The standard of care for progressive spinal deformity that is greater than 45-50 degrees in growing children is deformity correction with spinal fusion and instrumentation. This sacrifice both spinal ...motion and further spinal growth of the fused region. Idiopathic scoliosis in particular is associated with disproportionate anterior spinal column length compared to the posterior column (hypokyphosis) that is associated with the coronal (scoliosis) and axial plane (rib and lumbar prominence) deformities. In theory, application of compression to the convex and anterior aspects of vertebrae could decrease both anterior and lateral growth via the Hueter-Volkmann principle, while allowing growth on the concave and posterior aspect resulting in spinal realignment created by altered growth. Animal models and preliminary clinical experience suggest spinal growth can be modulated in this way using a flexible tether applied to the convex side of scoliotic vertebral column. Experimental studies suggest disc health is preserved with a flexible tether as disc motion is maintained during the growth period. Anterolateral tethering been performed via a thoracoscopic spinal approach clinically for a number of years and the early clinical outcomes are beginning to appear in the literature. Initial results of anterolateral tethering in growing patients with spinal deformities are encouraging, however the results 3-4 years after the procedure are somewhat mixed. Further research is ongoing and many remain optimistic that improvements in technology and understanding will continue to lead to better patient outcomes.
BACKGROUND:Anterior vertebral body tethering (AVBT) has been introduced as a means of correcting scoliosis without fusion. The purpose of this study was to compare outcomes for patients with thoracic ...idiopathic scoliosis between a group of patients who underwent AVBT and a matched cohort of patients treated with posterior spinal fusion and instrumentation (PSF).
METHODS:A retrospective study of patients who underwent AVBT and PSF for idiopathic scoliosis was conducted. The inclusion criteria were determined on the basis of the AVBT cohortprimary thoracic idiopathic scoliosis with a curve magnitude between 40° and 67°, Risser stage of ≤1, age of 9 to 15 years, no prior spine surgery, index surgery between 2011 and 2016, and minimum follow-up of 2 years. Demographic, radiographic, clinical, and patient-reported outcomes and revisions were compared between groups.
RESULTS:There were 23 patients in the AVBT cohort and 26 patients in the PSF cohort. The mean follow-up (and standard deviation) was similar between groups3.4 ± 1.1 years for the AVBT group and 3.6 ± 1.6 years for the PSF group (p = 0.6). Preoperatively, the groups were similar in all measurements of radiographic and clinical deformity, with mean main thoracic curves of 53° ± 8° for the AVBT group and 54° ± 7° for the PSF group (p = 0.4). At the time of final follow-up, the AVBT cohort had significantly more residual deformity, with a mean thoracic curve of 33° ± 18° compared with 16° ± 6° for the PSF group (p < 0.001). There were 9 revision procedures in the AVBT cohort (with 3 conversions to PSF and 3 more pending) and none in the PSF cohort. Revisions occurred at a mean postoperative time of 2.3 years (range, 1.2 to 3.7 years). Twelve patients (52%) had evidence of broken tethers; of these patients, 4 underwent revision. The post-intervention patient-reported outcomes were similar.
CONCLUSIONS:Both AVBT and PSF resulted in postoperative correction; however, 2-year correction was better maintained in the PSF group. There were no differences in post-intervention patient-reported outcomes. AVBT resulted in less deformity correction and more revision procedures than PSF, but resulted in the delay or prevention of PSF in the majority of patients.
LEVEL OF EVIDENCE:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Anterior vertebral body tethering (AVBT) has been introduced as a means of correcting scoliosis without fusion. The purpose of this study was to compare outcomes for patients with thoracic idiopathic ...scoliosis between a group of patients who underwent AVBT and a matched cohort of patients treated with posterior spinal fusion and instrumentation (PSF).
A retrospective study of patients who underwent AVBT and PSF for idiopathic scoliosis was conducted. The inclusion criteria were determined on the basis of the AVBT cohort: primary thoracic idiopathic scoliosis with a curve magnitude between 40° and 67°, Risser stage of ≤1, age of 9 to 15 years, no prior spine surgery, index surgery between 2011 and 2016, and minimum follow-up of 2 years. Demographic, radiographic, clinical, and patient-reported outcomes and revisions were compared between groups.
There were 23 patients in the AVBT cohort and 26 patients in the PSF cohort. The mean follow-up (and standard deviation) was similar between groups: 3.4 ± 1.1 years for the AVBT group and 3.6 ± 1.6 years for the PSF group (p = 0.6). Preoperatively, the groups were similar in all measurements of radiographic and clinical deformity, with mean main thoracic curves of 53° ± 8° for the AVBT group and 54° ± 7° for the PSF group (p = 0.4). At the time of final follow-up, the AVBT cohort had significantly more residual deformity, with a mean thoracic curve of 33° ± 18° compared with 16° ± 6° for the PSF group (p < 0.001). There were 9 revision procedures in the AVBT cohort (with 3 conversions to PSF and 3 more pending) and none in the PSF cohort. Revisions occurred at a mean postoperative time of 2.3 years (range, 1.2 to 3.7 years). Twelve patients (52%) had evidence of broken tethers; of these patients, 4 underwent revision. The post-intervention patient-reported outcomes were similar.
Both AVBT and PSF resulted in postoperative correction; however, 2-year correction was better maintained in the PSF group. There were no differences in post-intervention patient-reported outcomes. AVBT resulted in less deformity correction and more revision procedures than PSF, but resulted in the delay or prevention of PSF in the majority of patients.
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Background Obtaining accurate measurements of scoliosis from two-dimensional (2-D) radiographs can be challenging because of the three-dimensional (3-D) nature of the deformity. Previous studies have ...shown that the sagittal plane, in particular, is misrepresented on 2-D radiographs because of the influence of axial plane rotation. The purpose of the current study was to define a methodology for measuring the 3-D segmental sagittal alignment of the spine in patients with adolescent idiopathic scoliosis (AIS) and to assess the effect of axial plane rotation on differences between 3-D and 2-D measures of deformity. Methods Preoperative and postoperative EOS images of 120 consecutive patients with AIS (primary thoracic curves) treated with segmental thoracic pedicle-screw instrumentation were analyzed in the “3-D sagittal plane.” The technique measured 3-D kyphosis or lordosis in the specific plane of sagittal motion for each spinal motion segment. The kyphosis (+) and lordosis (−) values of the segments from T 0025 to T 0060 were summed to give the 3-D measurement of T5-T12 kyphosis. These values were compared with the standard 2-D measurements of T5-T12 kyphosis on lateral radiographs, and a correlation analysis with regard to axial plane rotation of the apex was performed. Results The average age (and standard deviation) of the patients was 14 ± 2 years. The mean preoperative Cobb angle on the standard 2-D view was 55° ± 10° and on the 3-D view was 52° ± 9° (p ≤ 0.001). On the 3-D view, the mean preoperative T5-T12 kyphosis was 6° ± 14°, and the kyphosis significantly increased to 26° ± 6° postoperatively (p < 0.001). The T5-T12 kyphosis on the standard 2-D view measured 18° ± 13° preoperatively and 27° ± 6° postoperatively (p < 0.001). The difference between the 2-D and 3-D measurements of T5-T12 kyphosis strongly correlated with apical vertebral rotation (r = 0.85; p < 0.01). Conclusions Routine 2-D measurements of thoracic kyphosis erroneously underestimate the preoperative loss of kyphosis in AIS because of errors associated with axial plane rotation, an inherent component of thoracic scoliosis. Level of Evidence Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.
BACKGROUND:Anterior spinal growth tethering (ASGT) has been shown to alter spinal growth with the potential to correct scoliosis while maintaining spine flexibility. The purpose of this study was to ...report the 2 to 4-year outcomes of ASGT in skeletally immature patients with thoracic scoliosis.
METHODS:We conducted a retrospective review of patients with thoracic scoliosis who underwent ASGT with a minimum of 2 years of follow-up. Patient demographics, perioperative data, and radiographic outcomes are reported. A “successful” clinical outcome was defined as a residual curve of <35° and no posterior spinal fusion indicated or performed at latest follow-up.
RESULTS:Seventeen patients met the inclusion criteria. The etiology was idiopathic for 14 and syndromic for 3. The mean follow-up was 2.5 years (range, 2 to 4 years). Preoperatively, all patients were at Risser stage 0, with a mean age at surgery of 11 ± 2 years (range, 9 to 14 years). There was an average of 6.8 ± 0.5 vertebrae tethered per patient. The average thoracic curve magnitude was 52° ± 10° (range, 40° to 67°) preoperatively, 31° ± 10° immediately postoperatively, 24° ± 17° at 18 months postoperatively, and 27° ± 20° at latest follow-up (51% correction; range, 5% to 118%). Revision surgery was performed in 7 patients4 tether removals due to complete correction or overcorrection, 1 lumbar tether added, 1 tether replaced due to breakage, and 1 revised to a posterior spinal fusion. In 3 additional patients, posterior spinal fusion was indicated due to progression. Eight (47%) of the patients had a suspected broken tether. Ten (59%) of the 17 were considered clinically successful.
CONCLUSIONS:Despite most patients having some remaining skeletal growth at the time of review, the results of the current study demonstrate that at mid-term follow-up, ASGT showed a powerful, but variable, ability to modulate spinal growth and did so with little perioperative and early postoperative risk. Fusion was avoided for 13 of the 17 patients. The overall success rate was 59%, with a 41% revision rate. Understanding the parameters leading to success or failure will be critical in advancing a reliable definitive nonfusion treatment for progressive scoliosis in the future.
LEVEL OF EVIDENCE:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
STUDY DESIGN.A prospective multicenter study.
OBJECTIVE.To evaluate the effects of sparing lumbar motion segments on spinal mobility and Scoliosis Research Society-22 scores at 10 years after spinal ...fusion for major thoracic adolescent idiopathic scoliosis (AIS).
SUMMARY OF BACKGROUND DATA.In surgical correction for major thoracic AIS, the long-term benefits of sparing lumbar motion segments remain unclear.
METHODS.A prospective multicenter registry was reviewed and patients with major thoracic AIS (Lenke types 1–4) and availability of both preoperative and 10-year postoperative mobility data were included. Spinal fusions ending at L1 or above were defined as thoracic fusions (T), and at L2 or below as thoracic and lumber fusions (T + L). Spinal mobility was evaluated with a measuring tape. The excursions between the starting and ending positions were measured using the distance from the spinous processes of C7 to S1 for forward flexion (FF), and the distance from the tip of the middle finger to the floor for lateral flexion (LF). Substantial reduction of mobility was defined as a reduction rate (a ratio of postoperative change divided by preoperative mobility) of 40% or more. Motion data were correlated with lowest instrumented vertebra levels and group comparisons were performed.
RESULTS.We identified 151 patients (average age, 25.1 years). The spinal mobility decreased with more distal lowest instrumented vertebrae (FF, rho = 0.208; right LF, 0.257; left LF, 0.371; P ≤ 0.01). Consequently, the incidence of substantial reduction of mobility was lower in the T group (n = 109) than in the T + L group (n = 42) (FF17.4% vs. 50%, LF14.8% vs. 51.2%; P < 0.001). Patients with substantial reduction in LF had lower Scoliosis Research Society-22 scores for pain, function, satisfaction, and total scores than those without substantial reduction at 10-year follow-up (P < 0.05).
CONCLUSION.The sparing of lumbar motion segments demonstrated clinically significant benefits at 10-year postoperatively.Level of Evidence2
Experimental study for systematic evaluation of 3-dimensional (3D) reconstructions from low-dose digital stereoradiography.
To assess the accuracy of EOS (EOS Imaging, Paris, France) 3-dimensional ...(3D) reconstructions compared with 3D computed tomography (CT) and the effect spine positioning within the EOS unit has on reconstruction accuracy.
Scoliosis is a 3D deformity, but 3D morphological analyses are still rare. A new low-dose radiation digital stereoradiography system (EOS) was previously evaluated for intra/interobserver variability, but data are limited for 3D reconstruction accuracy.
Three synthetic scoliotic phantoms (T1-pelvis) were scanned in upright position at 0°, ±5°, and ±10° of axial rotation within EOS and in supine position using CT. Three-dimensional EOS reconstructions were superimposed on corresponding 3D computed tomographic reconstructions. Shape, position, and orientation accuracy were assessed for each vertebra and the entire spine. Additional routine planer clinical deformity measurements were compared: Cobb angle, kyphosis, lordosis, and pelvic incidence.
Mean EOS vertebral body shape accuracy was 1.1 ± 0.2 mm (maximum 4.7 mm), with 95% confidence interval of 1.7 mm. Different anatomical vertebral regions were modeled well with root-mean-square (RMS) values from 1.2 to 1.6 mm. Position and orientation accuracy of each vertebra were high: RMS offset was 1.2 mm (maximum 3.7 mm) and RMS axial rotation was 1.9° (maximum 5.8°). There was no significant difference in each of the analyzed parameters (P > 0.05) associated with varying the rotational position of the phantoms in EOS machine. Planer measurements accuracy was less than 1° mean difference for pelvic incidence, Cobb angle (mean 1.6°/maximum 3.9°), and sagittal kyphosis (mean less than 1°, maximum 4.9°).
The EOS image acquisition and reconstruction software provides accurate 3D spinal representations of scoliotic spinal deformities. The results of this study provide spinal deformity surgeons evidence pertaining to this new upright 3D imaging technology that may aid in the clinical diagnosis and decision making for patients with scoliosis.
Retrospective multicenter review.
Determine the definition, indications, results, and outcomes, focusing on complications of vertebral column resection (VCR) for severe pediatric spinal deformity.
...The strict definition of the VCR procedure, indications, results, outcomes, and the numerous, potentially serious complications are unknown or controversial, and a large multicenter review has never been performed.
A total of 147 patients treated by 7 pediatric spinal deformity surgeons were reviewed-seventy-four females and 73 males, with an average age of 13.7 years, an average of 1.6 (range, 1-5) vertebrae resected, and an average follow-up of 17 months (range, 0.5-64 mo). The strict definition of VCR used was a "3-column circumferential vertebral osteotomy creating a segmental defect with sufficient instability to require provisional instrumentation."
Indications for a VCR were divided into 5 diagnostic categories: kyphoscoliosis (n = 52), severe scoliosis (n = 37), congenital deformity (n = 28), global kyphosis (n = 17), and angular kyphosis (n = 13). Eighty-four primary and 63 revision patients with 174 operative procedures, 127 posterior-only (17 staged), and 20 patients combined anterior-posterior (10 staged) were reviewed. Average preoperative upright, flexibility, and postoperative Cobb measures (% correction or average kyphosis decrease) were kyphoscoliosis: 91°, 65°, 44° (51% coronal), 104°, 81°, and 47° (decrease, 57° sagittal); severe scoliosis: 104°, 78°, and 33° (67%); congenital deformity: 47°, 38°, 22° (46% coronal), 56°, 48°, and 32° (decrease, 24° sagittal); global kyphosis: 101°, 79°, and 47° (decrease, 54°); and angular kyphosis: 88°, 90°, and 38° (decrease, 50°), respectively. Operative time averaged 545 minutes (range, 204-1355 min) and estimated blood loss averaged 1610 mL (range, 50-8244 mL) for an average 65% blood volume loss (range, 6%-316%). Eighty-six patients (59%) developed a complication, 39 patients (27%) having an intraoperative neurological event (spinal cord monitoring change or failed wake-up test); however, no patient had complete permanent paraplegia.
A total of 147 consecutive pediatric VCRs performed by 7 surgeons demonstrated excellent radiographical correction. However, these complex reconstructions were associated with a 59% complication rate, thus emphasizing the challenging nature of these patients and procedures.
Retrospective review.
To compare the incidence of and risk factors for proximal junctional kyphosis (PJK) in adolescent idiopathic scoliosis (AIS) following posterior spinal fusion using hook, ...pedicle screw, or hybrid constructs.
Proximal junctional kyphosis is a recently recognized phenomenon in adults and adolescents after AIS surgery. The postoperative effect on PJK with the use of hooks, hybrid constructs, or screws has not been compared in a multicenter study to date.
From a multicenter database, the preoperative and 2-year follow-up radiographic measurements from 283 patients with AIS treated with posterior spinal fusion using hooks (group 1, n = 51), hybrid constructs (group 2, n = 177), pedicle screws (group 3, n = 37), and pedicle screws with hooks only at the top level (group 4, n = 18) were compared.
The average proximal level kyphosis at 2 years after surgery was 8.2 degrees (range -1 to 18) in the all screw constructs, representing a significant increase when compared with hybrid and all hook constructs, 5.7 degrees (P = 0.02) and 5.0 degrees (P = 0.014), respectively. Conversely, average postoperative T5-T12 kyphosis was significantly less (P = 0.016) in the screw group compared with the all hook group. Of potential interest, but currently not statistically significant, was the trend towards a decrease in proximal kyphosis in constructs with all pedicle screws except hooks at the most cephalad segment, 6.4 degrees . The incidence of PJK (assuming PJK is a kyphotic deformity greater than 15 degrees ) was 0% in group 1, 2.3% in group 2, 8.1% in group 3, and 5.6% in group 4 (P = 0.18). Patients with PJK had an increased body mass index compared with those who did not meet criteria for PJK (P = 0.013).
Adjacent level proximal kyphosis was significantly increased with pedicle screws, but the clinical significance of this is unclear. A potential solution is the substitution of hooks at the upper-instrumented vertebrae, but further investigation is required.
BACKGROUND:Reporting accurate surgical complication rates to patients and their families is important in the management of adolescent idiopathic scoliosis (AIS). In this study, we report the rate of ...major complications following the surgical treatment of AIS both in the perioperative period and among patients with a minimum of 2 years of follow-up.
METHODS:We reviewed the prospectively collected data of a multicenter registry of patients who underwent surgical treatment of AIS during the period of 1995 to 2014 in order to identify all complications. A complication was defined as “major” if it resulted in reoperation or in spinal cord or nerve root injury, or was life-threatening. A total of 3,582 patients with preoperative and early postoperative data (4 to 6 weeks of follow-up) were included. A subset of 2,220 patients with a minimum of 2 years of follow-up comprised the cohort for delayed complications. Overall complication rates were calculated, as was the percentage of complications according to the year of the index surgery and type of surgical approach.
RESULTS:The mean age of the 3,582 patients at the time of surgery was 14.8 ± 2.2 years. The average major curve magnitude was 56° ± 13° for thoracic curves and 51° ± 11° for lumbar. In 365 patients, anterior spinal fusion (ASF) with instrumentation was performed, and in 3,217 patients, posterior spinal fusion (PSF) with instrumentation was performed; 142 patients in the PSF group underwent concomitant anterior release. There were 192 major complications, with 93 (2.6%) occurring perioperatively. Perioperative complications included wound-related (1.0% of the patients), neurologic (0.5%), pulmonary (0.4%), instrumentation-related (0.4%), and gastrointestinal (0.2%) complications. One patient died. The mean annual perioperative major complication rate based on the year of surgery ranged from 0% to 10.5%. The complication rate by surgical approach was 3.0% for ASF and 2.6% for PSF (2.4% for PSF only and 5.6% for PSF with anterior release). The major complication rate for the 2,220 patients with at least 2 years of follow-up was 4.1%; all but 1 had a reoperation (4.1%). The majority of these major complications were wound and instrumentation-related (1.9% and 0.8%, respectively).
CONCLUSIONS:After surgery for AIS, a 2.6% rate of perioperative major complications and a 4.1% rate of major complications at 2 or more years after surgery can be anticipated. The complication rate decreased over the period of study.
LEVEL OF EVIDENCE:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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