- Email: [email protected]
Friday, September 28, 2018 10:30 AM–12:00 PM abstracts: complications of cervical spine surgery
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The Spine Journal 18 (2018) S70 S128
obstruction 22.8% versus 14.1% (OR=1.799, p<.001) and bronchitis 9.2% versus 6.2% (OR=1.532, p=.008). CONCLUSIONS: Prior diagnosis of OSA within 1 year prior to patients undergoing one- or two-level cervical fusion is associated with greater rates of postoperative pulmonary complications within three months following surgery. Patients with OSA who underwent ACDF were at a greater risk of developing pulmonary complications than patients with OSA who underwent PCF. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2018.06.425
161. Incidence of postoperative stroke after anterior cervical discectomy and fusion in patients who have carotid stenosis Jared M. Newman, MD1, Morad Chughtai, MD2, George A. Beyer, MS1, Neil V. Shah, MD, MS1, Daniel P. Murray, BA1, Douglas A. Hollern, MD1, Louis M. Day, MD3, Rohan Desai, MD1, Bassel G. Diebo, MD3, Hiroyuki Yoshihara, MD, PhD1, Carl B. Paulino, MD1; 1 SUNY Downstate Medical Center, Brooklyn, NY, USA; 2 Cleveland, OH, USA; 3 Department of Orthopaedic Surgery, SUNY Downstate Medical Center, Brooklyn, NY, USA BACKGROUND CONTEXT: Anterior cervical discectomy and fusion (ACDF) is a procedure used to treat cervical myelopathy and radiculopathy. During the surgical approach, the sternocleidomastoid muscle and the carotid sheath are retracted laterally. Complications related to compression and retraction of the artery is infrequent. However, to our knowledge, there have been no studies that have evaluated carotid artery retraction and the development of a postoperative stroke in patients who have carotid artery stenosis. PURPOSE: The purpose of this study was to determine the incidence of postoperative strokes after ACDF in patients with carotid artery stenosis. STUDY DESIGN/SETTING: This study utilized the Statewide Planning and Research Cooperative System (SPARCS) database from 2009 to 2013. PATIENT SAMPLE: Patients who underwent ACDF between 2009 and 2013. Patients less than age 18 years and patients who had a previous history of a stroke that predated the ACDF were excluded. OUTCOME MEASURES: Primary outcome was the incidence of postoperative stroke after ACDF in patients with and without carotid artery stenosis. Secondary outcomes included other postoperative complications, lengths of stay (LOS), and total hospital charges. METHODS: Patient demographics included age, sex, race, insurance provider, Charlson/Deyo scores, and total hospital charges for each visit. Using the ACDF cohort, patients who had a preoperative diagnosis of carotid stenosis were identified, and were propensity score matched in a 1:1 ratio to those without a diagnosis of carotid stenosis based on age, sex, and Charlson/Deyo scores. We evaluated postoperative complications, including the incidence of a postoperative stroke. There were 61 patients in the carotid stenosis cohort and 61 patients without carotid stenosis. In terms of the demographics, compared to the patients without carotid stenosis, the carotid stenosis cohort was older (68 vs. 60 years, p<.001); however, none of the other demographics were significantly different. RESULTS: The incidence of postoperative stroke in the carotid artery stenosis cohort was significantly higher compared to those without carotid artery stenosis (6.6 vs. 0%, p<.042). Moreover, in terms of the other postoperative complications, compared to patients without carotid artery stenosis, those with carotid artery stenosis had a higher rate of acute renal failure (27.9 vs. 4.9%, p=.01), sepsis (18 vs. 4.9%, p=.023), and blood transfusion (39.3 vs. 13.1%, p=.001). Furthermore, compared to those without carotid artery stenosis, the carotid artery stenosis patients had a slightly shorter LOS (4.8 vs. 5.8 days, p=.736) and higher total charges (58,568 vs. 50,025 USD, p=.561), but these were not statistically significant. CONCLUSIONS: Patients with carotid artery stenosis who underwent ACDF had a significantly greater incidence of developing a postoperative stroke, among other complications, compared to patients without carotid stenosis. These patients could potentially benefit from medical or surgical optimization of their carotid stenosis prior to undergoing ACDF.
FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2018.06.426
162. Urinary N-telopeptide can predict pseudarthrosis after anterior cervical decompression and fusion (ACDF): a prospective study Patrick S. Hill, MD1, Jingyan Yang, PhD1, Eric Feuchtbaum, MD, MBA1, Michael E. Steinhaus, MD1, Pooja Prabhakar, BA2, Virginie Lafage, PhD1, Brandon B. Carlson, MD, MPH3, Philip Saville, MD1, Todd J. Albert, MD1, Renaud Lafage, MSc1, Emily M. Stein, MD1, Han Jo Kim, MD1; 1 Hospital for Special Surgery, New York, NY, USA; 2 Dallas, TX, USA; 3 New York, NY, USA BACKGROUND CONTEXT: Anterior cervical decompression and fusion (ACDF) is one of the most successful and widely performed spine surgeries. Although high rates of fusion have been reported, there is a risk for pseudarthrosis. Urinary cross-linked n-telopeptide of type I collagen (uNTx), is an important marker of bone turnover and may prove useful as a predictor of fusion in pts undergoing ACDF. PURPOSE: The purpose of the present study was to examine the association of preop uNTx level and successful fusion after ACDF. STUDY DESIGN/SETTING: Prospective cohort study. PATIENT SAMPLE: Adult patients who underwent ACDF with allograft and plating technique. OUTCOME MEASURES: Fusion status was assessed using radiographic criteria published by Song et al. METHODS: Patients undergoing primary ACDF with allograft and plating technique from 2015 to 2017 by a single surgeon were consecutively enrolled and preop uNTx was measured. Revision cases, improperly timed uNTx collection, pts with a Cr>1.2 were excluded. Demographics, operative, laboratory and fusion data was assessed at 6 months, 1 year and 2 years. NDI and VAS outcome scores were compared between fusion and nonfusion groups. Regression analysis was performed to assess the association of preop uNTx and successful fusion. RESULTS: Of the 97 patients enrolled, 67 met inclusion criteria and were studied. Forty-one percent, 33%, 18% and 8% underwent one-, two-, threeand four-level ACDFs, respectively. Fusion rates were 37.3% at 6 months (n=67), 70.9% at 1 year (n=55) and 95.3% at 2 years (n=43). The preop uNTx was higher in the fusion group at 6mo (31 vs. 22, p<.01) and at 1 year. (30 vs. 21, p<.01). There was no difference at 2 years. No differences were identified in preop vitamin D or calcium levels. Smoking status, diabetes, corpectomy, immunomodulatory agents (including steroids) and number of fusion levels were not different between groups. Multivariate regression analysis demonstrated the uNTx is an independent predictor of fusion (OR 1.124, p<.01). All patients had an improvement in NDI (40 vs. 17) and VAS (6.6 vs. 2.0) with ACDF at 6 months. A total of 17 patients with pseudarthrosis at 1 year, two underwent posterior cervical fusion for symptoms. CONCLUSIONS: Urinary NTx was higher in patients with successful ACDF fusion compared to patients with radiographic pseudarthrosis at 6 months and 1 year. A linear relationship between uNTx levels and fusion was observed. Surgeons should consider measuring uNTx prior to cervical fusion procedures to identify patients at risk for pseudarthrosis. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2018.06.427
163. Sagittal alignment parameters associated with adjacent segment pathology after anterior cervical discectomy and fusion Philip Louie, MD1, Bryce Basques, MD, MHS2, Justin C. Paul, MD, PhD3, Arya G. Varthi, MD4, Michael T. Nolte, MD5, Tarush Khurana, BA6, Steven T. Heidt, BS7, Edward J. Goldberg, MD8, Howard S. An, MD9; 1 Rush University Medical Center, Chicago, IL, USA; 2 Yale School of Medicine, New Haven, CT, USA; 3 Danbury Orthopedics, Danbury, CT,
Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.
The Spine Journal 18 (2018) S70 S128 4
USA; Yale University School of Medicine, New Haven, CT, USA; 5 Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA; 6 Chicago, IL, USA; 7 Rush Medical College, Chicago, IL, USA; 8 Midwest Orthopedics at Rush, Chicago, IL, USA; 9 Rush University Medical Center, Department of Orthopedic Surgery, Chicago, IL, USA BACKGROUND CONTEXT: Changes in the cervical alignment from preoperative to postoperative may alter cervical spine mechanics, and increase the rate of early adjacent segment pathology. Correction and restoration of cervical sagittal alignment is crucial in achieving a successful result after an ACDF and potentially decreasing the risk of developing ASD. PURPOSE: We sought to evaluate the relationship between cervical spine sagittal alignment and adjacent segment disease (ASD) following anterior cervical discectomy and fusion (ACDF) as determined by radiographic and clinical outcomes. STUDY DESIGN/SETTING: Retrospective cohort series. PATIENT SAMPLE: Patients undergoing ACDF from 2008 to 2015 who developed radiographic signs of ASD(+) were identified and compared to a matched group of ACDF patients who did not develop radiographic evidence of ASD(−) for a period of at least 1 year. Patients were excluded from analysis if they were under 18 years of age at the time of surgery, had postoperative follow-up less than 12 months or had an ACDF for cervical spine fracture or infection. OUTCOME MEASURES: The number or location of levels fused was recorded and radiographs were reviewed preoperatively, immediately postoperative, and at final follow up. The sagittal parameters measured included change in C2-C7 lordosis, T1 angle, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, proximal and distal adjacent segment lordosis. Patient-reported outcomes were obtained in the form of Neck Disability Index (NDI) scores and Visual Analog Scales (VAS) scores for the neck and arm. Radiographic diagnosis of ASD was determined by the presence of new or enlarged osteophytes, endplate sclerosis, disc space narrowing >50%, and/or increased calcification of the anterior longitudinal ligament (ALL) as presented by previous published studies. METHODS: Radiographic diagnosis of ASD was determined by the presence of new or enlarged osteophytes, endplate sclerosis, disc space narrowing >50%, and/or increased calcification of the anterior longitudinal ligament (ALL) as presented by previous published studies. Baseline patient characteristics were compared using chi-squared analysis and independent sample t-tests for categorical and continuous data, respectively. Bivariate and multivariate regressions were subsequently used to compare clinical outcomes between procedure groups. Multivariate analyses controlled for differences in baseline patient characteristics. RESULTS: A total of 101 ASD(+) patients were identified having undergone ACDF from 2008 to 2015 and compared to 131 ASD(−). The ASD (−) were free of ASD for at least 1 year. The groups were similar with regard to demographic and surgical variables, but with a predominance of males in the ASD group 61.2% (p=.001). Rigid plates were used in 42% of all constructs and were more represented in the ASD(−) than ASD(+) group (48% vs. 33%, respectively, p=.017). The most common levels included in the fusion were C5-7 (28%). For all patients, preoperative lordosis was increased from 4.8§11.4° to 7.9§10.2° postoperatively and improved to 9.4§9.9° at final follow-up. Patients with greater kyphosis throughout the cervical spine at final follow-up had increased odds of developing ASD (OR 0.97 per degree, p=.040). Patients with greater preoperative kyphosis through the planned fusion segment had increased odds of ASD (OR 0.93 per degree, p=.003). Patients who lost lordosis through the fusion from initial postop to final follow-up had greater odds of developing ASD (OR 0.85 per degree, p<0.001). Patients who had greater change in preoperative to postoperative fusion segment lordosis were found to exhibit a greater risk of ASD (OR 1.06 per degree, p=0.019). The SVA and T1 slope angles did not change substantially from preoperative to postoperative and there were no differences between ASD groups. The mean postoperative and final proximal and distal segment lordosis was
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also not different between groups except for significantly less proximal adjacent segment lordosis in ASD patients at final follow-up (0.2§5.0 vs. 1.4§4.4; p=.026). There were no significant differences between preoperative, postoperative, or change in patient-reported outcome surveys in patients with or without signs of radiographic ASD. CONCLUSIONS: Patients with a greater preoperative cervical kyphosis and kyphosis through the proposed fusion segment may have greater odds of develeoping radiographic adjacent segment degeneration. Similarly, those that had a greater greater correction of cervical lordosis postoperatively, and those who loss lordosis at the fusion segment also presented with increased odds of developing adjacent segment degeneration. Our results suggest that preoperative and postoperative measures of cervical spine alignment, specifically related to C2-C7 and fusion segment lordosis, may predict the development of radiographic signs of adjacent level pathology following an ACDF. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2018.06.428
Friday, September 28, 2018 10:30 AM–12:00 PM Deformity: Technical Factors 164. Incidence, risk factors and the natural history of proximal junctional kyphosis: review of long-term surgical outcomes using hybrid fusion constructs for adolescent idiopathic scoliosis Andrew J. Pugely, MD1, Luca Labianca, MD, PhD2, Piyush Kalakoti, MD1, Pawin Gajaseni, MD2, Stuart L. Weinstein, MD2; 1 University of Iowa, Iowa City, IA, USA; 2 Iowa City, IA, USA BACKGROUND CONTEXT: Proximal junctional kyphosis (PJK) is an unsolved radiographic phenomenon after corrective spinal deformity surgery with a high, but variable reported incidence. While known to influence outcomes in adults, the long-term clinical significance and natural history in children has not been well defined. Identifying incidence, riskfactors and natural course of PJK based on several proposed definitions in the literature using a large cohort may aid in enhancing our understanding of the disease entity. PURPOSE: In a single-surgeon series of AIS patients undergoing deformity correction using hybrid hooks or screw constructs, the study attempted to identify potential risk factors associated with the long-term development of PJK. Additionally, the study also defines PJK incidence and highlights the natural course of PJK development in children based on commonly proposed definitions in the literature. STUDY DESIGN/SETTING: Retrospective, single-surgeon series with a minimum 2-year follow-up. PATIENT SAMPLE: Overall, 253 eligible AIS patients with complete information on the proximal junctional angle (PJA) who underwent spinal deformity fusion (PSF) surgery by a single surgeon (SLW) at the University of Iowa between 2006 and 2015 that met the minimal criteria of 2-year follow-up were included. OUTCOME MEASURES: The primary outcome was to assess incidence of PJK development form preoperative to postoperative measurements based on two commonly utilized definitions: Glattes et al that defines PJK as PJA> 10°, and Bridwell et al classification that defines the disease entity based on the critical PJA above 20°. Secondary outcome was to investigate factors associated with PJK development based on patient demographics, radiological indices and outcomes, and describe the natural course of PJK development in AIS patients undergoing deformity correction. METHODS: AIS patients aged between 9 and 18 years undergoing primary long-construct PSF (UIV T2-4) between 2006 and 2015 with a minimum 2 years’ follow-up were included. Proximal junctional kyphosis was defined as a change in the PJA, according to Glattes et al and Bridwell et al classification from preop to postop. The incidence of PJK was defined at
Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.
The Spine Journal 18 (2018) S70 S128
obstruction 22.8% versus 14.1% (OR=1.799, p<.001) and bronchitis 9.2% versus 6.2% (OR=1.532, p=.008). CONCLUSIONS: Prior diagnosis of OSA within 1 year prior to patients undergoing one- or two-level cervical fusion is associated with greater rates of postoperative pulmonary complications within three months following surgery. Patients with OSA who underwent ACDF were at a greater risk of developing pulmonary complications than patients with OSA who underwent PCF. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2018.06.425
161. Incidence of postoperative stroke after anterior cervical discectomy and fusion in patients who have carotid stenosis Jared M. Newman, MD1, Morad Chughtai, MD2, George A. Beyer, MS1, Neil V. Shah, MD, MS1, Daniel P. Murray, BA1, Douglas A. Hollern, MD1, Louis M. Day, MD3, Rohan Desai, MD1, Bassel G. Diebo, MD3, Hiroyuki Yoshihara, MD, PhD1, Carl B. Paulino, MD1; 1 SUNY Downstate Medical Center, Brooklyn, NY, USA; 2 Cleveland, OH, USA; 3 Department of Orthopaedic Surgery, SUNY Downstate Medical Center, Brooklyn, NY, USA BACKGROUND CONTEXT: Anterior cervical discectomy and fusion (ACDF) is a procedure used to treat cervical myelopathy and radiculopathy. During the surgical approach, the sternocleidomastoid muscle and the carotid sheath are retracted laterally. Complications related to compression and retraction of the artery is infrequent. However, to our knowledge, there have been no studies that have evaluated carotid artery retraction and the development of a postoperative stroke in patients who have carotid artery stenosis. PURPOSE: The purpose of this study was to determine the incidence of postoperative strokes after ACDF in patients with carotid artery stenosis. STUDY DESIGN/SETTING: This study utilized the Statewide Planning and Research Cooperative System (SPARCS) database from 2009 to 2013. PATIENT SAMPLE: Patients who underwent ACDF between 2009 and 2013. Patients less than age 18 years and patients who had a previous history of a stroke that predated the ACDF were excluded. OUTCOME MEASURES: Primary outcome was the incidence of postoperative stroke after ACDF in patients with and without carotid artery stenosis. Secondary outcomes included other postoperative complications, lengths of stay (LOS), and total hospital charges. METHODS: Patient demographics included age, sex, race, insurance provider, Charlson/Deyo scores, and total hospital charges for each visit. Using the ACDF cohort, patients who had a preoperative diagnosis of carotid stenosis were identified, and were propensity score matched in a 1:1 ratio to those without a diagnosis of carotid stenosis based on age, sex, and Charlson/Deyo scores. We evaluated postoperative complications, including the incidence of a postoperative stroke. There were 61 patients in the carotid stenosis cohort and 61 patients without carotid stenosis. In terms of the demographics, compared to the patients without carotid stenosis, the carotid stenosis cohort was older (68 vs. 60 years, p<.001); however, none of the other demographics were significantly different. RESULTS: The incidence of postoperative stroke in the carotid artery stenosis cohort was significantly higher compared to those without carotid artery stenosis (6.6 vs. 0%, p<.042). Moreover, in terms of the other postoperative complications, compared to patients without carotid artery stenosis, those with carotid artery stenosis had a higher rate of acute renal failure (27.9 vs. 4.9%, p=.01), sepsis (18 vs. 4.9%, p=.023), and blood transfusion (39.3 vs. 13.1%, p=.001). Furthermore, compared to those without carotid artery stenosis, the carotid artery stenosis patients had a slightly shorter LOS (4.8 vs. 5.8 days, p=.736) and higher total charges (58,568 vs. 50,025 USD, p=.561), but these were not statistically significant. CONCLUSIONS: Patients with carotid artery stenosis who underwent ACDF had a significantly greater incidence of developing a postoperative stroke, among other complications, compared to patients without carotid stenosis. These patients could potentially benefit from medical or surgical optimization of their carotid stenosis prior to undergoing ACDF.
FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2018.06.426
162. Urinary N-telopeptide can predict pseudarthrosis after anterior cervical decompression and fusion (ACDF): a prospective study Patrick S. Hill, MD1, Jingyan Yang, PhD1, Eric Feuchtbaum, MD, MBA1, Michael E. Steinhaus, MD1, Pooja Prabhakar, BA2, Virginie Lafage, PhD1, Brandon B. Carlson, MD, MPH3, Philip Saville, MD1, Todd J. Albert, MD1, Renaud Lafage, MSc1, Emily M. Stein, MD1, Han Jo Kim, MD1; 1 Hospital for Special Surgery, New York, NY, USA; 2 Dallas, TX, USA; 3 New York, NY, USA BACKGROUND CONTEXT: Anterior cervical decompression and fusion (ACDF) is one of the most successful and widely performed spine surgeries. Although high rates of fusion have been reported, there is a risk for pseudarthrosis. Urinary cross-linked n-telopeptide of type I collagen (uNTx), is an important marker of bone turnover and may prove useful as a predictor of fusion in pts undergoing ACDF. PURPOSE: The purpose of the present study was to examine the association of preop uNTx level and successful fusion after ACDF. STUDY DESIGN/SETTING: Prospective cohort study. PATIENT SAMPLE: Adult patients who underwent ACDF with allograft and plating technique. OUTCOME MEASURES: Fusion status was assessed using radiographic criteria published by Song et al. METHODS: Patients undergoing primary ACDF with allograft and plating technique from 2015 to 2017 by a single surgeon were consecutively enrolled and preop uNTx was measured. Revision cases, improperly timed uNTx collection, pts with a Cr>1.2 were excluded. Demographics, operative, laboratory and fusion data was assessed at 6 months, 1 year and 2 years. NDI and VAS outcome scores were compared between fusion and nonfusion groups. Regression analysis was performed to assess the association of preop uNTx and successful fusion. RESULTS: Of the 97 patients enrolled, 67 met inclusion criteria and were studied. Forty-one percent, 33%, 18% and 8% underwent one-, two-, threeand four-level ACDFs, respectively. Fusion rates were 37.3% at 6 months (n=67), 70.9% at 1 year (n=55) and 95.3% at 2 years (n=43). The preop uNTx was higher in the fusion group at 6mo (31 vs. 22, p<.01) and at 1 year. (30 vs. 21, p<.01). There was no difference at 2 years. No differences were identified in preop vitamin D or calcium levels. Smoking status, diabetes, corpectomy, immunomodulatory agents (including steroids) and number of fusion levels were not different between groups. Multivariate regression analysis demonstrated the uNTx is an independent predictor of fusion (OR 1.124, p<.01). All patients had an improvement in NDI (40 vs. 17) and VAS (6.6 vs. 2.0) with ACDF at 6 months. A total of 17 patients with pseudarthrosis at 1 year, two underwent posterior cervical fusion for symptoms. CONCLUSIONS: Urinary NTx was higher in patients with successful ACDF fusion compared to patients with radiographic pseudarthrosis at 6 months and 1 year. A linear relationship between uNTx levels and fusion was observed. Surgeons should consider measuring uNTx prior to cervical fusion procedures to identify patients at risk for pseudarthrosis. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2018.06.427
163. Sagittal alignment parameters associated with adjacent segment pathology after anterior cervical discectomy and fusion Philip Louie, MD1, Bryce Basques, MD, MHS2, Justin C. Paul, MD, PhD3, Arya G. Varthi, MD4, Michael T. Nolte, MD5, Tarush Khurana, BA6, Steven T. Heidt, BS7, Edward J. Goldberg, MD8, Howard S. An, MD9; 1 Rush University Medical Center, Chicago, IL, USA; 2 Yale School of Medicine, New Haven, CT, USA; 3 Danbury Orthopedics, Danbury, CT,
Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.
The Spine Journal 18 (2018) S70 S128 4
USA; Yale University School of Medicine, New Haven, CT, USA; 5 Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA; 6 Chicago, IL, USA; 7 Rush Medical College, Chicago, IL, USA; 8 Midwest Orthopedics at Rush, Chicago, IL, USA; 9 Rush University Medical Center, Department of Orthopedic Surgery, Chicago, IL, USA BACKGROUND CONTEXT: Changes in the cervical alignment from preoperative to postoperative may alter cervical spine mechanics, and increase the rate of early adjacent segment pathology. Correction and restoration of cervical sagittal alignment is crucial in achieving a successful result after an ACDF and potentially decreasing the risk of developing ASD. PURPOSE: We sought to evaluate the relationship between cervical spine sagittal alignment and adjacent segment disease (ASD) following anterior cervical discectomy and fusion (ACDF) as determined by radiographic and clinical outcomes. STUDY DESIGN/SETTING: Retrospective cohort series. PATIENT SAMPLE: Patients undergoing ACDF from 2008 to 2015 who developed radiographic signs of ASD(+) were identified and compared to a matched group of ACDF patients who did not develop radiographic evidence of ASD(−) for a period of at least 1 year. Patients were excluded from analysis if they were under 18 years of age at the time of surgery, had postoperative follow-up less than 12 months or had an ACDF for cervical spine fracture or infection. OUTCOME MEASURES: The number or location of levels fused was recorded and radiographs were reviewed preoperatively, immediately postoperative, and at final follow up. The sagittal parameters measured included change in C2-C7 lordosis, T1 angle, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, proximal and distal adjacent segment lordosis. Patient-reported outcomes were obtained in the form of Neck Disability Index (NDI) scores and Visual Analog Scales (VAS) scores for the neck and arm. Radiographic diagnosis of ASD was determined by the presence of new or enlarged osteophytes, endplate sclerosis, disc space narrowing >50%, and/or increased calcification of the anterior longitudinal ligament (ALL) as presented by previous published studies. METHODS: Radiographic diagnosis of ASD was determined by the presence of new or enlarged osteophytes, endplate sclerosis, disc space narrowing >50%, and/or increased calcification of the anterior longitudinal ligament (ALL) as presented by previous published studies. Baseline patient characteristics were compared using chi-squared analysis and independent sample t-tests for categorical and continuous data, respectively. Bivariate and multivariate regressions were subsequently used to compare clinical outcomes between procedure groups. Multivariate analyses controlled for differences in baseline patient characteristics. RESULTS: A total of 101 ASD(+) patients were identified having undergone ACDF from 2008 to 2015 and compared to 131 ASD(−). The ASD (−) were free of ASD for at least 1 year. The groups were similar with regard to demographic and surgical variables, but with a predominance of males in the ASD group 61.2% (p=.001). Rigid plates were used in 42% of all constructs and were more represented in the ASD(−) than ASD(+) group (48% vs. 33%, respectively, p=.017). The most common levels included in the fusion were C5-7 (28%). For all patients, preoperative lordosis was increased from 4.8§11.4° to 7.9§10.2° postoperatively and improved to 9.4§9.9° at final follow-up. Patients with greater kyphosis throughout the cervical spine at final follow-up had increased odds of developing ASD (OR 0.97 per degree, p=.040). Patients with greater preoperative kyphosis through the planned fusion segment had increased odds of ASD (OR 0.93 per degree, p=.003). Patients who lost lordosis through the fusion from initial postop to final follow-up had greater odds of developing ASD (OR 0.85 per degree, p<0.001). Patients who had greater change in preoperative to postoperative fusion segment lordosis were found to exhibit a greater risk of ASD (OR 1.06 per degree, p=0.019). The SVA and T1 slope angles did not change substantially from preoperative to postoperative and there were no differences between ASD groups. The mean postoperative and final proximal and distal segment lordosis was
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also not different between groups except for significantly less proximal adjacent segment lordosis in ASD patients at final follow-up (0.2§5.0 vs. 1.4§4.4; p=.026). There were no significant differences between preoperative, postoperative, or change in patient-reported outcome surveys in patients with or without signs of radiographic ASD. CONCLUSIONS: Patients with a greater preoperative cervical kyphosis and kyphosis through the proposed fusion segment may have greater odds of develeoping radiographic adjacent segment degeneration. Similarly, those that had a greater greater correction of cervical lordosis postoperatively, and those who loss lordosis at the fusion segment also presented with increased odds of developing adjacent segment degeneration. Our results suggest that preoperative and postoperative measures of cervical spine alignment, specifically related to C2-C7 and fusion segment lordosis, may predict the development of radiographic signs of adjacent level pathology following an ACDF. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2018.06.428
Friday, September 28, 2018 10:30 AM–12:00 PM Deformity: Technical Factors 164. Incidence, risk factors and the natural history of proximal junctional kyphosis: review of long-term surgical outcomes using hybrid fusion constructs for adolescent idiopathic scoliosis Andrew J. Pugely, MD1, Luca Labianca, MD, PhD2, Piyush Kalakoti, MD1, Pawin Gajaseni, MD2, Stuart L. Weinstein, MD2; 1 University of Iowa, Iowa City, IA, USA; 2 Iowa City, IA, USA BACKGROUND CONTEXT: Proximal junctional kyphosis (PJK) is an unsolved radiographic phenomenon after corrective spinal deformity surgery with a high, but variable reported incidence. While known to influence outcomes in adults, the long-term clinical significance and natural history in children has not been well defined. Identifying incidence, riskfactors and natural course of PJK based on several proposed definitions in the literature using a large cohort may aid in enhancing our understanding of the disease entity. PURPOSE: In a single-surgeon series of AIS patients undergoing deformity correction using hybrid hooks or screw constructs, the study attempted to identify potential risk factors associated with the long-term development of PJK. Additionally, the study also defines PJK incidence and highlights the natural course of PJK development in children based on commonly proposed definitions in the literature. STUDY DESIGN/SETTING: Retrospective, single-surgeon series with a minimum 2-year follow-up. PATIENT SAMPLE: Overall, 253 eligible AIS patients with complete information on the proximal junctional angle (PJA) who underwent spinal deformity fusion (PSF) surgery by a single surgeon (SLW) at the University of Iowa between 2006 and 2015 that met the minimal criteria of 2-year follow-up were included. OUTCOME MEASURES: The primary outcome was to assess incidence of PJK development form preoperative to postoperative measurements based on two commonly utilized definitions: Glattes et al that defines PJK as PJA> 10°, and Bridwell et al classification that defines the disease entity based on the critical PJA above 20°. Secondary outcome was to investigate factors associated with PJK development based on patient demographics, radiological indices and outcomes, and describe the natural course of PJK development in AIS patients undergoing deformity correction. METHODS: AIS patients aged between 9 and 18 years undergoing primary long-construct PSF (UIV T2-4) between 2006 and 2015 with a minimum 2 years’ follow-up were included. Proximal junctional kyphosis was defined as a change in the PJA, according to Glattes et al and Bridwell et al classification from preop to postop. The incidence of PJK was defined at
Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.