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T Beutler

Publications and source records attributed to T Beutler.

5 recordsLinked to original sources
PubMed2005

Compliance of the L5-S1 spinal unit: a comparative study between an unconstrained and a partially constrained system.

A comparison between an unconstrained and a partially constrained system for in vitro biomechanical testing of the L5-S1 spinal unit was conducted. The objective was to compare the compliance and the coupling of the L5-S1 unit measured with an unconstrained and a partially constrained test for the three major physiological motions of the human spine. Very few studies have compared unconstrained and partially constrained testing systems using the same cadaveric functional spinal units (FSUs). Seven human L5-S1 units were therefore tested on both a pneumatic, unconstrained, and a servohydraulic, partially constrained system. Each FSU was tested along three motions: flexion-extension (FE), lateral bending (LB) and axial rotation (AR). The obtained kinematics on both systems is not equivalent, except for the FE case, where both motions are similar. The directions of coupled motions were similar for both tests, but their magnitudes were smaller in the partially constrained configuration. The use of a partially constrained system to characterize LB and AR of the lumbosacral FSU decreased significantly the measured stiffness of the segment. The unconstrained system is today's "gold standard" for the characterization of FSUs. The selected partially constrained method seems also to be an appropriate way to characterize FSUs for specific applications. Care should be taken using the latter method when the coupled motions are important.

Aged↗
PubMed2004

[Intraoperative three-dimensional navigation for pedicle screw placement].

The mobile SIREMOBIL Iso-C(3D) C-arm (Siemens, Erlangen, Germany) is the first device permitting intraoperative, three-dimensional representation of bone structures. A high-resolution, isotropic 3D data cube in the isocenter with sides of approximately 12 cm is calculated simultaneously. The SIREMOBIL Iso-C(3D) is linked to the navigation system. This makes it possible to transfer the generated 3D data directly to the linked navigation system without the need for surgeon-dependent registration. In this prospective clinical trial, we evaluated the accuracy of pedicle screw placement using this device. In 61 patients, a total of 302 pedicle screws were placed. Only in five cases (1.7%) were misplacements of > or =2 mm shown in postoperative control CT. The average fluoroscopy time was 1.28+/-0.56 min, and the average operative duration was 103.26+/-23.3 min. There were no postoperative neurological complications in any of the 30 patients. From these data, we conclude that Iso-C(3D) navigation is a very accurate method for the placement of pedicle screws.

Adolescent↗
PubMed2000

Technical details of sentinel lymph node mapping in colorectal cancer and its impact on staging.

BACKGROUND: Sentinel lymph node (SLN) mapping for melanoma and breast cancer has greatly enhanced the identification of micrometastases in many patients, thereby upstaging a subset of these patients. The purpose of this study was to see if SLN mapping technique could be used to identify SLNs in colorectal cancer and to assess its impact on pathological staging and treatment. METHODS: At the time of surgery, 1 ml of Lymphazurin 1% was injected subserosally around the tumor without injecting into the lumen. The first to fourth blue nodes identified were considered the SLNs, which have the highest probability to contain metastases. A standard oncological resection of the bowel was then performed. Multilevel microsections of the SLNs, including a detailed pathological examination of the entire specimen, was performed. RESULTS: SLN was successfully identified in 85 (98.8%) of 86 patients. In 85 patients, there were 1,367 (16 per patient) lymph nodes examined, of which 140 (1.6 per patient) were identified as SLNs. In 53 (95%) of 56, of whom the SLNs were without metastases (negative), all other non-SLNs also were negative. In 29 (34% of 85) patients, SLNs were positive for metastases; in 14 of the 29 patients, other non-SLNs also were positive in addition to the SLNs. In the other 15 of the 29 patients (18% of 85 patients), SLNs were the only site of metastases, and all other non-SLNs were negative. In 7 patients (8.2% of 85 patients), micrometastases were identified only in 1 or 2 of the 10 sections of a single SLN. In five of seven patients, such micrometastases were detected by hematoxylin and eosin staining and immunohistochemistry; in the other two patients, it was detected only by immunohistochemistry. In patients with negative SLNs, the rate of occurrence of micrometastases in non-SLNs was 5 (0.4%) of 1,184 lymph nodes. CONCLUSIONS: SLN mapping can be performed easily in colorectal cancer patients, with an accuracy of more than 95%. The identification of submicroscopic lymph node metastases by this technique may have upstaged these patients (18%) from stage I/II to stage III disease, who may then benefit from further adjuvant chemotherapy.

Chemotherapy, Adjuvant↗