Slipping Rib Syndrome
Encountered more frequently in clinical practice since the increased use of across-the-chest seat belts and airbags, slipping rib syndrome is often misdiagnosed, leading to prolonged suffering and excessive testing for intraabdominal and intrathoracic pathological conditions.
Slipping rib syndrome is a constellation of symptoms consisting of severe knife-like pain emanating from the lower costal cartilages associated with hypermobility of the anterior end of the lower costal cartilages. The tenth rib is most commonly involved, but the eighth and ninth ribs also can be affected. This syndrome is also known as the rib tip syndrome.
Slipping rib syndrome is almost always associated with trauma to the costal cartilage of the lower ribs. These cartilages are often traumatized during acceleration/deceleration injuries and blunt trauma to the chest. With severe trauma, the cartilage may sublux or dislocate from the ribs. Patients with slipping rib syndrome may report a clicking sensation with movement of the affected ribs and associated cartilage.
What are the Symptoms of Slipping Rib Syndrome?
On physical examination, the patient vigorously attempts to splint the affected costal cartilage joints by keeping the thoracolumbar spine slightly flexed. Pain is reproduced with pressure on the affected costal cartilage. Patients with slipping rib syndrome exhibit a positive hooking maneuver test.
The hooking maneuver test is performed by having the patient lie in the supine position with the abdominal muscles relaxed while the clinician hooks his or her fingers under the lower rib cage and pulls gently outward. Pain and a clicking or snapping sensation of the affected ribs and cartilage indicate a positive test.
How is Slipping Rib Syndrome diagnosed?
Plain radiographs are indicated in all patients who present with pain thought to be emanating from the lower costal cartilage and ribs to rule out occult bony pathological processes, including rib fracture and tumor.
Based on the patient’s clinical presentation, additional tests, including complete blood cell count, prostate-specific antigen level, erythrocyte sedimentation rate, and antinuclear antibody testing, may be indicated. Magnetic resonance imaging (MRI) of the affected ribs and cartilage is indicated if joint instability or occult mass is suspected. The injection technique discussed in this chapter serves as a diagnostic and therapeutic maneuver.
As mentioned earlier, the pain of slipping rib syndrome is often mistaken for pain of cardiac or gallbladder origin and can lead to visits to the emergency department and unnecessary cardiac and gastrointestinal workups. If trauma has occurred, slipping rib syndrome may coexist with rib fractures or fractures of the sternum, which can be missed on plain radiographs and may require radionucleotide bone scanning for proper identification. Tietze syndrome, which is painful enlargement of the upper costochondral cartilage associated with viral infections, can be confused with slipping rib syndrome, as can devil’s grip, which is a pleura-based pain syndrome of infectious origin.
Neuropathic pain involving the chest wall also may be confused or coexist with slipping rib syndrome. Examples of such neuropathic pain include diabetic polyneuropathies and acute herpes zoster involving the thoracic nerves. The possibility of diseases of the structures of the mediastinum is ever present, and these diseases sometimes can be difficult to diagnose. Pathological processes that inflame the pleura, such as pulmonary embolus, infection, and tumor, also should be considered.
Initial treatment of the pain and functional disability associated with slipping rib syndrome should include a combination of nonsteroidal anti inflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors and physical therapy. The local application of heat and cold may be beneficial. The repetitive movements that incite the syndrome should be avoided. For patients who do not respond to these treatment modalities, injection of the affected costochondral cartilages with a local anesthetic and steroid may be a reasonable next step.
To inject the slipping ribs, the patient is placed in the supine position, and proper preparation with antiseptic solution of the skin overlying the affected costal cartilage and rib is done. A sterile syringe containing 1 mL of 0.25% preservative-free bupivacaine for each joint to be injected and 40 mg of methylprednisolone is attached to a 25-gauge, 1½-inch needle using strict aseptic technique.
With strict aseptic technique, the distal rib and costal cartilage are identified. The lower margin of each affected distal rib is identified and marked with a sterile marker. The needle is carefully advanced at the point marked through the skin and subcutaneous tissues until the needle tip impinges on the periosteum of the underlying rib. The needle is withdrawn back into the subcutaneous tissues and walked inferiorly off the inferior rib margin. The needle should be advanced just beyond the inferior rib margin, but no farther, or pneumothorax or damage to the abdominal viscera could result. After careful aspiration to ensure that the needle tip is not in an intercostal vein or artery, 1 mL of solution is gently injected. There should be limited resistance to injection. If significant resistance is encountered, the needle should be withdrawn slightly until the injection proceeds with only limited resistance. This procedure is repeated for each affected rib and associated cartilage. The needle is removed, and a sterile pressure dressing and ice pack are placed at the injection site.
Complications and Pitfalls
The major problem in the care of patients thought to have slipping rib syndrome is the failure to identify potentially serious pathological conditions of the thorax or upper abdomen. Given the proximity of the pleural space, pneumothorax after the injection technique described is a possibility. The incidence of the complication is less than 1%, but it occurs with greater frequency in patients with chronic obstructive pulmonary disease. Because of the proximity to the intercostal nerve and artery, the clinician should calculate carefully the total milligram dosage of local anesthetic administered, in consideration of the high vascular uptake via these vessels. Although uncommon, infection is an ever-present possibility, especially in an immunocompromised patient with cancer. Early detection of infection is crucial to avoid potentially life-threatening sequelae.CLINICAL PEARLS
Patients with pain from slipping rib syndrome often attribute their pain symptoms to a gallbladder attack or ulcer disease. Reassurance is required, although it should be remembered that this musculoskeletal pain syndrome and intra-abdominal pathological conditions can coexist. Care must be taken to use sterile technique to avoid infection and universal precautions to avoid risk to the operator. The incidence of ecchymosis and hematoma formation can be decreased if pressure is placed on the injection site immediately after injection. The use of physical modalities, including local heat and gentle range-of-motion exercises, should be introduced several days after the patient undergoes this injection technique for slipping rib syndrome. Vigorous exercises should be avoided because they could exacerbate the symptoms. Simple analgesics and NSAIDs may be used concurrently with this injection technique. Laboratory evaluation for collagen-vascular disease is indicated in patients with costal cartilage pain in whom other joints are involved.