Shandong Medical and Health Science and Technology Development Plan Project (202207020806)

The following protocol was reviewed and approved by the Ethics Committee of the Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine (Grant No. HEC-KS-2020002KY), and was strictly adhered to the Declaration of Helsinki. All patients signed an informed consent form.
1. Patient selection
NOTE: 20 patients (38 eyes) with presbyopia treated by excimer laser monocular multifocal bi-aspheric ablation were admitted to the Department of Refractive Surgery of the Eye Hospital Affiliated with Shandong University of Traditional Chinese Medicine. Baseline and follow-up examinations were performed.
<ol>
	<li>Inclusion criteria
	<ol>
		<li>Include patients between 40-55 years of age diagnosed with presbyopia in both eyes.</li>
		<li>Include patients with a sphere range of -1.00 D to -8.00 D and a cylinder range &#8805; -4.00 D.</li>
		<li>Include patients with an ADD range of +1.25D to +2.50 D.</li>
		<li>Include patients with best corrected distance visual acuity &#8805; 0.8 and best corrected near visual acuity 40 cm &#62; J2.</li>
		<li>Incule patients whose monocular test tolerates anisometropia of at least 1 D.</li>
		<li>Include patients with the diameter of the photopic pupil of 2.5-3.5 mm and dark pupil &#62; 4.5 mm.</li>
		<li>Include patients whose corneal spherical aberration at 6 mm &#62; 0.0 &#181;m and the root mean square value (RMS) of corneal higher-order aberration (HOA) at 6 mm &#60; 0.5 &#181;m.</li>
	</ol>
	</li>
	<li>Exclusion criteria
	<ol>
		<li>Exclude patients who have active inflammation or infection of the eyes.</li>
		<li>Exclude patients with abnormal corneal topography and biomechanical examination before operation. Exclude if corneal stroma thickness &#60; 300 &#181;m after ablation and preoperative central corneal thickness &#60; 470 &#181;m.</li>
		<li>Exclude patients with pupil offset &#8805; 0.7 mm.</li>
		<li>Exclude patients with other eye diseases affecting vision except refractive error, history of ophthalmic surgery (including laser corneal refractive surgery), history of trauma, etc.</li>
		<li>Exclude patients with anxiety, depression, and other mental states and with high requirements for postoperative visual quality and vision.</li>
	</ol>
	</li>
</ol>
2. Preoperative preparation
<ol>
	<li>Examine the patient before refractive surgery.
	<ol>
		<li>Identify the dominant eye using a Hole test.
		<ol>
			<li>Adjust both eyes to the best corrected visual acuity (BCVA),straighten the arms. Cross the thumbs and index fingers to form a small triangle, and look at the bow 2.5 m in front.</li>
			<li>Cover the left eye; if the bow is still visible, the dominant eye is the right eye. If the bow is not visible, the dominant eye is the left eye.</li>
		</ol>
		</li>
		<li>Calculate and adjust ADD.
		<ol>
			<li>Select experimental ADD. Calculate it by the formula, ADD =15 - age/4.</li>
			<li>Adjust ADD. Mesaure negative relative accommodation (NRA) and positive relative accommodation (PRA) on an experimental ADD basis. Divide the algebraic sum of NRA and PRA by two plus experimental ADD.</li>
			<li>Determine the final prescription. For individuals whose reading distance is greater than 40 cm, reduce +0.25 D; For patients with reading distance less than 40 cm, add +0.25 D, make several subtle adjustments and try to confirm the final prescription, so that the patient&#39;s vision is clear and comfortable.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Perform other preoperative examinations.
	<ol>
		<li>Include slit-lamp microscopy, comparative sensitivity function, Sirius 3D anterior segment, and corneal aberration analyzer to measure corneal topographic, corneal aberration, and pupil size in light, medium, and dark environments.</li>
		<li>Measure the corneal morphology by three-dimensional anterior segment analysis and assess corneal biomechanics using a corneal visual biomechanics analyzer.Finally, perform cycloplegic refraction and fundus examination.</li>
	</ol>
	</li>
	<li>Plan the surgical design.
	<ol>
		<li>Use the anterior segment and corneal aberration analyzer, with the Aberration Free (AF) mode selected for the dominant eye to eliminate aberrations andtarget refraction of 0.</li>
		<li>The non-dominant eye was&#160;selected as the monocular mode, and according&#160;to the measured pupil size, the optical zone was&#160;set to 6.2-6.7 mm, the distant target was -0.89&#160;D, and the central 3 mm area was introduced&#160;into ADD&#160;(depending on the patient, up to-2.50 D).</li>
	</ol>
	</li>
	<li>Provide preoperative medications.
	<ol>
		<li>Provide preoperative medications 3 days before the operation: levofloxacin hydrochloride eye drops 3 times a day and hydroxoglycoside eye drops 4 times a day.</li>
	</ol>
	</li>
</ol>
3. Surgical procedure
<ol>
	<li>Flush and disinfect the eye.
	<ol>
		<li>Ask the patient to open his eyes and look upward. Rinse the conjunctiva sac with 0.9% normal saline.</li>
		<li>Disinfect the skin within 6 cm around the eyelid center with a skin disinfectant. Apply promethacaine hydrochloride eye drops for ocular surface anesthesia every 10 min, a total of 2 times.</li>
	</ol>
	</li>
	<li>Place the patient supine and put the head in the right position. Lay the surgical towel, expose the surgical eye, and drop artificial tears to moisten the ocular surface. Stick a transparent dressing frame, open the eyelid fissure to fully expose the cornea, and wipe the cornea with a wet sterile sponge (Figure 1).</li>
	<li>Use the femtosecond laser system to create the corneal flap (Figure 2). Attach the negative pressure suction ring to the laser emission window and treatment control panel.</li>
	<li>Select the flap mode and start the treatment steps according to the treatment program on the treatment screen. Ask the patient to look at the green light. Use the operating microscope and operating table joystick to align accurately.</li>
	<li>During alignment, make the watermark just in the center of the contact lens on the negative pressure ring and let it reach about 80%-90%.</li>
	<li>Start the negative pressure suction until the cornea completely adheres to the contact surface of the negative pressure ring. Hear Section On for the end of negative pressure suction, and hear Ready to prepare for the next step.</li>
	<li>Depress the pedal to start ablation, and urge the patient to stare at the green gaze light. Corneal stromal flap parameters: thickness: 100 &#181;m; diameter: 8.1 mm; hinge angle: 90&#176;;intrastromal scan laser energy: 125 nJ; edge cutting scan laser energy: 125 nJ. Once the corneal flap production is completed, release the pedal, disengage the negative pressure suction, and remove the negative pressure suction ring.</li>
	<li>Replace the negative pressure suction head and repeat steps 3.2-3.7 to treat the other eye.</li>
	<li>Guide the patient to the excimer laser surgical bed and place the patient supine. Lay the surgical towel, stick a transparent dressing frame, and open the eyelid fissure to fully expose the cornea. Rinse the corneas with a balanced saline solution and accurately align them with the aid of an operating microscope.</li>
	<li>Separate the corneal flap using a corneal flap separator, insert a light separation from the lateral incision near the hinge, and carefully separate the flap from the corneal stroma in the opposite direction of the pedicle until the corneal flap is completely opened, exposing the stroma. Finally, use the disposable sterile medical sponge to dry surface moisture.</li>
	<li>Use the excimer laser to ablate the corneal stroma (Figure 3). Verify the patient&#39;s information and cut using the excimer laser according to the surgical design. Ask the patient to stare at the gaze light, keep the eyes aligned with the laser, and center the corneal apex to select the corneal apex for the stromal ablation.</li>
	<li>At the end of the treatment, rinse the stroma with a compound electrolyte intraocular irrigating solution. Reset the corneal flap (Figure 4), and apply 0.3% tobramycin and dexamethasone eye drops. Observe the corneal reset under a slit lamp. Repeat step 3.8-3.9 to isolate the other corneal flap and perform stromal ablation.</li>
	<li>Guide the patient out of the operating table, put on a sterile eye mask, and ask the patient for a review the next day after the operation.</li>
</ol>

Excimer Laser Multifocal Double Aspheric Ablation for Presbyopia Correction

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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Refractive+lens+exchange+versus+phakic+intraocular+lenses.">Refractive lens exchange versus phakic intraocular lenses.</a> Curr Opin Ophthalmol. 23 (1), 54-61 (2012).</li><li>Soler Tom&#225;s, J. R., Fuentes-P&#225;ez, G., Burillo, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Symmetrical+versus+asymmetrical+PresbyLASIK:+Results+after+18+months+and+patient+satisfaction.">Symmetrical versus asymmetrical PresbyLASIK: Results after 18 months and patient satisfaction.</a> Cornea. 34 (6), 651-657 (2015).</li><li>Shetty, R., Brar, S., Sharma, M., Dadachanji, Z., Lalgudi, V. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PresbyLASIK:+A+review+of+PresbyMAX,+Supracor,+and+laser+blended+vision:+Principles,+planning,+and+outcomes.">PresbyLASIK: A review of PresbyMAX, Supracor, and laser blended vision: Principles, planning, and outcomes.</a> Indian J Ophthalmol. 68 (12), 2723-2731 (2020).</li><li>Pinelli, R., Ortiz, D., Simonetto, A., Bacchi, C., Sala, E., Ali&#243;, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correction+of+presbyopia+in+hyperopia+with+a+center-distance,+paracentral-near+technique+using+the+Technolas+217z+platform.">Correction of presbyopia in hyperopia with a center-distance, paracentral-near technique using the Technolas 217z platform.</a> J Refract Surg. 24 (5), 494-500 (2008).</li><li>Ali&#243;, J. L., Chaubard, J. J., Caliz, A., Sala, E., Patel, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correction+of+presbyopia+by+technovision+central+multifocal+LASIK+(presbyLASIK).">Correction of presbyopia by technovision central multifocal LASIK (presbyLASIK).</a> J Refract Surg. 22 (5), 453-460 (2006).</li><li>Vargas-Fragoso, V., Ali&#243;, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corneal+compensation+of+presbyopia:+PresbyLASIK:+An+updated+review.">Corneal compensation of presbyopia: PresbyLASIK: An updated review.</a> Eye Vis (Lond). 4, 11 (2017).</li><li>Pallikaris, I. G., Panagopoulou, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PresbyLASIK+approach+for+the+correction+of+presbyopia.">PresbyLASIK approach for the correction of presbyopia.</a> Curr Opin Ophthalmol. 26 (4), 265-272 (2015).</li><li>Ryu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presbyopia+correction+using+the+monocular+bi-aspheric+ablation+profile+in+myopic+eyes.">Presbyopia correction using the monocular bi-aspheric ablation profile in myopic eyes.</a> J Cataract Refract Surg. 49 (1), 69-75 (2023).</li><li>Fu, D., Zhao, J., Zeng, L., Zhou, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One+year+outcome+and+satisfaction+of+presbyopia+correction+using+the+PresbyMAX&#174;+monocular+ablation+profile.">One year outcome and satisfaction of presbyopia correction using the PresbyMAX&#174; monocular ablation profile.</a> Front Med (Lausanne). 7, 589275 (2020).</li><li>Fu, D., Zhao, J., Zhou, X. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Objective+optical+quality+and+visual+outcomes+after+the+PresbyMAX+monocular+ablation+profile.">Objective optical quality and visual outcomes after the PresbyMAX monocular ablation profile.</a> Int J Ophthalmol. 13 (7), 1060-1065 (2020).</li><li>Braun, E. H., Lee, J., Steinert, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monovision+in+LASIK.">Monovision in LASIK.</a> Ophthalmology. 115 (7), 1196-1202 (2008).</li><li>Kohnen, T., B&#246;hm, M., Herzog, M., Hemkeppler, E., Petermann, K., Lwowski, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Near+visual+acuity+and+patient-reported+outcomes+in+presbyopic+patients+after+bilateral+multifocal+aspheric+laser+in+situ+keratomileusis+excimer+laser+surgery.">Near visual acuity and patient-reported outcomes in presbyopic patients after bilateral multifocal aspheric laser in situ keratomileusis excimer laser surgery.</a> J Cataract Refract Surg. 46 (7), 944-952 (2020).</li><li>Uthoff, D., P&#246;lzl, M., Hepper, D., Holland, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+method+of+cornea+modulation+with+excimer+laser+for+simultaneous+correction+of+presbyopia+and+ametropia.">A new method of cornea modulation with excimer laser for simultaneous correction of presbyopia and ametropia.</a> Graefes Arch Clin Exp Ophthalmol. 250 (11), 1649-1661 (2012).</li><li>Baudu, P., Penin, F., Mosquera Arba, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uncorrected+binocular+performance+after+biaspheric+ablation+profile+for+presbyopic+corneal+treatment+using+AMARIS+with+the+PresbyMAX+module.">Uncorrected binocular performance after biaspheric ablation profile for presbyopic corneal treatment using AMARIS with the PresbyMAX module.</a> Am J Ophthalmol. 155 (4), 636-647 (2013).</li><li>Luger, M. H., McAlinden, C., Buckhurst, P. J., Wolffsohn, J. S., Verma, S., Arba-Mosquera, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presbyopic+LASIK+using+hybrid+bi-aspheric+micro-monovision+ablation+profile+for+presbyopic+corneal+treatments.">Presbyopic LASIK using hybrid bi-aspheric micro-monovision ablation profile for presbyopic corneal treatments.</a> Am J Ophthalmol. 160 (3), 493-505 (2015).</li><li>Luger, M. H., Ewering, T., Arba-Mosquera, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-year+experience+in+presbyopia+correction+with+biaspheric+multifocal+central+presbyopia+laser+in+situ+keratomileusis.">One-year experience in presbyopia correction with biaspheric multifocal central presbyopia laser in situ keratomileusis.</a> Cornea. 32 (5), 644-652 (2013).</li><li>Chan, T. C., Kwok, P. S., Jhanji, V., Woo, V. C., Ng, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presbyopic+correction+using+monocular+bi-aspheric+ablation+profile+(PresbyMAX)+in+hyperopic+eyes:+1-year+outcomes.">Presbyopic correction using monocular bi-aspheric ablation profile (PresbyMAX) in hyperopic eyes: 1-year outcomes.</a> J Refract Surg. 33 (1), 37-43 (2017).</li><li>El Danasoury, A. M., Gamaly, T. O., Hantera, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multizone+LASIK+with+peripheral+near+zone+for+correction+of+presbyopia+in+myopic+and+hyperopic+eyes:+1-year+results.">Multizone LASIK with peripheral near zone for correction of presbyopia in myopic and hyperopic eyes: 1-year results.</a> J Refract Surg. 25 (3), 296-305 (2009).</li><li>Yebra-Pimentel, E., Gonz&#225;lez-J&#233;ijome, J. 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All authors have nothing to disclose.

Currently, there are limited effective methods for restoring ocular accommodation, making presbyopia a prominent area of research in refractive surgery. The bi-aspheric ablation profile, a widely recognized clinical modality for presbyopia correction, has shown favorable safety and efficacy with satisfactory postoperative outcomes15,16,17. However, there is a paucity of studies focusing on the monocular mode. In this study, we p...

Presbyopia is an age-related reduction in amplitude of accommodation leading to loss of near vision due to the loss of function of the lens and ciliary muscle1. The global population of presbyopes is projected to exceed 2 billion by 2030, with uncorrected and undercorrected presbyopia affecting socio-economic development2. Correction of presbyopia includes lens correction, surgical approaches, and medication. Corneal surgery is one of the main forms of corneal surgery to correct presbyopia because of its less invasive nature, fewer complications, and faster recovery3.
Ruiz introduced Presby laser-assisted in situ keratomileusis (LASIK) in 1996, which ablates the cornea into a multifocal pattern and increases the negative SA to achieve simultaneous near and distance vision4,5. Depending on the proximity area, Presby LASIK can be categorized into peripheral model6 (peripheral area for near vision and central area for distance vision) and central model7(peripheral area for distance vision and central area for near vision)8,9. The monocular bi-aspheric ablation profile is a hybrid Presby LASIK that combines the advantages of multiple programs, including micro-monocular vision, bi-aspheric, and multifocal. The dominant eye is completely corrected for distance vision, the central zone of the non-dominant eye retains approximately -0.89D of refraction for near vision, the peripheral cornea is ablated for distance vision, and the range of near addition (ADD) is between +1.25D to 2.50D, and aspheric cutting is used in both the central and peripheral zones10,11.
Compared with the previous monovision LASIK, the multifocal morphology of the non-dominant eye after the monocular bi-aspheric ablation profile reduces the anisometropia between the two eyes. The negative increase of SA introduces the depth of focus, which can better improve near vision and, at the same time, improve the intermediate vision, reduce the impact on stereopsis, and improve the patient&#39;s acceptance and satisfaction11,12,13. The monocular mode will lead to complete correction of the dominant eye, which can achieve the fastest postoperative clear full vision, reduce the risk of UDVA decline, and is more suitable for patients with presbyopia who have the same requirements for UDVA and UIVA, while other algorithms are multifocal in both eyes, which need more time for adaptation after surgery and have the risk of UDVA decline14,15,16. This article describes the detailed surgical steps of excimer laser multifocal double aspheric ablation mode as a surgical guide.

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			<td>6941684920076</td>
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			<td>6924090700180</td>
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			<td>Alcon-Couvreur</td>
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			<td>SCHWIND Cutom Ablation Manager for Amaris</td>
			<td>Consorzio Servizi Ortopedici,Turin,IT</td>
			<td>N/A</td>
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			<td>Consorzio Servizi Ortopedici,Turin,IT</td>
			<td>YM0020207&#160;</td>
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</table>

correction of presbyopia by monocular bi-aspheric ablation profile

The study aims to evaluate visual acuity and objective visual quality before and after the monocular bi-aspheric ablation profile for correction of presbyopia surgery. This prospective self-control study included 20 cases and 38 eyes of patients who underwent monocular bi-aspheric ablation profile correction of myopia with presbyopia at the Eye Hospital of Shandong University of Traditional Chinese Medicine from January 2023 to January 2024. These patients were selected for observation, and each patient's preoperative and postoperative uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), spherical aberration (SA) (within 6 mm), horizontal and vertical coma (within 6 mm), and corneal aspheric index (Q-value) (within 6 mm) were evaluated. Statistical data analysis was performed at different time points before and after the operation. There were statistically significant differences in UDVA between dominant and non-dominant eyes before and after surgery (Z = -3.784, p &lt; 0.001; Z = -3.817, p &lt; 0.001). Post-operatively, 90% of the non-dominant eyes achieved UNVA of J1 and above, and 95% of the bilateral eyes achieved UNVA of J1 and above. Significant differences were found in the SA of the dominant eyes, which showed a positive increase (Z= -3.784, p &lt; 0.001); however, compared with the dominant eye, the SA of the non-dominant eye was negatively increased, but the difference was not statistically significant (p = 0.08). There was a significant difference in the vertical coma of the dominant eye before and after the operation, but there was no significant difference in non-dominant eyes. There was no significant difference in the change of binocular horizontal coma before and after the operation. There were significant changes in the Q value of both eyes before and after the operation (Z = -3.923, p &lt; 0.001; Z = -3.51, p &lt; 0.001). After the monocular bi-aspheric ablation profile, the cornea of the non-dominant eye showed a prolate shape, negative SA increased, and the UDVA and UNVA improved after the operation.

A total of 20 patients who underwent the monocular bi-aspheric ablation profile for correction of presbyopia were analyzed in this study. The preoperative age of the patients was 47 (&#177; 3.36) years, and the preoperative spherical equivalent (SE) of the dominant and non-dominant eyes were -4.47 D (&#177; 2.16) D and -4.34 D (&#177;2.09 D), respectively. All surgeries were completed with no postoperative complications.
Visual acuity results 
There was no significant dif...

Author Spotlight: Advancements in Refractive Surgical Correction for Presbyopia and Exploring Postoperative Visual Acuity

This article provides a step-by-step guide to correcting presbyopia with a monocular bi-aspheric ablation profile.

Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile

The study aims to evaluate visual acuity and objective visual quality before and after the monocular bi-aspheric ablation profile for correction of ...

correction-of-presbyopia-by-monocular-bi-aspheric-ablation-profile

Research

JoVE Journal

Medicine

316 Views.  Shandong University of Traditional Chinese Medicine. This article provides a step-by-step guide to correcting presbyopia with a monocular bi-aspheric ablation profile.

Video: Author Spotlight: Advancements in Refractive Surgical Correction for Presbyopia and Exploring Postoperative Visual Acuity

Thermal Ablation for the Treatment of Abdominal Tumors

Percutaneous thermal ablation is an emerging treatment option for many tumors of the abdomen not amenable to conventional treatments. During a thermal ablation procedure, a thin applicator is guided into the target tumor under imaging guidance. Energy is then applied to the tissue until temperatures rise to cytotoxic levels (50-60 &deg;C). Various energy sources are available to heat biological tissues, including radiofrequency (RF) electrical current, microwaves, laser light and ultrasonic waves. Of these, RF and microwave ablation are most commonly used worldwide.
During RF ablation, alternating electrical current (~500 kHz) produces resistive heating around the interstitial electrode. Skin surface electrodes (ground pads) are used to complete the electrical circuit. RF ablation has been in use for nearly 20 years, with good results for local tumor control, extended survival and low complication rates1,2. Recent studies suggest RF ablation may be a first-line treatment option for small hepatocellular carcinoma and renal-cell carcinoma3-5. However, RF heating is hampered by local blood flow and high electrical impedance tissues (eg, lung, bone, desiccated or charred tissue)6,7. Microwaves may alleviate some of these problems by producing faster, volumetric heating8-10. To create larger or conformal ablations, multiple microwave antennas can be used simultaneously while RF electrodes require sequential operation, which limits their efficiency. Early experiences with microwave systems suggest efficacy and safety similar to, or better than RF devices11-13.
Alternatively, cryoablation freezes the target tissues to lethal levels (-20 to -40 &deg;C). Percutaneous cryoablation has been shown to be effective against RCC and many metastatic tumors, particularly colorectal cancer, in the liver14-16. Cryoablation may also be associated with less post-procedure pain and faster recovery for some indications17. Cryoablation is often contraindicated for primary liver cancer due to underlying coagulopathy and associated bleeding risks frequently seen in cirrhotic patients. In addition, sudden release of tumor cellular contents when the frozen tissue thaws can lead to a potentially serious condition known as cryoshock 16.
Thermal tumor ablation can be performed at open surgery, laparoscopy or using a percutaneous approach. When performed percutaneously, the ablation procedure relies on imaging for diagnosis, planning, applicator guidance, treatment monitoring and follow-up. Ultrasound is the most popular modality for guidance and treatment monitoring worldwide, but computed tomography (CT) and magnetic resonance imaging (MRI) are commonly used as well. Contrast-enhanced CT or MRI are typically employed for diagnosis and follow-up imaging.

A thermal tumor ablation procedure is described. The entire procedure is detailed, including pretreatment planning and imaging studies, anesthesia, adjuvant techniques to facilitate a percutaneous approach, imaging guidance of the ablation device to the tumor, thermal treatment, post-treatment care and follow-up.

Percutaneous thermal ablation is an emerging treatment option for many tumors of the abdomen not amenable to conventional treatments. During a thermal ...

Remote Magnetic Navigation for Accurate, Real-time Catheter Positioning and Ablation in Cardiac Electrophysiology Procedures

New remote navigation systems have been developed to improve current limitations of conventional manually guided catheter ablation in complex cardiac substrates such as left atrial flutter. This protocol describes all the clinical and invasive interventional steps performed during a human electrophysiological study and ablation to assess the accuracy, safety and real-time navigation of the Catheter Guidance, Control and Imaging (CGCI) system. Patients who underwent ablation of a right or left atrium flutter substrate were included. Specifically, data from three left atrial flutter and two counterclockwise right atrial flutter procedures are shown in this report. One representative left atrial flutter procedure is shown in the movie. This system is based on eight coil-core electromagnets, which generate a dynamic magnetic field focused on the heart. Remote navigation by rapid changes (msec) in the magnetic field magnitude and a very flexible magnetized catheter allow real-time closed-loop integration and accurate, stable positioning and ablation of the arrhythmogenic substrate.

This report provides a detailed description of a new remote navigation system based on magnetic driven forces, which has been recently introduced as a new robotic tool for human cardiac electrophysiology procedures.

New remote navigation systems have been developed to improve current limitations of conventional manually guided catheter ablation in complex cardiac ...

Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting millions of individuals worldwide 1-3. The rapid, irregular, and disordered electrical activity in the atria gives rise to palpitations, fatigue, dyspnea, chest pain and dizziness with or without syncope 4, 5. Patients with AF have a five-fold higher risk of stroke 6.
Oral anticoagulation (OAC) with warfarin is commonly used for stroke prevention in patients with AF and has been shown to reduce the risk of stroke by 64% 7. Warfarin therapy has several major disadvantages, however, including bleeding, non-tolerance, interactions with other medications and foods, non-compliance and a narrow therapeutic range 8-11. These issues, together with poor appreciation of the risk-benefit ratio, unawareness of guidelines, or absence of an OAC monitoring outpatient clinic may explain why only 30-60% of patients with AF are prescribed this drug 8.
The problems associated with warfarin, combined with the limited efficacy and/or serious side effects associated with other medications used for AF 12,13, highlight the need for effective non-pharmacological approaches to treatment. One such approach is catheter ablation (CA), a procedure in which a radiofrequency electrical current is applied to regions of the heart to create small ablation lesions that electrically isolate potential AF triggers 4. CA is a well-established treatment for AF symptoms 14, 15, that may also decrease the risk of stroke. Recent data showed a significant decrease in the relative risk of stroke and transient ischemic attack events among patients who underwent ablation compared with those undergoing antiarrhythmic drug therapy 16.
Since the left atrial appendage (LAA) is the source of thrombi in more than 90% of patients with non-valvular atrial fibrillation 17, another approach to stroke prevention is to physically block clots from exiting the LAA. One method for occluding the LAA is via percutaneous placement of the WATCHMAN LAA closure device. The WATCHMAN device resembles a small parachute. It consists of a nitinol frame covered by fabric polyethyl terephthalate that prevents emboli, but not blood, from exiting during the healing process. Fixation anchors around the perimeter secure the device in the LAA (Figure 1). To date, the WATCHMAN is the only implanted percutaneous device for which a randomized clinical trial has been reported. In this study, implantation of the WATCHMAN was found to be at least as effective as warfarin in preventing stroke (all-causes) and death (all-causes) 18. This device received the Conformit&eacute; Europ&eacute;enne (CE) mark for use in the European Union for warfarin eligible patients and in those who have a contraindication to anticoagulation therapy 19.
Given the proven effectiveness of CA to alleviate AF symptoms and the promising data with regard to reduction of thromboembolic events with both CA and WATCHMAN implantation, combining the two procedures is hoped to further reduce the incidence of stroke in high-risk patients while simultaneously relieving symptoms. The combined procedure may eventually enable patients to undergo implantation of the WATCHMAN device without subsequent warfarin treatment, since the CA procedure itself reduces thromboembolic events. This would present an avenue of treatment previously unavailable to patients ineligible for warfarin treatment because of recurrent bleeding 20 or other warfarin-associated problems.
The combined procedure is performed under general anesthesia with biplane fluoroscopy and TEE guidance. Catheter ablation is followed by implantation of the WATCHMAN LAA closure device. Data from a non-randomized trial with 10 patients demonstrates that this procedure can be safely performed in patients with a CHADS2 score of greater than 1 21. Further studies to examine the effectiveness of the combined procedure in reducing symptoms from AF and associated stroke are therefore warranted.

Catheter ablation is combined with placement of the WATCHMAN Left Atrial Appendage Closure Device to prevent ischemic stroke in a patient with non-valvular atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting millions of individuals worldwide 1-3. The rapid, irregular, and ...

Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation

Cryoballoon ablation (CBA) is an established therapy for atrial fibrillation (AF). Pulmonary vein (PV) occlusion is essential for achieving antral contact and PV isolation and is typically assessed by contrast injection. We present a novel method of direct pressure monitoring for assessment of PV occlusion.
Transcatheter pressure is monitored during balloon advancement to the PV antrum. Pressure is recorded via a single pressure transducer connected to the inner lumen of the cryoballoon. Pressure curve characteristics are used to assess occlusion in conjunction with fluoroscopic or intracardiac echocardiography (ICE) guidance. PV occlusion is confirmed when loss of typical left atrial (LA) pressure waveform is observed with recordings of PA pressure characteristics (no A wave and rapid V wave upstroke). Complete pulmonary vein occlusion as assessed with this technique has been confirmed with concurrent contrast utilization during the initial testing of the technique and has been shown to be highly accurate and readily reproducible.
We evaluated the efficacy of this novel technique in 35 patients. A total of 128 veins were assessed for occlusion with the cryoballoon utilizing the pressure monitoring technique; occlusive pressure was demonstrated in 113 veins with resultant successful pulmonary vein isolation in 111 veins (98.2%). Occlusion was confirmed with subsequent contrast injection during the initial ten procedures, after which contrast utilization was rapidly reduced or eliminated given the highly accurate identification of occlusive pressure waveform with limited initial training.
Verification of PV occlusive pressure during CBA is a novel approach to assessing effective PV occlusion and it accurately predicts electrical isolation. Utilization of this method results in significant decrease in fluoroscopy time and volume of contrast.

Effective pulmonary vein isolation utilizing a cryoballoon depends on complete pulmonary vein occlusion. The point of occlusion can be effectively predicted by direct analysis of pulmonary vein pressure waveform analysis during balloon inflation using a simple and reproducible technique.

Cryoballoon  ablation (CBA) is an established therapy for atrial fibrillation (AF).  Pulmonary vein (PV) occlusion is essential for achieving antral ...

Robotic Ablation of Atrial Fibrillation

Background: Pulmonary vein isolation (PVI) is an established treatment for atrial fibrillation (AF). During PVI an electrical conduction block between pulmonary vein (PV) and left atrium (LA) is created. This conduction block prevents AF, which is triggered by irregular electric activity originating from the PV. However, transmural atrial lesions are required which can be challenging. Re-conduction and AF recurrence occur in 20 - 40% of the cases. Robotic catheter systems aim to improve catheter steerability. Here, a procedure with a new remote catheter system (RCS), is presented. Objective of this article is to show feasibility of robotic AF ablation with a novel system. Materials and Methods: After interatrial trans-septal puncture is performed using a long sheath and needle under fluoroscopic guidance. The needle is removed and a guide wire is placed in the left superior PV. Then an ablation catheter is positioned in the LA, using the sheath and wire as guide to the LA. LA angiography is performed over the sheath. A circular mapping catheter is positioned via the long sheath into the LA and a three-dimensional (3-D) anatomical reconstruction of the LA is performed. The handle of the ablation catheter is positioned in the robotic arm of the Amigo system and the ablation procedure begins. During the ablation procedure, the operator manipulates the ablation catheter via the robotic arm with the use of a remote control. The ablation is performed by creating point-by-point lesions around the left and right PV ostia. Contact force is measured at the catheter tip to provide feedback of catheter-tissue contact. Conduction block is confirmed by recording the PV potentials on the circular mapping catheter and by pacing maneuvers. The operator stays out of the radiationfield during ablation. Conclusion: The novel catheter system allows ablation with high stability on low operator fluoroscopy exposure.

Pulmonary vein isolation (PVI) with an ablation catheter is a curative treatment for atrial fibrillation (AF). Robotic catheter systems aim to improve catheter steerability. Here, a procedure with a new robotic catheter system is presented. The goal of the procedure is electrical block between pulmonary vein and left atrium.

Background: Pulmonary vein isolation (PVI) is an established treatment for atrial fibrillation (AF). During PVI an electrical conduction block between ...

Two Techniques to Create Hypoparathyroid Mice: Parathyroidectomy Using GFP Glands and Diphtheria-Toxin-Mediated Parathyroid Ablation

Hypoparathyroidism (HP) is a disorder characterized by low levels of PTH which lead to hypocalcemia, hyperphosphatemia, and low bone turnover. The most common cause of the disease is accidental removal of the parathyroid glands during thyroid surgery. Novel therapies for HP are needed, but testing them requires reliable animal models of acquired HP. 
Here, we demonstrate the generation of two mouse models of acquired HP. In the GFP-PTX model, mice with green fluorescent protein (GFP) expressed specifically in the parathyroids (PTHcre-mTmG) were created by crossing PTHcre+ mice with Rosa-mTmGfl/fl mice. Green fluorescing parathyroid glands are easily identified under a fluorescence dissecting microscope and parathyroidectomy is performed in less than 20 min. After fluorescence-guided surgery, mice are profoundly hypocalcemic. Contrary to the traditional thyro-parathyroidectomy, this precise surgical approach leaves thyroid glands and thyroid function intact. The second model, which does not require surgery, is based on a diphtheria-toxin approach. PTHcre-iDTR mice, which express the diphtheria toxin (DT) receptor specifically in the parathyroids, were generated by crossing the inducible DTR mouse with the PTHcre mouse. Parathyroid cells are thus rendered sensitive to diphtheria toxin (DT) and can be selectively destroyed by systemically injecting mice with DT. The resulting hypocalcemic phenotype is stable.

Mice with acquired hypoparathyroidism would be useful for studying novel drug therapies for hypoparathyroidism. Two procedures to create such mice are demonstrated. The GFP-PTX mouse is generated by surgical parathyroidectomy guided by green fluorescing parathyroid glands. A second, non-surgical approach is based on parathyroid-specific expression of the diphtheria toxin receptor.

Hypoparathyroidism (HP) is a disorder characterized by low levels of PTH which lead to hypocalcemia, hyperphosphatemia, and low bone turnover. The most ...

Imaging Metals in Brain Tissue by Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS)

Metals are found ubiquitously throughout an organism, with their biological role dictated by both their chemical reactivity and abundance within a specific anatomical region. Within the brain, metals have a highly compartmentalized distribution, depending on the primary function they play within the central nervous system. Imaging the spatial distribution of metals has provided unique insight into the biochemical architecture of the brain, allowing direct correlation between neuroanatomical regions and their known function with regard to metal-dependent processes. In addition, several age-related neurological disorders feature disrupted metal homeostasis, which is often confined to small regions of the brain that are otherwise difficult to analyze. Here, we describe a comprehensive method for quantitatively imaging metals in the mouse brain, using laser ablation - inductively coupled plasma - mass spectrometry (LA-ICP-MS) and specially designed image processing software. Focusing on iron, copper and zinc, which are three of the most abundant and disease-relevant metals within the brain, we describe the essential steps in sample preparation, analysis, quantitative measurements and image processing to produce maps of metal distribution within the low micrometer resolution range. This technique, applicable to any cut tissue section, is capable of demonstrating the highly variable distribution of metals within an organ or system, and can be used to identify changes in metal homeostasis and absolute levels within fine anatomical structures.

Imaging Metals in Brain Tissue by Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry LA-ICP-MS

Quantitatively mapping metals in tissue by laser ablation - inductively coupled plasma - mass spectrometry (LA-ICP-MS) is a sensitive analytical technique that can provide new insight into how metals participate in normal function and disease processes. Here, we describe a protocol for quantitatively imaging metals in thin sections of mouse neurological tissue.

Metals are found ubiquitously throughout an organism, with their biological role dictated by both their chemical reactivity and abundance within a ...

Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction

Ventricular tachycardia (VT) in patients with ischemic cardiomyopathy mainly results from endocardial scars after myocardial infarction; those scars represent zones of slow conduction that allow the occurrence and maintenance of reentrant circuits. Catheter ablation enables substrate modification of those low voltage areas and thus can help to alter the scar tissue in such a way that arrhythmias cannot appear anymore. Hospitalizations of concerned patients decrease, quality of life and outcome rise. Consequently, VT ablation represents a growing field in electrophysiology, especially for patients with endocardial scars in ischemic heart disease after myocardial infarction. However, ablation of ventricular tachycardia remains one of the most challenging procedures in the electrophysiology lab. Precise scar definition and localization of abnormal potentials are critical for ablation success. The following manuscript describes the use of a multipolar mapping catheter and 3-dimensional (3D) mapping system to create a high density electro-anatomical map of the left ventricle including a precise scar representation as well as mapping of fractionated and late potentials in order to allow a highly accurate substrate modification.

With the following protocol, we provide an approach to Ventricular Tachycardia (VT) ablation using high density mapping with a multipolar catheter and 3D mapping system enhancing the success of the procedure.

Ventricular tachycardia (VT) in patients with ischemic cardiomyopathy mainly results from endocardial scars after myocardial infarction; those scars ...

Evaluation of Patients' Posture and Gait Profile After Lumbar Fusion Surgery by Video Rasterstereography and Treadmill Gait Analysis

This protocol provides guidance on how to perform high resolution video rasterstereography and treadmill gait analysis on patients after lumbar fusion surgery to obtain results about altered variables of gait and posture. These observed changes can then be correlated with the patient-reported outcome measure of pain relief. The rasterstereographic device projects lines of parallel light onto the surface of the tested subject&#39;s back. The deformation of these lines is recognized by the device. From these data, a special software then generates a 3-D profile based on the principle of triangulation. With an inaccuracy of only 0.2 mm it can measure changes in posture at very high precision. Gait and stance parameters are recorded using a treadmill equipped with an electric sensor mat that contains 10,200 miniature force sensors in the registering zone under the belt. Initial walking speed on the treadmill is 0.5 km/h. Speed is then gradually increased by increments of 0.1 km/h until each subject reaches his or her individual maximum well tolerable walking speed. At this speed, parameters are recorded during a 20 s measurement interval. Subjects are tested barefoot and without holding a handrail. Among various other parameters, stride width, step length, stance phase and foot rotation are measured. Both methods used reportedly have a high intra- and inter-observer reliability. The advantage of these highly accurate techniques is that they offer an objective and very detailed perspective on changes in the patient&#39;s posture and gait. Due to the amount of data generated, these techniques are, however, not so much suitable for everyday routine use, but rather interesting to scientifically evaluate long term alterations in posture and gait in patients like for example after lumbar fusion surgery.

Here, we present a protocol to analyze the posture and the gait of patients after lumbar fusion surgery by means of high-resolution video rasterstereography and a treadmill equipped with an integrated sensor mat. Allowing critical functional postoperative evaluation on a less subjective level may enhance accuracy and reliability of indication for surgery.

This protocol provides guidance on how to perform high resolution video rasterstereography and treadmill gait analysis on patients after lumbar fusion ...

Focal Laser Ablation of Prostate Cancer: An Office Procedure

In this article, we describe and illustrate an outpatient procedure for focal laser ablation (FLA) of prostate cancer (PCa). The procedure is conceptually similar to a fusion biopsy and is performed under local anesthesia in a clinic setting; treatment time is usually less than one hour. Laser insertion is guided by ultrasound; lesion targeting is via magnetic resonance imaging-ultrasound (MRI/US) fusion, as in targeted prostate biopsy. Real-time ablation monitoring is achieved utilizing a thermal probe adjacent to the laser fiber. The video demonstrates procedure planning, patient preparation, various steps during the procedure, and treatment monitoring. Safety, feasibility, and efficacy of this approach have been established during a previous trial. Outpatient FLA under local anesthesia is an option for management of intermediate risk prostate cancer.

This article presents and describes an outpatient treatment for prostate cancer using focal laser ablation. Laser catheter placement is guided by MRI-ultrasound fusion imaging in a fashion similar to prostate needle biopsy. Treatment is monitored in real-time with a thermal probe, placed adjacent to the laser fiber.

In this article, we describe and illustrate an outpatient procedure for focal laser ablation (FLA) of prostate cancer (PCa). The procedure is conceptually ...