Increased mean diffusivity of the caudal motor SNc identifies patients with REM sleep behaviour disorder and Parkinson's disease.

Idiopathic rapid eye movement sleep behaviour disorder (iRBD)-a Parkinson's disease (PD) prodrome-might exhibit neural changes similar to those in PD. Substantia nigra pars compacta (SNc) degeneration underlies motor symptoms of PD. In iRBD and early PD (ePD), we measured diffusion MRI (dMRI) in the caudal motor SNc, which overlaps the nigrosome-1-the earliest-degenerating dopaminergic neurons in PD-and in the striatum. Nineteen iRBD, 26 ePD (1.7 ± 0.03 years), and 46 age-matched healthy controls (HCs) were scanned at Western University, and 47 iRBD, 115 ePD (0.9 ± 0.01 years), and 56 HCs were scanned through the Parkinson's Progression Markers Initiative, using 3T MRI. We segmented the SNc and striatum into subregions using automated probabilistic tractography to the cortex. We measured mean diffusivity (MD) and fractional anisotropy (FA) along white-matter bundles and subregional surfaces. We performed group-level and classification analyses. Increased caudal motor SNc surface MD was the only iRBD-HCs and ePD-HCs difference replicating across datasets (padj < 0.05). No iRBD-ePD differences emerged. Caudal motor SNc surface MD classified patient groups from HCs at the single-subject level with good-to-excellent balanced accuracy in an independent sample (0.91 iRBD and 0.86 iRBD and ePD combined), compared to fair performance for total SNc surface MD (0.72 iRBD and ePD). Caudal motor SNc surface MD correlated significantly with MDS-UPDRS-III scores in ePD patients. Using dMRI and automated segmentation, we detected changes suggesting altered microstructural integrity in iRBD and ePD in the nigrostriatal subregion known to degenerate first in PD. Surface MD of the caudal motor SNc presents a potential measure for inclusion in neuroimaging biomarkers of iRBD and PD.

Subregional analysis of striatum iron in Parkinson's disease and rapid eye movement sleep behaviour disorder.

The loss of dopamine in the striatum underlies motor symptoms of Parkinson's disease (PD). Rapid eye movement sleep behaviour disorder (RBD) is considered prodromal PD and has shown similar neural changes in the striatum. Alterations in brain iron suggest neurodegeneration; however, the literature on striatal iron has been inconsistent in PD and scant in RBD. Toward clarifying pathophysiological changes in PD and RBD, and uncovering possible biomarkers, we imaged 26 early-stage PD patients, 16 RBD patients, and 39 age-matched healthy controls with 3 T MRI. We compared mean susceptibility using quantitative susceptibility mapping (QSM) in the standard striatum (caudate, putamen, and nucleus accumbens) and tractography-parcellated striatum. Diffusion MRI permitted parcellation of the striatum into seven subregions based on the cortical areas of maximal connectivity from the Tziortzi atlas. No significant differences in mean susceptibility were found in the standard striatum anatomy. For the parcellated striatum, the caudal motor subregion, the most affected region in PD, showed lower iron levels compared to healthy controls. Receiver operating characteristic curves using mean susceptibility in the caudal motor striatum showed a good diagnostic accuracy of 0.80 when classifying early-stage PD from healthy controls. This study highlights that tractography-based parcellation of the striatum could enhance sensitivity to changes in iron levels, which have not been consistent in the PD literature. The decreased caudal motor striatum iron was sufficiently sensitive to PD, but not RBD. QSM in the striatum could contribute to development of a multivariate or multimodal biomarker of early-stage PD, but further work in larger datasets is needed to confirm its utility in prodromal groups.

Infection After Open Long Bone Fractures: Can We Improve on Prophylaxis?

INTRODUCTION: Current standards recommend antibiotic prophylaxis administered after open fracture injury. The purpose of this study was to assess culture results in patients with open fracture-associated infections, hypothesizing that cultures obtained do not vary by Gustilo-Anderson (GA) classification. METHODS: We examined cultured bacterial species from patients with open long bone fractures that underwent irrigation and debridement at a Level 1 trauma center (2008-2016), evaluating our current and two hypothetical antibiotic protocols to assess whether they provided appropriate coverage. The antibiotic protocols included protocols 1 (cefazolin, with gentamicin added for type III fractures), 2 (vancomycin and cefepime) and 3 (ceftriaxone). RESULTS: GA classification was not associated with bacterial gram stain (P = 0.161), nor was it predictive of mono- versus polymicrobial infection (P = 0.094). Of 42 culture-positive infections, 31 were type III and 11 were type I or II fractures. 27% of the infections for type I or II fractures were caused by organisms targeted by protocol 1 (OR 0.18, 95% CI 0.04-0.82; P = 0.027). There was no difference in coverage by fracture type among protocol 2 (P = 0.771) or protocol 3 (P = 0.891). For type III fractures, protocol 2 provided 94% appropriate coverage compared to 68% and 61% coverage by protocols 1 and 3, respectively. CONCLUSION: For open fractures complicated by infection, isolated bacterial organisms do not correlate with GA open fracture classification, suggesting that hypothetical protocol 2 should be used for all fracture types. Protocol 2's broad coverage, across all GA fracture types, may prevent infection by organisms not covered by current antibiotic prophylaxis.

Case-Ascertainment Models to Identify Adults with Obstructive Sleep Apnea Using Health Administrative Data: Internal and External Validation.

BACKGROUND: There is limited evidence on whether obstructive sleep apnea (OSA) can be accurately identified using health administrative data. STUDY DESIGN AND METHODS: We derived and validated a case-ascertainment model to identify OSA using linked provincial health administrative and clinical data from all consecutive adults who underwent a diagnostic sleep study (index date) at two large academic centers (Ontario, Canada) from 2007 to 2017. The presence of moderate/severe OSA (an apnea-hypopnea index≥15) was defined using clinical data. Of 39 candidate health administrative variables considered, 32 were tested. We used classification and regression tree (CART) methods to identify the most parsimonious models via cost-complexity pruning. Identified variables were also used to create parsimonious logistic regression models. All individuals with an estimated probability of 0.5 or greater using the predictive models were classified as having OSA. RESULTS: The case-ascertainment models were derived and validated internally through bootstrapping on 5099 individuals from one center (33% moderate/severe OSA) and validated externally on 13,486 adults from the other (45% moderate/severe OSA). On the external cohort, parsimonious models demonstrated c-statistics of 0.75-0.81, sensitivities of 59-60%, specificities of 87-88%, positive predictive values of 79%, negative predictive values of 73%, positive likelihood ratios (+LRs) of 4.5-5.0 and -LRs of 0.5. Logistic models performed better than CART models (mean integrated calibration indices of 0.02-0.03 and 0.06-0.12, respectively). The best model included: sex, age, and hypertension at the index date, as well as an outpatient specialty physician visit for OSA, a repeated sleep study, and a positive airway pressure treatment claim within 1 year since the index date. INTERPRETATION: Among adults who underwent a sleep study, case-ascertainment models for identifying moderate/severe OSA using health administrative data had relatively low sensitivity but high specificity and good discriminative ability. These findings could help study trends and outcomes of OSA individuals using routinely collected health care data.

High acuity polytrauma centers in orthopaedic trauma: Decreasing patient mortality with effective resource utilization.

BACKGROUND: There is a select number of massive-volume, high-acuity trauma centers (HACs) in the United States. Expertise in polytrauma care has been associated with improved mortality in general surgery trauma, though has not been investigated in orthopaedic trauma. With complex polytrauma proficiency comes the inherent risk of intensive care, complications, and prolonged inpatient stays, without a commensurate increase in allocated resources. The purpose of this study was to compare mortality, complications, and length of stay in polytraumatized orthopaedic patients treated at HACs vs. low-acuity trauma centers (LACs). METHODS: The National Trauma Data Bank was queried for orthopaedic injuries with injury severity score (ISS)>15 and mortality, complications, hospital length of stay, ICU length of stay, ventilation duration, and demographics. Hospitals where at least 13% (median percentage of patients with ISS > 15 admitted to all hospitals) of total admissions had an ISS>15 were classified as HAC; all others were LACs. RESULTS: HACs admitted 86.8% of 28,314 patients with ISS>15. On univariate analysis, patients at HACs have 16% decreased odds of in-hospital mortality vs. LACs (p=0.005); the effect increased to 27% (p=0.002) on multivariate analysis. Patients at HACs have 63% greater odds of ICU admission (p<0.001), 48% higher odds of ventilatory support (p=<0.001), 38% increased odds of unplanned reoperation (p=0.007), and 37% increased odds of medical complications (p<0.001). On multivariate analysis, secondary outcome measures showed no significant difference between HACs and LACs. Patients at HACs had 2.8 days longer length-of-stay (p<0.001). CONCLUSION: Severely injured orthopaedic trauma patients have decreased mortality at HACs, despite having a higher average ISS and a higher prevalence of obesity and active smoking. While there is a higher incidence of ICU admission, mechanical ventilation, complications, and unplanned reoperation on univariate analysis, correction for ISS and patient factors enhances the effect of HACs on mortality, but removes the effect on secondary measures. Thus, HACs are life-saving institutions for polytraumatized orthopaedic patients, and the known resource demand of these hospitals is supported by their favorable outcome profile. LEVEL OF EVIDENCE: IV.

Is Operative Debridement Greater Than 24 Hours Post-admission Associated With Increased Likelihood of Post-operative Infection?

BACKGROUND: The historical "six-hour rule" as a golden hour for timing to debridement has been refuted in modern literature. Current standards prompt a timely debridement; however, in the setting of polytrauma, patients are often resuscitated for periods >24 h, with delayed orthopedic intervention. Therefore, we sought to determine the association between prolonged time to operative debridement (>24 h) and infection. METHODS: We conducted a retrospective review of patients with open fractures that underwent irrigation and debridement at a single institution from 2008 to 2016. Demographic, injury, and operative variables were collected. Infection was defined as the need for intravenous antibiotics and/or repeat irrigation and debridement. Chi-squared test and univariate logistic regression were performed. P < 0.05 was the cutoff for significance. RESULTS: Of 642 patients examined, 56 (8.7%) developed an infection. Prolonged time to debridement was not associated with increased infection rates (P = 1.00). Gustilo-Anderson classification was associated with increased risk of infection (type I: 2.1%, type II: 7.6%, and type III: 14.6%; P < 0.001). In univariate analysis, infection was associated with after-hours surgery (between 7 PM and 7 AM (odds ratio [OR] = 2.02; P < 0.02), definitive fixation more than 24 h post-admission (OR = 3.08; P < 0.001), wound closure more than 24 h post-admission (OR = 4.36; P < 0.001), and more than two operations performed post-admission (OR = 8.73; P < 0.001). Multivariate analysis of these factors found number of operations (OR = 7.13; P < 0.001) and time to definitive wound closure (OR = 4.04; P < 0.001) to be independent predictors of developing an infection. CONCLUSIONS: Our data suggests that there is no association between infection and prolonged time to debridement.

Impact of closed suction drainage after surgical fixation of acetabular fractures.

INTRODUCTION: The purpose of the present study was to evaluate the prevalence of closed suction drainage after a Kocher-Langenbeck (K-L) approach for surgical fixation of acetabular fractures and to determine the impact of closed suction drainage on patient outcomes. METHODS: This retrospective study reports on 171 consecutive patients that presented to a single level I trauma center for surgical fixation of an acetabular fracture. Medical records were reviewed to evaluate the use of closed suction drains. The primary outcomes measures were rate of packed red blood cell (PRBC) transfusion and length of hospital stay (LOS). Secondary outcome measures were 30-day post-operative wound complication and 1-year deep infection rates. RESULTS: Of the 171 patients included in this study, 140 (82%) patients were treated with drains. There was a significant association between the use of closed suction drainage and post-operative blood transfusion rate (p = 0.002). Thirty-five patients (25%) treated with drains required a post-operative blood transfusion compared to 0% in the no drain cohort. Regarding the total number of drains used, for every additional closed suction drain that was placed beyond a single drain, the odds of receiving a blood transfusion doubled (p = 0.002). Use of closed suction drainage was associated with a significantly longer LOS (p = 0.015), and no difference in wound complication or deep infection rates. CONCLUSION: The use of closed suction drains for treatment of acetabular fractures using a K-L approach is associated with increased rates of blood transfusion and increased length of hospital stay, with no impact on surgical site infection rates. The results of this study suggest against routine drain usage in acetabular surgery.

Determinants of Length of Stay After Operative Treatment for Femur Fractures.

OBJECTIVES: To investigate the determinants of length of stay (LOS) for patients surgically treated for femur fractures. DESIGN: Retrospective medical record review. SETTING: Urban Level I Trauma Center. PARTICIPANTS: Three hundred twenty-one patients operatively treated for femur fractures between July 12, 2015 and July 12, 2016. INTERVENTION: Intramedullary nailing, open reduction internal fixation, arthroplasty, or other (percutaneous screw or multiple hardware/technique) definitive fixation of femur fracture. MAIN OUTCOME MEASUREMENTS: Hospital LOS. RESULTS: Median LOS was 6.43 days (range 1-76 days). Patients were divided into 2 groups: LOS ≥6 days (n = 171) and LOS <6 days (n = 150). Univariate analysis revealed several preoperative, perioperative, and postoperative factors associated with extended LOS. Multivariate analysis demonstrated frailty [odds ratio (OR), 20.58], medical complications (OR, 20.09), an upper extremity injury (OR, 9.97), an ipsilateral lower extremity injury (OR, 6.34), time to definitive fixation (OR, 2.12), time to first physical therapy visit (OR, 1.77), and Injury Severity Score (OR, 1.14) were independent predictors of LOS. CONCLUSIONS: By understanding the determinants of LOS for patients with femur fracture, high-risk patients can be identified and interventions can be enacted. Earlier fixation and aggressive management of medical complications may decrease patients' LOS. Patients who meet frailty criteria under the Modified Frailty Index are at a twenty-fold increased risk of staying longer than 6 days after having a femur fracture. By identifying these patients on admission, strategies can be devised to reduce their LOS and economic burden. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The frail fail: Increased mortality and post-operative complications in orthopaedic trauma patients.

OBJECTIVE: The burgeoning elderly population calls for a robust tool to identify patients with increased risk of mortality and morbidity. This paper investigates the utility of the MFI as a predictor of morbidity and mortality in orthopaedic trauma patients. DESIGN: Retrospective review of the NSQIP database to identify patients age 60 and above who underwent surgery for pelvis and lower extremity fractures between 2005 and 2014. MAIN OUTCOMES AND MEASURES: For each patient, an MFI score was calculated using NSQIP variables. The relationship between the MFI score and 30-day mortality and morbidity was determined using chi-square analysis. MFI was compared to age, American Society of Anesthesiologists physical status classification, and wound classifications in multiple logistic regression. RESULTS: Study sample consisted of 36,424 patients with 27.8% male with an average age of 79.5 years (SD 9.3). MFI ranged from 0 to 0.82 with mean MFI of 0.12 (SD 0.09). Mortality increased from 2.7% to 13.2% and readmission increased from 5.5% to 18.8% with increasing MFI score. The rate of any complication increased from 30.1% to 38.6%. Length of hospital stay increased from 5.3days (±5.5days) to 9.1days (±7.2days) between MFI score 0 and 0.45+. There was a stronger association between 30-day mortality and MFI (aOR for MFI 0.45+: 2.6, 95% CI: 1.7-3.9) compared to age (aOR for age: 1.1, 95% CI: 1.1-1.1) and ASA (aOR 2.5, 95% CI: 2.3-2.7). CONCLUSIONS AND RELEVANCE: MFI was a significant predictor of morbidity and mortality in orthopaedic trauma patients. The use of MFI can provide an individualized risk assessment tool that can be used by an interdisciplinary team for perioperative counseling and to improve outcomes.

Humeral Shaft Fracture Fixation: Incidence Rates and Complications as Reported by American Board of Orthopaedic Surgery Part II Candidates.

BACKGROUND: Despite extensive research regarding patient outcomes after operative fixation of humeral shaft fractures by means of open reduction and internal fixation (ORIF) or intramedullary nailing (IMN), no current consensus exists regarding the optimal surgical treatment. The objective of this study was to compare IMN and plate fixation (ORIF) of humeral shaft fractures by using the American Board of Orthopaedic Surgery (ABOS) Part II operative database to analyze incidence rates, changes in management trends over time, early complications, and factors affecting the management choice. METHODS: The ABOS database is a collection of surgical cases that are self-reported by orthopaedic candidates approved for admission to the ABOS oral examination. The database was searched for records from 2004 to 2013 for humeral shaft surgical cases as indicated by Current Procedural Terminology (CPT) codes 24515 (open reduction internal fixation) and 24516 (insertion of intramedullary nail) pertaining to humeral shaft fractures. The geographic region and fellowship training of the candidates; the year of surgery, diagnosis code, age, and sex of the patients; and the surgeon-reported complications were analyzed. RESULTS: The search identified 3,430 surgically treated humeral shaft fractures that were reported to the ABOS database from 2004 to 2013. A significant decline in IMN use was seen from 2004 (42.9%) to 2013 (21.2%, p < 0.001). The IMN cohort had lower complication rates pertaining to both infections (1.5% compared with 3.0% for ORIF, p = 0.007) and nerve palsies (3.1% compared with 7.8%, p < 0.001). No significant difference was seen in the rate of nonunion (1.3% for IMN compared with 1.6% for ORIF, p = 0.63), although follow-up may be too short to demonstrate a difference. The IMN cohort did have significantly higher mortality (4.9% compared with 0.7% for ORIF, p < 0.001). Subset analysis demonstrated that the IMN cohort had significantly more pathologic fractures (26.8% compared with 1.5% of the fractures treated with ORIF, p < 0.001). CONCLUSIONS: Although the overall incidence of fixation of humeral shaft fractures was unchanged from 2004 to 2013, there was a significant shift from IMN to ORIF using plate fixation during this time period. Possible reasons for this shift in treatment to ORIF include the potential impact of recent publications highlighting complications of IMN and increased surgeon attention to cost containment. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Use of Near-Infrared Spectroscopy to Detect Sustained Hyperaemia Following Lower Extremity Trauma.

INTRODUCTION: Patients who sustain lower extremity trauma are at highest risk for acute compartment syndrome (ACS) during the first 48 hours after surgical stabilization. Near-infrared spectroscopy (NIRS) may be a useful monitoring tool for ACS during this period; however, expected normal values have yet to be established. This study sought to evaluate whether the expected hyperaemic response is present 48 hours postoperatively, using NIRS. MATERIALS AND METHODS: Participants consisted of 25 cases with acute unilateral lower extremity fractures. NIRS measurements for hemoglobin saturated with oxygen (rSO2) were taken approximately 48 hours after surgical stabilization for each compartment bilaterally, using the contralateral (uninjured) leg as an internal control. RESULTS: Mean rSO2 values taken 48 hours from surgical stabilization from each compartment of the patients' injured legs were significantly higher than the mean values of the contralateral legs (injured = 70, 68, 72, 70; contralateral = 55, 54, 57, 56 for anterior, lateral, deep posterior, and superficial posterior compartments, respectively; p < 0.0001 for all compartments). CONCLUSIONS: These results suggest that the hyperaemic response to injury remains present at 48 hours after surgical stabilization, and that NIRS values in an injured extremity should be expected to remain elevated throughout the window of concern for ACS. NIRS may be a valuable tool in monitoring leg injuries during this critical time period.

Improving Spanning-Knee External Fixator Stiffness: A Biomechanical Study.

The purpose of this study was to test and compare external fixator construct stiffness using pin-to-bar clamps or multipin clamps across 2 external fixation systems. Constructs were tested with 8-mm and 11-mm-diameter bar systems and pin-to-bar or multipin clamps. Three construct designs were tested: construct 1 with a single crossbar and pin-to-bar clamps, construct 2 with 2 crossbars and pin-to-bar clamps, and construct 3 with 2 crossbars and multipin clamps. The stiffness of each construct (N = 24) was tested using anterior-posterior bending. Two crossbars and pin-to-bar clamps resulted in the highest mean stiffness. Constructs with a single crossbar and pin-to-bar clamps had a similar average stiffness compared with constructs with 2 crossbars and multipin clamps. Pin-to-bar clamps with 2 crossbars result in stronger spanning-knee external fixators than constructs using multipin clamps.

Value of a Dedicated Saturday Orthopaedic Trauma Operating Room.

OBJECTIVES: To determine the effect of an additional scheduled operative day on length of stay, distribution of caseload, waiting time to surgery, and direct variable hospital costs. DESIGN: Retrospective chart review. SETTING: Urban level 1 trauma center. PATIENTS: Consecutive operative tibia and femur fractures admitted from November 1, 2009, to October 31, 2011. INTERVENTION: Addition of a dedicated Saturday orthopaedic trauma operating room. MAIN OUTCOME MEASUREMENTS: Length of stay, distribution of caseload, and waiting time to surgery. RESULTS: The overall length of stay for all trauma patients admitted with femur or tibia fractures was significantly reduced by 2.7 days from a mean of 14.0-11.3 days (P value 0.018). Additionally, there was a trend toward shorter waiting time to surgery (average reduction of 25.1 hours) for patients admitted on a Friday (48.6 vs. 23.5 hours, P value 0.06). Furthermore, there was an increase in the number of cases performed on Saturdays by 59% (6.2% of the total caseload), whereas the originally disproportionally high number of cases on Mondays was appropriately reduced by 33% (6.7% of the total caseload). The estimated direct variable cost savings per year for the hospital was $1.13 million. CONCLUSIONS: Overall, these findings support the continuation of a dedicated Saturday orthopaedic trauma operating room and can provide the foundation for other departments with similar circumstances to negotiate for more dedicated operative time on weekends to improve efficiency. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effect of a Dedicated Orthopaedic Advanced Practice Provider in a Level I Trauma Center: Analysis of Length of Stay and Cost.

OBJECTIVES: The objective of this study is to analyze the effect of an orthopaedic trauma advanced practice provider on length of stay (LOS) and cost in a level I trauma center. The hypothesis of this study is that the addition of a single full-time nurse practitioner (NP) to the orthopaedic trauma team at a level I Trauma center would decrease overall LOS and hospital cost. METHODS: A retrospective chart review of all patients discharged from the orthopaedic surgery service 1 year before the addition of a NP (pre-NP) and 1 year after the hiring of a NP (post-NP) were reviewed. Chart review included age, gender, LOS, discharge destination, intravenous antibiotic use, wound VAC therapy, admission location, and length of time to surgery. Statistical analysis was performed using the Wilcoxon/Kruskal-Wallis test. RESULTS: The hiring of a NP yielded a statistically significant decrease in the LOS across the following patient subgroups: patients transferred from the trauma service (13.56 compared with 7.02 days, P < 0.001), patients aged 60 years and older (7.34 compared with 5.04 days, P = 0.037), patients discharged to a rehabilitation facility (10.84 compared with 8.31 days, P = 0.002), and patients discharged on antibiotics/wound VAC therapy (15.16 compared with 11.24 days, P = 0.017). Length of time to surgery was also decreased (1.48 compared with 1.31 days, P = 0.37). CONCLUSIONS: The addition of a dedicated orthopaedic trauma advanced practice provider at a county level I trauma center resulted in a statistically significant decrease in LOS and thus reduced indirect costs to the hospital. LEVEL OF EVIDENCE: Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Subcutaneous depth in a traumatized lower extremity.

BACKGROUND: Acute compartment syndrome is a rare but serious consequence of traumatic leg injury. Near-infrared spectroscopy (NIRS) is able to measure oxygenation to a depth of 2 cm to 3 cm below the skin, raising concerns over the ability of NIRS to accurately determine oxygenation of injured leg compartments in the presence of swelling and in the obese. The purpose of this study was to measure the thickness of the subcutaneous tissue overlying the posterior muscle compartment in subjects with tibia fractures to determine if it might compromise rSO2 measurement in the muscle. METHODS: Data were analyzed on 50 patients with severe leg injuries. Distance from the skin to the fascia in the superficial posterior compartment of both legs was measured on each patient using a portable ultrasound device. RESULTS: Subject age ranged from 18 years to 65 years (mean, 39 years), with 43 male and 7 female patients. The mean (SD) subcutaneous adipose tissue thickness (ATT) was 6.98 (3.17) mm for the injured leg and 7.06 (3.37) mm for the uninjured leg, and the mean body mass index for the group was 27.08 kg/m. No significant correlation was found between the ATT of the injured or uninjured legs and body mass index. Mean comparison testing revealed no difference in ATT between the injured and uninjured legs (null hypothesis: equal means, p > 0.05). Of the 50 subjects analyzed, no subject had a subcutaneous depth of more than 2 cm on the injured or uninjured leg. CONCLUSION: These data suggest that, within this traumatically injured population, symptoms associated with leg injury (such as swelling and edema) do not significantly affect the distance from the skin to the fascia. It is also notable that subcutaneous depth beyond the 2-cm mark (validated in previous studies) is a rare occurrence in this population. These results further support the use of continuous NIRS monitoring for diagnosis of acute compartment syndrome. LEVEL OF EVIDENCE: Therapeutic study, level IV.

Relationship between near infrared spectroscopy and intra-compartmental pressures.

BACKGROUND: Near infrared spectroscopy (NIRS) has been suggested as a possible means for detecting perfusion deficits in patients with acute compartment syndrome (ACS). STUDY OBJECTIVES: To longitudinally examine NIRS in an ACS model to determine its responsiveness to decreasing perfusion pressure. METHODS: A NIRS sensor pad was placed under a tourniquet over the anterior compartment in the mid-tibia region on 20 volunteers. Initial perfusion pressures and NIRS values were recorded. The tourniquet pressure was sequentially raised by 10 mm Hg in 10-min intervals until systolic pressure was surpassed. NIRS values and perfusion pressure were determined at the end of each 10-min interval. RESULTS: There was no change in mean NIRS values from the initial baseline until 30 mm Hg of perfusion pressure was reached. Additionally, a statistically significant drop in mean NIRS values was observed as perfusion pressures dropped from 10 mm Hg to 0 mm Hg, and again with subsequent decreases of 10 mm Hg perfusion pressure until systolic pressure was surpassed. CONCLUSIONS: These results coincide with previously published studies using alternative methods of measuring blood flow or perfusion. NIRS values were responsive to decreasing perfusion pressures over a longitudinal period of time in an ACS model. These results suggest that NIRS may be useful for continuous, non-invasive monitoring of patients for whom ACS is a concern. Additional studies on traumatized patients are required.

Multi-disciplinary update on pelvic fracture associated bladder and urethral injuries.

Pelvic ring fractures often result in severely injured patients with multiple organ injuries. The most common associated injuries are intraabdominal or urogenital, and urogenital injuries are the most common associated injuries in those with severe pelvic fractures. Prompt and effective diagnosis and management of these injuries is essential to successful outcomes, but this is potentially complicated by poor communication and coordination among the many specialists involved. To address this, we present a multi-disciplinary review of pelvic fracture-associated bladder and urethral injuries that is specifically geared towards orthopaedic, urology, and trauma surgeons caring for these patients.