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Ocular Nail Gun Injuries
Ocular Nail Gun Injuries Bailey L. Lee, MD,l Paul Sternberg, Jr, MD2 Purpose: Penetrating ocular trauma resulting from nails can have disastrous visual consequences. Ocular nail gun injuries occur when a nail propelled at high velocity penetrates the globe. The authors report four consecutive patients with ocular injuries resulting from nail guns. Methods: Four patients with ocular nail gun injuries are described: one with scleral penetrating injury, one with corneal penetrating injury, and two with perforating (throughand-through) injuries of the globe. Results: Three of the four patients recovered good visual acuity after surgical intervention. Conclusion: Although dependent on the site of impact, the visual prognosis may be less severe than expected because the nail penetrates the eye at a high velocity such that there are less contusive forces. Adherence to safety precautions involving the use of nail guns as well as the obligatory use of safety glasses should reduce the incidence of these injuries. Ophthalmology 1996; 103:1453-1457
Nail guns are powerful industrial tools used to drive nails or similar fasteners such as bolts, studs, or staples into wood, metal, or concrete. Powered by compressed air, a spring mechanism, or an explosive cartridge, nail guns can propel fasteners with a velocity of 100 to 150 rnI second. Their industrial use began in the 1950s, and various injuries have been reported as a result of their use. The central nervous system, lung, heart, abdominal viscera, and extremities have been areas affected, sometimes with fatal consequences. 1 - 8 There are no reported series of penetrating ocular nail gun injuries in the literature, although there are single cases described in reports in the nonophthalmic literature (1 patient had a nail that penetrated the orbit without ocular penetration,3 whereas another describes a corneoscleral laceration with extruding ocular contents 2). In this article, we describe four
Originally received: January 16. 1996. Revision accepted: May 22, 1996. J Department of Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio. 2 Emory Eye Center, Atlanta. Presented in part at the Vitreous Society, London, England, August 1995, and at the American Academy of Ophthalmology Annual Meeting, Atlanta, OctINov 1995. Supported in part by departmental core grant P30EY06360 from the National Institutes of Health, Bethesda, Maryland, and by an unrestricted grant from Research to Prevent Blindness, Inc, New York, New York. Reprint requests to Bailey L. Lee, MD, University of Texas Health Science Center at San Antonio, Department of Ophthalmology, 7703 Floyd Curl Dr, San Antonio, TX 78284-6230.
consecutive patients with ocular nail gun injuries and their management.
Case Reports Case 1. A 41-year-old man was struck in the left eye with a nail while using a nail gun at work. The nail ricocheted from the piece of wood that he was nailing. The patient noticed an immediate drop in his visual acuity and saw his local ophthalmologist who referred him to the Emory Eye Center. On examination, his visual acuity was 20115 in the right eye and 20/40 in the left. There was no afferent pupillary defect. The anterior segment of the left eye showed a self-sealing corneal laceration paracentrally at approximately 10 o'clock with involvement of the underlying iris. The corneal wound was Seidel-negative, with no evidence of iris incarceration. There was no cellular reaction in either the aqueous or the vitreous. Gonioscopy showed the angle to be open without evidence of a foreign body. After the pupil was dilated, it was evident that the anterior capsule was penetrated underneath the iris with associated localized opacification of the lens. Results of funduscopic examination were unremarkable. Computed tomography scan of the orbit did not show any evidence of an intraocular foreign body. The patient was given oral and topical ciprofioxacin. Visual acuity decreased to 20/60 over the following week due to increasing lenticular opacification. The patient underwent phacoemulsification with posterior chamber lens implant without complications. Postoperatively, his visual acuity improved to 20/20. Case 2. A 21-year-old man was struck in the left eye by a nail fired from a nail gun. The nail ricocheted from the piece of wood that he was nailing and was protruding from the globe
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Figure 1. Case 2. A bent, barbed nail protrudes from the comeoscleral limbus, resulting from a ricochet nail gun injury. Arrow = the barbed portion of the nail.
when he presented to the Emory Eye Center (Fig 1). On examination, he was in moderate distress with a visual acuity of 201 40 in the right eye and counting fingers in the left. There was no afferent pupillary defect. A large, bent, barbed nail protruded from the corneosclerallimbus at the 4-o'clock meridian. There was limitation of motility secondary to the pain. He was taken to the operating room where careful examination of the anterior and posterior segment was completed. The nail entered the corneosclerallimbus and passed superiorly and posteriorly into the vitreous space, apparently b/ypassing the iris and lens. The nail was removed without difficulty, and the prolapsed vitreous was excised with sharp scissors. The scleral laceration then was closed with subsequent intravitreal injection of vancomycin (l mg) and amikacin (400 fJ,g). Results offunduscopic examination showed commotio retinae in the macula without any retinal tears or detachment. Postoperatively, he received intravenous cefazolin and topical prednisolone acetate, atropine, and gentamicin. Cultures of the nail did not show growth of any organisms. During the next week, a cataract developed that decreased his vision to counting fingers. Ultrasound showed that the retina was attached with a vitreous hemorrhage. Ten days after the initial injury, he underwent pars plana lensectomy and vitrectomy with prophylactic encircling scleral buckle with a 41 band. His visual acuity improved to 20/20, with aphakic contact lens correction. Case 3. A 25-year-old man was struck in the right eye with a nail. A nail gun was discharged accidentally while he held it on his knee. He stated that the nail projected from his eye, and he removed the nail himself. That day, he presented to the Veterans Administration Hospital in Decatur, Georgia, where a nasal-scleral laceration was repaired. He did well immediately postoperatively, but I month later he was referred to the Emory Eye Center because of persistent photopsia. On examination, visual acuity was 20/30 in the right eye and 20/20 in the left. There was no afferent pupillary defect. The anterior segment showed a clear cornea and lens, with trace cell and flare in the anterior chamber. Nylon sutures could be seen underneath the conjunctiva in the nasal-scleral area, approximately 5 mm posterior to the limbus at the 3-o'clock meridian. Results of funduscopic examination showed a transvitreal band that extended
1454
posteriorly from the entrance site nasally to underneath the inferotemporal arcade (Fig 2A). There was associated vitreous hemorrhage and vitreoretinal traction at the impact site with subretinal fluid. The patient underwent an encircling scleral buckle with a 41 band and pars plana vitrectomy with transection of the transvitreal band and membrane stripping. Postoperatively, the vitreoretinal traction was relieved (Figs 2B), and the patient's best-corrected visual acuity was 20/20. Case 4. A 22-year-old man reported a history of being struck by a board in the right eye while in a woodworking class. On initial examination, vision in the right eye was hand motions. Anterior segment examination showed a corneal laceration inferiorly at the 6-o'clock meridian to the limbus, with prolapse of iris and lens material through the wound. The anterior chamber was flat, and the eye was hypotonus. The patient was taken to the operating room where the corneal laceration was repaired with a lensectomy, anterior vitrectomy, and insertion of a posterior chamber lens. Postoperatively, the patient had persistent pain, especially with movement of the eye, and ocular inflammation, with vision decreased to bare light perception. On ultrasound examination, a very highly reflective nonmobile area of opacity was seen in the mid-vitreous cavity with a sonolucent
Figure 2, Case 3. A, impact site along the inferotemporal arcade with a pre-retinal hemorrhage and a transvitreal band extending to the entrance site. B, postoperative fundus of case 3 with the impact site along the posterior aspect of the scleral buckle.
Lee and Sternberg· Nail Gun Injuries Table 1. Summary of Ocular Nail Gun Injuries Case No. 1
2 3
4
Type of Injury
Mechanism
Corneal laceration Scleral laceration Perforation Perforation
Ricochet Ricochet Mid-air firing Over-penetration
Vision Outcome
20/20 20/20 20/20 Enucleation
trail extending through the posterior pole and a retinal detachment (Fig 3A), whereas radiologic studies showed a linear metallic foreign body that appeared to be a nail in the right globe extending into the maxillary sinus (Figs 3B and 3C). The patient later recalled that his head was directly behind a cabinet drawer that was being nailed with a nail gun when he was struck with a nail in the right eye. The patient was taken back to the operating room 12 days after the primary repair. During the pars plana vitrectomy, the retina clearly was necrotic and completely detached. The head of the nail was located in the macula. In view of the limited visual prognosis, an enucleation was performed. However, to complete the enucleation, the nail had to be removed because it had impaled the globe to the medial wall of the orbit. This was done with forceps through the cataract incision while the nail was simultaneously advanced out of the maxillary sinus through a Caldwell-Luc incision. The patient did well postoperatively. Results of histopathologic examination of the globe showed early siderosis bulbi without evidence of endophthalmitis.
Discussion
Figure 3. A, B-scan of case 4 shows highly reflective nonmobile mass (arrow) with marked shadowing consistent with an intraocular foreign body. B, radiograph of case 4 shows linear metallic foreign body in the orbit extending into the maxillary sinus. C, axial computed tomography scan shows metallic intraocular foreign body (arrow) of case 4.
Proper training of nail gun operators and use of safety designs should reduce the incidence of injury. Nail guns must be pressed firmly against a solid surface to be fired. However, this safety precaution commonly is circumvented by its user, leading to mid-air firing. The presence of a muzzle safety shield can decrease the likelihood of ricochet or shattering-type injury. Over-penetration type injuries can be reduced by the selection of the appropriate power load for a particular job. Also the operator and assistants should wear the appropriate protective wear such as safety glasses to help prevent injuries, as well as avoid being situated behind an area that is to be nailed. The configuration or shape of the nail can provide clues to the trajectory of the nail. Steel nails that are bent are due to a ricochet injury, whereas straight-nail injuries are most probably due to over-penetration of the material being nailed or accidental mid-air firing.3 Table 1 summarizes the type and mechanism of injury, as well as the final visual outcome. In case 2, the nail was bent and indicated a ricochet-type of injury, whereas in case 4 the nail on the radiologic studies was straight, suggesting a mid-air firing or over-penetration type of injury. When a nail gun injury occurs, removal of the nail may be complicated by the presence of metallic barbs on the nail (as in case 2). The nails that are loaded into the nail guns are held together either by a resin or copper
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Figure 4. A strip of nails held to together by copper wires {arrow} that are loaded into a nail gun.
wire. The metallic barbs consists of fragments of the copper wire used to join the nails together that are preloaded into the nail gun (Fig 4). When the gun is fired, pieces of copper wire are sheared off the strip with the nail and remain attached to the nail by an adhesive resin. The metallic barb present is akin to those seen in fishhooks described in ocular penetrating injuries, and caution should be exercised in removing them to minimize tissue trauma. 9• IO Proper management of nail gun injuries is prompt recognition and attention, not only to the immediate concern of an intraocular foreign body or possible associated endophthalmitis, but also to the delayed sequelae of ocular trauma such as retinal detachment. The initial management in all patients with this type of injury should be the expeditious removal of the nail and repair of the laceration. In case 4, the presence of an intraocular foreign body was not suspected until several days after the primary repair. In case 2, the nail was removed during the primary repair, whereas in case 1 the nail penetrated the cornea with a self-sealing laceration. In case 3, the patient removed the nail himself. Previous authors have debated immediate versus delayed vitrectomy for ocular trauma, 11-15 but for instances of intraocular foreign bodies a vitrectomy usually is required for their removal in the primary repair. 16.17 The procedures of the three patients who underwent vitrectomy were performed from 10 days to 1 month after the initial injury. Whether immediate vitrectomy and removal of the nail in case 4 would have salvaged any useful vision is unlikely in view of the exit site in the macula. However, early recognition of the intraocular foreign body may have prevented siderosis bulbi. There also has been discussion in the literature on the benefits of prophylactic scleral buckling on traumatized eyes to reduce the incidence of retinal detachment. 13 •18 In cases 2 and 3 with scleral penetrating injuries, a scleral buckle was placed. In case 1 with only corneal penetration, a scleral buckle was not performed because there was no concern about an incarcerated retina or vitreous into the wound as with a scleral laceration. The visual prognosis after trauma has been correlated
1456
to various factors such as preoperative visual acuity, afferent pupillary defect, site of laceration, and type of injury. 15,18-20 In cases of perforating injuries, the mechanism of injury (either a missile versus a sharp object) and the state of the macula are important prognostic indicators of final visual acuity.21 A missile-type injury, such as that from a BB gun, requires great energy to create a blunt opening anteriorly.22-24 This results in tremendous contusive force transmitted to the globe. The mechanism of injury in a nail gun injury has both a missile and sharp object-type component. Three of the four patients had a good visual outcome. This may be because the sharp object type of injury causes less contusive forces, even though the nail is fired at high velocity with a component of a missile type of injury. In summary, we describe four patients with ocular injuries resulting from nail guns. Although three of the four patients had good visual outcome after surgical intervention, the best management plan would be prevention through proper education and the use of protective eye wear.
References 1. Lowery JC. Industrial nail gun injuries. Injury 1973;5:5962. 2. Lyons FR. Industrial nail gun injuries. Med J Aust 1983;2:483-6. 3. McCorkell SJ, Harley JD, Cummings D. Nail-gun injuries. Accident, homicide, or suicide? Am J Forensic Med Pathol 1986; 7: 192-5. 4. Edlich RF, Silloway KA, Rodeheaver T, et al. Industrial nail gun injuries. Compr Ther 1986; 12:4-46. 5. Thomas MD, Siu K. An unusual cranial injury caused by an industrial nail-gun. Med J Aust 1987; 147:602-3. 6. Barber FA. Penetrating knee injuries: the nail gun. Arthroscopy 1989;5:172-5. 7. Schor JS, Horowitz MD, Bringaze WL 3d, Thurer RJ. Industrial nail gun injuries. South Med J 1991;84:922-3. 8. Kenny NW, Kay PR, Haines JF. Nail gun injuries to the hand. J Hand Surg 1992 199217:577-8. 9. Mandelcorn MS, Crichton A. Fish hook removal from vitreous and retina. Case report. Arch Ophthalmol 1989; 107:493. 10. Aiello LP, Iwamoto M, Guyer DR. Penetrating ocular fishhook injuries. Surgical management and long-term visual outcome. Ophthalmology 1992; 99:862-6. II. Coleman DJ. Early vitrectomy in the management of the severely traumatized eye. Am J Ophthalmol 1982;93:543-51. 12. Ryan SJ, Allen AW. Pars plana vitrectomy in ocular trauma. Am J Ophthalmol 1979;88:483-91. 13. Brinton GS, Aaberg TM, Resser FH, et al. Surgical results in ocular trauma involving the posterior segment. Am J OphthalmolI982;93:271-8. 14. de Juan E, Sternberg P, Michels RG. Timing of vitrectomy after penetrating ocular injuries. Ophthalmology 1984; 91:1072-4. 15. Ahmadieh H, Soheilian M, Sajjadi H, et al. Vitrectomy in ocular trauma. Factors influencing final visual outcome. Retina 1993; 13: 107 -13. 16. Slusher MM. Intraretinal foreign bodies: management and observations. Retina 1990; lO(suppl):S50-4. 17. De Bustros S, Michels RG, Glaser BM. Evolving concepts
Lee and Sternberg in the management of posterior segment penetrating ocular injuries. Retina 1990; 10(suppl):S72-5. 18. Hutton WL, Fuller DG. Factors influencing final visual results in severely injured eyes. Am J Ophthalmol 1984; 97:715-22. 19. de Juan E, Sternberg P, Michels RG. Penetrating ocular injUlies: types of injuries and visual results. Ophthalmology 1983;90:1318-22. 20. Sternberg P, de Juan E, Michels RG, Auer C. Multivariate analysis of prognositic factors in penetrating injuries. Am J OphthalmoI1984;98 :467-72.
Nail Gun Injuries 21. Martin DF, Meredith TA , Topping TM, et al. Perforating (through-and-through) injuries ofthe globe. Surgical results with vitrectomy. Arch Ophtha1moI1991;109:951-6. 22. Sternberg P, de Juan E, Green WR, et al. Ocular BB injuries. Ophthalmology 1984; 91: 1269-77. 23. Tillet CW, Rose HW Herget C. High-speed photographic study of perforating ocular injury by the BB. Am J Ophthalmol 1962;54:675-88. 24. DeLori F, Pomerantzeff 0, Cox MS. Deformation of the globe under high-speed impact: its relation to contusion injuries. Invest Ophthalmol Vis Sci 1969;8:290-301.
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Nail guns are powerful industrial tools used to drive nails or similar fasteners such as bolts, studs, or staples into wood, metal, or concrete. Powered by compressed air, a spring mechanism, or an explosive cartridge, nail guns can propel fasteners with a velocity of 100 to 150 rnI second. Their industrial use began in the 1950s, and various injuries have been reported as a result of their use. The central nervous system, lung, heart, abdominal viscera, and extremities have been areas affected, sometimes with fatal consequences. 1 - 8 There are no reported series of penetrating ocular nail gun injuries in the literature, although there are single cases described in reports in the nonophthalmic literature (1 patient had a nail that penetrated the orbit without ocular penetration,3 whereas another describes a corneoscleral laceration with extruding ocular contents 2). In this article, we describe four
Originally received: January 16. 1996. Revision accepted: May 22, 1996. J Department of Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio. 2 Emory Eye Center, Atlanta. Presented in part at the Vitreous Society, London, England, August 1995, and at the American Academy of Ophthalmology Annual Meeting, Atlanta, OctINov 1995. Supported in part by departmental core grant P30EY06360 from the National Institutes of Health, Bethesda, Maryland, and by an unrestricted grant from Research to Prevent Blindness, Inc, New York, New York. Reprint requests to Bailey L. Lee, MD, University of Texas Health Science Center at San Antonio, Department of Ophthalmology, 7703 Floyd Curl Dr, San Antonio, TX 78284-6230.
consecutive patients with ocular nail gun injuries and their management.
Case Reports Case 1. A 41-year-old man was struck in the left eye with a nail while using a nail gun at work. The nail ricocheted from the piece of wood that he was nailing. The patient noticed an immediate drop in his visual acuity and saw his local ophthalmologist who referred him to the Emory Eye Center. On examination, his visual acuity was 20115 in the right eye and 20/40 in the left. There was no afferent pupillary defect. The anterior segment of the left eye showed a self-sealing corneal laceration paracentrally at approximately 10 o'clock with involvement of the underlying iris. The corneal wound was Seidel-negative, with no evidence of iris incarceration. There was no cellular reaction in either the aqueous or the vitreous. Gonioscopy showed the angle to be open without evidence of a foreign body. After the pupil was dilated, it was evident that the anterior capsule was penetrated underneath the iris with associated localized opacification of the lens. Results of funduscopic examination were unremarkable. Computed tomography scan of the orbit did not show any evidence of an intraocular foreign body. The patient was given oral and topical ciprofioxacin. Visual acuity decreased to 20/60 over the following week due to increasing lenticular opacification. The patient underwent phacoemulsification with posterior chamber lens implant without complications. Postoperatively, his visual acuity improved to 20/20. Case 2. A 21-year-old man was struck in the left eye by a nail fired from a nail gun. The nail ricocheted from the piece of wood that he was nailing and was protruding from the globe
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Volume 103, Number 9, September 1996
Figure 1. Case 2. A bent, barbed nail protrudes from the comeoscleral limbus, resulting from a ricochet nail gun injury. Arrow = the barbed portion of the nail.
when he presented to the Emory Eye Center (Fig 1). On examination, he was in moderate distress with a visual acuity of 201 40 in the right eye and counting fingers in the left. There was no afferent pupillary defect. A large, bent, barbed nail protruded from the corneosclerallimbus at the 4-o'clock meridian. There was limitation of motility secondary to the pain. He was taken to the operating room where careful examination of the anterior and posterior segment was completed. The nail entered the corneosclerallimbus and passed superiorly and posteriorly into the vitreous space, apparently b/ypassing the iris and lens. The nail was removed without difficulty, and the prolapsed vitreous was excised with sharp scissors. The scleral laceration then was closed with subsequent intravitreal injection of vancomycin (l mg) and amikacin (400 fJ,g). Results offunduscopic examination showed commotio retinae in the macula without any retinal tears or detachment. Postoperatively, he received intravenous cefazolin and topical prednisolone acetate, atropine, and gentamicin. Cultures of the nail did not show growth of any organisms. During the next week, a cataract developed that decreased his vision to counting fingers. Ultrasound showed that the retina was attached with a vitreous hemorrhage. Ten days after the initial injury, he underwent pars plana lensectomy and vitrectomy with prophylactic encircling scleral buckle with a 41 band. His visual acuity improved to 20/20, with aphakic contact lens correction. Case 3. A 25-year-old man was struck in the right eye with a nail. A nail gun was discharged accidentally while he held it on his knee. He stated that the nail projected from his eye, and he removed the nail himself. That day, he presented to the Veterans Administration Hospital in Decatur, Georgia, where a nasal-scleral laceration was repaired. He did well immediately postoperatively, but I month later he was referred to the Emory Eye Center because of persistent photopsia. On examination, visual acuity was 20/30 in the right eye and 20/20 in the left. There was no afferent pupillary defect. The anterior segment showed a clear cornea and lens, with trace cell and flare in the anterior chamber. Nylon sutures could be seen underneath the conjunctiva in the nasal-scleral area, approximately 5 mm posterior to the limbus at the 3-o'clock meridian. Results of funduscopic examination showed a transvitreal band that extended
1454
posteriorly from the entrance site nasally to underneath the inferotemporal arcade (Fig 2A). There was associated vitreous hemorrhage and vitreoretinal traction at the impact site with subretinal fluid. The patient underwent an encircling scleral buckle with a 41 band and pars plana vitrectomy with transection of the transvitreal band and membrane stripping. Postoperatively, the vitreoretinal traction was relieved (Figs 2B), and the patient's best-corrected visual acuity was 20/20. Case 4. A 22-year-old man reported a history of being struck by a board in the right eye while in a woodworking class. On initial examination, vision in the right eye was hand motions. Anterior segment examination showed a corneal laceration inferiorly at the 6-o'clock meridian to the limbus, with prolapse of iris and lens material through the wound. The anterior chamber was flat, and the eye was hypotonus. The patient was taken to the operating room where the corneal laceration was repaired with a lensectomy, anterior vitrectomy, and insertion of a posterior chamber lens. Postoperatively, the patient had persistent pain, especially with movement of the eye, and ocular inflammation, with vision decreased to bare light perception. On ultrasound examination, a very highly reflective nonmobile area of opacity was seen in the mid-vitreous cavity with a sonolucent
Figure 2, Case 3. A, impact site along the inferotemporal arcade with a pre-retinal hemorrhage and a transvitreal band extending to the entrance site. B, postoperative fundus of case 3 with the impact site along the posterior aspect of the scleral buckle.
Lee and Sternberg· Nail Gun Injuries Table 1. Summary of Ocular Nail Gun Injuries Case No. 1
2 3
4
Type of Injury
Mechanism
Corneal laceration Scleral laceration Perforation Perforation
Ricochet Ricochet Mid-air firing Over-penetration
Vision Outcome
20/20 20/20 20/20 Enucleation
trail extending through the posterior pole and a retinal detachment (Fig 3A), whereas radiologic studies showed a linear metallic foreign body that appeared to be a nail in the right globe extending into the maxillary sinus (Figs 3B and 3C). The patient later recalled that his head was directly behind a cabinet drawer that was being nailed with a nail gun when he was struck with a nail in the right eye. The patient was taken back to the operating room 12 days after the primary repair. During the pars plana vitrectomy, the retina clearly was necrotic and completely detached. The head of the nail was located in the macula. In view of the limited visual prognosis, an enucleation was performed. However, to complete the enucleation, the nail had to be removed because it had impaled the globe to the medial wall of the orbit. This was done with forceps through the cataract incision while the nail was simultaneously advanced out of the maxillary sinus through a Caldwell-Luc incision. The patient did well postoperatively. Results of histopathologic examination of the globe showed early siderosis bulbi without evidence of endophthalmitis.
Discussion
Figure 3. A, B-scan of case 4 shows highly reflective nonmobile mass (arrow) with marked shadowing consistent with an intraocular foreign body. B, radiograph of case 4 shows linear metallic foreign body in the orbit extending into the maxillary sinus. C, axial computed tomography scan shows metallic intraocular foreign body (arrow) of case 4.
Proper training of nail gun operators and use of safety designs should reduce the incidence of injury. Nail guns must be pressed firmly against a solid surface to be fired. However, this safety precaution commonly is circumvented by its user, leading to mid-air firing. The presence of a muzzle safety shield can decrease the likelihood of ricochet or shattering-type injury. Over-penetration type injuries can be reduced by the selection of the appropriate power load for a particular job. Also the operator and assistants should wear the appropriate protective wear such as safety glasses to help prevent injuries, as well as avoid being situated behind an area that is to be nailed. The configuration or shape of the nail can provide clues to the trajectory of the nail. Steel nails that are bent are due to a ricochet injury, whereas straight-nail injuries are most probably due to over-penetration of the material being nailed or accidental mid-air firing.3 Table 1 summarizes the type and mechanism of injury, as well as the final visual outcome. In case 2, the nail was bent and indicated a ricochet-type of injury, whereas in case 4 the nail on the radiologic studies was straight, suggesting a mid-air firing or over-penetration type of injury. When a nail gun injury occurs, removal of the nail may be complicated by the presence of metallic barbs on the nail (as in case 2). The nails that are loaded into the nail guns are held together either by a resin or copper
1455
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Volume 103, Number 9, September 1996
Figure 4. A strip of nails held to together by copper wires {arrow} that are loaded into a nail gun.
wire. The metallic barbs consists of fragments of the copper wire used to join the nails together that are preloaded into the nail gun (Fig 4). When the gun is fired, pieces of copper wire are sheared off the strip with the nail and remain attached to the nail by an adhesive resin. The metallic barb present is akin to those seen in fishhooks described in ocular penetrating injuries, and caution should be exercised in removing them to minimize tissue trauma. 9• IO Proper management of nail gun injuries is prompt recognition and attention, not only to the immediate concern of an intraocular foreign body or possible associated endophthalmitis, but also to the delayed sequelae of ocular trauma such as retinal detachment. The initial management in all patients with this type of injury should be the expeditious removal of the nail and repair of the laceration. In case 4, the presence of an intraocular foreign body was not suspected until several days after the primary repair. In case 2, the nail was removed during the primary repair, whereas in case 1 the nail penetrated the cornea with a self-sealing laceration. In case 3, the patient removed the nail himself. Previous authors have debated immediate versus delayed vitrectomy for ocular trauma, 11-15 but for instances of intraocular foreign bodies a vitrectomy usually is required for their removal in the primary repair. 16.17 The procedures of the three patients who underwent vitrectomy were performed from 10 days to 1 month after the initial injury. Whether immediate vitrectomy and removal of the nail in case 4 would have salvaged any useful vision is unlikely in view of the exit site in the macula. However, early recognition of the intraocular foreign body may have prevented siderosis bulbi. There also has been discussion in the literature on the benefits of prophylactic scleral buckling on traumatized eyes to reduce the incidence of retinal detachment. 13 •18 In cases 2 and 3 with scleral penetrating injuries, a scleral buckle was placed. In case 1 with only corneal penetration, a scleral buckle was not performed because there was no concern about an incarcerated retina or vitreous into the wound as with a scleral laceration. The visual prognosis after trauma has been correlated
1456
to various factors such as preoperative visual acuity, afferent pupillary defect, site of laceration, and type of injury. 15,18-20 In cases of perforating injuries, the mechanism of injury (either a missile versus a sharp object) and the state of the macula are important prognostic indicators of final visual acuity.21 A missile-type injury, such as that from a BB gun, requires great energy to create a blunt opening anteriorly.22-24 This results in tremendous contusive force transmitted to the globe. The mechanism of injury in a nail gun injury has both a missile and sharp object-type component. Three of the four patients had a good visual outcome. This may be because the sharp object type of injury causes less contusive forces, even though the nail is fired at high velocity with a component of a missile type of injury. In summary, we describe four patients with ocular injuries resulting from nail guns. Although three of the four patients had good visual outcome after surgical intervention, the best management plan would be prevention through proper education and the use of protective eye wear.
References 1. Lowery JC. Industrial nail gun injuries. Injury 1973;5:5962. 2. Lyons FR. Industrial nail gun injuries. Med J Aust 1983;2:483-6. 3. McCorkell SJ, Harley JD, Cummings D. Nail-gun injuries. Accident, homicide, or suicide? Am J Forensic Med Pathol 1986; 7: 192-5. 4. Edlich RF, Silloway KA, Rodeheaver T, et al. Industrial nail gun injuries. Compr Ther 1986; 12:4-46. 5. Thomas MD, Siu K. An unusual cranial injury caused by an industrial nail-gun. Med J Aust 1987; 147:602-3. 6. Barber FA. Penetrating knee injuries: the nail gun. Arthroscopy 1989;5:172-5. 7. Schor JS, Horowitz MD, Bringaze WL 3d, Thurer RJ. Industrial nail gun injuries. South Med J 1991;84:922-3. 8. Kenny NW, Kay PR, Haines JF. Nail gun injuries to the hand. J Hand Surg 1992 199217:577-8. 9. Mandelcorn MS, Crichton A. Fish hook removal from vitreous and retina. Case report. Arch Ophthalmol 1989; 107:493. 10. Aiello LP, Iwamoto M, Guyer DR. Penetrating ocular fishhook injuries. Surgical management and long-term visual outcome. Ophthalmology 1992; 99:862-6. II. Coleman DJ. Early vitrectomy in the management of the severely traumatized eye. Am J Ophthalmol 1982;93:543-51. 12. Ryan SJ, Allen AW. Pars plana vitrectomy in ocular trauma. Am J Ophthalmol 1979;88:483-91. 13. Brinton GS, Aaberg TM, Resser FH, et al. Surgical results in ocular trauma involving the posterior segment. Am J OphthalmolI982;93:271-8. 14. de Juan E, Sternberg P, Michels RG. Timing of vitrectomy after penetrating ocular injuries. Ophthalmology 1984; 91:1072-4. 15. Ahmadieh H, Soheilian M, Sajjadi H, et al. Vitrectomy in ocular trauma. Factors influencing final visual outcome. Retina 1993; 13: 107 -13. 16. Slusher MM. Intraretinal foreign bodies: management and observations. Retina 1990; lO(suppl):S50-4. 17. De Bustros S, Michels RG, Glaser BM. Evolving concepts
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Nail Gun Injuries 21. Martin DF, Meredith TA , Topping TM, et al. Perforating (through-and-through) injuries ofthe globe. Surgical results with vitrectomy. Arch Ophtha1moI1991;109:951-6. 22. Sternberg P, de Juan E, Green WR, et al. Ocular BB injuries. Ophthalmology 1984; 91: 1269-77. 23. Tillet CW, Rose HW Herget C. High-speed photographic study of perforating ocular injury by the BB. Am J Ophthalmol 1962;54:675-88. 24. DeLori F, Pomerantzeff 0, Cox MS. Deformation of the globe under high-speed impact: its relation to contusion injuries. Invest Ophthalmol Vis Sci 1969;8:290-301.
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