Temporary fusionless posterior occipitocervical fixation for a proximal junctional type II odontoid fracture after previous C2-pelvis fusion: case report, description of a new surgical technique, and review of the literature.

PURPOSE: Axial fractures in patients with a previous C2-pelvis posterior instrumented fusion are rare and may be challenging to manage. Motion preservation in the axial spine for these patients is important, as the C1-2 and Occipit-C1 joints are their only remaining mobile spinal segments. In this unique report, we present for the first time the use of a fusionless occipitocervical operation for the treatment of a type II odontoid fracture and unilateral C2 pars fracture adjacent to a previous C2-pelvis posterior instrumented fusion. METHODS: Case report. RESULTS: Three years after proximal extension of a T3-pelvis posterior instrumented fusion to C2, the patient sustained a displaced odontoid fracture and unilateral C2 pars fracture after a mechanical fall. She underwent fracture stabilization with extension of instrumentation to the occiput. No attempt at fusion was performed. Post-operatively, she was distraught by severely limited neck range of motion, which was reflected in worsening of health-related quality of life (HRQoL) scores. The fracture healed uneventfully after which the instrumentation from the occiput and C1 were removed, which resulted in improvement of neck range of motion. Two years post-operatively, HRQoL scores showed minimal neck disability (NDI 12), no neck or arm pain (VAS 0), and outstanding general health (EQ-5D 85 out of 100, SF-36 PCS 35.3, SF-36 MCS 41.1). CONCLUSION: In this one patient, instrumentation without fusion allowed for successful and timely union of a displaced odontoid fracture in a patient with a previous C2-pelvis fusion. Axial range of motion was preserved after instrumentation removal.

Circumferential fusion for degenerative lumbar spondylolisthesis complicated by distal junctional grade 4 spondylolisthesis in the sub-acute post-operative setting.

INTRODUCTION: Surgical management for lumbar stenosis is generally safe and provides significant improvements in pain, disability, and function. Successful lumbar decompression hinges on removing an appropriate amount of lamina and other compressive pathology in the lateral recess. Too little bony decompression can result in persistent pain and disability, while over resection of the pars and/or facets may jeopardize spinal stability. CASE REPORT: In this unique report, we present for the first time an acute iatrogenic grade 4 L5-S1 spondylolisthesis distal to a L3-5 laminectomy and circumferential instrumented fusion due to bilateral iatrogenic L5 pars fractures and its management and clinical outcomes after revision operation. The patient presented with worsening pain, neurologic compromise, and severe sagittal imbalance. The iatrogenic, high-grade spondylolisthesis was urgently addressed with a L5-S1 anterior lumbar interbody fusion and extension of posterior instrumentation to the pelvis, which resulted in considerable pain relief, resolution of neurologic deficits, and reconstitution of acceptable sagittal imbalance. CONCLUSION: All attempts during a lumbar decompression should be made to prevent iatrogenic pars fractures, as they may result in severe sagittal imbalance, neurologic compromise, and persistent disability. Iatrogenic, high-grade L5-S1 spondylolisthesis can be successfully treated with reduction using circumferential fusion of the lumbosacral junction.

Asymmetric C7 pedicle subtraction osteotomy for correction of rigid cervical coronal imbalance secondary to post-traumatic heterotopic ossification: a case report, description of a novel surgical technique, and literature review.

PURPOSE: Deformities of the cervical spine are uncommon in the coronal plane. In this report, a unique case of a 31-year-old male with a fixed, 30° left coronal deformity due to heterotopic ossification 3 years status post poly-trauma was treated with an asymmetric C7 pedicle subtraction osteotomy (PSO). METHODS: Case report. RESULTS: Pre-operatively, the patient had a fixed 45-degree left tilt of his neck and radiographs demonstrated a rigid 30° scoliosis, 7 cm coronal imbalance, and 4 cm negative sagittal balance, diffuse bridging bone between the spinous processes and the facet joints of C5 to T1 bilaterally. An asymmetric C7 PSO with C2-T3 posterior spinal fusion was completed without complication. There was residual 9° coronal deformity, 2.9 cm left coronal imbalance, and 2.3 cm sagittal imbalance. He had a marked improvement in his function, as assessed by the SF-36 physical component score (pre-op 31.1; post-op 44.7) and mental component score (pre-op 46.0; post-op 66.8). Post-operatively, neck disability index scores also improved (pre-op 38; post-op 16). Although the patient passed away from a drug overdose 14 months post-operatively, he did not report neck pain, he had not sought evaluation from another physician for his neck, and he had not undergone a subsequent neck operation before his passing. CONCLUSION: In this one patient, an asymmetric C7 PSO was performed safely. While it was effective in addressing a fixed cervical coronal imbalance, its efficacy and safety profile should be confirmed in larger cohorts.

Clonal precursor of bone, cartilage, and hematopoietic niche stromal cells.

Organs are composites of tissue types with diverse developmental origins, and they rely on distinct stem and progenitor cells to meet physiological demands for cellular production and homeostasis. How diverse stem cell activity is coordinated within organs is not well understood. Here we describe a lineage-restricted, self-renewing common skeletal progenitor (bone, cartilage, stromal progenitor; BCSP) isolated from limb bones and bone marrow tissue of fetal, neonatal, and adult mice. The BCSP clonally produces chondrocytes (cartilage-forming) and osteogenic (bone-forming) cells and at least three subsets of stromal cells that exhibit differential expression of cell surface markers, including CD105 (or endoglin), Thy1 [or CD90 (cluster of differentiation 90)], and 6C3 [ENPEP glutamyl aminopeptidase (aminopeptidase A)]. These three stromal subsets exhibit differential capacities to support hematopoietic (blood-forming) stem and progenitor cells. Although the 6C3-expressing subset demonstrates functional stem cell niche activity by maintaining primitive hematopoietic stem cell (HSC) renewal in vitro, the other stromal populations promote HSC differentiation to more committed lines of hematopoiesis, such as the B-cell lineage. Gene expression analysis and microscopic studies further reveal a microenvironment in which CD105-, Thy1-, and 6C3-expressing marrow stroma collaborate to provide cytokine signaling to HSCs and more committed hematopoietic progenitors. As a result, within the context of bone as a blood-forming organ, the BCSP plays a critical role in supporting hematopoiesis through its generation of diverse osteogenic and hematopoietic-promoting stroma, including HSC supportive 6C3(+) niche cells.

Prior Lumbar Spinal Arthrodesis Increases Risk of Prosthetic-Related Complication in Total Hip Arthroplasty.

BACKGROUND: Degenerative hip disorders often coexist with degenerative changes of the lumbar spine. Limited data on this patient population suggest inferior functional improvement and pain relief after surgical management. The purpose of this study is to compare the rates of prosthetic-related complication after primary total hip arthroplasty (THA) in patients with and without prior lumbar spine arthrodesis (SA). METHODS: Medicare patients (n = 811,601) undergoing primary THA were identified and grouped by length of prior SA (no fusion, 1-2 levels fused [S-SAHA], and ≥3 levels fused [L-SAHA]). RESULTS: Compared with controls, patients with prior SA had significantly higher rates of complications including dislocation (control: 2.36%; S-SAHA: 4.26%; and L-SAHA: 7.51%), revision (control: 3.43%, S-SAHA: 5.55%, and L-SAHA: 7.77%), loosening (control: 1.33%, S-SAHA: 2.10%, and L-SAHA: 3.04%), and any prosthetic-related complication (control: 7.33%, S-SAHA: 11.15% [relative risk: 1.52], and L-SAHA: 14.16% [relative risk: 1.93]) within 24 months (P < .001). CONCLUSION: The interplay of coexisting degenerative hip and spine disease deserves further attention of both arthroplasty and spine surgeons.

Three-column osteotomies of the lower cervical and upper thoracic spine: comparison of early outcomes, radiographic parameters, and peri-operative complications in 48 patients.

PURPOSE: To evaluate and compare early radiographic and clinical outcomes of lower cervical and upper thoracic three-column osteotomies (3CO) for cervicothoracic kyphosis correction. METHODS: Patients who underwent 3CO at the cervicothoracic junction at two institutions were retrospectively reviewed. Patients were divided into two groups: lower cervical osteotomy (LCO) and upper thoracic osteotomy (UTO: T1-T5). Operative data, radiographic alignment, peri-operative complications, and clinical outcomes were compared between the groups. RESULTS: Forty-eight patients [male: 24; female: 24; average age 61 years (range 18-92 years); mean follow-up: 22 months] met inclusion criteria. A total of 24 pedicle subtraction osteotomies and 24 vertebral column resections were performed. Compared to UTO, LCO operative time was significantly shorter, average ICU and hospital stays were significantly longer, and the average pre-operative cervical sagittal vertical axis (SVA) and kyphosis were significantly greater (p < 0.05). For both groups, there was significant improvement in cervical SVA, cervical lordosis, segmental angle, Neck Disability Index (NDI), SRS Activity, and pain visual analog score (p < 0.05). Reoperation rates were similar between the groups (LCO: 33.3 %; UTO: 18 %, p = 0.28). Significantly, more patients required tracheostomy/gastrostomy tubes after LCO (3 vs. 0 in the UTO group, p = 0.03). CONCLUSIONS: Three-column posterior osteotomies at the cervicothoracic junction restored regional sagittal alignment and improved quality of life in this series of patients with rigid cervicothoracic deformity, albeit with high complication rates. Lower cervical osteotomies provided greater cervical SVA correction and were shorter operations, although they were associated with more complications and longer hospital and ICU stays compared to upper thoracic osteotomies.

The association between cervical spine pathology and rotator cuff dysfunction.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate the relationship between cervical spine (C-spine) and rotator cuff (RTC) pathology. SUMMARY OF BACKGROUND DATA: Cervical spine and RTC pathology cause significant shoulder pain in isolation and in tandem, but there is limited information about the relationship between these 2 entities. METHODS: Patients with a diagnosis of C-spine and/or RTC pathology between 2005 and 2011 were identified using a large national database composed of private payer as well as Medicare patient records. Patients with concomitant C-spine and RTC diagnoses were then stratified by age group and sex. Patients with lumbar spine (L-spine) and RTC pathology were used as a comparative group, and multivariate logistic regression was used for statistical analysis. RESULTS: Concomitant C-spine and RTC diagnoses were identified in 86,928 patients representing 13% of 679,112 patients with a RTC diagnosis and 16% of 531,177 patients with a C-spine diagnosis. The association between C-spine and RTC pathology increased significantly with age as RTC diagnoses were present in 13% of patients with C-spine pathology younger than 60 years old but increased to 25% in C-spine patients older than 60 years (P<0.0001). For patients over 60 years old who developed a new C-spine diagnosis, 11% would develop a new RTC diagnosis or undergo an operation for a RTC disorder within 5 years. Lumbar diagnosis codes (2,297,480 patients) were over 4 times more common than C-spine codes but RTC pathology had a significantly higher correlation with C-spine pathology than L-spine pathology (odds ratio, 2.32) and patients with C-spine pathology were more likely to develop new rotator cuff pathology (odds ratio, 1.53). CONCLUSIONS: The association between cervical spine and RTC pathology is significantly greater than that between L-spine and RTC pathology and increases substantially with patient age. Further studies are needed to elucidate the cause of this relationship.

Comparison of T1rho relaxation times between ACL-reconstructed knees and contralateral uninjured knees.

PURPOSE: The goal of this study is to compare the cartilage of anterior cruciate ligament (ACL)-reconstructed and uninjured contralateral knees using T 1ρ MRI 12-16 months after ACL reconstructions. METHODS: Eighteen patients with ACL-reconstructed knees (10 women, 8 men, mean age = 38.3 ± 7.8 years) were studied using 3T MRI. Injured and contralateral knee MR studies were acquired 12-16 months post-operatively. Cartilage sub-compartment T 1ρ values of each injured knee were compared with the contralateral knee's values. Subgroup analysis of sub-compartment T 1ρ values in both knees was performed between patients with and without meniscal tears at the time of ACL reconstruction using a paired Student's t test. RESULTS: In ACL-injured knees, the T 1ρ values of the medial tibia (MT) and medial femoral condyle (MFC) were significantly elevated at 12-16 months follow-up compared to contralateral knees. Patients with a medial meniscal tear had higher MFC and MT T 1ρ values compared to respective regions in contralateral knees. Patients with lateral meniscal tears had higher lateral femoral condyle and LT T 1ρ values compared to respective regions in contralateral knees. There were no differences between the injured and contralateral knees of patients without meniscal tears. CONCLUSIONS: T 1ρ MRI can detect significant changes in the medial compartments' cartilage matrix of ACL-reconstructed knees at 1 year post-operatively compared to contralateral knees. The presence of a meniscal tear at the time of ACL reconstruction is a risk factor for cartilage matrix degeneration in the femorotibial compartments on the same side as the meniscal tear.

Evaluation of bone bruises and associated cartilage in anterior cruciate ligament-injured and -reconstructed knees using quantitative t(1ρ) magnetic resonance imaging: 1-year cohort study.

PURPOSE: To quantitate bone marrow edema-like lesions (BMELs) and the radiologic properties of cartilage in knees with acute anterior cruciate ligament (ACL) injuries using T(1ρ) magnetic resonance imaging over a 1-year period. METHODS: Nine patients with ACL injuries were studied. Magnetic resonance imaging scans were acquired within 8 weeks of the injury, after which ACL reconstruction surgery was performed. Images were then acquired 0.5, 6, and 12 months after reconstructions. The volume and signal intensity of BMELs were quantified at baseline and follow-up examinations. T(1ρ) values were quantified in cartilage overlying the BMEL (OC) and compared with surrounding cartilage at all time points. RESULTS: BMELs were most commonly found in the lateral tibia and lateral femoral condyle. Nearly 50% of BMELs resolved over a 1-year period. The T(1ρ) values of the OC in the lateral tibia, medial tibia, and medial femoral condyle were elevated compared with respective regions in surrounding cartilage at all time points; the difference was significant only in the lateral tibia (P < .05). The opposite results were found in the lateral femoral condyle. For the medial tibia and medial femoral condyle, none of the time periods was significantly different. The percent increase in T(1ρ) values of OC in the lateral tibia was significantly correlated with BMEL volume (r = 0.74, P < .05). At 1 year, the OC in the lateral tibia, medial tibia, and medial femoral condyle showed increased T(1ρ) values despite improvement of BMEL. CONCLUSIONS: In patients after ACL tear and reconstruction, (1) the cartilage overlying BMEL in the lateral tibia experiences persistent T(1ρ) signal changes immediately after acute injuries and at 1-year follow-up despite BMEL improvement, (2) the superficial layers of the overlying cartilage show greater matrix damage than the deep layers, and (3) the volume of the BMEL may predict the severity of the overlying matrix's damage in the lateral tibia. T(1ρ) is capable of quantitatively and noninvasively monitoring this damage and detecting early cartilage changes in the lateral tibia over time. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Correlation of Paraspinal Muscle Mass With Decompensation of Sagittal Adult Spinal Deformity After Setting of Fatigue Post 10-Minute Walk.

OBJECTIVE: The purpose of this study was to investigate the changes in spinopelvic parameters before and after the setting of muscle fatigue along with its correlation with pre-existing paraspinal and psoas muscle mass. METHODS: Single-center retrospective review of prospectively collected data was conducted on 145-adults with symptomatic loss of lumbar lordosis (LL). Radiographs were taken before and after walking for 10 minutes. Magnetic resonance imaging was used to calculate paraspinal muscle (PSM) cross-sectional area (CSA), mean signal intensity, fatty infiltration (FI), and lean muscle mass at thoracolumbar junction (T12) and lower lumbar level (L4). Psoas CSA was calculated at L3. Patients were divided into 2 groups namely compensated sagittal deformity (CSD) (SVA ≤ 4 cm, PT > 20°) and decompensated sagittal deformity (DSD) (SVA > 4 cm, PT > 20°) based on prewalk measurements. RESULTS: Initial mean SVA was 1.8 cm and 11 cm for CSD and DSD respectively (p < 0.01). After walking, significant deteriorations in SVA, PT-LL (p < 0.01) were observed in CSD without significant change in thoracic kyphosis (TK). All sagittal parameters in DSD deteriorated significantly. DSD group had significantly poorer PSM quality at T12 and L4 compared to CSD group. In CSD group, sagittal decompensation correlated with muscle quality, i.e. , decreases in LL (ΔLL) correlated with CSA of PSM/vertebral body (VB) at L4 (r = -0.412, p = 0.046) while increases in TK (ΔTK) correlated with CSA of PSM/VB at T12 (r = 0.477, p = 0.018). ΔSVA and ΔPT correlated with FI at L4 (r = 0.577, p = 0.003 and r = -0.407, p = 0.048, respectively). DSD group, had weak correlations (-0.3 < r < -0.1) between changes in sagittal and PSM parameters. CONCLUSION: PSM quality in adults with spinal deformity correlates with patients' ability to maintain an upright posture and sagittal decompensation after walking for 10 minutes.

T(1ρ) and T(2) quantitative magnetic resonance imaging analysis of cartilage regeneration following microfracture and mosaicplasty cartilage resurfacing procedures.

PURPOSE: To examine T(1ρ) (T1rho) and T(2) quantitative magnetic resonance imaging (MRI) in evaluating cartilage regeneration following microfracture (MFx) and mosaicplasty (MOS) cartilage resurfacing procedures. MATERIALS AND METHODS: Eighteen patients underwent MFx and eight patients underwent MOS to treat symptomatic focal cartilage defects. Quantitative T(1ρ) and T(2) maps were acquired at 3-6 months and 1 year after surgery. The area of resurfacing was identified, and T(1ρ) and T(2) values for the regenerated tissue (RT) and normal cartilage (NC) were acquired. RT/NC ratios were calculated to standardize absolute T(1ρ) and T(2) values. Data were prospective, cross-sectional, and nonrandomized. RESULTS: T(1ρ) and T(2) showed good reanalysis reproducibility for RT and NC. Significant differences between RT and NC were present following MFx at 3-6 months for T(1ρ) and T(2) values as well as following MOS at 3-6 months and 1 year for T(1ρ) values. Following MFx, the T(2) RT/NC ratio was significantly different between 3-6 months and 1 year (P = 0.02), while the T(1ρ) RT/NC ratio approached significance (P = 0.07). Following MOS, the T(1ρ) and T(2) RT/NC ratios were not significantly different between the two timepoints. CONCLUSION: T(1ρ) and T(2) MRI are complementary and reproducible methods for quantitatively and noninvasively monitoring regeneration of RT following MFx and MOS.

Preoperative CT Angiography Informs Instrumentation in Anterior Spine Surgery for Idiopathic Scoliosis.

The objective of this study is to evaluate whether the artery of Adamkiewicz localization with preoperative CT angiography influences anterior spinal instrumentation. Methods: Children with idiopathic scoliosis who underwent anterior instrumentation and with a preoperative CT angiography were evaluated retrospectively. Data included curve type, artery of Adamkiewicz level/laterality, surgical approach laterality, number of instrumented levels and segmental vessels ligated, intraoperative neuromonitoring changes, and postoperative neural complications. Results: Thirty-nine girls and eight boys (mean age 12 years [6.7 to 16.8 years]) were analyzed. Instrumented curves indicate 28 thoracic, 14 thoracolumbar, and seven double major. The artery of Adamkiewicz: T6 (left-1), T8 (left-1), T9 (left-4/right-2), T10 (left-11/right-4), T11 (left-4/right-4), T12 (left-1/right-2), L1 (left-2/right-1), and L2 (left-3/right-2). Four had bilateral dominant segmentals, whereas in nine patients, none was identified. T10 (32%) and left side (57%) were most frequent. On average, 7.1 (4 to 11) segmentals were ligated per case (total 355). Dominant vessels were ipsilateral to/within instrumentation levels in 30%. Discussion: In children with idiopathic scoliosis who underwent anterior instrumentation, the artery of Adamkiewicz was identified on the left in >50% and at T10 in 32%. In one-third of the patients, the artery was within intended surgical levels and resulted in instrumentation modification.

Ethnic Variation in Satisfaction and Appearance Concerns in Adolescents With Idiopathic Scoliosis Undergoing Posterior Spinal Fusion With Instrumentation.

STUDY DESIGN: Cohort analysis. OBJECTIVE: Document satisfaction with management and appearance concerns in children of different ethnicity who underwent spinal fusion/instrumentation for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Scoliosis Research Society Questionnaire (SRS-30) outcomes in AIS indicate a link between appearance and satisfaction as well as ethnic variation in appearance domain. Exploration of these findings in the Scoliosis Appearance Questionnaire (SAQ) will allow better understanding of ethnic variation in appearance concerns. METHODS: Children with AIS who underwent posterior-only operations and completed the SAQ's question 31 were identified. Univariate logistic regression of SAQ questions 12-30 was used to assess relationships with ethnicity. RESULTS: 1,977 children [boys: 281, girls: 1,290, unspecified: 406; average age 15.1 ± 2.0 years preoperatively and 817 children (boys: 113, girls: 569, unspecified: 135; average age 15.1 ± 2.0 years) at 2 years' follow-up met inclusion criteria. The majority were Caucasian (57.3%). Few were Hispanic (3.4%). Preoperatively, the largest percentage of patients in each ethnic group answered "very true" to "wanting to be more even." Preoperatively, Asians were least likely to be concerned about evenness of shoulders, hips, waist, ribs, and chest in back (p < .05); however, they expressed greatest concern about height (p < .05). African Americans and Hispanics were more likely to be concerned about breast evenness and anterior chest and looking better in clothes (p < .05). African Americans were most concerned about overall evenness and evenness of shoulders, hips, waist, ribs, posterior chest, leg length, and looking more attractive (p < .05). Surgical scar was most important postoperatively for all ethnicities. African Americans and Hispanics were more self-conscious about scar (p < .05). African Americans were most likely to want to be more even and have more even shoulders, hips, waist, leg lengths, ribs, breasts, and chest postoperatively. CONCLUSIONS: Ethnicity influenced appearance concerns in pre- and postoperative SAQ evaluation. Ethnic variation in appearance concerns should be taken into account and differentiated when counseling patients about AIS and surgical correction. LEVEL OF EVIDENCE: Level III.

Correlation Between Lumbopelvic and Sagittal Parameters and Health-Related Quality of Life in Adults With Lumbosacral Spondylolisthesis.

STUDY DESIGN: Secondary analysis of prospective, multicenter data. OBJECTIVE: To evaluate impact of sagittal parameters on health-related quality of life (HRQoL) in adults with lumbosacral spondylolisthesis. METHODS: Adults with unoperated lumbosacral spondylolisthesis were identified in the Spinal Deformity Study Group database. Pearson's correlations were calculated between SF-12 (Short Form-12)/Scoliosis Research Society-30 (SRS-30) scores and radiographic parameters (C7 sagittal vertical axis [SVA] deviation, T1 pelvic angle, pelvic tilt [PT], pelvic incidence, sacral slope, slip angle, Meyerding slip grade, Labelle classification). Main effects linear regression models measured association between individual health status measures and individual radiographic predictor variables. RESULTS: Forty-five patients were analyzed (male, 15; female, 30; average age 40.5 ± 18.7 years; 14 low-grade, 31 high-grade). For low-grade slips, SVA had strong negative correlations with SF-12 mental component score (MCS), SRS-30 appearance, mental, and satisfaction domains (r = -0.57, r = -0.60, r = -0.58, r = -0.53, respectively; P < .05). For high-grade slips, slip angle had a moderate negative correlation with SF-12 MCS (r = -0.36; P = .05) and SVA had strong negative correlations with SF-12 physical component score (PCS), SRS-30 appearance and activity domains (r = -0.48, r = -0.48, r = -0.45; P < .05) and a moderate negative correlation with SRS-30 total (r = -0.37; P < .05). T1 pelvic angle had a moderate negative correlation with SF-12 PCS and SRS-30 appearance (r = -0.37, r = -0.36; P ≤ .05). For every 1° increase in PT, there was a 0.04-point decrease in SRS appearance, 0.05-point decrease in SRS activity, 0.06-point decrease in SRS satisfaction, and 0.04-point decrease in SRS total score (P < .05). CONCLUSION: Lumbosacral spondylolisthesis in adults negatively affects HRQoL. Multiple radiographic sagittal parameters negatively affect HRQoLs for patients with low- and high-grade slips. Improvement of sagittal parameters is an important goal of surgery for adults with lumbosacral spondylolisthesis.

Quantitative Assessment of the Anatomical Footprint of the C1 Pedicle Relative to the Lateral Mass: A Guide for C1 Lateral Mass Fixation.

STUDY DESIGN: Anatomic study. OBJECTIVES: To determine the relationship of the anatomical footprint of the C1 pedicle relative to the lateral mass (LM). METHODS: Anatomic measurements were made on fresh frozen human cadaveric C1 specimens: pedicle width/height, LM width/height (minimum/maximum), LM depth, distance between LM's medial aspect and pedicle's medial border, distance between LM's lateral aspect to pedicle's lateral border, distance between pedicle's inferior aspect and LM's inferior border, distance between arch's midline and pedicle's medial border. The percentage of LM medial to the pedicle and the distance from the center of the LM to the pedicle's medial wall were calculated. RESULTS: A total of 42 LM were analyzed. The C1 pedicle's lateral aspect was nearly confluent with the LM's lateral border. Average pedicle width was 9.0 ± 1.1 mm, and average pedicle height was 5.0 ± 1.1 mm. Average LM width and depth were 17.0 ± 1.6 and 17.2 ± 1.6 mm, respectively. There was 6.9 ± 1.5 mm of bone medial to the medial C1 pedicle, which constituted 41% ± 9% of the LM's width. The distance from C1 arch's midline to the medial pedicle was 13.5 ± 2.0 mm. The LM's center was 1.6 ± 1 mm lateral to the medial pedicle wall. There was on average 3.5 ± 0.6 mm of the LM inferior to the pedicle inferior border. CONCLUSIONS: The center of the lateral mass is 1.6 ± 1 mm lateral to the medial wall of the C1 pedicle and approximately 15 mm from the midline. There is 6.9 ± 1.5 mm of bone medial to the medial C1 pedicle. Thus, the medial aspect of C1 pedicle may be used as an anatomic reference for locating the center of the C1 LM for screw fixation.

Comparative analysis of 3 surgical strategies for adult spinal deformity with mild to moderate sagittal imbalance.

OBJECTIVE Surgical treatment of adult spinal deformity (ASD) is an effective endeavor that can be accomplished using a variety of surgical strategies. Here, the authors assess and compare radiographic data, complications, and health-related quality-of-life (HRQoL) outcome scores among patients with ASD who underwent a posterior spinal fixation (PSF)-only approach, a posterior approach combined with lateral lumbar interbody fusion (LLIF+PSF), or a posterior approach combined with anterior lumbar interbody fusion (ALIF+PSF). METHODS The medical records of consecutive adults who underwent thoracolumbar fusion for ASD between 2003 and 2013 at a single institution were reviewed. Included were patients who underwent instrumentation from the pelvis to L-1 or above, had a sagittal vertical axis (SVA) of < 10 cm, and underwent a minimum of 2 years' follow-up. Those who underwent a 3-column osteotomy were excluded. Three groups of patients were compared on the basis of the procedure performed, LLIF+PSF, ALIF+PSF, and PSF only. Perioperative spinal deformity parameters, complications, and HRQoL outcome scores (Oswestry Disability Index [ODI], Scoliosis Research Society 22-question Questionnaire [SRS-22], 36-Item Short Form Health Survey [SF-36], visual analog scale [VAS] for back/leg pain) from each group were assessed and compared with each other using ANOVA. The minimal clinically important differences used were -1.2 (VAS back pain), -1.6 (VAS leg pain), -15 (ODI), 0.587/0.375/0.8/0.42 (SRS-22 pain/function/self-image/mental health), and 5.2 (SF-36, physical component summary). RESULTS A total of 221 patients (58 LLIF, 91 ALIF, 72 PSF only) met the inclusion criteria. Average deformities consisted of a SVA of < 10 cm, a pelvic incidence-lumbar lordosis (LL) mismatch of > 10°, a pelvic tilt of > 20°, a lumbar Cobb angle of > 20°, and a thoracic Cobb angle of > 15°. Preoperative SVA, LL, pelvic incidence-LL mismatch, and lumbar and thoracic Cobb angles were similar among the groups. Patients in the PSF-only group had more comorbidities, those in the ALIF+PSF group were, on average, younger and had a lower body mass index than those in the LLIF+PSF group, and patients in the LLIF+PSF group had a significantly higher mean number of interbody fusion levels than those in the ALIF+PSF and PSF-only groups. At final follow-up, all radiographic parameters and the mean numbers of complications were similar among the groups. Patients in the LLIF+PSF group had proximal junctional kyphosis that required revision surgery significantly less often and fewer proximal junctional fractures and vertebral slips. All preoperative HRQoL scores were similar among the groups. After surgery, the LLIF+PSF group had a significantly lower ODI score, higher SRS-22 self-image/total scores, and greater achievement of the minimal clinically important difference for the SRS-22 pain score. CONCLUSIONS Satisfactory radiographic outcomes can be achieved similarly and adequately with these 3 surgical approaches for patients with ASD with mild to moderate sagittal deformity. Compared with patients treated with an ALIF+PSF or PSF-only surgical strategy, patients who underwent LLIF+PSF had lower rates of proximal junctional kyphosis and mechanical failure at the upper instrumented vertebra and less back pain, less disability, and better SRS-22 scores.

Autonomic dysreflexia caused by cervical stenosis.

INTRODUCTION: Autonomic dysreflexia (AD) is a well-known sequela of high spinal cord injuries (SCI). The characteristic episodic presentation is one of increased sympathetic tone: diaphoresis, hypertension, tachycardia, or reflex bradycardia. The episodes are triggered by visceral sensations and can last days to weeks. CASE PRESENTATION: This report presents the case of a 73-year-old male with cervical stenosis, with a longstanding history of "hot flashes" accompanied by dizziness, flushing and diaphoresis, and palpitations. The patient was evaluated extensively by cardiology, endocrinology, and neurology with no treatable pathology determined aside from the patient's cervical stenosis. The patient was diagnosed with autonomic dysreflexia caused by cervical spinal stenosis and underwent anterior cervical decompression and fusion (ACDF) at the stenotic C5-C6 level. He found near complete resolution of his autonomic symptoms. DISCUSSION: We hypothesize that the cervical compression caused a disruption in the regulatory control of the sympathetic preganglionic neurons resulting in the autonomic symptoms. Although numerous studies exist of patients with a traumatic onset of AD, to the best of our knowledge, this is the first case report in the literature of autonomic symptoms that stemmed from cervical stenosis. The purpose of this case report is to alert clinicians to a potential association between AD and spinal stenosis, which may exist outside the realm of SCI.

Anterior Versus Posterior Approaches for Odontoid Fracture Stabilization in Patients Older Than 65 Years: 30-day Morbidity and Mortality in a National Database.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To compare 30-day perioperative clinical outcomes of surgical odontoid stabilization by an anterior or posterior operative approach in elderly patients. SUMMARY OF BACKGROUND DATA: Surgical stabilization of odontoid fractures is superior to nonoperative management in geriatric patients. How elderly patients with odontoid fractures fare after anterior and posterior approaches, however, is not well defined. MATERIALS AND METHODS: Retrospective review of the prospectively collected American College of Surgeons National Surgical Quality Improvement Program database (2005-2013). Elderly patients (≥65 y) with odontoid fractures who underwent odontoid stabilization through anterior or posterior approaches were identified by International Classification of Diseases 9th Revision/Common Procedure Terminology codes. Exclusion criteria included concomitant subaxial spine surgery, instrumentation noncontiguous with the atlantoaxial interval, and combined approaches. Baseline demographics and perioperative details were compared. Adverse events, mortality, reoperation, discharge, and readmission rates within 30 days of operation were compared using bivariate and multivariate generalized linear regressions. RESULTS: One hundred forty-one patients (male-81; female-60; average age: 77.8±6.5 y; anterior approach-48; posterior approach-93) were analyzed. Patients scheduled to have a posterior approach had significantly more nonunions preoperatively and higher body mass indices. Operative times for posterior surgeries were significantly longer. Age, comorbidities, functional dependence, time to surgery, and length of hospital stay were similar between groups. There were no significant differences in the relative risk (RR) of the composite outcome of "any adverse event" after adjusting for differences in baseline characteristics. Patients who underwent an anterior approach were more likely to have an unplanned hospital readmission (RR=8.95; 95% confidence interval, 2.21-36.29; P=0.002) and have significantly more revision operations (RR=19.51; 95% confidence interval, 2.49-152.62; P=0.005) than patients who had a posterior operation. CONCLUSIONS: An anterior approach for odontoid fracture stabilization in patients ≥65 years old were associated with shorter operative times and greater RRs of unplanned readmissions and revision operations within 30 days of surgery relative to a posterior approach.

National Trends in the Surgical Management of Adolescent Idiopathic Scoliosis: Analysis of a National Estimate of 60,108 Children From the National Inpatient Sample Over a 13-Year Time Period in the United States.

STUDY DESIGN: Analysis of Nationwide Inpatient Sample (NIS). OBJECTIVE: Evaluate evolution of operative treatment of adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Spinal surgery is one of the most rapidly evolving branches of surgery. Changes in AIS operations are incompletely defined. METHODS: Children (10-18 years) with ICD-9 diagnosis of idiopathic scoliosis who underwent thoracic and/or lumbar spinal fusion identified in the NIS (1998-2011) were analyzed. Population-based utilization rates were calculated from US Census data. Patient demographics, surgical approach, operative techniques, complications during hospitalization, hospital stay length, and charges were analyzed. RESULTS: 60,108 children (46,256 girls, 13,776 boys, 76 gender not specified; average age 14.1 years) were identified. Thoracic fusions were the majority. Number of operations increased over time. For thoracic fusions, posterior operations significantly increased, whereas anterior and anterior/posterior operations decreased significantly. Although anterior operations for lumbar fusions declined, this was not as steep as thoracic. Use of autogenous bone graft (including iliac crest) significantly increased, which mirrored significant decreases in alternative fusion agents. Thoracoplasty significantly decreased, whereas osteotomy significantly increased. The average complication rate was 3.7%. Rates of blood transfusions, infection, and neural injury did not differ significantly from 1998 to 2011. Device-related complications increased significantly over time. Average lengths of hospital stay decreased significantly, whereas average total hospital charges increased significantly. CONCLUSIONS: In a representative sample of the US population from 1998 to 2011, operative approaches and techniques for AIS significantly changed. Anterior procedure is rarely performed for thoracic curves; lumbar curves continue to be treated with anterior and posterior approaches. Osteotomy and autogenous bone graft increased, while thoracoplasty decreased. Overall complication rates remain stable, whereas hospital lengths of stays decreased and charges increased.

Spinal Realignment for Adult Deformity: Three-column Osteotomies Alter Total Hip Acetabular Component Positioning.

INTRODUCTION: A goal of adult spinal deformity surgery is correction of sagittal imbalance by increasing lumbar lordosis (LL), allowing a previously retroverted pelvis to normalize as evidenced by decreases in pelvic tilt (PT). Realignment of pelvic orientation may alter the position of preexisting total hip arthroplasties (THAs). METHODS: Twenty-seven patients with unilateral THA who underwent thoracolumbar fusions for adult spinal deformity from the pelvis to L1 or above were retrospectively reviewed (levels fused, 10.3 [range, 6 to 17]; age, 70 ± 9 years). Comparisons of preoperative and postoperative spinal deformity parameters, acetabular tilt (AT), and acetabular cup abduction angle (CAA) were performed, with subgroup analysis for those who had undergone three-column osteotomy and those who had not. RESULTS: Preoperative deformity was severe, with findings of a sagittal vertical axis >9 cm, PT >25°, and pelvic incidence-LL >20°. Postoperatively, AT decreased significantly (-7° ± 10°; P < 0.001), signifying relative acetabular retroversion. Comparing patients with three-column osteotomy versus those without, AT changes were greater in those with three-column osteotomy (11° ± 7° and -2 ± 10°, respectively; P = 0.024). AT was significantly correlated with changes of PT (r = 0.704; P < 0.001) and LL (r = -0.481; P = 0.011). AT decreased (ie, retroverted) 1° for every 3.23° of LL or 1.13° of PT correction. The coronal plane CAA did not change substantially. DISCUSSION: Spinal deformity correction, with techniques such as three-column osteotomy, result in significant THA acetabular component repositioning in the sagittal plane. Resultant decreased AT (ie, retroversion) theoretically may affect tribology, wear, and joint stability and warrants further investigation.