Browsing by Author "Kanter, Adam S"
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Item Open Access A Multicenter Evaluation of Clinical and Radiographic Outcomes Following High-grade Spondylolisthesis Reduction and Fusion.(Clinical spine surgery, 2017-05) Gandhoke, Gurpreet S; Kasliwal, Manish K; Smith, Justin S; Nieto, JoAnne; Ibrahimi, David; Park, Paul; Lamarca, Frank; Shaffrey, Christopher; Okonkwo, David O; Kanter, Adam SObjective
A retrospective review of the clinical and radiographic outcomes from a multicenter study of surgical treatment for high-grade spondylolisthesis (HGS) in adults. The objective was to assess the safety of surgical reduction, its ability to correct regional deformity, and its clinical effectiveness.Methods
Retrospective, multicenter review of adults (age above 18 y) with lumbosacral HGS (Meyerding grade 3-5) treated surgically with open decompression, attempted reduction, posterior instrumentation, and interbody fusion. Preoperative and postoperative assessment of the Meyerding grade, slip angle, and sacral inclination were performed based on standing radiographs. Preoperative visual analog scale scores were compared with those at the mean follow-up period. Prolo and Oswestry Disability Index scores at most recent follow-up were assessed.Results
A total of 25 patients, aged 19-72 years, met inclusion criteria. Seventeen interbody cages were placed, including 15 transforaminal lumbar interbody fusions, 1 posterior lumbar interbody fusion, and 1 anterior lumbar interbody fusion. Five patients required sacral dome osteotomies. The average follow-up was 21.3 months.At most recent follow-up there was a statistically significant improvement in both the Meyerding grade and the slip angle (P<0.05). There was 1 intraoperative complication resulting in a neurological deficit (4%) and 1 intraoperative vertebral body fracture (4%). No additional surgery was required for any of these patients. There were no cases of nonunion or device failure except for 1 patient who suffered an unrelated traumatic injury 1 year after surgery. The mean Oswestry Disability Index and Prolo scores at mean follow-up of 21.3 months were 20% (minimum disability) and 8.2 (grade 1), respectively.Conclusions
The present study suggests that reduction, when accomplished in conjunction with wide neural element decompression and instrumented arthrodesis, is safe, effective, and durable with low rates of neurological injury, favorable clinical results, and high-fusion rates.Item Open Access A Multicenter Review of Superior Laryngeal Nerve Injury Following Anterior Cervical Spine Surgery.(Global spine journal, 2017-04) Tempel, Zachary J; Smith, Justin S; Shaffrey, Christopher; Arnold, Paul M; Fehlings, Michael G; Mroz, Thomas E; Riew, K Daniel; Kanter, Adam SA retrospective multicenter case-series study; case report and review of the literature.The anatomy and function of the superior laryngeal nerve (SLN) are well described; however, the consequences of SLN injury remain variable and poorly defined. The prevalence of SLN injury as a consequence of cervical spine surgery is difficult to discern as its clinical manifestations are often inconstant and frequently of a subclinical degree. A multicenter study was performed to better delineate the risk factors, prevalence, and outcomes of SLN injury.A retrospective multicenter case-series study involving 21 high-volume surgical centers from the AO Spine North America Clinical Research Network. Medical records for 17 625 patients who received subaxial cervical spine surgery from 2005 to 2011 were reviewed to identify occurrence of 21 predefined treatment complications. Descriptive statistics were provided for baseline patient characteristics. A retrospective review of the neurosurgical literature on SLN injury was also performed.A total of 8887 patients who underwent anterior cervical spine surgery at the participating institutions were screened, and 1 case of SLN palsy was identified. The prevalence ranged from 0% to 1.25% across all centers. The patient identified underwent a C4 corpectomy. The SLN injury was identified after the patient demonstrated difficulty swallowing postoperatively. He underwent placement of a percutaneous gastrostomy tube and his SLN palsy resolved by 6 weeks.This multicenter study demonstrates that identification of SLN injury occurs very infrequently. Symptomatic SLN injury is an exceedingly rare complication of anterior cervical spine surgery. The SLN is particularly vulnerable when exposing the more rostral levels of the cervical spine. Careful dissection and retraction of the longus coli may decrease the risk of SLN injury during anterior cervical surgery.Item Open Access A Multicenter Study of the Presentation, Treatment, and Outcomes of Cervical Dural Tears.(Global spine journal, 2017-04) O'Neill, Kevin R; Fehlings, Michael G; Mroz, Thomas E; Smith, Zachary A; Hsu, Wellington K; Kanter, Adam S; Steinmetz, Michael P; Arnold, Paul M; Mummaneni, Praveen V; Chou, Dean; Nassr, Ahmad; Qureshi, Sheeraz A; Cho, Samuel K; Baird, Evan O; Smith, Justin S; Shaffrey, Christopher; Tannoury, Chadi A; Tannoury, Tony; Gokaslan, Ziya L; Gum, Jeffrey L; Hart, Robert A; Isaacs, Robert E; Sasso, Rick C; Bumpass, David B; Bydon, Mohamad; Corriveau, Mark; De Giacomo, Anthony F; Derakhshan, Adeeb; Jobse, Bruce C; Lubelski, Daniel; Lee, Sungho; Massicotte, Eric M; Pace, Jonathan R; Smith, Gabriel A; Than, Khoi D; Riew, K DanielStudy design
Retrospective multicenter case series study.Objective
Because cervical dural tears are rare, most surgeons have limited experience with this complication. A multicenter study was performed to better understand the presentation, treatment, and outcomes following cervical dural tears.Methods
Multiple surgeons from 23 institutions retrospectively identified 21 rare complications that occurred between 2005 and 2011, including unintentional cervical dural tears. Demographic data and surgical history were obtained. Clinical outcomes following surgery were assessed, and any reoperations were recorded. Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA), Nurick classification (NuC), and Short-Form 36 (SF36) scores were recorded at baseline and final follow-up at certain centers. All data were collected, collated, and analyzed by a private research organization.Results
There were 109 cases of cervical dural tears among 18 463 surgeries performed. In 101 cases (93%) there was no clinical sequelae following successful dural tear repair. There were statistical improvements (P < .05) in mJOA and NuC scores, but not NDI or SF36 scores. No specific baseline or operative factors were found to be associated with the occurrence of dural tears. In most cases, no further postoperative treatments of the dural tear were required, while there were 13 patients (12%) that required subsequent treatment of cerebrospinal fluid drainage. Analysis of those requiring further treatments did not identify an optimum treatment strategy for cervical dural tears.Conclusions
In this multicenter study, we report our findings on the largest reported series (n = 109) of cervical dural tears. In a vast majority of cases, no subsequent interventions were required and no clinical sequelae were observed.Item Open Access A New Piece of the Puzzle to Understand Cervical Sagittal Alignment: Utilizing a Novel Angle δ to Describe the Relationship among T1 Vertebral Body Slope, Cervical Lordosis, and Cervical Sagittal Alignment.(Neurosurgery, 2020-03) Goldschmidt, Ezequiel; Angriman, Federico; Agarwal, Nitin; Trevisan, Marcos; Zhou, James; Chen, Katherine; Gerszten, Peter C; Kanter, Adam S; Okonkwo, David O; Passias, Peter; Scheer, Justin; Protopsaltis, Themistocles; Lafage, Virginie; Lafage, Renaud; Schwab, Frank; Bess, Shay; Ames, Christopher; Smith, Justin S; Shaffrey, Christopher I; Miller, Emily; Jain, Amit; Neuman, Brian; Sciubba, Daniel M; Burton, Douglas; Hamilton, D Kojo; International Spine Study Group (ISSG)Cervical alignment has become increasingly important in the planning of spine surgery. A relationship between the slope of T1 (T1S), the cervical lordosis (CL), and the overall cervical sagittal vertical axis (cSVA) has previously been demonstrated, but the exact nature of this relationship is poorly understood. In this study, we derive theoretical and empirical equations to better understand how T1S and CL affect cSVA. The first equation was developed on a theoretical basis using inherent trigonometric relationships of the cervical spine. By treating the cervical spine as the arc of a circumference, and by taking into account the cervical height (CH), the geometric relationship between theT1S, CL, and cSVA was described via a trigonometric identity utilizing a novel angle δ subtended by the CH and cSVA (δ = T1S-CL/2). The second equation was developed on an empiric basis by performing a multiple linear regression on data obtained from a retrospective review of a large multicenter deformity database. The theoretical equation determined that the value of cSVA could be expressed as: $cSVA\ = \ CH*{\rm{tan}}( {\pi /180*( {T1S - CL/2} )} )$. The empirical equation determined that value of cSVA could be expressed as: $cSVA=({1.1*T1} )\ - ( {0.43*CL} ) + 6.69$. In both, the sagittal alignment of the head over the shoulders is directly proportional to the T1S and inversely proportional to CL/2. These 2 equations may allow surgeons to better understand how the CL compensates for the T1S, to accurately predict the postoperative cSVA, and to customize cervical interbody grafts by taking into consideration each individual patient's specific cervical spine parameters.Item Open Access A Novel Tool for Deformity Surgery Planning: Determining the Magnitude of Lordotic Correction Required to Achieve a Desired Sagittal Vertical Axis.(World neurosurgery, 2017-08) Goldschmidt, Ezequiel; Angriman, Federico; Agarwal, Nitin; Zhou, James; Chen, Katherine; Tempel, Zachary J; Gerszten, Peter C; Kanter, Adam S; Okonkwo, David O; Passias, Peter; Scheer, Justin; Protopsaltis, Themistocles; Lafage, Virginie; Lafage, Renaud; Schwab, Frank; Bess, Shay; Ames, Christopher; Smith, Justin S; Shaffrey, Christopher I; Miller, Emily; Jain, Amit; Neuman, Brian; Sciubba, Daniel M; Burton, Douglas; Hamilton, D Kojo; International Spine Study GroupObjective
We sought to create a model capable of predicting the magnitude of pelvic incidence-lumbar lordosis (PI-LL) correction necessary to achieve a desired change in sagittal vertical axis (SVA).Methods
A retrospective review was conducted of a prospectively maintained multicenter adult spinal deformity database collected by the International Spine Study Group between 2009 and 2014. The independent variable of interest was the degree of correction achieved in the PI-LL mismatch 6 weeks after surgery. Primary outcome was the change in global sagittal alignment 6 weeks and 1 year after surgery. We used a linear mixed-effects model to determine the extent to which corrections in the PI-LL relationship affected postoperative changes in SVA.Results
A total of 1053 adult patients were identified. Of these patients, 590 were managed surgically. Eighty-seven surgically managed patients were excluded because of incomplete or missing PI-LL measurements on follow-up; the remaining 503 patients were selected for inclusion. For each degree of improvement in the PI-LL mismatch at 6 weeks, the SVA decreased by 2.18 mm (95% confidence interval, -2.56, -1.79; P < 0.01) and 1.67 mm (95% confidence interval, -2.07, -1.27; P < 0.01) at 6 weeks and 12 months, respectively. A high SVA measurement (>50 mm) 1 year after surgery was negatively associated with health-related quality of life as measured by the Scoliosis Research Society 22 outcomes assessment.Conclusions
We describe a novel model that shows how surgical correction of the PI-LL relationship affects postoperative changes in SVA. This model may enable surgeons to determine preoperatively the amount of LL necessary to achieve a desired change in SVA.Item Open Access Are Minimally Invasive Spine Surgeons or Classical Open Spine Surgeons More Consistent with Their Treatment of Adult Spinal Deformity?(World neurosurgery, 2022-09) Uribe, Juan S; Koffie, Robert M; Wang, Michael Y; Mundis, Gregory M; Kanter, Adam S; Eastlack, Robert K; Anand, Neel; Park, Paul; Smith, Justin S; Burton, Douglas C; Chou, Dean; Kelly, Michael P; Kim, Han Jo; Bess, Shay; Shaffrey, Christopher I; Schwab, Frank J; Lenke, Lawrence G; Mummaneni, Praveen VObjective
Spine surgeons have a heuristic sense of how to surgically restore alignment and address adult spinal deformity (ASD) symptoms, but consensus on the extent of treatment remains unclear. We sought to determine the variability of surgical approaches in treating ASD.Methods
Sixteen spine surgeons were surveyed on treatment approaches in 10 select ASD cases. We repeated the survey with the same surgeons 4 weeks later, with cases ordered differently. We examined the variability in length of construct, use of interbody spacers, osteotomies, and pelvic fixation frequency.Results
Treatment approaches for each case varied by surgeon, with some surgeons opting for long fusion constructs in cases for which others offered no surgery. There was no consensus among surgeons on the number of levels fused, interbody spacer use, or anterior/posterior osteotomies. Intersurgeon and intrasurgeon variability was 48% (kappa = 0.31) and 59% (kappa = 0.44) for surgeons performing minimally invasive surgery (MIS) versus 37% (kappa = 0.21) and 47% (kappa = 0.30) for those performing open surgery. In the second-round survey, 8 of 15 (53%) surgeons substantially changed the construct length, number of interbody spacers, and osteotomies in at least half the cases they previously reviewed. Surgeons performing MIS versus open surgery were less likely to extend constructs to the pelvis (42.5% vs. 67.5%; P = 0.02), but construct length was not correlated with whether a surgeon performed MIS or open surgery.Conclusions
Spinal deformity surgeons lack consensus on the optimal surgical approach for treating ASD. Classifying surgeons as performing MIS or open surgery does not mitigate this variability.Item Open Access Can a Minimal Clinically Important Difference Be Achieved in Elderly Patients with Adult Spinal Deformity Who Undergo Minimally Invasive Spinal Surgery?(World neurosurgery, 2016-02) Park, Paul; Okonkwo, David O; Nguyen, Stacie; Mundis, Gregory M; Than, Khoi D; Deviren, Vedat; La Marca, Frank; Fu, Kai-Ming; Wang, Michael Y; Uribe, Juan S; Anand, Neel; Fessler, Richard; Nunley, Pierce D; Chou, Dean; Kanter, Adam S; Shaffrey, Christopher I; Akbarnia, Behrooz A; Passias, Peter G; Eastlack, Robert K; Mummaneni, Praveen V; International Spine Study GroupBackground
Older age has been considered a relative contraindication to complex spinal procedures. Minimally invasive surgery (MIS) techniques to treat patients with adult spinal deformity (ASD) have emerged with the potential benefit of decreased approach-related morbidity.Objective
To determine whether a minimal clinically important difference (MCID) could be achieved in patients ages ≥ 65 years with ASD who underwent MIS.Methods
Multicenter database of patients who underwent MIS for ASD was queried. Outcome metrics assessed were Oswestry Disability Index (ODI) and visual analog scale (VAS) scores for back and leg pain. On the basis of published reports, MCID was defined as a positive change of 12.8 ODI, 1.2 VAS back pain, and 1.6 VAS leg pain.Results
Forty-two patients were identified. Mean age was 70.3 years; 31 (73.8%) were women. Preoperatively, mean coronal curve, pelvic tilt, pelvic incidence to lumbar lordosis mismatch, and sagittal vertical axis were 35°, 24.6°, 14.2°, and 4.7 cm, respectively. Postoperatively, mean coronal curve, pelvic tilt, pelvic incidence to lumbar lordosis, and sagittal vertical axis were 18°, 25.4°, 11.9°, and 4.9 cm, respectively. A mean of 5.0 levels was treated posteriorly, and a mean of 4.0 interbody fusions was performed. Mean ODI improved from 47.1 to 25.1. Mean VAS back and leg pain scores improved from 6.8 and 5.9 to 2.7 and 2.7, respectively. Mean follow-up was 32.1 months. For ODI, 64.3% of patients achieved MCID. For VAS back and leg pain, 82.9% and 72.2%, respectively, reached MCID.Conclusions
MCID represents the threshold at which patients feel a meaningful clinical improvement has occurred. Our study results suggest that the majority of elderly patients with modest ASD can achieve MCID with MIS.Item Open Access Clinical and radiographic parameters associated with best versus worst clinical outcomes in minimally invasive spinal deformity surgery.(Journal of neurosurgery. Spine, 2016-07) Than, Khoi D; Park, Paul; Fu, Kai-Ming; Nguyen, Stacie; Wang, Michael Y; Chou, Dean; Nunley, Pierce D; Anand, Neel; Fessler, Richard G; Shaffrey, Christopher I; Bess, Shay; Akbarnia, Behrooz A; Deviren, Vedat; Uribe, Juan S; La Marca, Frank; Kanter, Adam S; Okonkwo, David O; Mundis, Gregory M; Mummaneni, Praveen V; International Spine Study GroupOBJECTIVE Minimally invasive surgery (MIS) techniques are increasingly used to treat adult spinal deformity. However, standard minimally invasive spinal deformity techniques have a more limited ability to restore sagittal balance and match the pelvic incidence-lumbar lordosis (PI-LL) than traditional open surgery. This study sought to compare "best" versus "worst" outcomes of MIS to identify variables that may predispose patients to postoperative success. METHODS A retrospective review of minimally invasive spinal deformity surgery cases was performed to identify parameters in the 20% of patients who had the greatest improvement in Oswestry Disability Index (ODI) scores versus those in the 20% of patients who had the least improvement in ODI scores at 2 years' follow-up. RESULTS One hundred four patients met the inclusion criteria, and the top 20% of patients in terms of ODI improvement at 2 years (best group, 22 patients) were compared with the bottom 20% (worst group, 21 patients). There were no statistically significant differences in age, body mass index, pre- and postoperative Cobb angles, pelvic tilt, pelvic incidence, levels fused, operating room time, and blood loss between the best and worst groups. However, the mean preoperative ODI score was significantly higher (worse disability) at baseline in the group that had the greatest improvement in ODI score (58.2 vs 39.7, p < 0.001). There was no difference in preoperative PI-LL mismatch (12.8° best vs 19.5° worst, p = 0.298). The best group had significantly less postoperative sagittal vertical axis (SVA; 3.4 vs 6.9 cm, p = 0.043) and postoperative PI-LL mismatch (10.4° vs 19.4°, p = 0.027) than the worst group. The best group also had better postoperative visual analog scale back and leg pain scores (p = 0.001 and p = 0.046, respectively). CONCLUSIONS The authors recommend that spinal deformity surgeons using MIS techniques focus on correcting a patient's PI-LL mismatch to within 10° and restoring SVA to < 5 cm. Restoration of these parameters seems to impact which patients will attain the greatest degree of improvement in ODI outcomes, while the spines of patients who do the worst are not appropriately corrected and may be fused into a fixed sagittal plane deformity.Item Open Access Comparison of Complications and Clinical and Radiographic Outcomes Between Nonobese and Obese Patients with Adult Spinal Deformity Undergoing Minimally Invasive Surgery.(World neurosurgery, 2016-03) Park, Paul; Wang, Michael Y; Nguyen, Stacie; Mundis, Gregory M; La Marca, Frank; Uribe, Juan S; Anand, Neel; Okonkwo, David O; Kanter, Adam S; Fessler, Richard; Eastlack, Robert K; Chou, Dean; Deviren, Vedat; Nunley, Pierce D; Shaffrey, Christopher I; Mummaneni, Praveen V; International Spine Study GroupObjective
Obesity can be associated with increased complications and potentially worse outcomes. We aimed to evaluate the impact of obesity on complications and outcomes in patients with adult spinal deformity (ASD) who underwent minimally invasive surgery (MIS).Methods
A multicenter database of patients with ASD treated via MIS was queried. Of 190 patients in the database, 77 fit the inclusion criteria of 3 or more spinal levels treated minimally invasively. Patients were divided by body mass index (BMI) <30 (nonobese; n = 59) and BMI ≥ 30 (obese; n = 18).Results
Mean BMI was 24.6 nonobese and 35.0 obese (P < 0.001). There were mean 3.8 interbody fusions nonobese and 4.7 obese (P = 0.065). Levels treated posteriorly averaged 5.8 nonobese and 5.9 obese (P = 0.502). Mean follow-up was 34.4 months nonobese and 35.3 months obese (P = 0.976). Baseline radiographic parameters were similar between groups. Postoperatively, SVA averaged 83.9 mm obese and 20.4 mm nonobese (P = 0.002). Postoperative lumbar lordosis-pelvic incidence mismatch averaged 17.9° obese and 9.9° nonobese (P = 0.028). Both groups had improvement in Oswestry Disability Index (ODI) scores with no difference in postoperative ODI scores between groups (P = 0.090). Similarly, both groups had decreased VAS scores for back and leg pain with no difference between groups postoperatively. Twenty (33.9%) nonobese patients versus 7 (38.9%) obese patients had complications (P = 0.452).Conclusions
Our results suggest that obesity does not negatively impact complication rate or clinical outcomes in patients with ASD treated via MIS approaches.Item Open Access Comparison of radiographic results after minimally invasive, hybrid, and open surgery for adult spinal deformity: a multicenter study of 184 patients.(Neurosurgical focus, 2014-05) Haque, Raqeeb M; Mundis, Gregory M; Ahmed, Yousef; El Ahmadieh, Tarek Y; Wang, Michael Y; Mummaneni, Praveen V; Uribe, Juan S; Okonkwo, David O; Eastlack, Robert K; Anand, Neel; Kanter, Adam S; La Marca, Frank; Akbarnia, Behrooz A; Park, Paul; Park, Paul; Lafage, Virginie; Terran, Jamie S; Shaffrey, Christopher I; Klineberg, Eric; Deviren, Vedat; Fessler, Richard G; International Spine Study GroupObject
Various surgical approaches, including open, minimally invasive, and hybrid techniques, have gained momentum in the management of adult spinal deformity. However, few data exist on the radiographic outcomes of different surgical techniques. The objective of this study was to compare the radiographic and clinical outcomes of the surgical techniques used in the treatment of adult spinal deformity.Methods
The authors conducted a retrospective review of two adult spinal deformity patient databases, a prospective open surgery database and a retrospective minimally invasive surgery (MIS) and hybrid surgery database. The time frame of enrollment in this study was from 2007 to 2012. Spinal deformity patients were stratified into 3 surgery groups: MIS, hybrid surgery, and open surgery. The following pre- and postoperative radiographic parameters were assessed: lumbar major Cobb angle, lumbar lordosis, pelvic incidence minus lumbar lordosis (PI-LL), sagittal vertical axis, and pelvic tilt. Scores on the Oswestry Disability Index (ODI) and a visual analog scale (VAS) for both back and leg pain were also obtained from each patient.Results
Of the 234 patients with adult spinal deformity, 184 patients had pre- and postoperative radiographs and were thus included in the study (MIS, n = 42; hybrid, n = 33; open, n = 109). Patients were a mean of 61.7 years old and had a mean body mass index of 26.9 kg/m(2). Regarding radiographic outcomes, the MIS group maintained a significantly smaller mean lumbar Cobb angle (13.1°) after surgery compared with the open group (20.4°, p = 0.002), while the hybrid group had a significantly larger lumbar curve correction (26.6°) compared with the MIS group (18.8°, p = 0.045). The mean change in the PI-LL was larger for the hybrid group (20.6°) compared with the open (10.2°, p = 0.023) and MIS groups (5.5°, p = 0.003). The mean sagittal vertical axis correction was greater for the open group (25 mm) compared with the MIS group (≤ 1 mm, p = 0.008). Patients in the open group had a significantly larger postoperative thoracic kyphosis (41.45°) compared with the MIS patients (33.5°, p = 0.005). There were no significant differences between groups in terms of pre- and postoperative mean ODI and VAS scores at the 1-year follow-up. However, patients in the MIS group had much lower estimated blood loss and transfusion rates compared with patients in the hybrid or open groups (p < 0.001). Operating room time was significantly longer with the hybrid group compared with the MIS and open groups (p < 0.001). Major complications occurred in 14% of patients in the MIS group, 14% in the hybrid group, and 45% in the open group (p = 0.032).Conclusions
This study provides valuable baseline characteristics of radiographic parameters among 3 different surgical techniques used in the treatment of adult spinal deformity. Each technique has advantages, but much like any surgical technique, the positive and negative elements must be considered when tailoring a treatment to a patient. Minimally invasive surgical techniques can result in clinical outcomes at 1 year comparable to those obtained from hybrid and open surgical techniques.Item Open Access Comparison of two minimally invasive surgery strategies to treat adult spinal deformity.(Journal of neurosurgery. Spine, 2015-04) Park, Paul; Wang, Michael Y; Lafage, Virginie; Nguyen, Stacie; Ziewacz, John; Okonkwo, David O; Uribe, Juan S; Eastlack, Robert K; Anand, Neel; Haque, Raqeeb; Fessler, Richard G; Kanter, Adam S; Deviren, Vedat; La Marca, Frank; Smith, Justin S; Shaffrey, Christopher I; Mundis, Gregory M; Mummaneni, Praveen V; International Spine Study GroupObject
Minimally invasive surgery (MIS) techniques are becoming a more common means of treating adult spinal deformity (ASD). The aim of this study was to compare the hybrid (HYB) surgical approach, involving minimally invasive lateral interbody fusion with open posterior instrumented fusion, to the circumferential MIS (cMIS) approach to treat ASD.Methods
The authors performed a retrospective, multicenter study utilizing data collected in 105 patients with ASD who were treated via MIS techniques. Criteria for inclusion were age older than 45 years, coronal Cobb angle greater than 20°, and a minimum of 1 year of follow-up. Patients were stratified into 2 groups: HYB (n = 62) and cMIS (n = 43).Results
The mean age was 60.7 years in the HYB group and 61.0 years in the cMIS group (p = 0.910). A mean of 3.6 interbody fusions were performed in the HYB group compared with a mean of 4.0 interbody fusions in the cMIS group (p = 0.086). Posterior fusion involved a mean of 6.9 levels in the HYB group and a mean of 5.1 levels in the cMIS group (p = 0.003). The mean follow-up was 31.3 months for the HYB group and 38.3 months for the cMIS group. The mean Oswestry Disability Index (ODI) score improved by 30.6 and 25.7, and the mean visual analog scale (VAS) scores for back/leg pain improved by 2.4/2.5 and 3.8/4.2 for the HYB and cMIS groups, respectively. There was no significant difference between groups with regard to ODI or VAS scores. For the HYB group, the lumbar coronal Cobb angle decreased by 13.5°, lumbar lordosis (LL) increased by 8.2°, sagittal vertical axis (SVA) decreased by 2.2 mm, and LL-pelvic incidence (LL-PI) mismatch decreased by 8.6°. For the cMIS group, the lumbar coronal Cobb angle decreased by 10.3°, LL improved by 3.0°, SVA increased by 2.1 mm, and LL-PI decreased by 2.2°. There were no significant differences in these radiographic parameters between groups. The complication rate, however, was higher in the HYB group (55%) than in the cMIS group (33%) (p = 0.024).Conclusions
Both HYB and cMIS approaches resulted in clinical improvement, as evidenced by decreased ODI and VAS pain scores. While there was no significant difference in degree of radiographic correction between groups, the HYB group had greater absolute improvement in degree of lumbar coronal Cobb angle correction, increased LL, decreased SVA, and decreased LL-PI. The complication rate, however, was higher with the HYB approach than with the cMIS approach.Item Open Access Complications in adult spinal deformity surgery: an analysis of minimally invasive, hybrid, and open surgical techniques.(Neurosurgical focus, 2014-05) Uribe, Juan S; Deukmedjian, Armen R; Mummaneni, Praveen V; Fu, Kai-Ming G; Mundis, Gregory M; Okonkwo, David O; Kanter, Adam S; Eastlack, Robert; Wang, Michael Y; Anand, Neel; Fessler, Richard G; La Marca, Frank; Park, Paul; Lafage, Virginie; Deviren, Vedat; Bess, Shay; Shaffrey, Christopher I; International Spine Study GroupObject
It is hypothesized that minimally invasive surgical techniques lead to fewer complications than open surgery for adult spinal deformity (ASD). The goal of this study was to analyze matched patient cohorts in an attempt to isolate the impact of approach on adverse events.Methods
Two multicenter databases queried for patients with ASD treated via surgery and at least 1 year of follow-up revealed 280 patients who had undergone minimally invasive surgery (MIS) or a hybrid procedure (HYB; n = 85) or open surgery (OPEN; n = 195). These patients were divided into 3 separate groups based on the approach performed and were propensity matched for age, preoperative sagittal vertebral axis (SVA), number of levels fused posteriorly, and lumbar coronal Cobb angle (CCA) in an attempt to neutralize these patient variables and to make conclusions based on approach only. Inclusion criteria for both databases were similar, and inclusion criteria specific to this study consisted of an age > 45 years, CCA > 20°, 3 or more levels of fusion, and minimum of 1 year of follow-up. Patients in the OPEN group with a thoracic CCA > 75° were excluded to further ensure a more homogeneous patient population.Results
In all, 60 matched patients were available for analysis (MIS = 20, HYB = 20, OPEN = 20). Blood loss was less in the MIS group than in the HYB and OPEN groups, but a significant difference was only found between the MIS and the OPEN group (669 vs 2322 ml, p = 0.001). The MIS and HYB groups had more fused interbody levels (4.5 and 4.1, respectively) than the OPEN group (1.6, p < 0.001). The OPEN group had less operative time than either the MIS or HYB group, but it was only statistically different from the HYB group (367 vs 665 minutes, p < 0.001). There was no significant difference in the duration of hospital stay among the groups. In patients with complete data, the overall complication rate was 45.5% (25 of 55). There was no significant difference in the total complication rate among the MIS, HYB, and OPEN groups (30%, 47%, and 63%, respectively; p = 0.147). No intraoperative complications were reported for the MIS group, 5.3% for the HYB group, and 25% for the OPEN group (p < 0.03). At least one postoperative complication occurred in 30%, 47%, and 50% (p = 0.40) of the MIS, HYB, and OPEN groups, respectively. One major complication occurred in 30%, 47%, and 63% (p = 0.147) of the MIS, HYB, and OPEN groups, respectively. All patients had significant improvement in both the Oswestry Disability Index (ODI) and visual analog scale scores after surgery (p < 0.001), although the MIS group did not have significant improvement in leg pain. The occurrence of complications had no impact on the ODI.Conclusions
Results in this study suggest that the surgical approach may impact complications. The MIS group had significantly fewer intraoperative complications than did either the HYB or OPEN groups. If the goals of ASD surgery can be achieved, consideration should be given to less invasive techniques.Item Open Access Does Minimally Invasive Percutaneous Posterior Instrumentation Reduce Risk of Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery? A Propensity-Matched Cohort Analysis.(Neurosurgery, 2016-01) Mummaneni, Praveen V; Park, Paul; Fu, Kai-Ming; Wang, Michael Y; Nguyen, Stacie; Lafage, Virginie; Uribe, Juan S; Ziewacz, John; Terran, Jamie; Okonkwo, David O; Anand, Neel; Fessler, Richard; Kanter, Adam S; LaMarca, Frank; Deviren, Vedat; Bess, R Shay; Schwab, Frank J; Smith, Justin S; Akbarnia, Behrooz A; Mundis, Gregory M; Shaffrey, Christopher I; International Spine Study GroupBackground
Proximal junctional kyphosis (PJK) is a known complication after spinal deformity surgery. One potential cause is disruption of posterior muscular tension band during pedicle screw placement.Objective
To investigate the effect of minimally invasive surgery (MIS) on PJK.Methods
A multicenter database of patients who underwent deformity surgery was propensity matched for pelvic incidence (PI) to lumbar lordosis (LL) mismatch and change in LL. Radiographic PJK was defined as proximal junctional angle >10°. Sixty-eight patients made up the circumferential MIS (cMIS) group, and 68 were in the hybrid (HYB) surgery group (open screw placement).Results
Preoperatively, there was no difference in age, body mass index, PI-LL mismatch, or sagittal vertical axis. The mean number of levels treated posteriorly was 4.7 for cMIS and 8.2 for HYB (P < .001). Both had improved LL and PI-LL mismatch postoperatively. Sagittal vertical axis remained physiological for the cMIS and HYB groups. Oswestry Disability Index scores were significantly improved in both groups. Radiographic PJK developed in 31.3% of the cMIS and 52.9% of the HYB group (P = .01). Reoperation for PJK was 4.5% for the cMIS and 10.3% for the HYB group (P = .20). Subgroup analysis for patients undergoing similar levels of posterior instrumentation in the cMIS and HYB groups found a PJK rate of 48.1% and 53.8% (P = .68) and a reoperation rate of 11.1% and 19.2%, respectively (P = .41). Mean follow-up was 32.8 months.Conclusion
Overall rates of radiographic PJK and reoperation for PJK were not significantly decreased with MIS pedicle screw placement. However, a larger comparative study is needed to confirm that MIS pedicle screw placement does not affect PJK.Item Open Access Factors affecting approach selection for minimally invasive versus open surgery in the treatment of adult spinal deformity: analysis of a prospective, nonrandomized multicenter study.(Journal of neurosurgery. Spine, 2020-06) Park, Paul; Than, Khoi D; Mummaneni, Praveen V; Nunley, Pierce D; Eastlack, Robert K; Uribe, Juan S; Wang, Michael Y; Le, Vivian; Fessler, Richard G; Okonkwo, David O; Kanter, Adam S; Anand, Neel; Chou, Dean; Fu, Kai-Ming G; Haddad, Alexander F; Shaffrey, Christopher I; Mundis, Gregory M; International Spine Study GroupObjective
Surgical decision-making and planning is a key factor in optimizing outcomes in adult spinal deformity (ASD). Minimally invasive spinal (MIS) strategies for ASD have been increasingly used as an option to decrease postoperative morbidity. This study analyzes factors involved in the selection of either a traditional open approach or a minimally invasive approach to treat ASD in a prospective, nonrandomized multicenter trial. All centers had at least 5 years of experience in minimally invasive techniques for ASD.Methods
The study enrolled 268 patients, of whom 120 underwent open surgery and 148 underwent MIS surgery. Inclusion criteria included age ≥ 18 years, and at least one of the following criteria: coronal curve (CC) ≥ 20°, sagittal vertical axis (SVA) > 5 cm, pelvic tilt (PT) > 25°, or thoracic kyphosis (TK) > 60°. Surgical approach selection was made at the discretion of the operating surgeon. Preoperative significant differences were included in a multivariate logistic regression analysis to determine odds ratios (ORs) for approach selection.Results
Significant preoperative differences (p < 0.05) between open and MIS groups were noted for age (61.9 vs 66.7 years), numerical rating scale (NRS) back pain score (7.8 vs 7), CC (36° vs 26.1°), PT (26.4° vs 23°), T1 pelvic angle (TPA; 25.8° vs 21.7°), and pelvic incidence-lumbar lordosis (PI-LL; 19.6° vs 14.9°). No significant differences in BMI (29 vs 28.5 kg/m2), NRS leg pain score (5.2 vs 5.7), Oswestry Disability Index (48.4 vs 47.2), Scoliosis Research Society 22-item questionnaire score (2.7 vs 2.8), PI (58.3° vs 57.1°), LL (38.9° vs 42.3°), or SVA (73.8 mm vs 60.3 mm) were found. Multivariate analysis found that age (OR 1.05, p = 0.002), VAS back pain score (OR 1.21, p = 0.016), CC (OR 1.03, p < 0.001), decompression (OR 4.35, p < 0.001), and TPA (OR 1.09, p = 0.023) were significant factors in approach selection.Conclusions
Increasing age was the primary driver for selecting MIS surgery. Conversely, increasingly severe deformities and the need for open decompression were the main factors influencing the selection of traditional open surgery. As experience with MIS surgery continues to accumulate, future longitudinal evaluation will reveal if more experience, use of specialized treatment algorithms, refinement of techniques, and technology will expand surgeon adoption of MIS techniques for adult spinal deformity.Item Open Access Impact of case type, length of stay, institution type, and comorbidities on Medicare diagnosis-related group reimbursement for adult spinal deformity surgery.(Neurosurgical focus, 2017-12) Nunley, Pierce D; Mundis, Gregory M; Fessler, Richard G; Park, Paul; Zavatsky, Joseph M; Uribe, Juan S; Eastlack, Robert K; Chou, Dean; Wang, Michael Y; Anand, Neel; Frank, Kelly A; Stone, Marcus B; Kanter, Adam S; Shaffrey, Christopher I; Mummaneni, Praveen V; International Spine Study GroupOBJECTIVE The aim of this study was to educate medical professionals about potential financial impacts of improper diagnosis-related group (DRG) coding in adult spinal deformity (ASD) surgery. METHODS Medicare's Inpatient Prospective Payment System PC Pricer database was used to collect 2015 reimbursement data for ASD procedures from 12 hospitals. Case type, hospital type/location, number of operative levels, proper coding, length of stay, and complications/comorbidities (CCs) were analyzed for effects on reimbursement. DRGs were used to categorize cases into 3 types: 1) anterior or posterior only fusion, 2) anterior fusion with posterior percutaneous fixation with no dorsal fusion, and 3) combined anterior and posterior fixation and fusion. RESULTS Pooling institutions, cases were reimbursed the same for single-level and multilevel ASD surgery. Longer stay, from 3 to 8 days, resulted in an additional $1400 per stay. Posterior fusion was an additional $6588, while CCs increased reimbursement by approximately $13,000. Academic institutions received higher reimbursement than private institutions, i.e., approximately $14,000 (Case Types 1 and 2) and approximately $16,000 (Case Type 3). Urban institutions received higher reimbursement than suburban institutions, i.e., approximately $3000 (Case Types 1 and 2) and approximately $3500 (Case Type 3). Longer stay, from 3 to 8 days, increased reimbursement between $208 and $494 for private institutions and between $1397 and $1879 for academic institutions per stay. CONCLUSIONS Reimbursement is based on many factors not controlled by surgeons or hospitals, but proper DRG coding can significantly impact the financial health of hospitals and availability of quality patient care.Item Unknown Incremental benefits of circumferential minimally invasive surgery for increasingly frail patients with adult spinal deformity.(Journal of neurosurgery. Spine, 2023-04) Passias, Peter G; Tretiakov, Peter S; Nunley, Pierce D; Wang, Michael Y; Park, Paul; Kanter, Adam S; Okonkwo, David O; Eastlack, Robert K; Mundis, Gregory M; Chou, Dean; Agarwal, Nitin; Fessler, Richard G; Uribe, Juan S; Anand, Neel; Than, Khoi D; Brusko, Gregory; Fu, Kai-Ming; Turner, Jay D; Le, Vivian P; Line, Breton G; Ames, Christopher P; Smith, Justin S; Shaffrey, Christopher I; Hart, Robert A; Burton, Douglas; Lafage, Renaud; Lafage, Virginie; Schwab, Frank; Bess, Shay; Mummaneni, Praveen VObjective
Circumferential minimally invasive surgery (cMIS) may provide incremental benefits compared with open surgery for patients with increasing frailty status by decreasing peri- and postoperative complications.Methods
Operative patients with adult spinal deformity (ASD) ≥ 18 years old with baseline and 2-year postoperative data were assessed. With propensity score matching, patients who underwent cMIS (cMIS group) were matched with similar patients who underwent open surgery (open group) based on baseline BMI, C7-S1 sagittal vertical axis, pelvic incidence to lumbar lordosis mismatch, and S1 pelvic tilt. The Passias modified ASD frailty index (mASD-FI) was used to determine patient frailty stratification as not frail, frail, or severely frail. Baseline and postoperative factors were assessed using two-way analysis of covariance (ANCOVA) and multivariate ANCOVA while controlling for baseline age, Charlson Comorbidity Index (CCI) score, and number of levels fused.Results
After propensity score matching, 170 ASD patients (mean age 62.71 ± 13.64 years, 75.0% female, mean BMI 29.25 ± 6.60 kg/m2) were included, split evenly between the cMIS and open groups. Surgically, patients in the open group had higher numbers of posterior levels fused (p = 0.021) and were more likely to undergo three-column osteotomies (p > 0.05). Perioperatively, cMIS patients had lower intraoperative blood loss and decreased use of cell saver across frailty groups (with adjustment for baseline age, CCI score, and levels fused), as well as fewer perioperative complications (p < 0.001). Adjusted analysis also revealed that compared to open patients, increasingly frail patients in the cMIS group were also more likely to demonstrate greater improvement in 1- and 2-year postoperative scores for the Oswestry Disability Index, SRS-36 (total), EQ-5D and SF-36 (all p < 0.05). With regard to postoperative complications, increasingly frail patients in the cMIS group were also noted to experience significantly fewer complications overall (p = 0.036) and fewer major intraoperative complications (p = 0.039). The cMIS patients were also less likely to need a reoperation than their open group counterparts (p = 0.043).Conclusions
Surgery performed with a cMIS technique may offer acceptable outcomes, with diminishment of perioperative complications and mitigation of catastrophic outcomes, in increasingly frail patients who may not be candidates for surgery using traditional open techniques. However, further studies should be performed to investigate the long-term impact of less optimal alignment in this population.Item Unknown Introduction: Adult spinal deformity: pathophysiology and corrective measures.(Neurosurgical focus, 2014-05) Kanter, Adam S; Shaffrey, Christopher I; Mummaneni, Praveen; Wang, Michael Y; Uribe, Juan SItem Unknown Less invasive spinal deformity surgery: the impact of the learning curve at tertiary spine care centers.(Journal of neurosurgery. Spine, 2019-08) Wang, Michael Y; Tran, Stacie; Brusko, G Damian; Eastlack, Robert; Park, Paul; Nunley, Pierce D; Kanter, Adam S; Uribe, Juan S; Anand, Neel; Okonkwo, David O; Than, Khoi D; Shaffrey, Christopher I; Lafage, Virginie; Mundis, Gregory M; Mummaneni, Praveen V; MIS-ISSG GroupObjective
The past decade has seen major advances in techniques for treating more complex spinal disorders using minimally invasive surgery (MIS). While appealing from the standpoint of patient perioperative outcomes, a major impediment to adoption has been the significant learning curve in utilizing MIS techniques.Methods
Data were retrospectively analyzed from a multicenter series of adult spinal deformity surgeries treated at eight tertiary spine care centers in the period from 2008 to 2015. All patients had undergone a less invasive or hybrid approach for a deformity correction satisfying the following inclusion criteria at baseline: coronal Cobb angle ≥ 20°, sagittal vertical axis (SVA) > 5 cm, or pelvic tilt > 20°. Analyzed data included baseline demographic details, severity of deformity, surgical metrics, clinical outcomes (numeric rating scale [NRS] score and Oswestry Disability Index [ODI]), radiographic outcomes, and complications. A minimum follow-up of 2 years was required for study inclusion.Results
Across the 8-year study period, among 222 patients, there was a trend toward treating increasingly morbid patients, with the mean age increasing from 50.7 to 62.4 years (p = 0.013) and the BMI increasing from 25.5 to 31.4 kg/m2 (p = 0.12). There was no statistical difference in the severity of coronal and sagittal deformity treated over the study period. With regard to radiographic changes following surgery, there was an increasing emphasis on sagittal correction and, conversely, less coronal correction. There was no statistically significant difference in clinical outcomes over the 8-year period, and meaningful improvements were seen in all years (ODI range of improvement: 15.0-26.9). Neither were there statistically significant differences in major complications; however, minor complications were seen less often as the surgeons gained experience (p = 0.064). Operative time was decreased on average by 47% over the 8-year period.Trends in surgical practice were seen as well. Total fusion construct length was unchanged until the last year when there was a marked decrease in conjunction with a decrease in interbody levels treated (p = 0.004) while obtaining a higher degree of sagittal correction, suggesting more selective but powerful interbody reduction methods as reflected by an increase in the lateral and anterior column resection techniques being utilized.Conclusions
The use of minimally invasive methods for adult spinal deformity surgery has evolved over the past decade. Experienced surgeons are treating older and more morbid patients with similar outcomes. A reliance on selective, more powerful interbody approaches is increasing as well.Item Unknown Less invasive surgery for treating adult spinal deformities: ceiling effects for deformity correction with 3 different techniques.(Neurosurgical focus, 2014-05) Wang, Michael Y; Mummaneni, Praveen V; Fu, Kai-Ming G; Anand, Neel; Okonkwo, David O; Kanter, Adam S; La Marca, Frank; Fessler, Richard; Uribe, Juan; Shaffrey, Christopher I; Lafage, Virginie; Haque, Raqeeb M; Deviren, Vedat; Mundis, Gregory M; Minimally Invasive Surgery Section of the International Spine Study GroupObject
Minimally invasive surgery (MIS) options for the treatment of adult spinal deformity (ASD) have advanced significantly over the past decade. However, a wide array of options have been described as being MIS or less invasive. In this study the authors investigated a multiinstitutional cohort of patients with ASD who were treated with less invasive methods to determine the extent of deformity correction achieved.Methods
This study was a retrospective review of multicenter prospectively collected data in 85 consecutive patients with ASD undergoing MIS surgery. Inclusion criteria were as follows: age older than 45 years; minimum 20° coronal lumbar Cobb angle; and 1 year of follow-up. Procedures were classified as follows: 1) stand-alone (n = 7); 2) circumferential MIS (n = 43); or 3) hybrid (n = 35).Results
An average of 4.2 discs (range 3-7) were fused, with a mean follow-up duration of 26.1 months in this study. For the stand-alone group the preoperative Cobb range was 22°-51°, with 57% greater than 30° and 28.6% greater than 50°. The mean Cobb angle improved from 35.7° to 30°. A ceiling effect of 23° for curve correction was observed, regardless of preoperative curve severity. For the circumferential MIS group the preoperative Cobb range was 19°-62°, with 44% greater than 30° and 5% greater than 50°. The mean Cobb angle improved from 32° to 12°. A ceiling effect of 34° for curve correction was observed. For the hybrid group the preoperative Cobb range was 23°-82°, with 74% greater than 30° and 23% greater than 50°. The mean Cobb angle improved from 43° to 15°. A ceiling effect of 55° for curve correction was observed.Conclusions
Specific procedures for treating ASD have particular limitations for scoliotic curve correction. Less invasive techniques were associated with a reduced ability to straighten the spine, particularly with advanced curves. These data can guide preoperative technique selection when treating patients with ASD.Item Unknown Neuroanesthesia Guidelines for Optimizing Transcranial Motor Evoked Potential Neuromonitoring During Deformity and Complex Spinal Surgery: A Delphi Consensus Study.(Spine, 2020-07) Walker, Corey T; Kim, Han Jo; Park, Paul; Lenke, Lawrence G; Weller, Mark A; Smith, Justin S; Nemergut, Edward C; Sciubba, Daniel M; Wang, Michael Y; Shaffrey, Christopher; Deviren, Vedat; Mummaneni, Praveen V; Chang, Joyce M; Mummaneni, Valli P; Than, Khoi D; Berjano, Pedro; Eastlack, Robert K; Mundis, Gregory M; Kanter, Adam S; Okonkwo, David O; Shin, John H; Lewis, Jason M; Koski, Tyler; Hoh, Daniel J; Glassman, Steven D; Vinci, Susan B; Daniels, Alan H; Clavijo, Claudia F; Turner, Jay D; McLawhorn, Marc; Uribe, Juan SStudy design
Expert opinion-modified Delphi study.Objective
We used a modified Delphi approach to obtain consensus among leading spinal deformity surgeons and their neuroanesthesiology teams regarding optimal practices for obtaining reliable motor evoked potential (MEP) signals.Summary of background data
Intraoperative neurophysiological monitoring of transcranial MEPs provides the best method for assessing spinal cord integrity during complex spinal surgeries. MEPs are affected by pharmacological and physiological parameters. It is the responsibility of the spine surgeon and neuroanesthesia team to understand how they can best maintain high-quality MEP signals throughout surgery. Nevertheless, varying approaches to neuroanesthesia are seen in clinical practice.Methods
We identified 19 international expert spinal deformity treatment teams. A modified Delphi process with two rounds of surveying was performed. Greater than 50% agreement on the final statements was considered "agreement"; >75% agreement was considered "consensus."Results
Anesthesia regimens and protocols were obtained from the expert centers. There was a large amount of variability among centers. Two rounds of consensus surveying were performed, and all centers participated in both rounds of surveying. Consensus was obtained for 12 of 15 statements, and majority agreement was obtained for two of the remaining statements. Total intravenous anesthesia was identified as the preferred method of maintenance, with few centers allowing for low mean alveolar concentration of inhaled anesthetic. Most centers advocated for <150 μg/kg/min of propofol with titration to the lowest dose that maintains appropriate anesthesia depth based on awareness monitoring. Use of adjuvant intravenous anesthetics, including ketamine, low-dose dexmedetomidine, and lidocaine, may help to reduce propofol requirements without negatively effecting MEP signals.Conclusion
Spine surgeons and neuroanesthesia teams should be familiar with methods for optimizing MEPs during deformity and complex spinal cases. Although variability in practices exists, there is consensus among international spinal deformity treatment centers regarding best practices.Level of evidence
5.