Renal Stone Formation and Development

A concise account of formation mechanisms of attached (papillary) and unattached renal stones is presented. Urinary conditions prevailing at least during the stone forming period are indicated. Ten main categories of renal stones, covering over 95% of all conceivable calculi, are distinguished based on their composition and structure. Aetiologic factors leading to stone formation of every category are specified and general outlines of recommended treatment procedures indicated.     

Cement migration after THR. A comparison of charnley elite and exeter femoral stems using RSA

Studies using roentgen stereophotogrammetric analysis (RSA) have shown that the femoral components of cemented total hip replacements (THR) migrate distally relative to the bone, but it is not clear whether this occurs at the cement-implant or the cement-bone interface or within the cement mantle. Our aim was to determine where this migration occurred, since this has important implications for the way in which implants function and fail. Using RSA we compared for two years the migration of the tip of the stem with that of the cement restrictor for two different designs of THR, the Exeter and Charnley Elite. We have assumed that if the cement restrictor migrates, then at least part of the cement mantle also migrates. Our results have shown that the Exeter migrates distally three times faster than the Charnley Elite and at different interfaces. With the Exeter migration was at the cement-implant interface whereas with the Charnley Elite there was migration at both the cement-bone and the cement-implant interfaces.     

Conventional CT signs in staging transitional cell tumors of the upper urinary tract

OBJECTIVES: To determine conventional computed tomography (CT) signs in the diagnosis and staging of upper urinary tract tumors (UUTTs). METHODS: Retrospective study was made of the CTs of 82 patients diagnosed with UUTTs. Nine CT signs were defined and compared with the pathology of the surgical specimen. A chi2 test was used for statistical analyses. RESULTS: We reviewed the CTs of 93 UUTTs in 82 patients, of which 36% were invasive and 12% had positive lymph nodes. Renal parenchymal invasion was found in 82% of high-grade and in 18% of low-grade tumors (p = 0.001). 94% of the tumors with signs of renal parenchymal invasion were invasive (p < 0.001), as well as 88% of those appearing as renal masses (p = 0.005), with a global sensitivity of 64% and specificity of 97%. The CT sensitivity and specificity of detecting infiltration of the ureter was 67 and 77%, respectively, and no sign was statistically significant. The detection of lymph node involvement had a sensitivity of 87.5% and a specificity of 98%. CONCLUSIONS: CT offers good sensitivity (87.5%) and specificity (98%) in the detection of lymph node involvement, and 64% sensitivity and 97% specificity for the detection of renal tumor invasion.     

Early diagnosis of stress fracture of the lumbar spine in athletes

Thirty-three athletes complaining of back pain of more than 1 months’ duration and with normal radiography of the lower spine were all studied by scintigraphy and in 24 of them with single photon emission computerized tomography. A stress fracture was considered present if localized increased uptake was seen at a vertebral level. Scintigraphy showed increased uptake in 17 of 33 patients and single photon emission computerized tomography in 16 of 24 patients.

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Résumé 33 athlèes se plaignant de lombalgies depuis plus d’un mois avec des radiographies normales de la colonne lombaire ont étéétudiés. Tous ont eu une scintigraphie, et 24 un scanner. A été retenu comme signe de fracture de fatigue, l’existence d’une augmentation de densitéà un niveau vertébral. La scintigraphie montrait une telle augmentation chez 17 des 33 patients et le scanner chez 16 des 24 patients. On conclut que même si la scintigraphie est normale, on ne peut pas rejeter le diagnostic de fracture de fatigue.

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Accepted: 22 October 1997     

The prognostic significance of DNA cytophotometry and proliferation index (Ki-67) in giant cell tumors of bone

We studied DNA ploidy by smear cytophotometry and proliferation activity by Ki-67 MIB immunohistochemistry in 69 primary and recurrent giant cell tumors (GCT) from 50 randomly selected patients. The obtained results were evaluated with comparisons made to the available clinical data. From the 46 primary tumors 63% showed diploidy and 37% aneuploidy. A significantly (P=0.026) higher recurrence rate (64%) was observed in aneuploid than in diploid tumors (31%). In the course of the recurrences, both the ratio of aneuploid tumors as well as the proliferation index of the tumors increased, though the degree of the latter was non-significant. Aneuploidy did not mean an unambiguous tendency towards malignant transformation; however, a close follow-up of recurrent aneuploid tumors, and wide excision of the recurrence instead of intralesional curettage are the recommended procedures. The DNA cytophotometry and proliferation index of GCTs – as compared to other histologic examinations – are of prognostic value in the evaluation of the recurrence potential of the GCTs.

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Résumé  Les auteurs ont examiné 1’anomalie chromosomique de DNA á 1’aide de cytophotometrie de frottis; et 1’activité de proliferation par le moyen de 1’immuno- histochimie Ki-67 MIB dans 69 tumeurs de cellules géantes de 50 patients choisis accidentellement. lls ont évalué les résultats en les comparant aux données cliniques disponibles. Parmi les 46 tumeurs primaires 63% ont manifesté un caractère diploide et 37% un caractère aneuploide. On a observé une proportion de recidive significativement plus élevée (P=0.026) dans les tumeurs aneuploides (64%) que dans les tumeurs diploides (31%). Au cours des récidives on a remarquè une augmentation tant dans la proportion des tumeurs aneuploides que dans 1’indice de proliferation mais en ce dernier 1’augmentation n’était pas significative. Le caractère aneuploide ne signifie pas forcément une tendance univoque á la transformation maligne cependant dans les tumeurs aneuploides récidivantes il est nécessaire de suivre la maladie avec beaucoup de soin et comme intervention chirurgicale on conseille une excision large au lieu du curettage intralésionel.

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Accepted: 20 October1999     

Intradural cervical chordoma. Case report

We describe a rare case of an intradural spinal chordoma. Only two cases have been previously reported and it is the second case diagnosed with MRI. A 65-year-old man presented with progressive disturbance of gait and weakness in the lower extremities. MRI revealed a intradural C6-C7 isointense mass, on T1- and T2-weighted images. The lesion enhanced after injection of gadolinium. The lesion was totally removed without difficulty by a C6-D1 laminectomy. Microscopic examination of the tumor revealed a chordoma. This is the third case in the literature of an intradural spinal chordoma. The appearance of this tumor with MRI may be similar to the chordomas of other locations.