[120-day follow-up after proximal femoral fractures-first results from the Geriatric Trauma Registry DGU®]. / 120-Tage-Follow-up nach hüftgelenknahen Frakturen ­ erste Daten aus dem AltersTraumaRegister DGU®.

BACKGROUND: Geriatric trauma centers which are certified to the status of a Geriatic Trauma Center DGU® based on the criteria catalogue as outlined by the German Trauma Society (DGU), are required to participate in the Geriatric Trauma Register (ATR-DGU) for quality management and outcome analyses. The evaluation is pseudoanonymous and includes data on all treated hip fracture patients over 70 years old. This has been in regular use since 2016. This study analyzed the postoperative evaluation of gait, mortality, quality of life, hospital readmission and treatment of osteoporosis after 120 days. METHODS: A voluntary retrospective data evaluation of the ATR-DGU 120-day follow-up from 2017 was carried out. Written consent for the analysis and publication of the data was obtained from six clinics that already participated in the follow-up. The primary target parameters were mortality rate, readmission and revision rates, gait quality, osteoporosis treatment and quality of life according to EQ-5D-3L. The patient data were completely pseudonymized and a descriptive analysis was carried out. RESULTS: In this study 957 patients from the 6 hospitals were included. The average age was 84.5 years (±6.8 years). The mortality rate during the acute treatment phase was 5%. The 120-day follow-up could be evaluated in 412 patients, 10% of these required hospital readmission due to complications oft he same fracture and of these 6% required revision surgery. The mortality rate at 120 days was 12%. In 54% of the patients the fracture led to deterioration of mobility and 49% of patients received osteoporosis treatment after 120 days. The results of the EQ-5D-3L at 120 days revealed improvement as compared to the values on postoperative day 7; however, the preoperative status with respect to mobility and quality of life could not be regained. CONCLUSION: Despite the clear advantages of interdisciplinary treatment, the results are still limited concerning mobilization and quality of life. Further analysis of causative and influencing factors is necessary.

[Results of the pilot phase of the Age Trauma Registry DGU®]. / Ergebnisse der Pilotphase des AltersTraumaRegister DGU®.

BACKGROUND: Since 2014, hospitals with ortho-geriatric fracture centres could be certified as AltersTraumaZentrum DGU® in Germany. To measure the quality of treatment in these centres, a geriatric trauma registry (AltersTraumaRegister DGU®) was established. OBJECTIVES: The aim of this work was to report the results of the pilot phase of the AltersTraumaRegister DGU® from the year 2015. MATERIALS AND METHODS: Included were 118 patients >70 years with hip fracture or implant-related femoral fractures. Apart from other parameters, the point of surgery, initiation of anti-osteoporotic treatment and the EQ-5D one week post-surgery was measured. RESULTS: Surgery was performed in 87% of patients within 24 h. Specific osteoporotic therapy could be increased from 4 to 63 patients. The EQ-5D was strongly restricted to one week post-surgery. CONCLUSION: Based on the timing of surgery and anti-osteoporotic therapy, the treatment seems to be successful in the ortho-geriatric fracture centres. For a better evaluation of treatment quality in the AltersTraumaZentren DGU®, implementation of follow-up examinations in the AltersTraumaRegister DGU® is essential.

The Association Between Orthogeriatric Co-Management and Mortality Following Hip Fracture.

BACKGROUND: To meet the special needs of older patients with fragility fractures, models for collaborative orthogeriatric care have been developed. The objective of our study was to analyze the association of orthogeriatric co-management with mortality following hip fracture in older patients in Germany. METHODS: This observational study was based on health insurance claims data from 58 001 patients (79.4% women) aged ≥80 years admitted to the hospital with hip fracture between January 2014 and March 2016. They were treated in 828 German hospitals with or without orthogeriatric co-management. The outcome measure was cumulative mortality with adjustment of the regression analyses. RESULTS: The crude 30-day mortality was 10.3% for patients from hospitals with orthogeriatric co-management and 13.4% for patients from hospitals without orthogeriatric co-management. The adjusted 30-day mortality was 22% lower for patients in hospitals with orthogeriatric co-management (rate ratio 0.78; 95% CI [0.74; 0.82]; adjusted absolute difference -2.48%; 95% CI [-2.98; -1.98]). The difference in 30-day mortality remained nearly unchanged over the first 6 months. The risk reduction with orthogeriatric co-management was consistently observed in both women and men, across age groups, and in patients with and without care needs. The mean length of the index stay was 19.8 days in hospitals with orthogeriatric co-management and 14.4 days in hospitals without orthogeriatric co-management. CONCLUSION: A multidisciplinary orthogeriatric approach is associated with lower mortality and a longer index stay in hospital after hip fracture.

Postural control deficit in acute QTF grade II whiplash injuries.

STUDY DESIGN: Experimental in vivo study. OBJECTIVE: The objective was to investigate the balance control in patients with acute QTF grade II whiplash injuries of the cervical spine. SUMMARY OF BACKGROUND DATA: Tetra-ataxiametric posturography in chronic pain patients after whiplash injuries of the cervical spine has revealed an impaired regulation of balance. However, so far it is unclear if this is caused by the accident or other factors that are associated with the pain chronification process. METHODS: 40 patients with acute QTF grade II whiplash injuries and 40 healthy matched controls were examined on a posturography platform. The stability index ST(Sigma) and the Fourier analysis FA(Sigma) (0.10-1.00Hz) were established for eight standing positions and sum scores were calculated. The pain index was established using a visual analog scale ranging from 0 to 100. A follow-up examination was conducted for the patients after 2 months. RESULTS: The patients with acute whiplash injuries of the cervical spine achieved significantly poorer results for both ST(Sigma) and FA(Sigma) than the healthy controls. There were no differences between the eight standing positions for both ST(Sigma) and FA(Sigma). After 2 months, 17 patients had no change in the pain development, 21 patients showed an improvement in pain intensity and 2 patients had deteriorated. The subgroup of patients with improvement in pain intensity showed a significant improvement in balance control concerning the FA(Sigma) compared to patients with unchanged pain intensity. CONCLUSION: Patients with acute whiplash injuries have a reduced balance control as compared to matched controls. This study gives an indication that post-traumatic neck pain is associated with impairments of postural control.

[Refresher Orthogeriatrics]. / Orthogeriatrie.

Fragility fractures are associated with a substantial mortality and morbidity. Because of the high prevalence of comorbidities and a high risk of complications the application of geriatric principles in the complex treatment of these patients is vital. The last years have seen a paradigm shift in the treatment of fragility fractures from an orthopedic disorder towards an orthogeriatric syndrome. This article reviews the orthogeriatric principles of treating fragility fractures.

Injuries of the cervical spine in patients with ankylosing spondylitis: experience at two trauma centers.

OBJECT: The cervical spine in a patient with ankylosing spondylitis (AS) (Bechterew disease) is exposed to maximal risk due to physical load. Even minor trauma can cause fractures because of the spine's poor elasticity (so-called bamboo spine). The authors conducted a study to determine the characteristics of cervical fractures in patients with AS to describe the standard procedures in the treatment of this condition at two trauma centers and to discuss complications of and outcomes after treatment. METHODS: Between 1990 and 2006, 37 patients were surgically treated at two institutions. All patients were examined preoperatively and when being discharged from the hospital for rehabilitation. Single-session (11 cases) and two-session anterior-posterior (13 cases), anterior (11 cases), posterior (two cases), and laminectomy (one case) procedures were performed. The injury pattern, segments involved, the pre- and postoperative neurological status, and complications were analyzed. Preoperative neurological deficits were present in 36 patients. All patients experienced improvement postoperatively, and there was no case of surgery-related neurological deterioration. In patients in whom treatment was delayed because of late diagnosis, preoperative neurological deficits were more severe and improvement worse than those treated earlier. The causes of three deaths were respiratory distress syndrome due to a rigid thorax and cerebral ischemia due to rupture of the vertebral arteries. There were 12 perioperative complications (32%), three infections, one deep venous thrombosis, five early implant failures, and the three aforementioned fatalities. There were no cases of epidural hematoma. In all five cases in which early implant failure required revision surgery, the initial stabilization procedure had been anterior only. A comparison of complications and the outcomes at the two centers revealed no significant differences. CONCLUSIONS: The standard intervention for these injuries is open reduction, anterior decompression and fusion, and anterior-posterior stabilization; these procedures may be conducted in one or two stages. Based on the early implant failures that occurred exclusively after single-session anterior stabilizations (five of 10--a failure rate of 50%), the authors have performed only posterior and anterior procedures since 1997 at both centers. Diagnostic investigations include computed tomography scanning or magnetic resonance imaging of the whole spine, because additional injuries are common. The causative trauma may be very slight, and diagnosis may be delayed because plain radiographs can be initially misinterpreted. In cases in which diagnosis is delayed, patients present with more severe neurological deficits, and postoperative improvement is less pronounced than that in patients in whom a prompt diagnosis is established. Because of postoperative pulmonary and ischemic complications, the mortality rate is high. In the present series the mortality rate was lower than the mean rate reported in the literature.

Metachronous and multiple aneurysmal bone cysts: a rare variant of primary aneurysmal bone cysts.

In 1942, Jaffe and Lichtenstein introduced the term aneurysmal bone cyst (ABC). Primary ABC is characterized by the presence of spongy or multi-cameral cystic tissue filled with blood. The process is benign, but it is locally destructive and has a high propensity for recurrence. In this paper, we present the third case of multiple metachronous primary ABCs as a rare variant of ABC. We describe the 10-year history of a 12-year-old boy with metachronous multiple primary ABCs at five different sites (right proximal humerus, right ulna, bilateral distal radius and right lateral clavicle). Furthermore, our patient suffered from vascular malformations, such as aortic isthmus stenosis, hypoplastic thoraco-abdominal aorta and bilateral renal artery stenosis. To date, in contrast to solitary ABC, the multiple lesions have been found more frequently in male individuals. Using interphase cytogenetics, we analyzed three of five of the patient's ABCs and one of these was also analyzed by GTG-banding. No chromosomal abnormalities were found. Significantly, we excluded the missense mutation of codon 201 in guanine nucleotide-binding protein 1 gene consistently found in McCune-Albright syndrome (MAS) and in non-MAS cases of polyostotic fibrous dysplasia of bone with or without secondary ABC.

Enhanced primary stability through additional cementable cannulated rescue screw for anterior thoracolumbar plate application.

OBJECT: The authors conducted a study to investigate the biomechanical in vitro influence of a new anchorage system for fixation of anterior stabilization devices and the possibility of using additional cement after screw insertion to compensate for poor bone quality. The incidence of osteoporosis-related fractures has increased nearly twofold in the last decade. Because of problems associated with anterior screw fixation such as loosening, mechanical failure, and the weakness of osteoporotic bone, current surgical treatments of vertebral body (VB) fractures are problematic. This is due to poor fixation strength of anterior screws in the adjacent segments. The aim of this study was to determine whether a new cemented and uncemented VB screw provides improved primary stability following placement of anterior instrumentation in cases of fracture. METHODS: The primary stability-related parameters of a new uncemented/cemented screw were compared with those of conventional monocortical screw fixation in a burst fracture model in which strut graft and anterior overbridging instrumentation were used. The use of the new uncemented screw improved the range of motion (ROM) of the stabilized spine in flexion-extension by approximately 22%, in rotation by 20%, and in lateral bending by 15%. Additional cementation improved the ROM by approximately 41% in flexion-extension, 32% in rotation, and 30% in lateral bending compared with conventional monocortical screw fixation. CONCLUSIONS: The new cannulated screw improves fixation strength and primary stability parameters. It is useful in the initial treatment of fractures in cases of poor bone quality and as a rescue device if previously inserted screws do not remain securely in place.

Axial compression force measurement acting across the strut graft in thoracolumbar instrumentation testing.

OBJECTIVE: Current recommendations for spinal implant testing do not consider the determination of axial compression forces of the overbridging implant on the strut graft. No direct data exist on the influence of load transfer through the strut graft and of the kind of instrumentation, especially in thoracolumbar corpectomy models. DESIGN: Therefore in this biomechanical in vitro study a method for measurement of the axial compression force acting across the strut graft in different thoracolumbar instrumentations was developed. METHODS: In this in vitro study, a corpectomy model was simulated and anterior, posterior and combined short fixation devices currently available were tested under pure moments to evaluate their biomechanical stabilizing characteristics. Range of motion, neutral zone and the axial compressive force acting on the strut graft were measured continuously in the three primary directions. RESULTS: Without loads, the combined stabilization and followed by anterior instrumentation created a higher axial compression force than the dorsal instrumentation on the strut graft. Especially during maximal extension there was no axial compression of the dorsal instrumentation on the strut graft, which resulted in an increase of the range of motion. CONCLUSION: The feasibility of the new method was demonstrated in this study. For the purpose of standardization and comparison it should be considered in spinal implant testing.

Molecular profiling of chordoma.

The molecular basis of chordoma is still poorly understood, particularly with respect to differentially expressed genes involved in the primary origin of chordoma. In this study, therefore, we compared the transcriptional expression profile of one sacral chordoma recurrence, two chordoma cell lines (U-CH1 and U-CH2) and one chondrosarcoma cell line (U-CS2) with vertebral disc using a high-density oligonucleotide array. The expression of 65 genes whose mRNA levels differed significantly (p<0.001; ≥6-fold change) between chordoma and control (vertebral disc) was identified. Genes with increased expression in chordoma compared to control and chondrosarcoma were most frequently located on chromosomes 2 (11%), 5 (8%), 1 and 7 (each 6%), whereas interphase cytogenetics of 33 chordomas demonstrated gains of chromosomal material most prevalent on 7q (42%), 12q (21%), 17q (21%), 20q (27%) and 22q (21%). The microarray data were confirmed for selected genes by quantitative polymerase chain reaction analysis. As in other studies, we showed the expression of brachyury. We demonstrate the expression of new potential candidates for chordoma tumorigenesis, such as CD24, ECRG4, RARRES2, IGFBP2, RAP1, HAI2, RAB38, osteopontin, GalNAc-T3, VAMP8 and others. Thus, we identified and validated a set of interesting candidate genes whose differential expression likely plays a role in chordoma.

Early orthogeriatric treatment of trauma in the elderly: a systematic review and metaanalysis.

BACKGROUND: More than 125,000 hip fractures occur in Germany every year, with a one-year mortality of about 25%. To improve treatment outcomes, models of cooperation between trauma surgery and geriatrics have been developed. Their benefit has not yet been unequivocally demonstrated. METHODS: We systematically searched the Medline database and the Cochrane Library for prospective randomized controlled trials in which the treatment of elderly patients with fractures by the trauma surgery service alone was compared with preoperatively initiated collaborative treatment by the trauma surgery and geriatric services ("orthogeriatric" treatment). We investigated three treatment outcome variables--length of hospital stay, in-hospital mortality, and one-year mortality--in a metaanalysis. RESULTS: The five trials of hip fracture treatment that met the selection criteria all had relatively small study populations and a high risk of bias. The outcomes with respect to hospital stay differed greatly among trials (I(2): 88.5%), and geriatric intervention was not found to have any statistically significant effect (0.06 days, 95% confidence interval [CI]: -3.74 to 3.62 days). The relative risk of dying in the hospital was 0.66 for orthogeriatric treatment (95% CI: 0.28-1.55, p = 0.34), and the hazard ratio for one-year mortality was 0.79 in favor of orthogeriatric treatment (95% CI: 0.57 to 1.10, p = 0.17). A metaanalysis of functional outcomes was not possible. CONCLUSION: Only a few randomized controlled trials of early orthogeriatric treatment have been performed, and these trials are of limited quality. Due to low case numbers, a benefit from interdisciplinary orthogeriatric treatment could not clearly be demonstrated. Further trials are needed.

Diversity of patients microflora on orthopaedic and dental implants.

The aim of this study was to compare the diversity of microbial colonization on implant material from different individuals. Eubacterial DNA was extracted, separated and sequenced from orthopaedic metallic implant material, tissues or body fluids, and skin of 4 patients as well as from identical dental cement material from 10 individuals after revision and routine removal. Additionally, the composition of the bacterial population of the dental cement and the oral swab sample from one individual after direct extraction of bacterial DNA was compared to extraction after conventional microbiological enrichment. The latter investigation proved that the commonly used cultivation technique gave different results than direct extraction of DNA, especially as regards the detection of anaerobes. Comparing the bacterial colonization of implant materials from different patients showed significant individual diversity. The common focus on a constricted pathogen spectrum may have to be expanded toward a multispecies population. Moreover, the dependence of the bacterial population on the individual host has to be integrated in discussing implant colonization and infection.

Bacterial DNA from orthopedic implants after routine removal.

Bacterial 16S rDNA was monitored and identified from orthopedic metallic implants after routine or septic removal from patients in a German hospital. From March to June 2009, 28 metallic implants, 10 human biopsies, and 6 foam dressings from 28 patients were investigated. After analysis of this first collective, the methods were optimized to enhance sensitivity and to reduce interference with human DNA. Then a second collective consisting of 21 metallic implants from 21 patients was investigated from June 2009 to January 2010. In the first collective, 71% of the metallic implants were negative for eubacterial DNA. Pathogens such as Staphylococcus aureus and opportunists such as Lactobacillus rhamnosus were identified in 11% of the samples, whereas the residual 18% positive results were classified as from skin sources or could not be confirmed. Tissue, secretion, and bone samples as well as foam dressings from the same collective also contained pathogens and opportunists. After the optimization of the methods, a considerable increase of positive samples was seen: in the second collective 19 of the 21 metallic implants proved to be positive for eubacterial 16S rDNA. Bacterial DNA from environmental sources was detected in 13 samples, and in 20 specimens, predominantly mostly the skin. Opportunistic pathogens were detected in 19 samples. Interestingly, septic complications did not occur despite the presence of bacterial DNA. The results obtained up to now encourage us not only to continue a directed monitoring of bacterial DNA on orthopedic implants in practice but also to look intensely for possible sources of bacterial contamination during and after insertion or during removal of such implants.

Deceleration during 'real life' motor vehicle collisions - a sensitive predictor for the risk of sustaining a cervical spine injury?

BACKGROUND: The predictive value of trauma impact for the severity of whiplash injuries has mainly been investigated in sled- and crash-test studies. However, very little data exist for real-life accidents. Therefore, the predictive value of the trauma impact as assessed by the change in velocity of the car due to the collision (DeltaV) for the resulting cervical spine injuries were investigated in 57 cases after real-life car accidents. METHODS: DeltaV was determined for every car and clinical findings related to the cervical spine were assessed and classified according to the Quebec Task Force (QTF). RESULTS: In our study, 32 (56%) subjects did not complain about symptoms and were therefore classified as QTF grade 0; 25 (44%) patients complained of neck pain: 8 (14%) were classified as QTF grade I, 6 (10%) as QTF grade II, and 11 (19%) as QTF grade IV. Only a slight correlation (r = 0.55) was found between the reported pain and DeltaV. No relevant correlation was found between DeltaV and the neck disability index (r = 0.46) and between DeltaV and the QTF grade (r = 0.45) for any of the collision types. There was no DeltaV threshold associated with acceptable sensitivity and specificity for the prognosis of a cervical spine injury. CONCLUSION: The results of this study indicate that DeltaV is not a conclusive predictor for cervical spine injury in real-life motor vehicle accidents. This is of importance for surgeons involved in medicolegal expertise jobs as well as patients who suffer from whiplash-associated disorders (WADs) after motor vehicle accidents. TRIAL REGISTRATION: The study complied with applicable German law and with the principles of the Helsinki Declaration and was approved by the institutional ethics commission.

Biomechanical in vitro comparison of different mono- and bisegmental anterior procedures with regard to the strategy for fracture stabilisation using minimally invasive techniques.

Endoscopic minimally invasive techniques have become an established method of fracture stabilisation in the spine. In view of this fact, anterior stabilisation strategies must be reconsidered, as monosegmental A 3.1 compression fractures are increasingly being stabilised endoscopically from the anterior aspect using minimally invasive techniques. This study investigated the biomechanical necessity of anterior two-point or four-point stabilisation in the instrumentation of mono- and bisegmental fractures. In three biomechanical in vitro studies, burst fracture stabilisation was simulated, and anterior short fixation devices were tested under load with pure moments up to 3.75 Nm to evaluate the biomechanical stabilising characteristics of different kinds of instrumentations in flexion/extension, lateral bending, and axial rotation. Only anterior four-point stabilisation resulted in sufficient primary stability both in mono- and bisegmental instrumentation and therefore represents the standard procedure in open as well as in minimally invasive spinal surgery.

Comparison of the relative benefits of 2 versus 10 days of soft collar cervical immobilization after acute whiplash injury.

OBJECTIVE: To investigate the effects of 2-day and 10-day immobilization of the cervical spine on pain, range of motion (ROM), and disability of patients with Quebec Task Force (QTF) grade II whiplash injuries. DESIGN: Randomized controlled trial. SETTING: University hospital emergency department. PARTICIPANTS: Seventy patients with acute QTF grade II whiplash injuries. INTERVENTIONS: At the intake examination within 24 hours after the whiplash trauma, the patients were randomized to 2 therapy groups (2-d or 10-d immobilization with a soft cervical collar). All patients received pain drugs (nonsteroidal anti-inflammatory drugs) and after 7 days, all patients started a standardized physiotherapy program 2 to 3 times a week. MAIN OUTCOME MEASURES: Patients' pain and disability scores were assessed using visual analog scales and ROM was assessed using a goniometer. All parameters were measured within 24 hours after injury and after 2 and 6 months. RESULTS: After 2 months, the different periods of immobilization (2d or 10d) were associated with comparable improvements in pain symptoms (median, 4.60 vs 4.65), ROM (median, 100.0 degrees vs 117.5 degrees ), and disability score (median, 4.90 vs 5.15). No statistically significant differences could be identified between the 2 treatment groups. After 6 months, persistent pain was reported by 4 patients in each group (12.5%). CONCLUSIONS: In patients with QTF grade II whiplash injuries, there is no short- or long-term difference between 2-day and 10-day immobilization with a cervical collar in terms of pain, ROM, or disability.

Device-assisted muscle strengthening in the rehabilitation of patients after surgically stabilized vertebral fractures.

OBJECTIVES: To investigate the effects of a device-assisted muscle strengthening exercise program on the surgically traumatized multifidus musculature and on the intact longissimus and iliocostal muscles and to assess the possible relationship between patients' reported pain symptoms and changes in muscle strength or changes in cross-sectional area (CSA) of the musculature. DESIGN: Open, prospective noncontrolled prepost intervention study. SETTING: University-affiliated center for ambulant physiotherapy. PARTICIPANTS: Fifteen patients who had undergone dorsal osteosynthesis for treatment of thoracolumbar vertebral fracture and who complained of persistent back pain. INTERVENTION: Twelve-week device-assisted training exercise program. MAIN OUTCOME MEASURES: Patients' pain score, muscle strength, and the CSA of the paravertebral musculature determined by magnetic resonance imaging (MRI) were assessed before and after the exercise program. RESULTS: MRI findings revealed no increase in the CSA of the multifidus muscle in any patient (median change, -.27 cm 2 ). All patients, however, exhibited hypertrophy of both the longissimus and iliocostal muscles (median change, 1.39 cm 2 ). Significant increase in muscle strength was observed in 14 of 16 patients (median increase, 56%; range, 0.7%-126.4%). The median overall pain score improved from 19 (range, 7-24) to 16 (range, 5-27). The change in muscle strength and muscle CSA, however, showed no correlation. There was also no correlation between increase in muscle strength and changes in pain scores. CONCLUSIONS: The device-assisted training program resulted in hypertrophy of the iliocostal and longissimus muscles and an increase in muscle strength in patients with surgically stabilized vertebral fractures. About half of the patients reported relief of pain. No correlation was found between hypertrophy, increase in muscle strength, and relief of pain. The surgically damaged multifidus musculature, however, did not show any change in CSA and was not accessible to rehabilitative measures.

Surface electromyography of the paravertebral muscles in patients with chronic low back pain.

OBJECTIVE: To investigate the differences in the electromyographic signals of patients with chronic low back pain (CLBP) and healthy subjects. DESIGN: Cross-sectional study with a matched-pair design. SETTING: University hospital. PARTICIPANTS: Thirty-one patients with CLBP and 31 healthy, matched-pair controls. INTERVENTIONS: The mean rectified surface electromyographic amplitude and muscle strength were measured during maximal voluntary contraction (MVC). During an endurance test at 60% of MVC, the electromyographic parameters of the 2 groups were compared.Main outcome measure Electromyographic measuring of local fatigue, which can be described with changes in the median frequency or by a different parameter of the power spectrum called frequency banding. RESULTS: The strength measurement revealed a deficiency of 40% in the patients and a deficit in the electromyographic amplitude of approximately 60%, compared with the control group. By pairwise comparison, the decrease in the median frequency during the endurance test was greater in the control group. In the frequency banding of the power spectrum, local fatigue was less pronounced in the CLBP patients in pairwise comparison. CONCLUSIONS: The back muscles of CLBP patients appear to be less fatigable than those of controls. The results can be explained by morphologic changes, but influences such as pain, avoidance of pain, and deconditioning, need to be considered when the results are assessed.

Sonographic findings of hibernoma. A report of two cases.

We present 2 cases of hibernoma, a rare lipomatous tumor arising from brown fat tissue. In each case, a hyperechoic mass in comparison to surrounding musculature combined with elevated vascularization was highly suggestive of a liposarcoma. As a rule, malignancy cannot be excluded safely by imaging modalities, and a preoperative biopsy should be performed. Although rare, hibernomas should be considered in the differential diagnosis of lipomatous soft-tissue tumors.