Minimally Invasive versus Open Transforaminal Lumbar Interbody Fusion in Obese Patients: A Propensity Score-Matched Study.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVES: This study aimed to compare the clinical outcomes of obese patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and open TLIF. SUMMARY OF BACKGROUND DATA: The perioperative benefits of minimally invasive surgery in obese patients have been described. However, there is limited literature on the patient-reported outcomes (PROs), satisfaction and return to work following MIS-TLIF and open TLIF in this subgroup of patients. METHODS: Obese patients (BMI ≥30.0 kg/m2) who underwent a primary, one- to two-level open and MIS-TLIF were stratified and matched using propensity scoring. Operative time, length of stay and perioperative outcomes were recorded. Patient-reported outcomes (PROs) including Oswestry Disability Index, Short Form-36 Physical Component Score, Mental Component Score, Visual Analogue Scale for back pain and leg pain were compared at each postoperative time point. Achievement of minimal clinically important difference (MCID), patient satisfaction and return to work were also assessed. Revision procedures were recorded at mean 10±3.3 years follow-up. RESULTS: In total, 236 obese patients were included: 118 open TLIF and 118 MIS-TLIF. Length of stay was longer in the Open TLIF cohort and there was a trend towards a higher complication rate. However, there was no difference in operative time, transfusions or readmissions. Patients who underwent open TLIF reported worse ODI (P=0.043) and VAS leg pain at 2 years, although the latter did not reach statistical significance (P=0.095). Achievement of MCID for each PRO, patient satisfaction and return to work were also comparable. CONCLUSIONS: Obese patients who underwent MIS-TLIF had a shorter length of stay and improved functional disability at 2 years compared those who underwent open TLIF. However, a similar proportion achieved a clinical meaningful improvement. Patient satisfaction and return to work were also comparable at 2 years. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Long-Term Results of Minimally Invasive Transforaminal Lumbar Interbody Fusion in Elderly Patients: A 5-Year Follow-Up Study.

STUDY DESIGN: Retrospective review of prospective data. OBJECTIVES: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) may be beneficial for elderly patients due to decreased surgical morbidity and faster postoperative recovery. This study compared the clinical and radiological outcomes of MIS-TLIF in elderly patients and younger controls at minimum 5-year follow-up. METHODS: There were 120 patients who underwent single-level MIS-TLIF for degenerative spondylolisthesis. Elderly patients (≥70 years; n = 30) and controls (<70 years; n = 90) were matched 1:3 for demographics, comorbidities and preoperative patient-reported outcomes (PROs). The Oswestry Disability Index (ODI), 36-Item Short-Form Physical (SF-36 PCS) and Mental Component Summary (SF-36 MCS), Visual Analogue Scale (VAS) back pain, and VAS leg pain were compared at 6 months, 2 years and 5 years. Radiographic fusion, adjacent segment degeneration (ASD) and revision rates were assessed at mean 7.2 ± 2.0 years. RESULTS: Elderly patients had longer length of stay (4.7 ± 5.8 vs 3.3 ± 1.4 days, P = .035) and more readmissions (10% vs 1%, P = .019), but there was no difference in operative time, transfusions, complications or discharge disposition. All PROs were comparable at 5 years and satisfaction rates were similar (93% elderly vs 91% controls, P = .703). The rates of radiographic fusion in the control group and elderly group were similar (94% vs 97%, P = .605), as were the rates of ASD (40% vs 33%, P = .503). There were 3 revisions (3.3%) in the control group (2 for ASD, 1 for screw loosening) but none in the elderly group (P = .311). CONCLUSIONS: Elderly patients undergoing MIS-TLIF achieved similar improvements in pain, disability and quality of life that were sustained at 5 years.Level of Evidence: Level III, retrospective cohort study.

A Longer Duration of Myelopathy Symptoms is Associated With the Lack of Intraoperative Motor Evoked Potential Improvement During Decompressive Cervical Myelopathy Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: We aim to investigate the relationship between the intraoperative motor evoked potential (MEP) signal changes during surgical treatment of cervical myelopathy with postoperative functional outcomes and determine what factors correlate with MEP signal changes. SUMMARY OF BACKGROUND DATA: Intraoperative neurophysiologic monitoring with MEP for cervical cord decompression can potentially predict postoperative neurological complications. MATERIALS AND METHODS: We prospectively collected data from 114 consecutive cervical compressive myelopathy patients who underwent decompressive cervical spine surgery. Functional outcomes were measured preoperatively and postoperatively at the 6-month mark, using the modified Japanese Orthopedic Association score. RESULTS: Among the 114 patients, 87 patients showed significant MEP improvement, 1 patient with MEP degeneration, 3 patients with no change in MEP, and 23 patients with MEP change, but which eventually returned to baseline. Univariate analysis showed that patients with MEP improvement had similar 6-month functional and Japanese Orthopedic Association scores compared with patients who did not have MEP improvement. Critically, a longer duration of symptoms was shown to have a statistically significant relationship with patients who did not have MEP improvement on univariate analysis (49.2 wk in patients with no MEP improvement compared with 34.59 wk in patients with MEP improvement, P = 0.03) but this did not translate to differences in functional outcomes. There was also no statistically significant association between the functional outcome scores and demographics, surgical, or radiologic factors. CONCLUSIONS: Our study shows that the duration of symptoms is not attributed to lower functional outcomes but is associated with a lack of MEP improvement. LEVEL OF EVIDENCE: Level III.

Equipoise for Lateral Access Surgery.

OBJECTIVE: To investigate the use of lateral access surgery among surgeons from the Asia-Pacific region to determine equipoise for areas of contentious use. METHODS: A questionnaire was distributed to members of the Asia Pacific Spine Society. Surgeons were asked about their past experiences with lateral access surgery, including their advantages and disadvantages, specific surgical strategies, choices in implant-related factors, order of levels to operate on in multilevel reconstruction surgery, and postoperative complications. RESULTS: A total of 69 of 102 surgeons (67.6%) had performed lateral access surgery previously. In total, 56 participating surgeons (54.9%) agreed that anterior column reconstruction via lateral access is most of time superior to transforaminal lumbar interbody fusion and other techniques. Surgeons would consider laminectomy instead of indirect decompression in the presence of severe central or lateral recess stenosis, thickened ligamentum flavum, and facet joint hypertrophy. For the order of levels to operate on in multiple level reconstruction for deformity, where 1 stands for L3-L4 or higher, 2 stands for L4-L5, and 3 stands for L5-S1, 2-1-3 (28/95, 29.5%) was most common, followed by 1-2-3 (26/95, 27.4%), and 3-2-1 (21/95, 22.1%). CONCLUSIONS: Lateral access surgery is seeing greater use in the Asia-Pacific region, especially in upper middle- to high-income countries, whereas keenness of surgeons who practice in lower middle- to low-income countries can be improved by more training, resources, and reasonable cost. A high percentage of surgeons do not consider indirect decompression for spinal stenosis. There was no consensus on the order of levels in multiple level reconstruction for deformity.

Do the benefits of hook-hybrid construct justify their use over all-pedicle screws constructs in maintaining postoperative curve correction for adolescent idiopathic scoliosis patients from an Asian population?

STUDY DESIGN: Retrospective study. OBJECTIVE: (1) Compare outcomes of all-pedicle screws (PS) and hook-hybrid (H) constructs in adolescent idiopathic scoliosis (AIS) patients; and (2) investigate whether BMI, height or pedicle size may modify the effect of the type of surgical construct on the extent of curve decompensation. METHODS: AIS patients who underwent surgical fixation with H or PS constructs at a single tertiary institution were reviewed. Patients with implant density of at least 70% and 2-year follow-up were included. Demographic and perioperative data collected were age, sex, height, BMI, implant density and pedicle diameter. Cobb's angles and curve correction were compared preoperatively, postoperatively and at follow-up. RESULTS: In total, 59 patients were included. H group had a lower pedicle size at the highest level of construct and at T4 compared to PS group. Postoperatively, H group (30.2° ± 11.7°) and PS group (32.1° ± 10.4°) had similar correction (mean diff. 2.0°, p = 0.516). At 2-year follow-up, H group (1.6° ± 3.5°) and PS group (0.1° ± 2.8°) had similar curve deterioration (mean diff. 1.5°, p = 0.079). Uni- and multivariate analyses revealed that BMI and height were not associated with curve deterioration at 2-year follow-up among the H and PS groups. CONCLUSION: H constructs provided similar maintenance of curve correction at 2-year follow-up compared to PS constructs. BMI and Stature did not modify curve deterioration between both groups at follow-up. This study supports the use of H constructs when faced with difficult pedicle morphology associated with shorter stature as it provides comparable and satisfactory long-term maintenance of curve correction. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Risk Factors of Postoperative Shoulder Imbalance in Adolescent Idiopathic Scoliosis: The Role of Sagittal Spinopelvic Parameters and Upper Instrumented Vertebrae Selection.

STUDY DESIGN: This is a retrospective study. OBJECTIVE: To determine (1) the independent risk factors of postoperative shoulder imbalance (PSI) after adolescent idiopathic scoliosis (AIS) correction surgery; and (2) whether the level of upper instrumented vertebrae (UIV) affects postoperative shoulder balance. SUMMARY OF BACKGROUND DATA: PSI is an important outcome of AIS correction surgery as it influences a patient's appearance and satisfaction. However, risk factors for PSI remain controversial and there are currently no studies evaluating the effect of sagittal spinopelvic parameters on PSI. Previous studies on the relationship between the level of UIV and PSI have also reported conflicting results. MATERIALS AND METHODS: Sixty-nine AIS patients undergoing correction surgery at a single institution were retrospectively reviewed. Radiographic parameters were measured on anteroposterior and lateral x-rays preoperatively, immediate postoperatively, and 12 months postoperatively. At 1 year follow-up, patients were divided into 2 groups based on their radiographic shoulder height (RSH): (1) PSI group (RSH ≥20 mm) and (2) non-PSI group (RSH <20 mm). RESULTS: On multivariate regression analysis, a lower postoperative main thoracic curve (MTC) [odds ratio (OR): 0.702, 95% confidence interval (CI): 0.519-0.949, P=0.022], greater percentage correction of MTC (OR: 1.526, 95% CI: 1.049-2.220, P=0.027) and higher postoperative sacral slope (OR: 1.364, 95% CI: 1.014-1.834, P=0.040) were identified as independent risk factors of PSI. When preoperative, postoperative, and absolute change in shoulder parameters were compared across the level of UIV, no significant differences were found regardless of the radiographic shoulder parameter analyzed. CONCLUSIONS: Lower postoperative MTC, greater percentage correction of MTC and higher postoperative sacral slope were independent risk factors of PSI. Shoulder balance and symmetry were not affected by the level of UIV selected. Relative curve correction is a more important consideration than UIV to avoid PSI after AIS correction surgery. LEVEL OF EVIDENCE: III.

Shoulder Balance Following Correction Surgery for Adolescent Idiopathic Scoliosis: When Is It Achieved and Does the Type of Construct Matter?

STUDY DESIGN: This is a retrospective study. OBJECTIVE: This study aims to determine (1) when shoulder rebalancing occurs after adolescent idiopathic scoliosis (AIS) correction surgery and (2) whether shoulder asymmetry was influenced by the use of pedicle screws or hooks. SUMMARY OF BACKGROUND DATA: Postoperative shoulder imbalance is an important outcome of AIS correction surgery as it may influence a patient's appearance and satisfaction. MATERIALS AND METHODS: Seventy AIS patients undergoing AIS correction surgery at a single institution were retrospectively reviewed. Radiographic parameters were measured from anteroposterior x-rays at preoperative, immediate postoperative, 6 months postsurgery, and 12 months postsurgery. Shoulder parameters measured were: radiographic shoulder height (RSH), clavicle angle, coracoid height difference (CHD), and T1 tilt. The Cobb angle of the proximal thoracic curve, major thoracic curve, and thoracolumbar/lumbar curve. The percentage of correction was also calculated. RESULTS: Lateral shoulder asymmetry (RSH and CHD) changed significantly from preoperative to up to 6 months postsurgery. T1 tilt, a measure of medial shoulder asymmetry, did not change significantly. Postoperatively, the hook group attained significantly better shoulder balance than the screw group in terms of RSH and CHD up to 12 months postsurgery. However, the percentage correction of the major thoracic curve was significantly greater in the screw group than the hook group (hook: 62.2±18.4% vs. screw: 76.0±16.0%, P=0.007). CONCLUSIONS: Lateral shoulder rebalancing occurs up to 6 months after surgery. While thoracic pedicle screws offer greater correction of major AIS curves, hook constructs offer better postoperative shoulder symmetry. LEVEL OF EVIDENCE: III.

Intracerebral haemorrhage following spine surgery: a word of caution on the use of suction drains.

Intracranial haemorrhage (ICH) is a rare but devastating complication post spinal surgery. We present three cases of post spine surgery ICH that were associated with high drain outputs postoperatively. The first patient underwent C1-C6 instrumented fusion and C4-C6 decompression. 950 mls hemoserous fluid was drained via suction drain immediately postoperatively. He suffered cerebral hemorrhage with tonsillar herniation and was brain dead on the same night. The second patient underwent C1-T1 instrumented fusion with C3-C4 decompression. 400 mls hemoserous fluid was drained via suction drain shortly after skin closure. He suffered subdural hemorrhage, subarachnoid hemorrhage and intraventricular hemorrhage, with persistent neurologic deficits and required long-term institutionalised care. The third patient underwent L2-L4 decompression and instrumented fusion. 480 mls hemoserous fluid was drained via suction drain 2 hours postoperatively. He suffered subdural haemorrhage but eventually recovered fully. An excessive drain output, especially within first few minutes to hours postoperatively, may signify a CSFleak. Suction drains should be used with caution in these cases as negative suction in the presence of a dura tear increases risk of post spine surgery ICH. In these cases, the use of non-suction drains should be considered.

The Effect of Body Mass Index on Long-Term Patient-Reported Outcome Scores after Anterior Cervical Discectomy and Fusion in an Asian Population: A 2-Year Study.

STUDY DESIGN: Retrospective cohort study. PURPOSE: This study aims to analyze the relationship between body mass index (BMI) subjective patient-reported outcomes (PRO) after 1- and 2-level anterior cervical discectomy and fusion (ACDF). OVERVIEW OF LITERATURE: The prevalence of cervical spondylosis and ACDF in expected to continue rising among the aging population of Asia. Moreover, the prevalence of obesity is also increasing. However, limited information is available about the mechanism by which BMI affects PRO after ACDF. METHODS: Total 878 patients underwent ACDF between 2000 and 2015. After excluding patients with previous cervical instrumentation, >2 levels fused, missing BMI measurement, or neoplastic/trauma indication for surgery, 535 patients were included. The PRO measures of the Neck Disability Index, Numerical Pain Rating Scale (NPRS) for Neck Pain, NPRS for Limb Pain, American Academy of Orthopaedic Surgeons-Neurogenic Symptom Score, and Japanese Orthopaedic Association myelopathy score were used. Patients were grouped based on their preoperative BMI, as per the World Health Organization guidelines for Asian populations. PRO scores were collected preoperatively, at 6 months postoperatively, and 2 years postoperatively. A generalized linear model was used to analyze the relationship of BMI category with the individual score, accounting for several factors that are likely to affect the outcomes. RESULTS: Total 19 (3.4%) were underweight, 155 (28.0%) were normal weight, 112 (20.3%) were overweight, and 267 (48.3%) were obese. Patients across all BMI categories experienced significant and similar improvements in their postoperative PRO scores. There were no significant differences in the preoperative, 6-month postoperative, and 2-year postoperative PRO scores of the groups. Rate of reoperation was highest in patients with grade II obesity at 8.07%; however, the difference was not statistically significant. CONCLUSIONS: Irrespective of the BMI, all patients exhibited similar satisfactory outcomes following ACDF. The results support surgery in all subgroups of patients with symptomatic nerve compression in the cervical spine.

Poorer Preoperative Function Leads to Delayed Return to Work After Anterior Cervical Discectomy and Fusion for Degenerative Cervical Myelopathy.

BACKGROUND: The factors that affect return to work (RTW) after anterior cervical discectomy and fusion (ACDF) for degenerative cervical myelopathy (DCM) remain unclear, especially in a non-Workers' Compensation setting. We aimed to (1) identify factors that influence RTW in patients undergoing ACDF (2) determine if early RTW plays a role in functional outcomes, quality of life, and satisfaction. METHODS: Prospectively collected data of 103 working adults who underwent primary ACDF for DCM were retrospectively reviewed. Patients were stratified into 2 groups: early RTW (≤60 days, n = 42) and late RTW (>60 days, n = 61). RESULTS: The mean time taken to RTW was 34.7 and 134.9 days in the early and late RTW groups, respectively (P < 0.001). The early RTW group had significantly better preoperative Japan Orthopaedic Association (JOA) score and Neck Disability Index (NDI) (P < 0.05) and showed a trend toward higher 36-Item Short Form Physical Component Summary (PCS) (P = 0.071). The early RTW group also had significantly better postoperative JOA, NDI, and PCS at 6 months and less arm pain along with a trend toward better NDI at 2 years (P = 0.055). However, there was no difference in the change in outcome scores and a similar proportion in each group attained the minimal clinically important difference for each metric. At 2 years, 85.7% and 77.0% were satisfied in the early and late RTW groups, respectively (P = 0.275). CONCLUSIONS: While working adults that RTW later tend to have poorer function preoperatively and up to 2 years postoperatively, surgeons may reassure them that they will likely experience the same degree of clinical improvement and level of satisfaction after ACDF. LEVEL OF EVIDENCE: Level 3, therapeutic study.

The patient acceptable symptom state for the Oswestry Disability Index following single-level lumbar fusion for degenerative spondylolisthesis.

BACKGROUND CONTEXT: The patient acceptable symptom state (PASS) is a valuable tool for interpreting patient-reported outcomes. Previous studies have attempted to define the PASS in a heterogenous cohort with various lumbar spinal disorders and surgical procedures. PURPOSE: We aimed to determine the PASS threshold for the Oswestry Disability Index (ODI) specifically for patients undergoing lumbar fusion for spondylolisthesis-associated functional disability. STUDY DESIGN: Retrospective review of prospectively collected registry data. PATIENT SAMPLE: There were 692 patients who underwent primary single-level minimally invasive transforaminal lumbar interbody fusion for degenerative spondylolisthesis between 2006 and 2014. OUTCOME MEASURES: The ODI was collected pre-operatively, at 6 months and 2 years postoperatively. An anchor question was adapted from the NASS questionnaire, "How would you rate the overall results of your treatment?" while a validation question was taken from the same questionnaire, "Has the surgery for your back condition met your expectations so far?" METHODS: Responses to the anchor question were used to determine whether a PASS was achieved. Receiver operating characteristics curve analysis was performed to assess the ability of the ODI to discriminate between an acceptable/unacceptable symptom state as well as to define PASS thresholds. Sensitivity analyses were performed for different follow-up periods (6 months, 2 years), subgroups (by age, gender, BMI, and comorbidity burden), baseline ODI tertiles, and an alternate definition of PASS. RESULTS: In total, 529 of 692 (76%) patients completed 2-year follow-up, of which, 89% considered their symptom state to be acceptable. Areas under the curve (AUC) ranged from 0.81 to 0.90 for all receiver operating characteristics analyses, indicating that the ODI had an excellent discriminative ability. The PASS threshold was ≤18.09 at 6 months (AUC 0.81, sensitivity 77%, specificity 72%) and ≤15.27 at 2 years (AUC 0.86, sensitivity 79%, specificity 79%). These thresholds proved to be robust in the sensitivity analyses, showing minimal variation across different patient subgroups and baseline score tertiles. CONCLUSIONS: Patients with an ODI of ≤15.27 can be considered to have achieved a PASS after lumbar fusion for degenerative spondylolisthesis. These findings will help surgeons to contextualize a patient's functional recovery after lumbar spine surgery and enable researchers to define clinically relevant benchmarks when designing trials utilizing the ODI.

Surgical Excision of Thoracic Osteoblastoma with Secondary Aneurysmal Bone Cyst from a 12-Year-Old Child.

INTRODUCTION: Osteoblastoma is a primary benign tumour which commonly presents in the younger population during the second decade of life. However, more aggressive osteoblastomas may present with features of aneurysmal bone cyst, and these can occur at uncommon locations. CASE PRESENTATION: We report the case of a 12-year-old child having an osteoblastoma on the left side of T11 with secondary aneurysmal bone cyst presenting with neurological deficits and myelopathic symptoms. Surgical debulking of the lesion with decompression laminectomy and posterior instrumentation of the spine was performed. The child is currently recovering well with improvement of neurological deficits. DISCUSSION/CONCLUSION: Osteoblastoma with aneurysmal bone cyst of the thoracic spine is a rare condition with few reports in the literature, and surgical intervention with complete excision has been demonstrated here with recovery of neurological function.

Determination of the patient acceptable symptom state for the Japanese Orthopaedic Association Score in patients undergoing anterior cervical discectomy and fusion for cervical spondylotic myelopathy.

BACKGROUND CONTEXT: The patient acceptable symptom state (PASS) has gained attention as a valuable interpretation tool in spine research. While the PASS for the Japanese Orthopaedic Association (JOA) score has been recently proposed, previous analyses demonstrated a weak discriminative ability for the suggested threshold. PURPOSE: To define the PASS for the JOA score in patients undergoing anterior cervical discectomy and fusion (ACDF) for cervical spondylotic myelopathy (CSM). STUDY DESIGN: Retrospective review of prospectively collected registry data. PATIENT SAMPLE: 378 patients who underwent ACDF for cervical myelopathy between 2005 and 2014. OUTCOME MEASURES: The main outcome measure was the JOA score. The PASS anchor question was adapted from the NASS questionnaire, "How would you rate the overall results of your treatment?" and the validation question was adapted from same questionnaire, "Has the surgery for your neck condition met your expectation so far?" METHODS: Patients were assessed preoperatively, 6 months and 2 years postoperatively using the JOA. Responses to the anchor question were dichotomized and used as the external criterion in receiver operating characteristics (ROC) analysis to define thresholds on the JOA that corresponded to a PASS at 2 years postoperatively. Sensitivity analyses were carried out for various subgroups (based on age, gender, body mass index, comorbidities), preoperative myelopathy severity, time of follow-up (6 months and 2 years) and an alternate definition of PASS. RESULTS: Of the 378 patients, 312 (83%) completed 2-year follow-up, of which, 78.5% reported their current state as acceptable. The areas under the curve (AUC) for the ROCs were 0.72 to 0.83 for all analyses, indicating a good discriminative ability of the JOA when assessing if a satisfactory state was attained. The PASS threshold was ≥13.25 points at 6 months (AUC 0.74, sensitivity 78%, specificity 59%) and ≥14.25 points at 2 years (AUC 0.76, sensitivity 74%, specificity 66%). Sensitivity analyses revealed that the 14.25-point threshold on the JOA was robust. PASS responders were approximately 6 times more likely to be satisfied (adjusted OR 6.18, 95% CI 2.87-13.30) and 8 times more likely to have their expectation fulfilled (adjusted OR 8.23, 95% CI 3.81-17.77) compared with non-responders. CONCLUSIONS: This study validates the PASS threshold of 14.25 on the JOA in a robust analysis of a large cohort undergoing ACDF. This knowledge will enable clinicians to identify patients who have attained a satisfactory functional status after surgery for CSM and allow researchers to interpret studies utilizing the JOA from a patient-centered perspective.

A comparison of contiguous two-level anterior cervical discectomy and fusion using a structural allograft versus a Polyetheretherketone (PEEK) cage: the results of a three-year follow-up.

BACKGROUND: Allografts and polyetheretherketone (PEEK) cages are the two most commonly used materials in anterior cervical discectomy and fusion (ACDF). However, their effectiveness in two-level ACDF remains controversial. The primary aim of this retrospective study was to compare the clinical and radiological outcomes of two-level ACDF with plate fixation using either a structural allograft or a PEEK cage. METHODS: From 2010 to 2015, 88 consecutive patients underwent two-level ACDF, of whom 53 received an allograft and 35 patients received a PEEK cage. All PEEK cages were filled with local autografts. All clinical outcomes were prospectively collected before and six months and two years after surgery. Clinical efficacy was evaluated using a visual analogue scale for neck pain and limb pain, the Neck Pain and Disability Score, the Neck Disability Index, the Neurogenic Symptom Score, and the Japanese Orthopedic Association score. Radiological outcomes were assessed preoperatively, immediately after surgery, and at the final follow-up. RESULTS: A preoperative comparison revealed no difference between the two patient groups in terms of age, sex, body mass index, smoking status, preoperative symptoms, operation level, or follow-up (mean = 42.8 months). No differences in the improvements in clinical outcomes were observed between the two groups. Both groups showed significant improvement in mean disc height, segmental height, and segmental lordosis postoperatively. The fusion rate for the PEEK cage was 100% at both levels, while the fusion rate for the allograft group was 98.1% at the cephalad level and 94.2% at the caudad level (p > 0.05). Subsidence at the cephalad level occurred in 22.9% (8/35) of segments in the PEEK group and 7.7% (4/52) of segments in the allograft group (p = 0.057). At the caudal level, a higher incidence of cage subsidence was noted in the PEEK group than in the allograft group [37.1% (13/35) versus 15.4% (8/52)] (p = 0.02). Overall, subsidence was noted in 30% (21/70) of the PEEK group and in 11% (12/104) of the allograft group (p <  0.05). CONCLUSION: The use of PEEK cages resulted in a higher rate of subsidence in two-level ACDF than the use of allografts. Two-level ACDF using either allografts or PEEK cages resulted in similar clinical outcomes, radiological improvements in alignment and fusion rates.

Elderly Patients Undergoing Minimally Invasive Transforaminal Lumbar Interbody Fusion May Have Similar Clinical Outcomes, Perioperative Complications, and Fusion Rates As Their Younger Counterparts.

BACKGROUND: Although several studies have suggested that minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) may be especially beneficial in the elderly population due to lower operative morbidity and faster postoperative recovery, there are limited studies investigating the functional outcomes, quality of life, and satisfaction in elderly patients after MIS-TLIF. Furthermore, existing studies had substantial clinical, diagnostic, and surgical heterogeneity. QUESTIONS/PURPOSES: We asked if elderly patients could experience comparable (1) patient-reported pain, disability and quality of life, (2) perioperative complications, and (3) radiological fusion rates as their younger counterparts after MIS-TLIF. METHODS: Prospectively collected registry data of patients undergoing primary, single-level, MIS-TLIF for degenerative spondylolisthesis between 2012 and 2014 were reviewed. We included 168 patients, 39 of whom were at least 70 years old. Of the 129 patients younger than 70 years old, propensity-score matching was used to select 39 younger controls with adjustment for sex, BMI, American Society of Anesthesiologists score, and baseline clinical outcomes. Perioperative complications and radiologic data were compared. RESULTS: There was no difference in back pain (mean difference -0.3 [95% confidence interval -1.0 to 0.5]; p = 0.52); leg pain (mean difference -0.1 [95% CI to 0.6-0.5]; p = 0.85); Oswestry Disability Index (mean difference -2.9 [95% CI -8.0 to 2.2]; p = 0.26); and SF-36 physical (mean difference 3.0 [95% CI -0.7 to 6.8]; p = 0.107); and mental component summary (mean difference 1.9 [95% CI -4.5 to 8.2]; p = 0.56); up to 2 years postoperatively; 85% of younger patients and 85% of elderly patients were satisfied (p > 0.99) while 87% and 80%, respectively, had fulfilled expectations (p = 0.36). Four perioperative adverse events occurred in each group. There was also no difference in the rate of fusion (87% in younger patients and 90% in elderly patients; p = 0.135). CONCLUSIONS: When clinical and surgical heterogeneity were minimized, elderly patients undergoing minimally invasive transforaminal lumbar interbody fusion not only had comparable rates of perioperative complications but also experienced similar improvements in pain, function, and quality of life. A high rate of satisfaction was achieved. LEVEL OF EVIDENCE: Level II, prognostic study.

Sagittally Balanced Degenerative Spondylolisthesis Patients With Increased Sacral Slope and Greater Lumbar Lordosis Experience Less Back Pain After Short-Segment Lumbar Fusion Surgery.

STUDY DESIGN: A retrospective review of prospectively collected registry data. OBJECTIVES: (1) Examine functional outcomes of patients with postoperative sacral slope (SS)<30 degrees versus SS≥30 degrees after single-level transforaminal lumbar interbody fusion (TLIF) for degenerative spondylolisthesis (DS); (2) determine the factors associated with SS at the last follow-up. SUMMARY OF BACKGROUND DATA: Few studies have examined the relationship between spinopelvic parameters and functional outcomes in patients with DS undergoing short-segment TLIF. Although SS of 30 degrees has been proposed as the ideal spinopelvic parameter for eliminating residual pain and disability in adult spinal deformity, the ideal value for DS remains unknown. METHODS: Prospectively collected registry data of 63 patients who underwent single-level L4-L5 open TLIF with sagittal realignment for DS were reviewed. Pelvic incidence, lumbar lordosis (LL), pelvic tilt, SS, listhesis excursion, and Bridwell fusion grading were recorded. Patients were stratified into SS<30 degrees (n=26) or SS≥30 degrees (n=37) at the last follow-up. All patients were assessed preoperatively and postoperatively at 2 years. Receiver operating characteristics curve analysis was used to assess the relationship between expectation fulfillment and change in SS. RESULTS: Patients with SS≥30 degrees had significantly lower back pain at 2 years (P<0.04). There were no differences in leg pain or outcome scores (Oswestry Disability Index, Short-Form 36 Physical, and Mental Component Summaries), although there was a trend towards better outcomes and higher satisfaction/expectation fulfillment in patients with SS≥30 degrees. The SS≥30 degrees group had a higher preoperative LL (P=0.04) and SS (P<0.01). Preoperative SS was correlated with SS (R=0.71, P<0.01) and LL (R=0.51, P<0.01) at the last follow-up. The area under the curve for change in SS was 0.680 (95% confidence interval, 0.453-0.907) for predicting expectation fulfillment at 2 years. CONCLUSIONS: Patients with increased SS (≥30 degrees) experienced less back pain after short-segment lumbar fusion surgery. This was associated with increased LL postoperatively, indicating better sagittal balance.

Severity of Preoperative Myelopathy Symptoms Affects Patient-reported Outcomes, Satisfaction, and Return to Work After Anterior Cervical Discectomy and Fusion for Degenerative Cervical Myelopathy.

STUDY DESIGN: Retrospective review of prospectively-collected registry data. OBJECTIVE: To compare the patient-reported outcomes, satisfaction, and return to work among a large cohort of patients stratified by preoperative myelopathy severity undergoing Anterior Cervical Discectomy and Fusion (ACDF) for Degenerative Cervical Myelopathy. SUMMARY OF BACKGROUND DATA: Recent clinical practice guidelines noted a lack of studies stratifying their sample based on preoperative disease severity. The benefits of early surgical intervention for patients with mild myelopathy remain uncertain. METHODS: A prospectively-maintained registry was retrospectively reviewed for all patients who underwent primary ACDF for Degenerative Cervical Myelopathy. Patients were stratified based on severity of preoperative myelopathy symptoms according to the Japanese Orthopaedic Association (JOA) scale: mild (>13), moderate (9-13), or severe (<9). Patients were prospectively followed for at least 2 years. RESULTS: In total, 219 patients were included: 74 mild, 94 moderate, and 51 severe cases. The mild group had significantly better Neurogenic Symptoms (NS), Neck Disability Index (NDI), SF-36 Physical (PCS), and Mental Component Summary at baseline (P < 0.05). Neck and arm pain scores were similar at all time points. At 2 years, the severe group still had significantly worse patient-reported outcomes and lower rates of satisfaction, expectation fulfilment and return to work. However, they had significantly greater improvement in JOA, Neurogenic Symptoms, NDI, PCS, and Mental Component Summary, and a larger proportion attained minimal clinically important difference (MCID) for NDI and PCS. All three groups had similar proportions attaining MCID for JOA. CONCLUSION: Patients with severe myelopathy experienced a greater improvement after ACDF. Although fewer patients attained MCID, early surgical intervention for patients with mild myelopathy should also be considered, as this may allow patients to maintain their higher functional status. They also had high rates of postoperative satisfaction and return to work. The clinical trajectory outlined in this study may provide valuable prognostic information for patients. LEVEL OF EVIDENCE: 3.

Management of the neglected and healed bilateral cervical facet dislocation.

INTRODUCTION: There is limited literature on the management of neglected healed (fused) bilateral cervical facet dislocation. The authors report a case of a middle aged male who developed a bilateral facet dislocation but only sought treatment 14 months post injury when he experienced pain and deformity in the cervical spine. CASE REPORT: A 42-year-old male was pushed into a 1.2-m pool by accident and hit his head on the bottom. He immediately felt a sharp pain in his neck but was able to get out of the pool by himself and at the emergency department was found to have no neurological deficit. Standard trauma radiographs were performed and a grade 1 anterolisthesis of C4 on C5 was observed without any facet subluxation or dislocation. An emergent Magnetic Resonance Imaging (MRI) of the cervical spine confirmed X-ray results and in addition demonstrated injury to the posterior ligament complex and a broad-based posterior disc bulge. Computed Tomography (CT) scans revealed no facet dislocation or fractures. Unfortunately, the patient failed to come for his follow-up visits and at 14 months post injury, represented with pain and deformity with impairment of horizontal gaze. Computed tomography and MRI demonstrated a fused (bony) bilateral facet dislocation at C4/5. A cervical spine reconstruction consisting of a posterior-anterior-posterior approach was performed to address both the deformity and the pain. At 32-month follow-up, the patient remains well with no neurological symptoms, minimal neck pain and successful fusion. CONCLUSION: Current literature does not offer a clear solution to the management of healed neglected bilateral cervical facet dislocation. The presence of circumferential bony fusion around the deformity necessitates a posterior and anterior release and subsequent stabilization to address this complex problem. We also wish to highlight the order of the reconstructive approach and the need to recognize instability of the cervical spine despite normal CT scans in order to prevent late deformity.

Fusion and subsidence rate of stand alone anterior lumbar interbody fusion using PEEK cage with recombinant human bone morphogenetic protein-2.

INTRODUCTION: Anterior lumbar interbody fusion (ALIF) is an established treatment for structural instability associated with symptomatic disk degeneration (SDD). Stand-alone ALIF offers many advantages, however, it may increase the risk of non-union. Recombinant human bone morphogenetic protein-2 (BMP-2) may enhance fusion rate but is associated with postoperative complication. The optimal dose of BMP-2 remains unclear. This study assessed the fusion and subsidence rates of stand-alone ALIF using the SynFix-LR interbody cage with 6 ml/level of BMP-2. METHODS: Thirty-two ALIF procedures were performed by a single surgeon in 25 patients. Twenty-five procedures were performed for SDD without spondylolisthesis (SDD group) and seven procedures were performed for SDD with grade-I olisthesis (SDD-olisthesis group). Patients were followed-up for a mean of 17 ± 6 months. RESULTS: Solid fusion was achieved in 29 cases (90.6 %) within 6 months postoperatively. Five cases of implant subsidence were observed (16 %). Four of these occurred in the SDD-olisthesis group and one occurred in the SDD group (57 % vs. 4 % respectively; p = 0.004). Three cases of subsidence failed to fuse and required revision. The body mass index of patients with olisthesis who developed subsidence was higher than those who did not develop subsidence (29 ± 2.6 vs. 22 ± 6.5 respectively; p = 0.04). No BMP-2 related complications occurred. CONCLUSION: The overall fusion rate of stand-alone ALIF using the SynFix-LR system with BMP-2 was 90.6 %, comparable with other published series. No BMP-2 related complication occurred at a dose of 6 mg/level. Degenerative spondylolisthesis and obesity seemed to increase the rate of implant subsidence, and thus we believe that adding posterior fusion for these cases should be considered.