Posterior Boundary Research Articles

TBX3 is essential for establishment of the posterior boundary of anterior genes and upregulation of posterior genes together with HAND2 during the onset of limb bud development.

During limb bud formation, axis polarities are established as evidenced by the spatially restricted expression of key regulator genes. In particular, the mutually antagonistic interaction between the GLI3 repressor and HAND2 results in distinct and non-overlapping anterior-distal Gli3 and posterior Hand2 expression domains. This is a hallmark of the establishment of antero-posterior limb axis polarity, together with spatially restricted expression of homeodomain and other transcriptional regulators. Here, we show that TBX3 is required for establishment of the posterior expression boundary of anterior genes in mouse limb buds. ChIP-seq and differential gene expression analysis of wild-type and mutant limb buds identifies TBX3-specific and shared TBX3-HAND2 target genes. High sensitivity fluorescent whole-mount in situ hybridisation shows that the posterior expression boundaries of anterior genes are positioned by TBX3-mediated repression, which excludes anterior genes such as Gli3, Alx4, Hand1 and Irx3/5 from the posterior limb bud mesenchyme. This exclusion delineates the posterior mesenchymal territory competent to establish the Shh-expressing limb bud organiser. In turn, HAND2 is required for Shh activation and cooperates with TBX3 to upregulate shared posterior identity target genes in early limb buds.

Robust and accurate corneal interfaces segmentation in 2D and 3D OCT images.

Segmentation of corneal layer interfaces in optical coherence tomography (OCT) images is important for diagnostic and surgical purposes, while manual segmentation is a time-consuming and tedious process. This paper presents a novel technique for the automatic segmentation of corneal layer interfaces using customized initial layer estimation and a gradient-based segmentation method. The proposed method was also extended to three-dimensional OCT images. Validation was performed on two corneal datasets, one with 37 B-scan images of healthy human eyes and the other with a 3D volume scan of a porcine eye. The approach showed robustness in extracting different layer boundaries in the low-SNR region with lower computational cost but higher accuracy compared to existing techniques. It achieved segmentation errors below 2.1 pixels for both the anterior and posterior layer boundaries in terms of mean unsigned surface positioning error for the first dataset and 2.6 pixels (5.2 μm) for segmenting all three layers that can be resolved in the second dataset. On average, it takes 0.7 and 0.4 seconds to process a cross-sectional B-scan image for datasets one and two, respectively. Our comparative study also showed that it outperforms state-of-the-art methods for quantifying layer interfaces in terms of accuracy and time efficiency.

Proposals for the delineation of neck clinical target volume for definitive Radiation therapy in patients with oral/ oropharyngeal squamous cell cancer based on lymph node distribution

Purpose/Objective(s)To establish the distribution pattern of cervical lymph node metastasis (LNM) and propose optimized clinical target volume (CTV) boundaries specific to oral/ oropharyngeal squamous cell cancer (OSCC/OPSCC). Materials/Methods531 patients with pathologically confirmed OSCC/OPSCC were enrolled from January 2013 to June 2022. Patients were stratified into two groups based on the minimal distance from the lesion's edge to the body's midline: ≤1 cm or > 1 cm. The geometric center of cervical metastatic LN was marked on a template CT. LN distribution probability maps were established. The relationships between the LN distribution and consensus guidelines were analyzed to propose modifications for CTV boundaries specific to OSCC/OPSCC. ResultsA total of 1962 positive LNs were enrolled. Compared with the > 1 cm group, the ≤ 1 cm group has following feature tendencies: male smokers, younger, median organs, large gross lesion, infiltrative growth pattern, contralateral LNM. The most frequently involved level of LNM was ipsilateral II, but ipsilateral Ib had the highest involvement rate in the > 1 cm OSCC group. In addition, tongue cancer had a higher incidence of LN extranodal extension (ENE), which mainly distributes in ipsilateral level II. The skip metastasis was prone to from level III to Vb (3.5 %) in LN(+)/ENE (-), and level Ib to VIa (3.7 %) in LN(+)/ENE (+). Accordingly, we proposed the following modifications: 1. only including lateral and posterior margin of submandibular gland within 5 mm; 2. retracting posterior boundary of level II to front edge of levator scapula muscle, and descending the upper boundary to transverse process of C2 vertebra only for OSCC; 3. including posterior third of thyroglossal muscle or anterior edge of sternocleidomastoid muscle; 4. sparing level Va in case of only level II involvement; 5. including upper area of the thyroid cartilage plate in case of level Ib LN(+)/ENE (+); 6. sparing level VIIa is considered. ConclusionThis is the first description of LN topographic spread patterns for OSCC/OPSCC. Modified CTV for prophylactic irradiation was proposed to spare the organs at risk and minimize adverse effects.

Modified medial gastrocnemius myocutaneous flap with extended anterior, inferior and/or posterior boundaries: Anatomical observation and report of a clinical series of 33 flaps

IntroductionReports on medial gastrocnemius myocutaneous (MGM) flaps with extended inferior and posterior boundaries are rare, and information about the MGM flaps with extended anterior boundaries is unavailable. Thus, this study aimed to investigate the vascular anatomical basis and clinical reliability of the modified MGM flap with extended anterior, inferior and/or posterior boundaries. MethodsFive fresh lower limb specimens from patients with recurrent tumours in the thigh were immediately irrigated and perfused. The stripped integuments were radiographed. The pretibial skin was equally divided into nine zones. The reconstruction outcomes of the modified MGM flaps were documented in 33 patients. ResultsTrue anastomotic connections existed among the branches of the saphenous artery, the perforator from the inferior medial genicular artery and 3–5 (mean, 4.5) perforators from the posterior tibial artery in the upper two-thirds of the leg. A total of 33 modified MGM flaps were applied. The anterior margins of 26 modified flaps with extended anterior boundaries exceeded the medial edge of the tibia by 1.0–4.5 cm (mean, 2.1 cm). Fourteen modified MGM flaps were used to repair the defects involving the lower third leg, whose distal edges were located in the seventh (n = 8) or eighth (n = 6) zone. A 1–169-month (median, 9 months) follow-up was conducted for 33 patients. Of the 33 flaps, 29 (87.9 %) survived completely, partial necrosis occurred in four flaps with extended anterior (n = 2) or inferior (n = 2) boundaries. ConclusionsMultiple source vessels are the vascular anatomical basis of the modified MGM flap with extended anterior, posterior and/or inferior boundaries. The modification of the MGM flap is feasible and reliable, broadening the applicable scope of the flap. The modified MGM flap can be applied to repair more distal, wider and larger-area defects with a simpler design and procedure.

The boundary of posterior to level V region and the theoretical feasibility of irradiation dose reduction of level Va in nasopharyngeal carcinoma

The lymph node involvement in the posterior to level V (PLV) region is mainly observed in nasopharyngeal carcinoma (NPC). Recently, we have reported the distribution of metastatic lymph nodes in the PLV region and there are correlations between the neck node levels (NNL) of NPC, but what is the boundary of the PLV region and how to delineate it remains unclear, and we further to elaborate whether the bilateral level Va should be covered as intermediate-risk nodal regions (CTVn2, about 60 Gy equivalent) for all T and N categories based on these correlations. A total of 1021 consecutive NPC patients with N1-3 stage from January 2012 to December 2020 were reviewed. The lymph node metastasis level of each patient was evaluated according to the updated guidelines proposed in 2013. According to the distribution pattern of lymph node metastasis and the anatomical structure in the PLV region, the boundaries of PLV region was delineated, and whether it is appropriate to cover the bilateral level Va as CTVn2 for all the NPC patients was further discussed. The correlations of level Va with other NNL were studied using logistic regression model. The cranial boundary of PLV region is the caudal border of cricoid cartilage, the caudal boundary is the plane serratus anterior muscle begins to appear, the anterior boundary is the anterior border of trapezius, and the posterior boundary is the convergence of levator scapulae and trapezius. Laterally, the PLV region is limited by the medial edge of trapezius and medially by the lateral surface of levator scapulae. The nodal spread in level Va is based on the lymph node metastasis of level IIb in NPC. The PLV region is a missing NNL of head and neck tumors, especially in NPC. The proposed boundaries of the PLV region can provide a preliminary proposal for the further revision of NNL in head and neck tumors. It is theoretically feasible to reduce the prophylactic irradiation dose of the bilateral level Va in patients with N0 stage or with isolated metastases in level VIIa.

Influence of Digit Sucking Habit on Masseter Muscle Thickness and Upper Airway Dimensions in Nigerian Children

Background: Digit sucking habit (DSH) generates functional forces that can influence craniofacial morphology. Although the dental effects have been widely reported, its influence on the masseter muscle thickness (MMT) and upper airway (UA) dimensions is not well known.
 
 Methods: Thirty (30) children selected from the orthodontic clinic (OAUTHC), with a DSH were matched with a group of 30 children without a DSH. Each group comprised of 16 males and 14 females. Ultrasonographic evaluation of the masseter muscle (MM) was performed to measure the left and right MMT in the relaxed and contracted states. Lateral cephalometric radiographs were obtained and 6 UA variables were measured on the x-ray. Data was analysed using SPSS version 20.0. Statistical significance was set at p<0.05.
 Inferential statistics was done using independent sample t test to compare means.
 Results: Participants in the DS group had a mean age of 7.7 ± 2.2 years, whereas those in the non-DS group had a mean age of 8.1 ± 2.1 years. The MM was generally thicker among the DS group, both in the contracted and relaxed states when compared with the non-DS group, but these differences were not statistically significant (p>0.05). The mean measurement of the width of the nasopharynx (P1) was significantly decreased among the DS group when compared with the non-DS group (p<0.05). There was no statistically significant difference in the mean values for the width of the oropharynx (P2), hypopharynx (P3), soft palate length (PNS-U1) and thickness (MPT) and the posterior bony boundary of the nasopharynx (PNS-Ba) between both groups. (p>0.05).
 Conclusion: Digit sucking habit caused a statistically significant narrowing of the width of the nasopharynx (p<0.05). The MMT did not differ significantly between the DS and non-DS groups both in the relaxed and contracted states.

A Radiation Therapy Contouring Atlas for Delineation of the Level I-II Axilla in the Prone Position

When patients are treated prone for whole breast irradiation (WBI), the axilla typically receives less dose than when patients are treated with WBI in the supine position. There are situations, however, where the axilla is a target as in a situation where the physician intends to treat with "high tangents" to provide good coverage of both the breast and level I-II axilla. In these scenarios, ideal target delineation when the patient is in the prone position is not well-defined. While different consensus guidelines exist for delineation of the nodal areas in the supine position, to our knowledge there are no contouring guidelines for the regional nodes in the prone position based on bone, skin, vascular and muscle landmarks. Forty-three patients treated with high tangents in the prone position from 2012-2018 were identified as representative cases. The level I and II regional nodal contours from the Radiation Therapy Oncology Group (RTOG) breast cancer atlas were adapted for prone position by a radiation oncologist and a breast radiologist based on anatomic considerations and changes observed from supine to prone positioning on diagnostic imaging. The revised nodal contours were reviewed by an expanded expert multidisciplinary panel including additional breast radiation oncologists and surgical oncologists to delineate the level I and II axilla on noncontrast computed tomography (CT) scans. We adapted the RTOG breast cancer atlas, supported by detailed figures, in order to create a CT based atlas of the level I and II axillary lymph node stations in the prone position. For the level I axilla, the cranial and caudal anatomic boundaries remain unchanged. With transition to the prone position from supine, tenting of the pectoralis major occurs displacing the muscle from the chest wall and shifting the axillary space anteromedial to the lateral border of the pectoralis major. Therefore, the anterior boundary is now defined by the plane of the anterior extent of the pectoralis major to skin. The medial boundary is defined by the plane of the lateral border of the pectoralis major and pectoralis minor including to ribs and intercostal muscles. The lateral boundary is defined by the skin, cropped by 5mm. The posterior boundary is defined by the plane of the anterior surface of the latissimus dorsi and subscapularis muscle to skin. For the level II axilla, the cranial, posterior, medial and lateral boundaries remain unchanged. With transition from supine to prone, the axilla exhibits an anterolateral shift, now laterally abutting the lateral border of the pectoralis minor. The anterior boundary is now defined as the posterior aspect of the pectoralis major muscle. The caudal boundary is where the pectoralis minor inserts into ribs. The adaptations to the RTOG breast cancer atlas for prone positioning will enable radiation oncologists to more accurately target the level I and II axilla when treating patients prone in whom the axilla is a target in addition to the breast.

Proposals for the Delineation of Neck Clinical Target Volume Specific to Oral Squamous Cell Cancer Based on Lymph Node Distribution

To establish the regional lymph node (LN) distribution probability map and draw the neck clinical target volume specific to oral squamous cell cancer (OSCC). A total of 293 patients with pathologically proven OSCC were enrolled from Jan 2014 to Jun 2022. The patients were divided into two groups according to the ≤1 cm or>1 cm of minimal distance from the lesion's edge to the midline of body. The center point of the LNs with a minimal axial diameter of ≥10 mm was marked on a single treatment planning computed tomography scan. The neck LN levels I to X were based on 2013 updated international consensus guidelines. LN distribution probability maps were established. The relationships between the LN distribution and consensus guidelines were analyzed to propose modifications for clinical target volume boundaries specific to OSCC. A total of 1033 LNs were marked. Compared with the >1 cm group, The ≤1 cm group has following feature tendencies: strong addiction to smoking and drinking, predilection for tongue and oral floor cancer, larger primary lesion with mainly infiltrative growth pattern, more frequent extra-nodal extension with mainly contralateral LNs. For the ≤1cm group, the distribution probability of LNs was: ipsilateral II (42.67%), ipsilateral Ib (17.35%), contralateral II (11.18%), ipsilateral III (8.74%), contralateral Ib (7.46%), Ia (6.43%). The other group was: ipsilateral Ib (43.14%), ipsilateral II (37.64%), contralateral Ib (4.31%), ipsilateral III (3.92%), contralateral II (3.53%), Ia (0.78%). Accordingly, the proposals for the delineation of neck clinical target volume were: 1. the inferior boundary of level Ia extends until the level of the thyroid cartilage plate; 2. the upper boundary of level Ib descends to the level of the mandibular angle, and the inner posterior boundary only includes the lateral and posterior margin of the submandibular gland within 5mm; 3. the upper boundary of level II changes to the transverse process of the second cervical vertebra, and the posterior boundary retracts to the posterior edge of the levator scapula. 4. the anterior inner border of level IVa contains only the internal jugular arteriovenous sheath. This is the first description of LN topographic spread patterns for OSCC. Optimization of CTV delineation is helpful to improve the treatment outcome and reduce adverse events.

Pharyngeal airway subdivisions in 3-dimensional analysis: Differences between anterior and posterior anatomic boundaries

This study aimed to evaluate if there were differences between anterior and posterior anatomic boundaries used for the 3-dimensional determination of pharyngeal airway. The sample included 150 cone-beam computed tomography scans from healthy patients divided according to (1) age: 6-11, 12-16, and ≥16 years; (2) sex: female and male; (3) anteroposterior skeletal pattern: Class I, II, and III; (4) vertical pattern: brachyfacial, mesofacial, and dolichofacial; and (5) craniocervical inclination (CCI): natural head posture, head flexion, and head extension. Anatomic regions were created to determine the correspondences between structures anteriorly and posteriorly to the pharyngeal airway. The location of the epiglottis, vallecula, hyoid, C2, and C3 were statistically different according to the CCI, and the location of vallecula, C3, and C4 were different according to sex. However, no statistically significant differences were observed between the frequencies of anterior and posterior anatomic region locations among age and different anteroposterior and vertical skeletal patterns. Posterior landmarks tend to be located below the anterior ones; consequently, the anatomic subregion they define will also be located below. Anterior and posterior structures and vertical and anteroposterior skeletal patterns may determine upper airway limits regardless of age. However, the studies must be paired according to sex, and CCI must be standardized.

DIAGNOSTIC ACCURACY OF CONTRAST-ENHANCED ULTRASOUND TO DIFFERENTIATE BENIGN AND MALIGNANT BREAST LESIONS

Cancer of the breast is caused by a cluster of abnormal breast cells that continue to divide and spread throughout the breast. These cells eventually aggregate as a lump in the affected breast. If the cancerous tumor is not treated, the cancer cells may spread to other areas of the body through a process known as metastasis. A metastasis may develop in the lymph nodes located in the axilla or those located above the scapula. In addition, cancer cells have the ability to colonize the bones, lungs, liver, skin, and even the space directly under the skin. Cancer of the breast tissue is a malignancy that can start from either the ductal or lobule epithelium of the breast. Breast cancer is the most common kind of cancer in women. The ability of ultrasonography to identify cystic masses is one of the technology's many strengths. According to BIRADS, the American College of Radiology has also developed a standardized language for the reading and reporting of ultrasounds, which is quite similar to the language used for mammography. Shape of the mass, borders, orientation, kind of posterior acoustic, lesion boundaries, and echo pattern were the characteristics that were described. CEUS is an imaging technology that evaluates breast lesions by analyzing their qualitative qualities as well as their quantitative aspects. The detection of lymphatic channels and sentinel lymph nodes can be done using this method, and it is practical and effective.

Clinicopathological features of corneal invasion by filtering bleb

PurposeTo describe the clinicopathological characteristics and explore the possible etiology of cornea invasion by filtering bleb (CIFB) after filtering surgery.MethodsWe reviewed 22 patients treated for CIFB between March 2005 and March 2022. The patients were followed up for more than 1 year. Slit-lamp examination, optical coherence tomography (OCT), ultrasound biomicroscopy, and histopathological examination were performed to observe the morphology of the bleb and depth of corneal invasion. Depending on the severity of the lesion, treatments consisting of local massage, acupuncture separation, or surgical resection were administered.ResultsThe mean age of the patients was 56.3 ± 8.8 years. All patients underwent filtering surgery in the moderate or advanced stage of glaucoma. The filtering bleb was closely connected with the cornea, and its posterior boundary was locally adhered. Forward displacement of the internal opening of the filtering bleb was found in 4 of 7 surgically treated patients. OCT and pathological examination showed that the filtering blebs invaded the corneal stroma. Removal of the adhesion of the posterior boundary of the filtering bleb by different treatment methods successfully improved the patients’ conditions.ConclusionFiltering blebs can invade the corneal stroma. Adhesion of the posterior boundary and forward displacement of the internal opening of the filtering bleb are the possible causes of CIFB. Removal of the adhesion of the posterior boundary of the filtering bleb can halt the progression of CIFB.

Assessment of the distribution and volume of air chambers around the inner auditory canal on high-resolution computed tomography scans of the temporal bone.

Assessment of the distribution and volume of air chambers around the inner auditory canal on high-resolution computed tomography scans of the temporal bone.

Anatomical Step-by-Step Dissection of Midline Suboccipital Approaches to the Fourth Ventricle for Trainees: Surgical Anatomy of the Telovelar, Transvermian, and Superior Transvelar Routes, Surgical Principles, and Illustrative Cases.

Introduction Safe, effective access to the fourth ventricle for oncologic resection remains challenging given the depth of location, restricted posterior fossa boundaries, and surrounding eloquent neuroanatomy. Despite description in the literature, a practical step-by step dissection guide of the suboccipital approaches to the fourth ventricle targeted to all training levels is lacking. Methods Two formalin-fixed, latex-injected specimens were dissected under microscopic magnification and endoscopic visualization. Dissections of the telovelar, transvermian, and supracerebellar infratentorial-superior transvelar approaches were performed by one neurosurgery resident (D.D.D.), under guidance of senior authors. The dissections were supplemented with representative clinical cases to highlight pertinent surgical principles. Results The telovelar and transvermian corridors afford excellent access to the caudal two-thirds of the fourth ventricle with the former approach offering expanded access to the lateral recess, foramen of Luschka, adjacent skull base, and cerebellopontine angle. The supracerebellar infratentorial-superior transvelar approach reaches the rostral third of the fourth ventricle, the cerebral aqueduct, and dorsal mesencephalon. Key steps described include positioning and skin incision, myofascial dissection, burr hole and craniotomy, durotomy, the aforementioned transventricular routes, and identification of relevant skull base landmarks. Conclusion The midline suboccipital craniotomy represents a foundational cranial approach, particularly for lesions involving the fourth ventricle. Operatively oriented resources that combine stepwise neuroanatomic dissections with representative cases provide a crucial foundation for neurosurgical training. We present a comprehensive guide for trainees in the surgical anatomy laboratory to optimize familiarity with fourth ventricle approaches, mastery of relevant microsurgical anatomy, and simultaneous preparation for learning in the operating room.

Mandibular Fossa Approach to Petroclival and Anterior Pontine Lesions.

Objective To describe the anatomy related to a novel approach to the petroclival region through the mandibular fossa for the treatment of petroclival and anterior pontine lesions. Design Five dry skulls were examined for surgical approach. Three adult cadaveric heads underwent bilateral dissection. One cadaveric head was evaluated with computed tomography after dissection. Setting This study was performed in an academic medical center. Participants Neurosurgical anatomy researchers performed this study using dry skulls and cadaveric heads. Main Outcome Measurements This was a proof-of-concept anatomical study. Results The mandibular fossa approach uses a vertical preauricular incision above the facial nerve branches. Removal of the temporomandibular joint exposes the mandibular fossa. The anterior boundary is the mandibular nerve at the foramen ovale, and the posterior boundary is the jugular foramen. The chorda tympani, eustachian tube, and tensor tympani muscle are sectioned. The carotid artery is transposed out of the petrous canal, and a petrosectomy is performed from Meckel's cave to the foramen magnum and anterior occipital condyle. Dural opening exposes the anterior pons, vertebrobasilar junction, bilateral vertebral arteries, and the ipsilateral anterior and posterior inferior cerebellar arteries. At completion, the temporomandibular joint is reconstructed with a prosthetic joint utilizing a second incision along the mandible. Conclusions The mandibular fossa approach is a new trajectory to the petroclival region and the anterior pons. It combines the more anterior angle of endoscopic approaches along with the enhanced control of open approaches. Further study is necessary before this approach is used clinically.

Safe Region of Craniotomy to Access the Cerebellopontine Region by Retrosigmoid Approach: A Radiological and Anatomical Study.

Accurately positioning the sigmoid sinus (SS), transverse sinus (TS), and vertebral artery (VA) is significantly important during the retrosigmoid (RS) approach. This study aimed to use emissary vein and digastric point as landmarks in high-resolution computer topographic image to locate the SS, TS, and VA to help surgeons to avoid injuring these vascular structures during RS craniotomy. Computed topographic (CT) angiography images of 107 individuals were included, the measurement was performed on coronal, sagittal, and axis planes after the multiplanar reformation. Distance from the emissary vein and digastric point to the posterior boundary of the SS, inferior boundary of the TS were measured by CT angiography preoperatively and in the skull intraoperatively. The VA was also located by emissary vein and digastric point. No significant difference was identified between the distances measured in the CT and skull. Our findings provide anatomical information for locating the boundary of the SS, TS, and V3-VA based on the fixed bony landmarks. Verified by skull measurement, high-resolution CT scan is a cost-effective and reliable tool for identifying the location of the arteries and sinus, which could be widely used to guarantee the safety of RS approach craniectomy.

En Face OCT Detects Preretinal Abnormal Tissues Before and After Internal Limiting Membrane Peeling in Eyes with Macular Hole

To assess preretinal abnormal tissue (PAT) using en face OCT in eyes with idiopathic macular holes (MHs). Retrospective, observational study. Patients with MH who received 6× 6-mm spectral-domain-OCT scans. Preretinal abnormal tissue was detected by en face OCT images with a custom slab, defined with an anterior boundary of 6 μm anterior to the internal limiting membrane (ILM) and a posterior boundary at 3 μm posterior to the ILM. The PAT was defined as any abnormal tissues observed in en face OCT. Characteristics of preoperative and postoperative PAT. Sixty eyes with MH from 60 patients were included. Fifty-one eyes underwent preoperative analysis, and 46 eyes underwent postoperative examination. Before surgery, 48 (94%) eyes had a mean (standard deviation [SD]) PAT of 6.6 (9.8) mm2. The corresponding cross-sectional OCT showed PAT consisting of epiretinal proliferation, epivascular glia, and a preretinal hyperreflective band. Preretinal abnormal tissue was contiguous to the hole (peri-MH PAT) in 12 eyes (24%), whereas others (36 eyes, 76%) had a scattered distribution (extrafoveal PAT). The area of PAT was greater in eyes with a peri-MH PAT than in eyes with an extrafoveal PAT (P < 0.0001). Compared to the eyes with the extrafoveal PAT, the eyes with the peri-MH PAT were associated with men (P= 0.0059) and worse baseline visual acuity (VA) (P= 0.0002). In eyes with ILM peeling (42 eyes), postoperative PAT proliferation was observed from the edge of the ILM peeling toward the periphery over a 1-year follow-up. The mean (SD) area of PAT at 2 weeks after surgery was 3.4 (3.6) mm2 and increased to 12.1 (6.4) mm2 at 12 months (P < 0.0001). However, no PAT increase was observed in 4 eyes that underwent vitrectomy without ILM peeling. The postoperative PAT size was not associated with the postoperative VA. En face OCT revealed PAT in most eyes with MHs. Peri-MH PAT was associated with worse VA and was seen more frequently in male patients. Postoperative PAT proliferation may be triggered by ILM peeling, but it is not associated with worse VA.

Dynamic stability in runners with and without plantar fasciitis

BackgroundPlantar fasciitis (PF) is a common overuse injury experienced by runners. PF may decrease the ability of the plantar fascia to create tension and reduce stability of the foot. Stability of the foot is necessary for whole-body dynamic stability during running which consists of cyclical periods of single leg stance. Given that a major risk factor for running-related injury is previous injury, evaluating dynamic stability in runners with PF, runners with resolved PF, and healthy runners may elucidate differences between these individuals and clarify risk for secondary injury in these groups. Research questionIs dynamic stability reduced in runners with PF and runners with resolved PF compared to healthy runners? MethodsThirty runners were recruited for this retrospective comparative study based on mileage and injury status: current PF (PF), resolved PF (RPF), or healthy (CON). Kinematic and kinetic data were collected during running and dynamic stability was determined by time-to-contact (TtC) analysis for early, mid, and late stance to the anterior, posterior, medial, and lateral boundary of the foot. Dynamic stability was compared between groups one-way ANOVAs (α = 0.05) and Tukey post-hoc tests conducted when appropriate. Cohen’s d effect sizes (d) were reported for all TtC comparisons (small = 0.20, medium = 0.50, large = 0.80). ResultsTtC values were shorter in PF compared to the other groups to all boundaries during mid-stance. TtC was significantly greater in PF compared to RPF to the anterior boundary during late stance. SignificanceShorter TtC observed in PF compared to the other groups during midstance may indicate reduced dynamic stability during the most stable portion of running which may lead to increased injury risk.

Eye-specific 3D modeling of factors influencing oxygen concentration in the lamina cribrosa

Our goal was to identify the factors with the strongest influence on the minimum lamina cribrosa (LC) oxygen concentration as potentially indicative of conditions increasing hypoxia risk. Because direct measurement of LC hemodynamics and oxygenation is not yet possible, we developed 3D eye-specific LC vasculature models. The vasculature of a normal monkey eye was perfusion-labeled post-mortem. Serial cryosections through the optic nerve head were imaged using fluorescence and polarized light microscopy to visualize the vasculature and collagen, respectively. The vasculature within a 450 μm-thick region containing the LC – identified from the collagen, was segmented, skeletonized, and meshed for simulations. Using Monte Carlo sampling, 200 vascular network models were generated with varying vessel diameter, neural tissue oxygen consumption rate, inflow hematocrit, and blood pressures (arteriole, venule, anterior boundary, and posterior boundary). Factors were varied over ranges of baseline ±20% with uniform probability. For each model we first obtained the blood flow, and from this the neural tissue oxygen concentration. ANOVA was used to identify the factors with the strongest influence on the minimum (10th percentile) oxygen concentration in the LC. The three most influential factors were, in ranked order, vessel diameter, neural tissue oxygen consumption rate, and arteriole pressure. There was a strong interaction between vessel diameter and arteriole pressure whereby the impact of one factor was larger when the other factor was small. Our results show that, for the eye analyzed, conditions that reduce vessel diameter, such as vessel compression due to elevated intraocular pressure or gaze-induced tissue deformation, may particularly contribute to decreased LC oxygen concentration. More eyes must be analyzed before generalizing.

Trans-Nasion-Complex Approach for Endoscopic Modified Lothrop Procedure: Conception, Anatomy, and Technique

BackgroundThe endoscopic modified Lothrop procedure (EMLP) is an important procedure used to address frontal and anterior skull-base lesions. Two techniques were established, namely, the inside-out approach and the outside-in approach. The former technique take the frontal recess and the first olfactory filament (FOF) as key landmarks while the latter use the FOF as posterior boundary. In some cases, however, these two landmarks are not available. Therefore, we supplement the outside-in approach and named it trans-nasion-complex approach (TNCA) for EMLP that can be performed without locating these two landmarks.MethodsTwo dry human skulls were used to observe the bony nasion complex. Then, five colored silicon-injected human head specimens were dissected via TNCA for EMLP. Finally, the outcomes of patients who underwent TNCA were reviewed.ResultsThe nasion complex is an osseous complex that consists of the nasion and its adjacent structures, including the bilateral root of nasal bones, nasal process of frontal bones, anterior portion of the perpendicular plate of the ethmoid bone that connects with the inferior aspect of the nasal bones, and portions of the bilateral frontal process of the maxillary bones. Surgical landmarks for TNCA include the anterior superior portion of the nasal septum, anterior margin and axilla of the middle turbinate, frontal process of the maxilla bone, nasal process of the frontal bone and upper part of the nasal bone. These structures form a “mushroom sign” during cadaveric dissection and surgery. Twenty-one patients underwent TNCA, of whom 9 had tumors and 12 had chronic rhinosinusitis with nasal polyps (CRSwNP). None of them had major complications.ConclusionTNCA is expected to be a safe, and direct route for EMLP. Adequate understanding of the nasion complex and “mushroom sign” will be helpful to complete TNCA.

The Discrepancy in the Posterior Boundary of Necrotic Lesion Between Axial and Oblique Axial Slices of MRI in Patients with Osteonecrosis of the Femoral Head.

Little is known concerning differences in assessment of anteroposterior osteonecrotic lesion of the femoral head (ONFH) between the axial plane parallel to the body axis (axial) and the axial plane parallel to the femoral neck axis (oblique axial) using magnetic resonance imaging (MRI). This study aimed to compare the posterior boundary of necrotic lesions between the axial and oblique axial planes on MRI. This study retrospectively reviewed 120 consecutive hips in 71 patients (47 males and 24 females; mean age, 42 years) with ONFH, for which both axial and oblique axial MRI slices were available. The posterior boundaries of the necrotic lesions were calculated as the ratio of posterior intact circumference to anteroposterior circumference of the femoral head using mid-axial and mid-oblique axial MRI slices. The necrotic angles, calculated using the modified Kerboul method, were compared between cases with progression and nonprogression of collapse. The mean posterior intact ratio in the axial slice was 49.2% (range, 8.6 to 85.1%), while that in the oblique axial slice was 33.5% (7.5 to 79.2%). The posterior intact ratio in the oblique axial slice significantly decreased compared to that in the axial slice (p < 0.0001). In cases with progression of collapse, the mean necrotic angle was significantly larger in the oblique axial slice than in the axial slice (p < 0.0001). The sensitivity and specificity of the necrotic angle with regard to the prognosis of the femoral head were both higher when using the oblique axial slice (sensitivity: 88.4%, specificity: 82.3%) than when using the axial slice (sensitivity: 85.1%, specificity: 62.0%). The posterior intact ratio at a mean of 6.8 mm superior to the mid-axial slice corresponded to that of the mid-oblique axial slice. Our findings suggest that the posterior boundaries of necrotic lesions differ between axial and oblique axial slices, and examination of the oblique axial MRI slice might be more suitable for predicting the prognosis of the femoral head. Diagnostic-Investigating a diagnostic test. Level IV (Case series).