Steroid injections and physical therapy could not alleviate the patient’s neurologic symptoms.
A 71-year-old woman presented to our pain-management practice with complaints of low-back pain as well as right-leg numbness and tingling, from which she had suffered for years.
Following an L4-5 lumbar laminectomy performed in 1993, she had been doing well until approximately one year before. The patient stated that the pain had returned (with worsening of her radicular symptoms) after a recent canyon hike. Her neurologist initiated a battery of tests, including x-rays and an MRI, which showed a 5-mm Tarlov cyst at T12-L1 with mild-to-moderate neural compressive disease. A moderate disk protrusion that lateralized to the right at L4-5 also appeared to be causing some moderate neural compressive disease at that level.
The patient underwent a series of three epidural steroid injections weekly for a three-month period along with a regimen of nonsteroidal anti-inflammatory drugs (NSAIDs). Her relief was minimal and temporary and returned after her next hike. Three months of physical therapy also provided only minimal relief.
The patient’s pain and radicular symptoms were worse with squatting, walking down stairs, standing and walking for long periods of time, and moving from a sitting to a standing position. Her past medical history consisted of atrial fibrillation, hypertension, and Helicobacter pylori infection. Medications included losartan (Cozaar), metoprolol (Toprol), rabeprazole (Aciphex), pregabalin (Lyrica), metoclopramide (Reglan), and an NSAID, the name of which she could not remember. Her past surgical history included the aforementioned lumbar laminectomy, right shoulder surgery five years ago, and childhood appendectomy.
When she arrived at our office for more physical therapy and a medical examination, she expressed fear that her symptoms were worsening and felt she was running out of hope for relief.
The woman presented with an antalgic gait and appeared to be in some discomfort. She rated her pain as 7/10 “all the time.” Positive findings included tenderness to palpation of her lower lumbar area, especially on the right side. She had limited flexion and extension of her lower back secondary to her pain and a decreased patellar reflex on the right. The patient also could do right great toe flexion only weakly and demonstrated a positive straight-leg raise on the right in the prone position. She had an old vertical surgical scar over her lower lumbar area. The remainder of the exam was unremarkable. Her new lumbar MRI showed that the Tarlov cyst was now 9 mm at its greatest dimension (Figure 1). The prior disk protrusion was unchanged.
Diagnosis and treatment
Even though Tarlov cysts were first identified in 1938, scientific knowledge about these growths is still limited. The cysts are fluid-filled sacs that develop between the perineurium and the endoneurium of spinal nerve roots at the junction of the nerve root and the dorsal root ganglion. They have been found to occur in 5%-9% of the adult population. However, they are only symptomatic in approximately 1%, so the diagnosis could be missed based on physical exam alone. Most of these patients present as typical low-back pain sufferers.
Tarlov cysts can compress the nerve roots, causing a multitude of symptoms, including but not limited to:
• Pain in the area of the nerves affected by the cysts, especially in the buttocks
• Muscle weakness
• Difficulty sitting for prolonged periods
• Loss of sensation on the skin
• Loss of reflexes
• Changes in bowel function
• Changes in bladder function, including increased frequency or incontinence
• Changes in sexual function
• Sciatic pain
The cysts may become symptomatic following shock, trauma, or exertion that would cause a buildup of cerebrospinal fluid. Women are at a much higher risk than men of developing these cysts.
The question of optimal treatment remains controversial. Physical therapy and NSAIDs provide some short-term symptomatic relief. As we progress along the interventional scale, compressive radiculopathy can be relieved with selected nerve-root blocks. There may also be some benefit with pulse radiofrequency, but studies are still pending. Neurosurgical treatments include CT-guided aspiration (which is the least invasive but has a higher recurrence rate), decompressive laminectomy, cyst excision, and microsurgical cyst fenestration and imbrication. Surgical excision is difficult and rare.
A multitude of conditions can cause back pain with radiculopathy. Conducting a thorough history and physical exam and obtaining the appropriate radiologic studies can aid immensely in identifying the correct diagnosis. It is when there is a combination of pathologies that clinicians must sort through the myriad of possibilities in order to determine the proper treatment for each entity. NSAIDs, rest, ice, physical therapy, and epidural steroid injections are the gold standard for bulging and herniated disks. However, the diagnosis of a Tarlov cyst presents its own unique set of problems.
Treatment with physical therapy, ice, and NSAIDs yielded no improvement in our patient’s level of pain. She was referred to a neurosurgeon and has not been back to our clinic since.
Mr. Hopper is a pain-management physician assistant with Associated Physicians Group in O’Fallon, Ill.