The lesser occipital nerve visualized by high-resolution sonography--normal and initial suspect findings

The lesser occipital nerve (LON) is known to contribute to headache pathophysiology alongside the greater occipital nerve (GON). While high-resolution ultrasound (HRUS) has been used to study the GON, the LON has not been extensively visualized using this method. Prior research has shown that HRUS can detect peripheral nerves with high precision. However, no prior work had resolved the LON’s anatomical features or its potential involvement in headache using HRUS. This gap motivated the current study to explore whether the LON can be reliably visualized with HRUS. The uncertainty around LON anatomy and its role in headache has limited clinical assessment. The study aimed to address this by combining anatomical dissection with HRUS imaging. This approach allowed for a detailed anatomical characterization of the LON. The lack of prior HRUS studies on the LON left a key knowledge gap in diagnostic imaging. Understanding the LON’s anatomy could improve headache diagnosis and treatment.

The researchers aimed to determine whether the lesser occipital nerve (LON) can be visualized using high-resolution ultrasound (HRUS). They also sought to identify whether HRUS could detect anatomical variations or pathologies of the LON that may contribute to headache. The study focused on confirming the anatomical feasibility of HRUS for LON imaging. They examined cadavers and volunteers to compare normal and abnormal findings. The motivation came from the need to improve headache diagnosis in patients with suspected peripheral nerve involvement. The researchers hypothesized that HRUS could provide a non-invasive method to assess the LON. They also wanted to establish baseline measurements of LON diameter for future reference. This work could help clinicians better evaluate patients with atypical headache symptoms.

The study used high-resolution ultrasound (HRUS) to examine the lesser occipital nerve (LON) in both cadavers and living volunteers. Eight anatomical specimens were used, with HRUS performed bilaterally on each. Ink marking guided dissection to confirm HRUS findings. Ten healthy volunteers were scanned to measure LON diameter. Patient charts were reviewed to identify cases with suspected LON-related headache. The LON was identified in 19 out of 20 cases in volunteers and cadavers. The average LON diameter was measured at 1.08 mm with a standard deviation of 0.30 mm. Four patients with headache in the LON territory were selected for further analysis. HRUS-guided blockade was used to confirm the peripheral origin of headache in these patients. The study combined anatomical, imaging, and clinical data to assess LON visualization and pathology.

The lesser occipital nerve (LON) was successfully visualized in 19 out of 20 cases using high-resolution ultrasound (HRUS). The average LON diameter measured 1.08 mm with a standard deviation of 0.30 mm. Four patients with headache in the LON territory were identified, and three showed anatomical interference with lymph nodes or accessory muscle bellies. HRUS-guided blockade confirmed the peripheral origin of headache in these patients. The anatomical findings matched dissection results in cadavers, validating HRUS accuracy. The LON was consistently identifiable in anatomical specimens and most volunteers. No major anatomical variations were observed in the healthy volunteers. The study demonstrated that HRUS can be used to detect both normal and suspect LON anatomy.

The study confirms that the lesser occipital nerve (LON) can be visualized using high-resolution ultrasound (HRUS). The researchers observed that HRUS may serve as a useful tool in assessing patients with atypical headache. The anatomical findings were consistent with dissection results, supporting the reliability of HRUS imaging. The LON was identified in 19 out of 20 cases, with an average diameter of 1.08 mm. Three patients showed LON interference with lymph nodes or muscle structures. HRUS-guided blockade confirmed the peripheral origin of headache in these cases. The authors suggest that HRUS could improve the clinical evaluation of headache patients. They propose that further studies may explore HRUS as a diagnostic aid for LON-related pain.