Predictions of total work based on measures of muscle strength and hop performance in individuals after ACL reconstruction.

OBJECTIVES: The purpose of this study was to determine the ability to utilize clinical measures of hop performance and thigh muscle strength to predict total limb work, a measure of cumulative single leg power, in young athletes at the time of return to sport after ACLR. We hypothesized that hop test performance and thigh muscle strength would predict total limb work during a maximal effort repeated vertical single-leg jump and that hop test performance would better predict total limb work during a maximal effort repeated vertical single-leg jump than measures of thigh strength. DESIGN: Cross-sectional study. PARTICIPANTS: Analysis on data from 50 individuals after unilateral ACLR (74% women, age 14-23 years) MAIN OUTCOME MEASURES: Performed 10-s repeated vertical single-leg jump test on a force platform where single limb power and resultant total work were calculated. At the same session, participants completed a clinical single leg hop test battery and thigh strength testing. RESULTS: All clinical measures were associated with total work during the repeated vertical single-leg jump test on the involved and uninvolved limbs, respectfully. After controlling for height and weight, quadriceps femoris peak torque at 180°/s was the strongest predictor of total work for both limbs. On the involved limb, performance on the triple hop test for distance also uniquely contributed to the prediction of total work. CONCLUSIONS: Quadriceps femoris muscle strength and distance hop test performance predict total limb work capacity of the involved limb during a single-leg dynamic task. Optimizing both measures after ACLR may positively impact vital components of sports performance.

A Review of Workload-Monitoring Considerations for Baseball Pitchers.

Because of the unique demands of a pitch, baseball players have the greatest percentage of injuries resulting in surgery among high school athletes, with a majority of these injuries affecting the shoulder and elbow due to overuse from throwing. These injuries are believed to occur because of repeated microtrauma to soft tissues caused by the repetitive mechanical strain of throwing. Researchers and practitioners have suggested that baseball pitchers' workloads are a significant risk factor for injury in adolescent players, resulting in lost time and slowing of performance development. The purpose of our review was to investigate the current research relative to monitoring workload in baseball throwers and discuss techniques for managing and regulating cumulative stress on the arm, with a focus on preventing injury and optimizing performance in adolescent baseball pitchers.

In-home neurogaming: Demonstrating the impact of valid gesture recognition method on high volume kinematic outcomes.

The process of cleaning motion capture data of aberrant points has been described as "the bane of motion capture operators". Yet, managing the high volume kinematic data generated through in-home neurogames requires data quality control that, executed insufficiently, jeopardizes accuracy of outcomes. To begin to address this issue at the intersection of biomechanics and "big data", we performed a secondary analysis of a neurogame, evaluating gesture count as well as shoulder and elbow joint angle outcomes calculated from kinematic data in which valid gestures were identified through 3 methods: visual review of regions of interest by an expert (BP); manufacturer-recommended data smoothing (MS); and automated methods (AI). We hypothesized that upper extremity kinematic outcomes from BP would be matched by AI but not MS methods. From one person with post-stroke hemiparesis, upper-extremity kinematic data were collected for 6 days over 2 weeks using a Microsoft Kinect™-based neurogame. We calculated gesture count, shoulder angle, and elbow angle outcomes from data managed using BP, MS, and AI methods. BP identified 1929 valid gestures total over 6 days which was different than the other two methods (p = 0.0015). In contrast, the AI algorithm with best precision identified 4372 and MS identified 4459 valid gestures. Furthermore, angle outcomes calculated from AI and MS methods resulted in different values than BP (p < 0.001 for 5 of 6 variables). More research is needed to automate treatment of high volume, low quality motion data to support investigation of motion associated with in-home rehabilitation neurogames.

The relationship between frontal plane trunk control during landing and lower extremity muscle strength in young athletes after anterior cruciate ligament reconstruction.

BACKGROUND: Lower extremity landing asymmetries are common and associated with strength deficits after anterior cruciate ligament reconstruction. However, less is known regarding trunk control during landing. This study's hypotheses were that frontal plane trunk excursion during single-leg landing would be greater in young athletes after anterior cruciate ligament reconstruction compared to controls and would be associated with strength deficits. METHODS: Participants included 130 young athletes recently cleared for return-to-sport following anterior cruciate ligament reconstruction and 56 uninjured young athletes. Frontal plane trunk excursion was quantified using three-dimensional motion analysis during a single-leg landing task. Quadriceps and hip abduction strength were measured using an isokinetic dynamometer. Frontal plane trunk excursion was compared between the anterior cruciate ligament reconstruction and control groups and among quadriceps strength subgroups using independent t-tests and one-way analysis of variance. Linear regression examined the association between frontal plane trunk excursion and strength measures in the anterior cruciate ligament reconstruction group. FINDINGS: The anterior cruciate ligament reconstruction group demonstrated greater frontal plane trunk excursion compared to controls. The low-quadriceps group demonstrated greater frontal plane trunk excursion compared to both the high-quadriceps and control groups. Additionally, the high-quadriceps group demonstrated greater frontal plane trunk excursion compared to controls. In the anterior cruciate ligament reconstruction group, lower quadriceps and hip abduction strength were weakly associated with greater frontal plane trunk excursion. INTERPRETATION: Young athletes at time of return-to-sport after anterior cruciate ligament reconstruction demonstrated increased frontal plane trunk excursion during single-leg landing. Additionally, increased frontal plane trunk excursion was weakly associated with strength deficits.

Ostomy Usage for Colorectal Trauma in Combat Casualties.

INTRODUCTION: The role for diverting ostomy as a method to help reduce morbidity and mortality has been well established in the combat trauma population. However, factors that influence the type of ostomy used and which ostomies become permanent are poorly studied. We examine patterns of ostomy usage and reversal in a large series of combat trauma patients. METHODS: We performed a retrospective review of combat casualties treated at our continental U.S. military treatment facility from 2003 to 2015. All patients who underwent ostomy formation were included. Clinical and demographic factors were collected for all patients including the type of ostomy and whether or not ostomy reversal took place. Patients were grouped and analyzed based on ostomy type and by ostomy reversal. RESULTS: We identified 202 patients who had ostomies created. End colostomies were most common (N = 149) followed by loop colostomies (N = 34) and end ileostomies (N = 19). Casualties that underwent damage control laparotomy (DCL) were less likely to have a loop colostomy created (p < 0.001). Ostomy reversal occurred in 89.9% of patients. There was no difference in ostomy reversal rates by ostomy type (p = 0.080). Presence of a pelvic fracture was associated with permanent ostomy (OR = 3.28, p = 0.019), but no factor independently predicted a permanent ostomy on multivariate analysis. DISCUSSION: DCL and a severe perineal injury most strongly influence ostomy type selection. Most patients undergo colostomy reversal, and no factor independently predicted an ostomy being permanent. These findings provide a framework for understanding the issue of fecal diversion in the combat trauma population and inform military surgeons about injury patterns and treatment options.

Changes in Throwing Arm Mechanics at Increased Throwing Distances During Structured Long-Toss.

BACKGROUND: Elbow injuries among adolescent baseball players have been outpacing those of college and professional players. In attempts to prevent injuries and maximize return-to-play potential following injury, attention has been focused on "return to throw" programs, which include long-toss throws. Because the few studies that were conducted on long-toss throwing focused primarily on college-aged athletes, it is not known what type of load is incurred at the elbow during interval throwing progression among high school baseball players. PURPOSE: To quantify the change in arm slot, arm speed, shoulder external rotation, and elbow varus torque across increasing throwing distances within a given athlete. STUDY DESIGN: Descriptive laboratory study. METHODS: Ninety-five high school baseball players performed a long-toss protocol while wearing an inertial sensor and sleeve. Each participant was tested for 5 throws at distances of 9 m, 18 m, 27 m, 37 m, and 46 m. Linear mixed-effects models and likelihood ratio tests were used to estimate the within-participant relationship between throw distance and arm slot, arm speed, shoulder external rotation, and elbow varus torque. RESULTS: Arm slot ( P < .01), arm speed ( P < .01), shoulder external rotation ( P < .01), and elbow varus torque ( P < .01) were significantly associated with long-toss throw distance. As the throw distance increased, there was an increase in arm speed and shoulder external rotation and a decrease in arm slot for each distance. However, elbow varus torque increased with each distance up to 37 m and then remained the same at 46 m. CONCLUSION: The use of longer distances for conditioning and rehabilitation may be beneficial in increasing shoulder range of motion and arm speed; however, precaution needs to be taken, as throwing longer distances are accompanied by an increase in arm rotation, arm speed, and elbow torque, with a decrease in arm slot. CLINICAL RELEVANCE: Return-to-throw programs have been utilized by sports medicine clinicians and coaches to help guide a player during rehabilitation. These programs involve throwing at increased efforts through increased distances with no immediate feedback on elbow stress. This investigation describes arm biomechanical changes during submaximum interval throwing and demonstrates a tool that can be utilized to measure arm stress in real time for clinicians and athletes progressing through an interval throwing program.

Assessing Risk and Related Complications after Reversal of Combat-Associated Ostomies.

BACKGROUND: During the past decade of conflict, numerous patients with combat-associated injuries required the formation of an ostomy. However, outcomes in those patients undergoing ostomy reversal have yet to be analyzed. We review the experience and identify risk factors for complications after ostomy reversal in a series of patients with combat injuries at our military treatment facility. STUDY DESIGN: A retrospective review of patients with combat-associated injuries managed with a diverting ostomy who underwent ostomy reversal at our military treatment facility during a 13-year period. Demographic and clinical data were collected for all patients and postoperative complications were identified. Multivariate analysis was performed to identify independent risk factors for complications after reversal. Complication rates were calculated for 90-day periods of time after ostomy creation and best-fit curve analysis was conducted. RESULTS: Ninety-nine patients were identified who underwent ostomy reversal. Forty patients (40.4%) suffered a post-reversal complication. On multivariate analysis, older age (odds ratio 1.11/y; p = 0.038), severe perineal injury indication for diversion (odds ratio 4.37; p = 0.028), and increased time interval between ostomy creation and reversal (odds ratio 1.005/d; p = 0.037), were independently associated with postoperative complications. A cubic regression best fit quarterly complication rate data (R2 0.526; p < 0.001) and calculates a minimum complication rate for reversal 90 to 180 days after ostomy creation. CONCLUSIONS: Ostomy reversal in patients wounded in combat is a major undertaking with a high complication rate. The finding of a shorter interval from ostomy creation to reversal independently associated with a reduction in complications provides a modifiable risk factor to guide future practice and potentially reduce complications. Our modeling suggests reversal in the 3- to 6-month time frame can have the lowest rate of complications. Future research to reduce complications is indicated, especially in older patients with perineal wounds.

Laparoscopy for Colon Cancer.

The use of laparoscopy has become widespread across many surgical specialties. Its utility as treatment for colon cancer was initially met with hesitancy due to concern for port site and wound recurrences; however, this was later disproven by large retrospective series. Subsequently, there have been multiple, large, prospective, randomized studies evaluating laparoscopic versus open colectomy for colon cancer. All studies yielded similar results and showed no statistical difference in overall survival, disease-free survival, and recurrence. Additionally, these studies revealed similar operative outcomes with respect to complication rates, perioperative mortality, and conversion to open colectomy, as well as equivalent oncologic resections. Overall in the laparoscopic colectomy groups, hospital stays were shorter, and often times patients required less narcotics postoperatively, but laparoscopic operative times were longer. With adequate training, the use of laparoscopy can be safely employed for patients with colon cancer.

Relationships Between Standing Frontal-Plane Knee Alignment and Dynamic Knee Joint Loading During Walking and Jogging in Youth Who Are Obese.

BACKGROUND: Youth who are obese have high risk of poor knee health and cartilage damage. Understanding factors which may affect knee health in youth who are obese is critical for preservation of knee integrity and function. OBJECTIVE: This study compared standing frontal-plane knee alignment and knee loading patterns between youth who are obese and those of healthy weight and determine the association between knee alignment and knee loading patterns during walking and jogging. DESIGN: This study used a cross-sectional matched pair design. METHODS: Twenty youth who were obese and 20 youth who were healthy-weight (ages 11-18 years) were recruited. Three-dimensional motion analysis quantified standing frontal-plane knee alignment as well as frontal- and sagittal-plane knee moments during walking and jogging. Paired t -tests, multiple analysis of covariance, and Spearman's rank correlation coefficients were used for analysis. RESULTS: The youth who were obese demonstrated greater knee valgus in standing ( P  = 0.02), lower normalized peak external knee adduction moments during walking ( P  = 0.003), and greater normalized peak external knee extension moments during jogging ( P  = 0.003) compared with the youth who were healthy-weight. Standing knee alignment did not correlate with knee moments in the youth who were obese. LIMITATIONS: Results are limited to small, homogeneous cohorts. The standing alignment methodology is not validated in this population and may limit interpretation of results. CONCLUSION: Youth who are obese stand in more knee valgus and have altered knee loading patterns during walking and jogging compared with youth who are healthy-weight. Frontal-plane knee alignment does not correlate with frontal-plane knee loading patterns in youth who are obese. A better understanding of other mechanisms related to joint loading in youth who are obese is necessary to maintain long-term joint integrity in this population.

Hamstring Strength Asymmetry at 3 Years After Anterior Cruciate Ligament Reconstruction Alters Knee Mechanics During Gait and Jogging.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) using a hamstring tendon autograft often results in hamstring muscle strength asymmetry. However, the effect of hamstring muscle strength asymmetry on knee mechanics has not been reported. HYPOTHESIS: Participants with hamstring strength asymmetry would demonstrate altered involved limb knee mechanics during walking and jogging compared with those with more symmetric hamstring strength at least 2 years after ACLR with a hamstring tendon autograft. STUDY DESIGN: Controlled laboratory study. METHODS: There were a total of 45 participants at least 2 years after ACLR (22 male, 23 female; mean time after ACLR, 34.6 months). A limb symmetry index (LSI) was calculated for isometric hamstring strength to subdivide the sample into symmetric hamstring (SH) (LSI ≥90%; n = 18) and asymmetric hamstring (AH) (LSI <85%; n = 18) groups. Involved knee kinematic and kinetic data were collected using 3-dimensional motion analysis during gait and jogging. Peak sagittal-, frontal-, and transverse-plane knee angles and sagittal-plane knee moments and knee powers were calculated. Independent-samples t tests and analyses of covariance were used to compare involved knee kinematic and kinetic variables between the groups. RESULTS: There were no differences in sagittal- and frontal-plane knee angles between the groups ( P > .05 for all). The AH group demonstrated decreased tibial internal rotation during weight acceptance during gait ( P = .01) and increased tibial external rotation during jogging at initial contact ( P = .03) and during weight acceptance ( P = .02) compared with the SH group. In addition, the AH group demonstrated decreased peak negative knee power during midstance ( P = .01) during gait compared with the SH group, after controlling for gait speed, which differed between groups. CONCLUSION: Participants with hamstring strength asymmetry showed altered involved knee mechanics in the sagittal plane during gait and in the transverse plane during gait and jogging compared with those with more symmetric hamstring strength. CLINICAL RELEVANCE: Hamstring strength asymmetry is common at 3 years after ACLR with a hamstring tendon autograft and affects involved knee mechanics during gait and jogging. Additional research is warranted to further investigate the longitudinal effect of these alterations on knee function and joint health after ACLR.

Portable Myoelectric Brace Use Increases Upper Extremity Recovery and Participation But Does Not Impact Kinematics in Chronic, Poststroke Hemiparesis.

The authors examined the efficacy of an 8-week regimen combining repetitive task-specific practice (RTP) with a myoelectric brace (RTP+Myomo) on paretic upper extremity (UE; use in valued activities, perceived recovery, and reaching kinematics) in 12 subjects (4 men; M age = 53.5 years; mean time poststroke = 61.7 months). Seven subjects were administered RTP+Myomo therapy, and 5 were administered RTP only. Both groups participated in individualized, 45-min therapy sessions occurring 3 days/week over an 8-week period. The arm, hand ability, activities of daily living, and perceptions of recovery subscales of the Stroke Impact Scale (SIS), as well as UE reaching kinematics, assessed before and after the intervention. Subjects in the RTP+Myomo group showed greater improvements on all SIS subscales, with the recovery scale reaching statistical significance (p = .03). Subjects in the RTP-only group showed a greater increase in hand velocity in the reach up task (p = .02), but no changes were observed in the range of shoulder flexion or elbow extension during reaching. None of the changes in kinematic outcome measures significantly correlated with any of the changes in SIS subscales. RTP integrating myoelectric bracing may be more beneficial than RTP only in improving self-reported function and perceptions of overall recovery. The authors observed no changes in the range of elbow extension, and no relationship between self-reported improvements and changes in reaching kinematics.

Muscle co-contraction during gait in individuals with articular cartilage defects in the knee.

Increased muscle co-contraction during gait is common in individuals with knee pathology, and worrisome as it is known to amplify tibiofemoral compressive forces. While knees with articular cartilage defects (ACD) are more vulnerable to compressive forces, muscle co-contraction has never been reported in this population. The purpose of this study was to evaluate the extent to which individuals with ACDs in the knee demonstrate elevated quadriceps to hamstrings muscle co-contraction on the involved limb during gait compared to the uninvolved limb and to healthy controls. We also explored the impact of participant characteristics and knee impairments on co-contraction. Twenty-nine individuals with full-thickness knee ACDs (ACD group) and 19 healthy adults (control group) participated in this study. Participants performed five gait trials at self-selected speed, during which activity of the quadriceps and hamstrings muscles were collected with surface electromyography. Three-dimensional motion capture was used to define phases of gait. Quadriceps strength and self-reported outcomes were also assessed in the same session. There were no differences in quadriceps: hamstrings co-contraction between the ACD and control groups, or between the involved and uninvolved limb for the ACD group. For both ACD and control groups, co-contraction was highest in early stance and lowest in late stance. Quadriceps strength was consistently the strongest predictor of muscle co-contraction in both the ACD and the control groups, with individuals with lower strength demonstrating greater co-contraction. Further study is needed to understand the effect of increased muscle co-contraction on joint compressive forces in the presence of varied quadriceps strength.

Stride Leg Ground Reaction Forces Predict Throwing Velocity in Adult Recreational Baseball Pitchers.

Ground reaction forces produced during baseball pitching have a significant impact in the development of ball velocity. However, the measurement of only one leg and small sample sizes in these studies curb the understanding of ground reaction forces as they relate to pitching. This study aimed to further clarify the role ground reaction forces play in developing pitching velocity. Eighteen former competitive baseball players with previous high school or collegiate pitching experience threw 15 fastballs from a pitcher's mound instrumented to measure ground reaction forces under both the drive and stride legs. Peak ground reaction forces were recorded during each phase of the pitching cycle, between peak knee height and ball release, in the medial/lateral, anterior/posterior, and vertical directions, and the peak resultant ground reaction force. Stride leg ground reaction forces during the arm-cocking and arm-acceleration phases were strongly correlated with ball velocity (r2 = 0.45-0.61), whereas drive leg ground reaction forces showed no significant correlations. Stepwise linear regression analysis found that peak stride leg ground reaction force during the arm-cocking phase was the best predictor of ball velocity (r2 = 0.61) among drive and stride leg ground reaction forces. This study demonstrates the importance of ground reaction force development in pitching, with stride leg forces being strongly predictive of ball velocity. Further research is needed to further clarify the role of ground reaction forces in pitching and to develop training programs designed to improve upper extremity mechanics and pitching performance through effective force development.

Validation of a method to accurately correct anterior superior iliac spine marker occlusion.

Anterior superior iliac spine (ASIS) marker occlusion commonly occurs during three-dimensional (3-D) motion capture of dynamic tasks with deep hip flexion. The purpose of this study was to validate a universal technique to correct ASIS occlusion. 420 ms of bilateral ASIS marker occlusion was simulated in fourteen drop vertical jump (DVJ) trials (n=14). Kinematic and kinetic hip data calculated for pelvic segments based on iliac crest (IC) marker and virtual ASIS (produced by our algorithm and a commercial virtual join) trajectories were compared to true ASIS marker tracking data. Root mean squared errors (RMSEs; mean±standard deviation) and intra-class correlations (ICCs) between pelvic tracking based on virtual ASIS trajectories filled by our algorithm and true ASIS position were 2.3±0.9° (ICC=0.982) flexion/extension, 0.8±0.2° (ICC=0.954) abduction/adduction for hip angles, and 0.40±0.17 N m (ICC=1.000) and 1.05±0.36 N m (ICC=0.998) for sagittal and frontal plane moments. RMSEs for IC pelvic tracking were 6.9±1.8° (ICC=0.888) flexion/extension, 0.8±0.3° (ICC=0.949) abduction/adduction for hip angles, and 0.31±0.13 N m (ICC=1.00) and 1.48±0.69 N m (ICC=0.996) for sagittal and frontal plane moments. Finally, the commercially-available virtual join demonstrated RMSEs of 4.4±1.5° (ICC=0.945) flexion/extension, 0.7±0.2° (ICC=0.972) abduction/adduction for hip angles, and 0.97±0.62 N m (ICC=1.000) and 1.49±0.67 N m (ICC=0.996) for sagittal and frontal plane moments. The presented algorithm exceeded the a priori ICC cutoff of 0.95 for excellent validity and is an acceptable tracking alternative. While ICCs for the commercially available virtual join did not exhibit excellent correlation, good validity was observed for all kinematics and kinetics. IC marker pelvic tracking is not a valid alternative.

Controversies surrounding quality measurement in colon and rectal surgery.

Quality improvement in health care has become a major topic of discussion among health care providers, patients, insurance companies, and the government. National Surgical Quality Improvement Project (NSQIP), along with a multitude of other programs, exists in an attempt to create objective data that can be used to compare hospitals and providers against a national average. Studies have shown that despite good patient care and proper surgical technique, patients who undergo procedures such as colectomy have a higher incidence of surgical site infection (SSI) and other morbidities. Therefore, hospitals with a large volume of colon and rectal surgery cases are routinely identified as "high outliers" in these quality improvement programs. Programs, such as NSQIP, may not be the best way to measure quality in specific subspecialties such as colon and rectal surgery.

Hip adductor activations during run-to-cut manoeuvres in compression shorts: implications for return to sport after groin injury.

Athletes at high risk of groin strains in sports such as hockey and soccer often choose to wear shorts with directional compression to aid in prevention of or recovery from hip adductor strains. Large, eccentric contractions are known to result in or exacerbate strain injuries, but it is unknown if these shorts have a beneficial effect on hip adductor muscle activity. In this study, surface electromyography (EMG) of the adductor longus and ground reaction force (GRF) data were obtained simultaneously on 29 healthy individuals without previous history of serious injury while performing unanticipated 45° run-to-cut manoeuvres in a laboratory setting wearing shorts with non-directional compression (control, HeatGear, Under Armour, USA) or shorts with directional compression (directional, CoreShort PRO, Under Armour, USA), in random order. Average adductor activity in the stance leg was significantly lower in the directional condition than in the control condition during all parts of stance phase (all P < 0.042). From this preliminary analysis, wearing directional compression shorts appears to be associated with reduced stance limb hip adductor activity. Athletes seeking to reduce demand on the hip adductors as they approach full return to activities may benefit from the use of directional compression shorts.

The effects of core muscle activation on dynamic trunk position and knee abduction moments: implications for ACL injury.

Anterior cruciate ligament (ACL) injury is one of the most common serious lower-extremity injuries experienced by athletes participating in field and court sports and often occurs during a sudden change in direction or pivot. Both lateral trunk positioning during cutting and peak external knee abduction moments have been associated with ACL injury risk, though it is not known how core muscle activation influences these variables. In this study, the association between core muscle pre-activation and trunk position as well as the association between core muscle pre-activation and peak knee abduction moment during an unanticipated run-to-cut maneuver were investigated in 46 uninjured individuals. Average co-contraction indices and percent differences between muscle pairs were calculated prior to initial contact for internal obliques, external obliques, and L5 extensors using surface electromyography. Outside tilt of the trunk was defined as positive when the trunk was angled away from the cutting direction. No significant associations were found between pre-activations of core muscles and outside tilt of the trunk. Greater average co-contraction index of the L5 extensors was associated with greater peak knee abduction moment (p=0.0107). Increased co-contraction of the L5 extensors before foot contact could influence peak knee abduction moment by stiffening the spine, limiting sagittal plane trunk flexion (a motion pattern previously linked to ACL injury risk) and upper body kinetic energy absorption by the core during weight acceptance.

Ipsilateral motor cortical responses to TMS during lengthening and shortening of the contralateral wrist flexors.

Unilateral lengthening contractions provide a greater stimulus for neuromuscular adaptation than shortening contractions in the active and non-active contralateral homologous muscle, although little is known of the potential mechanism. Here we examined the possibility that corticospinal and spinal excitability vary in a contraction-specific manner in the relaxed right flexor carpi radialis (FCR) when humans perform unilateral lengthening and shortening contractions of the left wrist flexors at the same absolute force. Corticospinal excitability in the relaxed right FCR increased more during lengthening than shortening at 80% and 100% of maximum voluntary contraction (MVC). Short-interval intracortical inhibition diminished during shortening contractions, and it became nearly abolished during lengthening. Intracortical facilitation lessened during shortening but increased during lengthening. Interhemispheric inhibition to the 'non-active' motor cortex diminished during shortening, and became nearly abolished during lengthening at 90% MVC. The amplitude of the Hoffman reflex in the relaxed right FCR decreased during and remained depressed for 20 s after lengthening and shortening of the left wrist flexors. We discuss the possibility that instead of the increased afferent input, differences in the descending motor command and activation of brain areas that link function of the motor cortices during muscle lengthening vs. shortening may cause the contraction-specific modulation of ipsilateral motor cortical output. In conclusion, ipsilateral motor cortex responses to transcranial magnetic stimulation are contraction-specific; unilateral lengthening and shortening contractions reduced contralateral spinal excitability, but uniquely modulated ipsilateral corticospinal excitability and the networks involved in intracortical and interhemispheric connections, which may have clinical implications.

CT colonography predictably overestimates colonic length and distance to polyps compared with optical colonoscopy.

OBJECTIVE: The purpose of this study was to determine the discrepancy between CT colonography (CTC) and optical colonoscopy (OC) measurements for both anus-to-cecum length and anus-to-polyps distance and then determine whether a conversion factor could be generated to equate these CTC and OC distances. MATERIALS AND METHODS: We retrospectively reviewed CTC and OC reports from patients who had undergone both procedures as part of an established protocol. The anus-to-cecum measurement recorded on a single proprietary CTC workstation was compared with the OC cecal length for each patient. Likewise, anus-to-polyp distances were compared as measured by the radiologist and endoscopist. RESULTS: Three hundred thirty-eight patients and 437 polyps were identified with complete data from both CTC and same-day OC. The average anus-to-cecum distance measured at CTC was 189 cm (range, 75-257 cm) and at OC, 108 cm (range, 65-150 cm). For polyps proximal to the splenic flexure (n = 145), the CTC anus-to-polyp measurement was on average 1.7 times that measured at OC. For left-sided polyps (n = 292), the CTC measurement was, on average, within 12 cm or 1.3 times that of the OC anus-to-polyp measurement. All the differences between CTC and OC measurements of cecal length and polyp distances were found to be statistically significant using a paired Student's t test of means (p < 0.001). CONCLUSION: Anus-to-cecum and anus-to-polyp distances are disparate but comparable using a conversion factor of 0.57 for the CTC anus-to-cecum measurement and 0.59 for right-sided CTC anus-to-polyp or 0.78 for left-sided CTC anus-to-polyp measurements. These anus-to-polyp conversion factors could potentially augment current CTC guidelines for accurate and precise polyp localization and removal at endoscopy.

Venous thromboembolic disease in colorectal patients.

Venous thromboembolic disease, which includes deep vein thromboses as well as pulmonary emboli, can be a significant complication in the postoperative patient. In particular, colorectal patients often carry a higher risk for venous thromboembolism when compared with patients undergoing other operative procedures. Features unique to colorectal patients are the high incidence of inflammatory bowel disease or malignancy. Typically, these patients will undergo lengthy pelvic procedures, which also contribute to a cumulative risk of venous thrombosis. It is critical that all patients and the proposed operative procedure are appropriately risk stratified. Risk stratification allows for easier implementation of an appropriate prophylactic strategy. There are a wide range of safe and effective mechanical and pharmacologic measures available. The authors provide very specific recommendations, but note that clinical judgment plays a significant role.