Aggregatibacter aphrophilus ventriculitis following C1-C2 transarticular screw fixation

Objective Central nervous system (CNS) infections after cervical spine surgery are a rare but serious complication and may be caused by uncommon pathogens. We report the case of a 57-year-old male who developed slowly progressive mental confusion with headaches, increased daytime sleepiness and mild gait disturbance within the last 3 weeks. Six weeks prior to admission to our department, he underwent an atlantoaxial fusion by C1-C2 transarticular screw fixation for rheumatoid arthritis related C1-C2 multidirectional instability. Methods We analyzed clinical and neuroradiological findings. Results The findings were consistent with communicating hydrocephalus secondary to ventriculitis and the left C1-C2 screw was found to be misplaced with perforation of the dura. The situation was interpreted as implant related surgical site infection of the cerebrospinal fluid followed by ventriculitis and hydrocephalus. Bacterial broad range 16S rRNA gene PCR from the cerebrospinal fluid (CSF) followed by sequencing identified Aggregatibacter aphrophilus as the causative agent, while conventional cultures remained negative due to its fastidious growth. The patient was successfully treated with a lumbar drain and intravenous ceftriaxone. Conclusions To our knowledge, this is the first report of Aggregatibacter aphrophilus ventriculitis following C1-C2 transarticular screw fixation

Cross-Sectional Area of the Rotator Cuff Muscles in MRI - Is there Evidence for a Biomechanical Balanced Shoulder?

OBJECTIVE To provide in-vivo evidence for the common biomechanical concept of transverse and craniocaudal force couples in the shoulder that are yielded by both the rotator cuff muscles (RCM) and the deltoid and to quantitatively evaluate and correlate the cross-sectional areas (CSA) of the corresponding RCM as a surrogate marker for muscle strength using MRI. MATERIALS AND METHODS Fifty patients (mean age, 36 years; age range, 18-57 years; 41 male, 9 female) without rotator cuff tears were included in this retrospective study. Data were assessed by two readers. The CSA (mm2) of all rotator cuff muscles was measured on parasagittal T1-weighted FSE sequence at two different positions (at the established "y-position" and at a more medial slice in the presumably maximal CSA for each muscle, i.e., the "set position"). The CSA of the deltoid was measured on axial intermediate-weighted FSE sequences at three positions. CSA measurements were obtained using 1.5 Tesla MR-arthrographic shoulder. Pearson's correlation for the corresponding CSA of the force couple as well as was the intraclass correlation coefficient for the inter- and intra-reader agreement was calculated. RESULTS The mean CSA was 770 mm2 (±167) and 841 mm2 (±191) for the supraspinatus (in the y- and set-positions, respectively) and 984 mm2 (±241) and 1568 mm2 (±338) for the infraspinatus. The mean CSA was 446 mm2 (±129) and 438 mm2 (±128) for the teres minor (in the y- and set-positions, respectively) and 1953 mm2 (±553) and 2343 mm2 (±587) for the subscapularis. The three measurements of the deltoid revealed a CSA of 3063 mm2 (±839) for the upper edge, 3829 mm2 (±836) for the lower edge and 4069 mm2 (±937) for the middle of the glenoid. At the set position Pearson's correlation of the transverse force couple (subscapularis/infraspinatus) showed a moderate positive correlation of r = 0.583 (p<0.0001) and a strong correlation when the CSA of the teres minor was added to the infraspinatus CSA (r = 0.665, p = 0.0008) and a strong positive correlation of the craniocaudal force couple (supraspinatus/deltoid) that ranged from r = 0.565-0.698 (p<0.0001). Inter-reader agreement (ranged from 0.841 to 0.997, p = 0.0007) and intra-reader agreement were excellent (ranged from 0.863 to 0.999, p = 0.0006). CONCLUSION The significant correlation of the CSA of the RCM that form the transverse (subscapularis/infraspinatus-teres minor) and craniocaudal (supraspinatus/deltoid) force couple measured by MR-arthrography supports the biomechanical concept of a dynamically balanced shoulder in patients with an intact rotator cuff

Aggregatibacter aphrophilus ventriculitis following C1-C2 transarticular screw fixation

OBJECTIVE: Central nervous system (CNS) infections after cervical spine surgery are a rare but serious complication and may be caused by uncommon pathogens. We report the case of a 57-year-old male who developed slowly progressive mental confusion with headaches, increased daytime sleepiness and mild gait disturbance within the last 3 weeks. Six weeks prior to admission to our department, he underwent an atlantoaxial fusion by C1-C2 transarticular screw fixation for rheumatoid arthritis related C1-C2 multidirectional instability. METHODS: We analyzed clinical and neuroradiological findings. RESULTS: The findings were consistent with communicating hydrocephalus secondary to ventriculitis and the left C1-C2 screw was found to be misplaced with perforation of the dura. The situation was interpreted as implant related surgical site infection of the cerebrospinal fluid followed by ventriculitis and hydrocephalus. Bacterial broad range 16S rRNA gene PCR from the cerebrospinal fluid (CSF) followed by sequencing identified Aggregatibacter aphrophilus as the causative agent, while conventional cultures remained negative due to its fastidious growth. The patient was successfully treated with a lumbar drain and intravenous ceftriaxone. CONCLUSIONS: To our knowledge, this is the first report of Aggregatibacter aphrophilus ventriculitis following C1-C2 transarticular screw fixation

Measurement example deltoid.

<p>For the cross-sectional area (CSA) measurement of the deltoid muscle no reference in the literature existed. Thus, three measurement levels have been defined on axial three-dimensional gradient echo MR-arthrography sequences: CSA was measured at the upper- (2816 mm², top panel) and lower edge (4633 mm², bottom panel) and the middle of the glenoid (4002 mm², middle panel). Measurements were performed on the images of the same patient (see Figs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0157946#pone.0157946.g002" target="_blank">2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0157946#pone.0157946.g003" target="_blank">3</a>).</p

Flow chart of subject inclusion.

<p>RCT = rotator cuff tear, CPPD = Calcium pyrophosphate dihydrate deposition disease, RCM = rotator cuff muscles.</p

Anatomy of shoulder girdle and measurement example for “y-position”.

<p>Left panel shows a sagittal T1-weighted MR-arthrography image of the right shoulder of a thirty-five-year-old male, and depicts the anatomy of the shoulder girdle muscles on the level of the glenoid cavity: supraspinatus (A), infraspinatus (B), teres minor (C), subscapularis (D), deltoid (E), trapezius (F), triceps brachii (G) and teres major (H). Right panel illustrates one of the two positions where the cross-sectional area (CSA) of the rotator cuff muscles was measured: the most lateral slice, where the corpus scapulae and the spina scapulae had a Y-shaped appearance. CSA in this patient measured supraspinatus (793 mm², A), infraspinatus (969 mm², B), teres minor (515 mm², C) and subscapularis (1761 mm², D).</p

Correlation of muscle CSA measurements for transverse force couple.

<p>Table summarizes the results of the correlation of the cross-sectional area (CSA) measurements between the transverse force couple (Inf. = M. infraspinatus, Ter. = M. teres minor; Sub. = M. subscapularis). CSA measurements of the rotator cuff muscles were performed at two different positions: the “y-position” and the “set position”.</p

Correlation of muscle CSA measurements for craniocaudal force couple.

<p>Table summarizes the results of the correlation of the cross-sectional area (CSA) measurements between the craniocaudal force couple (Sup. = M. supraspinatus and the deltoid (Delt. sup. = M. deltoideus, at the upper edge of glenoid; Delt. mid. = M. deltoideus, at the middle of the glenoid; Delt. inf. = M. deltoideus, at the lower edge of glenoid). CSA measurements of the rotator cuff muscles were performed at two different positions: the “y-position” and the “set position”.</p

Distribution of cross-sectional area measurements.

<p>The scatterplot displays the distribution of the measured cross-sectional area (CSA) for each muscle and the respective standard deviation indicated by the margins of the bar. The y-axis describes the measured CSA in the unit mm², whereas the x-axis describes the various measured muscles.</p

Modic Type 1 Changes: Detection Performance of Fat-Suppressed Fluid-Sensitive MRI Sequences

Purpose To assess the performance of fat-suppressed fluid-sensitive MRI sequences compared to T1-weighted (T1w) / T2w sequences for the detection of Modic 1 end-plate changes on lumbar spine MRI. Materials and Methods Sagittal T1w, T2w, and fat-suppressed fluid-sensitive MRI images of 100 consecutive patients (consequently 500 vertebral segments; 52 female, mean age 74 ± 7.4 years; 48 male, mean age 71 ± 6.3 years) were retrospectively evaluated. We recorded the presence (yes/no) and extension (i. e., Likert-scale of height, volume, and end-plate extension) of Modic I changes in T1w/T2w sequences and compared the results to fat-suppressed fluid-sensitive sequences (McNemar/Wilcoxon-signed-rank test). Results Fat-suppressed fluid-sensitive sequences revealed significantly more Modic I changes compared to T1w/T2w sequences (156 vs. 93 segments, respectively; p < 0.001). The extension of Modic I changes in fat-suppressed fluid-sensitive sequences was significantly larger compared to T1w/T2w sequences (height: 2.53 ± 0.82 vs. 2.27 ± 0.79, volume: 2.35 ± 0.76 vs. 2.1 ± 0.65, end-plate: 2.46 ± 0.76 vs. 2.19 ± 0.81), (p < 0.05). Modic I changes that were only visible in fat-suppressed fluid-sensitive sequences but not in T1w/T2w sequences were significantly smaller compared to Modic I changes that were also visible in T1w/T2w sequences (p < 0.05). Conclusion In conclusion, fat-suppressed fluid-sensitive MRI sequences revealed significantly more Modic I end-plate changes and demonstrated a greater extent compared to standard T1w/T2w imaging. Key Points  · When the Modic classification was defined in 1988, T2w sequences were heavily T2-weighted and thus virtually fat-suppressed.. · Nowadays, the bright fat signal in T2w images masks edema-like changes.. · The conventional definition of Modic I changes is not fully applicable anymore.. · Fat-suppressed fluid-sensitive MRI sequences revealed more/greater extent of Modic I changes.. Citation Format · Finkenstaedt T, Del Grande F, Bolog N et al. Modic Type 1 Changes: Detection Performance of Fat-Suppressed Fluid-Sensitive MRI Sequences. Fortschr Röntgenstr 2017; DOI: 10.1055/s-0043-118130