Handshake riveting flanged technique an option for intrascleral IOL fixation
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The flanged double-needle technique has been described by Yamane and colleagues for secured fixation of an IOL transsclerally. Threading of the trailing haptic and its externalization are often met with surgical challenges, and various modifications have been described for atraumatic and easy externalization of the IOL haptics. The handshake technique has been described for glued IOL fixation to facilitate trailing haptic externalization. The riveting technique for iridodialysis repair has been described by Kusaka and colleagues, wherein the 6-0-Prolene suture is passed through the peripheral iris tissue to the scleral wall groove and the flanged and riveted ends of the suture hold the peripheral iris tissue in place. The riveted ends are achieved by heating the suture end with a low-temp cautery and then pressing the flanged bulb to make it more flat and wide.
We put forward the handshake technique with riveting method of flange (HRF) creation in Yamane’s method of secondary IOL fixation, which helps to securely fix the IOL haptics. The HRF technique is independent of the availability of a thin-walled 30-gauge needle and can be performed with a widely available 26-gauge needle.
Surgical technique
Source: Priya Narang, MS, and Amar Agarwal, MS, FRCS, FRCOphth
As in Yamane’s method, the scleral marks for sclerotomy are placed 180° apart and 2 mm from the limbus. Two additional marks are placed parallel to the limbus at a distance of 2 mm along the previous marks to serve as a reference mark for introducing the needle (Figure 1). A 26-gauge needle (25 mm length) is bent approximately at one-fourth in length (from the hub) with the bevel facing upward and is used to make an angled sclerotomy transsclerally at a distance of 2 mm from the limbus (Figure 2a).
A three-piece foldable IOL (Sensar AR40, Johnson & Johnson Vision) is loaded, and the tip of the leading haptic is slightly extruded from the cartridge. The cartridge loaded with the IOL is introduced from the corneal incision, and the tip of the leading haptic is directly threaded and placed into the lumen of the 26-gauge needle (Figure 2b). The surgical technician advances the twist-type plunger while the surgeon holds the shaft of the injector until the IOL unfolds completely. The tip of the trailing haptic is left extruded at the corneal incision (Figure 2c). The needle is withdrawn and eventually externalizes the leading haptic along with it. The tip of the leading haptic is flanged with low-temp cautery (Accu-Temp cautery, Beaver-Visitec). Sequentially, the flanged portion of the haptic is compressed with a needle holder and is flattened. The flanged-riveted haptic is then pushed into the scleral wall (Figures 3a to 3d). This helps the IOL to realign itself into the initial position wherein the trailing haptic lies at the corneal incision as it overcomes the initial counterclockwise movement.
The trailing haptic is held with end-opening forceps and introduced inside the anterior chamber. Another pair of end-opening forceps is introduced from the paracentesis incision, and the trailing haptic is transferred from the right hand to the left hand as in the handshake technique (Figures 4a to 4d). The right-hand forceps are withdrawn, and the surgeon then holds a 26-gauge needle that is introduced transsclerally. The tip of the trailing haptic is threaded into the lumen of the 26-gauge needle, and the needle is withdrawn along with the haptic (Figures 4e and 4f). The externalized haptic end is flanged and flattened (Figure 5). The trailing haptic is then pushed back, and it lies in the transscleral plane.
Postoperatively, the IOL was well centered (Figure 6), and anterior segment OCT demonstrated a well-tucked haptic into the scleral wall (Figure 7).
Discussion
IOLs with polyvinylidene fluoride (PVDF) haptics are recommended for performing the double-flanged technique due to increased resilience of the haptic material. Due to nonavailability of the CT Lucia IOL (CT Lucia 602, Carl Zeiss Meditec), the authors employed the Sensar three-piece (AR40) IOL, which has PMMA haptics.
Turnbull and colleagues reported the use of a regular 30-gauge needle to be associated with a high risk for haptic damage and said that a 30-gauge needle with an ultrathin wall should be used because it has the same external dimension with a larger internal diameter as compared with a regular 30-gauge needle. Availability of a thin-walled 30-gauge needle is a concern in many parts of the world. Preoperatively, we did a trial in which a 30-gauge needle was used and an attempt to thread the haptic of Sensar three-piece IOL was attempted. The PMMA haptic did not enter the lumen of the 30-gauge needle whereas it could be threaded efficiently into the 26-gauge needle (Figure 8) and, with slight manipulation, into a 27-gauge needle. Therefore, the authors employed a 26-gauge needle for this surgical technique.
As there are two variants of 26-gauge needles available commercially, the needle with 25 mm length is recommended as compared with the shorter variant (12 mm length) due to better accessibility of the needle for intraocular maneuvers. The diameter of the inner lumen of a regular 30-gauge needle is 0.14 mm, of a thin-walled 30-gauge needle is 0.20 mm, of a 27-gauge needle is 0.21 mm and of a 26-gauge needle is 0.26 mm. The diameter of the haptic of most three-piece IOLs ranges from 0.14 mm to 0.17 mm. Therefore, it is apt to thread the PMMA haptic either in a 27-gauge or 26-gauge needle to facilitate the procedure.
Kelkar and colleagues reported the use of a 27-gauge needle, although they recommended using a 26-gauge needle for easy threading of the haptic. Turnbull and colleagues reported that when 27-gauge needles were used to externalize the haptics, the tract created by the larger-bore needle was too wide to prevent slippage of the flanged haptic. Yamane and colleagues recommended that with the use of the 27-gauge needle, adequate flange creation should be ensured. In the HRF technique, riveting and flattening the flange widen the diameter of the flange much more than is normally achieved in the Yamane technique, thereby preventing haptic slippage.
Externalization of the trailing haptic is a major concern for surgeons while learning the double-needle technique. The handshake technique has been described as transfer of haptics from one hand to the other until the tip of the haptic is held for externalization in glued IOL fixation and easy externalization of the trailing haptic can be achieved. Performing the handshake technique for the trailing haptic in the HRF method is further simplified as the leading haptic is externalized, is flanged-riveted and reverts back to its original position. The trailing haptic does not rotate and move out of view. On the other hand, it lies in its original axis and is clearly visualized. When the leading haptic is exteriorized, the trailing haptic rotates counterclockwise, but after the flange is made and riveted and when the haptic is tucked into the scleral wall, it again rotates in the clockwise direction, placing the trailing haptic close to the corneal incision. Thus, the docking procedure for the trailing haptic is comparatively simplified due to appropriate positioning of the haptic, and it is further simplified by performing the handshake technique, thereby offsetting any clinical or surgical component that might pose a challenge or difficulty in performing the technique. Kim suggested performing a handshake for the trailing haptic, but with the limitation that while doing so, it needs a third hand to hold the needle. Flanging and riveting the leading haptic in the HRF method overcome this limitation.
Various surgical modifications have been described to facilitate the trailing haptic externalization. Ganne and colleagues described threading the leading haptic with a silicone stopper to avoid intraocular haptic rebound and for the trailing haptic to be maneuvered easily, although it requires an additional surgical device. Hwang and colleagues reported a single needle technique that eliminated the use of two needles in the surgical procedure. They also reported creation of the flange of the leading haptic followed by the trailing haptic. Although Hwang and colleagues performed the technique with a thin-walled 30-gauge needle, the IOL used was not specified.
The low-temp cautery helps to create an optimal flange as described by Yamane and colleagues. In our method, the flange was compressed with the needle holder to flatten it. The riveted flange does not slip through the track created with a 26-gauge needle but is embedded in the scleral wall, as demonstrated in the anterior segment OCT image. As the flange is wide, the chances of haptic slippage are almost nullified, although it is essential to state that the flange should be buried in the scleral wall and not lie completely beneath the conjunctiva. The riveted flanged end of the IOL haptic acts as an anchor to hold the haptic to the scleral bed and would theoretically prevent any spontaneous slippage of the haptic into the comparatively larger needle tract of a 26-gauge needle as compared with a 30-gauge needle tract. Yamane and colleagues recommended that in such instances the entry of the scleral tunnel should be enlarged with the needle to ensure adequate insertion of the flange into the sclera. In all the cases, the authors did not encounter the need to enlarge the scleral entry, and the riveted flanges were adequately buried into the scleral wall probably due to the fact that the 26-gauge needle tract was adequate to accommodate them. Although the authors employed a Sensar three-piece IOL for all the cases undergoing the HRF technique, three-piece IOLs from other companies can also be employed for the surgery.
To summarize, the handshake technique enhances maneuverability of the trailing haptic, and the comparatively wider bore of the intrascleral tract created with a 26-gauge needle is compensated with the wider flange that is riveted and prevents haptic slippage. The main advantage of the HRF technique is its applicability in case of nonavailability of a thin-walled 30-gauge needle and a specified three-piece IOL with PVDF haptics. The technique can still be performed and adopted by all surgeons, and the results can be optimized. The HRF technique bypasses the challenges associated with difficulty in threading and maneuvering the haptics and haptic externalization, and it also overcomes the limitation of using a specific thin-walled needle along with PVDF haptic IOLs.
- References:
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- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, is director of Dr. Agarwal’s Eye Hospital and Eye Research Centre. Agarwal is the author of several books published by SLACK Incorporated, publisher of Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at 19 Cathedral Road, Chennai 600 086, India; email: aehl19c@gmail.com; website: www.dragarwal.com.
- Priya Narang, MS, can be reached at Narang Eye Care & Laser Centre, Ahmedabad, India; email: narangpriya19@gmail.com.
Disclosures: Agarwal and Narang report no relevant financial disclosures.