In Type II Scheuermann’s kyphosis, the typical clinical features are diminished lumbar lordosis (flat back) ( Fig. 5f) or a very mild lumbar kyphosis, stiffness of the lumbar spine, and local pain. Diagnostic Work-up Imaging Studies The definitive diagnosis of juvenile kyphosis can often be made by conventional radiographs alone. However, MRI best shows endplate abnormalities, premature disc degeneration, and vertebral wedging. Computed tomography very seldom provides additional information and is rarely indicated. Standard Radiographs Juvenile kyphosis is diagnosed on standard radiographs Plain lateral and posteroanterior radiographs of the whole spine with the patient in the standing position are the primary radiological investigations. In the lateral pro- jection a more or less sharp hyperkyphosis of the thoracic spine with compensatory lumbarhyperlordosisisseen( Fig. 4b ). If necessary, close-up radiographs are taken or MRI is performed to elucidate the bony structures in the area of interest. The vertebrae around the apex of the thoracic kyphosis show typical radio- graphic changes ( Fig. 6): irregularity of the endplates wedging of vertebral bodies increased length of vertebral bodies loss of disc space height Schmorl’s nodes (not pathognomonic) a bc d Figure 6. Typical radiographic features (Type I) Wedge shape and increased sagittal diameter of vertebral bodies, irregularity of endplates, and disc space narrowing: a schematic drawing; b radiographic example. Radiographic changes with age: c 14-year-old boy and d 17-year-old boy. Juvenile Kyphosis (Scheuermann’s Disease) Chapter 28 775 Thoracic kyphosis and lumbar lordosis are measured according to Cobb. The posteroanterior radiograph is checked for secondary scoliosis. Sagittal and fron- tal spinal balance is assessed. Extension films of the kyphotic area obtained with the patient in the supine position with a sandbag under the apex of the deformity are used to assess flexibility of the deformity. In the immature patient, the skeletal age and the remaining spinal growth are determined from a radiograph of the hand and wrist [24] and the pelvis (Risser sign) for assessment of the risk of pro- gression and treatment decision-making. Magnetic Resonance Imaging In juvenile kyphosis, MRI is the imaging modality of choice to demonstrate: irregularity of the ossification wedge shape of the vertebral bodies ( Fig. 7) premature degeneration of intervertebral discs Schmorl’s nodes spinal cord compression at the curve apex (in severe cases) MRI is indicated in unclear cases or for surgical planning MRI of the whole spine should be performed if spinal cord compression, congen- ital anomalies, tumor or infection is suspected. For safety reasons, MRI is included in the preoperative work-up even if the patient’s neurology is normal. There is no indication for an MRI on the first visit if the patient’s clinical neuro- a bc Figure 7. MRI findings a MRI characteristics of juvenile kyphosis at different ages. In a 14-year-old boy (same as Fig. 5c), endplate defects, disc narrowing and disc dehydration are visible. In a 17-year-old boy (same as Fig. 5d), b vertebral wedging and disc space narrowing is more pronounced. In a 57-year-old male the final stage is visible. Note kinking of the myelon over the apex of the relatively sharp-angled kyphosis. c The patient has no neurological symptoms. 776 Section Spinal Deformities and Malformations logical examination is normal, plain radiographs show the typical picture of juvenile kyphosis and observation or non-operative treatment is planned. Neurophysiological Tests SSEPs and MEPs are helpful in identifying spinal cord compromise Somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) are obtained in patients with neurological symptoms and in connection with preoperativework-up.MEPsareofgreaterimportanceasinkyphoticdefor- mities cord compression is to be expected mainly from the anterior direction affecting primarily the motor tracts. Pathologic evoked potentials should alert the surgeon. The spine should be stabilized and, depending on the clinical situation and the imaging findings, anterior decompression should be consid- ered. Lung Function Test The data in the literature on lung function in juvenile kyphosis are sparse. Mur- ray et al. found in their long-term follow-up of untreated patients decreased vital capacity only in cases with a kyphosis exceeding 100 degrees [44]. Differential Diagnosis (Table 3) Several clinical entities must be differentiated from juvenile kyphosis: Roundback is an important differential diagnosis Idiopathic thoracic hyperkyphosis (“roundback”, “poor posture”) (Fig. 8) Clinically, postural thoracic hyperkyphosis is mobile, more harmonic, and not as localized as Scheuermann’s kyphosis. On radiographs, there is no wedge deformation of vertebral bodies. Disc space height is not decreased. Usually, the deformity corrects on extension. Congenital kyphosis A defect of segmentation is sometimes difficult to see on lateral radiographs especially if it is incomplete. The anterior bar may still not be ossified. If the disc spaces are not clearly visible on plain radiographs in a rigid kyphosis, MRI should be performed. Skeletal dysplasias Different forms of systemic skeletal diseases can be ruled out based on the history, clinical appearance of the patient, and radiographs of long bones, joints, etc. Infection and tumor The patient’s history, pain pattern, and clinical presentation should raise suspicions. Laboratory tests, radiographs, MRI, and (if necessary) biopsy will provide the diagnosis. Table 3. Differential diagnosis of juvenile kyphosis idiopathic hyperkyphosis (“roundback”) neuromuscular (paralytic, spastic) spinal cord tumor post-laminectomy kyphosis post-traumatic kyphosis connective tissue disorders congenital kyphosis skeletal dysplasia infection (tuberculosis, pyogenic, fungal) tumor Juvenile Kyphosis (Scheuermann’s Disease) Chapter 28 777 a b c d e Figure 8. Idiopathic thoracic hyperkyphosis Idiopathic thoracic hyperkyphosis (“roundback”) in a 19-year-old male. a Tho- racic kyphosis is increased b but harmonic in flexion. The patient suffers from thoracic back pain during prolonged standing and sitting. He is neurologically intact. c On the standing lateral radiograph the thoracic kyphosis measures 66 degrees. There are no structural vertebral changes. d On the supine exten- sion radiograph, the kyphosis has corrected to 26 degrees. e There are no path- ologic changes on MRI. 778 Section Spinal Deformities and Malformations Non-operative Treatment The general objectives of treatment are shown in Table 4. Table 4. General objectives of treatment to prevent progression to correct severe deformity to relieve pain to improve cosmesis The choice of the treatment modality in Scheuermann’s kyphosis depends on: age of the patient degree of the kyphosis subjective symptoms The vast majority of patients with juvenile kyphosis can be treated non-surgi- cally. Favorable indications for non-operative treatment are shown in Table 5. Physical exercises may influence pain but not the kyphosis They include exercise, bracing and casting.However,physicalexercisehasnot been shown to be clinically effective in terms of kyphosis improvement. It offers the advantage of increasing the patient’s awareness of his or her own condition. Physiotherapy combined with strengthening exercises of the paraspinal muscles and stretching of abdominal and chest muscles is of value in painful patients dur- ing and after the growth spurt. Table 5. Favorable indications for non-operative treatment radiologic signs of the disease are present before/during the growth spurt mobile curves painful curves When consulting patients on the most appropriate treatment, a thorough knowl- edge of the natural history is mandatory. The results of treatment must be weighed against natural history. Natural History The natural history of juvenile kyphosis is benign The natural history of the deformity is benign in the majority of cases. Murray et al. reported on the natural history of Scheuermann’s disease over a 32-year period [44]. Patients’ pain was usually mild and rarely interfered with daily activ- ities or professional career. Cardiorespiratory problems were seen only in very severe deformities (kyphosis >100 degrees). In kyphosis of more than 70 degrees the cosmetic impairment is considerable and clinical symptoms are more com- mon. In these cases, further progression of the deformity can be expected during adult life due to the unadvantageous biomechanical situation. However, no data Curve progression is not observed after the end of growth on the risk of progression after cessation of growth could be found from the liter- ature. The cosmetic appearance may cause psychological distress to the patient. There are no specific data on psychological problems in these patients. But it is known that patients with idiopathic scoliosis are self-conscious about their body shape and cosmetic appearance [18, 22]. The patient’s cosmetic concerns there- fore often play a role in the decision-making toward operation. Neurological deficits rarely occur in juvenile kyphosis Neurological problems are rare in Scheuermann’s kyphosis. If neurological complications occur, they are usually due to mechanical compression of the cord at the apex of the kyphosis. Normelli et al. reported on one such observation in Juvenile Kyphosis (Scheuermann’s Disease) Chapter 28 779 a 20-year-old male and collected 16 additional cases from the literature [50]. The majority were teenagers or young adults. Interestingly, male gender was overrep- resented. This was attributed possibly to the fact that the adolescent growth spurt occurs later in boys than in girls and progression is possible still during early adulthood. The kyphosis was not very severe, ranging from 37 to 80 (mean A neurological deficit is usually correlated with a sharp-angled kyphosis 56) degrees but was usually sharp-angled. There was no obvious correlation between the degree of kyphosis and the neurological deficit. Anterior decom- pression with fusion was the most common treatment with good results in the majority of patients. Other possible reasons for neurological complications in Scheuermann’s kyphosis are a coincidental disc herniation, or other spinal pathology, e.g., extradural cyst [6, 13, 17, 38, 59, 76]. Bracing and Casting Bracing has a significant psychological impact and is therefore not harmless It is well known from scoliosis patients that bracing can cause substantial psy- chological distress in an adolescent child [20, 42, 49, 54] and should therefore not be considered a harmless treatment. It has, however, also been shown that these adverse effects do not occur if the patient is well supported by the family [52] ( Case Study 1). The indication for bracing should be based on correct indica- tions, i.e.: a mobile kyphotic deformity over 45 degrees substantial remaining growth (>1 year) abcd Case Study 1 A 15-year-old otherwise healthy boy was referred by the school doctor. Within 1 year, he had developed a thoracic hyper- kyphosis with disturbing thoracolumbar pain at rest, exacerbating after activity. There was no radiating pain ( a). During physical examination a mobile slightly painful hyperkyphosis reaching from the midthoracic to the upper lumbar spine was noticed. Bilateral hamstring tightness was 45 degrees. No pathologic neurological signs were present ( b). On the standing lateral radiograph, thoracic kyphosis measured 85 degrees with typical Scheuermann’s changes from T6 to L2 ( c). The standing posteroanterior film did not show anything pathologic ( d).Onthesupineextensionradiograph,thekypho- sis decreased to 44 degrees. 780 Section Spinal Deformities and Malformations e fgh Case Study 1 (Cont.) As the kyphosis was very mobile and a considerable amount of growth was left (Risser 0, skeletal age 13.5 years), brace treatment (23 h/day) in combination with spinal extensor muscle strengthening exercises was started. The deformity corrected in the brace to 44 degrees ( e). The compliance of the patient was excellent. Weaning from the brace was started after 2 years of treatment. One year after weaning, the patient was free of symptoms. Thoracic kyphosis mea- sured 47 degrees ( f). Sixteen years after weaning, the patient is free of symptoms. The cosmetic appearance is acceptable ( g). On the standing lateral radiograph, the thoracic kyphosis measures 58 degrees (h). During growth, brace treatment is indicated for mobile deformities over 45 degrees Bracing and/or casting is known to become ineffective once the patient’s Risser signis4or5.Bradfordetal.reportedontheresultswiththeMilwaukeebrace treatment [14, 60]. Compliant patients had stabilization or a slight improvement of their deformity. Patients with initial curves above 75 degrees required surgery in 30% of cases [14, 60]. Montgomery and Erwin treated 39 patients with a Mil- waukee brace for 18 months on average. The mean kyphosis at the beginning of treatment was 62 (43–87) degrees. At the end of brace treatment, mean kyphosis measured 41 degrees. During follow-up, they saw on average a loss of correction of 15 degrees. Thus, the final mean result was 54 degrees [43]. Soo et al. stated in their long-term follow-up study that patients treated by bracing or surgery had improved self-image. Patients with kyphosis over 70 degrees at follow-up had an inferior functional result [66]. Because of compliance problems with the Milwau- kee brace, other braces such as the modified Boston or the modified Milwaukee have been tried and have also been shown to be effective. Gutowski and Renshaw usedaMilwaukeebraceandaBostonlumbarorthosis.Forcompliantpatients they achieved an average kyphosis improvement of 27% with the Boston brace and 35% with the Milwaukee. Compliance with the Boston brace, however, was Brace treatment is not effective for a shorter duration than 18 months twiceasgoodaswiththeMilwaukeebrace(61vs.29%)[26].Bracetreatment must usually be carried out for a minimum of 18 months to have an effect on the vertebral wedging. In cases of rigid juvenile kyphosis, serial casting has been advocated by some authors [55, 68], but it is increasingly being abandoned because it is very inconvenient for the patient. Juvenile Kyphosis (Scheuermann’s Disease) Chapter 28 781 Table 6. Indications for surgery Absolute indications Relative indications neurological compromise progressive curves adolescents with curves >75 degrees painful curves cosmetic aspects Operative Treatment Indication for operation is not well defined Indications for surgery in juvenile kyphosis are still not well defined, due to the benign natural history of this condition and the lack of comparative long-term follow-up data after operation. Neurological compromise is the only absolute surgical indication The only absolute indication for surgery is a neurological compromise due to an increase in kyphosis, a disc protrusion or other intraspinal pathology with neurological compromise. Such complications are fortunately exceptional and would require spinal cord decompression through an anterior approach. Apart from these rare neurological complications, there is no evidence based indica- tion for surgery. Relative indications for surgical correction of the juvenile kyphosis are: kyphoticdeformityover75degrees rapidly progressive severe curve persistent pain unresponsive to non-operative care According to the literature, operative treatment should be considered in patients presenting with a kyphotic deformity of over 75 deg rees as severe curves tend to progress over time for biomechanical reasons. The assessment and the decision- making should not be based only on the Cobb angle, i.e. the degree of kyphosis. The localization of the apex of the deformity is of equal great importance. A low thoracic kyphosis with an apex close to the thoracolumbar junction has a more significant effect on the sagittal alignment of the spine than a deformity with the apex in the midthoracic area. Kyphosis over 75 degrees and/or persistent pain are generally accepted indications for operation Another indication for operation is significant pain not responding to conser- vative measures. The problem with pain as an indication, however, is that pain is impossible to measure objectively and the causal relation between pain and kyphosis is unclear. In addition, it has not been possible to establish a correlation so far between the amount of postoperative kyphosis correction and the patient’s clinical outcome [31, 56]. Surgerymustbeweighed against natural history and potential complications The surgical indications can only be looked at on a case-by-case basis because the natural history is generally benign and complications from surgery cannot be ruled out. Overtreatment must be avoided. According to Ascani and La Rosa [2], subjects who enjoy relatively good health and have a relatively benign prospect for adult life must not be “normalized” from a morphologic point of view. Preoperative Assessment The preoperative work-up will focus on the patient’s pain and/or cosmetic con- cerns, trying to identify the motivation of the patient. Preoperative assessment should include: assessment of hamstring tightness search for neurological findings pulmonary function tests (in severe deformities) 782 Section Spinal Deformities and Malformations radiographs (standing up, lateral, extension views) MRI clinical photograph (for outcome evaluation) Hamstring tightness in adolescent patients with thoracic hyperkyphosis was observedbyLambrinudi[34].Hebelievedthatitwouldbetheprimarycauseof the deformity. This theory, however, could not be proven. The importance of Tight hamstrings are a potential cause of postoperative sagittal decompensation tight hamstrings has recently been emphasized as a possible cause of sagittal decompensation after operation. Preoperative hamstring tightness predicts a limited lumbar and pelvic range of motion, i.e. a limited ability to adapt to curve correction. Therefore, patients with tight hamstrings have a significantly higher risk of postoperative sagittal imbalance [30]. MRI before surgery is recom- mended to rule out any cord compression, thoracic disc herniation, epidural cyst, possible spinal stenosis and concomitant spondylolysis (frequent). The literature has shown exceptional cases in various case reports of neurological complica- tions in Scheuermann’s kyphosis [6, 13, 16, 17, 38, 50, 74]. General Principles The operative approach is based on the analysis of the pathoanatomical features of the deformity. The hyperkyphosis is the result of marked structural changes in the bones and in the soft tissues of the affected area ( Table 7, Fig. 9a). For optimal correction of the deformity these obstacles of reduction have to be assessed and addressed individually. Several questions should be answered while planning the operative strategy: Does the curve need a n anterior release? Posterior surgery alone is sufficient if the rigidity of the anterior structures is not too severe, for instance in patients before growth arrest. Bradford et al. described significant loss of correction after posterior Harrington instru- mentation especially in patients with a kyphosis greater than 70 degrees despite postoperative casting [15]. They therefore proposed combined sur- Table 7. Structural changes in juvenile kyphosis Anterior column Posterior column wedged vertebral bodies disc space narrowing premature disc degeneration contracture of the anterior longitudinal ligament relative overgrowth of posterior elements (broad laminae, long spinous processes) reduced mobility of intervertebral joints narrow interlaminar spaces Figure 9. Surgical release Structural changes to be addressed during surgery: a, b anterior release: stiffness of intervertebral disc and anterior lon- gitudinal ligament; and c, d posterior release: overgrowth of the posterior elements. Juvenile Kyphosis (Scheuermann’s Disease) Chapter 28 783 gery in these severe cases. Lowe recommends posterior surgery alone only for immature patients. In his opinion adolescents and adults need combined surgery [40]. With modern third generation instrumentation systems, loss of correction after posterior surgery no longer seems to be a problem. Hos- man et al. did not see any differences in radiological or clinical outcome in a comparison of anterior surgery alone versus combined surgery. They con- cluded that anterior release is indicated only if bony bridges between the vertebrae are present or in kyphosis greater than 100 degrees [31]. Whatlevelshavetobeincludedinthefusion? Instrumentation should be carried out proximally from the upper end-ver- tebra of the kyphosis (usually T2, T3, or T4) down to the upper lumbar spine including the first lordotic disc space (usually L1, L2, or L3). Which technique of correction should be used? The correction principle preferred by most surgeons nowadays is cantilever correction performed using two or four rods, which results in a tension bend with posterior segmental compression. The vertebrae around the apex of the deformity are usually not instrumented. What is the target correction? In the individual patient, it is impossible to define the optimal degree of tho- racic kyphosis. The amount of correction should not exceed the ability of the adjacent mobile spinal segments to realign. The degree of hamstring tightness should be assessed and taken into consideration during planning. A kyphosis correction of more than 50% of its initial value should be The clinical outcome is not dependent on the amount of correction but rather on sagittal balance avoided as it bears the risk of imbalance or junctional kyphosis [31]. Correc- tionofthedeformitytothehigh“normal”kyphosisrangeof40–50degrees seems to be advisable in order to avoid postoperative imbalance [31]. There- fore, straighter is not necessarily better in the operative treatment of Scheu- ermann’s kyphosis ( Table 3). Operative Technique The first long-term results of Scheuermann’s kyphosis correction by posterior instrumentation using flexible Harrington compression rods and fusion were published by Bradford et al. in 1975 [15]. They reported on 22 patients with very satisfactory subjective outcome but a significant loss of correction, as seen also by other authors [25, 35]. Therefore, they changed their technique by adding anterior release and bone grafting to achieve circumferential fusion. Because of the flexibility of the instrumentation, postoperative cast immobilization from 9 to 12 months was deemed necessary. Using this technique in 24 patients, signifi- cant loss of correction (>10 degrees) was observed only in five patients outside the fusion area due to insufficient length of the instrumentation. Radiographi- cally, mean kyphosis improved from 77 degrees preoperatively to 47 degrees at follow-up. There were no neurological complications and no fatalities. Pulmo- nary embolus, atelectasis, and hemothorax occurred in two patients each, vascu- lar obstruction of the duodenum, deep wound infection, and pericardial effusion in one patient each. The clinical appearance was markedly improved in all patients. Twenty-three of the 24 patients experienced significant pain relief [12]. Using modern rigid posterior double-rod instrumentation allows for immediate Additional anterior release appears not to influence clinical outcome mobilization of the patients without a brace or cast. The rate of correction loss has diminished considerably, and in our time anterior surgery has become neces- sary only in extreme cases. Hosman et al., who used rigid posterior double-rod instrumentation, did not see any difference in outcome on comparing patients who had posterior surgery only with patients who had undergone additional anterior release [31]. 784 Section Spinal Deformities and Malformations . assess flexibility of the deformity. In the immature patient, the skeletal age and the remaining spinal growth are determined from a radiograph of the hand and wrist [24] and the pelvis (Risser. on MRI. 778 Section Spinal Deformities and Malformations Non-operative Treatment The general objectives of treatment are shown in Table 4. Table 4. General objectives of treatment to prevent. assessment of the risk of pro- gression and treatment decision-making. Magnetic Resonance Imaging In juvenile kyphosis, MRI is the imaging modality of choice to demonstrate: irregularity of the ossification wedge