Jiri Hubacek, Olomouc, CZ

 

With regards to the article of Miroslav Prochazka¹⁾, M. D., head doctor of the private Jarov Rehab Clinic in Prague, CZ, several facts should be mentioned in order to specify the matter. The clinic has accomplished excellent results and high professional level, hence my comments are intended to add some literary data and personal clinical experience.

The assertion that "at the outset of laser therapy only devices falling in class 3A, usually He-Ne devices with power output not exceeding 3 - 5 mW, were manufactured" is just a part of reality. The output of He-Ne lasers, 632.8 nm, which we had been using in therapy at the ENT Clinic in Olomouc, CZ, since 1980 was 30, 70 and even 100 mW. Delivering the beam through a lightguide can cause loss of energy, sometimes significantly high. Thus the real output of our 30 mW He-Ne laser was 10 mW at the end of the fibre,  70 mW laser emitted in fact 25 mW, and the 100 mW unit delivered 40 mW of real power at the end of the lightguide. Later on, He-Ne lasers have been replaced by 670 nm diode laser devices, predominantly 30 mW. For deeper penetration into tissue 830 nm IR lasers were utilized, at first 30 mW, later with 120 and 300 mW output power.

In LLLT it is necessary to know whether collimated or divergent beam is used, with or without a focus, as well as to calculate what energy density the target organ will be stimulated with.

The author`s contentions that "the Arndt-Schultz law applies (and not quite unambiguously) only to in vitro experiments with cell cultures" as well as that "in clinical practice it must be stressed, on the other hand, that the higher therapeutic dosage of energy is irradiated, the better therapeutic result is achieved" correspond neither with numerous literary information, nor with our experience, contradicting even the author`s own papers.

With regards to literature, it is necessary to mention scientific papers by E. Mester, quoted by Dr. Prochazka. In the course of his scientific stay in the USA professor Endre Mester, an outstanding surgeon, got acquainted with treatment of melanoma with pulsed ruby laser. Having returned to his home clinic professor Mester used a ruby laser to treat a woman with an inoperable melanoma. However, the therapy failed the patient dying of melanoma metastases. Professor Mester and his team, trying to find more ways how to utilize his laser, then started following biostimulation effects of ruby laser, and later on (according to oral representations of his sons during my stay in Budapest) also effects of argon and He-Ne lasers. One of his first observations related to the effects of radiation of ruby laser on growth of mice coat²⁾. Irradiation with 1 J/cm² once a week supports the coat growth after 5 - 6 applications, however after 10 - 11 irradiations the hair growth is suppressed. Furthermore, a single one-shot dosage of 10 J/cm² inhibits the growth.

According to Mester the effect of laser irradiation^3,4) depends on several factors: wavelength, output power and time of exposure. Biological effects of repeatedly applied irradiation accumulate, and once a certain level is reached suppressive effect comes. This phenomenon corresponds to the rule formulated by Arndt and Schulze, i.e. that lower dosages stimulate the growth of cells up to a certain limit, whilst higher dosages inhibit. The best experiment to support the Arndt-Schulz rule has been executed on experimental animals.

Stimulative and inhibitory effects of laser radiation depending on irradiated energy could be corroborated through monitoring fagocytary activity of polymorphonuclears and monocytes, as well as through comparation of changes in adherence and through INT test of fagocyting cells ^5,6). The results are in harmony with the Arndt-Schultz rule.

Prochazka declares that clinical failures are mostly caused by under-dose. We can agree to that, however it is necessary to specify the extent of an effective therapeutic dosage for individual pathologies, the number of applications as well as the intervals between them. The time needed for the energy density (J/cm²) to be reached is underestimated. The industry manufactures lasers with higher and higher power output and those are sometimes preferred in clinical practice. It is advantageous as such lasers save time of therapists. On the other hand, we should bear in mind that laser irradiation requires aslo a certain time duration in order to be able to have an impact on the cells or tissue.

The weightiest Prochazka`s argument is that "in clinical practice we must expressly declare that the higher the dosage of irradiated energy, the better the therapeutic effect." This assertion must not be mixed with the fact that in case of deep applications significant loss of energy due to passage through tissue structures must be taken into account, whilst, at the same time, sufficient amount of energy must be irradiated into, and absorbed by, the target structures. According to my own measurements (in colaboration with P. Goldmann) on fresh preparations of temporal bones hardly 1 per cent of energy (830 nm IR laser) can penetrate to the area of cochlea through processus mastoideus.

At the ENT Clinic of the Olomouc Hospital we have set recommended energy density, kind of laser, number and technique of application for ENT applications, based on experimental findings and empiric observations ^8,9,10).  We have verified that in the event of wounds healing and inflammations treatment therapeutic success was not achieved through increase of energy density or number of applications. The only exception is pain management.

The statement that "the higher the dosage of irradiated energy, the better the effect of therapy", cannot be generallized. It would be more appropriate to specify the indication range and support the results with more accurate data.

Prochazka et al. have published a number of papers on therapy of tinnitus. Some of the results are contrary to his claims.

In 1995 Prochazka and Hoppe ¹¹⁾ treated patients with tinnitus caused by reflexive mechanisms, usually by functional disorders of neck vertebra. Comprehensive rehabilitative care was supplemented by a laser with at least 30 mW power output. Irradiation with frequency modulation 9.12 Hz after Nogiér was aimed at the area of inner ear through processus mastoideus with energy dosage 10 - 16 J/cm² per procedure. They reported improvement in about 70 per cent cases, full relief in 20 per cent cases. Low number of patients were not sufficient for a serious evaluation.

In 1998 Prochazka ¹²⁾ reports, even though in a little number of patients, about 60 per cent success in terms of full relief, however in subjective evaluation of mitigation of intensity and frequency of tinnitus. Therapy was based on comprehensive rehabilitative care, administration of vasoactive medicaments, ev. Wobenzym, and irradiation with an IR laser its power being not less than 30 mW, applied in empirically tried combination of continuous beam and frequency modulation in 10 Hz or 9.12 Hz according to Nogiér`s pulses. Irradiation with a sufficiently high therapeutic dosage of at least 6 J/cm² is necessary.

In comprehensive therapy of tinnitus, as mentioned in later publications ^{13, 14)}, significantly higher dosages of energy were administered. An IR 300 mW laser probe applied 90 J/cm² energy density continuous beam (cw) on processus mastoideus, followed by 45 J/cm² modulated in 5 Hz. Subsequently, through external duct 50 J/cm² cw and 25 J/cm² in 5 Hz was applied in one session.

In Prochazka`s work with Tejnska ¹³⁾ the results in 33 patients evaluated after 8 - 10 sessions were as follows: 19.4 % no effect, 19.4 % relief less than 50 per cent, 35.5 % relief more than 50 per cent, 25.8 % no tinnitus.

Prochazka and Hahn ¹⁴⁾ followed 200 patients. Above mentioned energy density was applied 2 - 3 times a week in the first series, 8 - 10 sessions in total, and after a time period of 2 - 3 months other series follow with 5 - 6 applications once a week, total of not less than 5 series. Results: 16 % no effect, 15 % relief less than 50 per cent, 43 % relief more than 50 per cent, 26 % no tinnitus.

The first two papers are conceived as informatory works, some data are missing, however the following papers are very exact and therefore general results can be hardly compared. Nevertheless, it is apparent that best results had been achieved with a 30 mW probe with a very low energy density¹²⁾, though on a little group of patients.

In the book "Non-invasive Lasertherapy" published in 1997 ¹⁵⁾ Prochazka was the author of the chapter "Non-invasive Laser Therapy in Rehabilitation and Orthopedics". He tends to application of energy dosages 5 - 6 J/cm² in treatment of locomotive apparatus, otherwise recommended energy density is 2 - 4 J/cm², and in case of treatment of distortions and muscle contusions immediately after the injury up to 1 J/cm² is sufficient.

In 2000 in the second edition of the book (Modern Phototherapy and Lasertherapy⁷⁾) in the chapter "Non-invasive Laser in Treatment of Pain" Prochazka considers irradiated energy density 10 - 20 J/cm² to be a minimum, commonly using values around 50 J/cm² and even higher. Higher dosages relate to development of laser technology, significantly changing clinical results. However, no comparison of results of therapy in individual complaints is given.

Prochazka`s use of class IV laser in non-invasive laser indicationsis, after defocusing or scanning the beam, is an inspiring and meritable act. At first he had been using a CO2 laser in treating painful joints and entezopathias, later on a 4 Watt diode laser with 980 nm and 810 nm wavelengths. This therapy has proved successful in clinical practice, further in patients in whom a classical therapeutic laser had no success. A pioneer of this method is professor Mester, in our country Ina Hoppe had been trying to treat algic conditions with a defocussed CO₂ laser.

It is interesting to compare views of two pioneers of laser therapy in surgery (Aronoff) and in non-invasive medicine (Chronov) in the period of gaining their experience.At the 1st World Congress on Laser Surgery in 1975 Aronoff ¹⁶⁾ at the end of his paper on the use of CO2 laser in head and neck surgery stated some of his doubts:

1. Does a laser pay off? Will so much blood be saved  during surgical operations in order to compensate the costs of a laser device? Some authors claim to achieve the same effect using modern electrocauters. However, Aronoff does not consider important this, his main concern is whether laser proves to close lymphatic vessels better than electrocoagulation.
2. Does a laser hold a constant energy output? Aronoff observed apparent variation of power output during the same types of surgeries, therefore recommending to ensure periodical power check.
3. How accurate can we be using a laser for operations? Aronoff pleads for a pilot beam be implemented in surgical lasers, as well as for surgical microscopes be adapted not only for laser surgery of larynx but also of nerves and vessels.

In 1974 and 1979 ¹⁷⁾ Chronov critically evaluates so far published papers on biostimulation effects of lasers forewarning of impetuous application of laser therapy in clinical practice till therapeutic results are objectively reviewed. He concluded his reasoning as follows:

1. The number of published observations has not been extensive, groups of treated patients have been small so far, long term intervals and comparison with other time-tested methods are missing.
2. A number of authors reporting on effects of laser therapy often argument with impressions instead with objective evidence.
3. There is a great incongruity in crucial issues, such as energy density, number of applications and intervals between individual applications.
4. Do those therapists apply overall irradiation, local irradiation, or irradiation of acupuncture points?
5. It is necessary not to conceal complications, foresee and avoid them.
6. It is necessary to compare effects of different types of lasers and search for optimum therapeutic procedures.

It is Aronoff who can be after nearly thirty years of laser surgery happy about the outcome, as Cromov`s contemplations has been satisfactorily fulfilled only in the number of publications.

Literature

1. Procházka, M.: Laser třídy IV v indikacích neinvazivního laseru. Laser Partner 69/2003, s. 1-3, Praha.

2. Szzende, B., Mester, E., Tota, J.: Frakcionáltan adagolt lasersugár biologiai hatásának summalódsa. Kisérl. Orvostud., 21, 1969, 5, s. 477-478.

3. Mester, E., Tóth, N., Mester,A.: The biostimulative effect of laserbeam. Sborník Laser Tokyo, 81, 22, s. 4-7.

4. Mester,E.: Der biostimulative Effect von Laserstrahlungen. Z. Exper. Chirurg., 15, 1982, s. 67-74.

5. Hubáček, J.: Některé teoretické aspekty laserové biostimulace. Laser Partner 1/1999, s. 1-3, Praha.

6. Hubáček, J.: Zkušenosti s využitím terapeutického laseru v ORL praxi. Laser Partner 22/2000, s. 1-8., Praha.

7. Kolektiv autorů: Moderní fototerapie a laseroterapie, Manus, Praha 2000, 227 s.

8. Plouzhnikov, M. S., Lopotko, A. I., Gagauz, A. M.: Lasery v rinofaringologii. Kišiněv, Štiinca 1991, 157 s.

9. Simunovic, Z.: Laser in Medicine and Dentistry. Vitagraf, Rijeka 2000, 544 s.

10. Tunér, J., Hode, L.: Laser Therapy, Prima Books AB, Grängesbert, 2002, 570 s.

11. Procházka, M., Hoppe, I.: Komplexní rehabilitační péče o pacienty s tinnitem. Amireport 2/95, s. 69-72.

12. Procházka, M.: Neinvazivní laser v komplexní terapii tinnitu. Sborník: Pokračující hurz IPVZ, Rajnochovice 16. – 18. 10. 1998.

13. Procházka, M., Tejnská, R.: Neinvazivní laser v terapii tinnitu. Laser Partner č. 4/2000, s. 1-3., Praha.

14. Procházka, M., Hahn, A.: Komplexní laserová rehabilitační terapie tinnitu-dlouhodobá dvojitě slepá studie se souborem 200 pacientů v průběhu 3 let. Laser Partner č. 51/2002, s. 1-10., Praha.

15. Kolektiv autorů: Neinvazivní laseroterapie. Manus, Praha 1997, 148 s.

16. Aronoff, B.L.: The CO₂ Sharplan surgical laser in head and neck surgery. Sborník Laser in Surgery, Jerusalem, Jerusalem Academia Press 1976, s. 54-62.

17. Chromov, B. M.: Lazernaja terapija zabolevanij i pobreždenij. Vest. Khir., 1979, 1,s. 115-118.