- About IMLAS
(Report By Daniel Choy, M.D.)
IMLAS was founded in Paris, April by a small group of orthopedic surgeons who had attended an initial meeting devoted to lasers in orthopedics at the University of Hannover in September 1991. The person most responsible for this effort, Dr. Werner Siebert, is presently Hospital Director of the Orthopaedic Hospital Kassel in Kassel, Germany.
The society is open to specialists of all disciplines interested in therapeutic use of lasers in musculoskeletal conditions and has grown rapidly from just a few organizing members to over 170. Applications for membership can be obtained from : Angie Faust, IMLAS, Wilhelmshöher Allee 345, D-34131 Kassel, Germany, Tel: D-561/3084-246, Fax: D- 561/3084-204
W. Siebert organized the 3rd International IMLAS Congress in Kassel. The first meeting was held in Neuchâtel, Switzerland, September 1994 presided over by Dr. B. Gerber. The second meeting was held at Lake Tahoe, chairman Dr. St. Abelow.
The Kassel meeting was divided into two minor and two major groupings. The first day was devoted to live TV coverage of laser operative procedures in arthroscopy of joints and neural foraminae of spine and non-endoscopic laser decompression of spinal discs. Moderation was in German primarily for the benefit of a large contingent of German surgeons. On days 2 and 3, smaller lecture sessions were devoted to basic science and low level laser therapy directed at trigger and acupuncture points. The writer did not attend the later sessions and can only quote from the abstracts that LLL (low level laser) is alive and well in Europe. The basic science sessions did not reveal much that was not previously known with exception of four papers:
1. In vitro and in vivo laser disc experiences in an open MR scanner by K. Zweifel et al. described the signal and temperature changes in human cadaver discs and discs in human patients subjected to Ho:YAG laser. The temperature changes were seen before the signal changes. Optical properties of human lumbar intervetebral disc - W. Glinkowski et al. A spectrophotometric determination of absorption peaks of lumbar discs: 3 zones (236 - 269 nm, 1390 - 1495 nm and 2407 - 2597 nm for nucleus pulposus, for annulus fibrosus it was 223 -393, 1397 - 1475 nm and 2439 - 2600 nm). The data for the annulus is of academic interest only since the nucleus pulposus is the target tissue. It can be seen that the Nd:YAG (1964 nm) and the Ho:YAG (2100 nm) are the closest. The KTP, at 532 nm, is perhaps the wrong laser for disc ablation. Experimental comparison of Nd:YAG, Ho:YAG and Diode laser ablation of intervertebral discs - Y. Ichimura et al. revealed data compatible with the writer's own experience. All three laser wavelengths could ablate significant portions of the nucleus pulposus with equivalent energy discharges. The Ho:YAG created the largest defect and the Diode laser created the greatest temperature rise. The Nd:YAG was intermediate. This paper was also presented in poster form and won the prize as best poster.
2. Photochemical tissue welding with 1,8 Naphthalimide dyes: in in-vitro and in-vivo meniscal and cartilage welds - R.W. Jackson et al. Strong instant welds were created in severed menisci and cartilage (shear strength of 1.8 kg/cm2 for meniscal tissue and 1.2 kg/cm2 for cartilage) by laser activation of edges prepared with dye. This work has significant possible clinical applications both for joint and annulus repair, and in the writer's opinion, perhaps for vessel and nerve anastamosis.
The two main clinical sessions were devoted on day 2 to arthroscopic applications of laser and on day 3 to spinal laser treatment.
There were a number of papers by authors T. Vangsness, G. Thabit, P. Hardy, M. Kunz, R. Marcan, A. Imhoff on a new frontier in laser applications in orthopaedics called "LACS" or laser assisted capsular shift, based on the ability of laser energy to shrink collagen. This is used primarily to shrink joint capsules in such conditions as recurrentshoulder dislocation, unstable knee joints, etc. The writer wonders about its application to MarfanÆs Syndrome and Ehlers-Danlos syndrome.
Joint synovectomy in rheumatoid and experimental arthritis is achievable by PDT, so far, in human knees and in a rabbit model. C. Hendrich et al. and J.L. Seara et al. read papers in this important area.
P.Hardy found no difference in clinical results comparing laser to mechanical meniscectomy.
O.S. Atik as well as H.H. Sherk found no osteonecrosis caused by laser during arthroscopic surgery. It is the inadequately trained surgeon who does.
Spinal Laser Treatment
Percutaneous Laser Disc Decompression since its creation in February 1986, has come of age.
Papers by B. Schlangmann, K. Zweifel, K. Diehl, S. Lee, M.T.N. Knight, D.S.J. Choy, B. Gerber, A.- Skuginna, J.R.T. Manazares, J.F. Ramirez Leon, R. Kosaka, T. Maruyama, R. Kayser, P.N. Kondoyannis, V. Pisot, D. Niezold, W.E. Siebert, Y. Nishijima, R. Stncker, S. Lee, G.D. Casper (only the senior authors are listed) reporting on 4560 patients treated with the Nd:YAG, Ho:YAG, and KTP lasers showed an average of 75% success rate, <0.5% complication rate. All reported a short operating time and an early return to work time. Two papers reported no decrease of disc height and no spinal instability after PLDD.
Patient selection for PLDD is being expanded by the introduction of endoscopic laser foraminoplasty (ELF) in which nerve root compression at the neural foramina by extruded disc, bony encroachment, etc. can be treated with endoscopic guided laser (Ho:YAG) with the patient awake, to warn of nerve injury. the leaders in this expanded use of PLDD are G.D. Casper, W.E. Siebert, M. Knight, B. Gerber, R. Stncker and S. Lee. It should be noted that the procedure is technically demanding, to be performed only by surgeons thoroughly trained in preceptorships.