High-Intensity Zones on MRI of the Cervical Spine in Patients: Epidemiology and Association With Pain and Disability.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: This study aimed to address the prevalence, distribution, and clinical significance of cervical high-intensity zones (HIZs) on magnetic resonance imaging (MRI) with respect to pain and other patient-reported outcomes in the setting of patients that will undergo an anterior cervical discectomy and fusion (ACDF) procedure. METHODS: A retrospective cohort study of ACDF patients surgically treated at a single center from 2008 to 2015. Based on preoperative MRI, HIZ subtypes were identified as either traditional T2-hyperintense, T1-hypointense ("single-HIZs"), or combined T1- and T2-hyperintense ("dual-HIZs"), and their level-specific prevalence was assessed. Preoperative symptoms, patient-reported outcomes, and disc degeneration pathology were assessed in relation to HIZs and HIZ subtypes. RESULTS: Of 861 patients, 58 demonstrated evidence of HIZs in the cervical spine (6.7%). Single-HIZs and dual-HIZs comprised 63.8% and 36.2% of the overall HIZs, respectively. HIZs found outside of the planned fusion segment reported better preoperative Neck Disability Index (NDI; P = .049) and Visual Analogue Scale (VAS) Arm (P = .014) scores relative to patients without HIZs. Furthermore, patients with single-HIZs found inside the planned fusion segment had worse VAS Neck (P = .045) and VAS Arm (P = .010) scores. In general, dual-HIZ patients showed no significant differences across all clinical outcomes. CONCLUSIONS: This is the first study to evaluate the clinical significance of HIZs in the cervical spine, noting level-specific and clinical outcome-specific variations. Single-HIZs were associated with significantly more pain when located inside the fusion segment, while dual-HIZs showed no associations with patient-reported outcomes. The presence of single-HIZs may correlate with concurrent spinal pathologies and should be more closely evaluated.

Determination of congenital absence of palmaris longus tendon with clinical examination and ultrasonography.

OBJECTIVES: The tendon of the palmaris longus is commonly used as a tendon graft in many reconstructive surgeries. Palmaris longus absence (PLA) was found in 15% among individuals worldwide. In this prospective study, we aimed to conduct an incidence study in which physical examination methods were confirmed by ultrasonography in PLA, and to evaluate the relationship of absence with age, gender, laterality and dominant hand. METHODS: The study included 490 cases. They were initially tested to evaluated by physical examination using the Schaeffer's and Hiz-Ediz test for the assessment of the palmaris longus tendon. Additional ultrasonography was performed to confirm its absence in 129 wrists of 78 cases whose tendons could not be visualized or palpated. RESULTS: The incidence of tendon absence was 13% by physical examination methods. According to the final results when we added ultrasonography to physical examination methods, the incidence of unilateral, bilateral and overall absence of the palmaris longus were 5%, 9% and 11% respectively. There was no statistically significant difference between individuals with and without PLA in terms of gender, side, age and dominant hand (p = 0.796, p = 0.622, p = 0.397 and p = 0.187, respectively). However, bilateral PLA was statistically significantly higher than unilateral in both genders (p = 0.011). CONCLUSIONS: We think that agenesis should be proven accurately by ultrasonographic examination for the final result before any surgical procedure with palmaris longus tendon. Furthermore measuring the diameter of the palmaris longus tendon by preoperative ultrasonography can be useful for surgeons who plan a procedure that requires specific measurements.

Lumbar high-intensity zones on MRI: imaging biomarkers for severe, prolonged low back pain and sciatica in a population-based cohort.

BACKGROUND CONTEXT: There is often discrepancy between clinical presentation and lumbar magnetic resonance imaging (MRI) findings. PURPOSE: The purpose of this study was to assess the relationship of high-intensity zones (HIZs) on MRI with low back pain (LBP), sciatica, and back-related disability. STUDY DESIGN: Cross-sectional, population-based Southern Chinese cohort study. PATIENT SAMPLE: Of 1,414 possible participants, data from 1,214 participants (453 males, 761 females; mean age of 48.1±6.3 years) were included. OUTCOME MEASURES: Presence of single-level, homogeneous multilevel (same type HIZs of morphology and topography) and heterogeneous multilevel (mixed type HIZs of morphology and topography) HIZs and other MRI phenotypes were assessed at each level with T2-weighted 3T sagittal MRI of L1-S1. Associations with LBP, sciatica and Oswestry Disability Index were correlated with HIZ profiles. RESULTS: In all, 718 individuals had HIZs (59.1%). Disc degeneration/displacement were more prevalent in HIZ individuals (p<.001). HIZ subjects experienced prolonged severe LBP more frequently (39.6% vs. 32.5%; p<.05) and had higher Oswestry Disability Index scores (10.7±13.7 vs. 8.9±11.3; p<.05). Posterior multilevel HIZ were significantly associated with prolonged severe LBP (OR: 2.18; 95% CI:1.42-3.37; p<.05) in comparison to anterior only, anterior/posterior or other patterns of HIZ. Multilevel homogeneous or heterogeneous HIZs were significantly associated with prolonged, severe LBP (OR: 1.53-1.57; p<.05). Individuals with homogeneous HIZs had a higher risk of sciatica (OR: 1.51, 95% CI: 1.01-2.27; p<.05). CONCLUSIONS: This is the first large-scale study to note that lumbar HIZs, and specific patterns therein, are potentially clinically-relevant imaging biomarkers that are independently and significantly associated with prolonged/severe LBP and sciatica. HIZs, especially homogenous multilevel HIZ, should be noted in the global pain imaging phenotype assessment.

Passage survival of European and American eels at Francis and propeller turbines.

We present the magnitude of losses of European eel Anguilla anguilla and American eel A. rostrata in passage through propeller and Francis turbines at hydroelectric projects. Survival and injury rates and types were turbine type related. Overall, eel survival was higher (mean ± 90% CI = 95.1 ± 5.3%,) and injury rate lower (12.5 ± 10.5) at Francis than propeller turbines (survival = 80.7 ± 6.4%; injury rate = 25.7 ± 7.9%). The common injury type at Francis turbines was bruises and at propeller turbines was severance. Blade shape and thickness of the leading edge of the blades (rounded, thick buckets of Francis turbines v. flatter, sharper edged blades in propeller turbines); eel entry routes into the turbines; their flexible, cylindrical body shape and orientation probably contributed to these differences. Relationship between survival and injury and turbine characteristics was turbine specific. For Francis turbines, one negative correlation (r = -0.986, P < 0.01) between survival and runner speed was found and two positive correlations between injury rates and fish length (r = 0.740, P < 0.10) and number of blades (r = 0.835, P < 0.05) were noted for propeller turbines. Several severely injured eels remained active 48 h after turbine passage suggesting caution is warranted when using telemetric movement for estimating eel survival. We conclude there is a need to (a) better understand travel paths and approach orientation of eels through turbines; (b) determine where only eel passage is of concern at hydropower plants that have both turbine types and therefore preferential operation of Francis turbines may be considered; (c) inform hydropower plant operators where turbine replacement is being considered and downstream eel passage is of concern that replacement by Francis or bulb turbines may prove beneficial for eel passage.

The relevance of high-intensity zones in degenerative disc disease.

PURPOSE: The purpose of this study was to review the current understanding of high-intensity zones (HIZ) in the lumbar spine with particular attention to its imaging phenotype and clinical relevance. METHODS: A review was conducted of studies related to HIZ. Particular attention was made to imaging phenotypes and classification, and its relationship with discogenic low back pain (LBP). RESULTS: The most current classification system of HIZ is based on location (anterior and posterior), morphology (round, fissure, vertical, rim, or giant types), and its appearance on both T1- and T2-weighted magnetic resonance imaging (MRI). HIZ are commonly manifested with disc degeneration. Hence, both conditions share similar risk factors such as the effect of frequent and prolonged disc loading. The clinical significance of HIZ however is not conclusive. Provocative discography is not sensitive (~ 70%) for eliciting a concordant pain response. Population-based studies have conflicting results regarding the prevalence (14-63%) of HIZ and its correlation with LBP. CONCLUSIONS: HIZ are likely a risk factor for discogenic LBP. However, its etiology and pathophysiology are not well understood. Some clinical studies suggest a link between its occurrence and LBP. However, the results are not consistent as a result of studies which are underpowered and based on heterogeneous study populations, lacking control groups, and without standardized imaging phenotypes. HIZ may be an important pain biomarker that should be further studied. With more modern MRI technology and a detailed classification system, future large-scale population studies will improve our knowledge on its role in the disc degeneration cascade and development of LBP.

The association of high-intensity zones on MRI and low back pain: a systematic review.

BACKGROUND: Magnetic resonance imaging (MRI) of the lumbar spine is commonly used to identify the source of low back pain (LBP); however, its use has been questionable. Throughout the years, numerous lumbar phenotypes (e.g., endplate abnormalities, Modic changes, black disc) have been studied as possible pain generators. High-intensity zones (HIZs) are of particular interest as they may represent annular tears. However, for over three decades, there has been heated debate as to whether these imaging biomarkers are synonymous with LBP. Therefore, the following study addressed a systematic review of the reported literature addressing the relationship of HIZs and LBP. METHODS: A systematic review was conducted via MEDLINE, SCOPUS, Cochrane, PubMed, PubMed Central, EMBASE via Ovid, and Web of Science with the following search terms: "HIZ," "high intensity zone," or "high intensity zones" and "low back pain," "pain," "lumbago," and/or "sciatica." Specific exclusion criteria were also maintained. Two independent reviewers searched the literature, selected the studies, and extracted the data. RESULTS: We identified six studies from our search strategy that met the inclusion criteria from a total of 756 possible studies. One cross-sectional population-based study and five comparison studies were identified, which provided information regarding the prevalence of HIZs. The prevalence of HIZs was 3 to 61% in subjects with LBP and 2 to 3% in subjects without LBP. Only three studies suggested a significant association between the presence of HIZ and LBP with or without sciatica. CONCLUSIONS: Our systematic review has found evidence that HIZs may be a possible risk factor for LBP; however, a mismatch of the clinical relevance of HIZs between studies still remains. The available evidence is limited by small sample size, heterogeneous study populations, and lack of standardized imaging methods for phenotyping. HIZs may be important lumbar biomarkers that demand further investigation and should be considered in the global imaging assessment of the spine, which may have immense clinical utility. Further large-scale studies with standardized imaging and classification techniques as well as the assessment of patterns of HIZs are necessary to better understand their role with LBP development.

The value of radiographic indexes in the diagnosis of discogenic low back pain: a retrospective analysis of imaging results.

To explore value of different radiographic indexes in the diagnosis of discogenic low back pain (LBP). A total number of 120 cases (60 patients diagnosed with discogenic LBP and 60 healthy people) were retrospectively analysed to identify factors in the diagnosis of discogenic LBP by using univariate and multivariate analyses. A receiver operating characteristic (ROC) curve was drew to show the predictive accuracy of the finally enrolled factors. Among all the included patients, 60 were strictly admitted in the discogenic LBP group while the other 60 were enrolled in the control group. Five results shows significant differences between discogenic LBP and control groups, including Cobb angle, lumbar stability, height of the disc, Modic change and High intense zone (HIZ) based on the results of univariate analysis; lumbar stability, Modic change and HIZ show high value in the diagnosis of lumbar discogenic pain based on the multivariate logistic analysis. The ROC curve shows that good diagnostic accuracy was obtained from the enrolled diagnostic factors including lumbar stability (Angular motion, more than 14.35°), Modic change and HIZ.

Do presence and location of annular tear influence clinical outcome after lumbar total disc arthroplasty? A prospective 1-year follow-up study.

BACKGROUND: Lumbar total disc arthroplasty is often performed in patients with axial back pain. There are multiple etiologies for axial back pain, including disc degeneration and annular tears. The location of these annular tears can vary, producing differing preoperative symptomatology. Intraoperatively, disruptions in the annulus are identifiable, and it has been suggested that patients with discrete annular tears may have better clinical outcomes after surgery. The purpose of this study was to investigate whether the presence and location of annular tears have an effect on clinical outcomes after lumbar total disc arthroplasty. METHODS: Patients undergoing a single-level anterior disc replacement from L3-S1 at a single site by a single surgeon were evaluated preoperatively for the presence or absence of annular tears with magnetic resonance imaging. All patients were part of either the ProDisc (n = 41) (Synthes, Paoli, Pennsylvania) or Activ-L (n = 19) (Aesculap [B. Braun Melsungen AG], Tuttlingen, Germany) lumbar prospective clinical trials. In those patients with annular tears, the location of the tear (central, paracentral, or lateral) was documented. Patients were assessed at 6 and 12 months after lumbar total disc arthroplasty with the Oswestry Disability Index (ODI), visual analog scale (VAS) score for back pain, VAS score for leg pain, and radiographic imaging. All radiographic evaluations were conducted by an attending neuroradiologist and an attending spinal surgeon, and reliability testing was performed. An analysis of variance was performed among the 3 anatomic locations of annular tears. RESULTS: A total of 60 patients were included and had complete 12-month follow-up. The prevalence of annular tears among all patients was 42% (n = 25). Outcome data in patients without annular tears were as follows: ODI, 66% preoperatively and 26% postoperatively; VAS score for back pain, 8.0 preoperatively and 2.6 postoperatively; and VAS score for leg pain, 2.9 preoperatively and 1.2 postoperatively. Among those patients with tears, the prevalence of central tears was 80%, the prevalence of paracentral tears was 12%, and the prevalence of lateral tears was 8%. Outcome data in patients with central tears were as follows: ODI, 66% preoperatively and 26% postoperatively; VAS score for back pain, 7.8 preoperatively and 2.6 postoperatively; and VAS score for leg pain, 5.2 preoperatively and 0.5 postoperatively. Outcome data in patients with paracentral tears were as follows: ODI, 86% preoperatively and 59% postoperatively; VAS score for back pain, 8.8 preoperatively and 3.3 postoperatively; and VAS score for leg pain, 5.0 preoperatively and 5.4 postoperatively. Outcome data in patients with lateral tears were as follows: ODI, 6.5 preoperatively and 2.6 postoperatively; VAS score for back pain, 9.2 preoperatively and 0.2 postoperatively; and VAS score for leg pain, 1.4 preoperatively and 0.7 postoperatively. In those patients with paracentral tears, there was a significantly higher incidence of postoperative radicular symptoms both from an intensity standpoint and from a duration standpoint. Other complications did not vary among those patients with or without annular tears. CONCLUSIONS: Although patients with annular tears and patients without annular tears improve after lumbar artificial disc replacement, those with central annular tears or without tears have significantly lower disability scores than those with paracentral tears or lateral tears, whose outcome scores showed significantly less improvement (P ≤ .03). In particular, patients with central tears have less postoperative leg pain than those with paracentral annular tears. In this study the presence or absence of an annular tear on magnetic resonance imaging was not a significant predictive factor for clinical outcome. Further investigation regarding the effects of paracentral annular tears and surgical techniques should be explored.