Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective review. OBJECTIVE:The aim of this study was to develop a novel surgical invasiveness index for cervical deformity (CD) surgery that incorporates CD-specific parameters. SUMMARY OF BACKGROUND DATA/BACKGROUND:There has been a surgical invasiveness index for general spine surgery and adult spinal deformity, but a CD index has not been developed. METHODS:CD was defined as at least one of the following: C2-C7 Cobb > 10°, cervical lordosis (CL) > 10°, cervical sagittal vertical axis (cSVA) > 4 cm, chin brow vertical angle (CBVA) > 25°. Consensus from experienced spine and neurosurgeons selected weightings for each variable that went into the invasiveness index. Binary logistic regression predicted high operative time (>338 minutes), estimated blood loss (EBL) (>600 cc), or length of stay (LOS; > 5 days) based on the median values of operative time, EBL and LOS. Multivariable regression modeling was utilized to construct a final model incorporating the strongest combination of factors to predict operative time, LOS, and EBL. RESULTS:85 CD patients were included (61yrs, 66%F). The variables in the newly developed CD invasiveness index with their corresponding weightings were: history of prior cervical surgery (3), anterior cervical discectomy and fusion (ACDF) (2/level), corpectomy (4/level), levels fused (1/level), implants (1/level), posterior decompression (2/level), Smith-Peterson osteotomy (2/level), three column osteotomy (8/level), fusion to upper cervical spine (2), absolute change in T1 slope minus cervical lordosis (TS-CL), cSVA, T4-T12 thoracic kyphosis and sagittal vertical axis (SVA) from baseline to 1-year. The newly developed CD-specific invasiveness index strongly predicted long LOS (R = 0.310, p < 0.001), high EBL (R = 0.170, p = 0.011), and extended operative time (R = 0.207, p = 0.031). A second analysis used multivariable regression modeling to determine which combination of factors in the newly developed index were the strongest determinants of operative time, LOS, and EBL. The final predictive model included: number of corpectomies, levels fused, decompression, combined approach, and absolute changes in SVA, cSVA and TK. This model predicted EBL (R = 0.26), operative time (R = 0.12), and LOS (R = 0.13). CONCLUSIONS:Extended length of stay, operative time, and high blood loss were strongly predicted by the newly developed CD invasiveness index, incorporating surgical factors and radiographic parameters clinically relevant for patients undergoing cervical deformity corrective surgery. LEVELS OF EVIDENCE/METHODS:4.

BACKGROUND:Proximal junctional kyphosis (PJK) is a common radiographic complication of adult spinal deformity (ASD) corrective surgery. Although previous literature has reported a 5 to 61% incidence of PJK, these studies are limited by small sample sizes and short-term follow-up. OBJECTIVE:To assess the incidence of PJK utilizing a high-powered ASD database. METHODS:Retrospective review of a prospective multicenter ASD database. Operative ASD patients > 18 yr old from 2009 to 2017 were included. PJK was defined as ≥ 10° for the sagittal Cobb angle between the inferior upper instrumented vertebra (UIV) endplate and the superior endplate of the UIV + 2. Chi-square analysis and post hoc testing assessed annual and overall incidence of acute (6-wk follow-up [f/u]), progressive (increase in degree of PJK from 6 wk to 1 yr), and delayed (1-yr, 2-yr, and 3-yr f/u) PJK development. RESULTS:A total of 1005 patients were included (age: 59.3; 73.5% F; body mass index: 27.99). Overall PJK incidence was 69.4%. Overall incidence of acute PJK was 48.0%. Annual incidence of acute PJK has decreased from 53.7% in 2012 to 31.6% in 2017 (P = .038). Overall incidence of progressive PJK was 35.0%, with stable rates observed from 2009 to 2016 (P = .297). Overall incidence of 1-yr-delayed PJK was 9.3%. Annual incidence of 1-yr-delayed PJK has decreased from 9.2% in 2009 to 3.2% in 2016 (P < .001). Overall incidence of 2-yr-delayed PJK development was 4.3%. Annual incidence of 2-yr-delayed PJK has decreased from 7.3% in 2009 to 0.9% in 2015 (P < .05). Overall incidence of 3-yr-delayed PJK was 1.8%, with stable rates observed from 2009 to 2014 (P = .594). CONCLUSION/CONCLUSIONS:Although progressive PJK has remained a challenge for physicians over time, significantly lower incidences of acute and delayed PJK in recent years may indicate improving operative decision-making and management strategies.

BACKGROUND:Distal junctional kyphosis (DJK) development after cervical deformity (CD)-corrective surgery is a growing concern for surgeons and patients. Few studies have investigated risk factors that predict the occurrence of DJK. OBJECTIVE:To predict DJK development after CD surgery using predictive modeling. METHODS:CD criteria was at least one of the following: C2-C7 Coronal/Cobb > 10°, C2-7 sagittal vertical axis (cSVA) > 4 cm, chin-brow vertical angle > 25°. DJK was defined as the development of an angle <-10° from the end of fusion construct to the second distal vertebra, and change in this angle by <-10° from baseline to postoperative. Baseline demographic, clinical, and surgical information were used to predict the occurrence of DJK using generalized linear modeling both as one overall model and as submodels using baseline demographic and clinical predictors or surgical predictors. RESULTS:One hundred seventeen CD patients were included. At any postoperative visit up to 1 yr, 23.1% of CD patients developed DJK. DJK was predicted with high accuracy using a combination of baseline demographic, clinical, and surgical factors by the following factors: preoperative neurological deficit, use of transition rod, C2-C7 lordosis (CL)<-12°, T1 slope minus CL > 31°, and cSVA > 54 mm. In the model using only baseline demographic/clinical predictors of DJK, presence of comorbidities, presence of baseline neurological deficit, and high preoperative C2-T3 angle were included in the final model (area under the curve = 87%). The final model using only surgical predictors for DJK included combined approach, posterior upper instrumented vertebrae below C4, use of transition rod, lack of anterior corpectomy, more than 3 posterior osteotomies, and performance of a 3-column osteotomy. CONCLUSION/CONCLUSIONS:Preoperative assessment and consideration should be given to these factors that are predictive of DJK to mitigate poor outcomes.

The elderly are the largest segment of patients undergoing spine surgery and are expected to continue to grow with time. Proper preoperative evaluation of the elderly is something every spine surgeon will need to be adept at. Evaluating and optimizing an elderly patient leads to greater patient satisfaction, decreased postoperative complications and overall mortality. Age, while traditionally thought to predict preoperative risk, has consistently been a poor predictor of complications in spine patients. The concept of frailty and various related clinical tools have been developed and consistently validated to predict a given patient's capacity to successfully undergo surgery.

Occipital neuralgia typically arises in the setting of nerve compression by fibrosis, surrounding anatomic structures, or osseous pathology, such as bone spurs or hypertrophic atlanto-epistropic ligament. It generally presents as paroxysmal bouts of sharp pain in the sensory distribution of the first three occipital nerves. Due to the long course of the greater occipital nerve (GON), and its peculiar anatomy, and location in a mobile region of the neck, it is unsurprising that the GON is at high risk for compression. Little is known how to diagnose or treat this neuropathic pain syndrome. The objective of this paper is to isolate the etiology involved, and treat this condition promptly. After all nonoperative efforts are exhausted, surgical transection of the nerve is the treatment of choice in these cases. An isolated C2 neurectomy or ganglionectomy is performed for an optimal pain relief. C1-2 instrumented fusion can be considered if, extensive facet arthropathy with instability is identified. Authors review the spectrum of treatment options for this debilitating condition, and discuss the case example of a patient who required conversion to a C1-C2 instrumented fusion following C2 ganglionectomy due to an underlying extensive degenerative disease and intraoperative findings suggestive of atlantoaxial instability.

BACKGROUND CONTEXT/BACKGROUND:Laboratory values have been found to be useful predictive measures of survival following surgery. The utility of laboratory values for prognosticating outcomes among patients with spinal metastases has not been studied. PURPOSE/OBJECTIVE:To determine the prognostic capacity of laboratory values at presentation including white blood cell count, serum albumin and platelet-lymphocyte ratio (PLR) in patients with spinal metastases. STUDY DESIGN/METHODS:Retrospective review of records from two tertiary care centers (2005-2017). PATIENT SAMPLE/METHODS:Patients, aged 40 to 80, who received operative or nonoperative management for spinal metastases. OUTCOME MEASURES/METHODS:Survival, complications, or hospital readmissions within 90 days of treatment and a composite measure for treatment failure accounting for changes in ambulatory function and mortality at 6 months following presentation. METHODS:Multivariable Cox proportional hazard regression analysis was used to analyze the relationship between laboratory values and length of survival, adjusting for confounders. Multivariable logistic regression was used in analyses related to 6-month and 1-year mortality, complications, readmissions, and treatment failure. A scoring rubric was developed based on the performance of laboratory values in the multivariable tests. Internal validation was performed using a bootstrap simulation that consisted of sampling with replacement and 1,000 replications. RESULTS:We included 1,216 patients. Thirty-seven percent of patients received a surgical intervention and 63% were treated nonoperatively. Median survival for the cohort as a whole was 255 days (interquartile range 93-642 days). The PLR (hazard ratio [HR] 1.53; 95% confidence interval [CI] 1.29, 1.80; p<.001) and albumin (HR 0.54; 95% CI 0.45, 0.64; p<.001) were significantly associated with survival, whereas WBC count (HR 1.08; 95% CI 0.86, 1.36; p=.50) was not associated with this outcome. Similar findings were encountered for 6-month and 1-year mortality as well as the composite measure for treatment failure. The PLR and albumin performed well in our scoring rubric and findings were preserved in the bootstrapping validation. CONCLUSIONS:Individuals with low serum albumin and elevated PLR should be advised regarding the impact of these laboratory markers on outcomes including survival, irrespective of treatments received. An effort should also be made to optimize nutrition and PLR, if practicable, before treatment to minimize the potential for development of adverse events.

Cervical alignment plays a critical role in the diagnosis and treatment of spinal pathology. There has been a proliferation of novel radiographic parameters to quantify cranial and cervical alignment. These parameters have been placed in clinical context by their correlation with health-related quality of life (HRQOL) scores. This article reviews these parameters and describes their utility in understanding spinal deformity and other pathologies of the cervical spine.

OBJECTIVE:Optimal patient selection for upper-thoracic (UT) versus lower-thoracic (LT) fusion during adult spinal deformity (ASD) correction is challenging. Radiographic and clinical outcomes following UT versus LT fusion remain incompletely understood. The purposes of this study were: 1) to evaluate demographic, radiographic, and surgical characteristics associated with choice of UT versus LT fusion endpoint; and 2) to evaluate differences in radiographic, clinical, and health-related quality of life (HRQOL) outcomes following UT versus LT fusion for ASD. METHODS:Retrospective review of a prospectively collected multicenter ASD database was performed. Patients with ASD who underwent fusion from the sacrum/ilium to the LT (T9-L1) or UT (T1-6) spine were compared for demographic, radiographic, and surgical characteristics. Outcomes including proximal junctional kyphosis (PJK), reoperation, rod fracture, pseudarthrosis, overall complications, 2-year change in alignment parameters, and 2-year HRQOL metrics (Lumbar Stiffness Disability Index, Scoliosis Research Society-22r questionnaire, Oswestry Disability Index) were compared after controlling for confounding factors via multivariate analysis. RESULTS:Three hundred three patients (169 LT, 134 UT) were evaluated. Independent predictors of UT fusion included greater thoracic kyphosis (odds ratio [OR] 0.97 per degree, p = 0.0098), greater coronal Cobb angle (OR 1.06 per degree, p < 0.0001), and performance of a 3-column osteotomy (3-CO; OR 2.39, p = 0.0351). While associated with longer operative times (ratio 1.13, p < 0.0001) and greater estimated blood loss (ratio 1.31, p = 0.0018), UT fusions resulted in greater sagittal vertical axis improvement (-59.5 vs -41.0 mm, p = 0.0035) and lower PJK rates (OR 0.49, p = 0.0457). No significant differences in postoperative HRQOL measures, reoperation, or overall complication rates were detected between groups (all p > 0.1). CONCLUSIONS:Greater deformity and need for 3-CO increased the likelihood of UT fusion. Despite longer operative times and greater blood loss, UT fusions resulted in better sagittal correction and lower 2-year PJK rates following surgery for ASD. While continued surveillance is necessary, this information may inform patient counseling and surgical decision-making.

STUDY DESIGN/METHODS:Retrospective cohort. OBJECTIVE:Identify the nonradiographic predictors of a patient's decision to undergo elective spine surgery. SUMMARY OF BACKGROUND DATA/BACKGROUND:Up to 132 million people seek elective evaluation by spine surgeons annually, though 55%-82% of specialty referrals may be inappropriate. We sought to determine which clinical and psychosocial factors are associated with surgical utilization by patients seeking surgical evaluation for degenerative spine pathologies. MATERIALS AND METHODS/METHODS:Consecutive elective outpatient visits seen in a single clinic between May 2016 and April 2017 for degenerative spine pathologies were reviewed. Data were collected on presenting symptoms, baseline medical illness, demographics, and previous spine care. Multivariable logistic regressions were performed to determine which factors were associated with surgical candidacy and surgical utilization. RESULTS:A total of 353 patients were seen during the period reviewed, of which 144 had complete medical records. Our cohort included 90 nonsurgical candidates, 25 surgical candidates who declined surgery, and 29 patients who underwent surgery. In multivariable analysis, factors negatively associated with surgical candidacy were age, a history of smoking, and osteoporosis, where those positively associated with surgical candidacy were reports of spine-specific pain, higher Charlson Comorbidity Index, pain medication use, number of neurological symptoms, and being myelopathic. Factors positively associated with surgical utilization included proportion of all complaints that were neurological in nature, being myelopathic, higher Charlson Comorbidity Index, and report of pain as chronic, whereas being osteoporotic was negatively associated with surgical use. A receiver operating curve constructed for these models produced c-statistics of 0.75 and 0.80, respectively. CONCLUSIONS:Our results suggest that the results of standard clinic intake questions, such as review of systems, medical history, and chief complaints, may be predictive of surgical candidacy before evaluation by a surgeon. The present pilot study suggests a preliminary algorithm that can be further validated and expanded upon to help decide on optimal patient referrals to spine surgery specialists.

OBJECTIVES/OBJECTIVE:Determine significant associations between patient frailty status and odontoid fractures across common traumatic mechanisms of injuries (MOI) in the elderly. DESIGN/METHODS:Retrospective review. SETTING/METHODS:Single, academic-affiliated hospital with full surgical servicesPatients/Participants: Patients >65 years old with traumatic odontoid fracture were included. INTERVENTION/METHODS:Non-operative management (soft/hard collar, halo, traction tongs, minerva) and/or operative fixation. MAIN OUTCOME MEASUREMENTS/METHODS:mFI, MOI, concurrent injuries, inpatient LOS, reoperation and mortality rates. RESULTS:70 patients were included (80.6±8.5yrs, 60%F, 88% European, 10% Maori/Pacific, 1.4% Asian, CCI 5.3± 2.2, mFI 0.21±0.15). The most common MOIs were Falls (74.3%), high speed MVAs (17.1%), low speed MVAs (5.7%), and pedestrian vs car (2.9%). Patients with traumatic falls exhibited significantly higher mFI scores (0.25) compared to low speed MVAs (0.16), high speed MVAs (0.08), and pedestrian vs car (0.01) (p=0.003). Twenty-seven patients with odontoid fractures were Frail, 33 were Pre-frail, and 10 were Robust. 92% of Frail patients had traumatic fall as their MOI, as opposed to 73% of Pre-frail and 30% of Robust patients (p<0.001). Pre-frail and Frail patients were 4.3 times more likely than Robust patients to present with odontoid fractures via traumatic fall (OR: 4.33 [1.47-12.75], p=0.008), and frailty increased likelihood of reoperation (OR: 4.2 [1.2-14.75], p=0.025) and extended LOS (OR: 5.71 [1.05-10.37], p=0.017). Frail patients had the highest 30-day (p=0.017) and 1-year mortality (p<0.001) compared to other groups. CONCLUSION/CONCLUSIONS:Patients with traumatic odontoid fracture from falls were significantly more frail in comparison to any other MOI, with worse short and long-term outcomes. LEVEL OF EVIDENCE/METHODS:Level III Retrospective Cohort Study.