The clinical anatomy of cystic artery variations: a review of over 9800 cases

PURPOSE

While laparoscopic cholecystectomy can be a routine procedure when biliary anatomy is normally located, cystic artery variations can easily disorientate the inexperienced surgeon to the anatomy of the hepatobiliary triangle. This study presents the clinically important anatomical variations of the cystic artery.

METHODS

PubMed, Medline, Cochrane Database of Systematic Reviews, and Google Scholar databases were searched to conduct a review of the existing English literature on the clinically important cystic artery variations. An aberrant vessel was defined as a vessel that originated from an atypical source and/or one that was present in a specimen in addition to the normal vessel.

RESULTS

The cystic artery originated typically from the right hepatic artery (79.02 %) and was found in the hepatobiliary triangle in only 5427 of 6661 (81.5 %) cases. Clinically important cystic artery variations are (1) the cystic artery located anterior to the common hepatic duct or common bile duct found in 485 of 2704 (17.9 %) and 228 of 4202 (5.4 %) of cases, respectively, (2) the cystic artery located inferior to the cystic duct found in 38 of 770 (4.9 %) of cases, (3) short cystic arteries found in 98 of 1037 (9.5 %) cases and (4) multiple cystic arteries found in (8.9 %) of cases.

CONCLUSION

These variations are common in the general population and can lead to inadvertent ligation of biliary ducts or aberrant vessels. Therefore, it is important for the hepatobiliary surgeon to be aware of these vascular anomalies to avoid operative complications.

Meta-analysis of vagus nerve stimulation treatment for epilepsy: correlation between device setting parameters and acute response

BACKGROUND

Vagus nerve stimulation (VNS) is an adjunctive neurophysiological treatment for those patients who have pharmacoresistant or surgically resistant partial onset epilepsy.

OBJECTIVE

The aim of this study is to determine the effects of high and low stimulation paradigms on a responder rate of ≥50 and ≥75% reduction in seizure frequency and associated adverse effects in adults and children.

METHOD

A literature search was performed using Medline, PubMed, EMBASE, and Cochrane library for studies using vagus nerve stimulation published from January 1980 until July 2014 for medically or surgically resistant partial onset seizures, in children and adults. No restrictions on languages were imposed.

DATA COLLECTION AND ANALYSIS

Four authors reviewed and selected studies for inclusion and exclusion. The search identified five randomized control trials that fit with our inclusion criteria. The following outcomes were evaluated: 50% or greater reduction in total seizure frequency, 75% or greater reduction in total seizure frequency, and adverse effects.

RESULTS

Four randomized controlled trials were analyzed in this meta-analysis. Results indicate high stimulation is more effective in adult patients who experienced ≥50 and ≥75% reduction in seizure frequency with a significant difference within both high and low stimulation groups. In children, there was no significant difference between the two groups and patients with ≥50 % reduction in seizures. Adverse effects such as hoarseness and dyspnea were more common in the high stimulation group where the remaining side effects were not statistically different among both groups.

CONCLUSION

High stimulation is more effective than low stimulation in producing a greater reduction in seizure frequency in patients with medically and surgically resistant epilepsy.

Macro/micro observational studies of fibres maintaining the biceps brachii tendon in the bicipital groove: application to surgery, pathology and kinesiology

BACKGROUND

There is controversy over the nature of tissues covering the bicipital groove protecting the biceps brachii tendon from dislocation/subluxation causing shoulder pain. Recent researches on cadaveric dissection and histological studies have changed the old concept of the transverse humeral ligament covering the bicipital groove to tendinous fibres of the subscapularis or interdigitating fibres of the subscapularis and supraspinatus. The change has not been incorporated into standard text books of anatomy. Therefore, the aim of the study is to support the new or old concept.

MATERIALS AND METHODS

Eighteen embalmed shoulders were dissected to determine the nature of the tissues over the bicipital groove. Tissues from 4 shoulders were processed and 16 histological slides were examined for fibre types. Theoretical analysis of ligament and tendon has also been carried out.

RESULTS

The dissection study revealed that the tissues over the bicipital groove were tendinous fibres of subscapularis/interdigitating fibres of the subscapularis and supraspinatus and fibrous expansions from the posterior lamina of the pectoralis major. This was supported by the histological slides which showed the signatures of collagen fibres with the characteristics of tendinous fibres.

CONCLUSIONS

No separate anatomical entity such as the transverse humeral ligament was detected in this study. Thus present study supports the view that the tissues covering the bicipital groove were formed by tendinous rather than ligamentous fibres.

Fat herniation through the canal of Schwalbe

The authors report a case of fat herniation through the canal of Schwalbe noted in a female cadaver during abdominopelvic dissection. Perineal hernias are rare hernias, and herniations through the hiatus of Schwalbe represent a rare posterior lateral perineal hernia. While these hernias are extremely rare, anatomists and surgeons should be aware of them, and the clinical significance and manifestations which may occur with these hernias.

A partially ossified falx cerebri

During a routine faculty prosection of the head and neck region of an adult female cadaver, a partial ossification of the falx cerebri was found. Ossification of other dural areas or regions of the body were not found. In addition, the brain and remaining organs appeared to be grossly normal. Reports of partial ossification of the falx cerebri are still rare and while certain pathologies such as nevoid basal cell carcinoma syndrome typically present with ossification of the falx on radiographs, the causal relationship of such an abnormality remains unclear.

Sex determination from partial segments and maximum femur lengths in Koreans using computed tomography

BACKGROUND

The aim of this study was to establish standards for determining sex from fragmentary and complete femurs in a Korean population.

MATERIALS AND METHODS

The statistical analysis of 12 variables (6 about breadth and 6 about length) based on 100 Korean femurs (from 50 males and 50 females) showed that all variables have significant sex differences.

RESULTS

The most accurate discriminant variable was the condylar breadth parallel with epicondylar breadth (87.6% accuracy). In contrast, the transverse shaft diameter was not a discriminant variable for sex determination (67.0% accuracy). Breadth-related variables were generally more accurate than length-related variables. Three variables (vertical diameter of the neck [VDN], medial epicondylarlength [MCL], and condylar breadth [CB]) were selected from stepwise analysis fordiscriminating sex (93.5% accuracy). The discriminating equation was as follows: 0.171 × VDN + 0.172 × MCL + 0.128 × CB2 - 21.471.

CONCLUSIONS

The results of this study are helpful for determining sex, even if a femur is found in a fragmented condition in the field.

Sonographic determination of normal Conus Medullaris level and ascent in early infancy

INTRODUCTION

Controversial reports exist in the literature regarding both the spinal level of the conus medullaris (CM) in normal infants and the age at which the CM achieves its adult level. Autopsy studies have demonstrated ascent continuing into early infancy while more recent imaging study series' suggest the adult conus level is attained by the 40th postmenstrual week.

METHODS

The authors conducted a retrospective review of 1,273 screening lumbar ultrasound studies performed over 5 years at a pediatric tertiary referral center. All patients were infants referred for initial imaging to rule out the presence of a tethered spinal cord. Referral sources included urban academic, urban private practice, and rural private practice pediatricians. After excluding studies lacking sufficient documentation (n = 90) and those reported as abnormal (n = 106), 1,077 remained for review. The CM level and patient age in days were recorded from each study. Statistical analysis was performed using unpaired t testing and ANOVA for continuous variables; chi-square for categorical data.

RESULTS

The mean CM level for infants in group I (ages 0-30 days) was compared to those in groups II (31-60 days) and group III (61-100 days). Group I had a mean CM level of 0.125 and 0.2 vertebral segments lower than groups II and III (p = 0.0005 and <0.0001, respectively). ANOVA comparison of all three groups confirmed a rostral migratory trend (p < 0.001). The prevalence of CM level caudal to L2 in group I was 13 %, group II 11.4 %, and group III 4.7 %; also indicating a significant rostral trend (p = 0.004).

CONCLUSIONS

Rostral migration of CM level continues through the first few months of post-natal life, albeit of limited extent. Documentation of continued ascent in a neonate may obviate the need for magnetic resonance imaging.

The ventricular system of the brain: a comprehensive review of its history, anatomy, histology, embryology, and surgical considerations

INTRODUCTION

The cerebral ventricles have been recognized since ancient medical history. Their true function started to be realized more than a thousand years later. Their anatomy and function are extremely important in the neurosurgical panorama.

METHODS

The literature was searched for articles and textbooks of different topics related to the history, anatomy, physiology, histology, embryology and surgical considerations of the brain ventricles.

CONCLUSION

Herein, we summarize the literature about the cerebral ventricular system.

Proboscis lateralis

INTRODUCTION

Proboscis lateralis is a rare congenitally acquired facial abnormality characterized by a soft-tissue tube- or trunk-like appendage projecting from the surface of the face, most frequently rooted in the medial canthal region. Proboscis lateralis is generally associated with a wide range of concomitant craniofacial anomalies, giving rise to multiple theories describing the embryological pathogenesis and various classification systems to account for the pathological associations.

RESULTS/CONCLUSION

This paper provides a literature review of the rare manifestations of proboscis lateralis and represents a summary of current literature related to embryological pathogenesis, definitive diagnosis, and surgical management approaches.

Anatomical features and clinical relevance of a persistent trigeminal artery

Background:

Although persistent trigeminal artery (PTA) is uncommonly identified, knowledge of this structure is essential for clinicians who interpret cranial imaging, perform invasive studies of the cerebral vasculature, and operate this region.

Methods:

A review of the medical literature using standard search engines was performed to locate articles regarding the PTA, with special attention with anatomical descriptions.

Results:

Although anatomical reports of PTA anatomy are very scarce, those were analyzed to describe in detail the current knowledge about its anatomical relationships and variants. Additionally, the embryology, classification, clinical implications, and imaging modalities of this vessel are extensively discussed.

Conclusions:

Through a comprehensive review of isolated reports of the PTA, the clinician can better understand and treat patients with such an anatomical derailment.

A review of the tragal pointer: anatomy and its importance as a landmark in surgical procedures

The tragal pointer has long been used as a surgical landmark for the identification of the facial nerve trunk and the maxillary artery in such procedures as parotidectomy, internal fixation of subcondylar and condylar fractures, mandibular osteotomy, temporomandibular joint arthroplasty, and percutaneous blocks of branches of the trigeminal nerve and pterygopalatine ganglion. Aside from its use as an external landmark, it has also been implicated as a contributor to crease formation in the presence of peripheral arterial disease. This article will review the available literature on the tragal pointer's use as an external landmark.

Interactive Effects of Planting Date and Cultivar on Tomato Spotted Wilt of Peanut

Field experiments were conducted at Gainesville and Marianna, FL in 2004 and 2005 in which severity of spotted wilt, caused by Tomato spotted wilt virus, and pod yield were compared in six peanut (Arachis hypogaea) cultivars. The six cultivars included the moderately field resistant cultivars ANorden, C-99R, and Georgia Green; the highly field resistant cultivars AP-3 and DP-1; and the susceptible cultivar SunOleic 97R. There were four trials at each location, with four planting dates that ranged from late March to early June. Tomato spotted wilt severity in moderately resistant and susceptible cultivars was lower at Gainesville than at Marianna in both years in moderately resistant and susceptible cultivars. Trends in incidence for the two locations were less evident for AP-3 and DP-1. At Gainesville, there were few differences in tomato spotted wilt severity, and severity ratings were similar for Georgia Green and SunOleic 97R in two of four trials in 2004 and across all trials in 2005. At Marianna, severity ratings were lower for Georgia Green than for SunOleic 97R in six of the eight trials, and severity of tomato spotted wilt was lower for AP-3, C-99R, and DP-1 than for Georgia Green in all eight trials. In 2004, there was a trend toward decreasing severity ratings for Georgia Green and SunOleic 97R with later planting dates, but not for AP-3 or DP-1 at Marianna. Split-plot field experiments were also conducted at Tifton, GA in 2005 through 2007 in which incidence of tomato spotted wilt and pod yield were compared for peanut cultivars AP-3 and Georgia Green across planting dates ranging from late April through late May. Incidence of tomato spotted wilt was lower for AP-3 than for Georgia Green within each planting date of all years, and planting date effects were smaller in AP-3, if observed at all, than in Georgia Green. In most planting dates of all three trials, yields were higher for AP-3 than for Georgia Green. The relationships between yield and planting date were not consistent. These results indicate that the level of field resistance in AP-3 and DP-1 cultivars is sufficient to allow planting in late April without greatly increasing the risk of losses to tomato spotted wilt.

A review of the T2 segment of the brachial plexus

Although the complex architecture of the brachial plexus (BP) has been described for decades, recent literature still aims to elucidate the variation in nerve root contributions to the BP. Understanding this variability in the nerve morphology of the BP may assist physicians and surgeons in the diagnosis and management of certain clinical conditions that involve the BP, either directly or indirectly due to its close association with neighbouring structures. In this article, we review the current anatomical knowledge of the BP, focusing especially on its T2 contribution, and discuss the causes and consequences of some relevant BP pathologies.

Can Doppler ultrasonographic indices of the renal artery predict the presence of supernumerary renal arteries?

BACKGROUND

Variations of the renal arteries, including the presence of supernumerary renal arteries, are important to be identified prior to renal transplant. Angiography has been the gold standard test for the pretransplant evaluation of the renal vasculature. However, this modality is expensive and invasive. The aim of this study was to assess whether Doppler ultrasonographic (DU) indices of the renal artery could predict the presence of supernumerary renal arteries.

METHODS AND MATERIALS

Retrospectively, we analyzed multidetector computed tomography angiography (presence or absence of the supernumerary renal artery), DU (peak systolic velocity, resistive index, pulsatility index, end-diastolic velocity, and acceleration time) findings of 30 healthy potential renal transplant donors. Recipient operator characteristic (ROC) curves were used to examine the predictive values of the available DU indices for supernumerary renal arteries.

RESULTS

The mean age of donors was 28.4 +/- 4.1 years. Of 60 kidneys evaluated, a supernumerary renal artery was found in 10%. The ROC curve analysis revealed an area under the curve of noninformative (below 0.5) for all DU parameters, indicating that none of the studied parameters could predict the presence of a supernumerary renal artery.

CONCLUSIONS

Although the smaller diameter of the main renal artery has previously been found to predict the presence of supernumerary renal arteries, the present study revealed that DU indices of the renal artery may not indicate the presence of supernumerary renal arteries.

An interrupted inferior vena cava in a situs inversus. Case report and review of the literature

Situs inversus with interrupted inferior vena cava is an uncommon anatomic variant found in the abdominal and thoracic viscera. In this report, we present a 59-year-old woman with this variation, found during gross anatomical dissection. While this type of variation has been variable, in the present case the hepatic veins drained directly into a very short (2.2 cm) inferior vena cava. The infrarenal component of the inferior vena cava was present and drained into the azygos and hemiazygos veins. Clinical considerations of this variant anatomy are of interest, as they may present in patients as pathology on cross sectional imaging.

Neurological presentation and long-term outcome following operative intervention in patients with meningocele manqué

We review and describe the neurological presentation and long-term outcome of patients with meningocele manqué, and describe the dysraphic features associated with this entity. Our series of patients was collected over a 25-year period with a mean follow-up of 11.5 years. The mean age of presentation was 10.4 years and 72% of the patients presented with an abnormal neurological examination. At most recent follow-up, symptoms were stable, improved, and progressed in 47, 37 and 16%, respectively. Meningocele manqué was associated with focal hirsutism in 37% of the cases. These bands were primarily found in the lumbar spine and involved two sequential vertebral levels in 42% of cases. Sectioning of meningocele manqué has good long-term results in the majority of patients. These bands should be sought in the evaluation of patients with spinal dysraphism and surgically transected.

Variation of the axillary arch muscle with multiple insertions

Axillary arch muscles have been described as having variable and sometimes multiple insertions. We report a 90-year-old female cadaver with an axillary arch muscle that originated from the latissimus dorsi and was inserted into the pectoralis major, pectoralis minor and coracoid process. Recognising that axillary arch muscles can be present in such complex forms is important in clinical practice.

Screening for renal artery stenosis in patients with aorticoiliac occlusive disease

BACKGROUND

The prevalence of atherosclerotic renal artery disease has increased with improved life expectancy. Because renal artery stenosis is a potentially correctable cause of hypertension and ischemic nephropathy, early identification of this entity may lead to proper hypertension control and improved renal function and survival. The aim of this study was to determine the prevalence and patterns of subclinical renal artery stenosis in patients with aorticoiliac atherosclerosis.

PATIENTS AND METHODS

The abdominal angiographies of 44 patients with high-grade aorticoiliac occlusive disease (> 70% stenosis) were reviewed for evidence of renal artery stenosis. This was compared to a group of 20 patients with mild-to-moderate aorticoiliac disease (< 70% stenosis). These patients had no history of renal artery disease or renal failure.

RESULTS

In patients with high-grade aorticoiliac occlusive disease, renal artery stenosis was found in 25 patients (56.8%); 13 with unilateral (29.5%) and 12 (27.3%) with bilateral involvement. A hemodynamically significant stenosis (> 50%) was found in 11 patients (25%), one of whom had bilateral stenosis (2.3%). High-grade renal artery stenosis (> 70%) or complete arterial occlusion was noted on seven sides (7.9%). The most common sites of stenosis were the origin and first centimeter of the renal artery. In patients with mild-to-moderate aorticoiliac disease, renal artery stenosis was found in two patients (10%).

CONCLUSIONS

The present study revealed that subclinical renal artery disease may be present in more than half of the patients with high-grade aorticoiliac atherosclerosis highlighting the need for proper risk stratifications and screening programs. Based on our results, we suggest that examination of the renal arteries in these patients may be necessary in order to delay or prevent complications. Additionally, such information may have important therapeutic implications in planning reconstructive vascular surgeries or percutaneous angioplasties.

Levator claviculae: a case report and review of the literature

The levator claviculae is an uncommon anatomical variant found in the posterior cervical triangle. In this report we present a 78-year-old man with this muscular variation, which was found during gross anatomical dissection. While sites of insertion and origin have been variable, in the present case the muscle originated from the left transverse processes of C3 and C4, and inserted onto the lateral third of the ipsilateral clavicle. Clinical considerations of this variant anatomy are of interest, as they may present in patients as a supraclavicular mass and may also mimic pathology on cross-sectional imaging.

Morphologic variation of the diaphragmatic crura: a correlation with pathologic processes of the esophageal hiatus?

The contributions of muscle fibers from the right and left diaphragmatic crura to the formation of the esophageal hiatus have been documented in several studies, none coming to a complete consensus on the number of anatomic variations or the prevalence of these variations in the human population. These variations may play a role in the pathogenicity of specific diseases that involve the esophageal hiatus, such as hiatal hernias. We examined a total of two hundred adult cadavers during 2000-2007. The variations in the diaphragmatic crura, particularly their muscular contributions to the formation of the esophageal hiatus, were grossly examined and revealed a bilateral occurrence of diaphragmatic crura in all 200 specimens. The results of the various morphological patterns of circumferential muscle fibers forming the esophageal hiatus were classified into six groups. The most common type (Type I, 45%) formed the esophageal hiatus from muscular contributions arising solely from the right crus. In Type II (20%) the esophageal hiatus was formed by muscular contributions from the right and left crura. In Type III (15%), the right and left muscular contributions arose from the right crus with an additional band from the left crus. Type IV (10%) showed that the right and left muscular contributions arose from the right crus, with two additional (anterior and posterior) bands arising from the left crus. Type V (5%) demonstrated the contributions arising solely from the left crus. In Type VI (5%) the right and left contributions originated from the left crus with two additional bands, one from the right crus and one from the left crus. These variations may play a role in the pathogenicity of specific diseases that involve the esophageal hiatus such as hiatal hernia, gastroesophageal reflux disease and Dunbar's syndrome.

An abnormal variation of the brachial plexus with potential clinical significance

In this case of a male adult Caucasian cadaver, variations were noted involving the location of the CS ventral ramus descending anterior and superolateral to the anterior scalene muscle. An unusual communicating branch was discovered that originated from C5 at the midpoint of the anterior scalene muscle, two centimeters proximal to Erb's point, to communicate with C6 and another communicating branch originating from C6 to C7. Awareness of the possibility of this variation is of great importance during certain surgical procedures. Comparison of this case with the literature is discussed.

A case of May-Thurner syndrome

May-Thurner syndrome is a condition that results from narrowing of the left common iliac vein lumen due to pressure from the right common iliac artery as it crosses anterior to it. We describe a very rare case in which a previously asymptomatic patient presented with May-Thurner syndrome.

A review of the distribution of the arterial and venous vasculature of the diaphragm and its clinical relevance

The diaphragm is the major respiratory muscle of the body. As it plays such a vital role, a continuous arterial and venous blood supply is of the utmost importance. It is therefore not surprising to find described in the literature a complex system of anastomoses that contributes to the maintenance of this muscle's life-preserving contraction. Understanding the anatomy of the diaphragm and any divergence in its vasculature is literally vital to humanity. In the light of this, we review the literature on the blood supply to the diaphragm, with specific emphasis on the recent description of the inferior phrenic vessels and the superior phrenic artery, summarize the clinical significance of the diaphragmatic vasculature and suggest future avenues of study to further expand on this current body of knowledge.

Intraluminal septation of the basilar artery: incidence and potential clinical significance

Variations in the cerebrovascular tree can increase surgical or interventional morbidity. To date, only scant comments are to be found in the literature regarding intraluminal variations of the basilar artery. To further elucidate such anatomy, a cadaveric study was performed. One hundred and fifty human brains were evaluated for the present study. The basilar artery was identified in each and sectioned longitudinally to observe for the presence of intraluminal septa. One specimen (0.67%) was identified that harbored an intraluminal septum of the basilar artery. This wall was within the proximal basilar artery and measured 3 mm by 1.5 mm. No specimen was found to have other anomalies of the basilar artery and in the single specimen with an intraluminal septum no signs of intracranial pathology were seen. Although seemingly rare, septation of the basilar artery can be found. Knowledge of such an intraluminal vascular variation may be important during invasive and minimally invasive procedures.

The ansa subclavia: a review of the literature

The ansa subclavia, subclavian loop, Vieussens' ansa or Vieussens' loop is a nerve cord that connects the middle cervical and inferior cervical sympathetic ganglia, forming a loop around the subclavian artery. The structure of the ansa subclavia is evolutionarily conserved from rats, guinea pigs, the porcine species and dogs to humans. A common application in physiological studies is to electrically stimulate the ansa subclavia in animal models as a robust protocol to modulate stimulatory cardiac sympathetic input. Despite a large number of physiological studies utilizing the ansa subclavia, only very brief descriptions have been devoted to it in standard anatomy texts. An extensive search found only one report in the English language literature concerning the anatomy of the ansa subclavia. The aim of this report, therefore, was to provide a comprehensive review of the clinical anatomy of the ansa subclavia and to discuss its potential physiological functions.