Postmastectomy lymphoedema. Treatment and a five-year follow-up study.

BACKGROUND: Lymphoedema of the arm is a common problem after mastectomy and radiotherapy of mammary cancer. In a prospective 5-year follow-up study we investigated the development of arm oedema and the effect of conservative compression treatment. METHODS: Two hundred and twenty-six patients who had undergone mastectomy were investigated. Oedema formation was estimated by recording displaced water volume of both arms preoperatively and six times post-operatively. One hundred fifty-seven patients (70%) could be followed for five years. An inter-arm difference of 100 ml or more was defined as oedema. Three types of treatment were given: (1) Compression with stockings in 28 patients, (2) intermittent compression (Flowtron) in 8 and (3) intermittent compression (Lympha-Press) and compression sleeves in 19 patients. RESULTS: A total of 46 patients (20%) developed post-operative oedema, 17 within six months and 29 one year postoperatively. The average oedema volume was 418 ml. Most patients with a moderate or severe oedema had irradiation therapy. Severe lymphoedema (750 ml or more) occurred in patients with irradiation postoperatively and lymph node engagement. There was no correlation between patient age and oedema formation. Compression therapy with stockings reduced oedema in 15 out of 28 patients (54%) and prevented further swelling. Therapy with stockings and Lympha Press reduced the arm volume in 13 out of 19 patients (68%). Four out of eight patients treated with Flowtron showed oedema reduction. In most patients cessation of treatment resulted in relapse of swelling to the same degree as before. CONCLUSIONS: Compression therapy is beneficial to control postmastectomy arm swelling. This applies to different modalities and prolonged periods of treatment are required to check progression. Application of stockings is the simplest way to treat postoperative oedema. In most cases postoperative oedema appeared during the first year after surgery and the most severe cases occurred after irradiation.

Dynamics of transcapillary fluid transfer and plasma volume during lower body negative pressure.

Lower body negative pressure (LBNP) is a stimulus frequently used to study reflex circulatory responses in humans. Studies have provided data on LBNP-induced blood pooling; however, the possibility that LBNP also might be associated with an important loss of plasma fluid has attracted little attention. Therefore this problem was analysed in male volunteers exposed to prolonged (10 min) high (70-75 mmHg) LBNP. Data on LBNP-induced blood pooling that were more reliable than in previous literature were also provided. LBNP caused early pooling of more than 870 ml of blood. Rapid filtration of plasma into the exposed tissues occurred throughout LBNP. The cumulative oedema in the legs and buttocks averaged as much as 460 ml, and additional quite large volumes of plasma apparently accumulated in other parts of the lower body. Concomitantly, there was compensatory absorption of extravascular fluid in the upper body. The net decrease in plasma volume (PV) was still large and averaged 491 +/- 29(SE) ml. Two aspects of the demonstrated process of transcapillary fluid fluxes and PV decline may be emphasized. Firstly, in conjunction with the primary large redistribution of intravascular volume, it certainly implies that LBNP is a potent stimulus as also indicated by a progressive increase in heart rate (HR) and a progressive decline in systolic pressure throughout experimental intervention. In fact, LBNP-induced circulatory stress clearly has bearings on the extreme hypovolaemic situation provided by the pressure-bottle haemorrhage technique used in animals. Secondly, it not only offers an interesting example of the dynamics of PV but appears to have more general validity with regard to states characterized by gravitational shifts of blood (hydrostatic load), like upright exercise and quiet standing.

Short-term synchronization of motor units in human extensor digitorum communis muscle: relation to contractile properties and voluntary control.

Synchronous activity was studied in relation to the contractile properties of pairs of motor units (MUs) recorded with independent microelectrodes in the right extensor digitorum communis muscle (EDC) of human subjects during isometric finger extension. MU contractile properties were characterized in terms of the rise time and amplitude of twitch tensions extracted by spike-triggered averages of the extension force. Synchronization of MU discharges appeared in the form of narrow central peaks in the cross-correlograms of 35 of 50 pairs of MUs, suggesting the contribution of common last-order neurons. Synchronization peaks tended to be briefer and higher among pairs of MUs with slower and smaller twitches than among pairs of MUs with faster and larger twitches. The higher peaks of slow-contracting MUs suggest a greater effectiveness of the common synaptic inputs. The broader peaks of fast-contracting MUs might reflect an additional synchronization of the inputs to fast MUs at high force levels. The areas of the cross-correlogram peaks were similar for both groups and suggest that under our conditions, about three motoneurons would discharge synchronously for a given motoneuron spike. To test whether the amount of MU synchronization could be altered voluntarily, four subjects attempted to increase or decrease synchrony, using as feedback clicks triggered by coincident firings of the recorded MUs. In nine of 15 conditioning sessions, the magnitudes of the synchronization peaks showed significant changes in the intended direction. These results imply that supraspinal centers can control the relative amount of inputs that contribute to the synchronization of motoneuron discharges during voluntary contraction of EDC.

Influence of auditory localization cues on neuronal activity in the auditory thalamus of the cat.

1. The response properties of auditory thalamic neurons to the two major localization cues characterizing the azimuth of sound sources in the horizontal plane were investigated in cats. Single-unit responses to auditory stimuli (white noise and tones) presented with interaural phase differences (IPD) or interaural intensity differences (IID) were studied. 2. The proportion of neurons in the medial geniculate body that were sensitive to the localization cues tested was 28% for IPD (n = 253) and 37% for IID (n = 65). Half of the IID-sensitive units were also sensitive to IPD, but when the range of IPDs and IIDs to which each unit responded was converted to the sound-source locations that would generate those ranges they did not always correspond to overlapping azimuth angles. 3. The changes in discharge rate in response to the two localization cues occurred over very broad IPD and IID ranges. If this activity is involved in the representation of acoustic space, then the responses of individual neurons do not provide fine spatial tuning. 4. Contralateral and ipsilateral ear leads were represented in a continuous manner by the maximum discharge rate of IPD-sensitive units. On the other hand, units that were sensitive to IIDs were activated over one of two delimited ranges of IIDs. The first corresponded to IID combinations in which the stimulus was presented at a higher intensity in one ear than in the other (for 15/17 units the contralateral one); these were the lateralized intensity response field units. The second are the centered intensity response field units, whose responses were maximal when the intensity was equal in both ears and decreased when IIDs were introduced.

Functional ear asymmetry in vertical localization.

Vertical frontal mid-saggital plane localization was tested in binaural, monaural left and monaural right ear conditions. Band-pass noise stimuli were presented pseudorandomly through one of four loudspeakers set with an angular separation of 11 degrees. The subject's performance, based on reaction time and mistakes, was continuously recorded. The binaural performance was twice as high as the monaural performance, suggesting that the two ears treat the information in a different and complementary way. The left ear performance was higher than the right ear performance; this strongly suggests a right hemisphere superiority for vertical localization.