Clinical manifestations of radiation injury can be split into acute and chronic. Acute effects include erythema, dry desquamation (which occurs at moderate radiation doses) and moist desquamation (which occurs with ablation on most dangerous skin cancers). Since the skin cancer is treated, the basal epidermal layer becomes denuded, resulting in serous oozing characteristic of the final condition. The result is that as radiation injury becomes chronic, dermal and adnexal structures are affected.
Hypo- and hyperpigmentation, thickening from the dermis and loss of sebaceous and sweat gland function result in dessicated, poorly vascularized tissue that is tough to take care of. These changes are irreversible. Finally, necrosis and even cancer can arise from a chronic damage of a radiated target. Considering these changes, any nonhealing ulcer that arises within a radiated field must always be biopsied to rule out neoplasia.
Given these characteristics from the chronic radiation wound, its propensity to dessicate and its inability to create the normal inflammatory response, meticulous local wound care is essential. Maintaining a moist wound bed to avoid bacterial intrusion is essential. In early phases of damage, patient education is crucial: one must be informed of avoidance of sun exposure, alcohol-based emollients, cosmetic-based agents and trauma to the radiated area. Gentle cleansing with normal saline or mild soap solutions is recommended.
Moist desquamation requires copious irrigation with dilute peroxide or normal saline, then light application of Silvadene. When dealing with dry desquamation, one must make amends for the loss of moisture secondary to sebaceous/sweat gland destruction. Several hydrophilic preparations (e.g., hydrogels) and antipruritic agents have been used with good effect.
Beyond topical therapy, an irradiated wound must be clean all the time. Manual irrigation with pressurized water helps you to clean off surface exudates. A helpful suggestion to patients is by using multiple forceful showers for big wounds, or the irrigating pulse of the dental cleaner for small wounds. In wounds where surface cleansing doesn't suffice, meticulous sharp debridement, using the overall goal of reducing or eliminating bacterial counts by clearance of devascularized tissue, is crucial for wound closure.
Debridement shouldn't only be aggressive, but frequent; the presence of small quantities of devascularized tissue can result in progressive bacterial overgrowth and subsequent necrosis. The "poorly" vascularized tissues of tendon, bone and cartilage are the most troublesome to deal with, because of the difficulty in maintaining a moist environment and also the prevention of new tissue dessication.
The incidence of chronic radiation problems for the intestine, occurring in 2-5% of patients who receive abdominal or pelvic radiation, is on the rise. Its manifestations, including abdominal strictures, hemorrhage, perforation and fistulae result in complex abdominal wall defects. Most frequently, small bowel adherent to and glued by scar into the pelvis receives an inordinately high local dose of radiation. This happens after treatment for rectal, bladder and gynecologic malignancies. Surgical goals in these cases consist of damage control, return of intestinal continuity and reconstruction of the abdominal wall.
Generally a multidisciplinary approach, involving nutritional, colorectal, oncological, and reconstructive specialists, is mandatory. When perforation or fistulization is present, the first objective is to decrease the amount of fluid flowing over the fistula point. This can be achieved with simple measures such as bowel rest, or need a more aggressive approach, such as proximal diversion.
A second objective would be to decrease local inflammation from the soft tissues with adequate drainage of feculent material, gentle surface cleansing and antibiotics. A surgical repair could be contemplated once the wound is less acute and inflamed, when nutrition continues to be optimized, so when the anatomy is thoroughly understood.
Even then, the complication rate could be formidable. Anastomosis of diseased and even normal bowel segments within the irradiated field is fraught with morbidity and potential mortality. Along wrinkles, research has demonstrated a leak rate of 36% and mortality as high as 21% in patients who underwent resection and anastomosis in cases of radiation enteritis.
The problem inherent in such scenarios is pinpointing precisely what segment of bowel is diseased and what is normal. Neither intraoperative frozen section nor Doppler survey of bowel segments have been beneficial in reducing complications. Out of this experience, it makes probably the most clinical sense to widely resect the bowel in the area of the fistula and to locate the brand new anastomosis far from the radiation field.
At our institution, several principles are widely-used to guide treatment of the abdominal wall. The debridement of all inflamed tissue is crucial, so that in no case should the success from the procedure depend on the healing of fibrotic, scarred tissue without pulsatile blood circulation. After debridement, two independent decisions must be designed to guide intraoperative planning: first, what's the company's abdominal wall, and second, what is the company's soft tissue (skin) cover? Integrity of the abdominal wall is obtained while using separation of parts process of midline defects.
For nonmidline defects, our tissue of choice is really a sheet of autogenous fascia lata. There's interest in the use of new biologic agents for example Alloderm and Surgisys in these situations as well to avoid the donor site morbidity of fascia lata harvest. These sheets of tissue are sewn to the undersurface from the intact abdominal wall using horizontal mattress sutures with as much overlap to good tissue as possible.
When the skin can be mobilized and closed (either in the midline or over the fascia lata laterally), the procedure is finished. In certain instances, myocutaneous TFL and rectus abdominis flaps are utilized to provide full-thickness vascularized coverage to the abdominal wall reconstruction.
The radiated pelvis is its own subject, as radiated bowel loops often may become adherent and fistulize the perineum. The abdominal wall reconstruction is usually less important as keeping bowel from the pelvis after surgery. Following a wide bowel resection and site from the new anastomosis away from the radiated field, a flap is chosen to separate the intraabdominal contents from the pelvis inflammation which can 't be easily debrided. In these cases, a rectus flap having a skin paddle based obliquely in the periumbilical perforators and angled toward the tip from the scapula is raised and dropped to the pelvis.
This oblique rectus abdominis myocutaneous flap (ORAM) is preferable to the standard VRAM flap, because this technique significantly decreases the quantity of muscle harvested, while still adequately filling the pelvic dead space. The fat under the skin does not atrophy with time, and so the bowel loops don't have the opportunity to slowly reenter the pelvis.
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