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Pooya Javidan, Nima Kabirian, Gregory M. Mundis Jr. and Behrooz A. Akbarnia

The authors report a case of progressive congenital kyphoscoliosis in which the patient, a boy, originally underwent combined anterior and instrumented posterior spinal fusion at the age of 7 years and 3 months. Early proximal junctional kyphosis and implant failure mandated proximal extension of implants with 2 new rods connected to the old caudad short rods. At the 3-year follow-up, clinical and CT assessment revealed a thoracolumbar pseudarthrosis for which the patient underwent a 2-stage procedure without complication. Recordings of somatosensory evoked potentials intraoperatively were normal. Twelve hours after surgery, his neurological status started to progressively deteriorate. The patient was brought to the operating room, and the initially achieved correction was reversed by an apex-only exposure of the 4-rod system. After surgery the patient started to show progressive improvement in his neurological function. A final myelography was performed and showed free passage of the dye without evidence of obstruction. Clinically, the patient continued to improve and at his 3-month follow-up had near-complete resolution of his neurological deficits. Findings on his physical examination were normal at the final 12-year follow-up.

Despite normal findings on intraoperative neuromonitoring, a delayed neurological deficit can occur after complex spine reconstruction. Preoperative risk assessment, surgical approach, and instrumentation deserve careful attention. Advantages of a 4-rod construct are discussed in this case.

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Pooria Hosseini, Gregory M. Mundis Jr., Robert K. Eastlack, Ramin Bagheri, Enrique Vargas, Stacie Tran and Behrooz A. Akbarnia

OBJECTIVE

Sagittal malalignment decreases patients’ quality of life and may require surgical correction to achieve realignment goals. High-risk posterior-based osteotomy techniques are the current standard treatment for addressing sagittal malalignment. More recently, anterior lumbar interbody fusion, anterior column realignment (ALIF ACR) has been introduced as an alternative for correction of sagittal deformity. The objective of this paper was to report clinical and radiographic results for patients treated using the ALIF-ACR technique.

METHODS

A retrospective study of 39 patients treated with ALIF ACR was performed. Patient demographics, operative details, radiographic parameters, neurological assessments, outcome measures, and preoperative, postoperative, and mean 1-year follow-up complications were studied.

RESULTS

The patient population comprised 39 patients (27 females and 12 males) with a mean follow-up of 13.3 ± 4.7 months, mean age of 66.1 ± 11.6 years, and mean body mass index of 27.3 ± 6.2 kg/m2. The mean number of ALIF levels treated was 1.5 ± 0.5. Thirty-three (84.6%) of 39 patients underwent posterior spinal fixation and 33 (84.6%) of 39 underwent posterior column osteotomy, of which 20 (60.6%) of 33 procedures were performed at the level of the ALIF ACR. Pelvic tilt, sacral slope, and pelvic incidence were not statistically significantly different between the preoperative and postoperative periods and between the preoperative and 1-year follow-up periods (except for PT between the preoperative and 1-year follow-up, p = 0.018). Sagittal vertical axis, T-1 spinopelvic inclination, lumbar lordosis, pelvic incidence–lumbar lordosis mismatch, intradiscal angle, and motion segment angle all improved from the preoperative to postoperative period and the preoperative to 1-year follow-up (p < 0.05). The changes in motion segment angle and intradiscal angle achieved in the ALIF-ACR group without osteotomy compared with the ALIF-ACR group with osteotomy at the level of ACR were not statistically significant. Total visual analog score, Oswestry Disability Index, and Scoliosis Research Society–22 scores all improved from preoperative to postoperative and preoperative to 1-year follow-up. Fourteen patients (35.9%) experienced 26 complications (15 major and 11 minor). Eleven patients required reoperation. The most common complication was proximal junctional kyphosis (6/26 complications, 23%) followed by vertebral body/endplate fracture (3/26, 12%).

CONCLUSIONS

This study showed satisfactory radiographic and clinical outcomes at the 1-year follow-up. Proximal junctional kyphosis was the most common complication followed by fracture, complications that are commonly associated with sagittal realignment surgery and may not be mitigated by the anterior approach.

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Juan S. Uribe, Donald A. Smith, Elias Dakwar, Ali A. Baaj, Gregory M. Mundis, Alexander W. L. Turner, G. Bryan Cornwall and Behrooz A. Akbarnia

Object

In the surgical treatment of spinal deformities, the importance of restoring lumbar lordosis is well recognized. Smith-Petersen osteotomies (SPOs) yield approximately 10° of lordosis per level, whereas pedicle subtraction osteotomies result in as much as 30° increased lumbar lordosis. Recently, selective release of the anterior longitudinal ligament (ALL) and placement of lordotic interbody grafts using the minimally invasive lateral retroperitoneal transpsoas approach (XLIF) has been performed as an attempt to increase lumbar lordosis while avoiding the morbidity of osteotomy. The objective of the present study was to measure the effect of the selective release of the ALL and varying degrees of lordotic implants placed using the XLIF approach on segmental lumbar lordosis in cadaveric specimens between L-1 and L-5.

Methods

Nine adult fresh-frozen cadaveric specimens were placed in the lateral decubitus position. Lateral radiographs were obtained at baseline and after 4 interventions at each level as follows: 1) placement of a standard 10° lordotic cage, 2) ALL release and placement of a 10° lordotic cage, 3) ALL release and placement of a 20° lordotic cage, and 4) ALL release and placement of a 30° lordotic cage. All four cages were implanted sequentially at each interbody level between L-1 and L-5. Before and after each intervention, segmental lumbar lordosis was measured in all specimens at each interbody level between L-1 and L-5 using the Cobb method on lateral radiography.

Results

The mean baseline segmental lordotic angles at L1–2, L2–3, L3–4, and L4–5 were –3.8°, 3.8°, 7.8°, and 22.6°, respectively. The mean lumbar lordosis was 29.4°. Compared with baseline, the mean postimplantation increase in segmental lordosis in all levels combined was 0.9° in Intervention 1 (10° cage without ALL release); 4.1° in Intervention 2 (ALL release with 10° cage); 9.5° in Intervention 3 (ALL release with 20° cage); and 11.6° in Intervention 4 (ALL release with 30° cage). Foraminal height in the same sequence of conditions increased by 6.3%, 4.6%, 8.8% and 10.4%, respectively, while central disc height increased by 16.1%, 22.3%, 52.0% and 66.7%, respectively. Following ALL release and placement of lordotic cages at all 4 lumbar levels, the average global lumbar lordosis increase from preoperative lordosis was 3.2° using 10° cages, 12.0° using 20° cages, and 20.3° using 30° cages. Global lumbar lordosis with the cages at 4 levels exhibited a negative correlation with preoperative global lordosis (10°, R = −0.756; 20°, −0.730; and 30°, R = −0.437).

Conclusions

Combined ALL release and placement of increasingly lordotic lateral interbody cages leads to progressive gains in segmental lordosis in the lumbar spine. Mean global lumbar lordosis similarly increased with increasingly lordotic cages, although the effect with a single cage could not be evaluated. Greater global lordosis was achieved with smaller preoperative lordosis. The mean maximum increase in segmental lordosis of 11.6° followed ALL release and placement of the 30° cage.

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Amir Ahmadian, Sean Verma, Gregory M. Mundis Jr., Rod J. Oskouian Jr., Donald A. Smith and Juan S. Uribe

Object

In this study the authors report on the clinical outcomes, safety, and efficacy of lateral retroperitoneal transpsoas minimally invasive surgery–lumbar interbody fusion (MIS-LIF) at the L4–5 disc space in patients with spondylolisthesis. This approach has become an increasingly popular means of fusion. Its most frequent complication is lumbar plexus injury. Reported complication rates at the L4–5 disc space vary widely in the literature, bringing into question the safety of MIS-LIF for the L4–5 region, especially in patients with spondylolisthesis.

Methods

The authors retrospectively reviewed prospectively acquired multicenter databases of patients with Grade I and II L4–5 spondylolisthesis who had undergone elective MIS-LIF between 2008 and 2011. Clinical follow-up had been scheduled for 1, 3, 6, 12, and 24 months postoperatively. Outcome measures included estimated blood loss, operative time, length of hospital stay, integrity of construct, complications, fusion rates, visual analog scale (VAS), Oswestry Disability Index (ODI), and 36-Item Short Form Health Survey (SF-36).

Results

Eighty-four patients with L4–5 MIS-LIF were identified, 31 of whom met the study inclusion criteria: 26 adults with Grade I and 5 adults with Grade II L4–5 spondylolisthesis who had undergone elective MIS-LIF and subsequent posterior percutaneous pedicle screw fixation without surgical manipulation of the posterior elements (laminectomy, foraminotomy, facetectomy). The study cohort consisted of 9 males (29%) and 22 females (71%) with an average age of 61.5 years. The mean total blood loss was 94 ml (range 20–250 ml). The mean hospital stay and follow-up were 3.5 days and 18.2 months, respectively. The average score on the ODI improved from 50.4 preoperatively to 30.9 at the last follow-up (p < 0.0001). The SF-36 score improved from 38.1 preoperatively to 59.5 at the last follow-up (p < 0.0001). The VAS score improved from 69.9 preoperatively to 38.7 at the last follow-up (p < 0.0001). No motor weakness or permanent deficits were documented in any patient. Correction of deformity did not have any neurological complications. All patients had improvement in anterolisthesis. Residual postoperative listhesis across cases was noted in 4 patients (12.9%). Transient anterior thigh numbness (Sensory Dermal Zone III) was noted in 22.5% of patients.

Conclusions

With its established surgical corridors through the retroperitoneum and psoas muscle, the MIS-LIF combined with posterior percutaneous pedicle screw fixation/reduction is a safe, reproducible, and effective technique for patients with symptomatic degenerative spondylolisthesis at the L4–5 vertebral segment.

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The comprehensive anatomical spinal osteotomy and anterior column realignment classification

Presented at the 2018 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

Juan S. Uribe, Frank Schwab, Gregory M. Mundis Jr., David S. Xu, Jacob Januszewski, Adam S. Kanter, David O. Okonkwo, Serena S. Hu, Deviren Vedat, Robert Eastlack, Pedro Berjano and Praveen V. Mummaneni

OBJECTIVE

Spinal osteotomies and anterior column realignment (ACR) are procedures that allow preservation or restoration of spine lordosis. Variations of these techniques enable different degrees of segmental, regional, and global sagittal realignment. The authors propose a comprehensive anatomical classification system for ACR and its variants based on the level of technical complexity and invasiveness. This serves as a common language and platform to standardize clinical and radiographic outcomes for the utilization of ACR.

METHODS

The proposed classification is based on 6 anatomical grades of ACR, including anterior longitudinal ligament (ALL) release, with varying degrees of posterior column release or osteotomies. Additionally, a surgical approach (anterior, lateral, or posterior) was added. Reliability of the classification was evaluated by an analysis of 16 clinical cases, rated twice by 14 different spine surgeons, and calculation of Fleiss kappa coefficients.

RESULTS

The 6 grades of ACR are as follows: grade A, ALL release with hyperlordotic cage, intact posterior elements; grade 1 (ACR + Schwab grade 1), additional resection of the inferior facet and joint capsule; grade 2 (ACR + Schwab grade 2), additional resection of both superior and inferior facets, interspinous ligament, ligamentum flavum, lamina, and spinous process; grade 3 (ACR + Schwab grade 3), additional adjacent-level 3-column osteotomy including pedicle subtraction osteotomy; grade 4 (ACR + Schwab grade 4), 2-level distal 3-column osteotomy including pedicle subtraction osteotomy and disc space resection; and grade 5 (ACR + Schwab grade 5), complete or partial removal of a vertebral body and both adjacent discs with or without posterior element resection. Intraobserver and interobserver reliability were 97% and 98%, respectively, across the 14-reviewer cohort.

CONCLUSIONS

The proposed anatomical realignment classification provides a consistent description of the various posterior and anterior column release/osteotomies. This reliability study confirmed that the classification is consistent and reproducible across a diverse group of spine surgeons.

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Kseniya Slobodyanyuk, Caroline E. Poorman, Justin S. Smith, Themistocles S. Protopsaltis, Richard Hostin, Shay Bess, Gregory M. Mundis Jr., Frank J. Schwab and Virginie Lafage

Object

The goal of this study was to determine the outcome and risk factors in patients with adult spinal deformity (ASD) who elected to receive nonoperative care.

Methods

In this retrospective study the authors reviewed a nonoperative branch of the International Spine Study Group database, derived from 10 sites across the US. Specific inclusion criteria included nonoperative treatment for ASD and the availability of Scoliosis Research Society (SRS)-22 scores and radiographic data at baseline (BL) and at 1-year (1Y) follow-up. Health-related quality of life measures were assessed using the SRS-22 and radiographic data. Changes in SRS-22 scores were evaluated by domain and expressed in number of minimum clinically important differences (MCIDs) gained or lost; BL and 1Y scores were also compared with age- and sex-matched normative references.

Results

One hundred eighty-nine patients (mean age 53 years, 86% female) met inclusion criteria. Pain was the domain with the largest offset for 43% of patients, followed by the Appearance (23%), Activity (18%), and Mental (15%) domains. On average, patients improved 0.3 MCID in Pain over 1Y, without changes in Activity or Appearance. Baseline scores significantly impacted 1Y outcomes, with up to 85% of patients in the mildest category of deformity being classified as < 1 MCID of normative reference at 1Y, versus 0% of patients with the most severe initial deformity. Baseline radiographic parameters did not correlate with outcome.

Conclusions

Patients who received nonoperative care are significantly more disabled than age- and sex-matched normative references. The likelihood for a patient to reach SRS scores similar to the normative reference at 1Y decreases with increased BL disability. Nonoperative treatment is a viable option for certain patients with ASD, and up to 24% of patients demonstrated significant improvement over 1Y with nonoperative care.

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Khoi D. Than, Praveen V. Mummaneni, Kelly J. Bridges, Stacie Tran, Paul Park, Dean Chou, Frank La Marca, Juan S. Uribe, Todd D. Vogel, Pierce D. Nunley, Robert K. Eastlack, Neel Anand, David O. Okonkwo, Adam S. Kanter and Gregory M. Mundis Jr.

OBJECTIVE

High-quality studies that compare outcomes of open and minimally invasively placed pedicle screws for adult spinal deformity are needed. Therefore, the authors compared differences in complications from a circumferential minimally invasive spine (MIS) surgery and those from a hybrid surgery.

METHODS

A retrospective review of a multicenter database of patients with spinal deformity who were treated with an MIS surgery was performed. Database inclusion criteria included an age of ≥ 18 years and at least 1 of the following: a coronal Cobb angle of > 20°, a sagittal vertical axis of > 5 cm, a pelvic incidence–lumbar lordosis angle of > 10°, and/or a pelvic tilt of > 20°. Patients were propensity matched according to the levels instrumented.

RESULTS

In this database, a complete data set was available for 165 patients, and after those who underwent 3-column osteotomy were excluded, 137 patients were available for analysis; 76 patients remained after propensity matching (MIS surgery group 38 patients, hybrid surgery group 38 patients). The authors found no difference in demographics, number of levels instrumented, or preoperative and postoperative radiographic results. At least 1 complication was suffered by 55.3% of patients in the hybrid surgery group and 44.7% of those in the MIS surgery group (p = 0.359). Patients in the MIS surgery group had significantly fewer neurological, operative, and minor complications than those in the hybrid surgery group. The reoperation rates in both groups were similar. The most common complication category for the MIS surgery group was radiographic and for the hybrid surgery group was neurological. Patients in both groups experienced postoperative improvement in their Oswestry Disability Index and visual analog scale (VAS) back and leg pain scores (all p < 0.05); however, MIS surgery provided a greater reduction in leg pain according to VAS scores.

CONCLUSIONS

Overall complication rates in the MIS and hybrid surgery groups were similar. MIS surgery resulted in significantly fewer neurological, operative, and minor complications. Reoperation rates in the 2 groups were similar, and despite complications, the patients reported significant improvement in their pain and function.

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Pierce D. Nunley, Gregory M. Mundis Jr., Richard G. Fessler, Paul Park, Joseph M. Zavatsky, Juan S. Uribe, Robert K. Eastlack, Dean Chou, Michael Y. Wang, Neel Anand, Kelly A. Frank, Marcus B. Stone, Adam S. Kanter, Christopher I. Shaffrey, Praveen V. Mummaneni and the International Spine Study Group

OBJECTIVE

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.

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Christopher P. Ames, Justin S. Smith, Justin K. Scheer, Christopher I. Shaffrey, Virginie Lafage, Vedat Deviren, Bertrand Moal, Themistocles Protopsaltis, Praveen V. Mummaneni, Gregory M. Mundis Jr., Richard Hostin, Eric Klineberg, Douglas C. Burton, Robert Hart, Shay Bess, Frank J. Schwab and the International Spine Study Group

Object

Cervical spine osteotomies are powerful techniques to correct rigid cervical spine deformity. Many variations exist, however, and there is no current standardized system with which to describe and classify cervical osteotomies. This complicates the ability to compare outcomes across procedures and studies. The authors' objective was to establish a universal nomenclature for cervical spine osteotomies to provide a common language among spine surgeons.

Methods

A proposed nomenclature with 7 anatomical grades of increasing extent of bone/soft tissue resection and destabilization was designed. The highest grade of resection is termed the major osteotomy, and an approach modifier is used to denote the surgical approach(es), including anterior (A), posterior (P), anterior-posterior (AP), posterior-anterior (PA), anterior-posterior-anterior (APA), and posterior-anterior-posterior (PAP). For cases in which multiple grades of osteotomies were performed, the highest grade is termed the major osteotomy, and lower-grade osteotomies are termed minor osteotomies. The nomenclature was evaluated by 11 reviewers through 25 different radiographic clinical cases. The review was performed twice, separated by a minimum 1-week interval. Reliability was assessed using Fleiss kappa coefficients.

Results

The average intrarater reliability was classified as “almost perfect agreement” for the major osteotomy (0.89 [range 0.60–1.00]) and approach modifier (0.99 [0.95–1.00]); it was classified as “moderate agreement” for the minor osteotomy (0.73 [range 0.41–1.00]). The average interrater reliability for the 2 readings was the following: major osteotomy, 0.87 (“almost perfect agreement”); approach modifier, 0.99 (“almost perfect agreement”); and minor osteotomy, 0.55 (“moderate agreement”). Analysis of only major osteotomy plus approach modifier yielded a classification that was “almost perfect” with an average intrarater reliability of 0.90 (0.63–1.00) and an interrater reliability of 0.88 and 0.86 for the two reviews.

Conclusions

The proposed cervical spine osteotomy nomenclature provides the surgeon with a simple, standard description of the various cervical osteotomies. The reliability analysis demonstrated that this system is consistent and directly applicable. Future work will evaluate the relationship between this system and health-related quality of life metrics.

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Micheal Raad, Brian J. Neuman, Amit Jain, Hamid Hassanzadeh, Peter G. Passias, Eric Klineberg, Gregory M. Mundis Jr., Themistocles S. Protopsaltis, Emily K. Miller, Justin S. Smith, Virginie Lafage, D. Kojo Hamilton, Shay Bess, Khaled M. Kebaish, Daniel M. Sciubba and the International Spine Study Group

OBJECTIVE

Given the recent shift in health care toward quality reporting requirements and a greater emphasis on a cost-quality approach, patient stratification with respect to long-term outcomes and the use of health care resources is of increasing value. Stratification tools may be effective if they are simple and evidence based. The authors hypothesize that preoperative patient-reported activity levels might independently predict postoperative outcomes in patients with adult spinal deformity.

METHODS

This is a retrospective cohort. A total of 575 patients in a prospective adult spinal deformity surgical database were identified with complete data regarding the preoperative level of activity. Answers to question 5 of the Scoliosis Research Society-22r Patient Questionnaire (SRS-22r) were used to stratify patients into active and inactive groups. Outcomes were length of hospital stay (LOS), level of activity, and reaching the minimum clinically important difference (MCID) for SRS-22r domains and the Physical Component Summary (PCS) of the SF-36 at 2 years postoperatively. The 2 groups were compared with respect to several potential confounders. Covariates with p < 0.1 were controlled for. The impact of activity on LOS was assessed using multivariate negative binomial regression analysis. Multivariate logistic regression models additionally controlling for the respective baseline health-related quality of life (HRQOL) scores were used to assess the association between preoperative activity levels and reaching the MCID at 2 years postoperatively.

RESULTS

A total of 420 (73%) of the 575 patients who met the inclusion criteria had complete data at 2 years postoperatively. The inactive group was more likely to be significantly older, have a higher Charlson Comorbidity Index, worse baseline radiographic deformity, and greater correction of most radiographic parameters. After controlling for possible confounders, the active group had a significantly shorter LOS (incidence risk ratio 0.91, p = 0.043). After adding respective baseline HRQOL scores to the models, active patients were significantly more likely to reach the MCID for the SRS-22r pain domain (OR 1.72, p = 0.026) and PCS (OR 1.94, p = 0.013). Active patients were also significantly more likely to be active at 2 years postoperatively on multivariate analysis (OR 8.94, p < 0.001).

CONCLUSIONS

The authors’ results show that patients who belong to the inactive group are likely to have a longer LOS and lower odds of reaching the MCID in HRQOL or being active at 2 years postoperatively. Inquiring about patients’ preoperative activity levels might be a reliable and simple stratification tool in terms of long- and short-term outcomes in ASD patients.