The authors report on a prospective multicenter study with regard to the operative treatment of acute fractures and dislocations of the thoracolumbar spine (T10-L2). The study should analyze the operative methods currently used and determine the results in a large representative collective. This investigation was realized by the working group "spine" of the German Trauma Society. Between September 1994 and December 1996, 682 patients treated in 18 different traumatology centers in Germany and Austria were included. Part 2 describes the details of the operative methods and measured data in standard radiographs and CT scans of the spine. Of the patients, 448 (65.7%) were treated with posterior, 197 (28.9%) with combined posterior-anterior, and 37 (5.4%) with anterior surgery alone. In 72% of the posterior operations, the instrumentation was combined with transpedicular bone grafting. The combined procedures were performed as one-stage operations in 38.1%. A significantly longer average operative time (4:14 h) was noted in combined cases compared to the posterior (P < 0.001) or anterior (P < 0.05) procedures. The average blood loss was comparable in both posterior and anterior groups. During combined surgery the blood loss was significantly higher (P < 0.001; P < 0.05). The longest intraoperative fluoroscopy time (average 4:08 min) was noticed in posterior surgery with a significant difference compared to the anterior group. In almost every case a "Fixateur interne" (eight different types of internal fixators) was used for posterior stabilization. For anterior instrumentation, fixed angle implants (plate or rod systems) were mainly preferred (n = 22) compared to non-fixed angle plate systems (n = 12). A decompression of the spinal canal (indirect by reduction or direct by surgical means) was performed in 70.8% of the neurologically intact patients (Frankel/ASIA E) and in 82.6% of those with neurologic deficit (Frankel/ASIA grade A-D). An intraoperative myelography was added in 22% of all patients. The authors found a significant correlation between the amount of canal compromise in preoperative CT scans and the neurologic deficit in Frankel/ASIA grades. The wedge angle and sagittal index measured on lateral radiographs improved from -17.0 degrees and 0.63 (preoperative) to -6.3 degrees and 0.86 (postoperative). A significantly (P < 0.01) stronger deformity was noted preoperatively in the combined group compared to the posterior one. The segmental kyphosis angle improved by 11.3 degrees (8.8 degrees with inclusion of the two adjacent intervertebral disc spaces). A significantly better operative correction of the kyphotic deformity was found in the combined group. In 101 (14.8%) patients, intra- or postoperative complications were noticed, 41 (6.0%) required reoperation. There was no significant difference between the three treatment groups. Of the 2264 pedicle screws, 139 (6.1%) were found to be misplaced. This number included all screws, which were judged to be not placed in an optimal direction or location. In seve...

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Cylindric titanium rods with different surfaces were axially implanted into the femora of sheep. The three surfaces were grit-blasted titanium, plasma-sprayed titanium and plasma-sprayed hydroxyapatite (HA). After 2 months, a 2-cm segment of the femoral shaft was completely resected to load the implant, and the animals were allowed full weight-bearing for 9 months. Biomechanical and histological evaluation of the implants was undertaken 2 months after implantation and 9 months after the segmental resection. The mechanical testings of well-fixed implants were performed 9 months after segmental resection. Loosening of 45% of the titanium-coated implants was observed in the first 3 weeks, but thereafter, no further loosening occurred. The HA-coated implants remained entirely fixed for 3 weeks, but thereafter, a progressively increasing incidence of loosening up to 55% after 9 months of loading was detected as subsidence on X-radiographs. The maximum push-out strength of the titanium-coated implants was 4.9 MPa compared with 2.3 MPa for HA-coated ones. No significant mechanical interlock between the grit-blasted surface and bone was observed. The HA coating was found to be delaminated in all unstable implants, whereas the titanium coating remained completely intact. Morphometric analyses of well-fixed rods showed complete bony ingrowth onto the HA surface, whereas the contact area between the bone and the two titanium surfaces was less than 40%. Concerning clinical significance bony ingrowth with long-term mechanical interlock between the implant surface and the bone cannot be achieved by grit-blasting or HA-coating.(ABSTRACT TRUNCATED AT 250 WORDS)