Skin/Fat/Cartilage Grafts Flashcards
A 55-year-old woman undergoes composite resection of the right mandibular body and floor of the mouth. Closure with a fibular free flap is performed. A photograph is shown. Which of the following mechanisms best describes the healing process associated with vascularized bone transfers?
A) Endochondral ossification
B) Osteochondrosis
C) Osteoconduction
D) Osteogenesis
E) Osteoinduction
The correct response is Option D.
Osteogenesis is the formation of new bone by cells in a flap/graft that survive the transfer. This is the primary mechanism by which a vascularized bone graft heals. The pedicle keeps the bone alive so that primary bone healing can occur between the graft and recipient site. Osteoblasts from both locations participate in the formation of new bone at the interface between graft and native bone. Advantages of a vascularized bone graft include the ability to place the graft into a hostile environment such as an irradiated wound bed and immediate structural support with shortened time to bony union compared with nonvascularized cortical grafts.
Osteoinduction refers to the direct stimulation of mesenchymal cells at the recipient site by bone morphogenetic protein to differentiate into osteoprogenitor cells. This mechanism of action is associated with the healing of cancellous bone grafts and demineralized bone matrix.
Endochondral ossification is the process by which the cartilaginous soft callus covering a fracture is transformed into bone.
Osteochondrosis refers to a family of ossification disorders in children.
Osteoconduction (creeping substitution) is the primary method by which cortical bone grafts heal. During osteoconduction, cells and blood vessels from the recipient bed grow into the graft. The bone graft becomes a template for the deposition of new bone and the graft resorbs. Neovascularization is complete by 6 to 8 weeks, but ultimate strength of cortical grafts is not seen until 6 to 12 months, at which time the graft is comparable to a vascularized bone graft.
2018
A 55-year-old woman is scheduled to undergo autologous fat grafting to improve the upper inner quadrant aesthetic contour of the breasts. Six months ago, she underwent bilateral mastectomy and breast reconstruction with deep inferior epigastric perforator flap coverage. The patient does not have or desire breast implants. Which of the following percentage ranges most accurately describes the likelihood of fat graft survival in this patient?
A) 10%
B) 35%
C) 60%
D) 85%
The correct response is Option C.
Because of demonstration of the safety, efficacy, and improvements in the harvest and preparation of fat, autologous fat grafting or liposculpting is gaining popularity to adjust aesthetic breast contour irregularities after all forms of breast reconstruction. The most common complication of fat injection remains the resorption of the grafted fat.
Fat graft volume retention has been studied previously. Employing radiologic volumetric data analysis in fat grafting for cosmetic and reconstructive breast surgery demonstrates volume retention between 50 to 80% and this retention may be time and volume dependent.
Resorption of grafted fat may be attributable to apoptosis, a reduction in adipocyte volume after transplantation and survival, or a reduction in the fluid content of the grafted mixture.
2018
A 34-year-old man sustains deep second-degree burns to the forearm. He is brought to a local burn center. A skin graft is chosen as the coverage method. Which of the following management techniques offers the highest likelihood of skin graft survival in this patient?
A) Complete fascial excision
B) Early range of motion
C) Keeping the graft uncovered postoperatively
D) Placing a full-thickness graft
E) Placing a meshed graft
The correct response is Option E.
The principles of burn wound skin grafting dictate that first, a clean wound must be obtained. This is achieved through operative debridement and washout, to remove all necrotic eschar, and eliminate any possible source of bacteria or infection.
In most cases of second-degree burns, a complete fascial excision is not necessary, as this proceeds much deeper than the affected tissue. Instead, a tangential excision is used to remove burn eschar, in layers, until the necrotic tissue has been excised, and viable tissue remains at the base of the wound.
Following this, a split-thickness skin graft allows for greatest potential of graft survival. The use of a full-thickness graft will result in lower graft survival rates.
Meshing the skin graft prior to placement will improve survival, as it prevents accumulation of fluid or blood under the skin graft. Any collection of seroma or hematoma under the graft will prevent successful outcomes.
Placement of either a bolster dressing or a negative pressure (vacuum-assisted closure) dressing on the skin graft, will prevent mechanical shear forces, and improve graft survival rates. Thus, for the first 5 days after graft placement, any early motion or lack of dressing will result in greater risk of shear forces, and lower graft survival rates.
2018
A 52-year-old woman undergoes fat grafting of the upper right breast area to correct a contour indentation after implant reconstruction. Which of the following factors will most likely increase the success of fat grafting?
A) Abdominal donor site
B) Grafting soon after harvest
C) Rinsing the fat with Ringer’s lactate
D) Ultrasonic liposuction aspiration
E) Use of centrifuged fat
The correct response is Option B.
There is evidence that the longer fat is exposed at room temperature, the lower the adipocyte viability. There may be complete loss of stem cell viability by 4 hours at room temperature and 24 hours at 4°C (39°F).
There is no high-level evidence suggesting that centrifuging or rinsing fat increases viability. There is also no evidence for enhanced fat survival based on donor site, such as the abdomen, thigh, or arm. Use of local anesthesia does not appear to hinder graft survival. It does appear that less mechanical trauma with low-shear harvesting instruments is helpful. Ultrasonic liposuction is designed to rupture fat cells and would likely hinder graft survival.
Fat grafting is an increasingly common tool, although results appear to be operator-dependent based on wide ranges of success in published reports. There is no absolute agreed-upon method of measuring fat survival. Most studies use volumetric analysis with imaging. More future long-term studies are needed. At this time it appears that the commonality of successful results is delicate handling of the fat.
2018
A 43-year-old man undergoes wound closure with a split-thickness skin graft harvested from the left thigh. Which of the following skin appendages are the primary source of multipotent stem cells responsible for reepithelialization of the donor site?
A) Apocrine glands
B) Arrector pili
C) Eccrine glands
D) Hair follicles
E) Sebaceous glands
The correct response is Option D.
Hair follicles contain multipotent stem cells that are activated upon the start of a new hair cycle and upon wounding to provide cells for hair follicle and epidermal regeneration. In the hair follicle, stem cells reside in the bulge area. Bulge cells are relatively quiescent compared with other cells within the follicle but can be recruited during wound healing to support reepithelialization. Sebaceous, apocrine, and eccrine glands secrete fluids that are involved in lubricating, coating, or cooling the skin. Arrector pili are responsible for motility of cutaneous hair in response to tactile stimulation or low temperatures.
2018
A 23-year-old man comes to the office for post-traumatic cranial reconstruction 6 months after a motor vehicle collision. Physical examination shows a 5 × 4-cm full-thickness calvarial defect in the left parietal region. A titanium/hydroxyapatite cement cranioplasty reconstruction is planned. Which of the following mechanisms best describes the healing process associated with hydroxyapatite?
A) Endochondral ossification
B) Osteochondrosis
C) Osteoconduction
D) Osteogenesis
E) Osteoinduction
The correct response is Option C.
Restoration of craniofacial contour after infection, tumor resection, or trauma can be quite challenging. Autologous bone grafts have long been considered the gold standard because of their high likelihood of osseointegration/healing, and low risk of rejection or infection. Autologous bone grafts, however, have several drawbacks including unpredictable resorption, donor site morbidity, limited availability, prolonged operative times, and difficulty to contour. As a result, there has been an ongoing search for alternative means of reconstruction with alloplastic material.
The ideal bone substitute should be chemically inert, easily contoured, able to retain a stable shape over time, strong, resistant to infection or foreign body reaction, inexpensive, and capable of osseointegration and tissue ingrowth. Methylmethacrylate has been used frequently for calvarial reconstruction but suffers several drawbacks, including infection requiring removal of implant, plate fracture, lack of osseointegration, difficulty shaping after polymerization, and necrosis of surrounding tissue due to the exothermic nature of the curing process.
Among the most promising and well-tolerated alloplastic materials for craniofacial skeletal reconstruction are the calcium phosphate–based compounds. Hydroxyapatite [Ca(PO4)6(OH)2] forms the principal mineral component of bone and constitutes 60% of the calcified human skeleton. Calcium phosphate compounds are bioactive and capable of osteoconduction and osseointegration.
Osseointegration refers to the direct chemical bonding of an alloplast to the bony surface without an intervening fibrous tissue layer. During osteoconduction (creeping substitution), the alloplast acts as a nonviable scaffold for ingrowth of blood vessels and osteoprogenitor cells from the recipient site. Subsequently, the graft/alloplast is resorbed and replaced with new bone. This mechanism is also associated with the healing of cortical bone grafts.
Hydroxyapatite (HA) cement is a mixture of tetracalcium phosphate and dicalcium phosphate anhydrous, which react in an aqueous environment to form a paste that can be easily applied and sculpted to fit the surgical defect. HA cement sets isothermically, so there is no risk of thermal damage to the surrounding tissues. Additional benefits of HA include “off the shelf” ease of use, maintenance of volume over time, lack of radiologic scatter, and low incidence of infection.
Osteoinduction refers to the direct stimulation of mesenchymal cells at the recipient site by bone morphogenetic protein to differentiate into osteoprogenitor cells. This mechanism of action is associated with the healing of cancellous bone grafts and demineralized bone matrix. Endochondral ossification is the process by which the cartilaginous soft callus covering a fracture is transformed into bone. Osteogenesis is the process by which vascularized bone grafts heal. Viable osteocytes survive the transplantation process and produce new bone at the recipient site. Osteochondrosis refers to a family of ossification disorders in children.
2017
A 46-year-old man with type 1 diabetes mellitus is evaluated for an infected foot ulcer. After adequate surgical debridement, a collagen bilayer matrix is used for coverage. Which of the following clinical factors represents the greatest risk for failure of reconstruction?
A) Anatomic location
B) Exposed bone
C) Exposed tendon
D) Polymicrobial infection
E) Type 1 diabetes mellitus
The correct response is Option D.
Collagen bilayer matrices have become an important option in the reconstructive ladder for lower extremity wounds. Studies have demonstrated the ability of these dermal regeneration templates to neovascularize and heal into pliable, durable coverage in an attempt to achieve stable wound healing and maintain limb length. Many of these studies were performed in the setting of diabetic wounds with exposed bone or tendon, thus each of these settings does not represent a contraindication. Adequate debridement, including clearance of any polymicrobial infection, is one of the keys to successful reconstruction.
2017
A 47-year-old man undergoes split-thickness autografting for the treatment of a forearm burn. Which of the following donor site dressings is most appropriate to optimize wound healing?
A) Alginate covered with occlusive dressing for 7 days
B) Moist gauze covered with occlusive dressing for 7 days
C) Petrolatum gauze covered with occlusive dressing for 2 days, then left open to air
D) Petrolatum gauze left open to air
E) Xenograft left open to air
The correct response is Option A.
To optimize wound healing, a moist wound-healing environment has been shown to be superior to a dry wound-healing environment. Studies on split-thickness skin graft donor sites have not been very well designed, but many studies suggest that a moist dressing is better than a dry dressing, and several review papers support this concept. Although leaving petrolatum gauze open to air is very common and may be the most practical option in certain circumstances, it does not optimize wound healing compared with a moist dressing. The only options listed that provide a moist environment for the duration required for early reepithelialization are gauze covered with occlusive dressing and alginate dressings. Gauze covered with occlusive dressing would not work well, because conventional gauze would stick to the wound and be very difficult to remove without causing significant tissue injury. Alginate dressings are emerging as an excellent option for split-thickness skin graft donor site wounds. They are adaptable, absorptive, nonadhesive, antibacterial, and provide a moist environment for wound healing.
2017
Which of the following best describes the immediate mechanism of skin graft survival following placement onto the recipient wound bed?
A) Dermal contraction
B) Encapsulation
C) Inosculation
D) Revascularization
E) Serum imbibition
The correct response is Option E.
Serum imbibition describes the earliest stage of skin graft healing. Immediately after placement onto the wound, the graft becomes edematous and may increase its mass up to 30 to 40%. Plasma leaks from recipient bed capillaries and venules and fills the space between the wound bed and the graft. Fibrinogen within the plasma settles out and forms a fibrin bond, which helps anchor the graft to the wound. The graft passively absorbs nutrients from the underlying serum by diffusion during the first 48 hours. Metabolism within the graft becomes anaerobic and the pH level falls to 6.8. The metabolic demands of the graft also fall, with ATP levels falling 70% and glucose levels falling 80%.
Revascularization and inosculation describe the second stage of skin graft healing. These processes began shortly after graft placement, but it takes approximately 4 to 5 days for the graft to become vascularized, with maximal flow developing by day 29. Revascularization refers to direct ingrowth of new blood vessels into the graft from the underlying wound bed. Inosculation describes a process by which blood vessels from the underlying wound bed connect with existing vessels in the skin graft. More recent evidence suggests that both of these processes play a role in the development of vascularization within the skin graft: existing vasculature within the skin graft undergoes some level of degeneration. However, the acellular basal lamina persists and provides a conduit for the ingrowth of a new vascular tree from the host wound bed.
Primary contraction of a skin graft occurs immediately after harvest and is due to the recoil of elastic fibers within the dermis. Grafts with a larger amount of included dermis (e.g., full-thickness grafts) have greater primary contraction. Secondary contraction refers to contraction after the wound heals. This process is mediated by myofibroblasts and occurs more frequently in grafts with a thinner dermal component (e.g., split-thickness grafts). A larger dermal component appears to suppress proliferation of myofibroblasts within the wound. Encapsulation refers to the development of a fibrous scar capsule around a foreign device such as a breast implant.
2017
A 65-year-old man comes to the office because of a 6 × 8-cm open wound on the forearm. The wound currently has healthy granulation tissue and does not appear infected. Which of the following is an advantage of split-thickness skin grafting over full-thickness skin grafting in this patient?
A) Less metabolic demand required from wound bed
B) Less secondary contraction from elastin fibers
C) More primary contraction from myofibroblasts
D) Occurrence of inosculation before plasmatic imbibition
E) Presence of intact skin appendages within graft
The correct response is Option A.
Split-thickness skin grafts require less metabolic demand from the wound bed compared with full-thickness skin grafts. In situations where the wound bed may not supply adequate nutrient diffusion through the graft, a full-thickness graft may develop superficial epidermolysis.
Skin graft viability is initially based on plasmatic imbibition from the serous exudate of the wound, followed by inosculation and angiogenesis. After graft take, remodeling and scar maturation occur. Primary contracture of a graft is from elastin fibers in the dermis, whereas secondary contracture is from myofibroblast activity.
Split-thickness grafts contain epidermis and a variable amount of dermis compared with full-thickness grafts, which, by definition, contain both epidermis and the entire dermal layer. Full-thickness grafts contain intact skin appendages, whereas split-thickness grafts do not; this allows the donor site for split-thickness grafts to reepithelialize. Split-thickness grafts therefore undergo less primary and more secondary contraction.
2016
A 9-year-old boy with unilateral cleft lip and palate undergoes alveolar bone grafting with a cancellous iliac bone graft. Which of the following best describes the mechanism of bone healing?
A) Endochondral ossification
B) Osteochondrosis
C) Osteoconduction
D) Osteogenesis
E) Osteoinduction
The correct response is Option E.
Osteoinduction refers to the direct stimulation of mesenchymal cells at the recipient site by bone morphogenetic protein to differentiate into osteoprogenitor cells. This mechanism of action is associated with the healing of cancellous bone grafts and demineralized bone matrix.
Osteoconduction (creeping substitution) is the primary method by which cortical bone grafts heal. During osteoconduction, cells and blood vessels from the recipient bed grow into the graft. The bone graft becomes a template for the deposition of new bone and the graft resorbs. Neovascularization is complete by 6 to 8 weeks, but ultimate strength of cortical grafts is not seen until 6 to 12 months, at which time the graft is comparable to a vascularized bone graft.
Osteogenesis is the formation of new bone by cells in a flap/graft that survive the transfer. This is the primary mechanism by which a vascularized bone graft heals. The pedicle keeps the bone alive so that primary bone healing can occur between the graft and recipient site. Osteoblasts from both locations participate in the formation of new bone at the interface between graft and native bone. Advantages of a vascularized bone graft include the ability to place the graft into a hostile environment such as an irradiated wound bed and immediate structural support with shortened time to bony union compared with nonvascularized cortical grafts.
Osteochondrosis refers to a family of ossification disorders in children. Endochondral ossification is the process by which the cartilaginous soft callus covering a fracture is transformed into bone.
2016
A 64-year-old woman is evaluated because of the aged appearance of the dorsal surfaces of the hands. Physical examination of the hands shows lipodystrophy. Autologous fat grafting is planned to improve the cosmetic appearance. Which of the following maneuvers is most likely to decrease the risk of fat necrosis and improve fat graft viability?
A) Placement of fat grafts in small aliquots
B) Postoperative prevention of pressure on grafted regions
C) Preparation of fat grafts with centrifugation
D) Use of ultrasound-assisted liposuction for fat graft harvest
The correct response is Option A.
The results of fat grafting are dependent upon the surgeon’s experience and technique. Strategies to increase the take of the fat graft and decrease fat necrosis include atraumatic harvest techniques. Placement of the graft in multiple small aliquots increases the availability for vascularity, and creating a lattice-like framework when depositing the grafts avoids large-volume deposits. Placement of the grafts in a few large-volume deposits is avoided to minimize fat necrosis and creation of fatty oil cysts. Centrifugation has mixed results in fat grafting.
2016
A 22-year-old woman is evaluated in the emergency department because of necrotizing fasciitis of the right upper extremity. BMI is 35 kg/m2. After adequate debridement, the entire extensor and flexor compartments are open with exposed tendon. A photograph is shown. Which of the following is the most appropriate initial method of reconstruction?
A) Anterolateral thigh free flap
B) Bilaminate neodermis
C) Full-thickness skin grafts
D) Pedicled abdominal flap
E) Split-thickness skin grafts
The correct response is Option B.
Although a bilaminate neodermis (Integra) artificial skin substitute has been traditionally used in the acute management of burns, there have been many successful reports incorporating its use in general reconstructive plastic surgery. Integra is a bioengineered dermal substitute consisting of a bilayer membrane system. The dermal replacement layer is composed of a cross-linked bovine tendon collagen-glycosaminoglycan (chondroitin-6-sulfate) matrix coated on one side with a synthetic polysiloxane polymer (silicone) layer. This layer functions as an epidermis to control moisture loss from the wound. The collagen matrix serves as a scaffold for ingrowth of fibroblasts, macrophages, lymphocytes, and capillaries and is ultimately replaced by host tissue. Integra “take” mirrors skin graft “take” and follows the sequence of 1) imbibition, 2) fibroblast migration, 3) neovascularization, and 4) maturation.
As the host tissue infiltrates the dermal layer, the collagen layer is biointegrated with the wound to form a vascular neodermis capable of accepting a split-thickness skin graft after a period of approximately 4 weeks. Proper patient selection and careful monitoring for infection or hematoma accumulation are crucial in this time period. After approximately 4 weeks, the silicone layer is removed and a thin (0.008- to 0.010-inch) skin graft can be applied.
Advantages of Integra use include improved cosmesis, diminished scar contracture or development of hypertrophic scar, off-the-shelf availability in large quantities, increased elasticity, and the ability to use thinner skin grafts with subsequent improvement in donor-site morbidity, scar, and time to heal. Other cited advantages include commensurate growth of the grafted tissue in children, potential avoidance of a microsurgical procedure, and placement over tendons with no significant reduction in tendon mobility. The disadvantages of Integra include its high cost, steep learning curve, need for at least two stages with subsequent increased time to final closure, potential for infection under the silicone layer, and lack of adnexal structures with patient concerns of skin dryness.
In this patient, use of Integra with delayed thin split-thickness skin grafts at 4 weeks will give the best outcome in terms of cosmesis and function. A photograph is shown. Split-thickness skin grafts are not a good option in this location because of the risk of graft loss with tendon exposure due to lack of viable paratenon and the risk of secondary contracture at the wrist and elbow. Full-thickness skin grafts would diminish the risk of secondary contracture but harvesting enough tissue to cover the entire arm would be impossible using the inguinal region as a donor site. Full-thickness grafts also require a healthier wound bed for optimal graft “take” and are not likely to heal over exposed tendons.
Free tissue transfer is an excellent technique for resurfacing the forearm, but in this patient, the thigh donor site would be difficult secondary to tissue thickness and the need for an extremely large flap. A better choice could be the scapular or parascapular donor site, perhaps in combination with a preliminary tissue expansion of that location. Obtaining enough tissue would be difficult. Banking the forearm in the abdomen would be less desirable as well, given her obesity and the need for a large surface area.
2016
A 30-year-old man requires bone grafting for repair of a severe nasal deformity after a bicycle collision. Which of the following is the optimal rib donor site for ease of exposure and limited morbidity?
A) First
B) Third
C) Fourth
D) Seventh
E) Eleventh
The correct response is Option D.
Ribs five through seven are commonly described as the ideal sites for harvesting because of ease of access and ample bone material compared with the more cephalic or caudal ribs. The seventh rib has the added advantage of being situated over the abdominal cavity, reducing the risk for pneumothorax during harvest. Ribs five and six are also suitable, and may hide better in the inframammary crease of women.
Ribs may be harvested either whole or split depending on the amount of material needed. If a whole-rib graft is required, as long as multiple adjacent ribs are not removed, morbidity is limited. Split-rib harvest offers the advantage of eventual bone regrowth, and the area can be harvested for bone grafting again in the future if needed. The eleventh rib provides a wide expanse of medial cartilage for harvest, although it is not an ideal bone donor site.
Rib grafts offer both cortical and cancellous bone material. The cortical bone is rigid and provides immediate structural support, though final incorporation and strengthening occur over many months. A well-vascularized wound bed is required for bone healing and incorporation. A split-rib inset provides the cancellous bone surface, which is more rapidly revasculuarized. If an entire bone is needed for grafting, then a vascularized bone graft or flap with microvascular anastomosis would be better suited.
2016
A 25-year-old woman is scheduled for correction of a deformity of the nasal dorsum caused by previous nasal trauma as a child. Autologous rib cartilage grafting of the dorsum is planned to correct the deformity. Which of the following complications is most likely in this patient?
A) Extrusion
B) Necrosis
C) Ossification
D) Resorption
E) Warping
The correct response is Option E.
The most consistent complication of cartilage grafting is the propensity to change shape or warp over time. This may be due to the presence of perichondrium or the nonuniform composition of the matrix that can affect the shape when it is placed.
Pure cartilage grafts tend to maintain shape, but grafts with an intact perichondrial layer can curl significantly and lead to unpredictable results. During septal graft harvest, care must be taken to elevate mucoperichondrial flaps in the proper plane. Likewise, auricular or costal cartilage grafts must be harvested in a subperichondrial plane. Removal of the perichondrium and softer outer cartilage layer leaves the more rigid cartilage core, which maintains shape more predictably.
Extrusion, necrosis, ossification, and resorption are not known to be affected by the presence or absence of the perichondrial layer. Fresh autologous grafts easily survive transplantation procedures and do not appear to resorb over time.
Autologous cartilage from septum, concha, or rib is considered the ideal graft material. These grafts have very low risk for infection or extrusion compared with an allograft. Cartilage grafts are tolerated well by nasal tissue.
2016
A 58-year-old man is referred by an orthopedic surgeon after undergoing open reduction and internal fixation of a fracture of the ankle after falling down stairs. The repair is complicated by wound dehiscence with 2 × 2 cm of exposed tibialis anterior tendon without paratenon. A photograph is shown. After debridement of healthy tissue, reconstruction is performed using bilaminate neodermis with placement of a standard bolster dressing. At which of the following times relative to placement of the bilaminate neodermis should split-thickness skin grafting be performed?
A) At the same time
B) 1 week after
C) 2 weeks after
D) 4 weeks after
E) 6 weeks after
The correct response is Option D.
Integra is a bilaminate neodermal material that consists of an outer silicone sheet and an inner layer of bovine collagen and glycosaminoglycan (derived from shark cartilage), which acts as a scaffold for regeneration. Specifically, there is migration of host fibroblasts into the matrix, which subsequently proliferate and form collagen. Additionally, there is migration of endothelial cells that form a vascular network within the neodermis, which can subsequently act as a foundation to support staged split-thickness skin grafting, at which time the silicone outer layer is removed and a thin (usually 6–8/1000”) split-thickness autograft is applied. The success, or “take,” of the skin graft depends on whether the neodermis is vascularized sufficiently to maintain graft viability. A 2001 study by Moiemen et al. demonstrated clinically and histologically that this process takes 4 weeks on average, without the use of topical negative pressure.
A follow-up article from 2004 suggests this process can be accelerated from 4 weeks to an average of 7.25 days if topical negative pressure is used. Further follow-up studies based on the clinical appearance of the bilaminate neodermal matrix have suggested reduction in complication rates, improved patient tolerance, and enhanced and accelerated neovascularization with the use of topical negative pressure wound therapy. However, a study published in 2010 looking histologically at various time points could not demonstrate that topical negative pressure wound therapy accelerates neovascularization as verified by the presence of histologically patent vascular channels. The authors found that the median percentage of the template depth that demonstrated canalized channels was 0%, 20%, 61%, and 80% for days 7, 14, 21, and 28, respectively.
Because this question pertains to the use of bilaminate neodermal matrix with the use of a standard bolster dressing and not negative pressure wound therapy, most existing evidence indicates that the most appropriate timing is 4 weeks after placement of the bilaminate neodermis.
2016
