Deep Gluteal Syndrome (DGS) is a specific, often misdiagnosed cause of pain felt deep in the buttock and radiating down the leg. This condition is frequently confused with “sciatica” originating from the lower back, yet it is fundamentally different because it does not involve a spinal disc or nerve root issue. DGS is defined by the non-discogenic entrapment of the sciatic nerve as it passes through the deep gluteal space. Understanding this distinction is crucial for patients experiencing persistent pain. This article aims to define and explain the mechanisms, symptoms, and comprehensive management of this unique nerve entrapment disorder.
Defining Deep Gluteal Syndrome
Deep Gluteal Syndrome is an umbrella term encompassing various conditions that cause sciatic nerve compression within the deep gluteal space. This space is an anatomical region located beneath the large gluteus maximus muscle, deep within the buttock. The designation DGS was created to move beyond the traditional diagnosis of Piriformis Syndrome, acknowledging the numerous structures capable of irritating the nerve in this area.
The anatomical boundaries of this space include the sacrotuberous ligament medially, the greater trochanter of the femur laterally, and the posterior aspects of the hip joint. The sciatic nerve, the largest nerve in the body, must navigate this region, making it susceptible to compression. This localized compression in the hip and buttock is what differentiates DGS from pain caused by a herniated disc in the lumbar spine.
Several key structures inhabit this deep space and can become sources of nerve entrapment:
- The piriformis muscle
- The gemelli-obturator internus complex
- The proximal hamstring tendons
- The quadratus femoris muscle
- Fibrous bands, gluteal vessels, and other nerves like the pudendal nerve
Any pathology affecting these components can reduce the available space, leading to mechanical irritation and tethering of the sciatic nerve.
Recognizing the Symptoms
The clinical presentation of DGS centers on deep, persistent, or intermittent pain in the buttock that may radiate down the leg. This radiating pain often mimics true sciatica, which is why DGS is frequently misdiagnosed as lumbar radiculopathy. Patients typically describe a deep ache or burning sensation localized to the posterior hip and buttock region.
A characteristic feature of DGS is that the pain is often significantly aggravated by activities that put direct pressure on the deep gluteal space or stretch the entrapped nerve. Prolonged sitting is a common trigger, especially sitting on hard surfaces or with a wallet in the back pocket, earning it the historical nickname of “wallet sciatica.” The pain may also worsen when climbing stairs or running uphill due to increased muscle activation in the region.
Neurological symptoms are also common and can include numbness, tingling, or a “pins and needles” sensation that travels down the thigh and sometimes into the lower leg. Unlike pain caused by a spinal disc issue, DGS symptoms are usually not aggravated by movements that increase intra-abdominal pressure, such as coughing or sneezing. Specific hip movements, particularly those involving hip flexion, adduction, and internal rotation, often provoke the buttock and leg pain by stretching the sciatic nerve over the compressed area.
Primary Causes of Sciatic Nerve Entrapment
The compression of the sciatic nerve in the deep gluteal space can result from a variety of distinct pathologies. Historically, the most recognized cause was Piriformis Syndrome, which is now understood to be one specific subtype under the broader Deep Gluteal Syndrome umbrella. Piriformis Syndrome occurs when the sciatic nerve is irritated by the piriformis muscle, either due to muscle spasm, overuse hypertrophy, or anatomical variations where the nerve passes through the muscle belly instead of beneath it.
Muscular pathology extending beyond the piriformis muscle is another significant cause of entrapment. Conditions like ischiofemoral impingement, where the quadratus femoris muscle becomes compressed and inflamed between the femur and the ischium, can narrow the space and squeeze the nerve. Likewise, chronic strain or hypertrophy of the hamstring origin tendons near the ischial tuberosity can also lead to proximal hamstring syndrome, entrapping the sciatic nerve in the deep gluteal region.
Trauma is a frequent precursor, as a direct fall onto the buttock or a previous hip surgery can lead to the formation of scar tissue or fibrotic adhesions. These tough fibrous bands can tether the sciatic nerve, restricting its natural gliding motion and causing irritation with movement. Less common etiologies include space-occupying lesions such as gluteal varices (enlarged veins), hematomas, or soft-tissue tumors that physically press on the nerve.
Clinical Diagnosis and Management
Diagnosing Deep Gluteal Syndrome presents a challenge because its symptoms so closely mirror those of more common lumbar radiculopathy. The diagnostic process focuses first on ruling out spinal causes using imaging like magnetic resonance imaging (MRI) of the lumbar spine. Once a disc or nerve root compression has been excluded, the attention shifts to the deep gluteal space.
Physical examination is a cornerstone of the diagnosis, involving specific provocative maneuvers designed to reproduce the patient’s pain. Tests like the Seated Piriformis Stretch or the FADIR (Flexion, Adduction, and Internal Rotation) maneuver place tension on the deep gluteal structures and the sciatic nerve. Advanced imaging, such as high-resolution MRI or Magnetic Resonance Neurography (MRN), can be used to visualize the sciatic nerve and surrounding soft tissues. This imaging helps identify muscle hypertrophy, fibrous bands, or nerve inflammation.
A diagnostic injection is often the most definitive tool. A local anesthetic is precisely injected near the sciatic nerve in the deep gluteal space, often guided by ultrasound. A temporary and substantial relief of pain following this injection strongly suggests that the deep gluteal space is the source of the symptoms.
Management typically begins with conservative treatments, including activity modification to avoid painful positions like prolonged sitting, and a structured physical therapy program. Physical therapy focuses on targeted stretching of the deep gluteal muscles and strengthening of the hip abductors and core to improve biomechanics and stability. If conservative measures fail, interventional procedures are considered, such as targeted injections of a corticosteroid and local anesthetic to reduce inflammation around the nerve. For severe, refractory cases where conservative and interventional approaches have not provided relief, surgical decompression may be necessary. This procedure involves neurolysis, or freeing the sciatic nerve by releasing the entrapping structures, such as fibrous bands or a tight piriformis tendon.