Emphasis is placed on spinal epidural abscess, which usually necessitates urgent surgical treatment. Failure to properly identify this lesion has led to cases of paraplegia or death from sepsis. Most often this is caused by staphylococcal infection, which is carried in the bloodstream from a septic focus (e.g., furuncle) or is introduced into the epidural space from an osteomyelitic lesion. Another important avenue of infection is the intravenous self-administration of drugs and use of contaminated needles. Rarely, the infection is introduced in the course of a lumbar puncture, epidural injection, or laminectomy for disc excision. In some instances, the source of an epidural abscess cannot be ascertained. The main symptoms are low-grade fever, leukocytosis, and persistent and severe localized pain that is intensified by percussion and pressure over the vertebral spines. Additionally the pain may radiate in a radicular distribution. These symptoms mandate immediate investigation by MRI or CT myelography and surgical intervention, preferably before the signs of paraplegia, sphincter dysfunction, and sensory loss become manifest. Small abscesses and granulomas that are the residua of previous and partially treated abscesses can be sometimes treated successfully with antibiotics alone as discussed further on and in Chap. 42 on “Diseases of the Spinal Cord.”
Intraspinal Hemorrhage (See Chap. 42)
Sudden, excruciating midline back pain (le coup de poignard or “the strike of the dagger”)—often with rapidly evolving paraparesis, urinary retention, and numbness of the legs—may announce the occurrence of subarachnoid, subdural, or epidural bleeding. The most common causes of such an event are a coagulopathy (mainly from warfarin) and a spinal arteriovenous malformation (AVM), as discussed in Chap. 44. Spinal arterial aneurysms are much-less-common underlying lesions. It should be mentioned that focal back pain of comparable intensity may mark the onset of acute myelitis, spinal cord infarction, compression fracture, and, occasionally, Guillain-Barré syndrome.
This is the name applied to pain localized to the “tail piece,” the three or four small vestigial bones at the lower-most part of the sacrum. The trauma of childbirth, a fall on the buttocks, avascular necrosis, a neurofibroma or glomus tumor, other rare tumors and anal disorders, and, of course, pilonidal cyst, can sometimes be established as the cause of pain in this region. Far more often, the source remains obscure. In the past, patients in this latter group were indiscriminately subjected to coccygectomy, but more recent studies have demonstrated that most cases respond favorably to injections of local anesthetic and methylprednisolone or to manipulation of the coccyx under anesthesia (Wray et al).
It is a safe clinical rule that most patients who complain of low back pain have some type of primary or secondary disease of the spine and its supporting structures or of the abdominal or pelvic viscera. However, even after careful examination, there remains a sizable group of patients in whom no basis for the back pain can be found. Two categories can be recognized: one with postural back pain and pain after injury, and another with aggravating psychiatric illness, but there are always cases where the diagnosis remains obscure.