What Are the Indications for Spinal Fusion Surgery in Scheuermann Kyphosis?

BACKGROUND: Surgical indications for Scheuermann kyphosis are variable. We sought to evaluate the characteristics of patients undergoing operative versus nonoperative treatment of Scheuermann kyphosis to better understand current practices and the factors which contribute to the decision for surgical management. METHODS: Multicenter prospective cohort study. We evaluated consecutive patients presenting with Scheuermann kyphosis. Patients underwent either surgical or nonoperative management according to surgeon and patient discretion. Preoperative patient-reported outcome measures (Scoliosis Research Society and Spinal Appearance Questionnaire scores), demographics, and radiographic characteristics were assessed. RESULTS: Overall, 150 patients with Scheuermann kyphosis were enrolled, with 77 choosing nonoperative treatment and 73 treated operatively. Compared with the nonoperative cohort, patients treated operatively were older (16.3±2.0 vs. 15.1±2.2, P=0.0004), and had higher body mass index (26.3±7.2 vs. 22.7±6.5, P=0.003), had greater T2-T12 kyphosis (71±14 degrees vs. 61±12 degrees, P<0.001), increased pelvic incidence (46 vs. 41 degrees, P=0.03) and pelvic tilt (10 vs. 3 degrees, P=0.03). There was no detected difference in maximal sagittal Cobb angle in the operative versus nonoperative patients (73±11 vs. 70±12 degrees, P=0.11). Functionally, the operative patients had worse Scoliosis Research Society pain scores (3.7±0.9 vs. 4.1±0.7, P=0.0027) and appearance scores (2.9±0.7 vs. 3.4±0.8, P <0.0001). CONCLUSIONS: Patients undergoing surgical management of Scheuermann disease were more likely to have large body mass index and worse pain scores. Other factors beyond radiographic measurement likely contribute to the decision for surgical management of Scheuermann kyphosis. LEVEL OF EVIDENCE: Level II.

Oswestry Disability Index: Is Telephone Administration Valid?

Background: The Oswestry Disability Index (ODI) is among the most widely used patient reported outcome measures for the assessment of spinal conditions. Traditionally, the ODI has been administered in outpatient clinics on a face-to-face basis, which can be expensive and time consuming. Furthermore, the percentage of patients lost to clinical follow-up is high, particularly after 2-5 years. Thus, telephonic administration of the ODI, if valid, could be a convenient way of capturing patient outcomes and increasing follow-up rates. The objective of this study was to validate telephonic administration of the ODI compared to face-to-face administration. Methods: A convenience sample of individuals with and without back pain in an academic medical center were recruited for this study. Face-to-face administration of the ODI was completed and retested 24 hours later via phone. Test-retest reliability was determined by calculating the intraclass correlation coefficient. Results: 22 individuals completed the ODI questionnaire face-to-face, then via telephone 24 hours later. There was a mean 2% (± 3) intra-rater ODI score difference (range: 0% to 12%). The intraclass correlation coefficient overall was 0.98 (95% CI: 0.96, 0.99, p<0.001) with a range of 0.95 to 1.0, revealing near-perfect test-retest reliability. Conclusions: Administration of the ODI questionnaire over the phone has excellent test-retest reliability when compared to face-to-face administration. Telephone administration is a convenient and reliable option for obtaining follow-up outcomes data. Clinical Relevance: Telephonic administration of the ODI is scientifically valid, and should be an accepted method of data collection for state-level and national-level outcomes projects.

Implant Density at the Apex Is More Important Than Overall Implant Density for 3D Correction in Thoracic Adolescent Idiopathic Scoliosis Using Rod Derotation and En Bloc Vertebral Derotation Technique.

STUDY DESIGN: Biomechanical analysis of 3D correction and bone-screw forces through numerical simulations of scoliosis instrumentation with different pedicle screw patterns. OBJECTIVE: To analyze the effect of different screw densities and distributions on 3D correction and bone-screw forces in adolescent idiopathic scoliosis (AIS) instrumentation. SUMMARY OF BACKGROUND DATA: Instrumentation constructs with various numbers of pedicle screws and patterns have been proposed for thoracic AIS instrumentation. However, systematic biomechanical studies have not yet been completed on the appropriate screw patterns for optimal 3D correction. METHODS: Patient-specific biomechanical models of the spine were created for 10 AIS cases (Lenke 1). For each case, surgical instrumentation patterns were computationally simulated using respectively a reference screw pattern (two screws per level fused) and six alternative screw patterns with fewer screws. Simulated surgical maneuvers and model definition were unchanged between simulations except the number and distribution of screws. 3D correction and bone-screw forces were compared. RESULTS: A total of 140 posterior instrumentations were computationally simulated. Mean corrections in the coronal and sagittal planes with alternative screw patterns were within 4° to the reference pattern. Increasing screw density in the apical region from one to two screws per level improved percent apical vertebral rotation (AVR) correction (r = 0.887, P < 0.05). Average bone-screw force associated with the reference screw pattern was 243N ±â€Š54N and those with the alternative screw patterns were 11% to 48% lower. CONCLUSION: Compared with the reference maximal screw density pattern, alternative screw patterns allowed similar corrections in the coronal and sagittal planes. AVR correction was strongly correlated with screw density in the apical region; AVR correction varied significantly with screw patterns of the same overall screw density when an en bloc vertebral derotation technique was simulated. High screw density tended to overconstrain the instrumented spine and resulted in higher forces at the bone-screw interface. LEVEL OF EVIDENCE: N/A.

Biomechanical effect of pedicle screw distribution in AIS instrumentation using a segmental translation technique: computer modeling and simulation.

BACKGROUND: Efforts to select the appropriate number of implants in adolescent idiopathic scoliosis (AIS) instrumentation are hampered by a lack of biomechanical studies. The objective was to biomechanically evaluate screw density at different regions in the curve for AIS correction to test the hypothesis that alternative screw patterns do not compromise anticipated correction in AIS when using a segmental translation technique. METHODS: Instrumentation simulations were computationally performed for 10 AIS cases. We simulated simultaneous concave and convex segmental translation for a reference screw pattern (bilateral polyaxial pedicle screws with dorsal height adjustability at every level fused) and four alternative patterns; screws were dropped respectively on convex or concave side at alternate levels or at the periapical levels (21 to 25% fewer screws). Predicted deformity correction and screw forces were compared. RESULTS: Final simulated Cobb angle differences with the alternative screw patterns varied between 1° to 5° (39 simulations) and 8° (1 simulation) compared to the reference maximal density screw pattern. Thoracic kyphosis and apical vertebral rotation were within 2° of the reference screw pattern. Screw forces were 76 ± 43 N, 96 ± 58 N, 90 ± 54 N, 82 ± 33 N, and 79 ± 42 N, respectively, for the reference screw pattern and screw dropouts at convex alternate levels, concave alternate levels, convex periapical levels, and concave periapical levels. Bone-screw forces for the alternative patterns were higher than the reference pattern (p < 0.0003). There was no statistical bone-screw force difference between convex and concave alternate dropouts and between convex and concave periapical dropouts (p > 0.28). Alternate dropout screw forces were higher than periapical dropouts (p < 0.05). CONCLUSIONS: Using a simultaneous segmental translation technique, deformity correction can be achieved with 23% fewer screws than maximal density screw pattern, but resulted in 25% higher bone-screw forces. Screw dropouts could be either on the convex side or on the concave side at alternate levels or at periapical levels. Periapical screw dropouts may more likely result in lower bone-screw force increase than alternate level screw dropouts.

Current Evidence Regarding Diagnostic Imaging Methods for Pediatric Lumbar Spondylolysis: A Report From the Scoliosis Research Society Evidence-Based Medicine Committee.

BACKGROUND: Spondylolysis is common among the pediatric population, yet no formal systematic literature review regarding diagnostic imaging has been performed. The Scoliosis Research Society (SRS) requested an assessment of the current state of peer reviewed evidence regarding pediatric spondylolysis. METHODS: Literature was searched professionally and citations retrieved. Abstracts were reviewed and analyzed by the SRS Evidence-Based Medicine Committee. Level I studies were considered to provide Good Evidence for the clinical question. Level II or III studies were considered Fair Evidence. Level IV studies were considered Poor Evidence. From 947 abstracts, 383 full texts reviewed. Best available evidence for the questions of diagnostic methods was provided by 27 studies: no Level I sensitivity/specificity studies, five Level II and two Level III evidence, and 19 Level IV evidence. RESULTS: Pain with hyperextension in athletes is the most widely reported finding in history and physical examination. Plain radiography is considered a first-line diagnostic test for suspected spondylolysis, but validation evidence is lacking. There is consistent Level II and III evidence that pars defects are detected by advanced imaging in 32% to 44% of adolescents with spondylolysis based on history and physical. Level III evidence that single-photon emission computed tomography (SPECT) is superior to planar bone scan and plain radiographs but limited by high rates of false-positive and false-negative results and by high radiation dose. Computed tomography (CT) is considered the gold standard and most accurate modality for detecting the bony defect and assessment of osseous healing but exposes the pediatric patient to ionizing radiation. Magnetic resonance imaging (MRI) is reported to be as accurate as CT and useful in detecting early stress reactions of the pars without a fracture. CONCLUSION: Plain radiographs are widely used as screening tools for pediatric spondylolysis. CT scan is considered the gold standard but exposes the patient to a significant amount of ionizing radiation. Evidence is fair and promising that MRI is comparable to CT.

Adolescent Idiopathic Scoliosis Thoracic Volume Modeling: The Effect of Surgical Correction.

BACKGROUND: Scoliosis has been shown to have detrimental effects on pulmonary function, traditionally measured by pulmonary function tests, which is theorized to be correlated to the distortion of the spine and thorax. The changes in thoracic volume with surgical correction have not been well quantified. This study seeks to define the effect of surgical correction on thoracic volume in patients with adolescent idiopathic scoliosis. METHODS: Images were obtained from adolescents with idiopathic scoliosis enrolled in a multicenter database (Prospective Pediatric Scoliosis Study). A convenience sample of patients with Lenke type 1 curves with a complete data set meeting specific parameters was used. Blender v2.63a software was used to construct a 3-dimensional (3D) computational model of the spine from 2-dimensional calibrated radiographs. To accomplish this, the 3D thorax model was deformed to match the calibrated radiographs. The thorax volume was then calculated in cubic centimeters using Mimics v15 software. RESULTS: The results using this computational modeling technique demonstrated that surgical correction resulted in decreased curve measurement as determined by Cobb method, and increased postoperative thoracic volume as expected. Thoracic volume significantly increased by a mean of 567 mm (P<0.001). The percent change in thoracic volume after surgical correction averaged 40% (range, 3% to 87%). The smaller the baseline volume, the greater the change in volume postoperatively (r=-0.86).Evaluation of postoperative data demonstrated that spinal curve measurement as determined by Cobb method was significantly reduced from a mean of 69 degrees (range, 50 to 96 degrees) preoperatively to 27 degrees (range, 13 to 33 degrees) postoperatively (P<0.001). CONCLUSIONS: This pilot study demonstrates methodologic plausibility for measuring 3D changes in thoracic volumes using 2-dimensional imaging. This is an assessment of the novel modeling technique, to be used in larger future studies to assess clinical significance. LEVEL OF EVIDENCE: Level 3-retrospective comparison of prospectively collected data.

Sacral bone mineral density (BMD) assessment using opportunistic CT scans.

This study seeks to establish a method for opportunistic evaluation of sacral bone mineral density. This is a retrospective review of 109 scans from 109 patients who had renal-protocol computed tomography (CT) scans performed for any indication during a 3-month period at a single academic institution in 2014. In the collected CT scans, sacral CT-attenuation in multiple regions of interest (ROI) was compared to the L1 CT-attenuation, an internal reference standard, to determine if a correlation existed. The sacral ROI were analyzed to determine regions of higher and lower attenuation. All sacral ROI had strong correlations with lumbar spine attenuation values, and these values became even stronger when transitional vertebrae were excluded. Sacral attenuation values varied predictably by location, and matched relationships were shown by prior volumetric bone mineral density studies. We conclude that sacral CT-attenuation can be used in opportunistic CT scans to determine sacral bone mineral density. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:160-166, 2017.

What would be the annual cost savings if fewer screws were used in adolescent idiopathic scoliosis treatment in the US?

OBJECTIVE: There is substantial heterogeneity in the number of screws used per level fused in adolescent idiopathic scoliosis (AIS) surgery. Assuming equivalent clinical outcomes, the potential cost savings of using fewer pedicle screws were estimated using a medical decision model with sensitivity analysis. METHODS: Descriptive analyses explored the annual costs for 5710 AIS inpatient stays using discharge data from the 2009 Kids' Inpatient Database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality), which is a national all-payer inpatient database. Patients between 10 and 17 years of age were identified using the ICD-9-CM code for idiopathic scoliosis (737.30). All inpatient stays were assumed to represent 10-level fusions with pedicle screws for AIS. High screw density was defined at 1.8 screws per level fused, and the standard screw density was defined as 1.48 screws per level fused. The surgical return for screw malposition was set at $23,762. A sensitivity analysis was performed by varying the cost per screw ($600-$1000) and the rate of surgical revisions for screw malposition (0.117%-0.483% of screws; 0.8%-4.3% of patients). The reported outcomes include estimated prevented malpositioned screws (set at 5.1%), averted revision surgeries, and annual cost savings in 2009 US dollars, assuming similar clinical outcomes (rates of complications, revision) using a standard- versus high-density pattern. RESULTS: The total annual costs for 5710 AIS hospital stays was $278 million ($48,900 per patient). Substituting a high for a standard screw density yields 3.2 fewer screws implanted per patient, with 932 malpositioned screws prevented and 21 to 88 revision surgeries for implant malposition averted, and a potential annual cost savings of $11 million to $20 million (4%-7% reduction in the total cost of AIS hospitalizations). CONCLUSIONS: Reducing the number of screws used in scoliosis surgery could potentially decrease national AIS hospitalization costs by up to 7%, which may improve the safety and efficiency of care. However, such a screw construct must first be proven safe and effective.

How Much Work Effort is Involved in Minimally Invasive Sacroiliac Joint Fusion?

BACKGROUND: Minimally invasive sacroiliac joint fusion is increasing significantly. Starting January 1, 2015, it has a category I CPT code. The current RVU for this procedure is not equal to the amount of work involved. There is not a published RUC validated survey to establish the work effort of MI SI fusion. Our hospital system has been doing this procedure for 4 years and has been tracking surgeon time through a commercial tracking system (Navicare). Our study looks at time utilization for performance of MI SI joint fusion and a comparator of primary lumbar discectomy (PLD), presumably similar in time and work effort. METHODS: This study was a retrospective review of prospectively collected data using Navicare. The data for 3 surgeons who perform MI SI joint fusion and lumbar discectomies from January 1, 2013 through November 30, 2014 was retrieved. Surgeon room time was identified as the time the patient entered the OR to the time they exited the OR. This was used as opposed to skin to skin time seen in similar studies as it was more accurately and consistently recorded in the medical record. Mean and standard deviations were then compared using student's t-test. RESULTS: In 50 primary MI SI joint fusions, the average in-room time was 112 minutes (SD=23). In 89 cases of PLD, the average in-room time was 119 minutes (SD=26). When comparing mean in-room times, MI SI and PLD were not statistically significantly different (p=0.135, 2-tailed t-test). Post-operative work effort was found to be greater for MI SI joint fusion than PLD. CONCLUSIONS / LEVEL OF EVIDENCE: Surgical time was found to be comparable between MI SI joint fusion and PLD, while work effort was found to be greater for MI SI joint fusion. This signifies at a minimum an equal RVU for PLD should be used for MI SI joint fusion. This study was approved by the Institutional Review Board at the University of Minnesota. LEVEL OF EVIDENCE: 3.

Current Evidence Regarding the Surgical and Nonsurgical Treatment of Pediatric Lumbar Spondylolysis: A Report from the Scoliosis Research Society Evidence-Based Medicine Committee.

STUDY DESIGN: Structured literature review. OBJECTIVES: The Scoliosis Research Society requested an assessment of the current state of peer-reviewed evidence regarding pediatric spondylolysis with the goal of identifying both what is really known and what research remains essential to further understanding. SUMMARY OF BACKGROUND DATA: Spondylolysis is common among children and adolescents and no formal synthesis of the published literature regarding treatment has been previously performed. METHODS: A comprehensive literature search was performed. The researchers reviewed abstracts and analyzed by committee data from included studies. From 947 initial citations with abstract, 383 articles underwent full text review. The best available evidence for clinical questions regarding surgical and nonsurgical treatment was provided by 58 included studies. None of the studies were graded as level I or level II evidence. Two of the studies were graded as level III evidence. Fifty-six of the studies were graded as level IV evidence. No level V (expert opinion) studies were included in the final list. RESULTS: Although natural history studies suggest a benign, relatively asymptomatic course for spondylolysis in most patients, both nonsurgical and surgical treatment series suggest that a substantial number of patients present with pain and activity limitations attributed to spondylolysis. Pain resolution and return to activity are common with both nonsurgical and surgical treatment (80% to 85%, respectively). Although it is implied that most surgically treated patients have failed nonsurgical treatment, the specific treatment modalities and duration required before failure is declared are not well defined. There is insufficient evidence to know which patients will benefit from specific treatment modalities (both nonsurgical and surgical). CONCLUSIONS: Because of the preponderance of uncontrolled case series and the lack of comparative studies, only low-quality evidence is available to guide the treatment of pediatric spondylolysis.

Current Evidence Regarding the Etiology, Prevalence, Natural History, and Prognosis of Pediatric Lumbar Spondylolysis: A Report from the Scoliosis Research Society Evidence-Based Medicine Committee.

STUDY DESIGN: Structured literature review. OBJECTIVES: To assess the current state of evidence as a first step in the development of practice guidelines for pediatric spondylolysis. SUMMARY OF BACKGROUND DATA: Progress in published medical knowledge, changes in societal expectations, and developments in health care economics have led medical organizations to develop evidence-based documents and products. METHODS: A comprehensive literature search for pediatric spondylolysis was performed with the assistance of a medical librarian. The authors reviewed citations and abstracts. Abstracts were reviewed for exclusions and data from included studies were analyzed by committee. A total of 44 articles provided the best available evidence for the questions of etiology, prevalence, natural history, and prognosis: 9 were graded as level I evidence, 23 were level II, 3 were level III, and 9 were level IV. No level V studies were included in the final list. RESULTS: There is good evidence that pediatric lumbar spondylolysis is an acquired fracture of the pars interarticularis that can occur unilaterally or bilaterally. Evidence shows that when chronic, bilateral pars defects develop, 43% to 74% of patients will progress to grade 1 or 2 spondylolisthesis. In addition, unilateral, incomplete, and early lesions can obtain bony union. With or without bony union or spondylolisthesis, short-term symptom resolution is the norm. Long-term prognosis is less clear, but there is fair evidence that most patients will have lumbar symptoms compared with the general population. There is also fair evidence that some patients will develop significant symptoms as adults and will undergo surgical treatment. There is insufficient knowledge to predict which patients will continue to do well in the long term with conservative or no treatment and which patients will develop symptoms significant enough to warrant early intervention. CONCLUSIONS: The current medical literature provides fair to good evidence for clinically relevant questions regarding the etiology, prevalence, natural history, and prognosis of pediatric spondylolysis.

Reprocessed arthroscopic shavers: evaluation of sharpness and function in a cadaver model.

This study was designed to test limited arthroscopic shaver reuse following reprocessing and to compare the functional performance between new and reprocessed arthroscopic shavers in arthroscopic procedures using fresh cadaveric knees. A trial using arthroscopic procedures (menisectomy, synovectomy, and debridements) was conducted by experienced surgeons using cadaveric knees to determine whether the surgeons could correctly identify reprocessed shavers. Thirty-nine shavers were tested; the surgeons were given both new and reprocessed shavers. Thirteen of the 39 shavers were new and 26 were reprocessed (13 of which had also been sharpened). The surgeons were asked to assess whether each shaver was new or reprocessed and to indicate whether the shaver was functional or not. Cadaveric shavers were subsequently used in an engineering test developed to measure shaver blade sharpness. Comparisons in sharpness were made between new and reprocessed cadaveric shaver blades. The success rate in identifying reprocessed shavers was determined to be 42% (11 of 26), with an upper confidence bound of 60%, demonstrating that the ability to detect a reprocessed shaver is no better than chance (50%), with a margin of error of 10% (P=.0328). In addition, engineering sharpness testing demonstrated that new and reprocessed cadaveric blades exhibit equivalent sharpness. Surgeons were unable to distinguish reprocessed arthroscopic shavers that passed acceptance tests from new shavers based on functional characteristics. This outcome is not unexpected due to the fact that engineering testing of shaver blades used in the study indicated that they exhibited similar sharpness.

Utilization of Minimally Invasive Surgical Approach for Sacroiliac Joint Fusion in Surgeon Population of ISASS and SMISS Membership.

INTRODUCTION: The sacroiliac joint (SIJ) may be a source of chronic low back pain in 15 -22% of patients. Over the past four years MIS is an emerging standard of care for SI joint fusion. The International Society for the Advancement of Spine Surgery (ISASS) and Society for Minimally Invasive Spine Surgery (SMISS) conducted a survey of their members to examine current preferences in surgeon practice of MIS SI fusion. METHODS: To qualify for survey participation, the surgeon had to perform at least one open or MIS SIJ fusion procedure between 2009 and 2012. All surgeons were instructed to review their records. This included the number of surgical procedures performed annually from 2009-2012, site of service where each procedure was commonly performed, and average length of stay for each approach. RESULTS: Twenty four percent (121/500) of the eligible members participated in this survey. This survey revealed that the percentage of MIS procedures increased from 39% in 2009 to over 87% in 2012. The survey showed a significant increase in average number of MIS surgeries and a significant difference between open and MIS surgeries in 2012 (p<0.0001). In addition, 80% of the survey respondents indicated a lack of preference toward open approach if that was the only available option. CONCLUSIONS: According to performed survey, MIS SIJ fusion is preferred over open technique. Incorporation of the MIS technique into the spine surgeon's specter of skills would allow an increased number of surgical options as well as possible increase in outcome quality.

Minimally invasive versus open sacroiliac joint fusion: are they similarly safe and effective?

BACKGROUND: The sacroiliac joint has been implicated as a source of chronic low back pain in 15% to 30% of patients. When nonsurgical approaches fail, sacroiliac joint fusion may be recommended. Advances in intraoperative image guidance have assisted minimally invasive surgical (MIS) techniques using ingrowth-coated fusion rods; however, how these techniques perform relative to open anterior fusion of the sacroiliac joint using plates and screws is not known. QUESTIONS/PURPOSES: We compared estimated blood loss (EBL), surgical time, length of hospital stay (LOS), and Oswestry Disability Index (ODI) between patients undergoing MIS and open sacroiliac joint fusion. METHODS: We retrospectively studied 63 patients (open: 36; MIS: 27) who underwent sacroiliac joint fusion with minimum 1-year followup at our institution from 2006 to 2011. Of those, 10 in the open group had incomplete records. All patients had sacroiliac joint dysfunction confirmed by image-guided intraarticular anesthetic sacroiliac joint injection and had failed nonoperative treatment. Patients were matched via propensity score, adjusting for age, sex, BMI, history of spine fusion, and preoperative ODI scores, leaving 22 in each group. Nine patients were not matched. We reviewed patient medical records to obtain EBL, length of surgery, LOS, and pre- and postoperative ODI scores. Mean followup was 13 months (range, 11-33 months) in the open group and 15 months (range, 12-26 months) in the MIS group. RESULTS: Patients in the open group had a higher mean EBL (681 mL versus 41 mL, p < 0.001). Mean surgical time and LOS were shorter in the MIS group than in the open group (68 minutes versus 128 minutes and 3.3 days versus 2 days, p < 0.001 for both). With the numbers available, mean postoperative ODI scores were not different between groups (47% versus 54%, p = 0.272). CONCLUSIONS: EBL, surgery time, and LOS favored the MIS sacroiliac fusion group. With the numbers available, ODI scores were similar between groups, though the study size was relatively small and it is possible that the study was underpowered on this end point. Because the implants used for these procedures make assessment of fusion challenging with available imaging techniques, we do not know how many patients' sacroiliac joints successfully fused, so longer followup and critical evaluation of outcomes scores over time are called for. LEVEL OF EVIDENCE: Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Are More Screws Better? A Systematic Review of Anchor Density and Curve Correction in Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Systematic review of clinical studies. OBJECTIVES: To critically evaluate existing literature to determine whether increased anchor or implant density (screws, wires, and hooks per level fused) results in improved curve correction for adolescent idiopathic scoliosis (AIS) surgery. SUMMARY OF BACKGROUND DATA: Wide variability exists in the number of screws used for AIS surgery. High numbers of pedicle screws are increasingly used, but there is limited evidence to support this as best practice. METHODS: Online English-language databases were searched to identify articles addressing anchor density. Articles were reviewed for anchor type/number, radiographic measures, and patient-reported outcomes. RESULTS: Of 196 references identified, 10 studies totaling 929 patients met the inclusion criteria. Reported mean anchor density varied from 1.06 to 2.0 implants per level fused. Mean percent coronal curve correction varied from 64% to 70%. Two studies (463 patients) analyzed hook, hybrid (combined hooks and screws), and screw constructs as a single cohort. Both found increased correction with high-density constructs (p = .01, p < .001), perhaps as a result of the hooks and hybrid constructs. Eight retrospective studies and 1 prospective randomized, controlled trial had predominantly screw constructs (466 patients). Increased anchor density was not associated with improved curve correction. The studies evaluating screw density are significantly underpowered to detect a difference in curve correction. CONCLUSIONS: Wide heterogeneity in anchor density exists in the surgical treatment of AIS. Reports evaluating the effects of increased anchor density are mostly retrospective and significantly underpowered to detect a difference in curve correction and patient outcomes. At this time, there is insufficient evidence to show that anchor density affects clinical outcomes in AIS.

Adult Degenerative Scoliosis Surgical Outcomes: A Systematic Review and Meta-analysis.

INTRODUCTION: There is increasing awareness of adult degenerative or de novo scoliosis, and its surgical treatment when indicated can be challenging and resource intense. Surgical randomized controlled trials are rare, and observational studies pose limitations because of the heterogeneity of surgical practices, techniques, and patient populations. Pooled analysis of current literature may identify effective treatment strategies and guide future efforts at prospective clinical research. This study aimed to synthesize existing data on the outcomes of surgical intervention for adult degenerative scoliosis. METHODS: PubMed, Medline, Cochrane, and Web of Science databases were searched using key words and were limited to the English language. Spine surgeons reviewed abstracts and evaluated whether they contained surgically treated cohorts of adults (more than 18 years of age) with degenerative scoliosis. Full-text articles were reviewed in detail and data were abstracted. All meta-analyses were conducted using random effects models and heterogeneity was estimated with I2. Random-effects meta-regression models were used to investigate the association of treatment effects with baseline levels of each outcome. RESULTS: Of 482 articles, 24 (n = 805) met inclusion criteria Available outcomes included Cobb angle correction, coronal and sagittal balance, visual analog scale for pain (VAS), and Oswestry Disability Index. Despite significant heterogeneity among studies, random-effects meta-analysis showed significant improvements in Cobb angle (-11.1°; 95% confidence interval [CI], -13.86° to -8.40°), coronal balance (7.674 mm; 95% CI, -10.5 to -4.9), VAS (-3.24; 95% CI, -4.5 to -1.98), and Oswestry Disability Index (-27.18%; 95% CI, -34.22 to -20.15) postoperative treatment (p < .001). Meta-regression models showed that preoperative values for Cobb angle, coronal balance, and VAS were significantly associated with surgical treatment effect (p < .05). Changes in sagittal balance did not reach statistical significance although only 6 articles were included. CONCLUSIONS: Exhaustive literature review yielded 24 studies reporting preoperative and postoperative data regarding the surgical treatment of adult degenerative scoliosis. No randomized clinical trials (RCTs) were identified. Despite heterogeneity, a limited meta-analysis showed significant improvement in Cobb angle, coronal balance, and VAS after surgical treatment of adult degenerative scoliosis.

Pediatric pedicle screw placement using intraoperative computed tomography and 3-dimensional image-guided navigation.

STUDY DESIGN: A retrospective cohort study reporting the use of intraoperative computed tomography (CT) and image-guided navigation system for the placement of pedicle screws in pediatric compared with adult patients. OBJECTIVE: To evaluate the accuracy of open pedicle screw placement in pediatric patients using intraoperative CT and 3-dimensional (3D) image-guided navigation. SUMMARY OF BACKGROUND DATA: Pedicle screws are widely used in children for the correction of spinal deformity. Navigation systems and intraoperative CT are now available as an adjunct to fluoroscopy and anatomic techniques for placing pedicle screws and verifying screw position. METHODS: From 2007 to 2010, 984 pedicle screws were placed in a consecutive series cohort of 50 pediatric patients for spinal deformity correction with the use of intraoperative CT (O-arm, Medtronic, Inc, Louisville, CO) and a computerized navigation system (Stealth, Medtronic, Inc, Louisville, CO). The primary outcome measure for this study is redirection or removal of screw on the basis of the intraoperative CT imaging. During the study period, 1511 screws were placed in adult patients using the same image guidance system. RESULTS: A total of 984 pedicle screws were implanted using real-time navigation, with a mean of 20 screws per patient (range: 2-34). On the basis of intraoperative CT, 35 screws (3.6%) were revised (27 redirected and 8 removed), representing a 96.4% accuracy rate. No patients returned to the operating room because of screw malposition.Of the 1511 screws placed in adult patients, 28 (1.8%) were revised intraoperatively for malposition on CT imaging, for an overall 98.2% accuracy rate. Screw revision thus was more common in the pediatric population (P = 0.008). However, the pediatric screw accuracy rate is significantly higher than the findings from a recent meta-analysis of predominantly nonnavigated screws in children, reporting a 94.9% accuracy rate (P = 0.03). CONCLUSION: We report 96.4% accuracy in pediatric pedicle screw placement using intraoperative CT and a 3D navigation system. This is similar to other reports and has better accuracy than a recent meta-analysis of nonnavigated screws in children.

An analysis of decision making and treatment in thoracolumbar metastases.

STUDY DESIGN: Systematic review of literature. OBJECTIVE: To determine whether surgical approach and technique to be used in thoracolumbar metastases is influenced by anatomic region of the spine. SUMMARY OF BACKGROUND DATA: There is a significant debate about the best surgical approach for the treatment of thoracolumbar metastasis. METHODS: Two research questions below were determined through a consensus among a panel of spine experts. A systematic review of literature was conducted using Pubmed. The search terms included "spin*" and "metasta*." This was to include the terms, "metastatic," "metastasis," "metastases," "spinal," and "spine." 1. In the T2 to T5 region, what is the impact of different surgical approaches (anterior, posterior, combined anteroposterior [AP]) on local recurrence, adverse events, pain alleviation, and neurologic recovery? 2. Within the thoracolumbar spine (T6-T10; T11-L2; and L3-L5) what is the impact of different surgical approaches on outcomes as per question one. The results of the systematic review were discussed with spine oncology experts through a modified Delphi technique to arrive at treatment recommendations. RESULTS: From the search terms used 5176 abstracts were found. Based on the review of these abstracts, 161 were deemed acceptable. These abstracts were reviewed according to an inclusion and exclusion criteria, leaving 60 articles. These 60 articles were reviewed in detail leaving 32 articles for inclusion. There was no level I study. There was 1 level II study, 5 level III studies, and 26 level IV studies. Most of these studies selected their approach by tumor topography. The quality of evidence was very low. CONCLUSION: There is very low quality evidence to support the superiority of one approach over another. There is a strong recommendation for posterior or posterior-lateral approach from T2 through T5. For the T6-L5 regions of the spine we recommend either anterior, posterior, or combined anterior and posterior surgery depending on the clinical presentation, surgeon and patient preference.