Faculty Bibliography

BACKGROUND CONTEXT: Increasing pelvic tilt (PT) is the main compensatory mechanism in sagittal spinal deformity. Traditionally PT>25degree has been considered pathologically high. Some adult spinal deformity (ASD) patients do not seem to improve their PT following ASD correction. However, the driving forces behind this lack of PT-response are not well defined. Previous studies have demonstrated a significant relationship between pelvic incidence (PI), age and alignment. PURPOSE: To investigate PT response following ASD surgery and its relationship to PI, age and alignment. STUDY DESIGN/SETTING: Retrospective review of a prospectively-collected ASD database. PATIENT SAMPLE: A total of 772 operative ASD patients with positive sagittal balance and 1-year follow up. OUTCOME MEASURES: Postoperative spinal alignment and SF36-PCS.
METHOD(S): A prospective database of operative ASD was analyzed. Patients with a baseline TPA >5degree from optimal were included. Regression models were developed to calculate optimal TPA (TPAo) and PT (PTo) for age and alignment. Similarly, the PT and TPA changes (MCIC) corresponding to the SF-36 PCS MCID were calculated. Two definitions for PT nonresponse were used: (1) Traditional: PT>25 at baseline and 1 year; (2) PT>PTo by 1 MCIC and PT change 20degree). PT responders were compared to non-responders in terms of PI and PCS offset (difference between actual and age-ideal PCS).
RESULT(S): A total of 772 patients met inclusion criteria (mean 64y, 75%F). 71% (n=548) had a pre-PT>25degree, 25% had a PI >65degree. PTo for each patient was calculated using the formula: PT=3.91-.01*Age+.101*PI+.701*TPA(R2=.82). Using the new PT definition, 45% had appropriate PT(PT=PTo) (PT>PTo: 22%).The MCIC for TPA and PT were 4.1degree and 2.9degree, respectively. At 1 year, 30% had a PT>25. 91 did not have MCIC for TPA and 34 had sPJK. Analysis of the remaining 103 nonresponders showed that 48% had a PI>65, 45% had a PT=PTo (PT>PTo: 51%). For patients with pre-PT>25 and 1 year PT>PTo (n=136), 27% had a PI>65, 26% had insufficient TPA correction, 27% had sPJK and 50% were >65y old. A total of 184 patients(24%) had a PT change 25 vs <25 groups at baseline or 1 year. Using the new PT definition, the PTPTo groups (-16.7 vs -14.8 vs -13.4, p<.05). At 1 year, among non-responders with adequate TPA correction, the PT>PTo group had worse PCS offset compared to the PT=PTo group (-9.5 vs.59, p<.05).
CONCLUSION(S): PT response in ASD surgery depends on change in spinal alignment but also age and PI and so it is patient specific. A PT within 2.9degree of optimal was considered appropriate. Nearly half of the 45% of patients traditionally considered to be PT nonresponders had an appropriate PT for age and alignment. A postoperative PT greater than optimal was associated with worse HRQL. This study's novel patient-specific method for defining PT response reveals that PT is not a one-size-fits-all parameter; it is imperative to consider the patient's PI, age and alignment. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Existing health outcome (HRQL) metrics fail to correlate with malalignment of the cervical spine and do not adequately capture disability from cervical deformity (CD). The purpose of this study is to introduce the cervical deformity patient generated index (PGI), where patients report their greatest difficulties related to their CD. These responses can then be used to identify the disabling features of CD that are not captured by existing HRQLs and determine items to be included in a CD specific HRQL. PURPOSE: To introduce the Cervical Deformity Patient Generated Index (PGI) to determine disabling features of CD that are appropriate for a CD specific HRQL. STUDY DESIGN/SETTING: Retrospective review of a prospective operative CD database and prospective development of a novel CD-PGI metric. PATIENT SAMPLE: A total of 139 CD patients and 12 PGI patients. OUTCOME MEASURES: Existing outcome metrics: NDI, NRS Back/Neck, mJOA, EQ5D, EQ5DVAS, and SWAL-QOL. Cervical Deformity Patient Generated Index (CD-PGI).
METHOD(S): CD patients completed the CD-PGI by describing the most important aspects of their disability. Patients wrote five things that bothered them most (Stage 1). Next patients rated the severity for each answer on a scale of 0 (max disability) to 10 (no disability) (Stage 2). Finally, patients "spent" up to 60 points on whichever responses they would like to improve (Stage 3). The PGI score was obtained by summing the product of Stage 2 and Stage 3 values for each response. PGI responses were categorized to find which aspects were most important to CD patients. A CD database was analyzed to assess whether legacy HRQLs correlate with cervical malalignment (CL, TSCL, cSVA, T1S, and C2S). Next PGI responses were analyzed to find how commonly responses were captured by existing cervical HRQL metrics: NDI, NRS Back/Neck, mJOA, EQ5D, EQ5DVAS and SWAL-QOL. Finally NDI and PGI were compared to elucidate major drivers of HRQL scores.
RESULT(S): A total of 139 CD patients (mean cSVA: 46.2mm) and 12 PGI patients (mean cSVA: 62mm) were included. PGI responses were grouped into 6 categories: Pain, Sagittal Discomfort/ROM, Horizontal Gaze/Walking Safety, Activities of Daily Living (ADL), Social Life and Hobbies and Neurologic. mJOA correlated with CL (r=0.21, p=0.01), TS-CL (r=-0.20, p=0.02), and C2S (r=-0.18, p=0.03). PGI scores did not correlate with any HRQLs. 34/60 PGI responses (57%) were found to be captured by existing HRQLs. The EQ5D addressed 53% of PGI responses compared to 43% for NDI, 3% for mJOA address and 0% for SWALQOL. PGI-Pain, -neurologic, -social life, and -ADL responses were addressed by existing HRQLs. However, only 40% horizontal gaze and 0% sagittal discomfort responses were addressed. The main drivers of NDI score were reading, pain, and recreation questions, explaining 80% of variability (r2=0.80). The main drivers of PGI were ADL, sagittal discomfort and social life, explaining 75% of variability (r2=0.75). NDI-Concentration NDI-Reading, NDI-Driving and NDI-Sleep correlated with multiple individual PGI items including PGI-ADL, -sagittal discomfort, and -social life (all r>.75, p<.05).
CONCLUSION(S): Existing HRQL do not adequately capture CD disability and do not correlate with cervical malalignment. PGI items not addressed in existing HRQLs include Sagittal Discomfort/ROM and Horizontal Gaze/Walking Safety. In addition, the most important categories driving PGI scores were found to be ADLs, Sagittal Discomfort/ROM, and Social Life/Hobbies. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: While corrective procedures for cervical deformity (CD) have significantly advanced, little is known what impact neurologic sequlae have on the postoperative recovery process. PURPOSE: Investigate which neurologic complications affect clinical outcomes the most following CD surgery. STUDY DESIGN/SETTING: Retrospective review of a prospective multicenter adult cervical deformity database. PATIENT SAMPLE: A total of 66 operative adult CD patients. OUTCOME MEASURES: Neurologic complication rates and Integrated Health State for the Neck Disability Index (NDI), EuroQol-5D (EQ-5D), and the Modified Japanese Orthopedic Association score (mJOA).
METHOD(S): CD patients (C2-C7 Cobb>10degree, CL>10degree, cSVA>4cm, or CBVA>25degree)>18yr with follow up surgical and HRQL data were included. Descriptive analyses assessed demographics. Neuro comps assessed were: C5 motor deficit, central neuro deficit, nerve root motor deficits, nerve sensory deficits, radiculopathy and spinal cord deficits. Neuro comps were classified as major (M) or minor, then: intra-operative, before discharge, before 30 days, before 90 days, and after 90 days. The rates of persistent neurologic deficits were assessed at 1 and 2 years. HRQL outcomes were assessed at 3M, 6M, 1Y and 2Y. Integrated health state (IHS) for the NDI, EQ5D, and mJOA were assessed using all follow up time points.
RESULT(S): A total of 66 operative CD patients were included. Baseline demo and surgery data: 61 years old, 63% female, BMI 29.7, op time 531.6 +/- 275.5, EBL 924.2 +/- 729.5, 49% posterior only approach, 18% anterior only approach, 33% combined. 34 (21%) patients experienced a total of 31 neurologic complications in the postoperative period (15M). In total, there were 7 radiculopathy, 6 motor deficits, 6 sensory deficits, 5 C5 motor deficits, 2 central neuro deficits, 2 spinal cord deficits, and 2 other. Motor deficits were the most common major complication (8), 4 of which were C5. Of the intraoperative complications, there were 3M, while 23% of patients had complications before discharge (5M). A total of 39% of neurologic complications occurred before 30 days (7M) and 71% before 90 days (12M), 16% were after 90 days (2M). A total of 12% of neuro comp patients went on to have revision surgery within 6 months, and 18% within 2 years. While normalized 6M mJOA scores were worse between neuro comp and no comp patients (1.00 +/- 0.12 vs 1.11 +/- 0.19, p=0.024), there was no significant difference in 2Y IHS for the NDI, EQ5D or mJOA (all p>0.05). When assessing individual comps, central neurologic deficits and spinal cord deficit patients had the worst outcomes at 1Y (2.6 and 1.8 times worse normalized NDI scores, p=0.04, no improvement in EQ5D, 8% decrease in EQ5D). Patients with sensory deficits had the best NDI and EQ5D outcomes at 1Y (31% decrease in NDI, 8% increase in EQ5D). One-half of neuro comp patients had persistent neurologic deficits at 1Y, and 21% at 2Y, however, there was no difference in outcomes at any time point (all p>0.05). Experiencing a nerve sensory deficit or spinal cord deficit correlated with revision surgery (r=0.241, 0.283, p<0.05).
CONCLUSION(S): A total of 21% of patients undergoing CD surgery experienced a neurologic complication, with 71% occurring within 6 months. While patients who experienced any neurologic complication had worse mJOA scores at 6M, there was no significant difference in recovery kinetics at 2Y. Of the neurologic complications, central neurologic deficits and spinal cord deficits were the most detrimental. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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Total uncinate process resection or uncinectomy is often required in the setting of severe foraminal stenosis or cervical kyphosis correction. The proximity of the uncus to the vertebral artery, nerve root, and spinal cord makes this a challenging undertaking. Use of a high-speed burr or ultrasonic bone dissector can be associated with direct injury to the vertebral artery and thermal injury to the surrounding structures. The use of an osteotome is a safe and efficient method of uncinectomy. Here the authors describe their technique, which is illustrated with an intraoperative video.

OBJECTIVE:Obesity, a condition that is increasing in prevalence in the United States, has previously been associated with poorer outcomes following deformity surgery, including higher rates of perioperative complications such as deep and superficial infections. To date, however, no study has examined the relationship between preoperative BMI and outcomes of deformity surgery as measured by spine parameters such as the sagittal vertical axis (SVA), as well as health-related quality of life (HRQoL) measures such as the Oswestry Disability Index (ODI) and Scoliosis Research Society-22 patient questionnaire (SRS-22). To this end, the authors sought to clarify the relationship between BMI and postoperative change in SVA as well as HRQoL outcomes. METHODS:The authors performed a retrospective review of a prospectively managed multicenter adult spinal deformity database collected and maintained by the International Spine Study Group (ISSG) between 2009 and 2014. The primary independent variable considered was preoperative BMI. The primary outcome was the change in SVA at 1 year after deformity surgery. Postoperative ODI and SRS-22 outcome measures were evaluated as secondary outcomes. Generalized linear models were used to model the primary and secondary outcomes at 1 year as a function of BMI at baseline, while adjusting for potential measured confounders. RESULTS:Increasing BMI (compared to BMI < 18) was not associated with change of SVA at 1 year postsurgery. However, BMIs in the obese range of 30 to 34.9 kg/m2, compared to BMI < 18 at baseline, were associated with poorer outcomes as measured by the SRS-22 score (estimated change -0.47, 95% CI -0.93 to -0.01, p = 0.04). While BMIs > 30 appeared to be associated with poorer outcomes as determined by the ODI, this correlation did not reach statistical significance. CONCLUSIONS:Baseline BMI did not affect the achievable SVA at 1 year postsurgery. Further studies should evaluate whether even in the absence of a change in SVA, baseline BMIs in the obese range are associated with worsened HRQoL outcomes after spinal surgery.

Study Design/UNASSIGNED:Prospective cohort study. Objectives/UNASSIGNED:Most studies of dysphagia in the cervical spine have focused on a degenerative patient population; the rate of dysphagia following surgery for cervical deformity (CD) is unknown. This study aims to investigate if surgery for cervical deformity results in postoperative dysphagia. Methods/UNASSIGNED:tests, and bivariate Pearson correlations were performed. Results/UNASSIGNED:= .53). Surgical variables, including estimated blood loss (EBL), anterior or posterior fusion levels, steroid use, preoperative traction, staged surgery, surgical approach, anterior corpectomy, posterior osteotomy, and UIV (upper instrumented vertebrae) location, showed no impact on postoperative SWAL-QoL. Correction of cervical kyphosis was not correlated to 3-month SWAL-QoL scores or the change in SWAL-QoL scores. Conclusions/UNASSIGNED:While patients undergoing surgery for cervical deformity had swallowing dysfunction at baseline, we did not observe a significant decline in SWAL-QoL scores at 3 months. Patients with prior cervical surgery and higher BMI had a lower baseline SWAL-QoL. There were no surgical or radiographic variables correlated to a change in SWAL-QOL score.

MINI: The ability of PROMIS to capture disability from cervical sagittal malalignment is unknown. Correlations between PROMIS domains and legacy outcome metrics with cervical sagittal alignment parameters were analyzed. PROMIS domains correlated strongly with legacy outcomes and PROMIS Pain Intensity correlated with worsening sagittal alignment in patients with cervical sagittal deformity.

BACKGROUND:Patients undergoing multilevel spine surgery are at risk for delayed extubation. OBJECTIVE:To evaluate the impact of type and volume of intraoperative fluids administered during multilevel thoracic and/or lumbar spine surgery on postoperative extubation status. METHODS:Retrospective evaluation of medical records of patients ≥ 18 yr undergoing ≥ 4 levels of thoracic and/or lumbar spine fusions was performed. Patients were organized according to postoperative extubation status: immediate (IMEX; in OR/PACU) or delayed (DEX; outside OR/PACU). Propensity score matched (PSM) analysis was performed to compare IMEX and DEX groups. Volume, proportion, and ratios of intraoperative fluids administered were evaluated for the associated impact on extubation status. RESULTS:A total of 246 patients (198 IMEX, 48 DEX) were included. PSM analysis demonstrated that increased administration of non-cell saver blood products (NCSB) and increased ratio of crystalloid: colloids infused were independently associated with delayed extubation. With increasing EBL, IMEX had a proportionate reduction in crystalloid infusion (R = -0.5, P < .001), while the proportion of crystalloids infused remained relatively unchanged for DEX (R = -0.27; P = .06). Twenty-six percent of patients receiving crystalloid: colloid ratio > 3:1 had DEX compared to none of those receiving crystalloid: colloid ratio ≤ 3:1 (P = .009). DEX had greater cardiac and pulmonary complications, surgical site infections and prolonged intensive care unit and hospital stay (P < .05). CONCLUSION/CONCLUSIONS:PSM analysis of patients undergoing multilevel thoracic and/or lumbar spine fusion demonstrated that increased administration of crystalloid to colloid ratio is independently associated with delayed extubation. With increasing EBL, a proportionate reduction of crystalloids facilitates early extubation.

BACKGROUND:Limited data are available to objectively define what constitutes a "good" versus a "bad" recovery for operative cervical deformity (CD) patients. Furthermore, the recovery patterns of primary versus revision procedures for CD is poorly understood. OBJECTIVE:To define and compare the recovery profiles of CD patients undergoing primary or revision procedures, utilizing a novel area-under-the-curve normalization methodology. METHODS:CD patients undergoing primary or revision surgery with baseline to 1-yr health-related quality of life (HRQL) scores were included. Clinical symptoms and HRQL were compared among groups (primary/revision). Normalized HRQL scores at baseline and follow-up intervals (3M, 6M, 1Y) were generated. Normalized HRQLs were plotted and area under the curve was calculated, generating one number describing overall recovery (Integrated Health State). Subanalysis identified recovery patterns through 2-yr follow-up. RESULTS:Eighty-three patients were included (45 primary, 38 revision). Age (61.3 vs 61.9), gender (F: 66.7% vs 63.2%), body mass index (27.7 vs 29.3), Charlson Comorbidity Index, frailty, and osteoporosis (20% vs 13.2%) were similar between groups (P > .05). Primary patients were more preoperatively neurologically symptomatic (55.6% vs 31.6%), less sagittally malaligned (cervical sagittal vertical axis [cSVA]: 32.6 vs 46.6; T1 slope: 28.8 vs 36.8), underwent more anterior-only approaches (28.9% vs 7.9%), and less posterior-only approaches (37.8% vs 60.5%), all P < .05. Combined approaches, decompressions, osteotomies, and construct length were similar between groups (P > .05). Revisions had longer op-times (438.0 vs 734.4 min, P = .008). Following surgery, complication rate was similar between groups (66.6% vs 65.8%, P = .569). Revision patients remained more malaligned (cSVA, TS-CL; P < .05) than primary patients until 1-yr follow-up (P > .05). Normalized HRQLs determined primary patients to exhibit less neck pain (numeric rating scale [NRS]) and myelopathy (modified Japanese Orthopaedic Association) symptoms through 1-yr follow-up compared to revision patients (P < .05). These differences subsided when following patients through 2 yr (P > .05). Despite similar 2-yr HRQL outcomes, revision patients exhibited worse neck pain (NRS) Integrated Health State recovery (P < .05). CONCLUSION/CONCLUSIONS:Despite both primary and revision patients exhibiting similar HRQL outcomes at final follow-up, revision patients were in a greater state of postoperative neck pain for a greater amount of time.

S1 pedicle subtraction osteotomies (PSOs) are indicated in patients with fixed, high-grade L5-S1 spondylolisthesis or kyphosis secondary to a sacral fracture, who present with severe sagittal imbalance. Unlike lumbar PSOs, sacral osteotomies are rare, and there is a paucity of literature outlining techniques. Here, we present the indications, planning, technique, and outcomes for S1 PSOs.