The effect of C2 screw type on perioperative outcomes and long-term stability after C2-T2 posterior cervical decompression and fusion.

PURPOSE: To determine if C2 pedicle versus pars screw type predicts change in fusion status, C2 screw loosening, cervical alignment, and patient-reported outcomes measures (PROMs) after C2-T2 posterior cervical decompression and fusion (PDCF). METHODS: All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy between 2013-2020 were retrospectively identified. Patients were dichotomized by C2 screw type into bilateral C2 pedicle and bilateral C2 pars screw groups. Preoperative and short- and long-term postoperative radiographic outcomes and PROMs were collected. Univariate and multivariate analysis compared patient factors, fusion status, radiographic measures, and PROMs across groups. RESULTS: A total of 159 patients met the inclusion/exclusion criteria (76 bilateral pedicle screws, 83 bilateral pars screws). Patients in the C2 pars relative to C2 pedicle screw group were on average more likely to have bone morphogenic protein (p = 0.001) and four-millimeter diameter rods utilized intraoperatively (p = 0.033). There were no significant differences in total construct and C2-3 fusion rate, C2 screw loosening, or complication and revision rates between C2 screw groups in univariate and regression analysis. Changes in C2 tilt, C2-3 segmental lordosis, C0-2 Cobb angle, proximal junctional kyphosis, atlanto-dens interval, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 screw type. CONCLUSION: There were no significant differences in fusion status, hardware complications, and radiographic and clinical outcomes based on C2 screw type following C2-T2 PCDF. Accordingly, intraoperative usage criteria can be flexible based on patient vertebral artery positioning and surgeon comfort level.

Unilateral versus bilateral pedicle screw fixation with anterior lumbar interbody fusion: a comparison of postoperative outcomes.

PURPOSE: To determine of the impact of ALIF with minimally invasive unilateral pedicle screw fixation (UPSF) versus bilateral pedicle screw fixation (BPSF) on perioperative outcomes, radiographic outcomes, and the rates of fusion, subsidence, and adjacent segment stenosis. METHODS: All adult patients who underwent one-level ALIF with UPSF or BPSF at an academic institution between 2015 and 2022 were retrospectively identified. Postoperative outcomes including length of hospital stay (LOS), wound complications, readmissions, and revisions were determined. The rates of fusion, screw loosening, adjacent segment stenosis, and subsidence were assessed on one-year postoperative CT. Lumbar alignment including lumbar lordosis, L4-S1 lordosis, regional lordosis, pelvic tilt, pelvic incidence, and sacral slope were assessed on standing x-rays at preoperative, immediate postoperative, and final postoperative follow-up. Univariate and multivariate analysis compared outcomes across posterior fixation groups. RESULTS: A total of 60 patients were included (27 UPSF, 33 BPSF). Patients with UPSF were significantly younger (p = 0.011). Operative time was significantly greater in the BPSF group in univariate (p < 0.001) and multivariate analysis (ß=104.1, p < 0.001). Intraoperative blood loss, LOS, lordosis, pelvic parameters, fusion rate, subsidence, screw loosening, adjacent segment stenosis, and revision rate did not differ significantly between fixation groups. Though sacral slope (p = 0.037) was significantly greater in the BPSF group, fixation type was not a significant predictor on regression. CONCLUSIONS: ALIF with UPSF relative to BPSF predicted decreased operative time but was not a significant predictor of postoperative outcomes. ALIF with UPSF can be considered to increase operative efficiency without compromising construct stability.

C1-C2 Posterior Screw-Rod Fixation.

Multiple approaches for instrumentation of the upper cervical spine have evolved to treat atlantoaxial instability which, until the 20th century, was largely considered to be inoperable and managed nonsurgically with immobilization. Surgeons set out to provide safe and effective approaches in a clearly dangerous and technically complex anatomic region. It is important to provide a historical analysis of the evolution of techniques that have shaped C1-C2 instrumentation, and how the diligent efforts of surgeons to improve the biomechanical stability and fusion rates of their constructs eventually led to the prevailing Harms technique. This technique is explored by describing its surgical steps, alternative techniques, and associated outcomes. For successful instrumentation of the atlantoaxial joint, a comprehensive understanding of spinal biomechanics, surgical techniques, and anatomic variations is imperative for surgeons to develop a tailored plan for each patient's individual pathology and anatomy.

Cervical Paraspinal Muscle Fatty Degeneration Is Not Associated with Muscle Cross-sectional Area: Qualitative Assessment Is Preferable for Cervical Sarcopenia.

BACKGROUND: Sarcopenia, defined as decreased skeletal mass, is an independent marker of frailty that is not accounted for by other risk-stratification methods. Recent studies have demonstrated a clear association between paraspinal sarcopenia and worse patient-reported outcomes and complications after spine surgery. Currently, sarcopenia is characterized according to either a quantitative assessment of the paraspinal cross-sectional area or a qualitative analysis of paraspinal fatty infiltration on MRI. No studies have investigated whether the cervical paraspinal cross-sectional area correlates with fatty infiltration of the cervical paraspinal muscles on advanced imaging. QUESTION/PURPOSE: Do patients undergoing anterior cervical discectomy and fusion (ACDF) with increasing paraspinal fatty degeneration on advanced imaging also demonstrate decreased cervical paraspinal cross-sectional area? METHODS: Between 2011 and 2017, 98 patients were prospectively enrolled in a database of patients undergoing one- to three-level ACDF for degenerative conditions at a single institution. To be eligible for this prospective study, patients were required to undergo an MRI before surgery, be older than 18 years, and have no previous history of cervical spine surgery. Two independent reviewers, both surgeons not involved in the patients' care and who were blinded to the clinical outcomes, retrospectively assessed the paraspinal cross-sectional area and Goutallier classification of the right-sided paraspinal muscle complex. We then compared the patients' Goutallier grades with their paraspinal cross-sectional area measurements. We identified 98 patients for inclusion. Using the Fuchs modification of the Goutallier classification, we classified the fatty degeneration of 41 patients as normal (Goutallier Grades 0 to 1), that of 47 patients as moderate (Grade 2), and that of 10 patients as severe (Grades 3 to 4). We used ANOVA to compare all means between groups. RESULTS: There was no difference in the mean paraspinal cross-sectional area of the obliquus capitus inferior (normal 295 ± 81 mm2; moderate 317 ± 104 mm2; severe 300 ± 79 mm2; p = 0.51), multifidus (normal 146 ± 59 mm2; moderate 170 ± 70 mm2; severe 192 ± 107 mm2; p = 0.11), or sternocleidomastoid (normal 483 ± 150 mm2; moderate 468 ± 149 mm2; severe 458 ± 183 mm2; p = 0.85) among patients with mild, moderate, and severe fatty infiltration based on Goutallier grading. There was a slightly greater longus colli cross-sectional area in the moderate and severe fatty infiltration groups (74 ± 22 mm2 and 66 ± 18 mm2, respectively) than in the normal group (63 ± 15 mm2; p = 0.03). CONCLUSION: Because our study demonstrates minimal association between paraspinal cross-sectional area and fatty infiltration of the cervical paraspinals, we recommend that physicians use the proven qualitative assessment of paraspinal fatty infiltration during preoperative evaluation of patients who are candidates for ACDF. Future studies investigating the relationship between cervical paraspinal cross-sectional area and patient-reported outcomes after ACDF are necessary to lend greater strength to this recommendation. LEVEL OF EVIDENCE: Level III, diagnostic study.

Regional improvements in lumbosacropelvic Hounsfield units following teriparatide treatment.

OBJECTIVE: Opportunistic Hounsfield unit (HU) determination from CT imaging has been increasingly used to estimate bone mineral density (BMD) in conjunction with assessments from dual energy x-ray absorptiometry (DXA). The authors sought to compare the effect of teriparatide on HUs across different regions in the pelvis, sacrum, and lumbar spine, as a surrogate measure for the effects of teriparatide on lumbosacropelvic instrumentation. METHODS: A single-institution retrospective review of patients who had been treated with at least 6 months of teriparatide was performed. All patients had at least baseline DXA as well as pre- and post-teriparatide CT imaging. HUs were measured in the pedicle, lamina, and vertebral body of the lumbar spine, in the sciatic notch, and at the S1 and S2 levels at three different points (ilium, sacral body, and sacral ala). RESULTS: Forty patients with an average age of 67 years underwent a mean of 20 months of teriparatide therapy. Mean HUs of the lumbar lamina, pedicles, and vertebral body were significantly different from each other before teriparatide treatment: 343 ± 114, 219 ± 89.2, and 111 ± 48.1, respectively (p < 0.001). Mean HUs at the S1 level for the ilium, sacral ala, and sacral body were also significantly different from each other: 124 ± 90.1, -10.7 ± 61.9, and 99.1 ± 72.1, respectively (p < 0.001). The mean HUs at the S2 level for the ilium and sacral body were not significantly different from each other, although the mean HU at the sacral ala (-11.9 ± 52.6) was significantly lower than those at the ilium and sacral body (p = 0.003 and 0.006, respectively). HU improvement occurred in most regions following teriparatide treatment. In the lumbar spine, the mean lamina HU increased from 343 to 400 (p < 0.001), the mean pedicle HU increased from 219 to 242 (p = 0.04), and the mean vertebral body HU increased from 111 to 134 (p < 0.001). There were also significant increases in the S1 sacral body (99.1 to 130, p < 0.05), S1 ilium (124 vs 165, p = 0.01), S1 sacral ala (-10.7 vs 3.68, p = 0.04), and S2 sacral body (168 vs 189, p < 0.05). CONCLUSIONS: There was significant regional variation in lumbar and sacropelvic HUs, with most regions significantly increasing following teriparatide treatment. The sacropelvic area had lower HU values than the lumbar spine, more regional variation, and a higher degree of correlation with BMD as measured on DXA. While teriparatide treatment resulted in HUs > 110 in the majority of the lumbosacral spine, the HUs in the sacral ala remained suggestive of severe osteoporosis, which may limit the effectiveness of fixation in this region.

Osteoporosis in spine surgery patients: what is the best way to diagnose osteoporosis in this population?

OBJECTIVE: The goal of this study was to compare different recognized definitions of osteoporosis in patients with degenerative lumbar spine pathology undergoing elective spinal fusion surgery to determine which patient population should be considered for preoperative optimization. METHODS: A retrospective review of patients in whom lumbar spine surgery was planned at 2 academic medical centers was performed, and the rate of osteoporosis was compared based on different recognized definitions. Assessments were made based on dual-energy x-ray absorptiometry (DXA), CT Hounsfield units (HU), trabecular bone score (TBS), and fracture risk assessment tool (FRAX). The rate of osteoporosis was compared based on different definitions: 1) the WHO definition (T-score ≤ -2.5) at total hip or spine; 2) CT HU of < 110; 3) National Bone Health Alliance (NBHA) guidelines; and 4) "expanded spine" criteria, which includes patients meeting NBHA criteria and/or HU < 110, and/or "degraded" TBS in the setting of an osteopenic T-score. Inclusion criteria were adult patients with a DXA scan of the total hip and/or spine performed within 1 year and a lumbar spine CT scan within 6 months of the physician visit. RESULTS: Two hundred forty-four patients were included. The mean age was 68.3 years, with 70.5% female, 96.7% Caucasian, and the mean BMI was 28.8. Fracture history was reported in 53.8% of patients. The proportion of patients identified with osteoporosis on DXA, HUs, NBHA guidelines, and the authors' proposed "expanded spine" criteria was 25.4%, 36.5%, 75%, and 81.9%, respectively. Of the patients not identified with osteoporosis on DXA, 31.3% had osteoporosis based on HU, 55.1% had osteoporosis with NBHA, and 70.4% had osteoporosis with expanded spine criteria (p < 0.05), with poor correlations among the different assessment tools. CONCLUSIONS: Limitations in the use of DXA T-scores alone to diagnose osteoporosis in patients with lumbar spondylosis has prompted interest in additional methods of evaluating bone health in the spine, such as CT HU, TBS, and FRAX, to inform guidelines that aim to reduce fracture risk. However, no current osteoporosis assessment was developed with a focus on improving outcomes in spinal surgery. Therefore, the authors propose an expanded spine definition for osteoporosis to identify a more comprehensive cohort of patients with potential poor bone health who could be considered for preoperative optimization, although further study is needed to validate these results in terms of clinical outcomes.

Correction to: Is the new ASNM intraoperative neuromonitoring supervision "guideline" a trustworthy guideline? A commentary.

The article Is the new ASNM intraoperative neuromonitoring supervision "guideline" a trustworthy guideline? A commentary, written by Stanley A. Skinner, Elif Ilgaz Aydinlar, Lawrence F. Borges, Bob S. Carter, Bradford L. Currier, Vedran Deletis, Charles Dong, John Paul Dormans, Gea Drost, Isabel Fernandez­Conejero, E. Matthew Hoffman, Robert N. Holdefer, Paulo Andre Teixeira Kimaid, Antoun Koht, Karl F. Kothbauer, David B. MacDonald, John J. McAuliffe III, David E. Morledge, Susan H. Morris, Jonathan Norton, Klaus Novak, Kyung Seok Park, Joseph H. Perra, Julian Prell, David M. Rippe, Francesco Sala, Daniel M. Schwartz, Martín J. Segura, Kathleen Seidel, Christoph Seubert, Mirela V. Simon, Francisco Soto, Jeffrey A. Strommen, Andrea Szelenyi, Armando Tello, Sedat Ulkatan, Javier Urriza and Marshall Wilkinson, was originally published electronically on the publisher's internet portal (currently SpringerLink) on 05 January 2019 without open access. With the author(s)' decision to opt for Open Choice the copyright of the article changed on 30 January 2019 to © The Author(s) 2019 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made. The original article has been corrected.

Does Intrawound Vancomycin Decrease Postoperative Surgical Site Infection in Spine Surgery: A Retrospective Case-control Study.

STUDY DESIGN: Retrospective Case-Control series. OBJECTIVE: The objective of this study is to define the overall postoperative rate of surgical site infection (SSI) in patients undergoing spine surgery and examine the effects of intrawound Vancomycin on postoperative infection rates. SUMMARY OF BACKGROUND DATA: Surgical site infections (SSI) account for 22% of all health care-associated infections. The use of intrawound Vancomycin in an attempt to reduce the incidence of postoperative SSI has not been sufficiently evaluated in the existing literature. METHODS: All spine surgeries (n=19,081) from our institution were reviewed from 2003 to 2013. All cases of verified SSI were identified from the database. Cases were then matched to controls in a 1:1 fashion based on age, gender, and date of surgery (+/-30 d). Patient demographics, comorbidities, estimated blood loss, duration of surgery, intrawound administration of Vancomycin, and smoking status were evaluated. RESULTS: At total of 316 cases of SSI after spine surgery were identified, representing an infection rate of 1.7%. The mean follow-up for cases and controls was 31.5 and 41.6 months, respectively. OR for intrawound Vancomycin was 0.44 (95% CI 0.23-0.88, P =0.019). OR for BMI greater than 30 was 1.63 (95% CI 1.04-2.56, P =0.03). CONCLUSIONS: In this large cohort of spine surgery patients, administration of intrawound Vancomycin was associated with a significant reduction in postoperative surgical site infections. Further studies are needed to determine appropriate dosing and application as well as long-term safety in spine surgery.

Surgical management of malignant melanotic nerve sheath tumors: an institutional experience and systematic review of the literature.

OBJECTIVE: Malignant melanotic nerve sheath tumors are rare tumors characterized by neoplastic melanin-producing Schwann cells. In this study, the authors report their institution's experience in treating spinal and peripheral malignant melanotic nerve sheath tumors and compare their results with the literature. METHODS: Data were collected from 8 patients who underwent surgical treatment for malignant melanotic nerve sheath tumors between 1996 and 2023 at Mayo Clinic and 63 patients from the literature. Time-to-event analyses were performed for the combined group of 71 cases to evaluate the risk of recurrence, metastasis, and death based on tumor location and type of treatment received. Unpaired 2-sample t-tests and Fisher's exact tests were used to determine statistical significance between groups. RESULTS: Between 1996 and 2023, 8 patients with malignant melanotic nerve sheath tumors underwent surgery at the authors' institution, while 63 patients were identified in the literature. The authors' patients and those in the literature had the same mean age at diagnosis (43 years). At the authors' institution, 5 patients (63%) experienced metastasis, 6 patients (75%) experienced long-term recurrence, and 5 patients (62.5%) died. In the literature, most patients (60.3%) were males, with a peak incidence between the 4th and 5th decades of life. Nineteen patients (31.1%) were diagnosed with Carney complex. Nerve root tumors accounted for most presentations (n = 39, 61.9%). Moreover, 24 patients (38.1%) had intradural lesions, with 54.2% (n = 13) being intramedullary and 45.8% (n = 11) extramedullary. Most patients underwent gross-total resection (GTR) (n = 41, 66.1%), followed by subtotal resection (STR) (n = 12, 19.4%), STR with radiation therapy (9.7%), and GTR with radiation therapy (4.8%). Sixteen patients (27.6%) experienced metastasis, 23 (39.7%) experienced recurrence, and 13 (22%) died. Kaplan-Meier analyses showed no significant differences among treatment approaches in terms of recurrence-free, metastasis-free, and overall survival (p > 0.05). Similar results were obtained when looking at the differences with respect to intradural versus nerve root location of the tumor (p > 0.05). CONCLUSIONS: Malignant melanotic nerve sheath tumors are rare tumors with a high potential for malignancy. They carry a dismal prognosis, with a pooled local recurrence rate of 42%, distant metastasis rate of 27%, and mortality rate of 26%. The findings from this study suggest a trend favoring the use of GTR alone or STR with radiation therapy over STR alone. Mortality was similar regardless, which highlights the need for the development of effective treatment options to improve survival in patients with melanotic schwannomas.

The Effect of C2 Muscular Exposure Technique on Radiographic and Clinical Outcomes After C2-T2 Posterior Cervical Fusion.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To determine whether the C2 exposure technique was a predictor of change in cervical alignment and patient-reported outcomes measures (PROMs) after posterior cervical decompression and fusion (PCDF) for degenerative indications. BACKGROUND: In PCDF handling of the C2 posterior paraspinal musculature during the operative approach varies by surgeon technique. To date, no studies have investigated whether maintenance of the upper cervical semispinalis cervicis attachments as compared with complete reflection of upper cervical paraspinal musculature from the posterior bony elements is associated with superior radiographic and clinical outcomes after PCDF. PATIENTS AND METHODS: All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy at multi-institutional academic centers between 2013 and 2020 were retrospectively identified. Patients were dichotomized by the C2 exposure technique into semispinalis preservation or midline muscular reflection groups. Preoperative and short and long-term postoperative radiographic outcomes (upper cervical alignment, global alignment, and fusion status) and PROMs (Visual Analog Scale-Neck, Neck Disability Index, and Short Form-12) were collected. Univariate analysis compared patient factors, radiographic measures, and PROMs across C2 exposure groups. RESULTS: A total of 129 patients met the inclusion/exclusion criteria (73 muscle preservation and 56 muscle reflection). Patients in the muscular preservation group were on average younger (P= 0.005) and more likely to have bone morphogenic protein (P< 0.001) and C2 pars screws (P= 0.006) used during surgery. Preoperative to postoperative changes in C2 slope, C2 tilt, C2-C3 segmental lordosis, C2-C3 listhesis, C0-C2 Cobb angle, proximal junctional kyphosis, ADI, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-C7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 exposure technique. Likewise, there were no significant differences in fusion status, C2-C3 pseudoarthrosis, C2 screw loosening, and complication and revision rates between C2 exposure groups. CONCLUSIONS: Preservation of C2 semispinalis attachments versus muscular reflection did not significantly impact cervical alignment, clinical outcomes, or proximal junction complications in long-segment PCDF. LEVEL OF EVIDENCE: Level III.

Transforaminal lumbar interbody fusion subsidence: computed tomography analysis of incidence, associated risk factors, and impact on outcomes.

OBJECTIVE: The aims of this study were to 1) define the incidence of transforaminal lumbar interbody fusion (TLIF) interbody subsidence; 2) determine the relative importance of preoperative and intraoperative patient- and instrumentation-specific risk factors predictive of postoperative subsidence using CT-based assessment; and 3) determine the impact of TLIF subsidence on postoperative complications and fusion rates. METHODS: All adult patients who underwent one- or two-level TLIF for lumbar degenerative conditions at a multi-institutional academic center between 2017 and 2019 were retrospectively identified. Patients with traumatic injury, infection, malignancy, previous fusion at the index level, combined anterior-posterior procedures, surgery with greater than two TLIF levels, or incomplete follow-up were excluded. Interbody subsidence at the superior and inferior endplates of each TLIF level was directly measured on the endplate-facing surface of both coronal and sagittal CT scans obtained greater than 6 months postoperatively. Patients were grouped based on the maximum subsidence at each operative level classified as mild, moderate, or severe based on previously documented < 2-mm, 2- to 4-mm, and ≥ 4-mm thresholds, respectively. Univariate and regression analyses compared patient demographics, medical comorbidities, preoperative bone quality, surgical factors including interbody cage parameters, and fusion and complication rates across subsidence groups. RESULTS: A total of 67 patients with 85 unique fusion levels met the inclusion and exclusion criteria. Overall, 28% of levels exhibited moderate subsidence and 35% showed severe subsidence after TLIF with no significant difference in the superior and inferior endplate subsidence. Moderate (≥ 2-mm) and severe (≥ 4-mm) subsidence were significantly associated with decreases in cage surface area and Taillard index as well as interbody cages with polyetheretherketone (PEEK) material and sawtooth surface geometry. Severe subsidence was also significantly associated with taller preoperative disc spaces, decreased vertebral Hounsfield units (HU), the absence of bone morphogenetic protein (BMP) use, and smooth cage surfaces. Regression analysis revealed decreases in Taillard index, cage surface area, and HU, and the absence of BMP use predicted subsidence. Severe subsidence was found to be a predictor of pseudarthrosis but was not significantly associated with revision surgery. CONCLUSIONS: Patient-level risk factors for TLIF subsidence included decreased HU and increased preoperative disc height. Intraoperative risk factors for TLIF subsidence were decreased cage surface area, PEEK cage material, bullet cages, posterior cage positioning, smooth cage surfaces, and sawtooth surface designs. Severe subsidence predicted TLIF pseudarthrosis; however, the causality of this relationship remains unclear.

Factors Related to Clinical Performance in Spine Surgery Fellowship: Can We Predict Success.

INTRODUCTION: The factors most important in the spine fellowship match may not ultimately correlate with quality of performance during fellowship. This study examined the spine fellow applicant metrics correlated with high application rank compared with the metrics associated with the strongest clinical performance during fellowship. METHODS: Spine fellow applications at three academic institutions were retrieved from the San Francisco Match database (first available to 2021) and deidentified for application review. Application metrics pertaining to research, academics, education, extracurriculars, leadership, examinations, career interests, and letter of recommendations were extracted. Attending spine surgeons involved in spine fellow selection at their institutions were sent a survey to rank (1) fellow applicants based on their perceived candidacy and (2) the strength of performance of their previous fellows. Pearson correlation assessed the associations of application metrics with theoretical fellow rank and actual performance. RESULTS: A total of 37 spine fellow applications were included (Institution A: 15, Institution B: 12, Institution C: 10), rated by 14 spine surgeons (Institution A: 6, Institution B: 4, Institution C: 4). Theoretical fellow rank demonstrated a moderate positive association with overall research, residency program rank, recommendation writer H-index, US Medical Licensing Examination (USMLE) scores, and journal reviewer positions. Actual fellow performance demonstrated a moderate positive association with residency program rank, recommendation writer H-index, USMLE scores, and journal reviewer positions. Linear regressions identified journal reviewer positions (ß = 1.73, P = 0.002), Step 1 (ß = 0.09, P = 0.010) and Step 3 (ß = 0.10, P = 0.002) scores, recommendation writer H-index (ß = 0.06, P = 0.029, and ß = 0.07, P = 0.006), and overall research (ß = 0.01, P = 0.005) as predictors of theoretical rank. Recommendation writer H-index (ß = 0.21, P = 0.030) and Alpha Omega Alpha achievement (ß = 6.88, P = 0.021) predicted actual performance. CONCLUSION: Residency program reputation, USMLE scores, and a recommendation from an established spine surgeon were important in application review and performance during fellowship. Research productivity, although important during application review, was not predictive of fellow performance. LEVEL OF EVIDENCE: III. STUDY DESIGN: Cohort Study.

Defining the value of spine care.

The increased cost and frequency of spine-related procedures, expanding indications, and regional variation in care has led to a shift toward delivery of value-based spine care. In this model, payers show preference for interventions and treatments with proven value and incentivize providers who use such interventions and demonstrate value in their practices. Thus, spine care providers must understand how to determine the value of interventions and treatments. Determining value (ie, cost and quality of care, measured over time) can be challenging in the setting of spine care. Data collection and reporting are complicated by variation in diagnostic coding and surgical techniques. Typically, outcomes in spine care are based on subjective patient-reported measures that are influenced by concomitant orthopaedic, medical, and psychological disease. Health utility is a preferable measure of quality that can be converted into quality-adjusted life years and used in cost-effectiveness analysis. Although no standard currently exists, estimates of cost should include both direct and indirect costs of care over an adequate time horizon.

Risk Factors for Allograft Subsidence Following Anterior Cervical Discectomy and Fusion.

OBJECTIVE: The purpose this study was to precisely characterize patterns of allograft subsidence following anterior cervical discectomy and fusion (ACDF) utilizing computed tomography scans, determine risk factors for cervical allograft subsidence, and investigate the impact of subsidence on pseudarthrosis rates. METHODS: We performed a retrospective review of patients undergoing 1-to 3-level ACDF utilizing allograft interbodies with anterior plating between 2011 and 2019. Subsidence measurements were performed by 2 independent reviewers on computed tomography scans obtained 6 months postoperatively. Subsidence was then classified as mild if subsidence into the inferior and superior endplates were both ≤2 mm, moderate if the worst subsidence into the inferior- or superior endplate was between 2 and 4 mm, or severe if the worst subsidence into the inferior- or superior endplate was ≥4 mm. Multivariate analysis was performed to identify risk factors for the development of subsidence. RESULTS: We identified 98 patients (152 levels) for inclusion. A total of 73 levels demonstrated mild subsidence (≤2 mm), 61 demonstrated moderate subsidence (2-4 mm), and 18 demonstrated severe subsidence (≥4 mm). On multivariate analysis, risk factors for severe subsidence included excessive vertebral endplate resection and lower screw tip to vertebral body height ratio. Severe subsidence was associated with an increased rate of pseudarthrosis (94.1% vs. 13.6%) without an associated increase in reoperation rate. CONCLUSIONS: Following ACDF with allograft interbodies, 50% of interbodies will subside >2 mm and 10% of interbodies will subside >4 mm. Risk factors for severe subsidence should be mitigated to decrease the risk of pseudarthrosis.

Semispinalis Cervicis Sarcopenia is Associated With Worsening Cervical Sagittal Balance and Junctional Alignment Following Posterior Cervical Fusion for Myelopathy.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The present study is the first to investigate whether cervical paraspinal sarcopenia is associated with cervicothoracic sagittal alignment parameters after posterior cervical fusion (PCF). SUMMARY OF BACKGROUND DATA: Few studies have investigated the association between sarcopenia and postoperative outcomes after cervical spine surgery. METHODS: We retrospectively reviewed patients undergoing PCF from C2-T2 at a single institution between the years 2017-2020. Two independent reviewers utilized axial cuts of T2-weighted magnetic resonance imaging sequences to perform Goutallier classification of the bilateral semispinalis cervicis (SSC) muscles. Cervical sagittal alignment parameters were compared between subgroups based upon severity of SSC sarcopenia. RESULTS: We identified 61 patients for inclusion in this study, including 19 patients with mild SSC sarcopenia and 42 patients with moderate or severe SSC sarcopenia. The moderate-severe sarcopenia subgroup demonstrated a significantly larger change in C2-C7 sagittal vertical axis (+6.8 mm) from the 3-month to 1-year postoperative follow-up in comparison to the mild sarcopenia subgroup (-2.0 mm; P =0.02). The subgroup of patients with moderate-severe sarcopenia also demonstrated an increase in T1-T4 kyphosis (10.9-14.2, P =0.007), T1 slope (28.2-32.4, P =0.003), and C2 slope (24.1-27.3, P =0.05) from 3-month to 1-year postoperatively and a significant decrease in C1-occiput distance (6.3-4.1, P =0.002) during this same interval. CONCLUSIONS: In a uniform cohort of patients undergoing PCF from C2-T2, SSC sarcopenia was associated with worsening cervicothoracic alignment from 3-month to 1-year postoperatively.

Paraspinal Sarcopenia is Associated With Worse Patient-Reported Outcomes Following Laminoplasty for Degenerative Cervical Myelopathy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The present study is the first to assess the impact of paraspinal sarcopenia on patient-reported outcome measures (PROMs) following cervical laminoplasty. BACKGROUND: While the impact of sarcopenia on PROMs following lumbar spine surgery is well-established, the impact of sarcopenia on PROMs following laminoplasty has not been investigated. METHODS: We performed a retrospective review of patients undergoing laminoplasty from C4-6 at a single institution between 2010 and 2021. Two independent reviewers utilized axial cuts of T2-weighted magnetic resonance imaging sequences to assess fatty infiltration of the bilateral transversospinales muscle group at the C5-6 level and classify patients according to the Fuchs Modification of the Goutalier grading system. PROMs were then compared between subgroups. RESULTS: We identified 114 patients for inclusion in this study, including 35 patients with mild sarcopenia, 49 patients with moderate sarcopenia, and 30 patients with severe sarcopenia. There were no differences in preoperative PROMs between subgroups. Mean postoperative neck disability index scores were lower in the mild and moderate sarcopenia subgroups (6.2 and 9.1, respectively) than in the severe sarcopenia subgroup (12.9, P =0.01). Patients with mild sarcopenia were nearly twice as likely to achieve minimal clinically important difference (88.6 vs. 53.5%; P <0.001) and six times as likely to achieve SCB (82.9 vs. 13.3%; P =0.006) compared with patients with severe sarcopenia. A higher percentage of patients with severe sarcopenia reported postoperative worsening of their neck disability index (13 patients, 43.3%; P =0.002) and Visual Analog Scale Arm scores (10 patients, 33.3%; P =0.03). CONCLUSION: Patients with severe paraspinal sarcopenia demonstrate less improvement in neck disability and pain postoperatively and are more likely to report worsening PROMs following laminoplasty. LEVEL OF EVIDENCE: 3.

Is Severe Neck Pain a Contraindication to Performing Laminoplasty in Patients With Cervical Spondylotic Myelopathy?

STUDY DESIGN: Retrospective review. OBJECTIVE: The purpose of this study was to investigate the surgical outcomes in a cohort of patients with severe preoperative axial neck pain undergoing laminoplasty for cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA: No study has investigated whether patients with severe axial symptoms may achieve satisfactory neck pain and disability outcomes after laminoplasty. METHODS: We performed a retrospective review of 91 patients undergoing C4-6 laminoplasty for CSM at a single academic institution between 2010 and 2021. Patient-reported outcome measures (PROMs), including Neck Disability Index (NDI), visual analog scale (VAS) Neck, and VAS Arm, were recorded preoperatively and at 6 months and 1 year postoperatively. Patients were stratified as having mild pain if VAS neck was 0-3, moderate pain if 4-6, and severe pain if 7-10. PROMs were then compared between subgroups at all the perioperative time points. RESULTS: Both the moderate and severe neck pain subgroups demonstrated a substantial improvement in VAS neck from preoperative to 6 months postoperatively (-3.1±2.2 vs. -5.6±2.8, respectively; P <0.001), and these improvements were maintained at 1 year postoperatively. There was no difference in VAS neck between subgroups at either the 6-month or 1-year postoperative time points. Despite the substantially higher mean NDI in the moderate and severe neck pain subgroups preoperatively, there was no difference in NDI at 6 months or 1 year postoperatively ( P =0.99). There were no differences between subgroups in the degree of cord compression, severity of multifidus sarcopenia, sagittal alignment, or complications. CONCLUSIONS: Patients with moderate and severe preoperative neck pain undergoing laminoplasty achieved equivalent PROMs at 6 months and 1 year as patients with mild preoperative neck pain. The results of this study highlight the multifactorial nature of neck pain in these patients and indicate that severe axial symptoms are not an absolute contraindication to performing laminoplasty in well-aligned patients with CSM.

Titanium Cervical Cage Subsidence: Postoperative Computed Tomography Analysis Defining Incidence and Associated Risk Factors.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Substantial variability in both the measurement and classification of subsidence limits the strength of conclusions that can be drawn from previous studies. The purpose of this study was to precisely characterize patterns of cervical cage subsidence utilizing computed tomography (CT) scans, determine risk factors for cervical cage subsidence, and investigate the impact of subsidence on pseudarthrosis rates. METHODS: We performed a retrospective review of patients who underwent one- to three-levels of anterior cervical discectomy and fusion (ACDF) utilizing titanium interbodies with anterior plating between the years 2018 and 2020. Subsidence measurements were performed by two independent reviewers on CT scans obtained 6 months postoperatively. Subsidence was then classified as mild if subsidence into the inferior and superior endplate were both ≤2 mm, moderate if the worst subsidence into the inferior or superior endplate was between 2 to 4 mm, or severe if the worst subsidence into the inferior or superior endplate was ≥4 mm. RESULTS: A total of 51 patients (100 levels) were included in this study. A total of 48 levels demonstrated mild subsidence (≤2 mm), 38 demonstrated moderate subsidence (2-4 mm), and 14 demonstrated severe subsidence (≥4 mm). Risk factors for severe subsidence included male gender, multilevel constructs, greater mean vertebral height loss, increased cage height, lower Taillard index, and lower screw tip to vertebral body height ratio. Severe subsidence was not associated with an increased rate of pseudarthrosis. CONCLUSION: Following ACDF with titanium cervical cages, subsidence is an anticipated postoperative occurrence and is not associated with an increased risk of pseudarthrosis.

Cervical myelopathy in a patient with Klippel-Feil syndrome treated with a patient-specific custom cervical spine locking plate.

INTRODUCTION: Klippel-Feil Syndrome is the congenital fusion of at least two cervical vertebrae. Often asymptomatic, though in rare cases it may lead to severe cervical spine deformity and neurologic injury. CASE PRESENTATION: We report a case of a 48-year-old woman with a history of Klippel-Feil Syndrome and congenital scoliosis who developed progressive cervical myelopathy. She was surgically treated with anterior C5 corpectomy and arthrodesis. Pre-operative evaluation was facilitated by 3D printed models. The surgical decompression and spinal reconstruction was completed with the use of a patient-specific, custom-made cervical spine locking plate. DISCUSSION: Pre-operative evaluation with 3D printing technology was useful in understanding the patient's complex curve pattern and in designing a patient specific implant. Custom designed implant is a reasonable option to treat cervical myelopathy associated with complex cervical deformity.