Artikel
Missing quantification in decompressive craniectomies – methodological failures of craniotomy studies
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Veröffentlicht: | 2. Juni 2015 |
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Objective: In 1886 Marcotte published “De l'hemicraniectomie temporaire“. Kocher and Cushing introduced systematically DCs in trauma and tumor (1901-05), the last with poor results. In the 70-80ties the DCs in trauma and in the 90ties in MCA-/PICA-infarctions were redetected leading to a paradigma shift in patients >60 y. PubMed displays 13 DC-papers in the 80ties, 60 in the 90ties, 385 in 2000-09 and 700 more recently. Cushing described his diameter (7x8 cm) exactly, but later authors showed no or insufficient data ("large"). Most common is a desired diameter “at least 12 cm“, without control. Even actual studies (Destiny-2) scotomize these key-data.
Method: We analyzed the literature data on DC-diameters, reviewed the multiple methods of documentation and especially the resulting additional volumes.
Results: 1. Clinically reported DC-diameters range from 3-4 cm (Taylor 01) to >16 cm; 90% count the a.p.diameter only.
2. There are 4 methods of volume specification: Geometric calculation of 2.1. the removed bone (flat cylinder), 2.2. Planimetry. 2.3. Calculation of the boulging out-volume (boulging 10% of the DC-diameter), 2.4. 3-D-computer-measurements of a real skull based on 1-mm-CT-slices. All variants show widely-rangend (1:100) additional DC-volumes of 2-250 ml, dependent on diameter.
3. In one hospital with suggested diameter >12 cm three studies measured the DCs: Wirtz (97) reported areas of 59 - 128 cm2 (ø 84 cm2, which correspondences with diameters of 8.6 - 12.6 cm (ø 10.5 cm); Wagner (01) found ø 10.5 cm ± 2.8 cm (SD) and Hoffmann (13) 8.2 - 16.0 cm (ø 11.8 cm). The “desired” 12 cm-DC would produce 86 ml volume, a 14-cm-DC 150 ml. In contrast the de-facto-diameter 10.5 cm (mean) allows 50 ml and the worst case 8.2 cm 25 ml only, 17% of large DCs. Taylor (01) described even sham-OPs with >4 cm and 2 ml “decompression”. – An intra-op. lineal-check requires 10 s/diameter, a post-op CT/x-ray-analysis 10-60 min (Note: X-ray-distorsions; a sophisticated measurement is necessary).
Conclusions: In most craniectomy-studies measured diameters are missing. Due to the logarithmic increase of additional volume with the diameters the “dosage” / key-value of DC is not quantified. Poor results such in Destiny-2 could be caused by age, but also by too small craniectomies, which may be the rule further the exception.