The Mobi-C® cervical disc and other devices for two-level disc replacement: overview of its safety and efficacy.

INTRODUCTION: Cervical disc arthroplasty (CDA) has become an acceptable alternative for anterior cervical discectomy and fusion (ACDF) for a significant patient population with cervical radiculopathy and/or myelopathy secondary to degenerative changes in the cervical spine. There are sufficient mid- and long-term data supporting performance and safety of one-level CDA. With the success of single-level cervical CDA, considerable interest exists about CDA use for multilevel cervical degenerative disc disease (DDD). This review analyzes the safety and efficacy of two-level CDA for treatment of symptomatic cervical DDD with focus on the Mobi-C® Cervical Disc. AREAS COVERED: This review summarizes previously published articles in a literature search using keywords: 'two-level-anterior cervical arthrodesis; two-level anterior cervical decompression and fusion (ACDF); two-level cervical disc arthroplasty (CDA); two-level cervical total disc replacement; two-level symptomatic degenerative disc disease (DDD); Mobi-C® disc'. EXPERT OPINION: Two-level CDA with the Mobi-C® device demonstrated equivalent, and in certain aspects, favorable outcomes compared to ACDF for treatment of symptomatic cervical 2-level degenerative disc disease (DDD) indicating a satisfactory safety and efficacy profile.

Surgical treatment of early-onset idiopathic scoliosis in the United States: a trend analysis of 15 years (1997-2012).

BACKGROUND CONTEXT: Early-onset scoliosis is a challenging problem that is defined as a curvature of the spine of more than 10 degrees identified in a child less than 10 years. Early-onset idiopathic scoliosis (EOIS) can cause substantial morbidity and may require surgical intervention. PURPOSE: The aim of the present study was to identify the trends of EOIS type of surgeries, length of hospital stay, in-hospital complications, and total inpatient admission charges over a 15-year study period in the United States from 1997 to 2012. STUDY DESIGN/SETTING: This retrospective study used the ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) codes from the Healthcare Cost and Utilization Project (HCUP) Kids Inpatient's Database (KID) for a 15-year period (1997-2012). PATIENT SAMPLE: We identified a total of 897 patients with EOIS over the 15-year study period. OUTCOME MEASURES: The present study determines the current trends for EOIS surgeries. METHODS: The present study had no funding sources or any potential conflicts of interest associated biases. Idiopathic scoliosis patients with ages between 0 and <10 years were identified from the Kids' Inpatient Database with ICD-9-CM code 737.30. Posterior, anterior, and combined spinal surgeries were identified in EOIS through the procedure codes. Patients' gender, discharge diagnosis (comorbidities), hospital length of stay (LOS), mortality rates, hospital charges, and in-hospital complication rate data were collected between 1997 and 2012. The primary grouping variable of the study was the type of surgery (posterior, anterior, and combined). The trends of each variable (female gender, mortality rates, in-hospital complications rates, discharge diagnosis, LOS, and total hospital charges) were assessed for each surgical group separately. Cost inflation of hospital charges was adjusted for the year 2012. An analysis of variance test was used to analyze continuous variables and a chi-square test was used for categorical variables. A linear regression test was used to assess the trend of changes. p≤.05 was considered statistically significant. RESULTS: The study identified 897 patients, with 546 (61%) of them requiring surgery. Spine deformity surgery rates significantly decreased in patients with EOIS over time from 75% in 1997 to 47% in 2012, p=.019. In the surgery cohort, the male to female distribution was 37% and 63%, respectively. The overall mortality rate was 0.1%. The average length of hospital stay was 8 days and the average number of discharge diagnosis was 5.3. Aggregated complications were seen in 6% of the patients. The total mean hospital charge (per 2012 US dollars) was $119,613, which increased significantly for all types of surgeries. Over the 15-year study period, 62% (n=342) of the patients had posterior surgeries, 13% (n=71) of the patients had anterior surgeries, and 24% (n=133) of the patients had combined (anterior and posterior) surgeries. Posterior surgeries increased significantly from 33% in 1997 to 91% in 2012 (p<.004). Combined surgeries saw a significant decline from 50% to 4.3% (0<0.001). Anterior surgeries also decreased from 17% to 4.3% (p<.126), but this did not reach statistical significance. CONCLUSIONS: From 1997 to 2012 (15 years) study period of patients with EOIS, posterior-based surgeries significantly increased. The overall surgery rate has significantly decreased for these patients. A significant increase in hospital charges were noticed in posterior, anterior, and combined surgeries.

Assessment of Inter- and Intraobserver Reliability and Accuracy to Evaluate Apical Vertebral Rotation Using Four Methods: An Experimental Study Using a Saw Bone Model.

STUDY DESIGN: After placing a thoracic three-vertebra segment saw bones model on a standardized turntable, a series of anteroposterior (AP) radiographs were obtained and then set in increments to 90° rotation. Then the specimen was instrumented with 35-mm pedicle screws bilaterally and the rotation process and image acquisition were repeated. OBJECTIVE: Assess reliability and accuracy of spine surgeons evaluating apical vertebral rotation (AVR) through surgeon's visual x-ray estimation, Nash-Moe system, Upasani trigonometric method, and Upasani grading system. BACKGROUND CONTEXT: Accurate assessment of AVR is one measure surgeons can evaluate the success of intervention and potential loss of correction in scoliotic deformities. METHODS: Eighty-four representative images of uninstrumented and instrumented vertebral segments were blinded. AVR was estimated by five experienced spinal deformity surgeons using the four techniques. The surgeons' grading, estimates, and errors compared to actual rotation were calculated. Inter- and intraobserver reliability were calculated using interclass correlation (ICC). RESULTS: Each surgeon's error for simple visual estimation for uninstrumented segments was 8.7° to 17.4° (average error = 12.4°), and for instrumented segments it was 7.7° to 11.3° (average error = 9.5°). Error for the Upasani trigonometric method was -6.7° to 11.6° (average error = 0.9°). There was relatively poor accuracy for Nash-Moe system (38.2%-53.9%) compared with the Upasani grading system (76.74%-80.23%). Interobserver reliability using the Nash-Moe method was good (0.844), with intraobserver reliability from fair to excellent (0.684-0.949). Interobserver reliability for the Upasani grading method was good (0.829), with intraobserver reliability from fair to good (0.751-0.869). We found excellent interobserver reliability for Upasani trigonometric classification (0.935) with fair to excellent intraobserver reliability (0.775-0.991). The interobserver reliability of surgeons' visual estimates was good (0.898) and the intraobserver reliability from good to excellent (0.866-0.99) without pedicle screws, and interobserver reliability was excellent (0.948) and intraobserver reliability also excellent (0.959-0.986) with pedicle screws. CONCLUSIONS: We confirm that both techniques described by Upasani have good reliability and accuracy, appearing more accurate than surgeon's visual estimates or Nash-Moe system. LEVEL OF EVIDENCE: Level III.

Assessment of Coronal Spinal Alignment for Adult Spine Deformity Cases After Intraoperative T Square Shaped Use.

STUDY DESIGN: Retrospectively reviewed surgeries between 2011 and 2015 of patients who underwent posterior spinal deformity instrumentation with constructs involving fusions to pelvis and encompassing at least five levels. OBJECTIVE: Measure the radiographic outcomes of coronal malalignment (CM) after use of an intraoperative T square shaped instrument in posterior spinal deformity surgeries with at least five levels of fusion and extension to pelvis. BACKGROUND: Neuromuscular children found to benefit from intraoperative T square technique to help achieve proper coronal spinal balance with extensive fusions. This intraoperative technique used in our posterior spine deformity instrumentation surgeries with the aforementioned parameters. METHODS: There were 50 patients: n = 16 with intraoperative T square and n = 34 no-T square shaped device. Subgroups divided based on greater than 20 mm displacement and greater than 40 mm displacement of the C7 plumb line to the central sacral vertical line on either side in preoperative radiographs. We analyzed the demographics and the pre- and postoperative radiographic parameters of standing films: standing CM (displacement of C7 plumb line to central sacral vertical line), and major coronal Cobb angles in total sample and subgroups and compared T square shaped device with no-T square shaped device use by analysis of variance. A p value ≤.05 is statistically significant. RESULTS: In the total sample, though postoperative CM mean was not statistically different, we observed greater CM corrections in patients where a T square shaped device was used (70%) versus no-T square shaped device used (18%). In >20 mm and >40 mm subgroups, the postoperative mean CM values were statistically lower for the patients where a T square shaped device was used, p = .016 and p = .003, respectively. Cobb corrections were statistically higher for T square shaped device use in both >20 mm and >40 mm subgroups, 68%, respectively. CONCLUSION: The intraoperative T square shaped device technique had a positive effect on the amount of spine coronal malalignment correction after its use and for lumbar and thoracic coronal Cobb angles. LEVEL OF EVIDENCE: Level III.

Magnetically controlled growing rods for scoliosis surgery.

INTRODUCTION: Early onset scoliosis can be both a disfiguring as well as a life threatening condition. When more conservative treatments fail, pediatric spinal surgeons are forced to consider operative interventions. Traditionally, these interventions have involved the insertion of a variety of implants into the patient with a limited number of anchor points controlling the spine. In the past, these pediatric patients have had multiple surgeries for elective lengthening of these devices to facilitate their growth while attempting to control the scoliosis. These patients often experience a physical and emotional toll from their multiple repeated surgeries. Growing spine techniques have also had a noted high complication rate due to implant dislodgement and infections. Recently, the development of non-invasively, self-lengthening growing rods has occurred. These devices have the potential to allow for the devices to be lengthened magnetically in a conscious patient in the surgeon's office. Areas covered: This review summarized previously published articles in the English literature using a key word search in PubMed for: 'magnetically controlled growing rods', 'Magec rods', 'magnetic growing rods' and 'growing rods'. Expert commentary: Magnetically controlled growing rods have an advantage over growing rods in lengthening the growing spine in the absence of repetitive surgeries.