The Sacral Cup Test and adjustment can be an extremely important tool for the chiropractor because of its ability to help stabilize a chronic unstable sacroiliac (SI) joint, especially if it is slow to respond to traditional category two pelvic procedures. [Figure 1] In addition, it gives the doctor a tool to determine the presence of a complication in the treatment of a moderate sprain of the SI joint which might require additional time for recovery. A reoccurring sacral cup will also alert the doctor that an SI support belt and rehabilitative exercises will be required.
In essence, the Sacral Cup, or prone leg extension, tests the strength of the muscles crossing the posterior aspect of the SI joint. When a joint is unstable the adjacent musculature will often sacrifice strength and flexibility for stability, therefore weakness will be noted on straight leg extension, which is especially evident when the SI joint is so badly sprained that the sacrum has displaced posteriorly on one (or infrequently both) side(s). DeJarnette discussed this by noting that such weakness of the muscles crossing the posterior aspect of the SI joint contributes to confusing SI joint hypermobility response to treatment.
Sacral Cup Testing
Proper leg lift: When a patient’s joint is sufficiently sprained, they will adapt by recruiting other muscles to extend their straight leg. They will accomplish this by externally rotating their leg [Figure 2] and slightly abducting their thigh as they lift. [Figure 3] In addition, they will rock toward their "non lifting" side and lift their ipsilateral hip. [Figure 4] It is appropriate that the patient be instructed prior to beginning the test to:
1) Keep their hips on the table
2) Keep their leg straight
3) Attempt to keep the leg slightly turned inward and held near the midline as they lift. [Figure 5]
Determining leg/thigh extension strength:
With a severe SI joint sprain, the patient will be unable or have difficulty in lifting his/her leg(s) off the table or one side will not go up as high as the other. Possibly both legs individually might be able to be raised but, with doctor pressure upon the legs "toward the table," the leg(s) will be obviously weaker to some degree.
Locating the Sacral Cup
Dr. DeJarnette first described the sacral cup as being located by palpation at the posterior surface of the sacrum. He divided these cups into right or left superior and inferior "cuplike" depressions. [Figure 6] Since his work, there have been studies that have found that with some adults the sacrum does not fuse completely, allowing for some slight sacral segment malposition. This necessitates greater specificity when correcting the posterior sacral segment and expands the diagnostic and treatment region beyond just a "cup" area.
Once weakness of the leg/thigh extension has been determined, the side of sacral segment or body posteriority needs to be identified. Begin by applying posterior/anterior (P/A) pressure to the superior ipsilateral region of the sacrum on the side of weakness which, 70 percent of the time, is the main area of posteriority. [Figure 7] If, upon maintaining pressure, the leg does not strengthen, then apply pressure to the ipsilateral inferior, the contralateral superior, and the inferior aspect of sacrum respectively.
Initially, it is possible that gravity alone will be sufficient to test muscle strength. Remember that this is not about muscle strength but about an SI joint injury sufficient to permit posterior displacement of the sacrum. Patients will present with varied degrees of weakness and, as they improve, they will develop greater strength. With proper P/A pressure to the sacrum in the "right place," their leg/thigh extension weakness will eventually resolve and the muscle will appear to "lock in" appropriately.
Adjusting the Correct Segment or Sacral Cup
Once the "cup" on the sacrum is identified, the joint can be treated. Dr. DeJarnette recommended a double thumb thrust or Activator gun impulse directly into the posterior cup. For greater effectiveness, have the patient lift and slowly lower their leg while applying multiple impulses at each stage of lifting and lowering. If the ligament isn’t strong enough to hold the correction (such as chronic ligamentous compromise), sometimes the thrust, alone, will not be sufficient. In those isolated cases, you will need to apply constant P/A pressure as the patient lifts their leg and slowly lowers it to the table. Pressure must be maintained during the lowering process, since this is when the sacrum will attempt to dislodge posteriorly. Two to three leg lift attempts are generally sufficient to create some degree of improvement of function.
What does a returning positive sacral cup tell you?
Chronic sacral cup findings are commonly found with sacroiliac hypermobility syndromes (category two) presenting with a moderate to severe sprain. The patient’s recovery from this condition will not likely be rapid. Even if they have pain relief, until the posterior extensors are functioning well for one to two months, they will need to exercise caution when sitting and stressing their SI joint. The repeating positive Sacral Cup Test is indicative of two aspects of the patient’s recovery process:
(1) The need for a sacrotrochanter belt, and
(2) The need to perform leg extension rehabilitative exercises.
The SI belt can be worn in acute phases for twenty-four hours (while sleeping, compression can be reduced). As the patient’s condition improves, the belt may be needed just for sitting, lifting objects, or whenever weight-bearing stress of the joint might occur. For some patients, this might mean two weeks, for others six to eight weeks with a gradual tapering off. When the patient’s Sacral Cup Test shows up negative for one to two weeks, the need for the SI belt will decrease significantly.
SI Joint-Sacral Cup Rehabilitation
As the sacroiliac joint stabilizes in its acute phase, prone hip extension exercises are used to encourage strengthening of the joint tissues, ligament and cartilage. As our bodies age, the blood supply to the connective tissue diminishes. This "exercise" has the goal of increasing blood supply into the SI region without further traumatizing the joint tissues. Gentle lifting of the straight leg while prone is advised. If there is low back discomfort, a pillow under the stomach may help. If nothing relieves the discomfort enough to allow them to do this exercise, then they are not ready and should focus on slow walking with minimal sitting or lifting.
While lifting, the patient’s leg is maintained in a slightly adducted and internally rotated position to maximize forces into the SI joint (rather than the lateral pelvis). While lifting, the patient should attempt to keep his/her ipsilateral hip down, lifting just his/her leg, holding for a count of two, and alternating sides with each lift.
Usually a patient with a severe joint sprain will start with three sets of three, with thirty to sixty seconds of rest between each set. After a few days, if the exercise feels easy, then it is increased to three sets of five and, as that feels easier, increase it to three sets of seven. When the patient can perform three sets of ten and is pain free, they should continue at this level without further increase for three to six months. The patient should never do this exercise to any point of pain or exhaustion—it should always feel like he/she can do more but stops.
The recurring failure of a sacral cup to respond to category two pelvic block treatments, sacrotrochanter support belt, and rehabilitation indicates a problem with the patient’s recovery program. The key is that posterior segment displacement can only occur if the SI joint suffers significant compromise. Sometimes patients respond with a single treatment (without the need of a support belt) and sometimes they will be responsive during the office visit but return on successive visits exhibiting the return of the leg/thigh extension weakness.
This return of leg extension weakness necessitates reevaluation, which might just be changes in lifestyle, like making sure he/she walks frequently and avoids prolonged sitting as well as evaluating the need for nutritional support. As the patient gains strength, the need for joint support will diminish. Even so, the patient will still need to maintain sacral cup exercises for three to six months.
Once the sacral cup is negative for two weeks, you can begin the process of weaning the patient from belt use. However, if the sacral cup returns, you acted prematurely and need to reevaluate.
The sacral cup test evaluates posterior SI joint integrity and is an essential part of the category two treatments and evaluation. Examination should monitor not only for the sacral cup but also the presence of iliolumbar ligament integrity or lumbar involvement piriformis tone (anterior SI instability), and hip restriction (piriformis muscle syndrome). All these factors must be eliminated prior to leg length determination, category two-block placement, and additional treatment utilizing the SOT protocol. These procedures will be discussed in the next article.
Dr. Blum will be speaking at this year’s Chiropractic ‘07 Conference in Panama City, Panama, on "Neuromuscular Specific Diagnosis and Treatment of Severe Lumbar Herniated Discs" February 22-24, 2007. Aside from Panama City being a beautiful city at this time of the year, the warmth of everyone at the conference, and the vast array of amazing speakers make this a fabulous opportunity to come learn, share, and have fun.
Sacro Occipital Technique Organization (SOTO-USA is a chiropractic organization teaching SOT and performing research to investigate its efficacy. SOTO-USA teaches SOT as strictly developed by Dr. DeJarnette yet also continually updates the teaching of SOT based on the current research evidence base. Go to www.SOTO-USA.org for information about SOTO-USA seminars and don’t miss the 8th Annual Clinical Symposium in Nashville, Tennessee, October 25-28th, 2007.