Cervical spine alignment in the pediatric population: a radiographic normative study of 150 asymptomatic patients

Purpose

To describe the normal cervical sagittal alignment of the pediatric spine in a normal population and to identify the changes during growth period.

Methods

We randomly selected in PACS database 150 full-spine standing views. Exclusion criteria were: age >18 years, spinal deformity and any disease affecting the spine (medical charts reviewing). For cervical alignment we measured: OC-angle according to Mc Gregor, C1C7 angle, upper cervical angle, inferior cervical angle and C7 tilt. Spino pelvic parameters were analyzed: T1 tilt, thoracic kyphosis, lumbar lordosis, pelvic incidence, sacral slope and pelvic tilt. We compared two age subgroups (juvenile and adolescent). Differences between age groups and gender were tested using Student’s t test. Correlations between sagittal spinal parameters were evaluated using Pearson’s test.

Results

Cervical spine shape was correlated to cranio cervical orientation to maintain horizontal gaze (r = 0.60) and to thoracic kyphosis (r = ?0.46). Cervical spine alignment was significantly different between the two age groups except for the global C1C7 cervical lordosis, which remained stable. A significant gender difference was found for all the cervical sagittal angles (p < 0.01) whereas no differences were demonstrated for the spino pelvic parameters, except the lumbar lordosis (p = 0.047).

Conclusions

This study is the first to report the cervical spinal alignment in a normal pediatric Caucasian population. Even though cervical lordosis is the common shape, our results showed variability in cervical sagittal alignment. Cervical spine is a junctional area that adjusts its alignment to the head position and to the underlying spinal alignment.     

Evaluation of a new type of titanium mesh cage versus the traditional titanium mesh cage for single-level, anterior cervical corpectomy and fusion

Study design

A retrospective review of prospectively collected data in an academic institution.

Objective

To evaluate the safety and efficacy of a new type of titanium mesh cage (TMC) in single-level, anterior cervical corpectomy and fusion (ACCF).

Methods

Fifty-eight patients consecutive with cervical spondylotic myelopathy (CSM) from cervical degenerative spondylosis and isolated ossification of the posterior longitudinal ligament were treated with a single-level ACCF using either a new type of TMC (28 patients, group A) or the traditional TMC (30 patients, group B). We evaluated the patients for TMC subsidence, cervical lordosis (C2–C7 Cobb and Cobb of fused segments) and fusion status for a minimum of 30 months postoperatively based on spine radiographs. In addition, neurologic outcomes were evaluated using the Japanese Orthopedic Association (JOA) scores. Neck pain was evaluated using a 10-point visual analog scale (VAS).

Results

The loss of height of the fused segments was less for group A than for group B (0.8 ± 0.3 vs. 2.8 ± 0.4 mm) (p < 0.01); also, there was a lower rate of severe subsidence (≥3 mm) in group A (4 %, 1/28) than in group B (17 %, 5/30) (p < 0.01). There were no differences in the C2–C7 Cobb and Cobb of fused segments between the groups preoperatively or at final follow-up (p > 0.05), but the Cobb of fused segments immediately postoperative were significantly less for group B than for group A (p < 0.01). All patients, however, had successful fusion (100 %, each). Both groups had marked improvement in the JOA score after operation (p < 0.01), with no significant differences in the JOA recovery ratio (p > 0.05). The postoperative VAS neck pain scores for group A were significantly less than that for group B (p < 0.05); severe subsidence was correlated with neck pain.

Conclusions

The new type of TMC provides comparable clinical results and fusion rates with the traditional TMC for patients undergoing single-level corpectomy. The new design TMC decreases postoperative subsidence (compared to the traditional TMC); the unique design of the new type of TMC matches the vertebral endplate morphology which appears to decrease the severity of subsidence-related neck pain in follow-up.     

Reciprocal changes in cervical spine alignment after corrective thoracolumbar deformity surgery

Purpose

To identify changes in cervical alignment parameters following surgical correction of thoracolumbar deformity and then assess the preoperative parameters which induce changes in cervical alignment following corrective thoracolumbar deformity surgery.

Methods

A retrospective study of 49 patients treated for thoracolumbar deformity with preoperative planning of an acceptably aligned coronal and sagittal plane in each case. We compared cervical spine parameters in two distinct low [preoperative C7 sagittal vertical axis (SVA) ≤6 cm] and high (preoperative C7 SVA ≥9 cm) C7 SVA groups. Multilinear regression analysis was performed and revealed the relationship between postoperative cervical lordosis and preoperative spinopelvic parameters and surgical plans.

Results

In the lower C7 SVA group, cervical lordosis was significantly increased after thoracic/lumbar deformity correction (p < 0.01). In contrast, the high C7 SVA group showed decreased cervical lordosis postoperatively (p < 0.01). Multilinear regression analysis demonstrated the preoperative parameters (preoperative C2–7 angle, T1 slope, surgical plan for PT and C7 SVA), which determine the postoperative cervical lordosis.

Conclusion

In spinal deformity procedures, preoperative spinal alignment parameters, and surgical plans could affect postoperative cervical spine alignment.     

Alterations in axial curvature of the cervical spine with a combination of rotation and extension in the conventional anterior cervical approach

Purpose

Alterations of three-dimensional cervical curvature in conventional anterior cervical approach position are not well understood. The purpose of this study was to evaluate alignment changes of the cervical spine in the position. In addition, simulated corpectomy was evaluated with regard to sufficiency of decompression and perforation of the vertebral artery canal.

Methods

Fifty patients with cervical spinal disorders participated. Cervical CT scanning was performed in the neutral and supine position (N-position) and in extension and right rotation simulating the conventional anterior approach position (ER-position). Rotation at each vertebral level was measured. With simulation of anterior corpectomy in a vertical direction with a width of 17 mm, decompression width at the posterior wall of the vertebrae and the distance from each foramen of the vertebral artery (VA) were measured.

Results

In the ER-position, the cervical spine was rotated rightward by 37.2° ± 6.2° between the occipital bone and C7. While the cervical spine was mainly rotated at C1/2, the subaxial vertebrae were also rotated by several degrees. Due to the subaxial rotation, the simulated corpectomy resulted in smaller decompression width on the left side and came closer to the VA canal on the right side.

Conclusions

In the ER-position, the degrees of right rotation of subaxial vertebrae were small but significant. Therefore, preoperative understanding of this alteration of cervical alignment is essential for performing safe and sufficient anterior corpectomy of the cervical spine.     

Posterolateral versus circumferential instrumented fusion for monosegmental lumbar degenerative disc disease using an expandable cage

Background

Theoretically, 360° instrumented fusion has been considered to offer better radiological correction than PLF. Despite numerous publications, this correlation is still weak with several controversies in the relative literature.

Purpose

This prospective randomized study was designed to compare the radiological segmental results, complications and outcome of 360° instrumented fusion with the use of a single diagonal expandable PLIF device versus posterolateral pedicle screw fixation in monosegmental lumbar DDD and to show that the use of an novel expandable cage is associated with low PLIF-related complication rate compared to conventional cages reported previously.

Study design

Prospective randomized controlled clinical and radiological study.

Patient sample

Adults who suffered from monosegmental DDD were eligible for enrolment in this trial. We randomly assigned 150 patients to receive either 360° instrumented fusion (group A) with expandable cage or PLF (group B).

Outcome measures

Differences between the two groups regarding clinical parameters and radiographic sagittal measurements after 36?months of follow-up.

Methods

The record included global [T12-S1 lordosis, sagittal global spinal balance (SB) (C7-mid-femoral axis)] and segmental [segmental disc wedging (SDW), anterior (ADHr) and posterior (PDHr) disc height ratio] radiological measurements at the instrumented segment. Additionally, clinical outcome was evaluated with VAS, SF-36 (Physical function and Bodily Pain) and ODI questionnaires. Fusion was evaluated with the use of Christiansen method.

Results

In 73 and 72 participants of group A and B, respectively, who completed follow-up to 36?months, there were no differences with respect to the rate of improvement in SF-36, ODI and VAS scores. However, in the spines of group A, there was a significant increase in anterior disc height ratio (P?=?0.0057), posterior disc height (P?=?0.016) and segmental disc wedging (P?=?0.00021) without subsequent loss of correction. Fusion rate was radiologically shown in 94.5% and 87% spines of group A and B, respectively (P?>?0.2). Four and 9 spines in group A and B, respectively, showed non-union at the final observation.

Conclusions

Our findings suggest that 360° fusion offers better sagittal radiological restoration associated with circumferential fusion. However, this difference seemed not to have any medium-term clinical impact. The use of expandable cage was associated with low PLIF-related complications compared to conventional cages.     

Reduction in range of cervical motion on serial long-term follow-up in patients undergoing oblique corpectomy for cervical spondylotic myelopathy

Purpose

To determine whether motion preservation following oblique cervical corpectomy (OCC) for cervical spondylotic myelopathy (CSM) persists with serial follow-up.

Methods

We included 28 patients with preoperative and at least two serial follow-up neutral and dynamic cervical spine radiographs who underwent OCC for CSM. Patients with an ossified posterior longitudinal ligament (OPLL) were excluded. Changes in sagittal curvature, segmental and whole spine range of motion (ROM) were measured. Nathan’s system graded anterior osteophyte formation. Neurological function was measured by Nurick’s grade and modified Japanese Orthopedic Association (JOA) scores.

Results

The majority (23 patients) had a single or 2-level corpectomy. The average duration of follow-up was 45 months. The Nurick’s grade and the JOA scores showed statistically significant improvements after surgery (p < 0.001). 17 % of patients with preoperative lordotic spines had a loss of lordosis at last follow-up, but with no clinical worsening. 77 % of the whole spine ROM and 62 % of segmental ROM was preserved at last follow-up. The whole spine and segmental ROM decreased by 11.2° and 10.9°, respectively (p ≤ 0.001). Patients with a greater range of segmental movement preoperatively had a statistically greater range of movement at follow-up. The analysis of serial radiographs indicated that the range of movement of the whole spine and the range of movement at the segmental spine levels significantly reduced during the follow-up period. Nathan’s grade showed increase in osteophytosis in more than two-thirds of the patients (p ≤ 0.01). The whole spine range of movement at follow-up significantly correlated with Nathan’s grade.

Conclusions

Although the OCC preserves segmental and whole spine ROM, serial measurements show a progressive decrease in ROM albeit without clinical worsening. The reduction in this ROM is probably related to degenerative ossification of spinal ligaments.     

Comparison of anterior cervical fusion after two-level discectomy or single-level corpectomy: sagittal alignment,cervical lordosis,graft collapse,and adjacent-level ossification

Background contextSingle-level corpectomy and two-level discectomy with anterior cervical plating have been reported to have comparable fusion and complication rates. However, there are few large series that have compared the two for sagittal alignment, cervical lordosis, graft subsidence, and adjacent-level ossification.PurposeTo determine the differences between these two procedures for patients with two-level spondylosis by comparing the pre- and postoperative radiographic data.Study designRetrospective review of prospectively collected data in an academic institution.Patient sampleFifty-two with a single-level corpectomy and 45 with a two-level anterior cervical discectomy and fusion (ACDF).Outcome measuresPre- and postoperative radiographic data for sagittal alignment, cervical lordosis, subsidence, and adjacent-level ossification.MethodsWe retrospectively reviewed the lateral cervical radiographs of patients who had a solid fusion after a single-level cervical corpectomy or a two-level ACDF for the treatment of a degenerative cervical spondylosis by a surgeon at an academic institution. The choice of the operation was dependent on the presence or absence of retrovertebral compression. All patients underwent anterior cervical fusion using fibula strut allograft and variable-angle screw-plate fixation. None had had prior cervical spine surgery. Twenty-five were excluded because of inadequate radiographs and follow-up. There were 52 with a single-level corpectomy and 45 with a two-level ACDF. The following were analyzed: 1) sagittal alignment (modified method of Toyama); 2) cervical lordosis measured by Cobb angles of fusion constructs (fusion Cobb) and C2–C7 (C2–C7 Cobb); 3) graft collapse determined by the subsidence of anterior/posterior body height of fused segments (anterior/posterior subsidence) and the cranial/caudal plate-to-disc distances (cranial/caudal subsidence), and the difference between anterior and posterior body height for the fused levels (anteroposterior [AP] difference); and 4) the severity of ossification at two adjacent levels.ResultsThe mean durations of follow-up were 23.3±6.6 (corpectomy) and 25.7±6.2 (ACDF) months, range 12 to 45 months. There were no significant differences between the two groups in sagittal alignment, cervical lordosis, graft collapse, and adjacent-level ossification. Graft subsidence and loss of cervical lordosis occurred significantly more during the first 6 weeks after surgery (all measurements, p<.0001) than after 6 weeks, with no significant difference between the two groups. Posterior and caudal end plate subsidence significantly progressed after 6 weeks in Group 1 (p=.04, p=.02). The final follow-up Cobb angle positively correlated with preoperative and immediate postoperative Cobb angles (r=0.437, p<.0001; r=0.727, p<.0001), caudal subsidence (r=0.270, p=.008), and the final AP difference (r=0.915, p<.0001) but did not correlate with surgery level, preoperative and final sagittal alignments, anterior/posterior subsidence, and cranial subsidence. Anterior/posterior subsidence was significantly more strongly related with caudal subsidence (r=0.607, p<.0001; r=0.424, p<.0001) than cranial (r=0.277, p=.007; r=0.211, p=.040) but did not correlate with pre- and postoperative fusion Cobb, and preoperative and the last sagittal alignments.ConclusionsOur data suggest that the two procedures yield comparable results in terms of sagittal alignment, cervical lordosis, graft subsidence, and adjacent-level ossification. Graft subsidence and loss of cervical lordosis appeared to occur mainly during the first 6 weeks after surgery. Single-level corpectomy and fusion continued to subside at the posterior portion of caudal end plate even after 6 weeks. On the other hand, graft subsidence did not correlate with preoperative and final postoperative sagittal alignments.     

Influence of transforaminal lumbar interbody fusion procedures on spinal and pelvic parameters of sagittal balance

Introduction

Restitution of sagittal balance is important after lumbar fusion, because it improves fusion rate and may reduce the rate of adjacent segment disease. The purpose of the present study was to describe the impact of transforaminal lumbar interbody fusion (TLIF) procedures on pelvic and spinal parameters and sagittal balance.

Materials and methods

Forty-five patients who had single-level TLIF were included in this study. Pelvic and spinal radiological parameters of sagittal balance were measured preoperatively, postoperatively and at latest follow-up.

Results

Age at surgery averaged 58.4 (±9.6) years. Mean follow-up was 35.1 months (±4.1). Twenty-nine percent of the patients exhibited anterior imbalance preoperatively, with high pelvic tilt (17.6° ± 7.9°). Of the 32 (71%) patients well balanced before the procedure, 22 (70%) had a large pelvic tilt (>20°), due to retroversion of the pelvis as an adaptive response to the loss of lordosis. Three dural tears (7%) were reported intraoperatively. Interbody cages were more posterior than intended in 27% of the cases. Disc height and lumbar lordosis at fusion level significantly increased postoperatively (p < 0.05 and p < 0.001). Pelvic tilt was significantly reduced (p < 0.01) postoperatively, whereas the global sagittal balance was not significantly modified (p = 0.07).

Conclusion

Single-level circumferential fusion helps patients reducing their pelvic compensation, but the amount of correction does not allow for complete correction of sagittal imbalance.     

Clinical outcomes of unstable thoracolumbar junction burst fractures: combined posterior short-segment correction followed by thoracoscopic corpectomy and fusion

Background

There is significant controversy surrounding the ideal management of thoracolumbar burst fractures. While several treatment and management algorithms have been proposed, the ideal treatment strategy for these fractures remains unsettled. The authors review their experience with short-segment posterior fusion followed by anterior thoracoscopic corpectomy for the treatment of unstable thoracolumbar burst fractures.

Methods

We identified all patients treated by a single surgeon at our institution from 2002 to 2009 with short-segment posterior fusion followed by anterior thoracoscopic corpectomy for unstable thoracolumbar junction burst fractures. Demographic data, mechanism of injury, classification of fracture, Cobb angle, American Spinal Injury Association score, associated injuries, tobacco use, follow-up duration, and radiographic studies were all collected. Outcomes were assessed for fracture alignment (preoperative, postoperative, and long-term follow-up kyphosis), rate of fusion, neurological outcome, and treatment complications.

Results

Thirty-two patients with burst fracture of the thoracolumbar junction defined as T10 to L1 were included. At a mean follow-up of 20.4 months, 90 % of patients had demonstrated radiographic evidence of fusion and 91 % retained the correction of their kyphotic deformity. There were three complications in the series.

Conclusions

Short-segment posterior fusion with thoracoscopic anterior corpectomy represents an alternative to traditional open treatment of thoracolumbar burst fractures. A thoracoscopic approach allows for a short-segment posterior fusion, reducing the loss of adjacent motion segments, minimizes morbidity associated with traditional open anterior approaches, allows for anterior and posterior column stabilization, and is associated with a high rate of bony fusion.     

Cervical sagittal alignment in adolescent idiopathic scoliosis patients (Lenke type 1–6)

Objective

We collected the radiographic and clinical data of 129 AIS patients (Lenke type 1–6) to analyze the characteristics of cervical sagittal alignment in adolescent idiopathic scoliosis patients and the correlations between cervical sagittal alignment and global sagittal alignment, and clinical symptoms.

Analysis of the cervical spine sagittal alignment in young idiopathic scoliosis: a morphological classification of 120 cases

Purpose

To analyze the relationship between the cervical spine and global spinal-pelvic alignment in young patients with idiopathic scoliosis based on a morphological classification, and to postulate the hypothesis that cervical kyphosis is a part of cervico-thoracic kyphosis in them.

Methods

120 young patients with idiopathic scoliosis were recruited retrospectively between 2006 and 2011. The following values were measured and calculated: cervical angles (CA), cervico-thoracic angles (CTA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), spinal sacral angle (SSA), hip to C7/hip to sacrum, thoracic kyphosis (TK), lumbar lordosis (LL), Roussouly sagittal classification, Lenke Type Curve and Lumbar Modifier. The cervical curves were classified as lordosis, straight, sigmoid and kyphosis. They were categorized into four groups as cervical non-kyphosis group (CNK Group), cervical kyphosis group (CK Group), cervical-middle-thoracic kyphosis group (CMTK Group), and cervical-lower-thoracic kyphosis group (CLTK Group) according to their morphological characters of sagittal alignments. All parameters were compared and analyzed among groups.

Results

The incidence of cervical kyphosis was 40 % (48/120). The CA and the CTA were in significant correlation (r = 0.854, P = 0.00). The cervical spine alignments were revealed to be significantly different among groups (r = 85.04, P = 0.00). Significant differences among groups in CA, CTA and TK were also detected. A strong correlation between the group type and Lenke Lumbar Modifier was still seen (P < 0.05). Fisher’s exact test revealed that the individual vertebral body kyphosis and wedging were directly related to the overall cervical kyphosis (P = 0.00, respectively).

Conclusion

The cervical kyphosis is correlated with global sagittal alignment, and is a part of cervico-thoracic sagittal deformity in young patients with idiopathic scoliosis. Despite the deformity in cervical alignment, the global spine could still be well-balanced with spontaneous adjustment. The correlation between our grouping based on the morphological characteristics of the sagittal alignments and Lenke Lumbar Modifier suggests that the coupled motion principle be appropriate to explain the modifications both in coronal and sagittal planes.     

Body posture and backpack loading: an upright magnetic resonance imaging study of the adult lumbar spine

Purpose

Axial loading of the spine while supine, simulating upright posture, decreases intervertebral disc (IVD) height and lumbar length and increases lumbar lordosis. The purpose of this study is to measure the adult lumbar spine’s response to upright posture and a backpack load using upright magnetic resonance imaging (MRI). We hypothesize that higher spinal loads, while upright and with a backpack, will compress lumbar length and IVD height as well as decrease lumbar lordosis.

Methods

Six volunteers (45 ± 6 years) underwent 0.6 T MRI scans of the lumbar spine while supine, upright, and upright with a 10 % body weight (BW) backpack. Main outcomes were IVD height, lumbar spinal length (distance between anterior–superior corners of L1 and S1), and lumbar lordosis (Cobb angle between the superior endplates of L1 and S1).

Results

The 10 % BW load significantly compressed the L4–L5 and L5–S1 IVDs relative to supine (p < 0.05). The upright and upright plus 10 % BW backpack conditions significantly compressed the anterior height of L5–S1 relative to supine (p < 0.05), but did not significantly change the lumbar length or lumbar lordosis.

Conclusions

The L4–L5 and L5–S1 IVDs compress, particularly anteriorly, when transitioning from supine to upright position with a 10 % BW backpack. This study is the first radiographic analysis to describe the adult lumbar spine wearing common backpack loads. The novel upright MRI protocol described allows for functional, in vivo, loaded measurements of the spine that enables the study of spinal biomechanics and therapeutic interventions.     

Sagittal geometry of the middle and lower cervical endplates

Purpose

Construct subsidence is a relatively common complication following anterior cervical fusion. Its occurrence has been revealed to be closely related to endplate-implant contact interface. But current literature focusing on the anatomy of cervical endplate is very scarce. The purpose of this morphometric study was to analyse the sagittal geometry, especially the concavity and slope, of vertebral endplates from C3 to C7 by employing data from CT scans.

Methods

Reformatted CT scans of 97 individuals were analyzed and endplate concavity depth, endplate concavity apex location, as well as endplate slope were measured in midsagittal plane. Those specific parameters were compared among different age and gender groups. Meanwhile, comparison between superior and inferior endplate of each vertebra was also performed.

Results

Age and gender did not influence endplate concavity depth, endplate concavity apex location, or endplate slope significantly (P > 0.05). Endplate concavity depths of superior endplates (range 0.9–1.2 mm) were significantly smaller than those of inferior endplates (range 2.1–2.7 mm). Endplate concavity apex was always located in the posterior half of the endplate, with the superior one ranged from 56 to 67 % and the inferior one 52 to 57 %. Average endplate slopes of superior endplates were between 4.5° and 9.0°, and average inferior endplate slopes ranged from 4.5° to 7.5°. Among all measured segments, C5 had the largest endplate slope values, while C7 the least.

Conclusions

Superior endplate is more flat than its inferior counterpart in middle and lower cervical spine, and the concavity apex is always located in the posterior half of the endplate. Endplate slope is correlated with cervical curvature, greater slope implying more significant lordosis. These sagittal endplate geometrical parameters should be taken into consideration when investigating implant subsidence following anterior cervical fusion.     

Reciprocal sagittal alignment changes after posterior fusion in the setting of adolescent idiopathic scoliosis

Purpose

Surgical adolescent idiopathic scoliosis (AIS) management can be associated with loss of thoracic kyphosis and a secondary loss of lumbar lordosis leading to iatrogenic flatback. Such conditions are associated with poorer clinical outcomes during adulthood. The aim of this study was to evaluate sagittal plane reciprocal changes after posterior spinal fusion in the setting of AIS.

Methods

Thirty consecutive adolescents (mean age 14.6 years) with AIS Lenke 1, 2 or 3 were included in this retrospective study with 2 year follow-up. Full-spine standing coronal and lateral radiographs were obtained preoperatively, at 3 and 24 months postoperatively. Coronal Cobb angle, thoracic kyphosis (TK) and lumbar lordosis (LL) were measured. Surgical procedure was similar in all the cases, with use of pedicular screws between T11 and the lowest instrumented vertebra (≥L2), sublaminar hooks applied in compression at the upper thoracic level and sub-laminar bands and clamps in the concavity of the deformity. Statistical analysis was done using t test and Pearson correlation coefficient.

Results

Between preoperative and last follow-up evaluations a significant reduction of Cobb angle was observed (53.6° vs. 17.2°, p < 0.001). A significant improvement of the instrumented thoracic kyphosis, TK (19.7° vs. 26.2°, p < 0.005) was noted, without difference between 3 and 24 months postoperatively. An improvement in lumbar lordosis, LL (43.9° vs. 47.3°, p = 0.009) was also noted but occurred after the third postoperative month. A significant correlation was found between TK correction and improvement of LL (R = 0.382, p = 0.037), without correlation between these reciprocal changes and the amount of coronal correction.

Conclusion

Results from this study reveal that sagittal reciprocal changes occur after posterior fusion when TK is restored. These changes are visible after 3 months postoperatively, corresponding to a progressive adaptation of patient posture to the surgically induced alignment. These changes are not correlated with coronal plane correction of the deformity. In the setting of AIS, TK restoration is a critical goal and permits favorable postural adaptation. Further studies will include pelvic parameters and clinical scores in order to evaluate the impact of the noted reciprocal changes.     

Adult spinal deformity: effectiveness of interbody lordotic cages to restore disc angle and spino-pelvic parameters through completely mini-invasive trans-psoas and hybrid approach

Purpose

The aim of the study is to assess and quantify the effectiveness of interbody lordotic cages applied by trans-psoas approach to improve radiographic parameters, showing the differences between completely mini-invasive and hybrid approach.

Methods

We collected data of 65 patients affected by degenerative lumbar deformity/diseases and underwent mini-invasive lateral interbody fusion followed by percutaneous (group A, completely mini-invasive) or open (group B, hybrid) posterior instrumentation. A subgroup underwent anterior column realignment (ACR). We assessed statistical differences in preoperative and postoperative (at least 6-month) coronal and sagittal parameters, and disc angle (DA) at each level of cage application.

Results

107 lordotic cages were implanted. Group B had the most significant mean changes, especially in coronal Cobb angle, sagittal vertical axis, lumbar lordosis (LL), pelvic incidence-LL mismatch and DA. Concerning DA, at each level of lordotic cage application, in group A changed from ?2.9° preop to ?6.5° postop (p = 0.01); in group B, DA changed from ?2.6° to ?9.5° (p = 0.002) and from +1° to ?13.2° in patients underwent ACR.

Conclusions

Minimally invasive lateral lumbar interbody fusion is an effective technique in improving sagittal parameters. When combined with posterior open approach and/or application of ACR procedure greater corrections are possible.

     

Comparison of titanium and polyetheretherketone (PEEK) cages in the surgical treatment of multilevel cervical spondylotic myelopathy: a prospective, randomized, control study with over 7-year follow-up

Purpose

Anterior cervical discectomy and fusion (ACDF) with titanium- or polyetheretherketone (PEEK)-cage reconstruction is widely used in the treatment of cervical spondylotic myelopathy (CSM). This study was to compare outcomes of titanium and PEEK cages in the treatment of multilevel CSM.

Methods

Between November 2002 and December 2004, a total of 80 patients with 3-level CSM were randomized in a 1:1 ratio to titanium group and PEEK group. The overall follow-up period of the patients ranged from 86 to 116 months (average 99.7 months). Clinical and radiological results were compared between titanium group and PEEK group.

Results

At the final follow-up, the clinical outcomes including JOA score, NDI score, and the excellent and good rates of clinical outcomes in the PEEK group were better than those in the titanium group. More loss of the Cobb angles and the intervertebral height was observed in the titanium group, resulting in the radiological parameters in the titanium group becoming inferior to the PEEK group at the final follow-up. Cage subsidence rates were 34.5 and 5.4 % in the titanium and PEEK groups, respectively. Fusion was observed in all patients of two groups at the final follow-up. Two patients presented with cage dislocation without clinical symptoms in the titanium group.

Conclusions

In surgical treatment of multilevel CSM, PEEK cage is superior to titanium cage in maintenance of intervertebral height and cervical lordosis, resulting in better clinical outcomes in the long-term follow-up.     

Annual changes in radiographic indices of the spine in cerebral palsy patients

Purpose

We estimated the annual changes in radiographic indices of the spine in cerebral palsy (CP) patients and analyzed the factors that influence its progression rate.

Methods

We included CP patients who had undergone whole-spine radiography more than twice and were followed for at least 1 year. The scoliosis Cobb angle, coronal balance, apical vertebral translation, apical rotation, and pelvic obliquity were measured on anteroposterior (AP) radiographs; thoracic kyphosis and lumbar lordosis angles, and sagittal balance was measured on lateral radiographs; and migration percentage was measured on AP hip radiographs to determine hip instability. For each gross motor function classification system (GMFCS) level, the Cobb angles, apical vertebral translation, coronal and sagittal balance, and pelvic obliquity were adjusted by multiple factors with a linear mixed model.

Results

A total of 184 patients (774 radiographs) were included in this study. There was no significant annual change in scoliosis Cobb, thoracic kyphosis, and lumbar lordosis angles in the GMFCS level I–II and III groups. In the GMFCS level IV–V group, there was an annual increase of 3.4° in the scoliosis Cobb angle (p = 0.020). The thoracic kyphosis angle increased by 2.2° (p = 0.018) annually in the GMFCS level IV–V group. Apical vertebral translation increased by 5.4 mm (p = 0.029) annually in the GMFCS level IV–V group. Progression of coronal and sagittal balance and pelvic obliquity with aging were not statistically significant. Sex, hip instability, hip surgery, and triradiate cartilage did not affect the progression of scoliosis and the balance of the spine and pelvis.

Conclusions

The scoliosis Cobb angle, thoracic kyphosis angle, and apical vertebral translation in the GMFCS level IV–V CP patients progressed with age. These findings can predict radiographic progression of scoliosis in CP patients.

     

3D analysis of brace treatment in idiopathic scoliosis

Purpose

We have evaluated the effect of bracing in scoliosis on coronal alignment in a cohort of patients. Current literature has not described the specific effect of bracing on the 3D shape of the scoliotic curves. The purpose of this study was to analyze the variability of the 3D effect of bracing on idiopathic scoliosis.

Materials and methods

The spines of 30 patients with adolescent idiopathic scoliosis were reconstructed using biplanar stereoradiography with and without the brace. The Cobb angle, sagittal and pelvic parameters and transverse plane parameters were calculated. The variability and the mean values of each parameter, with and without a brace, were analyzed and compared using a student t test.

Results

The Cobb angle improved in 50 % of patients but remained unchanged in 50 % cases. In 90 % of the cases lordosis was decreased. The thoracic kyphosis was decreased in 26 % cases, unchanged in 57 % of cases and increased in 17 % cases. The AVR was improved (>5°) in 26 % cases, worsened in 23 % and unchanged in 50 %. Only the differences of Cobb angle and the lordosis were statistically significant.

Conclusions

Global statistics of this study concur with the literature. The Cobb angle was significantly improved. It also showed a significant hypolordotic effect. However, the results showed a high variability of the brace treatment effect in almost every parameter. Analysis of this variability by means of 3D reconstructions instead of global statistics should help characterize the mechanisms of correction of brace treatment.     

Anterior surgical options for the treatment of cervical spondylotic myelopathy in a long-term follow-up study

Objective

To provide a basis for the choice of anterior surgery procedures in the treatment of cervical spondylotic myelopathy (CSM) through long-term follow-up.

Methods

A consecutive series of 89 patients with CSM having complete follow-up data were analyzed retrospectively. All patients were treated with anterior cervical discectomy and fusion (ACDF), and anterior cervical corpectomy and fusion (ACCF) from July 2000 to June 2007. The lesions were located in one segment (n = 25), two segments (n = 56), and three segments (n = 8). Preoperative and postoperative, the C2–C7 angle, cervical intervertebral height, radiographic fusion status, result of the adjacent segment degeneration, the Japanese Orthopaedic Association (JOA), and the Short Form 36-item (SF36) questionnaire scores were used to evaluate the efficacy of the surgery.

Results

According to the different compression conditions of the 89 cases, different anterior operation procedures were chosen and satisfactory results were achieved, indicating that direct anterior decompressions were thorough and effective. The follow-up period was 60–108 months, and the average was 79.6 months. The 5-year average symptom improvement rate, effectiveness rate, and fineness rate were 78.36 %, 100 % (89/89), and 86.52 % (77/89), respectively.

Conclusions

For CSM with compression coming from the front side, proper anterior decompression based on the specific conditions could directly eliminate the compression. Through long-term follow-up, the effect of decompression became observable.