Pressure necrosis

Research based on Wolff s law of bone transformation has resulted in some other important observations. Fluctuating loads, such as those that occur in walking, are better for bone than consistentiy appUed loads, such as weight gain. However, if the effective appUed load becomes extreme, pressure necrosis, ie, bone death, occurs. Pressure necrosis is a significant concern in hip arthroplasty. Necrosis means the localized death of living tissue. Undue pressure on living cells causes death. Some total hip replacement failures are the direct result of pressure necrosis. 

A 75 year old man was examined on a routine visit 1 month after being disabled by a stroke. He was very immobile and in bed. He complained of a painful heel, which on examination was inflamed and with a small necrotic centre. A pressure sore was diagnosed and suitable measures taken to manage this. A week later there were further lesions on the other foot but this time on the dorsum of the foot and lower leg. These were not easily explained by pressure necrosis, indeed a closer examination suggested a vasculitis. The cause for this was frusemide which had been prescribed for a mild heart failure apparent at the time of the stroke. It is very easy to accept the obvious without careful examination. 

Surface Properties of lUDs. Most lUDs currently in use cause only minimum changes in the uterine endometrium (19). Excessive menstrual bleeding, intermenstrual spotting, and bleeding between menstrual periods have been noted as sources of annoyance, and they constitute a major reason for removal of lUDs. Such bleeding is probably secondary to local hyperemia, edema, pressure necrosis, and sometimes endometritis (20). After lUDs are inserted into the uterus, some patients complain of pain and low backache, but pain is a minor reason for discontinuing intrauterine contraception. 

Yell RR Am ] Emerg Med 8, 246 (1980) Brodin MD +, j Cutan Pathol 7, 326 Diaphoresis Fixed eruption Hypersensitivity Pressure necrosis... 

The gastrostomy tube is fixed using the external stabilizer, which comes with the set. One should not place too much pressure on the abdominal wall when fixing the stabilizer, because pressure necrosis of gastric mucosa can occur. The post-procedural approach is identical to the push technique. 

Pacemaker pocket erosion continues to be a problem (Fig. 4.104). This is best avoided by creating a pacemaker pocket that has maximum optimal tissue thickness. Occasionally, in extremely asthenic individuals, subpectorahs major muscle pulse generator placement should be considered to afford optimal tissue thickness. Patients can also present with preerosion secondary to pressure necrosis of the overlying tissue. Such situations represent a quasiemergency if one is to avoid complete erosion and wound infection. The patient should be reoperated, the old pocket abandoned, and new pacemaker pocket created away from the involved site. Sutton and Bourgeois incidence of pacemaker pocket complications are shown in Table 4.25 (17). 

Fig. 19.1 Photograph of pressure necrosis. The subcutaneous tissue over the lateral aspect of the pulse generator is thinned due to the resorbtion of the adipose tissue while the overlying skin is molded to the pulse generator and developing a blue-red discoloration. The area is also tender.

Malignant fistulas between the esophagus and the respiratory system are a serious complication of esophageal cancer and occur in 5%-15% of patients (Martini et al. 1970 Little et al. 1984 Duranceau and Jamieson 1984). They may arise spontaneously as a result of tumor invasion or they may be caused by radiation therapy, surgery, pressure necrosis caused by a previously placed plastic or metallic stent, or laser therapy (Burt et al. 1991 Duranceau and Jamieson 1984 Saxon et al. 1994 Cwikiel et al. 1998). The onset of symptoms of aspiration is a devastating development for patients aheady debilitated by malnutrition caused by the dysphagia. Patients are often unable to swallow their own saliva without aspirating. 

Because of the delivery of the calcium ion to the deeper tissues remains one of the major problems in the treatment, another method is the development of arterial infusion of calcium solutions to the extremities 50 mL of 4 % calcium gluconate solution is infused over 4 h and repeated at intervals until the patient is pain-free. Between one and three cycles may be needed but sometimes more. This kind of treatment gives good results but may have some complications as nerve palsy (due to the position of immobilization or caused by hematomas from multiple attempts at catheter placement). Because of these complications, despite the results without risk of local toxicity, pressure necrosis, or fingernail removal, its use would be considered in severe hand HF injuries. 

Most complications include infection, and leakage of air and bowel content. It is therefore important to keep the wound clean and well dressed. Leakage is prevented by daily checking of the external bolster for loosening. Conversely, too tight fixation may cause pressure necrosis and dislocation of the internal bolster into the gastric wall. 

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