Pharmacologic enhancement of composite graft survival

Reducing Risks of Graft Failure for Composite Skin–Cartilage Grafts

Facial skin defects pose unique challenges for the reconstructive surgeon. Aesthetically complex areas involving a free margin-such as the ear, eyelid, columella, columella-lobule interface, soft tissue triangle, alar rim, and internal nasal lining-are particularly demanding, as secondary soft tissue contracture in these locations can lead to a very poor cosmetic outcome. In these cases, composite grafts offer an ideal combination of soft tissue coverage and structural rigidity, all accomplished in a single-stage surgery. Composite grafts are often underused in facial reconstructive surgery due to the tenuous blood supply and high reported rates of graft failure.

Effects of hyperbaric oxygen on graft survival outcomes in composite grafting for amputated fingertip injury

BACKGROUND

Fingertip injuries are the most common type of traumatic injury treated at emergency departments and require prompt and adequate interventions for favorable wound survival outcomes. Hyperbaric oxygen (HBO2) therapy is well known for its many positive effects on wound healing. We hypothesized that treatment with HBO2 would improve the graft survival outcomes of amputated fingertip injuries treated with composite grafts.

METHODS

This retrospective observational study included fingertip amputations that were treated between January 2013 and December 2017. A conventional group and an HBO2 therapy group were statistically compared to evaluate the effect of HBO2 treatment. Graft survival was categorized as either success or failure.

RESULTS

Among 55 cases (digits), 34 digits were conventionally treated, while 21 digits were treated with HBO2. No statistically significant differences were observed between the groups with regard to general characteristics. Among patients with guillotine-type injuries, the composite graft success rate was statistically significantly higher in the group that received HBO2 therapy than in the conventional group (P=0.0337). Overall, the HBO2 group also demonstrated a statistically significantly shorter healing time than the conventional group (P=0.0075). As such, HBO2 treatment facilitates composite graft survival in cases of fingertip injury.

CONCLUSIONS

HBO2 treatment was associated with an increased composite graft survival rate in guillotine-type fingertip injuries and reduced the time required for grafts to heal.

Effect of Polydeoxyribonucleotide on Chondrocutaneous Composite Grafts Survival

BACKGROUND

A composite graft is considered the best choice for facial reconstruction because of proper texture, color, and simple surgical techniques. However, due to revascularization by the bridging phenomenon, it has limitations with unpredictable survival rates and can be applied only to small defects. Polydeoxyribonucleotide (PDRN) plays an important role in multiple vascular processes such as angiogenesis via production of a vascular endothelial growth factor and by providing an anti-inflammatory effect by reducing pro-inflammatory cytokines through the adenosine A2 receptor stimulation. Thus, here, we investigated PDRN as a supportive method to improve survival of composite grafts.

METHODS

Chondrocutaneous composite grafts were applied to both ears of 20 New Zealand White rabbits. The grafts were then rotated and returned to their positions to prevent the original blood flow from the base of the grafts. On postoperative days 1, 3, 6, 9, and 12, PDRN was injected intradermally into the experimental group (20 ears) and normal saline was injected into the control group (20 ears) to exclude bias of pressure effect. After 12 days, graft survival and cutaneous blood flow were examined under laser speckle contrast imaging.

RESULTS

Gross observation indicated that the graft viability in the PDRN group was significantly higher than that in the control group (p < 0.05). Through laser speckle contrast imaging, signal intensity increased from the periphery and progressed centrally with treatment.

CONCLUSION

Our findings suggest that PDRN may increase blood flow around at the base of the graft, restore the perfusion, and improve the survival of the composite grafts.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Skin and Composite Grafting Techniques in Facial Reconstruction for Skin Cancer

Skin and composite grafting provide effective resurfacing and reconstruction for cutaneous defects after excision of the malignancy. The goal is to restore a natural appearance and function while preventing distortion of the eyelid, nose, or lips. With careful planning and attention to aesthetic subunits, the surgeon can camouflage incisions and avoid blunting aesthetically sensitive sulci. The surgical plan is also informed by the pathology, as basal or squamous cell carcinomas removed by Mohs micrographic excision have different prognostic and logistical considerations from melanoma. Skin and composite grafting are useful as stand-alone procedures or may complement local flaps and other soft tissue reconstructions.

Composite grafting for pediatric fingertip injuries

BACKGROUND

Fingertip injuries are common in the pediatric population. Composite grafting is a frequently used technique for distal amputations in children given the reported success rate. We sought to study the early clinical results of composite grafting for fingertip injuries in the pediatric population.

METHODS

A retrospective review was performed over a 5-year period at a tertiary care pediatric hospital to identify those patients who underwent composite grafting of fingertip injuries. Patients were included if they were 18 years old or younger and sustained an injury distal to the distal interphalangeal joint (or thumb interphalangeal joint). Demographic information was recorded. Graft viability was characterized as no take, partial take, or complete take. The number of secondary procedures and number and duration of follow-up appointments were recorded. Hypothesis testing was done using ordinal logistic regression analysis.

RESULTS

Thirty-nine patients underwent fingertip composite grafting. The mean age was 5.9 years (1-18 years); there were 24 males (61.5 %) and 15 females (38.5 %). Thirteen patients had no graft take (33.3 %), 23 patients had partial take (59.0 %), and three patients had complete take (7.7 %). Only four patients underwent secondary revision (10 %). The median number of follow-up appointments was 3 and the average follow-up time was 4.5 months. Age did not appear to have a statistically significant influence on graft take.

CONCLUSIONS

Fingertip composite grafts rarely take completely even in young children. Despite poor viability, however, most patients will have at least partial graft take and do not undergo additional reconstructive procedures.

The effect of platelet-rich plasma on survival of the composite graft and the proper time of injection in a rabbit ear composite graft model

Background

Administration of growth factors has been associated with increased viability of composite grafts greater than 1-cm in diameter. Platelet-rich plasma (PRP) contains many of the growth factors studied. In this study, we evaluate the effect of PRP injection on composite graft viability and the proper time for injection.

Methods

A total of 24 New Zealand White rabbits were divided into four groups. Autologous PRP was injected into the recipient sites three days before grafting in group 1, on the day of grafting in group 2, and three days after grafting in group 3. Group 4 served as control without PRP administration. Auricular composite grafts of 3-cm diameter were harvested and grafted back into place after being rotated 180 degrees. Median graft viability and microvessel density were evaluated at day 21 of graft via macroscopic photographs and immunofluorescent staining, respectively.

Results

The median graft survival rate was 97.8% in group 1, 69.2% in group 2, 55.7% in group 3, and 40.8% in the control group. The median vessel counts were 34 (per ×200 HPF) in group 1, 24.5 in group 2, 19.5 in group 3, and 10.5 in the control group.

Conclusions

This study demonstrates that PRP administration is associated with increased composite graft viability. All experimental groups showed a significantly higher survival rate and microvessel density, compared with the control group. Pre-administration of PRP was followed by the highest graft survival rate and revascularization. PRP treatments are minimally invasive, fast, easily applicable, and inexpensive, and offer a potential clinical pathway to larger composite grafts.

Repair of Small Nasal Defects

Nasal reconstruction is a challenging yet rewarding endeavor. Repair of nasal defects requires an appreciation of variations in nasal skin thickness and the influence of these differences on potential reconstructive methods. Multiple factors help determine the optimal method of repair, including the size of the defect relative to the amount of remaining skin, the depth and location of the defect, and the strength of the underlying nasal framework. Maintaining symmetry, contour, and function is essential for a successful nasal reconstruction.

Use of hyperbaric oxygen to enhance auricular composite graft survival in the rabbit model

OBJECTIVE

To evaluate the efficacy of using hyperbaric oxygen to enhance auricular composite graft survival via a prospective, randomized, placebo-controlled, double-blind study.

DESIGN

Eighteen New Zealand White rabbits were randomly assigned to treatment (n = 9) and control (n = 9) groups after amputation and reattachment of 20 x 10-mm auricular composite grafts. The treatment group received twice-daily hyperbaric oxygen treatments for 5 days. The control group received twice-daily hyperbaric room-air treatments for 5 days. After 21 days, digital photographs of the composite grafts were taken and compared with photographs taken on the day of surgery. From these photographs, digital imaging software was used to calculate the percentage of graft survival.

RESULTS

The treated group (18 ears) had a mean +/- SD graft survival area of 80.67% +/- 19%, whereas the control group (18 ears) had a mean +/- SD graft survival area of 26.33% +/- 29%. Variance analysis with the Snedecor test allowed the comparison of the groups. The paired, 2-tailed t test proved a significant difference (P<.001) between groups.

CONCLUSION

Hyperbaric oxygen therapy is an effective way to enhance the survival of 2-cm auricular composite grafts.

Repair of small nasal defects

Nasal reconstruction is a challenging yet rewarding endeavor. Repair of nasal defects requires an appreciation of variations in nasal skin thickness and the influence of these differences on potential reconstructive methods. Multiple factors help determine the optimal method of repair, including the size of the defect relative to the amount of remaining skin, the depth and location of the defect, and the strength of the underlying nasal framework. Maintaining symmetry, contour, and function is essential for a successful nasal reconstruction.

The effect of hyperbaric oxygen therapy on composite graft survival

Auricular composite grafts are a useful reconstructive option, particularly for nasal reconstruction. This study evaluates the effect of hyperbaric oxygen (HBO) therapy on auricular composite graft survival in rabbits. Circular chondrocutaneous composite grafts of 0.5, 1, or 2 cm in diameter were resected from the ears of rabbits. The grafts were sutured back into position. Half the rabbits in each group received HBO postoperatively, consisting of 90 minutes at 2.4 atm. Rabbits received 7 treatments in 5 days. Control rabbits did not receive HBO. On day 21 the percentage area of graft survival was calculated from gross and histologic examination. Two-centimeter grafts treated with HBO (n = 8) had a mean graft survival rate of 85.8 +/- 15.7% compared with a survival rate of 51.31 +/- 38.5% for the control group (n = 8; P = 0.0478). There was no such benefit in smaller grafts. HBO could prove clinically useful for larger composite grafts.

Composite earlobe grafts to reconstruct the lateral nasal ala and sill

Numerous operations have been described to address the unilateral cleft lip deformity. One area that has not received significant attention is the deficient join between the nasal ala and the upper lip. Several surgeons have advocated detaching the ala and rotating it medially to restore the nasal sill and decrease the alar flare. Unfortunately, many children with clefts do not have enough available tissue to perform these maneuvers without compromising the nostril opening. In this article, the authors present a technique using composite earlobe grafts with sandwiched cartilage grafts to restore symmetry with the contralateral nostril. This technique has also been used in adult patients undergoing reconstruction because of cancer ablation or traumatic injuries. All patients received adjuvant hyperbaric oxygen therapy.

Enhancement of auricular composite graft survival with hyperbaric oxygen therapy

OBJECTIVE

To continue investigation regarding the efficacy of hyperbaric oxygen (HBO) therapy in improving survival of reattached auricular composite grafts.

DESIGN

A prospective, randomized, double-blind study using 20 New Zealand albino rabbits randomized to a treatment or control group. The treatment group received 30 HBO treatments over 19 days following amputation and reattachment of composite auricular grafts. The control group received standard care. Ears were examined grossly and microscopically on postoperative day 21 to determine the percentage of graft survival.

RESULTS

The mean percentage of graft survival for the 2 separate grafts (a larger 1.5 x 4.0-cm and a smaller 1.0 x 3.0-cm graft) in the treatment group was 26.5% and 27.9%, respectively. The mean percentage of graft survival for the larger and smaller graft in the control group was 9.7% and 14.0%, respectively. An analysis of variance test was used to evaluate this difference, which was found to be statistically significant (P =.001).

CONCLUSIONS

This study represents a continued investigation following a pilot study, which suggested some enhancement of composite graft survival with the use of HBO therapy in the rabbit ear. Both experiments have demonstrated a slight survival benefit using HBO therapy in auricular composite grafts in the rabbit model.

Pharmacological characterization of vasomotor activity of human musculocutaneous perforator artery and vein

Vasospasm is one of the main causes of skin ischemic necrosis in cutaneous and musculocutaneous flap surgery, but the pathogenic mechanism is unclear. We planned to test the hypothesis derived from clinical impression that veins are more susceptible to vasospasm than arteries in flap surgery and, once established, that venous vasospasm is difficult to resolve and more detrimental than arterial vasospasm. To this end, we investigated the differences in sensitivity to vasoconstrictors and vasodilators between the human musculocutaneous perforator (MCP) artery and vein by measuring the isometric tension of arterial and venous rings suspended in organ chambers. Vascular contraction was expressed as a percentage of the tension induced by 50 mM KCl. Relaxation was expressed as a percentage of contraction induced by a submaximal concentration (3 x 10(-9) M) of endothelin-1 (ET-1). We observed that the vasoconstrictor potency of norepinephrine was significantly higher in the MCP vein than in the MCP artery. The vasoconstrictor potency of ET-1 and the thromboxane A(2) mimetic U-46619 were similar in the MCP vein and artery, but the maximal contraction induced by ET-1 and U-46619 was significantly higher in the MCP vein than in the MCP artery. On the other hand, the MCP vein was less sensitive than the MCP artery to the relaxation effect of nitroglycerin, nifedipine, and lidocaine. These differences between the human MCP artery and vein in response to vasoactive agents lend support to the clinical impression in flap surgery that veins appear to be more susceptible to vasospasm than arteries and venous vasospasm seems to be more difficult to resolve than arterial vasospasm in cutaneous and musculocutaneous flap surgery.

Pilot study to evaluate the efficacy of hyperbaric oxygen therapy in improving the survival of reattached auricular composite grafts in the New Zealand White rabbit

OBJECTIVE

This investigation is a prospective, randomized, blinded study seeking to evaluate the efficacy of hyperbaric oxygen (HBO) therapy in improving the survival of the reattached auricular composite graft.

STUDY DESIGN

Twenty New Zealand White rabbits were randomly assigned to control (10) and treatment (10) groups in a prospective fashion. After amputation and reattachment of measured segments of each ear, the treatment group received 14 HBO treatments for 10 days. The control group received only standard postoperative care. On postoperative day 18, the surviving composite grafts were measured, recorded, and statistically analyzed.

RESULTS

The mean percentage of graft survival for the control group was 0.31% (range 0%-2.5%), and the mean for the group receiving HBO was 15.94% (range 0%-38%). A median test was used to evaluate this difference, which was found to be statistically significant (P = 0057).

CONCLUSION

Our study appears to indicate a possible survival benefit for the composite grafts in those rabbits that received HBO treatments. We believe that there are several significant difficulties with the rabbit as a model for this study, but we are encouraged at this point that a limited measurable benefit was observed. Further investigations with HBO appear to be warranted at this time.

Quantification of rebound edema after steroid treatment

OBJECTIVE

Return of edema after abrupt discontinuation of steroid treatment has never been studied or quantified. The purpose of this study was to measure the effect of abrupt cessation and tapering doses of steroids on tissue water content (TWC) in a rat skin flap model.

DESIGN

A randomized controlled animal trial was designed to study the effects of discontinuation of steroid on skin flap edema. The animals were assigned to a control group (C), a steroid group (S), an abrupt steroid cessation (SC) group, or a tapering steroid (ST) group.

MAIN OUTCOME MEASURES

In each group the skin flaps were biopsied at 30 and 36 hours. TWC was determined by a biopsy-drying technique.

RESULTS

A significant difference (P = 0.05) was found between the C and S groups and between the SC and S groups at both 30 and 36 hours, with the C group having the highest TWC. No significant difference was noted between the SC and C groups. The ST group had significantly less edema than the C group and similar TWC to that of the S group.

CONCLUSION

Edema rebounded in the skin flaps after abrupt cessation of steroids (SC was not different from C), presumably because of destabilization of inflammatory mediators. The rebound effect was not observed in the ST group. The control of rebound edema by a tapering steroid protocol may be important in skin flap survival and may have implications for the management of airway edema.

Effects of dimethylthiourea, melatonin, and hyperbaric oxygen therapy on the survival of reimplanted rabbit auricular composite grafts

Microvascular reconstruction currently offers the best chance of survival for an ear segment reimplanted after amputation. Unfortunately, this technique is possible only when ear and scalp vessels remain intact. Direct reattachment of the amputated segment as a composite graft is less reliable because survival is poor for grafts larger than 2 cm in diameter. However, if survival could be improved, direct reattachment would be an attractive alternative in situations in which microsurgical revascularization is not possible. Certain pharmacologic agents have been shown to enhance the survival of composite grafts. This study demonstrated that hyperbaric oxygen, dimethylthiourea, and melatonin significantly affected the survival of reimplanted auricular composite grafts at day 7. However, by day 21 the average percentage of survival for all groups approached 13% to 14%. Dimethylthiourea had the most beneficial effect on survival early in the postoperative period, whereas the hyperbaric oxygen group demonstrated the poorest survival.

Effects of angiogenic growth factors and a penetrance enhancer on composite grafts

Skin-cartilage composite grafts are invaluable tissues used in facial reconstruction, yet their survival is unpredictable beyond a 1-cm diameter. In this study, the angiogenic growth factors basic fibroblast growth factor (bFGF) and endothelial cell growth factor (ECGF) and a penetrance enhancer (dimethyl sulfoxide [DMSO]) were applied to composite grafts to determine their effects on survival and vascularization. We applied ECGF, bFGF, and DMSO either topically or by intradermal injection to 120 auricular composite grafts (3.0 cm diameter) in New Zealand White rabbits. Dermabrasion was performed in 2 groups to attempt to increase transdermal delivery. Graft viability and vascularity were evaluated 3 weeks later by template analysis and angiography. In the results, ECGF and bFGF, when grouped together, had a 40% increase in vascular ingrowth as compared to controls (p < .001). However, neither ECGF nor bFGF increased graft survival. A coincidental finding was that DMSO with dermabrasion significantly improved graft viability (>100%) with or without an angiogenic agent (p < .02). The potential of DMSO with dermabrasion to increase composite graft viability warrants further investigation.

Efficacy of steroids and hyperbaric oxygen on survival of dorsal skin flaps in rats

This study was designed to determine if steroids improved skin flap survival in rats, and if steroids and hyperbaric oxygen (HBO) showed an additive beneficial effect. Cranially based, 3 x 9 cm dorsal skin flaps were raised in 60 adult rats. All animals received either intramuscular methylprednisolone (30 mg/kg) or an equal volume of intramuscular saline solution placebo 24 hours and 1 hour before, and 24 hours and 48 hours after, flap elevation. Treatment for animals receiving HBO was begun within 5 hours after flap elevation. The regimen consisted of two 90-minute treatments of 100% oxygen at 2.4 atm separated by 5-hour intervals or room air per day for 3 consecutive days. The 60 rats were divided equally into four treatment groups, as follows: group A, flap elevation alone (control); group B, flap plus steroids; group C, flap plus HBO; and group D, flap plus steroids plus HBO. Surviving flap length was measured by visual inspection 7 days after flap elevation. The mean surviving flap length for group A was 4.9 cm, for group B it was 6.4 cm, for group C it was 6.7 cm, and for group D it was 6.5 cm. The approximately 30% to 36% improvement in surviving flap length was highly statistically significant (p less than 0.006) when compared with controls. However, no statistically significant difference was found between the three treatment modalities. These findings indicate that in a rat dorsal skin flap model, perioperative steroids improve skin flap viability, and that steroids alone are as efficacious as HBO and as steroids combined with HBO.