Material and Method 
Our trial was carried out on 485 patients mostly admitted to Geriatric Institute Pio Albergo Trivulzio. Our report refers to patients treated for osteoarticular pain  due to pathologies frequently occuring in elderly people: reflex sympathetic distrophy of hemiplegic patients (140 patients), knee osteoarthritis (228 patients) and spine osteoarthritis (117 patients). 
The laser apparatuses utilized for therapy in our trial were the following (Fig. 1): 
1. CO2 Laser (ETOILE), wavelength 10.600 nm, continuous emission and output power 3.5 Watts. 
2. HeNe Laser (MECTRONIC), wavelength  632,8 nm, continuous emission, output power 7.3 mW, variable sweep speed ranging from 2.5 to 2.8 cm/sec. 
3. GaAs Laser (MECTRONIC), wavelength 904 nm, pulsating emission, repeated frequency signal from 0 to  5000 Hertz, equal at max frequency to an average output power 19 mW. The laser apparatus consists in a control consolle and two hand-held delivery probes, connected to the consolle by two flexible cables. 
4. GaAs Laser (MECTRONIC) wavelength 904 nm, pulsating emission, repeated frequency of the signal from 0 to 5000 Hertz which corresponds at max frequency to an average output power of 19 mW, variable sweep ranging from 2.5 to 2.8 cm/sec. 

The method followed in our Institute to establish the clinical diagnosis of the patient, is the creation of a card in which we register the personal data, clinical diagnosis, medical history, the physiatrist's judgement, the radiologist's report and physicist's opinion. 
We also fill a record card which is specifically prepared for patients suffering from diseases of shoulder, knee and spine in which we indicate: 
1. The intensity of pain, evaluated by means of an analogical visual scale  (Huskisson's scale). 
2. Articular fitness-active and passive, measured in grades and verifed with a goniometer. 
3. The presence of oedema. 
4. The radiologist's report, with particular reference to x-ray standards, ultrasounds, telethermography and, if required, C.T. examination. 
5. The pathogenous noxa. 

Each patient is examined by a team in which a physiatrist, a rheumatologist, an orthopedist, a radiologist and a physicist are present.  
When a laser therapy is prescribed, we elaborate a treatment program (by sweeping method or by points), depending on the clinical diagnosis and patient's  condition.  
In the case of the sweeping method, the area to be treated is outlined with a dermographic pencil on the patient's skin, it includes the area of the articular disease. In the case of treatment by points, the points to be treated are found by means of digital pressure, or by measuring electrical conductive variations of the skin in the acupuncture channels. 
The size of the area to be treated (in “sweeping” method) and the position chosen for the points (in the technique “by points”) are reported on a special anatomical map, used by the technician to complete the treatment in accordance with  the planned scheme. 
For each treatment programme the physicist issues a card in which the irradiation technique and related doses are indicated (Fig. 2). 
At the end of laser therapy, the patients are visited by the same specialist that visited them at the beginning of the treatment, and their clinical record is completed with the physicians and the patient's opinion. 
The results observed are classified by means of a 5 points semiquantative scale (very good, good, fairly good, poor, null), according to an objective functional assessment of the physiatrist and subjective evaluation of the patient. 

Knee osteoarthritis 
Our trial was carried out on 228 elderly people (male and female, mean age 76 years), admitted to the P.A.T.  
Geriatric Institute, suffering from severe osteoarthritis of the knee (II and III radiological stage). 36 patients were treated by CO2 laser, 31 by HeNe laser and 82 by GaAs laser. The sweeping technique was utilized in the case of  CO2 and HeNe laser, while GaAs laser was used either with the sweeping technique (on 65 patients) or by points (on 17 patients).  
In the case of the sweeping method, the area to be treated included the articulation of the knee preferably with 10 x 15 cm range (Fig. 3). 
In the treatment by points, the application was made in correspondance to the lateral and medial condyles of the femur, the articular femur tibia interline, the lateral and medial condyles of the tibia, the peroneal head, the knee cap, the vast median and vast lateral muscles (Fig. 4).  
In particular, in the case of CO2 laser therapy, the treatment was carried out with CO2 apparatus (ETOILE), keeping 1 meter distance between the source and the skin (distribution potency 3.5 Watts), covering an average range of 10x15 cm. The therapy which lasted 10 minutes is carried out 20 times. 
In the case of the sweeping therapy with HeNe, the time of treatment was about 30 minutes, and  the sweep varied from 2.5 to 2.8 cm/sec. 
In the case of GaAs therapy performed by points, the time of application was one minute for point, with a number of points ranging from 10 to 15 for knee, according to the pathology and the anatomical structure of the subject; while if it is performed with the sweeping technique  the time taken was 10'-15'. 
In both cases we tried to vary the conditions of treatment by increasing the frequency of the signal repetition up to a preset average dose of 15 J for treatment. 
Very good - good results were obtained by 67.5% of patients treated by means of CO2 laser, by 72.3% of patients treated with GaAs point technique and 61.3% of the patients treated by means of GaAs sweeping technique and by 42.6% of patients treated with HeNe laser (Table 1). 
No significative statistical difference was noted between the results of CO2 and GaAs treatments (p=0,975), but the statistical analysis showed a significant difference (p=0,02) between the effects of Co2 and HeNe.  
Moreover, we have considerated the effects of different wavelength laser when laser therapy is exclusively applied by means of the sweeping technique. 
The results obtained are presented in Table 2 in which for each type of laser we have indicated the number of patients with very good, good, fairly good, poor or null results. 
Very good - good results were obtained by 61.3% of patients treated with GaAs laser, by 42.6% of patients treated by means of HeNe laser and 67.5% of patients treated with CO2 laser. 

Lumbar Spine Osteoarthritis 
At present we have 117 patients with completely filled cards. They were male and female (mean age 69.3 years) suffering from spine pain due to lumbar osteoarthritis. The treatment was carried out by means of GaAs diode or HeNe laser, by sweeping, by points or combined sweeping-points (Fig. 5, 6, 7) either with GaAs or with HeNe apparatuses.  
The therapy was performed daily (5 treatments/week) mean dose treatment 15 J for the GaAs laser and 4 J for the HeNe laser.  
In the treatment by sweeping, the area included the lumbar spine preferably with a range 10 x 15 cm and in the case of treatmens by points were irradiated the lombar nerves roots.  
Our results are illustrated in Table 3 where, for each type of laser and treatment technique, we have indicated the number of patients with very good, good, fairly good, poor or null results.  
Very good results were obtained by  28 (46%) out of 61 irradiated with GaAs laser by sweeping, while only by 7 (31.8%) out of 22 patients  treated with HeNe by sweeping; 20 (32.7%) patients out of 61 treated with GaAs and 7 (31.8%) out of 22 patients treated with HeNe registered fairly good results. Poor or null effects were obtained in 13 (21.3%) patients out of 61 treated with GaAs but 8 (36.4%) out of 22 treated with HeNe 
(Table 3). 
Moreover we present the results obtained using GaAs Laser by means of the two different techniques (by sweeping or by points) (Table 4). 
12 (44.5 %) patients out of 27 treated with GaAs laser by sweeping and 16 (47%) out of 34 patients treated with  GaAs by points presented very good results; 11 (40.7%) out of 27 treated by sweeping and 9 (26.5%) out of 34 patients treated by points presented fairly good results; 4 (14.8%) patients out of 27 treated by sweeping and 9 (26.5%) out of 34 patients treated by points presented poor or null results. 
The preliminary results controlled by means of statistical evaluation (c2) confirm that GaAs laser has been more effective than HeNe in the treatment of lumbar spine osteoarthritis. 
Reflex sympathetic distrophy syndrome 
At the present we have 140 patients with completely filled cards.   
The treatment was carried out by sweeping on the articulation of shoulder (area 10 x 15 cm) and on the hand (area size 10 x 10 cm) (Fig. 8). Our trial was performed with defocused CO2 at different increasing dose (energy density) in order to obtain the technical conditions which might determine the best effects of treatment. The therapy was performed daily (5 treatment/week) and carried out 20 times.  
In case of evaluation of the objective effects of treament in hemiplegic patients suffering from reflex sympathetic distrophy syndrome, due to the clinical non collaborative conditions of the patients and the presence of different symptoms in shoulder and in hands, which may be singularly or both involved in the disease (with pain and reduced articular fitness in the  shoulder articulation and with oedema on the hand), we classified the effect by means of a semiquantitative scale (presented in a previous work), in which any effect obtained in any single symptom (decreasing of pain, recovery of articular fitness, hand oedema), singularly contributes to the total score of the effect, according to the scale in Table 5. 
Our results are illustrated in Table 5a and 5b where, for each laser type and dose applied, we have indicated the patient number with very good - good, fairly good, poor - null results.  
7 patients (38.9%) obtained very good - good results, 9 patients (50%) fairly good results and 2 patients (11.1%) poor - null results out of 18 patients treated by means of HeNe laser (0.311 J/cm2); but very good - good results were obtained by 5 patient, fairly good results by 4 patients and poor - null results by 1 patient out of 10 treated by means of HeNe lower dose laser (0.229 J/cm2). 
The results obtained in the treatments by means of CO2 laser demonstrated a different distribution in low (137 J/cm2) and high (425 J/cm2) doses, which was confirmed by statistical evaluation. 
Because of different number of patients treated by HeNe or CO2 laser, these results are still preliminary, but a significant statistical difference was observed between the effects of CO2 and HeNe laser (p=0.026). Moreover a significant statistical difference was observed between the effects of high and low CO2 laser doses (p=0.024) and low CO2 laser and high HeNe laser doses (p=0.006). 

Discussion 
First of all, on the basis of the results obtained, we may observe that the different laser apparatuses present a different efficacy when utilized for therapy in some osteoarticular painfull diseases in geriatric patients. 
Infact, we have noted that GaAs lasers may be much more effective than HeNe laser for therapy of osteoarthritis. These results might depend on some physical factors, since 633 nm wavelength laser is less penetrating into the tissue and cannot interact with the target cells below the skin surface. 
About the different result we have obtained with CO2 and HeNe laser beam, we must consider the structural complexity and not homogeneity of the skin: when CO2 and HeNe laser coherent radiations interact with tissue, due to the structural non homogeneity of skin surface, they may produce some speckles that, in the case of CO2 laser light, may induce some local high temperature changes in the tissue. 
This not homogeneous temperature distribution, due to the transmission of hot energy into the skin depth, determines some local areas of increased concentration of biochemical products, which may produce a therapeutic effect. 
Moreover, we must remember that, otherwise it is frequently done, it is not correct to compare the effect obtained applying the same doses of laser radiation produced by different laser source, due to the fact that very different doses of radiation may be re-emitted, as above mentioned about HeNe and CO2 laser beam. 
We may conclude with the ratings of the effect of the therapy on the patients suffering from osteoarticular diseases, and we note that GaAs and CO2 lasers were much more effective than HeNe laser in the treatment of osteoarthritis of spine and of the knee. 
This effect confirms the results obtained by our group in the therapy of elderly patients suffering from lumbago [1,2] and by Suriano [24], on patients suffering from osteoarthritic pain and is also comparable with results of Oshiro and Shirono [23] with regard to lumbago laser therapy on patient at lower mean age. 
The second topic of discussion is the effect of lasertherapy on reflex sympathetic distrophy syndrome.  
While osteoarthritis is a well known degenerative disease of joints, which may occur frequently in elderly people, the patogenous factors (due to peripheral and/or central nervous system) of reflex sympathetic distrophy syndrome are not yet definite and still a topic of discussion. 
Hemiplegic patients, however, may develop reflex sympathetic syndrome and, due to osteoarticular pain, consequently they are not able to undergo rehabilitation from the stroke. 
It is well known that low level laser therapy decreases pain in  joint diseases;  moreover De Luca and Coll [25] noted that defocused CO2 laser might be effective in decreasing osteoarticular pain of shoulder in hemiplegic patients, and Rochkind  demonstrated a stimulator effect of the HeNe low dose laser on injured sciatic nerve in rats, and on the peripheral and central nervous system [20-22]. 
About laser therapy in reflex sympathetic dystrophy syndrome in hemiplegic patients, in our experience, still preliminary, we found that CO2 defocused laser seems to be effective in reducing reflex sympathetic distrophy syndrome in hemiplegic patients (and it is particulary effective in reducing joint pain of shoulder) when low doses are performed. 
This effect might be in line with the results of Von Bruegel et all (1994) on rat Schwann cell proliferation which presented a significant increase at the lowest light intensities. 
In our trial we have tried to determine the laser wavelength which may induce the best therapeutic effect on some different diseases of geriatric patients. 
Next step of our research is now to determine, on the basis of the individual clinical card of each patient, the optimum actually absorbed dose and optimum weekly and total number of treatments to achieve the expected benefit. 
Finally we suggest that laser therapy should be included in the treatment of elderly people suffering from diseases of the spine and of the knee, especially when other concomitant diseases require several prescription of drugs, and in rehabilitative therapy of hemiplegic patients suffering from reflex sympathetic distrophy syndrome. 

Acknowledgement 
This research was supported by C.N.R. (grant n. 93.01564 CT11 and grant n. 9400923 CT11) 

S. Giavelli1, G. Fava1, A. Galanti2,  
E. Hartmann3, L. Pisani4,  
G. Castronuovoo e L. Spinoglio1 

Istituto Geriatrico  
Pio Albergo Trivulzio - Milano.  
Dipartimenti di: Radiologia e Laserterapia1, Reumatologia2, Day Hospital3, Riabilitazione II4  
Ospedale Martini Nuovo, Torino