Ewa Mizia

Anatomical variations of the formation and course of the sural nerve: A systematic review and meta-analysis

INTRODUCTION The sural nerve (SN) is a sensory nerve in the lower extremity which branches to supply the skin on the distal posterolateral third of the lower limb. Typically, the medial sural cutaneous nerve (MSCN) and the peroneal communicating nerve (PCN) unite to form the SN. Other variations in the formation, course, and morphometry of the SN have also been described in the literature. OBJECTIVE To study anatomical variations in the formation and course of the SN and establish a new classification system for formation patterns of the SN. METHODS A systematic search of all major databases identified articles that studied the prevalence of variations in the formation of the SN. No date or language restrictions were set. Anatomical data was extracted according to our new classification system where the SN is formed by: union of the MSCN and the PCN (Type 1); union of the MSCN and the Lateral Sural Cutaneous Nerve (LSCN) (Type 2); continuation of the MSCN with absent PCN (Type 3); the PCN alone (Type 4); the LSCN (Type 5); or the Sciatic Nerve (SCN) directly (Type 6). Pooled prevalence rates were calculated using MetaXL 2.0. RESULTS A total of 39 studies (n=3974 limbs) were included in the meta-analysis. The most common patterns were Type 1, Type 3, and Type 2 with a pooled prevalence of 51.5% (95% CI: 0.293-0.591), 31.2% (95% CI: 0.143-0.410), and 13.8% (95% CI: 0.035-0.234), respectively. The rest of the patterns were rare, with pooled prevalence of Types 4, 5, and 6 calculated to be 1.8% (95% CI: 0-0.063), 1.1% (95% CI: 0-0.050), and 0.7% (95% CI: 0-0.041), respectively. In 83.7% (95% CI: 0.765-0.899) of limbs, the site of union was in the lower half of the lower extremity. The pooled mean length of the SN from the formation to the lateral malleolus was 14.78 (±5.76) cm, while the mean diameter of the SN was 0.28 (±0.03) cm. CONCLUSIONS Anatomical variations in the formation and course of the SN are common in the population. Clinicians, especially surgeons, should be aware of these variations to avoid iatrogenic injury to the nerve during operative procedures.

The vascular architecture of the supravaginal and vaginal parts of the human uterine cervix: a study using corrosion casting and scanning electron microscopy

The aim of this study was to visualize and describe the vascular architecture of the vaginal and supravaginal parts of the human uterine cervix. Uteri collected at autopsy (n = 42) were perfused via the afferent vessels with fixative followed by Mercox resin. After polymerization of the resin, corrosion was performed. The obtained vascular casts of the cervix, visualizing all vessels including capillaries, were examined using scanning electron microscopy. Both in the vaginal and supravaginal parts of the cervix, four distinct vascular zones were distinguished – the outer zone containing large arteries and veins, the arteriole and venule zone, the endocervical mucosal capillaries zone and the pericanalar zone containing small veins and capillaries. In the pericanalar zone ran small veins, responsible for draining the mucosal capillaries. Both in the muscular layer, as well as in the pericanalar zone, arterioles and venules passed close to each other, often adjoining. This study introduces the idea of two systems responsible for draining blood from the mucosal capillaries. It is also the first to suggest the possible existence of a countercurrent transport between adjoining veins and arteries.

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.

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.

Contemporary views on the ossification of the ligamenta flava.

The ligamenta flava, together with the vertebral lamina, form the posterior wall of the spinal canal. Since they are located immediately adjacent to the nerve structures of the spinal cord, every pathology that involves hypertrophy produces neurological disturbances as a result. One of the most common reasons for hypertrophy of the ligamenta flava is heterotopic ossification. The main regions of the world where this disorder occurs are the Asian countries, especially Japan, but there are increasing numbers of such cases in other populations. The most important causes of the formation of ectopic osseous tissue in the vicinity of the ligamenta flava are thought to be mechanical stress and genetic predisposition. Treatment is mostly limited to surgical procedures. The present study is a review of the current state of our knowledge concerning the ossification of the ligamenta flava, the sequelae of this pathology, and the treatment methods.

The Vascular Microarchitecture of the Human Fetal Pancreas: A Corrosion Casting and Scanning Electron Microscopy Study.

Objectives Detailed knowledge on the development of the pancreas is required to understand the variability in its blood supply. The aim of our study was to use the corrosion casting method combined with scanning electron microscopy to study the organization of the pancreatic microcirculation in human fetuses. Methods The study was conducted on 28 human fetuses aged 18 to 25 gestational weeks. The fetal vasculature was appropriately prepared and then perfused with a low-viscosity Mercox CL-2R resin. The prepared vascular casts of the surface of the fetal pancreas were then examined in scanning electron microscopy and digitally analyzed. Results The lobular structure of the pancreas has a strong impact on the organization of the microvasculature. The lobular networks were supplied by the interlobular arteries and drained by the interlobular veins. The vascular system of fetal human pancreas has many portal connections, including islet-lobule and islet-duct portal circulations, which likely play a key role in the coordination of both endocrine and exocrine pancreatic functions. Conclusions The organization of the microvascular network of the human pancreas in fetuses aged 18 to 25 gestational weeks is very similar to that of an adult but with more prominent features suggesting active processes of angiogenesis and vascular remodeling.

Oblique incisions in hamstring tendon harvesting reduce iatrogenic injuries to the infrapatellar branch of the saphenous nerve

PurposeIatrogenic injury to the infrapatellar branch of the saphenous nerve (IPBSN) is associated with many surgical interventions to the medial aspect of the knee, such as anterior cruciate ligament (ACL) reconstruction. Different types of surgical incisions during hamstring tendon harvesting for ACL reconstruction are related to a variable risk of IPBSN injury. This study aimed to evaluate the risk of iatrogenic IPBSN injury during hamstring tendon harvesting for ACL reconstruction with different incision techniques over the pes anserinus.MethodsThis study was performed on 100 cadavers. Vertical, horizontal, or oblique incisions were simulated on each cadaveric limb to determine the incidence of iatrogenic IPBSN injury.ResultsThe vertical incision caused the IPBSN injury during hamstring tendon harvesting in 101 (64.7%), the horizontal incision in 78 (50.0%), and the oblique incision in 43 (27.6%) examined lower limbs. The calculated odds ratios (OR) for risk of injury in vertical versus horizontal and horizontal versus oblique incisions were 2.4 (95% CI 1.5–3.6) and 1.8 (95% 1.2–2.8), respectively.ConclusionsThe vertical incision technique over the pes anserinus should be avoided during hamstring tendon harvesting for ACL reconstruction. The adoption of an oblique incision, with the shortest possible length, will allow for the safest procedure possible, thus minimizing the risk of iatrogenic IPBSN injury, and improving patient outcomes and postoperative quality-of-life.

Anatomical variability and histological structure of the ulnar nerve in the Guyon’s canal

ObjectivesThe goal of our study was to analyze the prevalence of variations, branching patterns, and histology of the ulnar nerve (UN) in Guyon’s canal to address its importance in hand surgery, particularly decompression of the UN.MethodsFifty fresh cadavers were dissected bilaterally, and the nerve in the area of Guyon’s canal was visualized. Samples for histology were also taken and prepared. The collected data were then analyzed.ResultsMorphometric measurements of the hands and histological studies were not found to have significant differences when compared by left or right side or by sex. Three major branching patterns were found, with division into deep and superficial UN being the most common (85%). Additional findings included a majority (70%) presenting with a cutaneous branch within the canal and/or with an anastomosis of its distant branches with those of the median nerve (57%).ConclusionThe UN is most commonly found to divide into a superficial and deep ulnar branch within Guyon’s canal. However, additional branches and anastomoses are common and should be taken into careful consideration when approached during surgery in the area, particularly during decompression procedures of Guyon’s canal.

Computer-assisted assessment of the histological structure of the human sural nerve

BACKGROUND The aim of this study was to assess the histological structure (cross-sectional area - CSA, number of nerve bundles) of the human sural nerve at the level above the lateral malleolus, using computer-assisted image analysis. MATERIALS AND METHODS This study has been conducted using sural nerves dissected from cadavers during routine autopsies. The harvested tissues samples were dehydrated, embedded in paraffin, sectioned at 4 μm and stained with haematoxylin and eosin. Each cross-section was photographed (16 × magnification) and the images were analysed using Java ImageJ. RESULTS The studied group comprised 12 women and 25 men (mean age 60.1 ± 15.7 years), yielding a total of 74 sural nerves (37 right vs. 37 left). The mean ± standard deviation CSA of the sural nerve was 0.14 ± 0.07 cm2. The mean number of nerve bundles in the sural nerve was 10.5 ± 6.0. In terms of gender and side, neither the CSA (p = 0.45 and p = 0.79, respectively) nor the number of nerve bundles revealed any differences (p = 0.34 and p = 0.47, respectively). Strong negative correlations were noted between the age of the donors and the sural nerve CSA (r = -0.69,p = 0.02), as well as the number of nerve bundles (r = -0.57, p = 0.06). CONCLUSIONS This study shows that there are no statistical differences between the CSA and the number of nerve bundles in the sural nerve when compared by gender and side of the lower limb. This study also allows drawing the conclusion that the sural nerve degenerates with age in terms of both the CSA and the number of nerve bundles.

Risk of injury to the sural nerve during posterolateral approach to the distal tibia: An ultrasound simulation study: Risk of Injury to the Sural Nerve

When surgeons operate on the foot and ankle, the most common complication that may arise is injury of the cutaneous nerves. The sural nerve (SN) is potentially at risk of being injured when treating fractures involving the distal tibia using the posterolateral approach. The aim of this study was to evaluate how differences in length and position of the surgical treatment of fractures involving the distal tibia can affect the risk of SN injury. The study involved 40 healthy volunteers (n = 80 lower limbs). Ultrasound simulation of each potential surgical incision site was used to locate the SN and to assess the risk of injury. The study showed that the SN predominantly travels more posteriorly at levels more proximal from the tip of the lateral malleolus. At these more proximal points of the SNs course, it was proven that there was an overall increased incidence of iatrogenic injury to the SN in incisions made closer to the Achilles tendon. Based on these results, a quasi 3 dimensional figure was created showing the anatomical structures of this region to identify areas at high risk for SN injury. By revealing how length and position of the surgical incision can influence the risk of SN injury, we hope to provide information to surgeons on the optimal technique to avoid iatrogenic SN injury while operating on the distal tibia via a posterolateral approach. Clin. Anat. 31:870–877, 2018.