Lumbar Level Significantly Influences Postoperative Global Sagittal Balance Following Pedicle Subtraction Osteotomy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: The current evidence regarding how level of lumbar pedicle subtraction osteotomy (PSO) influences correction of sagittal alignment is limited. This study sought to investigate the relationship of lumbar level and segmental angular change (SAC) of PSO with the magnitude of global sagittal alignment correction. METHODS: This study retrospectively evaluated 53 consecutive patients with adult spinal deformity who underwent lumbar PSO at a single institution. Radiographs were evaluated to quantify the effect of PSO on lumbar lordosis (LL), thoracic kyphosis (TK), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), T1-spinopelvic inclination (T1SPI), T1-pelvic alignment (TPA), and sagittal vertical axis (SVA). RESULTS: Significant correlations were found between PSO SAC and the postoperative increase in LL (r = 0.316, P = .021) and PT (r = 0.352, P = .010), and a decrease in TPA (r = -0.324, P = .018). PSO level significantly correlated with change in T1SPI (r = -0.305, P = .026) and SVA (r = -0.406, P = .002), with more caudal PSO corresponding to a greater correction in sagittal balance. On multivariate analysis, more caudal PSO level independently predicted a greater reduction in T1SPI (ß = -3.138, P = .009) and SVA (ß = -29.030, P = .001), while larger PSO SAC (ß = -0.375, P = .045) and a greater number of fusion levels (ß = -1.427, P = .036) predicted a greater reduction in TPA. CONCLUSION: This study identified a gain of approximately 3 degrees and 3 cm of correction for each level of PSO more caudal to L1. Additionally, a larger PSO SAC predicted greater improvement in TPA. While further investigation of these relationships is warranted, these findings may help guide preoperative PSO level selection.

Catastrophic acute failure of pelvic fixation in adult spinal deformity requiring revision surgery: a multicenter review of incidence, failure mechanisms, and risk factors.

OBJECTIVE: There are few prior reports of acute pelvic instrumentation failure in spinal deformity surgery. The objective of this study was to determine if a previously identified mechanism and rate of pelvic fixation failure were present across multiple institutions, and to determine risk factors for these types of failures. METHODS: Thirteen academic medical centers performed a retrospective review of 18 months of consecutive adult spinal fusions extending 3 or more levels, which included new pelvic screws at the time of surgery. Acute pelvic fixation failure was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS: Failure occurred in 37 (5%) of 779 cases and consisted of either slippage of the rods or displacement of the set screws from the screw tulip head (17 cases), screw shaft fracture (9 cases), screw loosening (9 cases), and/or resultant kyphotic fracture of the sacrum (6 cases). Revision strategies involved new pelvic fixation and/or multiple rod constructs. Six patients (16%) who underwent revision with fewer than 4 rods to the pelvis sustained a second acute failure, but no secondary failures occurred when at least 4 rods were used. In the univariate analysis, the magnitude of surgical correction was higher in the failure cohort (higher preoperative T1-pelvic angle [T1PA], presence of a 3-column osteotomy; p < 0.05). Uncorrected postoperative deformity increased failure risk (pelvic incidence-lumbar lordosis mismatch > 10°, higher postoperative T1PA; p < 0.05). Use of pelvic screws less than 8.5 mm in diameter also increased the likelihood of failure (p < 0.05). In the multivariate analysis, a larger preoperative global deformity as measured by T1PA was associated with failure, male patients were more likely to experience failure than female patients, and there was a strong association with implant manufacturer (p < 0.05). Anterior column support with an L5-S1 interbody fusion was protective against failure (p < 0.05). CONCLUSIONS: Acute catastrophic failures involved large-magnitude surgical corrections and likely resulted from high mechanical strain on the pelvic instrumentation. Patients with large corrections may benefit from anterior structural support placed at the most caudal motion segment and multiple rods connecting to more than 2 pelvic fixation points. If failure occurs, salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.

Pediatric Back Pain: A Scoring System to Guide Use of Magnetic Resonance Imaging.

BACKGROUND: The prevalence of back pain in the pediatric population is increasing, and the workup of these patients presents a clinical challenge. Many cases are selflimited, but failure to diagnose a pathology that requires clinical intervention can carry severe repercussions. Magnetic resonance imaging (MRI) carries a high cost to the patient and health care system, and may even require procedural sedation in the pediatric population. The aim of this study was to develop a scoring system based on pediatric patient factors to help determine when an MRI will change clinical management. METHODS: This is a retrospective cohort analysis of consecutive pediatric patients who presented to clinic with a chief complaint of back pain between 2010 and 2018 at single orthopaedic surgery practice. Comprehensive demographic and presentation variables were collected. A predictive model of factors that influence whether MRI results in a change in management was then generated using cross-validation least absolute shrinkage and selection operator logistic regression analysis. RESULTS: A total of 729 patients were included, with a mean age of 15.1 years (range: 3 to 20 y). Of these, 344 (47.2%) had an MRI. A predictive model was generated, with nocturnal symptoms (5 points), neurological deficit (10 points), age (0.7 points per year), lumbar pain (2 points), sudden onset of pain (3.25 points), and leg pain (3.75 points) identified as significant predictors. A combined score of greater than 9.5 points for a given patient is highly suggestive that an MRI will result in a change in clinical management (specificity: 0.93; positive predictive value: 0.92). CONCLUSIONS: A predictive model was generated to help determine when ordering an MRI may result in a change in clinical management for workup of back pain in the pediatric population. The main factors included the presence of a neurological deficit, nocturnal symptoms, sudden onset, leg pain, lumbar pain, and age. Care providers can use these findings to better determine if and when an MRI might be appropriate. LEVEL OF EVIDENCE: Level III-diagnostic study.

Revision Strategies for Harrington Rod Instrumentation: Radiographic Outcomes and Complications.

STUDY DESIGN: Retrospective case series. OBJECTIVE: The purpose of this study is to evaluate the clinical and radiographic outcomes following revision surgery following Harrington rod instrumentation. METHODS: Patients who underwent revision surgery with a minimum of 1-year follow-up for flatback syndrome following Harrington rod instrumentation for adolescent idiopathic scoliosis were identified from a multicenter dataset. Baseline demographics and intraoperative information were obtained. Preoperative, initial postoperative, and most recent spinopelvic parameters were compared. Postoperative complications and reoperations were subsequently evaluated. RESULTS: A total of 41 patients met the inclusion criteria with an average follow-up of 27.7 months. Overall, 14 patients (34.1%) underwent a combined anterior-posterior fusion, and 27 (65.9%) underwent an osteotomy for correction. Preoperatively, the most common lower instrumented vertebra (LIV) was at L3 and L4 (61%), whereas 85% had a LIV to the pelvis after revision. The mean preoperative pelvic incidence-lumbar lordosis mismatch and C7 sagittal vertical axis were 23.7° and 89.6 mm. This was corrected to 8.1° and 28.9 mm and maintained to 9.04° and 34.4 mm at latest follow-up. Complications included deep wound infection (12.2%), durotomy (14.6%), implant related failures (14.6%), and temporary neurologic deficits (22.0%). Eight patients underwent further revision surgery at an average of 7.4 months after initial revision. CONCLUSIONS: There are multiple surgical techniques to address symptomatic flatback syndrome in patients with previous Harrington rod instrumentation for adolescent idiopathic scoliosis. At an average of 27.7 months follow-up, pelvic incidence-lumbar lordosis mismatch and C7 sagittal vertical axis can be successfully corrected and maintained. However, complication and reoperation rates remain high.

Best Practice Guidelines for Assessment and Management of Osteoporosis in Adult Patients Undergoing Elective Spinal Reconstruction.

STUDY DESIGN: Expert consensus study. OBJECTIVE: This expert panel was created to establish best practice guidelines to identify and treat patients with poor bone health prior to elective spinal reconstruction. SUMMARY OF BACKGROUND DATA: Currently, no guidelines exist for the management of osteoporosis and osteopenia in patients undergoing spinal reconstructive surgery. Untreated osteoporosis in spine reconstruction surgery is associated with higher complications and worse outcomes. METHODS: A multidisciplinary panel with 18 experts was assembled including orthopedic and neurological surgeons, endocrinologists, and rheumatologists. Surveys and discussions regarding the current literature were held according to Delphi method until a final set of guidelines was created with over 70% consensus. RESULTS: Panelists agreed that bone health should be considered in every patient prior to elective spinal reconstruction. All patients above 65 and those under 65 with particular risk factors (chronic glucocorticoid use, high fracture risk or previous fracture, limited mobility, and eight other key factors) should have a formal bone health evaluation prior to undergoing surgery. DXA scans of the hip are preferable due to their wide availability. Opportunistic CT Hounsfield Units of the vertebrae can be useful in identifying poor bone health. In the absence of contraindications, anabolic agents are considered first line therapy due to their bone building properties as compared with antiresorptive medications. Medications should be administered preoperatively for at least 2 months and postoperatively for minimum 8 months. CONCLUSION: Based on the consensus of a multidisciplinary panel of experts, we propose best practice guidelines for assessment and treatment of poor bone health prior to elective spinal reconstructive surgery. Patients above age 65 and those with particular risk factors under 65 should undergo formal bone health evaluation. We also established guidelines on perioperative optimization, utility of various diagnostic modalities, and the optimal medical management of bone health in this population.Level of Evidence: 5.

High-Grade Spondylolisthesis in Adults: Current Concepts in Evaluation and Management.

BACKGROUND: Information regarding the treatment of high-grade spondylolisthesis (HGS) in adults has been previously described; however, previous descriptions of the evaluation and surgical management of HGS do not represent more recent and now established approaches. The purpose of the current review is to discuss current concepts in the evaluation and management of patients with HGS. METHODS: Literature review. RESULTS: HGS is diagnosed in up to 11.3% of adults with spondylolisthesis and typically presents as nonspecific lower back pain. Regarding evaluation, a thorough history and physical examination should be performed, which may help predict the presence of HGS. Diagnostic imaging, and specifically the use of spino-pelvic parameters, are now commonly implicated in guiding treatment course and prognosis. When surgical intervention is indicated, surgical approaches include in situ fusion variations, reduction and partial reduction with fusion, and vertebrectomy. Although the majority of studies suggest improvements with these approaches, the literature is limited by a low level of evidence with regards to the superiority of one technique when compared with others. CONCLUSIONS: HGS is a unique cause of low back pain in adults that carries considerable morbidity, but rarely presents with neurologic symptoms. Although the definitions, classifications, and methods of diagnosis of this spinal deformity have been established and accepted, the ideal surgical management of this deformity remains highly debated. Fusion in situ techniques are often technically easier to perform and provide lower risk of neurologic complications, whereas reduction and fusion techniques offer greater restoration of global spino-pelvic balance. Preoperative spino-pelvic parameters may have utility in assisting in procedural selection; however, future, higher-quality and longer-term studies are warranted to determine the optimal surgical intervention among the widely available techniques currently used, and to better define the indications for these interventions.

Sagittal Balance in Adult Idiopathic Scoliosis.

STUDY DESIGN: A narrative review article study. OBJECTIVE: The objective of this study was to highlight guiding principles and challenges faced with addressing sagittal alignment in patients with adult idiopathic scoliosis (AIS) and to discuss effective surgical strategies based upon our clinical experience. SUMMARY OF BACKGROUND DATA: Previous research and guidelines for the treatment of AIS have focused on the correction of spinal deformity in the coronal and axial planes. Failure to address sagittal deformity has been associated with numerous adverse clinical outcomes. METHODS: This is a review of the current body of literature and a description of the rod derotation surgical technique for correction in the sagittal plane. RESULTS: Several studies have offered general goals for postoperative radiographic measures in the sagittal plane for patients with AIS. However, these guidelines are evolving as diagnostic and therapeutic modalities continue to improve. The rod derotation surgical technique through differential metal rods is one method to potentially address sagittal balance in AIS. CONCLUSIONS: Alignment in the sagittal plane is a unique challenge facing surgeons for patients with AIS. Further research with an assessment of functional outcomes and longer follow-up is needed to more precisely guide treatment principles. LEVEL OF EVIDENCE: Level IV.

Sagittal spinopelvic malalignment in degenerative scoliosis patients: isolated correction of symptomatic levels and clinical decision-making.

BACKGROUND: This study aims to determine if (1) loss of lumbar lordosis (LL), often associated with degenerative scoliosis (DS), is structural or rather largely due to positional factors secondary to spinal stenosis; (2) only addressing the symptomatic levels with a decompression and posterolateral fusion in carefully selected patients will result in improvement of sagittal malalignment; and (3) degree of sagittal plane correction achieved with such a local fusion could be predicted by routine pre-operative imaging. METHODS: A retrospective study design with prospectively collected imaging data of a consecutive series of surgically treated DS patients who underwent decompression and instrumented fusion at only symptomatic levels was performed. Pre- and post-operative plain radiographs and pre-operative magnetic resonance imaging (MRIs) of the spinopelvic region were analyzed. LL, pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) were assessed in all patients. As a requirement for the surgical strategy, all patients presented with a pre-operative PI-LL mismatch greater than 10°. Post-operative complications were assessed. RESULTS: Pre-operative MRIs and lumbar extension radiographs revealed a mean LL of 42° (range 10-66°) and 48° (range 20-74°), respectively, in 68 patients (mean follow-up 29 months). LL post-operatively was corrected to a mean PI-LL of 10°. Of patients who achieved PI-LL mismatch within 10o on their pre-operative extension lateral lumbar radiographs, 62.5% were able to maintain a PI-LL mismatch within 10° on their initial post-operative films. Only 37.5% were not able to achieve that mismatch on extension radiographs (p = 0.001, OR = 9.58). Similarly, 54.2% were able to achieve a PI-LL < 10° on initial post-operative radiographs, when pre-operative MRI revealed a PI-LL mismatch within 10°. In contrast, only 20.5% achieved that goal post-operatively if their mismatch was greater than 10o on their MRI (p = 0.003, OR = 4.25). CONCLUSION: With a decompression and instrumented fusion of only the symptomatic levels in symptomatic DS patients, we were able to achieve a PI-LL mismatch to within 10°. The loss of LL observed pre-operatively may be largely positional rather than structural. The amount of LL correction observed immediately after surgery can be predicted from pre-operative lumbar extension radiographs and supine sagittal MRI.

Free Vascularized Fibular Strut Autografts to the Lumbar Spine in Complex Revision Surgery: A Report of Two Cases.

This case report presents two patients who underwent fibular strut grafting for complex revisions of previous lumbar spine arthrodeses. A case review of the Electronic Medical Record at the index institution was performed to evaluate the timeline of events of the two patients who underwent fibular strut grafting for complex revisions of previous lumbar spine arthrodesis, including imaging studies, progress notes, and laboratory results. One patient had developed chronic L3 vertebral body osteomyelitis from a prior fibular allograft and instrumentation placed for a traumatic burst fracture. The second patient had a severe scoliosis recalcitrant to prior arthrodeses in the context of Marfan syndrome and a persistent L4-5 pseudarthrosis. Both patients underwent free vascularized fibular autograft revision arthrodeses. At most recent long-term follow-up, both patients had improved clinically and neither had required further revision. The use of free vascularized fibular grafting is an excellent option for a variety of spinal indications, and these two reports indicate that the technology may have an indication for use after multiple failed surgeries for osteomyelitis or correction of a multi-level large spinal deformity secondary to Marfan syndrome.

Late Fracture After Long Spinal Fusion for Idiopathic Scoliosis: A Case Report.

STUDY DESIGN: Case report. OBJECTIVES: To report a case of late atraumatic fracture of a long spinal fusion for idiopathic scoliosis 37 years after removal of instrumentation and review the literature on this complication. SUMMARY OF BACKGROUND DATA: Late fracture of a long spinal fusion performed for idiopathic scoliosis is rare, with only several cases reported in the literature. METHODS: The authors report a case of atraumatic fracture of a long fusion mass in a 55-year-old woman who underwent spinal fusion with Harrington rods at age 14 years with Harrington rod removal at age 18 years. She subsequently developed flat-back syndrome at age 49 years and underwent L3-4, L4-5, and L5-S1 Smith-Peterson osteotomies and posterolateral segmental instrumentation fusion from T12 to pelvis. She developed acute-onset mid-thoracic pain after a minor twisting injury without radiation or neurologic deficit, and was found on magnetic resonance imaging to have a fracture through the fusion mass at T6-7 with increased activity at this location on bone scan. RESULTS: The patient failed conservative treatment with a high custom-molded brace and underwent posterior segmental spinal instrumentation and fusion from T2 to the previous instrumentation at L2 with autograft and allograft. She had immediate improvement of back pain postoperatively and has recovered well from the surgery. CONCLUSIONS: Late fracture through a long fusion mass is a rare long-term complication of spine fusion for idiopathic scoliosis. In this case report, we report successful treatment of a fracture with a long lever arm of a solid posterior fused spine with posterior instrumented fusion multiple levels above and below the fracture.

Instrumentation-related complications of multilevel fusions for adult spinal deformity patients over age 65: surgical considerations and treatment options in patients with poor bone quality.

STUDY DESIGN: Retrospective follow-up of patients over the age of 65 with a minimum of five-level fusions. OBJECTIVE: To determine the effect on outcomes of long constructs in patients with poor bone stock, and to review surgical techniques used in patients with poor bone stock. SUMMARY OF BACKGROUND DATA: Scoliotic deformities in patients with poor bone stock require alterations in both the surgical technique and preoperative planning. To our knowledge, complications of long constructs in poor bone stock have not been specifically reported. METHOD: Patients over the age of 65 that underwent a minimum of five-level fusion over a 5-year period were reviewed. We reviewed both operative reports and clinic notes and recorded both early and late complications. RESULTS: Early complications included pedicle fractures and compression fractures with an overall rate of 13%. Late complications included pseudarthroses with instrumentation failure, adjacent level disc degeneration with herniation, compression fractures, and progressive kyphosis. Progressive junctional kyphosis occurred in 26% of patients. CONCLUSIONS: Spinal stabilization surgery in patients with poor bone stock is associated with high complication rates. Complications such as progressive kyphosis adjacent to the fusion are difficult to address with instrumentation alone.

The superior mesenteric artery syndrome in patients with spinal deformity.

STUDY DESIGN: A retrospective review. OBJECTIVE: To determine the incidence of the superior mesenteric artery syndrome (SMAS) after surgical correction for scoliosis and if it is influenced by newer derotation/translation surgical systems. SUMMARY OF BACKGROUND DATA: The SMAS is a known complication after surgery. METHOD: Of 2939 charts reviewed, 17 patients between 1960 and 2002 matched inclusion criteria. RESULTS: Our incidence of the SMAS was 0.5%. Onset of symptoms was 7.2 days. Several scoliosis diagnoses were included in the study group. Instrumentation that was used included: nondistraction systems (n = 14), Harrington rod with body cast (n = 1), Luque rod with sublaminar wires (n = 1), and casted in situ posterior spinal fusion (n = 1). Before surgery, 10 of 17 patients weighed less than the 50th percentile. Mean preoperative BMI was 18.6 kg/cm/cm. Postoperative height gain averaged 3.175 cm, and weight loss at onset of symptoms averaged 4.5 kg. There were 14 patients who required nasogastric suction for an average duration of 10.2 days, 11 required hyperalimentation, and 5 concurrently received hyperalimentation with enteric feeding. The SMAS recurred in 2 patients. CONCLUSIONS: Postoperative weight loss appears to be more important for the development of the SMAS than asthenic body type. Newer derotation/translation corrective techniques have not eliminated the SMAS. Gastrointestinal imaging is indicated when nausea and vomiting occur 6-12 days after surgery, associated with early satiety and normal bowel sounds. Decompression and nutritional support remain the mainstays of treatment.

Evaluation and management of high-grade spondylolisthesis in adults.

STUDY DESIGN: A retrospective review was performed on 21 adult patients surgically treated with high-grade spondylolisthesis (Grade III, IV, or V). Additionally, the natural history, classification, and surgical alternatives for high-grade spondylolisthesis in the adult are discussed through literature review. OBJECTIVES: The purpose of this article is to review the clinical and radiographic outcomes of surgical treatment of high-grade spondylolisthesis in the adult from a single institution. The natural history and treatment options for these adults are described in this review. SUMMARY OF BACKGROUND DATA: High-grade spondylolisthesis is typically diagnosed and treated in the child or adolescent. Most patients with high-grade spondylolisthesis received surgical treatment during their adolescence. Some patients, however, remain minimally symptomatic for life without surgery. Little has been written on the natural history or treatment of adults with high grades of spondylolisthesis. Most of the published reports on the surgical treatment of high-grade spondylolisthesis pertain to skeletally immature patients and maybe include a few adults in their series. Nonetheless, the different techniques of surgical treatment for high-grade spondylolisthesis that have been described in these studies can help the spinal surgeon in treatment options for this rare but difficult spinal deformity. METHODS: A literature review of the published manuscripts on the treatment of high-grade spondylolisthesis was performed with particular attention to the natural history and surgical treatment involving adult patients. Adult patients (older than 21 years) with high-grade spondylolisthesis treated surgically were retrospectively reviewed. Patients' clinical charts and radiographs were reviewed before and after surgery. Determination of fusion success, clinical outcome, and complications were performed. RESULTS: Twenty-one consecutive adults with high-grade spondylolisthesis who underwent lumbar spinal surgery were review retrospectively between 1990 and 2004. There were 13 females and 8 males with an average age of 35 years (range, 21-68 years). The average follow-up was 6.6 years. There were 11 Grade III, 6 Grade IV, and 4 Grade V slips, including 4 acquired and 17 developmental spondylolistheses. There were no pseudarthroses or significant instrumentation failures. There was 1 case of a complete cauda equina syndrome on a patient with preoperative symptoms of an incomplete cauda equina syndrome. CONCLUSIONS: Adult patients with high-grade spondylolisthesis not responding to nonoperative treatment can be stabilized in situ with posterior instrumentation from L4 to S1. The use of adjunctive fixation with iliac screws and/or transvertebral screws is recommended for the adult patient, particularly in revision or unstable cases. Reduction of the slipped vertebrae remains controversial for all grades of spondylolisthesis and more so for the adult patient. Partial reduction of the slip angle, decreasing the lumbosacral kyphosis, should be considered if significant sagittal malalignment is present or to improve arthrodesis success. Anterior column support should be performed, particularly when reduction has been obtained. Anterior column support can be performed, anteriorly or posteriorly, either by using inter vertebral body structural strut support or with a transsacral fibular dowel to improve stability and success of arthrodesis.

Long structural allografts in the treatment of anterior spinal column defects.

A retrospective study of 41 patients who had anterior spinal column reconstruction using long-segment allografts between 1983 and 1998 is reported. A long-segment allograft was defined as an allograft strut that replaces a vertebral body or approximates the height of the adjacent vertebral body for the thoracolumbar or lumbar spine, or more than two vertebral bodies for the cervical or cervicothoracic spine. Forty of the 41 patients had successful anterior strut grafting with radiographic evidence of allograft incorporation at the last followup with the majority of patients having radiographic evidence of incorporation by 6 months. There where three early complications related to the allograft (two end plate fractures and one repeated cervical spine allograft dislodgment) and one late complication associated with the posterior adjunct instrumentation unrelated to the allograft (degenerative lumbar stenosis). The only procedural complication was a deep venous thrombosis and a resultant nonfatal pulmonary embolus. No allografts fractured or collapsed. These data suggest that long-segment anterior allografts work exceptionally well in maintaining vertebral height and structural integrity in numerous pathologic deformities including traumatic and infectious etiologies.