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Canine dermatology – historical news:
Clinical observations of an unusual total REGENERATION of a left carpal paw pad of a female Chow-Chow dog. 
By: Erling Pedersen D.C., ESWS.
Case history: Four years prior to the first appointment at the Extracorporeal Shockwave Therapy clinic under Nordic-HealthClinics in Spain, the Chow-Chow had injured her left metacarpal paw pad by stepping on a piece of glass which penetrated deep into the pad. The glass was removed but inflammation and swelling followed. The inflammatory swelling continued and the veterinarian decided to administer multiple punctures in a circle around the pad perimeter to drain the pus, and the pad was bandaged. The dog fought to pull off the bandages and subsequently licked the wound continuously, as this action was not prevented by means of a physical obstruction such as a dog “funnel” around her neck.
The bleeding and oozing of pus from the puncture wounds continued and the dog continued to lick and bite on the pad. In the end the dog managed to chew off the entire paw pad despite many attempts to cause this not to happen. The owners now had to bandage the foot daily and usually had to change bandages twice a day due to oozing of pus and extracellular fluid. Bleeding had subsided to some extent but occasionally the owners observed mild bleeding.  However, the wound did not show signs of healing. The dog kept pulling in the bandages and when she got them off, she would lick the wound profusely.
Over the following three years veterinarians made multiple attempts to control the oozing by various standard medical means, hoping healing of the wound would take place. After many failed attempts, one veterinarian found the best action was to euthanize the dog. Another veterinarian suggested amputating the foot by the joint above and then they would try to cause the new wound to heal by standard methods that had not worked on the pad.  Yet another doctor worked out a plan that included a skin graft even if the outlook at this healing was slim.  The prospective outcome of all well meant suggestions were not encouraging to the owners and they decided against it, and instead they decided to continue to change bandages every day, while hoping for a miracle some day.
In April of 2009 I was consulted by the dog owners in order to attempt to restore the integrity of the blood vascular system in the carpal pad and leg using Extracorporeal Shockwave Therapy.

Anatomy:  The canine paw pad is characterised by thin, pigmentet, keratinised, hairless epidermis covering subcutaneous, collagenous and adipose tissue, which make up the pads. These pads act as a cushion for the load-bearing limbs of the animal. The paw consists of the large, heart-shaped metacarpal pad (forelimb) or metatarsal pad (rear limb), and generally four load bearing digital pads. A carpal pad is also found on the forelimb which is used for additional traction when stopping or descending a slope (particularly in digitigrade species). Additional dew claws can also be present.
 Front paw of dog showing
A) Claw, B) Digital Pads, C) Metacarpal Pad, D) Dew Claw, E) Carpal Pad – The pad that was chewed off in this case.

By examination of the wound and palpation of the muscles of the lower limb, it was noted that
1.the musculature of the mid portion of the limb was hard,
2.the wound was soft to the touch,
3.there was a rim of gray and white pad tissue,
4.the wound was deep red and wet,
5.the exposed musculature had minimal oozing interstitial fluid. 
The objective of the treatment protocol was to use focused shockwaves to:
1.Increase the blood flow to the wound by softening the musculature of the lower limb proximal to the wound, 
2.Stimulate the “progenitor cells” *) of the dark and white portions of the rim of the pad, and 
3.Open the capillary vessels of the exposed muscle fibers.
4.Stimulate the release of growth factors like VEGF, TGF and anti-inflamatory effect due to nitric oxide (NO).
The theory behind the planned protocol was:
1) To eliminate any restriction to the arterial blood flow feeding the pad and venous return caused by a chronic spasm of the muscle fibers and muscle bundles of the lower limb. This would resemble the treatment protocol we normally follow in humans.
2) To stimulate the Progenitor Cells *) of the visible gray and white pad tissue would cause these cells to proliferate and at least a healing of the edges of the wound would occur.
3) To open the capillary vessels of the muscle fibers would result in a better blood flow and possibly neovascularization to occur. This would make it possible for the natural cleaning and feeding of nutrients to the wound to occur.  
Physical treatment:
The Storz Duolith SD 1 shockwave unit was used with the F-SW head and the long stand-off(1,5cm focal depth).
1st treatment, March 1st 2009: The wound was covered with sterile ultrasound gel on top of which a layer of transparent polymer plastic was placed. On top of the plastic a generous amount of regular ultrasound gel was deposited.
Procedure: The sound head was used at an angle of 60° with ample gel in front of the sound head to accommodate complete connection through the gel of the acoustical wave so that no air pockets between the sound head and the wound surface.  The angle of wave entry and penetration was precise to ensure the lengthwise and crosswise directions into the muscle fibers, and they would also hit the blood vessels in lengthwise and crossed directions. This application method is essential for proper blood flow through the structures.  We never pointed the waves directly on to the periosteum, but we use the flat angles to gently bounce the waves off the bones, causing no discomfort, and a maximum utilization of the energies administered.  
The perimeter of the wound was exposed to the waves from the center of the wound towards the perimeter, gradually hitting all the tissue as the treatment head was moved approximately 2 mm per shot. The settings were 0.20mJ/mm² at 2.5Hz with a total energy of 2 Joules (approximately 300 pulses) deposited.
Then generous amounts of gel was used on the posterior side of the lower limb proximal to the wound using a setting of the sound head at 0.20mJ/mm² at 2.5Hz with a total energy of 2 Joules (approximately 300 pulses) deposited in the tissues.
2nd treatment March 15th 2009: The wound had started to mildly bleed shortly after the first treatment which had not been seen for more than a year.  The bleeding continued for about 2 days after which it subsided and the color of the wound had changed to a lighter read color. There were two or three spots of about 3mm² where we saw slight bleeding. The muscles of the lower limb palpated soft much like the right lower leg. 
The same procedures as for the first treatment preparing and protecting the wound for the treatment as well as the angel of the treatment head during the application were followed. Additionally the middle of the wound was treated so that the entire surface and perimeter was treated. 0.20mJ/mm² at 2.5Hz with a total energy of 2.64 Joules (approximately 400 pulses) was deposited.  The lower leg was not treated during the procedure.
3rd treatment April 18th, 2009: The wound had not bled, the oozing had subsided, but the texture of the wound was still moist and had changed to a pink healthy color.  Additionally it was noted that new pad tissue was growing from the one side
The same procedures as for the first treatment preparing and protecting the wound for the treatment as well as the angel of the sound head during the application were followed. Additionally the middle of the wound was treated so that the entire surface and perimeter was treated. 0.20mJ/mm² at 2.5Hz with a total energy of 2.64 Joules (approximately 400 pulses) was deposited.

4th treatment Maj 3rd, 2009: The pad tissue keeps growing, especially at the edge where growth was first seen. Now about 50% of the wound had healed over with the characteristic pad tissue.  The same procedures as the previous treatments preparing and protecting the wound for the treatment as well as the angel of the treatment head during the application were followed. Now focus was on the growing pad tissue as the open wound was still healing with patches of white cells. We have interpreted these cells to be mature, growing pad cells patches. No histological samples were taken as we did not have the proper equipment necessary to secure and protect such samples.    0.25mJ/mm² at 2Hz with a total energy of 3.27 Joules was deposited.
5th treatment June 8th, 2009: The pad has grown to cover about 70% of the original wound as shown below.

The pad tissue was soft and felt like that of a puppy’s.  The edge of the healing pad showed clearly the white tissue that seemed to have been the precursor to the formation of the full body of the pad including the dark outer “epidermis”.     Treatment focus was again on the perimeter of the growing pad tissue and on the few remaining patches of white cells conglomerates in the middle of the red moist part of the wound. The settings and energy used were: 0.25mJ/mm² at 2Hz with a total energy of 3.27 Joules deposited. 0.30mJ/mm² at 2Hz with a total energy of 1.51 Joules was deposited.
6th treatment June 14th, 2009:  The wound was now closed and protected against bacterial and other contamination. The “fleshy” red and previously bleeding, open portion of the wound was now replaced in part by crusty scar tissue and in part by pink solid tissue – not pad like tissue. The dog could now walk without a limp and was not interested in licking the (former) wound at all.
We decided to treat the crusty edge lightly and used the same basic procedure as previously used and the settings and energy used were: 0.30mJ/mm² at 2Hz with a total energy of 1.383 Joules was deposited.
No further treatment was considered necessary and by June 24th, 2009 the entire pad was complete and getting harder to the touch and appeared like the pad on the right leg.

Final result prior to the scab fell off.
From the very start of this treatment sequence, the dog cooperated fully during the procedure.  It was feared that it would have been necessary to have restraints and mouth guard on the dog judging from how the dog responded to the veterinarian doctors.  After all, the dog would most likely view me as yet another doctor who would inflict pain. However, the dog was calm and only occasionally reacted slightly to the shockwaves - most likely, when I hit heraperiosteum in too straight of an angle. She was at ease with the treatments and was very eager to get into the clinic, pulling her owner along as she was heading in through the door.
These facts are interesting and may imply that shock waves when induced with care, precision and purpose have an added beneficial effect in the body, that caused the dog to actually enjoy the sessions, and wanting more. Why did she accept me and our treatment so easily? Whatever the inner psychological mechanism may be, I will abstain from speculating on, and leave that to experts in this field to ponder over.
The reformation of the pad was a major step for ESWT science and warrants further studies into the effect of shock waves on Progenitor cells. Scientific work has already been done in the field as indicated below.
The healing of non-healing wounds using shockwaves is not new. Many types of wounds have been treated successfully by shockwaves which prompts due consideration by all hospitals to have the technology available in order effectuate healing.  Conventional medical treatment protocols have proven inadequate and new measures must be urgently considered.   Proper scientific trials must be conducted on the variety of non-healing wounds that do not respond to standard medical.
We here invite to a discussion forum. 
Erling Pedersen D.C. ESWS.
Contact information ep@nordic-healthclinics.com

*) Progenitor cells:
Volume 33, Issue 11, Pages 1371-1387 (November 2005)
Feasibility of cord blood stem cell manipulation with high-energy shock waves: An in vitro and in vivo study
Massimo Bergera, Roberto Frairiab, Wanda Piacibelloc, Fiorella Sanaviob, Alessandra Palmeroa, Claudio Venturia, Ymera Pignochinoc, Laura Bertab, Enrico Madona, Massimo Agliettac, Franca Fagiolia
Received 16 December 2004; received in revised form 6 July 2005; accepted 8 August 2005
Objective:  The aim of this study was to evaluate whether pretreatment with high-energy shock waves (HESW) could further enhance the expansion of cord blood progenitors and the transduction efficiency with lentiviral vectors.
Conclusion:  The pretreatment of CD34+ cells with HESW represents a new method to manipulate the CD34+ population without interfering with their ability to both expand and engraft and it might be considered as a tool for genetic approaches.
The surface of articular cartilage contains a progenitor cell population
Gary P. Dowthwaite, Joanna C. Bishop, Samantha N. Redman, Ilyas M. Khan, Paul Rooney, Darrell J.R. Evans, Laura Haughton, Zubeyde Bayram, Sam Boyer, Brian Thomson, Michael S. Wolfe, and Charles W. Archer*
* Author for correspondence (e-mail: archer@cardiff.ac.uk)
It is becoming increasingly apparent that articular cartilage growth is achieved by apposition from the articular surface. For such a mechanism to occur, a population of stem/progenitor cells must reside within the articular cartilage to provide transit amplifying progeny for growth.
•  Andrea S. Bischofberger, Simone K. Ringer, Hans Geyer, Isabel Imboden, Gottlieb Ueltschi, Christoph J. Lischer. (2006) Histomorphologic evaluation of extracorporeal shock wave therapy of the fourth metatarsal bone and the origin of the suspensory ligament in horses without lameness. American Journal of Veterinary Research 67:4, 577
•  Scott R. McClure, Iona M. Sonea, Richard B. Evans, Michael J. Yaeger. (2005) Evaluation of analgesia resulting from extracorporeal shock wave therapy and radial pressure wave therapy in the limbs of horses and sheep. American Journal of Veterinary Research 66:10, 1702
•  Simone K. Ringer, Christoph J. Lischer, Gottlieb Ueltschi. (2005) Assessment of scintigraphic and thermographic changes after focused extracorporeal shock wave therapy on the origin of the suspensory ligament and the fourth metatarsal bone in horses without lameness. American Journal of Veterinary Research 66:10, 1836