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W. Jeffrey Elias, Mark E. Shaffrey and Richard Whitehill

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Melike Mut, M. Beatriz S. Lopes and Mark Shaffrey

Dr. Lucien Rubinstein is best remembered for his significant contributions to the field of neuropathology, particularly in the classification of nervous system tumors. His accomplishments in basic neuro-oncology and in the formulation of diagnostic principles reflected a unique talent for synthesizing fundamental clinicopathological concepts based on skillful diagnostic investigation and a thorough understanding of neurobiology. Dr. Rubinstein was the leader in the establishment of cell cultures from central nervous system (CNS) tumors. He meticulously analyzed both light and electron microscopic features of CNS tumors, recorded his findings, and patiently drew sketches to be shared generously with his colleagues and students. As a pioneer in neuropathology, in his work Dr. Rubinstein set the foundation for many enduring concepts in neurosurgery, neuro-oncology, neurology, and basic tumor biology.

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Rod J. Oskouian, Richard Whitehill, Amir Samii, Mark E. Shaffrey, J. Patrick Johnson and Christopher I. Shaffrey

Both total hip and knee arthroplasty have demonstrated outstanding clinical results. The functional spinal unit composed of the intervertebral disc and facet joints is at least as complex. The intricacies of the coupled motions of the functional spinal unit have made development of an artificial disc a challenge. There have been several failed attempts to create a disc replacement that recapitulates normal motion while providing significant longevity and a low incidence of complications.

Better understanding of the biomechanics of the intervertebral disc complex and improvements in implant material have made successful intervertebral disc replacement a likely reality, now that several artificial discs have completed Food and Drug Administration clinical trials. In this manuscript the authors detail the biomaterials used in disc arthroplasty and discuss joint wear and the host response to wear debris.

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Gregory C. Wiggins, Christopher I. Shaffrey, Mark F. Abel and Arnold H. Menezes

Pediatric spinal deformity results from multiple conditions including congenital anomalies, neuromuscular disorders, skeletal dysplasia, and developmental disorders (idiopathic). Pediatric spinal deformities can be progressive and cause pulmonary compromise, neurological deficits, and cardiovascular compromise. The classification and treatment of these disorders have evolved since surgical treatment was popularized when Harrington distraction instrumentation was introduced.

The advent of anterior-spine instrumentation systems has challenged the concepts of length of fusion needed to arrest curvature progression. Segmental fixation revolutionized the surgical treatment of these deformities. More recently, pedicle screw–augmented segmental fixation has been introduced and promises once again to shift the standard of surgical therapy. Recent advances in thoracoscopic surgery have made this technique applicable to scoliosis surgery.

Not only has surgical treatment progressed but also the classification of different forms of pediatric deformity continues to evolve. Recently, Lenke and associates proposed a new classification for adolescent idiopathic scoliosis. This classification attempts to address some of the shortcomings of the King classification system.

In this article the authors review the literature on pediatric spinal deformities and highlight recent insights into classification, treatment, and surgery-related complications.

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Gregory C. Wiggins, Michael J. Rauzzino, Christopher I. Shaffrey, Russ P. Nockels, Richard Whitehill, Mark E. Shaffrey, James Wagner and Tord D. Alden

This study was conducted to determine the safety, efficacy, and complication rate associated with the anterior approach in the use of a new titanium mesh interbody fusion cage for the treatment of unstable thoracolumbar burst fractures. The experience with this technique is compared with the senior authors' (C.S., R.W., and M.S.) previously published results in the management of patients with unstable thoracolumbar burst fractures.

Between 1996 and 1999, 21 patients with unstable thoracolumbar (T12-L3) burst fractures underwent an anterolateral decompressive procedure in which a titanium cage and Kaneda device were used. Eleven of the 21 patients had sustained a neurological deficit, and all patients improved at least one Frankel grade (average 1.2 grades). There was improvement in outcome in terms of blood loss, correction of kyphosis, and pain, as measured on the Denis Pain and Work Scale, in our current group of patients treated via an anterior approach when compared with the results in those who underwent a posterior approach.

In our current study the anterior approach was demonstrated to be a safe and effective technique for the management of unstable thoracolumbar burst fractures. It offers superior results compared with the posterior approach. The addition of the new titanium mesh interbody cage to our previous anterior technique allows the patient's own bone to be harvested from the corpectomy site and used as a substrate for fusion, thereby obviating the need for iliac crest harvest. The use of the cage in association with the Kaneda device allows for improved correction of kyphosis and restoration of normal sagittal alignment in addition to improved functional outcomes.

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Thomas J. Buell, James H. Nguyen, Marcus D. Mazur, Jeffrey P. Mullin, Juanita Garces, Davis G. Taylor, Chun-Po Yen, Mark E. Shaffrey, Christopher I. Shaffrey and Justin S. Smith

OBJECTIVE

Fixed sagittal spinal malalignment is a common problem in adult spinal deformity (ASD). Various three-column osteotomy techniques, including the extended pedicle subtraction osteotomy (ePSO), may correct global and regional malalignment in this patient population. In contrast to the number of reports on traditional PSO (Schwab grade 3 osteotomy), there is limited literature on the outcomes of ePSO (Schwab grade 4 osteotomy) in ASD surgery. The objective of this retrospective study was to provide focused investigation of radiographic outcomes and complications of single-level lumbar ePSO for ASD patients with fixed sagittal malalignment.

METHODS

Consecutive ASD patients in whom sagittal malalignment had been treated with single-level lumbar ePSO at the authors’ institution between 2010 and 2015 were analyzed, and those with a minimum 2-year follow-up were included in the study. Radiographic analyses included assessments of segmental lordosis through the ePSO site (sagittal Cobb angle measured from the superior endplate of the vertebra above and inferior endplate of the vertebra below the ePSO), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence and LL mismatch, thoracic kyphosis (TK), and sagittal vertical axis (SVA) on standing long-cassette radiographs. Complications were analyzed for the entire group.

RESULTS

Among 71 potentially eligible patients, 55 (77%) had a minimum 2-year follow-up and were included in the study. Overall, the average postoperative increases in ePSO segmental lordosis and overall LL were 41° ± 14° (range 7°–69°, p < 0.001) and 38° ± 11° (range 9°–58°, p < 0.001), respectively. The average SVA improvement was 13 ± 7 cm (range of correction: −33.6 to 3.4 cm, p < 0.001). These measurements were maintained when comparing early postoperative to last follow-up values, respectively (mean follow-up 52 months, range 26–97 months): ePSO segmental lordosis, 34° vs 33°, p = 0.270; LL, 47.3° vs 46.7°, p = 0.339; and SVA, 4 vs 5 cm, p = 0.330. Rod fracture (RF) at the ePSO site occurred in 18.2% (10/55) of patients, and pseudarthrosis (PA) at the ePSO site was confirmed by CT imaging or during rod revision surgery in 14.5% (8/55) of patients. Accessory supplemental rods across the ePSO site, a more recently employed technique, significantly reduced the occurrence of RF or PA on univariate (p = 0.004) and multivariable (OR 0.062, 95% CI 0.007–0.553, p = 0.013) analyses; this effect approached statistical significance on Kaplan-Meier analysis (p = 0.053, log-rank test). Interbody cage placement at the ePSO site resulted in greater ePSO segmental lordosis correction (45° vs 35°, p = 0.007) without significant change in RF or PA (p = 0.304). Transient and persistent motor deficits occurred in 14.5% (8/55) and 1.8% (1/55) of patients, respectively.

CONCLUSIONS

Extended PSO is an effective technique to correct fixed sagittal malalignment for ASD. In comparison to traditional PSO techniques, ePSO may allow greater focal correction with comparable complication rates, especially with interbody cage placement at the ePSO site and the use of accessory supplemental rods.

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Michael J. Rauzzino, Christopher I. Shaffrey, James Wagner, Russ Nockels and Mark Abel

The indications for surgical intervention in patients with idiopathic scoliosis have been well defined. The goals of surgery are to achieve fusion and arrest progressive curvature while restoring normal coronal and sagittal balance. As first introduced by Harrington, posterior fusion, the gold standard of treatment, has a proven record of success. More recently, anterior techniques for performing fusion procedures via either a thoracotomy or a retroperitoneal approach have been popularized in attempts to achieve better correction of curvature, preserve motion segments, and avoid some of the complications of posterior fusion such as the development of the flat-back syndrome. Anterior instrumentation alone, although effective, can be kyphogenic and has been shown to be associated with complications such as pseudarthrosis and instrumentation failure. Performing a combined approach in patients with scoliosis and other deformities has become an increasingly popular procedure to achieve superior correction of deformity and to minimize later complications. Indications for a combined approach (usually consisting of anterior release, arthrodesis with or without use of instrumentation, and posterior segmental fusion) include: prevention of crankshaft phenomenon in juvenile or skeletally immature adolescents; correction of large curves (75°) or excessively rigid curves in skeletally mature or immature patients; correction of curves with large sagittal-plane deformities such as thoracic kyphosis (> 90°) or thoracic lordosis (> 20°); and correction of thoracolumbar curves that need to be fused to the sacrum. Surgery may be performed either in a staged proceedure or, more commonly, in a single sitting. The authors discuss techniques for combined surgery and complication avoidance.

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Edward C. Nemergut and Mark E. Shaffrey

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Mark E. Shaffrey, Elana Farace, David Schiff, James M. Larner, Melike Mut and M. Beatriz S. Lopes

Object. This study was conducted to determine whether proliferative tumor activity, as assessed using the Ki-67 immunohistochemical labeling index (LI), has prognostic utility for patients with Grade II oligoastrocytomas.

Methods. The study period spans the years 1988 to 2000. In a retrospective analysis, the authors selected cases with biopsy-proven diagnoses of Grade II oligoastrocytomas on initial presentation. The authors added new patients to this group and followed all patients prospectively at the University of Virginia Neuro-Oncology Center.

Twenty-three adult patients were followed for at least 1 year (median 40.3 months). Eleven patients with Grade II tumors and initial Ki-67 LIs less than 10% had a significantly longer median time to tumor progression (TTP, 51.8 months compared with 9.9 months) and a longer median survival (93.1 months compared with 16.1 months) than 12 patients with initial Ki-67 LIs of 10% or greater. Twelve patients with Grade III oligoastrocytomas had a mean TTP that was similar to the TTP of patients with Grade II tumors and high Ki-67 LIs (mean 4 months compared with 9.9 months) and duration of survival (13.3 months compared with 16.1 months).

Conclusions. Patients with a Grade II oligoastrocytoma and a Ki-67 LI of 10% or greater have a much shorter TTP and potentially a poorer disease prognosis than expected—more similar to patients with a Grade III oligoastrocytoma. These results indicate that in the future a measure of proliferative activity should be taken into consideration along with the World Health Organization grading criteria for oligoastrocytomas.