Fat Graft Size: Relationship Between Cannula and Needle Diameters

Abstract

BackgroundIt is generally believed that trauma to fat grafts is detrimental and affects the survival of the graft. In addition, it has been shown that smaller fat particle size corresponds to better survival; however, smaller cannula openings correspond to slower and more difficult fat graft harvesting. ObjectivesThis study documents the relationship between cannula size, harvested fat cell size, and injection needle size. A means of reducing fat particle size following aspiration with larger diameter cannulas is also discussed. MethodsFat was harvested from five patients undergoing elective liposuction. Each fat sample was placed in a syringe and injected through progressively smaller needles until obstruction under low pressure was obtained. The minimal needle size was documented for each sample. ResultsFat harvested with a liposuction cannula results in different size fat particles ranging up to the size of the cannula. Particles obtained from 3-and 4-mm cannulas can be injected without obstruction through a 16-gauge needle. Particles obtained from a 2-mm cannula can be injected without obstruction through an 18-gauge needle. Particles obtained from a 1-mm cannula can be injected without obstruction through a 20-gauge needle. Particles obtained from a 1-mm cannula could not be injected without obstruction through a 22-gauge needle. ConclusionsThere is a relationship between cannula opening size and the resultant fat graft size. Fat particles are somewhat compressible but should not be forced through needles or cannulas that are too narrow. It may be beneficial to harvest fat with larger cannulas and cut the particles to smaller sizes for injection.

Alopecia Areata Treated with Advanced Platelet-rich Fibrin Using Micronization

“… 17 Through micronization, it is possible to convert the aPRF clot into a particle size injectable through a smaller gauge needle, similar to fat grafting. 18 This allows for the quick preparation of the solutions for injection using the patient’s blood without anticoagulants, the added benefits of increased growth factors, and the flexibility of injecting with smaller needles as the PRF matrix is too thick for standard injection needles compared with PRP. Although alopecia areata is self-resolving in 50% of cases within a year, typical treatment consists of monthly injections with intralesional steroids due to its recurrence, and our patient had similar results with two treatments almost 2 months apart.…”

Nanofat: A therapeutic paradigm in regenerative medicine

“…However, there is a lack of consensus among studies on the ideal size to be utilized. While the conventional recommendation is to use a cannula less than 2.5 mm diameter to enhance the vitality of fat graft, but Erdim et al [ 59 ] did not note similar findings in their study on cell viability with differing needle gauge sizes[ 57 - 60 ].…”

Long-Term Clinical and Aesthetic Results of a Systematic Fat Transfer Protocol for Total Breast Reconstruction after Nipple-Sparing Mastectomy

“…9,25 The cannulas we use are considered closest in diameter to 16-gauge needles (1.19 mm) and sufficient for harvesting larger fat particles used for breast reconstruction. 27 We find that injecting smaller volumes of adipose tissues ("microfractions," as described by Coleman) through 1-mm cannulas creates microchannels that might facilitate engraftment of adipose tissue in the recipient site. This maximizes surface area contact between adipocytes and surrounding tissues.…”