A computed tomography and magnetic resonance imaging study of the variations of the sciatic nerve branches of the pediatric knee: Implications for peripheral nerve blockade

Abstract

In pediatric patients, peripheral anesthetic blockade of the sciatic nerve is useful for postoperative pain relief after orthopedic procedures of the lower limb. The identification of the sciatic and its branches relative to the surrounding anatomical structures of the knee significantly contribute to the successful nerve blockade. However, reports have demonstrated complications arising from the inadequate and inconsistent understanding of the anatomy of the nerves in the knee region. In addition, the paucity of information regarding the location of the nerves of the knee throughout the pediatric development needs to be addressed in order for peripheral nerve blockades to become more readily used among the pediatric population. This clinical imaging study therefore aimed to document and analyze the relative morphometric relationship of the nerves in the knee region throughout the different stages of pediatric development. The locations of the sciatic, tibial, and common fibular nerves were measured in relation to relevant anatomical structures in 142 pediatric magnetic resonance imaging and computed tomography. A strong correlation was found between age and the distance from the common fibular nerve to the semitendinosus muscle, and thus can be used to predict stature. Significant differences were found between males and females, specifically after puberty, suggesting that sexual dimorphism emerges more distinctively at puberty. In order to predict the location of the nerves at the popliteal fossa, a regression formula using the patient's age and bicondylar width was created. These finding may have significant implications for popliteal approach of the sciatic nerve blockade in pediatric patients. Clin. Anat. 32:836-850, 2019.

Previously Unreported Sciatic Nerve Variation: Case Report

“…The sciatic nerve has a large number of variations and understanding these is important in the diagnosis and treatment of pathologies involving this nerve [13][14][15]. To our knowledge, the variant described here has not been previously reported.…”

Magnetic resonance imaging study of the sciatic nerve variation in the pediatric gluteal region: Implications for the posterior approach of the sciatic nerve blockade

“…This was an expected finding, as it correlates well with our previous study on the pediatric knee region, which demonstrated age-related morphometric changes of the femoral bicondylar width and of the sciatic nerve and its branches relative to their surrounding anatomical structures in the popliteal region. 14 When comparing sexes of each age groups, strong evidence for clinically significant differences was found (Table 1). The SN distances to sacrum (SN-S) and the most medial point of the greater trochanter at the level of coccyx (SN-F2) were longer in females, in 12-16 years and 6-11 years age groups, respectively.…”

“…The exclusion criteria included MRI scans with poor resolution (e.g., from movement, variation in posture, and fat‐suppressed scans), presence of pathology (e.g., soft tissue tumor), and/or the absence of the axial image plane. Following the exclusion criteria, a total of 84 scans (42 male and 42 female; 28 right side and 56 left side) were used in this study and the sample was grouped into three age categories (0–5, 6–11 and 12–16 years), as in the previous retrospective imaging study that determined the location of the sciatic nerve within the popliteal fossa 14 . For the 0–5 years age group ( n = 17), the mean age was 3.7 ± 1.5 years (range 0.7–5.8), for the 6–11 years age group ( n = 34), the mean age was 8.5 ± 1.4 years (range 6.2–11.0), and for the 12–16 years age group ( n = 33), the mean age was 13.7 ± 1.6 years (range 11.1–15.8).…”

“…Differing from traditional descriptions, the sciatic nerve was located significantly higher within the gluteal region. For the pediatric population, three clinical imaging studies have investigated the sciatic nerve location within the popliteal fossa, providing age‐specific formulae for the popliteal approach of the sciatic nerve blockade 2,13,14 . No study to date, however, has investigated the morphometric relationship and location of the sciatic nerve within the gluteal region relative to age.…”

Defining the popliteal fossa by bony landmarks and mapping of the courses of the neurovascular structures for application in popliteal fossa surgery

“…The difference in www.acbjournal.org relative positioning between these neurovascular structures could be due to sexual dimorphism. The positioning of nerves in the popliteal fossa have been found to show significant differences between male and female after puberty due to the formation of muscle mass [10]. Along with the relative positioning differences displayed between male and female, the superficial structures; the SSV, LCSN and MCSN display a high level of variation.…”