A 3-Dimensional Evaluation of the Effects of Unilateral Vertical Mandibular Distraction Osteogenesis on Airway Volume Among Patients With Hemifacial Microsomia.

OBJECTIVE: The aim of this study was to evaluate the volumetric airway changes using three-dimensional images following unilateral vertical mandibular distraction osteogenesis (uVMD) among patients with hemifacial microsomia (HFM). DESIGN: This retrospective study analyzed cone-beam computed tomography (CBCT) scans of patients with HFM at three different timepoints; pretreatment (T0), posttreatment (T1), and at least 6 months post-distraction (T2). The individuals underwent uVMD between December 2018-Januaray 2021. The nasopharyngeal (NP) volume, oropharyngeal (OP) volume, and the area of maximum constriction (MC) were measured. Wilcoxon signed-rank test was used to compare the airway volumes between T0-T1, T1-T2, and T0-T2. RESULTS: Five patients met the inclusion criteria (mean age = 10.4 years; 1 female, 4 males). Intraclass correlation analysis showed excellent interrater reliability (r > .86, P < .001). Posttreatment, the OP airway volume exhibited a significant mean increase of 56% (P = .043) from T0 to T1, but decreased from T1-T2 by 13%. Likewise, the total airway volume presented with a significant mean increase of 48% between T0-T1 (P = .044), and a decrease of 7% from T1-T2. The changes in the NP airway volume and area of MC were not statistically significant (P > .05), but an increase in the mean values were observed. CONCLUSION: Surgical intervention with uVMD may significantly increase the OP airway volume and the total airway volume among patients with HFM immediately after distraction. However, the statistical significance diminished after six months post-consolidation, but the mean percent change may remain of clinical significance. The NP volume did not seem to show significant changes in response to uVMD.

Lumbar surgical drains do not increase the risk of infections in patients undergoing spine surgery.

PURPOSE: The aim of this study was to characterize if the use of surgical drains or length of drain placement following spine surgery increases the risk of post-operative infection. METHODS: Records of patients undergoing elective spinal surgery at a tertiary care center were collected between May 5, 2016 and August 16, 2018. Pre-operative baseline characteristics were recorded including patient's demographics and comorbidities. Intraoperative procedure information was documented related to procedure type, blood loss, and antibiotics used. Following surgery, patients were then further subdivided into two groups: patients who were discharged with a spinal surgical site drain and patients who did not receive a drain. Post-operative surgical variables included length of stay (LOS), drain length, number of antibiotics given, and type of post-operative infection. Univariate and multivariate statistical analysis was conducted. RESULTS: A total of 671 patients were included in the current study, 386 (57.5%) with and 285 (42.5%) without the drain. The overall infection rate was 5.7% with 6.22% among patients with the drain compared to 4.91% in patients without drain. The univariate analysis identified the following variables to be significantly associated with the infection: total number of surgical levels, spinal region, blood loss, redosing of antibiotics, length of stay, length of drain placement, and number of antibiotics (P < 0.05). However, the multivariate analysis none of the predictors was significant. CONCLUSIONS: The current study shows that the placement of drain does not increase rate of infection, irrespective of levels, length of surgery, or approach.

Biased Competition during Long-term Memory Formation.

A key task for the brain is to determine which pieces of information are worth storing in memory. To build a more complete representation of the environment, memory systems may prioritize new information that has not already been stored. Here, we propose a mechanism that supports this preferential encoding of new information, whereby prior experience attenuates neural activity for old information that is competing for processing. We evaluated this hypothesis with fMRI by presenting a series of novel stimuli concurrently with repeated stimuli at different spatial locations in Experiment 1 and from different visual categories (i.e., faces and scenes) in Experiment 2. Subsequent memory for the novel stimuli could be predicted from the reduction in activity in ventral temporal cortex for the accompanying repeated stimuli. This relationship was eliminated in control conditions where the competition during encoding came from another novel stimulus. These findings reveal how prior experience adaptively guides learning toward new aspects of the environment.