Pressure sores and their treatment challenge CME/MOC. MOC-PS SM CME Article: Pressure Sores PREOPERATIVE ASSESSMENT.

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1 CME/MOC MOC-PS SM CME Article: Pressure Sores John Bauer, M.D. Linda G. Phillips, M.D. Galveston, Texas Learning Objectives: After studying this article, the participant should be able to: 1. Understand and describe the physiology of pressure sore development. 2. Understand and describe population risk factors. 3. Understand and describe examination and classification. 4. Understand and describe common surgical treatment algorithms. 5. Understand and describe strategies for prevention and postoperative recurrence. Summary: Pressure sores are ischemic damage to soft tissues resulting from unrelieved pressure, usually over a bony prominence. In both acute and chronic circumstances, a careful, structured multidisciplinary strategy is required from initial diagnosis to resolution. Mechanical issues, such as the relief of pressure, adequate surgical debridement, and flap coverage, are of little value if educational, nutritional, social, and resource-based issues are not in place. The authors discuss a range of topics, including etiology, physiology, classification, operative options, and strategies to prevent recurrence. The Maintenance of Certification module series is designed to help the clinician structure his or her study in specific areas appropriate to his or her clinical practice. This article is prepared to accompany practice-based assessment of preoperative assessment, anesthesia, surgical treatment plan, perioperative management, and outcomes. In this format, the clinician is invited to compare his or her methods of patient assessment and treatment, outcomes, and complications with authoritative, information-based references. This information base is then used for self-assessment and benchmarking in parts II and IV of the Maintenance of Certification process of the American Board of Plastic Surgery. This article is not intended to be an exhaustive treatise on the subject. Rather, it is designed to serve as a reference point for further in-depth study by review of the reference articles presented. (Plast. Reconstr. Surg. 121: 1, 2008.) Pressure sores and their treatment challenge many in the health care arena, but reconstruction of the soft-tissue defects is often relegated to the plastic surgeon. The causes are multifactorial; thus, before considering a surgical intervention, the surgeon must have a clear understanding of the physiology, classification, and cause of this ischemic injury and strategies to help prevent recurrence. PREOPERATIVE ASSESSMENT Basics Pressure sores are defined as soft-tissue injuries resulting from unrelieved pressure over a bony prominence. In other words, ischemia occurs when external pressure exceeds capillary pressure, which was shown by Landis in the 1930s From the Division of Plastic Surgery, University of Texas Medical Branch. Received for publication July 10, 2006; accepted February 6, Copyright 2007 by the American Society of Plastic Surgeons DOI: /01.prs to be between 12 and 32 mmhg. It is important though to understand that a number of factors play a role in the timing and severity of the injury. First, an inverse relationship exists between pressure and time to ulceration (Fig. 1). In a paraplegic pig model, soft-tissue injury occurred in only 2 hours at 500 mmhg, whereas at 100 mmhg, injury took 10 hours. 1 Furthermore, underlying soft tissues, especially muscle, are more susceptible to Disclosure: Neither of the authors has a financial affiliation with any of the products or services discussed in this article. The test for the MOC-PS aligned CME article Pressure Sores by Bauer and Phillips is available at ebusiness4/onlinecourse/courseinfo.aspx? Id

2 Plastic and Reconstructive Surgery January 2008 Fig. 1. Graph showing the pressure/time relationship. injury than skin, causing the tip-of-the-iceberg phenomenon, with the largest portion of the wound located deep, adjacent to the bone 1 (Fig. 2). Also, the presence of infection and edema can influence the wound environment and ultimately the extent of necrosis. Clinical investigations have shown a 100-fold increase in bacterial count in inoculated wounds subjected to pressure compared with controls. Impaired lymphatic drainage leading to edema, ischemia, and altered immune function has been implicated, and molecular evidence points Fig. 2. Drawing depicting the tip-of-the-iceberg phenomenon. to an imbalance between matrix metalloproteases and tissue inhibitors of metalloproteases. 2 Matrix metalloproteases, especially 1 and 9, are key to cell signaling and migration; whereas tissue inhibitors of metalloproteases, especially 1 and 2, bind to these proteases and presumably protect uninjured tissues. 3 In our spinal cord injured patients, the loss of sympathetic tone results in vasodilatation of denervated tissues, which further intensifies this problem. Finally, the areas of greatest pressure also vary with patient position. When supine, maximal pressures (40 to 60 mmhg) are at the heels, buttocks, and sacrum, 4 whereas in the sitting position, the area of maximal pressure is at the ischial tuberosities 4 (Figs. 3 and 4). Although a number of classifications exist, one of the most commonly used was proposed in 1989 by the National Pressure Sore Advisory Panel Consensus Development Conference (Table 1). From least to most severe, this system uses external signs such as erythema, blistering, and outright skin breakdown to determine the severity of necrosis. This four-stage system is a good basic guideline for the trained examiner, but as described, the external appearance often underestimates the extent of the injury, especially to the inexperienced eye. Consultations for evaluation of a pressure sore commonly come in the hospital setting. As might be predicted, those that develop acutely at admission occur most commonly in patients who are immobile or unconscious. These include patients with cardiovascular disease, acute neurologic disease, and orthopedic injuries. Many times, the plastic surgeon will be asked to see patients admitted to medical services with a preexisting pressure sore. In the general population, risk factors include age, male gender, sensory perception, 2

3 Volume 121, Number 1 Pressure Sores Fig. 3. Drawing depicting pressure and position. moisture, mobility, nutrition, and friction/shear. 5 The spinal cord injured population represents a significant subset of these patients, and risk factors specific to them include underweight, the use of pain medications, smoking, suicidal behavior, history of incarceration, and alcohol/drug use. 6 Before the Operating Room As alluded to above, a multitude of risk factors can put a candidate for pressure sore closure at risk for flap failure. Some of these can be controlled in the period leading up to surgery; others cannot. However, it must be remembered that the care and preparation of patients with pressure sores starts well before the operating room. Successful pressure sore coverage is multifactorial, but key components include adequate nutrition, resolution of infection, the preoperative/postoperative relief of pressure and, for cases of chronically nonambulatory patients, the control of spasm and contractures. The contribution of nutrition to wound healing has been well studied. Robson et al. showed that a serum albumin level greater than 2.0 g/dl will allow normal wound healing. This is often not the case with pressure sore patients, as they have been shown to be chronically catabolic in multiple studies. Optimizing both protein (1.5 to 3.0 g/kg/ day) and nonprotein (25 to 35 cal/kg/day) intake is key for replacing lean body mass. This can be accomplished with calorie counts and, if inadequate, can be addressed with either oral or even intravenous supplementation depending on the severity and the setting. Vitamins A and C are key to successful wound healing, as are supplements such as zinc, calcium, iron, and copper to maxi- 3

4 Plastic and Reconstructive Surgery January 2008 Fig. 4. Drawing depicting pressure and position. Table 1. National Pressure Sore Advisory Panel Consensus Development Conference Stage I II III IV Description Skin intact but reddened for 1 hr after relief of pressure Blister or other break in the dermis with or without infection Subcutaneous destruction into muscle with or without infection Involvement of bone or joint with or without infection mize soft-tissue and bone health. A good diet can provide all of these, but supplementation is inexpensive and easy. It should be emphasized that these supplements are only beneficial for those who are truly vitamin deficient, because no studies have shown that megadoses of these vitamins improve wound healing. It is imperative that, before a pressure sore is closed, the presence of infection has been investigated and eliminated. The removal of all nonviable tissue is the essential first step. After softtissue debridement, a specimen should be sent to the microbiology laboratory to assess not only the bacterial types and sensitivities, but also for quantitative culture. A result of more than 10 5 organisms per gram of tissue is diagnostic for invasive infection and is predictive of failure of surgical closure. Swab cultures are generally discouraged because they often represent only surface contaminants. Establishing the presence or absence of osteomyelitis is more controversial. The first and easiest step is plain radiography, which can be confirmatory but is not very sensitive. Nuclear scintigraphy has a high false-positive rate and is therefore not very helpful. Magnetic resonance imaging has been found to have higher sensitivity and specificity rates. 7 Debridement is the key here as well, although care must be taken, especially with ischial spines. Complete removal of one will shift the patient s weight bearing and almost surely lead to breakdown of the opposite side. Removal of both puts perineal strictures such as the urethra at risk with, the potential for development of urethrocutaneous fistulas. Finally, appropriate intravenous antibiotics for cellulitis or osteomyelitis, along with topicals such as silver sulfadiazine, mafenide acetate, and Dakin s solution, should be used as adjuncts to surgery in the process of clearing infection. Interestingly, it has been shown that Dakin s at a concentration of 0.025% is bactericidal but preserves essential resident cells such as fibroblasts. 8 All topicals should be used for a limited time after debridement to avoid delayed wound healing. The relief of pressure both preoperatively and postoperatively is the key to success, because healing will not occur in the presence of ischemia and/or necrosis. It is well known that relieving the pressure over a bony prominence for 5 minutes every 2 hours will allow adequate perfusion and prevent breakdown. 9 Patient, family, and medical staff education is paramount in this goal, and it must be performed in both supine and sitting positions. Adjuncts include foam, static flotation, and low air mattresses in the supine patient, and various gel and air cushion wheelchair pads. Involuntary muscular spasms contribute significantly to pressure sore development, especially in spinal cord injured patients. The damage to the soft tissue occurs primarily through shear forces, and these must be controlled before considering surgery. Spasms can be sufficiently severe to rip open a fresh surgical incision. Medical therapies include the use of agents such as Valium (Hoffmann-La Roche, Inc., Nutley, N.J.), baclofen, and dantrolene. More invasive methods such as nerve blocks, epidural stimulators, and baclofen pumps have been used with some success. Rhizotomy, or the interruption of spinal roots, has also been used and can be performed surgically or chemically with phenol. Recently, the use of an epidural pump has been suggested to control spasticity in the early postoperative period. 10 Finally, joint contractures develop especially in bedridden and debilitated patients. This tightening of the muscles and joint capsules limits range of motion and can make relieving pressure on bony prominences difficult for caretakers, limiting positioning. This is especially true in the lower extremities, where these contractures can 4

5 Volume 121, Number 1 Pressure Sores lead to pressure sores on the trochanters, knees, and ankles. If they cannot be relieved by therapy, tendon division can be considered, although flail extremities and difficult transfers can result. ANESTHESIA The challenge of anesthesia in patients with pressure sores centers on a number of issues: the presence or absence of sensation, airway protection, and anesthetic risks. The presence or absence of sensation in the tissues by pressure ulceration becomes an issue most often when sharp debridement is considered. The pain associated with the adequate removal of necrotic tissue in sensate patients makes bedside debridement impractical at best. In insensate patients, bedside debridement can be performed within reason, although the safety and extent often is more related to the control of hemorrhage. The airway becomes a challenge most often in the operating room. Because the majority of pressure sores are on the dorsal surface of the body, adequate debridement or flap closure often necessitates placing the patient in the prone position. Even in cases where the patient is completely insensate, general endotracheal anesthesia with appropriate corneal protection, and the use of prefabricated facial pads and mirrors is required in the event of vomiting, bronchospasm, or other anesthetic airway challenges. Finally, anesthetic risk and American Society of Anesthesiologists class are as much or more of a challenge in pressure sore patients than in other operative groups. Acute cardiovascular events including heart attacks and strokes constitute the majority of the acute iatrogenic pressure sores, just as many of our paraplegic patients have common chronic medical and substance abuse problems. This makes anesthesia, and especially general anesthesia, a serious risk. This risk can be further complicated in our spinal cord injured patients, where autonomic disturbances are common. Multiple studies have shown a range of systemic responses to maneuvers common in induction of anesthesia, such as positional change, endotracheal suctioning, and Valsalva maneuvers. Although the effects are complicated and may vary in acute and chronic settings, potential responses can range from bradycardia and hypotension in high spinal cord injuries with intact vagal responses and interrupted sympathetic tone, to tachycardia and significant increases in blood pressure in paraplegic patients, suggesting an altered catecholamine response. 11 It should also be remembered that the use of succinylcholine is contraindicated in spinal cord injured patients because of the lifetime risk of hyperkalemia caused by the up-regulation of acetylcholine receptors in denervated muscle tissue. 12 Thus, appropriate medical consultation and experienced anesthesia personnel are a must when operating on these patients. LOCATION OF OPERATION The general care of the pressure sore patient is a challenge and often requires the input of multiple medical specialties, which has led inevitably to the development of multidisciplinary clinics. This specialized care, along with advances in medical therapies such as enzymatic debridement, specialized mattresses, wheelchair cushions, and others, has made caring for these patients in the outpatient setting possible. However, if this type of therapy is inadequate to get a pressure sore to heal, and if the patient is a candidate for operative closure, a full hospitalization is almost always required. The operations themselves are often time consuming and may be associated with some blood loss and significant anesthetic challenges as described above. Postoperative vigilance including the proper bed, positioning, and nutrition, and controlling access to potentially harmful exposures to tobacco, alcohol, and drugs are also keys to preventing early complications and flap failures. OPERATING TIME Often, the greatest challenge in these operations is in moving and positioning these patients in the operating room. Usually, they must be anesthetized on their stretchers and then transferred prone to the operating room bed. They must then be transferred back to their bed onto their freshly closed flap for extubation, and finally turned again to a postoperative prone position. Making this an optimal and safe process requires a thoughtful preoperative strategy, choreographed planning with the operating room staff, and all of the appropriate equipment. Finally, as it relates to operating room time, pressure sore operations often have a significant open area, and jet lavage solutions are often used to lower bacterial counts. Therefore, these patients often run the risk of significant evaporative fluid loss and hypothermia; thus, an efficient, well-planned, well-executed operation is a must. SURGICAL TREATMENT PLAN When the challenges such as consistent pressure relief, adequate nutrition, eradication of 5

6 Plastic and Reconstructive Surgery January 2008 infection, complete debridement, and reliable patient and family education have been accomplished, consideration can be given to surgical closure. Many times, consultations for pressure sore closure are called with the reason given that they are getting worse. This is certainly not the time to consider closure, and in fact, consistent improvement in a pressure sore is one way to decide whether a patient is in fact a candidate for surgery. A number of strategies for closure have been attempted in the past and in general should be avoided. The temptation to perform a primary closure should be resisted even if the tissues seem to come together easily. By definition, a pressure sore has an absolute tissue deficiency, and simply pulling tissue together over a bony prominence will almost surely lead to tension and dehiscence. Skin grafting has been attempted with limited success because of the lack of bulk and poor durability in the face of the pressure and shearing forces. It is only successful in a patient where acute illness and immobility will be resolved. More successful strategies include the use of musculocutaneous and fasciocutaneous flaps, with each having its advantages. Flaps that include muscle have significant bulk and excellent blood supply. They therefore can be useful where a significant soft-tissue defect is present and also where a history of infection is a consideration. On the downside, muscle is susceptible to ischemic injury and is not a good choice in ambulatory patients, as sacrificing muscle may lead to functional impairments. Fasciocutaneous flaps are durable, maintain a good blood supply (especially if they are axial in design), are closer to the normal anatomical tissue arrangement, and are less susceptible to ischemia. Thus, they are especially useful in wounds of limited depth, as are many in the sacral area. However, they become less useful if significant filling of dead space is required. Most flap coverage strategies use pedicled flaps. Alternatively, a number of surgeons have advocated the use of free tissue transfer to address multiply recurrent pressure sores. 13 Common donors are the latissimus dorsi and serratus anterior muscles and fillet flaps taken from an amputated lower extremity. In many cases, the gluteal vessels are used as the recipients. 14 A number of authors from the 1970s to the present have reported the successful use of innervated free flaps using intercostal nerve bundles above the level of injury as recipients, 15 although this remains a challenging and less commonly used reconstructive strategy. Although pressure sores can appear nearly anywhere on the body where prolonged external pressure (e.g., bed rails, wheelchair footplates) is applied to soft tissue over bone, the areas that are most often encountered are ulcers over the ischia, sacrum, and trochanter. Although pressure leading to ischemia and tissue destruction is universal, the causes are different, as is the potential for good long-term outcome. Ischial pressure sores occur in patients who are sitting, and the vast majority are paraplegic. These wounds are commonly large and require a bulky flap to completely close the defect. There are a Fig. 5. A posterior thigh V-Y advancement flap. 6

7 Volume 121, Number 1 Pressure Sores Fig. 6. Postoperative recurrence in the patient shown in Figure 5. wide variety of flaps available to cover defects in this area, but consideration should be given to potential recurrence and also to the development of pressure sores in other nearby sites when a surgical ladder or algorithm is considered. Therefore, many surgeons choose to address the ischium with leg flaps first. These are reliable, can often be readvanced, and do not interfere with more superiorly based flaps if needed for the sacrum or trochanter. Small- to medium-sized defects can be addressed with posterior thigh flaps such as the biceps femoris alone when a patient is ambulatory, or with the addition of the semimembranosus and semitendinosus when the patient is not (Fig. 5). These have an excellent blood supply, are typically designed in a V-Y fashion, and again can often be readvanced in the case of recurrence (Fig. 6). Fasciocutaneous flaps preserve muscle, providing coverage for more shallower wounds. A posteromedial fasciocutaneous flap can also be elevated based on perforators from the gracilis or adductor magnus. 16 It has an excellent arc of rotation and does not contain muscle. The tensor fasciae lata flap can also be used and in fact can be designed as a sensate flap in some spinal cord injured patients with their injury below L3 (Fig. 7), 17 Fig. 7. Intraoperative and postoperative views depicting a tensor fasciae lata flap for the ischium. 7

8 Plastic and Reconstructive Surgery January 2008 but it is quite attenuated at the length needed to reach an ischial sore. The tissue over the gluteus maximus can be used and can contain either musculocutaneous or fasciocutaneous components. These are commonly designed as rotational flaps but can be designed as advancements flaps as well. In the case of ambulatory patients, the split inferior gluteal muscle flap can be used, which is based on the inferior gluteal artery and is less debilitating in hip flexion. Other reconstructive options have been described, including the laterally and anterolaterally based thigh fasciocutaneous flaps, and medially based flaps such as the gracilis musculocutaneous flap and the pedicled rectus abdominis myocutaneous flap. The pedicled rectus abdominis myocutaneous flap is based on the deep inferior epigastric artery and is very reliable but is not placed high on the reconstructive ladder because of its intrinsic importance in assisting truncal flexion, respiration, and Valsalva maneuvers for defecation and urination. 18 Sacral pressure sores develop from patients lying in supine position. If these are small and occur as a result of acute or short-term disability, they can often heal with conservative treatment. These can be exquisitely painful, and it is again tempting to attempt less invasive methods such as direct closure or skin grafting. Skin grafting may be successful for patients who will again become ambulatory and are sensate. However, the recurrence rates have been reported to be as high as 70 percent when using these methods in this location; so again, more reliable coverage should be considered. The mainstay coverage is the soft tissue overlying or including the gluteus maximus muscle, depending on the volume of tissue needed. Again, these are commonly designed as rotational flaps but can be advanced (Fig. 8). Both transverse and lumbosacral flaps based on the lumbar perforating vessels have also been described and can be ideal coverage, especially when limited bulk is needed, as is often the case in this area. Further useful options include the use of perforator island flaps such as the superior gluteal artery perforator as described by Lee et al. 19 Trochanteric defects result most often from patients lying in the lateral decubitus position. Unfortunately, this is often because the patients are debilitated and in many cases have hip and lower extremity contractures. This makes a reliable closure difficult and recurrence common. The method that has been used most commonly is the tensor fasciae lata flap. It can be raised as a muscle-only flap, or with skin and muscle. It can also be used as an island flap, and even a free Fig. 8. V-to-Y advancement flaps for the sacrum. tensor fasciae lata flap has been described. Again, this can be sensate in patients with spinal innervation above L3. Of note, tissue expansion has been attempted in closure of a number of settings to bring in sensate tissue. 20 A secondary option is the vastus lateralis flap, and a number of flaps based on the gluteus muscles have been described. Protocols for patients undergoing pressure sore flap reconstruction vary widely, but some principles are consistent. As is the case with all flap surgery, the goal in the operation is to raise a predictably vascularized flap and inset it with minimal tension. If available, quantitative cultures should be obtained for effective antibiotic coverage; and infected and necrotic soft tissue, bursae, and bone should be removed. The use of drains in these flaps is important, though how long is variable. Many surgeons wait until drainage has nearly ceased, and some wait longer. Care must be taken to protect the flap at the end of the operation, because most of these operations are performed with the patient prone and require flipping the patient for extubation and transfers. A non weight-bearing period postoperatively is required. Again, prone or lateral decubitus positioning is 8

9 Volume 121, Number 1 Pressure Sores CPT Codes Commonly Used in Decubitus Ulcer Surgery Procedure Without Ostectomy Sacrum Ischium Trochanter With Ostectomy Without Ostectomy With Ostectomy Without Ostectomy With Ostectomy Excision alone Excision with primary closure Excision with immediate skin flap Excision with immediate myocutaneous or fasciocutaneous flap Code Descriptor Muscle, myocutaneous, fasciocutaneous flap; trunk Muscle, myocutaneous, fasciocutaneous flap; lower extremity usually required, and low-air-loss beds are helpful to prevent the development of new pressure sores. This can be as long as several weeks, followed by limited sitting protocols for another several weeks. Because these protocols are hard to maintain, a monitored environment such as the hospital or skilled nursing facility is usually required. OUTCOMES Pressure sore patients are at risk for a multitude of complications, some directly and others indirectly associated with the pressure sore itself. Along with renal, pulmonary, cardiac, and hemorrhagic problems that occur in patients who develop pressure sores, infection is common in both soft tissue and bone. Pressure sores that are present for a prolonged period may erode into nearby hollow organs such as the urethra or rectum, or burrow into the hip joint and destroy the femoral head. Less common conditions such as heterotopic ossification 21 and even squamous cell carcinoma, better known as Marjolin s ulcer, have been described. As has been repeatedly pointed out, recurrence rates as high as 70 percent have been reported for patients undergoing treatment for pressure sores. This has led to a rapid expansion in the development of products designed to conservatively treat them and a decrease in surgical consultations. 22 Of importance, it should be pointed out that, even in these studies, the incidence of improvement using nonoperative measures alone was not demonstrated, and an actual increase in size was reported in many cases. Nevertheless, the effectiveness of conservative therapies such as the use of collagenase and papain/ urea-based enzymatic agents continues. Clinically, vacuum-assisted closure has shown tremendous clinical promise. It improves the pressure sore wound environment through the removal of fluid, control of bacterial colonization, and development of granulation tissue. 23 The future challenge will be to accumulate outcome data showing beneficial cost-to-benefit ratios. 24 Overall, these alternatives will not supplant the need for sound surgical judgment. CONCLUSIONS Prevention, in both the preoperative and the postoperative periods, plays an indispensable role and cannot be overemphasized. Along with good nutrition, control of other social and medical challenges is essential, including eliminating the use of tobacco, drugs, and alcohol; controlling medical conditions such as diabetes; using appropriate pressure-relieving devices such as low-air-loss mattresses and wheelchair cushions; and comprehensive patient/family education. When surgery becomes a viable option (see CPT coding table) and is carried out, a well-planned operation can be reversed with a single fall on transfer or a failure to consistently shift weight off areas prone to compression. Finally, as the development and the skill of multidisciplinary teams improve, better surgical outcomes can be anticipated in the treatment and prevention of pressure sores. John Bauer, M.D. Division of Plastic Surgery University of Texas Medical Branch 301 University Boulevard Galveston, Texas jdbauer@utmb.edu REFERENCES 1. Daniel, R. K., Wheatley, D., and Priest, D. Pressure sores and paraplegia: An experimental model. Ann. Plast. Surg. 15: 41, Nwomeh, B. C., Yager, D. R., and Cohen, I. K. Physiology of the chronic wound. Clin. Plast. Surg. 25: 341,

10 Plastic and Reconstructive Surgery January Ladwig, G. P., Robson, M. C., Liu, R., Kuhn, M. A., Muir, D. F., and Schultz, G. S. Ratios of activated matrix metalloproteinase-9 to tissue inhibitor of matrix metalloproteinase-1 in wound fluids are inversely correlated with healing of pressure ulcers. Wound Repair Regen. 10: 26, Lindan, O., Greenway, R. M., and Piazza, J. M. Pressure distribution on the surface of the human body. I. Evaluation in lying and sitting positions using a bed of springs and nails. Arch. Phys. Med. Rehabil. 46: 378, Fisher, A. R., Wells, G., and Harrison, M. B. Factors associated with pressure ulcers in adults in acute care hospitals. Adv. Skin Wound Care 17: 80, Krause, J. S., Vines, C. L., Farley, T. L., Sniezek, J., and Coker, J. An exploratory study of pressure ulcers after spinal cord injury: Relationship to protective behaviors and risk factors. Arch. Phys. Med. Rehabil. 82: 107, Healy, B., and Freedman, A. Infections. B.M.J. 332: 838, Heggers, J. P., Sazy, J. A., Stenberg, B. D., et al. Bactericidal and wound-healing properties of sodium hypochlorite solutions: The 1991 Lindberg Award. J. Burn Care Rehabil. 12: 420, Dinsdale, S. M. Decubitus ulcers: Role of pressure and friction in causation. Arch. Phys. Med. Rehabil. 55: 147, McCarthy, V., Lobay, G., and Matthey, P. W. Epidural anesthesia as a technique to control spasticity after surgery in a patient with spinal cord injury. Plast. Reconstr. Surg. 112: 1729, Yoo, K. Y., Jeong, S. W., Kim, S. J., Ha, I. H., and Lee, J. Cardiovascular responses to endotracheal intubation in patients with acute and chronic spinal cord injuries. Anesth. Analg. 97: 1162, Martyn, J. A., and Richtsfeld, M. Succinylcholine-induced hyperkalemia in acquired pathologic states: Etiologic factors and molecular mechanisms. Anesthesiology 104: 158, Hung, S. J., Chen, H. C., and Wei, F. C. Free flaps for reconstruction of the lower back and sacral area. Microsurgery 20: 72, Park, S., and Koh, K. S. Superior gluteal vessel as recipient for free flap reconstruction of lumbosacral defect. Plast. Reconstr. Surg. 101: 1842, Daniel, R. K., Terzis, J. K., and Cunningham, D. M. Sensory skin flaps for coverage of pressure sores in paraplegic patients: A preliminary report. Plast. Reconstr. Surg. 58: 317, Homma, 247 Selected readings. 17. Luscher, N. J., de Roche, R., Krupp, S., Kuhn, W., and Zach, G. A. The sensory tensor fasciae latae flap: A 9-year follow-up. Ann. Plast. Surg. 26: 306, Bunkis and Fudem, 253 Selected readings. 19. Lee, J. T., Hsiao, H. T., Tung, K. Y., and Ou, S. Y. Gluteal perforator flaps for coverage of pressure sores at various locations. Plast. Reconstr. Surg. 117: 2507, Neves, R. I., Kahler, S. H., Banducci, D. R., and Manders, E. K. Tissue expansion of sensate skin for pressure sores. Ann. Plast. Surg. 29: 433, Garland, D. E., and Orwin, J. F. Resection of heterotopic ossification in patients with spinal cord injuries. Clin. Orthop. Relat. Res. 242: 169, Isenberg, J. S., Ozuner, G., and Restifo, R. J. The natural history of pressure sores in a community hospital environment. Ann. Plast. Surg. 35: 361, Niezgoda, J. A., and Mendez-Eastman, S. The effective management of pressure ulcers. Adv. Skin Wound Care 19(Suppl. 1): 3, Nord, D. Cost-effectiveness in wound care (in German). Zentralbl. Chir. 131(Suppl. 1): S185,