Incidence of flap procedures in the management of burn patients.

Increased survival of burn patients presents opportunities for reconstructive strategies to improve outcomes in management of acute and secondary burn injuries. To assess one such strategy, namely flap reconstruction, we reviewed cases performed during the first 4.5 years of the JMS Burn and Reconstruction Center. We found that flap procedures accounted for 0.8% of acute cases (23 of 2723 procedures) and 33% of secondary cases (260 of 790 procedures). This initial finding shows that in this practice flap procedures are applied to a small number of acute problems while flap procedures comprise 33% of secondary procedures. Reconstructive flap surgery plays a measurable role in burn treatment at this center. Further study of outcomes and timing could lead to better understanding of optimal strategies for flap reconstruction in burns.

Effect of sildenafil on peripheral nerve regeneration.

In this study, we investigated whether sildenafil, a cyclic guanosine monophosphate-dependent phospodiesterase-5 inhibitor, could promote functional nerve regeneration after surgical section and repair of the sciatic nerve in rats. Nerve regeneration was studied in a rat sciatic nerve transected and repair model. The animals were randomly assigned to one of the following 3 treatment groups (n = 20/group): sildenafil-treated group 1 (5 mg/kg/d subcutaneously, for 7 days), sildenafil-treated group 2 (5 mg/kg/d subcutaneously, for 42 days), and control group given saline solution (once per day subcutaneously). Walking track analysis, electromyography, and histological evaluation were performed on day 90 after repair operation. The results showed that the sciatic functional index of sildenafil-treated group 1 (data) was slightly better than that of sildenafil-treated group 2 (data) and control group (data) on postoperative day 90. However, the difference was not statistically significant (P = 0.073). No significant differences of the motor nerve conduction velocity were found between experimental groups [18 (2.4) and 20 (4.1 m/s)] and saline control group [19.5 (3.0) m/s] (P = 0.68). Comparison of myelinated axon count of regenerated nerve of the rat between the sildenafil-treated group 1, sildenafil-treated group 2, and saline group was also not significantly different (P = 0.56). In conclusion, administration of sildenafil after nerve repair surgery was found to have positive but insignificant effects on several parameters of nerve regeneration. Further studies could clarify this trend suggesting enhanced nerve regeneration mediated by sildenafil.

Effects of comorbidities and implant reinforcement on outcomes after component reconstruction of the abdominal wall.

A series of patients undergoing component reconstruction of midline abdominal wall separations was analyzed to assess the effects of comorbidities and biological implant reinforcements on outcomes. Thirty-nine patients were identified as fitting the technical definition of component repairs and having at least 12 months of documented follow-up. This group of procedures had a 67% primary healing rate, 18% and 13% rate of major and minor complications, respectively, and a total of 90% successful reconstructions after secondary procedures. Variables assessed for outcome influences included etiology of the abdominal wall separation, obesity, diabetes, hypertension, and biological implant reinforcements, including absorbable mesh and biological implants. None of these factors significantly influenced outcome, although first time repairs and reinforced repairs had suggestively higher success rates. This data suggest that comorbidities do not influence outcomes of component abdominal wall repairs, and assessments of the problem and ongoing technical refinements of the procedure should be studied further.

Treatment of axillary hidradenitis with transposition flaps: a 6-year experience.

In our series, 15 patients underwent 21 procedures for wide resection of axillary hidradenitis with coverage by posteriorly based Limberg transposition flaps. Twenty flaps (95%) healed without axillary contracture. One failed flap required skin graft coverage. Transposition flap coverage in these patients was a reliable, single-stage reconstruction allowing prompt arm movement.

The 'Ten Test': application and limitations in assessing sensory function in the paediatric hand.

BACKGROUND: The Ten Test, first described in 1997 by Strauch et al., is a simple, rapid, reliable and sensitive method to evaluate hand sensibility in adults. In this study, we validated its use in children. METHODS: We asked patients to rate sensibility elicited by a light moving touch on the palmar surface of digits in reference to sensibility elicited by the same touch in a digit confirmed as normal. RESULTS: A total of 73 subjects (age range: 1-12 years) were tested. Patients under age 5 years were significantly less likely to complete the test. The kappa statistic for the Ten Test in nine subjects, each tested separately by two examiners, demonstrated very strong inter-observer reliability (kappa=1.0, p<0.003). CONCLUSIONS: The Ten Test is a simple, validated, non-threatening method to evaluate hand sensibility in children and adolescents. We recommend its clinical use in patients age 5 years and older.

Repair of partial nerve injury by bypass nerve grafting with end-to-side neurorrhaphy.

The purpose of this study was to investigate the efficacy of bypass nerve grafting with end-to-side neurorrhaphy in repair of the partial nerve injury in a rabbit model. Thirty-six adult male New Zealand rabbits were divided into three groups. A partial nerve injury was created by removal of a segment of the lateral fascicle of the left peroneal nerve. In group one, the injured nerve was repaired with nerve graft bypassing the injury site in an end-to-side fashion 4 weeks after injury. In group two, the injured nerve was repaired with end-to-end interpositional nerve grafting 6 weeks after injury. The injured nerve without repair was used as the control. Sixteen weeks after nerve repair, in groups one and two, and 20 weeks after the initial nerve injury in the control group, the nerves were dissected for electrophysiological examination and biopsied for histology and molecular markers expression. The nerve repair with interpositional nerve grafting achieved maximal functional recovery. However, motor nerve conduction velocity and compound motor action potential in nerve repair with bypass nerve grafting were significantly higher than that in the nerve injury without repair. Histologically, the regenerated myelinated axons and unmyelinated axons were present in the distal peroneal nerves in the bypass nerve grafts. The axon counts in nerve repair with the bypass nerve grafting were also significantly higher than that in the nerve injury without repair. The comparisons of the ciliary neurotrophic factor and the calcitonin gene-related peptide gene expressions between nerves with and without repair were significantly different. End-to-side bypass nerve grafting can significantly improve functional recovery in the nerve with partial injury and may be a useful repair strategy in neuromas-in-continuity.

A case of latissimus dorsi pedicle arising from the lateral thoracic vessels.

The thoracodorsal system represents a versatile, yet reliable system for the harvest of tissues for microsurgical transplantation. Also, the donor vessel anatomy is generally thought to be highly predictable in terms of topography and branching patterns. In this article we describe for the first time the occurrence of a branching pattern during a clinical harvest of the latissimus dorsi muscle flap, previously encountered only in cadaver dissections. We compare our intraoperative findings with published anatomical investigations and discuss the implications of this particular variation of the blood supply to the latissimus dorsi muscle for clinical practice.

Hospital income from patients managed through a center for microsurgery and complex reconstruction.

We analyzed a 3-year period of hospital income derived from patients managed through a Center for Microsurgery and Complex Reconstruction. Revenues for these 3 years were $1,505,748, $2,158,102, and $2,029,193, respectively. Profits were $487,322 (32%), $459,856 (21%), and $26,552 (1%) over the same period, with the last year's decrease in profits coinciding with increased costs at a time of administrative reorganization and practice disruptions in the university hospital. This study demonstrates that this patient group can generate consistent revenues and substantial profits in years of institutional stability with widely distributed indirect costs.

Improvement of full-thickness skin graft survival by application of vascular endothelial growth factor in rats.

The effect of vascular endothelial growth factor (VEGF) on skin graft survival was studied in rats. Models of skin grafting on muscle and periosteum were designed. For the study of skin grafting on muscle model, 32 rats were divided into 4 groups. VEGF was administrated systemically after skin graft placement intrafascially injected into the recipient bed at the time of graft placement and topically applied to the recipient bed at the time of graft placement. Control groups consisted of grafts placed on sites without systemic or local VEGF treatment. With the study of skin grafting on periosteum, 40 rats were divided into 4 groups. VEGF was systemically, intraperiosteally, and topically applied to the recipient bed. The control animals received no treatment. On the fifth postoperative day, the survival area of each skin graft was measured and the graft was harvested for histology with CD31 immunohistochemical staining. The results showed that in skin grafting on muscle model, the mean viable percentage of the skin graft was 66.1% +/- 10.2% in the group receiving systemic application of VEGF and 56.1% +/- 9.8% in the group receiving VEGF intrafascia injection. The survival percentages were significantly higher than those found in the control group (22.5% +/- 7.7%) and the group with VEGF topical application (30.8% +/- 4.1%). In skin grafting on periosteum, the group receiving VEGF intraperiosteum injection reached a survival percentage of 50.5% +/- 4.3%, significantly higher than the groups with VEGF systemic application (28.7 +/- 5.5%), VEGF topical application (32.5% +/- 4.8%), and the control (25.8% +/- 6.0%). Histology showed that sections taken from grafts with VEGF intrafascia and intraperiosteum treatment revealed angiogenesis. The data demonstrated that administration of VEGF into the either muscular or periosteal recipient beds for skin grafting can improve the skin graft survival.

Immediate and delayed use of arteriovenous fistulae in microsurgical flap procedures: a clinical series and review of published cases.

In microsurgical flap procedures, creation of an arteriovenous fistula (AVF) is a technique of vein grafting where the vein graft is connected to recipient vessels as a flow-through loop prior to harvest and inset of the flap. Controversy exists whether this technique can be used as a 2-stage procedure with the loop and flap transfer accomplished in sequential operations or if the loop and flap transfer should be performed in a single operation. We performed 12 consecutive 1-stage AVF-flap procedures, with 1 flap failure. We combined this series with previously published reports to compare outcomes of 1-stage and 2-stage procedures. We found no significant difference in flap outcomes or complication rates between the 2 strategies. We conclude from our experience and this analysis that single-stage AVF-flap procedures are the optimum application of this technique.

Recipient vessels for microsurgical flaps to the groin and pelvis: a review.

Reconstruction of large defects of the pelvis and groin sometimes requires microsurgical flaps when the otherwise rich supply of local options fails to be sufficient in difficult and complicated cases. Recipient vessels for microsurgical flaps to the groin and pelvis are important elements in planning such procedures. Seven groups have reported pelvis and groin microsurgical flap cases, and their recipient vessels have included the superior and inferior gluteal vessels, the femoral vessels, the deep perforators of the femoral system, the inferior epigastric vessels, intra-abdominal vessels, and interpositional vein grafts to distant recipient vessels. This review summarizes their experience and describes the recipient vessel options in the pelvic and groin region.

Muscle flap mass preservation with end-to-side neurorrhaphy: an experimental study.

The authors examined the preservation of rat gracilis muscle flap mass after motor and sensory end-to-side neurorrhaphy. The rat gracilis muscle flap model was designed based on a previous study. Twenty-four Sprague-Dawley rats were divided into three groups. In Group 1 (n = 8), the flap was denervated by transecting the obturator nerve. In Group 2 (n = 8), the flap was reinnervated by coapting the proximal saphenous nerve to the distal obturator nerve. In Group 3 (n = 8), the flap was reinnervated by coapting the motor branch of the femoral nerve to the distal stump of the obturator nerve. At 6 months postoperatively, the gracilis muscle flaps were examined, harvested, and weighed individually. Results showed that the flaps with motor nerve reinnervation retained good bulk, with a weight of 634.0 +/- 65.1 gm, which was statistically significantly higher than the denervated group (457.5 +/- 125.3 gm, p < 0.01). However, muscle mass preservation in the sensory reinnervated group (606.9 +/- 209.1 gm) was not significantly different, compared to the denervated group. Histology revealed atrophic changes in the denervated group, compared to the sensory and motor-reinnervated groups. The authors concluded that muscle mass can be preserved by end-to-side nerve repair. Motor nerve reinnervation is able to better arrest atrophic changes of the muscle flaps.

Vascular endothelium growth factor, surgical delay, and skin flap survival.

OBJECTIVE: Cytokines may be a mechanism by which surgical delay can increase flap survival. We previously found that preoperative vascular endothelium growth factor (VEGF) administration in the rat transverse rectus abdominis myocutaneous (TRAM) flap could improve skin paddle survival. In this study, we used partial elevation of the rat TRAM flap as a surgical delay to assess endogenous cytokine expression and tissue survival comparable to undelayed TRAM flaps. METHODS: In Part I, TRAM flaps underwent surgical delay procedures; 7 days later, the flaps were completely elevated and reinset. At the same time, other flaps were raised and reinset without delay. Skin paddle survival in both groups was evaluated at 7 days. In Part II, skin biopsies from TRAM zones I to IV were taken at the time of delay and at intervals of 12, 24, 48, and 72 hours. Specimens were assessed for selected cytokine gene expression by reverse transcription-polymerase chain reaction analysis (TR-PCR). RESULTS: Surgical delay significantly (P < 0.001) increased skin paddle survival in the delayed TRAM flaps (16.14 +/- 1.53 cm, 81.9%) compared with undelayed flaps (7.68 +/- 3.16 cm, 40.9%). TGF-beta and PDGF expressions were not changed by surgical delay, but basic fibroblast growth factor (bFGF) and VEGF expressions increased significantly (P < 0.05 and P < 0.01) after delay. CONCLUSIONS: In the rat TRAM model, surgical delay resulted in increased VEGF expression and increased skin paddle survival. These results correlate with previous studies showing the preoperative injection of VEGF increases skin paddle survival. VEGF may be an important element in the delay phenomenon and may be an agent for pharmacological delay.

Regulation of inducible nitric oxide synthase in ischemic preconditioning of muscle flap in a rat model.

PURPOSE: Ischemic preconditioning has been shown to influence flap tolerance to prolonged ischemia. Nitric oxide (NO) synthesis is one of the proposed mechanisms involved in ischemic preconditioning. In this study, the molecular marker of NO is examined in correlation with ischemic preconditioning on improving muscle flap survival. METHODS: Fifty male Sprague-Dawley rats were randomized into experimental and control groups. The gracilis muscle flap with femoral vascular pedicle was used as a flap model. Ischemic preconditioning consisted of 3 sequences of clamping the pedicle for 10 minutes followed by 10 minutes of reperfusion for a total of 1 hour. In part I, the experimental group (n = 10) underwent ischemic preconditioning for 1 hour. In the control group (n = 10), the flaps were dissected without clamping of the pedicle. Both groups were then subjected to 4 hours of global ischemia by continuous pedicle clamping, after which the flaps were sutured to their beds. On postoperative day 3, flap survival was determined by gross and histologic examinations. The evaluators were blinded to the treatment. In part II, the experimental group (n = 12) underwent ischemic preconditioning, while the control group (n = 12) did not. The flaps from each group were harvested for inducible nitric oxide synthase (iNOS) gene expression using reverse transcriptase-polymerase chain reaction at the end of 1 hour after reperfusion and at 4 hours of global ischemia. RESULTS: The results indicated a significantly higher survival rate in the experimental group than in the control group (90 versus 50%, P < 0.05). iNOS gene expression was significantly higher in the experimental group than in the control group at 1 hour after ischemic preconditioning (0.73+/-0.18 versus 0.26+/-0.11, P < 0.01). However, after 4 hours of global ischemia, iNOS expression in the control group was statistically higher than in the experimental group (0.83+/-0.16 versus 0.26+/-0.07, P < 0.01). CONCLUSIONS: We conclude that ischemic preconditioning can enhance flap tolerance to ischemia-reperfusion injury and improve flap viability rate. This study provides evidence that the regulation of NOS may play a role in ischemic preconditioning phenomenon and warrants further investigation.

Ciliary neurotrophic factor for acceleration of peripheral nerve regeneration: an experimental study.

The objective of this study was to investigate the effect of topically administrated ciliary neurotrophic factor (CNTF) on peripheral nerve regeneration. Sixty-eight Sprague Dawley rats underwent a unilateral sciatic nerve transection and silicon tubulization, with a 10-mm gap between the proximal and distal nerve stumps. Recombinant human CNTF (1 mg/kg) was injected into the rats of the experimental group, while normal saline was injected into the control group animals. Electrophysiologic and histologic studies, including nerve morphometry and electron microscopic observation, were performed at 1, 3, and 4 months postoperatively. HRP tracing was carried out at 3 months postoperatively to label spinal-cord, ventral-horn, and dorsal-root ganglia. The results revealed that CNTF-treated animals showed a higher motor nerve conduction velocity of the sciatic nerve and a higher muscle action potential amplitude of the anterior tibial muscle, compared to the controls ( p < 0.01). Nerves repaired with CNTF had larger axon diameter, greater number of axons, and more advanced myelination ( p < 0.05). More HRP-labeled motor neurons were also found in the ventral horns of CNTF-treated animals. These results indicate that topical application of CNTF to the injury site potentiates motor nerve axonal regrowth and axon maturation during peripheral nerve regeneration.

Enhancement of rat sciatic nerve regeneration by fibronectin and laminin through a silicone chamber.

In this study, the authors examined the effects of fibronectin and laminin on sciatic nerve regeneration in rats. Sixty-eight Sprague-Dawley rats underwent bilateral sciatic nerve transections and silicone tubulizations, with a 10-mm gap between the proximal and distal nerve stumps. Thirty rats (n=30) received 10 microg of fibronectin injection into the right sciatic nerve chamber, while saline was injected into the left nerve chamber, serving as the control. Another 30 rats (n=30) were given 6 microg of laminin injection into the right nerve chambers and saline into the left chambers. At 1, 3, and 4 months postoperatively, electrophysiologic and histologic examinations, including nerve morphometry, were performed. Eight additional rats, receiving fibronectin (n=4) and laminin (n=4) injections, were used for horseradish peroxidase (HRP) tracing at 3 months postoperatively. Results from the study showed that fibronectin- and laminin-treated groups had significantly higher motor nerve conduction velocity and evoked muscle action potential amplitude of the anterior tibial muscle than the control group (p<0.01). Nerve diameter and the number of myelinated axons from the groups receiving fibronectin and laminin applications were greater than the controls (p<0.01). Also, a greater number of HRP-labeled motor neurons were found in the ventral horns and dorsal root ganglia of the fibronectin- and laminin-treatment groups compared to the controls. The authors conclude that local applications of fibronectin and laminin into the nerve chambers can significantly improve axonal regeneration and maturation of injured rat sciatic nerves.

Porcine small intestinal submucosa as a carrier for skin flap prefabrication.

The feasibility of porcine small intestinal submucosa (SIS) as a carrier in skin flap prefabrication was examined in this study. Thirty-eight rats were randomly divided into five groups. The saphenous vascular bundle was used as the vascular carrier. In group 1 (n = 8), an arteriovenous fistula was made by anastomosis of distal saphenous artery and vein. A SIS patch (1.5 x 2 cm2) was placed underneath the vascular bundle. In group 2 (n = 8), the vascular bundle was isolated and laid over the SIS patch. The distal saphenous vessels were ligated when the flap was raised. In group 3 (n = 8), an arteriovenous fistula was made without SIS implant. In group 4 (n = 8), the flap was raised with only the vascular bundle with the distal end ligated. After 2 weeks of maturation, the flap was raised with only the vascular bundle. In group 5 (n = 6), SIS was implanted and the flap including the SIS patch was raised and replaced without the vascular pedicles. The survival of the flaps and histology were evaluated at 5 days after flap replacement. The results showed that the average survival area in group 1 was 99% +/- 3% and the survival area in group 2 was 86% +/- 16%. The mean survival areas in group 3 and 4 were 60% +/- 9% and 25% +/- 10%, respectively. No flap survival was observed in the group 5. These were significantly lower than in groups 1 and 2 (p < 0.05, p < 0.01). Histology showed that SIS patch was incorporated into the adjacent connective tissue and increased amounts of neovascularization were seen between the collagenous sheets and dermis. In conclusion, this study demonstrated that porcine SIS can incorporate into the adjacent tissue and induce angiogenesis in flap prefabrication. This biomaterial can provide a scaffold for supporting and enhancing the survival of vascular prefabricated skin flap.

Effect of vascular endothelial growth factor on rat Achilles tendon healing.

This study evaluated the effect of exogenous vascular endothelial growth factor (VEGF) on tendon healing and regulation of other growth factors in a rat Achilles tendon model. Fifty Sprague-Dawley rats were used. In the experimental group, the left Achilles tendon was transected and repaired with the modified Kessler suture technique, and the right Achilles tendon was transected and repaired with resection of plantaris tendon. VEGF, 100 mul (50 mug/ml), was injected into each tendon at the repair site. The same surgical procedures were performed in the control group, with the same volume of saline injected into the repair sites. At intervals of 1, 2, and 4 weeks, the animals were killed and the tendons were harvested and evaluated for tensile strength (1, 2, and 4 weeks) and gene expression (postoperative day 4). At 1 week postoperatively, when plantaris tendon was preserved, the tensile strength of the repaired tendons with VEGF treatment (3.63 +/- 0.62 MPa) was significantly higher than the tensile strength of the repaired tendons with saline treatment (2.20 +/- 0.36 MPa). There was no difference in tensile strength between the two groups without the plantaris tendon support. At 2 weeks postoperatively, the tensile strength was 11.34 +/- 3.89 MPa in the group with VEGF treatment and plantaris tendon preservation, which was significantly higher than the tensile strength in the other groups. There was no significant difference in tensile strength among the groups at 4 weeks postoperatively. The gene expression showed that transforming growth factor-beta in the VEGF-treated tendon was up-regulated in the early stage of tendon healing, whereas expression of platelet-derived growth factor, basic fibroblast growth factor, and insulin-like growth factor-1 was not significantly different among the groups. In conclusion, administration of exogenous VEGF can significantly improve tensile strength early in the course of the rat Achilles tendon healing and was associated with increased expression of transforming growth factor-beta.

Effect of sodium diphenylhydantoin on skin wound healing in rats.

This study evaluated the effect of phenytoin (sodium diphenylhydantoin) on skin wound healing in a rat model. The study was divided into two parts. In part I, 20 mul of phenytoin (10 mg/ml) was subcutaneously injected into the 3-cm dorsal full-thickness incisional wounds of 14 rats on postoperative days 0, 3, and 6. Twelve rats that received saline injections were used as the controls. The skin samples were harvested and tested for tensile strength and histology. An additional 12 rats with the same incisional wounds were tested for chemokine gene expressions. In part II, 20 mul of phenytoin (10 mg/ml) was applied topically once a day on a 4 x 4 cm area of the open dorsal wounds of 10 rats. Saline was applied to the wounds of the 10 control group rats. The wounds were measured weekly. The results showed that the average tensile strength of the phenytoin-treated wound was 0.49 +/- 0.08 MPa compared with the control group at 0.02 +/- 0.01 MPa (p < 0.05). The density ratio of chemokine monocyte chemotactic protein (MCP-1) to beta-actin in the phenytoin-treated group was also significantly higher than in the control group (p < 0.05). Histologic analysis of the phenytoin group showed a large amount of fibroblast proliferation, collagen synthesis, and neovascularization. Phenytoin-treated wounds were also smaller at 1 to 6 weeks postoperatively than the control group wounds. The authors conclude that the administration of phenytoin can promote wound healing and significantly increase MCP-1 expression. Phenytoin-treated wounds showed significant increase in collagen deposition and neovascularization, which resulted in an increased wound tensile strength and accelerated healing of both open and closed wounds.