Investigation of bone conditions for orthodontic anchorage plates in the anterior mandible.

OBJECTIVES: The clinical success of orthodontic anchorage plates depends on the stability of the miniscrews used for fixation. For good stability, the application site must provide bone of good quantity and quality. This study was performed to analyze bone quantity for orthodontic anchorage plates in the anterior mandible. PATIENTS AND METHODS: A total of 51 computed tomography (CT) scans of fully dentate patients (mean age 24.0±8.1 years; 27 men and 24 women) were evaluated. Measurements were taken to analyze the total orovestibular and vestibular cortical thickness of the mandibular jawbone at different anterior locations and levels. RESULTS: Vestibular cortical thickness is generally thinnest within the incisor area on the apex level. Its thickness increases in basal and distal directions. The total orovestibular thickness is also the least on the level of the anterior mandibular apices, becoming thicker toward more basal levels and the posterior teeth. CONCLUSION: We can reasonably assume that the stability of anchorage plates can be optimized by selecting a position well basal to the apices of the lower incisors, as this area offers enhanced cortical and total jawbone thickness.

Geometric accuracy of a newly developed cone-beam device for maxillofacial imaging.

OBJECTIVE: The aim of this study was to determine the geometric accuracy of scans obtained with a newly developed cone-beam computed tomography (CBCT) device in comparison with a multidetector row computed tomography (MDCT) scanner. STUDY DESIGN: Cone-beam scans were obtained with the preretail version of a newly developed compact size device with a scan volume of 15 x 15 x 15 cm. Conventional CT scans for comparison were performed with a 6-detector row CT scanner. To determine distance accuracy, 100 measurements were performed on radiopaque markers on a dry human skull. To determine volume accuracy, 25 measurements were carried out on a geometric phantom. Commercially available software was used for three-dimensional visualization and measurements on imaging data. RESULTS: Mean absolute measurement error (AME) for linear distances was 0.26 mm (+/-0.18 mm) for the CBCT device and 0.18 mm (+/-0.17 mm) for the MDCT device (P = .196 in paired t test). The average absolute percentage error (APE) was 0.98% (+/-0.73%) and 1.26% (+/-1.50%), respectively (P = .485 in paired t test). Linear regression analysis showed a positive correlation between AME and distance length (R = 0.628; P = .004) for CBCT-based measurements. Average AME in volume measurements was 1.78 mL (+/-0.99 mL) for the CBCT device and 1.23 mL (+/-0.93 mL) for the MDCT device. The average APE was 6.01% (+/-1.49%) and 4.42% (+/-1.99%), respectively. CONCLUSIONS: The results indicate that the evaluated cone-beam device provides satisfactory information about linear distances and volumes. Multidetector row computed tomography scans proved slightly more accurate in both measurement categories. The difference may be considered as not relevant for the majority of clinical applications.

Lymph node size and metastatic infiltration in non-small cell lung cancer.

BACKGROUND: Preoperative lymph node staging of lung cancer by CT relies on the premise that malignant lymph nodes are larger than benign ones. Lymph nodes > 1 cm in size are regarded as metastatic nodes. The surgical approach and potential application of neoadjuvant therapy regimens are dependent on this evaluation. PATIENTS AND METHODS: In a morphometric study, hilar and mediastinal lymph nodes from 256 patients with non-small cell lung cancer (NSCLC) were analyzed. The lymph nodes were counted, the largest diameter of each lymph node was measured, and each lymph node was analyzed for metastatic involvement by histopathologic examination. The frequency of metastatic involvement was calculated and correlated with lymph node size. Preoperative CT scans of 80 patients were retrospectively analyzed by a staff radiologist. Lymph node size was measured, and lymph nodes were evaluated due to radiologic criteria. The radiologic evaluation was compared to the histopathologic diagnosis. RESULTS: A total of 2,891 lymph nodes were present in the 256 specimens examined for this study. One hundred thirty-nine patients had a pN0 status, whereas 117 patients had lymph nodes that were positive for cancer. Two thousand four hundred eighty-six lymph nodes (86%) were tumor-free, while 405 (14%) showed metastatic involvement on histopathologic examination. The mean (+/- SD) diameter of the nonmetastatic lymph nodes was 7.05 +/- 3.75 mm, whereas infiltrated nodes had a diameter of 10.7 +/- 4.7 mm (p = 0.005). One thousand nine hundred fifty-three of the tumor-free lymph nodes (79%) and 170 of the metastatic lymph nodes (44%) were < 10 mm in diameter. Of 139 patients with no metastatic lymph node involvement, 101 (77%) had at least one lymph node that was > 10 mm in diameter. Of 127 patients with metastatic lymph node involvement, 12% had no lymph node that was < 10 mm. The independent radiologic evaluation of the CT scans of 80 patients yielded a sensitivity of 57.1% and a specificity of 80.6%. CONCLUSION: Lymph node size is not a reliable parameter for the evaluation of metastatic involvement in patients with NSCLC.

Transbrachial thrombolysis, PTA and stenting in the lower extremities.

We present an analysis of 37 interventions in the arteries of the lower limbs via a transbrachial arterial approach. Twenty-six patients (42-79 years) underwent 37 interventional procedures in the lower extremities (iliac n = 6, iliac + femoro-popliteal n = 1, femoro-popliteal n = 30) with a vascular approach via the brachial artery (33 left sided, 4 right sided, introducer sheath 4-7 F). The transbrachial approach was chosen to avoid puncture of femoral bypass graft material. Technical success could be achieved in 11/13 thrombolyses, 8/9 PTAs, 7/10 combinations of thrombolysis and percutaneous transluminar angioplasty (PTA) and in the placement of two stents. One patient suffered from periprocedural severe re-thrombosis due to insufficient anticoagulation during fibrinolysis, and twice thrombolysis was incomplete. One puncture-related false aneurysm of the brachial artery had to be corrected surgically. One transient ischemic attack (TIA) and four minor complications occurred. Transbrachial vascular approach for arterial interventions in iliac and femoro-popliteal pathologies is a reasonable alternative to the transaxillary access if transfemoral puncture has to be avoided. The technical success rate is comparable with the results of the transaxillary and transfemoral approach. To minimize, at least theoretically, the risk of cerebral complications, the left-sided approach should be preferred and intravenous heparin should be administered routinely.