Prosthetic Fit and Comfort Depends on the Shape of the Socket
Hand-casting has long been the standard for acquiring an accurate mold of an amputee’s residual limb. While hand-casting can provide a fairly accurate mold and is still a useful technique and option to utilize, there are constantly new technologies and advances in this field that are greatly benefiting the patient and improving the process. The Symphonie Aqua casting system tank utilizes hydrostatic pressure in a cylinder around the patient’s residual limb to capture an accurate impression of their connective tissue and bony structures. The patient is able to fully weight bear onto their affected side while in the tank, which simulates what the shape of their limb will be in the socket when they are standing or walking in the prosthesis. The water bladder in the tank flows around the limb providing even pressure and contact throughout the whole casting process, proving a more accurate impression of their limb. There is a tank for both above knee and below knee amputees. It is a great tool to utilize for a better and more comfortable fitting socket. When used properly, not only does this system provide a more accurate and comfortable socket for the patient, it also saves time for both the patient and practitioner due to a more efficient and effective process.
Are there proven benefits compared to hand-casting?
A study was done on seven transtibial amputee patients in varying states of physical condition. Each of the patients had three impressions of their limb taken: manual (hand), optical scan, and hydrostatic using the Symphonie Aqua System. The researchers compared volume of the casts, stand up and walk test, and walk and distance tests between the subjects in each impression. The patients were not told which socket came from which impression technique during the study. The results of the study revealed, “the comparison of volume showed that the hydrostatically produced sockets had a larger volume than those produced by both the manual impression method and the optical scanning method....However, despite the larger volume, it was further ascertained that the hydrostatically produced sockets did not necessitate the use of residual limb socks for compensation purposes and the fit and adhesion were exactly reproduced” (Denune, 2019). In the stand up and walk test, the results showed significantly less time was needed for the hydrostatic socket, compared to the sockets produced by the other methods. In the walk and distance test, it was revealed that the subjects using the hydrostatic socket were able to walk significantly longer distance in two minutes compared to the other sockets. While this study includes a smaller sample size, it shows promising results with the positive experience fitting sockets from the Symphonie Tank and opens the door for larger studies to be completed in the future.
Casting Appointment Process
If you are scheduled for a casting appointment for a prosthesis, the practitioner will first determine if you are an appropriate candidate for utilizing the Symphonie Aqua System tank. To use the tank system for casting, the patient must have adequate balance and strength in the contralateral limb because they will be required to stand for a few minutes while the plaster cast solidifies. They also must be fully healed and be able to withstand compression around their limb. If the practitioner decides to move forward utilizing the Symphonie tank, the patient will be prepped in the casting room, fit with a liner, and wrapped with cellophane to keep the skin and liner clean. The practitioner will then wrap the limb with plaster bandage. Once the limb is wrapped, the patient will put their limb in the Symphonie tank and it will be filled with water until the bladder in the tank completely fills with water and compresses the plaster bandage around the residual limb. The patient will be held under compression for around 3-5 minutes or until the plaster has hardened. The tank will then be drained, and the patient will be able to pull their limb out of the tank and remain seated for the rest of the process.
If you are an amputee struggling with socket discomfort or are interested in learning more about this casting technique, contact Tillges Orthotics and Prosthetics today and schedule a complimentary consultation.
- Denune, J. (2019). Comparative Observational Study – Blind Test Hydrostatic Casting vs. Other Residual Limb Impression Methods. Motus Research LLC, 1-5.