Marios Loukas

The pediatric Chiari I malformation: a review

BackgroundBoth the diagnosis and treatment regimens for the Chiari I malformation (CIM) are varied and controversial. The present paper analyzes the literature regarding this form of hindbrain herniation in regard to definition, anatomy, pathobiology, symptoms, findings, treatment, and outcomes.DiscussionsAppropriate literature germane to the CIM is reviewed and discussed. There is variation in the reported anatomy, outcome, and treatment for children with CIM. Based on the literature, most patients have preoperative symptoms or findings (e.g., syringomyelia) improve no matter what surgical technique is utilized. However, standardized treatment paradigms based on randomized controlled studies are still necessary to elucidate the optimal selection and treatment criteria.

The relationship of myocardial bridges to coronary artery dominance in the adult human heart

Myocardial bridging is recognized as an anatomical variation of the human coronary circulation in which an epicardial artery lies in the myocardium for part of its course. Thus, the vessel is ‘bridged’ by myocardium. The anterior interventricular branch of the left coronary artery has been reported as the most common site of myocardial bridges but other locations have been reported. The purpose of this study was to provide more definitive information on the vessels with myocardial bridges, the length and depth of the bridged segment, and the relationship between the presence of bridges and coronary dominance. Two hundred formalin‐fixed human hearts were examined. Myocardial bridges were found in 69 (34.5%) of the hearts with a total of 81 bridges. One bridge was found in 59 of these hearts and multiple bridges were observed in ten (eight with double bridges and two with triple bridges). Bridges were most often found over the anterior interventricular artery (35 hearts). Bridges were also found over the diagonal branch of the left coronary artery (14), over the left marginal branch (five) and over the inferior interventricular branch of the left coronary artery (six). Bridges were also found over the right coronary artery (15 hearts), over the right marginal branch (four) and over the inferior interventricular branch of the right coronary artery (two). The presence of bridges appeared to be related to coronary dominance, especially in the left coronary circulation. Forty‐six (66.6%) of the hearts with bridges were left dominant. Forty‐two of these had bridges over the left coronary circulation and four over the right coronary circulation. Seventeen hearts (24.6%) were right dominant. Eleven of these had bridges over the right coronary circulation and six over the left coronary circulation. The remaining six hearts were co‐dominant with four having bridges over the left coronary circulation and two over the right coronary circulation. The mean length of the bridges was 31 mm and the mean depth was 12 mm. The possible clinical implications of myocardial bridging may vary from protection against atherosclerosis to systolic vessel compression and resultant myocardial ischaemia.

A detailed observation of variations of the facial artery, with emphasis on the superior labial artery

The reconstruction of lip defects through the use of the Abbė flap and other lip flap procedures involves surgical manipulation of one of the major branches of the facial artery, specifically the superior labial artery (SLA). We examined 284 hemifaces derived from 142 formalin fixed cadavers. Observations regarding the distribution patterns of the facial artery were recognized and categorized into five Types, labeled “A” through “E”.Type A (135, 47.5%): facial artery bifurcates into SLA and lateral nasal (the latter gives off inferior and superior alar and ends as angular); Type B (110, 38.7%): similar to Type A, except lateral nasal terminates as superior alar (angular artery is absent); Type C (24, 8.4%): facial artery terminates as SLA; Type D (11, 3.8%): angular artery arises directly from facial arterial trunk rather than as the termination of lateral nasal, with the facial artery ending as superior alar; Type E (4, 1.4%): facial artery terminates as a rudimentary twig without providing any significant branches. Furthermore, we were able to categorize variations within each Type. Sub-Type variations were examined in Types A through C (A: 1–7; B: 1–4; C: 1–3). Our aim was to equip both the anatomist and surgeon with a more thorough understanding of the vasculature of the face, as well as to enable plastic surgeons to have a more confident approach to reconstructive procedures in this region.

Anatomical and surgical considerations of the sacrotuberous ligament and its relevance in pudendal nerve entrapment syndrome

In view of the paucity of literature, this study was undertaken to reappraise the gross anatomy of the sacrotuberous ligament (STL), with the objective of providing an accurate anatomical basis for clinical conditions involving the STL. We studied the gross anatomy of the STL in 50 formalin fixed cadavers (100 sides) during the period of 2004–2005. All specimens exhibited an STL with a ligamentous part and (87%) of specimens exhibited a membranous (falciform) segment, which extended towards the ischioanal fossa. The variations of the falciform extensions were classified into three types. In Type I (69%), the falciform process extended towards and along the ischial ramus to terminate at the obturator fascia. In Type II (108%), the falciform process extended along the ischial ramus, fused with the obturator fascia and continued towards the ischioanal fossa. In addition, the medial border of the falciform process descended to fuse with the anococcygeal ligament, forming a continuous membrane. Lastly, in Type III (13%), the falciform process of the STL was absent. The above mentioned data could have an important implication to the understanding of the relationship between the pudendal nerve and the sacrotuberous ligament and their relevance to pudendal nerve entrapment syndrome.

The clinical anatomy of the triangle of Petit

IntroductionHernias through the triangle of Petit (TP) are uncommon. The anatomy of the TP is known to be variable, yet quantitative data are scant.Materials and methodsThe triangle was observed in 80 adult cadavers and its dimensions and surface area were measured.ResultsOn the basis of surface area we classified the triangles into four types. Type I or small TP, with a surface area of <8xa0cm2, accounted for 43.7% of our specimens. Type II (26.2%) were intermediate in size, with a surface areas of 8–12xa0cm2. Type III (12.5%) were large triangles with surface areas >12xa0cm2. Finally, Type IV (17.5%) were not triangles. In these, the latissimus dorsi was covered by the external abdominal oblique muscle.ConclusionsWe hope these data will help prediction of which patients are at greater risk of herniation through the TP.

An anatomical classification of the variations of the inferior phrenic vein

The majority of anatomical textbooks of gross anatomy offer very little information concerning the anatomy and distribution of the inferior phrenic vein (IPV). However, in the last decade, an increasing number of reports have arisen, with reference to the endoscopic embolization of esophageal and paraesophageal varices, as well as venous drainage of hepatocellular carcinomas (HCC). The IPV is one of the major sources of collateral venous drainage in portal hypertension and HCC. The aim of this study was to identify the origin and distribution of the IPVs (right and left), both in normal and (selective) pathological cases. We have examined 300 formalin-fixed adult cadavers, without any visible gastrointestinal disease, and 30 cadavers derived from patients with HCC. The right IPV drained into the following: the inferior vena cava (IVC) inferior to the diaphragm in 90%, the right hepatic vein in 8%, and the IVC superior to the diaphragm in 2%. The left IPV drained into the following: the IVC inferior to the diaphragm in 37%, the left suprarenal vein in 25%, the left renal vein in 15%, the left hepatic vein in 14%, and both the IVC and the left adrenal vein in 1% of the specimens. The IPVs possessed four notable tributaries: anterior, esophageal, lateral and medial. The right IPV served as one of the major extrahepatic draining veins for all 30 cases of HCC. These findings could have potential clinical implications in the transcatheter embolization of esophageal and paraesophageal varices, as well as in mobilizing the supradiaphragmatic segment of IVC.

Regional anatomic structures of the elbow that may potentially compress the ulnar nerve

HYPOTHESISnTraumatic injuries to the ulnar nerve at the elbow are a frequent problem as it is vulnerable to stretching and compression with motion of the upper limb. The aim of the present study was to explore the course of the ulnar nerve at the elbow and forearm and to determine possible anatomical structures that may cause compression of this structure.nnnMATERIALS AND METHODSnWe examined 12 upper limbs from cadavers. The length of any fibrous bands, and if present, their distance to the medial epicondyle was recorded.nnnRESULTSnOn 5 sides a fibrous band originating from the medial intermuscular septum was observed to cross over the ulnar nerve. The average length of the fibrous band was 5.7 cm, and it attached to the medial epicondyle. The mean length of the ulnar nerve as it coursed in the cubital tunnel was 3.8 cm. In 4 of the cases, the ulnar nerve was covered by muscle fibers originating from the flexor digitorum superficialis and extending to the flexor carpi ulnaris. On 5 sides we observed fibrous thickenings, and on 8 sides vascular structures were found crossing over the ulnar nerve.nnnDISCUSSIONnThe cubital tunnel is the most common site of compression of the ulnar nerve. Numerous surgical procedures are recommended for cubital tunnel syndrome. Simple decompression is used most commonly. Although surgical procedures are reported to provide efficient pain relief and functional recovery, residual or recurrent symptoms have been reported. Reasons for such recurrences may be more proximal or distal compression of the ulnar nerve as seen in our study.nnnCONCLUSIONnKnowledge of possible compression sites of the ulnar nerve is important to the surgeon so that complications are avoided and postoperative recurrence is decreased.nnnLEVEL OF EVIDENCEnBasic science study.

Anatomy and potential clinical significance of the vastoadductor membrane

Few reports are found in the extant medical literature regarding the vastoadductor membrane. This membrane effectively creates a subcompartment within the subsartorial canal. The lower limbs of 16 embalmed adult cadavers were dissected to identify the vastoadductor membrane and note its measurements. A vastoadductor membrane was identified in all specimens and was derived from the medial intermuscular septum. This membrane connected the medial edge of the vastus medialis muscle to the lateral edge of the adductor magnus muscle. Membranes were all wider proximally and narrowed distally. The mean length of this structure was 7.6xa0cm. The mean width of the vastoadductor membrane at its proximal, midportion, and distal parts was 2.2, 1.7, and 0.5xa0cm, respectively. The mean distance from the anterior superior iliac spine to the proximal border of the vastoadductor membrane was 28xa0cm. The mean distance from the distal border of the membrane to the adductor tubercle was 10xa0cm. Seventy-five percent of specimens exhibited a fenestrated vastoadductor membrane. Branches of the saphenous nerve to the skin of the medial thigh pierced the vastoadductor membrane in 31% of specimens. Two specimens demonstrated branches derived from the branch of the obturator nerve that pierced this membrane en route to the skin of the medial thigh. Perforating venous branches from the great saphenous vein were identified in 22% of specimens. As compression of the femoral artery at the adductor hiatus is a well-recognized entity, the clinician may also try to explore potential compression of this vessel more proximally by an overlying vastoadductor membrane. The authors would also hypothesize that due to the interconnection between the adductor magnus and vastus medialis by the vastoadductor membrane that a potential synergy exists between the functions of these two muscles.

The clinical anatomy of the crista terminalis, pectinate muscles and the teniae sagittalis.

The crista terminalis (CT) is an important anatomic landmark due its close association with the sinoatrial node artery and the origin of the pectinate muscles (PM). However, the gross anatomy of the PM in relation to the CT has not been well described. The aim of our study has been to investigate the location and the morphology of PM in relation to the CT. We examined 300 adult formalin-fixed human hearts. All PM originated from the CT and extended along the wall of the appendage toward the vestibule of the tricuspid valve. It was observed that the PM varied significantly with respect to arrangement and course of its fibers. We were able to classify the course of the PM, including the most prominent PM called the tenia sagittalis (TS), into 6 different patterns with 3 different TS types. In Type A (15%), the TS was absent. Type B (65%) demonstrated a single TS and Type C (20%) was characterized by the presence of multiple TS. Furthermore, the course of the PM was classified into 6 patterns: Type I (40%), the PM was oriented perpendicular to the CT with uniform spacing and lack of crossover (trabeculation); Type II (20%), non-uniform PM was organized in a haphazard, trabecular fashion with numerous crossovers; Type III (15%), the PM had uniform spacing with no trabeculation with fibers oriented parallel to the CT; Type IV (10%), had arborizing PM originating from a common muscular trunk (solitary trunk); Type V (10%), fibers were oriented both perpendicular and parallel to the CT, similar in architecture to Type III, but with more than one common muscular trunk; Type VI (5%), prominent muscular column with velamentous PM with potential implications in cardiac catheterization procedures. The exact morphology of PM and TS may be clinically important in right atrial catheterization procedures, as well as in the development of arrhythmias but further investigations are now necessary to prove this theory.

Relationships of the sural nerve with the calcaneal tendon: an anatomical study with surgical and clinical implications

The percutaneous repair of the calcaneal tendon (CT) places the sural nerve (SN) at high risk for injury up to 60%. The aim of our study, therefore, was to explore and describe the course of SN in relation to the CT and to provide an anatomical description of the area in which the SN resides in order to assist surgeons in avoiding iatrogenic injury during surgical procedures in the leg. Forty-four lower extremities of 22 adult cadavers were dissected and the course of the sural nerve investigated. The CT was divided into ten horizontal equal fractions. The widths of CT, and horizontal distances of the SN and small saphenous vein (SSV) to a vertical line connecting the midpoints of these fractions were measured. All the measurements were obtained using a computer-assisted image analysis system. In 95.5% of the specimens the sural nerve was medial to the lateral border of the CT proximally and was intersecting with the lateral border of the CT at the 55% of the mid-tendon line. The SN divided into its terminal branches at a mean of 90% of the mid-tendon line. Based on our results, the course of the sural nerve is quite variable and seems to have the highest risk of injury at its proximal portion. The sutures placed on the CT distal to the 55% of the mid-tendon line may decrease iatrogenic nerve injury.