as set forth above , it is one of the aspects of the present invention to treat hard tissues entrapped in a cavity comprising body fluids , wherein said cavity has a diameter of less than 3 mm so treatment of the hard tissue is achieved without causing a substantial heating of the fluid and the small sized fluid filled cavity . such a heating presents a major problem and prior the present invention prevented effective and safe treatment of hard tissues in such small cavities . prior to the present invention there was no satisfactory solution for the treatment of hard tissue entrapped in small , fluid - filled cavities , and there was no way to provide a treatment that would enable on the one hand , to disintegrate the hard tissue to small enough fragments to be easily flushed out , and on the other hand , to do so without substantial ( i . e . tissue damaging ) temperature increase in the fluid - filled small cavity . two examples are hereto provided , wherein the first is the treating of scars and other diseases and disorders in the temporomandibular joint ( tmj ). the second is treating of calcium stones , especially those located in the mandibular salivary ducts . those two examples and the following description which is provided below , along all chapters of the present invention , are described to enable any person skilled in the art to make use of said invention and set forth the best modes contemplated by the inventor of carrying out this invention . various modifications , however , will remain apparent to those skilled in the art , since the generic principles of the present invention have been defined specifically to provide the erbium yttrium - aluminum - garnet ( er : yag ) laser system . reference is made now to fig1 describing the tmj 1 located in the joint of the mandibular and maxillary bones . a magnified presentation of said tmj is presented to comprise of a connective tissue ( 2 a ) and a disc 2 ( b ). reference is made now to fig2 , schematically presenting the salivary glands : parotid duct 21 communicating the mouth with the accessory parotid gland 22 the parotid gland 23 and the submandibular gland 24 and the sublingual gland 25 . for endoscopic laser lithotripsy of salivary stones , it is determined that 85 % of salivary stones are located in the sub - mandibular gland 24 and 15 % in the parotid 22 , 23 glands . this is the area of the mouth and jaws . most stones are composed of calcium phosphate . typical size range is 5 - 20 mm . complete fragmentation requires fragments less than 2 mm , so that they can be effectively disintegrated . fig3 a shows the laser applied to the salivary glands of a patient 130 , and delivered through the mouth cavity . fig3 b shows reference block diagram 135 of the placement of the endoscope and the optic fiber in salivary ducts , wherein 137 is the stone , 138 is the endoscope and 136 the laser fiber . the endoscopes used such as in fig4 a and 4b may be a nahlieli type sialoendoscope , and delivery of said laser beam is by a curved optical fiber . the nahlieli sialoendoscope , as such as the device type 1 or 2 commercially available by karl storz ltd . this is an endoscope useful for the diagnosis and treatment of inflammatory salivary gland diseases and for minimal temporo - mandibular - joint arthroscopy ( denoted in the present invention in the term ‘ nahlieli type sialoendoscope ’). the hereto - defined storz &# 39 ; s nahlieli sialoendoscope usually comprising two separate channels , with two blunt obturators and two luer - lock adapters , curved channel for instruments up to 3 fr ., o . d . 1 . 3 mm , straight channel for use with the commercially available miniature telescope 28620 with lateral luer - lock adapter for irrigation , o . d . 1 . 3 mm , working length 4 cm , overall length 10 . 7 cm . reference is made now to fig4 a , presenting a side view of a karl storz commercially available nahlieli sialoendoscope , comprising a handle and blunt obturator , for use with a miniature telescope diameter 2 . 3 mm × 1 . 3 mm , working length 12 cm , and an operating sheath with obturator valve . similarly , fig4 b is presenting a side view of another commercially available nahlieli sialoendoscope comprising with two separate channels , with two blunt obturators and two luer - lock adaptors , curved channel for instruments up to 3 fr ., o . d . 1 . 3 mm , straight channel for use with miniature telescope with lateral luer - lock adaptor for irrigation , o . d . 1 . 3 mm , working length 4 cm , overall length 10 . 7 cm . it is in the scope of the present invention , wherein the laser is an erbiumyag laser . reference is now made to fig5 which shows an apparatus 500 which is part of a system for carrying out the invention . this apparatus is a focusing hand piece which attaches , at its proximal end 501 to a dental erbium laser delivery fiber 502 . the hand piece houses focusing lenses ( e . g . znse lenses ) 503 to focus the beam emitted from the laser fiber into the endoscopic fiber 504 . the endoscopic fiber 504 is attached at the distal end of the hand piece through a quick connect mechanism 505 such as an sma connector . the endoscopic fiber 504 is inserted into the operating channel of the nachlieli endoscope ( for example as shown in fig4 a or 4 b ). a luer lock ( not shown ) may be incorporated over the sma connector to firmly secure the fiber and the hand piece to the endoscope so that the surgeon may hold the entire device in one hand . fig6 illustrates an apparatus , generally at 600 , of the present invention configured and operable for use in arthroscopy . the apparatus 600 is configured generally similar to the above - described apparatus 500 , namely presents a focusing hand piece having its proximal end 601 coupled to an erbium laser delivery fiber 602 , and includes focusing lenses 603 for focusing the erbium beam into an endoscopic fiber 604 . the latter is preferably an integral part of the entire device 600 . in the device 600 , the endoscopic fiber 604 is configured according to the invention for effectively delivering erbium radiation towards a target while in the fluid - filled bodily cavity . to this end , distal end 611 of the hollow wave guide 604 is sealed by a sapphire tip 612 . the sapphire tip 612 is preferably mounted on the wave guide pipe 611 such that a small part of the tip 612 projects out of the pipe 611 or such that the tip 612 is entirely concealed inside the hollow wave guide 611 . this is shown in the examples of fig7 a and 7b . it should be understood that the smaller the projecting part the less damage ( affecting optical properties of the tip ) to the sapphire body 612 that might be caused by hits of ablated calculi particles . fig7 a and 7b also show that the distal end of the waveguide 604 may be wedged or substantially planar or arced . as further better seen in fig7 a and 7b , the waveguide 604 is made of a hollow pipe 614 made of a material reflective to wavelength radiation of 2700 - 3000 nm ( preferably metal pipe which may or may not be coated by another material external coating ), and its inner surface is coated with a dielectric material layer ( film ) 616 . erbium laser used for the tests was a commercial opusduo dental laser produced by lumenis ltd ., israel . this laser is a free - running , 2 . 94 μm laser which emits 250 μsec pulses at a maximum rate of 20 hz . energy per pulse can be adjusted from 100 mj to 1000 mj . maximum average power is 20 watt . the laser beam is delivered through a flexible , metal , hollow fiber to a handpiece which may be detached . beam spot size at the handpiece output aperture is 1 mm . some of the tests were conducted using the standard system handpiece fitted with short sapphire tips ( straight or tapered ) to deliver the energy to the stones while some of the tests were conducted using various commercially available infrared fibers such as sapphire fibers ( photran inc ., u . s . a . ), hollow glass fibers ( polymicro , u . s . a .) or germanium oxide glass fibers ( infrared fiber systems , u . s . a .). 1 mm . core fibers were “ butt ” coupled to the system handpiece while smaller diameter fibers were connected using znse lenses to focus the laser beam into the fiber . in vitro lithotripsy of human , extracted , salivary stones was conducted both in air and in water to test optimal fragmentation parameters . in air , 200 mj with a spot of 1 mm and a frequency of 20 hz resulted in efficient fragmentation to dust - like particles . energy increase to 300 mj appeared clinically to be too aggressive with substantially larger fragments . in all cases fragmentation was conducted in contact or close contact to the stone . while fragmentation was found to be clinically efficient , lithotripsy in an air environment resulted in rapid contamination of the fiber output surface by stone debris which caused fiber damage . even small salivary stones could not be fragmented before onset of this catastrophic damage mechanism . contamination persisted even with a fiber - stone distance of 3 - 4 mms . though efficiency decrease due to beam divergence out of the fiber . additionally large fiber - stone distances are endoscopically not practical . to overcome this problem , fragmentation was conducted in a water filled container with the fiber tip in contact with the stone . it was found that in a water environment fiber tip durability is increased even though laser energies have to be increased to obtain clinically efficient fragmentation rates . using a 1 mm spot size , threshold for clinically efficient fragmentation was found to be 300 mj per pulse , while optimal range was 500 - 700 mj per pulse . optimal pulse rates were 15 - 20 hz . stone fragmented to microscopic , dust - like particles which floated in the water , with occasional larger fragments ( 2 - 3 mm ) which broke off particularly from softer stones . the surface of a 1 mm . sapphire tip , in contact with the stone under water , did not exhibit any damage or degradation at all energy levels up to 1000 mj , the maximum energy available from the laser . use of the smaller fiber diameter resulted in more efficient fragmentation due to the higher energy densities , but resulted in fiber tip damage with some of the fibers used . the comparison was perform between er : yag laser and holmium laser the latter being the standard laser used for lithotripsy in urology . comparison was carried out in vitro , testing the size and nature of fragmentation of extracted , human salivary stones placed in a water filled metal container which was to simulate a small cavity filled with liquid . delivery of the holmium laser was through standard , commercial low - oh silica fibers . test confirmed literature report that fragmentation efficiency of erbium is roughly twice that of holmium . fragmentation rate of erbium at 10 hz , 0 . 5 j / pulse was similar to that of holmium at 10 hz , 1 j . these are the conventional holmium parameters used in clinical work . additionally test showed that stone fragments following erbium lithotripsy are smaller than with holmium . this was visually observed by the fact that for the same stones , most holmium fragments immediately sunk and accumulated at the bottom of the container while with the erbium , fragments floated in the water as a “ cloudy ” suspension . these results indicate that the method of the invention is more effective in disintegrating stones , in particular salivary stones , than treatment with holmium laser or other pulverization means . having described the invention with regard to certain specific embodiments thereof , it is to be understood that the description is not meant as a limitation , since further modifications will now suggest themselves to those skilled in the art , and it is intended to cover such modifications as fall within the scope of the appended claims . this example demonstrates the experimental results of using the device 600 ( fig6 ) of the present invention in a clinical procedure applied to a porcine knee ( device used employed a substantially flat - shaped sapphire tip slightly protruding out of the metal tube ). erbium laser radiation used was a commercial opusduo dental laser commercially available from lumenis ltd ., israel . the test procedure has been performed when the porcine knee being irrigated by saline solution . the laser beam was delivered from the laser source ( erbium laser ) to the target ( i . e ., the meniscus of the porcine knee ) through the waveguide 604 ( which may be detachable ). the operational mode was such that the beam spot size at the handpiece aperture ( i . e ., at that entrance of the lens arrangement 603 ) was 1 mm . the fiber probe 604 was a 14 cm in length and with an inner diameter of about 0 . 6 mm ). the distal end of the probe was placed in contact or very near contact to the meniscus tissue . generally , the treatment of the kind specified can be carried out with the laser pulsed radiation energy in a range of 200 - 2000 millijoule . in the present experiment , the erbium source operated in a pulse mode generating 300 mj pulses at a frequency of 20 hz , and during the device operation the meniscus of the porcine knee was incised in several tens of seconds . generally , the inventors have found that a treatment time may be from about ten seconds to a few minutes .
a method and probe device are presented , suitable for use in joint arthroscopy . a beam of pulsed laser radiation of a wavelength range of about 2700 - 3000 nm and a predetermined frequency of pulses is produced , directed to a joint region inside a fluid medium and maintained substantially focused on a treatment target within the joint region during a predetermined time period . by this , a tissue within the treatment target is effected by the laser radiation .