Early Complications After Posterior Spinal Fusion in Patients With Rett Syndrome.

BACKGROUND: Neuromuscular scoliosis in Rett syndrome (RS) is common, progressive, and often requires posterior spinal fusion (PSF). While PSF is associated with improved overall outcomes, there is a paucity of information describing complications. We aimed to report the postoperative complications, readmissions, and reoperations for patients with RS undergoing PSF. METHODS: Female pediatric patients with RS treated by PSF with segmental instrumentation, with or without concurrent pelvis fixation, during January 2012 to August 2022 were included. Preoperative patient characteristics, intraoperative data (estimated blood loss, cell saver, packed red blood cells transfused), postoperative complications according to the Modified Clavien-Dindo-Sink classification within 90 days, unplanned readmissions within 30 days, and unplanned reoperations within 90 days were recorded. RESULTS: A total of 25 females were included. The mean (SD) age at surgery was 12.9 (1.8) years and the mean follow-up of 38.6 (24.9) months. The mean preoperative major coronal curve was 79 degrees (23 degrees) which decreased to 32 degrees (15 degrees) by the last follow-up ( P <0.001). The median estimated blood loss was 600 mL and length of stay was 7 days. There were 81 total postoperative complications (3.2 complications/patient). Eight (32%) had grade IVa complications (disseminated intravascular coagulopathy, hypotensive shock, respiratory failure, chronic urosepsis). Five (20%) patients experienced seizures, 48% had pulmonary complications, and 56% had gastrointestinal complications. There were 3 readmissions (12%) within 30 days for pneumonia and 2 (8%) reoperations (an incision and drainage and C2-T2 fusion for significant kyphosis) within 90 days. One patient also had their fusion extended to the pelvis 1 year later. There were more nonambulatory patients in the group fused to the pelvis, but otherwise no differences between those fused and unfused to the pelvis. CONCLUSIONS: This is the largest review of early postoperative complications for patients with RS who underwent PSF. PSF effectively reduced the major coronal curve, but surgeons and families should be aware of a high postoperative seizure and respiratory complication rate, as well as 8% having reoperations within 90 days and 12% being readmitted within 30 days. LEVEL OF EVIDENCE: Level IV-therapeutic study.

Obesity and perioperative adverse events in patients undergoing complex revision surgery for the thoracolumbar spine.

BACKGROUND: There are no previous studies that evaluate the effect of obesity on patients undergoing complex revision thoracolumbar spine surgery. The primary objective was to determine the relationship between obesity and perioperative adverse events (AEs) with patients undergoing complex revision thoracolumbar spine surgery while controlling for psoas muscle index (PMI) as a confounding variable. The secondary objective was to determine the relationship between obesity and 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, and post-operative length of stay (LOS). METHODS: Between May 2016 and February 2020, a retrospective analysis of individuals undergoing complex revision surgery of the thoracolumbar spine was performed at a single institution. Obesity was defined as BMI ≥ 30.0 kg/m2. PMI < 500 mm2/m2 for males and < 412 mm2/m2 for females were used to define low muscle mass. A Spine Surgical Invasiveness Index (SSII) > 10 was used to define complex revision surgery. A multivariable logistic regression model was used to ascertain the effects of low muscle mass, obesity, age, and gender on the likelihood of the occurrence of any AE. RESULTS: A total of 114 consecutive patients were included in the study. Fifty-four patients were in the obese cohort and 60 patients in the non-obese cohort. There was not a significant difference in perioperative outcomes of both the obese and non-obese patients. There were 22 obese patients (40.7%) and 33 non-obese patients (55.0%) that experienced any AE (p = 0.130). Multivariable analysis demonstrated that individuals with low muscle mass had a significantly higher likelihood for an AE than individuals with normal or high muscle mass (OR: 7.53, 95% CI: 3.05-18.60). Obesity did not have a significant effect in predicting AEs. CONCLUSIONS: Obesity is not associated with perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, or post-operative length of stay (LOS) among patients undergoing complex revision thoracolumbar spine surgery. LEVEL OF EVIDENCE: III.

S2 alar-iliac screw versus traditional iliac screw for spinopelvic fixation: a systematic review of comparative biomechanical studies.

PURPOSE: To review and compare biomechanical properties between S2 alar-iliac (S2AI) screws and traditional iliac screws for spinopelvic fixation. METHODS: A systematic review was performed according to PRISMA guidelines. All clinical, cadaveric, and finite-element model (FEM) studies that compared the biomechanical properties between S2AI screws and traditional iliac screws were included. Study methodological quality for cadaveric studies were analyzed using the Quality Appraisal for Cadaveric Studies (QUACS) scale. RESULTS: Eight studies (4 cadaveric, 4 FEM) analyzing 58 S2AI screws and 48 traditional iliac screws were included. According to QUACS, the overall methodological quality was "moderate to good" for all four cadaveric studies. All four cadaveric studies found no difference in biomechanical stiffness, screw toggle, rod strain, and/or load-to-failure between the S2AI screws and traditional iliac screws for spinopelvic fixation. All four FEM studies found that S2AI screws were associated with lower implant stresses compared to traditional iliac screws. CONCLUSIONS: There is moderate biomechanical evidence to suggest that there is no significant difference in stability and stiffness between S2AI screws and traditional iliac screws for spinopelvic fixation. However, there is some evidence to support that the placement of S2AI screws may have lower implant stresses on the overall lumbosacral instrumentation compared to traditional iliac screws.

Scoliosis Following Chest Wall Resection for Tumor With and Without Prophylactic Fixation: Case Series.

Posterior chest wall resection is a complex surgical procedure that involves removing any anatomical structure that surrounds the lungs and pleura, such as the intercostals, ribs, and soft tissues. The etiology of scoliosis that develops after chest wall excision is likely both mechanical and paralytic in nature. We report seven cases of scoliosis following posterior chest wall resection. Our results suggest that the prophylactic treatment of scoliosis after chest wall resection decreases the risk of scoliosis.

Anterior versus posterior spinal fusion for Lenke type 5 adolescent idiopathic scoliosis: a systematic review and meta-analysis of comparative studies.

PURPOSE: To review and compare clinical and radiologic outcomes between anterior spinal fusion (ASF) and posterior spinal fusion (PSF) for the treatment of Lenke type 5 adolescent idiopathic scoliosis (AIS). METHODS: A systematic review was performed according to Preferred reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. All level I-III evidence studies investigating the clinical and radiologic outcomes of ASF and PSF for the treatment of Lenke type 5 AIS were included. RESULTS: Nine studies (285 ASF patients, 298 PSF patients) were included. ASF was associated with a significantly lower number of levels fused compared with PSF (p < 0.01) with similar immediate and long-term coronal deformity correction (p = 0.16; p = 0.12, respectively). PSF achieved a better correction of thoracic hypokyphosis in one study and lumbar hypolordosis in three studies. PSF was associated with a significant shorter length of stay (LOS) compared with ASF (p < 0.01). One long-term study demonstrated a significantly higher rate of proximal junctional kyphosis (PJK) with PSF compared with ASF. There were no significant differences in major complication or re-operation rates. CONCLUSION: For the treatment of Lenke type 5 AIS, there is moderate evidence to suggest that ASF requires a lower number of instrumented levels to achieve similar immediate and long-term coronal deformity correction compared with PSF. There is some evidence to suggest that PSF may achieve better thoracic and lumbar sagittal deformity correction compared with ASF. There is some evidence to suggest a higher incidence of PJK at long-term follow-up with PSF compared with ASF. ASF is associated with a longer post-operative LOS compared with PSF.

Sarcopenia predicts perioperative adverse events following complex revision surgery for the thoracolumbar spine.

BACKGROUND CONTEXT: Sarcopenia measured by psoas muscle index (PMI) has been shown to predict perioperative mortality and adverse events (AEs) after various surgical procedures. However, this relationship has not been studied in complex revision thoracolumbar spine surgery. PURPOSE: This study aimed to determine the relationship between sarcopenia and perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery. STUDY DESIGN: Retrospective cohort study PATIENT SAMPLE: A retrospective analysis was performed at a single institution between May 2016 and February 2020 of patients undergoing complex revision thoracolumbar spine surgery by three board certified fellowship-trained orthopaedic spine surgeons. OUTCOME MEASURES: Perioperative adverse events including postoperative anemia requiring transfusion, cardiac complication, sepsis, wound complication, delirium, intra-operative dural tear, acute kidney injury, pneumonia, urinary tract infection, urinary retention, epidural hematoma, and deep vein thrombosis. Secondary outcome measures were 30-day readmission rates, 30-day re-operation rates, in-hospital mortality rates, discharge disposition, and postoperative length of stay (LOS). METHODS: Sarcopenia was analyzed using PMI, calculated at the L3 vertebral body measured on preoperative magnetic resonance imaging (MRI) or computed tomography (CT) normalized to height2 (mm2/m2). Receiver operating characteristic (ROC) curve analysis and Youden index were used to determine gender-specific PMI cut-off values for predicting perioperative AEs. Sarcopenia was defined as PMI below the cut-off values. Complex revision surgery was defined as Spine Surgical Invasiveness Index >10. RESULTS: A total of 114 consecutive patients were included in the study. ROC curve analysis demonstrated PMI <500 mm2/m2 for males and <412 mm2/m2 for females as predictors for perioperative AEs. 49 patients were in the sarcopenia cohort and 65 patients in the nonsarcopenia cohort. The sarcopenia group had higher overall perioperative AEs (75.5% vs 27.7%, p<.001) and individual AEs including: postoperative anemia requiring transfusion, wound complication, delirium, acute kidney injury, pneumonia, urinary tract infection, and deep vein thrombosis. The sarcopenia group had higher 30-day reoperation rate (14.3% vs 3.1%, p=.037), 30-day readmission rate (16.3% vs 3.1%, p=.018), rate of discharge to a facility (83.7% vs 50.8%, p<.001), and longer length of stay (LOS) (7.3±4.2 days vs 5.6±3.5 days, p=.023). CONCLUSIONS: Sarcopenia measured by PMI is associated with higher perioperative AEs, 30-day readmission rates, 30-day reoperation rates, rate of discharge to a facility, and longer LOS among patients undergoing complex revision thoracolumbar spine surgery.

The Incidence of Vertebral Exostoses in Multiple Hereditary Exostoses and Recommendations for Spinal Screening.

BACKGROUND: Multiple hereditary exostoses (MHE) lead to the development of pedunculated or sessile osteocartilaginous lesions. Vertebral involvement occurs in MHE and encroaching intracanal exostoses can result in devastating consequences. Magnetic resonance imaging (MRI) of the entire spine has been used to screen for vertebral exostoses to detect high-risk patients. The primary purpose of this investigation is to determine the incidence of vertebral and encroaching intracanal exostoses in patients with MHE. A secondary purpose is to determine if pelvis and rib exostoses serve as "harbinger" lesions of vertebral involvement in MHE. METHODS: A retrospective chart review was performed on 39 patients (21 male and 18 female individuals) with MHE who underwent routine spinal screening with noncontrast entire spine MRI. The average age at screening was 12.3 years (range, 3 to 17 y). Screening was ordered consecutively on patients seen during the study period who were between ages 8 and 18 years or had complaints that could be related to encroaching intracanal exostoses. RESULTS: The incidence of vertebral exostoses in this cohort of 39 patients with MHE was 28% (11 total). An encroaching intracanal exostosis was seen in 3 patients (2 cervical, 1 thoracic). Nonencroaching vertebral exostoses were discovered in 8 patients. Sufficient pelvis and rib imaging to determine the presence of pelvis and rib exostoses was available in 8 of those with vertebral exostoses and 19 of those with no vertebral exostoses on screening MRI. In this cohort, the sensitivity and specificity of the presence of both pelvis and rib exostoses for determining the presence of spinal involvement in MHE are 88% and 5%, respectively. CONCLUSIONS: Based on the results of this cohort, vertebral exostoses are common in MHE, and screening MRI of the entire spine can be used to determine which patients need close observation. If a more selective screening protocol is utilized, an entire spine MRI could be obtained for patients who desire increased physical activity levels or for patients with both pelvis and rib exostoses. At a minimum, treating physicians should monitor patients with MHE closely for neurological symptoms and have a low threshold to obtain advanced spinal imaging. LEVEL OF EVIDENCE: Level III-diagnostic.

Clinical Effectiveness of S2-Alar Iliac Screws in Spinopelvic Fixation in Pediatric Neuromuscular Scoliosis: Systematic Literature Review.

STUDY DESIGN: Systematic literature review. OBJECTIVES: To comprehensively review the S2-alar iliac (S2-AI) screw technique for pelvic fixation in pediatric neuromuscular scoliosis. METHODS: Articles identified from the PubMed and EMBASE databases were reviewed for relevance and applicability, and the studies were summarized. RESULTS: Eight articles met the inclusion criteria. A total of 277 pediatric patients underwent spinopelvic fixation using S2-AI fixation for neuromuscular scoliosis; the mean follow-up was 3 years (range = 0.75-6 years). Six articles had level III evidence (5 retrospective cohort studies, 1 observational study), and 2 articles had level IV evidence (case series). Wound complications occurred in 34 (12.2%) patients. Instrumentation complications occurred in 36 patients (13.0%), including lucency around the screw (6.5%), screw fracture (3.6%), disengaging of the set/screw or rod from the tulip head (2.8%), and screw displacement (0.7%). Three patients (1.1%) required reoperation for instrumentation failures. The overall reoperation rate-including 3 hardware replacements and 3 cases of L5-S1 pseudarthrosis-was 2.1%. The mean Cobb angle correction was 51.4°, and the mean pelvic obliquity correction was 14.8°; deformity correction was maintained at 3- and 5-year follow-ups. There were 10 (3.6%) cases of implant prominence/implant-related pain, 1 case of sacroiliac joint pain (resolved with longer screw placement), and no major neurological or vascular complications secondary to S2-AI screw placement. CONCLUSIONS: This review suggests that the use of S2-AI screws in pediatric neuromuscular scoliosis is efficacious with a reasonable safety profile and provides a useful technique for pelvic fixation in children with scoliosis.

Impact of scoliosis surgery on pulmonary function in patients with muscular dystrophies and spinal muscular atrophy.

BACKGROUND: Scoliosis is a common complication of severe neuromuscular diseases. The aim of this study is to determine the impact of posterior spinal fusion on pulmonary function parameters in patients with severe neuromuscular disease at our medical center. METHODS: Retrospective chart review of all patients with severe neuromuscular disease who had posterior spinal fusion between 2012 and 2017 at Texas Children's Hospital. Patients with growing rods, brain injury or malformation, and/or spina bifida were excluded. Pulmonary function measures before and after spinal surgery were determined. RESULTS: A total of 20 eligible patients were identified, 7 with Duchenne muscular dystrophy, 6 with spinal muscular atrophy, 3 with merosin deficient muscular dystrophy, 2 with Charcot-Marie-Tooth, 1 with central core disease, and 1 with dystroglycanopathy. The mean change in vital capacity from pre- to postspine surgery was a loss of 0.63 L for the spinal muscular atrophy patients, a loss of 0.36 L for the Duchenne muscular dystrophy patients, and a gain of 0.23 L for the merosin deficient patients. The difference between spinal muscular atrophy and merosin deficient patients was statistically significant (P = .02) CONCLUSION: In this single-center retrospective study, we found that after spine surgery for scoliosis, all patients with spinal muscular atrophy and most patients with Duchenne muscular dystrophy lost vital capacity, while the patients with merosin deficient muscular dystrophy gained vital capacity. These differences were not associated with differences is respiratory strength, body mass index, or surgical outcomes.

Risk Factors for Development and Progression of Scoliosis After Pediatric Cardiothoracic Operations.

BACKGROUND: The purpose of this study was to determine the incidence and risk factors for the development and rate of progression of scoliosis and moderate/severe scoliosis in patients undergoing cardiothoracic operations (CTOs). METHODS: Included were patients aged younger than 12 years who underwent CTOs in 1995 to 2006 with a preoperative chest roentgenogram (CRG) and a CRG at least 8 years after CTOs. Scoliosis and moderate/severe scoliosis were defined as a Cobb angle of 10 degrees or more and an angle of 25 degrees or more or the need for surgical intervention, respectively. Risk factors were analyzed using nonparametric and parametric survival analyses. For patients that developed scoliosis, progression rate was analyzed using linear regression models for repeated measures using CRG at 6-month intervals. RESULTS: The study included 871 patients (380 girls [44%]). Median CRG follow-up was 11 years (interquartile range, 9 to 13 years). Overall 10-year incidence of scoliosis and moderate/severe scoliosis was 12% and 3%, respectively. Independent predictors for scoliosis included female sex (hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.2 to 2.5), syndrome (HR, 1.9; 95% CI, 1.3 to 2.8), and isolated developmental delay (HR, 2.4; 95% CI, 1.4 to 4.2). For development of moderate/severe scoliosis, independent risk factors included female sex (HR, 2.8; 95% CI, 1.4 to 5.8), syndrome (HR, 3; 95% CI, 1.5 to 6.1), isolated developmental delay (HR, 3.1; 95% CI, 1 to 9.2]), and prematurity for neonates/infants (HR, 2.3; 95% CI, 1 to 5.2). Rate of angle progression was 0.17 times the current angle per year. Age, syndrome, and developmental delay were risk factors for angle progression. CONCLUSIONS: Patients that undergo pediatric CTO, regardless of the operative approach, are at increased risk for development of scoliosis and moderate/severe scoliosis. Long-term follow-up of these patients is warranted, in particular for girls and patients with genetic syndromes or developmental delay.

Neuromuscular scoliosis complication rates from 2004 to 2015: a report from the Scoliosis Research Society Morbidity and Mortality database.

OBJECTIVE Postoperative complications are one of the most significant concerns in surgeries of the spine, especially in higher-risk cases such as neuromuscular scoliosis. Neuromuscular scoliosis is a classification of multiple diseases affecting the neuromotor system or musculature of patients leading to severe degrees of spinal deformation, disability, and comorbidity, all likely contributing to higher rates of postoperative complications. The objective of this study was to evaluate deformity correction of patients with neuromuscular scoliosis over a 12-year period (2004-2015) by looking at changes in postsurgical complications and management. METHODS The authors queried the Scoliosis Research Society (SRS) Morbidity and Mortality (M&M) database for neuromuscular scoliosis cases from 2004 to 2015. The SRS M&M database is an international database with thousands of self-reported cases by fellowship-trained surgeons. The database has previously been validated, but reorganization in 2008 created less-robust data sets from 2008 to 2011. Consequently, the majority of analysis in this report was performed using cohorts that bookend the 12-year period (2004-2007 and 2012-2015). Of the 312 individual fields recorded per patient, demographic analysis was completed for age, sex, diagnosis, and preoperative curvature. Analysis of complications included infection, bleeding, mortality, respiratory, neurological deficit, and management practices. RESULTS From 2004 to 2015, a total of 29,019 cases of neuromuscular scoliosis were reported with 1385 complications, equating to a 6.3% complication rate when excluding the less-robust data from 2008 to 2011. This study shows a 3.5-fold decrease in overall complication rates from 2004 to 2015. A closer look at complications shows a significant decrease in wound infections (superficial and deep), respiratory complications, and implant-associated complications. The overall complication rate decreased by approximately 10% from 2004-2007 to 2012-2015. CONCLUSIONS This study demonstrates a substantial decrease in complication rates from 2004 to 2015 for patients with neuromuscular scoliosis undergoing spine surgery. Decreases in specific complications, such as surgical site infection, allow us to gauge our progress while observing how trends in management affect outcomes. Further study is needed to validate this report, but these results are encouraging, helping to reinforce efforts toward continual improvement in patient care.

Complications in spinal fusion for adolescent idiopathic scoliosis in the new millennium. A report of the Scoliosis Research Society Morbidity and Mortality Committee.

STUDY DESIGN: The Morbidity and Mortality database of the Scoliosis Research Society (SRS) was queried as to the incidence and type of complications as reported by its members for the treatment of adolescent idiopathic scoliosis (AIS) with spinal fusion and instrumentation procedures regarding surgical approach (anterior, posterior, or combined anterior-posterior) during a recent 3-year period. OBJECTIVE: To evaluate the incidence of surgeon-reported complications in a large series of spinal fusions with instrumentation for a single spinal deformity diagnosis and age group regarding surgical approach. SUMMARY OF BACKGROUND DATA: The SRS has been collecting morbidity and mortality data from its members since its formation in 1965 with the intent of using these data to assess the complications and adverse outcomes (death and/or spinal cord injury) of surgical treatment for spinal deformity. Surgical approaches to the management of treatment of AIS have a measurable impact on efficacy of correction, levels fused, and operative morbidity. However, there is a lack of consensus on the choice of surgical approach for the treatment of spinal deformity. METHODS: Of the 58,197 surgical cases submitted by members of the SRS in the years 2001, 2002, and 2003, 10.9% were identified as having had anterior, posterior, or combined spinal fusion with instrumentation for the diagnosis of AIS, and comprised the study cohort. All reported complications were tabulated and totaled for each of the 3 types of procedures, and statistical analysis was conducted. RESULTS: Complications were reported in 5.7% of the 6334 patients in this series. Of the 1164 patients who underwent anterior fusion and instrumentation, 5.2% had complications, of the 4369 who underwent posterior instrumentation and fusion, 5.1% had complications, and of the 801 who underwent combined instrumentation and fusion, 10.2% had complications. There were 2 patients (0.03%) who died of their complications. There was no statistical difference in overall complication rates between anterior and posterior procedures. However, the difference in complication rates between anterior or posterior procedures compared to combined procedures was highly significant (P < 0.0001). The differences in neurologic complication rates between combined and anterior procedures, as well as combined and posterior procedures were also highly statistically significant (P < 0.0001), but not between anterior and posterior procedures. CONCLUSIONS: This study shows that complication rates are similar for anterior versus posterior approaches to AIS deformity correction. Combined anterior and posterior instrumentation and fusion has double the complication rate of either anterior or posterior instrumentation and fusion alone. Combined anterior and posterior instrumentation and fusion also has a significantly higher rate of neurologic complications than anterior or posterior instrumentation and fusion alone.

Sagittal plane analysis of adolescent idiopathic scoliosis: the effect of anterior versus posterior instrumentation.

STUDY DESIGN: Radiographic analysis of anterior and posterior instrumentation for adolescent idiopathic scoliosis. OBJECTIVES: To compare effects of anterior versus posterior instrumentation on sagittal plane parameters. SUMMARY OF BACKGROUND DATA: The sagittal plane is critical to the long-term success of scoliosis surgery, but few studies have compared the effect of anterior versus posterior instrumentation. METHODS: Standing, full spine lateral radiographs of 110 consecutive patients (mean age 14 years) who had surgery for adolescent idiopathic scoliosis between 1996 and 1998 at one institution with a minimum 24-month (mean 32 months) follow-up were evaluated. Fifty patients were instrumented anteriorly with single screw-rod constructs. Sixty patients were instrumented posteriorly with segmental implants (5.5 mm; hooks, wires, and/or pedicle screws). RESULTS: At the final follow-up, the proximal junctional measurement (measured between the proximal instrumented vertebra and the segment two levels cephalad) increased most with posterior instrumentation (+7 degrees increase for posterior thoracic +1 degrees increase for anterior thoracic instrumentation, P= 0.02; +9 degrees increase for posterior thoracic and lumbar instrumentation vs. +4 degrees for anterior thoracolumbar instrumentation, P= 0.03). Thoracic kyphosis (T5-T12) increased significantly with anterior versus posterior thoracic instrumentation (+4 degrees vs. -2 degrees change, P= 0.04). Lumbar lordosis (T12-S1) was enhanced with either anterior or posterior instrumentation. No significant changes in distal junctional measurement (measured between the distal instrumented vertebra and the segment two levels caudal) were noted. The C7 sagittal plumbline remained negative in all groups at the final follow-up. CONCLUSION: Anterior and posterior instrumentation had differential effects on the sagittal plane in patients with adolescent idiopathic scoliosis. However, the overall magnitude of the differences was small. Properly performed, both approaches can result in acceptable sagittal profiles.

Dowel fibular strut grafts for high-grade dysplastic isthmic spondylolisthesis.

STUDY DESIGN: This is a clinical study that examines the results of partial reduction and fibular dowel graft placement for high-grade isthmic spondylolisthesis. OBJECTIVES: To demonstrate the efficacy of partial reduction and fibular dowel graft placement in the treatment of high-grade isthmic spondylolisthesis. SUMMARY OF BACKGROUND DATA: Previous literature has demonstrated difficulty in treating high-grade isthmic spondylolisthesis both with high rates of pseudarthrosis as well as neurologic complications if a complete reduction is attempted. There are no published data examining partial reduction with dowel graft placement. METHODS: Seventeen consecutive patients (mean age 20.3 years) with high-grade isthmic spondylolisthesis who were treated with posterior fusion and fibular strut grafts were studied (mean follow-up 4.6 years). Radiographs were reviewed at preoperative, immediate (within 3 months) postoperative, and ultimate (>2 years) follow-up. Parameters measured included lumbar lordosis, slip angle, Meyerding-Newman scores, and pelvic incidence. The anterior and posterior fusions were graded on a I-IV scale, and the implants (if used) were examined for failure. Clinical outcomes were measured with Oswestry and Scoliosis Research Society outcomes tools. RESULTS: There were 17 patients treated: 10 primary and 7 revision patients. All patients had posterior fusion with fibular dowel grafts (11 allograft, 6 autograft). Meyerding grade improved 1.3 grades and slip angle improved 14 degrees with no loss of correction at ultimate follow-up. Sixteen of 17 patients had solid fusions on ultimate follow-up. Clinical evaluation with Scoliosis Research Society and Oswestry tools showed high patient function and satisfaction. Complications included one case of a broken strut in a revision patient; this was then revised to an instrumented circumferential fusion. There were no cases of deep or superficial infection. There were no neurologic deficits at ultimate follow-up. CONCLUSION: Fibular strut grafting is a useful surgical adjunct in high-grade spondylolisthesis that is partially reduced. Clinical and radiographic outcomes were satisfactory. Our experience shows that there is no significant difference between allograft and autograft. All struts healed and remodeled by the ultimate follow-up, and there was only one instance of fibula fracture.

Correlation of pelvic incidence with low- and high-grade isthmic spondylolisthesis.

PURPOSE: The development of isthmic spondylolisthesis is influenced by forces across the lumbosacral region of the spine. Pelvic incidence is a radiographic parameter that has been shown to be an independent parameter that influences both sagittal spinal balance and pelvic orientation. Our hypothesis then is that there is a positive correlation between pelvic incidence and spondylolisthesis. STUDY DESIGN: A radiographic analysis of cases with spondylolisthesis. OBJECTIVES: To try to assess the correlation between pelvic incidence in both low-grade and high-grade spondylolisthesis in both a pediatric and an adult population. SUMMARY OF BACKGROUND DATA: The concept of pelvic incidence has been introduced into the literature. Its exact association with spondylolisthesis has not yet been clarified. METHODS: Forty patients with spondylolisthesis were identified and divided into two groups: low-grade (Meyerding I-II) and high-grade (Meyerding III and higher). Radiographic parameters measured included lumbar sagittal alignment (T12-S1), sacral inclination, slip angle, and pelvic incidence. The spondylolisthesis was classified according to the Meyerding-Newman classifications and the slip angle. Radiographic measurements were also done in two control groups; there were 20 pediatric and 20 adult controls (mean age 11.8 years and 60.0 years, respectively). Unpaired t test analysis and Pearson correlation analysis were then done. RESULTS: Mean pelvic incidence was 47.4 degrees in the pediatric control group, 57 degrees in the adult control group, 68.5 degrees in the low-grade isthmic spondylolisthesis group, and 79.0 degrees in the high-grade isthmic spondylolisthesis group. Pelvic incidence was found to be significantly higher in the high- and low-grade spondylolisthesis groups compared with both control groups (P = 0.0001). Pelvic incidence was significantly higher in the high-grade isthmic spondylolisthesis group than in the low-grade isthmic spondylolisthesis group (P = 0.007). A significant correlation existed between pelvic incidence and Meyerding-Newman scores (P = 0.03). CONCLUSIONS: Pelvic incidence was significantly higher in patients with low- and high-grade isthmic spondylolisthesis as compared with controls and had significant correlation with the Meyerding-Newman grades (P = 0.03).

Can triggered electromyograph thresholds predict safe thoracic pedicle screw placement?

STUDY DESIGN: A prospective clinical study of thoracic pedicle screws monitored with triggered electromyographic testing. OBJECTIVE: To evaluate the sensitivity of recording rectus abdominis triggered electromyographs to assess thoracic screw placement. SUMMARY OF BACKGROUND DATA: Triggered electromyographic testing from lower extremity myotomes has identified medially placed lumbar pedicle screws. Higher thresholds indicate intraosseous placement because of increased resistance to current flow. Lower thresholds correspond to compromised pedicles with potential for nerve impingement. No clinical study has correlated an identical technique with rectus muscle recordings, which are innervated from T6 to T12. METHODS: A total of 677 thoracic screws were placed in 92 consecutive patients. Screws placed from T6 and T12 were evaluated using an ascending method of stimulation until a compound muscle action potential was obtained from the rectus abdominis. Threshold values were compared both in absolute terms and also in relation to other intrapatient values. RESULTS: Screws were separated into three groups: Group A (n = 650 screws) had thresholds >6.0 mA and intraosseus placement. Group B (n = 21) had thresholds <6.0 mA but an intact medial pedicle border on reexamination and radiographic confirmation. Group C (n = 6) had thresholds <6.0 mA and medial wall perforations confirmed by tactile and/or visual inspection. Thus, 3.9% (27 of 677) of all screws had thresholds <6.0 mA. Only 22% (6 of 27) had medial perforation. Group B screws averaged a 54% decrease from the mean as compared with a 69% decrease for Group C screws (P = 0.0160). There were no postoperative neurologic deficits or radicular chest wall complaints. CONCLUSION: To assess thoracic pedicle screw placement, triggered electromyographic thresholds <6.0 mA, coupled with values 60-65% decreased from the mean of all other thresholds in a given patient, should alert the surgeon to suspect a medial pedicle wall breach.

Correction of thoracic adolescent idiopathic scoliosis with segmental hooks, rods, and Wisconsin wires posteriorly: it's bad and obsolete, correct?

STUDY DESIGN: Forty-four consecutive thoracic idiopathic adolescent curves surgically treated between 1995 and 1999 at one institution were analyzed. All were thoracic curves; there were no lumbar curves, double major curves, or triple major curves. OBJECTIVES: To study the clinical and radiographic results for these 44 patients. SUMMARY OF BACKGROUND DATA: There is currently ongoing discussion regarding the "best treatment" for right thoracic idiopathic scoliosis. METHODS: Patients were administered preoperative and postoperative Scoliosis Research Society questionnaires. Radiographs were studied for coronal correction, sagittal correction, junctional deformities two segments above/two segments below, fusion status, loss of correction status, complications, and imbalance of curves above and below. Radiographic analysis was by two independent observers. All patients were treated with bilateral 5.5-mm CD Horizon (M-10) instrumentation. Corrective forces were translational and in situ contouring. An average of 10 hooks and 4 Wisconsin wires were used for an average of 14 fixation points per 11 segments. Follow-up was minimum 2 years to maximum 5 years, with an average of 3-year, 10-month follow-up. RESULTS: All were out of bed on postoperative day 1; none was braced after surgery. The average preoperative thoracic curve was 56 degrees; the average ultimate postoperative curve was 31 degrees (P = 0.0001). In the sagittal plane T5-T12 averaged 22 degrees preoperation and 20 degrees postoperation. For the complete study group (n = 44), the Cobb measurement (P = 0.001) and apical vertebral translation of the lumbar curve (P = 0.001) below improved. For the false double major curve (n = 11) patterns, the unfused lumbar curve averaged preoperation 46 degrees and postoperation 27 degrees (P = 0.0001). There were no neurologic deficits, no wound infections, and no respiratory complications. In regards to the Scoliosis Research Society questionnaires, significant (P < 0.05) changes preoperative to ultimate postoperative were found for questions 3, 5, 11, and 14. CONCLUSION: "Satisfactory" results were obtained in 44 patients treated with this technique. The complication rate was low and the fusion rate was high. Posterior treatment as described above produces reasonable and dependable results.