Mechanisms of shockwave action in the human kidney

Extracorporeal shock wave therapy for sacroiliac joint pain: A prospective, randomized, sham-controlled short-term trial

BACKGROUND

Sacroiliac joint (SIJ) pain can cause lower back pain and pelvic discomfort. However, there is no established standard treatment for SIJ pain. Extracorporeal shock wave therapy (ESWT) is a novel, non-invasive therapeutic modality for musculoskeletal disorders. The mechanism underlying shockwave therapy is not fully understood, but the frequency with which ESWT is applied clinically has increased over the years.

OBJECTIVE

We evaluated the efficacy of using ESWT to treating SIJ pain.

METHODS

Thirty patients with SIJ pain were assigned randomly to ESWT (n = 15) and sham control (n = 15) groups. The ESWT group received 2,000 shockwaves with energy set to the maximum level tolerable by the patient (energy density = 0.09-0.25 mJ/mm2). The probe was oriented perpendicular to the posterior SIJ line, and moved up and down along the joint line. The sham control group received 2,000 shockwaves with the probe oriented parallel to the posterior SIJ line. A 10-cm numeric rating scale (NRS) and the Oswestry Disability Index (ODI) scores were assessed before the intervention, and 1 and 4 weeks post-intervention. Participants were instructed to refrain from using any other conservative treatment, including anti-inflammatory medication and other physical modalities during the study.

RESULTS

In the ESWT group, NRS decreased significantly at post-treatment week 4 (3.64 (95% confidence interval, 2.29-4.99)) compared to baseline (6.42 (5.19-7.66); P < 0.05). ODI improved at 1 and 4 weeks compared to baseline, but not significantly. In the sham group, NRS and ODI did not differ at any post-treatment time point. There was a significant group difference in NRS at week 4 post-treatment (3.64 (2.29-4.99) in the ESWT group vs. 6.18 (5.34-7.02) in the sham control group; P < 0.05), but this was not the case for ODI.

CONCLUSIONS

ESWT represents a potential therapeutic option for decreasing SIJ pain.

Short-term changes in renal function after extracorporeal shock wave lithotripsy in children

PURPOSE

To our knowledge despite numerous studies the biological effect of extracorporeal shock wave lithotripsy (ESWL, Dornier Medical Systems, Inc., Marietta, Georgia) on the function of the immature kidney has not yet been evaluated. We determined the short-term effect of ESWL on renal function in children.

MATERIALS AND METHODS

In a 5-year period 65 children were treated for 77 kidney stones by ESWL and followed regularly at our department. In 16 children the short-term effect of shock wave energy was studied by measuring blood parameters (sodium, potassium, urea, creatinine and C-reactive protein), urinary electrolytes (sodium, potassium and creatinine), urinary enzyme activity (aspartate transaminase, alanine transferase, alkaline phosphatase and lactate dehydrogenase) and the excretion of beta 2-microglobulin. Samples were obtained immediately before and 2 hours after ESWL, and on days 1, 2, 8, 15, 30 and 90 after treatment.

RESULTS

Morphological changes in the kidneys were not detected by ultrasound during followup. No significant changes were noted in overall renal function, serum parameters or urine electrolytes. A significant elevation in the excretion of aspartate transaminase, alkaline phosphatase, lactate dehydrogenase and beta 2-microglobulin was observed, indicating proximal tubular dysfunction and cell destruction. Enzyme levels returned to baseline within 15 days.

CONCLUSIONS

Our results demonstrate that shock wave energy induces transient functional damage of tubular function in children. Minimizing the kV. and number of shocks may decrease the deleterious effect. When considering functional regeneration time, the minimal interval between 2 shock wave treatments should be at least 15 days. The long-term effect needs further investigation.

Side effects of high-energy shockwaves in the human kidney: first experience with model comparing two shockwave sources

The side effects of high-energy shockwaves (HESW) from two different sources on kidney parenchyma obtained from 10 patients treated by radical nephrectomy for renal cell carcinoma were examined. Immediately after nephrectomy, the kidneys were perfused with cold HTK solution and kept in hypothermia (8 degrees C) for a maximum of 4 hours. In five cases, the tumor-free parenchyma was treated at the upper or lower renal pole with 2000 shocks, energy output 21 kV, in an experimental electromagnetic shockwave system (Siemens Co., Erlangen). In the other five cases, the upper or lower poles were treated with 2000 shocks, energy output 24 kV, in an electrohydraulic spark gap system (MFL 5000; Dornier Medizintechnik, Germering). The resulting tissue defects were analyzed by histologic examinations. Changes after treatment with the electromagnetic system were found mainly in the tubules and midsized blood vessels in a well-defined focal area. Treatment with the electrohydraulic system was followed by tubular and glomerular lesions combined with vessel defects in a patchy pattern. The model is able to define the side effects of HESW in the human kidney and to test the side effects of different lithotripters.