Outcome of acute hospital admission for non-specific low back pain: what is the role of MRI?

BACKGROUND: Low back pain is a common worldwide condition, affecting most people during their lifetime. Various imaging modalities are being used to assist clinicians in diagnosing and thus, aid in formulating a suitable management plan. Extensive research has been carried out in assessing this condition due to its high prevalence, with many guidelines published internationally. AIM: To determine whether MRI imaging influences the management of patients admitted with acute, non-specific low back pain between 1 January 2013 and 31 December 2015. METHOD: A total of 209 patients who met the inclusion criteria were included in the study. Suitable patients were initially identified from the ward admission book. Subsequently, relevant data regarding patient admission and management within the two-year period were obtained from the hospital patient management system, including radiology reports. RESULTS: Out of the 209 patients included in this study, 131 patients (63%) had an MRI as part of the diagnostic process. Most patients were managed non-operatively with only 41 (20%) out of the 209 patients having undergone acute surgery while an inpatient. In this subgroup, 38 had an MRI done prior to surgery. Among the 168 patients who were treated non-operatively, including epidural steroid injection, 13 patients (8%) had elective surgery within one year from their initial presentation. CONCLUSION: Use of MRI can aid in the early diagnosis and facilitate faster rehabilitation for patients. It can also potentially reduce patient stay in hospital and result in significant cost savings for the healthcare system. Imaging guidelines should be developed in the assessment of patients with low back pain in an acute hospital setting.

Movement Patterns of the Knee During Gait Following ACL Reconstruction: A Systematic Review and Meta-Analysis.

BACKGROUND: Altered gait patterns follow ing anterior cruciate ligament reconstruction (ACLR) may be associated with long-term impairments and post-traumatic osteoarthritis. OBJECTIVE: This systematic review and meta-analysis compared lower limb kinematics and kinetics of the ACL reconstructed knee with (1) the contralateral limb and (2) healthy age-matched participants during walking, stair climbing, and running. The secondary aim was to describe the differences over time following ACLR for these biomechanical variables. METHOD: Database searches were conducted from inception to July 2014 and updated in August 2015 for studies exploring peak knee angles and moments following ACLR during walking, stair negotiation, and running. Risk of bias was assessed with a modified Downs and Black quality index for all included studies, and meta-analyses were performed. Forest plots were explored qualitatively for recovery of gait variables over time after surgery. RESULTS: A total of 40 studies were included in the review; 26 of these were rated as low risk and 14 as high risk of bias. The meta-analysis included 27 studies. Strong to moderate evidence indicated no significant difference in peak flexion angles between ACLR and control groups during walking and stair ascent. Strong evidence was found for lower peak flexion moments in participants with ACLR compared with control groups and contralateral limb during walking and stair activities. Strong to moderate evidence was found for lower peak adduction moment in ACLR participants for the injured compared with the contralateral limbs during walking and stair descent. The qualitative assessment for recovery over time indicated a pattern towards restoration of peak knee flexion angle with increasing time from post-surgery. Peak knee adduction moments were lower within the first year following surgery and higher than controls during later phases (5 years). CONCLUSION: Joint kinematics are restored, on average, 6 years following reconstruction, while knee external flexion moments remain lower than controls. Knee adduction moments are lower during early phases following reconstruction, but are higher than controls, on average, 5 years post-surgery. Findings indicate that knee function is not fully restored following reconstruction, and long-term maintenance programs may be needed.

What is the best time point to identify patients at risk of developing persistent low back pain?

BACKGROUND: Early identification of patients at risk of developing persistent low back pain (LBP) is crucial. OBJECTIVE: Aim of this study was to identify in patients with a new episode of LBP the time point at which those at risk of developing persistent LBP can be best identified. METHODS: Prospective cohort study of 315 patients presenting to a health practitioner with a first episode of acute LBP. Primary outcome measure was functional limitation. Patients were assessed at baseline, three, six, twelve weeks and six months looking at factors of maladaptive cognition as potential predictors. Multivariate logistic regression analysis was performed for all time points. RESULTS: The best time point to predict the development of persistent LBP at six months was the twelve-week follow-up (sensitivity 78%; overall predictive value 90%). Cognitions assessed at first visit to a health practitioner were not predictive. CONCLUSIONS: Maladaptive cognitions at twelve weeks appear to be suitable predictors for a transition from acute to persistent LBP. Already three weeks after patients present to a health practitioner with acute LBP cognitions might influence the development of persistent LBP. Therefore, cognitive-behavioral interventions should be considered as early adjuvant LBP treatment in patients at risk of developing persistent LBP.

The deer femur--a morphological and biomechanical animal model of the human femur.

BACKGROUND: The need for continued refinement of animal models in orthopaedic studies persists despite decades of research. OBJECTIVE: This study investigates the merits of deer bone in comparison to the more commonly used pig and sheep bone as an animal model for the human femur. METHOD: A morphological and biomechanical comparison of deer, pig and sheep rear femurs to those of the human femur is presented. Morphological parameters measured include bone length, cortical and medullary diaphyseal diameters, cortical thickness, cortical cross-sectional area and bone density along the diaphysis. Biomechanical tests included whole-bone four-point flexure tests to determine the bending stiffness (N/mm), Young's modulus of bending (GPa), and ultimate strength in bending (MPa). In addition torsional stiffness (Nm/degree) as well as mid-diaphyseal cortical compressive elastic modulus (GPa) and strength (MPa) is investigated. RESULTS: On average, deer bone was found to be the least dissimilar from human femur. However, no single bone type consistently resembled the human femur. CONCLUSION: Deer femora should be considered a suitable animal model for the human femur.

Low back pain risk factors associated with persistence, recurrence and delayed presentation.

BACKGROUND: There is little knowledge in the literature on the role of time-related variables for the prognosis of acute and subacute low back pain (LBP). OBJECTIVE: The aim of this study was to estimate the relationship between time-related LBP characteristics and prognostic factors for acute/subacute LBP. METHODS: We performed a prospective inception cohort study of 315 patients attending a health practitioner for acute/subacute LBP or recurrent LBP. One-tailed correlations were conducted between patient characteristics and time-related variables. RESULTS: The pattern of correlation between risk factors for and resources against persistent LBP differed between three time-related variables. 'Subacute LBP' and 'delayed presentation' were positively associated with psychological factors. Both indicators were negatively correlated with resources against development of persistent LBP. Moreover, 'delayed presentation' was related positively with occupational stressors. In contrast, 'recurrent LBP' was only related to more impaired health-related factors. CONCLUSIONS: Patients with current LBP waiting longer until seeking help in primary care have a more disadvantageous profile of occupational and psychological risk factors and lower resource levels. A similar but less pronounced pattern occurred in those with subacute LBP compared to those with acute LBP. Consideration of time characteristics of LBP may help to better understand LBP.

Clothing increases the risk of indirect ballistic fractures.

BACKGROUND: Current literature has shown the mechanism of how indirect fractures occur but has not determined what factors increase the risks of such fractures. The objective of this study is thus to determine the effect of clothing and soft tissue thickness on the risk of indirect fracture formation. METHODS: Twenty-five fresh red deer femora embedded in ballistic gelatine were shot with varying distances off their medial cortex with a 5.56 × 45 mm North Atlantic Treaty Organization (NATO) bullet while being filmed with a slow-motion video. We compared the effect of two different gelatine depths and the effect of denim cloth laid onto the impact surface of the moulds. RESULTS: Bullet passage in thinner moulds failed to cause fracture because the bullet exited the mould before a large expanding temporary cavity was produced. Clothing dramatically altered the size and depth of the expanding cavity, as well as increased lateral pressures, resulting in more severe fractures with greater bullet distances from the bone that can cause fracture. CONCLUSIONS: Clothing increases the risk of indirect fracture and results in larger, more superficial temporary cavities, with greater lateral pressures than are seen in unclothed specimens, resulting in more comminuted fractures. Greater tissue depth affords the 5.56 × 45 mm NATO a chance to yaw and thus develop an enlarging temporary cavity that is sufficient to cause fracture.

Who is likely to develop persistent low back pain? A longitudinal analysis of prognostic occupational factors.

OBJECTIVE: Occupational low back pain (LBP) is considered to be the most expensive form of work disability, with the socioeconomic costs of persistent LBP exceeding the costs of acute and subacute LBP by far. This makes the early identification of patients at risk of developing persistent LBP essential, especially in working populations. The aim of the study was to evaluate both risk factors (for the development of persistent LBP) and protective factors (preventing the development of persistent LBP) in the same cohort. PARTICIPANTS: An inception cohort of 315 patients with acute to subacute or with recurrent LBP was recruited from 14 health practitioners (twelve general practitioners and two physiotherapists) across New Zealand. METHODS: Patients with persistent LBP at six-month follow-up were compared to patients with non-persistent LBP looking at occupational, psychological, biomedical and demographic/lifestyle predictors at baseline using multiple logistic regression analyses. All significant variables from the different domains were combined into a one predictor model. RESULTS: A final two-predictor model with an overall predictive value of 78% included social support at work (OR 0.67; 95%CI 0.45 to 0.99) and somatization (OR 1.08; 95%CI 1.01 to 1.15). CONCLUSIONS: Social support at work should be considered as a resource preventing the development of persistent LBP whereas somatization should be considered as a risk factor for the development of persistent LBP. Further studies are needed to determine if addressing these factors in workplace interventions for patients suffering from acute, subacute or recurrent LBP prevents subsequent development of persistent LBP.

Depression impacts the course of recovery in patients with acute low-back pain.

Little is known about the course of recovery of acute low back pain (LBP) patients as a function of depression. In a prospective study, 286 acute LBP patients were assessed at baseline and followed up over 6 months. Recovery was defined as improvement in the Oswestry Disability Index (ODI). Repeated-measures analysis of covariance was employed with ODI as repeated factor, age, sex, and body mass index as covariates, depression and all other potential prognostic factors as between-subject factors. Of study participants, 18% were classified as depressive (>33 points on the Zung Self-Rating Depression Scale). Of 286 participants, 135 were lost to follow-up. In the longitudinal sample of 151 patients the course of recovery was slower in depressive patients. Depression was associated with LBP especially after 6 weeks and should therefore be included in screening instruments for acute LBP patients to identify those at risk of delayed recovery at an early stage.

Bacterial contamination of unused, disposable non-sterile gloves on a hospital orthopaedic ward.

BACKGROUND: Non-sterile disposable gloves are used on large hospital wards, however their potential role as a vehicle for pathogen transmission has not been explored in this setting. AIMS: This study investigates glove use on a hospital orthopaedic ward to examine whether pathogen contamination occurs prior to contact with patients. METHOD: Glove samples were aseptically removed from boxes on a hospital orthopaedic ward on opening and days 3, 6 and 9 thereafter. Following elution of bacteria and viable counts, glove isolates were identified by standard techniques and 16s rDNA sequencing. Methicillin resistance of staphylococci was determined by disc diffusion, Epsilon tests and PCR. Gloves were inoculated to determine two isolate survival rates. RESULTS: Total bacterial counts ranged from 0 to 9.6 x 10(3) cfu/glove. Environmental bacteria, particularly Bacillus species, were present on 31/38 (81.6%) of samples. Half (19/38) the samples were contaminated with skin commensals; coagulase negative staphylococci were predominant. Enterococcus faecalis , Klebsiella pneumoniae , Pseudomonas sp. or methicillin susceptible Staphylococcus aureus were recovered from 5/38 (13.2%) of samples. Significantly more skin commensals and pathogens were recovered from samples from days 3, 6, 9 than box-opening samples. Staphylococcus epidermidis and Klebsiella pneumoniae inoculated onto gloves remained viable for several days but counts decreased. CONCLUSION: Health care workers introduced skin commensals and pathogenic bacteria into glove boxes indicating that unused, non-sterile gloves are potential pathogen transmission vehicles in hospitals. Findings highlight adherence to handwashing guidelines, common glove retrieval practice, and glove-box design as targets for decreasing bacteria transmission via gloves on hospital wards.

Remote ballistic fractures in a gelatine model--aetiology and surgical implications.

BACKGROUND: Remote ballistic femoral fractures are rare fractures reported in the literature but still debated as to their existence and, indeed, their treatment. This study aimed to prove their existence, understand how they occur and determine which ammunition provides the greatest threat. In addition, fracture patterns, soft tissue disruption and contamination were assessed to aid in treatment planning. METHOD: We filmed 42 deer femora embedded in ballistic gelatine and shot with four different military (5.56 × 45 mm, 7.62 × 39 mm) and civilian (9 × 19 mm, .44 in.) bullets, at varying distances off the bone (0-10 cm). RESULTS: Two remote ballistic fractures occurred, both with .44 in. hollow-point bullets shot 3 cm off the bone. These fractures occurred when the leading edge of the expanding temporary cavity impacted the femur's supracondylar region, producing a wedge-shaped fracture with an undisplaced limb, deceivingly giving the appearance of a spiral fracture. No communication was seen between the fracture and permanent cavity, despite the temporary cavity encasing the fracture and stripping periosteum from its base. CONCLUSION: These fractures occur with civilian ammunition, but cannot prove their existence with military rounds. They result from the expanding temporary cavity affecting the weakest part of the bone, creating a potentially contaminated wedge-shaped fracture, important for surgeons considering operative intervention.

Occupational, personal and psychosocial resources for preventing persistent low back pain.

The aim of this prospective cohort study was to identify modifiable protective factors of the progression of acute/subacute low back pain (LBP) to the persistent state at an early stage to reduce the socioeconomic burden of persistent LBP. Patients attending a health practitioner for acute/subacute LBP were assessed at baseline addressing occupational, personal and psychosocial factors, and followed up over 12 weeks. Pearson correlations were calculated between these baseline factors and the presence of nonpersistent LBP at 12-week follow-up. For those factors found to be significant, multivariate logistic regression analyses were performed. The final 3-predictor model included job satisfaction, mental health and social support. The accuracy of the model was 72%, with 81% of nonpersistent and 60% of persistent LBP patients correctly identified. Further research is necessary to confirm the role of different types of social support regarding their prognostic influence on the development of persistent LBP.

Prognostic occupational factors for persistent low back pain in primary care.

PURPOSE: To reduce the socio-economic burden of persistent low back pain (LBP), factors influencing the progression of acute/subacute LBP to the persistent state must be identified at an early stage. METHODS: Prospective inception cohort study of patients attending a health practitioner for their first episode of acute/subacute or recurrent LBP. Patients were assessed at baseline addressing occupational, psychological, biomedical and demographic/lifestyle factors and followed up over 6 months. Multivariate logistic regression analysis was performed separately for the variables groups of the four different domains, controlling for age, gender and body mass index. The overall predictive value was calculated for the full regression models of the different domains. Finally, all significant variables from the different domains were combined into a final predictor model. RESULTS: The final four-predictor model predicted 51 % of variance of persistent LBP and included 'resigned attitude towards the job' (OR 1.73; 95 % CI 1.16-2.59), 'social support at work' (OR 0.54; 95 % CI 0.32-0.90), 'functional limitation' (OR 1.05; 95 % CI 1.01-1.10) and 'duration of LBP' (OR 1.04; 95 % CI 1.02-1.06). The accuracy of the model was 83 %, with 92 % of non-persistent and 67 % of persistent LBP patients correctly identified. CONCLUSIONS: In this study of patients with acute/subacute LBP, 'resigned attitude towards the job' increased the likelihood of persistent LBP at 6 month. Addressing this factor with workplace interventions has the potential to modify the outcome. In patients experiencing 'social support at work', the development of persistent LBP was less likely and might therefore be considered as potential resource for prevention of persistent LBP.

Thigh pain--an unusual presentation of ruptured appendicitis.

We present a case in a 56-year-old female with a perforated retrocaecal appendicitis presenting as a large right thigh abscess. We discuss the diagnosis and treatment and the importance to refer early to a general surgeon if suspected.

Predictors of sickness absence in patients with a new episode of low back pain in primary care.

This study examines predictors of sickness absence in patients presenting to a health practitioner with acute/ subacute low back pain (LBP). Aims of this study were to identify baseline-variables that detect patients with a new LBP episode at risk of sickness absence and to identify prognostic models for sickness absence at different time points after initial presentation. Prospective cohort study investigating 310 patients presenting to a health practitioner with a new episode of LBP at baseline, three-, six-, twelve-week and six-month follow-up, addressing work-related, psychological and biomedical factors. Multivariate logistic regression analysis was performed to identify baseline-predictors of sickness absence at different time points. Prognostic models comprised 'job control', 'depression' and 'functional limitation' as predictive baseline-factors of sickness absence at three and six-week follow-up with 'job control' being the best single predictor (OR 0.47; 95%CI 0.26-0.87). The six-week model explained 47% of variance of sickness absence at six-week follow-up (p<0.001). The prediction of sickness absence beyond six-weeks is limited, and health practitioners should re-assess patients at six weeks, especially if they have previously been identified as at risk of sickness absence. This would allow timely intervention with measures designed to reduce the likelihood of prolonged sickness absence.

Interventions for treating acute elbow dislocations in adults.

BACKGROUND: Dislocation of the elbow joint is a relatively uncommon injury. OBJECTIVES: To assess the effects of various forms of treatment for acute simple elbow dislocations in adults. SEARCH METHODS: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (April 2011), the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2011 Issue 1), MEDLINE (1948 to March Week 5 2011), EMBASE (1980 to 2011 Week 14), PEDro (April 2011), CINAHL (April 2011), various trial registers, various conference proceedings and bibliographies of relevant articles. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials of conservative and surgical treatment of dislocations of the elbow in adults. Excluded were trials involving dislocations with associated fractures, except for avulsion fractures. DATA COLLECTION AND ANALYSIS: Data extraction and assessment of risk of bias were independently performed by two review authors. There was no pooling of data. MAIN RESULTS: Two small randomised controlled trials, involving a total of 80 participants with simple elbow dislocations, were included. Both trials were methodologically flawed and potentially biased.One trial, involving 50 participants, compared early mobilisation at three days post reduction versus cast immobilisation. At one year follow-up, the recovery of range of motion appeared better in the early mobilisation group (e.g. participants with incomplete recovery of extension: 1/24 versus 5/26; risk ratio 0.22, 95% confidence interval 0.03 to 1.72). However, the results were not statistically significant. There were no reports of instability or recurrence. One person in each group had residual pain at one year.The other trial, involving 30 participants, compared surgical repair of the torn ligaments versus conservative treatment (cast immobilisation for two weeks). At final follow-up (mean 27.5 months), there were no statistically significant differences between the two groups in the numbers of patients who considered their injured elbow to be inferior to their non-injured elbow (10/14 versus 7/14; RR 1.43, 95% CI 0.77 to 2.66) or in other patient complaints about their elbow such as weakness, pain or weather-related discomfort. There were no reports of instability or recurrence. There were no statistically significant differences between the two groups in range of motion of the elbow (extension, flexion, pronation, and supination) or grip strength at follow-up. No participants had neurological disturbances of the hand but two surgical group participants had recurrent dislocation of the ulnar nerve (no other details provided). One person in each group had radiologically detected myositis ossificans (bone formation within muscles following injury). AUTHORS' CONCLUSIONS: There is insufficient evidence from randomised controlled trials to determine which method of treatment is the most appropriate for simple dislocations of the elbow in adults. Although weak and inconclusive, the available evidence from a trial comparing surgery versus conservative treatment does not suggest that the surgical repair of elbow ligaments for simple elbow dislocation improves long-term function. Future research should focus on questions relating to non-surgical treatment, such as the duration of immobilisation.

WITHDRAWN: Rehabilitation after surgery for flexor tendon injuries in the hand.

BACKGROUND: Postoperative rehabilitation of the flexor tendons in the hand consists of a short period of immobilisation while pain and swelling diminish, followed by progressive mobilisation to maximize the range of motion of the affected fingers. By altering the time of immobilisation and the manner of subsequent mobilisation different rehabilitation regimes are created. OBJECTIVES: To determine, with evidence from randomised controlled trials, the optimal rehabilitation strategy after surgery for flexor tendon injuries in the hand. SEARCH STRATEGY: We searched the Cochrane Bone, Joint and Muscle Trauma Group specialised register (November 2002), the Cochrane Central Register of Controlled Trials (The Cochrane Library, issue 4, 2002), MEDLINE (1966 to November 2002), EMBASE (1988 to November 2002), CINAHL (1982 to October 2002), CURRENT CONTENTS (1993 to October 2002), PEDro - The Physiotherapy Evidence Database (http://ptwww.cchs.usyd.edu.au/pedro/ accessed 30/10/2002) and reference lists of articles. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials of interventions for rehabilitation after surgery of flexor tendon injuries in the hand after surgery. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality, using a 10 item scale, and extracted data where possible. Additional information was sought from trialists when required. Due to the lack of extractable data and the variety of interventions used, pooling was not attempted. Where possible relative risks and 95 per cent confidence intervals were calculated for dichotomous outcomes, and mean differences and 95 per cent confidence intervals calculated for continuous outcomes. MAIN RESULTS: Six trials, including three reported only in abstracts, with a total of 464 participants were included. Data were not pooled. One trial compared continuous passive motion (CPM) with controlled intermittent passive motion (CIPM) and found a significant difference in mean active motion favouring CPM (WMD 19.00 degrees, 95% CI 15.11 to 22.89). One trial compared a shortened passive flexion/active extension programme with a normal passive flexion/active extension mobilisation programme, and reported (without data) a significant reduction in absence from work of 2.1 weeks in favour of the shortened programme. Other trials compared active flexion with rubber band traction, early controlled active mobilisation with early controlled passive mobilisation and dynamic splintage versus static splintage. No trials found significant differences in overall functioning or complication rate. AUTHORS' CONCLUSIONS: Controlled mobilisation regimens are widely employed in rehabilitation after flexor tendon repair in the hand. This review found insufficient evidence from randomised controlled trials to define the best mobilisation strategy.

Patterns of lower limb fractures sustained during snowsports in Otago, New Zealand.

AIMS: The aim of this study was to determine the nature and circumstances of lower limb fractures caused by skiing and snowboarding at the Otago skifields that required operative treatment at Dunedin Hospital from 2002 to 2008. METHODS: Patients were retrospectively identified from clinical records. RESULTS: 108 cases were included in the study; 28 snowboarders and 80 skiers. Snowboarders had more fractures involving the ankle whereas skiers had more fractures of the proximal third of the tibia and fibula. Snowboarders were more likely to fracture the fibula compared to skiers. Nearly two-thirds of fractures in snowboarders were to the left limb whereas in skiers a laterality was not demonstrated. Most fractures were the result of falls but a greater proportion of snowboarders had jump-related injuries. CONCLUSIONS: Snowboarding related lower limb fractures are more likely to involve the ankle and be left sided. Skiing related lower limb fractures are more proximal with no laterality.

Nerve root sedimentation sign: evaluation of a new radiological sign in lumbar spinal stenosis.

STUDY DESIGN: Retrospective case-referent study. OBJECTIVE: To assess whether the new sedimentation sign discriminates between nonspecific low back pain (LBP) and symptomatic lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA: In the diagnosis of LSS, radiologic findings do not always correlate with clinical symptoms, and additional diagnostic signs are needed. In patients without LSS, we observe the sedimentation of lumbar nerve roots to the dorsal part of the dural sac on supine magnetic resonance image scans. In patients with symptomatic and morphologic central LSS, this sedimentation is rarely seen. We named this phenomenon "sedimentation sign" and defined the absence of sedimenting nerve roots as positive sedimentation sign for the diagnosis of LSS. METHODS: This study included 200 patients. Patients in the LSS group (n = 100) showed claudication with or without LBP and leg pain, a cross-sectional area <80 mm, and a walking distance <200 m; patients in the LBP group (n = 100) had LBP, no leg pain, no claudication, a cross-sectional area of the dural sac >120 mm, and a walking distance >1000 m. The frequency of a positive sedimentation sign was compared between the 2 groups, and intraobserver and interobserver reliability were assessed in a random subsample (n = 20). RESULTS: A positive sedimentation sign was identified in 94 patients in the LSS group (94%; 95% confidence interval, 90%-99%) but none in the LBP group (0%; 95% confidence interval, 0%-4%). Reliability was kappa = 1.0 (intraobserver) and kappa = 0.93 (interobserver), respectively. There was no difference in the detection of the sign between segmental levels L1-L5 in the LSS group. CONCLUSION: A positive sedimentation sign exclusively and reliably occurs in patients with LSS, suggesting its usefulness in clinical practice. Future accuracy studies will address its sensitivity and specificity. If they confirm the sign's high specificity, a positive sedimentation sign can rule in LSS, and, with a high sensitivity, a negative sedimentation sign can rule out LSS.