Tissue Breakdown and Exposure Associated With Orbital Hydroxyapatite Implants H e l m u t Buettner, M.D., a n d George B. Bartley, M.D.
Tissue breakdown and exposure of a hy droxyapatite implant were observed in eight patients: in four of six patients after eviscera tion and in four of 31 after enucleation. The reasons for evisceration were a blind, painful eye and endophthalmitis in two patients each. The reasons for enucleation were a choroidal melanoma in two patients and endophthalmi tis and irreparable traumatic damage in one patient each. The patients with endophthal mitis received the implant in a second sur gical procedure after intensive antibiotic treatment. Small tissue defects healed spon taneously, whereas large defects showed little tendency to heal by secondary intention. Tis sue breakdown over a hydroxyapatite implant may be related to delayed ingrowth of fibrovascular tissue, and possibly related to an inflammatory reaction incited by the hydroxy apatite. Careful case selection, facilitation of tissue penetration by drilling holes into the hydroxyapatite sphere, delayed fitting of the prosthesis, and vaulting of the posterior sur face of the initial prosthesis to reduce pres sure on the tissues covering the anterior pole of the implant may alleviate the problems of tissue breakdown and exposure. 1 HE PROBLEMS of tissue breakdown and expo sure associated with orbital implants after enu cleation or evisceration of the eye have led to the development of several orbital implants.
Accepted for publication March 20, 1992. From the Department of Ophthalmology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota. This study was supported in part by Research Grant EY06253 from the National Institutes of Health, an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York, and the Mayo Foundation. Reprint requests to Helmut Buettner, M.D., Mayo Clinic, 200 First St. S.W., Rochester, MN 55905.
The material and design of many of these im plants were chosen to reduce or eliminate such problems as well as to provide motility of the artificial eye. With these features in mind, a new integrated orbital implant, made of coral line hydroxyapatite, recently has been intro duced. 13 We observed tissue breakdown and exposure of the implant in eight of 37 patients who underwent enucleation or evisceration with placement of a hydroxyapatite sphere.
Subjects and Methods Between March 1990 and December 1991, 37 patients received a hydroxyapatite implant af ter enucleation (31 patients) or evisceration (six patients) of an eye. The implants were placed at the time of initial operation in 32 patients and during a second surgical procedure in five pa tients. Among these latter five patients, one received an implant ten weeks after enucleation and subsequent orbital irradiation because of optic nerve involvement by large cell lymphoma. One patient received a hydroxyapatite im plant to replace an exposed Allen implant placed 40 years earlier after enucleation of a severely traumatized eye. Three patients who had endophthalmitis received a hydroxyapatite implant between six and ten days after eviscera tion (two patients) or enucleation (one patient) and antibiotic therapy (systemically and topi cally applied). In the 32 patients who received an orbital hydroxyapatite implant at first opera tion, the indications for the procedure were a blind, painful, or phthisical eye in 14, a uveal melanoma in 16, and endophthalmitis in two. The hydroxyapatite implants (Integrated Or bital Implants, San Diego, California) were 16 to 22 mm in diameter. The most commonly used sizes were 18 and 20 mm. Postoperatively, the
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duration of follow-up ranged from two to 21 months (mean, eight months). Enucleation—After a 360-degree peritomy with Wescott's scissors, Tenon's capsule was bluntly separated between the recti muscles with Stevens' scissors. The insertions of the four recti muscles were isolated on a muscle hook, secured with a double-armed, locked, 6-0 polyglactin suture, and severed from the globe. The inferior and superior oblique muscles were retrieved with a muscle hook and dissected from the globe at their insertions. With gentle traction on the stump of the medial rectus muscle, a curved enucleation clamp was passed through the posterior aspect of Tenon's capsule nasally, placed over the optic nerve as far pos teriorly as possible, and closed. The nerve was then transsected with a curved enucleation scissors in front of the clamp. The globe was lifted from the orbit as residual tissue was cut. The socket was then packed with saline-soaked gauze, and the enucleation clamp was removed. Gauze packings were reapplied with moderate pressure until all bleeding had stopped. An appropriate-sized hydroxyapatite sphere was then prepared for implantation in the fol lowing manner. After the sphere was soaked in an antibiotic solution (1,000 U of bacitracin and 10 mg of neomycin sulfate per milliliter of Ringer's solution), it was wrapped in a whole human scleral shell. The shell had been pre pared from a donor eye. The eye, after removal of the cornea and optic nerve, had been evis cerated, freed from all episcleral tissue, and irradiated with 31,000 Gy from a Co 60 source while kept on dry ice. The sclera was then stored on dry ice until delivered to the opera ting room, where it was thawed in antibiotic solution. Two incisions were made opposite from each other starting at the corneal opening and ex tending to about the equator, and the hydroxy apatite sphere was then placed into the scleral shell. Excess sclera was excised, and the sclera was closed around the sphere with interrupted 5-0 polyglactin sutures. The sphere was left uncovered only at the corneal opening. At 10 to 12 mm from the pole opposite the corneal opening, four rectangular windows ( 2 x 3 mm) 90 degrees apart from each other, were cut into the sclera with a razor-blade knife and pointed suture scissors. In two cases the hydroxyapatite sphere was wrapped in donor human dura ma ter; this procedure was similar to the scleral
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wrapping, and the preservation method was the same as that used for the sclera. The wrapped implant was then placed into the orbit with the original corneal opening pointing posteriorly, and the four recti muscles were attached (with the previously placed mus cle sutures) to the anterior corners of the rec tangular windows in the scleral or dural wrap ping. Tenon's capsule was closed (with avoidance of undue tension) with running, in terlocking, 4-0 chromic gut suture. Before com pletion of this closure, the implant and orbit were irrigated with the same antibiotic solution that was used to soak the hydroxyapatite sphere. The conjunctiva was closed with run ning, interlocking, 6-0 plain gut suture. Antibi otic ointment was applied, and a cul-de-sac conformer was placed for three to five days. The patient was instructed to apply antibiotic oint ment twice a day for two weeks. Evisceration—The sclera was incised 360 de grees just posterior to the corneoscleral limbus. With an evisceration spoon, the uvea was sepa rated from the sclera in the suprachoroidal plane, and the ocular contents were removed. The interior of the scleral shell was then scrubbed with gauze to remove all tissue rem nants. After a scleral window was cut in each quadrant between the recti muscles and two opposed relaxing incisions were made anterior ly, a hydroxyapatite sphere, infiltrated with a solution of bacitracin and neomycin, was placed into the scleral shell, which was then closed with interrupted 5-0 polyglactin su tures. Tenon's capsule and the conjunctiva were closed as described. Implants placed at a second procedure—In the three patients who received a hydroxyapatite implant after enucleation of the eye or removal of a previously placed implant, the recti mus cles were isolated, freed from scar tissue, and sutured to the covering of the implant as de scribed above. In the two eyes eviscerated for endophthalmitis, a hydroxyapatite sphere was placed into the scleral shell after removal of the antibiotic-containing gauze packing. The scle ra, Tenon's capsule, and conjunctiva were closed as described. Fitting of prosthesis—The ocular prosthesis was fitted five to six weeks after placement of the implant. When desired, a motility peg was placed after another six to eight months to allow for adequate vascularization of the im plant. To date, we have placed motility pegs in
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only four patients. In the other patients, motility of the prosthesis was satisfactory without the peg, the patients did not want an additional operation, or the socket was not ready for peg placement.
Results In four of the eight patients the hydroxyapa tite sphere had been placed into the scleral shell after evisceration of the globe, and in the other four patients a hydroxyapatite sphere, wrapped in preserved donor sclera, had been implanted into the socket after enucleation of the eye (Table). In two of the four patients who had undergone evisceration, endophthalmitis had originally been present. Of the four patients in
whom tissue breakdown and exposure devel oped after enucleation, one had had an infected eye. The tissue defects were noted in the pa tients with endophthalmitis at three, five, and six weeks after placement of the implant, whereas in the patients without intraocular infection they developed at two, four, seven, and 16 weeks after implantation of a hydroxy apatite sphere. In two patients, the tissue defect was noted at four and ten weeks after fitting with the prosthetic eye. In all patients, the defects involved both the central socket conjunctiva and the scleral cover of the hydroxyapatite sphere (either the pa tient's own sclera after evisceration or the pre served donor sclera after enucleation) (Figs. 1 and 2). In five patients the defect healed sponta neously, in two of them while they were wear ing the prosthesis. In one patient the tissue
TABLE TISSUE BREAKDOWN AND EXPOSURE ASSOCIATED WITH HYDROXYAPATITE IMPLANTS CASE NO, AGE (YRS), GENDER
TIME WHEN DIAGNOSIS
1, 13, M
Blind, painful eye
2, 36, F
Blind, painful eye
3, 65, F
5, 54, F
Herpetic/bacterial keratitis; two failed corneal grafts; endoph thalmitis Blind, painful eye after rheumatoid corneal melt; endophthalmitis Choroidal melanoma
6, 65, F 7, 23, M
4, 73, M
8, 18, M
PROCEDURE
TISSUE
DEFECT WAS
DEFECT
NOTED
MANAGEMENT
Evisceration; Central 2-mm 18-mm implant defect
RESULT
16 wks after Vaulting of poster evisceration; ior prosthesis 10 wks after surface prosthetic fitting Evisceration; 7 wks after Vaulting of poster Two central evisceration 20-mm implant 1 -mm defects ior prosthesis surface Evisceration; 8 wks after Vaulting of poster Central 3.5 x 16-mm implant 2.5-mm defect evisceration ior prosthesis 10 days later surface
Defect healed spontaneously
Evisceration; 18-mm implant 6 days later
Central 10 x 15-mm defect
6 wks after evisceration
Defect stable 7 mo postoperatively
Enucleation; 18-mm implant
Central 5 x 5-mm defect
Choroidal melanoma
Enucleation; 20-mm implant
Central 1 x 2-mm defect
4 mo after enucleation; 4 wks after prosthetic fitting 4 wks after enucleation
Dermal patch graft melted within 3 days; prosthetic fitting Scleral patch graft; vaulting of poster ior prosthesis surface
Intraocular foreign body; endoph thalmitis Trauma; disorga nized globe
Enucleation; 16-mm implant
Central 2 x 4-mm defect
3 wks after enucleation
Defect healed 4 mo after prosthesis fitting Defect healed 7 wks after enucleation
Enucleation; 20-mm implant
Central 1 x 3-mm defect
2 wks after enucleation
Vaulting of poster ior prosthesis surface Topically applied antibiotic ointment Suturing of defect, failed
Defect stable 8 mo postoperatively Defect stable 8 mo postoperatively
Implant well covered 7 mo postopera tively
Defect healed within 3 wks
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Fig. 1 (Buettner and Bartley). Case 3. Central tissue dehiscence (2.5 x 3.5 mm) exposing hydroxyapatite implant four months after evisceration of an eye with endophthalmitis. defect was covered with a scleral patch graft. In two patients who were wearing a prosthesis in the absence of any signs of a clinical infection, granulation tissue was gradually closing the defect eight and seven months, respectively, after placement of the implant. None of the patients have required removal of the hydroxy apatite implant, and none of the exposed im plants had clinical signs of infection.
Discussion Tissue breakdown, exposure, and extrusion associated with orbital implants after eviscera tion or enucleation of an eye have been prob lems ever since introduction of the orbital im plant by Mules. 4 Migration of the implant and poor motility of the prosthetic eye were other problems that led to the design of several orbi tal implants during the past century. 6 A recent innovation is the hydroxyapatite implant, which combines biocompatibility (through in tegration of fibrovascular orbital tissue) with excellent motility (by attachment of the mus cles to the implant and later coupling with the ocular prosthesis using a special peg). No com plications have been reported with this new implant. 13 We, however, observed tissue breakdown and exposure of the hydroxyapatite implant after both evisceration and enucleation with the technique described by Perry 12 and Dutton. 3 Exposure was more common after evisceration (four of six patients) than after enucleation
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Fig. 2 (Buettner and Bartley). Case 4. Central tissue defect (10 x 15 mm) exposing the anterior pole of the hydroxyapatite implant two months after eviscera tion of an eye with endophthalmitis (which occurred after corneal melting caused by rheumatoid disease). Note absence of fibrovascular granulation tissue. (four of 31 patients). Endophthalmitis, present in one patient who had enucleation (Case 7) and two patients who had evisceration (Cases 3 and 4), may have persisted in the sclera or periocular tissues or may have made these tis sues more susceptible to tissue breakdown. However, we believed that the intensive antibi otic treatment used before placement of the implant had eradicated the infection. Addition ally, there was no clinical evidence for infection when tissue breakdown occurred. In one pa tient (Case 4), rheumatoid disease had caused corneal melting and eventual endophthalmitis. Conceivably, the rheumatoid disorder also af fected the sclera and thus contributed to tissue breakdown and exposure of the implant. We do not believe that our preservation meth od of irradiation and deep freezing makes the donor sclera more susceptible to breakdown than preservation in absolute alcohol, as used by Dutton, 3 or preservation by freezing fresh donor sclera, as practiced by Perry.1,2 The breakdown of the patient's own sclera after evisceration and implantation of a hydroxyapa tite sphere, particularly in the absence of en dophthalmitis, suggests that breakdown and exposure are caused by factors other than the method used to preserve the tissue in which the implant is wrapped. In this series, the tissue defects associated with hydroxyapatite implants healed spontane ously in five of the eight patients, in some even while they were wearing a specially adapted prosthesis. All of these defects were relatively
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small. The t h r e e largest defects s h o w e d m u c h less t e n d e n c y for s p o n t a n e o u s h e a l i n g . In t h e s e cases, surgical c l o s u r e s h o u l d b e c o n s i d e r e d early, n o t only to p r e v e n t p o s s i b l e infection of the i m p l a n t (for w h i c h t h e r e w a s n o clinical e v i d e n c e in any of o u r cases) b u t also to s p e e d u p r e h a b i l i t a t i o n of t h e p a t i e n t . In our s t u d y , w h e n a large p o r t i o n of the a n t e r i o r p o l e of the h y d r o x y a p a t i t e s p h e r e h a d b e e n e x p o s e d , fibrovascular t i s s u e i n g r o w t h into the a n t e r i o r p o r t i o n of the p o r o u s i m p l a n t m a t e r i a l w a s n o t o b s e r v e d , a l t h o u g h fibrovas cular i n g r o w t h into a h y d r o x y a p a t i t e i m p l a n t , m a i n l y at the site of t h e scleral w i n d o w s , h a s b e e n d e m o n s t r a t e d h i s t o p a t h o l o g i c a l l y as early as 19 days a n d four w e e k s after p l a c e m e n t i n t o t h e orbit. 6,7 C o n c e r n a b o u t t i m e l y t i s s u e in g r o w t h a p p a r e n t l y p r o m p t e d D u t t o n 3 t o drill 1-mm h o l e s into t h e h y d r o x y a p a t i t e s p h e r e t h r o u g h the scleral w i n d o w s as well as t h e corneal defect of the scleral w r a p p i n g to facili tate p e n e t r a t i o n b y fibrovascular t i s s u e . Lack of i n g r o w t h m a y b e a factor in t i s s u e b r e a k d o w n a n d e x p o s u r e . It p a r t i c u l a r l y m a y have b e e n a factor in the cases in w h i c h d e h i s c e n c e d i d n o t d e v e l o p u n t i l after t h e p a t i e n t h a d b e e n w e a r ing a p r o s t h e s i s . The d o n o r sclera is a p p a r e n t l y r e s o r b e d a n d T e n o n ' s c a p s u l e a n d the c o n j u n c tiva are e r o d e d if fibrovascular tissue h a s n o t f o r m e d w i t h i n the h y d r o x y a p a t i t e s p h e r e by the t i m e the ocular p r o s t h e s i s is fitted. R e s o r p t i o n of t h e scleral t i s s u e c o v e r i n g t h e h y d r o x y a p a t i t e sphere may be accelerated by a foreign-body giant cell i n f l a m m a t o r y r e a c t i o n , w h i c h h a s b e e n n o t e d in t w o i m p l a n t s r e m o v e d 19 days a n d four w e e k s after orbital placement 6 ' 7 a n d in t h e buccal soft tissue of b e a g l e s after i m p l a n t a tion of h y d r o x y a p a t i t e p a r t i c l e s . 8 It is conceiv able t h a t this i n f l a m m a t o r y r e a c t i o n is incited b y c o m p o n e n t s of the c h e m i c a l l y p r o c e s s e d n a t u r a l coral of w h i c h the h y d r o x y a p a t i t e i m p l a n t s are m a d e . 7 C o n t a c t of t h e p r o s t h e s i s w i t h t h e conjunctiva m a y also c o n t r i b u t e to t i s s u e e r o s i o n over t h e h y d r o x y a p a t i t e s p h e r e if fibro v a s c u l a r i n g r o w t h is d e l a y e d . This t h e o r y is s u p p o r t e d b y our o b s e r v a t i o n of t h e h e a l i n g of small tissue defects w h e n c o n t a c t w a s r e d u c e d b y v a u l t i n g of the p o s t e r i o r surface of the p r o s thesis. Tissue e r o s i o n over i m p l a n t e d h y d r o x y a p a t i t e h a s n o t b e e n r e p o r t e d w i t h orbital implants.13'910 When challenged by bacterial infection, s u b p e r i o s t e a l m a n d i b u l a r h y d r o x y a p a t i t e i m p l a n t s in r a b b i t s did n o t b e c o m e exposed, despite a persistent chronic inflamma
tory r e a c t i o n s u r r o u n d i n g the implant. 1 0 In four of 56 p a t i e n t s w h o received s u b p e r i o s t e a l injec t i o n s of p a r t i c u l a t e h y d r o x y a p a t i t e to a u g m e n t deficient alveolar r i d g e s , t i s s u e d e h i s c e n c e s w i t h m i n o r loss of h y d r o x y a p a t i t e p a r t i c l e s w e r e observed. 1 1 In all four cases the d e h i s cences h e a l e d s p o n t a n e o u s l y w i t h o u t infection. A l t h o u g h t h e p o s i t i o n a n d m o t i l i t y of the h y d r o x y a p a t i t e i m p l a n t s w e r e satisfactory in our s t u d y , the d e v e l o p m e n t of tissue defects a n d e x p o s u r e of a c o n s i d e r a b l e n u m b e r of im p l a n t s are of c o n c e r n . We h o p e t h e s e p r o b l e m s can b e a l l e v i a t e d by careful case selection, facilitation of t i s s u e p e n e t r a t i o n b y drilling h o l e s into the i m p l a n t , late fitting of t h e ocular p r o s t h e s i s , a n d v a u l t i n g t h e p o s t e r i o r surface of the initial p r o s t h e s i s to r e d u c e p r e s s u r e on the tissues over the a n t e r i o r p o l e of t h e i m p l a n t .
References 1. Perry, A. C : Integrated orbital implants. Adv. Ophthalmic Plast. Reconstr. Surg. 8:75, 1988. : Advances in enucleation. Ophthalmol. 2. Clin. North Am. 4:173, 1991. 3. Dutton, J. J.: Coralline hydroxyapatite as an ocular implant. Ophthalmology 98:370, 1991. 4. Mules, P. H.: Evisceration of the globe with artificial vitreous. Trans. Ophthalmol. Soc. U.K. 5:200, 1885. 5. Gougelmann, H. P.: The evolution of the ocular motility implant. Int. Ophthalmol. Clin. 10:689, 1970. 6. Shields, C. L., Shields, J. A., Eagle, R. C , Jr., and De Potter, P.: Histopathologic evidence of fibro vascular ingrowth four weeks after placement of the hydroxyapatite orbital implant. Am. J. Ophthalmol. 111:363, 1991. 7. Rosner, M., Edward, D. P., and Tso, M. O. M.: Foreign-body giant-cell reaction to the hydroxyapa tite orbital implant. Arch. Ophthalmol. 110:173, 1992. 8. Misiek, D. J., Kent, J. N., and Carr, R. F.: Soft tissue responses to hydroxylapatite particles of dif ferent shapes. J. Oral Maxillofac. Surg. 42:150, 1984. 9. Zide, M. F.: Late posttraumatic enophthalmos corrected by dense hydroxylapatite blocks. J. Oral Maxillofac. Surg. 44:804, 1986. 10. Reznick, J. B., and Gilmore, W. C : Host re sponse to infection of a subperiosteal hydroxylapa tite implant. Oral Surg. Oral Med. Oral Pathol. 67:665, 1989. 11. Kent, J. N., Quinn, J. H., Zide, M. F., Guerra, L. R., and Boyne, P. J.: Alveolar ridge augmentation using nonresorbable hydroxylapatite with or without autogenous cancellous bone. J. Oral Maxillofac. Surg. 41:629, 1983.
Tissue breakdown and exposure of a hy droxyapatite implant were observed in eight patients: in four of six patients after eviscera tion and in four of 31 after enucleation. The reasons for evisceration were a blind, painful eye and endophthalmitis in two patients each. The reasons for enucleation were a choroidal melanoma in two patients and endophthalmi tis and irreparable traumatic damage in one patient each. The patients with endophthal mitis received the implant in a second sur gical procedure after intensive antibiotic treatment. Small tissue defects healed spon taneously, whereas large defects showed little tendency to heal by secondary intention. Tis sue breakdown over a hydroxyapatite implant may be related to delayed ingrowth of fibrovascular tissue, and possibly related to an inflammatory reaction incited by the hydroxy apatite. Careful case selection, facilitation of tissue penetration by drilling holes into the hydroxyapatite sphere, delayed fitting of the prosthesis, and vaulting of the posterior sur face of the initial prosthesis to reduce pres sure on the tissues covering the anterior pole of the implant may alleviate the problems of tissue breakdown and exposure. 1 HE PROBLEMS of tissue breakdown and expo sure associated with orbital implants after enu cleation or evisceration of the eye have led to the development of several orbital implants.
Accepted for publication March 20, 1992. From the Department of Ophthalmology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota. This study was supported in part by Research Grant EY06253 from the National Institutes of Health, an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York, and the Mayo Foundation. Reprint requests to Helmut Buettner, M.D., Mayo Clinic, 200 First St. S.W., Rochester, MN 55905.
The material and design of many of these im plants were chosen to reduce or eliminate such problems as well as to provide motility of the artificial eye. With these features in mind, a new integrated orbital implant, made of coral line hydroxyapatite, recently has been intro duced. 13 We observed tissue breakdown and exposure of the implant in eight of 37 patients who underwent enucleation or evisceration with placement of a hydroxyapatite sphere.
Subjects and Methods Between March 1990 and December 1991, 37 patients received a hydroxyapatite implant af ter enucleation (31 patients) or evisceration (six patients) of an eye. The implants were placed at the time of initial operation in 32 patients and during a second surgical procedure in five pa tients. Among these latter five patients, one received an implant ten weeks after enucleation and subsequent orbital irradiation because of optic nerve involvement by large cell lymphoma. One patient received a hydroxyapatite im plant to replace an exposed Allen implant placed 40 years earlier after enucleation of a severely traumatized eye. Three patients who had endophthalmitis received a hydroxyapatite implant between six and ten days after eviscera tion (two patients) or enucleation (one patient) and antibiotic therapy (systemically and topi cally applied). In the 32 patients who received an orbital hydroxyapatite implant at first opera tion, the indications for the procedure were a blind, painful, or phthisical eye in 14, a uveal melanoma in 16, and endophthalmitis in two. The hydroxyapatite implants (Integrated Or bital Implants, San Diego, California) were 16 to 22 mm in diameter. The most commonly used sizes were 18 and 20 mm. Postoperatively, the
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duration of follow-up ranged from two to 21 months (mean, eight months). Enucleation—After a 360-degree peritomy with Wescott's scissors, Tenon's capsule was bluntly separated between the recti muscles with Stevens' scissors. The insertions of the four recti muscles were isolated on a muscle hook, secured with a double-armed, locked, 6-0 polyglactin suture, and severed from the globe. The inferior and superior oblique muscles were retrieved with a muscle hook and dissected from the globe at their insertions. With gentle traction on the stump of the medial rectus muscle, a curved enucleation clamp was passed through the posterior aspect of Tenon's capsule nasally, placed over the optic nerve as far pos teriorly as possible, and closed. The nerve was then transsected with a curved enucleation scissors in front of the clamp. The globe was lifted from the orbit as residual tissue was cut. The socket was then packed with saline-soaked gauze, and the enucleation clamp was removed. Gauze packings were reapplied with moderate pressure until all bleeding had stopped. An appropriate-sized hydroxyapatite sphere was then prepared for implantation in the fol lowing manner. After the sphere was soaked in an antibiotic solution (1,000 U of bacitracin and 10 mg of neomycin sulfate per milliliter of Ringer's solution), it was wrapped in a whole human scleral shell. The shell had been pre pared from a donor eye. The eye, after removal of the cornea and optic nerve, had been evis cerated, freed from all episcleral tissue, and irradiated with 31,000 Gy from a Co 60 source while kept on dry ice. The sclera was then stored on dry ice until delivered to the opera ting room, where it was thawed in antibiotic solution. Two incisions were made opposite from each other starting at the corneal opening and ex tending to about the equator, and the hydroxy apatite sphere was then placed into the scleral shell. Excess sclera was excised, and the sclera was closed around the sphere with interrupted 5-0 polyglactin sutures. The sphere was left uncovered only at the corneal opening. At 10 to 12 mm from the pole opposite the corneal opening, four rectangular windows ( 2 x 3 mm) 90 degrees apart from each other, were cut into the sclera with a razor-blade knife and pointed suture scissors. In two cases the hydroxyapatite sphere was wrapped in donor human dura ma ter; this procedure was similar to the scleral
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wrapping, and the preservation method was the same as that used for the sclera. The wrapped implant was then placed into the orbit with the original corneal opening pointing posteriorly, and the four recti muscles were attached (with the previously placed mus cle sutures) to the anterior corners of the rec tangular windows in the scleral or dural wrap ping. Tenon's capsule was closed (with avoidance of undue tension) with running, in terlocking, 4-0 chromic gut suture. Before com pletion of this closure, the implant and orbit were irrigated with the same antibiotic solution that was used to soak the hydroxyapatite sphere. The conjunctiva was closed with run ning, interlocking, 6-0 plain gut suture. Antibi otic ointment was applied, and a cul-de-sac conformer was placed for three to five days. The patient was instructed to apply antibiotic oint ment twice a day for two weeks. Evisceration—The sclera was incised 360 de grees just posterior to the corneoscleral limbus. With an evisceration spoon, the uvea was sepa rated from the sclera in the suprachoroidal plane, and the ocular contents were removed. The interior of the scleral shell was then scrubbed with gauze to remove all tissue rem nants. After a scleral window was cut in each quadrant between the recti muscles and two opposed relaxing incisions were made anterior ly, a hydroxyapatite sphere, infiltrated with a solution of bacitracin and neomycin, was placed into the scleral shell, which was then closed with interrupted 5-0 polyglactin su tures. Tenon's capsule and the conjunctiva were closed as described. Implants placed at a second procedure—In the three patients who received a hydroxyapatite implant after enucleation of the eye or removal of a previously placed implant, the recti mus cles were isolated, freed from scar tissue, and sutured to the covering of the implant as de scribed above. In the two eyes eviscerated for endophthalmitis, a hydroxyapatite sphere was placed into the scleral shell after removal of the antibiotic-containing gauze packing. The scle ra, Tenon's capsule, and conjunctiva were closed as described. Fitting of prosthesis—The ocular prosthesis was fitted five to six weeks after placement of the implant. When desired, a motility peg was placed after another six to eight months to allow for adequate vascularization of the im plant. To date, we have placed motility pegs in
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only four patients. In the other patients, motility of the prosthesis was satisfactory without the peg, the patients did not want an additional operation, or the socket was not ready for peg placement.
Results In four of the eight patients the hydroxyapa tite sphere had been placed into the scleral shell after evisceration of the globe, and in the other four patients a hydroxyapatite sphere, wrapped in preserved donor sclera, had been implanted into the socket after enucleation of the eye (Table). In two of the four patients who had undergone evisceration, endophthalmitis had originally been present. Of the four patients in
whom tissue breakdown and exposure devel oped after enucleation, one had had an infected eye. The tissue defects were noted in the pa tients with endophthalmitis at three, five, and six weeks after placement of the implant, whereas in the patients without intraocular infection they developed at two, four, seven, and 16 weeks after implantation of a hydroxy apatite sphere. In two patients, the tissue defect was noted at four and ten weeks after fitting with the prosthetic eye. In all patients, the defects involved both the central socket conjunctiva and the scleral cover of the hydroxyapatite sphere (either the pa tient's own sclera after evisceration or the pre served donor sclera after enucleation) (Figs. 1 and 2). In five patients the defect healed sponta neously, in two of them while they were wear ing the prosthesis. In one patient the tissue
TABLE TISSUE BREAKDOWN AND EXPOSURE ASSOCIATED WITH HYDROXYAPATITE IMPLANTS CASE NO, AGE (YRS), GENDER
TIME WHEN DIAGNOSIS
1, 13, M
Blind, painful eye
2, 36, F
Blind, painful eye
3, 65, F
5, 54, F
Herpetic/bacterial keratitis; two failed corneal grafts; endoph thalmitis Blind, painful eye after rheumatoid corneal melt; endophthalmitis Choroidal melanoma
6, 65, F 7, 23, M
4, 73, M
8, 18, M
PROCEDURE
TISSUE
DEFECT WAS
DEFECT
NOTED
MANAGEMENT
Evisceration; Central 2-mm 18-mm implant defect
RESULT
16 wks after Vaulting of poster evisceration; ior prosthesis 10 wks after surface prosthetic fitting Evisceration; 7 wks after Vaulting of poster Two central evisceration 20-mm implant 1 -mm defects ior prosthesis surface Evisceration; 8 wks after Vaulting of poster Central 3.5 x 16-mm implant 2.5-mm defect evisceration ior prosthesis 10 days later surface
Defect healed spontaneously
Evisceration; 18-mm implant 6 days later
Central 10 x 15-mm defect
6 wks after evisceration
Defect stable 7 mo postoperatively
Enucleation; 18-mm implant
Central 5 x 5-mm defect
Choroidal melanoma
Enucleation; 20-mm implant
Central 1 x 2-mm defect
4 mo after enucleation; 4 wks after prosthetic fitting 4 wks after enucleation
Dermal patch graft melted within 3 days; prosthetic fitting Scleral patch graft; vaulting of poster ior prosthesis surface
Intraocular foreign body; endoph thalmitis Trauma; disorga nized globe
Enucleation; 16-mm implant
Central 2 x 4-mm defect
3 wks after enucleation
Defect healed 4 mo after prosthesis fitting Defect healed 7 wks after enucleation
Enucleation; 20-mm implant
Central 1 x 3-mm defect
2 wks after enucleation
Vaulting of poster ior prosthesis surface Topically applied antibiotic ointment Suturing of defect, failed
Defect stable 8 mo postoperatively Defect stable 8 mo postoperatively
Implant well covered 7 mo postopera tively
Defect healed within 3 wks
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Fig. 1 (Buettner and Bartley). Case 3. Central tissue dehiscence (2.5 x 3.5 mm) exposing hydroxyapatite implant four months after evisceration of an eye with endophthalmitis. defect was covered with a scleral patch graft. In two patients who were wearing a prosthesis in the absence of any signs of a clinical infection, granulation tissue was gradually closing the defect eight and seven months, respectively, after placement of the implant. None of the patients have required removal of the hydroxy apatite implant, and none of the exposed im plants had clinical signs of infection.
Discussion Tissue breakdown, exposure, and extrusion associated with orbital implants after eviscera tion or enucleation of an eye have been prob lems ever since introduction of the orbital im plant by Mules. 4 Migration of the implant and poor motility of the prosthetic eye were other problems that led to the design of several orbi tal implants during the past century. 6 A recent innovation is the hydroxyapatite implant, which combines biocompatibility (through in tegration of fibrovascular orbital tissue) with excellent motility (by attachment of the mus cles to the implant and later coupling with the ocular prosthesis using a special peg). No com plications have been reported with this new implant. 13 We, however, observed tissue breakdown and exposure of the hydroxyapatite implant after both evisceration and enucleation with the technique described by Perry 12 and Dutton. 3 Exposure was more common after evisceration (four of six patients) than after enucleation
June, 1992
Fig. 2 (Buettner and Bartley). Case 4. Central tissue defect (10 x 15 mm) exposing the anterior pole of the hydroxyapatite implant two months after eviscera tion of an eye with endophthalmitis (which occurred after corneal melting caused by rheumatoid disease). Note absence of fibrovascular granulation tissue. (four of 31 patients). Endophthalmitis, present in one patient who had enucleation (Case 7) and two patients who had evisceration (Cases 3 and 4), may have persisted in the sclera or periocular tissues or may have made these tis sues more susceptible to tissue breakdown. However, we believed that the intensive antibi otic treatment used before placement of the implant had eradicated the infection. Addition ally, there was no clinical evidence for infection when tissue breakdown occurred. In one pa tient (Case 4), rheumatoid disease had caused corneal melting and eventual endophthalmitis. Conceivably, the rheumatoid disorder also af fected the sclera and thus contributed to tissue breakdown and exposure of the implant. We do not believe that our preservation meth od of irradiation and deep freezing makes the donor sclera more susceptible to breakdown than preservation in absolute alcohol, as used by Dutton, 3 or preservation by freezing fresh donor sclera, as practiced by Perry.1,2 The breakdown of the patient's own sclera after evisceration and implantation of a hydroxyapa tite sphere, particularly in the absence of en dophthalmitis, suggests that breakdown and exposure are caused by factors other than the method used to preserve the tissue in which the implant is wrapped. In this series, the tissue defects associated with hydroxyapatite implants healed spontane ously in five of the eight patients, in some even while they were wearing a specially adapted prosthesis. All of these defects were relatively
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small. The t h r e e largest defects s h o w e d m u c h less t e n d e n c y for s p o n t a n e o u s h e a l i n g . In t h e s e cases, surgical c l o s u r e s h o u l d b e c o n s i d e r e d early, n o t only to p r e v e n t p o s s i b l e infection of the i m p l a n t (for w h i c h t h e r e w a s n o clinical e v i d e n c e in any of o u r cases) b u t also to s p e e d u p r e h a b i l i t a t i o n of t h e p a t i e n t . In our s t u d y , w h e n a large p o r t i o n of the a n t e r i o r p o l e of the h y d r o x y a p a t i t e s p h e r e h a d b e e n e x p o s e d , fibrovascular t i s s u e i n g r o w t h into the a n t e r i o r p o r t i o n of the p o r o u s i m p l a n t m a t e r i a l w a s n o t o b s e r v e d , a l t h o u g h fibrovas cular i n g r o w t h into a h y d r o x y a p a t i t e i m p l a n t , m a i n l y at the site of t h e scleral w i n d o w s , h a s b e e n d e m o n s t r a t e d h i s t o p a t h o l o g i c a l l y as early as 19 days a n d four w e e k s after p l a c e m e n t i n t o t h e orbit. 6,7 C o n c e r n a b o u t t i m e l y t i s s u e in g r o w t h a p p a r e n t l y p r o m p t e d D u t t o n 3 t o drill 1-mm h o l e s into t h e h y d r o x y a p a t i t e s p h e r e t h r o u g h the scleral w i n d o w s as well as t h e corneal defect of the scleral w r a p p i n g to facili tate p e n e t r a t i o n b y fibrovascular t i s s u e . Lack of i n g r o w t h m a y b e a factor in t i s s u e b r e a k d o w n a n d e x p o s u r e . It p a r t i c u l a r l y m a y have b e e n a factor in the cases in w h i c h d e h i s c e n c e d i d n o t d e v e l o p u n t i l after t h e p a t i e n t h a d b e e n w e a r ing a p r o s t h e s i s . The d o n o r sclera is a p p a r e n t l y r e s o r b e d a n d T e n o n ' s c a p s u l e a n d the c o n j u n c tiva are e r o d e d if fibrovascular tissue h a s n o t f o r m e d w i t h i n the h y d r o x y a p a t i t e s p h e r e by the t i m e the ocular p r o s t h e s i s is fitted. R e s o r p t i o n of t h e scleral t i s s u e c o v e r i n g t h e h y d r o x y a p a t i t e sphere may be accelerated by a foreign-body giant cell i n f l a m m a t o r y r e a c t i o n , w h i c h h a s b e e n n o t e d in t w o i m p l a n t s r e m o v e d 19 days a n d four w e e k s after orbital placement 6 ' 7 a n d in t h e buccal soft tissue of b e a g l e s after i m p l a n t a tion of h y d r o x y a p a t i t e p a r t i c l e s . 8 It is conceiv able t h a t this i n f l a m m a t o r y r e a c t i o n is incited b y c o m p o n e n t s of the c h e m i c a l l y p r o c e s s e d n a t u r a l coral of w h i c h the h y d r o x y a p a t i t e i m p l a n t s are m a d e . 7 C o n t a c t of t h e p r o s t h e s i s w i t h t h e conjunctiva m a y also c o n t r i b u t e to t i s s u e e r o s i o n over t h e h y d r o x y a p a t i t e s p h e r e if fibro v a s c u l a r i n g r o w t h is d e l a y e d . This t h e o r y is s u p p o r t e d b y our o b s e r v a t i o n of t h e h e a l i n g of small tissue defects w h e n c o n t a c t w a s r e d u c e d b y v a u l t i n g of the p o s t e r i o r surface of the p r o s thesis. Tissue e r o s i o n over i m p l a n t e d h y d r o x y a p a t i t e h a s n o t b e e n r e p o r t e d w i t h orbital implants.13'910 When challenged by bacterial infection, s u b p e r i o s t e a l m a n d i b u l a r h y d r o x y a p a t i t e i m p l a n t s in r a b b i t s did n o t b e c o m e exposed, despite a persistent chronic inflamma
tory r e a c t i o n s u r r o u n d i n g the implant. 1 0 In four of 56 p a t i e n t s w h o received s u b p e r i o s t e a l injec t i o n s of p a r t i c u l a t e h y d r o x y a p a t i t e to a u g m e n t deficient alveolar r i d g e s , t i s s u e d e h i s c e n c e s w i t h m i n o r loss of h y d r o x y a p a t i t e p a r t i c l e s w e r e observed. 1 1 In all four cases the d e h i s cences h e a l e d s p o n t a n e o u s l y w i t h o u t infection. A l t h o u g h t h e p o s i t i o n a n d m o t i l i t y of the h y d r o x y a p a t i t e i m p l a n t s w e r e satisfactory in our s t u d y , the d e v e l o p m e n t of tissue defects a n d e x p o s u r e of a c o n s i d e r a b l e n u m b e r of im p l a n t s are of c o n c e r n . We h o p e t h e s e p r o b l e m s can b e a l l e v i a t e d by careful case selection, facilitation of t i s s u e p e n e t r a t i o n b y drilling h o l e s into the i m p l a n t , late fitting of t h e ocular p r o s t h e s i s , a n d v a u l t i n g t h e p o s t e r i o r surface of the initial p r o s t h e s i s to r e d u c e p r e s s u r e on the tissues over the a n t e r i o r p o l e of t h e i m p l a n t .
References 1. Perry, A. C : Integrated orbital implants. Adv. Ophthalmic Plast. Reconstr. Surg. 8:75, 1988. : Advances in enucleation. Ophthalmol. 2. Clin. North Am. 4:173, 1991. 3. Dutton, J. J.: Coralline hydroxyapatite as an ocular implant. Ophthalmology 98:370, 1991. 4. Mules, P. H.: Evisceration of the globe with artificial vitreous. Trans. Ophthalmol. Soc. U.K. 5:200, 1885. 5. Gougelmann, H. P.: The evolution of the ocular motility implant. Int. Ophthalmol. Clin. 10:689, 1970. 6. Shields, C. L., Shields, J. A., Eagle, R. C , Jr., and De Potter, P.: Histopathologic evidence of fibro vascular ingrowth four weeks after placement of the hydroxyapatite orbital implant. Am. J. Ophthalmol. 111:363, 1991. 7. Rosner, M., Edward, D. P., and Tso, M. O. M.: Foreign-body giant-cell reaction to the hydroxyapa tite orbital implant. Arch. Ophthalmol. 110:173, 1992. 8. Misiek, D. J., Kent, J. N., and Carr, R. F.: Soft tissue responses to hydroxylapatite particles of dif ferent shapes. J. Oral Maxillofac. Surg. 42:150, 1984. 9. Zide, M. F.: Late posttraumatic enophthalmos corrected by dense hydroxylapatite blocks. J. Oral Maxillofac. Surg. 44:804, 1986. 10. Reznick, J. B., and Gilmore, W. C : Host re sponse to infection of a subperiosteal hydroxylapa tite implant. Oral Surg. Oral Med. Oral Pathol. 67:665, 1989. 11. Kent, J. N., Quinn, J. H., Zide, M. F., Guerra, L. R., and Boyne, P. J.: Alveolar ridge augmentation using nonresorbable hydroxylapatite with or without autogenous cancellous bone. J. Oral Maxillofac. Surg. 41:629, 1983.
