Principles of Shock Wave Therapy

[문형철]

deep friction문제를 해결하는데 충격파치료기가 효과적이다.

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Principles of Shock Wave Therapy.pdf

A shock wave is a transient pressure disturbance that propagates rapidly in three-dimensional space. It is associated with a sudden rise from ambient pressure to its maximum pressure. A significant tissue effect is cavitation consequent to the negative phase of the wave propagation. The current authors summarize the basic physics of shock waves and the physical

parameters involved in assessing the amount of energy delivered to the target tissue and in comparing the various high- and low-energy devices being eval‎uated clinically for musculoskeletal applications.

For the past 10 years this technology has been increasingly applied to a broad range of musculoskeletal conditions.7,19 These applications include calcific tendinitis of the shoulder, nonunion, and delayed union of fractures.19,20 These applications initially stemmed from the concept of disintegrating calcifications in the shoulder that were similar to lithotriptic renal stone disintegration.25 The fracture application was chosen based on observations obtained during animal lithotripsy studies of the biologic tissue effects of shock waves, namely that shock waves striking the pelvis elicited a significant osteogenic response.

Electrohydraulic Principle

Shock wave generation through the electrohydraulic principle represents the first generation of orthopaedic shock wave machines (Fig 2A). The device acts in a similar way to the spark plug of a car. A high voltage from a charged caplug), which discharge rapidly across the spark-gap as the first focal (F1) point within a water-filled ellipsoid reflector. The resultant spark heats and vaporizes the surrounding water, thereby generating a gas bubble filled with water vapor (gas) and plasma. The expansion of this bubble produces a sonic pulse, and the subsequent implosion a reverse pulse, manifesting as a shock wave. The concentrically (spherically) expanding shock wave is reflected by the surface of the ellipsoid and is then refocused into the second focal point (F2) of the system (Fig 3). Geometry and the exact positioning of the device ensure that the second focal point is within the desired therapeutic anatomic region. Electrohydraulic shock wave devices usually are characterized by fairly large axial diameters of the focal volume and high total energy within that volume (Fig 4).

Electromagnetic Principle

The second device uses an electromagnetic coil and an opposing metal membrane (Fig2B). This technique of producing shock waves first was described by Eisenmenger.8 An electric current is passed through a coil to produce a strong magnetic field. A high current pulse is released through the coil, generating a strong, variable magnetic field, which, in turn, induces a high current in the opposed metal membrane. This strong magnetic field then causes an adjacent, highly conductive membrane to be forced rapidly away, thus compressing the surrounding fluid medium to produce a shock wave. A lens is used to focus the wave, with the focal therapeutic point being defined by the focal length of the lens. The amplitude of the focused wave increases by nonlinearities when the acoustical wave propagates toward the focal point.

Piezoelectric Principle

A large number (usually 1000) of piezocrystals is mounted on the inside of a sphere and receives a rapid electrical discharge (Fig 2C). This causes deformation (contraction and expansion) of the crystals (piezoelectric effect),

which induces a pressure pulse in the surrounding water steepening to a shock wave. The geometric arrangement of the crystals along the inside of the sphere causes self-focusing of the wave toward the center. This leads to an extremely precise focusing and a high energy density within a well-confined focal volume.

[professional Lee]

장비에 따라 효과도 많이 다릅니다. 전혀 효과가 없는 장비도 많습니다. 일반 병원에서는 치료효과를 내기위해 스테로이드와 리도케인을 적절히 혼합한 주사를 환부에 놓고 충격파를 시행하는 경우가 많습니다. 주사효과인지 충격파 효과인지 환자는 효과를 느끼기 때문에 만족합니다. 다만 재발의 위험성은 누구에게나 있습니다