PMC9734007_01
Schematic diagram showing the distribution and characteristics of chronic pain. (a) The gray areas over the left hemiface indicate the distribution of pain that occurred three months prior to the patient's visit. The pain was more severe in the left periorbital, cheek, and chin, and the periorbital area was the most painful. The nature of the pain was a feeling of tightness and pressure, which lasted all day. (b) The location (gray area) of tightening and squeezing pain on the side of the left leg that occurred 5 years ago. A few days after the onset of pain in the left leg, a similar pain occurred in the patient's left arm. (c) The location of the pain in the left posterolateral neck and shoulder that suddenly worsened 3 years before admission. (d) A drawing showing the distribution of pain in the left hemiface (gray area) that suddenly occurred as the existing left posterolateral neck pain worsened. This hemifacial pain was also described by the patient as a constant pulling and tightening pain.
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A 49-year-old female patient presented with a three-month history of pain with a sudden onset, persistent tightness, and left-side facial pain, including periorbital, cheek, and jaw areas (Figure 1(a)). Within a few days after the onset of pain in the left leg, the pain extended to the left arm (Figure 1(b)). About 3 years ago, the patient's left neck and shoulder pain gradually got worse for no apparent reason (Figure 1(c)). Three months before her visit, the pain in the left posterolateral neck suddenly worsened for several days (Figure 1(c)). One day, a tingling sensation and dullness appeared suddenly on her left hemiface (Figure 1(a)). The left periorbital area was particularly painful, requiring pressure with a fist to suppress it (Figure 1(a)). As the pain in her left hemiface developed, the intensity of pain in the left extremity, neck, and shoulder also increased (Figure 1(d)).
Computed tomographic (CT) scan images showing a single incidental suboccipital osteoma (arrow). A three-dimensional CT scan (a) and an axial CT image (b) of the osteoma. No association was found between osteoma and the greater occipital nerve.
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Physical examination revealed a small, nontender, immobile, hard mass, which was palpable in the left suboccipital area (Figure 2). A small calcified mass was observed under the left suboccipital bone during simple skull radiography (Figure 2(a)). Three-dimensional computed tomography and MRI of the brain confirmed a benign osteoma without intracranial extension (Figures 2(b) and 2(c)).
Intraoperative photographs of decompression of the greater occipital nerve (GON) and osteoma removal. (a) GON (white arrows) entrapment at the trapezial tunnel. The GON entrapment is observed by lifting the trapezial aponeurotic edge (black arrows). The inset shows the direction of the image and the location of the incision. The skull reconstruction image in the inset represents the position of the head and skin incision in the surgical field. (b) Complete decompression of the GON (arrows) around the trapezial tunnel. The white circle indicates the location of the osteoma. The GON had no direct contact with the osteoma. (c) Osteoma (white arrow) exposed after retraction of the GON (black arrow). (d) Intraoperative photograph showing the decompressed GON (white arrow) after removal of the osteoma (black arrow). The patient's left hemiface, posterolateral neck, and shoulder pain, as well as pain in the left extremity, had completely improved by 2 weeks after surgery.
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In order to expose both the osteoma and the left GON, a 6 cm straight incision was made at an angle in the center of both structures (Figure 3). The GON was found severely entrapped by the fibro-tendinous aponeurotic edge of the trapezius muscle (trapezial tunnel), showing an indentation of chronic entrapment (Figure 3(a)). After the circumferential release of the GON from the tendinous aponeurotic arch, the proximal and distal courses of the left GON were dissected (Figure 3(b)). After retracting the decompressed left GON using a vascular loop, the underlying superior oblique muscle was incised to expose the protruding osteoma (Figure 3(c)). The protruding part was removed by drilling (Figure 3(d)).