[(Modic) signal alterations of vertebral endplates and their correlation to a minimally invasive treatment of lumbar disc herniation using epidural injections]. / (Modic-)Signalveränderungen vertebraler Endplatten und ihr Bezug zu einer minimalinvasiven Injektionstherapie lumbaler Bandscheibenvorfälle.

PURPOSE: To study the influence of (Modic) signal alterations (SA) of the cartilage endplate (CEP) of vertebrae L3-S1 on the outcome of an in-patient minimally invasive treatment (MIT) using epidural injections on patients with lumbar disc herniation (LDH). MATERIALS AND METHODS: The MR images of 59 consecutive patients with LDH within segments L3/L4 - L5/S1 undergoing in-patient minimally invasive treatment with epidural injections were evaluated in a clinical study. The (Modic) signal alterations of the CEP were recorded using T1- and T2-weighted sagittal images. On the basis of the T2-weighted sagittal images, the extension and distribution of the SA were measured by dividing each CEP into 9 areas. The outcome of the MIT was recorded using the Oswestry Disability Index (ODI) before and after therapy and in a 3-month follow-up. Within a subgroup of patients (n = 35), the distribution and extension of the signal alterations were correlated with the development of the ODI. RESULTS: Segments with LDH showed significantly more (p < 0.001) SA of the CEP than segments without LDH. Although the extension of the SA was not dependent on sex, it did increase significantly with age (p = 0.017). The outcome after MIT did not depend on the sex and age of the patients nor on the type of LDH. The SA extension tended to have a negative correlation with the outcome after MIT after 3 months (p = 0.071). A significant negative correlation could be established between the SA extension in the central section of the upper endplate and the outcome after 3 months (p = 0.019). CONCLUSION: 1. Lumbar disc herniation is clearly associated with the prevalence of (Modic) signal alterations. 2. Extensive signal alterations tend to correlate with a negative outcome of an MIT using epidural injections. 3. Such SA in the central portion of the upper CEP correlate significantly with a negative treatment result. 4. The central portion of the upper CEP being extensively affected by (Modic) SA is a negative predictor for the success of a minimally invasive pain therapy.

[Distribution of MRI signal alterations of the cartilage endplate in pre-operated patients with special focus on recurrent lumbar disc herniation]. / Verteilungsmuster von (Modic-)Signalveränderungen an den vertebralen Endplatten voroperierter Patienten und ihr Bezug zu Rezidivvorfällen.

PURPOSE: To study the location of (Modic) MR signal alterations (SA) of the cartilage endplate (CEP) in pre- and non-operated segments L3-S1 with special focus on the presence of recurrent lumbar disc herniation (RLDH). MATERIALS AND METHODS: In a retrospective study the MR images of vertebrae L3-S1 of 65 consecutive patients with a history of microdiscectomy were evaluated. Of the 190 segments studied, 67 were pre-operated. These were divided into a group with recurrent lumbar disc herniation (RLDH) (n = 19) and a group without evidence of RLDH (n = 48). Non-operated segments (n = 123) were also considered as a separate group. In these three groups the prevalence of different Modic types was determined using the sag. T1- and T2-weighted images, and, in particular, the distribution of SA at the upper and lower CEP was examined by evaluating the sag. T2-weighted images. In order to achieve this, each CEP was divided into nine regions. RESULTS: Pre-operated segments showed significantly more frequent (p < 0.001) and more expansive (p < 0.001) SA than non-operated segments. Non-operated segments showed SA less frequently in the central region of both upper and lower CEP (p = 0.056 and p = 0.015, respectively). In operated segments without RLDH, the upper CEP had significantly more SA on the operation side than in the mid-sagittal and contra-lateral regions (p = 0.016, p = 0.037) and significantly more on the operation side of the lower CEP than in the contra-lateral region (p = 0.027). Operated segments with RLDH did not show an emphasis of SA on the operation side. In this group SA occurred significantly more often in the central and ventral mid-sagittal regions of the upper CEP than in the pre-operated segments without RLDH. CONCLUSION: 1. There are different patterns of signal alterations in the three groups. 2. The importance of the central region of the CEP for the integrity of the disc is strongly supported by the low incidence of signal alterations in this location in non-operated segments. 3. There are clear indications for the influence of the operation on the development and distribution of signal alterations. 4. In pre-operated segments signal alterations occurring in the central and ventral mid-sagittal regions of the upper CEP can be indicative of the development of RLDH.

Performance-based exposure control limits for pharmaceutical active ingredients.

For many years pharmaceutical companies have established employee exposure limits for the active ingredients used in their products. Historically these limits were derived using traditional risk assessment methods. Because the trend in the pharmaceutical industry is to identify and develop more selective drugs of increasing potency, and because of the difficulty in identifying no-effect levels for certain drugs, a new performance-based approach for setting limits was developed. This method involves assigning materials into one of five hazard categories according to their inherent toxicological and pharmacological properties. The criteria used to assign compounds into performance-based exposure control limit (PB-ECL) categories focus on the degree to which exposure impacts human health. These assignments dictate the level of containment required to assure employee safety that is achieved through the use of engineering controls and safe handling practices. Several matrices were developed to specify general design concepts and controls for unit operations in laboratory and manufacturing operations. Containment options range from conventional handling practices for low potency (PB-ECL Category 1) materials, to technologically advanced systems that result in essentially no open handling for potent or toxic (PB-ECL Category 3) materials, to state-of-the-art facilities employing closed processes and use of robotics for extremely potent (PB-ECL Category 5) materials.