Vitrectomy for Perforating Eye Injuries From Shotgun Pellets D . Virgil Alfaro, M.D., V i n h T. Tran, M . D . , Todd Runyan, M.S., Lawrence P. C h o n g , M . D . , S t e p h e n J. Ryan, M . D . , a n d Peter E. Liggett, M . D .
Pars plana vitrectomy and scierai buckling were performed on 22 eyes of 19 patients for treatment of perforating eye injuries from shotgun pellets. We reviewed the intraoperative findings at the time of vitrectomy to determine what factors might influence final visual acuity. The presence of a total retinal detachment at vitrectomy portended a poor prognosis when compared with eyes without total retinal detachment, as only one of ten eyes with total retinal detachment obtained useful vision (P = .002). Preoperative separation of the posterior vitreous was associated with a favorable outcome when compared with the absence of posterior vitreous detachment (P = .035), as ten of 16 eyes with posterior vitreous detachment at the time of vitrectomy ultimately achieved functional vision. The locations of the exit wounds did not affect visual success in the overall series of patients. However, in the patients who achieved visual success, exit wounds outside the vascular arcades were more likely to be associated with final visual acuities of, or better than, 20/70 than were those within the arcades (P = .022). Other prognostic factors, such as the number of perforations and the use of cryotherapy, were also examined for their effects on final visual outcome. However, these factors did not appear to affect visual outcome statistically.
Accepted for publication March 16, 1992. From the Department of Ophthalmology, University of Southern California School of Medicine, the Doheny Eye Institute, and Los Angeles County-University of Southern California Medical Center, Los Angeles, Cali fornia. This study was supported in part by a Core Grant for Vision Research (EY03040) from the National Insti tutes of Health, Bethesda, Maryland. Reprint requests to Peter E. Liggett, M.D., Yale Univer sity School of Medicine, Yale University, 330 Cedar St., New Haven, CT 06510.
PERFORATING INJURIES OF THE EYE result from a missile entering the eye, penetrating the vitre ous cavity, traversing the posterior segment, and exiting the eye posteriorly. A large series of such eyes showed that eyes with perforating injuries have poor visual outcomes, 1 although more recent studies have suggested that vitrec tomy may help to salvage some of these eyes.2,3 Retinal injury, retinal detachment, and the status of the posterior vitreous are thought to influence the final outcome in patients with perforating injury involving the posterior seg ment. To assess those factors that might predict outcome, we reviewed the records of 19 consec utive patients who had sustained perforating eye injuries from shotgun pellets; we evaluated the intraoperative findings at the time of vitrec tomy to determine what factors might influence final visual acuity.
Patients and Methods We reviewed the records of 19 consecutive patients (22 eyes) who underwent pars plana vitrectomy and scierai buckling for perforating injuries of the eye sustained from shotgun pel lets from July 1986 through February 1990. One additional patient treated during this period was excluded from the study because he was lost to follow-up immediately after surgical procedures. Hospital records and operative notes provided patient age, initial visual acuity, perforation sites, elapsed time from injury to vitrectomy, presence of retinal detachment, presence of posterior vitreous detachment, lo cations of the exit wounds, anatomic result, and final visual acuity. All patients were followed up for six to 48 months. Eighteen of the 19 patients were male, and ages ranged from 17 to 40 years; all were either black or Hispanic and had been assaulted. All
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patients had visual acuity of light perception or hand motion at the time of initial examination. All patients underwent primary repair of the perforating injuries within 24 hours of the as sault. Corneal wounds were repaired before conjunctival peritomy. If prolapsed subconjunctival uvea, subconjunctival blood, or both, suggested a scierai perforation, the conjunctiva and Tenon's capsule were locally dissected away from the wound. Prolapsed vitreous was excised with a dry, cotton-tipped applicator and scissors. Scierai lacerations were repaired with 8-0 nylon suture. After repair of the cornea and anterior sclera, a 360-degree peritomy was performed and all four quadrants of the globe were inspected by using a Schepens retractor and a cotton-tipped applicator. Each of the lateral recti muscles was then isolated and re tracted to allow visualization underneath the muscle. If scierai perforation was seen at the insertion of the muscle, the muscle was de tached from the globe and then reinserted after repair. Posterior perforations were not repaired if retraction did not permit full visualization of the wound. In the period between primary repair and vitrectomy, the patients were examined with serial ultrasonography to assess the status of the retina and posterior vitreous. In most cases, vitrectomy was performed during the second or third week after trauma, although some pa tients chose to postpone surgical procedures. We used a dual-function aspiration cutting sys tem for vitrectomy. The lens was salvaged if possible, but pars plana lensectomy was per formed in cases of cataract or lens subluxation. A core vitrectomy was performed to remove media opacities, and the posterior hyaloid was stripped from the retinal surface when possible. Attempts were made to trim the vitreous base with the cutting instrument in conjunction with scierai indentation. Cortical vitreous was re moved from the posterior exit wounds up to the edges of incarcerated tissue. A broad scierai buckle (No. 287) with an overlying No. 240 band secured by a No. 70 sleeve was placed around each eye. Retinal breaks were treated with cryopexy or intraocular photocoagulation. Prolonged intraocular tamponade with sulfur hexafluoride (SF6) or perfluoropropane (C3F8) was used in 12 eyes; silicone oil was used in three eyes with severe intraocular disorganiza tion and total retinal detachment. We defined visual and anatomic successes according to the criteria of Ryan and Allen. 4 Vis ual success was defined as postoperative visual acuity of 5/200 or greater (by Snellen chart) if preoperative visual acuity were light percep
tion or hand motions. Anatomic success was defined as successful reconstruction of the globe but failure to meet the criteria for visual success. A (through-and-through) perforating eye in jury was defined as one in which a pellet en tered the eye by penetrating the cornea or anterior sclera, and exited the eye by perforat ing the sclera posteriorly, into the orbit. An eye with multiple perforations was defined as one with two or more perforations of the sclera. Fisher's exact (two-tailed) tests were per formed to test for association between the end points (visual success) and the following possi ble prognostic factors: retinal detachment, pos terior vitreous detachment, number of perfora tions, perforation within the vascular arcade, and the use of cryotherapy.
Results Vitrectomy was performed on 16 eyes be tween one and three weeks after injury. Vitrec tomy was performed on three eyes 23 days after injury and vitrectomy was performed in three eyes after more than one month from the time of trauma. Overall, visual success was achieved in 11 eyes, anatomic success was achieved in three eyes, and treatment failed in eight eyes. Final visual acuity fell within the range of 5/200 to 20/30. Final visual acuity of, or better than, 20/70 was achieved in six of the 11 eyes with visual success. In three eyes that were recon structed anatomically, visual acuity remained at hand motions and 2/200. Eight eyes could not be reconstructed, resulting in no light per ception. Seventeen eyes had one perforation. Of the five eyes that had multiple perforations, one eye had a pellet that penetrated the anterior sclera at one entry site and fragmented into two separate fragments, which then perforated the posterior eye wall at two separate exit wounds; three eyes had two perforations from two pel lets; and one had three perforations from three pellets. Of the 17 eyes with one perforation, ten were visual successes, two were anatomic suc cesses, and treatment failed in five. Of the five eyes with multiple perforations, one was a visual success, one was an anatomic success, and treatment failed in three. Thus, treatment failed in five of the 17 eyes (29%) with one perforation, whereas treatment failed in three of the five eyes (60%) with multiple perfora tions. Multiple perforations (from one or multi-
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pie pellets) appeared to be associated with worse outcome. However, such association did not achieve statistical significance (P = .31). Locations of the exit wounds with respect to the vascular arcades were also analyzed as a prognostic factor for visual outcome. Nine eyes had exit wounds within the vascular arcades and 11 eyes had exit wounds outside the ar cades. The locations of the exit wounds could not be determined from the operative notes on two eyes, which were therefore not included in this analysis. Five of the nine eyes with a perforation within the vascular arcades achieved visual success. Six of the 11 eyes with a perforation outside the arcades achieved visu al success. Thus, the location of the exit wound did not influence final visual acuity in the overall series. However, among the eyes that achieved visual success, visual acuities were better in those eyes that had exit wounds out side the vascular arcades (Fig. 1) as compared with eyes in which exit wounds were located within the vascular arcades (Fig. 2). When only outcomes of eyes that achieved visual success were analyzed, none of the five eyes with exit wounds within the vascular arcades had visual acuities of 20/70 or better, whereas all six eyes with exit wounds outside the vascular arcades achieved final visual acuities of 20/70 or better (P = .022). Ten eyes had total retinal detachment at the time of vitrectomy. Three eyes had partial reti nal detachment and nine had no retinal detach ment. Only one of the ten eyes with total retinal detachment achieved visual success, whereas ten of the 12 eyes with either partial detach ment or no retinal detachment achieved visual successes. Thus, the presence of total retinal detachment portended a poor visual outcome when compared with eyes with partial or no retinal detachment (P = .002).
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Fig. 2 (Alfaro and associates). Case 6. At 38 months of follow-up, visual acuity remained at 20/200. Poor visual acuity was caused by submacular and epimacular scarring from an exit wound located within the vascular arcades. Posterior vitreous detachment was observed in 16 eyes. In five eyes, the posterior vitreous face remained attached to the retina, and in one eye the status of the vitreous could not be determined from the operative note. Visual success was attained in ten eyes with a posterior vitreous detachment. No eyes without posteri or vitreous detachment attained visual success, but one eye attained anatomic success. Thus, the presence of posterior vitreous detachment was associated with more favorable visual out come (P = .035). Cryotherapy was used either alone or in con junction with endolaser therapy to achieve chorioretinal adhesion in 12 eyes, four of which achieved visual success and eight of which achieved anatomic success or had treatment failures. Ten eyes did not receive cryotherapy, of which seven eyes achieved visual success and three achieved anatomic success or had treatment failures. There was no statistically significant association between the use of cryo therapy and visual outcome (P = .19).
Discussion
Fig. 1 (Alfaro and associates). Case 15. At 14 months of follow-up, Snellen visual acuity was 20/ 50. This patient had a perforating injury to the left eye with an exit wound located well outside the vascular arcades.
Our data showed that the combined visual and anatomic successes by means of pars plana vitrectomy and scierai buckling are possible in a large percentage of eyes with single perforat ing injuries (70%, 12 of 17 eyes) sustained from shotgun pellets. Eyes with multiple perfora tions appear to have a worse prognosis, as only 40% of such cases (two of five eyes) had either functional vision or anatomic success. Physical findings at vitrectomy that portend a favorable visual outcome include the absence of total retinal detachment and the presence of posteri or vitreous detachment.
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Experimental studies have elucidated the pathobiologic characteristics of perforating eye injuries. Topping, Abrams, and Machemer 5 used a rabbit model of perforating eye trauma and found that fibroblastic proliferation oc curred along the vitreous scaffold in the injured vitreous body. In their model, traction retinal detachments were not induced, although exten sive anteroposterior fibroblastic proliferation was noted one month after injury. Further more, vitrectomy halted the fibroblastic prolife ration. 6 Cleary and Ryan7 induced traction retinal detachments and posterior vitreous detachments in rhesus macaque monkeys by means of a scierai laceration and injection of autologous blood into the vitreous cavity. Con trol monkeys that had saline solution injected into the vitreous cavity after an identical scierai laceration did not develop traction retinal de tachment, suggesting the importance of vitre ous hemorrhage in the formation of transvitreal traction. In our study, the presence of total retinal detachment portended a poor prognosis in pa tients with a perforating eye injury, as only one such patient had return of useful vision. This is consistent with data of others, 4 who also found retinal detachment to be associated with a worse prognosis in perforating eye injuries. Retinal detachment that accompanies perforat ing eye injury can result from traction, with subsequent rhegmatogenous retinal detach ment; from exudation of fluid secondary to increased intraocular inflammatory mediators and compromise of the blood-retinal barrier 8,9 ; and from subretinal accumulation of blood from choroidal bleeding. 10 Pars plana vitrec tomy controls two of these factors. Subretinal blood can be drained via retinotomy, as de scribed by Han and associates, 10 and vitrectomy removes damaged and hemorrhagic vitreous, which is a stimulus for intraocular prolifera tion, thereby preventing the development of anteroposterior traction and subsequent de tachments. Spontaneous separation of the posterior cor tical vitreous occurred in many of our patients, despite their young age, and was associated with visual success in a statistically significant number of patients. Typically, the posterior vitreous remained attached to the retina only at the exit wound, where vitreous was incarcerat ed in the wound. The association between pos terior vitreous detachment and a favorable vis ual outcome may be attributable to the following: (1) facilitation of vitrectomy, (2) obviation of manipulations to peel the vitreous face off the retina, or (3) the more complete
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vitrectomy and the removal of vitreous rem nants that could potentially provide a scaffold for fibroblastic proliferation. Experimental studies performed on monkeys to evaluate vit rectomy in eyes with penetrating injuries showed less intraocular proliferation and fewer traction retinal detachments in eyes on which complete vitrectomies had been performed, as compared with those on which core vitrecto mies had been performed. 11 Microscopic exami nation of eyes with incomplete vitrectomies showed cellular proliferation at the vitreous base and anteroposterior extension of fibroblasts on vitreous condensations. 12 Despite the use of vitrectomy, the presence of multiple ocular perforations from shotgun pel lets showed a trend toward poorer visual out come, although such association did not achieve statistical significance. In our study, this poor outcome resulted from severe intraoc ular disorganization, total retinal detachment, and retinal atrophy. Perforation of the posterior eye wall within the vascular arcades was associ ated with poor visual outcome even among eyes that achieved visual success. Direct injury to the macula, submacular hemorrhage, and sub macular and epimacular scarring all contribut ed to the poor vision in those patients who had perforations within the arcades. The use of cryotherapy in the treatment of penetrating ocular trauma has been ques tioned, with speculation that such treatment exacerbates intraocular cellular proliferation. Campochiaro, Gaskin, and Vinores 13 applied retinal cryopexy to rabbit eyes that had scierai wounds and noted the development of traction retinal detachments. In our study, cryotherapy was applied to selected retinal breaks, and we could document no difference in final visual success when comparing treated eyes with nontreated eyes. In no instance, however, had reti nal cryopexy been applied to the rupture site made by perforating missiles. In this small series, the judicious use of retinal cryopexy did not exacerbate intraocular cellular proliferation or affect visual outcome. The timing of vitrectomy in the treatment of penetrating eye injury continues to be debated. In 1982, Coleman 14 evaluated the role of early vitrectomy in penetrating trauma. Good vision was achieved in 65% of the cases when vitrec tomy was performed within 72 hours after inju ry, whereas useful vision was achieved in only 40% of those cases in which vitrectomy was delayed. Unfortunately, he did not describe the types of injuries relegated to the different surgi cal procedures, and an internal bias possibly existed whereby eyes with a more favorable
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p r o g n o s i s received earlier t r e a t m e n t . M o r e r e cently, L e m m e n a n d H e i m a n n 1 5 d e s c r i b e d 11 patients with traumatic retinal detachments t r e a t e d w i t h early v i t r e c t o m y a n d p r i m a r y silicone-oil injection, six of w h o m a t t a i n e d useful vision. We a t t e m p t e d to p e r f o r m v i t r e c t o m y t e n to 14 days after injury, a n d v i t r e c t o m y w a s p e r f o r m e d in 18 of 23 of t h e eyes (77%) b e t w e e n six a n d 21 days after injury. T h e a d v a n t a g e s of delaying v i t r e c t o m y i n c l u d e t h e o p p o r t u n i t y for m o r e a d e q u a t e p r e o p e r a t i v e e x a m i n a t i o n , in traocular hemostasis, and spontaneous separa tion of the cortical v i t r e o u s . Closely m o n i t o r i n g eyes w i t h p e n e t r a t i n g injury by m e a n s of serial u l t r a s o n o g r a p h y m a y be helpful in t i m i n g of vitrectomy. An eye w i t h a p e n e t r a t i n g injury b u t w i t h o u t r e t i n a l d e t a c h m e n t , or w i t h t r a u matic r e t i n a l d e t a c h m e n t t h a t d o e s n o t i n v o l v e the m a c u l a , is p r o b a b l y b e s t t r e a t e d b y d e l a y i n g vitrectomy for ten to 14 days, w h e r e a s the p r e s e n c e of h e m o r r h a g i c r e t i n a l d e t a c h m e n t involving the m a c u l a may n e c e s s i t a t e earlier vitrectomy, given the k n o w n toxicity of s u b r e t i nal b l o o d to the p h o t o r e c e p t o r cells. 1 6 O u r s t u d y h a d the w e a k n e s s e s i n h e r e n t in any r e t r o s p e c t i v e s t u d y in w h i c h s u b j e c t s w e r e n o t r a n d o m l y a s s i g n e d to t r e a t m e n t . An i n t e r nal bias also existed in o u r s t u d y , as p a t i e n t s w i t h n o light p e r c e p t i o n after initial r e p a i r d o n o t u s u a l l y u n d e r g o v i t r e c t o m y for p e n e t r a t i n g injuries at o u r i n s t i t u t i o n . O n e m a y t h u s c o n t e n d t h a t eyes w i t h a less favorable p r o g n o s i s w e r e e x c l u d e d from t h e r e v i e w . N e v e r t h e l e s s , o u r s t u d y w a s d e s i g n e d to e v a l u a t e specifically the role of v i t r e c t o m y a n d of i n t r a o p e r a t i v e findings in eyes w i t h p e r f o r a t i o n s as t h e y r e l a t e to visual a n d surgical s u c c e s s e s . Perforating eye injuries m a y b e successfully t r e a t e d via p a r s p l a n a v i t r e c t o m y a n d scierai b u c k l i n g . The a b s e n c e of total r e t i n a l d e t a c h m e n t a n d t h e p r e s e n c e of p o s t e r i o r v i t r e o u s d e t a c h m e n t w e r e a s s o c i a t e d w i t h a m o r e favor able p r o g n o s i s , w h e r e a s i n t r a o c u l a r d i s o r g a n i zation in eyes w i t h m u l t i p l e ocular perfora tions, and perforations involving the macular area w e r e associated w i t h a p o o r e r p r o g n o s i s .
References 1. Drummond, J., and Kielar, R. A.: Perforating ocular shotgun injuries. Relationship of ocular
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findings to pellet ballistics. South. Med. J. 69:1066, 1976. 2. Morris, R. E., Witherspoon, C. D., Feist, R. M., Byrne, J. B., Jr., and Ottemiller, D. E.: Bilateral ocular shotgun injury. Am. ). Ophthalmol. 103:695, 1987. 3. Ramsay, R. C , Cantrill, H. L., and Knobloch, W. H.: Vitrectomy for double penetrating ocular in juries. Am. J. Ophthalmol. 100:586, 1985. 4. Ryan, S. J., and Allen, A. W.: Pars plana vitrec tomy in ocular trauma. Am. J. Ophthalmol. 88:483, 1979. 5. Topping, T. M., Abrams, G. W., and Machemer, R.: Experimental double-perforating injury of the posterior segment in rabbit eyes. The natural history of intraocular proliferation. Arch. Ophthalmol. 97:735, 1979. 6. Abrams, G. W., Topping, T. M., and Machemer, R.: Vitrectomy for injury. The effect on intraocular proliferation following perforation of the posterior segment of the rabbit eye. Arch. Ophthalmol. 97:743, 1979. 7. Cleary, P.E., and Ryan, S. J.: Method of produc tion and natural history of experimental posterior penetrating eye injury in the rhesus monkey. Am. J. Ophthalmol. 88:212, 1979. 8. Gregor, Z., and Ryan, S. J.: Blood-retinal barrier after blunt trauma to the eye. Graefes Arch. Clin. Exp. Ophthalmol. 219:205, 1982. 9. Latanza, L., Alfaro, D. V., Bockman, R., Iwamoto, T., Heinemann, M. H., and Chang, S.: Leukotrienes levels in the aqueous humor following experi mental ocular trauma. Retina 8:199, 1988. 10. Han, D. P., Mieler, W. F., Schwartz, D. M., and Abrams, G. W.: Management of traumatic hem orrhagic retinal detachment with pars plana vitrec tomy. Arch. Ophthalmol. 108:1281, 1990. 11. Gregor, Z., and Ryan, S. J.: Complete and core vitrectomies in the treatment of experimental poster ior penetrating eye injury in the rhesus monkey. I. Clinical features. Arch. Ophthalmol. 101:441, 1983. 12. : Complete and core vitrectomies in the treatment of experimental posterior penetrating eye injury in the rhesus monkey. II. Histologie features. Arch. Ophthalmol. 101:446, 1983. 13. Campochiaro, P. A., Gaskin, H. C , and Vinores, S. A.: Retinal cryopexy stimulates traction retinal detachment formation in the presence of an ocular wound. Arch. Ophthalmol. 105:1567, 1987. 14. Coleman, D. J.: Early vitrectomy in the man agement of the severely traumatized eye. Am. J. Ophthalmol. 93:543, 1982. 15. Lemmen, K. D., and Heimann, K.: FrühVitrektomie mit primärer Silikonölinjektion bei schwerstverletzten Augen. Klin. Monatsbl. Augenheilkd. 193:594, 1988. 16. Glatt, H., and Machemer, R.: Experimental subretinal hemorrhage in rabbits. Am. J. Ophthal mol. 94:762, 1982.
Pars plana vitrectomy and scierai buckling were performed on 22 eyes of 19 patients for treatment of perforating eye injuries from shotgun pellets. We reviewed the intraoperative findings at the time of vitrectomy to determine what factors might influence final visual acuity. The presence of a total retinal detachment at vitrectomy portended a poor prognosis when compared with eyes without total retinal detachment, as only one of ten eyes with total retinal detachment obtained useful vision (P = .002). Preoperative separation of the posterior vitreous was associated with a favorable outcome when compared with the absence of posterior vitreous detachment (P = .035), as ten of 16 eyes with posterior vitreous detachment at the time of vitrectomy ultimately achieved functional vision. The locations of the exit wounds did not affect visual success in the overall series of patients. However, in the patients who achieved visual success, exit wounds outside the vascular arcades were more likely to be associated with final visual acuities of, or better than, 20/70 than were those within the arcades (P = .022). Other prognostic factors, such as the number of perforations and the use of cryotherapy, were also examined for their effects on final visual outcome. However, these factors did not appear to affect visual outcome statistically.
Accepted for publication March 16, 1992. From the Department of Ophthalmology, University of Southern California School of Medicine, the Doheny Eye Institute, and Los Angeles County-University of Southern California Medical Center, Los Angeles, Cali fornia. This study was supported in part by a Core Grant for Vision Research (EY03040) from the National Insti tutes of Health, Bethesda, Maryland. Reprint requests to Peter E. Liggett, M.D., Yale Univer sity School of Medicine, Yale University, 330 Cedar St., New Haven, CT 06510.
PERFORATING INJURIES OF THE EYE result from a missile entering the eye, penetrating the vitre ous cavity, traversing the posterior segment, and exiting the eye posteriorly. A large series of such eyes showed that eyes with perforating injuries have poor visual outcomes, 1 although more recent studies have suggested that vitrec tomy may help to salvage some of these eyes.2,3 Retinal injury, retinal detachment, and the status of the posterior vitreous are thought to influence the final outcome in patients with perforating injury involving the posterior seg ment. To assess those factors that might predict outcome, we reviewed the records of 19 consec utive patients who had sustained perforating eye injuries from shotgun pellets; we evaluated the intraoperative findings at the time of vitrec tomy to determine what factors might influence final visual acuity.
Patients and Methods We reviewed the records of 19 consecutive patients (22 eyes) who underwent pars plana vitrectomy and scierai buckling for perforating injuries of the eye sustained from shotgun pel lets from July 1986 through February 1990. One additional patient treated during this period was excluded from the study because he was lost to follow-up immediately after surgical procedures. Hospital records and operative notes provided patient age, initial visual acuity, perforation sites, elapsed time from injury to vitrectomy, presence of retinal detachment, presence of posterior vitreous detachment, lo cations of the exit wounds, anatomic result, and final visual acuity. All patients were followed up for six to 48 months. Eighteen of the 19 patients were male, and ages ranged from 17 to 40 years; all were either black or Hispanic and had been assaulted. All
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patients had visual acuity of light perception or hand motion at the time of initial examination. All patients underwent primary repair of the perforating injuries within 24 hours of the as sault. Corneal wounds were repaired before conjunctival peritomy. If prolapsed subconjunctival uvea, subconjunctival blood, or both, suggested a scierai perforation, the conjunctiva and Tenon's capsule were locally dissected away from the wound. Prolapsed vitreous was excised with a dry, cotton-tipped applicator and scissors. Scierai lacerations were repaired with 8-0 nylon suture. After repair of the cornea and anterior sclera, a 360-degree peritomy was performed and all four quadrants of the globe were inspected by using a Schepens retractor and a cotton-tipped applicator. Each of the lateral recti muscles was then isolated and re tracted to allow visualization underneath the muscle. If scierai perforation was seen at the insertion of the muscle, the muscle was de tached from the globe and then reinserted after repair. Posterior perforations were not repaired if retraction did not permit full visualization of the wound. In the period between primary repair and vitrectomy, the patients were examined with serial ultrasonography to assess the status of the retina and posterior vitreous. In most cases, vitrectomy was performed during the second or third week after trauma, although some pa tients chose to postpone surgical procedures. We used a dual-function aspiration cutting sys tem for vitrectomy. The lens was salvaged if possible, but pars plana lensectomy was per formed in cases of cataract or lens subluxation. A core vitrectomy was performed to remove media opacities, and the posterior hyaloid was stripped from the retinal surface when possible. Attempts were made to trim the vitreous base with the cutting instrument in conjunction with scierai indentation. Cortical vitreous was re moved from the posterior exit wounds up to the edges of incarcerated tissue. A broad scierai buckle (No. 287) with an overlying No. 240 band secured by a No. 70 sleeve was placed around each eye. Retinal breaks were treated with cryopexy or intraocular photocoagulation. Prolonged intraocular tamponade with sulfur hexafluoride (SF6) or perfluoropropane (C3F8) was used in 12 eyes; silicone oil was used in three eyes with severe intraocular disorganiza tion and total retinal detachment. We defined visual and anatomic successes according to the criteria of Ryan and Allen. 4 Vis ual success was defined as postoperative visual acuity of 5/200 or greater (by Snellen chart) if preoperative visual acuity were light percep
tion or hand motions. Anatomic success was defined as successful reconstruction of the globe but failure to meet the criteria for visual success. A (through-and-through) perforating eye in jury was defined as one in which a pellet en tered the eye by penetrating the cornea or anterior sclera, and exited the eye by perforat ing the sclera posteriorly, into the orbit. An eye with multiple perforations was defined as one with two or more perforations of the sclera. Fisher's exact (two-tailed) tests were per formed to test for association between the end points (visual success) and the following possi ble prognostic factors: retinal detachment, pos terior vitreous detachment, number of perfora tions, perforation within the vascular arcade, and the use of cryotherapy.
Results Vitrectomy was performed on 16 eyes be tween one and three weeks after injury. Vitrec tomy was performed on three eyes 23 days after injury and vitrectomy was performed in three eyes after more than one month from the time of trauma. Overall, visual success was achieved in 11 eyes, anatomic success was achieved in three eyes, and treatment failed in eight eyes. Final visual acuity fell within the range of 5/200 to 20/30. Final visual acuity of, or better than, 20/70 was achieved in six of the 11 eyes with visual success. In three eyes that were recon structed anatomically, visual acuity remained at hand motions and 2/200. Eight eyes could not be reconstructed, resulting in no light per ception. Seventeen eyes had one perforation. Of the five eyes that had multiple perforations, one eye had a pellet that penetrated the anterior sclera at one entry site and fragmented into two separate fragments, which then perforated the posterior eye wall at two separate exit wounds; three eyes had two perforations from two pel lets; and one had three perforations from three pellets. Of the 17 eyes with one perforation, ten were visual successes, two were anatomic suc cesses, and treatment failed in five. Of the five eyes with multiple perforations, one was a visual success, one was an anatomic success, and treatment failed in three. Thus, treatment failed in five of the 17 eyes (29%) with one perforation, whereas treatment failed in three of the five eyes (60%) with multiple perfora tions. Multiple perforations (from one or multi-
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pie pellets) appeared to be associated with worse outcome. However, such association did not achieve statistical significance (P = .31). Locations of the exit wounds with respect to the vascular arcades were also analyzed as a prognostic factor for visual outcome. Nine eyes had exit wounds within the vascular arcades and 11 eyes had exit wounds outside the ar cades. The locations of the exit wounds could not be determined from the operative notes on two eyes, which were therefore not included in this analysis. Five of the nine eyes with a perforation within the vascular arcades achieved visual success. Six of the 11 eyes with a perforation outside the arcades achieved visu al success. Thus, the location of the exit wound did not influence final visual acuity in the overall series. However, among the eyes that achieved visual success, visual acuities were better in those eyes that had exit wounds out side the vascular arcades (Fig. 1) as compared with eyes in which exit wounds were located within the vascular arcades (Fig. 2). When only outcomes of eyes that achieved visual success were analyzed, none of the five eyes with exit wounds within the vascular arcades had visual acuities of 20/70 or better, whereas all six eyes with exit wounds outside the vascular arcades achieved final visual acuities of 20/70 or better (P = .022). Ten eyes had total retinal detachment at the time of vitrectomy. Three eyes had partial reti nal detachment and nine had no retinal detach ment. Only one of the ten eyes with total retinal detachment achieved visual success, whereas ten of the 12 eyes with either partial detach ment or no retinal detachment achieved visual successes. Thus, the presence of total retinal detachment portended a poor visual outcome when compared with eyes with partial or no retinal detachment (P = .002).
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Fig. 2 (Alfaro and associates). Case 6. At 38 months of follow-up, visual acuity remained at 20/200. Poor visual acuity was caused by submacular and epimacular scarring from an exit wound located within the vascular arcades. Posterior vitreous detachment was observed in 16 eyes. In five eyes, the posterior vitreous face remained attached to the retina, and in one eye the status of the vitreous could not be determined from the operative note. Visual success was attained in ten eyes with a posterior vitreous detachment. No eyes without posteri or vitreous detachment attained visual success, but one eye attained anatomic success. Thus, the presence of posterior vitreous detachment was associated with more favorable visual out come (P = .035). Cryotherapy was used either alone or in con junction with endolaser therapy to achieve chorioretinal adhesion in 12 eyes, four of which achieved visual success and eight of which achieved anatomic success or had treatment failures. Ten eyes did not receive cryotherapy, of which seven eyes achieved visual success and three achieved anatomic success or had treatment failures. There was no statistically significant association between the use of cryo therapy and visual outcome (P = .19).
Discussion
Fig. 1 (Alfaro and associates). Case 15. At 14 months of follow-up, Snellen visual acuity was 20/ 50. This patient had a perforating injury to the left eye with an exit wound located well outside the vascular arcades.
Our data showed that the combined visual and anatomic successes by means of pars plana vitrectomy and scierai buckling are possible in a large percentage of eyes with single perforat ing injuries (70%, 12 of 17 eyes) sustained from shotgun pellets. Eyes with multiple perfora tions appear to have a worse prognosis, as only 40% of such cases (two of five eyes) had either functional vision or anatomic success. Physical findings at vitrectomy that portend a favorable visual outcome include the absence of total retinal detachment and the presence of posteri or vitreous detachment.
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AMERICAN JOURNAL OF OPHTHALMOLOGY
Experimental studies have elucidated the pathobiologic characteristics of perforating eye injuries. Topping, Abrams, and Machemer 5 used a rabbit model of perforating eye trauma and found that fibroblastic proliferation oc curred along the vitreous scaffold in the injured vitreous body. In their model, traction retinal detachments were not induced, although exten sive anteroposterior fibroblastic proliferation was noted one month after injury. Further more, vitrectomy halted the fibroblastic prolife ration. 6 Cleary and Ryan7 induced traction retinal detachments and posterior vitreous detachments in rhesus macaque monkeys by means of a scierai laceration and injection of autologous blood into the vitreous cavity. Con trol monkeys that had saline solution injected into the vitreous cavity after an identical scierai laceration did not develop traction retinal de tachment, suggesting the importance of vitre ous hemorrhage in the formation of transvitreal traction. In our study, the presence of total retinal detachment portended a poor prognosis in pa tients with a perforating eye injury, as only one such patient had return of useful vision. This is consistent with data of others, 4 who also found retinal detachment to be associated with a worse prognosis in perforating eye injuries. Retinal detachment that accompanies perforat ing eye injury can result from traction, with subsequent rhegmatogenous retinal detach ment; from exudation of fluid secondary to increased intraocular inflammatory mediators and compromise of the blood-retinal barrier 8,9 ; and from subretinal accumulation of blood from choroidal bleeding. 10 Pars plana vitrec tomy controls two of these factors. Subretinal blood can be drained via retinotomy, as de scribed by Han and associates, 10 and vitrectomy removes damaged and hemorrhagic vitreous, which is a stimulus for intraocular prolifera tion, thereby preventing the development of anteroposterior traction and subsequent de tachments. Spontaneous separation of the posterior cor tical vitreous occurred in many of our patients, despite their young age, and was associated with visual success in a statistically significant number of patients. Typically, the posterior vitreous remained attached to the retina only at the exit wound, where vitreous was incarcerat ed in the wound. The association between pos terior vitreous detachment and a favorable vis ual outcome may be attributable to the following: (1) facilitation of vitrectomy, (2) obviation of manipulations to peel the vitreous face off the retina, or (3) the more complete
July, 1992
vitrectomy and the removal of vitreous rem nants that could potentially provide a scaffold for fibroblastic proliferation. Experimental studies performed on monkeys to evaluate vit rectomy in eyes with penetrating injuries showed less intraocular proliferation and fewer traction retinal detachments in eyes on which complete vitrectomies had been performed, as compared with those on which core vitrecto mies had been performed. 11 Microscopic exami nation of eyes with incomplete vitrectomies showed cellular proliferation at the vitreous base and anteroposterior extension of fibroblasts on vitreous condensations. 12 Despite the use of vitrectomy, the presence of multiple ocular perforations from shotgun pel lets showed a trend toward poorer visual out come, although such association did not achieve statistical significance. In our study, this poor outcome resulted from severe intraoc ular disorganization, total retinal detachment, and retinal atrophy. Perforation of the posterior eye wall within the vascular arcades was associ ated with poor visual outcome even among eyes that achieved visual success. Direct injury to the macula, submacular hemorrhage, and sub macular and epimacular scarring all contribut ed to the poor vision in those patients who had perforations within the arcades. The use of cryotherapy in the treatment of penetrating ocular trauma has been ques tioned, with speculation that such treatment exacerbates intraocular cellular proliferation. Campochiaro, Gaskin, and Vinores 13 applied retinal cryopexy to rabbit eyes that had scierai wounds and noted the development of traction retinal detachments. In our study, cryotherapy was applied to selected retinal breaks, and we could document no difference in final visual success when comparing treated eyes with nontreated eyes. In no instance, however, had reti nal cryopexy been applied to the rupture site made by perforating missiles. In this small series, the judicious use of retinal cryopexy did not exacerbate intraocular cellular proliferation or affect visual outcome. The timing of vitrectomy in the treatment of penetrating eye injury continues to be debated. In 1982, Coleman 14 evaluated the role of early vitrectomy in penetrating trauma. Good vision was achieved in 65% of the cases when vitrec tomy was performed within 72 hours after inju ry, whereas useful vision was achieved in only 40% of those cases in which vitrectomy was delayed. Unfortunately, he did not describe the types of injuries relegated to the different surgi cal procedures, and an internal bias possibly existed whereby eyes with a more favorable
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p r o g n o s i s received earlier t r e a t m e n t . M o r e r e cently, L e m m e n a n d H e i m a n n 1 5 d e s c r i b e d 11 patients with traumatic retinal detachments t r e a t e d w i t h early v i t r e c t o m y a n d p r i m a r y silicone-oil injection, six of w h o m a t t a i n e d useful vision. We a t t e m p t e d to p e r f o r m v i t r e c t o m y t e n to 14 days after injury, a n d v i t r e c t o m y w a s p e r f o r m e d in 18 of 23 of t h e eyes (77%) b e t w e e n six a n d 21 days after injury. T h e a d v a n t a g e s of delaying v i t r e c t o m y i n c l u d e t h e o p p o r t u n i t y for m o r e a d e q u a t e p r e o p e r a t i v e e x a m i n a t i o n , in traocular hemostasis, and spontaneous separa tion of the cortical v i t r e o u s . Closely m o n i t o r i n g eyes w i t h p e n e t r a t i n g injury by m e a n s of serial u l t r a s o n o g r a p h y m a y be helpful in t i m i n g of vitrectomy. An eye w i t h a p e n e t r a t i n g injury b u t w i t h o u t r e t i n a l d e t a c h m e n t , or w i t h t r a u matic r e t i n a l d e t a c h m e n t t h a t d o e s n o t i n v o l v e the m a c u l a , is p r o b a b l y b e s t t r e a t e d b y d e l a y i n g vitrectomy for ten to 14 days, w h e r e a s the p r e s e n c e of h e m o r r h a g i c r e t i n a l d e t a c h m e n t involving the m a c u l a may n e c e s s i t a t e earlier vitrectomy, given the k n o w n toxicity of s u b r e t i nal b l o o d to the p h o t o r e c e p t o r cells. 1 6 O u r s t u d y h a d the w e a k n e s s e s i n h e r e n t in any r e t r o s p e c t i v e s t u d y in w h i c h s u b j e c t s w e r e n o t r a n d o m l y a s s i g n e d to t r e a t m e n t . An i n t e r nal bias also existed in o u r s t u d y , as p a t i e n t s w i t h n o light p e r c e p t i o n after initial r e p a i r d o n o t u s u a l l y u n d e r g o v i t r e c t o m y for p e n e t r a t i n g injuries at o u r i n s t i t u t i o n . O n e m a y t h u s c o n t e n d t h a t eyes w i t h a less favorable p r o g n o s i s w e r e e x c l u d e d from t h e r e v i e w . N e v e r t h e l e s s , o u r s t u d y w a s d e s i g n e d to e v a l u a t e specifically the role of v i t r e c t o m y a n d of i n t r a o p e r a t i v e findings in eyes w i t h p e r f o r a t i o n s as t h e y r e l a t e to visual a n d surgical s u c c e s s e s . Perforating eye injuries m a y b e successfully t r e a t e d via p a r s p l a n a v i t r e c t o m y a n d scierai b u c k l i n g . The a b s e n c e of total r e t i n a l d e t a c h m e n t a n d t h e p r e s e n c e of p o s t e r i o r v i t r e o u s d e t a c h m e n t w e r e a s s o c i a t e d w i t h a m o r e favor able p r o g n o s i s , w h e r e a s i n t r a o c u l a r d i s o r g a n i zation in eyes w i t h m u l t i p l e ocular perfora tions, and perforations involving the macular area w e r e associated w i t h a p o o r e r p r o g n o s i s .
References 1. Drummond, J., and Kielar, R. A.: Perforating ocular shotgun injuries. Relationship of ocular
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findings to pellet ballistics. South. Med. J. 69:1066, 1976. 2. Morris, R. E., Witherspoon, C. D., Feist, R. M., Byrne, J. B., Jr., and Ottemiller, D. E.: Bilateral ocular shotgun injury. Am. ). Ophthalmol. 103:695, 1987. 3. Ramsay, R. C , Cantrill, H. L., and Knobloch, W. H.: Vitrectomy for double penetrating ocular in juries. Am. J. Ophthalmol. 100:586, 1985. 4. Ryan, S. J., and Allen, A. W.: Pars plana vitrec tomy in ocular trauma. Am. J. Ophthalmol. 88:483, 1979. 5. Topping, T. M., Abrams, G. W., and Machemer, R.: Experimental double-perforating injury of the posterior segment in rabbit eyes. The natural history of intraocular proliferation. Arch. Ophthalmol. 97:735, 1979. 6. Abrams, G. W., Topping, T. M., and Machemer, R.: Vitrectomy for injury. The effect on intraocular proliferation following perforation of the posterior segment of the rabbit eye. Arch. Ophthalmol. 97:743, 1979. 7. Cleary, P.E., and Ryan, S. J.: Method of produc tion and natural history of experimental posterior penetrating eye injury in the rhesus monkey. Am. J. Ophthalmol. 88:212, 1979. 8. Gregor, Z., and Ryan, S. J.: Blood-retinal barrier after blunt trauma to the eye. Graefes Arch. Clin. Exp. Ophthalmol. 219:205, 1982. 9. Latanza, L., Alfaro, D. V., Bockman, R., Iwamoto, T., Heinemann, M. H., and Chang, S.: Leukotrienes levels in the aqueous humor following experi mental ocular trauma. Retina 8:199, 1988. 10. Han, D. P., Mieler, W. F., Schwartz, D. M., and Abrams, G. W.: Management of traumatic hem orrhagic retinal detachment with pars plana vitrec tomy. Arch. Ophthalmol. 108:1281, 1990. 11. Gregor, Z., and Ryan, S. J.: Complete and core vitrectomies in the treatment of experimental poster ior penetrating eye injury in the rhesus monkey. I. Clinical features. Arch. Ophthalmol. 101:441, 1983. 12. : Complete and core vitrectomies in the treatment of experimental posterior penetrating eye injury in the rhesus monkey. II. Histologie features. Arch. Ophthalmol. 101:446, 1983. 13. Campochiaro, P. A., Gaskin, H. C , and Vinores, S. A.: Retinal cryopexy stimulates traction retinal detachment formation in the presence of an ocular wound. Arch. Ophthalmol. 105:1567, 1987. 14. Coleman, D. J.: Early vitrectomy in the man agement of the severely traumatized eye. Am. J. Ophthalmol. 93:543, 1982. 15. Lemmen, K. D., and Heimann, K.: FrühVitrektomie mit primärer Silikonölinjektion bei schwerstverletzten Augen. Klin. Monatsbl. Augenheilkd. 193:594, 1988. 16. Glatt, H., and Machemer, R.: Experimental subretinal hemorrhage in rabbits. Am. J. Ophthal mol. 94:762, 1982.
