Anterior segment ischemia after strabismus surgery in a child

Risk of Anterior Segment Ischemia Following Simultaneous Three Rectus Muscle Surgery: Results from a Single Tertiary Care Centre

PURPOSE

The aim of the study was to determine the risk of anterior segment ischemia (ASI) after simultaneous three rectus muscle surgery.

METHODS

A retrospective cohort study was conducted. All patients who underwent simultaneous three rectus muscle surgery from January 2003 to December 2014 were included. Medical records were reviewed for signs of acute ASI in the postoperative period or presence of any late sequelae. Those patients who had pre-existing corneal pathology obscuring visualisation of anterior chamber and iris were excluded.

RESULTS

A total of 87 patients (54 males and 33 females) were included in the analysis. The mean age at the time of surgery was 22.5 ± 12.9 years (range 3.5 to 69.5 years). The common indications for surgery were monocular elevation deficit, sensory strabismus and third and sixth cranial nerve palsies. Mild form of ASI was seen in two patients, with no systemic or local illness, aged 30 and 9 years respectively. Both the patients underwent surgery on two vertical rectus muscle and one horizontal rectus muscle via the fornix approach. ASI resolved with topical steroids within two weeks in both the patients.

CONCLUSIONS

The risk of anterior segment ischemia after uncomplicated simultaneous three rectus muscle surgery was found to be 2.3% (95% CI = 0.3 to 8.1). It may occur in otherwise healthy young patients and even after fornix approach surgery.

Long-term therapeutic outcome of ophthalmic complications following endoscopic sinus surgery

Ophthalmic complications associated with endoscopic sinus surgery (ESS) are quite rare. There is a paucity of reliable data and limited experience on the clinical findings and treatments of these injuries. Our study here is to characterize the types of orbital injury following ESS, in particular extraocular muscle injury, and to evaluate the long-term therapeutic outcomes as compiled from a relatively large sample of Chinese patients.A series of 27 patients (21 males and 6 females; mean age = 42.6 years, ranges: 10-60 years) were retrospectively reviewed. The mean duration of orbital complication was 6.6 months (ranges: 1 day to 24 months). The right eye was affected in 19 patients and the left in 8 patients. All patients had various extraocular muscle dysfunction, including contusion, oculomotor nerve damage, muscle entrapment, muscle transection, and muscle destruction. All patients subjected to strabismus surgery showed an obvious reduction in deviation. Three patients achieved orthophoria without any surgery during the period of observation. All patients displayed mild to complicated orbital hemorrhage that often disappeared within 2 weeks. Optic nerve injury occurred in 29.6% of patients and vision damage in these patients was often irreversible.All patients with ophthalmic complications after ESS had strabismus and extraocular muscle dysfunction. Timing and type of strabismus surgery performed depended on the severity and number of muscles involved as well as the type of injury. This surgery is less effective in cases of restriction factor adhesion and/or entrapment as compared to that of patients with other types of strabismus. Orbital hemorrhages were usually resolved spontaneously, but optic nerve injury was mostly irreversible.

Natural course of anterior segment ischemia after disinsertion of extraocular rectus muscles in an animal model

PURPOSE

To compare the frequency and severity of anterior segment ischemia (ASI) after disinsertion of extraocular rectus muscles in a rabbit eye model.

METHODS

The rectus muscles of eyes of 84 rabbits were removed. In 42 rabbits one eye underwent three-muscle surgery, whereas the fellow eye underwent two-muscle surgery. In the other 42 rabbits, one eye underwent three-muscle surgery and the fellow eye four-muscle surgery. The surgery included disinsertion together with extirpation of the anterior 10 mm of the muscle. Each eye was examined daily to detect the presence of ASI. Anti-inflammatory eyedrops were not used in any subject. The severity of inflammation and time to complete resolution of inflammatory signs were documented. After inflammation resolved, both eyes of each rabbit were enucleated and studied by a pathologist.

RESULTS

The incidence of ASI was 9.5% in the two-muscle group, 31% in the three-muscle group, and 50% in the four-muscle group (P =0.001). ASI eyes all developed signs on the first postoperative day. Inflammation resolved in 4-38 days. The incidence of ASI increased significantly with the number of muscles operated on. Permanent complications were rare and histopathology results were normal in most cases.

CONCLUSIONS

Inflammation resolved spontaneously in all involved eyes without intervention and only minor clinical or pathologic changes were noted. One eye, however, developed severe sequela but was still preserved. The severity of ASI was directly correlated to the number of operated rectus muscles. Our findings suggest a self-limited nature of ASI in this rabbit model.

Vertical rectus muscles transposition in large exotropia with medial rectus muscle transection following endoscopic sinus surgery

Purpose

To evaluate the effect of transposition procedures on the vertical rectus muscle (VRM) in the patients who underwent a medial rectus muscle (MR) transection after endoscopic sinus surgery (ESS).

Methods

In 4 patients with exotropia (XT) and a lack of adduction after ESS, orbital CT or MRI revealed a complete transection of the midportion of the MR. Full-tendon VRM transposition was performed within 3 months after injury (early surgery) in 2 patients with 40Δ XT. Two patients with 70Δ and 85Δ XT underwent an X-type augmented Hümmelsheim procedure, which involved pulling each half-tendon and crossing it through the undersurface of the severed MR to the other end of the MR insertion, concurrently with an ipsilateral lateral rectus (LR) recession 11 months and 36 months after ESS, respectively. The adduction deficits were divided into -1 through to -8. The patients were followed up for more than than 1.5 years.

Results

Postoperatively, 3 patients showed orthophoria and no diplopia in the primary position. The adduction deficits improved to -3.5 or -4. One patient who underwent an X-type augmented Hümmelsheim procedure showed a residual XT of 25Δ.

Conclusions

VRM transposition is effective in correcting a large XT secondary to a MR transection after ESS. When a longstanding large-angle XT with severe contracture of the ipsilateral LR and massive scarring of the adjacent tissues is present, the X-type augmented Hümmelsheim procedure coupled with an ipsilateral LR recession had an augmenting effect.

Investigation of Hemodynamic Changes in the Ophthalmic Artery using Color Doppler Imaging after Strabismus Surgery

PURPOSE

We investigated hemodynamic changes in the ophthalmic artery (OA) using color Doppler imaging (CDI) after two horizontal rectus muscles surgery.

METHODS

Eyes of the surgical group (n=18) underwent surgery on two horizontal rectus muscles, and the control group was the contralateral eyes. CDI of the OA was performed before operation and on postoperative days (POD) 1, 7 and 30. Peak systolic (Vmax), end diastolic (Vmin), and mean (Vmean) blood flow velocities were measured, and resistivity index (RI) and pulsatility index (PI) were calculated.

RESULTS

Vmax, Vmin and Vmean were significantly higher, and RI and PI were significantly lower in the surgical group than in the control group on POD 1 (p<0.05). In the surgical group, Vmax, Vmin and Vmean were significantly higher, and RI and PI were significantly lower, on POD 1 than those measured on other days (p<0.05).

CONCLUSIONS

We showed that surgery on the two horizontal rectus muscles increased OA blood flow during the early postoperative period.

Investigation of hemodynamic changes after strabismus surgery using color Doppler imaging

PURPOSE

To investigate hemodynamic changes after strabismus surgery using color Doppler imaging (CDI).

METHOD

Group 1 patients (n = 13) underwent surgery on a single horizontal rectus muscle, and group 2 (n = 13) underwent surgery on both horizontal rectus muscles. Subjects with no systemic or ophthalmologic disorders were selected as controls (n = 16). In group 1 and group 2, CDI of the ophthalmic artery (OA), the central retinal artery (CRA), and the nasal and temporal posterior ciliary arteries (PCAs) was performed before surgical correction and on postoperative days 1 and 7. For each vessel, peak systolic (V(max)), end diastolic (V(min)), and mean (V(mean)) blood flow velocities were measured, in addition to the resistivity index (RI) and pulsatility index (PI).

RESULTS

V(max) in the OA on postoperative day 1 was higher in group 2 than in group 1 (P =.004). V(min) in the OA on postoperative day 1 was significantly higher in group 2 than in the controls (P =.001) and group 1 (P =.001). For group 2, comparison of the OA preoperative findings to the findings on postoperative day 1 showed that V(min) (P =.003) and V(mean) (P =.02) increased significantly, and the RI (P =.01) and PI (P =.006) decreased significantly. These significant differences were not observed on day 7 (P >.05).

CONCLUSION

Surgery on both horizontal rectus muscles in an eye causes hemodynamic changes in the OA in the early postoperative period.

Anterior segment ischemia after surgery on 2 vertical rectus muscles augmented with lateral fixation sutures

Anterior segment ischemia is a rare but potentially serious complication of strabismus surgery. Anterior ischemia typically occurs after surgery on 3 or 4 rectus muscles. Advanced age, dysthyroid ophthalmopathy, and a history of previous strabismus surgery are known risk factors for this complication. This report reviews the case of a healthy 50-year-old patient who developed anterior segment ischemia after surgery on 2 rectus muscles.

Evaluation of hemodynamic changes in the ophthalmic artery with color Doppler ultrasonography after strabismus surgery

PURPOSE

To investigate the blood flow changes in ophthalmic artery with color Doppler ultrasonography after strabismus surgery.

METHODS

Twenty eyes of 19 patients who underwent recession or resection surgery on two horizontal rectus muscles in 1 eye were examined using color Doppler ultrasonography preoperatively and 1 week and 1 month postoperatively. Measurements from both eyes of 16 age- and sex-matched normal subjects served as control data. The systolic maximum velocity, mean velocity, end-diastolic velocity, pulsatility index, and resistance index of the ophthalmic artery were determined. The Mann-Whitney U test was performed for comparison of the control and study group preoperatively for any hemodynamic parameter. Statistical comparison of the preoperative and postoperative measures in the study group was performed with Friedman's two-way analysis of variance.

RESULTS

No difference (P>.05) was observed preoperatively between the study and control groups for any hemodynamic parameter in the ophthalmic artery. Although the ophthalmic artery showed a slight increase in systolic maximum velocity 1 month postoperatively, there were no statistically significant differences (P>.05) in velocities or resistance in the ophthalmic artery at any interval.

CONCLUSION

Two horizontal rectus muscle operations in a previously unoperated eye do not cause significant hemodynamic changes in the ophthalmic artery. However, further studies are needed to obtain more information about the effect of multiple vertical rectus muscle operations on the blood flow parameters of the ophthalmic artery.

Anterior segment ischemia after the Jensen procedure in a 10-year-old patient

PURPOSE/METHODS

We recently encountered anterior segment ischemia in a young healthy girl with traumatic abducens nerve palsy after the Jensen procedure and ipsilateral recession of the medial rectus muscle. The patient was treated with topical dexamethasone and homatropine 2% and oral prednisone.

RESULTS/CONCLUSION

The patient's condition improved, and six weeks postoperatively, visual acuity was 20/20. As this complication of anterior segment ischemia is potentially serious and unpredictable, we think that an alternative surgical approach should be used when treating patients with muscle palsies.

Anterior segment ischemia after strabismus surgery

Surgery on the extraocular muscles of the eye is generally consisted a safe procedure which is associated with low morbidity and mortality. While infrequent, intra-operative complications occasionally occur. Tenotomy of multiple rectus muscles can result in interruption of the vascular supply to the anterior segment of the eye. Anterior segment ischemia (ASI) may result. This article reviews the complication of anterior segment ischemia as a result of strabismus surgery and its potential for producing permanent visual loss.

Preservation of anterior ciliary vessels during strabismus surgery: a nonmicroscopic technique

Preservation of anterior ciliary vessels (ACVs) during strabismus surgery using microscopic dissection techniques and the operating microscope has been previously described. We describe a technique using standard loupe magnification for vessel preservation, in 77 patients, ages 7 months to 69 years, who had surgery between January 1989 and September 1990. ACVs, with a small sheath of connective tissue, were dissected off the surface of the muscles and tendons using blunt and sharp dissection with Knapp iris hooks and Vannas scissors. Key elements of the dissection were sufficient separation of the vessel complex from the anterior tendon insertion and the use of blunt rather than sharp dissection. We successfully preserved 125 ACVs in 97 muscles. Ninety-five vessels were saved with 71 recessions, 14 with 13 resections, and 16 with adjustable sutures. The success rate of surgery was 85% in surgeries done either with or without anterior ciliary preservation. Vessel dissection time averaged 5 to 10 minutes per muscle. ACV preservation can be easily and successfully performed in routine strabismus cases. The procedure does not require the operating microscope and can be done under standard loupe (1.5 to 3.0 x) magnification. This procedure theoretically reduces the risk of anterior segment ischemia in situations where the patient is thought to be at significant risk for this complication.

Anterior segment vascular casting

Vascular corrosion casting provides a permanent three-dimensional record of the deeper vasculature of the anterior segment whereas fluorescein angiography allows clinical examination of superficial vessels. Morphological findings on scanning electron microscopy of vascular casts of the anterior segment in sheep are presented and compared with that of man by casting techniques. Sheep illustrate the basic mammalian anterior segment vascular architecture but lack anterior ciliary arteries which connect with the deeper collateral arterial circles. The casting technique is described and its use to answer comparative anatomical, pathological and clinical questions explained. These techniques are being applied to examine changes to the anterior ciliary arteries and the deeper vessels following strabismus surgery in an animal model. Scanning electron microscopy of vascular corrosion casts has given a new dimension to micro-vascular anatomy.

The effects of strabismus surgery on anterior segment circulation

Anterior segment circulation was assessed in 35 adults one day after squint surgery by clinical observation and low-dose fluorescein iris angiography. Seventeen patients had primary vertical rectus muscle surgery and all showed angiographic evidence of ischaemia. No ischaemia was found in the 15 patients who had secondary vertical rectus muscle surgery, or any horizontal rectus muscle surgery. The staged group had intermediate findings between the above two. Age, dysthyroid eye disease and type of conjunctival incision did not correlate with fluorescein iris angiographic sector-filling delay on the first post-operative day. The time taken for the sector with delay to fill becomes less during the first two post-operative weeks. Redistribution of iris filling persists, however. This data suggest that the safe interval before further muscle surgery can be done is shorter than has previously been assumed. Since the anterior ciliary arteries do not reform into canals the probable mechanism of redistribution of blood flow is from the long posterior ciliary arteries and increased capacity of the collateral circulation.

Preservation of the anterior ciliary vessels during extraocular muscle surgery

Conventional, full-tendon, rectus muscle surgery disrupts the anterior ciliary vessels. This may lead to anterior segment ischemia when the number of interrupted vessels is sufficient to significantly compromise anterior segment blood flow. Clinical observations and histologic studies provide new anatomic information concerning the course of the anterior ciliary vessels in the sub-Tenon's region. These studies demonstrate the feasibility of dissection and preservation of the anterior ciliary vessels during rectus muscle surgery. Dissection and preservation of 35 clinically apparent anterior ciliary vessel groups were attempted on 15 rectus muscles during strabismus surgery. The unplanned vessel destruction rate was 9.5%. Procedures included 12 recessions, 1 resection, and 2 full-tendon transpositions. The possible role of this procedure in the prevention of anterior segment ischemia is discussed.

Anterior segment ischemia after three rectus muscle surgery

Nine patients underwent simultaneous or staged detachment of the vertical and medial rectus muscles in the treatment of sixth nerve palsy or Duane's retraction syndrome. In five adult patients (34, 35, 41, 45, and 65 years of age), clinically significant anterior segment ischemia developed postoperatively. Known medical risk factors were present in only one case. With the exception of corectopia, there were no apparent sequelae and all involved eyes returned to preoperative visual acuity within 9 weeks of surgery. Anterior segment ischemia may be a frequent complication of strabismus surgery in adult patients when the superior, inferior, and medial rectus muscles are detached from the globe.