Revisiting the anatomy of the left ventricle in the light of knowledge of its development.

Despite centuries of investigation, certain aspects of left ventricular anatomy remain either controversial or uncertain. We make no claims to have resolved these issues, but our review, based on our current knowledge of development, hopefully identifies the issues requiring further investigation. When first formed, the left ventricle had only inlet and apical components. With the expansion of the atrioventricular canal, the developing ventricle cedes part of its inlet to the right ventricle whilst retaining the larger parts of the cushions dividing the atrioventricular canal. Further remodelling of the interventricular communication provides the ventricle with its outlet, with the aortic root being transferred to the left ventricle along with the newly formed myocardium supporting its leaflets. The definitive ventricle possesses inlet, apical and outlet parts. The inlet component is guarded by the mitral valve, with its leaflets, in the normal heart, supported by papillary muscles located infero-septally and supero-laterally. There is but a solitary zone of apposition between the leaflets, which we suggest are best described as being aortic and mural. The trabeculated component extends beyond the inlet to the apex and is confluent with the outlet part, which supports the aortic root. The leaflets of the aortic valve are supported in semilunar fashion within the root, with the ventricular cavity extending to the sinutubular junction. The myocardial-arterial junction, however, stops well short of the sinutubular junction, with myocardium found only at the bases of the sinuses, giving rise to the coronary arteries. We argue that the relationships between the various components should now be described using attitudinally appropriate terms rather than describing them as if the heart is removed from the body and positioned on its apex.

Topographical distribution and prevalence of basal duct-like recess sign in a cohort of Papillary Craniopharyngioma-novel findings and implications.

PURPOSE: Basal duct-like recess (DR) sign serves as a specific marker of papillary craniopharyngiomas (PCPs) of the strictly third-ventricular (3 V) topography. Origins of this sign are poorly understood with limited validation in external cohorts. METHODS: In this retrospective study, MRIs of pathologically proven PCPs were reviewed and evaluated for tumor topography, DR sign prevalence, and morphological subtypes. RESULTS: Twenty-three cases with 24 MRIs satisfied our inclusion criteria. Median age was 44.5 years with a predominant male distribution (M/F ratio 4.7:1). Overall, strictly 3 V was the commonest tumor topography (8/24, 33.3%), and tumors were most commonly solid-cystic (10/24, 41.7%). The prevalence of DR sign was 21.7% (5/23 cases), all with strictly 3 V topography and with a predominantly solid consistency. The sensitivity, specificity and positive and negative predictive value of the DR sign for strict 3 V topography was 62.5%, 100%, 100% and 84.2% respectively. New pertinent findings associated with the DR sign were observed in our cohort. This included development of the cleft-like variant of DR sign after a 9-year follow-up initially absent at baseline imaging. Additionally, cystic dilatation of the basal tumor cleft at the pituitary stalk-tumor junction and presence of a vascular structure overlapping the DR sign were noted. Relevant mechanisms, hypotheses, and implications were explored. CONCLUSION: We confirm the DR sign as a highly specific marker of the strictly 3 V topography in PCPs. While embryological and molecular factors remain pertinent in understanding origins of the DR sign, non-embryological mechanisms may play a role in development of the cleft-like variant.

A natural experiment to assess recess frequency on children's physical activity in Arizona (U.S.) elementary schools.

BACKGROUND: In the United States, the number of state policies mandating recess in schools has rapidly increased over the past decade; however, few policies specify recess frequency. Informed by an ecological model of physical activity (PA) policy, this study examined and compared total amounts and intensity of PA expended during recess among children attending schools in compliance with Arizona recess policy ARS§ 15-118 mandating 2 + daily recess periods versus not. METHODS: PA during recess was measured among grade three children (ages 8-10) in four randomly selected elementary schools (two complying averaging 30 daily recess minutes; two non-complying averaging 15 daily recess minutes) in Maricopa County, Arizona. Group-level PA was assessed by direct observation using the System for Observing Play and Leisure (137 observations). A subset of students (N = 134) from all schools wore ActiGraph GT3X + devices during recess to measure individual PA. General linear mixed effects models were used to analyze the impact of recess frequency on group and individual PA during recess. RESULTS: Students attending complying schools spent significantly greater proportions of time in moderate-to-vigorous PA (MVPA) based on direct observation (5%) and accelerometry (15%) and less time being sedentary based on accelerometry (14%) during recess. Across the school day, this would equate to 5.1 more MVPA minutes based on systematic direct observation and 9.5 more MVPA minutes based on accelerometry, and 4.1 less minutes being sedentary based on accelerometry if students received two daily 15-minute recess periods compared to one. CONCLUSIONS: Students attending elementary schools implementing 2 + recesses, in accordance with state policy, demonstrated greater MVPA and less sedentary time, providing preliminary evidence that recess frequency is associated with greater PA intensity among children during recess. Schools that adhere to state-level PA policies may provide a more supportive environment for PA, resulting in increased movement among students. Specifying recess frequency should be considered in statewide recess policy.

Advancing Lung Ultrasound: The Development and Application of the Anatomical M-Mode Evaluation for Lung Swings (AMLES) Technique in Respiratory Assessment.

Exploring the frontiers of lung ultrasound, this document details a groundbreaking technique for lung function evaluation using anatomical M-mode, also known as angle-independent M-mode. The method, termed AMLES (Anatomical M-Mode Evaluation for Lung Swings), quantifies the displacement of the lung curtain observed at the bilateral costophrenic recesses. This approach translates lung curtain movements into graphical data, offering insights into respiratory mechanics and enhancing the assessment of lung ventilation in emergency settings.

Endoscopic precaruncular medial transorbital and endonasal multiport approaches to the contralateral skull base: a clinicoanatomical study.

OBJECTIVE: Minimally invasive endoscopic endonasal multiport approaches create additional visualization angles to treat skull base pathologies. The sublabial contralateral transmaxillary (CTM) approach and superior eyelid lateral transorbital approach, frequently used nowadays, have been referred to as the "third port" when used alongside the endoscopic endonasal approach (EEA). The endoscopic precaruncular contralateral medial transorbital (cMTO) corridor, on the other hand, is an underrecognized but unique port that has been used to repair CSF rhinorrhea originating from the lateral sphenoid sinus recess. However, no anatomical feasibility studies or clinical experience exists to assess its benefits and demonstrate its potential role in multiport endoscopic access to the other contralateral skull base areas. In this study, the authors explored the application and potential utility of multiport EEA combined with the endoscopic cMTO approach (EEA/cMTO) to three target areas of the contralateral skull base: lateral recess of sphenoid sinus (LRSS), petrous apex (PA) and petroclival region, and retrocarotid clinoidocavernous space (CCS). METHODS: Ten cadaveric specimens (20 sides) were dissected bilaterally under stereotactic navigation guidance to access contralateral LRSS via EEA/cMTO. The PA and petroclival region and retrocarotid CCS were exposed via EEA alone, EEA/cMTO, and EEA combined with the sublabial CTM approach (EEA/CTM). Qualitative and quantitative assessments, including working distance and visualization angle to the PA, were recorded. Clinical application of EEA/cMTO is demonstrated in a lateral sphenoid sinus CSF leak repair. RESULTS: During the qualitative assessment, multiport EEA/cMTO provides superior visualization from a high vantage point and better instrument maneuverability than multiport EEA/CTM for the PA and retrocarotid CCS, while maintaining a similar lateral trajectory. The cMTO approach has significantly shorter working distances to all three target areas compared with the CTM approach and EEA. The mean distances to the LRSS, PA, and retrocarotid CCS were 50.69 ± 4.28 mm (p < 0.05), 67.11 ± 5.05 mm (p < 0.001), and 50.32 ± 3.6 mm (p < 0.001), respectively. The mean visualization angles to the PA obtained by multiport EEA/cMTO and EEA/CTM were 28.4° ± 3.27° and 24.42° ± 5.02° (p < 0.005), respectively. CONCLUSIONS: Multiport EEA/cMTO to the contralateral LRSS offers the advantage of preserving the pterygopalatine fossa contents and the vidian nerve, which are frequently sacrificed during a transpterygoid approach. This approach also offers superior visualization and better instrument maneuverability compared with EEA/CTM for targeting the petroclival region and retrocarotid CCS.

Anteriorly Tilted Coronal CT of Paranasal Sinuses for Endoscopic Sinus Surgery.

Conventional coronal CT scans of paranasal sinuses, aligned perpendicularly to the nasal floor, often deviate significantly from the endoscopic view during sinus surgery. This discrepancy complicates the interpretation of anatomical structures. In response, we propose the utilization of anteriorly tilted coronal CT slices to enhance anatomical understanding. These slices align more closely with the endoscopic view, fostering an intuitive grasp of paranasal sinus anatomy. This study aims to quantify the tilt of the endoscope to the nasal floor during endoscopic sinus surgery. To figure out the tilt of the endoscopically true coronal slices, we calculated the tilt of the endoscope to the nasal floor in the operative setting by taking pictures of the operation and measuring the image and sagittal CT. Fourteen patients (25 sides of paranasal sinuses) were analyzed. Endoscope tilts to the nasal floor were measured at different anatomical landmarks: 16.2 ± 9.7 degrees (lower edge of ground lamella), 29.8 ± 7.9 degrees (central ground lamella), 62.3 ± 10.1 degrees (most superior part), and 25.6 ± 7.0 degrees (optic canal). In conclusion, we showed the actual tilt of the endoscope to the nasal floor during endoscopic sinus surgery. A 30-degree anteriorly tilted coronal scan for frontal recess and sphenoid sinus is more intuitive than a traditional coronal scan, which helps surgeons understand the complex sinus anatomy.

Endoscopic transnasal prelacrimal recess approach via the orbital floor to the infraorbital region: an anatomical study.

PURPOSE: The aim of this study is to describe the maximum exposure of the infraorbital region via the orbital floor using the transnasal prelacrimal recess approach (PLRA), and to provide an anatomical basis for treating lesions in the infraorbital region. METHODS: Ten freshly injected frozen heads were dissected using the PLRA. The orbital floor was removed along the border of the medial infraorbital quadrangle, and the periorbita was opened to expose the infraorbital region. The areas of the medial infraorbital quadrangles were measured and analyzed. The PLRA was applied separately on the left and right sides of each cadaver head, resulting in a total of 20 prelacrimal recess approaches. RESULTS: The PLRA enabled visualization of the optic nerve and the central retinal artery through the orbital floor. By integrating both medial and lateral approaches in relation to the inferior rectus muscle, all crucial anatomical structures within the infraorbital region could be clearly identified. The area of the medial infraorbital quadrangle was 420.65 ± 24.03 mm2. CONCLUSION: The PLRA provides access through the orbital floor to the maximum boundary of the infraorbital region, including the lateral orbital wall at the outermost level, the superior rectus muscle at the topmost level, and the medial orbital wall at the innermost level.

Prelacrimal recess approach for maxillary sinus inverted papilloma: a 15-year experience from a single center.

PURPOSE: This large retrospective, single-center, follow-up study investigated the endoscopic prelacrimal recess approach (PLRA) for treating maxillary sinus inverted papilloma (MSIP). METHODS: Between January 2007 and November 2022, patients with MSIP treated with PLRA were enrolled. Data on clinical manifestations, imaging, and surgical procedures were collected. The visual analog scale (VAS) scores for maxillofacial numbness and nasal symptoms and the SNOT-22 nasal symptom scores were statistically analyzed. RESULT: Of 122 patients (68 males and 54 females) enrolled in the study, with a mean age of 50.75 ± 12.84 years (26-80 years), 111 patients underwent PLRA, nine underwent modified PLRA, one converted to an endoscopic medial maxillectomy (EMM), and one to an endoscopic modified Denker's approach. The average follow-up was 86.60 (13-192) months, the recurrence rate was 3.28%, and 29 patients (23.77%) complained of maxillofacial numbness one month postoperatively, which disappeared in most cases one year after surgery. Five patients (4.10%) experienced mild numbness at the end of the follow-up period. Maxillary sinus ostium contracture or atresia occurred in two cases (1.64%). After surgery, the VAS nasal symptom scores improved significantly (P < 0.001). SNOT-22 indicated that the most common postoperative symptom was thick nasal discharge. CONCLUSION: PLRA is a flexible first-choice surgical treatment for maxillary sinus inverted papilloma and can be modified according to the extent of the lesion, the surgeon's experience and technique, and surgical instruments. That can help achieve complete resection and reduce recurrence and surgical complications. Upper teeth numbness, the most common postoperative complication, tends to disappear after 1 year.

Prelacrimal Recess Approach in Unilateral Maxillary Sinus Lesions: What Is the Impact and Efficacy?

Background and Objectives: Chronic sinusitis is a commonly encountered diagnosis for otorhinolaryngologists. The profound negative effect of rhinosinusitis on patients' quality of life is frequently overlooked, and surgical lines of treatment are numerous. The aim of the study was to assess the comparative efficacy of endoscopic middle meatal antrostomy with the endoscopic prelacrimal recess approach, combined with middle meatal antrostomy in the treatment of unilateral chronic maxillary sinus lesion. Materials and Methods: Thirty patients with unilateral chronic maxillary sinus lesions enrolled in the study at Alahsa hospital. Patients were divided into two groups: 15 treated through a middle meatal antrostomy and 15 treated via a combined middle meatal antrostomy and prelacrimal recess approach. Demographic and clinical information of the patients, including the medical history, CT scan findings, diagnosis, recurrence, and complications, were gathered and analyzed. Pre- and postoperative clinical findings were graded utilizing the Lund-Kennedy Endoscopic Scoring System. Results: The enrolled patients varied in age from 18 to 56, with 60% being male and 40% being female. Antrochoanal polyp, maxillary sinus mucocele, and unilateral allergic fungal sinusitis were among the pathological diagnoses. The follow-up period averaged 14.3 months. Following surgery, two patients in Group II encountered nasal discomfort, which included synechia and epiphora. The success rate for preserving a patient's disease-free condition was 86.7%. A statistically significant difference in disease-free incidence was observed among the patients in group II. In group I, recurrence was identified in 26.7% of the patients. The postoperative symptoms diminished considerably, and the VAS score was reduced substantially. In Group II patients, however, there was no significant difference in scarring. Clinically significant differences were observed in the mean total Lund-Kennedy Endoscopic scores when compared to their preoperative values. Conclusions: Achieving endoscopic access to the sinus's anterior, lateral, inferior, and inferomedial regions is facilitated by operating via the prelacrimal recess, which is the most advantageous approach. This approach facilitates rapid mucosal healing by maintaining the integrity of the nasolacrimal duct and mucosal covering. The specific pathology, surgical objectives, surgeon expertise, and equipment accessibility influence the choice of endoscopic surgical technique.

Enhancing contrast distribution with the far lateral approach in lumbar transforaminal epidural steroid injections: A retrospective analysis.

BACKGROUND: Herniated intervertebral disc (HIVD) with radiculopathy is a common degenerative spine disorder. Transforaminal epidural steroid injection (TFESI) is one of the pain relief treatments for lumbar radiculopathy recommended by evidence-based guidelines. Adequate contrast distribution is correlated with better pain control, but the best approach has not been confirmed yet. AIM: To confirm the distribution of contrast medium injected with a new approach of TFESI, that is, far lateral lateral recess approach (FLLR-TFESI). METHODS: Patients receiving TFESI due to HIVD with radiculopathy between 2010 January and 2020 August were retrospectively enrolled. While the FLLR-TFESI was taken as the experimental group, the conventional approach was viewed as the control group. The baseline characteristics, the pattern of contrast enhancement under fluoroscopic guidance, and the complications of these patients were collected and analyzed. RESULTS: A total of 380 patients were analyzed (143 in control group and 237 in experimental group). The two groups were balanced in most baseline characteristics, except disc extrusion (p = 0.01) and scoliosis (p = 0.04). The FLLR-TFESI have a better contrast distribution (p < 0.01), even after adjustment (p < 0.001). No intrathecal injection was noted, but higher rate of intra-disc injection was noted in FLLR-TFESI group (10% vs. 3%, p = 0.008). CONCLUSION: The FLLR-TFESI has a superior contrast enhancement and distribution in comparison to conventional approach. Prospective study to confirm the study result as well as the clinical benefits is suggested in the future.

Physical activity and social interaction assessments in schoolyard settings using the System for Observing Outdoor Play Environments in Neighborhood Schools (SOOPEN).

BACKGROUND: The schoolyard environment provides key opportunities to promote physical activity and socioemotional development for children. Schoolyards can also serve as a community park resource outside of school hours. We aimed to: (i) implement and evaluate reliability of the System for Observing Outdoor Play Environments in Neighborhood Schools (SOOPEN), (ii) assess schoolyard use by children during recess and community members of all ages outside of school hours, and (iii) investigate relationships of schoolyard and children´s group characteristics with physical activity levels and prosocial interactions. METHODS: In this cross-sectional study, we observed student and community visitor behavior using SOOPEN at three urban elementary schoolyards in Tacoma, Washington, USA, prior to renovations intended to expand each facility's use as a community park in neighborhoods with poor park access. We assessed interrater reliability using intraclass correlation coefficients and described current levels of schoolyard use (at the group level), physical activity, and prosocial behavior. Physical activity was assessed on a five-point scale and dichotomized to indicate moderate-to-vigorous physical activity (MVPA). Social interactions were coded as prosocial, antisocial, or neutral. We examined associations of selected schoolyard features and group characteristics with group MVPA and prosocial behavior during recess using modified Poisson regression to estimate prevalence ratios (PR) and 95% confidence intervals (CI). RESULTS: We observed a total of 981 activity-defined, informal groups in the schoolyards, and achieved good to excellent interrater reliability using SOOPEN. Community use of the schoolyards during evenings and weekends was limited (n = 56 groups). During 26, 25-50 min recess periods (n = 833 groups), 19% of groups were engaged in MVPA. Schoolyard areas with paved surfaces were associated with more MVPA (PR = 1.52, 95% CI: 1.04, 2.23) compared to field/grass areas; supervised groups were associated with less MVPA than groups not directly supervised by an adult (PR = 0.59, 95% CI: 0.36, 0.96). Schoolyard characteristics were not associated with prosocial behavior. Mixed-gender groups were associated with more MVPA and more prosocial behavior. CONCLUSIONS: Our study using SOOPEN, a reliable new activity observation tool, highlights the multi-dimensional dynamics of physical activity and social interactions in schoolyards, which could be leveraged to promote healthy behaviors during and outside of school hours.

Pain improvement and reoperation rate after full-endoscopic decompression for lateral recess stenosis: a 10-year follow-up.

PURPOSE: To share long-term clinical outcomes and our experience with full-endoscopic interlaminar decompression (FEI) for lateral recess stenosis (LRS). METHODS: We included all patients who underwent FEI for LRS from 2009 to 2013. VAS for leg pain, ODI, neurological findings, radiographic findings, and complications were analyzed at one week, one month, three months, and one year postoperation. The telephone interview for local patients with simple questions was done approximately ten years after the operation. International patients receive an email with the same questionnaire as local patients during the same follow-up period. RESULTS: One hundred and twenty-nine patients underwent FEI for LRS with complete data during 2009-2013. Most of the patients (70.54%) had LRS radiculopathy for less than one year, mainly L4-5 (89.92%), followed by L5-S1 (17.83%). Early outcomes three months after surgery showed that most patients (93.02%) reported significant pain relief, and 70.54% reported no pain at their ODI scores were significantly reduced from 34.35 to 20.32% (p = 0.0052). In contrast, the mean VAS for leg pain decreased substantially by 3.77 points (p < 0.0001). There were no severe complications. At ten years of follow-up, 62 patients responded to the phone call or email. 69.35% of the patients reported having little or no back or leg pain, did not receive any further lumbar surgery, and were still satisfied with the result of the surgery. There were six patients (8.06%) who underwent reoperation. CONCLUSION: FEI for LRS was satisfactory at 93.02%, with a low complication rate during the early follow-up period. Its effect seems to decline slightly in the long term at a 10-year follow-up. 8.06% of the patients subsequently underwent reoperation.

Optimal insertion positions of anterior-posterior orientation sacroiliac screw.

PURPOSE: To explore the optimal insertion positions of anterior-posterior orientation sacroiliac screw (AP-SIS). METHODS: Pelvic CT data of 80 healthy adults were employed to measure the anatomical parameters including the insertable ranges of S1 and S2, the length, width and height of the channel with three different horizontal and vertical anterior insertion points starting from the ilium-acetabular recess. To compare pelvic stability by replicating a type C Tile lesions, fifteen synthetic pelvises were fixed with an anterior plate and a posterior AP-SIS employing different anterior insertion points, the whole specimen displacements and shifts in the sacroiliac gap under a cyclic vertical load of 300 N in a biomechanical machine recorded. RESULTS: The posterior and anterior insertable ranges averaged 17.9 × 8.5mm2 and 47.1 × 21.2 mm2, respectively. The channel lengths for three horizontal anterior insertion points gradually decreased from front to back with significant difference (p < 0.05), whereas the width and height for three horizontal anterior insertion points and the parameters for the three vertical anterior insertion points were similar (p > 0.05). The displacements and shifts for three horizontal insertion points gradually increased from front to back (p < 0.05) whereas the measurements involving the three vertical insertion points were similar (p > 0.05). CONCLUSION: The posterior insertable range is small, where the center between adjacent nerve roots (foramens) is the optimal posterior insertion point. The anterior insertable range is large, where the iliac-acetabular recess is the optimal anterior insertion point for S1 and S2, providing the longest channel and best stability.

How I do it: the biportal endoscopic inclined-ipsilateral technique to decompress the lumbar lateral recess.

BACKGROUND: Various full-endoscopic techniques have been developed to reach the lateral recess of the lumbar spine. However, specialized surgical tools, including expensive spinal endoscopic systems, and a steeper learning curve to mastering the technique are required. METHOD: We present a novel target-addressed unilateral biportal endoscopic technique to reach directly the lumbar lateral recess, particularly useful at L4-L5 and L5-S1. The technique follows an inclined-ipsilateral trajectory to preserve the lateral extension of ligamentum flavum and the facet joint as much as possible. CONCLUSION: This technique was associated with all the advantages of minimally invasive decompressive procedures and outstanding outcomes.

How I do it? Endoscopic endonasal transpterygoid repair of sphenoid lateral recess cerebrospinal fluid leak after previous unsuccessful transcranial surgery.

BACKGROUND: Direct access to the sphenoid lateral recess offers the best chance of sealing spontaneous cerebrospinal fluid (CSF) rhinorrhea caused by lateral sphenoid encephaloceles of the Sternberg canal defect. METHOD: We present a case of spontaneous left-sided sphenoid lateral recess CSF leak after previous unsuccessful transcranial surgery managed with an endoscopic endonasal transpterygoid approach (EETA). An anatomical-based step-by-step illustration of the EETA was presented in the surgical video. CONCLUSION: This case demonstrates the value of endoscopic endonasal transpterygoid corridor in the exposure and manipulation of the sphenoid lateral recess.

Endoscopic endonasal access to the lateral recess of the sphenoid sinus.

BACKGROUND: The standard endoscopic endonasal approach gives access to the median sphenoid sinus, but not to its lateral part. We propose an endoscopic technique for lesions in the lateral sphenoid sinus. METHOD: Based on our experience with 28 patients, we have developed a less invasive approach to the lateral recess of the sphenoid sinus, limiting the opening of the maxillary sinus while avoiding resection of the inferior turbinate and ethmoidal cells. The technique is described. CONCLUSION: The proposed endoscopic approach is reliable and safe to treat CSF leak or tumours located within the lateral recess of the sphenoid sinus.

Utility of flexible interventional endoscopy in endoscopic sinus surgery: a case series.

PURPOSE: During endoscopic sinus surgery (ESS), difficult-to-reach pathologies need an extended endoscopic approach or an external approach. We started to use a flexible interventional endoscope (FIE) to evaluate the necessity of those approaches. The study's objective is to describe our experience and define patients who could benefit from this technique. METHODS: We reviewed every patient who benefited from FIE associated with ESS at our tertiary University Hospital between January 2021 and February 2022. RESULTS: During this period, we did 107 ESS, and 14 patients benefited from the FIE, representing 13% of our ESS. The median duration of the flexible endoscopy time was 14 min (4-38 min). We identified three groups of patients who can benefit from the FIE. The first one is for patients with a fungal infection, to control and to clean lateral recesses in a noninvasive manner. The second one is for patients with a pathology of the lateral frontal sinus, to remove the frontoethmoidal cells or mucocele with the biopsy forceps through the working channel. The third group is for patients with inverted papillomas, to precisely identify the insertion and to decide on the most appropriate surgical approach. CONCLUSIONS: In selected cases, using flexible endoscopy during ESS helps decide the optimal surgical approach and sometimes treat the pathology through a limited approach. Prospective studies for each group of patients are needed to confirm the benefit of this new combined procedure.

Effect of anterior maxillary wall shape on ease of prelacrimal recess approach among Asians and Westerners.

PURPOSE: Endoscopic sinus surgery has been widely used in the treatment of most maxillary diseases, although the inability to access lesions in the anterior and inferior maxillary sinus walls is a major disadvantage. In few cases, the prelacrimal recess (PLR) approach can be used, which secures an overall view within the maxillary sinus. The distance between the anterior maxillary wall and lacrimal duct is related to the ease of the PLR approach. First we measured the distance between the anterior maxillary wall and lacrimal duct using anatomical image analysis to classify the types and then evaluated whether anatomical factors were related to the results. METHODS: Both sides of the sinuses were evaluated in 272 participants (544 sides). After marking a tangent line (line 1 [L1]) through the posterior surface of the anterior maxillary sinus wall and a parallel line (line 2 [L2]) to the anterior surface of the lacrimal duct, the vertical distance between L1 and L2 was measured. Vertical distances of < 3 mm, 3-7 mm, and > 7 mm were classified as PLR approach types I, II, and III, respectively. In the axial plane image, line 3 (L3) (a horizontal line starting from the inner anterior maxillary sinus wall) was drawn and the angle with L1 (L1-L3A) was measured. RESULTS: The proportions of types I, II, and III were 23.2% (126), 55.0% (299), and 21.8% (119), respectively. The mean L1-L3As for types I, II, and III were 12.87 ± 4.92°, 11.20 ± 5.08°, and 10.40 ± 4.47°, respectively, showing a significant difference in mean values (p < 0.001). The L1-L3A and vertical distance between L1 and L2 showed a significant negative correlation (r = - 0.201, p < 0.001). CONCLUSIONS: We observed a correlation between the distance from the anterior maxillary wall to the lacrimal duct and L1-L3A. The L1-L3A indicates the degree of curvature of the anterior maxillary wall; therefore, the smaller the L1-L3A, the easier it may be to access the PLR.

Anterior ethmoid and frontal sinus drainage pathways: five patterns formed and defined by their bony walls.

PURPOSE: To perform endoscopic sinus surgery safely and effectively, surgeons need to visualize the complex anatomy of the anterior ethmoid and frontal sinus region. Because this anatomy is so variable and individualized, the foundation of understanding lies in identifying, following, and visualizing the drainage pathway patterns and anticipating possible variations. METHODS: We studied 100 sides (50 cases: 22 male, 28 female, aged 12-86, average age 46.5 years, ± 19.5) using computed tomography (CT) and multiplanar reconstruction (MPR) to identify and classify the drainage pathways leading to the frontal sinus and anterior ethmoidal cells. RESULTS: Analysis revealed five patterns of drainage pathways defined by their bony walls: between the uncinate process and the lamina papyracea [UP-LP]; between the uncinate process and the middle turbinate [UP-MT]; between the uncinate process and the accessory uncinate process [UP-UPa]; between the uncinate process and the basal lamella of the ethmoidal bulla [UP-BLEB]; and between the basal lamella of the ethmoidal bulla and the basal lamella of the middle turbinate [BLEB-BLMT]. In most cases, BLEB formed the posterior wall of the drainage pathway of the frontal sinus, indicating BLEB could be one of the most important landmarks for approaching the frontal sinus. CONCLUSIONS: As endoscopic sinus surgery depends on an understanding of this anatomy, this study may help surgeons to identify and follow the drainage pathways more accurately and safely through the anterior ethmoid to the frontal sinus.

Correlation between Pneumatization Variants of Paranasal Sinuses and Skull Base and Spontaneous Cerebrospinal Fluid Rhinorrhea: A Case-Control Study.

INTRODUCTION: Spontaneous cerebrospinal fluid rhinorrhea (SCSFR) is the most common type of cerebrospinal fluid leakage and may cause serious cerebral complications. The aim of this research was to investigate the relationship between the degree of pneumatization variants of the paranasal sinus and skull base and the incidence of SCSFR. METHODS: In total, 131 patients with SCSFR were analyzed, and 50 patients suffering from the nasal septal deviation were selected as controls. The pneumatization of the paranasal sinus and skull base was observed by CT scan. RESULTS: Among the 137 fistulas, 55 (40.15%) were found in the ethmoid sinus. The incidences of Onodi cells (27.27 vs. 8%) and type 3 lateral recess of the sphenoid sinus (LRSS, 70.37 vs. 22%) in the SCSFR subgroups were significantly higher than those in the control group (p < 0.05). Moreover, the occurrence of SCSFR was linearly correlated with the classification of Onodi cells and LRSS (p < 0.05). There was no significant difference in the incidence of frontal cells, anterior clinoid process pneumatization, and posterior clinoid process pneumatization between the SCSFR patients and the controls. CONCLUSION: The most common site of SCSFR is the ethmoid sinus. The excessive pneumatization of the Onodi cell and LRSS increases the risk for the occurrence of SCSFR in the ethmoid sinus and sphenoid sinus, respectively. The possible association between the paranasal sinus ontogeny and SCSFR pathophysiology needs further studies.