Applications of Holmium Laser in Urology.
Abstracts.

"Application of the Ho-YAG laser in the treatment of ureteric and ureteropelvic strictures".
A. Chepurov, A. Nemenova, S. Zenkov, Ts.Dondukov. Clinic of Urology, Russian State Medical University, Moscow.
Proceedings of VIII International meeting, Soc. for Minimally Invasive Therapy, Cernobbio, Italy, 18-20 Sept. 1996. "Minimally Invasive Therapy", v.5, Suppl.1, 1996, p. 56.

The experience of treatment of patients with ureteric and ureteropelvic strictures using Holmium Laser is presented.
The Laser device on the basis of Holmium Laser functioning in pulsed fashion at a wavelength of 2.09 mm, with energy 0.2 - 1.5 J and frequency 1 - 15 Hz was used during treatment.
We have performed 7 endoscopic correction of strictures in 6 patients (female range 22 - 47). Incisive and ablative effects of the Holmium Laser were used. In 5 cases strictures were incised. Extention of strictures were from 0.5 - 1.2 cm. Ablative effect was reached in 1 case in patient with extension of stricture 0.3 cm. Double-j ureteral stent was placed after each operation. The range of energy during the operation was 0.5 J and frequency was 5 - 10 Hz. We maintained this optional laser parameters after experimental application of Ho:YAG laser energy on ureter tissue in vivo during rephroureterectomy.
The results were satisfactory in 5 cases. In 1 case incision of the stricture was performed twice. But we failed to get normal condition of ureter. This resulted nephrectomy due to acute pyelonephritis and highly decreasing function of the kidney. Patients with nephrostomy had a better technical conditions of conducting operations.
We consider that the HO:YAG laser can be effectively used either as a primary treatment or in a combination with other endourological methods in patients with the strictures of upper urinary tract.

"Application of the Ho-YAG laser in the treatment of ureteral and bladder neck strictures in males".
A. Chepurov, E. Mazo, L. Plakatin, E.Tarasova. Clinic of Urology, Russian State Medical University, Moscow.
Proceedings of VIII International meeting, Soc. for Minimally Invasive Therapy, Cernobbio, Italy, 18-20 Sept. 1996. "Minimally Invasive Therapy", v.5, Suppl.1, 1996, p. 71

The experience of treatment of patients with uretral and bladder neck strictyres using Holmium Laser is presented.
Laser device on the basis of Holmium Laser functioning in pulsed fashion at a wavelength of 2.09 mm, with energy 0.2 - 1.5 J and frequency 1 - 15 Hz was used during treatment.
We have performed 33 endoscopic corrections in 30 patients (24 - 73 years old). Stricture extension were 0.5 - 1.5 cm. Incisive and ablative effects of the Holmium Laser were used.
It was used laser energy 0.5 J and frequency 5 - 10 Hz. Optimal laser parameters were maintained during the experiment in vivo under the performance of transvesical prostatectomy.
Stable improvement of urodinamic parameters was observed 10 - 12 months postoperatively in 93.3 % of patients.
We believe, that Holmium Laser can be used as either separate method, or in combination with other endourological methods in the treatment of patients with uretral and bladder neck strictures.

"Methods of fragmentation of ureteral stones using the Ho-YAG-laser".
A. Chepurov, A. Nemenova, E. Mazo. Clinic of Urology, Russian State Medical University, Moscow. Proceedings of XII Congress of European association of Urology, Paris, 1-4 Sept. 1996. "European Urology" v.30, Suppl.2, Aug 1996, p. 125.

Introduction: the special properties of the 2 mm wavelength allow to use the Ho:YAG laser for the fragmentation of ureteral stones.
Materials and methods: Ho:YAG laser in a pulsing mode used for the treatment of 16 patients with ureteral stones. Methodics of contact and remote laser influence were used onto ureteral stones under the constant liquid irrigation of ureter and without irrigation in case of the capture of a stone by Dormia loop. Then the stones were fixed to ureteral mucosa, the fragmentation process started from its free part, moving gradually towards its fixing part. Each method of fragmentation has its indications.
Results: 15 patients became free of single stones sized up to 1.2 cm; one became free of the stone road of 1.5 cm long which appeared after the kidney stone fragmentation; 3 patients had their single stones crushed into small fragments one of which was eliminated with a Dormia loop thereafter; another patient had one of the stone fragments treated using the ultra-sound in addition to a laser. Majority of patients underwent fragmentation resulting in formation of fragments of 1 mm and less, which left the ureter spontaneously without any complications.
Conclusion: 2.09 mm wavelength Ho:YAG pulse laser can be successfully used for ureteral stones fragmentation. The method is simple and can be mastered in short time. This laser unit is ready for operation in less than 5 min. The remote method of fragmentation is expedient for "soft" stones. However, at the majority of patients, contact method is the most effective at "hard" stones. In accordance with the reduction of sizes of a stone we recommend to continue fragmentation without submission of a liquid for prevention of stone migration. The capture of a stone by a Dornia loop promotes its successful fragmentation, and if necessary extraction. Fragmentation of the free part of the fixed stone prevents the damage of ureteral wall.

"Применение гольмиевого лазера в оперативной урологии".
Е. Б. Мазо, А. К. Чепуров. "Вестник РГМУ", МЗ РФ, М., N 1/2, 1996, стр. 40-43

Ho:YAG laser operates in impulse regimen with transmission of radiation along the fiber 400 - 600 nm in diameter (mean power 12 W, impulse rate 1 - 15 Hz, energy of one impulse 0.7 - 1.5 J, its duration 300 ms).These parameters provide the effect of intensive biotissue evaporation, dissection of contact tissue, disintegration of concrements, hemostasis. Ho:YAG laser was employed for treatment of 8 patients with urethral polyp, 4 with strictures of the bladder neck and urethra, 5 with prostatic adenoma, 12 with bladder tumor, 10 with ureterolith, 5 with urolith, 4 with penile lesions, 2 with ureteral stricture, 4 with ureterocele. Ho:YAG laser was used primarily for endoscopic interventions. Its use for open surgery is also promising. Further practical experience with Ho:YAG laser will provide additional information on its indications in urological diceases.

"Гольмиевый лазер в лечении больных раком мочевого пузыря".
Е.Б.Мазо, А. К. Чепуров. "Урология и нефрология", Медицина, М., N4, 1996, стр. 34-35.

37 patients with cancer of the urinary bladder have undergone surgery and radiation with Ho-YAG laser. In 11 patients transurethral resection was followed by bladder wall ablation by impulse laser radiation (0.5 - 1.0 W, 3 - 10 Hz). Pilot results were promising: good coagulation effects, absence of secondary hemorrhage and infectious-inflammatory complications due to shorter postoperative drainage of the bladder and safety of ablation effect in exposure of the tumor base.

The tissue effects of a holmium:YAG (Ho:YAG) laser operating at a wavelength of 2.1 µ with a maximum power of 15 watts (W) and 10 different energy-pulse settings was systematically evaluated on kidney, bladder, prostate, ureteral, and vasal tissue in the dog. In addition, various urologic surgical procedures (partial nephrectomy, transurethral laser incision of the prostate, and laser-assisted vasostomy) were performed in the dog, and a laparoscopic pelvic lymph node dissection was carried out in a pig. Although the Ho:YAG laser has a strong affinity for water, precise tissue ablation was achieved in both the contact and non-contact mode when used endoscopically in a fluid medium to ablate prostatic and vesical tissue. Using the usual parameters for tissue destruction (blanching without charring), the depth of thermal injury in the bladder and ureter was kept superficial. In performing partial nephrectomies, a two-fold reduction in the zone of coagulative necrosis was demonstrated compared to the use of the continuous wave Neodymium:YAG laser (Nd:YAG). When used through the laparoscope, the Ho:YAG laser provided precise cutting and, combined with electrocautery, allowed the dissection to proceed quickly and smoothly. Hemostatic control was adequate in all surgical procedures. Although the results of these investigations are preliminary, our initial experience with the Ho:YAG laser has been favorable and warrants further investigations.

Fifty-one cases of VersaPulse Holmium laser treatment of various urologic conditions are presented. The laser was easy to use and was equally effective through fluid and carbon dioxide media for soft tissue ablation, lithotripsy and laparoscopic surgery. The laser demonstrated precision haemostatic cutting and was particularly suited to superficial ablation of lesions in the bladder and urethra and for the fragmentation of ureteric calculi. We feel this laser warrants further investigation as an urological laser and may have applications in other fields of endoscopic surgery.

"Use of the holmium:YAG (Ho:YAG) laser for treatment of superficial bladder carcinoma"
Johnson D.E. "Lasers in Surgery and Medicine" 1994; 14: 213-218

This is the first North American report describing the use of the Holmium:YAG (Ho:YAG) laser to treat patients with superficial bladder carcinoma. Fifteen patients, with a total of 52 recurrent superficial bladder tumors, underwent endoscopic laser photoablation of their lesions.We conclude that using the Ho:YAG for endoscopic treatment of patients with superficial bladder tumors is both feasible and clinically useful and that the lack of perceived pain or discomfort during lasing, as well as the lack of need for an in-dwelling urethral catheter, makes it advantageous for selected patients over conventional electroresection techniques.

"Use of the holmium laser in the upper urinary tract".
D. Bagley, M.Erhard. "Techniques in Urology", v. 1, N 1, 1995, p. 25-30.

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"Preliminary experience with the holmium:YAG laser lithotripcy".
J.D. Denstedt, H. A. Razvi, J. L. Sales, P. M. Eberwein. "Journal of endourology", v. 9, N 3, 1995, p. 255-257.

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Thirty-eight procedures utilizing transurethral ureterolithotripsy or percutaneous nephroureteral lithotripsy were evaluated. On the basis of the results from this study, the Holmium wavelength is effective for lithotripsy in addition to its previously reported usefulness for soft tissue applications, and thus, is a cost-effective and highly useful clinical device.

Until recently, treatment options for patients with cystine calculi were not favorable. Using holmium:yttrium-aluminum-garnet (YAG) lasers to fragment cystine calculi, however, may provide a minimally invasive and cost-effective alternative to current treatments. This article describes cystine calculi and the diagnostic methods and current medical and surgical interventions used to treat patients and discusses the differences between flash lamp pulsed dye lasers and holmium:YAG lasers. Preoperative, intraoperative, and postoperative considerations for laser ureterolithotripsy of cystine calculi also are discussed.

"The evolution of the use of the holmium laser for the treatment of Benign Prostatic Hyperplasia".
P.J.Gilling, C.B.Cass, M.D.Cresswell, K.M.Kennett, M.Mackey, M.R.Fraundorfer, J.N.Kabalin. SPIE Proceedings 1997; 2970: 448-451

The Holmium laser is becoming an important tool in the urologists armamentarium. In this manuscript, the evolution of laser resection of the prostate using theholmium wavelength is described. This technique represents a significant advance in the surgical management of benign prostatic hyperplasia and allows even very large prostates to be safely and efficiently managed transurethrally.

Holmium:YAG laser cystolithotripsy of large bladder calculi is effective, technically facile, and safe. The 550-µm side-firing fiber may be better suited for large bladder calculi compared with the 365-µm end-firing fiber. Holmium:YAG cystolithotripsy may obviate open cystolithotomy in selected patients.

"Holmium Laser Resection of the Prostate"
A.L.Duc, P.J.Gilling www.wave.co.nz/pages/urology/eurorev.html 1998

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Applications of Holmium Laser in Gynaecology.
Abstracts.

"Joint endometrial ablation".
A. Ischenko, V. Zuev, T. Djibladze, A.Bachalova, L. Djavachia. Proceedings of the 5-th Congress of the European Soc. for Gynaecological Endoscopy, Bratislava, 18-21 Sept. 1996, Abstracts, p. 26

Endometrial ablation by Ho-YAG laser and resectoscopy was performed in 32 patients age of 38 - 52. Incision criteria was sever menstrual blood loss, refractive to conservative treatment, no malignancy.
Aim of the study: To compare the efficiency of hysteroscopic resection and laser endometrial ablation as separate methods and its combination.
Patients and methods: 21 patients undergone general electrosurgery, 12 - laser ablation, and 32 women undergone combinative endometrial ablation. The main purpose of simultaneous use of laser and resectoscopy was the total destruction of endometrium in corpus utery and in cornal areas. All patients received preoperative medical reduction of endometrium by Danazol.
Results: In patients with endometrial ablation made by resectoscope we observed "tubal syndrome" in 52 %, in patients with combinative methods - in 10 %.
Conclusion: This study demonstrates the advantage of combination of electrosurgery and Ho-YAG uterine surgery in patients with heavy menstrual loss to general resectocsopy.

"Use of Ho-YAG laser in the treatment of tubal and peritoneal infertility".
V. Zuev, A. Ischenko, T. Djibladze, D. Krasnikov, M.Botvin, A. Lypman. Proceedings of the 5-th Congress of the European Soc. for Gynaecological Endoscopy, Bratislava, 18-21 Sept. 1996, Abstracts, p. 106.

We used Ho-YAG laser for destruction of adhesions, endometriosis tubal reconstruction in patients with infertility by laparoscopy.
This study showed basical difference in using Nd-YAG and Ho-YAG laser in laparoscopic surgery. Ho-YAG laser showed to be safe and highly effective.

"Современные аспекты лазерной внутриматочной хирургии"
В.М.Зуев, А.И.Ищенко, Н.М.Побединский, Т.А.Джибладзе, А.Д.Липман, Т.И.Гогоберидзе. Междунар. конгресс "Лазер и здоровье-99", г. Москва, 8-10 декабря 1999 г. Тез. докл. М., 1999, с.145-146

386 patients age of 23 - 52 years with endometrium polips, hyperplasia, myoma and adenomyosis, adhesions and septi.
The following aspects for facilitating surgery were noted:
1) Choice of laser output (Nd-YAG, Ho-YAG, etc.)
2) Hormone preparation
3) Non-surgical preparation
4) Choice of optical system
5) Laser technique - coagulation, vaporization, section, etc.
6) Endocrine control.
This amount of features develop the minimum of complications and posttreatment success.

"Преимущества трансвагинальной лазерной каутеризации яичников как малотравматичного оперативного метода коррекции ановуляции у женщин с синдромом поликистозных яичников".
"Лазерная медицина", 2000, т.4, вып.4, с.61-62

Independent investigations have already demonstrated the efficiency of laparoscopic laser cauterization of ovaries. Special interest was therefore shown in the development of a technique for less invasive transvaginal access during surgery-induced ovulation. The aim of our research was to reveal the advantages of transvaginal laser cauterization of ovaries as atraumatic method for correcting annovulation in women with a set of symptoms of polycystic ovaries. A group of women of the genesial age who suffered from polycystic ovaries and infertility resistant to medicamental treatment underwent the transvaginal laser cauterization of ovaries. The intervention had neither intra- nor postoperative complications/ Two women became pregnant and one of them gave birth to a healthy boy. Thus, the transvaginal laser cauterization of ovaries under ultrasonic monitoring combines the advantagies of classical laparoscopic laser cauterization of ovaries, and it has minimal traumatism of the transvaginal tract, which is traditionally used for extracorporeal fertilization.

Applications of Holmium Laser in ENT Surgery.
Abstracts.

"О некоторых возможностях применения в ЛОР-клинике некоторых видов твердотельных лазеров (l=1.54 и 2.09 мкм)".
В. Г. Зенгер, А. Н. Наседкин, В. Н. Селин. Международная конференция "Новые достижения лазерной медицины", С-Пб, 1993, с. 81-82.

Experimental studies demonstrated some advantages of new types of lasers compared to the old ones. The study was initiated in ENT practice, special success being achieved in destruction of cicatrical tissue.

"Гольмиевый лазер для целей хирургии и эндоскопии"
Горбатова Н.Е., Жадько В.М., Елисеенко В.И., А. Н. Наседкин, Никольский М.Ю. Междунар. конф. "Новые достижения лазерной медицины", С-Пб, 1993, с.366-367.

The unique combination of such properties of Ho:YAG laser as ablation, dissection, hemostasis and the possibility of transmission of its energy using fiberoptic delivery systems make the application of Ho:YAG laser very effective in surgery, endoscopy and other fields of medicine.

"Применение лазерного излучения 2,09 мкм в хирургии заболеваний и повреждений ЛОР-органов"
Зенгер В.Г., Наседкин А.Н., Авадалах А., Добчинов С. В кн. "Клиническое и экспериментальное применение новых лазерных технологий". Мат. междунар. конф., Москва - Казань, с.52-53, 1995.

After the successful experimental research the surgical laser installation CTH-10 on the basis of YAG-holmium laser was created. It was admitted to the medical practice and is used with great success in the E.N.T.-clinic of MRRCI.

"Study of cartilage reshaping with holmium laser".
E. Sobol, V.Bagratashvili, A. Sviridov, A. Omel'chenko, M. Kitai, N. Jones, V.Zenger, A. Nasedkin, M. Isaev, V. Karlov, A. Sheshter. Proceedings of SPIE, v. 2623, Jan., 1996.

We examine thermal effect of a 2.1 mm Holmium laser on the internal stress and shape of cartilage. For 2.1 microns radiation, the absorption depth is more by an order of magnitude than that, for 10 mm radiation. We have studied the influence of laser intensity, pulse duration, pulse repetition rate, and of cartilage thickness on its shaping conditions. Spatial and temporal locality of Ho laser radiation as well as the bulk character of the heating allow to produce the stress relaxation without overheating of the surface irradiated and to prevent undesirable effects of tissue carbonization and destruction.

"Экспериментальное и клиническое обоснование применения хирургического гольмиевого лазера в оториноларингологии"
А.Н.Наседкин, С.В.Грачев, В.Г.Зенгер, А.В.Шестаков, М.П.Исаев, А.Г.Талалаев "Лазерная медицина", т.1, вып.2, 1997, с.18-22.

A comparative analysis has first been experimentally conducted on animals as to the effect of laser radiation with different wavelengths (1.06, 1.54, 2.09, 2.94 and 10.6 mm) on biological tissues. The best results by all parameters and impact on biological tissue have achieved with holmium laser (2.09 mm) that served as the basis for the surgical set-up CTH-10. The results of clinical application of the new set-up that was permitted for wide clinical application by the Ministry of Health of the Russian Federation and ROSTEST demonstrated that it was possible to perform unique surgical operations with the help of the above mentioned device.

"Метод лакунотомии небных миндалин при помощи излучения ИАГ-гольмиевого лазера"
И.В.Лесков, А.Н.Наседкин, И.С.Маневич, А.А.Петлев. Междунар. конгресс "Лазер и здоровье-99", г. Москва, 8-10 декабря 1999 г. Тез. докл. М., 1999, с.77

Laser ablation of the crypts of palatine tonsils is a useful alternative to tonsillectomy. Ablation of surface pockets (crypts) of the palatine tonsils utilizing the holmium:YAG laser was effective in 23 of 25 patients with chronic cryptic tonsillitis (age of 10 to 38 years; 13 males and 12 females) treated in the past 6 to 8 months. Ablation of the crypts of palatine tonsils was performed in stages under local anesthesia in outpatient conditions by the technique developed at the Department of Clinical and Experimental Research in Otolaryngology of I.M.Sechenov Moscow Medical Academy. In the postoperative period we saw no intoxication or post-operative pain like in CO2 or Nd:YAG laser-assisted ablation of the crypts of palatine tonsils.

"Новый лазерный метод лечения вазомоторного ринита"
Л.Ю.Мусатенко, В.Г.Зенгер, А.Н.Наседкин, В.И.Самбулов. Междунар. конгресс "Лазер и здоровье-99", г. Москва, 8-10 декабря 1999 г. Тез. докл. М., 1999, с.97

In otorhinolaryngology clinic Moscow Region Scientific-Research Clinical Institute the new method of treating patients with allergic and vasomotor rhinopathies has been worked out. It is based on using the Holmium:YAG (Ho:YAG) laser radiation with the wavelength of 2.09 mm. The principle of the method is based on extremely friendly destruction of inferior turbinates with the help of the Ho:YAG laser. It may be transmitted by the classic fiber optics. At present at our disposal there are the results of practicing this method on 273 patients ranging from 6 to 69 years old. The grounds for making laser operations were: ineffective conservative therapy being practiced for 2 years and unsatisfactory results of traditional surgery. The results of rigid and flexible endoscopy made it possible to determine the volume of laser destruction. The operation lasted for 15 minutes with the time of local anesthesia being included. In rare cases when children were operated general anesthesia was used. There were no intra- or post-operation complications. 255 (93.4 %) patients got the recovery of basic functions of the nose. The scientific research proved that the therapy effect didn't depend on the duration of the disease or its symptoms. The evidence of the advantage of laser operations is the fact that a year later after the operation 247 (90.5 %) patients had stable positive results. The research and practical work proves that the destruction of inferior turbinates by the Ho:YAG laser radiation is an extremely effective and progressive method of treating patients with allergic and vasomotor rhinopathies.

"Амбулаторное хирургическое лечение храпа с помощью лазера"
А.Н.Наседкин, В.Г.Зенгер. Междунар. конгресс "Лазер и здоровье-99", г. Москва, 8-10 декабря 1999 г. Тез. докл. М., 1999, с.101

Authors have successfully developed and applied two laser-assisted (l - 1.54, 2.09, 1.06, 0.81 mm) techniques of snoring and sleep apnea treatment. 322 patients have been operated on. Efficacy after one-stage surgery has achieved 73 %, after the second procedure - 95 %. There have been no complications noted.

"Лазерная лакунотомия небных миндалин"
И.В.Лесков, И.С.Маневич, А.А.Петлев. "Лазерная медицина", 2000, т.4, вып.4, с.58-59

This article considers the advantages of a new laser lacunotomy technique for treating palatine tonsils during chronic tonsillitis. This technique is realized with the aid of a Ho:YAG laser by using a principally new technique, which makes it possible to perform lacunotomy of palatine tonsils when a minimal wound surface with minimal healing terms of operative wounds appears. Apart from that, this technique has similar efficiency to that of well-known techniques. This article also presents information on the follow-up study.

Applications of Holmium Laser in Orthopedy.
Abstracts.

"Study of cartilage reshaping with holmium laser".
E. Sobol, V.Bagratashvili, A. Sviridov, A. Omel'chenko, M. Kitai, N. Jones, V.Zenger, A. Nasedkin, M. Isaev, V. Karlov, A. Sheshter. Proceedings of SPIE, v. 2623, Jan., 1996.

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"Применение гольмиевого лазера при артроскопии коленного сустава"
Лазко Ф.Л., Макаров Д.Г., Перекокин Ю.Н. Материалы Первого конгресса РАО. Москва, 25-26 ноября 1996 г.

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"Использование гольмиевого лазера при лечении хондральных переломов коленного сустава"
Лазко Ф.Л., Нисс-Бассим, А.Ю.Михайлов. Материалы Второго конгресса РАО. Москва, 1997 г

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"Анализ применения гольмиевого лазера при артроскопическом лечении хрящевой патологии коленного сустава".
Лазко Ф.Л., Нисс-Бассим, Бадамшин Э.Р. Материалы Третьего конгресса РАО. Москва, 1999 г

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"Артроскопическое лечение посттравматического гонартроза с использованием гольмиевого лазера".
Нисс Бассим Абдель-Фаттах. Дис. канд. мед. наук (РУДН) - Защищена 2001.05.10. УДК 617.3. 117 с.: 13 таб., 32 ил. - Библиогр.: 197 назв.

Впервые изучено влияние гольмиевого лазера на репаративные процессы хрящевой ткани при посттравматическом артрозе коленного сустава после артроскопических операций. Показано, что лазерная энергия стимулирует репаративные процессы хондроцитов, что является основой регенерации хряща. Впервые проведена оценка синовиальной среды коленного сустава после лечения гольмиевым лазерным лучом. Разработаны основные принципы использования гольмиевого лазера для лечения посттравматического гонартроза с помощью артроскопического метода, определены показания и противопоказания при использовании гольмиевого лазера у больных гонартрозом. Разработана методика реабилитации больных гонартрозом после артроскопической хондропластики с использованием гольмиевого лазера.

A Holmium-yttrium scandium gallium garnet laser is a pulsed midinfrared crystalline laser (wavelength, 2.1 µm ), which is easily transmissible through flexible quartz fibers. With use of a 300 µm fiber delivery system, this laser was applied in the canine trachea to create a standard 5-mm diameter lesion through mucosa and submucosa. Power settings of 400 mJ and 600 mJ per pulse at 2 pulses per second were used, and wound healing was studied over a 2-week period. Excellent control of depth of tissue ablation was noted, with uncomplicated wound repair. Although healing was somewhat slower compared with healing when the CO2 laser was used, less granulation and fewer inflammatory changes were noted.

The Holmium laser has been found to be a safe, effective arthroscopic tool for peripheral joint surgery. Its multiple applications, small probe size, fiberoptic capability, and fluid medium transmissibility with pulsed, freebeam delivery offer significant advantages over electrocautery and laser systems developed for other biomedical applications. The 2.1 µm wavelength appears to ideally suited for arthroscopic use, and the recent development of improved delivery devices and the new high power output 32W system will continue to provide greater versatility and speed of use and will broaden an already seemingly limitless scope of applications.

Regardless of the method used, the time required for a patient to return to function was approximately 4 weeks. With all factors being considered, this study lends support to the use of Ho:YAG or CO2 lasers as an effective means for arthroscopic partial meniscetomy or chondroplasty. It is unlikely that lasers will completely replace mechanical instrumentation in arthroscopy; however, they are quickly becoming a useful addition to the armamentarium of arthroscopists.

This relatively new form of laser energy, with its powerful and precise ability to ablate the dense tissues of the musculoskeletal system as well as its transmissibility in fiberoptic cables and a fluid medium, makes this an ideal tool for use in orthopedic surgery. Its importance as a new orthopedic modality may well lie in its unique ability to gain access to small articular compartments while providing superior homeostatic control, thereby decreasing postoperative morbidity. While not yet in widespread use, its popularity is rapidly spreading and research into a variety of new applications is growing steadily.

The authors report their experiences using the excimer laser and Holmium:YAG laser in arthroscopic meniscal surgery. Histologic and ultrastructural aspects caused by laser irradiation on meniscal tissues are evaluated. Two groups of 10 patients, each suffering from a bucket-handle lesion of the internal meniscus, were used for this study. The histologic results of the study confirm the clinical reliability of the laser even in the presence of different ultrastructural frames.

A group of orthopedic surgeons is working assess the use of the Holmium:YAG laser in correcting glenohumeral instability. By using the laser to "shrink" tissue in the shoulder capsule, function and mobility are restored to patients. The procedure, dubbed laser assisted capsular shift (LACS), is being described as a "potentially promising alternative" to the variety of techniques that currently address glenohumeral instability.

A retrospective study was conducted in which several parameters of postoperative recovery were compared between 2 groups of patients: 25 patients who had lateral retinacular release surgery in which the Holmium:yttrium-aluminum-garnet (Ho:YAG) laser was used, and a control group of 17 patients who had the same surgery in which electrocautery was used. Postoperative recovery times of patients treated with the Ho:YAG laser were significantly decreased as compared with the recovery rates of patients in the control group. Morbidity also was reduced in the group for whom the laser was used. The results of this study indicate that the 2.1 micron wavelength, pulsed Ho:YAG laser can be used safely and effectively to perform lateral retinacular release surgery.

The Holmium LACS procedure appears to represent a unique minimally invasive treatment for shoulder dislocation. Future applications may include malalignment between kneecap and the femur and torn knee cartilage. The laser is also being explored in treatment of temporomandibular joint disease, in which the jaw bone and the temporal bone of the skull grate against each other causing extreme facial pain and headaches. The Holmium laser is a powerful yet precise and safe tool easily adapted for use in arthroscopic surgery. Thermal modification of capsular tissue by this procedure may be useful in treating GHI resulting from capsular redundancy. Further study is in progress to optimize tissue shrinkage and tissue strength.

Because of the low level of postoperative pain, the absence of adhesions and the almost complete lack of swelling, the patients treated with the Holmium:YAG laser and without electrocautery were able to regain full range of shoulder motion sooner than those treated with shaver and electrocautery.

Since the early 1980s, different groups of researchers have tried to develop arthroscopic laser surgery. Laser technology may be ideal for use in arthroscopic surgery, because laser instruments are extremely small but remain powerful. Currently, the 2.1-µm holmium:YAG laser and the 1.44-µm neodymium:YAG laser are considered to be the systems that provide better results: postoperative bloody effusions have been reduced and recovery times have been improved. Laser meniscectomy has been compared with conventional meniscectomy in several clinical studies, including the prospective study of the International Musculoskeletal Laser Society (IMLAS) knee research group. No studies have yet shown whether results are significantly improved by the use of a laser. As a single instrument, lasers can cut, coagulate, and ablate, depending on the method by which the laser energy is applied. It is the instruments themselves, not the procedure, that represent the most significant improvement. When used properly, lasers offer the arthroscopic surgeon the potential to decrease hemarthrosis, iatrogenic articular damage, and postoperative morbidity. Nevertheless, laser enthusiasts must exercise caution and specific procedures must be analyzed before arthroscopic laser surgery can be deemed better than conventional arthroscopic surgery. This is the aim of the IMLAS and its scientific board, under whose jurisdiction prospective studies are being conducted.

The in vitro study presented helps to clarify the biophysical mechanism and tissue interactions of the holmium laser at the point of impact on the surface of cartilage-bone specimens in different experimental settings. A striking event is the creation of a vapor bubble that opens up access for the laser beam through the fluid medium. This bubble shows a reproducible dynamic behavior function of the laser irradiance and the angle of incidence of the delivery fiber. These determine directly the amplitude of the pressure waves induced when the bubble collapses. Apart from this acoustic effect, which is correlated with epicentric histological features that can hardly be considered biologically relevant, a thermal effect is recognized that is finally responsible for the ablation and tissue damage. It induces typical histological alterations that can be observed along the laser beam axis, with a penetration function mainly of the irradiance but also of the angle of incidence. Nevertheless, at a pulse energy of 1J and an irradiation angle of 30 degrees, the recorded overall depth of the immediate histological changes was down to 500-600 µm. Thus, in realistic working conditions, the damage observed after cartilage sealing with the holmium laser remains within an absolutely acceptable range. This is in agreement with the better results compared to mechanical cartilage debridement that have been reported in previous prospective clinical studies.

The aim of this study was the dynamic measurement with magnetic resonance imaging, of temperature in cartilage irradiated by laser. Fresh specimens, each with chondromalacia grade II and III, were irradiated with a Holmium:YAG laser under MRI control. Temperature was measured by means of a proton-shift method, which allows high temporal and spatial resolution. With this method, a maximum increase in temperature of 35 degrees was found after irradiation with 1.0 J and 10 Hz for 5 sec. at a distance of 1 mm. In not case at all was an increase in temperature of more than 10 degrees observed in the cartilage adjacent to the subchondral bone. These results exclude the possibility of significant thermal damage from laser treatment as described.

Orthopedic surgeons have recently adapted the holmium:yttrium-aluminum-garnet (YAG) laser for the shrinkage of capsular tissues for treatment of glenohumeral instability. The molecular mechanism of capsular shrinkage has not been documented to date. This study examined the effects of heating on bovine calf knee capsule and subsequent shrinkage of the capsule. Capsule specimens were placed in a saline bath at temperatures ranging from 55 degrees to 75 degrees C for 1, 3, 5, and 10 minutes. Shrinkage was quantified by digital imaging, and the tissue was examined by light and polarized light microscopy. Tissue contraction was not measurable at or below 57.5 degrees C. At 60 degrees C, tissue shrinkage occurred with corresponding basophilic staining and loss of birefringence in collage fibers. For specimens heated at 60 degrees C and 62 degrees C, shrinkage directly correlated with duration of thermal exposure. Maximal shrinkage of approximately 50% in length occurred at and above 65 degrees C with thermal exposures of 1 minute or greater. This study demonstrates that thermal shrinkage of bovine knee capsule correlates with denaturation of collagen fibers and depends on both time and temperature. Capsular shrinkage treatments may be performed with any energy source that is capable of well-controlled heating of capsular tissue and does not depend on the special properties of laser light.