Anxiety dissociates dorsal and ventral medial prefrontal cortex functional connectivity with the amygdala at rest

Anxiety is linked to compromised interactions between the amygdala and the dorsal and ventral medial prefrontal cortex (mPFC). While numerous task-based neuroimaging studies show that anxiety levels predict amygdala-mPFC connectivity and response magnitude, here we tested the hypothesis that anxiety would predict functional connectivity between these brain regions even during rest. Resting-state functional magnetic resonance imaging scans and self-reported measures of anxiety were acquired from healthy subjects. At rest, individuals with high anxiety were characterized by negatively correlated amygdala-ventral mPFC functional connectivity, while low anxious subjects showed positively correlated activity. Further, high anxious subjects showed amygdala-dorsal mPFC activity that was uncorrelated, while low anxious subjects showed negatively correlated activity. These data show that amygdala-mPFC connectivity at rest indexes normal individual differences in anxiety.     

Metastatic adrenocortical oncocytoma: a case report

With only 51 cases reported in the literature to date, adrenocortical oncocytoma is an exceedingly rare pathological variant of adrenal neoplasms. The first case of metastatic adrenocortical oncocytoma is reported along with an update of the literature. A role for radiotherapy in the palliative setting is demonstrated.     

Screw orientation and plate type (variable- vs. fixed-angle) effect strength of fixation for in vitro biomechanical testing of the Synthes CSLP

BACKGROUND CONTEXT: Two common justifications for orienting cervical screws in an angled direction are to increase pullout strength and to allow use of longer screws. This concept is widely taught and has guided implant design. Fixed- versus variable-angle systems may offer strength advantages. Despite these teachings, there is a paucity of supporting biomechanical evidence. The purpose of our study is to test the influence of screw orientation and plate design on the maximum screw pullout force. PURPOSE: This study evaluates the effect of screw orientation and plate type (fixed- vs. variable-angle) on screw pullout strength. STUDY DESIGN: Anterior cervical plates of both a fixed- and variable-angle CSLP, were tested for peak pullout strength in a direct plate pullout model using polyurethane foam bone, which models osteoporotic bone. METHODS: Self-tapping, locking screws (4.0x14mm and 4.0x16mm) were used. Screws were oriented in the fixed-angle plate in the standard fashion. In the variable plate, screws were instrumented in three different orientations. Biomechanical testing was performed on an Instron DynaMight 8841 servohydraulic testing machine, measuring maximum pullout force under a displacement-controlled pullout rate of 1mm/min. Five samples were tested per group. RESULTS: When all screws were placed 90 degrees to the plate, there was a significantly increased peak pullout strength (412.8+/-22.2N) compared with when all screws were placed 12 degrees "up and in" (376.2+/-24.3N, p less than or equal to .03). When the 90 degrees construct was reproduced using 14-mm screws and compared with 16-mm screws oriented 12 degrees "all up and in," there was still significantly higher pullout strength with the all 90 degrees construct (434.2+/-28.7N vs. 376.2+/-24.3N, p less than or equal to .009). The fixed-angle plate had a significantly decreased peak pullout strength (288.2+/-15.7N) compared with the variable-angle plate (416.6+/-12.6N) (p less than .00001) when the screws were placed in the same orientation. Overall, the variable-angle plate, regardless of the orientation of screws, had a significantly greater pullout strength than the fixed-angle plate (p less than .001). CONCLUSIONS: In this system, a variable-angle plate has greater pullout strength than a fixed-angle plate, regardless of the orientation of screws. With the variable-angle plate, a construct of all screws 12 degrees "up and in" is the weakest configuration. We found that with the 90 degrees construct, both 16- and 14-mm screws performed significantly better than 16-mm convergent screws. These findings are remarkable because they contradict the current doctrine. This may be a function of plate-dependent factors and should not be applied universally to all plate systems. Further study of screw orientation in additional plating systems is warranted.     

A cluster of nocardial brain abscesses

BACKGROUND: Nocardia species are aerobic Gram-positive bacteria that are ubiquitous in the environment. Infection usually occurs through inhalation or direct cutaneous inoculation of the organism. It has been reported that infection is more common in warm, dry climates. Cerebral nocardiosis is an uncommon clinical entity, representing only 2% of all cerebral abscesses. It is an illness associated with significant morbidity and mortality. CASE DESCRIPTIONS: We report 4 cases of nocardial brain abscesses presenting to TCH, Australia, within a 1-year period. All 4 cases occurred in men without any significant underlying immunocompromise. In 3 of the cases, the diagnosis was only established after craniotomy. All cases were given prolonged antimicrobial therapy. After more than 8 months of follow-up, there have been no deaths or treatment failures. There has been only one other case of nocardial brain abscess at TCH over the past 15 years. We review the current literature on cerebral nocardiosis. CONCLUSION: Nocardial brain abscesses are uncommonly encountered at our institution. This cluster of 4 cases over a 1-year period has therefore led us to postulate that the severe drought may be aiding in the transmission of the bacteria. The cases also emphasize the propensity of nocardial infections to mimic other conditions, particularly malignancy, which may lead to delays in appropriate surgical treatment and antimicrobial therapy. The diagnosis requires a high clinical index of suspicion, with early tissue and microbiological diagnosis. Prolonged antimicrobial therapy is required to prevent relapse of the infection.     

Surgical site infections and supplemental perioperative oxygen in colorectal surgery patients: a systematic review

BACKGROUND: Four randomized trials have evaluated the impact of supplemental perioperative oxygen on the incidence of surgical site infections (SSIs), with mixed results. The objectives of this meta-analysis were: (1) To evaluate further the effect of supplemental perioperative oxygen on SSIs after colorectal surgery; and (2) to generate a strategy for future studies to determine definitively the value of this intervention. METHODS: We conducted a MEDLINE search to identify randomized trials of supplemental perioperative oxygen with a primary endpoint of SSI. Fixed-effects and random-effects models were employed, and the null association was tested for each. Tests also were performed for heterogeneity and publication bias. RESULTS: Four studies were identified that satisfied the search criteria. The total number of patients was 943, of whom 477 received supplemental oxygen and 466 served as controls. The pooled risk ratio (RR) for SSI favored the patients who received supplemental oxygen (RR = 0.68; 95% confidence interval [CI] 0.49, 0.94), but this difference was not maintained with a random-effects model (RR = 0.73; 95% CI 0.42, 1.28; p = 0.27). Heterogeneity was present among the studies. There was no evidence of publication bias. CONCLUSIONS: Supplemental perioperative oxygen is associated with a lower risk of SSI in patients undergoing colorectal surgery. The heterogeneity among the individual reports may be secondary to differences in study protocols.     

Clinical course of open metatarsal fractures

Little information exists regarding open fractures of the foot and no studies have reported open metatarsal fractures. Limited local soft tissue coverage makes this a distinct type of injury. Ten patients with open metatarsal fractures were treated. Six sustained Gustilo Grade I or II injuries; all healed without the need for additional soft tissue coverage. Four patients with Gustilo IIIB developed complications and all went on to eventually require amputation. This data indicates less severe open metatarsal fractures heal without complications, but more severe injuries require amputation.     

Electrocorticographically controlled brain-computer interfaces using motor and sensory imagery in patients with temporary subdural electrode implants. Report of four cases

Brain-computer interface (BCI) technology can offer individuals with severe motor disabilities greater independence and a higher quality of life. The BCI systems take recorded brain signals and translate them into real-time actions, for improved communication, movement, or perception. Four patient participants with a clinical need for intracranial electrocorticography (ECoG) participated in this study. The participants were trained over multiple sessions to use motor and/or auditory imagery to modulate their brain signals in order to control the movement of a computer cursor. Participants with electrodes over motor and/or sensory areas were able to achieve cursor control over 2 to 7 days of training. These findings indicate that sensory and other brain areas not previously considered ideal for ECoG-based control can provide additional channels of control that may be useful for a motor BCI.     

Laparoscopic versus open appendicectomy in children: A UK District General Hospital experience

Aims

The aim of this study was to evaluate the potential role of laparoscopic appendicectomy in reducing morbidity and length of stay in children compared to open procedures in a UK District General Hospital setting.

Methods

A three-year retrospective review of children ≤ 15 years with histologically confirmed appendicitis who underwent laparoscopic (LA) and/or open (OA) appendicectomy was performed. Choice of operation was based on individual surgeon’s preference and on patient’s body size. Data collected included rate of histologically complicated appendicitis, post-operative length of stay (LOS), and collective and differential morbidity rates, i.e., wound infection, intra-abdominal collection, and ileus. Chi-square and Mann–Whitney tests were used for statistical analysis. P < 0.05 was regarded as significant.

Results

Eighty children (70% male) were identified at median age 11 (3–15) years. They could be divided into complicated (n = 18, 22%) and simple appendicitis (n = 62, 78%). Appendicectomy was performed in all as an OPEN (n = 53, 66%) or LAPAROSCOPIC (n = 27, 34%) procedure. Both groups were comparable in gender distribution (P = 0.11) and rate of complicated appendicitis (30% vs. 19%, respectively; P = 0.27). Median age was significantly lower in the OPEN group [10 (3–15) vs. 12 (7–15) years; P < 0.004]. Laparoscopic appendicectomy had a significantly lower rate of collective morbidity (3.8% vs. 25.9%; P < 0.003), including lower rate of intra-abdominal collection (1.9% vs. 14.8%; P < 0.01). Median LOS was not significantly different (1 day vs. 2 days; P = 0.14).

Conclusion

Laparoscopic appendicectomy in children in a UK District General Hospital is safe and was associated with significantly less post-operative morbidity than the open technique.