Ultrasonographical and histological cross-sectional study of the human superficial branch of the radial nerve.

PURPOSE: The superficial branch of radial nerve (SBRN) is one of the cutaneous nevus biopsied for diagnosis of peripheral neuropathy. The purpose of this study is to find out the cross sectional microanatomy of the (SBRN) at antecubital fossa for changes in the fascicular, non-fascicular components with respect to age and also to find cross sectional area of SBRN in healthy volunteers. MATERIALS AND METHODS: Sixty SBRN were harvested bilaterally from 30 fresh human bodies (25 males and five females) with ages of 37 to 88 years. Samples were divided into three age groups (G1, 37-55 years; G2, 55-70 years; G3, ≥ 71 years) and studied at different magnifications after histological processing for morphometric analysis - total cross-sectional (Asc), fascicular (Af), and non-fascicular area (Anonf). Fifteen volunteers SBRN cross sectional area was measured by ultrasonography (US). RESULTS: The SBRN was found to have 2-6 fascicles. The differences in the adipose tissue (FAT) areas, between G1 and G2 (p=0.233) and between G2 and G3 (p=0.458) were not statistically significant. However, a significant difference was seen between G3 and G1 (p=0.021). The differences in the non-adipose tissue (FAT) areas, between G1 and G2 (p=0.110), between G2 and G3 (p=0.950) and between G3 and G1 (p=0.210) were not statistically significant. The amount of adipose tissue (FAT) in the epifascicular and interfascicular region increased in elderly individuals (age ≥ 71 years). Ultrasonographic cross-sectional area ranged from 2 to 3 mm². CONCLUSIONS: Our study revealed comparatively more adipose tissue in human SBRN with advanced age (≥ 71 years). Findings may help to explain poor prognosis with advancing age following repair. SBRN ultrasonographical Asc was comparable to histological Asc in ages between 37-55 years.

Histological and ultrasonographical study of the human superficial branch of the radial nerve at distal forearm and its clinical implications.

PURPOSE: Age as poor prognostic factor following nerve repair may be due to change in intraneural anatomy with age. The purpose of this study is to find out the cross sectional microanatomy of the superficial branch of radial nerve (SBRN) at distal part of forearm for changes in the fascicular, non-fascicular components with respect to age and also to find cross section area of SBRN in healthy volunteers. MATERIAL AND METHODS: Sixty fresh human (37-88-year-old) cadaveric SBRN were collected from the distal part of forearm and studied at different magnifications after histological processing for morphometric analysis - total cross-sectional (Asc), fascicular (Af) and non-fascicular area (Anonf). Fifteen volunteers SBRN cross sectional area was measured by ultrasonography (US). RESULTS: The SBRN was found to have 6-12 fascicles. Morphometric and correlation analysis confirmed that there was a significant increase of total cross section area, with significant increase of interfascicular adipose tissue in relation to advancing age. Ultrasonographic cross-sectional area ranged from 2 to 3.3 mm². CONCLUSIONS: Our study revealed comparatively more adipose tissue in human SBRN with advancing age. These findings may help to explain poor prognosis with advancing age following repair. SBRN ultrasonographical Asc was comparable to histological Asc. Further, it is possible to find Asc of SBRN by non-invasive US study and calculate the fascicular and non-fascicular area using our histological findings.

Microanatomical and immunohistochemical study of the human lateral antebrachial cutaneous nerve of forearm at the antecubital fossa and its clinical implications.

Changes in the intraneural anatomy with age can cause poor prognosis of nerve repair in patients after nerve injury. The occurrence of Complex Regional Pain Syndrome-Type II, secondary to peripheral nerve injury, is common. The purpose of this study is to asses changes in cross-sectional anatomy of the lateral antebrachial cutaneous nerve of forearm (LCNF) at the antecubital fossa in the fascicular, nonfascicular components (adipose and nonadipose tissue), and sympathetic fibers area with respect to age. For the purpose of the study, 32 human (37-88 years) fresh cadaveric LCNF were collected from left-antecubital fossae and processed for histological, morphometric analysis [total cross-sectional (Asc), fascicular (Af), and nonfascicular area (Anonf)], and immunohistochemical method (tyrosine hydroxylase) for sympathetic fibers. The LCNF's average total cross-sectional area was 3.024 mm(2), and fascicular area was 0.582 mm(2). The average number of fascicles per mm(2) was 3.09. The cross-sectional area in the nerve was mainly occupied by nonfascicular connective tissue (80.75%). There was increased adipose tissue deposition (48.48% of Asc) and decreased collagen fibers (32.24% of Asc) in interfascicular domains without any definite relationship with age. The average sympathetic fiber area was 0.026 mm(2) within the nerve fascicular area without any correlation with age. In LCNF, there was more adipose tissue and less collagen fibers deposition in the interfascicular domains of all age cases, and this may act as an obstacle for nerve fiber regeneration on using LCNF as an interpositional nerve graft.

Distribution of sympathetic fiber areas of radial nerve in the forearm: an immunohistochemical study in cadavers.

PURPOSE: Secondary to peripheral nerve injuries, involvement of sympathetic fibers complications such as complex regional pain syndrome (CRPS) have been reported. There are limited studies on the sympathetic fibers and their distribution in the upper limb nerves. There are no reports available in the distribution of the sympathetic fibers/areas of radial nerve in the forearm. The aim of the present study was an attempt to find the distribution of sympathetic fibers in the radial nerve just above cubital fossa (RN), superficial branch of radial nerve at cubital fossa (SBRN-1) and above wrist (SBRN-2). METHODS: We have studied on 19 fresh human cadaveric RN, SBRN-1, and SBRN-2 samples. Frozen sections of these nerves were processed by immunohistochemical (tyrosine hydroxylase) method for sympathetic fibers. RESULTS: The sympathetic fibers area (Asym) was found to be more in RN when compared to SBRN-1 and SBRN-2. The comparison of the sympathetic index (SI = sympathetic fibers area/total fascicular area of the nerve) between RN and SBRN-1 (p < 0.001), RN and SBRN-2 (p < 0.001), and SBRN-1 and SBRN-2 (p = 0.016) were statistically significant. The sympathetic index (SI) for SBRN-1 was more when compared to RN and SBRN-2. CONCLUSIONS: Sympathetic fibers area (Asym) was found to be more in RN when compared to SBRN-1 and SBRN-2. The sympathetic ratio (SI) and percentage of sympathetic fibers area (Asym %) was more in SBRN-1 when compared to RN and SBRN-2. These results of the study might help to explain sympathetic system-related diseases in the area of distribution of RN and SBRN.

A comparative microanatomical study on cross sections of medial and lateral cutaneous nerves of forearm at the antecubital fossa: a cadaveric study.

BACKGROUND: The anterior branch of the medial antebrachial cutaneous nerve of the forearm (AMACN) and the lateral antebrachial cutaneous nerve of the forearm (LACN) are used as potential donor grafts for repairing sensory nerves. A higher percentage of connective tissue plays an important role in predicting prognosis after nerve repair. The aim is to perform a comparative study on cross-sectional microanatomy and age related changes in non-fascicular components of the AMACN and LACN. METHODS: Thirty six fresh human (from both sides of 14 male and 4 female) cadaveric AMACN and LACN were collected at antecubital fossae and studied at different magnifications for morphometric analysis (total cross-sectional area (Asc), fascicular area (Af) and non-fascicular area (Anonf)), after histological (Masson's trichrome stain) processing. RESULTS: AMACN and LACN belong to polyfascicular type and showed differences in amount of connective and adipose tissues in non-fascicular areas. In the AMACN, there was less adipose tissue (19.38% in Asc and 25.57% in Anonf) with more collagen fibers (57.28% in Asc and 75.57% in Anonf) and in the LACN, there was more adipose tissue (47.51% in Asc and 58.19% in Anonf) with fewer collagen fibers (34.10% in Asc and 41.76% in Anonf) in interfascicular domains. CONCLUSIONS: The amount of adipose tissue in LACN non-fascicular area was found to be high at all ages. The presence of less adipose tissue and collagen fibers in the non-fascicular area of the AMACN (below 60 years) could be used for successful nerve grafting when compared to LACN.