Journal of Orthopedic Medicine Vol 14 1992 No 1, 13
Ricker Polsdorfer MD
Paper copied from Dr Polsdorfer's website with his permission (the site has now disappeared)
Coccydynia is frequently a major component of low back pain syndromes. It is almost as frequently overlooked because the proper rectal examination is not performed. Once identified, there are several effective treatments; but if missed, much unnecessary suffering and failure results.
Low back pain has multiple causes, many of which can coexist in a single patient. Treatment must address all causes at once in order to be effective. The orthopaedic rectal examination is infrequently utilized and is essential in diagnosing coccydynia, a frequent and major component of low back pain.
The floor of the pelvis consists of the pelvic organs (rectum, lower urinary tract and internal genitals). the sacrum and coccyx, and the muscles and ligaments that support them. Of primary concern here are the coccygeus, piriformis and gemellus muscles as well as the neighbouring ligaments, the levator ani and the median perineal tendinous raphe. Indirectly and by contiguity, the hip joint with all its related structures and the lumbo-sacral complex are also involved. In addition, the path of the sciatic nerve is very important. It passes across (and sometimes through the middle of) these muscles. This relationship allows spasm or inflammation of the piriform and gemellus muscles to irritate it and produce sciatica.
The function of the coccygeus muscles and the other components of the pelvic floor is support of the pelvic organs and anchorage for the mechanical function of the low back and hip joints. The coccygeus muscles also stabilize the coccyx. The piriform and gemelli muscles are external rotators of the hips. A substantial amount of balance and support, both standing and sitting, depends directly on these structures.
Case 1: FZ is a 34 year old male weight lifter who was hit in the back by a truck and developed chronic low back pain with pain radiating into the posterior thighs. The pain was worse with most lifting and back movements. Many previous treatments by orthopaedic surgeons, physical therapists, chiropractors and masseurs from various schools had failed to improve him. No one had performed an orthopedic rectal examination until several years after his injury.
On that examination, his coccyx was found to be exquisitely tender to direct pressure from the inside (though not from the outside). The tenderness extended up along the interior sacrum as far as the finger could reach and also along the sides of the coccyx and sacro-coccygeal junction.
Treatment at first consisted of injections of bupivicaine and triamcinolone suspension into the tender areas, using a rectal finger as a guide. Relief was immediate and profound ,but temporary. After a few more such injections, the same areas were frozen using a cryo-probe. Relief lasted three months and was reproducible with repeat treatment. The patient was also prescribed appropriate physical therapy modalities (described later in this paper).
Case 2: LB is a 49 year old, 216 pound woman with a history of breaking her coccyx twice, once at age 16 and again when she was 35. In June of 1988 she fell forward and subsequently suffered from multiple pains in her thoracic and lumbar spine as well as her coccygeal area.
Examination revealed multiple tender points throughout the painful areas, including extreme tenderness on rectal examination of the entire coccygeal region. An injection of cortisone/local anaesthetic into the coccyx and surrounding areas made her "a lot better" temporarily. Consequently, a course of prolotherapy was executed, including all areas of pain from the lumbar spine down to the coccyx. At the same time, she underwent water exercises and piriform stretches, and used a coccyx cushion. The treatment was completed in March of 1990. Ten months later she stilt reports 95% relief of her pain in the treated areas.
Case 3: WM is a 54 year old man with severe coccydynia for two years, following close upon an episode of prostatitis. He complained of pain in his tail bone and down both legs. The inside of his coccyx was extremely tender to rectal palpation, though there was no tenderness posteriorly. He was treated first with local anaesthetics, then with cryoanalgesia, which provided relief for one month. The pain then returned so severely that he could not sit for more than a few minutes even with a coccyx cushion. Further local anaesthetics provided very transient relief. Finally, he received seven series of prolotherapy injections, interspersed with anaesthetic infiltration's and differential caudal anaesthetic injections for temporary relief of the increased discomfort occasioned by the prolotherapy. At this time, now one month after the last prolotherapy treatment, he is substantially relieved of his pain and able to sit for extended periods of time.
Figure 1. The Pelvic Floor
Coccydynia is rarely found by itself. The typical patient is the one with low back pain, often with sciatica down one or both legs. The pain does not often extend below the knees. Coccydynia and `piriformis syndrome' usually coexist as dual manifestations of trauma or strain to this area. "Traumatic sacro-coccygeal arthritis" and "piriform tendonitis" are more accurate labels for these two entities. A history of a fall onto the coccyx or of occiput posterior "back labour" during delivery is common. Bayne et al identifies four etiologic groups.7
Any number of other causes of low back pain - for example. lumbar facet or disc disease and sacroiliac strain - may also be present and require simultaneous attention. In addition to the usual low back pain complaints, the patients will acknowledge worsening low back pain with prolonged sitting, although they do not often volunteer that history. They will complain often of pain or tenderness over the greater trochanters of the femurs. This is because of the strain excited by the spasm of the piriform and gemellus muscles on the tendon attached there. This entity is sometimes called "trochanteric bursitis" and is often treated locally with cortisone/anaesthetic injections, although that alone may not solve the problem.
Sometimes the piriform and gemelli are overused by a certain kind of gait, common in pregnant women and other overweight abdomens. This gait is characterized by leaning backward and externally rotating the hip with each step, thereby swaying from side to side in a circular fashion to counterbalance the cantilevered anterior excess. This suggests gait alteration as a treatment (see below).
There are only two elements of the physical examination that pertain specifically to this entity. The orthopaedic rectal examination is often neglected. It takes less than two seconds and should be done with every rectal and every pelvic examination. The coccyx should be held between the index finger inside and the thumb outside and moved back and forth. Then the tendinous raphe between the tip of the COCCYX and the anus should be squeezed. Next, each depression above the coccyx should be palpated for tenderness by the index finger inside the rectum. The first depression is the S-C joint; the next is the lowest segment of the sacrum. Most examiners will be unable to reach any higher. Finally, each side of the coccyx and S-C joint should be palpated. Tenderness is all that is usually appreciated, although spasm and even swelling in the muscles may occasionally be noted.
To evaluate the origins of the piriform and gemellus muscles, because they are usually beyond reach of the rectal finger, ask the sitting patient to cross his thighs and pull each knee toward the opposite biceps brachii with his arms. The examiner can improve this manoeuvre by getting behind the patent and assisting his pull. There will be a certain angle of pull that will be very painful in the buttock and will represent piriform and gemellus spasm. Resisted hip abduction is also painful with this condition.
Treatment for this entity must be included in the approach to any low back syndrome in which it is present. It is surprising how much sciatic, lumbo-sacral and sacro-iliac pain is referred from the coccygeal structures. General measures include physical conditioning, moist heat, anti-inflammatories and analgesics. Several physical therapy modalities are specific for this condition. Stretching the piriform muscle can best be done with the patient in a sitting position in the same fashion as the examination for tightness described above. Have him cross his thighs, grab the upper knee and pull it toward the opposite biceps brachii, each stretch should last 2-3 minutes, be tightened every 20-30 seconds, and repeated 3-6 times per session, on alternate sides.
These muscles can be massaged in two ways. One with the patient prone and the therapist standing at his thighs facing him, forceful massage is directed upward with the heel of the hand or the elbow into the mid-buttock. The second, a strong finger inserted into the rectum can massage the lower of these muscles with a back and forth motion.
Figure 2. The Posterior Muscles of the Hip (The gluteus maximus overlies these muscles; the ischial tuberosity, hamstrings and posterior sacro-iliac ligaments are excluded from the diagram)
Instructing the patient to walk pigeon toed can provide a dynamic stretch of the hip rotators and is antagonistic to the damaging bow legged gait described above. In addition to general treatment measures such as conditioning, nutrition, psychotherapy, analgesics and anti-inflammatories, there are several specific measures that will help coccydynia. Local injections are the first and most effective specific treatment. A mixture of cortisone suspension and local anaesthetic (such as 40mg triamcinolone suspension in 10cc 1/4% bupivicaine) is used. A 25 gauge 1 1/2" or 2" needle is sufficiently large. From a sitting position behind a patient who is in the right lateral foetal position, the physician's left finger is inserted into the rectum as a guide (assuming injections will be given with the right hand). The tender areas are located by pressing the rectal finger into them. After cleansing the skin just above the anus, the needle attached to the syringe is inserted and directed toward the left fingertip. Pinching with the left thumb and finger can help locate the point of insertion. The needle will ideally find its way past or between the bones, allowing the injection to be given into the S-C joint or into, and just deep and shallow to the fibro-osseous junction. While about 1 cc is being infiltrated. the fluid can often be felt filling the soft tissue directly under the left fingertip. The patient will complain for a moment until the anaesthetic takes effect. The left finger is then moved to the next tender point, which may be further up the coccyx or off to either side. Again the needle is inserted until it hits bone or is felt by the inside finger. When the needle hits a tender area another injection is performed. All tender points are similarly treated; most of them will be either in the same plane as the bones and just off their edges, or in the space between the bones and the rectum. Occasionally a tender point will be found on the posterior surface of a bone.
Frequently it is possible to direct the needle through not only the S-C joint, but also through an intersacral pseudo-joint one level higher that is also tender. The physician should be aware of the proximity of the sacral hiatus and the caudal epidural space.
These injections not only are therapeutic, but can also provide much diagnostic information. separating out a major (and perhaps the only) cause of a patient's mysterious low back pain. They can be repeated as often as any cortisone injection elsewhere in the body.
Coccygectomy has been performed at this point if it appears that long-lasting relief is not being obtained, but is not recommended by this author.7,9 Rhizotomy has also been tried with poor results10, and epidural electrodes with mixed results.11 This author recommends cryo-surgery at this point if a cryo-probe is available. This piece of equipment (e.g. the Lloyd Neurostat) has a 14 or 16 gauge needle probe, the tip of which freezes with a flow of C02 or N2O. It disables terminal sensory nerves in an area roughly 3-4 mm in diameter for about three months. It also causes some scarring, which can be beneficial (see below). This probe can he placed through an IV cannula (such as an Angiocath) into the same points as the needle. Freezing each point for three minutes can produce pain relief for about three months. Cryoneurolysis of the sacral nerve roots through the sacral hiatus has also been successful.12 Cryoanalgesia has no side effects except prolonged healing of the skin incision if the freezing site is so close to the surface that the skin is also frozen. Injudiciously done, it can damage motor nerves or perforate hollow viscera or blood vessels.
Prolotherapy13 is also suitable for treating this condition since it represents chronic sprain with ligamentous insufficiency. Patients LB and WM were successfully treated with this modality.
Differential caudal epidural block provides only temporary relief of coccydynia, but it can produce prolonged relief of low back pain from intra-spinal causes such as herniated discs with inflamed nerve roots. especially when done with corticosteroid. Such a block can therefore serve as an additional diagnostic aid while also providing at least temporary treatment.
It is very likely that another piece of equipment could provide permanent pain relief. A radio frequency lesion generator (Bionics) does with heat what a cryo-probe does with cold, but the heat lesion is permanent. This machine is operated in an identical manner but has not yet been used by this author for coccydynia.
A final word of caution. Bizarre entities have been discovered in the reprehensible causation of coccygeal pain. Glomus tumors14,15, arachnoid cysts of the cauda equina16, and nerve cysts17 can all be guilty of this most unsettling affliction.
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11 Nittner K (1960) Stimulation of conus-epiconus with pisces: further indications Acta Neurochir Suppl (Wien) 30:311-16
12 Evans PJ et al (1981) Cryoanalgesia for intractable perineal pain J Soc Med 74:804-9
13 Ongley MJ et al (1987) A new approach to the treatment of chronic back pain Lancet 2(8551):143-6
14 Pambakian H. Smith MA (1981) Glomus tumours of the coccygeal body associated with coccydynia J Bone Joint Surg (Br) 63-B:424-6
15 Nutz V. Stelzner F (1985) Der Glomustumor als Ursache einer Coccygodynie Chirurg 56:243-6
16 Kepski A (1978) (Arachnoid cyst of the cauda equina) Neurol Neurochir Pol 12:109-12
17 Ziegler CK. Batnitzky S (1984) Coccygodynia caused by perineural cyst Neuro 34:829-30
The anatomical diagrams are reproduced with permission from "Anatomy and Human Movement", Butterworth-Heinemann