Faculty Bibliography

BACKGROUND CONTEXT: Adjacent segment degeneration (ASD) has been described after anterior cervical fusion surgeries though ASD is not always clinically relevant. Hilibrand et al described a grading system for ASD after anterior cervical fusion. We expand the ASD definition with an analysis of radiographic adjacent segment pathology (RASP) by also assessing the progression of kyphotic alignment, and spondylolisthesis at adjacent segments in patients following cervical laminoplasty (LP) and posterior cervical decompression and fusion (CDF). PURPOSE: To assess radiographic adjacent segment pathology by analyzing adjacent segment degeneration, and the progression of kyphotic alignment and spondylolisthesis at segments adjacent to operated levels for LP and CDF surgery. STUDY DESIGN/SETTING: Retrospective analysis of cervical radiographs in patients undergoing prior LP and CDF surgery. PATIENT SAMPLE: 64 patients undergoing prior LP and CDF surgery. OUTCOME MEASURES: NDI and mJOA. METHODS: Preoperative and postoperative radiographs were analyzed for ASD, progression of adjacent level kyphosis and spondylolisthesis at proximal, distal or any other segments. The RASP was determined by combining proximal and distal ASD, and the adjacent level kyphosis and spondylolisthesis into one spectrum of disease. The presence and rate of development of adjacent segment pathology was compared for LP and CDF. HRQOLs included NDI and mJOA. RESULTS: 64 patients were included (24 LP and 40 CDF) with mean age 59.9 years (46.9% female) and 30.2 months mean follow-up. Spondylolisthesis at the adjacent segment was more prevalent in CDF (29.2% vs 4.5%). Both LP and CDF demonstrated a similar rate of RASP (LP 40.9%, CDF 44%). NDI correlated with proximal adjacent level degeneration (r = 0.34, p = 0.024) and kyphosis (r = 0.36 p = 0.017). CONCLUSIONS: Both cervical laminoplasty and posterior cervical decompression and fusion are associated with adjacent level degeneration. However, there is a higher rate of adjacent segment spondylolisthesis after CDF. Motion preservation procedures may have less of a role in preventing adjacent level degeneration than previously thought. Adjacent segment degeneration correlated with NDI disability in these patients

BACKGROUND CONTEXT: Surgical management for the treatment of cervical spondylotic myelopathy (CSM) has been extensively documented and supported in recent literature. However, less is known regarding the risk associated with surgical treatment for CSM and factors influencing the development of postoperative surgical complications, which commonly range from 5%-10%. Similarly, the link between nonoperative modalities and associated factors on patient outcomes remains unclear. PURPOSE: This study aimed to investigate risk factors and impact on health related quality of life (HRQL) scores from baseline to 2 years postoperative among CSM surgical patients. STUDY DESIGN/SETTING: Retrospective review of a prospectively collected multicenter database. PATIENT SAMPLE: 203 surgical CSM patients were identified. OUTCOME MEASURES: Primary Measures: Baseline patient demographics, comorbidities, clinical information, nonoperative treatment modalities, surgical procedures and complication rates. Secondary Measures: HRQL data at two years postoperative, including SF-36 Physical (PCS) and Mental (MCS) Component Scores, and Neck Disability Index (NDI) scores. METHODS: A retrospective review performed on a prospectively collected database of CSM patients. Baseline patient demographics, comorbidities, clinical information, nonoperative treatment modalities, surgical procedures, and complication rates were collected. Health-related quality of life (HRQOL) outcomes assessed by SF-36 PCS, SF-36 MCS and NDI at baseline and two years postoperatively. Statistical analyses included paired sample t-tests and multivariate logistic regression controlling for age, gender, BMI. RESULTS: 203 CSM patients receiving surgical treatment were identified (43% female). The average age was 57.7 years and average BMI was 29.6 kg/m2. Prior to surgical intervention, patients underwent numerous forms of nonoperative treatment modalities: NSAIDs (34%), analgesics (32%) and physical therapy (26%) displayed the highest prevalence among the total cohort. The total complication rate was 7.4%. Notable complications included CSF leak (2.5%), other (unspecified) complications (2.5%), postoperative radiculopathy (1.0%) and excessive bleeding (1.0%). Only a previous history of cervical spine surgery was identified as the only significant positive risk factor for developing a complication (OR: 9.22, p=0.034). The average HRQL patient scores significantly improved for SF-36 PCS, SF- 36 MCS and NDI, from baseline to two years postoperatively (p<0.001). CONCLUSIONS: The total complication rate was 7.4% for CSM surgical patients. Baseline clinical information, comorbidities, use of nonoperative treatment modalities and surgical procedures were not significantly associated with increased risk of complication development. However, previous cervical spine surgeries increased the risk of complications nine-fold. Surgical patients also significantly improved in SF-36 PCS, MCS and NDI scores two years after surgery

BACKGROUND: HGS is a severe deformity most commonly affecting L5-S1 vertebral segment. Treatment available for HGS includes a range of different surgical options: full or partial reduction of translation and/or abnormal alignment and in situ fusion with or without decompression. Various instrumented or non-instrumented constructs are available, and surgical approach varies from anterior/posterior to combined depending on surgeon preference and experience. The aim of this systematic review was to review the literature on lumbosacral high-grade spondylolisthesis (HGS), identify patients at risk for progression to higher-grade slip and evaluate various surgical strategies to report on complications and radiographic and clinical outcomes. METHODS: Systematic search of PubMed, Cochrane and Google Scholar for papers relevant to HGS was performed. 19 articles were included after title, abstract, and full-text review and grouped to analyze baseline radiographic parameters and the effect of surgical approach, instrumentation, reduction and decompression on patient radiographic and clinical outcomes. RESULTS: There is a lack of high-quality studies pertaining to surgical treatment for HGS, and a majority of included papers were Level III or IV based on the JBJS Levels of Evidence Criteria. CONCLUSIONS: Surgical treatment for HGS can vary depending on patient age. There is strong evidence of an association between increased pelvic incidence (PI) and presence of HGS and moderately strong evidence that patients with unbalanced pelvis can benefit from correction of lumbopelvic parameters with partial reduction. Surgeons need to weigh the benefits of fixing the deformity with the risks of potential complications, assessing patient satisfaction as well as their understanding of the possible complications. However, further research is necessary to make more definitive conclusions on surgical treatment guidelines for HGS. LEVEL OF EVIDENCE: II.

OBJECT Lenke 1C curves are challenging to manage surgically due to the structural thoracic deformity and nonstructural lumbar curve. Selective thoracic fusion (STF) is considered the standard of care because it preserves motion of the lumbar segment, yet nonselective STF (NSTF) remains prevalent. This study aims to identify baseline patient characteristics that drive treatment and to compare postoperative outcomes for both procedures. METHODS Studies that compared baseline and postoperative demographic data, health-related quality of life (HRQL) questionnaires, and radiographic parameters of patients with Lenke 1C curves undergoing STF or NSTF were identified for meta-analysis. The effect measure is expressed as a mean difference (MD) with 95% CI. A positive MD signifies a greater STF value, or a mean increase within the group. RESULTS One prospective and 6 retrospective case-control studies with sample size of 488 patients (344 STF and 144 NSTF) were identified. Baseline age, sex, and HRQLs were equivalent, except for better scores in the STF group for the Scoliosis Appearance Questionnaire (SAQ): Unrelated to Deformity item (3.47 vs 3.88, p = 0.01) and the Spine Research Society questionnaire, Item 22: Pain (4.13 vs 3.92, p = 0.04). Radiographic findings were significantly worse in NSTF, as measured by the thoracolumbar/lumbar (TL/L) Cobb angle (MD: -4.29 degrees , p < 0.01) and TL/L apical vertebral translation (AVT) (MD: -6.08, p < 0.01). Radiographic findings significantly improved in STF, as measured in the main thoracic (MT) Cobb angle (MD: -27.78 degrees , p < 0.01), TL/L Cobb angle (MD: -16.24 degrees , p < 0.01), MT:TL/L Cobb ratio (MD: -0.21, p < 0.01), coronal balance (MD: 0.47, p = 0.02), and thoracic kyphosis (MD: 7.87 degrees , p < 0.01); and in NSTF in proximal thoracic (PT) Cobb angle (24 degrees vs 14.1 degrees , p < 0.01), MT Cobb angle (53.5 degrees vs 20.5 degrees , p < 0.01), and TL/L Cobb angle (41.6 degrees vs 16.6 degrees , p < 0.01). Postoperative TL/L Cobb angle (23.1 degrees vs 16.6 degrees , p < 0.01) was significantly higher in STF; but PT Cobb angle, MT Cobb angle, and MT:TL/L Cobb ratio are equivalent. CONCLUSIONS Patients with larger lumbar compensatory curves displaying a larger degree of coronal translation, as measured by the TL/L AVT, are more likely to undergo an NSTF. Contrary to established guidelines, larger MT curve magnitudes and MT:TL/L Cobb angle ratios have not been found to influence the decision to pursue a selective thoracic fusion. Although overall both STF and NSTF groups are found to have effective postoperative coronal balance, the STF group has only modest improvements in the lumbar curve position as determined by a relatively unchanged TL/L AVT. Furthermore, surgeons may prefer NSTF in patients who may have a worse overall perception of their spinal deformity as measured by HRQL measures of pain and desire for appearance change.

STUDY DESIGN: Retrospective review of a prospectively collected database. OBJECTIVE: This study compares patient demographics, incidence of comorbidities, procedure-related complications, and mortality following primary vs. revision adult spinal deformity surgerySummary of Background Data. While adult spinal deformity (ASD) surgery has been extensively investigated, no previous study has provided nationwide estimates of patient characteristics and procedure-related complications for primary vs. revision spinal deformity surgery comparatively. METHODS: Nationwide Inpatient Sample data collected between 2001 and 2010 was analyzed. Discharges with procedural codes for anterior and/or posterior thoracic and/or lumbar spinal fusion and refusion were included for patients aged 25+ and 4+ levels fused with any diagnoses specific for scoliosis. Patient demographics, comorbidity and procedure-related complications incidence were determined for primary vs. revision cohorts. Multivariate analysis reported as (OR [95% CI]). RESULTS: Discharges for 9133 primary and 850 revision cases were identified. Patients differed on the basis of demographic and hospital data. Average comorbidity indices for the cohorts were similar (p = 0.580), as was in-hospital mortality (p = 0.163). The incidence of procedure-related complications was higher for the revision cohort (46.96% vs. 71.97%, p = 0.001). The mean hospital course for the revision cohort was longer (6.37 vs. 7.13 days, p<0.0001). Revisions had an increased risk of complications involving the nervous system (1.34[1.10-1.6]), hematoma/seroma formation (2.31[1.92-2.78]), accidental vessel or nerve puncture (1.44[1.29-1.61]), wound dehiscence (2.18[1.48-3.21]), post-op infection (3.10[2.50-3.85]) and ARDS complications (1.43[1.28-1.60]). The primary cohort had a decreased risk for GI (0.65[0.55-0.76]) and GU complications (0.71[0.51-0.99]). CONCLUSIONS: Relative to primary cases, those undergoing revision correction of spinal deformity have a higher risk of many procedure-related complications with a longer hospital course despite similar baseline comorbidity burden and in-hospital mortality rate. This study provides clinically useful data for surgeons to educate patients at risk for morbidity and mortality and direct future research to improve outcomes.

BACKGROUND: Lumbar discectomy and laminectomy in patients with intervertebral disc herniation (IDH) is common, with variable reported reoperation rates. Our study examined which baseline characteristics might be risk factors for reoperation and compared outcomes between patients who underwent reoperation and those who did not. METHODS: We performed a retrospective subgroup analysis of patients from the IDH arm of the Spine Patient Outcomes Research Trial (SPORT) randomized and observational cohorts. We analyzed baseline characteristics and outcomes of patients who underwent reoperation and those who did not with use of data collected from enrollment through eight-years of follow-up after surgery. Follow-up times were measured from the time of surgery, and baseline covariates were updated to the follow-up immediately preceding the time of surgery for outcomes analyses. RESULTS: At eight years, the reoperation rate was 15% (691 no reoperation; 119 reoperation). Sixty-two percent of these patients underwent reoperation because of a recurrent disc herniation; 25%, because of a complication or other factor; and 11%, because of a new condition. The proportion of reoperations that were performed for a recurrent disc herniation ranged from 58% to 62% in the individual years. Older patients were less likely to have reoperation (p = 0.015), as were patients presenting with asymmetric motor weakness at baseline (p = 0.0003). Smoking, diabetes, obesity, Workers' Compensation, and clinical depression were not associated with a greater risk of reoperation. Scores on the Short Form (SF)-36 for bodily pain and physical functioning, the Oswestry Disability Index (ODI), and the Sciatica Bothersomeness Index as well as satisfaction with symptoms had improved less at the time of follow-up in the reoperation group (p < 0.001). CONCLUSIONS: In patients who underwent surgery for IDH, the overall reoperation rate was 15% at the eight-year follow-up. Patients of older age and patients presenting with asymmetric motor weakness were less likely to undergo a reoperation. Less improvement in patient-reported outcomes was noted in the reoperation group. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND CONTEXT: Cervical deformity (CD) is prevalent among patients with adult spinal deformity (ASD). The effect of baseline cervical alignment on achieving optimal thoracolumbar alignment in ASD surgery is unclear. PURPOSE: This study assesses the relationship between preoperative (preop) cervical spinal parameters and global alignment after thoracolumbar ASD surgery at 2-year follow-up. STUDY DESIGN/SETTING: This study is a retrospective review of a multicenter, prospective database. PATIENT SAMPLE: Surgical ASD patients with 2-year follow-up and cervical X-rays were included. OUTCOME MEASURES: The outcome measures were radiographic parameters and self-reported health-related quality-of-life measures (Short-Form 36 [SF-36], Oswestry Disability Index [ODI], and Scoliosis Research Society 22 [SRS-22]). METHODS: Surgical ASD patients of 18 years and older with scoliosis greater than or equal to 20 degrees and one of the following radiographic parameters were included: sagittal vertical axis (SVA) greater than or equal to 5 cm, pelvic tilt (PT) greater than or equal to 25 degrees , or thoracic kyphosis (TK) greater than 60 degrees . The SRS-Schwab sagittal modifiers (PT, global alignment, and pelvic incidence and lumbar lordosis [PI-LL]) were assessed at 2-year postoperatively as either normal ("0") or abnormal ("+" or "++"). Patients were classified in the aligned group (AG) or malaligned group (MG) at 2-year follow-up if all three sagittal modifiers were normal or abnormal, respectively. Patients were assessed for CD based on the following criteria: C2-C7 SVA greater than 4 cm, C2-C7 SVA less than 4 cm, cervical kyphosis (CL greater than 0), cervical lordosis (CL less than 0), any deformity (C2-C7 SVA greater than 4 cm or CL greater than 0), and both CD (C2-C7 SVA greater than 4 cm and CL greater than 0). Univariate testing was performed using t or chi-square test, looking at the following preop parameters: CD, C2-C7 SVA, C2-T3 SVA, CL, T1 slope (T1S), T1S-CL, C2-T3 angle, LL, TK, PT, C7-S1 SVA, and PI-LL. RESULTS: One hundred four patients met the initial inclusion criteria with 70 in the AG and 34 in MG. Preoperative, patients in the MG had a higher CL (11.7 vs. 4.9, p=.03), higher C2-T3 angle (13.59 vs 4.9 p=.01), higher PT (p<.0001), higher SVA (p<.0001), and higher PI-LL (p<.0001) compared with the AG. Interestingly, the prevalence of CD at baseline was similar for both groups. There was no statistically significant difference among groups in the amount of improvement more than 2 years on the ODI or the Physical Component Summary of SF-36. CONCLUSIONS: Patients with sagittal spinal malalignment associated with significant cervical compensatory lordosis are at increased risk of realignment failure at 2-year follow-up. Assessment of the degree of cervical compensation may be helpful in preop evaluation to assist in realignment outcome prediction.

BACKGROUND: Few studies have provided nationwide estimates of patient characteristics and procedure-related complications, or examined postsurgical outcomes for patients with cervical spondylotic myelopathy (CSM) comparatively with respect to surgical approach. The objective of this study is to identify patients at risk for morbidity and mortality directly related with the selected approach, report an overall nation-wide complication rate for each approach against which surgeons can compare themselves, and direct future research to improve patient outcomes. METHODS: Patients surgically treated for CSM were retrospectively identified using ICD-9-CM codes from the Nationwide Inpatient Sample (NIS) database. Four cohorts were compared for demographics and hospital system-related data: anterior (ACDF, ACCF), posterior decompression without fusion, decompression with posterior fusion, and combined anterior-posterior. Multivariate analysis was also used to determine the odds ratio of morbidity and mortality among the cohorts. RESULTS: 54,416 discharges were identified between 2001 and 2010: 34,400 anterior, 9,014 decompression procedures without fusion, 8,741 decompression procedures with posterior fusion, and 2,261 combined anterior-posterior. Groups were statistically different with respect to age, length of hospital stay, mortality, and complications. Groups were statistically different for Deyo score except between posterior decompression only and combined approaches. Using multivariate analysis and adjusting for covariates, the combined (2.74[2.18-3.44]) and laminectomy (1.22[1.04-1.44]) cohorts had an increased risk of mortality when compared to anterior alone. CONCLUSION: These findings are the first to determine the rates and odds of perioperative risks directly related to combined anterior-posterior procedures. This study provides clinically useful data for surgeons to educate patients and direct future research to improve patient outcomes.

PURPOSE: The aim of this study is to report and quantify the associated factors for morbidity and mortality following surgical management of cervical spondylotic myelopathy (CSM). METHODS: The Nationwide Inpatient Sample (NIS) database was use to retrospectively review all patients over 25 years of age with a diagnosis of CSM who underwent anterior and/or posterior cervical fusion or laminoplasty between 2001 and 2010. The main outcome measures were total procedure-related complications and mortality. Multivariate regression analysis was used to identify demographic, comorbidity, and surgical parameters associated with increased morbidity and mortality risk [reported as: OR (95 % CI)]. RESULTS: A total of 54,348 patients underwent surgical intervention for CSM with an overall morbidity rate of 9.83 % and mortality rate of 0.43 %. Comorbidities found to be associated with an increased complication rate included: pulmonary circulation disorders [6.92 (5.91-8.12)], pathologic weight loss [3.42 (3.00-3.90)], and electrolyte imbalance [2.82 (2.65-3.01)]. Comorbidities found to be associated with an increased mortality rate included: congestive heart failure [4.59 (3.62-5.82)], pulmonary circulation disorders [11.29 (8.24-15.47)], and pathologic weight loss [5.43 (4.07-7.26)]. Alternatively, hypertension [0.56 (0.46-0.67)] and obesity [0.36 (0.22-0.61)] were found to confer a decreased risk of mortality. Increased morbidity and mortality rates were also identified for fusions of 4-8 levels [morbidity: 1.55 (1.48-1.62), mortality: 1.80 (1.48-2.18)] and for age >65 years [morbidity: 1.65 (1.57-1.72), mortality: 2.74 (2.25-3.34)]. An increased morbidity rate was found for posterior-only [1.55 (1.47-1.63)] and combined anterior and posterior fusions [3.20 (2.98-3.43)], and an increased mortality rate was identified for posterior-only fusions [1.87 (1.40-2.49)]. Although revision fusions were associated with an increased morbidity rate [1.81 (1.64-2.00)], they were associated with a decreased rate of mortality [0.24 (0.10-0.59)]. CONCLUSION: The NIS database was used to provide national estimates of morbidity and mortality following surgical management of CSM in the United States. Several comorbidities, as well as demographic and surgical parameters, were identified as associated factors.

BACKGROUND: Our clinical understanding of os odontoideum (OO) remains incomplete. Congenital and traumatic causes have been proposed and advocated. Clinical presentations range from asymptomatic to axial pain to myelopathy or vertebral-basilar ischemia. A consensus for surgical management exists for those found to have an unstable atlantoaxial complex or symptomatic cranial-vertebral junction compression. OBJECTIVE: To evaluate the clinical presentation and surgical outcomes of patients with OO and an unstable atlantoaxial complex or symptomatic cranial-vertebral junction compression. METHODS: Patients with a diagnosis of OO who underwent surgical management were included. Patients were excluded on the basis of previous C2 fracture, Fielding diagnostic criteria, and inadequate follow-up. History of trauma and presenting symptoms were assessed. Clinical and neurological improvements were measured with the use of patient satisfaction scores and the Japanese Orthopaedic Association scores. Fusion status was documented with the use of radiographs and computed tomographic imaging. RESULTS: Of 279 patients, 112 reported a history of cranial-vertebral junction trauma, whereas 28 were diagnosed with congenital malformations. Clinically, 84.9% of patients presented with myelopathy, with pain presented in 42.6%. Atlantoaxial fixation was performed in 240 patients, occiput-to-C2 fixation in 35 patients, and extended occipito-cervical fixation in 4 patients. Mean follow-up was 40.3 months. Complications were reported in 2.4% of patients. Japanese Orthopaedic Association scores improved from a preoperative mean of 12.4 to 14.8. Two hundred thirty-five patients (77.7%) improved, with 30 patients experiencing no change in symptoms and 14 patients deteriorating. Fusion was achieved in 96.8% of patients. CONCLUSION: Our data reveal that surgical treatment for OO using the indications and techniques delineated is associated with high satisfaction rates, improved functional scores, and high fusion rates with low complication rates. ABBREVIATIONS: AAI, atlantoaxial instabilityJOA, Japanese Orthopaedic AssociationOO, os odontoideum.