An evaluation of morphometry and dehiscence of facial canal: a systematic review and meta-analysis of observational studies.

INTRODUCTION: The facial canal (FC) is an extensive bony canal that houses the facial nerve and occupies a central position in the petrous part of temporal bone. It is of utmost significance to otologists due to its dehiscence and relationship to the inner or middle ear components. The main objectives of current investigation are to detect variations in the reported values ​​of FC anatomy that may occur due to different methodology and to elucidate the influence of age and ethnic factors on the morphological features of FC. METHODS: The methodology is adapted to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Pooled weighted estimation was performed to calculate the mean length, angle, and prevalence of dehiscence. RESULTS: The cross-sectional shape of FC varied from circular to ellipsoid index and is 1.45 [95% CI, 0.86-2.6]. The mean length of the FC is 34.42 mm [95% CI, 27.62-40.13 mm] and the mean width or diameter is 1.35 mm [95% CI, 1.013-1.63 mm]. The length of the FC in fetuses and children is 21.79 mm [95% CI, 18.44-25.15 mm], and 26.92 mm [95% CI, 23.3-28.3 mm], respectively. In meta-regression, age is observed as a predictor and accounts for 36% of the heterogeneity. The prevalence of FC dehiscence in healthy temporal bones is 29% [95% CI, 20-40%]. CONCLUSION: The different segments of the FC exhibit significant variability and an unusually high incidence of dehiscence, which could potentially have clinical implications for the etiopathogenesis of facial nerve dysfunction.

Variations of azygos vein: a cadaveric study with clinical relevance.

The azygos vein can be formed as a single root, two roots, and three roots, namely lateral, intermediate and the medial roots respectively. The hemiazygos vein and the accessory hemiazygos vein are the tributaries of azygos vein rather than its left side equivalents. Its variations, especially in young persons without any relevant risk factors, may result in thromboembolic illness. This study aimed to describe the morphological and morphometric variations of azygos system of veins. The present study was conducted on thirty formalin fixed adult human cadavers by dissecting azygos vein from formation to termination and variations were noted. The azygos vein was formed by a single root in 56.7%, by two roots: the lateral root and intermediate root in 36.7% cases and by the lateral root and medial root in 6.6%. The vertebral level of termination of azygos vein was seen at the level of T4 vertebrae in 70% cases, at the level of T3 vertebrae in 20% of cases and at the level of T5 vertebrae in 10% cases. The course of azygos vein was varying in 13.3%. These morphological variations can be useful while performing mediastinal surgery, mediastinoscopy, surgery of the deformations of the vertebral column, neurovascular surgeries of the retroperitoneal organs, disc herniation and fracture of thoracic vertebrae.

Analysing lumbar pedicle morphometry observed via traditional and recent modalities.

Objective: The present study was conducted to collect morphometric data on the lumbar vertebrae pedicles of the adult population from the eastern parts of India and analyse the variations, if any, with other parts of the country and the world. Methods: The retrospective cross-sectional study where lumbar pedicle morphometric data was obtained via dried bone, the 3D Lumbar vertebrae images were obtained by scanning the dried lumbar vertebrae, and the 3D lumbar vertebrae model was generated from a 1 mm thin CT scan slice of the Lumbar spine of patients who were advised to have a CT scan of the abdomen for reasons other than related to the vertebral column. Both linear and angular measurements in the lumbar pedicles were made bilaterally. Results: The transverse pedicle width is widest at L3 and the narrowest at L2 vertebra bilaterally. The sagittal pedicle width at L4 vertebrae was observed to be the widest bilaterally, while L3 had the narrowest pedicle. The pedicular and body length along the pedicular axis is longer than the central axis at all the lumbar levels. The linear measurement along the pedicular axis was longest at L5 bilaterally via both modes, with a range of 18.2-47.31 mm for bones and 21.03-49.28 mm for CT scan morphometry. The transverse pedicular angle on analysis was observed to increase as one goes down the spine from L1 to L5, with a steep rise between L4 and L5. In contrast, the sagittal pedicular angle decreased as we went caudally toward the L5 vertebrae. Conclusion: The present study data had significant differences among the values reported in the literature from the different populations for the parameters studied. The data obtained by this study will be highly beneficial for the success of the free-hand technique of pedicle screw insertion.

Moynihan's hump of the right hepatic artery in Calot's triangle: a systematic review and meta-analysis of its incidence and surgical importance.

INTRODUCTION: A rare variation known as "Moynihan's or caterpillar hump" of the right hepatic artery raises the danger of vascular and biliary injuries during hepatobiliary surgery. This research intends to carefully record every case (i.e., patients undergoing laparoscopic cholecystectomy or cadaver dissections) where the right hepatic artery received a caterpillar hump. METHODS: The literature search was conducted with the medical subject headings (MeSH) and EMTREE (subject headings unique to Embase) keywords. The keywords with Boolean operators (OR, AND, and NOT) were used to create search strings in all possible combinations to retrieve bibliographic data. Two authors independently performed a risk of bias assessment and data extraction. The random effects model was used to conduct a meta-analysis. RESULTS: Thirty studies with a total of 8418 subjects reported that Moynihan's hump was present in 3.81% of them, with a predictive interval of 0.88-16.45%. The incidence of the hump was 3.1% in surgical studies (7496 subjects) and 7.22% (95% CI 4.7-10.93%) in cadaveric data (625 cadavers). Only ten studies addressed the relationship between the caterpillar hump and the common bile duct. CONCLUSION: A patient with an unusually "small cystic artery" or "large right hepatic artery" is likely to have a "caterpillar hump". The caterpillar's hump of the right hepatic artery is subject to rare anatomical variations in its course that increase the risk of incorrect vessel ligation or injury during laparoscopic cholecystectomy.

An evaluation of mandibular canal variations: a systematic review and meta-analysis.

The inferior alveolar nerve and vessels are carried via the mandibular canal, which extends bilaterally from the inferior alveolar foramen to the mental foramen. Bifid and trifid mandibular canals result from abnormal fusions of nerve canals. The purpose of this study was to provide an up-to-date and comprehensive analysis of the prevalence of mandibular canal variations among healthy adults, and to identify any potential ethnic, sex, or laterality predilections. The prevalence of the bifid mandibular canal was 18.87% and that of the trifid canal 1.3%. Unilateral variants were three times commoner than bilateral. Each mandibular half had four canals emanating from separate openings on the lingual surface of the mandibular ramus. Retromolar and forward canals were the predominant subtypes, followed by dental; buccolingual were the least frequent. The mean length and diameter of the bifid mandibular canal were 13.62 mm and 1.63 mm, respectively. The possibility of a bifid mandibular canal is a crucial consideration in dental medicine. Because anatomical variations of the mandibular canal are fairly common, awareness of them is essential for anatomy teachers and for surgeons who operate in the oromaxillofacial region.

Prevalence and clinical relevance of the anatomical variations of suprarenal arteries: a review.

The suprarenal arteries are arising from three sources: superior suprarenal artery, middle suprarenal artery, and inferior suprarenal artery. Variations in the arterial supply of the suprarenal glands in respect to origin and number are quite common and very frequently reported. The most common variation noted is in the inferior suprarenal artery followed by the middle suprarenal artery and the least common variations were observed in the superior suprarenal artery. Arteriogram of the inferior suprarenal artery is crucial in suprarenal tumour diagnosis but variation in the branching pattern and multiplicity of these arteries can cause hindrance in arteriography. The absence of middle suprarenal artery was seen to be associated with increased number of the inferior suprarenal artery. Variation in the multiplicity of arteries was observed more frequently in the inferior suprarenal artery and middle suprarenal artery which was more on the right side in most of the studies. Also, the variation in suprarenal arteries was often correlated to variations in inferior phrenic and gonadal arteries. The variations were observed to be more common on the left side therefore right adrenalectomy should be preferred over the left one. The loop formed by the inferior suprarenal artery around the right renal vein can cause venous obstruction. These variations of suprarenal vasculature are explained on the developmental basis, and prior knowledge of such variants is crucial for nephrologists to ensure minimum blood loss while performing laparoscopic adrenalectomy especially for large adrenal tumours and pheochromocytoma where the duration of surgery exceeds the usual.

Raymond de Vieussens (1641-1715): connoisseur of cardiologic anatomy and pathological forms thereof.

Raymond de Vieussens was an exemplary anatomist who made seminal contributions in the field of cardiology. During initial part of his academic career, he adopted human dissection based experiments as medium of his research. This was in accordance with prevailing trend among anatomists during 17th century. He discovered the presence of tiny venous tributaries communicating between cardiac veins and chambers of heart (ducti carnosi/venae cordis minimae). He reported the existence of a collateral circulatory pathway between right and left coronary arterial systems (Vieussens arterial ring). He was the first to note the valve at the junction of great cardiac vein and coronary sinus (valve of Vieussens) and the prominent oval margin of the fossa ovalis (Vieussens Annulus). All his findings were associated with considerable clinical significance as evidenced in literature that followed. Vieussens accurately demonstrated the three-layered orientation of myocardium and gave a precise description of coronary arteries and their branches. At the onset of 18th century, buoyed by royal patronage from King Louis XIV of France, the second half of Vieussens illustrious career was defined by pathologic anatomy (autopsy based) and anatomo clinical correlations. This was a new trend initiated by Vieussens in anatomical research and was later adopted as a signature method by anatomists of 18th century. As a true connoisseur of cardiologic anatomy, Vieussens accurately charted the anatomo clinical correlations of cardiac tamponade, mitral stenosis and aortic regurgitation. His contributions were pivotal elements in metamorphosis of cardiology as a robust discipline of medicine in modern times.