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Descemet's membrane perforation during deep anterior lamellar keratoplasty: Prognosis
ARTICLE
Descemet’s membrane perforation during deep anterior lamellar keratoplasty: Prognosis Antonio Leccisotti, MD, PhD
PURPOSE: To evaluate the functional and endothelial prognosis after Descemet’s membrane perforation during deep anterior lamellar keratoplasty (DALK). SETTING: Private practice, Siena, Italy. METHODS: A retrospective study evaluated a series of 35 eyes that had DALK using the big-bubble technique. RESULTS: Intraoperative perforation occurred in 8 eyes (23%), in 5 eyes during manual deep dissection and in 1 eye each during trephination, as the air needle was introduced in the stroma, and as the big bubble was punctured. In all 8 eyes, DALK could be completed. In 1 case, pupillary block was caused by air left in the anterior chamber, resulting in permanent mydriasis and anterior subcapsular opacity. In another case, a double anterior chamber persisted and penetrating keratoplasty was later required. In the other 6 cases, the postoperative course was uneventful. The mean postoperative best spectacle-corrected visual acuity was 0.8 G 0.13 (SD) and the mean postoperative refractive astigmatism, 2.09 G 0.98 diopters. The mean endothelial cell loss, evaluated in 7 eyes, was 12% G 11% at 1 month (P<.05) and 14% G 12% at 12 months. The mean cell loss was 25% G 2.7% in eyes in which intraoperative reformation of the anterior chamber with air was required and 6% G 7.5% in eyes in which it was not (P< .05). CONCLUSIONS: Despite 2 complicated cases, intraoperative perforation during DALK had a good final functional prognosis. However, eyes in which the perforation required reformation of the anterior chamber had a mean endothelial cell loss greater than 20%. When air is left in the anterior chamber, close monitoring is required to avoid pupillary block. J Cataract Refract Surg 2007; 33:825–829 Q 2007 ASCRS and ESCRS
Deep anterior lamellar keratoplasty (DALK) is increasingly performed for the surgical correction of keratoconus and stromal corneal opacities.1–5 This technique spares the recipient corneal endothelium, with only the affected stroma replaced by the donor stroma. Fast visual rehabilitation after DALK is determined by the depth of the stromal dissection, with the best
Accepted for publication February 6, 2007. From the Ophthalmic Surgery Unit, Casa di Cura Rugani, Siena, Italy. The author has no financial or proprietary interest in any material or method mentioned. Corresponding author: Antonio Leccisotti, MD, PhD, Piazza V Bersaglieri 2, 53100 Siena, Italy. E-mail: [email protected]. Q 2007 ASCRS and ESCRS Published by Elsevier Inc.
results occurring with baring of the recipient Descemet’s membrane.5 The attempt to bare Descemet’s membrane can be complicated by its perforation, which can cause conversion to penetrating keratoplasty (PKP) or the collection of aqueous in the recipient–donor interface (ie, double anterior chamber), leading to stromal opacity.6 In addition, perforation at an earlier surgical stage leads to a shallower dissection and slower visual recovery because of stromal haze at the interface. Few studies2,7 have evaluated the prognosis of Descemet’s membrane perforation during DALK. In addition, some surgeons abandon DALK and convert to PKP whenever a perforation occurs,8,9 a strategy that is not justified as studies show it leads to poorer visual results. The present study was performed to determine the incidence, the moment, and the anatomic and 0886-3350/07/$dsee front matter doi:10.1016/j.jcrs.2007.02.016
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functional prognosis of Descemet’s membrane perforation during DALK. PATIENTS AND METHODS The charts of all patients who had DALK by the same surgeon (A.L.) between January and October 2005 were evaluated. All patients provided informed consent. Preoperative inclusion criteria for DALK were keratoconus or corneal stromal opacity, endothelial cell density greater than 1900 cells/mm2, minimum corneal thickness greater than 300 mm, and postoperative follow-up of at least 12 months. Patients were evaluated if they had perforation of Descemet’s membrane at any surgical stage as determined by external aqueous leakage. All patients had slitlamp microscopy, applanation tonometry, and dilated fundoscopy. The big-bubble surgical technique4,5 was used. Briefly, the recipient cornea was trephined with a disposable suction Hessburg-Barron 8.0 mm trephine (Altomed) to an approximate depth of 300 to 350 mm. A bent 30-gauge needle was inserted into the corneal stroma from the edge of trephination 12 o’clock to the paracentral area. Air was injected with force until the stroma was whitened by small intrastromal bubbles. A major bubble should be obtained in most cases, detaching Descemet’s membrane from the stroma. An anterior keratectomy was then performed with a sharp crescent blade, and a paracentesis was created. The air bubble was then punctured, and a common Barraquer spatula was inserted through the cut. The stromal tissue over the spatula was cut into flaps with a sharp blade, and Descemet’s membrane was thus bared. The stromal flaps were then removed with scissors. When the big bubble does not form, stromal dissection is performed manually by inserting the spatula horizontally into the stromal layers and cutting the stromal tissue over the spatula, layer by layer, reaching a pre-Descemetic plane. In cases of perforation with anterior chamber collapse, sterile air was injected into the anterior chamber through a paracentesis to reform it and allow further dissection. Air is preferred over an ophthalmic viscosurgical device because it need not be removed at the end and small bubbles indicate the perforation site during dissection. Multiple air injections may be required. If the anterior chamber cannot be reformed by air, the procedure is converted to PKP. The donor button was cut using an 8.25 mm Barron punch (Altomed), and the endothelium and Descemet’s membrane were peeled off with a forceps. The donor button was secured with a continuous curvilinear suture in the first 3 cases in the series and by 16 interrupted 10-0 nylon sutures in subsequent cases. Postoperative treatment consisted of levofloxacin 0.3% eyedrops 4 times daily, unpreserved dexamethasone 0.1% eyedrops 4 times daily, and unpreserved sodium hyaluronate 0.2% eyedrops every 2 hours while awake. When epithelialization was complete, only the topical dexamethasone was continued, tapered over 6 months. Interrupted sutures were removed gradually from the third to the sixth month, beginning with the tightest suture, revealed by tangential topography as a localized steepening. The continuous suture was generally removed after 5 to 6 months or when it loosened. Follow-up visits were at 1, 7, and 14 days and then monthly for 12 months. All examinations included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), slitlamp evaluation, tonometry, and
fundoscopy. At 1, 6, and 12 months, the central corneal endothelium was evaluated with a Robo-P specular microscope (Konan); cell density (cells/mm2) and the percentage of hexagonal cells (to evaluate polymorphism) were measured. The minimum number of cell entered in calculations was 40. Statistical analysis was performed using StatView (Abacus Concepts, Inc.). The 95% confidence intervals (CIs) were calculated using CIA software (BMJ).
RESULTS The series included 35 consecutive eyes of 35 patients who had DALK. Perforation occurred during DALK in 8 eyes (23%), which were all included in the study. No patient was excluded because of insufficient followup. Deep anterior lamellar keratoplasty was not converted into PKP in any case. Table 1 shows the characteristics of the 8 patients and the refractive results. The mean age of the patients (4 men, 4 women) was 37.3 years G 11.4 (SD) (range 23 to 55 years). Seven patients had keratoconus, and 1 had a deep stromal traumatic scar. All patients had surgery under general anesthesia except for patients 5 and 8, who received peribulbar anesthesia. The mean postoperative BSCVA was 0.8 G 0.13. The mean postoperative refractive astigmatism was 2.09 G 0.98 diopters. The mean endothelial cell density was 2527 G 327 cells/mm2 preoperatively, 2237 G 443 cells/mm2 1 month postoperatively, and 2179 G 471 cells/mm2 at 12 months (Table 2). The mean of differences between the preoperative and 1-month postoperative cell densities was 290 G 306 cells/mm2, with a 95% CI for the mean difference of paired samples of 8 to 573 (P!.05). The mean of differences between 1-month and 12-month cell densities was 58 G 114 cells/mm2, with a 95% CI for the mean difference of 48 to 163 (not statistically significant). The mean change from preoperatively to 1 month postoperatively was 12% G 11% and from preoperatively to 12 months postoperatively, 14% G 12%. The mean endothelial cell loss 12 months postoperatively was 25% G 2.7% in eyes in which intraoperative reformation of the anterior chamber with air was required (patients 1, 4, 5) and 6% G 7.5% in eyes in which it was not (patients 2, 6, 7, 8). The 95% CI for the difference between means was 7% to 31% (P! .05). Case Reports Patient 1 A perforation occurred during trephination, laterally from 2 to 4 o’clock. The cut was closed by 5 interrupted 10-0 nylon sutures, the anterior chamber was reformed with air, and air was gently injected into the stroma, avoiding big-bubble formation. Layer-by-layer manual dissection was performed until a pre-descemetic plane was reached. The sutures were
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Table 1. Characteristics of patients who had perforation during DALK and visual results at 1 year. Pt Age (Y) Sex Eye
Disease
Moment of Perforation Additional Complications
1 2 3
23 24 32
M F M
L L R
Keratoconus Keratoconus Keratoconus
Trephination Air needle insertion Manual dissection
4 5 6 7 8
37 55 31 52 45
M M F F F
R R L L L
Keratoconus Stromal scar Keratoconus Keratoconus Keratoconus
Manual dissection Big-bubble puncture Manual dissection Manual dissection Manual dissection
None None Double AC, stromal opacity, PKP None Pupillary block, mydriasis None None None
Refraction
Keratogr Cyl BSCVA
3.00
0.75 175 2.00 85 1.00 25
0.30 170 1.60 93 1.20 18
0.9 0.8 1.0
4.00 3.00 1.50 2.50
2.25 160 1.75 40 4.00 155 3.00 25 2.00 105
3.80 170 2.30 42 5.60 169 4.20 31 1.40 92
0.6 0.6 0.8 0.9 0.8
AC Z anterior chamber; BSCVA Z best spectacle-corrected visual acuity; Keratogr Cyl Z astigmatism on tangential videokeratography; PKP Z penetrating keratoplasty; Pt Z patient
then removed, and the donor button was sutured on the bed. The sutures were tightened enough to prevent formation of a double anterior chamber. The postoperative course was uneventful. The sutures were removed after 8 months.
excised opaque stroma and underlying recipient Descemet’s and endothelium revealed diffuse intrastromal edema and moderate chronic inflammation and fibrosis in the posterior aspect of the stroma and of the thickened Descemet’s membrane.
Patient 2 A microperforation in the bottom of the trephination groove at 12 o’clock was caused by the forced introduction of the air needle. The anterior chamber remained deep, so the needle was removed and inserted at 9 o’clock. A big bubble was not achieved, and layer-by-layer manual dissection was performed until a pre-descemetic plane was reached. The donor button was sutured. The postoperative course was uneventful.
Patient 4 A big bubble was not achieved. Descemet’s membrane was punctured during the last phases of stromal dissection. Air was injected into the anterior chamber, and the stromal dissection could be continued to a pre-descemetic plane. The donor button was sutured, and an uneventful postoperative course followed. Patient 5 A big bubble was achieved, but Descemet’s membrane was perforated as the air bubble was being punctured. This early perforation led to a residual stromal layer. The button was sutured and the anterior chamber filled with air. The eye was dilated and the patient kept supine. There was no evidence of pupillary block until late evening. However, the next morning the pupil was permanently dilated, the iris atrophied, and anterior ‘‘spilled milk’’ subcapsular opacities (glaukomflecken) were present. The lasting
Patient 3 A big bubble was not achieved. Two microperforations occurred, and air had to be repeatedly injected into the collapsing anterior chamber. The following day, a double anterior chamber was present and 2 attempts to resolve it by air injection were unsuccessful. The donor button became opaque; PKP was performed 2 months later. The course after PKP was uneventful. Histological examination of the
Table 2. Corneal endothelial changes after perforation during DALK. Preop
1 Month Postop
1 Year Postop
Pt
ECD (Cells/mm2)
HC
ECD (Cells/mm2)
HC
ECD Change from Preop (%)
ECD (Cells/mm2)
HC
ECD Change from Preop (%)
1 2 4 5 6 7 8
2675 2945 2664 2006 2591 2649 2161
58 62 41 56 55 61 45
2011 2898 1987 1632 2274 2733 2124
61 63 37 57 52 54 47
25 2 25 19 12 C3 2
1927 3010 2045 1516 2153 2511 2093
60 60 35 49 45 59 44
28 C2 23 24 17 5 3
ECD Z endothelial cell density; HC Z percentage of hexagonal cells; Pt Z patient
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effects of the peribulbar anesthesia might explain the absence of severe symptoms. Visual recovery was slow because of the hazy interface. After 6 months, the haze resolved and visual acuity improved. Patients 6, 7, and 8 A big bubble was achieved in patient 8, but not in patients 6 and 7. In all 3 cases, minor perforations occurred during the final stages of manual stromal dissection. Injecting air into the anterior chamber was not deemed necessary. The button was sutured, and the postoperative course was uneventful in all 3 cases (Figure 1). DISCUSSION The functional prognosis after perforation of Descemet’s membrane during DALK was good in 7 of 8 eyes in our series. One eye required a subsequent PKP. However, larger perforations caused greater endothelial cell loss and a case of pupillary block, the latter resulting from air left in the anterior chamber. Endothelial loss was worse (23% to 28%) when the collapsing anterior chamber was reformed intraoperatively with air, whereas a 0% to 17% reduction occurred in the other cases. The incidence of Descemet’s membrane perforation during DALK depends on the technique and the programmed depth. Reported incidences vary from 4.4% to 39%,2,7–13 with surgeon learning curve playing an important role.2 A risk factor is a preoperatively thin cornea.13 After perforation, the rate of immediate conversion to PKP in the most recent reports ranges from 0% to 100%7–13; including the present series, conversion has been reported in 8 of 53 eyes (15%).7–13 The moment of perforation is crucial for the completion and the success of DALK. Early perforations lead to a greater residual stroma and hence slower visual rehabilitation because of a hazy stromal interface. Perforations during trephination can be prevented by reducing trephination depth (eg, 300 to 350 mm), especially in cases of keratoconus. Their management requires suturing and moderate air injection in the stroma for subsequent manual dissection.5 In our series, patient 1 had a 400 mm trephination in a keratoconic cornea with a central 510 mm thickness, leading to perforation, possibly as a result of an oblique cut or inaccurate calculation of the depth of the cut. The most common postoperative complication of perforation is collection of fluid between the donor stroma and the recipient Descemet’s membrane (double anterior chamber).2 Air or gas injection into the anterior chamber is usually used to drain the collected aqueous humor; spontaneous resolution occurs in some cases.10 However, the air or gas bubble can cause pupillary block with a fixed dilated pupil and anterior subcapsular opacities.14 Hourly monitoring,
Figure 1. Transparent cornea with no haze at interface 1 week after DALK at pre-descemetic depth with minor intraoperative perforation (patient 7).
pharmacological mydriasis, and avoiding overinflation are necessary to prevent this complication.2 Few DALK series compare preoperative and postoperative endothelial status. A study in which air was systematically injected in the anterior chamber to visualize the posterior corneal surface11 induced a mean cell loss of 22.5% at 3 months, which is similar to the percentage loss to our subgroup in which air was used to reform the anterior chamber. In another DALK series in which air was not routinely introduced into the anterior chamber, an 11% mean cell loss was observed at 6 months.15 Multiple air injections might be associated with more severe endothelial damage because they indicate anterior chamber collapse. The weakness of the present study is that it was a small case series. However, this is the case with most DALK series reporting complications. In conclusion, the visual prognosis of Descemet’s membrane perforation during DALK is good as the procedure can be successfully completed in most cases. However, larger perforations causing intraoperative collapse of the anterior chamber (and requiring its reformation with air) can cause an immediate endothelial cell loss greater than 20%. Close monitoring to avoid pupillary block is required when air is left in the anterior chamber.
REFERENCES 1. Archila EA. Deep lamellar keratoplasty dissection of host tissue with intrastromal air injection. Cornea 1984/85; 3:217–218 2. Sugita J, Kondo J. Deep lamellar keratoplasty with complete removal of pathological stroma for vision improvement. Br J Ophthalmol 1997; 81:184–188 3. Melles GRJ, Lander F, Rietveld FJR, et al. A new surgical technique for deep stromal, anterior lamellar keratoplasty. Br J Ophthalmol 1999; 83:327–333
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4. Anwar M, Teichmann KD. Big-bubble technique to bare Descemet’s membrane in anterior lamellar keratoplasty. J Cataract Refract Surg 2002; 28:398–403 5. Anwar M, Teichmann KD. Deep lamellar keratoplasty; surgical techniques for anterior lamellar keratoplasty with and without baring of Descemet’s membrane. Cornea 2002; 21:374–383 6. Soong HK, Katz DG, Farjo AA, et al. Central lamellar keratoplasty for optical indications. Cornea 1999; 18:249–256 7. Al-Torbak AA, Al-Motowa S, Al-Assiri A, et al. Deep interior lamellar keratoplasty for keratoconus. Cornea 2006; 25:408–412 8. Senoo T, Chiba K, Terada O, et al. Deep lamellar keratoplasty by deep parenchyma detachment from the corneal limbs. Br J Ophthalmol 2005; 89:1597–1600 9. Fogla R, Padmanabhan P. Results of deep lamellar keratoplasty using the big-bubble technique in patients with keratoconus. Am J Ophthalmol 2006; 141:254–259 10. Pakrou N, Fung S, Selva D, et al. Deep lamellar keratoplasty in the treatment of keratoconus. Ophthalmologica 2006; 220: 164–169
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11. Fournie´ P, Coullet J, Moalic S, et al. Ke´ratoplastie lamellaire ante´rieure profonde dans le traitement chirurgical du ke´ratocoˆne. Recul de plus d’un an. [Deep anterior lamellar keratoplasty in the surgical treatment of keratoconus. A 1-year follow-up.]. J Fr Ophtalmol 2006; 29:602–613 12. Marchini G, Mastropasqua L, Pedrotti E, et al. Deep lamellar keratoplasty by intracorneal dissection; a prospective clinical and confocal microscopic study. Ophthalmology 2006; 113: 1289–1300 13. Michieletto P, Balestrazzi A, Balestrazzi A, et al. Factors predicting unsuccessful big bubble deep lamellar anterior keratoplasty. Ophthalmologica 2006; 220:379–382 14. Maurino V, Allan BDS, Stevens JD, Tuft SJ. Fixed dilated pupil (Urrets-Zavalia syndrome) after air/gas injection after deep lamellar keratoplasty for keratoconus. Am J Ophthalmol 2002; 133:266–268 15. van Dooren BTH, Mulder PGH, Nieuwendaal CP, et al. Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique). Am J Ophthalmol 2004; 137:397–400
J CATARACT REFRACT SURG - VOL 33, MAY 2007
Descemet’s membrane perforation during deep anterior lamellar keratoplasty: Prognosis Antonio Leccisotti, MD, PhD
PURPOSE: To evaluate the functional and endothelial prognosis after Descemet’s membrane perforation during deep anterior lamellar keratoplasty (DALK). SETTING: Private practice, Siena, Italy. METHODS: A retrospective study evaluated a series of 35 eyes that had DALK using the big-bubble technique. RESULTS: Intraoperative perforation occurred in 8 eyes (23%), in 5 eyes during manual deep dissection and in 1 eye each during trephination, as the air needle was introduced in the stroma, and as the big bubble was punctured. In all 8 eyes, DALK could be completed. In 1 case, pupillary block was caused by air left in the anterior chamber, resulting in permanent mydriasis and anterior subcapsular opacity. In another case, a double anterior chamber persisted and penetrating keratoplasty was later required. In the other 6 cases, the postoperative course was uneventful. The mean postoperative best spectacle-corrected visual acuity was 0.8 G 0.13 (SD) and the mean postoperative refractive astigmatism, 2.09 G 0.98 diopters. The mean endothelial cell loss, evaluated in 7 eyes, was 12% G 11% at 1 month (P<.05) and 14% G 12% at 12 months. The mean cell loss was 25% G 2.7% in eyes in which intraoperative reformation of the anterior chamber with air was required and 6% G 7.5% in eyes in which it was not (P< .05). CONCLUSIONS: Despite 2 complicated cases, intraoperative perforation during DALK had a good final functional prognosis. However, eyes in which the perforation required reformation of the anterior chamber had a mean endothelial cell loss greater than 20%. When air is left in the anterior chamber, close monitoring is required to avoid pupillary block. J Cataract Refract Surg 2007; 33:825–829 Q 2007 ASCRS and ESCRS
Deep anterior lamellar keratoplasty (DALK) is increasingly performed for the surgical correction of keratoconus and stromal corneal opacities.1–5 This technique spares the recipient corneal endothelium, with only the affected stroma replaced by the donor stroma. Fast visual rehabilitation after DALK is determined by the depth of the stromal dissection, with the best
Accepted for publication February 6, 2007. From the Ophthalmic Surgery Unit, Casa di Cura Rugani, Siena, Italy. The author has no financial or proprietary interest in any material or method mentioned. Corresponding author: Antonio Leccisotti, MD, PhD, Piazza V Bersaglieri 2, 53100 Siena, Italy. E-mail: [email protected]. Q 2007 ASCRS and ESCRS Published by Elsevier Inc.
results occurring with baring of the recipient Descemet’s membrane.5 The attempt to bare Descemet’s membrane can be complicated by its perforation, which can cause conversion to penetrating keratoplasty (PKP) or the collection of aqueous in the recipient–donor interface (ie, double anterior chamber), leading to stromal opacity.6 In addition, perforation at an earlier surgical stage leads to a shallower dissection and slower visual recovery because of stromal haze at the interface. Few studies2,7 have evaluated the prognosis of Descemet’s membrane perforation during DALK. In addition, some surgeons abandon DALK and convert to PKP whenever a perforation occurs,8,9 a strategy that is not justified as studies show it leads to poorer visual results. The present study was performed to determine the incidence, the moment, and the anatomic and 0886-3350/07/$dsee front matter doi:10.1016/j.jcrs.2007.02.016
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functional prognosis of Descemet’s membrane perforation during DALK. PATIENTS AND METHODS The charts of all patients who had DALK by the same surgeon (A.L.) between January and October 2005 were evaluated. All patients provided informed consent. Preoperative inclusion criteria for DALK were keratoconus or corneal stromal opacity, endothelial cell density greater than 1900 cells/mm2, minimum corneal thickness greater than 300 mm, and postoperative follow-up of at least 12 months. Patients were evaluated if they had perforation of Descemet’s membrane at any surgical stage as determined by external aqueous leakage. All patients had slitlamp microscopy, applanation tonometry, and dilated fundoscopy. The big-bubble surgical technique4,5 was used. Briefly, the recipient cornea was trephined with a disposable suction Hessburg-Barron 8.0 mm trephine (Altomed) to an approximate depth of 300 to 350 mm. A bent 30-gauge needle was inserted into the corneal stroma from the edge of trephination 12 o’clock to the paracentral area. Air was injected with force until the stroma was whitened by small intrastromal bubbles. A major bubble should be obtained in most cases, detaching Descemet’s membrane from the stroma. An anterior keratectomy was then performed with a sharp crescent blade, and a paracentesis was created. The air bubble was then punctured, and a common Barraquer spatula was inserted through the cut. The stromal tissue over the spatula was cut into flaps with a sharp blade, and Descemet’s membrane was thus bared. The stromal flaps were then removed with scissors. When the big bubble does not form, stromal dissection is performed manually by inserting the spatula horizontally into the stromal layers and cutting the stromal tissue over the spatula, layer by layer, reaching a pre-Descemetic plane. In cases of perforation with anterior chamber collapse, sterile air was injected into the anterior chamber through a paracentesis to reform it and allow further dissection. Air is preferred over an ophthalmic viscosurgical device because it need not be removed at the end and small bubbles indicate the perforation site during dissection. Multiple air injections may be required. If the anterior chamber cannot be reformed by air, the procedure is converted to PKP. The donor button was cut using an 8.25 mm Barron punch (Altomed), and the endothelium and Descemet’s membrane were peeled off with a forceps. The donor button was secured with a continuous curvilinear suture in the first 3 cases in the series and by 16 interrupted 10-0 nylon sutures in subsequent cases. Postoperative treatment consisted of levofloxacin 0.3% eyedrops 4 times daily, unpreserved dexamethasone 0.1% eyedrops 4 times daily, and unpreserved sodium hyaluronate 0.2% eyedrops every 2 hours while awake. When epithelialization was complete, only the topical dexamethasone was continued, tapered over 6 months. Interrupted sutures were removed gradually from the third to the sixth month, beginning with the tightest suture, revealed by tangential topography as a localized steepening. The continuous suture was generally removed after 5 to 6 months or when it loosened. Follow-up visits were at 1, 7, and 14 days and then monthly for 12 months. All examinations included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), slitlamp evaluation, tonometry, and
fundoscopy. At 1, 6, and 12 months, the central corneal endothelium was evaluated with a Robo-P specular microscope (Konan); cell density (cells/mm2) and the percentage of hexagonal cells (to evaluate polymorphism) were measured. The minimum number of cell entered in calculations was 40. Statistical analysis was performed using StatView (Abacus Concepts, Inc.). The 95% confidence intervals (CIs) were calculated using CIA software (BMJ).
RESULTS The series included 35 consecutive eyes of 35 patients who had DALK. Perforation occurred during DALK in 8 eyes (23%), which were all included in the study. No patient was excluded because of insufficient followup. Deep anterior lamellar keratoplasty was not converted into PKP in any case. Table 1 shows the characteristics of the 8 patients and the refractive results. The mean age of the patients (4 men, 4 women) was 37.3 years G 11.4 (SD) (range 23 to 55 years). Seven patients had keratoconus, and 1 had a deep stromal traumatic scar. All patients had surgery under general anesthesia except for patients 5 and 8, who received peribulbar anesthesia. The mean postoperative BSCVA was 0.8 G 0.13. The mean postoperative refractive astigmatism was 2.09 G 0.98 diopters. The mean endothelial cell density was 2527 G 327 cells/mm2 preoperatively, 2237 G 443 cells/mm2 1 month postoperatively, and 2179 G 471 cells/mm2 at 12 months (Table 2). The mean of differences between the preoperative and 1-month postoperative cell densities was 290 G 306 cells/mm2, with a 95% CI for the mean difference of paired samples of 8 to 573 (P!.05). The mean of differences between 1-month and 12-month cell densities was 58 G 114 cells/mm2, with a 95% CI for the mean difference of 48 to 163 (not statistically significant). The mean change from preoperatively to 1 month postoperatively was 12% G 11% and from preoperatively to 12 months postoperatively, 14% G 12%. The mean endothelial cell loss 12 months postoperatively was 25% G 2.7% in eyes in which intraoperative reformation of the anterior chamber with air was required (patients 1, 4, 5) and 6% G 7.5% in eyes in which it was not (patients 2, 6, 7, 8). The 95% CI for the difference between means was 7% to 31% (P! .05). Case Reports Patient 1 A perforation occurred during trephination, laterally from 2 to 4 o’clock. The cut was closed by 5 interrupted 10-0 nylon sutures, the anterior chamber was reformed with air, and air was gently injected into the stroma, avoiding big-bubble formation. Layer-by-layer manual dissection was performed until a pre-descemetic plane was reached. The sutures were
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Table 1. Characteristics of patients who had perforation during DALK and visual results at 1 year. Pt Age (Y) Sex Eye
Disease
Moment of Perforation Additional Complications
1 2 3
23 24 32
M F M
L L R
Keratoconus Keratoconus Keratoconus
Trephination Air needle insertion Manual dissection
4 5 6 7 8
37 55 31 52 45
M M F F F
R R L L L
Keratoconus Stromal scar Keratoconus Keratoconus Keratoconus
Manual dissection Big-bubble puncture Manual dissection Manual dissection Manual dissection
None None Double AC, stromal opacity, PKP None Pupillary block, mydriasis None None None
Refraction
Keratogr Cyl BSCVA
3.00
0.75 175 2.00 85 1.00 25
0.30 170 1.60 93 1.20 18
0.9 0.8 1.0
4.00 3.00 1.50 2.50
2.25 160 1.75 40 4.00 155 3.00 25 2.00 105
3.80 170 2.30 42 5.60 169 4.20 31 1.40 92
0.6 0.6 0.8 0.9 0.8
AC Z anterior chamber; BSCVA Z best spectacle-corrected visual acuity; Keratogr Cyl Z astigmatism on tangential videokeratography; PKP Z penetrating keratoplasty; Pt Z patient
then removed, and the donor button was sutured on the bed. The sutures were tightened enough to prevent formation of a double anterior chamber. The postoperative course was uneventful. The sutures were removed after 8 months.
excised opaque stroma and underlying recipient Descemet’s and endothelium revealed diffuse intrastromal edema and moderate chronic inflammation and fibrosis in the posterior aspect of the stroma and of the thickened Descemet’s membrane.
Patient 2 A microperforation in the bottom of the trephination groove at 12 o’clock was caused by the forced introduction of the air needle. The anterior chamber remained deep, so the needle was removed and inserted at 9 o’clock. A big bubble was not achieved, and layer-by-layer manual dissection was performed until a pre-descemetic plane was reached. The donor button was sutured. The postoperative course was uneventful.
Patient 4 A big bubble was not achieved. Descemet’s membrane was punctured during the last phases of stromal dissection. Air was injected into the anterior chamber, and the stromal dissection could be continued to a pre-descemetic plane. The donor button was sutured, and an uneventful postoperative course followed. Patient 5 A big bubble was achieved, but Descemet’s membrane was perforated as the air bubble was being punctured. This early perforation led to a residual stromal layer. The button was sutured and the anterior chamber filled with air. The eye was dilated and the patient kept supine. There was no evidence of pupillary block until late evening. However, the next morning the pupil was permanently dilated, the iris atrophied, and anterior ‘‘spilled milk’’ subcapsular opacities (glaukomflecken) were present. The lasting
Patient 3 A big bubble was not achieved. Two microperforations occurred, and air had to be repeatedly injected into the collapsing anterior chamber. The following day, a double anterior chamber was present and 2 attempts to resolve it by air injection were unsuccessful. The donor button became opaque; PKP was performed 2 months later. The course after PKP was uneventful. Histological examination of the
Table 2. Corneal endothelial changes after perforation during DALK. Preop
1 Month Postop
1 Year Postop
Pt
ECD (Cells/mm2)
HC
ECD (Cells/mm2)
HC
ECD Change from Preop (%)
ECD (Cells/mm2)
HC
ECD Change from Preop (%)
1 2 4 5 6 7 8
2675 2945 2664 2006 2591 2649 2161
58 62 41 56 55 61 45
2011 2898 1987 1632 2274 2733 2124
61 63 37 57 52 54 47
25 2 25 19 12 C3 2
1927 3010 2045 1516 2153 2511 2093
60 60 35 49 45 59 44
28 C2 23 24 17 5 3
ECD Z endothelial cell density; HC Z percentage of hexagonal cells; Pt Z patient
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DESCEMET’S MEMBRANE PERFORATION DURING DALK: PROGNOSIS
effects of the peribulbar anesthesia might explain the absence of severe symptoms. Visual recovery was slow because of the hazy interface. After 6 months, the haze resolved and visual acuity improved. Patients 6, 7, and 8 A big bubble was achieved in patient 8, but not in patients 6 and 7. In all 3 cases, minor perforations occurred during the final stages of manual stromal dissection. Injecting air into the anterior chamber was not deemed necessary. The button was sutured, and the postoperative course was uneventful in all 3 cases (Figure 1). DISCUSSION The functional prognosis after perforation of Descemet’s membrane during DALK was good in 7 of 8 eyes in our series. One eye required a subsequent PKP. However, larger perforations caused greater endothelial cell loss and a case of pupillary block, the latter resulting from air left in the anterior chamber. Endothelial loss was worse (23% to 28%) when the collapsing anterior chamber was reformed intraoperatively with air, whereas a 0% to 17% reduction occurred in the other cases. The incidence of Descemet’s membrane perforation during DALK depends on the technique and the programmed depth. Reported incidences vary from 4.4% to 39%,2,7–13 with surgeon learning curve playing an important role.2 A risk factor is a preoperatively thin cornea.13 After perforation, the rate of immediate conversion to PKP in the most recent reports ranges from 0% to 100%7–13; including the present series, conversion has been reported in 8 of 53 eyes (15%).7–13 The moment of perforation is crucial for the completion and the success of DALK. Early perforations lead to a greater residual stroma and hence slower visual rehabilitation because of a hazy stromal interface. Perforations during trephination can be prevented by reducing trephination depth (eg, 300 to 350 mm), especially in cases of keratoconus. Their management requires suturing and moderate air injection in the stroma for subsequent manual dissection.5 In our series, patient 1 had a 400 mm trephination in a keratoconic cornea with a central 510 mm thickness, leading to perforation, possibly as a result of an oblique cut or inaccurate calculation of the depth of the cut. The most common postoperative complication of perforation is collection of fluid between the donor stroma and the recipient Descemet’s membrane (double anterior chamber).2 Air or gas injection into the anterior chamber is usually used to drain the collected aqueous humor; spontaneous resolution occurs in some cases.10 However, the air or gas bubble can cause pupillary block with a fixed dilated pupil and anterior subcapsular opacities.14 Hourly monitoring,
Figure 1. Transparent cornea with no haze at interface 1 week after DALK at pre-descemetic depth with minor intraoperative perforation (patient 7).
pharmacological mydriasis, and avoiding overinflation are necessary to prevent this complication.2 Few DALK series compare preoperative and postoperative endothelial status. A study in which air was systematically injected in the anterior chamber to visualize the posterior corneal surface11 induced a mean cell loss of 22.5% at 3 months, which is similar to the percentage loss to our subgroup in which air was used to reform the anterior chamber. In another DALK series in which air was not routinely introduced into the anterior chamber, an 11% mean cell loss was observed at 6 months.15 Multiple air injections might be associated with more severe endothelial damage because they indicate anterior chamber collapse. The weakness of the present study is that it was a small case series. However, this is the case with most DALK series reporting complications. In conclusion, the visual prognosis of Descemet’s membrane perforation during DALK is good as the procedure can be successfully completed in most cases. However, larger perforations causing intraoperative collapse of the anterior chamber (and requiring its reformation with air) can cause an immediate endothelial cell loss greater than 20%. Close monitoring to avoid pupillary block is required when air is left in the anterior chamber.
REFERENCES 1. Archila EA. Deep lamellar keratoplasty dissection of host tissue with intrastromal air injection. Cornea 1984/85; 3:217–218 2. Sugita J, Kondo J. Deep lamellar keratoplasty with complete removal of pathological stroma for vision improvement. Br J Ophthalmol 1997; 81:184–188 3. Melles GRJ, Lander F, Rietveld FJR, et al. A new surgical technique for deep stromal, anterior lamellar keratoplasty. Br J Ophthalmol 1999; 83:327–333
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4. Anwar M, Teichmann KD. Big-bubble technique to bare Descemet’s membrane in anterior lamellar keratoplasty. J Cataract Refract Surg 2002; 28:398–403 5. Anwar M, Teichmann KD. Deep lamellar keratoplasty; surgical techniques for anterior lamellar keratoplasty with and without baring of Descemet’s membrane. Cornea 2002; 21:374–383 6. Soong HK, Katz DG, Farjo AA, et al. Central lamellar keratoplasty for optical indications. Cornea 1999; 18:249–256 7. Al-Torbak AA, Al-Motowa S, Al-Assiri A, et al. Deep interior lamellar keratoplasty for keratoconus. Cornea 2006; 25:408–412 8. Senoo T, Chiba K, Terada O, et al. Deep lamellar keratoplasty by deep parenchyma detachment from the corneal limbs. Br J Ophthalmol 2005; 89:1597–1600 9. Fogla R, Padmanabhan P. Results of deep lamellar keratoplasty using the big-bubble technique in patients with keratoconus. Am J Ophthalmol 2006; 141:254–259 10. Pakrou N, Fung S, Selva D, et al. Deep lamellar keratoplasty in the treatment of keratoconus. Ophthalmologica 2006; 220: 164–169
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11. Fournie´ P, Coullet J, Moalic S, et al. Ke´ratoplastie lamellaire ante´rieure profonde dans le traitement chirurgical du ke´ratocoˆne. Recul de plus d’un an. [Deep anterior lamellar keratoplasty in the surgical treatment of keratoconus. A 1-year follow-up.]. J Fr Ophtalmol 2006; 29:602–613 12. Marchini G, Mastropasqua L, Pedrotti E, et al. Deep lamellar keratoplasty by intracorneal dissection; a prospective clinical and confocal microscopic study. Ophthalmology 2006; 113: 1289–1300 13. Michieletto P, Balestrazzi A, Balestrazzi A, et al. Factors predicting unsuccessful big bubble deep lamellar anterior keratoplasty. Ophthalmologica 2006; 220:379–382 14. Maurino V, Allan BDS, Stevens JD, Tuft SJ. Fixed dilated pupil (Urrets-Zavalia syndrome) after air/gas injection after deep lamellar keratoplasty for keratoconus. Am J Ophthalmol 2002; 133:266–268 15. van Dooren BTH, Mulder PGH, Nieuwendaal CP, et al. Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique). Am J Ophthalmol 2004; 137:397–400
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