Generative adversarial networks for spine imaging: A critical review of current applications.

PURPOSE: In recent years, the field of medical imaging has witnessed remarkable advancements, with innovative technologies which revolutionized the visualization and analysis of the human spine. Among the groundbreaking developments in medical imaging, Generative Adversarial Networks (GANs) have emerged as a transformative tool, offering unprecedented possibilities in enhancing spinal imaging techniques and diagnostic outcomes. This review paper aims to provide a comprehensive overview of the use of GANs in spinal imaging, and to emphasize their potential to improve the diagnosis and treatment of spine-related disorders. A specific review focusing on Generative Adversarial Networks (GANs) in the context of medical spine imaging is needed to provide a comprehensive and specialized analysis of the unique challenges, applications, and advancements within this specific domain, which might not be fully addressed in broader reviews covering GANs in general medical imaging. Such a review can offer insights into the tailored solutions and innovations that GANs bring to the field of spinal medical imaging. METHODS: An extensive literature search from 2017 until July 2023, was conducted using the most important search engines and identified studies that used GANs in spinal imaging. RESULTS: The implementations include generating fat suppressed T2-weighted (fsT2W) images from T1 and T2-weighted sequences, to reduce scan time. The generated images had a significantly better image quality than true fsT2W images and could improve diagnostic accuracy for certain pathologies. GANs were also utilized in generating virtual thin-slice images of intervertebral spaces, creating digital twins of human vertebrae, and predicting fracture response. Lastly, they could be applied to convert CT to MRI images, with the potential to generate near-MR images from CT without MRI. CONCLUSIONS: GANs have promising applications in personalized medicine, image augmentation, and improved diagnostic accuracy. However, limitations such as small databases and misalignment in CT-MRI pairs, must be considered.

Imaging of Anatomical Variants Around the Hip.

Considering the current widespread use of imaging as an integral part of managing hip pain, variable hip geometries and anatomical variants are increasingly being detected. These variants are commonly found in the acetabulum and proximal femur, as well as the surrounding capsule-labral tissues. The morphology of specific anatomical spaces confined by the proximal femur and the bony pelvis may also vary significantly among individuals. Familiarity with the spectrum of imaging appearances of the hip is necessary to identify variant hip morphologies with or without potential clinical relevance and reduce an unnecessary work-up and overdiagnosis. We describe anatomical variations and variable morphologies of the bony structures comprising the hip joint and the soft tissues, around the hip. The potential clinical significance of these findings is further analyzed in conjunction with the patient's profile.

The Impact of Distance Learning and COVID-19 Lockdown on Students' Physical Activity and Musculoskeletal Health.

PURPOSE: During the past two years, in most institutions worldwide, educational activities were remodeled for remote delivery, due to the COVID-19 pandemic. The purpose of this study is to assess the effects of two-year distance learning on the physical activity and musculoskeletal health of university students. METHODS: This was a national, cross-sectional study using data collected via an online questionnaire distributed through university communication platforms, which included questions on online education routines, musculoskeletal health, and physical activity of university students. RESULTS: In total, 1,366 students (65% female, 35% male) from 11 universities took part in the survey. The most common sites of reported pain were the neck (59.5%), shoulders (22.8%), back (29%), and low back (66.7%). Musculoskeletal pain significantly increased during the lockdown, according to the visual analog scale (VAS) for pain (before: 2.7 ± 1.6; during: 5.5 ± 2.2, p<0.001). Everyday pain was referred by significantly more students during the lockdown (4.5% vs 36.1 %, p<0.001), while the percentage of asymptomatic students was significantly decreased (40.5% vs 6.1%, p<0.001). Concerning physical activity, the percentage of students who did not exercise significantly increased during the lockdown (15.1% vs 23.2%, p<0.001). Distance learning and total screen time were positively correlated with VAS for pain scores. On the contrary, an increased frequency of ergonomic position, walking intervals, and physical activity was associated with significantly decreased VAS for pain scores. CONCLUSIONS: Distance learning and limited physical activity led to a significant increase in musculoskeletal pain in university students, while exercise and ergonomic body position were considered protective factors. Interventions to encourage physical activity and healthy studying habits should be developed by universities, since distance learning may be again necessary for the future.

Deep Learning for the Differential Diagnosis between Transient Osteoporosis and Avascular Necrosis of the Hip.

Differential diagnosis between avascular necrosis (AVN) and transient osteoporosis of the hip (TOH) can be complicated even for experienced MSK radiologists. Our study attempted to use MR images in order to develop a deep learning methodology with the use of transfer learning and a convolutional neural network (CNN) ensemble, for the accurate differentiation between the two diseases. An augmented dataset of 210 hips with TOH and 210 hips with AVN was used to finetune three ImageNet-trained CNNs (VGG-16, InceptionResNetV2, and InceptionV3). An ensemble decision was reached in a hard-voting manner by selecting the outcome voted by at least two of the CNNs. Inception-ResNet-V2 achieved the highest AUC (97.62%) similar to the model ensemble, followed by InceptionV3 (AUC of 96.82%) and VGG-16 (AUC 96.03%). Precision for the diagnosis of AVN and recall for the detection of TOH were higher in the model ensemble compared to Inception-ResNet-V2. Ensemble performance was significantly higher than that of an MSK radiologist and a fellow (P < 0.001). Deep learning was highly successful in distinguishing TOH from AVN, with a potential to aid treatment decisions and lead to the avoidance of unnecessary surgery.

A Review of the Outcomes of the Implementation of Case-Based Anatomy Learning.

PURPOSE: Clinically-oriented anatomy education has been proposed as an effective strategy in anatomy curricula. We aimed to explore the level of extent the literature supports the fact that case-based learning (CBL) can play a significant role in anatomy education. MATERIALS AND METHODS: We searched PubMed, Scopus, Education Resources Information Center (ERIC), and Cochrane database to find articles with the purpose to explore the educational outcomes of case-based anatomy learning. We extracted from each paper authors, type of study (comparative or not), number of participants, level of outcome according to the Kirkpatrick hierarchy, outcomes of CBL concerning the acquisition of anatomical knowledge, and the participants' perceived enjoyment, motivation, and aid to anatomy learning. RESULTS: Nine articles were included. Three of them evaluated the acquisition of anatomical knowledge, while six papers evaluated the participants' perceptions. All studies showed positive outcomes regarding the students' anatomy examination performances, reported confidence, enjoyment, motivation, and ability of CBL to facilitate anatomy learning. CONCLUSION: Although the existing research has mainly evaluated students' perceptions, the outcomes of CBL in anatomy education encourage more extensive use of this method in anatomy curricula. Further research is expected to shed more light on the role that CBL can play in modern anatomy education and to clarify if it can replace or supplement didactic teaching.

Knee Capsule Anatomy: An MR Imaging and Cadaveric Study.

This research focuses on the anatomical insertion of the synovial capsule around the knee. The attachments of the capsule were measured in 50 knee MR imaging studies with large intraarticular effusion. Corresponding measurements were performed in 20 fresh frozen cadaveric specimens, for validation. Femoral and tibial capsular reflections were defined as the distances between the attachment sites of the capsule and the femoral or tibial joint line and they were recorded in three coronal planes (anterior/middle/posterior). On MR imaging, the lateral/medial femoral capsular reflection mean values were 6.5/4.57 cm, 2.74/1.74 cm and 1.52/1.99 cm in the anterior, middle and posterior plane, respectively. MR imaging-based measurements did not differ significantly compared to corresponding cadaveric measurements. The mean values of the lateral/medial tibial capsular reflection on MR imaging were 0.09/0.11 cm, 0.34/0.26 cm and 0.62/0.34 cm in the anterior, middle and posterior plane, respectively. On cadaveric dissection, the maximum mean value was 1.45 cm, measured on the lateral side of the anterior plane. Apart from the lateral aspect of the posterior plane, MR imaging measurements were significantly lower, compared to the corresponding cadaveric measurements. The greatest femoral and tibial capsular reflections were found on the anterior and lateral side of the anterior plane. MR imaging appears to underestimate the distal extent of the knee capsule. Anatomical details of the knee capsule should be considered for safe insertion of external fixator pins.

Clinical and Radiological Outcomes After Isolated Anterior Horn Repair of Medial and Lateral Meniscus at 24 Months' Follow-up, With the Outside-In Technique.

Background The effects of repair of isolated anterior horn meniscus lesions have not been thoroughly described in the literature. We aimed to evaluate outcomes with subjective clinical scores and imaging modalities after repair of isolated anterior horn tears, at 24 months' follow-up. Methods Records of all patients that opted for surgical repair of isolated, anterior horn tears of the medial and lateral meniscus were retrospectively reviewed, between 2016 and 2018. All patients were treated with arthroscopic outside-in technique by the same surgeon. Preoperative and postoperative clinical files were accessed to recover records of preoperative symptomatology, patient-reported scores [International Knee Documentation Committee (IKDC) rating, Lysholm score and Tegner activity level], preoperative and postoperative MRI data and time from injury to surgery. Results Mean age of eight patients was 25.25 years (range 18-37 years). Diagnostic preoperative MRI revealed isolated anterior horn tear of the lateral meniscus and medial meniscus in five patients and an isolated anterior horn tear of the medial meniscus in three patients. Mean time from injury to surgical repair was 23.75 days (range 7-43). We considered seven out of eight repairs to be successfully healed. At 24 months' follow-up: Mean Lysholm score was 92.25 (range 89-95), Tegner activity scale score was 6.5 (range 5-8) and IKDC score was 91.78 (range 87.8-94.4). All scores significantly improved compared to preoperative values (p<0.001). Conclusions Outside-in is a reliable technique to repair meniscal anterior horn tears, both medially and laterally, with high healing rates and patient satisfaction in young, active patients.

Radiomics and Machine Learning Can Differentiate Transient Osteoporosis from Avascular Necrosis of the Hip.

Differentiation between transient osteoporosis (TOH) and avascular necrosis (AVN) of the hip is a longstanding challenge in musculoskeletal radiology. The purpose of this study was to utilize MRI-based radiomics and machine learning (ML) for accurate differentiation between the two entities. A total of 109 hips with TOH and 104 hips with AVN were retrospectively included. Femoral heads and necks with segmented radiomics features were extracted. Three ML classifiers (XGboost, CatBoost and SVM) using 38 relevant radiomics features were trained on 70% and validated on 30% of the dataset. ML performance was compared to two musculoskeletal radiologists, a general radiologist and two radiology residents. XGboost achieved the best performance with an area under the curve (AUC) of 93.7% (95% CI from 87.7 to 99.8%) among ML models. MSK radiologists achieved an AUC of 90.6% (95% CI from 86.7% to 94.5%) and 88.3% (95% CI from 84% to 92.7%), respectively, similar to residents. The general radiologist achieved an AUC of 84.5% (95% CI from 80% to 89%), significantly lower than of XGboost (p = 0.017). In conclusion, radiomics-based ML achieved a performance similar to MSK radiologists and significantly higher compared to general radiologists in differentiating between TOH and AVN.

A Single-Center Surgical Experience With the Reverse Sural Artery Flap as a Reliable Solution for Lower Leg Soft Tissue Defects, With Minimum Two-Year Follow-Up.

AIM: Small soft tissue defects of the distal tibia and hindfoot resulting from traumatic, operative, or neoplastic conditions and chronic ulcers can be successfully dealt with the use of the reverse sural artery flap (RSAF). This study aims to describe a single center's results and familiarity with this technique over a 15-year period of time. MATERIAL AND METHODS: We retrospectively reviewed the clinical files of patients who were consecutively treated with RSAF and regularly followed up between January 1, 2004 and December 31, 2018, with a minimum postoperative follow-up period of two years. Patient demographics and comorbidities, location of the defect, performing surgeon, mean operation time, flap pedicle width, mean size of the defect, days of hospitalization following the operation, healing flap rate, and complications were recorded. RESULTS: The sample consisted of 30 adult patients (25 men, 5 women), with a mean age of 51.07 years (16-80 years, SD 18.61). The mean operation time was 99.03 min (range 83-131, SD 10.57), and the mean size of the defect was 11.11 cm2 (range 6.1-19.4, SD 3.22). Successful flap rate (complete healing and coverage of the defect, with or without additional minor intervention) was 83.3% (25/30). Among successfully healed flaps, six patients with partial necrosis of the dermis were treated by an additional split-thickness skin graft. Five flaps failed to heal. Deep infection was present in two patients, leading to flap failure and reoperation. Serious venous congestion resulting in flap ischemia occurred in three cases. Circumferential keloid formation (not affecting successful outcome) was present in seven cases. Flap thickness approximated to normal within six months. All donor sites healed well (either by a split-thickness cutaneous flap or by immediate wound closure). Light paresthesia on the lateral border of the leg and foot disappeared within six months. CONCLUSIONS: A single-center experience with the RSAF has yielded satisfactory clinical outcomes, and the long-term tackle with the difficult reconstruction conditions around the ankle, has led to valuable advice on surgical technique and postoperative protocol, based on an anatomical basis.

A New Alternative Surgical Treatment of Hallux Valgus, in Moderate to Severe Cases of the Disease With a Two-and-a-Half-Year Follow-Up.

The study aims to evaluate the treatment of moderate to severe forms of hallux valgus with the lowest invasiveness in soft tissues and especially with an alternative modified Chevron osteotomy of the first metatarsal. Additionally, it emphasizes the necessity of the modified McBride procedure (capsuloplasty and release of specific concrete soft tissue structures) and the importance of the soft tissue manipulation in the particular surgery intra-operatively, as well as postoperative medical and personal care and duration of rehabilitation. Patients with an average age 58 years (range 51-65), who underwent a Chevron type osteotomy with combination of soft tissues interventions laterally and medially of the first metatarsophalangeal joint, for symptoms they had of systematic hallux valgus without any other degenerative problems in metatarsophalangeal joint between 2017 to the beginning of 2018, were retrospectively reviewed with an average follow-up of 29 months (range 26-31).

The effect of injection volume on long-term outcomes of US-guided subacromial bursa injections.

PURPOSE: Limited data exist on the efficacy of high- compared to low-volume US-guided corticosteroid injections (CI) in the subacromial-subdeltoid (SA-SD) bursa. Our purpose was to compare the short- and long-term efficacy of low- and high-volume injections, by using a capacity reference of SA-SD bursa volume, as assessed on cadaveric specimens. METHOD: Within two years, 136 patients (63 males, 73 females; mean age: 46.11 ±â€¯10.28 years) who underwent SA-SD bursa US-guided CI for subacromial impingement, rotator cuff tendinopathy or shoulder overuse were prospectively included. Patients were randomly assigned to low-volume (1 mL triamcinolone acetonide/40 mg) or high-volume (1 mL triamcinolone acetonide/40 mg, 9 mL anaesthetic agents) groups (67 and 69 patients, respectively). Visual Analogue Scores (VAS) were recorded at baseline, 30 min, 3 weeks, 3 months, 6 months and 1 year post-treatment. Predictors of complete recovery (VAS ≤ 2) at 1 year were analysed with multivariate Cox regression analysis. SA-SD bursa cadaveric dissection in 10 specimens was performed for volume assessment. RESULTS: Injection volume was the only predictor of complete pain resolution at 1 year. High-volume CI yielded higher chances of early pain recovery (2.837 HR, 95% CI 1.737-4.633, P < .001). Mean VAS scores at baseline and subsequent time-points were 6, 2.6, 2.2, 2, 1.6 and 1 for the high-volume and 7.8, 7.3, 4.7, 3.2, 2.5 and 1.8 for the low-volume group, respectively (P < .001, at all time-points). Cadaveric measurements showed a minimum SA-SD bursa volume of approximately 6.9 mL. CONCLUSIONS: High-compared to low-volume US-guided CI are superior for achieving early pain recovery.

A Transverse Carpal Muscle Causing Carpal Tunnel Syndrome.

Accessory and atypical muscles of the upper limb are common, whereas symptomatic variations presenting with carpal tunnel syndrome (CTS) are rare. A rare unilateral accessory transverse carpal muscle located palmar to the transverse carpal ligament is described. The accessory muscle, associated with CTS clinical manifestations in a 38-year-old Greek male worker, can be quite problematic during CTS operation. The current case emphasizes the importance of meticulous knowledge of the variable anatomy of the carpal tunnel (CT) area, since the accessory muscles may be accompanied by ectopic motor branches and a high risk of iatrogenic injury. Recognition and careful evaluation of accessory muscles may enhance a surgeon's ability to carry out a safer and successful CT approach.

Anatomy Learning from Prosected Cadaveric Specimens Versus Plastic Models: A Comparative Study of Upper Limb Anatomy.

Human cadaveric prosections are a traditional, effective, and highly appreciated modality of anatomy learning. Plastic models are an alternative teaching modality, though few studies examine their effectiveness in learning of upper limb musculoskeletal anatomy. The purpose of this study is to investigate which modality is associated with a better outcome, as assessed by students' performance on examinations. Overall, 60 undergraduate medical students without previous knowledge of anatomy participated in the study. Students were assigned into two groups. Group 1 attended lectures and studied from cadaveric prosections (n = 30) and Group 2 attended lectures and used plastic models in the laboratory (n = 30). A knowledge assessment, including examination with tag questions (spot test) and written multiple-choice questions, was held after the end of the study. Students' perceptions were also investigated via an anonymous questionnaire. No significant difference in students' performance was observed between the group using prosections and the group using plastic models (32.2 ± 14.7 vs 35.0 ± 14.8, respectively; P = 0.477). Similarly, no statistically significant difference was found regarding students' satisfaction from using each learning modality (P = 0.441). Plastic models may be a valuable supplementary modality in learning upper limb musculoskeletal anatomy, despite their limitations. Easy to use and with no need for maintaining facilities, they are highly appreciated by students and can be useful when preparing for the use of cadaveric specimens.

An Uncommon Case of Atraumatic Palsy of a Branch of the Anterior Interosseous Nerve with a Late Spontaneous Recovery.

Atraumatic palsy of the anterior interosseous nerve (AIN) is rarely encountered, presenting an uncertain etiology which provokes a weakness of the flexor pollicis longus (FPL), flexor digitorum profundus (FDP), and pronator quadratus, while a lesion of one of the AIN branches is even rarer. In many cases, the diagnosis is based in motor deviations due to nerve's palsy. A palsy of the AIN can be "complete" or "incomplete." In an incomplete palsy, only the FPL or the FDP of the index finger is paretic or paralyzed. There is a scientific debate concerning the effectiveness between surgical and conservative treatment approaches. Moreover, a patient may have the opportunity to decide whether to be submitted in an interventional procedure or not. The purpose of this paper is to report a case of an AIN's branch palsy and to suggest a possible delay of the surgical exploration, since a late self-recovery may occur.

Magnetic resonance morphometry of the adult normal lumbar intervertebral space.

PURPOSE: This study aims to: (a) quantify and evaluate normal relationships between neighboring spinal units using MR imaging indices, (b) propose an easy-to-apply-and-reproduce method of estimating the correct amount of distraction when surgically restoring a collapsed intervertebral disc, based on individualized measurements. METHODS: This is a retrospective cross-sectional MR imaging study of 119 adult subjects, aged 18-54, asymptomatic for low back pain. Each of the examinees should demonstrate two or more consecutive intervertebral discs classified as Pfirrmann grade I or II to be included. We measured and studied the relationships of disc height index, Dabbs index, Farfan index, disc convexity index and mean and posterior disc height per spinal level using multiple regression analysis. All measurements were tested for intra- and interobserver agreement by two raters. RESULTS: DHI, Dabbs, Farfan, and mean disc height had a statistically significant correlation with the spinal level and age. Our results were highly reproducible, with excellent inter- and intraobserver agreement and reliability between two raters (ICC = 0.992 and 0.994, respectively). Furthermore, we expressed each intervertebral space as a percentage of its adjacent space, introducing the coefficient α factor for every intervertebral space. CONCLUSIONS: Our results suggest that a normal values' database to refer during preoperative planning of correction of a degenerated intervertebral disc is feasible. Our study offers new anatomical and radiological insight in terms of spinal measurements and their potential correlation with current surgical techniques. A new approach for calculating disc space as an expression of its adjacent disc has been introduced with various potential applications.

Anatomy learning from prosected cadaveric specimens versus three-dimensional software: A comparative study of upper limb anatomy.

INTRODUCTION: Modern, three-dimensional (3D) anatomy software is a promising teaching method, though few studies examine its effectiveness on upper limb and musculoskeletal anatomy learning. The purpose of this study is to investigate which method is associated with a better outcome, as assessed by students' performance on examinations, when comparing learning with prosections to the use of 3D software. MATERIALS AND METHODS: Two groups of undergraduate, first-year medical students without previous knowledge of anatomy were compared. Overall, 72 students attended lectures and cadaveric prosections in the laboratory (n=40), or lectures and the BioDigital Human software (n=32). Four hours of lectures and four hours of laboratory work, combining brief demonstration and independent study in small teams, were completed by each group. An anonymous examination, including tag questions from both cadaveric and 3D images, and multiple-choice questions, was held after the end of the educational process. Students' perceptions were also investigated via an anonymous questionnaire, which comprised 15 questions. Chi-square and student's t-test were used for comparisons. RESULTS: Students using the 3D software showed better performance in examinations, compared to students using prosection (mean: 55.88±19.60 vs. 48±16.11; p=0.05, Cohen's d=0.5). No statistically significant difference was found regarding students' satisfaction from using each learning method (p=0.39). CONCLUSIONS: Although prosection is the most common method of teaching anatomy, recent technologies, such as 3D software, are also considered useful teaching tools. However, further research has to be done before they can be safely used as a part of a multimodal curriculum, since results from this study are limited to the upper limb musculoskeletal anatomy.

Morel-Lavallée Lesions of the Knee: MRI Findings Compared With Cadaveric Study Findings.

OBJECTIVE: The purpose of this study is to describe the MRI findings and treatment decisions and outcome for Morel-Lavallée lesions (MLLs) of the knee and to investigate whether evidence exists to support an increased frequency of such lesions on the medial or lateral side by performing a cadaveric experiment. MATERIALS AND METHODS: In a 4-year period, 24 MRI studies of 24 consecutive patients (16 male patients and eight female patients) with knee MLLs were retrospectively reviewed. Patient demographic characteristics, treatment decisions and outcome, and associated injuries were recorded. The location of the MLL was categorized as medial, lateral, or global. Lesions were categorized according to an established MRI classification. During the cadaveric experiment, the compartmental pressures of the medial or lateral aspect of the knee were monitored in 20 cadaveric knees. The chi-square test, t test, and Pearson correlation were used for statistical analysis. RESULTS: MLLs were located medially in 16 patients, laterally in two patients, and globally in six patients. The medial location was significantly more common than a lateral or global location (p < 0.05). MLLs were classified as type I in 14 patients, type II in eight patients, and type III in two patients. MRI type was correlated with the chronicity of injury (r2 = 0.614; p = 0.0014). Fractures were the most common associated injuries, occurring in seven of 24 patients. In 17 patients, all of whom had conservatively treated type I or type II lesions, complete resolution of the MLL occurred. The maximum compartmental pressures were significantly higher on the lateral side than on the medial side (p < 0.0001). CONCLUSION: Knee MLLs have a predilection for the medial side, which may be attributed to the lower resistance in this location, and they have variable patterns on MRI, which correlate with chronicity. Conservative treatment of type I and II lesions seems effective.

Great trochanter bursitis vs sciatica, a diagnostic-anatomic trap: differential diagnosis and brief review of the literature.

PURPOSE: The purpose of this study is to point out the difficulty of differentiating great trochanter bursitis (GTB) from sciatica and estimating the prevalence of GTΒ, in patients poorly diagnosed with sciatica in their first visit to the general practitioner and referred to a spine infirmary. METHODS: The diagnosis of GTΒ was made based on history and physical examination, and was confirmed by ultrasonography and/or response to an anesthetic plus corticosteroid injection to the trochanteric bursa. Demographic and clinical characteristics of the study group were evaluated. The statistical analysis was held with the SPSS pc package (version 24.0). RESULTS: In a total of 657 referrals for sciatica, 72 patients (10.95%) were incorrectly diagnosed as suffering from sciatica, whereas, in fact, they were suffering from GTΒ. In addition, 18 patients (2.74%) were diagnosed as suffering from persistent sciatica with coexisting GTΒ. More women than men had GTΒ (79-11). Mean age for patients with sciatica diagnosis but suffering from GTΒ was 60 years. Mean age for patients with both sciatica and GTΒ was 61 years. CONCLUSIONS: The GTB is a common clinical entity in middle-aged women, which can escape from the physician in cases of incomplete medical history and clinical examination, leading to unnecessary imaging tests and treatment approaches, burdening both the patient and the health system. Early diagnosis of GTB may dramatically reduce cost, prevent unwanted and inappropriate imaging exams and treatment, and make the patient free of symptoms immediately. These slides can be retrieved under Electronic Supplementary Material.

Detection of O-Linked-N-Acetylglucosamine Modification and Its Associated Enzymes in Human Degenerated Intervertebral Discs.

STUDY DESIGN: Human herniated discs were obtained from discectomy specimens for the immunohistochemical detection of O-GlcNAc and O-GlcNAcase (OGA)/O-GlcNAc transferase (OGT). PURPOSE: This study aimed to quantify the extent of O-GlcNAcylation and its associated enzymes (OGT/OGA) in human degenerated intervertebral discs. OVERVIEW OF LITERATURE: The O-GlcNAcylation of nuclear, cytoplasmic, and mitochondrial proteins as well as the effects of such post-translational modifications are currently the focus of extensive research. O-GlcNAcylation is believed to contribute to the etiology of chronic illnesses by acting as a nutrient and stress sensor in the cellular environment. Mature intervertebral disc cells are chondrocyte-like cells, and O-GlcNAc has been shown to promote chondrocyte apoptosis in vitro. We believe that O-GlcNAcylation is a key regulator of disc degeneration. METHODS: Fifty-six specimens were fixed for 24 hours in a 10% solution of neutral-buffered formaldehyde, dehydrated, and embedded in paraffin. Tissue slices (4-µm-thick) were used for hematoxylin-eosin staining and immunohistochemistry. RESULTS: We found that O-GlcNAcylation of cytoplasmic proteins was less than that of nuclear proteins in both single cells and cell clusters. Cytoplasmic O-GlcNAcylation occurs subsequent to nuclear O-GlcNAcylation and is directly proportional to disc degeneration. OGT and O-GlcNAc expression levels were identical in all specimens examined. CONCLUSIONS: O-GlcNAc and OGA/OGT expression is shown to correlate for the first time with intervertebral disc cell degeneration. Increasing disc degeneration is associated with increasing O-GlcNAcylation in both nuclear and cytoplasmic proteins in human disc cells.

Imaging of impingement syndromes around the hip joint.

Impingement syndromes are increasingly recognised as significant causes of hip pain and dysfunction. A broad spectrum of intraarticular and extraarticular conditions has been implicated in their pathophysiology. Physical examination is often inconclusive as clinical findings may be unclear or misleading, often simulating other disorders. With current improvements in imaging techniques and better understanding of hip impingement related pathomechanisms, these entities can be accurately diagnosed. In addition, preoperative imaging has allowed for targeted treatment planning. This article provides an overview of the various types of hip impingement, including femoroacetabular impingement, ischiofemoral impingement, snapping hip syndrome, greater trochanteric-pelvic and subspine impingement. Current literature data regarding their pathogenesis, clinical manifestation and imaging work-up are discussed.