A 47-year-old female presented with a 3 month history of non-specific, progressively worsening, sharp buttock pain which was exacerbated by exercise and relieved by rest. On clinical examination there was weakness in abduction of the hip on the right side. No obvious cause was identified.
MRI was used to confirm the diagnosis of right superior gluteal nerve impingement in this case. Coronal and sagittal images from T1 weighted and STIR sequences are displayed highlighting subacute superior gluteal nerve impingement. Using MRI, it was not possible to directly visualise the nerve entrapment. However, the nerve impingement was indirectly visualised as hyper-intensity of right tensor fasciae latae, gluteus medius and gluteus minimus muscles on STIR sequences (Fig 1, Fig 2 and Fig 3). On T1 weighted images there was mild increase in signal intensity in right tensor fasciae latae, gluteus medius and gluteus minimus, indicating fatty changes (Fig 4, Fig 5 and Fig 6).
The superior gluteal nerve (SGN) is formed by the posterior roots of L4, L5, and S1 [1]. It exits the pelvis between the upper surface of the piriformis muscle and osseous border of the greater sciatic foramen; entering the deep gluteal space [1]. As the SGN supplies motor branches to the gluteus medius and minimus, nerve injury usually manifests as weakness in abduction of the hip and a Trendelenburg gait [1]. It doesn’t have any sensory branches [2].
Injury to the SGN is common during the direct lateral approach to the hip during arthroplasty [3, 4, 5], due to local buttock trauma, pelvic fracture, and after buttock injections [6, 7]. It may also occur due to compression by anterior-superior tendinous fibers of the piriformis muscle [8] or by prominent osteophytes, bony excrescences related to fractures, and infectious and inflammatory processes, as it exits the pelvis [9].
MRI is the imaging modality of choice with regards to the presence, extent of and site of nerve injury, and differentiating between surgically treatable and untreatable causes [1, 10]. The degree and duration of injury determines the extent of neural recovery [9].
The SGN can be seen on coronal and sagittal images as it exits the pelvis, along the bony brim, in the suprapiriformis foramen [1, 9], and on axial images as it travels laterally through the fat plane between the gluteus minimus and medius muscles [1]. On T1-weighted MR images, nerves have intermediate signal intensity, while being isointense or mildly hyperintense to muscle on T2-weighted and short inversion time inversion-recovery (STIR) [9] primarily due to normal endoneural fluid [11].
Motor neuropathy in gluteus medius and minimus can used to indirectly visualise SGN impingement [12]. In acute and subacute presentation, this will appear as high-intensity for denervated muscles on T2-weighted and STIR images, while appear as normal intensity on T1 weighted images [13]. The normal architecture and size of the muscle are still preserved, with no abnormalities of subjacent fascia. As the denervation progresses, intensity of the muscle on T1-weighted image will increase [9]. In chronically denervated muscles, atrophy and fatty replacement[14], manifests as non-specific increase in signal intensity on both T1 and fluid sensitive images, indicating irreversibility [9].
Teaching point:
SGN entrapment is a cause of hip pain which may be easily missed. Knowledge of nerve pathway and distributions are necessary to correctly visualise, directly or indirectly, SGN entrapment.
Written informed patient consent for publication has been obtained.
Subacute superior gluteal nerve entrapment
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Based on the provided MRI images (including axial and coronal sequences), it can be noted that the patient’s right gluteal region (primarily involving the gluteus medius and minimus) displays relatively high signal intensity on T2-weighted and STIR sequences, suggesting the possibility of acute or subacute nerve innervation dysfunction leading to edema/inflammatory changes in these muscles.
Meanwhile, on the axial images, a mildly enhanced signal can be observed along the local path of the Superior Gluteal Nerve (SGN) compared to the surrounding soft tissue, indicating potential nerve compression or involvement.
No significant mass, fracture, or other large lesions explaining the local signal abnormalities are identified. The overall morphology of the pelvis and hip joint structures appears well-maintained, with smooth articular surfaces and no evident bony destruction or extensive soft tissue invasion.
Considering the typical clinical features of “gluteal pain and hip abduction weakness,” which worsen with activity and improve with rest, along with MRI indicative of acute/subacute neurogenic changes in the gluteus medius and minimus, the most consistent diagnosis is:
Superior Gluteal Nerve Entrapment (Compression) Leading to Neuropathic Changes.
1. Conservative Treatment:
• Rest and Avoid Triggering Activities: Avoid prolonged excessive weight-bearing or repetitive intense hip movements to reduce mechanical irritation of the nerve.
• Medications: Under the guidance of a specialist, NSAIDs may be used to alleviate pain and inflammation, along with muscle relaxants or neurotrophic agents to help improve symptoms.
• Physical Therapy: Ultrasound therapy, heat therapy, or other physical modalities to improve local blood circulation and reduce nerve edema in the gluteal region.
• Nerve Block or Injection Therapy: For stubborn pain, consider ultrasound- or CT-guided local nerve blocks or steroid injections to reduce inflammation and adhesion.
2. Surgical Treatment:
If a specific cause of nerve entrapment is confirmed (e.g., bony spur, severe muscle fibrosis, or other structural compression) and conservative treatment is ineffective, surgical decompression may be considered. Additionally, if imaging or clinical evidence indicates a lesion causing nerve compression, surgery can potentially improve symptoms.
3. Rehabilitation and Exercise Prescription (FITT-VP Principle):
(1) Early Stage: Primarily focus on protecting the affected side, limiting excessive stretching, and incorporating passive or mild active exercises.
- Frequency (F): 3–4 times per week, or on alternate days.
- Intensity (I): Low to moderate; avoid significantly exacerbating pain. Perform isometric gluteal contractions (e.g., slight leg lifts while standing, tightening the gluteal muscles), 6–8 repetitions per set.
- Time (T): Each session lasts about 15–20 minutes, possibly combined with physical therapy or local massage.
- Type (T): Emphasize core stability and avoid deep squats or other movements that significantly load the gluteal region. Include light hip abduction exercises to activate and maintain gluteus medius/minimus function.
- Volume (V): Gradually increase the number of sets as tolerated, starting from 2–3 sets and progressing to 3–5 sets.
- Progression (P): Once symptoms improve, extend the training duration, increase the abduction angle, or incorporate small resistance tools such as resistance bands.
(2) Middle to Late Stage: As pain alleviates and abduction strength improves, gradually increase exercise difficulty to strengthen power and endurance.
- Activities may include single-leg stance balance exercises, side bridge, or other core strengthening moves.
- If the patient’s overall condition permits, moderate resistance training (e.g., dumbbells or resistance bands for hip abduction) and stability exercises (such as kneeling lateral leg lifts) can be introduced.
- Continue to avoid high-impact activities (e.g., deep squats, intense running or jumping) that may trigger severe pain or an acute flare-up.
Disclaimer:
This report is based on the provided clinical and imaging information and is for reference only. It does not replace in-person consultations or professional medical advice. If you have any questions or if there are any changes in your condition, please seek medical attention promptly.
Subacute superior gluteal nerve entrapment
