Thecal Sac Impingement

What is the Thecal Sac?

Thecal sac impingement or thecal sac indentation will often lead to painful conditions, and it is itself probably just an irritating symptom of another condition. The thecal sac is filled with CSF (cerebrospinal fluid), and it is a protective membrane which covers the both the spinal cord and other important neurological structures within the body. The thecal sac works by acting as insulation and protection for nerve tissues while also fulfilling the role of a holding reservoir for spinal fluid.¹ Spinal fluid is a key part in the function of various bodily faculties. Neuroinflammation, neuroprotection, and neuroregeneration, which are all aspects of pain management, are dependent on the proper flow of spinal fluid. The fluid transports important nutrients within the body, acts as a barrier to cushion trauma inflicted upon the brain, provides a lubricant to prevent friction of the nerve roots and canal lining, and is a way to dispose of waste products. Symptoms for thecal sac effacement inlcude impairment of spinal fluid flow might be weakness, headache, tinnitus, blurring of the vision, and pain as a result of sitting or standing for an extended period of time. MRI could show an abnormality in flow which could be a result of an obstruction like an abnormality in the thecal sac.² Its parts are the inner dura and the outer arachnoid membrane. The thecal sac runs “until the S1 to S3 vertebral levels”. When the spine bends forward (flexes), it “elongates and moves upwards”. Upon spinal extension, it “shortens and moves downwards”. The thecal sac is “wider in females”.

Thecal Sac Compression and Thecal Sac Indentation

There are times when the thecal sac becomes compressed. This might be a result of herniated discs, tumors, spondylolisthesis, spondylolysis, synovial cysts, spinal canal stenosis, osteophytes, spinal fracture, spinal abscess and hematoma, caudal nerve roots, and epidural lipomatosis, to name a few possible causes of impaired function. It is actually very common for paracentral disc herniation to be blamed for the impingement of the thecal sac. This could be alarming to some patients, considering what important parts the thecal sac protects, but the neurological structures are not affected. The thecal sac can also be affected by ankylosing spondylitis and chronic adhesive arachnoiditis. Symptoms of thecal sac compression include muscle weakness, low back pain, and other clinical signs.^3,4 The thecal sac is meant to protect and insulate nerve tissues. Sometimes osteophytes or herniated discs impinge upon the thecal sac, like “a finger pushing into a water balloon”. There may not be any damage, or even noticeable symptoms, to arise from thecal sac indentation. However, if it is a particularly deep impingement, or if it goes as far as the spinal cord, then symptoms might begin arising at that point.⁵

Causes and Symptoms for Thecal Sac Effacement and Impingement

A bulging disc, osteophytes, or osteoarthritis can lead to impingement, or something pressing on another structure. The terminology associated with this problem is thecal sac impingement, or a herniated disc “providing a mass effect”, “compressing”, “displacing”, or “encroaching on the thecal sac”. While many cases have no effects, there are some patients who have their spinal cord impacted. This may lead to, “in the lower lumbar spine, severe central canal stenosis”, or even sciatica. Some patients may have issues with the lower lumbar spine, leading to compression of the cauda equina nerve roots. This could lead to those sciatica symptoms. MRI reports can be used to diagnose a thecal sac impingement.⁶Brain tumors are another possible cause of thecal sac impingement. The development of these tumors in the brain exerts additional pressure on the spinal cord and nerves, which in turn causes impingement in the thecal sac. Another part of the spine that is affected are the caudal nerve roots, causing cauda equina syndrome; a condition which is characterized by the excessive pressure and swelling of the nerves that are located at the end of the spinal cord. The size of the brain tumor, should this be the cause, affects the severity of pain. Brain trauma caused by injury may produce a similar result of thecal sac impingement through damage to the nerves and fracturing of the spinal cord.⁷

Lumbar Spine Issues

Lumbar spine anatomy includes the lower back vertebral segments, numbered from L1 to the L5 vertebrae. The lumbosacral spine is where the lower back meets the sacrum.⁸ Middle-aged and older patients can be affected by a condition called lumbar spinal stenosis, which occurs when the cauda equina roots are entrapped. Symptoms include back pain, numbness, weakness, leg fatigue, and even bladder and bowel issues. The nerve root supply to the legs, feet, and genital areas “travels in very close apposition within the thecal sac”. Compression, such as lumbar canal stenosis, could cause “dysfunction in multiple root distributions”, impacting multiple body parts.⁹The neural foramen (intervertebral foramen) is “an opening between vertebrae through which nerves leave the spine”.¹⁰ Neural foraminal stenosis is a condition of narrowing, where the foramina is constricted. This can lead to pain, numbness, weakness, and tingling. Lumbar stenosis, foraminal cervical (neck) stenosis, and thoracic (middle back) stenosis are all examples of this type of disorder. Neural foraminal stenosis could be caused by arthritis, trauma, and disc herniation or degeneration.¹¹ Some patients may have a diffuse disc bulge, which can happen, for example, in the cervical region. In this case, the thecal sac may become pinched as well. There may be no pain, or there might be “severe radicular pain”, that travels down the arm to the fingers, as could be the case with a cervical disc bulge, for example.¹²

Conservative and Traditional Medical Treatments

Disc impingements and herniation are not cured by pain medication. Even in cases where they are considered to be effective, medications tend to come with side effects that could worsen the patient’s condition. Thecal sac indentation can be treated by patients ceasing the aggravating behavior, engaging in stretches and exercises (including yoga and Pilates), chiropractic adjustments, massage therapy, and acupuncture. If conservative measures do not work, some patients may be referred for epidural injections or surgery. Before considering those more extreme measures, it may be helpful to engage in “at least 3 months of therapy” first, such as chiropractic, massage, or acupuncture.¹³ First and foremost, the patient should try to consult a medical professional in order to find out what the underlying problem is that is the cause of the thecal sac impingement in the first place. Treatment of the underlying condition could speed up the relief or almost immediately cure the effects of the impingement, which is most often a symptom of another problem. Spinal surgery should be a last resort, as the risk factors that are associated with such an invasive option most often outweigh the benefits, unless all other options of possible treatments were already explored by the patient.¹⁴ Strengthening the spine is one way to help prevent injuries from arising, and it could also assist in the treatment of those conditions which have already arisen.

Tai Chi

Tai chi has been found to be both an effective means of stress relief and benefits the overall physical body. Anxiety itself could be a source of lower back pain due to the tension that naturally accompanies extreme stress. When back pain is related to arthritis, which commonly develops as a side effect of aging as a cause of degeneration, tai chi has been found to be effective as a form of natural pain relief. Arthritis is another possible source of thecal sac impingement. Tai chi is a healthy lifestyle change that almost any patient could choose to make. The exercises do not involve any drugs, there are no extremely harmful side effects as long as the patient listens to their own body and knows their own limits, and it can be made a daily part of the patient’s routine. It can also be a social activity, should the patient choose to find a group of others who share an interest in the exercises, which are rooted in Chinese culture.¹⁵

Yoga

Yoga is another natural method of treatment for the types of underlying problems behind back pain and conditions causing thecal sac issues. Yoga also relieves not only pain but also stress that is both physical and mental. The following are several different yoga poses that are recommended to help relieve back pain and negative conditions: cat-cow pose, downward facing dog, extended triangle, sphinx pose, cobra pose, locust pose, bridge pose, and child pose, among many others. Each pose could be held for an extended period of time and repeated several times. Patients could add yoga to their daily routines, following a series of poses in the mornings, afternoons, and evenings. They should follow recommendation from their doctor about overexertion, especially in the early days of practicing this type of exercise, and stretching, which may be a new activity for some patients. Studies have shown decreases in pain intensity and increased functioning in patients who participated in yoga routines. Yoga is another practice where the patient could both perform the moves at home or in a social setting, such as at a class in a professionally run studio. The patient could find support in others who share their pain as an additional source of mental support.¹⁶

Acupuncture

Lower back pain, a symptom of the thecal sac impingement symptom, could also be relieved through acupuncture. Acupuncture has been shown, in a recent study review, to provide some form of relief for chronic back pain when compared to “sham” treatment, although other studies showed that “both actual acupuncture and sham acupuncture are more effective” than standard treatment”. Acupuncture is an alternative therapy that produces varying results, but there is a chance that it could help some patients. This relief option, which is rooted in Chinese medicine, dates back over two thousand years, and it is supposed to stimulate the body’s flow of energy, which is actually most likely the body’s central nervous system. A release of chemicals triggered by the therapy might affect the muscles, spinal cord, and brain, altering how the body experiences the pain. “Acupuncture has fewer adverse side effects than many of the standard treatments for back pain”, and there are very few cases of serious injuries reported following treatment. Patients should seek out an experienced, trained acupuncturist who has been licensed, in order to experience a procedure that is generally safe. The American Academy of Medical Acupuncture may be contacted for the name of a local, licensed acupuncturist. The patient’s doctor could have recommendations for a trusted acupuncturist if other treatment options have proven to be ineffective. Those who are pregnant, use a pacemaker, are taking medications, or have any other type of implant should take these into consideration before receiving acupuncture. Expected number of treatments and cost should also be considered.¹⁷

Chiropractic Treatment

Spinal stenosis, the spinal canal narrowing, may lead to muscular or sensory weakness. Cervical spinal stenosis is said to be “dangerous because it involves compression of the spinal cord”. While a bulging disc is considered “part of the normal aging process”, a herniated disc is different. It means that there is a “crack in the…outer layer of cartilage” that “allows some of the softer inner cartilage to protrude out”. Other names for herniated discs are slipped or ruptured discs. Herniated discs are more likely to cause pain. It could be best to treat patients with ice and heat, perhaps avoiding deep tissue work, at first. Craniosacral therapy, isometrics (instead of range of motion movements), and light traction may also be useful. Patients should also practice proper ergonomics, posture, and lifestyle modifications at home. Since there is generally MRI data, chiropractic and massage treatment can be more successful. Even so, “if any motion or position or technique further aggravates the client’s symptoms, it should be immediately stopped”. Chiropractic treatments that might benefit the patient may include hot and cold therapy, electrical stimulation, ultrasound, and adjustments. Patients should listen to their medical doctor before trying any especially taxing new lifestyle changes and routines. They should also remember to listen to their own mind and body in order to avoid overexertion and unnecessary injury. There is no harm in starting a new routine slowly before an endurance is developed to further increase the duration.¹⁸