Even the careful and knowledgeable spine surgeon will encounter a variety of neurologic complications during and after routine lumbar laminectomy. These include dural and nerve root injuries; cauda equina syndrome; and formation of scar tissue, extradural and intradural (arachnoiditis). The surgeon must be prepared to identify each of these problems and deal with them effectively at the time of the procedure and in the immediate postoperative and follow-up periods. The physician evaluating the multiply-operated lumbar spine patient must use an organized approach. The origin of the problem in most instances is a faulty decision to perform the original operative procedure. Further surgery on an "exploratory" basis is not warranted in any situation and most likely will lead only to further disability. There should be definite objective findings to substantiate the patient's symptoms. The etiology of each patient's symptoms. must be accurately localized and identified. Medical status and psychosocial situation--as well as orthopedic and neurologic findings--should be evaluated at the time of the initial consultation. Once the spine is identified as the probable source of symptoms, specific features should be sought in the patient's clinical history, physical examination, and roentgenographic studies. The number of previous operations, length of pain-free interval, and predominance of leg versus back pain are the major historic signposts. The presence of a tension sign and the neurologic findings are the focal points of the physical examination. Plain roentgenograms, motion films, water-soluble myelogram, computed axial tomography, and magnetic resonance imaging with contrast have specific roles in the workup.(ABSTRACT TRUNCATED AT 250 WORDS)