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The use of SNAP home therapy in a young patient with diabetic foot ulcer to expedite return to function

Author(s): Jolie Hwee, Joseph Lo

Published: 26 November, 2021

Case Study


Mr N is a 45 year old Chinese gentleman with a medical history of diabetes mellitus, hypertension, hyperlipidemia, peripheral artery disease, and is an ex-smoker. He developed an infected ulcer over his right 4th toe and underwent right lower limb angioplasty followed by 4th toe ray amputation on 21/12/18. The wound measured 3.2 (length) x 1.3 (width) x 2.0cm (depth) with exposed bone. The 3MTM SNAPTM therapy system was chosen for its slim trackpad design that can fit between the toes – in contrast, the conventional V.A.C system will require a bridging foam landing zone to accommodate for the broader trackpad. As our patient was young and independent, comfort and the ability to resume his daily activities were important to him – these factors were taken into consideration when choosing the SNAPTM therapy system for its ultra-portable, lightweight and quiet design that can be easily hidden under clothes.



The patient was initiated on SNAPTM therapy system inpatient immediately after the ray amputation. PROMOGRAN PRISMATM Matrix was laid on the wound bed, and the wound edges were lined with hydrocolloid paste before applying the SNAPTM therapy system at -125mmHg continuous negative pressure. The device was strapped onto the patient’s leg and hidden under his clothing. The patient was subsequently discharged with home SNAPTM therapy. Wound outcomes and images of the wound were recorded at each follow-up visit by the wound nurse (twice a week).



The patient’s hospitalization stay was 9 days. After 6 weeks of SNAPTM therapy, there was 50% reduction of wound size with complete obliteration of wound cavity, and 100% granulation tissue over the wound base with no slough. There no complications of skin maceration, wound infection or need for further debridement. The patient was then converted to conventional silver dressings every other day. The wound healed completely 3 weeks later. At 7 months follow-up, there was no adverse effects of osteomyelitis, recurrence of ulcer or further amputations required.

Figure 1: Fourth ray amputation wound measuring 3.2 (length) x 1.3 (width) x 2.0cm (depth) with exposed bone. Patient was commenced on 3M SNAP therapy system immediately post operation.


Figure 2: PROMOGRAN PRISMA Matrix was laid on the wound bed, and the wound edges were lined with hydrocolloid paste before applying the SNAP therapy system at -125mmHg continuous negative pressure.


Figure 3: The slim trackpad design of the SNAP therapy system allows for easy application of the dressing between the toes. The cartridge is strapped on the patient’s leg, which can be easily hidden under clothing.


Figure 4: After 6 weeks of SNAP home therapy, the wound was reduced by 50% with obliteration of the wound cavity.


Figure 5: Complete healing of the 4th ray amputation wound after 6 weeks of SNAP home therapy and 3 weeks of silver dressings.



Diabetic foot ulcers are a growing problem which is estimated to affect 15% of the population in Singapore by 2050 [1]. Wound healing is challenging as they are often associated with the triad of peripheral vascular disease, neuropathy and infection, which often results in chronic, recurring wounds or amputation [2]. Diabetic foot ulcers are especially debilitating for ambulant patients who value their ability to resume their daily activities, social interactions and comfort. The use of negative pressure therapy has changed the paradigm of wound healing through its mechanism of macro- and micro-deformation, which promotes granulation tissue, and removes excess fluid from open wound. We combine the use of negative pressure therapy with PROMOGRAN PRISMATM Matrix, which has been shown to expedite granulation, especially over exposed critical structures like bone in this case.


Conventional negative pressure therapy are often bulky, noisy and inconvenient to carry around. The introduction of SNAPTM therapy system combines the benefits of the negative pressure therapy system with added features of a silent, lightweight, ultra-portable design that allows unrestricted mobility while treating wounds, and furthermore avoids social stigma by easily concealing the devices under clothing. The SNAPTM therapy system enables wounds to be recuperate in an outpatient setting, and this results in reduced hospital length of stay, which confers healthcare savings, frees up healthcare resources, while achieving greater patient satisfaction. Our pilot prospective study has shown estimated cost savings of $300 per person compared to electrical negative pressure wound therapy – this may be due to savings from device rental, shorter duration of therapy needed or reduced number of device changes [2]. These single-use devices are ideal for small wounds which are minimally exudate, and are easy to carry around for ambulant patients like Mr N. The SNAPTM therapy system is easy to apply in less than 10 minutes; its slim trackpad allows easy application in narrow wounds; and the system that can be easily troubleshoot by patients.



The use of mechanical NPWT in the home setting has increased patient satisfaction rates as they are able to recuperate at home and resume daily activities during the duration of therapy. SNAPTM therapy system is convenient, and has demonstrated excellent wound healing rates, with no additional complications.