Single- versus dual-attending strategy for spinal deformity surgery: 2-year experience and systematic review of the literature.

OBJECTIVE: Adult spinal deformity (ASD) surgery is complex and associated with high morbidity and complication rates. There is growing evidence in the literature for the beneficial effects of an approach to surgery in which two attending physicians rather than a single attending physician perform surgery for and oversee the surgical care of a single patient in a dual-attending care model. The authors developed a dual-attending care collaboration in August 2017 in which a neurosurgeon and an orthopedic surgeon mutually operated on patients with ASD. METHODS: The authors recorded data for 2 years of experience with ASD patients operated on by dual attending surgeons. Analyses included estimated blood loss (EBL), transfusions, length of stay (LOS), discharge disposition, complication rates, emergency room visits and readmissions, subjective health status improvement, and disability (Oswestry Disability Index [ODI] score) and pain (visual analog scale [VAS] score) at last follow-up. In addition, the pertinent literature for dual-attending spinal deformity correction was systematically reviewed. RESULTS: The study group comprised 19 of 254 (7.5%) consecutively operated patients who underwent thoracolumbar fusion during the period from January 2017 to June 2019 (68.4% female; mean patient age 65.1 years, ODI score 44.5, VAS pain score 6.8). The study patients were matched by age, sex, anesthesia risk, BMI, smoking status, ODI score, VAS pain score, prior spine surgeries, and basic operative characteristics (type of interbody implants, instrumented segments, pelvic fixation) to 19 control patients (all p > 0.05). There was a trend toward less EBL (mean 763 vs 1524 ml, p = 0.059), fewer intraoperative red blood cell transfusions (mean 0.5 vs 2.3, p = 0.079), and fewer 90-day readmissions (0% vs 15.8%, p = 0.071) in the dual-attending group. LOS and discharge disposition were similar, as were the rates of any < 30-day postsurgery complications, < 90-day postsurgery emergency room visits, and reoperations, and ODI and VAS pain scores at last follow-up (all p > 0.05). At last follow-up, 94.7% vs 68.4% of patients in the dual- versus single-attending group stated their health status had improved (p = 0.036). In the authors' literature search of prior articles on spinal deformity correction, 5 of 8 (62.5%) articles reported lower EBL and 6 of 8 (75%) articles reported significantly lower operation duration in dual-attending cases. The literature contained differing results with regard to complication- or reoperation-sparing effects associated with dual-attending cases. Similar clinical outcomes of dual- versus single-attending cases were reported. CONCLUSIONS: Establishing a dual-attending care management platform for ASD correction was feasible at the authors' institution. Results of the use of a dual-attending strategy at the authors' institution were favorable. Positive safety and outcome profiles were found in articles on this topic identified by a systematic literature review.

Impact of lowest instrumented vertebra tilt and rotation on uninstrumented lumbar curve and L4 tilt in thoracic adolescent idiopathic scoliosis.

OBJECTIVE: Controversy exists regarding the effects of lowest instrumented vertebra (LIV) tilt and rotation on uninstrumented lumbar segments in adolescent idiopathic scoliosis (AIS) surgery. Because the intraoperative LIV tilt from the inferior endplate of the LIV to the superior sacral endplate is not stable after surgery, the authors measured the LIV angle of the instrumented thoracic spine as the LIV angle of the construct. This study aimed to evaluate the effects of the LIV angle of the construct and the effects of LIV rotation on the postoperative uninstrumented lumbar curve and L4 tilt in patients with thoracic AIS. METHODS: A retrospective correlation and multivariate analysis of a prospectively collected, consecutive, nonrandomized series of patients at a single institution was undertaken. Eighty consecutive patients with Lenke type 1 or type 2 AIS treated with posterior correction and fusion were included. Preoperative and 2-year postoperative radiographic measurements were the outcome measures for this study. Outcome variables were postoperative uninstrumented lumbar segments (LIV tilt, LIV translation, uninstrumented lumbar curve, thoracolumbar/lumbar [TL/L] apical vertebral translation [AVT], and L4 tilt). The LIV angle of the construct was measured from the orthogonal line drawn from the upper instrumented vertebra to the LIV. Multiple stepwise linear regression analysis was conducted between outcome variables and patient demographics/radiographic measurements. There were no study-specific biases related to conflicts of interest. RESULTS: Predictor variables for postoperative uninstrumented lumbar curve were the postoperative LIV angle of the construct, number of uninstrumented lumbar segments, and flexibility of TL/L curve. Specifically, a lower postoperative uninstrumented lumbar curve was predicted by a lower absolute value of the postoperative LIV angle of the construct (p < 0.0001). Predictor variables for postoperative L4 tilt were postoperative LIV rotation, preoperative L4 tilt, and preoperative uninstrumented lumbar curve. Specifically, a lower postoperative L4 tilt was predicted by a lower absolute value of postoperative LIV rotation (p < 0.0001). CONCLUSIONS: The LIV angle of the construct significantly affected the LIV tilt, uninstrumented lumbar curve, and TL/L AVT. LIV rotation significantly affected the LIV translation and L4 tilt.

Efficacy of intraoperative cell salvage in spine surgery: a meta-analysis.

OBJECTIVE: Intraoperative cell salvage systems, or cell savers, are widely used for the management of blood loss in patients undergoing spine surgery. However, recent studies report conflicting evidence of their efficacy. The purpose of the meta-analysis was to investigate the efficacy of cell savers in reducing blood transfusion requirements in patients undergoing spine surgery. METHODS: Both retrospective and prospective studies that investigated the efficacy of cell savers in reducing transfusion requirements in spine surgery patients when compared with control patients were identified from MEDLINE, Embase, Cochrane Collaboration Library, Google Scholar, and Scopus databases. Outcome data extracted included number of patients receiving allogenic transfusions (transfusion rate); units of allogenic transfusions; postoperative hemoglobin; costs; operative time; and complications. RevMan 5 software was used to perform statistical analyses. A random-effects model was used to calculate pooled odds ratios (with 95% CIs) and weighted mean differences (WMDs [95% CI]) for dichotomous and continuous variables, respectively. RESULTS: Eighteen studies with 2815 patients in total were included in the meta-analysis. During spine surgery, the use of intraoperative cell salvage did not reduce the intraoperative (OR 0.66 [95% CI 0.30, 1.41]), postoperative (OR -0.57 [95% CI 0.20, 1.59]), or total transfusion (OR 0.92 [95% CI 0.43, 1.98]) rate. There was a reduction in the number of allogenic units transfused intraoperatively by a mean of 0.81 (95% CI -1.15, -0.48). However, there were no differences in the number of units transfused postoperatively (WMD -0.02 [95% CI -0.41, 0.38]) or the total units transfused (WMD 0.08 [95% CI -1.06, 1.22]). There were also no differences in operative time (WMD 19.36 [95% CI -2.43, 42.15]) or complications reported (OR 0.79 [95% CI 0.46, 1.37]) between groups. A difference in postoperative hemoglobin (WMD 0.54 [95% CI 0.11, 0.98]) between both groups was observed. CONCLUSIONS: Cell saver is efficacious at reducing intraoperative allogenic units transfused. There is no difference in transfusion rates, postoperative units transfused, and the total number of units transfused. Further cost analysis studies are necessary to evaluate the cost-effectiveness of this method of blood conservation.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: meta-analysis; strength of recommendation: low.

Surgical management of moderate adolescent idiopathic scoliosis with a fusionless posterior dynamic deformity correction device: interim results with bridging 5-6 disc levels at 2 or more years of follow-up.

OBJECTIVE: A posterior dynamic deformity correction (PDDC) system was used to correct adolescent idiopathic scoliosis (AIS) without fusion. The preliminary outcomes of bridging only 3-4 discs in patients with variable curve severity have previously been reported. This paper examines a subgroup of patients with the authors' proposed current indications for this device who were also treated with a longer construct. METHODS: Inclusion criteria included a single AIS structural curve between 40° and 60°, curve flexibility ≤ 30°, PDDC spanning 5-6 levels, and minimum 2-year follow-up. A retrospective review was conducted and demographic and radiographic data were recorded. A successful outcome was defined as a curve magnitude of ≤ 30° at final follow-up. Any serious adverse events and reoperations were recorded. RESULTS: Twenty-two patients who met the inclusion criteria were operated on with the PDDC in 5 medical centers. There were 19 girls and 3 boys, aged 13-17 years, with Risser grades ≥ 2. Thirteen had Lenke type 1 curves and 9 had type 5 curves. The mean preoperative curve was 47° (range 40°-55°). At a minimum of 2 years' follow-up, the mean major curve measured 25° (46% correction, p < 0.05). In 18 (82%) of 22 patients, the mean final Cobb angle measured ≤ 30° (range 15°-30°). Trunk shift was corrected by 1.5 cm (range 0.4-4.3 cm). The mean minor curve was reduced from 27° to 17° at final follow-up (35% correction, p < 0.05). For Lenke type 1 patterns, the mean 2D thoracic kyphosis was 24° preoperatively versus 27° at final follow-up (p < 0.05), and for Lenke type 5 curves, mean lumbar lordosis was 47° preoperatively versus 42° at final follow-up (p < 0.05). The mean preoperative Scoliosis Research Society-22 questionnaire score improved from 2.74 ± 0.3 at baseline to 4.31 ± 0.4 at 2 years after surgery (p < 0.0001). The mean preoperative self-image score and satisfaction scores improved from preoperative values, while other domain scores did not change significantly. Four patients (18%) underwent revision surgery because of nut loosening (n = 2), pedicle screw backup (n = 1), and ratchet malfunction (n = 1). CONCLUSIONS: In AIS patients with a single flexible major curve up to 60°, the fusionless PDDC device achieved a satisfactory result as 82% had residual curves ≤ 30°. These findings suggest that the PDDC device may serve as an alternative to spinal fusion in select patients.

The effect of hospital characteristics on pediatric neuromuscular scoliosis fusion cost.

OBJECTIVE: Spinal fusion is used in the treatment of pediatric neuromuscular scoliosis (NMS) to improve spine alignment and delay disease progression. However, patients with NMS are often medically complex and require a higher level of care than those with other types of scoliosis, leading to higher treatment costs. The purpose of this study was to 1) characterize the cost of pediatric NMS fusion in the US and 2) determine hospital characteristics associated with changes in overall cost. METHODS: Patients were identified from the National Inpatient Sample (2012 to the first 3 quarters of 2015). Inclusion criteria selected for patients with NMS, spinal fusion of at least 4 vertebral levels, and elective hospitalization. Patients with no cost information were excluded. Sociodemographics, treating hospital characteristics, disease etiology/severity, comorbidities, length of stay, and hospital costs were collected. Univariable analysis and multivariable gamma log-link regression were used to determine hospital characteristics associated with changes in cost. RESULTS: A total of 1780 weighted patients met inclusion criteria. The median cost was $68,815. Following multivariable regression, both small (+$11,580, p < 0.001) and medium (+$6329, p < 0.001) hospitals had higher costs than large hospitals. Rural hospitals had higher costs than urban teaching hospitals (+$32,438, p < 0.001). Nonprofit hospitals were more expensive than both government (-$4518, p = 0.030) and investor-owned (-$10,240, p = 0.001) hospitals. There was significant variability by US census division; compared with the South Atlantic, all other divisions except for the Middle Atlantic had significantly higher costs, most notably the West North Central (+$15,203, p < 0.001) and the Pacific (+$22,235, p < 0.001). Hospital fusion volume was not associated with total cost. CONCLUSIONS: A number of hospital factors were associated with changes in fusion cost. Larger hospitals may be able to achieve decreased costs due to economies of scale. Regional differences could reflect uncontrolled-for variability in underlying patient populations or systems-level and policy differences. Overall, this analysis identified multiple systemic patterns that could be targets of further cost-related interventions.

Pediatric thoracolumbar spine surgery and return to athletics: a systematic review.

OBJECTIVE: Spinal conditions and injuries in the pediatric population can necessitate surgical treatment. For many pediatric patients, a return to athletic activity after spinal surgery is a significant postoperative focus. However, there is a lack of standardized guidelines to determine criteria for safe return to play (RTP). To understand clinical criteria for patients to safely RTP, the authors conducted a systematic review of outcomes and the period of time before physicians recommend an RTP for pediatric patients undergoing spinal surgery. METHODS: English-language publications were searched systematically in the PubMed electronic database, and a review was conducted in accordance with the PRISMA guidelines. Additional relevant studies found via a supplementary literature search were also included. Studies assessing return to athletic activity in a pediatric population after spinal surgery were included. Studies without an RTP, postsurgical activity outcomes, or surgical intervention were excluded. RESULTS: A PubMed search identified 295 articles, with 29 included for the systematic review. In addition, 4 studies were included from a supplementary literature search. The majority of these studies were retrospective case series and cohort studies, and the remaining studies included questionnaire-based studies, prospective cohorts, and case-control studies. The most common spinal conditions or injuries included spondylolysis, and this was followed by adolescent idiopathic scoliosis. Overall, the most frequent recommendation for RTP for noncontact and contact sports was 6 months after surgery (range 1-12 months), and for collision sports it was 12 months after surgery. However, some physicians recommended never returning to collision sports after spinal intervention. CONCLUSIONS: Most pediatric patients are able to return to some level of sports after spinal surgery. However, no standardized criteria have been proposed, and RTP recommendations vary according to the treating surgeon. In addition, limited data are published on the variation in timelines for RTP with regard to classifications of sports (noncontact, contact, and collision). Further analysis of specific spinal conditions and injuries with postoperative athletic recovery is needed.

Reduced influence of affective disorders on perioperative complication rates, length of hospital stay, and healthcare costs following spinal fusion for adolescent idiopathic scoliosis.

OBJECTIVE: In the past decade, a gradual transition of health policy to value-based healthcare has brought increased attention to measuring the quality of care delivered. In spine surgery, adolescents with scoliosis are a population particularly at risk for depression, anxious feelings, and impaired quality of life related to back pain and cosmetic appearance of the deformity. With the rising prevalence of mental health ailments, it is necessary to evaluate the impact of concurrent affective disorders on patient care after spinal surgery in adolescents. The aim of this study was to investigate the impact that affective disorders have on perioperative complication rates, length of stay (LOS), and total costs in adolescents undergoing elective posterior spinal fusion (PSF) (≥ 4 levels) for idiopathic scoliosis. METHODS: A retrospective study of the Kids' Inpatient Database for the year 2012 was performed. Adolescent patients (age range 10-17 years old) with AIS undergoing elective PSF (≥ 4 levels) were selected using the International Classification of Diseases, Ninth Revision, Clinical Modification coding system. Patients were categorized into 2 groups at discharge: affective disorder or no affective disorder. Patient demographics, comorbidities, complications, LOS, discharge disposition, and total cost were assessed. The primary outcomes were perioperative complication rates, LOS, total cost, and discharge dispositions. RESULTS: There were 3759 adolescents included in this study, of whom 164 (4.4%) were identified with an affective disorder (no affective disorder: n = 3595). Adolescents with affective disorders were significantly older than adolescents with no affective disorders (affective disorder: 14.4 ± 1.9 years vs no affective disorder: 13.9 ± 1.8 years, p = 0.001), and had significantly different proportions of race (p = 0.005). Aside from hospital region (p = 0.016), no other patient- or hospital-level factors differed between the cohorts. Patient comorbidities did not differ significantly between cohorts. The number of vertebral levels involved was similar between the cohorts, with the majority of patients having 9 or more levels involved (affective disorder: 76.8% vs no affective disorder: 79.5%, p = 0.403). Postoperative complications were similar between the cohorts, with no significant difference in the proportion of patients experiencing a postoperative complication (p = 0.079) or number of complications (p = 0.124). The mean length of stay and mean total cost were similar between the cohorts. Moreover, the routine and nonroutine discharge dispositions were also similar between the cohorts, with the majority of patients having routine discharges (affective disorder: 93.9% vs no affective disorder: 94.9%, p = 0.591). CONCLUSIONS: This study suggests that affective disorders may not have a significant impact on surgical outcomes in adolescent patients undergoing surgery for scoliosis in comparison with adults. Further studies are necessary to elucidate how affective disorders affect adolescent patients with idiopathic scoliosis, which may improve provider approach in managing these patients perioperatively and at follow-up in hopes to better the overall patient satisfaction and quality of care delivered.

Impact of patient and hospital-level risk factors on extended length of stay following spinal fusion for adolescent idiopathic scoliosis.

OBJECTIVE: Health policy changes have led to increased emphasis on value-based care to improve resource utilization and reduce inpatient hospital length of stay (LOS). Recently, LOS has become a major determinant of quality of care and resource utilization. For adolescent idiopathic scoliosis (AIS), the determinants of extended LOS after elective posterior spinal fusion (PSF) remain relatively unknown. In the present study, the authors investigated the impact of patient and hospital-level risk factors on extended LOS following elective PSF surgery (≥ 4 levels) for AIS. METHODS: The Kids' Inpatient Database (KID) was queried for the year 2012. Adolescent patients (age range 10-17 years) with AIS undergoing elective PSF (≥ 4 levels) were selected using the International Classification of Diseases, Ninth Revision, Clinical Modification coding system. Extended hospital LOS was defined as greater than the 75th percentile for the entire cohort (> 6 days), and patients were dichotomized as having normal LOS or extended LOS. Patient demographics, comorbidities, complications, LOS, discharge disposition, and total cost were recorded. A multivariate logistic regression model was used to determine the odds ratio for risk-adjusted LOS. The primary outcome was the degree to which patient comorbidities or postoperative complications correlated with extended LOS. RESULTS: Comorbidities were overall significantly higher in the extended-LOS cohort than the normal-LOS cohort. Patients with extended LOS had a significantly greater proportion of blood transfusion (p < 0.001) and ≥ 9 vertebral levels fused (p < 0.001). The overall complication rates were greater in the extended-LOS cohort (20.3% [normal-LOS group] vs 43.5% [extended-LOS group]; p < 0.001). On average, the extended-LOS cohort incurred $18,916 more in total cost than the normal-LOS group ($54,697 ± $24,217 vs $73,613 ± $38,689, respectively; p < 0.001) and had more patients discharged to locations other than home (p < 0.001) than did patients in the normal-LOS cohort. On multivariate logistic regression, several risk factors were associated with extended LOS, including female sex, obesity, hypertension, fluid electrolyte disorder, paralysis, blood transfusion, ≥ 9 vertebrae fused, dural injury, and nerve cord injury. The odds ratio for extended LOS was 1.95 (95% CI 1.50-2.52) for patients with 1 complication and 5.43 (95% CI 3.35-8.71) for patients with > 1 complication. CONCLUSIONS: The authors' study using the KID demonstrates that patient comorbidities and intra- and postoperative complications all contribute to extended LOS after spinal fusion for AIS. Identifying multimodality interventions focused on reducing LOS, bettering patient outcomes, and lowering healthcare costs are necessary to improve the overall value of care for patients undergoing spinal fusion for AIS.

Upper instrumented vertebra to the right of the lowest instrumented vertebra as a predictor of an increase in the main thoracic curve after selective posterior fusion for the thoracolumbar/lumbar curve in Lenke type 5C adolescent idiopathic scoliosis: multicenter study on the relationship between fusion area and surgical outcome.

OBJECTIVE: Unfused main thoracic (MT) curvatures occasionally increase after selective thoracolumbar/lumbar (TL/L) fusion. This study sought to identify the predictors of an unacceptable increase in MT curve (UIMT) after selective posterior fusion (SPF) of the TL/L curve in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS). METHODS: Forty-eight consecutive patients (44 females and 4 males, mean age 15.7 ± 2.5 years, range 13-24 years) with Lenke type 5C AIS who underwent SPF of the TL/L curve were analyzed. The novel "Shinshu line" (S-line) was defined as a line connecting the centers of the concave-side pedicles of the upper instrumented vertebra (UIV) and lowest instrumented vertebra (LIV) on preoperative radiographs. The authors established an S-line tilt to the right as S-line positive (S-line+, i.e., the UIV being to the right of the LIV) and compared S-line+ and S-line- groups for thoracic apical vertebral translation (T-AVT) and MT Cobb angle preoperatively, early postoperatively, and at final follow-up. The predictors for T-AVT > 20 mm at final follow-up were evaluated as well. T-AVT > 20 mm was defined as a UIMT. RESULTS: Among the 48 consecutively treated patients, 26 were S-line+ and 22 were S-line-. At preoperative, early postoperative, and final follow-up a minimum of 2 years later, the mean T-AVT was 12.8 mm (range -9.3 to 32.8 mm), 19.6 mm (range -13.0 to 41.0 mm), and 22.8 mm (range -1.9 to 68.7 mm) in the S-line+ group, and 10.8 mm (range -5.1 to 27.3 mm), 16.2 mm (range -11.7 to 42.1 mm), and 11.0 mm (range -6.3 to 26.9 mm) in the S-line- group, respectively. T-AVT in S-line+ patients was significantly larger than that in S-line- patients at the final follow-up. Multivariate analysis revealed S-line+ (odds ratio [OR] 23.8, p = 0.003) and preoperative MT Cobb angle (OR 7.9, p = 0.001) to be predictors of a UIMT. CONCLUSIONS: S-line+ was defined as the UIV being to the right of the LIV. T-AVT in the S-line+ group was significantly larger than in the S-line- group at the final follow-up. S-line+ status and larger preoperative MT Cobb angle were independent predictors of a UIMT after SPF for the TL/L curve in patients with Lenke type 5C AIS. Surgeons should consider changing the UIV and/or LIV in patients exhibiting S-line+ during preoperative planning to avoid a possible increase in MT curve and revision surgery.

Is the apical vertebra the most rotated vertebra in the scoliotic curve?

OBJECTIVE: The aim of this study was to determine if the apical vertebra (AV) in patients with adolescent idiopathic scoliosis (AIS) is the most rotated vertebra in the scoliotic segment. METHODS: A total of 158 patients with AIS (Cobb angle range 20°-101°) underwent biplanar radiography with 3D reconstructions of the spine and calculation of vertebral axial rotations. The type of major curvature was recorded (thoracic, thoracolumbar, or lumbar), and both major and minor curvatures were included. The difference of levels (DL) between the level of maximal vertebral rotation (LMVR) and the AV was calculated as follows: DL = 0 if LMVR and AV were the same, DL = 1 if LMVR was directly above or below the AV, and DL = 2 if LMVR was separated by 1 vertebra or more from the AV. To investigate which factors explained the divergence of the LMVR from the AV, multinomial models were computed. RESULTS: The distribution of the DL was as follows: for major curvatures, 143 were DL = 0, 11 were DL = 1, and 4 were DL = 2; and for minor curvatures, 53 were DL = 0, 9 were DL = 1, and 31 were DL = 2. The determinants of a DL = 2 (compared with DL = 0) were lumbar curvature (compared with thoracic; adjusted OR 0.094, p = 0.001), major curvature (compared with minor; adjusted OR 0.116, p = 0.001), and curvatures with increasing apical vertebral rotation (adjusted OR 0.788, p < 0.001). CONCLUSIONS: This study showed that the AV is the most rotated vertebra in the majority of major curvatures, while in minor curvatures, the most rotated vertebra appears to be the junctional vertebra between major and minor curvatures in a significant proportion of cases.

Radiological and clinical predictors of scoliosis in patients with Chiari malformation type I and spinal cord syrinx from the Park-Reeves Syringomyelia Research Consortium.

OBJECTIVE: Scoliosis is frequently a presenting sign of Chiari malformation type I (CM-I) with syrinx. The authors' goal was to define scoliosis in this population and describe how radiological characteristics of CM-I and syrinx relate to the presence and severity of scoliosis. METHODS: A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°). RESULTS: Based on available imaging of patients with CM-I and syrinx, 260 of 825 patients (31%) had a clear diagnosis of scoliosis based on radiographs or coronal MRI. Forty-nine patients (5.9%) did not have scoliosis, and in 516 (63%) patients, a clear determination of the presence or absence of scoliosis could not be made. Comparison of patients with and those without a definite scoliosis diagnosis indicated that scoliosis was associated with wider syrinxes (8.7 vs 6.3 mm, OR 1.25, p < 0.001), longer syrinxes (10.3 vs 6.2 levels, OR 1.18, p < 0.001), syrinxes with their rostral extent located in the cervical spine (94% vs 80%, OR 3.91, p = 0.001), and holocord syrinxes (50% vs 16%, OR 5.61, p < 0.001). Multivariable regression analysis revealed syrinx length and the presence of holocord syrinx to be independent predictors of scoliosis in this patient cohort. Scoliosis was not associated with sex, age at CM-I diagnosis, tonsil position, pB-C2 distance (measured perpendicular distance from the ventral dura to a line drawn from the basion to the posterior-inferior aspect of C2), clivoaxial angle, or frontal-occipital horn ratio. Average curve magnitude was 29.9°, and 37.7% of patients had a left thoracic curve. Older age at CM-I or syrinx diagnosis (p < 0.0001) was associated with greater curve magnitude whereas there was no association between syrinx dimensions and curve magnitude. CONCLUSIONS: Syrinx characteristics, but not tonsil position, were related to the presence of scoliosis in patients with CM-I, and there was an independent association of syrinx length and holocord syrinx with scoliosis. Further study is needed to evaluate the nature of the relationship between syrinx and scoliosis in patients with CM-I.

Enhanced recovery after spine surgery: a systematic review.

OBJECTIVEEnhanced recovery after surgery (ERAS) is a multidimensional approach to improving the care of surgical patients using subspecialty- and procedure-specific evidence-based protocols. The literature provides evidence of the benefits of ERAS implementation, which include expedited functional recovery, decreased postoperative morbidity, reduced costs, and improved subjective patient experience. Although extensively examined in other surgical areas, ERAS principles have been applied to spine surgery only in recent years. The authors examine studies investigating the application of ERAS programs to patients undergoing spine surgery.METHODSThe authors conducted a systematic review of the PubMed and MEDLINE databases up to November 20, 2018.RESULTSTwenty full-text articles were included in the qualitative analysis. The majority of studies were retrospective reviews of nonrandomized data sets or qualitative investigations lacking formal control groups; there was 1 protocol for a future randomized controlled trial. Most studies demonstrated reduced lengths of stay and no increase in rates of readmissions or complications after introduction of an ERAS pathway.CONCLUSIONSThese introductory studies demonstrate the potential of ERAS protocols, when applied to spine procedures, to reduce lengths of stay, accelerate return of function, minimize postoperative pain, and save costs.

Case-matched comparative analysis of spinal deformity correction in arthrogryposis multiplex congenita versus adolescent idiopathic scoliosis.

OBJECTIVEAs scoliosis in arthrogryposis multiplex congenita (AMC) is unusual and the number of cases reviewed in previous studies is also relatively small, no previous study exists that has directly compared the results of spinal deformity correction between AMC and adolescent idiopathic scoliosis (AIS) patients. The aim of this study was to compare the radiographic and clinical outcomes of surgical correction of spinal deformity associated with AMC versus AIS.METHODSTwenty-four adolescents with AMC were matched with 48 AIS patients in terms of Cobb angle of main curve, curve pattern, sex, age at surgery, Risser grade, and length of follow-up. Patients in both groups underwent posterior-only spinal correction and fusion procedures. The surgical outcomes and complications were analyzed and compared between the 2 groups.RESULTSIn comparison to the AIS group, the AMC group had a significantly longer mean operation time (5.6 vs 4.4 hours, p = 0.002), more blood loss (1620 ± 250 ml vs 840 ± 260 ml, p < 0.001), and more fusion levels (14.1 ± 2.3 levels vs 12.4 ± 2.5 levels, p = 0.007) as well as a lower correction rate (44.3% ± 11.1% vs 70.8% ± 12.4%, p < 0.001) and a higher rate of loss of correction (5.0% ± 3.1% vs 2.1% ± 1.9%, p < 0.001). Nine patients in the AMC group had preoperative pelvic obliquity, which was corrected from a mean of 14.2° ± 8.4° to a mean of 4.3° ± 3.2° (p < 0.001) after the surgery. The thoracic lordosis and sagittal vertical axis were significantly improved in the AMC group. Notably, however, the AMC group was found to have higher rates of screw malpositioning (15.9% vs 9.5%, p = 0.002) and complications (8/24 [33.3%] vs 4/48 [8.3%], p = 0.016) as compared to the AIS group.CONCLUSIONSCorrection of AMC-associated scoliosis tends to require a longer operating time and involve more fusion levels but results in less correction, more blood loss, and more complications, in comparison with AIS. In addition, more attention should be paid to pelvic obliquity and sagittal hyperlordosis in AMC patients.

Postoperative translation of the upper instrumented vertebra in thoracic adolescent idiopathic scoliosis.

OBJECTIVEThe aim of this retrospective study was to analyze the influence of upper instrumented vertebra (UIV) translation from the C7 plumb line (C7PL) on the long-term postoperative results of patients with main thoracic (MT) adolescent idiopathic scoliosis (AIS).METHODSTwenty-five patients had been treated surgically for AIS with a Lenke type 1 curve and had been followed up for a mean period of 18.2 years. Radiographic parameters, pulmonary function measurements, and clinical outcomes were compared between the patients (n = 15) with UIV translation < 20 mm and those (n = 10) with UIV translation ≥ 20 mm at the final follow-up. Correlations between UIV translation and radiographic or pulmonary function parameters were analyzed.RESULTSPatients with ≥ 20 mm UIV translation at the final follow-up had a significantly larger preoperative UIV translation than that in the patients with < 20 mm UIV translation at follow-up. The former group also had a significantly lower correction rate of the MT curve, higher chest cage ratio, and lower radiographic shoulder height (p = 0.01, 0.005, and 0.025, respectively) at the final follow-up. The Scoliosis Research Society (SRS)-30 Questionnaire scores were equivalent between the two groups. Correlation analysis showed that the following parameters were significantly associated with UIV translation: MT curve correction rate (r = -0.481, p = 0.015), chest cage ratio (r = 0.673, p < 0.001), and percent-predicted forced expiratory volume in 1 second (r = -0.455, p = 0.033).CONCLUSIONSThe UIV translation should be considered an important factor that influences postoperative results. In MT AIS patients whose preoperative upper end vertebra (UEV) is distant from the C7PL, the UIV should be selected above the UEV to prevent large UIV translation at the postoperative follow-up.

Sagittal alignment of the cervical spine in the setting of adolescent idiopathic scoliosis.

OBJECTIVEThe goal of this study was to investigate the impact of thoracic and lumbar alignment on cervical alignment in patients with adolescent idiopathic scoliosis (AIS).METHODSEighty-one patients with AIS who had a Cobb angle > 40° and full-length spine radiographs were included. Radiographs were analyzed using dedicated software to measure pelvic parameters (sacral slope [SS], pelvic incidence [PI], pelvic tilt [PT]); regional parameters (C1 slope, C0-C2 angle, chin-brow vertical angle [CBVA], slope of line of sight [SLS], McRae slope, McGregor slope [MGS], C2-7 [cervical lordosis; CL], C2-7 sagittal vertical axis [SVA], C2-T3, C2-T3 SVA, C2-T1 Harrison measurement [C2-T1 Ha], T1 slope, thoracic kyphosis [TK], lumbar lordosis [LL], and PI-LL mismatch); and global parameters (SVA). Patients were stratified by their lumbar alignment into hyperlordotic (LL > 59.7°) and normolordotic (LL 39.3° to 59.7°) groups and also, based on their thoracic alignment, into hypokyphotic (TK < -33.1°) and normokyphotic (TK -33.1° to -54.9°) groups. Finally, they were grouped based on their global alignment into either an anterior-aligned group or a posterior-aligned group.RESULTSThe lumbar hyperlordotic group, in comparison to the normolordotic group, had a significantly larger LL, SS, PI (all p < 0.001), and TK (p = 0.014) and a significantly smaller PI-LL mismatch (p = 0.001). Lumbar lordosis had no influence on local cervical parameters.The thoracic hypokyphotic group had a significantly larger PI-LL mismatch (p < 0.002) and smaller T1 slope (p < 0.001), and was significantly more posteriorly aligned than the normokyphotic group (-15.02 ± 8.04 vs 13.54 ± 6.17 [mean ± SEM], p = 0.006). The patients with hypokyphotic AIS had a kyphotic cervical spine (cervical kyphosis [CK]) (p < 0.001). Furthermore, a posterior-aligned cervical spine in terms of C2-7 SVA (p < 0.006) and C2-T3 SVA (p < 0.001) was observed in the thoracic hypokyphotic group.Comparing patients in terms of global alignment, the posterior-aligned group had a significantly smaller T1 slope (p < 0.001), without any difference in terms of pelvic, lumbar, and thoracic parameters when compared to the anterior-aligned group. The posterior-aligned group also had a CK (-9.20 ± 1.91 vs 5.21 ± 2.95 [mean ± SEM], p < 0.001) and a more posterior-aligned cervical spine, as measured by C2-7 SVA (p = 0.003) and C2-T3 SVA (p < 0.001).CONCLUSIONSAlignment of the cervical spine is closely related to thoracic curvature and global alignment. In patients with AIS, a hypokyphotic thoracic alignment or posterior global alignment was associated with a global cervical kyphosis. Interestingly, upper cervical and cranial parameters were not statistically different in all investigated groups, meaning that the upper cervical spine was not recruited for compensation in order to maintain a horizontal gaze.

A new criterion for the alarm point using a combination of waveform amplitude and onset latency in Br(E)-MsEP monitoring in spine surgery.

OBJECTIVE: Monitoring of brain evoked muscle-action potentials (Br[E]-MsEPs) is a sensitive method that provides accurate periodic assessment of neurological status. However, occasionally this method gives a relatively high rate of false-positives, and thus hinders surgery. The alarm point is often defined based on a particular decrease in amplitude of a Br(E)-MsEP waveform, but waveform latency has not been widely examined. The purpose of this study was to evaluate onset latency in Br(E)-MsEP monitoring in spinal surgery and to examine the efficacy of an alarm point using a combination of amplitude and latency. METHODS: A single-center, retrospective study was performed in 83 patients who underwent spine surgery using intraoperative Br(E)-MsEP monitoring. A total of 1726 muscles in extremities were chosen for monitoring, and acceptable baseline Br(E)-MsEP responses were obtained from 1640 (95%). Onset latency was defined as the period from stimulation until the waveform was detected. Relationships of postoperative motor deficit with onset latency alone and in combination with a decrease in amplitude of ≥ 70% from baseline were examined. RESULTS: Nine of the 83 patients had postoperative motor deficits. The delay of onset latency compared to the control waveform differed significantly between patients with and without these deficits (1.09% ± 0.06% vs 1.31% ± 0.14%, p < 0.01). In ROC analysis, an intraoperative 15% delay in latency from baseline had a sensitivity of 78% and a specificity of 96% for prediction of postoperative motor deficit. In further ROC analysis, a combination of a decrease in amplitude of ≥ 70% and delay of onset latency of ≥ 10% from baseline had sensitivity of 100%, specificity of 93%, a false positive rate of 7%, a false negative rate of 0%, a positive predictive value of 64%, and a negative predictive value of 100% for this prediction. CONCLUSIONS: In spinal cord monitoring with intraoperative Br(E)-MsEP, an alarm point using a decrease in amplitude of ≥ 70% and delay in onset latency of ≥ 10% from baseline has high specificity that reduces false positive results.

Postoperative changes in sagittal spinopelvic alignment in sitting position in adolescents with idiopathic thoracic scoliosis treated with posterior fusion: an initial analysis.

OBJECTIVE Previous studies have reported spinal straightening and pelvic retroversion when changing from erect to sitting posture in patients with adolescent idiopathic scoliosis (AIS), which were thought to be related to low-back pain after sitting for long periods. However, the sitting sagittal alignment after posterior spinal fusion has not been evaluated. This study aims to assess the influence of posterior fusion surgery upon sitting sagittal spinopelvic alignment in adolescents with idiopathic thoracic curves (thoracic AIS [T-AIS]). METHODS A total of 44 T-AIS patients (30 Lenke I and 14 Lenke II) from the authors' center were included in this study. Preoperative and postoperative long-cassette lateral radiographs of the spine and pelvis were obtained with the patients in standing and sitting positions. Thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were measured on standing and sitting lateral radiographs. Patients were divided into selective thoracic fusion (STF) and nonselective thoracic fusion (NSTF) groups. RESULTS At baseline, TK, LL, and SS decreased by 27.5%, 42.1%, and 31.1%, respectively, from the standing to the sitting position, while PT increased by 193.6%. After posterior spinal fusion, increased TK, LL, and SS and corresponding decreased PT were observed compared to baseline parameters in the sitting position. Comparison of postoperative sitting and standing values for the whole cohort showed that the mean LS and SS values were significantly lower in the sitting position (decreased by 14.0% and 13.9%, respectively, compared to standing), whereas the mean PT value was significantly greater (increased by 39.0%, compared to standing). Similar changes were also observed in the STF group: postoperatively the mean LL value was 15.6% lower in sitting than in standing, while the mean SS value was 11.5% lower. However, no obvious changes of the postoperative values in sitting were found in the NSTF group. CONCLUSIONS Nonselective thoracic fusion surgery in T-AIS patients diminished spinal straightening and pelvic retroversion during sitting. Reducing distal fusion levels was of special value in not only saving more lumbar mobility, but also preserving the function of pelvic posterior rotation.

Risk factor analysis of proximal junctional kyphosis after posterior osteotomy in patients with ankylosing spondylitis.

OBJECTIVE The aim of this paper was to analyze the incidence and risk factors of proximal junctional kyphosis (PJK) in patients with ankylosing spondylitis (AS) who underwent pedicle subtraction osteotomy. METHODS The records of 83 patients with AS and thoracolumbar kyphosis who underwent surgery at the authors' institution between 2007 and 2013 were reviewed. The patients were divided into 2 groups based on the presence or absence of PJK. The radiographic measurements, including proximal junctional angle (PJA), sagittal parameters, and pelvic parameters of these 2 groups, were compared at different time points: before surgery and 2 weeks, 12 months, and 2 years after surgery. Oswestry Disability Index scores were also evaluated. RESULTS Overall, 14.5% of patients developed PJK. Before surgery, the mean PJAs in the 2 groups were 13.6° and 8.5°, respectively (p = 0.008). There were no significant differences in age, sex, and body mass index between groups. Patients with PJK had a larger thoracolumbar kyphotic angle (50.8° ± 12.6°) and a greater sagittal vertical axis (21.7 ± 4.3 cm) preoperatively than those without PJK. The proportion of patients with PJK whose fusion extended to the sacrum was 41.2% (7/17), which is significantly greater than the proportion of patients with PJK whose lowest instrumented vertebra was above the sacrum. Oswestry Disability Index scores did not significantly increase in the PJK group compared with the non-PJK group. CONCLUSIONS The authors found that PJK occurs postoperatively in patients with AS with an incidence of 14.5%. Risk factors of PJK include larger preoperative sagittal vertical axis, PJA, and osteotomy angle. Reducing the osteotomy angle in some severe cases and extending fusion to a higher, flatter level would be also beneficial in decreasing the risk of PJK.

Referral patterns and patient characteristics at the first visit to a scoliosis center: a 2-year experience in South Korea without a school scoliosis-screening program.

OBJECTIVE The need for scoliosis screening remains controversial. Nationwide school screening for scoliosis has not been performed in South Korea, and there are few studies on the referral patterns of patients suspected of having scoliosis. This study aimed to examine the referral patterns to the largest scoliosis center in South Korea in the absence of a school screening program and to analyze the factors that influence the appropriateness of referral. METHODS The medical records of patients who visited a single scoliosis center for a spinal deformity evaluation were reviewed. Among 1895 new patients who visited this scoliosis center between April 2014 and March 2016, 1211 with presumed adolescent idiopathic scoliosis were included in the study. Patients were classified into 4 groups according to the referral method: non-health care provider, primary physician, hospital specialist, or school screening program. The appropriateness of referral was labeled as inappropriate, late, or appropriate. In total, 213 of 1211 patients were excluded because they had received treatment at another medical facility; 998 patients were evaluated to determine the appropriateness of referral. RESULTS Of the 998 referrals of new patients with presumed adolescent idiopathic scoliosis, 162 (16.2%) were classified as an inappropriate referral, 272 (27.3%) were classified as a late referral, and 564 (56.5%) were classified as an appropriate referral. Age, sex, Cobb angle of the major curve, and skeletal maturity were identified as statistically significant factors that correlated with the appropriateness of referral. The referral method did not correlate with the appropriateness of referral. CONCLUSIONS Under the current health care system in South Korea, a substantial number of patients with presumed adolescent idiopathic scoliosis are referred either late or inappropriately to a tertiary medical center. Although patients referred by school screening programs had a significantly lower late referral rate and higher appropriate referral rate than the other 3 groups, the referral method was not a significant factor in terms of the appropriateness of referral.

Prospective assessment of the safety and early outcomes of sublaminar band placement for the prevention of proximal junctional kyphosis.

OBJECTIVE Proximal junctional kyphosis (PJK) can progress to proximal junctional failure (PJF), a widely recognized early and serious complication of multisegment spinal instrumentation for the treatment of adult spinal deformity (ASD). Sublaminar band placement has been suggested as a possible technique to prevent PJK and PJF but carries the theoretical possibility of a paradoxical increase in these complications as a result of the required muscle dissection and posterior ligamentous disruption. In this study, the authors prospectively assess the safety as well as the early clinical and radiological outcomes of sublaminar band insertion at the upper instrumented vertebra (UIV) plus 1 level (UIV+1). METHODS Between August 2015 and February 2017, 40 consecutive patients underwent either upper (T2-4) or lower (T8-10) thoracic sublaminar band placement at the UIV+1 during long-segment thoracolumbar arthrodesis surgery. Outcome measures were prospectively collected and uploaded to a web-based REDCap database specifically designed to include demographic, clinical, and radiological data. All patients underwent clinical assessment, as well as radiological assessment with anteroposterior and lateral 36-inch whole-spine standing radiographs both pre- and postoperatively. RESULTS Forty patients (24 women and 16 men) were included in this study. Median age at surgery was 64.0 years with an IQR of 57.7-70.0 years. Median follow-up was 12 months (IQR 6-15 months). Three procedure-related complications were noted, including 2 intraoperative cerebrospinal spinal fluid leaks and 1 transient neurological deficit. Median visual analog scale (VAS) scores for back pain significantly improved after surgery (preoperatively: 8.0, IQR 6.0-10.0; 1-year follow-up: 2.0, IQR 0.0-6.0; p = 0.001). Median Oswestry Disability Index (version 2.1a) scores also significantly improved after surgery (preoperatively: 56.0, IQR 45.0-64.0; 1-year follow-up: 46.0, IQR 22.2-54.0; p < 0.001). Sagittal vertical axis (preoperatively: 9.0 cm, IQR 5.3-11.6 cm; final follow-up: 4.7 cm, IQR 2.0-6.6 cm; p < 0.001), pelvic incidence-lumbar lordosis mismatch (24.7°, IQR 11.2°-31.2°; 7.7°, IQR -1.2° to 19.5°; p < 0.001), and pelvic tilt (28.7°, IQR 20.4°-32.6°; 17.1°, IQR 10.8°-25.2°; p < 0.001) were all improved at the final follow-up. While proximal junctional (PJ) Cobb angles increased overall at the final follow-up (preoperatively: 4.2°, IQR 1.9°-7.4°; final follow-up: 8.0°, IQR 5.8°-10.3°; p = 0.002), the significant increase was primarily noted starting at the immediate postoperative time point (7.2°, IQR 4.4°-11.8°; p = 0.001) and not beyond. Three patients (7.5%) developed radiological PJK (mean ΔPJ Cobb 15.5°), while there were no instances of PJF in this cohort. CONCLUSIONS Sublaminar band placement at the UIV+1 during long-segment thoracolumbar instrumented arthrodesis is relatively safe and is not associated with an increased rate of PJK. Moreover, no subjects developed PJF. Prospective large-scale and long-term analysis is needed to define the potential benefit of sublaminar bands in reducing the incidence of PJK and PJF following surgery for ASD. Clinical trial registration no.: NCT02411799 (clinicaltrials.gov).