PubMed · 3782201
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W Petty. 1986. Osteonecrosis.. https://pubmed.ncbi.nlm.nih.gov/3782201/
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Because of the controversy that exists about therapy for the Pipkin fracture, the treatment and results of 117 fractures of the femoral head were reviewed and re-evaluated at least 1 year after the trauma had taken place. The cases were taken from eight publications in the literature from 1983 to 1995. The lesions in this collection comprised 35% (n = 41) type I, 40% (n = 47) type II, 10% (n = 12) type III and 15% (n = 17) type IV fractures classified after the Pipkin system. Seventy-four percent of patients (n = 87) were operated on; only type I lesions were treated conservatively in 42%, thus more often than average. There were 57 complications with equally frequent head necroses (14.5%) and severe coxarthritis. Coxarthritis was doubled after conservative treatment versus operation (23% vs. 13%). There was no difference in respect to head necrosis. Postoperatively, 18 (14%) periarticular ossifications were registered. Forty-one (75%) of 55 Pipkin I and II fractures had an at least "good" outcome; the portion of conservative treatment was higher than operative treatment (88% vs 69%). Still these results have to be seen with respect to the use of treating simple lesions primarily conservatively with the minimum of 6 weeks of traction therapy, thus counting the latter patients in this group. According to the literature, we think that if there are no vital contraindications, all Pipkin fractures should be treated operatively (early emergency operation) by reattaching bigger fragments and extracting smaller fragments in Pipkin I and II fractures, trying to save the heads in young, active patients with Pipkin III fractures in contrast to primary endoprosthesis in elderly patients with coxarthrosis with Pipkin IV fractures (unstable and displaced fractures of the acetabulum).
BACKGROUND AND PURPOSE: Comparing some isocentric coplanar techniques for conformal irradiation of prostate and seminal vesicles. MATERIALS AND METHODS: Five conformal techniques have been considered: (A) a 3-fields technique with an antero-posterior (AP) field and two lateral (LAT-LAT) 30 degrees wedged fields; (B) a 3-fields technique with an AP field and two oblique posterior (OBL) 15 degrees wedged fields with relative weights of 0.8, 1 and 1, respectively; (C) a 4-fields technique (AP-PA and LAT-LAT); (D) a 6-fields technique (LAT-LAT and four OBL at gantry angles 45 degrees, 135 degrees, 235 degrees and 315 degrees) with all the fields having the same weight; (E) the same 6-fields technique with lateral fields double-weighted with respect to the oblique fields. The conformal plans have been simulated on 12 consecutive patients (stages B and C) by using our 3D treatment planning system (Cadplan 2.7). The contours of the rectum, the bladder and the left femoral head were outlined together with the clinical target volume (CTV) which included the prostate and the seminal vesicles. A margin of 10 mm was added to define the planning target volume (PTV) through automatic volume expansion. Then a 7 mm margin between the PTV and block edges was added to take the beam penumbra into account. Dose distributions were normalised to the isocentre and the reference dose was considered to be 95% of the isocentre dose. Dose-volume histograms and dose statistics of the rectum, the bladder and the left femoral head were collected for all plans. For the rectum and the bladder the mean dose (Dm) and the fraction of volume receiving a dose higher than the reference dose (V95) were compared. For the femoral head, the mean dose together with the fraction of volume receiving a dose higher than 50% (V50) were compared. RESULTS: Differences among the techniques have been found for all three considered organs at risk. When considering the rectum, technique A is better than the others both when considering Dm and V95 (P = 0.002), while technique D is the worst when considering Dm (P < 0.002) and is also worse than techniques A, E (P = 0.002) and C (P = 0.003) when considering V95. Technique E is the best when considering the bladder mean dose (P = 0.002 against A and D, P < 0.01 against B and C) and technique C is the worst (P < 0.012). No relevant differences were found for the bladder V95. In the femoral heads, techniques A and E are worse than B, C and D (P < 0.003) when considering Dm and V50. Moreover, techniques B and D are better than C (P < 0.004) when considering V50. CONCLUSIONS: There is no technique that is absolutely better than the others. Technique A gives the best sparing of the rectum; the bladder is better spared with technique E. These results are reached with a worse sparing of the femoral heads which should be carefully taken into account.
Historically, four perpendicular treatment fields or bilateral arcs have been used in the treatment of prostate cancer. "New techniques" including four conformal fields, seven conformal fields, 120 degrees bilateral conformal coplanar, and non-coplanar arc'ed beam arrangements, are replacing the "older" approaches. These techniques result in a reduction in doses to adjacent critical structures while covering the clinical target volume (CTV). This study, analyzes the impact of random or systematic isocenter displacement errors (IDE) associated with the delivery of radiotherapy, using the best of these "newer techniques". Dose Volume Histograms (DVH) were used to evaluate the dose to the prostate and surrounding normal tissues with 0.3 cm, 0.5 cm and 0.8 cm IDE. It was determined that IDE associated with fixed coplanar treatment techniques could reduced the prescribed dose to the prostate by 0-8%, the coplanar are technique reduced the prescribed prostate dose by 3-10%, and the noncoplanar conformal arc technique could lower the prescribed prostate dose by 0-5%. Predictably, 0.3 cm IDE found in the posterior and inferior direction increase the dose to the rectum by 5-12% and lowered the dose to the bladder by 4-8%. Errors in the superior and anterior direction increased the dose to the bladder by 4-8% and decreased the dose to the rectum by 8-10%. Errors in the right to left direction slightly increased the dose to the ipsilateral femoral head. Doses to the rectum and bladder associated with 0.5 cm and 0.8 cm IDE are significantly larger. The frequency and magnitude of IDE must be accounted for before higher doses can be delivered safety. Recognizing the impact of IDE on our ability to deliver the prescribed dose to the planning target volumes (PTV) could incorporate the impact of IDE during the planning process.