The authors have no one to acknowledge.

The study was approved by the Ethics Committee Review Board of Peking University Third Hospital and conformed to the Declaration of Helsinki. The new method of surgery named Pentagram Suturing Anterior Chamber Plasty (PSACP) was approved by the medical technology clinical application management Committee Review Board of Peking University Third Hospital. All the patients undergoing PSACP had provided written informed consent before the surgery.
1. Preparations before PSACP
<ol>
	<li>Perform ophthalmic examinations for all the patients, including a visual acuity assessment, rebound tonometer, color slit lamp photography (Figure 1A,B), and ophthalmic ultrasound.</li>
	<li>Display the range of anterior synechia by anterior segment optical coherence tomography (ASOCT) and ultrasound biomicroscopy (UBM) to design the position of incisions (Figure 1C,D and Figure 2).</li>
	<li>Ensure adequate availability of 10-0 polypropylene sutures on a STC-6 needle, 29 G syringe, cohesive viscoelastic, and balanced salt solution (BSS) (see Table of Materials).</li>
	<li>Provide general anesthesia with 2% lidocaine hydrochloride injection (2.5 mL) (see Table of Materials).</li>
	<li>Place the patient in a supine position with routine disinfection, towel laying, film sticking, and palpebral fissure opening by an eye speculum.</li>
</ol>
2. Surgical procedure
<ol>
	<li>Mark the five scleral puncture points 1.5 mm posterior to the limbus keeping away from the anti-glaucoma filtration bleb with 1% crystal violet solution. Ensure that the circular degree between the adjacent puncture points is 72&#176; (Figure 3).</li>
	<li>Remove the edematous epithelium of the cornea with a sclera tunnel knife. 
	&#8203;NOTE: Hypertonic glucose solution is recommended to reduce corneal stromal swelling.</li>
	<li>Make a limbus incision (1 mm), inject cohesive viscoelastic to separate the anterior synechia of the iris, and remove the fibrous membranes when necessary.</li>
	<li>Perform blunt separation for peripheral anterior synechia (PAS).</li>
	<li>Insert the 16 mm (STC-6) needle from the position 1 mm beside one of the puncture points (Figure 3) into the anterior chamber and retrieve across the surface of the iris within the bore of a 29 G syringe from another side puncture point with a circular distance of 144&#176; (Figure 3).</li>
	<li>When the 16 mm (STC-6) needle comes out from the anterior chamber, select the next inserting point 1 mm beside the retrieve point and 1.5 mm posterior to the limbus (Figure 3).</li>
	<li>Repeat steps 2.5-2.6 until the retention sutures in the anterior chamber form a pentagram-like barrier on the surface of the iris and pupil.</li>
	<li>Tie a surgical knot from the initial insert point and embed it into the superficial sclera under the bulbar conjunctiva.</li>
	<li>Perform the anterior chamber irrigation with BSS. Ensure removing all the viscoelastic, and then seal the incisions to watertight by a sterile irrigateor (see Table of Materials).</li>
</ol>

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The authors have nothing to disclose.

Bullous keratopathy with extensive anterior synechia has been considered one of the most challenging clinical problems. Although well-controlled IOP with successful lens extraction and anterior vitrectomy surgery was performed, the iris lens diaphragm was still flabby with the existence of an atrophied and tension-free iris. Case 1 showed that even when PKP was completed, conventional anterior chamber plasty with synechia separation would only partially and temporarily form in the anterior chamber. The main reasons are: (1) the aqueous humor circulation would continuously push and squeeze the atrophied and tension-free iris forward; (2) the effect of &#34;roller&#34; formed in the process of inflammation or restoration would make the iris from PAS to extensive anterior synechia again; (3) the fibration would result in synechia from iris to the cornea.
Keratoplasty with iris-diaphragm IOL implantation was a valuable method to cure the bullous keratopathy with aniridia10,11,12,13,14. To solve such extensive anterior synechia of the iris, iris-diaphragm IOL implantation after removing the iris might work15. However, total iridectomy was a surgery with significant iatrogenic injury, and iris-diaphragm IOL comes at an unaffordable price in China. A new method of forming a stable anterior chamber without recurrent extensive anterior synechia was needed to be explored.
Gentile et al.16 first reported the &#34;# pattern&#34; retention sutures across the anterior chamber to simulate an iris diaphragm. They made the sutures act as a barrier between the silicone oil and aqueous, preventing silicone oil-corneal contact, and this has been effective over 3-6 months. To deal with an atrophied and tension-free iris, there must be enough line segments and points of crossing to prevent the peripheral iris or pupil from moving forward to the cornea. The &#34;# pattern&#34; retention sutures could work well theoretically. But it was a complicated operation with 20 suture segments and 16 points of crossing times of sclerocentesis, which prolonged the operation time and increased the risk of infection. Similarly, this problem was even more severe in the report of Kemal et al.17 with &#34;Chessboard pattern&#34; barrier sutures.
Syed et al.18 and Du et al.19 suggested that improved &#34;Z pattern&#34; retention sutures could prevent silicone oil from moving to the anterior chamber in aphakic eyes with iris loss for 3-6 months. However, the points of crossing within the improved &#34;Z pattern&#34; sutures were not enough to prevent anterior synechia of the iris. Moreover, theoretically, triangle or quadrilateral sutures would be even worse than the improved &#34;Z pattern&#34; sutures.
In the current study, PSACP was invented because pentagram was a magical pattern with 15 line segments and 10 points of crossing, especially drawing with one stroke. Therefore, PSACP could not only use one 10-0 prolene suture alone across the anterior surface of the iris, forming a barrier in front of the iris by the 15 suture segments from the pentagram but also prevent the pupil from moving forward to the cornea by the central five points of crossing and fix the suture to the surface or superficial sclera by the peripheral five points of crossing. With the help of PSACP, the anterior chamber was stable with iris fixation and almost without recurrency of anterior synechia for at least 12 weeks in Case 2. Finally, Case 2 received DSAEK, and the bullous keratopathy was cured.
To our knowledge, DSAEK was one of the best surgeries to cure bullous keratopathy with minimally invasive, time-saving, and fast recovery7,20,21. The operative procedure needed adequate space basis in the anterior chamber. In Case 3, some recurrent anterior synechia resulted in an unstable anterior chamber in 24 weeks post-PSACP, suggesting that the timing of DSAEK was recommended from 4-12 weeks post-PSACP. Furthermore, Case 3 had received DSAEK jet and had also been performed with conventional anterior chamber plasty several times. If DSAEK was performed again, it might bring in more severe inflammation, restoration or fibration, and uncontrolled IOP. Therefore, PKP was finally performed. However, retention sutures were broken accidentally in PKP, and PAS was formed rapidly in 1-week post PKP, implying that PSACP prevented the iris from moving toward the cornea in such a complicated case only to some extent. Care needs to be taken of these sutures during the PKP procedure.
The limitation of this study was that it was a pilot study with only three cases with stringent inclusion and exclusion criteria. The success and benefits of PSACP with subsequent DSAEK or PKP were shown in two instances from only one hospital. Further studies in multi-center with a bigger sample size might be helpful to improve the flow chart.
In summary, iris fixation via PSACP might provide an adequate space basis for DSAEK to help cure the bullous keratopathy caused by a vanished anterior chamber or extensive anterior synechia to some extent. PSACP and DSAEK or PKP might be an effective way to cure the bullous keratopathy with extensive anterior synechia of the iris.

Extensive anterior synechia is usually observed in the eyes of patients with malignant glaucoma or primary angle-closure glaucoma after laser peripheral iridotomy or iridoplasty and after anterior segment surgery1,2,3,4,5,6. This can cause gradual reduction of the anterior chamber leading to visual dysfunction. Once extensive anterior synechia forms, the aqueous humor can enter the cornea due to endothelium decompensation, leading to bullous keratopathy7. Although a well-controlled intraocular pressure (IOP) has been obtained after lens extraction and anterior vitrectomy, the iris lens diaphragm is still soft due to atrophied and tension-free iris8. Therefore, conventional anterior chamber plasty can only temporarily form the anterior chamber9. In cases where anterior synechia is extensive, the anterior chamber disappears again and adds difficulty to the subsequent keratoplasty surgery.
Keratoplasty with iris-diaphragm intraocular lens (IOL) implantation was reported as an effective way to cure the bullous keratopathy with aniridia10,11,12,13,14. Therefore, it may be helpful to treat eyes with bullous keratopathy and extensive anterior synechia after removing the atrophied and tension-free iris. However, this idea is possibly bringing significant iatrogenic injury now and not feasible in China due to unaffordable price of such IOL.
A recent study suggested that retention or barrier sutures could prevent silicone oil from moving into the anterior chamber in aphakic eyes with iris loss15,16,17,18. Sutures enhance the surface tension of silicone oil in such situations. Therefore, the current study was conducted to investigate whether these retention or barrier sutures could improve atrophy&#39;s stress and make the iris tension-free by preventing the iris and iris lens diaphragm from approaching the cornea. The presented study was performed to explore an effective way of doing anterior chamber plasty before keratoplasty to cure the bullous keratopathy with extensive anterior synechia of the iris. The current surgery method was named &#34;Pentagram Suturing Anterior Chamber Plasty&#34; (PSACP) with a core process of iris fixation via external pentagram suturing.
Malignant glaucoma patients with bullous keratopathy and extensive anterior synechia who already underwent lens extraction, anterior vitrectomy, IOL implantation, and had a well-controlled IOP were included for the current study. Willingness to receive further keratoplasty to cure bullous keratopathy was also considered an inclusion criterion. Exclusion criteria include (1) eyes with no light perception, (2) IOP &#8805; 35 mmHg under anti-glaucoma medications, (3) eyes with infection, acute inflammation,aniridia or chronic uveitis, (4) eyes with retinal detachment, choroidal detachment, or ciliary detachment, (5) patients with uncontrolled hypertension, cardiovascular disease, cerebrovascular disease, or diabetes mellitus, (6) patients with a severe hemorrhagic tendency or mental disorders.

<table><tbody><tr><td>1% crystal violet solution</td><td>HEBEI JINZHONG PHARMACEUTIAL CO., LTD. Hebei, PRC</td><td>200709</td><td></td></tr><tr><td>10-0 prolene sutures on an STC-6 needle</td><td>Alcon Laboratories, Inc.,Sinking Spring, PA</td><td>13M4AT</td><td></td></tr><tr><td>2% lidocaine hydrochloride injection</td><td>TIANSHENG PHARMACEUTIAL GROUP CO., LTD. Hubei, PRC</td><td>42021839</td><td></td></tr><tr><td>29-gauge syringe</td><td>Becton, Dickinson and Company, NE 68949</td><td>160404</td><td></td></tr><tr><td>Anterior segment optical coherence tomography</td><td>Carl Zeiss Meditec, Inc., Dublin, CA</td><td>1000-1238</td><td></td></tr><tr><td>Balanced salt solution</td><td>Alcon Laboratories,Inc., Fort Worth,TX</td><td>7950191</td><td></td></tr><tr><td>Cohesive viscoelastic</td><td>Bausch+Lomb Inc., Shandong, CN</td><td>6.92409E+12</td><td></td></tr><tr><td>Color slit lamp photography</td><td>HAAG-STREIT AG, Gartenstadtstrasse 10, 3098 Koeniz, Switzerland</td><td>6543-2012</td><td></td></tr><tr><td>Rebound tonometer (iCare, Type TA01i)</td><td>Tiolat Oy, Finland</td><td>44</td><td></td></tr><tr><td>Sterile irrigator for single use</td><td>SHANDONG WEIGAO GROUP MEDICAL POLYMER CO., LIMITED</td><td>(01)06932992101486</td><td></td></tr><tr><td>Ultrasound biomicroscopy</td><td>Paradigm Medical Industries, Salt Lake City, UT</td><td>5290-2012</td><td></td></tr></tbody></table>

iris fixation via external pentagram suturing

Extensive anterior synechia of the iris can result in the gradual disappearance of the anterior chamber. It is one of the most common outcomes of both oculopathy and complicated post anterior segment surgery. This can impact visual function and lead to bullous keratopathy, making it one of the most complex clinical problems. Conventional anterior chamber plasty will partially create the anterior chamber, but the anterior chamber disappears again in some cases. The main reasons are: (1) the iris lens diaphragm is loose with atrophied and tension-free iris so that the aqueous humor circulation will push and squeeze the iris forward; (2) the effect of "roller" formed in the process of inflammation or restoration will change the iris structure from peripheral anterior synechia (PAS) to extensive anterior synechia again; (3) the fibration will result in synechia from iris to the cornea. In such cases, corneal endothelium deficiency can't stop the aqueous humor from entering the cornea. This results in persistent corneal edema post-conventional anterior chamber plasty, resulting in progressive rubbing and lachrymation. Therefore, anterior chamber plasty is not the first choice for patients without surgical indications of Descemet's stripping automated endothelial keratoplasty (DSAEK). However, this can be performed in patients with surgical indications who plan to receive DSAEK. A unique method of iris fixation via external pentagram suturing anterior chamber plasty (PSACP) is described here. The present technique is also compared with the conventional anterior chamber plasty. PSACP and DSAEK might be an effective way to cure the bullous keratopathy with extensive anterior synechia of the iris and disappeared anterior chamber.

Representative results from three bullous keratopathy patients with extensive anterior synechia who had a well-controlled IOP after lens extraction, anterior vitrectomy, and IOL implantation to cure malignant glaucoma are described in the study. In these cases, one received conventional anterior chamber plasty with synechia separation and penetrating keratoplasty (PKP), the other two received PSACP first, and then received Descemet&#39;s stripping automated endothelial keratoplasty (DSAEK) or PKP. Postop reaction and pigment release of all three cases were mild and faded within 4 weeks under routine anti-infection and anti-inflammatory eye drops. The prognosis of these three patients was compared on different days after 360&#176; PAS appearance with the ASOCT (1-day post-operation) or UBM (12 weeks or 24 weeks post-operation) after the anterior chamber plasty surgery.
Case 1 
A 68-year-old female was diagnosed with bullous keratopathy and extensive anterior synechia in her right eye from IOP-well-controlled (21 mmHg with four kinds of anti-glaucoma eye drops) malignant glaucoma. She already had lens extraction, anterior vitrectomy, and IOL implantation. Her right eye&#39;s best-corrected visual acuity (BCVA) was 20/4000. The iris&#39;s extensive anterior synechia was shown with ASOCT and UBM (Figure 1 and Figure 2).
She received anterior chamber plasty with synechia separation and penetrating keratoplasty (PKP) in her right eye. One-day post-surgery (Figure 4), she showed no PAS with the ASOCT (Figure 4C), and BCVA improved to 20/1000 with elevated IOP (32 mmHg). However, 12 weeks after surgery, she showed 360&#176; PAS with the UBM (Figure 4D), and BCVA decreased to 20/1600. At that moment, IOP was uncontrolled over 25 mmHg, and the bullous keratopathy reoccurred.
Case 2 
A 75-year-old female was diagnosed with bullous keratopathy and extensive anterior synechia in her left eye from IOP-well-controlled (18 mmHg with three kinds of anti-glaucoma eye drops) malignant glaucoma, which already had lens extraction, anterior vitrectomy, and IOL implantation. BCVA of her left eye was 20/1600. The disappearance of the anterior chamber was observed with ASOCT and UBM (Figure 5).
She received PSACP, where pentagram sutures were placed as a barrier in front of the anterior surface of the iris (Figure 6). No PAS was seen with ASOCT or UBM from day 1 till 12 weeks post-surgery (Figure 7). Then, she received DSAEK. On 24 weeks post-PSACP, no corneal edema was observed with ASOCT, and one clock hour PAS was demonstrated with UBM (Figure 8), with BCVA 20/66. IOP remained normal without any medication post-surgery.
Case 3 
A 69-year-old female was diagnosed with bullous keratopathy and extensive anterior synechia in her right eye from IOP-well-controlled (12 mmHg with four kinds of anti-glaucoma eye drops) malignant glaucoma, which was post lens extraction, anterior vitrectomy, IOL implantation, and DSAEK. The BCVA of her right eye was 20/1600. Extensive PAS was shown with ASOCT and UBM (Figure 9).
She received PSACP and showed 2 clock hours PAS with ASOCT on day 1 post-surgery, and she missed the 12-week-follow-up. As she showed 6 clock hours PAS with UBM in 24 weeks post-surgery (Figure 10), she received PKP. During PKP, the suture was broken accidentally and then removed. On 1-week post PKP, she showed mild edema in the cornea graft and 6 clock hours PAS with the ASOCT (Figure 11) with improved BCVA 20/400. IOP remained normal without any medication post-surgery. Unfortunately, she did not follow up.
Comparisons 
BCVA, IOP, cornea or corneal graft, anterior synechia of iris were found in these three patients preoperationally and post-operationally (Table 1 and Table 2). The prognosis of Case 2 and Case 3 was significantly better than in Case 1.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/63256/63256fig01.jpg" /> 
Figure 1: Preoperative examinations for Case 1. (A) Anterior segment photography. (B) Color slit-lamp photography. (C) Anterior segment optical coherence tomography (ASOCT). (D) Ultrasound biomicroscopy (UBM). <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/63256/63256fig02.jpg" /> 
Figure 2: Assessment of anterior synechia of iris for Case 1.&#160;(A) Anterior segment optical coherence tomography. (B) Ultrasound biomicroscopy. Red circle: anterior synechia of the iris. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/63256/63256fig03.jpg" /> 
Figure 3: Schematic representation of the procedure of PSACP for Case 3. (A) Black dashed circle: pupil; black circle: limbus; purple dashed circle: the mark of scleral puncture point; numbers and red arrow: suturing sequence and direction, both ends of the red arrow represent the exact puncture points; X: the surgical knot. (B) Red arrow: suturing position and direction. PSACP = Pentagram Suturing Anterior Chamber Plasty. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/63256/63256fig04.jpg" /> 
Figure 4: Postoperative examinations for Case 1. (A) Color slit lamp photography on day 1 post-operation. (B) Color slit lamp photography in 12 weeks post-operation. (C) Anterior segment optical coherence tomography (ASOCT) on day 1 post-operation. (D) Ultrasound biomicroscopy (UBM) in 12 weeks post-operation. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/63256/63256fig05.jpg" /> 
Figure 5: Preoperative examinations for Case 2. (A) Anterior segment photography. (B) Color slit-lamp photography. (C) Anterior segment optical coherence tomography (ASOCT). (D) Ultrasound biomicroscopy (UBM). <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/63256/63256fig06.jpg" /> 
Figure 6: Diagrammatic sketches of PSACP in operation for Case 2. (A) Color photography for sutures. (B) Blueline: pentagram sutures. (C) Anterior segment optical coherence tomography (ASOCT) on day 1 post-operation, red circle: sutures. (D) Black dashed circle: pupil; black circle: limbus; red arrow: suturing direction; X: the surgical knot. PSACP = Pentagram Suturing Anterior Chamber Plasty. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig06large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/63256/63256fig07.jpg" /> 
Figure 7: Postoperative examinations for Case 2. (A) Color slit lamp photography on day 1 post-operation. (B) Color slit lamp photography in 12 weeks post-operation. (C) Anterior segment optical coherence tomography (ASOCT) on day 1 post-operation. (D) Ultrasound biomicroscopy (UBM) in 12 weeks post-operation. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig07large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/63256/63256fig08.jpg" /> 
Figure 8: Postoperative examinations for Case 2 in 24 weeks post PSACP. (A) Color slit lamp photography, yellow arrow: sutures in the anterior chamber. (B) Color slit lamp photography, blue line: pentagram sutures. (C) Anterior segment optical coherence tomography (ASOCT) showed the cornea and endothelium graft. (D) Ultrasound biomicroscopy (UBM). PSACP = Pentagram Suturing Anterior Chamber Plasty. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig08large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/63256/63256fig09.jpg" /> 
Figure 9: Preoperative examinations for Case 3. (A) Anterior segment photography. (B) Color slit-lamp photography. (C) Anterior segment optical coherence tomography (ASOCT). (D) Ultrasound biomicroscopy (UBM). <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig09large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 10" class="xfigimg" src="/files/ftp_upload/63256/63256fig10.jpg" /> 
Figure 10: Postoperative examinations for Case 3. (A) Color slit lamp photography on day 1 post-operation. (B) Color slit lamp photography in 24 weeks post-operation. (C) Anterior segment optical coherence tomography (ASOCT) on day 1 post-operation. (D) Ultrasound biomicroscopy (UBM) in 24 weeks post-operation. Red circle: sutures. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig10large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 11" class="xfigimg" src="/files/ftp_upload/63256/63256fig11.jpg" /> 
Figure 11: Postoperative examinations for Case 3 in 25 weeks post PSACP. (A) Anterior segment photography in 1 week post PKP. (B) Color slit lamp photography in 1 week post PKP. (C) Anterior segment optical coherence tomography (ASOCT) showed the cornea and graft. (D) Anterior segment optical coherence tomography (ASOCT) showed anterior synechia of the iris. PSACP = Pentagram Suturing Anterior Chamber Plasty. PKP = penetrating keratoplasty. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/63256/63256fig11large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Case</td>
			<td>Kind of surgery</td>
			<td colspan="2">BCVA</td>
			<td colspan="2">IOP (mmHg)</td>
			<td colspan="2">Kind of anti-glaucoma eye drops</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td>Pre-op.</td>
			<td>Postop.</td>
			<td>Pre-op.</td>
			<td>Postop.*</td>
			<td>Pre-op.</td>
			<td>Postop.</td>
		</tr>
		<tr>
			<td>1</td>
			<td>CACP+PKP</td>
			<td>20/4000</td>
			<td>20/1600</td>
			<td>21</td>
			<td>25</td>
			<td>4</td>
			<td>3</td>
		</tr>
		<tr>
			<td>2</td>
			<td>PSACP, DSAEK</td>
			<td>20/1600</td>
			<td>20/66</td>
			<td>18</td>
			<td>13</td>
			<td>3</td>
			<td>0</td>
		</tr>
		<tr>
			<td>3</td>
			<td>PSACP, PKP</td>
			<td>20/1600</td>
			<td>20/400</td>
			<td>12</td>
			<td>14</td>
			<td>3</td>
			<td>0</td>
		</tr>
	</tbody>
</table>
Table 1: Visual acuity, intraocular pressure, and medications of the presented cases. BCVA = best-corrected visual acuity; IOP = intraocular pressure; Pre-op. = pre-operational; Postop. = post-operational; CACP = conventional anterior chamber plasty; PKP = penetrating keratoplasty; PSACP = Pentagram Suturing Anterior Chamber Plasty; DSAEK = Descemet&#39;s stripping automated endothelial keratoplasty.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Case</td>
			<td>Kind of surgery</td>
			<td colspan="2">Cornea/Corneal graft edema</td>
			<td colspan="2">Anterior synechia of iris (ASOCT)</td>
			<td colspan="2">Anterior synechia of iris (UBM)</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td>Pre-op.</td>
			<td>Postop.</td>
			<td>Pre-op.</td>
			<td>Postop.*</td>
			<td>Pre-op.</td>
			<td>Postop.</td>
		</tr>
		<tr>
			<td>1</td>
			<td>CACP+PKP</td>
			<td>Yes</td>
			<td>No</td>
			<td>8CH</td>
			<td>No</td>
			<td>9CH</td>
			<td>9CH</td>
		</tr>
		<tr>
			<td>2</td>
			<td>PSACP, DSAEK</td>
			<td>Yes</td>
			<td>No</td>
			<td>12CH</td>
			<td>No</td>
			<td>12CH</td>
			<td>1CH</td>
		</tr>
		<tr>
			<td>3</td>
			<td>PSACP, PKP</td>
			<td>Yes</td>
			<td>No</td>
			<td>12CH</td>
			<td>2CH</td>
			<td>12CH</td>
			<td>6CH#</td>
		</tr>
	</tbody>
</table>
Table 2: Clinical characteristics of cornea and iris of the presented cases. ASOCT = anterior segment optical coherence tomography; UBM = Ultrasound biomicroscopy; Pre-op. = preoperational; Postop. = post operational; CACP = conventional anterior chamber plasty; PKP = penetrating keratoplasty; CH = clock hour; PSACP = Pentagram Suturing Anterior Chamber Plasty; DSAEK = Descemet&#39;s stripping automated endothelial keratoplasty. * = 1 day post PSACP. # = 24 weeks post PSACP.

Watch this Scientific Journal Video about Iris Fixation via External Pentagram Suturing at JoVE.com

Iris Fixation via External Pentagram Suturing

The present protocol describes how a 10-0 polypropylene suture crosses the anterior surface of the iris, forming a pentagram to prevent both iris and pupil from moving toward the cornea. This can be combined with subsequent keratoplasty to cure bullous keratopathy with extensive anterior synechia of the iris.

Iris Fixation via External Pentagram Suturing

Extensive anterior synechia of the iris can result in the gradual disappearance of the anterior chamber. It is one of the most common outcomes of both ...

iris-fixation-via-external-pentagram-suturing

Universidad San Sebastian

Research

JoVE Journal

Medicine

1.2K Views.  Peking University Third Hospital. The present protocol describes how a 10-0 polypropylene suture crosses the anterior surface of the iris, forming a pentagram to prevent both iris and pupil from moving toward the cornea. This can be combined with subsequent keratoplasty to cure bullous keratopathy with extensive anterior synechia of the iris.

Video: Iris Fixation via External Pentagram Suturing

Permanent Cerebral Vessel Occlusion via Double Ligature and Transection

Stroke is a leading cause of death, disability, and socioeconomic loss worldwide. The majority of all strokes result from an interruption in blood flow (ischemia) 1. Middle cerebral artery (MCA) delivers a great majority of blood to the lateral surface of the cortex 2, is the most common site of human stroke 3, and ischemia within its territory can result in extensive dysfunction or death 1,4,5. Survivors of ischemic stroke often suffer loss or disruption of motor capabilities, sensory deficits, and infarct. In an effort to capture these key characteristics of stroke, and thereby develop effective treatment, a great deal of emphasis is placed upon animal models of ischemia in MCA.
Here we present a method of permanently occluding a cortical surface blood vessel. We will present this method using an example of a relevant vessel occlusion that models the most common type, location, and outcome of human stroke, permanent middle cerebral artery occlusion (pMCAO). In this model, we surgically expose MCA in the adult rat and subsequently occlude via double ligature and transection of the vessel. This pMCAO blocks the proximal cortical branch of MCA, causing ischemia in all of MCA cortical territory, a large portion of the cortex. This method of occlusion can also be used to occlude more distal portions of cortical vessels in order to achieve more focal ischemia targeting a smaller region of cortex. The primary disadvantages of pMCAO are that the surgical procedure is somewhat invasive as a small craniotomy is required to access MCA, though this results in minimal tissue damage. The primary advantages of this model, however, are: the site of occlusion is well defined, the degree of blood flow reduction is consistent, functional and neurological impairment occurs rapidly, infarct size is consistent, and the high rate of survival allows for long-term chronic assessment.

Permanent Cerebral Vessel Occlusion via Double Ligature and Transection

We describe a highly reproducible method for the permanent occlusion of a rodent major cerebral blood vessel. This technique can be accomplished with very little peripheral damage, minimal blood loss, a high rate of long-term survival, and consistent infarct volume commensurate with the human clinical population.

Stroke is a leading cause of death, disability, and socioeconomic loss worldwide. The majority of all strokes result from an interruption in blood flow ...

Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models

The mechanical environment around the healing of broken bone is very important as it determines the way the fracture will heal. Over the past decade there has been great clinical interest in improving bone healing by altering the mechanical environment through the fixation stability around the lesion. One constraint of preclinical animal research in this area is the lack of experimental control over the local mechanical environment within a large segmental defect as well as osteotomies as they heal. In this paper we report on the design and use of an external fixator to study the healing of large segmental bone defects or osteotomies. This device not only allows for controlled axial stiffness on the bone lesion as it heals, but it also enables the change of stiffness during the healing process in vivo. The conducted experiments have shown that the fixators were able to maintain a 5 mm femoral defect gap in rats in vivo during unrestricted cage activity for at least 8 weeks. Likewise, we observed no distortion or infections, including pin infections during the entire healing period. These results demonstrate that our newly developed external fixator was able to achieve reproducible and standardized stabilization, and the alteration of the mechanical environment of in vivo rat large bone defects and various size osteotomies. This confirms that the external fixation device is well suited for preclinical research investigations using a rat model in the field of bone regeneration and repair.

One constraint of preclinical research in the field of bone repair is the lack of experimental control over the local mechanical environment within a healing bone lesion. We report the design and use of an external fixator for bone repair with the ability to change fixator stiffness in vivo.

The mechanical environment around the healing of broken bone is very important as it determines the way the fracture will heal. Over the past decade there ...

Minimally Invasive Thumb-sized Pterional Craniotomy for Surgical Clip Ligation of Unruptured Anterior Circulation Aneurysms

Less invasive surgical approaches for intracranial aneurysm clipping may reduce length of hospital stay, surgical morbidity, treatment cost, and improve patient outcomes. We present our experience with a minimally invasive pterional approach for anterior circulation aneurysms performed in a major tertiary cerebrovascular center and compare the results with an aged matched dataset from the Nationwide Inpatient Sample (NIS). From August 2008 to December 2012, 22 elective aneurysm clippings on patients &#8804;55 years of age were performed by the same dual fellowship-trained cerebrovascular/endovascular neurosurgeon. One patient (4.5%) experienced transient post-operative complications. 18 of 22 patients returned for follow-up imaging and there were no recurrences through an average duration of 22 months. A search in the NIS database from 2008 to 2010, also for patients aged &#8804;55 years of age, yielded 1,341 hospitalizations for surgical clip ligation of unruptured cerebral aneurysms. Inpatient length of stay and hospital charges at our institution using the minimally invasive thumb-sized pterional technique were nearly half that of NIS (length of stay: 3.2 vs 5.7 days; hospital charges: $52,779 vs. $101,882). The minimally invasive thumb-sized pterional craniotomy allows good exposure of unruptured small and medium-sized supraclinoid anterior circulation aneurysms. Cerebrospinal fluid drainage from key subarachnoid cisterns and constant bimanual microsurgical techniques avoid the need for retractors which can cause contusions, localized venous infarctions, and post-operative cerebral edema at the retractor sites. Utilizing this set of techniques has afforded our patients with a shorter hospital stay at a lower cost compared to the national average.

Minimally invasive thumb-sized pterional craniotomy for aneurysm clipping has afforded our patients with a shorter hospital stay at a lower cost compared to the national average.

Less invasive surgical approaches for intracranial aneurysm clipping may reduce length of hospital stay, surgical morbidity, treatment cost, and improve ...

Techniques for Processing Eyes Implanted with a Retinal Prosthesis for Localized Histopathological Analysis: Part 2 Epiretinal Implants with Retinal Tacks

Retinal prostheses for the treatment of certain forms of blindness are gaining traction in clinical trials around the world with commercial devices currently entering the market. In order to evaluate the safety of these devices, in preclinical studies, reliable techniques are needed. However, the hard metal components utilised in some retinal implants are not compatible with traditional histological processes, particularly in consideration for the delicate nature of the surrounding tissue. Here we describe techniques for assessing the health of the eye directly adjacent to a retinal implant secured epiretinally with a metal tack.
Retinal prostheses feature electrode arrays in contact with eye tissue. The most commonly used location for implantation is the epiretinal location (posterior chamber of the eye), where the implant is secured to the retina with a metal tack that penetrates all the layers of the eye. Previous methods have not been able to assess the proximal ocular tissue with the tack in situ, due to the inability of traditional histological techniques to cut metal objects. Consequently, it has been difficult to assess localized damage, if present, caused by tack insertion.
Therefore, we developed a technique for visualizing the tissue around a retinal tack and implant. We have modified an established technique, used for processing and visualizing hard bony tissue around a cochlear implant, for the soft delicate tissues of the eye. We orientated and embedded the fixed eye tissue, including the implant and retinal tack, in epoxy resin, to stabilise and protect the structure of the sample. Embedded samples were then ground, polished, stained, and imaged under various magnifications at incremental depths through the sample. This technique allowed the reliable assessment of eye tissue integrity and cytoarchitecture adjacent to the metal tack.

Here we describe histological techniques for visualising ocular tissue directly adjacent to a metal epiretinal tack and retinal prosthesis.

Retinal prostheses for the treatment of certain forms of blindness are gaining traction in clinical trials around the world with commercial devices ...

Scleral Cross-linking Using Riboflavin and Ultraviolet-A Radiation for Prevention of Axial Myopia in a Rabbit Model

Myopic individuals, especially those with severe myopia, are at higher-than-normal risk of cataract, glaucoma, retinal detachment and chorioretinal abnormalities. In addition, pathological myopia is a common irreversible cause of visual impairment and blindness1-3. Our study demonstrates the effect of scleral crosslinking using riboflavin and ultraviolet-A radiation on the development of axial myopia in a rabbit model. The axial length of the eyeball was measured by A-scan ultrasound in New Zealand white rabbits aged 13 days (male and female). The eye then underwent 360&#176; conjunctival peritomy with scleral crosslinking, followed by tarsorrhaphy. Axial elongation was induced in 13 day-old New Zealand rabbits by suturing their right eye eyelids (tarsorrhaphy). The eyes were divided into quadrants, and every quadrant had two scleral irradiation zones, each with an area of 0.2 cm&#178; and a radius of 4 mm. Crosslinking was performed by dropping 0.1% dextran-free riboflavin-5-phosphate onto the irradiation zones 20 sec before ultraviolet-A irradiation and every 20 sec during the 200 sec irradiation time. UVA radiation (370 nm) was applied perpendicular to the sclera at 57 mW/cm&#178; (total UVA light dose, 57 J/cm&#178;). Tarsorrhaphies were removed on day 55, followed by repeated axial length measurements. This study demonstrates that scleral crosslinking with riboflavin and ultraviolet-A radiation effectively prevents occlusion-induced axial elongation in a rabbit model.

We demonstrate the effect of scleral crosslinking with riboflavin and UVA on an axial elongation rabbit eye. Axial elongation was induced in 13 day-old New Zealand rabbits (male and female) by suturing their right eye eyelids (tarsorrhaphy).

Myopic individuals, especially those with severe myopia, are at higher-than-normal risk of cataract, glaucoma, retinal detachment and chorioretinal ...

Subcutaneous Trigeminal Nerve Field Stimulation for Refractory Facial Pain

Chronic or neuropathic trigeminal facial pain can be challenging to treat. Neurosurgical procedures should be applied when conservative treatment fails. Neuromodulation techniques for chronic facial pain include deep brain stimulation and motor cortex stimulation, which are complex to perform. Subcutaneous nerve field stimulation is certified for chronic back pain and is the least invasive form of neuromodulation. We applied this technique to treat chronic and neuropathic trigeminal pain as an individual therapy concept. First, trial stimulation is performed. Subcutaneous leads are placed in the painful trigeminal dermatome under local anesthesia. The leads are connected to an external neurostimulator that applies constant stimulation. Patients undergo a 12 day outpatient trial to assess the effect of the stimulation. Electrodes are removed after the trial. If the patient reports pain reduction of at least 50% in intensity and/or attack frequency, a reduction in medication or increase in quality of life, permanent implantation is scheduled. New electrodes are implanted under general anesthesia and are subcutaneously tunneled to an infraclavicular internal pulse generator. Patients are able to turn stimulation on and off and to increase or decrease the stimulation amplitude as needed.
This technique represents a minimal invasive alternative to other more invasive means of neuromodulation for trigeminal pain such as motor cortex stimulation or deep brain stimulation.

Treating chronic or neuropathic facial pain can be challenging when medical or standard treatment fails. Subcutaneous nerve field stimulation is the least invasive form of neuromodulation and is used for chronic back pain. We applied this technology to treat chronic and neuropathic trigeminal facial pain.

Chronic or neuropathic trigeminal facial pain can be challenging to treat. Neurosurgical procedures should be applied when conservative treatment fails. ...

Subretinal Transplantation of Human Embryonic Stem Cell-Derived Retinal Tissue in a Feline Large Animal Model

Retinal degenerative (RD) conditions associated with photoreceptor loss such as age-related macular degeneration (AMD), retinitis pigmentosa (RP) and Leber Congenital Amaurosis (LCA) cause progressive and debilitating vision loss. There is an unmet need for therapies that can restore vision once photoreceptors have been lost. Transplantation of human pluripotent stem cell (hPSC)-derived retinal tissue (organoids) into the subretinal space of an eye with advanced RD brings retinal tissue sheets with thousands of healthy mutation-free photoreceptors and has a potential to treat most/all blinding diseases associated with photoreceptor degeneration with one approved protocol. Transplantation of fetal retinal tissue into the subretinal space of animal models and people with advanced RD has been developed successfully but cannot be used as a routine therapy due to ethical concerns and limited tissue supply. Large eye inherited retinal degeneration (IRD) animal models are valuable for developing vision restoration therapies utilizing advanced surgical approaches to transplant retinal cells/tissue into the subretinal space. The similarities in globe size, and photoreceptor distribution (e.g., presence of macula-like region area centralis) and availability of IRD models closely recapitulating human IRD would facilitate rapid translation of a promising therapy to the clinic. Presented here is a surgical technique of transplanting hPSC-derived retinal tissue into the subretinal space of a large animal model allowing assessment of this promising approach in animal models.

Presented here is a surgical technique for transplanting human pluripotent stem cell (hPSC)-derived retinal tissue into the subretinal space of a large animal model.

Retinal degenerative (RD) conditions associated with photoreceptor loss such as age-related macular degeneration (AMD), retinitis pigmentosa (RP) and ...

Neuroscience

Development of a Surgical Technique for Subretinal Implants in Rats

Retinal degeneration, such as age-related macular degeneration (AMD), is a leading cause of blindness worldwide. A myriad of approaches have been undertaken to develop regenerative medicine-based therapies for AMD, including stem cell-based therapies. Rodents as animal models for retinal degeneration are a foundation for translational research, due to the broad spectrum of strains that develop retinal degeneration diseases at different stages. However, mimicking human therapeutic delivery of subretinal implants in rodents is challenging, due to anatomical differences such as lens size and vitreous volume. This surgical protocol aims to provide a guided method for transplanting implants into the subretinal space in rats. A user-friendly comprehensive description of the critical steps has been included. This protocol has been developed as a cost-efficient surgical procedure for reproducibility across different preclinical studies in rats. Proper miniaturization of a human-sized implant is required prior to conducting the surgical experiment, which includes adjustments to the dimensions of the implant. An external approach is used instead of an intravitreal procedure to deliver the implant to the subretinal space. Using a small sharp needle, a scleral incision is performed in the temporal superior quadrant, followed by paracentesis to reduce intraocular pressure, thereby minimizing resistance during the surgical implantation. Next, a balanced salt solution (BSS) injection through the incision is carried out to achieve focal retinal detachment (RD). Lastly, insertion and visualization of the implant into the subretinal space are conducted. Post-operative assessment of the subretinal placement of the implant includes imaging by spectral domain optical coherence tomography (SD-OCT). Imaging follow-ups ascertain the subretinal stability of the implant, before the eyes are harvested and fixated for histological analysis.

The present protocol describes the scleral approach for subretinal device implantation, a feasible surgical technique for implementation in animal models of retinal diseases in research.

Retinal degeneration, such as age-related macular degeneration (AMD), is a leading cause of blindness worldwide. A myriad of approaches have been ...

Application of a New Mesh Fixation Method in Laparoscopic Incisional Hernia Repair

Laparoscopic incisional hernia repair using intraperitoneal onlay mesh (IPOM) is one of the most widely used minimally invasive methods for repairing incisional hernias. The laparoscopic IPOM involves implanting the mesh into the abdominal cavity through laparoscopy to repair an abdominal wall hernia. In the IPOM surgery, after the closure of the hernia ring, an anti-adhesion mesh is placed laparoscopically. The correct placement of this mesh is critical to the success of the method, and surgical skills are required to achieve perfect placement. If the mesh placement is not mastered properly, the operation and anesthesia time will be prolonged. In addition, improper placement of the mesh can lead to serious consequences, such as intestinal obstruction and mesh infection. A "contraposition and alignment" mesh fixation method is described in this study, which involves pre-marking the fixation position of the mesh to reduce the difficulty of mesh placement. A properly placed mesh is completely flat on the peritoneum, the edges are not curled or wrapped, and the mesh is adhered firmly such that there is no displacement after removing the pneumoperitoneum pressure. The "contraposition and alignment" mesh fixation technique offers the advantages of reliable placement of the mesh and fewer complications than other techniques, and it is easy to learn and master. It also allows for positioning the nail gun in advance based on the anatomy of the incisional hernia. This enables the use of the minimum number of nails possible while still ensuring good fixation, which can reduce the occurrence of complications and reduce the cost of surgery. Thus, the mesh fixation method described here is highly suitable for clinical applications based on the aforementioned advantages.

Presented here is a method for improving the mesh placement in laparoscopic incisional hernia repair, which can shorten the time required for mesh fixation and reduce the occurrence of postoperative chronic pain.

Laparoscopic incisional hernia repair using intraperitoneal onlay mesh (IPOM) is one of the most widely used minimally invasive methods for repairing ...

Novel PLL-AF Suture Technique for Annulus Fibrosus Repair in Lumbar Endoscopy

A Suture Technique for Ruptured Annulus Fibrosus Following Decompression Under Percutaneous Transforaminal Endoscopic Discectomy

The suture technique for a ruptured annulus fibrosus (AF) under full-endoscopy remains challenging. Direct suturing of a ruptured annular tear after full decompression has been shown to decrease the recurrence rate of lumbar disc herniation during endoscopic surgery. Traditional suture operations under endoscopy involve only simple suturing of the ruptured AF. Due to the weak and poor quality of the AF tissue around the tear portal, using this area as needle insertion points during suturing may lead to insufficient tension and a low success rate of AF closure. Currently, there is no detailed technical illustration based on video for AF tear suturing under lumbar full-endoscopy. We innovatively propose a method of covering and suturing the AF tear by pulling up the posterior longitudinal ligament (PLL) under lumbar endoscopy and using three stitches (PLL-AF suture technique). The patient who received the novel suture technique achieved satisfactory results. Six months after the operation, lumbar MRI showed no evidence of recurrence in the outpatient clinic.

Author Spotlight: Development and Application of a Novel Suture Technique for Annular Fibrosus Repair in Percutaneous Transforaminal Endoscopic Discectomy

This protocol describes an innovative suture technique for ruptured annular fibrosus during percutaneous transforaminal endoscopic discectomy.

The suture technique for a ruptured annulus fibrosus (AF) under full-endoscopy remains challenging. Direct suturing of a ruptured annular tear after full ...

Iris Fixation via External Pentagram Suturing

Summary

Explore More Videos

Chapters in this video

Permanent Cerebral Vessel Occlusion via Double Ligature and Transection

Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models

Minimally Invasive Thumb-sized Pterional Craniotomy for Surgical Clip Ligation of Unruptured Anterior Circulation Aneurysms

Techniques for Processing Eyes Implanted with a Retinal Prosthesis for Localized Histopathological Analysis: Part 2 Epiretinal Implants with Retinal Tacks

Scleral Cross-linking Using Riboflavin and Ultraviolet-A Radiation for Prevention of Axial Myopia in a Rabbit Model

Subcutaneous Trigeminal Nerve Field Stimulation for Refractory Facial Pain

Subretinal Transplantation of Human Embryonic Stem Cell-Derived Retinal Tissue in a Feline Large Animal Model

Development of a Surgical Technique for Subretinal Implants in Rats

Application of a New Mesh Fixation Method in Laparoscopic Incisional Hernia Repair

A Suture Technique for Ruptured Annulus Fibrosus Following Decompression Under Percutaneous Transforaminal Endoscopic Discectomy