Volume 134, Number 2 • Letters Reply: Use of Polyglycolic Acid Nerve Conduit (Neurotube) to Alleviate Pedicle Kinking in Microvascular Anastomosis Sir:
We appreciate the opportunity to comment on the recent letter by Dr. Sapountzis and colleagues, wherein the authors described a novel technique of preventing kinking in a free flap pedicle by affixing a 4-0 polydioxanone (Ethicon, Inc., Somerville, N.J.) suture to the adventitia of the anastomotic segment using a 9-0 nylon suture. This is an elegant, low-cost solution to pedicle kinking that is effective according to the authors’ series of 11 patients treated with this technique. This adds at least a small degree of technical difficulty and a possible risk of injury to the endothelium, either by suture trauma or increased manipulation of the vessels, which could potentially cause thrombus formation. In addition, the use of polydioxanone suture material as an external “rod” exploits the intrinsic memory of the suture, yet the ex vivo memory may not be generalizable in vivo, because heat, moisture, and mechanical forces will lessen its memory. We recently described a simple technique using a polyglycolic acid nerve conduit (Neurotube; Synovis, Birmingham, Ala.) for the same indication. We split the Neurotube longitudinally and ensheathed the anastomotic segment within the tube with minimal added manipulation of the pedicle. Although compression of the vascular pedicle is theoretically a risk of using this device, we did not appreciate any compression intraoperatively, nor were flap-related complications noted postoperatively. The Neurotube is available in different diameters that can accommodate larger or smaller vessel diameters to address this concern. Increased cost of the device is a legitimate drawback of this technique, but for the right patients, this technique will provide added mechanical support of the pedicle, with minimal clinical risks. Both approaches appear to be viable options for a commonly encountered yet incompletely studied problem. DOI: 10.1097/PRS.0000000000000389
Michael A. Holliday, M.D. MedStar Georgetown University Hospital Washington, D.C.
Steven P. Davison, M.D., D.D.S. DAVinci Plastic Surgery Washington, D.C. Correspondence to Dr. Davison DAVinci Plastic Surgery 3301 New Mexico Avenue, NW #236 Washington, D.C. 20016 [email protected]
DISCLOSURE The authors have no financial interest in any of the products or devices mentioned in this communication.
Nanofat Grafting: Basic Research and Clinical Applications Sir: t was interesting to read the article titled “Nanofat Grafting: Basic Research and Clinical Applications.”1 Clinical application of fat grafting has changed over the years from autologous fat aspirate to adiposederived stem cell therapy. The authors have developed a simple technique of clinically useful adipose-derived stem cell concentrate without the need for complex isolation procedures. This will not only overcome the difficulty in injecting the fat with a fine needle, but also reduces the technical and ethical issues involved with the use of adipose-derived stem cells. However, the scientific validity of the terminology “nanofat grafting” is questionable. We feel “supermicrofat grafting” will be a better term for this innovative technique. Autologous fat grafting has become the standard technique for filling soft-tissue defects using the Coleman technique.2 In this technique, fat is harvested with a 3-mmdiameter cannula with a 2-mm side hole and injected with large cannulas. This macrofat does not allow subdermal injection using small cannulas. Trepsat3 described the microfat graft technique in which fat was harvested with a 2-mm-diameter cannula with 1-mm side holes. Nguyen et al.4 used the microfat technique by multiperforated cannula with 600-μm-diameter holes and injected with a 25-gauge cannula (inner diameter, 260 μm). This facilitated very superficial and subdermal injection of fat. Tonnard et al.1 mechanically emulsified fat and filtered it with a sterile nylon cloth with a 500-μm pore size. The effluent collected is called “ nanofat” and injected with a 27-gauge needle (inner diameter, 210 μm). They have used 70-μm filters for isolation of stem cells (size range, 10 to 15 μm) during cell culture. Because the so-called nanofat is in fact in the micrometer range, we propose the term supermicrofat grafting for this technique to differentiate it from the microfat grafting technique and to avoid confusing it with nanotechnology. We feel the scientific terms should be precise and without any ambiguity. A nanometer is one billionth of a meter. Use of materials at the nanoscale has led to expansion of nanotechnology in various scientific fields, including medicine. There are many diverse perspectives on nanotechnology, which necessitated a common definition for nanoscale. The U.S. government defines nanotechnology as science, engineering, and technology conducted at the nanoscale, which is approximately 1 to 100 nm.5 With this definition, we cannot even include isolated stem cells in the nanoscale. We hope the terminology of supermicrofat will reduce the confusion of equating emulsified fat aspirate to nanotechnology.
I
DOI: 10.1097/PRS.0000000000000333
M. T. Friji, M.S., M.Ch. Department of Plastic Surgery Jawaharlal Institute of Postgraduate Medical Education and Research Pondicherry 605006, India [email protected]
333e
We appreciate the opportunity to comment on the recent letter by Dr. Sapountzis and colleagues, wherein the authors described a novel technique of preventing kinking in a free flap pedicle by affixing a 4-0 polydioxanone (Ethicon, Inc., Somerville, N.J.) suture to the adventitia of the anastomotic segment using a 9-0 nylon suture. This is an elegant, low-cost solution to pedicle kinking that is effective according to the authors’ series of 11 patients treated with this technique. This adds at least a small degree of technical difficulty and a possible risk of injury to the endothelium, either by suture trauma or increased manipulation of the vessels, which could potentially cause thrombus formation. In addition, the use of polydioxanone suture material as an external “rod” exploits the intrinsic memory of the suture, yet the ex vivo memory may not be generalizable in vivo, because heat, moisture, and mechanical forces will lessen its memory. We recently described a simple technique using a polyglycolic acid nerve conduit (Neurotube; Synovis, Birmingham, Ala.) for the same indication. We split the Neurotube longitudinally and ensheathed the anastomotic segment within the tube with minimal added manipulation of the pedicle. Although compression of the vascular pedicle is theoretically a risk of using this device, we did not appreciate any compression intraoperatively, nor were flap-related complications noted postoperatively. The Neurotube is available in different diameters that can accommodate larger or smaller vessel diameters to address this concern. Increased cost of the device is a legitimate drawback of this technique, but for the right patients, this technique will provide added mechanical support of the pedicle, with minimal clinical risks. Both approaches appear to be viable options for a commonly encountered yet incompletely studied problem. DOI: 10.1097/PRS.0000000000000389
Michael A. Holliday, M.D. MedStar Georgetown University Hospital Washington, D.C.
Steven P. Davison, M.D., D.D.S. DAVinci Plastic Surgery Washington, D.C. Correspondence to Dr. Davison DAVinci Plastic Surgery 3301 New Mexico Avenue, NW #236 Washington, D.C. 20016 [email protected]
DISCLOSURE The authors have no financial interest in any of the products or devices mentioned in this communication.
Nanofat Grafting: Basic Research and Clinical Applications Sir: t was interesting to read the article titled “Nanofat Grafting: Basic Research and Clinical Applications.”1 Clinical application of fat grafting has changed over the years from autologous fat aspirate to adiposederived stem cell therapy. The authors have developed a simple technique of clinically useful adipose-derived stem cell concentrate without the need for complex isolation procedures. This will not only overcome the difficulty in injecting the fat with a fine needle, but also reduces the technical and ethical issues involved with the use of adipose-derived stem cells. However, the scientific validity of the terminology “nanofat grafting” is questionable. We feel “supermicrofat grafting” will be a better term for this innovative technique. Autologous fat grafting has become the standard technique for filling soft-tissue defects using the Coleman technique.2 In this technique, fat is harvested with a 3-mmdiameter cannula with a 2-mm side hole and injected with large cannulas. This macrofat does not allow subdermal injection using small cannulas. Trepsat3 described the microfat graft technique in which fat was harvested with a 2-mm-diameter cannula with 1-mm side holes. Nguyen et al.4 used the microfat technique by multiperforated cannula with 600-μm-diameter holes and injected with a 25-gauge cannula (inner diameter, 260 μm). This facilitated very superficial and subdermal injection of fat. Tonnard et al.1 mechanically emulsified fat and filtered it with a sterile nylon cloth with a 500-μm pore size. The effluent collected is called “ nanofat” and injected with a 27-gauge needle (inner diameter, 210 μm). They have used 70-μm filters for isolation of stem cells (size range, 10 to 15 μm) during cell culture. Because the so-called nanofat is in fact in the micrometer range, we propose the term supermicrofat grafting for this technique to differentiate it from the microfat grafting technique and to avoid confusing it with nanotechnology. We feel the scientific terms should be precise and without any ambiguity. A nanometer is one billionth of a meter. Use of materials at the nanoscale has led to expansion of nanotechnology in various scientific fields, including medicine. There are many diverse perspectives on nanotechnology, which necessitated a common definition for nanoscale. The U.S. government defines nanotechnology as science, engineering, and technology conducted at the nanoscale, which is approximately 1 to 100 nm.5 With this definition, we cannot even include isolated stem cells in the nanoscale. We hope the terminology of supermicrofat will reduce the confusion of equating emulsified fat aspirate to nanotechnology.
I
DOI: 10.1097/PRS.0000000000000333
M. T. Friji, M.S., M.Ch. Department of Plastic Surgery Jawaharlal Institute of Postgraduate Medical Education and Research Pondicherry 605006, India [email protected]
333e
