[Quantification of postoperative vigilance by evoked potentials]. / Quantifizierung der postoperativen Vigilanz mittels evozierter Potentiale.

OBJECTIVE: Patients will be discharged from the postoperative recovery room mostly on subjective clinical assessment. In this study an approach to a more quantitative judgment of postoperative vigilance is made by recording the P300-latency and neuropsychological tests. METHODS: 22 adult patients undergoing a disc operation were examined. For induction of anesthesia thiopental (4-5 mg/kg), fentanyl (0.1 mg) and a musclerelaxant (atracurium 0.4 mg/kg or succinylcholine 1-2 mg/kg after precurarisation with atracurium 5 mg) were given. Anesthesia was then continued with enflurance (1.0-1.2 MAC) in a mixture of 67% nitrous oxide in oxygen. If postoperative analgesia was needed, piritramid was injected in boli à 3-6 mg. The P300 was acoustically stimulated with an oddball-paradigm and recorded at Fz and Cz. Afterwards the latencies were measured and compared with a vigilance score composed of clinical parameters and neuropsychological tests. Recordings were done preoperatively and every 30 minutes up to 2 hours postoperatively. A correlation between P300-latencies and vigilance score was made with the coefficient of Spearman. Comparison of pre- and postoperative values was managed by using Wilcoxon test for matched pairs with Bonferroni-correction. RESULTS: Immediately after operation, P300 was obtained only in 8 patients (36%). The latencies were delayed (394 +/- 35 ms versus 326 +/- 12 ms preoperatively). During follow-up patients recovered and 2 hours postoperatively only one patient had no P300. At the end of the examination period P300-latencies of most patients had not yet reached the preoperative levels. The vigilance score in parallel showed decreases immediately after the operation and increases later on. However there were discrepancies between P300 latencies and neuropsychological findings, in some cases possibly due to the sedative effects of postoperative analgetics. CONCLUSION: Recording of P300-latencies showed remarkable cognitive deficits because of subclinical anesthesia hangover even 2 hours after a routine inhalational anesthesia. It is a good quantifiable method for assessment of postoperative vigilance. In some cases P300-latency is a more sensitive parameter for vigilance phenomena than clinical and neuropsychological scores.

[Fibrous dysplasia versus osteofibrous dysplasia. Morphological, differential diagnostic and clinical aspects. Experiences from the Westfalen bone tumor registry]. / Fibröse Dysplasie versus osteofibröse Dysplasie. Morphologische, differentialdiagnostische und klinische Aspekte. Erfahrungen aus dem Knochengeschwulst-Register Westfalen.

Histologically, this lesion, which was first described by Campanacci, is characterized by an osteofibrous stroma replacing normal bone, showing trabeculae which, unlike in FD, are surrounded by a regular rim of prominent cubic osteoblasts, mature lamellar bone and zonal segmentation with newly formed trabeculae mostly in the cortical region. Radiologic features are eccentric, usually diaphyseally localized osteolytic lesions of the tibia with ground glass appearance. Differential diagnosis includes FD and adamantinoma. Just like OFD, the latter occurs almost exclusively in the tibia, its potential malignancy calling for a more radical therapeutical procedure. Being such a rare lesion, there are no clear guidelines regarding formal pathogenesis and therapy of adamantinoma in combination with osteofibrous stromal reaction. The mean age of the eleven patients with OFD was nine years, which is considerably lower than that of patients with FD (30 years). The lesions were found exclusively in the tibia. Surgical therapy is often followed by a recurrence of the tumor (in two cases in the present material), so it should be avoided, where possible. Thus, surgery should only be performed if complications are imminent, such as marked bone deformation or pseudoarthrosis. Unlike in FD, once bone maturation is completed, surgical treatment of OFD is not normally followed by recurrent disease. Thus, the prognosis of OFD with restricted surgical therapy is more favourable than that of FD, which frequently shows extensive skeletal involvement and recurrent disease even after many years. The more aggressive course of OFD reported by other authors must therefore be explained by too early surgical intervention, i.e. during bone maturation.