Lumbar Spinal Stenosis

Although narrowing of the cervical canal has been well recognised for many years (Pallis, Jones and Spillane 1954; Wolf, Khilnani and Malis 1956; Payne and Spillane 1957; Hinck, Gordy and Storino 1964; Hinck and Sachdev 1966) a similar and equally important condition of the lumbar canal has until recent years remained relatively neglected in the literature. In 1925 Donath and Vogl first described important morphological changes in the achondroplastic spine, consisting of shortening of the pedicles and reduction of the interpedicular distance, with consequent narrowing of the spinal canal in both diameters. Such patients suffer a high incidence of cord and nerve root compression (Nelson 1972). These bony changes are caused by the basic failure of cartilage growth seen in achondroplasia and were thought to be confined to that disorder. In 1947 Sarpyener described narrowing of the lumbar spinal canal in association with spina bifida. In 1954 Verbiest drew attention to the presence of narrowing of the lumbar canal in an otherwise normal individual. He was the first to associate it with the clinical picture of bilateral radicular pain, disturbance of sensibility and impairment of motor power in the legs, brought on by walking or standing and relieved by rest-a syndrome later to be called “intermittent claudication of the cauda equina” by Blau and Logue (1961). Several papers have subsequently confirmed this entity (Epstein, Epstein and Lavine 1962; Teng and Papatheodorou 1963; Graveleau and Guiot 1964; Joffe, Appleby and Arjona 1966; Hancock 1967; Jones and Thomson 1968; Schatzker and Pennal 1968; Ehni l969a and b). Nevertheless there is still some confusion as to the exact nature of the narrowing. Verbiest (1954) reported seven patients with spinal stenosis, in all of whom the interpedicular distance was normal: he concluded that the narrowing was confined to the sagittal plane, producing a complete block as revealed by myelography. Epstein et a!. (1962) reported twenty-nine patients with symptoms related to narrowing of the lumbar spinal canal, eighteen ofwhom had a sagittal diameter of 1 5 centimetres or less. The interpedicular distance was in the lower limit of normal in ten of their patients. They stressed the significance of relative flattening of the intervertebral foramina as shown in the lateral radiograph. Teng and Papatheodorou (1963) reported thirty patients with so-called spondylosis of the lumbar spine, in three of whom they described narrowing of the lumbar canal due to reduced anteroposterior diameter. Hancock (1967) recorded the finding of short pedicles in the narrowed lumbar canal, but in his first patient he also noted a reduction of the interpedicular distance at L.4 and L.5. Schlesinger and Taveras (1953) regarded an abnormal reduction of the interpedicular distance as of great significance in their patients. Schatzker and Pennal (1968) noted that several of their patients, described as having developmental stenosis, had a reduction of the antero-posterior diameter of the lumbar canal. Clark (1969), however, stressed that the total interpedicular distance may be reduced at all levels and that this may account for considerable difficulty at operation.