Page Six P H Y S I O T H E R A P Y April, 1953 What is the Function of the Ultrasonic Therapy Compared with Short-Wave Therapy ? R eprinted from Siemens S R W -N ew s by kind perm ission o f Protea H oldings OF recent years, the therm ic effect o f ultrasonic treatm ent has been emphasized m ore and m ore in the course o f the discussions concerning the therapeutic m ode o f action o f ultrasonics; some authors (Bode, M atthes, Patzold, Theism ann) even claim that heat is' the essential agent o f ultrasonic therapy. C onsidering this situation, it is reasonable to ask w hether the use o f ultrasonic therapy— in so far as it can be considered purely as a thermic therapy— is still justified in view o f the existence o f shortwave therapy. In o rder to reply to this question, tw o points have to be considered in detail, namely :— 1. w hether the therapeutically effective agent o f ultrasonic therapy has a purely thermic character, and 2. in how far various thermic therapies may justifiably exist together. There is no doubt that, whenever an ultrasonic treat­ m ent is applied, p art o f the sonic energy is transform ed into heat in the tissues (although the resulting increases in tem ­ perature are often very slight), so th at m ore o r less con­ siderable thermic effects are attendant upon every u ltra­ sonic treatm ent. To this extent, then, the rem arks con­ cerning the im portance o f thermic effects are certainly justified. O n the o th er hand, however, we find certain ultrasonic effects which cannot be explained in terms o f therm ic action. F o r instance, the acceleration o f osqnotic processes should be m entioned here, which has often been observed and which, although certainly aided by increases o f tem perature, is evidently not dependant upon this factor alone, but also on mechanical processes (Barth, Baum gartl, Bruns, D enier, Frenzel, H insberg, H intzelm ann, Lehm ann, Pohlm ann, von Sanden, Schmid, Schultes). In th e field of practical therapeutical application it has also been pointed o u t frequently th at th e undoubted successes o f ultrasonic therapy, for instance in connection with Bechterew’s disease, crurai ulcers, scleroderm a and the healing o f wounds, cannot be explained merely in terms o f therm ic effects. In consequence, the existing m aterial does no t justify con­ sidering ultrasonic therapy simply as a special form o f therm ic therapy: direct m echanical action must be taken into account in every case. I f on exam ination o f th e first point it appears th a t the conception o f ultrasonic therapy as a pure thermic process is too limited, then it follows th at the second point m ust be reduced to an exam ination o f the therapeutical effects o f ultrasonic action as different from other methods o f thermic treatm ent. F o r this purpose, ultrasonic therapy, short-wave therapy and the application o f external heat (heating pads, h o t water bottles, hot baths, radiators) will be com ­ pared. W hen such a comparison is established, great differences are observed, both in respect o f general and particular characteristics. Fig. 1 gives a diagram m atic representation o f the heat distribution as it generally occurs when a p art o f the body is under treatm ent; the short-wave therapy with con­ denser field always has the character o f a “flow” through Fig. 1 - D iagram m atic representation o f heat distribution in a homogeneous body S h o r t - w a v e t h e r a p y w ith c o n d e n s e r f ie ld S k in S u b c u t a n e o u s fa t t y tissu e \ M u s c le s Bone S h o r t - w a v e t h e r a p y w ith c o il f ie ld Fig. 2 - D iagram m atic representation of heat distribution in the tissues R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) April, 1953 P H Y S I O T H E R A P Y Page Seven the whole p a rt o f the body; this method makes it possible by selecting a sufficiently large distance between the elec­ trodes and the skin, to concentrate the heat on the inner layers. W hen a coil field is employed toy m eans o f an “induction cable” , o r o f the “ d rum ” which is comm only used in the U .S.A .—the heat production is limited to the layers nearer the surface, but the width o f the heated zone is still considerable. U ltrasonic therapy, on the other hand, produces quite different conditions. H ere heat production arises only within a narrow beam o f sound waves (the half-value layer o f which is approxim ately 3 cm). W hen the usual massage m ethod is employed, moreover, the thermic action on individual points is only interm ittently effective. U ltrasonic application results therefore in greater localisation. The application o f external heat, on the other hand, has an effect only on the upperm ost layers o f skin, since no deep heat production can be obtained ; already a t a depth o f 6 to 8 m m , the increase in tem perature is merely 2° to 3° centigrades, even when the application is continued for a considerable period o f time employing, for instance, a compress at a tem perature o f 50° centigrade (Rein). D ue to the resulting increase o f blood circulation in the regions which lie near the surface, th e heat which is being applied is rem oved from the point o f application. In the other two methods, however, this process o f heat production and rem oval also reaches the deep layers to a great extent. I f we consider the heat distribution in different types o f biological tissue, we shall also find th a t definite dif­ ferences occur (see diagram in Fig. 2). W hen the condenser field m ethod is employed in short-wave therapy, the highest absorption o f electric energy and, consequently, the most intensive heat pro­ duction occurs, fo r the usual frequencies, in the sub­ cutaneous fatty tissue. W hen the coil field m ethod is applied, on the o ther hand, it is the muscle layers which lie near the surface which receive the highest therm ic action, because the coil field is a magnetic field, and heat production is the result o f eddy currents in these parts o f the tissues which are good conductors. The conditions in respect of ultrasonic therapy are again quite different; here it has been found th a t the therm ic action is m ost considerable near the boundary layers, and we have therefore zones o f maxi­ m um heat production at the boundary between the sub­ cutaneous fatty layers and thev muscle tissues, as well as a t the periosteum . T he application o f external heat, finally, is only effective in the zones nearest the skin, due to the m oderate depth o f penetration. A lthough this sum m ary refers only to some o f th e m ost im portant points in a very general manner, and can therefore certainly not do 'ju s tic e to various im portant details, it does however show convincingly that th e different methods o f thermal application considered are basically different not only in respect o f the m ode in which the heat is produced, but also—and this is the m ost decisive point— in the nature o f heat distribution in th e tissues o r parts o f the body under treatm ent. In consequence the reactions of the organism vary according to the m ethod employed. The question which we are considering here will there­ fore have to be answered in the sense th at ultrasonic therapy is im portant whenever direct m echanical action is required as an essential therapeutic agent. Several indications have already been m entioned which evidently belong to this category. Insofar as ultrasonic treatm ent is used mainly for therm al therapy purposes, it will be o f specific value in selective heating o f boundary layers, such as in the treat­ ment o f arthropathy o r o f inflam m atory processes near the surface (e.g. furuncles, sudoriparous abscesses, mastitis, paronychia, etc.). Practising doctors, moreover, emphasize again and again the superiority o f ultrasonic therapy in V////////////S777PZ* when different methods o f thermic application are used S k in S u b c u t a n e o u s fa t t y tissu e M u s c le s U lt r a s o n ic t h e r a p y when different methods of thermic application are used H e a t t h e r a p y w ith h e a t in g p a d R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) Page Eight P H Y S I O T H E R A P Y April, 1953 the treatm ent o f sciatica, neuralgia and neuritis, bu t the question remains unansw ered w hether the results are due to mechanical action or to the effect o f a specific tem perature distribution. T he sam e is true o f the well know n good results which can be obtained in connection with Bech- terew’s disease, scleroderm a and crural ulcers. Finally, the spasmolytic effect o f ultrasonic treatm ent seems to be superior to th a t o f an exclusively therm al therapy. While the localised action o f ultrasonic therapy, however, is limited to peripheral zones (or should, at any rate, be thus limited considering th at the deep action o f ultrasonic therapy is as yet too little known), deep action is precisely the outstanding characteristic o f short-wave therapy. Short-wave treatm ent is also to be preferred whenever it is desired to have a strong flow o f heat through a p art o f the body, since ultrasonics would result in periosteal pain at a com paratively early stage due to boundary layer heating. F rom this point o f view, then, short-wave therapy can advantageously be used when it is desired to send a flow o f heat through the tru n k o f the body, for instance in diseases o f the respiratory tract (such as bronchitis), o f the urogenital system (such as adnexitis or prostatitis), o f the abdom inal organs, etc. F urtherm ore, diseases in the head (e.g. o f the ear, o f the paranasal sinus) will always be treated by means o f short-wave application. A detailed discussion o f all the im portant points o f view affecting the questions set above would exceed the scope o f the present article. T he therapeutic “ rem ote effects” , for instance, as know n in connection with the cutivisceral reflexes in the application o f external heat have been completely ignored. Stiihlfauth was probably the first to point to the possibilities o f using the vegetative- neural tracts for purposes o f ultrasonic therapy, while Loeppen and Schliephake prefer to use the endocrine approach for short-w ave stim ulation o f the hypophysis. I t seems th a t the exploration o f the avenues opened up in these fields has ju st begun. M oreover, com bined treatm ent (for instance by using alternate therapies in the course o f a series o f sessions) or comprehensive therapy combining short-wave treatm ent o f the whole body (artificial fever) with local ultrasonic treatm ent (K oeppen) have hardly been tried o u t up to date. Finally, the definition o f the two methods is n o t to be understood in the sense th a t each m ethod m ust be strictly confined to its own indications. In the treatm ent o f neuritis, arthropathy o r furuncles, for instance, it will be found th a t some cases respond better to ultrasonic therapy, while others are m o r e . successfully treated with short-w ave therapy. T he short indications contained in the present article may, however, contribute to explain the point o f view of those practising doctors who are fam iliar with the use o f ultrasonic therapy, and who believe th at—after th e excessive use resulting from an ephem eral “ fashion” has subsided —ultrasonic therapy, with its well defined field o f applica­ tion, supplements short-wave therapy instead o f being its rival. Thus, ultrasonics constitute a valuable addition to the general therapeutic equipm ent o f medical science, and their use in practical medicine is now th at new simplified app aratus condensed to the essential details have been introduced, o f definite advantage. D r. K . v. Sanden SOUTH AFRICAN RAILWAYS AND HARBOURS SICK FUND Appointment o f Salaried Physiotherapist—Germiston A pplications are invited from registered Physio­ therapists for appointm ent to the position o f Salaried Physiotherapist, G erm iston, a t a salary o f £600 per annum , and w ith the right o f private practice. The salary will be subject to adjustm ent in accordance with the census o f members to be taken on the 1st A pril o f each year. The appointm ent will be m ade in terms o f the R egula­ tio n s o f the F und, and will be subject to term ination on four m onths notice being given by either side. The successful candidate will be required to reside at G erm iston, to take up th e appointm ent on a date to be arranged, carry out the duties in accordance w ith the R egulations o f the Fund, and to provide at own expense the necessary room s, equipm ent, etc. A pplications should reach the D istrict Secretary, W estern Transvaal D istrict Sick Fund B oard, R oom 342, New Station Buildings, Johannesburbg, not later than 2nd M ay, 1953, and should state , (1) F u ll name. (2) Qualifications (when and where obtained). (3) Experience (when and where obtained). (4) D ate o f birth. (5) C ountry o f B irth. (6) W hether m arried o r single. (7) W hether fully bilingual. (8) W hether South A frican citizen. (9) W hat governm ent appointm ent, if any, is held. Canvassing by o r on behalf o f any applicant is liable to disqualify such applicant. Any further particulars required may be obtained from the D istrict Secretary, a t the above address, on applica­ tion. P. J. K LEM , G eneral Secretary. JO H A N N E SB U R G , April, 1953. . D u e to a m o s t u n f o r t u n a t e m u d d lin g of t h e p ro o fs, th e a r t ic l e s u b m it te d b y M r. D a v id M u s k a t o n “F r o z e n S h o u ld e r ” in th e J a n u a r y issu e w as p u b lis h e d w ith th e s u b je c t m a t t e r in a n in c o r r e c t se q u e n c e . M o s t sin c e re a p o lo g ie s a r e p r o f f e r e d to M r . M u s k a t, a n d i t is to be h o p e d t h a t d e s p ite th is e r r o r , r e a d e r s w e re a b le to fo llo w h is m o s t i n t e r ­ e s t in g a r tic le . R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. )