Superior gluteal neuropathy

Superior gluteal neuropathy or superior gluteal nerve injury can be the result of nerve compression or traction injury of the superior gluteal nerve under the roof of the greater sciatic foramen.

Epidemiology

Superior gluteal nerve neuropathy is uncommon and often associated with iatrogenic injury ¹.

Diagnosis

The diagnosis might be made by a combination of clinical symptoms and abnormal electrodiagnostic testing. Denervation changes in the gluteus minimus, gluteus medius and tensor fasciae latae muscles on imaging can further support the diagnosis. Lumbosacral radiculopathy, plexopathy and sciatic neuropathy should be ruled out ¹.

Clinical presentation

Clinical presentation includes weakness in hip abduction and external rotation with limping gait ^1,2. Clinical examination will reveal a positive Trendelenburg sign with a pelvic tilt towards the strong side ^1,2.

Abnormal electrophysiologic studies are another feature ².

Pathology

The superior gluteal nerve is formed by the L4-S1 nerve roots supplying motor innervation to the gluteus minimus, gluteus medius and tensor fasciae latae muscles and exits the pelvis through the greater sciatic foramen above the piriformis muscle ^1-3. It features a high variability in branching patterns making it susceptible to iatrogenic injury ¹.

Etiology

Potential causes of superior gluteal nerve injury include the following ^1-3:

• iatrogenic injury
  • hip surgery (total hip replacement, percutaneous iliosacral screw placement)
  • intramuscular injections
• acute traumatic injury
• chronic compression
  • osteophytes
  • fracture-related bony outgrowth or heterotopic ossifications
  • inflammatory processes e.g. sacroiliitis
  • tumors
  • iliac artery aneurysm

Radiographic features

MRI

Depiction of the superior gluteal nerve is challenging and therefore denervation changes seen in the gluteus minimus, gluteus medius and tensor fasciae latae muscles such as muscle edema, muscle atrophy and fatty degeneration are the best clue to the diagnosis ^2,3.

Radiology report

The radiology report should include a description of the following:

• abnormal appearance of the superior gluteal nerve and location
• denervation changes
• etiology of nerve compression

Treatment and prognosis

Management depends on the etiology and includes conservative measures including physiotherapy, stretching local anesthetics and non-steroidal anti-inflammatory drugs. Surgery might be required for the removal of space-occupying lesions and involves decompression and neurolysis.

Differential diagnosis

The differential diagnosis of sacral neuropathy includes ^1-3:

• lumbar spinal canal stenosis
• L5 or S1 radiculopathy
• lumbosacral plexopathy
• sciatic neuropathy