Przemysław A. Pękala

The prevalence and anatomical characteristics of the accessory head of the flexor pollicis longus muscle: a meta-analysis

Background and Objectives. The accessory head of the flexor pollicis longus muscle (AHFPL), also known as the Gantzer’s muscle, was first described in 1813. The prevalence rates of an AHFPL significantly vary between studies, and no consensus has been reached on the numerous variations reported in its origin, innervation, and relationships to the Anterior Interosseous Nerve (AIN) and the Median Nerve (MN). The aim of our study was to determine the true prevalence of AHFPL and to study its associated anatomical characteristics. Methods. A search of the major electronic databases PubMed, EMBASE, Scopus, ScienceDirect, and Web of Science was performed to identify all articles reporting data on the prevalence of AHPFL in the population. No date or language restriction was set. Additionally, an extensive search of the references of all relevant articles was performed. Data on the prevalence of the AHFPL in upper limbs and its anatomical characteristics and relationships including origin, insertion, innervation, and position was extracted and pooled into a meta-analysis using MetaXL version 2.0. Results. A total of 24 cadaveric studies (n = 2,358 upper limb) were included in the meta-analysis. The pooled prevalence of an AHFPL was 44.2% (95% CI [0.347–0.540]). An AHFPL was found more commonly in men than in women (41.1% vs. 24.1%), and was slightly more prevalent on the right side than on the left side (52.8% vs. 45.2%). The most common origin of the AHFPL was from the medial epicondyle of the humerus with a pooled prevalence of 43.6% (95% CI [0.166–0.521]). In most cases, the AHFPL inserted into the flexor pollicis longus muscle (94.6%, 95% CI [0.731–1.0]) and was innervated by the AIN (97.3%, 95% CI [0.924–0.993]). Conclusion. The AHFPL should be considered as more a part of normal anatomy than an anatomical variant. The variability in its anatomical characteristics, and its potential to cause compression of the AIN and MN, must be taken into account by physicians to avoid iatrogenic injury during decompression procedures and to aid in the diagnosis and treatment of Anterior Interosseous Nerve Syndrome.

The origin of the medial circumflex femoral artery: a meta-analysis and proposal of a new classification system

Background and Objectives. The medial circumflex femoral artery (MCFA) is a common branch of the deep femoral artery (DFA) responsible for supplying the femoral head and the greater trochanteric fossa. The prevalence rates of MCFA origin, its branching patterns and its distance to the mid-inguinal point (MIP) vary significantly throughout the literature. The aim of this study was to determine the true prevalence of these characteristics and to study their associated anatomical and clinical relevance. Methods. A search of the major electronic databases Pubmed, EMBASE, Scopus, ScienceDirect, Web of Science, SciELO, BIOSIS, and CNKI was performed to identify all articles reporting data on the origin of the MCFA, its branching patterns and its distance to the MIP. No data or language restriction was set. Additionally, an extensive search of the references of all relevant articles was performed. All data on origin, branching and distance to MIP was extracted and pooled into a meta-analysis using MetaXL v2.0. Results. A total of 38 (36 cadaveric and 2 imaging) studies (n = 4,351 lower limbs) were included into the meta-analysis. The pooled prevalence of the MCFA originating from the DFA was 64.6% (95% CI [58.0–71.5]), while the pooled prevalence of the MCFA originating from the CFA was 32.2% (95% CI [25.9–39.1]). The CFA-derived MCFA was found to originate as a single branch in 81.1% (95% CI [70.1–91.7]) of cases with a mean pooled distance of 50.14 mm (95% CI [42.50–57.78]) from the MIP. Conclusion. The MCFA’s variability must be taken into account by surgeons, especially during orthopedic interventions in the region of the hip to prevent iatrogenic injury to the circulation of the femoral head. Based on our analysis, we present a new proposed classification system for origin of the MCFA.

Consensus guidelines for the uniform reporting of study ethics in anatomical research within the framework of the anatomical quality assurance (AQUA) checklist: Framework of the AQUA Checklist

Unambiguous reporting of a studys compliance with ethical guidelines in anatomical research is imperative. As such, clear, universal, and uniform reporting guidelines for study ethics are essential. In 2016, the International Evidence‐Based Anatomy Working group in collaboration with international partners established reporting guidelines for anatomical studies, the Anatomical Quality Assurance (AQUA) Checklist. In this elaboration of the AQUA Checklist, consensus guidelines for reporting study ethics in anatomical studies are provided with in the framework of the AQUA Checklist. The new guidelines are aimed to be applicable to research across the spectrum of the anatomical sciences, including studies on both living and deceased donors. The authors hope the established guidelines will improve ethical compliance and reporting in anatomical research. Clin. Anat. 31:521–524, 2018.

Risk of iatrogenic injury to the infrapatellar branch of the saphenous nerve during hamstring tendon harvesting: A meta‐analysis

Our goal was to conduct a comprehensive analysis of studies reporting data on the rate of injury to the infrapatellar branch of the saphenous nerve following hamstring tendon graft harvesting with respect to the type of incision over the pes anserinus.

Variations in the Arterial Blood Supply to the Penis and the Accessory Pudendal Artery: A Meta-Analysis and Review of Implications in Radical Prostatectomy

Purpose: The aim of this meta‐analysis was to analyze the available literature and provide comprehensive data on the prevalence and variations of the accessory pudendal artery and the 3 types of penile blood supply, including type 1—internal pudendal artery only, type 2—internal pudendal artery and accessory pudendal artery, and type 3—accessory pudendal artery only. Materials and Methods: We performed an extensive search of the major databases and identified 23 studies in a total of 4,945 patients suitable for inclusion in this meta‐analysis. Studies eligible for inclusion included cadaveric, imaging or intraoperative studies. Extracted data were pooled into a meta‐analysis with a random effects model using MetaXL, version 5.0 (EpiGear International, Sunrise Beach, Queensland, Australia). The chi‐square test and Higgins I2 statistics were used to assess heterogeneity among included studies. Results: Our findings revealed that the most common type was type 1 with a pooled prevalence estimate of 61.9%, followed by types 2 and 3 with a pooled prevalence estimate of 32.8% and 5.4%, respectively. In our analysis of the accessory pudendal artery the vessel was present in 28.5% of patients. When present, unilateral accessory pudendal arteries were most common (pooled prevalence estimate 72.5%) or they were present on the right or the left side (pooled prevalence estimate 48.0% or 52.0%, respectively). They most commonly originated from the obturator artery and the inferior vesical artery (pooled prevalence estimate 48.9% and 29.6%, respectively). The most common type was apical accessory pudendal arteries (pooled prevalence estimate 60.9%). Conclusions: A penile blood supply originating at least in part from an accessory pudendal artery represents more than a third of cases. Based on the anatomical findings when an accessory pudendal artery is present, we advocate attempted preservation of the vessel during radical prostatectomy to best maintain the penile arterial blood supply, especially in patients with type 3 or in older patients with type 2.

Prevalence of foramen arcuale and its clinical significance: a meta-analysis of 55,985 subjects

OBJECTIVE The foramen arcuale (FA) is a bony bridge located over the vertebral artery on the posterior arch of the atlas. The presence of an FA can pose a risk during neurosurgery by providing a false impression of a broader posterior arch. The aim of this study was to provide the most comprehensive investigation on the prevalence of the FA and its clinically important anatomical features. METHODS Major electronic databases were searched to identify all studies that reported relevant data on the FA and the data were pooled into a meta-analysis. RESULTS A total of 127 studies (involving 55,985 subjects) were included. The overall pooled prevalence of a complete FA was 9.1% (95% CI 8.2%-10.1%) versus an incomplete FA, which was 13.6% (95% CI 11.2%-16.2%). The complete FA was found to be most prevalent in North Americans (11.3%) and Europeans (11.2%), and least prevalent among Asians (7.5%). In males (10.4%) the complete FA was more common than in females (7.3%) but an incomplete FA was more commonly seen in females (18.5%) than in males (16.7%). In the presence of a complete FA, a contralateral FA (complete or incomplete) was found in 53.1% of cases. CONCLUSIONS Surgeons should consider the risk for the presence of an FA prior to procedures on the atlas in each patient according to sex and ethnic group. We suggest preoperative screening with computerized tomography as the gold standard for detecting the presence of an FA.

The Variable Emergence of the Infrapatellar Branch of the Saphenous Nerve

Abstract The infrapatellar branch of the saphenous nerve (IPBSN) is a cutaneous nerve of the lower limb, which arises distal to the adductor canal. High variability in the emergence, course, branching, termination, and morphometrics of the IPBSN poses an increased risk of injury to the nerve during surgical interventions on the anteromedial aspect of the knee. The aim of this study was to describe the anatomical characteristics of the IPBSN. This study utilized cadaveric (n = 100) and ultrasonography (n = 30) assessments, and meta‐analysis. In the cadaveric study, the presence of IPBSN and its emergence mode in relation to the sartorius muscle (SaM) was determined (type A‐anterior; type B‐posterior; type C‐penetrating the SaM). Ultrasonography examinations were conducted on healthy volunteers to determine the presence and mode of the emergence of the nerve. Finally, from electronic databases searching, all studies reporting the IPBSN emergence data were pooled into a meta‐analysis. The mean distance between the medial border of the patellar ligament (MBPL) and the IPBSN at the level of the patellar apex (PA) was also analyzed in the cadaveric, ultrasonography, and meta‐analysis portions of the study. Six studies (n = 336 limbs), including the present cadaveric study, were pooled into the meta‐analysis of emergence. The most prevalent IPBSN emergence mode was type C (42.9%) followed by type B (41.9%) and type A (15.4%). In the ultrasonography assessment, type A was found to be the most common (82.8%). The mean distance between the MBPL and the IPBSN at the level of the PA was 4.89 ± 0.22 cm, and 5.57 ± 0.91 cm, for the cadaveric and meta‐analysis studies combined, and the ultrasonography assessment, respectively. This multimodality study shows that the most common type of IPBSN emergence is type C. The horizontal distance between the MBPL and the IPBSN at the level of the PA is usually between 4.5 and 5.6 cm. Understanding the anatomy of IPBSN emergence is crucial for orthopedic surgeons to minimize the risks of iatrogenic nerve injury during surgical procedures in the region.

Surgical anatomy of the sciatic nerve: A meta‐analysis

The sciatic nerve has varying anatomy with respect to the piriformis muscle. Understanding this variant anatomy is vital to avoiding iatrogenic nerve injuries. A comprehensive electronic database search was performed to identify articles reporting the prevalence of anatomical variations or morphometric data of the sciatic nerve. The data found was extracted and pooled into a meta‐analysis. A total of 45 studies (n = 7068 lower limbs) were included in the meta‐analysis on the sciatic nerve variations with respect to the piriformis muscle. The normal Type A variation, where the sciatic nerve exits the pelvis as a single entity below the piriformis muscle, was most common with a pooled prevalence of 85.2% (95%CI: 78.4–87.0). This was followed by Type B with a pooled prevalence of 9.8% (95%CI: 6.5–13.2), where the sciatic nerve bifurcated in the pelvis with the exiting common peroneal nerve piercing, and the tibial nerve coursing below the piriformis muscle. In morphometric analysis, we found that the pooled mean width of the sciatic nerve at the lower margin of the piriformis muscle was 15.55 mm. The pooled mean distance of sciatic nerve bifurcation from the popliteal fossa was 65.43 mm. The sciatic nerve deviates from its normal course of pelvic exit in almost 15% of cases. As such we recommend that a thorough assessment of sciatic nerve variants needs to be considered when performing procedures in the pelvic and gluteal regions in order to reduce the risk of iatrogenic injury.

The new frontier of studying human anatomy: Introducing evidence‐based anatomy

While many medical disciplines have recognized the need for evidence-based data, clinical anatomy remains largely based on observations from single epidemiological-type studies that are rarely standardized reporting (Tomaszewski et al., 2017). Most reviews in clinical anatomy are narrative in nature: the bulk of anatomical literature consequently lacks the statistical power that would permit extrapolation to whole populations. We propose that evidence-based research principles and techniques should be applied to clinical anatomy (Standring, 2012; Henry et al., 2016). Evidence-Based Anatomy (EBA) relies on two complimentary components. First, EBA aims to enhance the quality of original anatomical research by standardizing and improving reporting in clinical anatomy studies (Tomaszewski et al., 2017). To this end, an international team of world-renowned anatomists, anatomical journal editors, and editors of anatomical texts and atlases, organized by the International Evidence-Based Anatomy Working Group (iEBA-WG), created the Anatomical Quality Assurance (AQUA) Checklist, to provide standardized reporting guidelines for original anatomical studies. The AQUA checklist enables reporting of methodology and results that is both reproducible and unambiguous (Tomaszewski et al., 2017). These guidelines will help to increase the internal validity of anatomical studies and enhance consistency in reporting of quantitative and qualitative data. The AQUA Checklist was designed to be applicable to all forms of anatomical research, including cadaveric, imaging, and intraoperative studies. Second, EBA employs systematic reviews (SR) and metaanalyses (MA) to provide high level assessment of primary research. It aims to synthesize more accurate, evidencebased data in order to improve clinical practice and enhance understanding of the human form (Standring, 2012; Henry et al., 2016). The AQUA Tool was designed by the iEBA-WG and its international collaborators to assess risk of bias in studies included in anatomical SRs/Mas (Henry et al., 2017b). It aims to evaluate the quality and reliability of anatomical studies on which our understanding of a particular human structure is based. Through EBA, data obtained from thousands of subjects can be analyzed and associations between anatomy and variables such as age, race, sex, side, laterality, or pathology can be evaluated. Moreover, inferences about prevalence and variation can be drawn that would not be deducible from single studies with small sample sizes (Henry et al., 2017a). It is hoped that novel insights gained from such analyses will translate into improved preoperative planning, safer procedures, reduction in the incidence of iatrogenic injuries, and more accurate interpretation of imaging examinations. Data from EBA should be incorporated into anatomical education curricula at both undergraduate and postgraduate level.

The evidence-based surgical anatomy of the popliteal artery and the variations in its branching patterns

Objective: The goal of our study was to analyze the prevalence of branching pattern variations in the popliteal artery (PA) along with morphometrics of the PA to better address its importance in disease and vascular surgical procedures. Methods: An extensive search for the PA and its anatomic variations was done in the major online medical databases. The anatomic data found were extracted and pooled for a meta‐analysis. Results: A total of 33 studies (N = 12,757 lower limbs) were included in the analysis. The most common variant was a division of the PA below the knee into the anterior tibial artery and a common trunk for the posterior tibial and peroneal arteries, with a prevalence of 92.6% (95% confidence interval [CI], 90.2‐93.8). The second most common variation was a trifurcation pattern of all three branches dividing within 0.5 cm of each other, with a prevalence of 2.4% (95% CI, 1.4‐3.5). Of the three studies that reported the diameter of the PA at the level of the subcondylar plane, a mean diameter of 8 mm (95% CI, 7.29‐8.70) was found. Conclusions: The PA most commonly divides below the knee into the anterior tibial artery and the common trunk of the posterior tibial artery and the peroneal artery. Knowledge of the prevalence of possible variations in this anatomy as well as morphometric data is crucial in the planning and execution of any surgical intervention in the area of the knee.