Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:Investigate the patterns of fused lumbar alignment in patients requiring revision surgery for proximal junctional kyphosis (PJK). METHODS:Fifty patients (67.8 yo, 76% female) with existing thoraco-lumbar fusion (T10/12 to pelvis) and indicated for surgical correction for PJK were included. To investigate patterns of radiographic alignment prior to PJK revision, unsupervised 2-step cluster analysis was run on parameters describing the fused lumbar spine (PI-LL) to identify natural independent groups within the cohort. Clusters were compared in terms of demographics, pre-operative alignment, surgical parameters, and post-operative alignment. Associations between pre- and post-revision PJK angles were investigated using a Pearson correlation analysis. RESULTS:= 34, 68%) with a silhouette of .5. The comparison demonstrated similar pelvic incidence (PI) and PJK angle but significantly greater deformity for the UC vs OC group in terms of PI-LL, PI-LL offset, pelvic tilt, and sagittal vertebral axis. The surgical strategy for PJK correction did not differ between the 2 groups in terms of approach, American Society of Anesthesiologists grade, decompression, use of osteotomy, interbody fusion, or fusion length. The post-revision PJK angle significantly correlated with the amount of PJK correction within the OC group but not within the UC group. CONCLUSIONS:This study identified 2 patterns of lumbar malalignment associated with severe PJK: over vs under corrected. Despite the difference in PJK etiology, both patterns underwent the same revision strategy. Future analysis should look at the effect of correcting focal deformity alone vs correcting focal deformity and underlying malalignment simultaneously on recurrent PJK rate.

OBJECTIVE:Minimally invasive surgery (MIS) for adult spinal deformity (ASD) can offer deformity correction with less tissue manipulation and damage. However, the impact of obesity on clinical outcomes and radiographic correction following MIS for ASD is poorly understood. The goal of this study was to determine the role, if any, that obesity has on radiographic correction and health-related quality-of-life measures in MIS for ASD. METHODS:Data were collected from a multicenter database of MIS for ASD. This was a retrospective review of a prospectively collected database. Patient inclusion criteria were age ≥ 18 years and coronal Cobb angle ≥ 20°, pelvic incidence-lumbar lordosis mismatch ≥ 10°, or sagittal vertical axis (SVA) > 5 cm. A group of patients with body mass index (BMI) < 30 kg/m2 was the control cohort; BMI ≥ 30 kg/m2 was used to define obesity. Obesity cohorts were categorized into BMI 30-34.99 and BMI ≥ 35. All patients had at least 1 year of follow-up. Preoperative and postoperative health-related quality-of-life measures and radiographic parameters, as well as complications, were compared via statistical analysis. RESULTS:A total of 106 patients were available for analysis (69 control, 17 in the BMI 30-34.99 group, and 20 in the BMI ≥ 35 group). The average BMI was 25.24 kg/m2 for the control group versus 32.46 kg/m2 (p < 0.001) and 39.5 kg/m2 (p < 0.001) for the obese groups. Preoperatively, the BMI 30-34.99 group had significantly more prior spine surgery (70.6% vs 42%, p = 0.04) and worse preoperative numeric rating scale leg scores (7.71 vs 5.08, p = 0.001). Postoperatively, the BMI 30-34.99 cohort had worse Oswestry Disability Index scores (33.86 vs 23.55, p = 0.028), greater improvement in numeric rating scale leg scores (-4.88 vs -2.71, p = 0.012), and worse SVA (51.34 vs 26.98, p = 0.042) at 1 year postoperatively. Preoperatively, the BMI ≥ 35 cohort had significantly worse frailty (4.5 vs 3.27, p = 0.001), Oswestry Disability Index scores (52.9 vs 44.83, p = 0.017), and T1 pelvic angle (26.82 vs 20.71, p = 0.038). Postoperatively, after controlling for differences in frailty, the BMI ≥ 35 cohort had significantly less improvement in their Scoliosis Research Society-22 outcomes questionnaire scores (0.603 vs 1.05, p = 0.025), higher SVA (64.71 vs 25.33, p = 0.015) and T1 pelvic angle (22.76 vs 15.48, p = 0.029), and less change in maximum Cobb angle (-3.93 vs -10.71, p = 0.034) at 1 year. The BMI 30-34.99 cohort had significantly more infections (11.8% vs 0%, p = 0.004). The BMI ≥ 35 cohort had significantly more implant complications (30% vs 11.8%, p = 0.014) and revision surgery within 90 days (5% vs 1.4%, p = 0.034). CONCLUSIONS:Obese patients who undergo MIS for ASD have less correction of their deformity, worse quality-of-life outcomes, more implant complications and infections, and an increased rate of revision surgery compared with their nonobese counterparts, although both groups benefit from surgery. Appropriate counseling should be provided to obese patients.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:We hypothesized that adult spinal deformity (ASD) surgery would be associated with improved work- and school-related productivity, as well as decreased rates of absenteeism. SUMMARY OF BACKGROUND DATA/BACKGROUND:ASD patients experience markedly decreased health-related quality of life along many dimensions. METHODS:Only patients eligible for 2-year follow-up were included, and those with a history of previous spinal fusion were excluded. The primary outcome measures in this study were SRS-22r questions 9 and 17. A repeated measures mixed linear regression was used to analyze responses over time among patients managed operatively (OP) vs. non-operatively (NON-OP). RESULTS:In total, 1,188 patients were analyzed. 66.6% were managed operatively. At baseline, the mean percentage of activity at work/school was 56.4% (SD 35.4%), and the mean days off from work/school over the past 90 days was 1.6 (SD 1.8). Patients undergoing ASD surgery exhibited an 18.1% absolute increase in work/school productivity at 2-year follow-up vs. baseline (p < 0.0001), while no significant change was observed for the non-operative cohort (p > 0.5). Similarly, the OP cohort experienced 1.1 fewer absent days over the past 90 days at 2 years vs. baseline (p < 0.0001), while the NON-OP cohort showed no such difference (p > 0.3). These differences were largely preserved after stratifying by baseline employment status, age group, SVA, PI-LL, and deformity curve type. CONCLUSIONS:ASD patients managed operatively exhibited an average increase in work/school productivity of 18.1% and decreased absenteeism of 1.1 per 90 days at 2-year follow-up, while patients managed non-operatively did not exhibit change from baseline. Given the age distribution of patients in this study, these findings should be interpreted as pertaining primarily to obligations at work or within the home. Further study of the direct and indirect economic benefits of ASD surgery to patients is warranted.Level of Evidence: 3.

STUDY DESIGN/METHODS:Retrospective cohort study of a prospectively collected multi-center database of adult spinal deformity (ASD) patients. OBJECTIVE:We hypothesized that patients undergoing ASD surgery with and without previous spinal cord stimulators (SCS)/ intrathecal medication pumps (ITP) would exhibit increased complication rates but comparable improvement in health-related quality of life. SUMMARY OF BACKGROUND DATA/BACKGROUND:ASD patients sometimes seek pain management with SCS or ITP before spinal deformity correction. Few studies have examined outcomes in this patient population. METHODS:Patients undergoing ASD surgery and eligible for 2-year follow-up were included. Preoperative radiographs were reviewed for the presence of SCS/ITP. Outcomes included complications, Oswestry Disability Index (ODI), Short Form-36 Mental Component Score, and SRS-22r. Propensity score matching was utilized. RESULTS:In total, of 1034 eligible ASD patients, a propensity score-matched cohort of 60 patients (30 with SCS/ITP, 30 controls) was developed. SCS/ITP were removed intraoperatively in most patients (56.7%, n = 17). The overall complication rate was 80.0% versus 76.7% for SCS/ITP versus control (P > 0.2), with similarly nonsignificant differences for intraoperative and infection complications (all P > 0.2). ODI was significantly higher among patients with SCS/ITP at baseline (59.2 vs. 47.6, P = 0.0057) and at 2-year follow-up (44.4 vs. 27.7, P = 0.0295). The magnitude of improvement, however, did not significantly differ (P = 0.45). Similar results were observed for SRS-22r pain domain. Satisfaction did not differ between groups at either baseline or follow-up (P > 0.2). No significant difference was observed in the proportion of patients with SCS/ITP versus control reaching minimal clinically important difference in ODI (47.6% vs. 60.9%, P = 0.38). Narcotic usage was more common among patients with SCS/ITP at both baseline and follow-up (P < 0.05). CONCLUSION/CONCLUSIONS:ASD patients undergoing surgery with SCS/ITP exhibited worse preoperative and postoperative ODI and SRS-22r pain domain; however, the mean improvement in outcome scores was not significantly different from patients without stimulators or pumps. No significant differences in complications were observed between patients with versus without SCS/ITP.Level of Evidence: 3.

BACKGROUND:Disseminated intravascular coagulation (DIC) is a rare but serious complication of pediatric scoliosis surgery; sparse current evidence warrants more information on causality and prevention. This systematic review sought to identify incidence of DIC in pediatric patients during or shortly after corrective scoliosis surgery and identify any predictive factors for DIC. METHODS:Medline/PubMed, EMBASE, and Ovid databases were systematically reviewed through July 2017 to identify pediatric patients with DIC in the setting of scoliosis surgery. Patient demographics, medical history, surgery performed, clinical course, suspected causes of DIC, and outcomes were collected. RESULTS:= 7). The mortality rate was 7.69%; one fatality occurred in the acute postoperative period. CONCLUSIONS:Prior bleeding disorder status notwithstanding, this review identified preliminary associations between variables during corrective scoliosis surgery and DIC incidence among pediatric patients, suggesting multiple etiologies for DIC in the setting of scoliosis surgery. Further investigation is warranted to quantify associated risk. CLINICAL RELEVANCE/CONCLUSIONS:This study brings awareness to a previously rarely discussed complication of pediatric scoliosis surgery. Further cognizance of DIC by scoliosis surgeons may help identify and prevent causes thereof. LEVEL OF EVIDENCE: 4/METHODS/:

BACKGROUND:Adult spinal deformity (ASD) surgery can entail complex reconstructive procedures. It is unclear whether there is any effect of case start time on outcomes. We sought to evaluate the effects of case start time and day of the week on 90-day complication, readmission, and revision rates after ASD surgery. METHODS:This is a retrospective study of 1040 ASD patients from a single institution. We collected start times and day of the week for cases from 2011 to 2018. Early start was designated as any case starting either before or at 7:30 am or between 7:30 and 11 am; late start was designated as any case starting at 11 am or later. Outcome measures include 90-day complication, revision, and readmission rates. RESULTS:= 0.046). CONCLUSIONS:A late OR start time was predictive of increased risk for neurologic complication, 90-day readmission, and unplanned reoperation. The well-established protocols for first start OR times for elective ASD surgery may decrease outcome risk and reduce variability in complication rates. CLINICAL RELEVANCE/CONCLUSIONS:Understanding the impact of start time on outcomes and complications after ASD surgery is helpful for surgeons in preoperative planning and for institutions and hospitals' allocation of operating room staff and resources. LEVEL OF EVIDENCE/METHODS:3.

BACKGROUND:Prior studies of coccygectomy consist of small patient groups, heterogeneous techniques, and high wound complication rates (up to 22%). This study investigates our institution's experience with coccygectomy using a novel "off-center" wound closure technique and analyzes prognostic factors for long-term successful clinical outcomes. METHODS:Retrospective review of all patients who underwent coccygectomy from 2006 to 2019 at a single center. Demographics, mechanism of injury, conservative management, morphology (Postacchini and Massobrio), and postoperative complications were collected. Preoperative and postoperative Oswestry Disability Index (ODI), visual analog scale (VAS), Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29), and EuroQol-5D (EQ-5D) were compared. Risk factors for failing to meet minimum clinically importance difference for ODI and PROMIS-physical function/pain interference were identified. Risk factors for remaining disabled after surgery (ODI <20) and factors associated with VAS and EQ-5D improvement were investigated using stepwise logistic regression. RESULTS:<0.05). CONCLUSIONS:This is the largest series of coccygectomy patients demonstrating improvement in long-term outcomes. Compared to previous studies, our cohort had a lower wound infection rate, which we attribute to an "off-center" closure. CLINICAL RELEVANCE/CONCLUSIONS:Patients should be counseled that their surgical history, along with age, gender, and etiology of pain can influence success following coccygectomy. These data can help surgeons set realistic expectations following surgery. LEVEL OF EVIDENCE/METHODS:3.

Percutaneous cryoablation (PCA) is a minimally invasive technique that has been recently used to treat spinal metastases with a paucity of data currently available in the literature. A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Prospective or retrospective studies concerning metastatic spinal neoplasms treated with current generation PCA systems and with available data on safety and clinical outcomes were included. In the 8 included studies (7 retrospective, 1 prospective), a total of 148 patients (females = 63%) underwent spinal PCA. Tumors were located in the cervical (3/109 [2.8%], thoracic (74/109 [68.8%], lumbar (37/109 [33.9%], and sacrococcygeal (17/109 [15.6%] regions. Overall, 187 metastatic spinal lesions were treated. Thermo-protective measures (e.g., carbo-/hydro-dissection, thermocouples) were used in 115/187 [61.5%] procedures. For metastatic spinal tumors, the pooled mean difference (MD) in pain scores from baseline on the 0-10 numeric rating scale was 5.03 (95% confidence interval [CI]: 4.24 to 5.82) at a 1-month follow-up and 4.61 (95% CI: 3.27 to 5.95) at the last reported follow-up (range 24-40 weeks in 3/4 studies). Local tumor control rates ranged widely from 60% to 100% at varying follow-ups. Grade I-II complications were reported in 9/148 [6.1%] patients and grade III-V complications were reported in 3/148 [2.0%]) patients. PCA, as a stand-alone or adjunct modality, may be a viable therapy in appropriately selected patients with painful spinal metastases who were traditionally managed with open surgery and/or radiation therapy.

STUDY DESIGN/METHODS:Retrospective review of prospective longitudinal data. OBJECTIVE:To determine health-related quality of life (HRQL) utilities associated with specific ambulatory states in patients with spinal metastases: independent, ambulatory with assistance, and nonambulatory. SUMMARY OF BACKGROUND DATA/BACKGROUND:It is assumed that HRQL is aligned with ambulatory ability in patients with spinal metastases. Few studies have effectively considered these parameters while also accounting for clinical confounders. METHODS:We used prospective longitudinal data from patients treated at one of three tertiary medical centers (2017-2019). HRQL was characterized using the Euroquol-5-dimension (EQ5D) inventory. We performed standardized estimations of HRQL stratified by ambulatory state using generalized linear modeling that accounted for patient age at presentation, biologic sex, follow-up duration, operative or nonoperative management, and repeated measures within the same participant. RESULTS:We evaluated 675 completed EQ5D assessments, with 430 for independent ambulators, 205 for ambulators with assistance, and 40 for nonambulators. The average age of the cohort was 61.5. The most common primary cancer was lung (20%), followed by breast (18%). Forty-one percent of assessments were performed for participants treated surgically. Mortality occurred in 51% of the cohort. The standardized EQ5D utility for patients with spinal metastases and independent ambulatory function was 0.76 (95% confidence interval [CI] 0.74, 0.78). Among those ambulatory with assistance, the standardized EQ5D utility was 0.59 (95% CI 0.57, 0.61). For nonambulators, the standardized EQ5D utility was 0.14 (95% CI 0.09, 0.19). CONCLUSION/CONCLUSIONS:Patients with spinal metastases and independent ambulatory function have an HRQL similar to patients with primary cancers and no spinal involvement. Loss of ambulatory ability leads to a 22% decrease in HRQL for ambulation with assistance and an 82% reduction among nonambulators. Given prior studies demonstrate superior maintenance of ambulatory function with surgery for spinal metastases, our results support surgical consideration to the extent that it is clinically warranted.Level of Evidence: 3.

STUDY DESIGN/METHODS:Retrospective review of prospectively collected multicenter registry data. OBJECTIVE:The aim of this study was to determine whether surgical variables and complications as graded by treatment severity impact postoperative hospital length of stay (LOS). SUMMARY OF BACKGROUND DATA/BACKGROUND:Surgical treatment can substantially improve quality of life for patients with adult spinal deformity (ASD). However, surgical treatment is associated with high complication rates, which may impact hospital LOS. Classifying complications by severity of subsequent treatment may allow surgeons to better understand complications and predict their impact on important outcome metrics, including LOS. METHODS:Patients enrolled in a multicenter, prospectively enrolled database for ASD were assessed for study inclusion. Complications were graded based on intervention severity. Associations between LOS, complication intervention severity, and surgical variables (fusion length, use of interbody fusion, use of major osteotomy, primary versus revision surgery, same day vs. staged surgery, and surgical approach), were assessed. Two multivariate regression models were constructed to assess for independent associations with LOS. RESULTS:Of 1183 patients meeting inclusion criteria, 708 did not and 475 did experience a perioperative complication during their index hospitalization, with 660 and 436 included in the final cohorts, respectively. Among those with complications, intervention severities included 14.9% with no intervention, 68.6% with minor, 8.9% with moderate, and 7.6% with severe interventions. Multivariate regression modeling demonstrated that length of posterior fusion, use of major osteotomy, staged surgery, and severity of intervention for complications were significantly associated with LOS. CONCLUSION/CONCLUSIONS:Careful selection of surgical factors may help reduce hospital LOS following surgery for ASD. Classification of complications by treatment severity can help surgeons better understand and predict the implications of complications, in turn assisting with surgical planning and patient counseling.Level of Evidence: 4.