Faculty Bibliography

OBJECTIVE:Long-segment fusion in adult spinal deformity (ASD) is often needed, but more focal surgeries may provide significant relief with less morbidity. The minimally invasive spinal deformity surgery (MISDEF2) algorithm guides minimally invasive ASD surgery, but it may be useful in open ASD surgery. We classified ASD patients undergoing focal decompression, limited decompression and fusion, and full correction according to MISDEF2 and correlated outcomes. METHODS:A retrospective study of ASD patients treated by 2 surgeons at our hospital was performed. Inclusion criteria were: age > 50, minimum 2-year follow-up, and open ASD surgery. Tumor, trauma, and infections were excluded. Patients had open surgery including focal decompression, short segment fusion, or full scoliosis correction. All patients were categorized by MISDEF2 into 4 classes based upon spinopelvic parameters. Perioperative metrics were assessed. Radiographic correction, complications and reoperation were recorded. RESULTS:A total of 136 patients met inclusion criteria. Mean follow-up was 46 ± 15.8 months (range, 24-118 months). Forty-seven underwent full deformity correction, 71 underwent short segment fusion, and 18 underwent decompression alone. There were 24 cases of class I, 66 cases of class II, 23 cases of class III, and 23 cases of class IV patients. Patients in class I and II had perioperative complication rates of 0% and 16.7% and revision rates of 8% and 21.2% when undergoing focal decompression or limited fusion. However, class II patients undergoing full correction had higher perioperative complications rate (p = 0.03) and revision surgery rates (p = 0.047). This difference was not seen in class III patients (p > 0.05). All class IV patients underwent full correction, but they had higher perioperative complication rates (p < 0.019), comparable revision surgery rates (p = 0.27), and better radiographic realignment (p < 0.001). In addition, full deformity correction was associated with longer length of stay, increased blood loss, and longer operative time (p < 0.001). CONCLUSION/CONCLUSIONS:The MISDEF2 algorithm may help guide ASD surgical decision making even in open surgery, with focal treatment used in class I and II patients as a viable alternative and full correction implemented in class IV patients because of severe malalignment. However, class II patients with ASD undergoing full deformity correction do have higher complication rates.

As we experience a technological revolution unlike any other time in history, spinal surgery as a discipline is poised to undergo a dramatic transformation. As enormous amounts of data become digitized and more readily available, medical professionals approach a critical juncture with respect to how advanced computational techniques may be incorporated into clinical practices. Within neurosurgery, spinal disorders in particular, represent a complex and heterogeneous disease entity that can vary dramatically in its clinical presentation and how it may impact patients' lives. The spectrum of pathologies is extremely diverse, including many different etiologies such as trauma, oncology, spinal deformity, infection, inflammatory conditions, and degenerative disease among others. The decision to perform spine surgery, especially complex spine surgery, involves several nuances due to the interplay of biomechanical forces, bony composition, neurologic deficits, and the patient's desired goals. Adult spinal deformity as an example is one of the most complex, given its involvement of not only the spine, but rather the entirety of the skeleton in order to appreciate radiographic completeness. With the vast array of variables contributing to spinal disorders, treatment algorithms can vary significantly, and it is very difficult for surgeons to predict how patients will respond to surgery. As such, it will become imperative for spine surgeons to utilize the burgeoning availability of advanced computational tools to process unprecedented amounts of data and provide novel insights into spinal disease. These tools range from predictive models built using machine learning algorithms, to deep learning methods for imaging analysis, to natural language processing that can mine text from electronic medical records or transcribed patient visits - all to better treat the intricacies of spinal disorders. The adoption of such techniques will empower patients and propel spine surgeons into the era of personalized medicine, by allowing clinical plans to be tailored to address individual patients' needs. This paper, which exists in the context of a larger body of literatutre, provides a comprehensive review of the current state and future of artificial intelligence and machine learning with a particular emphasis on Adult spinal deformity surgery.

The treatment of adult cervical deformity continues to be complex with high complication rates. However there are many new advancements and overall patients do well following surgical correction. To date there are now many types of cervical deformity that have been classified and there exists a variety of surgical options. These recent advances have been developed in the last few years and the field continues to grow at a rapid rate. Thus, the goal of this article is to provide an updated review of cervical sagittal balance including; cervical alignment parameters, deformity classification, clinical evaluation, with both conservative and surgical treatment options.

Adult spinal deformity (ASD) is a complex and heterogeneous disease that can severely impact patients' lives. While it is clear that surgical correction can achieve significant improvement of spinopelvic parameters and quality of life measures in adults with spinal deformity, there remains a high risk of complication associated with surgical approaches to adult deformity. Over the past decade, utilization of surgical correction for ASD has increased dramatically as deformity correction techniques have become more refined and widely adopted. Along with this increase in surgical utilization, there has been a massive undertaking by spine surgeons to develop more robust models to predict postoperative outcomes in an effort to mitigate the relatively high complication rates. A large part of this revolution within spine surgery has been the gradual adoption of predictive analytics harnessing artificial intelligence through the use of machine learning algorithms. The development of predictive models to accurately prognosticate patient outcomes following ASD surgery represents a dramatic improvement over prior statistical models which are better suited for finding associations between variables than for their predictive utility. Machine learning models, which offer the ability to make more accurate and reproducible predictions, provide surgeons with a wide array of practical applications from augmenting clinical decision making to more wide-spread public health implications. The inclusion of these advanced computational techniques in spine practices will be paramount for improving the care of patients, by empowering both patients and surgeons to more specifically tailor clinical decisions to address individual health profiles and needs.

BACKGROUND:Operative treatment of adult spinal deformity (ASD) can be very challenging with high complication rates. It is well established that patients benefit from such treatment; however, the surgical outcomes for patients with severe sagittal deformity have not been reported. OBJECTIVE:To report the outcomes of patients undergoing surgical correction for severe sagittal deformity. METHODS:Retrospective review of a prospective, multicenter ASD database. Inclusion criteria: operative patients age ≥18, sagittal vertical axis (SVA) ≥15 cm, mismatch between pelvic incidence and lumbar lordosis (PI-LL) ≥30°, and/or lumbar kyphosis ≥5° with minimum 2 yr follow-up. Health-related quality of life (HRQOL) scores including minimal clinically important difference (MCID)/substantial clinical benefit (SCB), sagittal and coronal radiographic values, demographic, frailty, surgical, and complication data were collected. Comparisons between 2 yr postoperative and baseline HRQOL/radiographic data were made. P < .05 was significant. RESULTS:A total of 138 patients were included from 502 operative patients (54.3% Female, Average (Avg) age 63.3 ± 11.5 yr). Avg operating room (OR) time 386.2 ± 136.5 min, estimated blood loss (EBL) 1829.8 ± 1474.6 cc. A total of 71(51.4%) had prior fusion. A total of 89.9% were posterior fusion only. Mean posterior levels fused 11.5 ± 4.1. A total of 44.9% had a 3-column osteotomy. All 2 yr postoperative radiographic parameters were significantly improved compared to baseline (P < .001 for all). All 2yr HRQOL measures were significantly improved compared to baseline (P < .004 for all). A total of 46.6% to 73.8% of patients met either MCID/SCB for all HRQOL. A total of 74.6% of patients had at least 1 complication, 11.6% had 4 or more complications, 33.3% had minimum 1 major complication, and 42(30.4%) had a postop revision. CONCLUSION/CONCLUSIONS:Patients with severe sagittal malalignment benefit from surgical correction at 2 yr postoperative both radiographically and clinically despite having a high complication rate.

Metastases cause 90% of human cancer deaths. The metastatic cascade involves local invasion, intravasation, extravasation, metastatic site colonization, and proliferation. Although individual mediators of these processes have been investigated, interactions between these mediators remain less well defined. We previously identified a complex between receptor tyrosine kinase c-Met and β1 integrin in metastases. Using cell culture and in vivo assays, we found that c-Met/β1 complex induction promoted intravasation and vessel wall adhesion in triple-negative breast cancer cells, but did not increase extravasation. These effects may have been driven by the ability of the c-Met/β1 complex to increase mesenchymal and stem cell characteristics. Multiplex transcriptomic analysis revealed upregulated Wnt and hedgehog pathways after c-Met/β1 complex induction. A β1 integrin point mutation that prevented binding to c-Met reduced intravasation. OS2966, a therapeutic antibody disrupting c-Met/β1 binding, decreased breast cancer cell invasion and mesenchymal gene expression. Bone-seeking breast cancer cells exhibited higher levels of c-Met/β1 complex than parental controls and preferentially adhered to tissue-specific matrix. Patient bone metastases demonstrated higher c-Met/β1 complex than brain metastases. Thus, the c-Met/β1 complex drove intravasation of triple-negative breast cancer cells and preferential affinity for bone-specific matrix. Pharmacological targeting of the complex may have prevented metastases, particularly osseous metastases.

PURPOSE:Evaluate costs and functional utility of post-discharge rehabilitation after surgery for adult spinal deformity (ASD). METHODS:Retrospective analysis of ASD patients who underwent operation at a single center and discharged to one rehabilitation facility. Operative details and costs were obtained for index inpatient encounter. Rehabilitation data included: direct costs, length of stay, and patient function, as assessed by Functional Independence Measure (FIM) instrument. RESULTS:Of 937 operations, 391 (41.7%) were discharged to rehabilitation. Ninety-patients (9.6%; 95 care episodes; average age 70.5 ± 10.6 years) were discharged to rehabilitation. Inpatient length of stay was 8.2 ± 2.6 days. Operative details: posterior levels fused 13.6 ± 3.6, PCOs/patient 7 ± 3.7, forty-two 3-column osteotomies, and 11 inter-body fusions. Direct costs were $90,738 ± $24,166 for index hospitalizations and $38,808 ± $14,752 for rehabilitation. Patients spent 11.7 ± 4.0 days in rehabilitation. Direct cost per day in hospital ($11,758 ± $3390) was significantly greater than rehabilitation ($3338 ± $2131) (p < 0.05). Significant improvements in function while in rehabilitation were observed (admit FIM: 66 ± 14 vs. discharge FIM: 94 ± 14). Charlson Comorbidity Index was the only independent predictor of rehabilitation direct costs. Conclusion Post-discharge inpatient rehabilitation following operations for ASD is associated with a direct cost of $38,808 per case. While rehabilitation resulted in significant functional improvements, it came at significant economic expense ($3.7 million) that accounted for 30% of costs for 95 episodes of care. For 100 operatively treated patients (assuming 41% discharge rate to rehab), rehabilitation results in an additional price premium of $1,674,872.

STUDY DESIGN/METHODS:International, multicenter, prospective, longitudinal observational cohort. OBJECTIVE:To assess how new motor deficits affect patient reported quality of life scores after adult deformity surgery. SUMMARY OF BACKGROUND DATA/BACKGROUND:Adult spinal deformity surgery is associated with high morbidity, including risk of new postoperative motor deficit. It is unclear what effect new motor deficit has on Health-related Quality of Life scores (HRQOL) scores. METHODS:Adult spinal deformity patients were enrolled prospectively at 15 sites worldwide. Other inclusion criteria included major Cobb more than 80°, C7-L2 curve apex, and any patient undergoing three column osteotomy. American Spinal Injury Association (ASIA) scores and standard HRQOL scores were recorded pre-op, 6 weeks, 6 months, and 2 years. RESULTS:Two hundred seventy two complex adult spinal deformity (ASD) patients enrolled. HRQOL scores were worse for patients with lower extremity motor score (LEMS). Mean HRQOL changes at 6 weeks and 2 years compared with pre-op for patients with motor worsening were: ODI (+12.4 at 6 weeks and -4.7 at 2 years), SF-36v2 physical (-4.5 at 6 weeks and +2.3 at 2 years), SRS-22r (0.0 at 6 weeks and +0.4 at 2 years). Mean HRQOL changes for motor-neutral patients were: ODI (+0.6 at 6 weeks and -12.1 at 2 years), SF-36v2 physical (-1.6 at 6 weeks and +5.9 at 2 years), and SRS-22r (+0.4 at 6 weeks and +0.7 at 2 years). For patients with LEMS improvement, mean HRQOL changes were: ODI (-0.6 at 6 weeks and -16.3 at 2 years), SF-36v2 physical (+1.0 at 6 weeks and +7.0 at 2 years), and SRS-22r (+0.5 at 6 weeks and +0.9 at 2 years). CONCLUSION/CONCLUSIONS:In the subgroup of deformity patients who developed a new motor deficit, total HRQOLs and HRQOL changes were negatively impacted. Patients with more than 2 points of LEMS worsening had the worst changes, but still showed overall HRQOL improvement at 6 months and 2 years compared with pre-op baseline.Level of Evidence: 3.

Adult cervical deformity management is complex and is a growing field with many recent advancements. The cervical spine functions to maintain the position of the head and plays a pivotal role in influencing subjacent global spinal alignment and pelvic tilt as compensatory changes occur to maintain horizontal gaze. There are various types of cervical deformity and a variety of surgical options available. The major advancements in the management of cervical deformity have only been around for a few years and continue to evolve. Therefore, the goal of this article is to provide a comprehensive review of cervical alignment parameters, deformity classification, clinical evaluation, and surgical treatment of adult cervical deformity. The information presented here may be used as a guide for proper preoperative evaluation and surgical treatment in the adult cervical deformity patient.

BACKGROUND:Rigid and ankylosed thoracolumbar spinal deformities require three-column osteotomy (3CO) to achieve adequate correction. For severe and multiregional deformities, multilevel 3CO is required but its use and outcomes are rarely reported. OBJECTIVE:To describe the use of multilevel pedicle subtraction osteotomy (PSO) in adult spinal deformity (ASD) patients with severe, rigid, and ankylosed multiregional deformity. METHODS:Retrospective review of 5 ASD patients who underwent multilevel PSO for the correction of severe fixed deformity and review the literature regarding the use of multilevel PSO. RESULTS:Five patients presented with spinal imbalance secondary to regional and multiregional spinal deformities involving the thoracolumbar spine. All patients underwent a single-stage two-level noncontiguous PSO, and 2 of the patients underwent a staged third PSO to treat deformity involving a separate spinal region. Significant radiographic correction was achieved with normalization of spinal alignment and parameters. Two-level PSO was able to provide greater than 80 degrees of sagittal plane correction in both the lumbar and thoracic spine. Two patients experienced new postoperative weakness which recovered to preoperative baseline at 3 to 6 mo follow-up. At most recent follow-up, 4 of the 5 patients gained significant pain relief and had improved functionality. CONCLUSION/CONCLUSIONS:Noncontiguous multilevel PSO is a formidable surgical technique. Additional risk (compared to single-level 3CO) comes in the form of greater blood loss and higher risk for postoperative weakness. Nonetheless, multilevel PSO is feasible and effective for correcting severe multiplanar and multiregional ASD, and patients gain significant benefits in increased functionality and pain relief.