Abstract:
A noise dampening shroud is configured to surround the generator of lithotriptor device to reduce the noise emissions caused as a result of the generation of acoustic shock waves during extracorporeal treatment of a patient. The shroud comprises an insulating body and a cover. The insulating body comprises sound dampening insulation and is configured to surround substantially all of the housing that typically encases the generator of convention lithotriptors. The cover is comprised of a thin pliant material configured to surround the insulating body and is provided with fasteners for removably securing the insulating body to the generator. When attached to the generator of a lithotriptor device, the shroud greatly reduces the noise emitting by the generation of acoustic shock waves and thereby minimizes the distraction and disturbance caused by such noise.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to lithotriptor devices, and more particularly, to audible noise emissions from acoustic shock wave generators of such devices. 
     Lithotriptors are devices employed in medical and therapeutic extracorporeal treatment of humans and animals for the destruction of concretions (e.g. kidney stones), induction of bone growth, and treatment of other soft-tissues. These devices operate by producing focused acoustic shock waves capable of creating extremely high pressure differentials at localized regions within a patient&#39;s body that act upon targeted concretions or bodily tissue being treated. 
     Various types of lithotriptors utilize different means for producing acoustic shock waves. Such means are known in the art and include electromagnetic, piezoelectric, and electrical spark-gap generators. While the type of generator used to produce the acoustic shock waves varies from one lithotriptor to the next, each type of generator ultimately produces acoustic shock waves capable of being focused in a specific trajectory and at a certain depth. 
     Because the focal point or isocenter of a conventional shock wave generator is fixed, the generator of a conventional lithotriptor is typically encased in a housing suspended from a moveable arm such that the trajectory of the acoustic shock waves can be aligned relative to a patient receiving treatment. While the movable arm of the lithotriptor allows alignment of the shock wave trajectory, the depth of the shock wave within the patient&#39;s body is controlled by expansion and contraction of a fluid-filled cushion that extends through the housing and engages the patient&#39;s epidermis. 
     In addition to the arm and fluid-filled cushion extending from the generator housing, conventional lithotriptors may include a fluid supply line or hose extending from the housing to provide means for liquid cooling of the generator. Furthermore, the housing may have one or more mechanisms for aligning the isocenter of the acoustic shock waves relative to the patient. 
     Although lithotriptor devices have proven useful in medical treatment and therapy, such devices produce a significant amount of unfocused noise when generating the acoustic shock waves. Such noise results from the discharge of capacitors, generation of sparks, or other means used to create the acoustic shock waves. 
     In addition to disturbing those present in a room in which the device is being used, the audible noise emissions of the lithotriptors have been known to distract and disturb persons in adjacent or nearby rooms. This is especially problematic in modern operating rooms that often share a common sterile hallway with little or no means of preventing sound transfer between adjacent rooms. In such situations, noise generated by use of lithotriptor can disturb medical personnel performing intricate surgery in adjacent rooms. 
     SUMMARY OF THE INVENTION 
     Among the advantages of the present invention may be noted the provision of a noise dampener for reducing the audible noise emissions produced by the acoustic shock wave generator of a lithotriptor device, and the provision of a method of reducing the audible noise emitted from such a device. 
     In general, a noise dampener of the present invention comprises a shroud of sound dampening insulation configured and adapted to surround the acoustic shock wave generator of a lithotriptor device without interfering with the operation of the device. The shroud is connected to the generator and significantly reduces the noise emissions caused by the generation of acoustic shock waves when the lithotriptor is in use. 
     The preferred embodiment of the present invention is a removable shroud that can be repeatedly attached to, and removed from, the generator without damaging the shroud and without modification of the lithotriptor. The removability of the shroud of the preferred embodiment allows the shroud to be removed when utilizing alignment mechanisms or other similar devices that would otherwise be covered by the shroud when the lithotriptor is in use. 
     Another aspect of the present invention is a method of reducing the audible noise emitted from the generator of a lithotriptor device. The method comprises surrounding the generator with sound dampening insulation without interfering with the operation of the lithotriptor. 
     Other features and advantages will be in part apparent and in part pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a shroud of the present invention showing an insulated body surrounded by a cover. 
     FIG. 2 is an isometric view of the insulating body of FIG. 1 shown by itself. 
     FIG. 3 is a partial isometric view of a conventional lithotriptor device. 
     FIG. 4 is a partial isometric view showing the shroud of FIG. 1 attached to the lithotriptor device of FIG.  3 . 
     Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, and first more particularly to FIG. 1, a shroud of the present invention is indicated in its entirety by the reference numeral  10 . The purpose of the shroud  10  is to reduce the audible noise emitted from a generator of a lithotriptor as it produces acoustic shock waves during extracorporeal treatment. 
     For purposes of describing the preferred embodiment of the invention, it is necessary to first describe the generator of the lithotriptor for which the shroud  10  is preferably configured and adapted for use. However, it should be understood that the invention is not limited to use with a specific type or model of lithotriptor and one skilled in the art, having knowledge of the present disclosure, could practice the invention in connection with various lithotriptor devices. 
     The shroud  10  shown in this embodiment is preferably adapted and configured for use with a LITHOSTAR® MODULARIS® lithotriptor manufactured by Siemens Medical Systems, Inc. and shown in part in FIGS. 3 and 4. As shown in the figures, the generator of the lithotriptor, generally indicated at  12 , is encased by a generally cylindrical housing  14  and has an opposite top  16  and bottom  18 . A moveable arm  20  extending radially from the housing  14  supports the generator  12  and connects the generator to the remainder of the lithotriptor device (not shown). The movable arm  20  allows for positioning of the generator  12  relative to a patient (not shown) receiving treatment to align the trajectory of the acoustic shock waves with the intended target. The depth of the shock wave isocenter within the patient&#39;s body is controlled by a fluid-filled cushion  22  at the top  16  of the generator  12  that extends through the housing  14  and has an exterior transmission surface  24  configured to transmit the acoustic shock waves into a patient&#39;s body by engaging the patient&#39;s epidermis. 
     The specific lithotriptor described herein also incorporates an aligning mechanism  26  pivotally mounted to the housing  12 . When desired, the aligning mechanism  26  may be swung above the top  16  of the generator  12  for producing a focus phantom to facilitate proper positioning of the isocenter of the acoustic shock waves via x-ray imaging. During treatment, the alignment mechanism  26  is swung beneath the bottom  18  of the generator  12  where it will not interfere with the operation of the lithotriptor. 
     The generator  12  of the lithotriptor also has a fluid supply line  22  extending from the bottom  18  of the housing  14  for liquid cooling of the generator  12  when the lithotriptor is in use. As shown, the fluid supply line  28  is in the form of a flexible hose to accommodate positional movement of the generator  12 . 
     The shroud  10  of the invention preferably comprises an insulating body, generally indicated at  30 , and a cover generally indicated at  32 . The insulating body  30  comprises sound dampening insulation that is preferably in the form of a fibrous pad of the type disclosed in U.S. Pat. No. 5,952,248, the disclosure of which is incorporated herein by reference. However, it should be noted that the sound dampening insulation could also be formed from other suitable materials known in the art for use as acoustic insulators, in place of or in conjunction with fibrous padding. A cladding  34  of vinyl or other suitable material is preferably sewn around or otherwise attached to the insulating body  30  to reduce wear of the sound dampening insulation and facilitate cleaning of the insulating body. 
     The insulating body  30  is preferably formed as a single piece in a shape configured and adapted to substantially surround the housing  14  of the generator  12  without obstructing the fluid-filled cushion  22  at the top  16  of the generator. As shown by itself in FIG. 2, the insulating body  30  has a generally cylindrical wall  36  defining an inner cavity  38 . A top edge  40  of the cylindrical wall  36  forms a mouth to the inner cavity  38  while the opposite bottom of the inner cavity is substantially closed by a generally disk-shaped wall  42  of the insulating body  30 . 
     A slot  44  passes through both the cylindrical wall  36  and disk-shaped wall  42  of the insulating body  30  and preferably extends axially from the top edge  40  of the insulating body. The slot  44  preferably has a straight first edge  46  and a notch  48  formed in an opposite second edge  50 . A concave semicircular edge of the disk-shaped wall  42  joins the opposite first  46  and second  50  edges and forms a closed end  52  of the slot  44 . 
     The configuration of the insulating body  30  described above allows the insulating body to be slid onto the housing  14  of the generator  12  by placing the insulator body over the generator such that generator is received in the inner cavity  38  of the insulating body with the arm  20  and the fluid supply line  28  of the lithotriptor extending through the slot  44 . When the insulating body  30  is properly positioned around the housing  14 , the bottom  18  of the generator  12  is adjacent the disk-shaped wall  42  of the insulating body  30  with the fluid supply line  28  extending through the closed end  52  of the slot  44  and the arm  20  of the lithotriptor extending through the notch  48  of the slot. In such a position, the cover  14  of the shroud  10  may then be used to removably secure the insulating body  30  around the generator  12  of the lithotriptor. 
     The cover  32  of the shroud  10  as shown in FIGS. 1 and 4 is preferably comprised of a pliant material such as vinyl and is preferably similar in shape to the insulating body  30 . Like the insulating body  30 , the cover  32  preferably has a cylindrical portion  54 , a disk-shaped portion  56 , and a slot  58 . Furthermore, like the slot  44  of the insulating body  30 , the slot  58  of the cover  32  has a straight first edge  60  and a notch  62  in an opposite second edge  64 . 
     Unlike the slot  44  of the insulating body  30 , the second edge  64  of the slot  58  of the cover  32  is configured to overlap the first edge  60 . Two fastener mechanisms  66 , preferably comprising VELCRO® fasteners sewn to the cover  32 , are positioned adjacent the second edge  64  of the slot  58  on either side of the notch  62 . The fastener mechanisms  66  adjacent the second edge  64  of the slot  58  are configured to engage corresponding fastener mechanisms  68  adjacent the opposite first edge  60  to removably secure the opposite edges of the slot together. Finally, unlike the insulating body  30 , the cover  32  has an elastic member sewn into a top edge  70  of the cover that acts to constrict the top edge, drawing the top edge radially inward. 
     With the insulating body  30  positioned around the housing  14  of the generator  12  as described above, the cover  32  can be slid over the insulating body in a manner similar to the way the insulating body is slid over the housing. With the cover  32  in place around the insulating body  30 , the fastener mechanisms  66  adjacent the second edge  64  of the slot  58  of the cover can be secured to the corresponding fastener mechanisms  68  adjacent the opposite first edge  60  of the slot, as shown in FIG.  4 . By securing the fastener mechanisms  66 ,  68  to each other, the cover  32  conforms around the arm  20  and the fluid supply line  28  of the lithotriptor, and closes the remainder of the slot  58 . Additionally, the diameter of the cylindrical portion  54  of the cover  32  is dimensioned such that the cover squeezes the insulating body  30  to bring the first  46  and second  50  edges of the slot  44  of the insulating body toward each other. Finally, the elastic member of the top edge  70  of the cover  32  holds the top portion of the cover flush adjacent the top  16  of the housing  14  of the generator  12 . 
     Preferably, the shroud  10  is shaped, configured, and of a suitable material such that noise emissions from the housing  14  during operation of the generator  12  are dampened by at least a factor of five (e.g. 7 dB), and more preferably by at least a factor of ten (e.g. 10 dB), and yet more preferably by a factor of at least 20 (e.g. 13 dB) relative to undampened noise emissions. Furthermore, the shroud  10  can quickly and easily be removed and reattached to the housing  14  to facilitate use of the aligning mechanism  26  and service of the generator  12  without damaging the shroud. 
     In view of the above, it will be seen that several objects of the invention are achieved and advantageous results obtained. 
     As various changes could be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanied drawings shall be interpreted as illustrative and not in a limited sense.