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A New Lamellar Wound Configurationfor Penetrating Keratoplasty Surgery

Massimo Busin, MD

Amodified penetrating keratoplasty procedure with a new lamellar configuration of the

surgical wound was performed on 8 eyes with endothelial decompensation. This tech-

nique allows complete suture removal by 3 months postoperatively, substantially short-

ening the time necessary for visual rehabilitation. Refractive astigmatism before and

after suture removal was minimized to 4 diopters or less in all of the eyes in our preliminary series.

Because the anterior surface of the donor button is smaller than the posterior one (diameter, 7.0mm and 9.0 mm, respectively), more endothelial cells can be transplanted while maintaining

the anterior graft surface at a safe distance from the corneoscleral limbus. Finally, no expensive

instrumentation is required for this procedure except for an artificial anterior chamber if whole

globes are not available. The surgical technique and clinical results are presented in this article.

Arch Ophthalmol. 2003;121:260-265

During the past decades, penetrating kera-toplasty (PK) surgery has undergone con-tinuous refinement. Various instrumentshave been developed to improve the qual-ity of trephination in both donor and re-

cipient corneas, and countless suturingtechniques have been used to reduce tis-sue distortion and minimize postopera-tive refractive errors.1-9 Nevertheless, todate, the basic concept of cutting a donordisc with a “perfect” margin to fit into a“perfect”hole hasremained thesame. Thismethod produces a vertical, edge-to-edge PK wound. Regardless of how per-fectly the donor and recipient cornea fit,this type of wound requires relatively tightsutures to hold the edges together until thehealing is sufficient to withstand the effectof the intraocular pressure; this usually

takes at least 1 year.Because of this approach, refraction

is not stable, and astigmatism (often of theirregular type) cannot be adequately cor-rected in many patients as long as the su-tures are present.1-9 In addition, when thesutures are removed, substantial changesin refraction are frequently seen, possi-

bly resulting in anisometropia and/or high-degree astigmatism.10-14 Finally,wound de-hiscence occurs after suture removal in upto 4% of cases, even if this is done morethan 1 year after surgery.15-18

Inrecentyears,differenttypesoflamel-larkeratoplasty(LK)procedureshavegainedpopularityamongcornealsurgeonsinanat-tempttotransplantselectedlayersofthecor-nea,speedingwoundhealingwhileoptimiz-ing postoperative refraction.19,20 Withthesemethodsahorizontal,surface-to-surfacesur-gicalwoundresults,andtheintraocularpres-suretendstomakethelayersadheretoeachotherratherthangape.Tightsuturingisnotnecessary, and removal can safely be per-formedmuchearlierthanafterconventionalPK surgery. However, the presence of a la-mellartissue interface mayreducethequal-

ityofvisionafterLKcomparedwiththatob-tained following PK surgery.

To combine the optical superiority of PK with the wound-healing advantages of LK, the standard PK technique was modi-fied by using a full-thickness donor graft inconjunction with a peripheral lamellarwound configuration (Figure 1). The sur-gical technique and the results obtained in8 eyes of 8 patients with endothelial de-compensation are presented in this article.

From the Departments of Ophthalmology, Casa di Cura Villa Serena Hospital, Forli,Italy, and Ospedale S Carlo di Nancy, Rome, Italy.

SURGICAL TECHNIQUE

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METHODS

The use of a modified PK procedure in8 consecutive patients with endothelialdecompensation (aphakic bullouskera-topathy, n=1; pseudophakic bullouskeratopathy, n=6; and Fuchs endothe-lial corneal dystrophy, n=1) is re-ported. All procedures were performedby thesame surgeon(M.B.) between Sep-

tember and November 2001, and the re-sults were evaluated in a prospectivestudy, described as follows.

Preoperatively, the medical historyof each patient was recorded, anda com-plete eye examination was performed in-cluding visual acuity testing, slitlamp ex-amination, retinoscopy, and B-scanultrasonography when necessary (n= 2).Details regarding preoperative data aregiven in Table 1. Postoperatively, pa-tientswere seen twice a week until reepi-thelialization was completed, which oc-curred within 2 weeks of surgery in allcases. Uncorrected visualacuity was mea-

sured every week postoperatively. Onemonth after surgery, patients underwentrefraction, anduncorrected andbestspec-tacle-corrected visual acuity were deter-mined. In addition, keratometry andcorneal topography analysis were ob-tained. Monthly examinations were per-formed thereafter. Sutures were re-moved 3 monthsafter surgery in allcases.Each patient underwent a repeated com-plete eye examination 1 month after su-ture removal.

Surgical Technique

A detailed consent form was signed byall8 patients undergoing surgery. Allpa-tients were sedated with 3 mL of intra-venous droperidol immediately prior toanesthetic injection. Localanesthesia wasadministered with a peribulbar injec-tion of a mixture of 2% lidocaine and0.5% bupivacaine hydrochloride.

The donor button was mounted onanartificialanteriorchamber(Moria,Paris,France)after a viscoelasticsubstance wasplaced on the endothelium. Thegeomet-riccenterof the corneawas marked, anda7.0-mmBarronsuctiontrephinewasusedto makea circular, 0.3-mm-deepincision(Figure2A). A lamellar stromal dissec-tion wascarriedoutwitha bevel-upknifefrom the base of the incision all the wayto the limbus (Figure 2B). Then the cor-neawas removed from theartificialante-riorchamber and placedon theplateof aBarron suction punch with the endothe-lialsideup, taking careto align the mark

of the geometric center with the centralhole of thepunch. A 9.0-mmdonor but-tonwaspunchedout(Figure2C).Thepre-vious lamellardissectionallowed a super-ficialannular stromal lamella, 0.3mm inthickness, to be removed in the area be-tween 7.0 and 9.0 mm in diameter (Fig-ure2D). Thedonor buttonobtainedthisway consisted of a central, full-thicknesspart, 7.0mm in diameter,surrounded bya peripherallamellarwing ofdeepstromaandendotheliumthatwas1.0mminwidth

(Figure 2E). A McNeill-Goldman ring21

was used to fixate the globe. The recipi-ent bed wasprepared to closely conformto the shape of the donor button. A 7.0-mm Barronsuction trephine wasused tocut a circular incision 0.3 mm in depth(Figure3A). A lamellar stromal dissec-tion wascarriedoutwitha bevel-upknifefromthebaseof the incisionabout1 mmperipherally (Figure 3B). The anterior

chamber was then entered, and cornealscissors were used to complete the exci-sion of the corneal button at the periph-eral endof theposterior lamellarstromaldissection(Figure 3C). Thedonorbuttonwas positioned by sliding the peripheralwing underthe 1.0-mm-widesuperficialstromallipoftherecipientbed.Four10-0nylon cardinal sutures were putin place.Eachsutureexitedthedonorbuttonatthebase of the wing and was then passedthroughthe superficial recipientlamellaeattheendofthedissection.Thisway,thewing was left free to adhere to the poste-riorsurfaceof thedissected recipient cor-

nea, an effectof theintraocular pressure.ContrarytowhatistypicallyobservedwithconventionalPK surgery, theinjectionof balanced salt solution into the anteriorchambershowedthat thesurgical woundwas already completely watertight (Fig-ure 3D). The procedure was completedwith a single10-0 nylon running suture,each bite of which was passed in a fash-ionsimilartothatpreviouslydescribedforthe cardinalsutures.Finally,the cardinalsutures wereremoved (Figure3E). Addi-

Table 1. Preoperative Data Collected From Patients Undergoing Modified Penetrating Keratoplasty Surgery

Patient No. 1 2 3 4 5 6 7 8

Age, y 68 81 94 63 77 78 72 84

Sex M M F F M F F F

Preoperative diagnosis PBK PBK PBK Fuchs dystrophy PBK PBK PBK ABK

Preoperative visual acuity* HM HM CF HM HM CF CF HM

Abbreviations: ABK, aphakic bullous keratopathy; CF, counting fingers; HM, hand motions; PBK, pseudophakic bullous keratopathy.*Not improvable because of corneal edema.

A B

Area of Lamellar Healing

Recipient Cornea

Recipient Cornea



Full-Thickness Graft

Figure 1. Schematic representation of the cornea after a nut-and-bolt keratoplasty procedure. Both in the cross section (A) and the frontal view (B), the annulararea of lamellar healing is outlined between the recipient corneal bed (outside) and the full-thickness part of the graft (inside).










tionalproceduresperformed in combina-tionwithPKsurgeryinthisseriesincludedanteriorvitrectomy(n=4),anteriorvitrec-tomy combinedwith theexchangeof theintraocular lens implant (n= 1), anteriorvitrectomycombinedwithintraocularlensimplantation (n=1), and pupilloplasty(n= 1). After surgery the patients under-

wentpressurepatchingovernight.Begin-ning the next morning, 0.1% dexameth-asone sodium phosphateand gentamicinsulfateantibiotic eyedropswere adminis-tered every 2 hours and tapered for 10weeks.

RESULTS

Surgery was uneventful in all pa-tients. All corneas gradually cleared

withtime, and reepithelializationwascompleted within 2 weeks of sur-gery. Data recorded preoperatively,1 month after surgery, and 1 monthafter suture removal are summa-rized in Tables 1 to 3. The 10-0 ny-lon running suture was removed 3

months after surgery in all patients(Figure 4). As early as 1 month af-ter surgery (Table 2), an uncor-rected visual acuity of at least 20/ 200 in the affected eye was recordedin all but 1 patient (patient 4 in thetables), who had high-degree myo-pia. Best spectacle-corrected visualacuity ranged between20/100and20/ 40. One month after suture removal(Table 3), both uncorrected and

spectacle best-corrected visual acu-ity further improved, and 6 of 8 pa-tients could see 20/60 or better withspectacle correction.Reasonsforbest-corrected vision worse than 20/60were macular myopic degeneration(patient 4) and cystoid macular

edema (patient 8). One month aftersurgery (Table 2), the refractivespherical equivalent ranged from+0.75 diopters (D) to −8.5 D. Meankeratometric readings ranged from40.5 D to 44.5 D. The refractiveastig-matic error was 4 D or less in allcases. Computerized analysis of cor-neal topography showed regularmorphologic characteristics of theastigmatism in all patients at all

A

C D E

B

Figure 2. Preparation of the donor button. A, Partial trephination of the donor cornea mounted on the artificial chamber. B, Lamellar dissection from the base ofthe incision all the way to the limbus. C, Donor button, 9.0 mm in diameter, with the endothelial side up. D, Superficial annular stromal lamella, 0.3 mm inthickness, removed from the donor button in the area between 7.0 and 9.0 mm of diameter. E, Donor button consisting of a central, full-thickness part, 7.0 mm indiameter, surrounded by a peripheral lamellar wing of deep stroma and endothelium, 1.0 mm in width.










examination times (Figure 5). Sur-prisingly, sutureremoval did notsub-stantially affect refraction in any pa-tient (Table 3). Again, refractiveastigmatism was 4 D or less in allcases. Notably, the preoperative spec-tacle cylinder in patient 4 was 4 D.

COMMENT

Despite the excellent prognosis of PK, visual rehabilitation of patientsundergoing this procedure is slowand frequently hampered by high-degree astigmatism, often of theirregular type.1-9 Factors includinghost-graft disparity,trephinationtech-nique,andsuturing techniquearebe-lieved to affect the regularity of graft

curvature. In addition, even ifallothervariables could theoretically be opti-mized, recovery of vision can be de-layed by corneal distortion second-ary to the presence of sutures; somedegreeof tension-induced tissueroll-ing is necessary to obtain a water-tight wound. Healing of these verti-

cal, edge-to-edge corneal woundsrequiresa minimum of 6 months andtypically 1 year in adults. In a rela-tively high number of patients, stablevision is not achieved until manymonths after PK surgery, often fol-lowing suture removal.1-14

Lamellar keratoplasty has beenproposed in different forms as an al-ternative surgical treatment for vari-ouscornealdiseases. Comparedwith

PK, LK offers the substantial advan-tageof creating a horizontal, surface-to-surfacetypeof surgical wound.In-traocular pressure helps thesurfacesadhereto oneanother,so thesuturesrequireminimal tension and may beremoved 2 to 4 monthsaftersurgery.Todate,however,mostofthesemeth-

odshavenotgainedpopularity,mainlybecauseofthelowerpostoperativeop-ticalquality ofthe cornea. The use of themicrokeratometo performlamel-lar dissectionsin laser-assistedin situkeratomileusishas shown thatLKcanresult in postoperative visual acuityof 20/20. We recently published theinitial results of endokeratoplasty, aposteriorLKprocedureaimedattrans-plantingthe posterior stromaanden-

A

C D E

B

Figure 3. Main surgical steps of the nut-and-bolt keratoplasty procedure. A, Partial trephination of the recipient bed, 7.0 mm in diameter (same as for the donorcornea) and 0.3 mm in depth. B, Lamellar stromal dissection carried out from the base of the incision about 1 mm peripherally. C, Excision of the cornealbutton using corneal scissors at the peripheral end of the posterior lamellar stromal dissection. D, Injection of balanced salt solution into the anterior chambershows that the surgical wound is perfectly watertight with just 4 cardinal sutures in place. E, A single running 10-0 nylon suture is used to completethe procedure.










dothelium in decompensated cor-neas.20 Although these results arepromising,someconcern remainsforthe sudden considerable decrease inintraocular pressure(frommorethan60mmHgwhenusingthemicrokera-tome to 0 mm Hg after the anteriorchamber is entered) during the pro-cedure, as well as the relatively lim-

ited amount of transplanted endo-thelium (the donor button does notexceed7.0mmindiameter).Inaddi-tion, the need for special instrumen-tationnoticeably increases thecostof surgery,and notallsurgeons have ac-cess to a microkeratome.

The surgical technique de-scribed in this article is designed tocombine the advantages of PK andLK techniques. For this reason, 2 dis-tinct components are assembled inthe donor button, which is shapedlike a “reversed mushroom.” Thecentral, full-thickness part, 7.0 mmin diameter, maintains theoptical ad-

vantages of grafts used for conven-tional PK surgery while remainingconfined within a safe distance fromthe corneoscleral limbus. The pe-ripheral wing of deep stroma anden-dothelium, 1 mm in width, createsan annular area of lamellar healing

around the full-thickness compo-nent. Because both thedonor andre-cipient corneas undergo dissectionby hand, thehealing process is simi-lar to that in clear-cornea cataractsurgery except that thewound is ex-tended for 360° instead of being lim-ited to the area of the tunnel. In thisprocedure, sutures merely prevent

thedonor button from sliding out of position. They need not be as tightas when they seal thesurgicalwoundbecause the intraocular pressuretends to push the healing surfacestogether. Our series demonstratedthat with this method, it is possibleto have a full-thickness graft com-pletely free of sutures as early as 3months after surgery, thus signifi-cantly shortening the time neces-sary for visual rehabilitation.

The degree of astigmatism re-corded both before and after suture

removal was low in almost all pa-tients; the only patient with a rela-tively high value (4 D) had a similarpreoperative spectacle correction.Corneal topography (Figure 5) con-firmed this data and further sup-ports the favorable comparison withconventional PK surgery.The nut-and-bolt type of fitting obtained be-tween the donor and recipient cor-neas with our PK modification, aswell as the consequent relative lax-ity of the suturing technique used,may bethe main reasons for thisfind-

ing. However, this wound construc-tion is only one of many possibletechniques based on the nut-and-

Figure 4. Clinical picture of patient 4 in this series, 1 day after suture removal. The graft is crystal clear inits full-thickness part, surrounded by the hazier annular area of lamellar healing.

Table 2. Data Collected 1 Month Postoperatively From Patients Undergoing Modified Penetrating Keratoplasty Surgery

Patient No. 1 2 3 4 5 6 7 8

UCVA 20/200 20/100 20/60 HM 20/100 20/60 20/50 20/200

BCVA 20/60 20/60 20/40 20/200 20/60 20/50 20/40 20/100

Spherical equivalent, D −1.75 −1.25 −0.5 −8.5 −1.5 +0.75 −0.5 −1.0

Refractive astigmatism, D 2.25 1.5 1.0 4.0 3.0 2.0 1.0 2.75

Mean keratometry reading, D 44.5 43.0 42.5 40.5 41.25 41.0 42.75 42.5

Abbreviations: BCVA, best-corrected visual acuity; D, diopters; HM, hand motions; UCVA, uncorrected visual acuity.

Table 3. Data Collected 1 Month After Suture Removal From Patients Undergoing Modified Penetrating Keratoplasty Surgery

Patient No. 1 2 3 4 5 6 7 8

UCVA 20/100 20/200 20/50 HM 20/100 20/60 20/50 20/100

BCVA 20/60 20/60 20/40 20/200 20/40 20/30 20/25 20/100

Spherical equivalent, D −2.25 −1.5 −0.5 −7.5 −1.75 +1.0 −1.0 −1.0

Refractive astigmatism, D 2.5 1.75 0.75 4.0 3.0 1.5 1.0 2.25

Mean keratometry reading, D 44.75 43.0 43.0 40.5 42.0 41.0 43.0 42.5

Abbreviations: BCVA, best-corrected visual acuity; D, diopters; HM, hand motions; UCVA, uncorrected visual acuity.










bolt principle. Thediametersof both

the full-thickness component andperipheral wing could be varied toachievedifferentpurposes.Theformercould be cut smaller to reduce thepossibility of immunologic rejectionthrough contact withperipheralcor-nealneovascularization, whereas thelattercouldbemadelargertoincreasetheamountofendothelialcellstrans-planted. Patientsundergoingthe pro-ceduredescribedinthisarticlereceivedmoreofthedonorendothelium(sur-face diameter,9.0 mm) than patientswhoreceivetheconventionalPKtech-

nique usually do (surface diameter,7.5-8.5mm).Incontrast,smallergraftsmay be used in patients with kerato-conus (as littleas 5.5 mmfor the an-teriorsurfaceand7.5mmforthepos-terior surface) to leave the reservoirofendothelialcellsintherecipientpe-ripheral cornea as large as possible.Also, the dimensional relationshipbetween the 2 components could bemodified: a smaller central part withalargerwingcouldbefittedwithevenlooser sutures or perhaps stabilizedwith the useof biologic glue, achiev-

ing a sutureless PK.Finally, discrep-ancies between trephination of thedonor button and recipient bed mayfurtherimprovetheresultscomparedwith those obtainedwith thepresenttechnique. The diameter of the full-thickness part of the donor button,forexample, couldbeslightlysmallerthanthetrephination oftherecipientbed;thesurgicalwoundwouldstillbewatertightowing to the internal tam-

ponade of the peripheral wing, and

scar tissue would fill up the smallspace between the donor and recipi-ent corneas, thus preventing graftdistortion.

In conclusion, our preliminarydata show thata lamellar woundcon-struction based on the nut-and-boltconcept may optimize postkerato-plasty refractiveerror while substan-tially speeding up visual recovery. Tofit specific indications, the amount of endothelium transplantedcan be var-ied by changing the diameter of theposterior surface of the donor but-

ton. No expensive or particular in-strumentation is needed if wholeglobes are available, and a relativelyinexpensive artificial anterior cham-ber may be used with excised cor-neas. Although postoperative fol-low-upof these patientswasrelativelyshort,thedatawere obtained1 monthafter suture removal; no substantialchanges in refractionareusually seenafter thispoint withconventionalPKsurgery. Despite the limited num-ber of patients, the preliminary datasuggest that this technique holds

great promise. However, the initialpositive results obtained in this se-ries require confirmation in a muchlarger population with a follow-upperiod of several years.

Submitted for publication May 2, 2002; final revision received July 11, 2002; accepted August 6, 2002.

I thankStefano Ferrari andMarioCarta from Emmeci Quattro SRL

(Parma, Italy) for providing equip-ment essential to carry out this study.

Corresponding author and re- prints: Massimo Busin, MD, Via Sisa33, 47100 Forlı̀, Italy (e-mail: [email protected]).

REFERENCES

1. McNeill JI, Kaufman HE. A double running su-ture technique for keratoplasty: earlier visual re-habilitation. Ophthalmic Surg. 1977;8:58-61.

2. Davison JA, Bourne WM. Results of penetratingkeratoplasty using a double running suture tech-nique. Arch Ophthalmol. 1981;99:1591-1595.

3. McNeill JI,WesselsIF. Adjustment ofsingle con-tinuous suture to control astigmatism after pen-etratingkeratoplasty.RefractCornealSurg. 1989;5:216-223.

4. Musch DC, Meyer RF, Sugar A, Soong HK. Cor-neal astigmatism after penetrating keratoplasty.Ophthalmology. 1989;96:698-703.

5. Van Meter WS, Gussler JR, Soloman KD, WoodTO. Postkeratoplasty astigmatism control. Oph- thalmology. 1991;98:177-183.

6. Assil KK, Zarnegar SR, Schanzlin DJ. Visual out-come after penetrating keratoplasty with doublecontinuous or combinedinterrupted andcontinu-

ous suture wound closure. Am J Ophthalmol.1992;114:63-71.

7. De Molfetta V, Brambilla M, De Casa N, et al. Re-sidual corneal astigmatism afterperforatingkera-toplasty. Ophthalmologica. 1980;179:316-321.

8. Perlman EM. An analysis andinterpretationof re-fractiveerrors after penetrating keratoplasty. Oph- thalmology. 1981;88:39-45.

9. Samples JR, Binder PS. Visual acuity, refractiveerror, and astigmatism following corneal trans-plantation for pseudophakic bullous keratopa-thy. Ophthalmology. 1985;92:1554-1560.

10. Musch DC, Meyer RF, Sugar A. The effect of re-movingrunning sutureson astigmatismafterpen-etratingkeratoplasty.Arch Ophthalmol. 1988;106:488-492.

11. Binder PS. The effect of suture removal on post-keratoplasty astigmatism. Am J Ophthalmol.1988;105:637-645.

12. Lin DTC, Wilson SE, Reidy JJ, et al. Topographicchanges that occur with 10-0 nylon suture re-moval followingkeratoplasty. Refract CornealSurg.1990;6:21-25.

13. MaderTH,YuanR, Lynn MJ,et al.Changesin kera-tometric astigmatism after suture removal morethanone yearafter penetrating keratoplasty.Oph- thalmology. 1993;100:119-127.

14. Davis EA,AzarDT, JakobsFM, Stark WJ.Refrac-tive and keratometric results after triple proce-dure: experience with early and late suture re-moval. Ophthalmology. 1998;105:624-630.

15. BinderPS,AbelR, PolackFM,KaufmanHE. Kera-toplasty wound separations. Am J Ophthalmol.1975;80:109-115.

16. Farley MK, Pettit TH. Traumatic wound dehis-cence after penetrating keratoplasty. Am J Oph- thalmol. 1987;104:44-49.

17. RehanyU, RumeltS. Oculartraumafollowingpen-

etratingkeratoplasty.Arch Ophthalmol. 1998;116:1282-1286.18. TsengSH, LinSC,ChenFK.Traumatic woundde-

hiscence after penetrating keratoplasty. Cornea.1999;18:553-558.

19. MellesGR,LanderF, VanDoorenBT,PelsE,BeekhuisWH. Preliminaryclinical resultsof posterior lamel-larkeratoplastythrough a sclerocornealpocketin-cision. Ophthalmology. 2000;107:1850-1856.

20. Busin M, Arffa RC,Sebastiani A. Endokeratoplastyas analternative to penetrating keratoplasty forthesurgical treatment of diseased endothelium. Oph- thalmology. 2000;107:2077-2082.

21. Goldman KN, McNeill JI. The McNeill-Goldmanring. Ophthalmology. 1978;85:883-884.

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SIM Ks:42.24 D (7.99) @ 88°

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pwr: 42.24 Drad: 7.99 mmdis: 0.00 mmaxis: 8°

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Figure 5. Computerized analysis of the corneal topography of patient 6 in this series, performed 1 monthafter suture removal, shows the presence of a low-degree, regular astigmatism.








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