Linda A. Koester

Posterior Vertebral Column Resection for Severe Pediatric Deformity : Minimum Two-Year Follow-up of Thirty-Five Consecutive Patients

Study Design. Retrospective review of a prospectively accrued patient cohort. Objective. The ability to treat severe pediatric spinal deformity through an all-posterior vertebral column resection (VCR) has obviated the need for a circumferential approach in both primary and revision settings. We examined indications, correction rates, and complications of this challenging procedure in the pediatric population. Summary of Background Data. Traditionally, severe pediatric spinal deformities were treated through a combined anterior/posterior spinal fusion. Methods. Between 2000 and 2005, 35 consecutive patients underwent a posterior-only VCR by 1 of 2 surgeons at a single institution. Patients were divided into 5 diagnostic categories: (1) severe scoliosis (S) (n = 2; mean, 115°; range, 79–150°; average flexibility, 12%); (2) global kyphosis (GK) (n = 3; mean, 101°; range, 91–113°; average flexibility, 16%); (3) angular kyphosis (AK) (n = 10; mean, 86°; range, 45–135°, average flexibility, 23%); (4) kyphoscoliosis (KS) (n = 8; mean kyphosis, 103°/scoliosis 87°; mean combined, 190°; range, 144–237°); (5) congenital scoliosis (CS) (n = 12; mean, 43°; range, 23–69°; average flexibility, 20%). There were 20 primary/15 revision surgeries. There were 20 one-level, 11 two-level, and 4 three-level resections. Results. The major curve correction averaged: Group S = 61°/51%, Group GK = 56°/55%, Group AK = 51°/58%, Group KS = 98°/54%, and Group CS = 24°/60%. The average OR time was 460 minutes (range, 210–822), with an average EBL of 691 mL (range, 125–2200). There were no spinal cord-related complications; however, 2 patients (8.5%) lost intraoperative neuromonitoring data during correction with data returning to baseline following prompt surgical intervention. Two patients had implant revisions, 1 for a delayed deep infection at 2 years and the other for implant prominence at 3-year follow-up. Conclusion. A posterior-based VCR is a safe but challenging technique to treat severe primary or revision pediatric spinal deformities. Intraoperative SCM (especially motor-evoked potentials) is mandatory to prevent spinal cord-related neurologic complications. Dramatic radiographic and clinical correction of these deformities can be obtained via a posterior-only approach.

Proximal Junctional Vertebral Fracture in Adults After Spinal Deformity Surgery Using Pedicle Screw Constructs: Analysis of Morphological Features

Study Design. A retrospective comparative study. Objective. To investigate the morphologic features of proximal vertebral fractures in adults following spinal deformity surgery using segmental pedicle screw instrumentation. Summary of Background Data. Fractures above pedicle screw constructs are a clinical problem that warrants further investigation for prevention and treatment. Methods. Ten adult patients (6 lumbar scoliosis, 4 degenerative sagittal imbalance) who underwent segmental spinal instrumented fusion were analyzed. Patients were divided into 2 groups according to the features of vertebral fracture: upper instrumented vertebral collapse + adjacent vertebral subluxation (SUB group: n = 5), and adjacent vertebral fracture (Fracture group: n = 5). Results. Both groups demonstrated a high frequency of osteopenia and all patients in the SUB group had comorbidities before surgery. The SUB group demonstrated a shorter interval between initial surgery and the fracture (subluxation: 3 ± 1.9 months; fracture: 33 ± 25.3 months, P < 0.05), and hypokyphosis (T5–T12) in the thoracic region before surgery (SUB: 13° ± 6.4°; fracture: 33° ± 15.6°). Both groups demonstrated severe global sagittal imbalance (SUB: 151 ± 62.8 mm; fracture: 94 ± 102.2 mm), and hypolordosis (T12–S1) in the lumbar spine (SUB: −19° ± 24.4°; fracture: −33° ± 22.7°) before surgery. Global sagittal imbalance in the SUB group was corrected to 8 ± 17.4 mm immediately postoperative (P < 0.05), but increased to 64 ± 19.9 mm after the junctional fractures (P < 0.05). The SUB group demonstrated a significantly higher wedging rate (SUB: 65% ± 12.4%; fracture: 36% ± 16.0%, P < 0.05) and greater local kyphosis (SUB: 42° ± 11.1°; fracture: 17° ± 4.1°, P < 0.05) after the fracture. Two of 5 patients in the SUB group demonstrated severe neurologic deficit from E to B after the fractures by a modified Frankel classification. Conclusion. Old age, osteopenia, preoperative comorbidities, and severe global sagittal imbalance were found to be frequent in patients with proximal junctional fracture. In addition, marked correction of sagittal malalignment might be considered as a risk factor of upper instrumented vertebra collapse followed by adjacent vertebral subluxation, which occurred in the first 6 months after corrective surgery with the potential for causing severe neurologic deficit because of the severe local kyphotic deformity.

Comparison of surgical treatment in Lenke 5C adolescent idiopathic scoliosis: anterior dual rod versus posterior pedicle fixation surgery: a comparison of two practices.

Study Design. Multicenter analysis of 2 groups of patients surgically treated for Lenke 5C adolescent idiopathic scoliosis (AIS). Objective. Compare patients with Lenke 5C scoliosis surgically treated with anterior spinal fusion with dual rod instrumentation and anterior column support with patients surgically treated with posterior release and pedicle screw instrumentation. Summary of Background Data. Treatment of single, structural, lumbar, and thoracolumbar curves in patients with AIS has been the subject of some debate. Advocates of the anterior approach assert that their technique spares posterior musculature and may save distal fusion levels, and that with dual rods and anterior column support the issues with nonunion and kyphosis have been obviated. Advocates of the posterior approach assert that with the change to posterior pedicle screw based instrumentation that correction and levels are equivalent, and the posterior approach avoids the issues with nonunion and kyphosis. This report directly compares the results of posterior versus anterior instrumented fusions in the operative treatment of adolescent idiopathic Lenke 5C curves. Methods. We analyzed 62 patients with Lenke 5C based on radiographic and clinical data at 2 institutions: 31 patients treated with posterior, pedicle-screw instrumented fusions at 1 institution (group PSF); and 31 patients with anterior, dual-rod instrumented fusions at another institution (group ASF). Multiple clinical and radiographic parameters were evaluated and compared. Results. The mean age, preoperative major curve magnitude, and preoperative lowest instrumented vertebral (LIV) tilt were similar in both groups (age: PSF = 15.5 years, ASF = 15.6 years; curve size: PSF = 50.3° ± 7.0°, ASF = 49.0° ± 6.6°; LIV tilt: PSF = 27.5° ± 6.5°, ASF = 27.8° ± 6.2°). After surgery, the major curve corrected to an average of 6.3° ± 3.2° (87.6% ± 5.8%) in the PSF group, compared with 12.1° ± 7.4° (75.7% ± 14.8%) in the ASF group (P < 0.01). At final follow-up, the major curve measured 8.0° ± 3.0° (84.2% ± 5.8% correction) in the PSF group, compared with 15.9° ± 9.0° (66.6% ± 17.9%) in the ASF group (P = 0.01). This represented a loss of correction of 1.7° ± 1.9° (3.4% ± 3.7%) in the PSF group, and 3.8° ± 4.2° (9.4% ± 10.7%) in the ASF group (P = 0.028). The LIV tilt decreased to 4.1° ± 3.4° after surgery in the PSF group, and 4.5° ± 3.7° in the ASF group. At final follow-up, the LIV tilt was 5.1° ± 3.5° in the PSF group, and 4.5° ± 3.7° in the ASF group. EBL was identical in both groups, and length of hospital stay was significantly (P < 0.01) shorter in the PSF group (4.8 vs. 6.1 days). There were no complications in either group which extended hospital stay or required an unplanned second surgery. Conclusion. At a minimum of 2-year follow-up, adolescents with Lenke 5C curves demonstrated statistically significantly better curve correction, less loss of correction over time, and shorter hospital stays when treated with a posterior release with pedicle screw instrumented fusion compared with an anterior instrumented fusion with dual rods for similar patient populations.

Can Posterior-Only Surgery Provide Similar Radiographic and Clinical Results as Combined Anterior (Thoracotomy/Thoracoabdominal)/Posterior Approaches for Adult Scoliosis?

Study Design. Retrospective matched cohort analysis. Objective. To determine if posterior-only (post-only) surgical techniques consisting of pedicle screws, osteotomies, transforaminal lumbar interbody fusion, and bone morphogenetic protein-2 may provide similar results as compared anterior (thoracotomy/thoracoabdominal)/posterior surgical approaches for the treatment of adult spinal deformity with respect to correction, fusion rates, or outcomes. Summary of Background Data. Combined anterior/posterior (A/P) fusion has traditionally been used to treat many adult scoliosis deformities. Anterior approaches negatively impact pulmonary function and require additional operative time and anesthesia. Methods. Twenty-four patients who had A/P fusion for primary adult scoliosis (16 staged, 8 same-day) were matched with a cohort of 24 patients who had post-only treatment. Anterior fusion was performed via a thoracotomy (n = 1)/thoracoabdominal (n = 23) approach. All post-only surgeries were under one anesthesia. Minimum 2-year follow-up included radiographic, clinical, and outcomes data. Results. There were no significant differences between groups for age, gender, diagnosis, comorbidities, preoperative curve magnitudes, or global balance. Postoperative radiographic correction and alignment were similar for both groups except for thoracolumbar curve percent improvement which was statistically better in the post-only group (P = 0.03). The average surgical time was higher in A/P versus post-only group (11.6 vs. 6.9 hours, P < 0.0001) as was total estimated blood loss (1330 vs. 980 mL, P = 0.04). Hospital length of stay (LOS) was longer in A/P versus post-only group (11.9 vs. 8.3 days, P = 0.03). There were no significant differences between postoperative complications. Revision surgery was performed in 5 A/P and 2 post-only patients. Higher pseudarthrosis rates found in the A/P versus post-only (17 vs. 0%) were not significant (P = 0.11). SRS-30 and Oswestry scores reflected a similar patient assessment before surgery, and improvement between groups at follow-up. Conclusion. Post-only adult scoliosis surgery achieved similar correction to A/P surgery while decreasing blood loss, operative time, length of stay, and avoiding additional anesthesia. Complications, radiographic, and clinical outcomes were similar at over 2-year follow-up.

Comparison of standard 2-rod constructs to multiple-rod constructs for fixation across 3-column spinal osteotomies.

Study Design. Retrospective matched-cohort comparative study. Objective. Compare radiographical outcomes after the use of a standard 2-rod construct (2-RC) versus a multiple-rod construct (multi-RC) across 3-column osteotomy sites in a matched cohort with severe kyphosis and/or scoliosis with minimum 2-year follow-up. Summary of Background Data. Three-column osteotomies are used for treating severe spinal deformities, typically with a standard 2-RC across the highly unstable osteotomy site. Methods. Between 1996 and 2010, patients undergoing a 3-column osteotomy by a single surgeon were matched for age/diagnosis/vertebra(e) resected/levels fused and curve magnitude. Sixty-six control patients with a 2-RC were identified and appropriately matched to 66 consecutive patients with a multi-RC across the 3-column osteotomy site. Each group included 50 patients with lumbar pedicle subtraction osteotomy and 16 patients with vertebral column resection. Radiographs were measured using standard adult deformity criteria. Results. Averages were compared for 2-RC versus multi-RC demonstrating no statistical differences in mean age at surgery, vertebrae resected, levels fused, bone morphogenetic protein used (patients), or average preoperative Cobb magnitude. There were significant differences in the occurrence of rod breakage and revision surgery for pseudarthroses at the 3-column osteotomy site (rod breakage: 2-RC: 11 vs. multi-RC: 2, P = 0.002; and revision: 2-RC: 6 vs. multi-RC: 0, P = 0.011). There was no complete implant failure in the multi-RC group but 2 patients had partial implant failure without symptomatic pseudarthrosis. Eight patients in each group (12%) developed a pseudarthrosis above or below the osteotomy site. Conclusion. The use of a multi-RC is a safe, simple, and effective method to provide increased stability across 3-column osteotomy sites to significantly prevent implant failure and symptomatic pseudarthrosis versus a standard 2-RC. We strongly recommend using a multi-RC to stabilize 3-column osteotomies of the thoracic and lumbar spine. Level of Evidence: 3

RhBMP-2 is superior to iliac crest bone graft for long fusions to the sacrum in adult spinal deformity: 4- to 14-year follow-up.

Study Design. Matched cohort comparison. Objective. To compare the use of bone morphogenetic protein (BMP) or iliac crest bone graft (ICBG) on the long-term outcomes in patients undergoing long fusions to the sacrum for adult spinal deformity. Summary of Background Data. No long-term studies beyond a 2-year follow-up have been performed comparing the use of BMP versus ICBG for fusion rates in long fusions to the sacrum in adult spinal deformity. Methods. A total of 63 consecutive patients, from 1997–2006, comprised of 31 patients in the BMP group and 32 patients in the ICBG group, operated on at a single institution with a minimum 4-year follow-up (4–14 yr) were analyzed. Inclusion criteria were ambulators who were candidates for long fusions (thoracic as the upper level) to the sacrum. Exclusion criteria were revisions, neuromuscular scoliosis, ankylosing spondylitis, and patients who had both BMP and ICBG used for fusion. Oswestry Disability Index and 3 domains of the Scoliosis Research Society score were used to assess outcomes. Results. The 2 groups were similar with respect to age, sex, smoking history, comorbidities, BMI, number of fusion levels and Cobb angles. Eight patients in the BMP group underwent a posterior only, whereas 23 underwent combined anterior and posterior (A/P) surgery. All 32 patients in the ICBG had A/P fusion. The average BMP level was 11.1 mg (3–36 mg). The rate pseudarthrosis was 6.4% (2/31) in the BMP and 28.1% (9/32) in the ICBG group (P = 0.04) using Fisher exact test and odds ratio = 5.67. The fusion rates for BMP group were 93.5% and 71.9% for the ICBG group. Oswestry Disability Indexes were similar between groups. However, the BMP group demonstrated superior sum composite Scoliosis Research Society scores in pain, self-image and function domains (P = 0.02). Conclusion. BMP is superior to ICBG in achieving fusion in long constructs in adult deformity surgery. The rate of pseudarthrosis was significantly higher in the ICBG group than BMP group. The concentration and dosage of recombinant human bone morphogenetic protein 2 (rhBMP-2) used seems to have an effect on the rate of fusion and pseudarthrosis rate because no patient receiving more than 5 mg per level had apparent or detected pseudarthroses (n = 20/20). Level of Evidence: 3

Etiology and revision surgical strategies in failed lumbosacral fixation of adult spinal deformity constructs.

Study Design. Retrospective case analysis. Objective. The purpose of this study was to evaluate the etiology and salvage strategies of failed lumbosacral fixation in adult spinal deformity patients. Summary of Background Data. When extending a long spinal deformity fusion to the sacrum, the lumbosacral junction is a common site for implant problems and pseudarthrosis. Methods. Clinical and radiographic results of 33 patients (26 women/seven men; average age, 53.5 years; range, 21–73) diagnosed and treated for lumbosacral fixation failure between 1995 and 2007 were reviewed. Twenty-one of the 33 patients underwent revision surgery at one institution for these failures and were followed postoperatively for more than 2 years (average, 50.7 months). Results. Twenty-nine of these 33 patients had two sacral screws, two patients one sacral screw, and two patients none. Bicortical sacral screws were placed in 18 patients, only 12 had distal fixation to the sacral screws (bilateral iliac screws, n = 9; others, n = 3). Seventeen of 19 patients without distal fixation to the sacral screws had screw loosening/pullout at L5 or S1. Anteriorly at L5–S1: 4/6 bone grafts collapsed, 5 of 15 intervertebral discs without anterior column support collapsed, and two of 12 titanium cages subsided into the endplates. Rod breakage between L5 and S1 (n = 9) was seen only in patients with distal fixation to the sacral screws. Nineteen of 21 revision patients received two bicortical sacral screws, whereas 20 received distal fixation to the sacral screws consisting of bilateral iliac screws in 16. Nineteen patients received anterior column support at L5–S1. Fifteen of 21 revision patients achieved solid fusion at ultimate follow-up; however, six had additional rod breakage or dislodgement at the lumbosacral junction. Conclusion. With long fusions to the sacrum in the treatment of spinal deformity, the use of bilateral S1 screws alone may allow for screw loosening/pullout and/or L5–S1 cage/graft collapse/subsidence. Adding bilateral iliac screws and an anterior structural cage/graft at L5–S1 will protect the S1 screws, but may still allow L5–S1 rod breakage/dislodgement because of lumbosacral pseudarthrosis. Revision surgery in these patients remains a challenge.

Transforaminal versus anterior lumbar interbody fusion in long deformity constructs: a matched cohort analysis.

Study Design. Prospectively enrolled, retrospectively analyzed matched cohort analysis. Objective. Evaluate the relative merits of transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) when performed in long deformity constructs. Summary of Background Data. Interbody fusion is frequently used at the caudal levels of long-segment spinal deformity instrumentation constructs to protect the sacral implants and enhance fusion rates. However, there is a paucity of literature regarding which technique is more efficacious. Methods. Forty-two patients who underwent TLIF and 42 patients who underwent ALIF were matched with respect to age, sex, comorbidities, curve magnitude, fusion length, and ALIF/TLIF level. Radiographs and clinical outcomes were compared at minimum 2-year follow-up. Results. Age averaged 54.0 years and instrumented vertebrae averaged 13.6. TLIFs had less operative time (481 vs. 595 min, P = 0.0007), but greater blood loss (2011 vs. 1281 mL, P = 0.0002). Overall complications (TLIF, 12/42 vs. ALIF, 15/42) and neurological complications (TLIF, 4/42 vs. ALIF, 3/42) did not differ. One pseudarthrosis occurred at an ALIF level, with none at TLIF levels. Patients who underwent ALIF began with lower SRS scores but showed more improvement (44.4 to 70.7 vs. 58.6 to 70.6, P = 0.0043). ODI scores in both groups improved similarly. Regionally, ALIFs engendered more lordosis than TLIFs at L3–S1 (gain of 6.9° vs. −2.6°, P < 0.0001) but not T12-S1 (gain of 11.5° vs. 7.9°, P = 0.29). Locally, ALIFs created more lordosis at L4–L5 (gain of 5.6° vs. −1.7°, P < 0.0001) and L5–S1 (gain of 2.5° vs. −1.4°, P = 0.022), but not at L3–L4 (gain of 5.3° vs. 4.0°, P = 0.65). Patients who underwent TLIF obtained greater correction of anteroposterior Cobb angles in lumbar (reduction of 22.4° vs. 9.9°, P < 0.0001) and lumbosacral curves (reduction of 10.3° vs. 3.4°, P < 0.0001). Conclusion. Spinal deformity surgery used TLIFs rather than ALIFs resulted in shorter operative time with no difference in complication rates. ALIFs provided more segmental lordosis, whereas TLIFs afforded better correction of scoliotic curves.

Efficacy of perioperative halo-gravity traction for treatment of severe scoliosis (≥100°)

BackgroundThere have been no standardized surgical options for severe scoliotic curvatures ≥100°. Halo-gravity traction is a viable option for surgical treatment of severe scoliosis. The aim of this study was to evaluate the efficacy and safety of perioperative halo-gravity traction for scoliosis curves ≥100° with respect to radiographic outcomes and clinical complications.MethodsA total of 21 scoliosis patients with ≥100° curves (average 118.7°; range 100°-158°) with a minimum 2-year follow-up (average 41.8 months; range 24.0-97.0 months) who underwent spinal instrumented fusion using perioperative halo-gravity traction were analyzed. Diagnoses were neuromuscular scoliosis (n = 10), idiopathic (n = 9), and congenital (n = 2). In all, 15 patients were treated by the anterior release procedure followed by final posterior fusion and 6 patients by posterior fusion alone. Six patients had only preoperative traction preceding posterior fusion alone, 6 patients only staged traction between anterior release and final posterior fusion, and 9 patients had both preoperative traction preceding anterior release and staged traction preceding final posterior fusion. The average overall traction period in all patients was 67 days (range 10–78 days).ResultsRadiographic outcomes demonstrated 51.3% correction of the major Cobb angle, 40 mm correction of apical vertebral translation, 76 mm increase of T1-S1 length, and 20.7% increase of space available for lungs at the ultimate follow-up (all comparisons P < 0.05). Preoperative traction demonstrated 27.5% correction of the major curve Cobb angle, 51.5 mm increase of T1-S1 length, 14.9% increase of space available for the lungs (all comparisons P < 0.05). Staged traction after anterior release demonstrated 37.2% correction of the major curve Cobb angle, 26.1 mm correction of apical vertebral translation, 56.5 mm increase of T1-S1 length, 14.2% increase of space available for the lungs (all comparisons P < 0.05). There were only two patients with a pin-site problem, and one required débridement. There were no neurological deficits or clinical complications.ConclusionsScoliosis patients with ≥100° curves can be managed successfully by corrective fusion surgery concomitant with perioperative halo-gravity traction without significant complications.

Risk factors for and assessment of symptomatic pseudarthrosis after lumbar pedicle subtraction osteotomy in adult spinal deformity.

Study Design. Retrospective review of prospectively collected data. Objective. To assess the prevalence, risk factors, and clinical outcomes for pseudarthrosis after a lumbar pedicle subtraction osteotomy (PSO). Summary of Background Data. There exists no large series that examines pseudarthrosis rates of PSOs. Methods. Data of 171 consecutive patients with adult deformity who underwent a lumbar PSO by 2 surgeons at a single institution with a minimum 2-year follow-up were analyzed. Pseudarthrosis diagnosed through sagittal malalignment and instrumentation failure noted on radiograph was confirmed intraoperatively. Results. Eighteen (10.5%) of 171 patients developed pseudarthrosis after a PSO. Eleven of the 18 patients (6.4% of all patients, 61.1% of the 18 patients with pseudarthrosis) had pseudarthrosis at the PSO site, L3 being the most common; other locations included the lumbosacral junction (4/18), thoracolumbar junction (2/18), and upper thoracic spine (1/18). Preoperative pseudarthrosis level was a predictor of the postoperative level of pseudarthrosis (93%). Fifteen of the 18 patients (83%) had no interbody fusion directly above or below the PSO site, 16 (88%) had a history of pseudarthrosis at the time of PSO surgery and 2 of 3 patients who had prior radiation to the lumbar region developed pseudarthrosis. Most pseudarthroses occurred within the first 2 years (n = 13/18), between 2 and 5 years (n = 3/18), and more than 5 years (n = 2/18) postoperatively. Prior pseudarthrosis (P < 0.0001), pseudarthrosis at the PSO site (P < 0.0001), prior decompression in the lumbar region (P = 0.0037), prior radiation to the lumbar region (P < 0.0001), and presence of inflammatory/neurological disorders (P < 0.0036) were identified as risk factors. All 18 patients with pseudarthroses required revision surgery (posterior-only surgery, n = 12; anteroposterior surgery, n = 6) due to loss of sagittal alignment and pain. The mean pre-revision Scoliosis Research Society score was 85, post-revision score was 95 (P = 0.0166), and the mean pre-revision Oswestry Disability Index score was 42.5, post-revision score was 34.5 (P = 0.0203). Conclusion. The overall prevalence of pseudarthrosis was 10.5% of which 61% occurred at the actual PSO site and Scoliosis Research Society and Oswestry Disability Index scores improved significantly after pseudarthrosis repair. Level of Evidence: 4