Author's response to reviews

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1 Author's response to reviews Title: Scoliotic posture as the initial symptom in adolescents with lumbar disc herniation: its curve pattern and natural history after lumbar discectomy Authors: Zezhang Zhu Qinghua Zhao Bin Wang Yang Yu Bangping Qian Yitao Ding Yong Qiu Version: 3 Date: 27 August 2011 Author's response to reviews: see over

2 Authors Response Dear Editor, Thank you very much for your in which you sent me the comments on my paper with the reference MS: I m herewith submitting the modified version of my manuscript. In accordance with editorial requirements, some corresponding modifications in terms of title page, structure, figure titles, and tables are made in the revised manuscript. According to the reviewers comments, the following modifications have been made, which were also incorporated into the revised manuscript. Reviewer #1: In general I find this manuscript well written. It is an interesting topic and contributes clinical important/new information on scoliotic curve patterns associated with lumbar disc herniation in adolescents. My opinion is that it should be accepted for publication with minor revisions. However, I have some comments on the method used for measuring the Cobb angle of the lumbar curve (see below) and the authors should respond to these before publication. Response (R): We really appreciate your encouraging comments. According to your comments, some corresponding modifications are made and incorporated into the revised manuscript. 1) Question (Q): It is explained how lordosis and kyphosis were measured. However, it is not explained how scoliosis was measured. On Page 5, line 26 it is stated that: while the lower end vertebra was constant S1. My opinion is that S1 should not be considered the lower end vertebra. The S1 is not part of the scoliotic curve as it is fixed to the pelvis. The Cobb angle should be measured to the lower endplate of the lower lumbar end vertebra of the curve, not to S1. It should be clearly stated how scoliosis was measured. If it was measured down to S1 it should be stated. This way of measuring scoliosis is incorrect in my view. R: As a routine, Cobb method has been used to measure the amount of scoliotic curve in our center. On the basis of SRS terminology, a lumbosacral curve is a scoliosis that has its apex at L5 or below ( ). Considering the unique feature of sacrum that the vertebrae of the sacrum are fused, we feel it reasonable to choose S1 as the lower end vertebra for measuring Cobb angle in a lumbosacral curve, which is also referred to the guideline book, Radiographic Measurement Manual, by Spinal Deformity Study Group (Page 73 as shown below).

3 Some corresponding sentences are added to explain how scoliosis is measured in the revised manuscript (Line on Page 5). 2) Q: Page 5, line 4. The pain was scored from 0 (no pain) to 10 (severe) pain by visual analogue scale. The method used to score pain seems to be a numeric pain scale not visual analogue sale (which measures from 0 to 100 on a line without numbers). R: We agree with you. The term visual analogue scale has been changed to numeric pain scale in the revised manuscript (Line 24 on Page 6, Line 4 on Page 9 ). 3) Q: Page 5, line 8. Self-evaluation results of 19 patients were then evaluated using this instrument, and the ODI ranged from 11% to 62% (average, 21.4 %). I have problem to understand the meaning of this sentence, consider rewriting. It seems to me that it should be placed in Results, not in Materials and Methods? R: The sentence has been reorganized and placed in Results in the revised manuscript (Line 5-7 on Page 9). 4) Q: Page 5, line 26. while the lower end vertebra was constant S1 My opinion is that L5 should be considered the lower end vertebra. The S1 is not part of the scoliotic curve as it is fixed to the pelvis. The Cobb angle should be measured to the lower lumbar end vertebra, not to S1. R: Please see the response to question 1 above. 5) Q: Page 5, line 27. In my opinion The thoracic curve should be: A thoracic curve and the thoracolumbar curve should be: A thoracolumbar curve.

4 R: The thoracic curve has been changed to A thoracic curve and the thoracolumbar curve has been changed to a thoracolumbar curve in the revised manuscript (Line 9, 10 on Page 8). Reviewer #2: 1) Q: page 1 line 21: It is essential to know the durations of symptoms before patients were referred to your clinic. It is well known for adolescents with disc herniation to endure long conservative treatment before seeking surgery. R: The duration of symptoms at time of presentation ranged from 10 days to 15 months (mean, 4.3 months). A corresponding sentence is added to explicit this in the revised manuscript (Line 8-9 on Page 5). 2) Q: page 3 line 20 should read Risser sign 4 or more. Sign no less than 4 is confusing. R: no less than 4 has been changed to Risser sign 4 or more in the revised manuscript (Line 5 on Page 5). 3) Q: page 3 line 26 should read 2 levels of L4/L5 and L5/S1. L4-S1 is misleading. R: L4-S1 has been changed to 2 levels of L4-L5 and L5-S1 in the revised manuscript (Line 15, 18 on Page 5). 4) Q: page 4 line 19: Your reference is a paper discribing deformity in neuromuscular scoliosis. It might be proper to use SRS terminology or SOSORT terminology in defining deformity and deformity characteristics. R: With respect to SRS terminology, the recommended measurement of thoracic kyphosis from a lateral radiograph is the angle between the superior endplate of the highest measurable thoracic vertebra, usually T2 or T3, and the inferior endplate of T12. The recommended measurement of lumbar lordosis from a lateral radiograph is the angle between the superior endplate of L1 or T12 and the superior endplate of S1. In line with the SRS terminology, the superior end plate of T3 and inferior end plate of T12 were used to measure thoracic kyphosis, and the superior end plates of T12 and S1 were used to measure lumbar lordosis in our series(line on Page 4 in the primary manuscript). This method of sagittal measurement has also been widely used in previous studies (Bernhardt M, et al. Segmental analysis of the sagittal plane alignment of the normal thoracic and lumbar spines and thoracolumbar junction.spine 1989;14:717 21; Boseker EH, et al. Determination of normal thoracickyphosis: a roentgenographic study of 121 normal children. J Pediatr Orthop 2000;20:796 8; Vedantam R, et al. Comparison of standing sagittal spinal alignment in asymptomatic adolescents and adults. Spine 1998;23: 211 5). On the basis of the normative data for sagittal alignment measured using the same levels in children and adolescents reported in the above-mentioned literature, Spiegel et al (Ref. 15) defined the abnormal sagittal alignment in children and adolescents (i.e.

5 the abnormal lumbar alignment as the value more than 1 standard deviation of the mean) to analyze the thoracic and lumbar profile in patients with Chiari malformation and/or syringomyelia. Taking into consideration the fact that the normative data for sagittal alignment in children and adolescents are applicable to not just neuromuscular scoliosis, but other types of scoliosis, the sgaittal alignment in our series was evaluated according to the definition by Spiegel et al. 5) Q: Page 5 line 2: correct lumbosacral R: The corresponding correction has been made in the revised manuscript (Line 21 on Page 6). 6) Q: Page 5 from line 5 should be in a seperate heading: statistical analysis. R: The corresponding change has been made in the revised manuscript (Line 28 on Page 6). 7) Q: page 7 line 9: Are there any relationships between symptoms, curve angle and sagittal profile? R: For the 2 patients (No. 12 and 21) with a residual lumbosacral curve 20 at the last follow-up, no associations between pain, residual curve angle and sagittal profile were noticed since both of them were pain-free and the improvement of lumbar lordosis was well maintained during follow-up. A corresponding sentence is added to explicit this in the revised manuscript (Line on Page 7). 8) Q: page 7: Discussion: Should try to separate structural scoliosis from non structural scoliosis. R: Some modifications are made to further emphasize the differentiation between structural and non-structural scoliosis (Line on Page 5, Line on Page 11). 9) Q: page 8 line 4. Those 4 patients misdiagnosed as AIS and treated with brace, what is the characteristics of their curves. If they were left sided thoracic, one will have expected an MRI evaluation to rule out intraspinal patology like disc herniation. How long were they treated before referral to your clinic? R: The curve patterns of those 4 patients misdiagnosed as AIS and treated with brace were shown in Table 2 (Patients No. 6, 13, 14, and 24). Bracing treatment was continued for 6-15 months before referral to our clinic. Some corresponding modifications are made to explicit this in the revised manuscript (Line 7 on Page 5, Line 10 on Page 11). All of them did not receive an MRI evaluation at local hospitals, which also demonstrated the necessity for us to explore the curve pattern of scoliosis in adolescents with lumbar disc herniation. 10) Q: Page 9 line Lack of assesement of curve flexibility on lateral bending films is a serious omission in a paper like this. Flexibility evaluation could have established the non-structurality of the curves. The Forward Bending Test has also been ommitted in the clinical evaluation of the curves.

6 R: Curve flexibility has been considered in the management of scoliosis, especially in surgical planning for spinal deformity as a useful predictor of expected surgical correction. We totally agree that side-bending films have been used by the routine to assess the flexibility of the scoliotic curve. As for the patients in the current study, most of them had low back pain or buttock pain (shown in Table 1 in the primary manuscript). Hence, the side-bending films might not be practical for those patients, which have been addressed in the primary manuscript (Line on Page 9). Additionally, the surgical intervention was performed for the lumbar disc herniation rather than scoliosis in our series although the scoliotic posture was the initial symptom. Some corresponding modifications are made to further emphasize the importance of flexibility evaluation in the revised manuscript (Line on Page 12). We totally agree that an Adams forward bend test can usually differentiate between structural and posture scoliosis. Actually, this test is a routine physical exam in our scoliosis clinic for scoliosis screening. In the current study, 73% (19/26) had limitation of lumbar spine movement (shown in Table 1 in the primary manuscript). Hence, the Adams forward bend test might not be practical for those patients having restriction of lumbar motion. As for the other 7 patients without restriction of forward flexion, the Adams forward bend test was performed, showing a disappearing of the back deformity in all of the 7 patients. Some corresponding modifications are made to explicit this in the revised manuscript (Line on Page 5, Line on Page 11). 11) Q: Page 11 line 22. How early to you recommend discectomy to be performed? R: In our series, a standard posterior micro-discectomy was performed on those patients following failure to respond to conservative management for 7-12 weeks. A corresponding sentence is added to explicit this in the revised manuscript (Line 5-6 on Page 15). The modifications mentioned above were highlighted in light gray in the revised manuscript. We would like to thank you and the reviewer for the time and effort that go into the review of this paper. Yours sincerely, Yong Qiu