eyes. These defects lasted for 1 to 3 days. Tenotomies of four rectus muscles (Group IV) produced transient filling defects which lasted for 1 to 7 days. ICG iris angiography was suitable for the evaluation of anterior segment circulation in darkly pigmented iris, thus, it can be applied to the coriental brown iris. And in contrast to the previous concept that the rabbits iris arteries derive solely from the long posterior ciliary arteries, circulatory disturbance of iris, even though transient, could be produced by severance of rectus muscles.

Two Cases of Anterior Segment Ischemia After Strabismus Surgery

Anterior segment ischemia(ASI) may be caused by a detachment of the rectus muscles from the globe. The interruption of the anterior ciliary artery by the detachment of rectus muscles causes a subsequent hypoperfusion to the anterior segment. ASI occurs more easily after surgery on the vertical rectus or after detachments of two or more adjacent rectus muscles. We experienced two patients with ASI after performing muscle surgery on them for lateral rectus muscle palsy caused by a traffic accident. A 5-year-old-male developed keratitis and uveitis following a Hummelsheim operation in combination with a lateral rectus resection in his right eye. A 51-year-old female showed keratitis, uveitis and pupilary distortion after a Knapp procedure combined with a lateral rectus tucking in her right eye. Both patients recovered without any complications.

A Case of The Modified Jensen Procedure Saving Anterior Ciliary Arteries

For the 6th nerve paralysis, we use the procedure described by Jensen combined with a 6-7mm recession of the madial rectus muscle. But, anterior segment ischemia(ASI) is an occasional complication of this surgery in which over three rectus muscles are partially or completely detached, ligated. The authors performed this modified Jensen procedure to the patient of 6th nerve paralysis, in which anterior ciliary arteries of vertical rectus muscles were separated from the muscles under the operating microscope and then ligated muscles only. So, this modified procedure preserve the integrity of the anterior ciliary arteries in those portions of the vertical muscles not involved in the muscle union to avoid the danger of anterior segment ischemia.

Recession of 4 Rectus Muscles for Neovascular Glaucoma or Absolute Glaucoma

We have performed recession of all 4 rectus muscle in 8 eyes with neovascular or absolute glaucoma. The visual acuity of these eyes ranged fram no light perception to recognition of hand motion. As the purpose of surgery was to destroy all anterior ciliary arteries from the rectus muscles, after performing 2mm recessions on all 4 rectus muscles we applied cryotherapy on the oclera from he original rite to the mear insertion site. The cases were followed up for periods ranging from 3 to 19 months, with an average of 10.3 months. At the end of follow-up periods, we observed a statistically significant drop (p<0.05) in the intraocular pressure level, from the preoperative leveI of 49.8 +/- 7.9 mmHg (mean +/-SD) to 36.6 +/- 18.1 mmHg without any additional medical therapy. However, the decreases were not notable. In the treatment of neovascular glaucoma for absolute glaucoma, we have found that simultaneous disruption of all anterior ciliary arteries through anterior segment ischemia will not result in a satisfactory decrease in postoperative intraocular pressure.

A Study of the Effect of Botulinum Toxin A(Oculinum(R)) in the Case of Abducens Nerve Palsy

Seventeen cases of paralytic strabismus secondary to abducens nerve palsy were treated with an injection of Botulinum Toxin A(Oculinum(R)) into the medial rectus muscle under the electromyographic control. All 17 cases, including 3 cases of bilateral abducens palsy, were followed up for 6 months to 23 months after the initial injection, there were no systemic side effects. The etiologic factors follow up deviation angle, dosage and complications were analyzed In the Thirteen cases of Oculinum(R) injection in antagonistic medial rectus muscle, the mean correction of preinjection deviation was 48.7%; the four cases who underwent both Jensen's operation and Oculinum(R) injection obtained 64.6%. The most common complication was ptosis which developed in 15 cases(64.7%) with a dosage of 2.75 u or above. From this study. we concluded that Oculinum(R) chemodenervation was effective in the acute case of abducens palsy without the anterior segment ischemia and systemic side effects.

Effect of a modified rectus tuck on anterior ciliary artery perfusion

Strabismus surgery results in the permanent interruption of anterior ciliary blood flow, predisposing the eye to anterior segment ischemia (ASI). A primate model was used to assess the effectiveness of a new muscle-scleral tuck for preserving anterior ciliary artery circulation. The model consisted of removing 3 rectus muscles from both eyes of 2 rhesus monkeys, then performing a tuck on the inferior rectus (IR) right eye while leaving the left IR as a control. Four weeks later, a modified tuck was performed on the virgin left IR. Fluorescein iris angiograms of both eyes were obtained, and preoperative angiograms at 5-15 sec. showed normal 360 degrees perfusion. Postoperative follow-up angiograms showed segmental superior temporal filling defects and preservation of perfusion in the distribution of the IR. Comparison of fellow eyes tucked vs control IR showed no difference in the filling pattern in both monkeys. Comparison of the same eye before and after tuck also showed essentially the same filling pattern in all 4 eyes with preservation of inferior circulation. Our conclusion is that the modified tuck preserves the anterior ciliary blood flow and may be useful as a muscle-strengthening procedure in patients predisposed to developing ASI.