Non-mechanical disorders of the lumbar spine: pathology CHAPTER CONTENTS to slip forwards. The condition occurs four times as Disorders . e217 frequently in females than in males and nearly always at the fourth lumbar level (Cyriax:3 p. 288; Rosenberg4). The Spondylolisthesis . e217 slip is never severe. This condition has been discussed in Osseous disorders . e219 Chapter 35 on the stenotic concept. Rheumatological disorders . e223 • Traumatic spondylolisthesis results from a fracture of a Infections . e224 posterior element other than the pars interarticularis. Intraspinal lesions . e226 • Pathological spondylolisthesis develops as the result of Pain referred to the back . e228 weakness caused by a local or generalized bone disease. In this chapter we discuss only the spondylolytic spondylolistheses. Disorders Aetiology Isthmic spondylolisthesis has been defined as ‘a condition in Spondylolisthesis which fibrous defects are present in the pars interarticularis, which permit forward displacement of the upper vertebrae and In 1782, the Belgian gynaecologist Herbiniaux described a separation of the anterior aspects of the vertebra from its severe case of lumbosacral luxation, which he considered as a neural arch’ (Fig. 1).5 The aetiology of this bony defect (spond- potential obstetrical problem.1 ylolysis) has been discussed for decades but it is now widely A precise definition of spondylolisthesis was first given by accepted to be the result of a congenital weakness. The defect Kilian in 18542 – a spinal condition in which all or a part of a itself is not present at birth, however, but develops in child- vertebra (spondylo) has slipped (olisthy) on another. hood, probably as the result of repeated stress and trauma.6–8 Wiltse et al9 described five major types: Stress fractures form in the weakened pars interarticularis; • Dysplastic spondylolisthesis is secondary to a congenital fibrous tissue fills the gap, and further tension enlarges the 9 defect of the first sacral–fifth lumbar facet joints, with defect. Forward slipping of the vertebral body therefore gradual slipping of the fifth lumbar vertebra. occurs most frequently between the ages of 10 and 15 years, and progression is unlikely after adolescence.10,11 The reported • Isthmic or spondylolisthetic spondylolisthesis is the most 12–14 common type of spondylolisthesis. The basic lesion is in incidence of spondylolisthesis is between 4 and 7%, although a higher incidence has been reported among Eskimos the pars interarticularis. The vertebra above can slip as the 15,16 result of a lytic process, an elongation without lysis or an (18–56%). acute fracture (subtypes a, b and c). If a defect in the pars interarticularis can be identified, but no slip has Grading occurred, the condition is called a ‘spondylolysis’. • In degenerative spondylolisthesis an advanced degeneration Spondylolysis is visualized by an oblique view of the lumbar of the facet joints and a progressive change in the spine which shows the well-known ‘collar on the Scottie dog’s direction of the articular processes allow the vertebra neck’ (Fig. 2). © Copyright 2013 Elsevier, Ltd. All rights reserved. The Lumbar Spine Superior articular facet Transverse process Inferior articular facet Superior facet Defect Transverse process Inferior facet Fig 1 • Spondylolisthetic spondylolisthesis: fibrous defects in the pars interarticularis permit forward displacement of the upper vertebra and separation of the anterior part of the vertebra from its neural arch. Facet joint Spinous process Forward slipping is best visualized on a lateral radiograph Fig 2 • The defect in the pars interarticularis is best visualized in an and the amount of listhesis is graded by the Meyerding’s oblique view (‘Scottie dog with collar’). From Magee 2008 Orthopedic th system (Fig. 3):17 the upper sacrum is divided into four parallel Physical Assessment, 5 edn, Saunders, St Louis. Reproduced by kind quarters and the degree of slipping is calculated from the dis- permission. tance that the posterior edge of the fifth lumbar vertebra has shifted on the posterior edge of the sacrum in relation to the total width of the upper sacrum. Grade I is a shift of less than Spondylolisthesis .with .secondary .disc .lesion 25%, grade II between 25 and 50%, grade III between 50 and 75% and grade IV more than 75%. As early as 1945, Key stated that symptoms in spondylolisthe- Some authors emphasize that there is a significant differ- sis were far more often caused by a disc lesion than by slip- ence in measurements when the radiographs are taken with page of the vertebra.22 The clinical features are exactly the the patient in a recumbent rather than erect position.18 same as in patients without spondylolisthesis, and nothing in the history or clinical examination arouses suspicion, except some irregularity of the spinous processes on examination. Clinical findings Radiographs carried out in the erect posture disclose the slip. It is obvious that the management of disc lesions occurring It should be emphasized that most cases of spondylolisthesis in spondylolisthetic spines is exactly the same as in those are asymptomatic. Even severe displacements may be present without bony defects. The only difference is probably the in very active patients, without the slightest discomfort. liability to recurrence of acute or chronic discodural conflicts. In a radiological study of 996 adult patients with low back As in other forms of lumbar instability, sclerosing injections pain, MacNab found spondylolisthesis in only 7.6%, which is can have a good preventive outcome after reduction has taken not significantly higher than in the population as a whole place. (4–6%).19 Therefore caution must be taken before ascribing back pain or sciatica to spondylolisthesis and the radiological demonstration of a defect in a patient with back pain does Spondylolisthesis .of .itself .causing .symptoms not always indicate that the source of the symptoms has been Spondylolisthesis can cause both backache and sciatica. The discovered.20,21 former has postural ligamentous characteristics: the ache is Spondylolisthesis can produce backache or sciatica in two central, sometimes with vague and bilateral radiation over the ways: spondylolisthesis as the basis of a secondary disc lesion lower back. The discomfort is associated more with maintain- and the spondylolisthesis itself causing symptoms. ing a particular position than with exertion. Dural symptoms © Copyright 2013 Elsevier, Ltd. All rights reserved. e218 Non-mechanical disorders of the lumbar spine: pathology Normal Grade 1 Grade 2 Grade 3 Grade 4 Fig 3 • Grades of spondylolisthesis (from Meyerding).17 are absent. There are no articular signs or symptoms; lumbar both spondylolisthesis and a disc lesion the displacement will mobility is full and painless. Root signs are also absent. The reappear. In these instances, sclerosing injections are used as a only clinical finding is a bony irregularity palpated over the prophylactic measure. spinous processes. Treatment is that for ligamentous backache Spondylolisthesis which of itself causes lumbar pain should and consists of sclerosing injections (see p. 579). always be treated non-surgically. Sclerosing injections to the Spondylolitic sciatica very much resembles a bilateral lateral ligaments often give good results. recess stenosis but the patient is much younger. Increasing pain If leg pain is a significant problem, nerve root infiltrations and paraesthesia appear in the standing position and may force can often abolish it. The patient can also be advised to wear a the patient to sit or lie down, which causes the symptoms to corset during occasional strenuous activity. If root pain cannot disappear. Dural symptoms are absent. Clinical examination be abolished by these conservative measures, surgery should reveals little: there is a normal range of movement without be considered. Surgical intervention can also be considered if pain. Root signs, such as positive straight leg raising, weakness the listhesis is progressive or the patient presents with a or sensory loss are not found (J. Cyriax, personal communica- Meyerding grade III or IV. The gold standard of surgical treat- tion, 1983; Calliauw and Van23). ment is fusion in situ.26 The different techniques for fusion The cause of sciatic pain in spondylolisthesis is unknown. have mixed and variable results27–29, and the possibility of com- The different hypotheses are: plications.30 Recently, reduction of the listhesis and stabiliza- • The forward movement of the listhetic vertebra drags on tion, whether by bilateral lateral fusion or interbody fusion, has 31,32 the nerve roots, which engage painfully against the shelf been recommended. formed by the stable vertebra below (Cyriax:3 pp. It should be remembered, however, that even in grade III 287–290). and IV listhesis, good results have been described after non- 33 34 • A fibrocartilaginous mass, with or without small ossicles, surgical treatment. Apel et al. reported on the long-term may form at the defect in the pars interarticularis. results (40 years) after surgical and non-surgical treatment of Adhesions around the nerve root and compression grade I and grade II spondylolisthesis. Of the conservatively result.24 managed patients, all functioned well. Among those undergo- ing surgery, poor results were confined to those patients in • With the forwards and downwards drop of the vertebral whom the fusion failed, and a pseudarthrosis developed (40%). body, the pedicles descend on the