John E. Hoopman

Effect of low-level laser therapy on abdominal adipocytes before lipoplasty procedures.

Low-level laser therapy is a new subspecialty for the medical application of lasers that provides therapeutic rather than surgical outcomes for many medical indications. Recently, low-level laser therapy was reported to “liquefy” or release stored fat in adipocytes by the opening of specialized yet not identified cell membrane–associated pores after a brief treatment. Currently, low-level laser therapy is a U.S. Food and Drug Administration–approved technology for improving pain alleviation. To explore these data further, a series of in vitro studies on human preadipocytes and institutional animal care and use committee–approved protocols in a porcine Yucatan model and an institutional review board–approved clinical study were performed. Using a 635-nm low-level laser of 1.0 J/cm2 supplied to the authors by the vendor, these studies were designed to determine whether alteration in adipocyte structure or function was modulated after low-level laser therapy. Cultured human preadipocytes after 60 minutes of laser therapy did not change appearance compared with nonirradiated control cells. In the porcine model, low-level laser therapy (30 minutes) was compared with traditional lipoplasty (suction-assisted lipoplasty) and ultrasound-assisted lipoplasty. From histologic and scanning electron microscopic evaluations of the lipoaspirates, no differences were observed between low-level laser therapy–derived and suction-assisted lipoplasty–derived specimens. Using exposure times of 0, 15, 30, and 60 minutes in the presence or absence of superwet wetting solution and in the absence of lipoplasty, total energy values of 0.9 mW were delivered to tissue samples at three increasing depths from each experimental site. No histologic tissue changes or specifically in adipocyte structure were observed at any depth with the longest low-level laser therapy (60 minutes with superwet fluid). Three subjects undergoing large-volume lipoplasty were exposed to superwet wetting fluid infiltration 14 minutes before and 12 minutes after, according to vendor instructions. Tissue samples from infiltrated areas were collected before suction-assisted lipoplasty and lipoaspirates from suction-assisted lipoplasty. No consistent observations of adipocyte disruptions were observed in the histologic or scanning electron microscopy photographs. These data do not support the belief that low-level laser therapy treatment before lipoplasty procedures disrupts tissue adipocyte structure.

Sutureless laparoscopic heminephrectomy using laser tissue soldering.

BACKGROUND AND PURPOSE Widespread application of laparoscopic partial nephrectomy has been limited by the lack of a reliable means of attaining hemostasis. We describe laser tissue welding using human albumin as a solder to control bleeding and seal the collecting system during laparoscopic heminephrectomy in a porcine model. MATERIALS AND METHODS Laparoscopic left lower-pole heminephrectomy was performed in five female domestic pigs after occluding the hilar vessels. Using an 810-nm pulsed diode laser (20 W), a 50% liquid albumin-indocyanine green solder was welded to the cut edge of the renal parenchyma to seal the collecting system and achieve hemostasis. Two weeks later, an identical procedure was performed on the right kidney, after which, the animals were sacrificed and both kidneys were harvested for ex vivo retrograde pyelograms and histopathologic analysis. RESULTS All 10 heminephrectomies were performed without complication. The mean operative time was 82 minutes, with an average blood loss of 43.5 mL per procedure. The mean warm ischemia time was 11.7 minutes. For each heminephrectomy, a mean of 4.2 mL of solder was welded to the cut parenchymal surface. In three of the five acute kidneys and all five 2-week kidneys, ex vivo retrograde pyelograms demonstrated no extravasation. In addition, no animal had clinical evidence of urinoma or delayed hemorrhage. Histopathologic analysis showed preservation of the renal parenchyma immediately beneath the solder. DISCUSSION Laser tissue welding provided reliable hemostasis and closure of the collecting system while protecting the underlying parenchyma from the deleterious effect of the laser during porcine laparoscopic heminephrectomy.

Laparoscopic partial nephrectomy with a diode laser: porcine results.

PURPOSE To develop a safe and effective technique for laparoscopic partial nephrectomy without need for hilar occlusion. MATERIALS AND METHODS Laparoscopic transperitoneal lower-pole partial nephrectomy was performed in five 45- to 50-kg female farm pigs using a 980-nm diode laser. Standard transperitoneal access was obtained, and a four-port approach was used to perform a laparoscopic right partial nephrectomy using a diode laser (23 W) without hilar occlusion. The pigs were allowed to recover and 2 weeks later underwent a left laparoscopic partial nephrectomy. Postoperatively, renal function was monitored by serial serum creatinine measurements. Both kidneys and ureters were removed for ex-vivo retrograde pyelograms and histologic analysis. RESULTS The 980-nm diode laser resulted in successful lower-pole partial nephrectomy without hilar occlusion in all 10 of the kidneys. In three cases, laser hemostasis was insufficient, and adjunctive hemostatic clips were necessary to stop bleeding. The mean operative time was 126 minutes, and the mean laser time was 84 minutes. An average of 23% (range 13%-33%) of the kidney parenchyma was resected. The mean blood loss was 150 mL (range 50-300 mL). There was no evidence of urinary extravasation on ex-vivo retrograde pyelograms at 2 weeks in any of the kidneys. CONCLUSION Laparoscopic partial nephrectomy without hilar occlusion using the 980-nm diode laser is feasible in the porcine model. Because adjunctive hemostatic measures may be necessary in some cases, clinical trials in humans should be limited to small exophytic tumors.

Effects of Common Laser Treatments on Hyaluronic Acid Fillers in a Porcine Model

BACKGROUND Injectable hyaluronic acid fillers (HAFs) and laser/light procedures have become increasingly popular for noninvasive facial rejuvenation in many cosmetic practices. However, the effect of laser/light treatments on HAFs is unknown. OBJECTIVE Our objective was to examine the effect of laser/light treatments on HAFs in a porcine model. METHODS The abdomens of 6 Yorkshire pigs were injected with 3 different HAFs: Restylane (Medicis, Scottsdale, AZ), Perlane (Medicis), and Juvéderm (Allergan, Santa Barbara, CA). Two weeks after injection, the injection sites were treated with 1 of 7 common laser/light ablative or nonablative devices. Following laser treatment, 8-mm punch biopsies were collected from the treated tissue and fixed for histopathologic evaluation. Sections were stained with hematoxylin-eosin and alcian blue stains for identification of the preinjected HAF. RESULTS The filler was identified in different areas of the dermis in different sections. The Sciton intense pulsed 560 nm filter (Sciton, Palo Alto, CA), the Sciton Nd: YAG, Lux1540 (Palomar Medical Technologies, Burlington, MA), or ActiveFX (Lumenis, Yokneum, Israel) treatments showed no sign of interaction with superficial or deep dermal filler. No evidence of morphologic changes to the filler or the surrounding tissues was observed. Obvious interaction between the HAFs and the laser injury was demonstrated in sections treated with the deep ablative systems fractional erbium 2940 (Profractional; Sciton) and DeepFX CO(2), (Lumenis). However, no uncharacteristic tissue injury or morphologic change in the filler was appreciated in any of the preinjected specimens. CONCLUSIONS Injected HAFs were unaffected by the nonablative laser/light and superficial ablative treatments. The more aggressive deeper laser treatments demonstrated laser/filler interaction and may have a clinical effect on the longevity of the filler and/or efficacy of laser treatments. Novel ablative fractional lasers have the capability of deep dermal penetration, and this should be taken into consideration when planning to use them in combination with soft tissue fillers for noninvasive facial rejuvenation.

TUNEL assay to characterize acute histopathological injury following treatment with the active and deep FX fractional short-pulse CO2 devices.

BACKGROUND This is a report of the histopathological evaluation of the acute damage profile in human skin following treatment with two novel short-pulsed fractional carbon dioxide resurfacing devices used independently and in combination in vivo. METHODS The panni of eight abdominoplasty patients were treated with either the Active FX, the Deep FX (Lumenis Ltd., Yokneum, Israel), or a combination of the two (Total FX) prior to the start of the excisional surgical procedure. Multiple combinations of energies, pulse widths, and densities were evaluated for each device. After surgical removal (two to five hours), each pannus was immediately biopsied and samples were processed for histopathological evaluation. RESULTS The Active FX system resulted in extensive epidermal injury with wide shallow ablation craters that, at higher fluences, extended through the basement membrane of the epidermis into the papillary dermis. The Deep FX fractional treatment caused deep microcolumns of ablation penetrating up to 3 to 4 mm from the epidermal surface into the deep reticular dermis with a variable rim of coagulated collagen surrounding each ablation column. CONCLUSIONS The in vivo histopathological evaluation of these devices furthers our understanding of the fundamental laser/tissue interaction following treatment with each device independently and in combination.

Micro-island damage with a nonablative 1540-nm Er:Glass fractional laser device in human skin.

Background and objectives  Fractional photothermolysis produces micro‐islands of thermal injury to the skin while preserving areas among treated tissue sites in order to promote wound healing. Histological changes associated with single and multiple passes of the 1540‐nm Er:Glass fractional laser were examined using in vivo human skin.

Laparoscopic Interstitial Laser Coagulation of Renal Tissue with and without Hilar Occlusion in the Porcine Model

PURPOSE To evaluate the safety and efficacy of interstitial laser coagulation (ILC), applied via a laparoscopic approach, with and without hilar occlusion in the porcine model. MATERIALS AND METHODS In nine female farm pigs, bilateral renal mobilization was performed via a transperitoneal laparoscopic approach. Using a 600- micro m bare-tip silicon diode laser fiber inserted 0.5 cm into the lower pole of each kidney, diode laser energy (wavelength 805 nm) was applied for 15 minutes at 6 W. In each pig, the left renal hilum was clamped during ILC. Animals were sacrificed immediately (N = 3) or at 2 weeks (N = 3) or 4 weeks (N = 3). The kidneys were inspected grossly, and the lesions were evaluated microscopically. Nicotinamide adenine dinucleotide (NADH) histochemical staining was performed to assess viability. RESULTS Grossly, parenchymal lesions appeared firm and white with a central zone of carbonization, cavitation, or both. Histopathology examination revealed cellular inflammation in acute lesions; chronic lesions demonstrated coagulative necrosis with progressive fibrosis. The NADH staining showed residual viable cells within the treatment zone of survival animals but not in acute animals. The mean size of the treatment zone in kidneys with unoccluded blood flow was 2.4 x 2.1 x 2.0 cm, 4.0 x 3.3 x 2.8 cm, and 3.3 x 3.5 x 2.0 cm in the acute, 2-week, and 4-week group, respectively. Hilar occlusion resulted in a slightly, but statistically insignificantly, larger lesion. In the 2-week survival group, one animal had a left subcapsular hematoma on the hilar-occluded side. In another 2-week animal, extension of the ILC zone was noted beyond the kidney into the psoas muscle. In the 4-week survival group, two animals developed gross hematuria; one had a left perinephric urinoma and urine leak noted at necropsy. CONCLUSIONS Renal ILC may represent an alternative minimally invasive technique for ablation of renal tumors. However, histologic evidence of viable cells within the treatment zone mandates refinement of the technique in the animal model before further application in humans. Hilar occlusion does not appear to enhance tissue ablation.

TUNEL Assay for Histopathologic Evaluation of Irreversible Chromosomal Damage following Nonablative Fractional Photothermolysis

Background: Fractional photothermolysis is extremely popular in skin rejuvenation and remodeling procedures. However, the extent of thermal cellular injury beyond the borders of the coagulated microcolumns produced with fractional phototherapy is undefined. Methods: Six abdominoplasty patients were pretreated with the Lux1540 Fractional Erbium device (Palomar, Inc., Burlington, Mass.) at various clinical laser settings. After tissue excision, the panni were immediately biopsied. Biopsy specimens were fixed in formalin, embedded in paraffin, sectioned, and evaluated with the terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick end labeling (TUNEL) procedure for cellular necrosis/apoptosis. Tissue was sectioned horizontally and longitudinally to help define the depth and distribution of the microcolumns of injury in a three-dimensional plane. Results: The extent of cellular necrosis/apoptosis at variable depths within the epidermis and dermis was demonstrated successfully with the TUNEL technique. After the Lux1540 treatment, TUNEL-positive nuclei were identified in a vertically oriented fashion that extended from the epidermis into the papillary and reticular dermis, highlighting the areas of injury. The TUNEL-positive nuclei defined lesions that were approximately 175 to 225 &mgr;m in diameter and penetrated to variable depths (200 to 900 &mgr;m), depending on the fluence used for treatment (18 to 100 mJ). Conclusions: TUNEL immunofluorescent labeling provided an accurate assessment of cellular damage within and surrounding the microthermal zones of coagulated collagen with respect to column depth and width. Because of its specificity, the TUNEL assay can be a useful adjunct to other histologic stains used to characterize cellular damage and matrix denaturation in skin treated with any fractional ablative or nonablative laser device.

An intra-individual quantitative assessment of acute laser injury patterns in facial versus abdominal skin

Clinical laser settings have traditionally been calibrated on abdominal skin to predict and anticipate patterns of injuries in facial skin. This experimental approach has limitations as facial skin and abdominal skin have differences that may influence the depth of laser injury.

Nonsurgical delay of dorsal rat cutaneous flap using a long-pulsed 1064-nm Nd:YAG laser with a contact cooling device.

Background: This study evaluated the efficiency of a long-pulsed neodymium:yttrium-aluminum-garnet laser, operating at 1064 nm and equipped with a contact cooling device, in the delay of a caudally based dorsal rat skin flap (10 × 3 cm). This laser has deeper tissue penetration and has not been used for this purpose before. Methods: Twelve male Sprague-Dawley rats were used in each of six groups. The delay effects of three different laser treatment patterns (only longitudinal borders, cephalic and longitudinal borders, and entire surface of the 10 × 3-cm flap) were compared with an acute untreated control flap as well as two surgical delay methods (incision of longitudinal borders and incision of longitudinal borders plus flap undermining). The laser effects on the cutaneous vasculature and perfusion were assessed by intravenous fluorescein injection, histologic study, microangiography, and in vivo real-time video monitoring. Results: Selective thermocoagulation of subdermal vessels was achieved using a 6-mm spot, 140-J/cm2 fluence, and 40-msec pulse width. In the cephalic and longitudinal borders laser-treated group, a delay effect was achieved. The maximum delay effect was achieved by the surgical delay group that used the method of incision of the longitudinal borders plus flap undermining. Laser treatment of only the longitudinal borders did not improve flap survival, whereas treatment of the entire flap surface significantly reduced flap survival. Conclusion: Nonsurgical delay of a dorsal rat cutaneous flap is possible by selective occlusion of the subdermal plexus at the longitudinal and cephalic borders of the planned flap using a long-pulsed 1064-nm neodymium:yttrium-aluminum-garnet laser equipped with a contact cooling device.