Canal Size Research Articles

Precise levels of the Drosophila adaptor protein Dreadlocks maintain the size and stability of germline ring canals.

ABSTRACTIntercellular bridges are essential for fertility in many organisms. The developing fruit fly egg has become the premier model system to study intercellular bridges. During oogenesis, the oocyte is connected to supporting nurse cells by relatively large intercellular bridges, or ring canals. Once formed, the ring canals undergo a 20-fold increase in diameter to support the movement of materials from the nurse cells to the oocyte. Here, we demonstrate a novel role for the conserved SH2/SH3 adaptor protein Dreadlocks (Dock) in regulating ring canal size and structural stability in the germline. Dock localizes at germline ring canals throughout oogenesis. Loss of Dock leads to a significant reduction in ring canal diameter, and overexpression of Dock causes dramatic defects in ring canal structure and nurse cell multinucleation. The SH2 domain of Dock is required for ring canal localization downstream of Src64 (also known as Src64B), and the function of one or more of the SH3 domains is necessary for the strong overexpression phenotype. Genetic interaction and localization studies suggest that Dock promotes WASp-mediated Arp2/3 activation in order to determine ring canal size and regulate growth.This article has an associated First Person interview with the first author of the paper.

First person – Kara Stark

First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Kara Stark is first author on 'Precise levels of the Drosophila adaptor protein Dreadlocks maintain the size and stability of germline ring canals', published in JCS. Kara conducted the research described in this article while an undergraduate research assistant in Dr Lindsay Lewellyn's lab at Butler University, Indianapolis, IN. She is now a PhD student in the lab of Dr Zhao Zhang at Duke University, Durham, NC, investigating how transposon mobilization interacts with the immune system during development.

The profile of the spinal column in subjects with lumbar developmental spinal stenosis.

The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort. This was a radiological analysis of 2,387 participants who underwent L1-S1 MRI. Means and ranges were calculated for age, sex, BMI, and MRI measurements. Anteroposterior (AP) vertebral canal diameters were used to differentiate those with DSS from controls. Other imaging parameters included vertebral body dimensions, spinal canal dimensions, disc degeneration scores, and facet joint orientation. Mann-Whitney U and chi-squared tests were conducted to search for measurement differences between those with DSS and controls. In order to identify possible associations between DSS and MRI parameters, those who were statistically significant in the univariate binary logistic regression were included in a multivariate stepwise logistic regression after adjusting for demographics. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported where appropriate. Axial AP vertebral canal diameter (p < 0.001), interpedicular distance (p < 0.001), AP dural sac diameter (p < 0.001), lamina angle (p < 0.001), and sagittal mid-vertebral body height (p < 0.001) were significantly different between those identified as having DSS and controls. Narrower interpedicular distance (OR 0.745 (95% CI 0.618 to 0.900); p = 0.002) and AP dural sac diameter (OR 0.506 (95% CI 0.400 to 0.641); p < 0.001) were associated with DSS. Lamina angle (OR 1.127 (95% CI 1.045 to 1.214); p = 0.002) and right facet joint angulation (OR 0.022 (95% CI 0.002 to 0.247); p = 0.002) were also associated with DSS. No association was observed between disc parameters and DSS. From this large-scale cohort, the canal size is found to be independent of body stature. Other than spinal canal dimensions, abnormal orientations of lamina angle and facet joint angulation may also be a result of developmental variations, leading to increased likelihood of DSS. Other skeletal parameters are spared. There was no relationship between DSS and soft tissue changes of the spinal column, which suggests that DSS is a unique result of bony maldevelopment. These findings require validation in other ethnicities and populations. Level of Evidence: I (diagnostic study) Cite this article: Bone Joint J2021;103-B(4):725-733.

To study the outcome of retrograde nailing in distal one-third femoral shaft fractures

Objectives: With antegrade nailing, it is difficult to achieve perfect reduction of distal shaft femur fracture because of mismatch of size of medullary canal. Short juxta-articular segment is under the influence of deforming muscle forces and the large metaphyseal volume does not allow the intramedullary nail to have cortical contact that can aid in the reduction of the fracture. Distal femur fractures typically shorten and displace into recurvatum in the sagittal plane. In the coronal plane, the fractures have a tendency to displace or angulate according to the fracture morphology. This study was performed to assess the outcome of “Distal One-Third Shaft Femur Fracture” with Retrograde Intramedullary Interlocking Nail. Its intraoperative and postoperative complications and ease of surgery using retrograde intramedullary nailing. Using intraoperative time taken for completion of surgery and total number of C-Arm exposures.Materials and Methods: The study will include 30 cases with distal one third shaft femur fractures, who will undergo surgery using retrograde nail. Patients will be followed up for a period of 6 months at 1st, 3rd and 6th month. Patients will be assessed on the basis of Demographic analysis, Mode of injury, Classification of fracture based on AO Classification, Duration of surgery, number of C-ARM exposures, Outcome of fracture, Sagittal/Coronal plane deformity, Limb Length Discrepancy/Rotational, alignment, Range of motion. Pain, functional outcome of knee using lysholm knee score and Complications observed. Results: Two patients shows malalignment rest twenty patients had normal alignment. In our study radiological union was seen in 16(72.7%) patients and nonunion was observed in 6(27.3%) patients.Conclusion: We strongly recommend the use of Retrograde Intramedullary Nail with multiple distal locking options in the patients with distal one-third femoral shaft fractures, keeping the distal end of the nail in subchondral bone.

Clinical and radiological results of indirect decompression after anterior lumbar interbody fusion in central spinal canal stenosis.

Whereas the benefits of indirect decompression after lateral lumbar interbody fusion are well known, the effects of anterior lumbar interbody fusion (ALIF) have not yet been verified. The purpose of this study was to evaluate the clinical and radiological effects of indirect decompression after ALIF for central spinal canal stenosis. In this report, along with the many advantages of the anterior approach, the authors share cases with good outcomes that they have encountered. The authors performed a retrospective analysis of 64 consecutive patients who underwent ALIF for central spinal canal stenosis with instability and mixed foraminal stenosis between January 2015 and December 2018 at their hospital. Clinical assessments were performed using the visual analog scale score, the Oswestry Disability Index, and the modified Macnab criteria. The radiographic parameters were determined from pre- and postoperative cross-sectional MRI scans of the spinal canal and were compared to evaluate neural decompression after ALIF. The average follow-up period was 23.3 ± 1.3 months. All clinical parameters, including the visual analog scale score, Oswestry Disability Index, and modified Macnab criteria, improved significantly. The mean operative duration was 254.8 ± 60.8 minutes, and the intraoperative bleeding volume was 179.8 ± 119.3 ml. In the radiological evaluation, radiological parameters of the cross-sections of the spinal canal showed substantial development. The spinal canal size improved by an average of 43.3% (p < 0.001) after surgery. No major complications occurred; however, aspiration guided by ultrasonography was performed in 2 patients because of a pseudocyst and fluid collection. ALIF can serve as a suitable alternative to extensive posterior approaches. The authors suggest that ALIF can be used for decompression in central spinal canal stenosis as well as restoration of the foraminal dimensions, thus allowing decompression of the nerve roots.

Analysis of Torque and Force Induced by Rotary Nickel-Titanium Instruments during Root Canal Preparation: A Systematic Review

The aim of this review was to provide a detailed literature analysis of torque and force generation during nickel-titanium rotary root canal instrumentation. We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search was performed using in PubMed and in journals for articles published in English from 1987 to June 2020 on studies that investigated dynamic torque and force in vivo or in vitro. We assessed article titles and abstracts to remove duplicates, and the titles and abstracts of the remaining articles were screened for eligibility. Full texts were read to verify eligibility by considering predetermined inclusion and exclusion criteria. Fifty-two out of 4096 studies met the inclusion criteria, from which we identified 26 factors that influence torque or force generation. Factors associated with higher torque or force generation and supported by multiple studies with mostly consistent results included convex triangle cross-sectional design, regressive taper, short pitch length, large instrument size, small canal size, single-length preparation technique, long preparation time, deep insertion depth, low rate of insertion, continuous rotation (torque), reciprocating motion (force), lower rotational speed and conventional alloy. However, several factors are interrelated, which obscured the independent effect of each factor, and there was insufficient scientific evidence supporting the influence of some factors.

An examination of histomorphometric relationships in the anterior and posterior human femoral cortex.

Static cortical bone histomorphometry utilised in forensic age-at-death estimation generally examines only the anterior femoral mid-shaft, as biomechanical strain at the posterior femur is thought to result in increased bone remodelling, osteon density and adversely affect age-at-death estimates. As osteon density increases there is a corresponding decrease in geometric variables, such as osteon area and Haversian canal diameter. The present study tests whether the inverse relationship between osteon density and osteon geometry is reflected in a modern documented Australian sample, and if this relationship differs between the anterior and posterior femoral mid-shaft. The study sample comprises 215 femoral microradiographs (117♂ 98♀) of recorded age (18‒97years) from the Melbourne Femur Reference Collection (MFRC). The following variables were measured in Image J across six 1mm2 regions of interest (ROIs) from the anterior and posterior; mean intact and fragmentary secondary osteon count, osteon population density, osteon and Haversian canal area, perimeter, and diameter. Osteon area was positively correlated with Haversian canal size and shape metrics, and negatively correlated with osteon density. Chronological age was significantly correlated with most variables. There were significant between-group effects between the youngest (18‒34years) and all other age groups (35‒49, 50-74 and 75 + years) for both regions. Our findings support an increased rate of remodelling associated with decreases in osteon geometry in the anterior and posterior femur. Future studies should examine static osteon histomorphometry using anterior and posterior measurements in larger samples of documented age and sex.

Gene therapy via canalostomy approach preserves auditory and vestibular functions in a mouse model of Jervell and Lange-Nielsen syndrome type 2

Mutations in voltage-gated potassium channel KCNE1 cause Jervell and Lange-Nielsen syndrome type 2 (JLNS2), resulting in congenital deafness and vestibular dysfunction. We conducted gene therapy by injecting viral vectors using the canalostomy approach in Kcne1−/− mice to treat both the hearing and vestibular symptoms. Results showed early treatment prevented collapse of the Reissner’s membrane and vestibular wall, retained the normal size of the semicircular canals, and prevented the degeneration of inner ear cells. In a dose-dependent manner, the treatment preserved auditory (16 out of 20 mice) and vestibular (20/20) functions in mice treated with the high-dosage for at least five months. In the low-dosage group, a subgroup of mice (13/20) showed improvements only in the vestibular functions. Results supported that highly efficient transduction is one of the key factors for achieving the efficacy and maintaining the long-term therapeutic effect. Secondary outcomes of treatment included improved birth and litter survival rates. Our results demonstrated that gene therapy via the canalostomy approach, which has been considered to be one of the more feasible delivery methods for human inner ear gene therapy, preserved auditory and vestibular functions in a dose-dependent manner in a mouse model of JLNS2.

Creation of a Custom-Length, Humeral Antibiotic Cement Spacer for Use in Treatment of Shoulder Periprosthetic Joint Infection

Periprosthetic joint infection of the shoulder is a challenging clinical situation to manage owing to the fastidious organisms often present and delayed clinical presentation. While several treatment options have been described, the mainstay of treatment remains a staged revision with the use of a humeral antibiotic cement spacer. Such spacers are commercially available or can be made by hand. When an extended humeral osteotomy is required to remove a well-fixed long stem humeral component, it may be advantageous to place an antibiotic spacer with a stem length approximately as long as the hardware being removed. This technique demonstrates creation of a custom length, humeral antibiotic cement spacer for use in treatment of shoulder periprosthetic joint infection.

Cleft lip and palate cause large variations in size and location of the posterior superior alveolar canal.

The aim of this study was to evaluate the posterior superior alveolar canal (PSAC) in patients with cleft lip and palate (CLP) as compared to patients with no cleft lip and palate (NC) using cone-beam computed tomography (CBCT). This was a retrospective multicenter study based on two steps: (1) evaluating intra- and inter-calibration and (2) detecting the presence or absence of PSAC and its location, diameter, and anastomosis with anterior superior alveolar canal. A total of 300 patients were selected for the study, out of which 150 were categorized as CLP (75 men, 75 women; mean age: 29.8years) and 150 were categorized as NC (75 men, 75 women; mean age: 40.3years). PSAC in patients with CLP and NC was visible in 100% of the cases, in men and women, bilaterally. PSAC location in CLP was middle and upper third of the maxillary sinus as compared to NC (lower third) (chi-squared < 0.001). PSAC mean diameter in CLP was 1.12mm. It was larger compared to 0.6mm in NC (t-test < 0.0001). PSAC location in patients with CLP was predominantly in the middle and upper third of the maxillary sinus, compared with NC. PSAC mean diameter in CLP was 1.12mm. It was larger compared to that of 0.6mm in NC. These anatomical variations in CLP are important and should be acknowledged by surgeons for the following reasons: (1) to perform pre-surgical planning, (2) to avoid bleeding, and (3) to avoid neurosensory alterations.

Association of developmental lumbar spinal canal stenosis and stunting

Objective: To determine a possible relationship between developmental lumbar spinal canal stenosis (DLSS) and stunting. Background: Stunting is due to failure of longitudinal length with shortened long bones. Stunted individuals have failure of growth of long bones implying a possibility of involvement of short and flat bones. The hypothesis in this study is that DLSS is part of a generalized skeletal dysplasia. Materials and Methods: This is a cross-sectional study (CSA) of 400 patients looking at the association of DLSS with stunting. The study compares the size of the spinal canal in individuals with stunting and those without stunting. Stunting was defined according to the WHO/UNICEF criteria of −2SD of the median height of the same population. The participants were divided into two types: those who were deemed stunted and those who were not. DLSS was similarly defined as −2SD of the relevant measured parameter. The study included skeletally mature patients between 18 and 60 years. All syndromic individuals, those with spine tumors and previous spine surgery, were excluded. Results: Four hundred individuals were sampled from a pool of 597 participants. One hundred and eight or 27% were stunted. The stunted individuals had statistically significantly shallow canal depths or anteroposterior diameters (11.2 ± 2.0 mm vs. 14.6 ± 2.6 mm, t(398) = −11.1, P < 0.001), and narrower canal widths (transverse diameters) (14.6 ± 3.3 mm vs. 18.8 ± 4.5 mm, t(398) = −8.1, P < 0.001) and smaller CSAs (134.0 ± 49.4 mm vs. 220.2 ± 82.0, t(398) = −9.4, P < 0.001) when compared to individuals with normal heights. Odds ratio was 10. Conclusions: Stunted individuals have smaller lumbar spinal canals when compared to nonstunted individuals. It can be concluded that developmental lumbar spinal canal stenosis is part of a generalized skeletal dysplasia.

A NOVEL SEMI-AUTOMATIC MEASUREMENT OF THE SEMICIRCULAR CANALS OF THE HUMAN BONY LABYRINTH

The bony labyrinth is an inner ear structure located inside the pyramid of the temporal bone. In skeletal or skeletonized human remains, the region exhibits a remarkably high resistance against a variety of taphonomic factors. A substantial amount of work has been carried out in many scientific domains assessing morphological variations of the bony labyrinth. However, the results of these studies are inconsistent with each other, so researchers remain unable to definitively confirm or reject size and shape dependencies of the bony labyrinth on factors such sex or age. Inadequate methodology and the invasiveness of existing approaches are frequently cited as reasons for these ambiguous results. This paper proposes a new semiautomatic PC-aided approach for quantifying the semicircular canals of the bony labyrinth using CT-generated three-dimensional digital models. A new measurement protocol was established on a sample of 163 bony labyrinths using a step-wise elimination procedure and semi-automatic computerassisted tools. The procedure finally selected as most effective included 39 measurements, which were employed to explore age, sex or side-to-side differences in the shape and size of the semicircular canals. The results exhibit very few sex-related and body-side-specific differences. However, statistically significant differences were observed between subadults and adults, particularly in the canal lumens of the lateral and posterior semicircular canals, where larger values were detected for the adults. This paper presents a novel innovative approach for quantifying the semicircular canals of the bony labyrinth, with the aim of regularizing the methodological pool in this line of research.

Can a different pasta making process preserve the starch’s ultrastructure, increasing its digestibility?

BACKGROUND: Pasta plays an important role in human nutrition, nevertheless its organoleptic, structural and bromatologic properties have not been completely studied. OBJECTIVE: The study aims to compare the ultrastructure pasta cross-sections produced with reduced mechanic stress and low heat exposure technique (Pietro Massi Technology ™) to common samples obtained with traditional technology in order to assess if a different process can alter the ultrastructure of starch and then, its digestibility. METHODS: A comparative study was performed on the ultrastructure of pasta using scanning electron microscopy (S.E.M). 55 were pasta cross-sections made with Pietro Massi technology, 33 were samples from different pasta factory produced using traditional process, for a total of 88 samples analysed. RESULTS: According to an Index based on what it was observed at one slide at S.E.M we classified samples and compared the number of grains, caves and canals visible, their dimensions in μm and average size of grains. The number of grains in group 1 (9.06±5.01) in group 2 (5.71±5.77), in group 3 (5.93±7.65) resulted significative more elevated compared to group 4 (0.73±2.58); in group 1 and group 2 the number of caves observed was higher than group 4. The size in μm of canals resulted significantly more elevated in group 1 than group 3 (p = 0.008), group 2(p = 0.013), and group 4 (p = 0.02). CONCLUSION: The analysis of average size of caves and canals in μm, the number of caves and grains demonstrated in samples obtained with Massi technology elevated values compared to samples obtained with traditional technique. The number of caves, grains and canals visible in the starch surface demonstrate the high quality of this pasta because they likely ensure penetration of water during cooking, facilitating at the same time the penetration of pancreatic amylases during digestion, suggesting a better digestibility in pasta produced according to this methodology.

A Study of Transverse Diameter of The Lumbar Spinal Canal in Plain Radiograph in Population of Telangana, India

Background: The present study was conducted to determine Transverse diameter (inter-pedicular distances) of the lumbar spinal canal measured in plain antero-posterior radiograph of 140 subjects (80 males, 60 females) aged between 20 to 60 years in population of Telangana. Subjects and Methods : The present study was conducted in the department of Anatomy, in a teaching medical college and hospital in Hyderabad, Telangana, India. It comprised of antero-posterior plain radiographs of lumbar spine of 140 subjects, aged between 20 to 60 years. Transverse diameter of the lumbar spinal canal or inter-pedicular distances (IPD), and transverse diameter of the vertebral body was measured using electronic Digital Vernier calipers, and the ratio between transverse diameter of vertebral canal and transverse diameter of the corresponding vertebral body were analyzed. Results: Out of 140 patients, males were 80 and females were 60. The mean inter-pedicular distance (IPD) at L1 was 24.2 mm in males and 23.4 mm in females, and at L5 was 30.2 mm in males and 29.6 mm in females. Mean transverse diameter of lumbar vertebral canal (I.P.D) is minimum at L1 vertebra in both sexes. The maximum values of I.P.D were recorded for vertebra L5 for both sexes. The values of IPD are higher in male population in comparison to female counterparts. The mean width of the vertebral body is gradually increasing from L1 to L5. Ratio between transverse diameter of vertebral canal and transverse diameter of the corresponding vertebral body is seen to be constant (0.6) at all lumbar level in both the sexes. Conclusion: Authors found that there is variation in the size of the lumbar vertebral canal between males and females. Even after the revolution of various imaging techniques like CT Scan, MRI, etc., the plain radiography remains the mainstay of investigative procedure particularly in rural setup.

Do Morphological Changes in the Anterior Mandibular Region Interfere with Standard Implant Placement? A Cone Beam Computed Tomographic Cross-Sectional Study.

Objective To determine the morphological features in the anterior mandibular region, the presence of lingual foramen and canal dimensions in Saudi subjects that would interfere with standard implant placement. Methods CBCT scans of patients seeking implant treatment were examined. Based on the dentition status, patients were categorized into edentulous (group I) and dentulous (group I). On the panoramic view, the distance between the two mental foramina was divided into vertical segments of 10 mm width. In each segment, vertical bone height and buccolingual thickness at three levels (alveolar crest, 5 mm, and 10 mm apical to the crest) were assessed. The lingual foramen prevalence and canal features were assessed as well. Comparisons between the two groups regarding the assessed parameters were performed using the t-test. The percentage of edentulous mandibles with thickness <6 mm corresponding to the standard implant diameter was also calculated. Results Following the inclusion and exclusion criteria, group I consisted of 45 subjects and group II comprised 26 subjects. Bone height and thickness at the crestal level were significantly less in edentulous (I) than dentate mandibles (II) (P < 0.0001). The lingual foramen was detected in 90% of patients. In both groups, males had significantly greater mandibular height than females (P=0.02 and 0.005). At the crestal level, the thickness was <6 mm in 50% of the anterior mandibular segments. Conclusion Half of the edentulous patients may receive normal size implants in the anterior interforaminal segments, while the other half will be limited to narrow implants (3.5 mm and less). The lingual foramen location, canal size, and position may represent another limitation for implant placement in that segment.

Fully Implanted Prostheses for Musculoskeletal Limb Reconstruction After Amputation: An In Vivo Feasibility Study.

Previous prostheses for replacing a missing limb following amputation must be worn externally on the body. This limits the extent to which prostheses could physically interface with biological tissues, such as muscles, to enhance functional recovery. The objectives of our study were to (1) test the feasibility of implanting a limb prosthesis, or endoprosthesis, entirely within living skin at the distal end of a residual limb, and (2) identify effective surgical and post-surgical care approaches for implanting endoprostheses in a rabbit model of hindlimb amputation. We iteratively designed, fabricated, and implanted unjointed endoprosthesis prototypes in six New Zealand White rabbits following amputation. In the first three rabbits, the skin failed to heal due to ishemia and dehiscence along the sutured incision. The skin of the final three subsequent rabbits successfully healed over the endoprotheses. Factors that contributed to successful outcomes included modifying the surgical incision to preserve vasculature; increasing the radii size on the endoprostheses to reduce skin stress; collecting radiographs pre-surgery to match the bone pin size to the medullary canal size; and ensuring post-operative bandage integrity. These results will support future work to test jointed endoprostheses that can be attached to muscles.

Cone beam computed tomography analysis of accessory canals of the canalis sinuosus: A prevalent but often overlooked anatomical variation in the anterior maxilla

Statement of problemAccessory canals of the canalis sinuosus, a bony canal carrying the anterior superior alveolar nerve and vessels, can often be present but overlooked in the anterior maxilla. Dental implant placement in this area may damage neurovascular branches if this anatomic variation is not carefully identified, resulting in unexpected complications. PurposeThe purpose of this retrospective study was to identify accessory canals of the canalis sinuosus and analyze their relationship to the terminal canalis sinuosus and anterior maxilla in Chinese patients to provide a warning for surgeons operating in the anterior maxilla. Material and methodsCone beam computed tomography (CBCT) scans of 1007 Chinese patients were examined to identify the prevalence and size of accessory canals with at least 1.0-mm diameter. Axial position of this canal was classified referring to the nasal cavity and adjacent teeth. Its sagittal position was determined by the distance from the bifurcation site of canalis sinuosus to the buccal alveolar crest and the distance from the canal opening to the palatal alveolar crest. Diameter of the terminal canalis sinuosus, distance from the terminal canalis sinuosus to the buccal alveolar crest, and anterior maxillary volume were measured on all scans. Binary logistic regression and the Spearman rank correlation coefficient were used for prevalence and diameter analysis. ResultsThe prevalence of the accessory canal was 36.9%, positively correlated the anterior maxillary volume (OR 1.408) and negatively correlated with the distance from the terminal canalis sinuosus to the buccal alveolar crest (OR 0.921). Average diameter of such canal was 1.1 ±0.1 mm, significantly higher in men, positively correlated with the diameter of terminal canalis sinuosus (rs=0.163) and the distance from the canal opening to the palatal alveolar crest (rs=0.192). All accessory canals started below the buccal cortical bone, 19.3 ±2.7 mm away from the buccal alveolar crest. There were 61.9% accessory canals opened between the central and the lateral incisors. Openings here and in the central incisor region were closer to the alveolar crest than that between the lateral incisor and the canine (P<.05). ConclusionsAccessory canals of the canalis sinuosus have high prevalence in the anterior maxilla in a Chinese population. Large anterior maxillary volume has been demonstrated as a risk factor associated with the presence of such canals. The region between the central and the lateral incisors was a predominant location. Openings in this region were closer to the alveolar crest than those between the lateral incisor and the canine.

Dr. G. E. Herman, Chairman of the London Midwifery Society — On the change in size of the cervical canal during menstruation. (The British Medic. Journ., 14 / VII, 1894, p. 70). About changes in the canal of the uterine cervix during menstruation

Having reminded the members of the London Midwifery society of the existing disagreement regarding the spatial change of the cervical canal during menstruation, which, according to some, shrinks and swells its mucous membrane, and according to othersexpands, Herman outlined the results of his research, namely: 1) During menstruation, there is a slight dilation of the canal. 2) the largest amount of expansion is closed on the 3rd or 4th day of regulation. 3) dilation is observed equally in women with abundant or scanty menstruation, with or without pain, and there is no mutual relationship between these phenomena and the degree of dilation.

Stressed volume estimated by finite element analysis predicts the fatigue life of human cortical bone: The role of vascular canals as stress concentrators.

The fatigue life of cortical bone can vary several orders of magnitude, even in identical loading conditions. A portion of this variability is likely related to intracortical microarchitecture and the role of vascular canals as stress concentrators. The size, spatial distribution, and density of canals determine the peak magnitude and volume of stress concentrations. This study utilized a combination of experimental fatigue testing and image-based finite element (FE) analysis to establish the relationship between the stressed volume (i.e., volume of bone above yield stress) associated with vascular canals and the fatigue life of cortical bone. Thirty-six cortical bone samples were prepared from human femora and tibiae from five donors. Samples were allocated to four loading groups, corresponding to stress ranges of 60, 70, 80, and 90MPa, then cyclically loaded in zero-compression until fracture. Porosity, canal diameter, canal separation, and canal number for each sample was quantified using X-ray microscopy (XRM) after testing. FE models were created from XRM images and used to calculate the stressed volume. Stressed volume was a good predictor of fatigue life, accounting for 67% of the scatter in fatigue-life measurements. An increase in stressed volume was most strongly associated with higher levels of intracortical porosity and larger canal diameters. The findings from this study suggest that a large portion of the fatigue-life variance of cortical bone in zero-compression is driven by intracortical microarchitecture, and that fatigue failure may be predicted by quantifying the stress concentrations associated with vascular canals.

Does the Size or Location of Lumbar Disc Herniation Predict the Need for Operative Treatment?

Study Design:Retrospective cohort study.Objective:The goal of this study was to determine whether the absolute size (mm2), relative size (% canal compromise), or location of a single-level, lumbar disc herniation (LDH) on axial and sagittal cuts of magnetic resonance imaging (MRI) were predictive of eventual surgical intervention.Methods:MRIs of 89 patients were reviewed, and patients were split into groups based on type of management received (34 nonoperative vs 55 microdiscectomy). Radiographic characteristics—including size of disc herniation (mm2), size of spinal canal (mm2), location of herniation on axial (central, paracentral, foraminal) and sagittal (disc level, suprapedicle, pedicle, infrapedicle) planes, and type of herniation (bulge, protrusion, extrusion, sequestration)—were measured by 2 independent, orthopedic spine fellows and compared between groups via univariate and multivariate analyses.Results:The operative group showed a significantly higher percentage of canal compromise (39.5% vs 31.1%, P = .001) compared to the nonoperative group. Multiple logistic regression analysis showed higher odds of eventual operative intervention for a disc protrusion (odds ratio [OR] 6.30 [1.99, 19.86], P = .002) or disc extrusion (OR 11.5 [1.63, 81.2], P = .014) for Rater 1 and a higher odds of eventual surgical management for a paracentral location for both Rater 1 and Rater 2 (OR = 3.39 [1.25, 9.22], P = .017, and OR = 5.46 [1.77, 16.8], P = .003, respectively).Conclusions:Disc herniations in a paracentral location were more likely to undergo operative treatment than those more centrally located, on axial MRI views.