Faculty Bibliography

OBJECTIVE:Rigid multiplanar thoracolumbar adult spinal deformity (ASD) cases are challenging and many require a 3-column osteotomy (3CO), specifically asymmetrical pedicle subtraction osteotomy (APSO). The outcomes and additional risks of performing APSO for the correction of concurrent sagittal-coronal deformity have yet to be adequately studied. METHODS:The authors performed a retrospective review of all ASD patients who underwent 3CO during the period from 2006 to 2019. All cases involved either isolated sagittal deformity (patients underwent standard PSO) or concurrent sagittal-coronal deformity (coronal vertical axis [CVA] ≥ 4.0 cm; patients underwent APSO). Perioperative and 2-year follow-up outcomes were compared between patients with isolated sagittal imbalance who underwent PSO and those with concurrent sagittal-coronal imbalance who underwent APSO. RESULTS:A total of 390 patients were included: 338 who underwent PSO and 52 who underwent APSO. The mean patient age was 64.6 years, and 65.1% of patients were female. APSO patients required significantly more fusions with upper instrumented vertebrae (UIV) in the upper thoracic spine (63.5% vs 43.3%, p = 0.007). Radiographically, APSO patients had greater deformity with more severe preoperative sagittal and coronal imbalance: sagittal vertical axis (SVA) 13.0 versus 10.7 cm (p = 0.042) and CVA 6.1 versus 1.2 cm (p < 0.001). In APSO cases, significant correction and normalization were achieved (SVA 13.0-3.1 cm, CVA 6.1-2.0 cm, lumbar lordosis [LL] 26.3°-49.4°, pelvic tilt [PT] 38.0°-20.4°, and scoliosis 25.0°-10.4°, p < 0.001). The overall perioperative complication rate was 34.9%. There were no significant differences between PSO and APSO patients in rates of complications (overall 33.7% vs 42.3%, p = 0.227; neurological 5.9% vs 3.9%, p = 0.547; medical 20.7% vs 25.0%, p = 0.482; and surgical 6.5% vs 11.5%, p = 0.191, respectively). However, the APSO group required significantly longer stays in the ICU (3.1 vs 2.3 days, p = 0.047) and hospital (10.8 vs 8.3 days, p = 0.002). At the 2-year follow-up, there were no significant differences in mechanical complications, including proximal junctional kyphosis (p = 0.352), pseudarthrosis (p = 0.980), rod fracture (p = 0.852), and reoperation (p = 0.600). CONCLUSIONS:ASD patients with significant coronal imbalance often have severe concurrent sagittal deformity. APSO is a powerful and effective technique to achieve multiplanar correction without higher risk of morbidity and complications compared with PSO for sagittal imbalance. However, APSO is associated with slightly longer ICU and hospital stays.

OBJECTIVE:There is an increased recognition of disproportional lumbar lordosis (LL) and artificially high pelvic incidence (PI) as a cause for positive sagittal imbalance and spinal pelvic mismatch. For such cases, a sacral pedicle subtraction osteotomy (PSO) may be indicated, although its morbidity is not well described. In this study, the authors evaluate the specific complication risks associated with S1 PSO. METHODS:A retrospective review of all adult spinal deformity patients who underwent a 3-column osteotomy (3CO) for thoracolumbar deformity from 2006 to 2019 was performed. Demographic, clinical baseline, and radiographic parameters were recorded. The primary outcome of interest was perioperative complications (surgical, neurological, and medical). Secondary outcomes of interest included case length, blood loss, and length of stay. Multivariate analysis was used to assess the risk of S1 PSO compared with 3CO at other levels. RESULTS:A total of 405 patients underwent 3CO in the following locations: thoracic (n = 55), L1 (n = 25), L2 (n = 29), L3 (n = 141), L4 (n = 129), L5 (n = 17), and S1 (n = 9). After S1 PSO, there were significant improvements in the sagittal vertical axis (14.8 cm vs 6.7 cm, p = 0.004) and PI-LL mismatch (31.7° vs 9.6°, p = 0.025) due to decreased PI (80.3° vs 65.9°, p = 0.006). LL remained unchanged (48.7° vs 57.8°, p = 0.360). The overall complication rate was 27.4%; the surgical, neurological, and medical complication rates were 7.7%, 6.2%, and 20.0%, respectively. S1 PSO was associated with significantly higher rates of overall complications: thoracic (29.1%), L1 (32.0%), L2 (31.0%), L3 (19.9%), L4 (32.6%), L5 (11.8%), and S1 (66.7%) (p = 0.018). Similarly, an S1 PSO was associated with significantly higher rates of surgical (thoracic [9.1%], L1 [4.0%], L2 [6.9%], L3 [5.7%], L4 [10.9%], L5 [5.9%], and S1 [44.4%], p = 0.006) and neurological (thoracic [9.1%], L1 [0.0%], L2 [6.9%], L3 [2.8%], L4 [7.0%], L5 [5.9%], and S1 [44.4%], p < 0.001) complications. On multivariate analysis, S1 PSO was independently associated with higher odds of overall (OR 7.93, p = 0.013), surgical (OR 20.66, p = 0.010), and neurological (OR 14.75, p = 0.007) complications. CONCLUSIONS:S1 PSO is a powerful technique for correction of rigid sagittal imbalance due to an artificially elevated PI in patients with rigid high-grade spondylolisthesis and chronic sacral fractures. However, the technique and intraoperative corrective maneuvers are challenging and associated with high surgical and neurological complications. Additional investigations into the learning curve associated with S1 PSO and complication prevention are needed.

OBJECTIVE:The correction of severe cervicothoracic sagittal deformities can be very challenging and can be associated with significant morbidity. Often, soft-tissue releases and osteotomies are warranted to achieve the desired correction. There is a paucity of studies that examine the difference in morbidity and complication profiles for Smith-Petersen osteotomy (SPO) versus 3-column osteotomy (3CO) for cervical deformity correction. METHODS:A retrospective comparison of complication profiles between posterior-based SPO (Ames grade 2 SPO) and 3CO (Ames grade 5 opening wedge osteotomy and Ames grade 6 closing wedge osteotomy) was performed by examining a single-surgeon experience from 2011 to 2018. Patients of interest were individuals who had a cervical sagittal vertical axis (cSVA) > 4 cm and/or cervical kyphosis > 20° and who underwent corrective surgery for cervical deformity. Multivariate analysis was utilized. RESULTS:A total of 95 patients were included: 49 who underwent 3CO and 46 who underwent SPO. Twelve of the SPO patients underwent an anterior release procedure. The patients' mean age was 63.2 years, and 60.0% of the patients were female. All preoperative radiographic parameters showed significant correction postoperatively: cSVA (6.2 cm vs 4.5 cm [preoperative vs postoperative values], p < 0.001), cervical lordosis (6.8° [kyphosis] vs -7.5°, p < 0.001), and T1 slope (40.9° and 35.2°, p = 0.026). The overall complication rate was 37.9%, and postoperative neurological deficits were seen in 16.8% of patients. The surgical and medical complication rates were 17.9% and 23.2%, respectively. Overall, complication rates were higher in patients who underwent 3CO compared to those who underwent SPO, but this was not statistically significant (total complication rate 42.9% vs 32.6%, p = 0.304; surgical complication rate 18.4% vs 10.9%, p = 0.303; and new neurological deficit rate 20.4% vs 13.0%, p = 0.338). Medical complication rates were similar between the two groups (22.4% [3CO] vs 23.9% [SPO], p = 0.866). Independent risk factors for surgical complications included male sex (OR 10.88, p = 0.014), cSVA > 8 cm (OR 10.36, p = 0.037), and kyphosis > 20° (OR 9.48, p = 0.005). Combined anterior-posterior surgery was independently associated with higher odds of medical complications (OR 10.30, p = 0.011), and preoperative kyphosis > 20° was an independent risk factor for neurological deficits (OR 2.08, p = 0.011). CONCLUSIONS:There was no significant difference in complication rates between 3CO and SPO for cervicothoracic deformity correction, but absolute surgical and neurological complication rates for 3CO were higher. A preoperative cSVA > 8 cm was a risk factor for surgical complications, and kyphosis > 20° was a risk factor for both surgical and neurological complications. Additional studies are warranted on this topic.

OBJECTIVE:The benefits and utility of routine neuromonitoring with motor and somatosensory evoked potentials during lumbar spine surgery remain unclear. This study assesses measures of performance and utility of transcranial motor evoked potentials (MEPs) during lumbar pedicle subtraction osteotomy (PSO). METHODS:This is a retrospective study of a single-surgeon cohort of consecutive adult spinal deformity (ASD) patients who underwent lumbar PSO from 2006 to 2016. A blinded neurophysiologist reviewed individual cases for MEP changes. Multivariate analysis was performed to determine whether changes correlated with neurological deficits. Measures of performance were calculated. RESULTS:A total of 242 lumbar PSO cases were included. MEP changes occurred in 38 (15.7%) cases; the changes were transient in 21 cases (55.3%) and permanent in 17 (44.7%). Of the patients with permanent changes, 9 (52.9%) had no recovery and 8 (47.1%) had partial recovery of MEP signals. Changes occurred at a mean time of 8.8 minutes following PSO closure (range: during closure to 55 minutes after closure). The mean percentage of MEP signal loss was 72.9%. The overall complication rate was 25.2%, and the incidence of new neurological deficits was 4.1%. On multivariate analysis, MEP signal loss of at least 50% was not associated with complication (p = 0.495) or able to predict postoperative neurological deficits (p = 0.429). Of the 38 cases in which MEP changes were observed, the observation represented a true-positive finding in only 3 cases. Postoperative neurological deficits without MEP changes occurred in 7 cases. Calculated measures of performance were as follows: sensitivity 30.0%, specificity 84.9%, positive predictive value 7.9%, and negative predictive value 96.6%. Regarding the specific characteristics of the MEP changes, only a signal loss of 80% or greater was significantly associated with a higher rate of neurological deficit (23.0% vs 0.0% for loss of less than 80%, p = 0.021); changes of less than 80% were not associated with postoperative deficits. CONCLUSIONS:Neuromonitoring has a low positive predictive value and low sensitivity for detecting new neurological deficits. Even when neuromonitoring is unchanged, patients can still have new neurological deficits. The utility of transcranial MEP monitoring for lumbar PSO remains unclear but there may be advantages to its use.

BACKGROUND:Dumbbell schwannomas of the thoracic spine are challenging to cure surgically. Surgeons are familiar with posterolateral approaches to the spine, however, these may provide inadequate exposure for large tumors extending to ventral extraspinal compartments. Ventrolateral transpleural approaches offer direct access to the ventral thoracic spine and intrathoracic cavity, though are associated with increased morbidity and pulmonary complications, and may necessitate a staged procedure in order to address concomitant dorsal pathology. Herein we describe our experience with single-stage, posterior approach to dumbbell schwannomas with large ventral extraspinal components, and review the literature regarding surgical approaches for these tumors. METHODS:Retrospective review of patients who underwent a single-stage, posterior spinal surgery for thoracic dumbbell schwannomas from 2008 to 2018. Inclusion criteria were age > 18 years and ventral thoracic tumor component. RESULTS:Three patients underwent a simultaneous retropleural thoracotomy and posterior spinal approach, through a single incision, for the resection of dumbbell (intradural and extradural) schwannomas. Mean age was 49.7 years and 2 patients were female. All patients were neurologically intact at baseline. Lesions were 4-8.2 cm in the largest dimension (mean 6.1 cm). GTR was achieved in all patients. One pleural rent occurred intraoperatively; there were no other intraoperative or perioperative complications. At a mean follow-up of 14.1 months all patients remained motor and sensory intact and there was no evidence of recurrence. CONCLUSIONS:The combined retropleural thoracotomy-posterior spinal approach provides safe and sufficient access for resection of large dumbbell schwannomas of the thoracic spine.

STUDY DESIGN/METHODS:Literature review. OBJECTIVE:The aim of this review is to summarize recent literature on adult spinal deformity (ASD) treatment failure as well as prevention strategies for these failure modes. SUMMARY OF BACKGROUND DATA/BACKGROUND:There is substantial evidence that ASD surgery can provide significant clinical benefits to patients. The volume of ASD surgery is increasing, and significantly more complex procedures are being performed, especially in the aging population with multiple comorbidities. Although there is potential for significant improvements in pain and disability with ASD surgery, these procedures continue to be associated with major complications and even outright failure. METHODS:A systematic search of the PubMed database was performed for articles relevant to failure after ASD surgery. Institutional review board approval was not needed. RESULTS:Failure and the potential need for revision surgery generally fall into 1 of 4 well-defined phenotypes: clinical failure, radiographic failure, the need for reoperation, and lack of cost-effectiveness. Revision surgery rates remain relatively high, challenging the overall cost-effectiveness of these procedures. CONCLUSION/CONCLUSIONS:By consolidating the key evidence regarding failure, further research and innovation may be stimulated with the goal of significantly improving the safety and cost-effectiveness of ASD surgery.

Introduction: The objective of this analysis was to compare sociodemographic characteristics and outcomes between cohorts of patients receiving separation surgery for spinal metastases at two neighboring institutions, one private and one public, affiliated with a major academic medical center in a large metropolitan area.
Method(s): Patients who received separation surgery for spinal metastases between 2013 and 2021 were included in this analysis. Sociodemographic factors, treatment characteristics, and outcomes were compared between those treated at a private hospital and those treated at a neighboring public hospital using Rao-Scott chi square tests.
Result(s): Compared to those treated at our private hospital, patients treated at our public hospital were more often younger (p=0.005), of Black or Hispanic race (70% vs. 14.9%, p<0.001), and insured via Medicaid or Emergency Medicaid (48.6% vs. 3.2%, p<0.001). They more frequently presented with ESCC grade 3 compression (81.6% vs. 49.2%), potentially unstable or unstable lesions as denoted by SINS >7 (64.1% vs. 37.7%), and increased neurologic impairment as denoted by ASIA Impairment Scale scores of A, B, or C (35% vs. 7.9%). Local progression was less frequently observed in patients treated at our public hospital (28.2% vs. 54.7%, p=0.001), although this is likely due to poorer clinical and radiographic follow-up amongst this cohort. Median survival was significantly lower in patients treated at our public hospital (Median [Range]: 81 [11-1,873] days vs. 264 [0-3,092] days, p<0.001), although this is also likely confounded by lower rates of follow-up.
Conclusion(s): This study highlights substantial disparities amongst patients treated for spinal metastases at neighboring institutions affiliated with a major academic medical center. Further work is needed to identify reasons for these disparities and create avenues by which to mitigate them

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.

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.

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.