Effect of Clinical and Radiographic Degenerative Spondylolisthesis Classification on Patient-reported Outcomes and Spinopelvic Parameters for Patients With Single-level L4-L5 Degenerative Spondylolisthesis After Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To determine whether preoperative clinical and radiographic degenerative spondylolisthesis (CARDS) classification is associated with differences in patient-reported outcomes and spinopelvic parameters after posterior decompression and fusion for L4-L5 degenerative spondylolisthesis (DS).

SUMMARY

The CARDS classification for lumbar DS, an alternative to the Meyerding system, considers additional radiographic findings such as disc space collapse and segmental kyphosis and stratifies DS into 4 radiographically distinct classes. Although CARDS has been shown to be a reliable and reproducible method for classifying DS, very few studies have assessed whether the CARDS types represent distinct clinical entities.

PATIENTS AND METHODS

A retrospective cohort analysis was conducted on patients with L4-L5 DS who underwent posterior lumbar decompression and fusion. Changes in spinopelvic alignment and patient-reported outcomes measures, including recovery ratios and percentage of patients achieving the minimal clinically important difference, were compared among patients in each CARDS classification 1-year postoperatively using analysis of variance or Kruskal-Wallis H with Dunn post hoc analysis. Multiple linear regression determined whether CARDS groups significantly predicted patient-reported outcomes measures, lumbar lordosis (LL), and pelvic incidence-lumbar lordosis mismatch (PI-LL) while controlling for demographic and surgical characteristics.

RESULTS

Preoperative type B spondylolisthesis predicted decreased improvement in "physical component and mental component score of the short form-12" compared with type A spondylolisthesis (β-coefficient = -5.96, P = 0.031) at 1 year. Significant differences were found between CARDS groups with regards to ΔLL (A: -1.63 degrees vs B: -1.17 degrees vs C: 2.88 degrees vs D: 3.19 degrees, P = 0.010) and ΔPI-LL (A: 1.02 degrees vs B: 2.09 degrees vs C: -2.59 degrees vs D: -3.70 degrees, P = 0.012). Preoperative type C spondylolisthesis was found to predict increased LL (β-coefficient = 4.46, P = 0.0054) and decreased PI-LL (β-coefficient = -3.49, P = 0.025) at 1 year compared with type A spondylolisthesis.

CONCLUSIONS

Clinical and radiographic outcomes differed significantly by preoperative CARDS classification type for patients undergoing posterior decompression and fusion for L4-L5 DS.

LEVEL OF EVIDENCE

Level III.

Patients With Preoperative Cervical Deformity Experience Similar Clinical Outcomes to Those Without Deformity Following 1-3 Level Anterior Cervical Decompression and Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim was to compare the outcomes of patients with incompletely corrected cervical deformity against those without deformity following short-segment anterior cervical decompression and fusion for clinically significant radiculopathy or myelopathy.

SUMMARY OF BACKGROUND DATA

Cervical deformity has increasingly been recognized as a driver of disability and has been linked to worse patient-reported outcomes measures (PROMs) after surgery.

METHODS

Patients 18 years or above who underwent 1-3 level anterior cervical decompression and fusion to address radiculopathy and/or myelopathy at a single institution between 2014 and 2018 with at least 1 year of PROMs were reviewed. Patients were categorized based on cervical deformity into 2 groups: sagittal vertebral axis (cSVA) ≥40 mm as the deformity group, and cSVA <40 mm as the nondeformity group. Patient demographics, surgical parameters, preoperative and postoperative radiographs, and minimum 1-year PROMs were compared.

RESULTS

Of the 230 patients, 191 (83%) were in the nondeformity group and 39 (17%) in the deformity group. Patients with deformity were more likely to be male (69.2% vs. 40.3%, P<0.001) and have a greater body mass index (32.8 vs. 29.7, P=0.028). The deformity group had significantly greater postoperative cSVA (44.2 vs. 25.1 mm, P<0.001) but also had significantly greater ∆cSVA (-4.87 vs. 0.25 mm, P=0.007) than the nondeformity group. Both groups had significant improvements in visual analog scale arm, visual analog scale neck, Short-Form 12 Physical Component Score, and neck disability index (NDI) (P<0.001). However, the deformity group experienced significantly greater ∆NDI and ∆mental component score (MCS)-12 scores (-19.45 vs. -11.11, P=0.027 and 7.68 vs. 1.32, P=0.009).

CONCLUSIONS

Patients with preoperative cervical sagittal deformity experienced relatively greater improvements in NDI and MCS-12 scores than those without preoperative deformity. These results suggest that complete correction of sagittal alignment is not required for patients to achieve significant clinical improvement.

LEVEL OF EVIDENCE

III.

Is There Clinical Improvement Associated With Intradiscal Therapies? A Comparison Across Randomized Controlled Studies

STUDY DESIGN

Post hoc comparison using single-site data from 4 multicenter randomized controlled trials.

OBJECTIVES

Discogenic back pain is associated with significant morbidity and medical cost. Several terminated, unreported randomized controlled trials have studied the effect of intradiscal biologic injections. Here we report single-center outcomes from these trials to determine if there is clinical improvement associated with these intradiscal injections.

METHODS

Post hoc comparison was performed using single-site data from 4 similar multi-center randomized controlled trials. All trials evaluated an injectable therapy (growth factor, fibrin sealant, or stem cells) for symptomatic lumbar disc disease with near-identical inclusion and exclusion criteria. Demographics and patient reported outcomes were analyzed across treatment arms postinjection.

RESULTS

A total of 38 patients were treated with biologic agents and 12 were treated with control saline injections. There was a significant decrease in visual analogue score (VAS) pain for both the investigational and saline groups up to 12 months postinjection (P < .01). There was no significant difference in VAS scores between the saline and investigational groups at 12 months. Similarly, there was significant improvement in patient-reported disability scores in both the investigational and saline groups at all time points. There were no significant differences in disability score improvement between the saline and investigational treatment groups at 12 months postinjection.

CONCLUSIONS

A single-center analysis of 4 randomized controlled studies demonstrated no difference in outcomes between therapeutic intradiscal agents (growth factor, fibrin sealant, or stem cells) and control saline groups. In all groups, patient reported pain and disability scores decreased significantly. Future studies are needed to evaluate the therapeutic benefit of any intradiscal injections.

The Effect of Anterior Cervical Discectomy and Fusion Procedure Duration on Patient-Reported Outcome Measures

OBJECTIVE

To determine whether operative duration of anterior cervical discectomy and fusion (ACDF) significantly affects patient-reported outcome measures (PROMs) 90 days after surgery and at 1-year follow-up.

METHODS

Patients who underwent primary 1-level to 4-level ACDF were retrospectively identified. Demographic data and PROMs were collected through chart review. Patients were split into short, medium, and long tertiles based on procedure duration. PROM surveys were administered preoperatively as baseline measurements, at initial follow-up (between 60 and 120 days postoperatively), and at 1 year postoperatively. Outcomes included Neck Disability Index, Short-Form 12 Physical Component Score (PCS-12), Short-Form 12 Mental Component Score, visual analog scale (VAS) neck score, and VAS arm score.

RESULTS

Significant short-term improvements were found across all groups for all PROMs. All groups showed long-term improvements in Short-Form 12 Mental Component Score, PCS-12, Neck Disability Index, VAS neck score, and VAS arm score, with the exception of the medium-duration group in PCS-12 (P = 0.093). On multivariate analysis, short-duration procedures predicted better improvement in VAS neck score (β = -1.01; P = 0.012) and VAS arm score (β = -1.38; P = 0.002) compared with long-duration procedures, whereas medium-duration procedures resulted in better improvement in VAS arm score (β = -1.00; P = 0.011). Further, short and medium duration was a predictor of decreased length of hospital stay (β = -0.67, P = 0.001 and β = -0.59, P = 0.001, respectively) compared with long-duration procedures.

CONCLUSIONS

All groups improved after ACDF regardless of surgical duration. Further, surgical duration was not a predictor of differing improvement in physical function or disability.

Severe Chin-on-Chest Cervical Spine Deformity in the Setting of Stiff-Person Syndrome: A Case Report

CASE

Stiff-person syndrome (SPS) presents with progressive muscle rigidity, postural instability, and periodic debilitating spasms. Reports of axial hyperextension exist, but kyphotic deformities have not been described. We surgically treated a patient with debilitating SPS and severe cervicothoracic hyperkyphosis with posterior spinal fusion and instrumentation. At 1-year follow-up, the patient displayed better upright gait and forward gaze, 18° cervical lordosis, and improved patient-reported outcome scores.

CONCLUSION

SPS can lead to extreme spinal deformity and disease, including hyperkyphosis of the cervicothoracic spine, and can successfully be managed with a multidisciplinary team and a posterior-only correction with spinal instrumentation and fusion.

Electrospun, synthetic bone void filler promotes human MSC function and BMP-2 mediated spinal fusion

INTRODUCTION

Synthetic bone grafts are often used to achieve a well-consolidated fusion mass in spinal fusion procedures. These bone grafts function as scaffolds, and ideally support cell function and facilitate protein binding.

OBJECTIVE

The aim was to characterize an electrospun, synthetic bone void filler (Reb) for its bone morphogenetic protein (BMP)-2 release properties and support of human mesenchymal stem cell (hMSC) function in vitro, and its efficacy in promoting BMP-2-/bone marrow aspirate-(BMA)-mediated posterolateral spinal fusion (PLF) in vivo.

METHODS

BMP-2 release kinetics from Reb versus standard absorbable collagen sponge (ACS) was determined. hMSC adhesion and proliferation on Reb was tested using cell counting, fluorescence microscopy and MTS. Cell osteogenic differentiation was quantified via cellular alkaline phosphatase (ALP) activity. For in vivo analysis, 18 Lewis rats were treated during PLF surgery with the following groups: (I) Reb + BMA, (II) Reb + BMA + BMP-2 and (III) BMA. A safe, minimally effective dose of BMP-2 was used. Fusion consolidation was followed for 3 months using radiography and micro-CT. After sacrifice, fusion rate and biomechanical stiffness was determined using manual palpation, biomechanical tests and histology.

RESULTS

In vitro, BMP-2 release kinetics were similar between Reb versus ACS. MSC proliferation and differentiation were increased in the presence of Reb. At 3 months post-surgery, fusion rates were 29% (group I), 100% (group II), and 0% (group III). Biomechanical stiffness was higher in group II versus I. Micro-CT showed an increased bone volume and connectivity density in group II. Trabecular thickness was increased in group I versus II. H&E staining showed newly formed bone in group II only.

CONCLUSIONS

Reb possesses a high protein binding affinity and promotes hMSC function. Combination with BMA and minimal dose BMP-2 allowed for 100% bone fusion in vivo. This data suggests that a minimally effective dose of BMP-2 can be used when combined with Reb.

Optimization of a rat lumbar IVD degeneration model for low back pain

INTRODUCTION

Intervertebral disc (IVD) degeneration is often associated with low back pain and radiating leg pain. The purpose of this study is to develop a reproducible and standardized preclinical model of painful lumbar IVD degeneration by evaluation of structural and behavioral changes in response to IVD injury with increasing needle sizes. This model can be used to develop new therapies for IVD degeneration.

METHODS

Forty-five female Sprague Dawley rats underwent anterior lumbar disc needle puncture at levels L4-5 and L5-6 under fluoroscopic guidance. Animals were randomly assigned to four different experimental groups: needle sizes of 18 Gauge (G), 21G, 23G, and sham control. To monitor the progression of IVD degeneration and pain, the following methods were employed: μMRI, qRT-PCR, histology, and biobehavioral analysis.

RESULTS

T1- and T2-weighted μMRI analysis showed a correlation between the degree of IVD degeneration and needle diameter, with the most severe degeneration in the 18G group. mRNA expression of markers for IVD degeneration markers were dysregulated in the 18G and 21G groups, while pro-nociceptive markers were increased in the 18G group only. Hematoxylin and Eosin (H&E) and Alcian Blue/Picrosirius Red staining confirmed the most pronounced IVD degeneration in the 18G group. Randall-Selitto and von Frey tests showed increased hindpaw sensitivity in the 18G group.

CONCLUSION

Our findings demonstrate that anterior disc injury with an 18G needle creates severe IVD degeneration and mechanical hypersensitivity, while the 21G needle results in moderate degeneration with no increased pain sensitivity. Therefore, needle sizes should be selected depending on the desired phenotype for the pre-clinical model.

Intervertebral Disc Repair: Current Concepts

STUDY DESIGN

Review article.

OBJECTIVE

A review of the literature on current strategies utilized in intervertebral regeneration and repair efforts.

METHODS

A review of the literature and analysis of the data to provide an updated review on current concepts of intervertebral disc repair and regeneration efforts.

RESULTS

Multiple regenerative strategies for intervertebral disc regeneration are being employed to reduce pain and improve quality of life. Current promising strategies include molecular therapy, gene therapy, cell-based therapy, and augmentation with biomaterials. Multiple clinical trials studying biologic, cell-based, and scaffold-based injectable therapies are currently being investigated.

CONCLUSION

Low back pain due to intervertebral disc disease represents a significant health and societal burden. Current promising strategies include molecular therapy, gene therapy, cell-based therapy, and augmentation with biomaterials. To date, there are no Food and Drug Administration-approved intradiscal therapies for discogenic back pain, and there are no large randomized trials that have shown clinically significant improvement with any investigational regenerative treatment. Multiple clinical trials studying biologic, cell-based, or scaffold-based injectable therapies are being currently investigated.

Nationwide Analysis of Femoral Neck Fractures in Elderly Patients: A Receding Tide

BACKGROUND

Geriatric femoral neck fractures are associated with substantial morbidity and medical cost. We evaluated the incidence and management trends of femoral neck fractures in recent years in the U.S.

METHODS

Patient data from 2003 through 2013 were obtained from the Nationwide Inpatient Sample database. Femoral neck fractures in patients ≥65 years old were identified and grouped using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure codes for internal fixation, hemiarthroplasty, or total hip arthroplasty (THA). The nationwide incidence of femoral neck fractures was calculated and presented as an age-adjusted population rate. Univariable methods were used for trend analysis and comparisons between groups. Logistic regression modeling was used to analyze complications.

RESULTS

From 2003 to 2013, we identified 808,940 femoral neck fractures in patients ≥65 years old. The national age-adjusted incidence of femoral neck fractures decreased from 242 per 100,000 U.S. adults in 2003 to 146 in 2013. The proportion of fractures managed operatively with THA increased over time (5.9% in 2003 versus 7.4% in 2013; p < 0.001). Concurrently, the use of hemiarthroplasty declined (65.1% versus 63.6%; p < 0.001). In 2013, the median age of the patients treated with THA was significantly younger (77.3 years) compared with that in the hemiarthroplasty and internal fixation groups (83.2 and 82.0 years). The THA group had significantly higher median initial hospital costs ($17,097) compared with the hemiarthroplasty and internal fixation groups ($14,776 and $10,462).

CONCLUSIONS

In the last decade, the total number and population rate of femoral neck fractures in the elderly declined significantly. There was a modest but significant increase in the utilization of THA.

CLINICAL RELEVANCE

This report identifies the changing trends in clinical practice in the treatment of geriatric femoral neck fractures in the U.S. Treating physicians should be aware of these trends, which include a decreasing national incidence of geriatric femoral neck fractures as well as an increase in the use of THA.

Diagnosis and surgical management of breast cancer metastatic to the spine

Breast cancer is the most common malignancy and the second leading cause of death in Western women. Breast cancer most commonly metastasizes to the bone and has a particular affinity with the spine, accounting for 2/3 of osseous metastases discovered. With significant improvements in cancer therapies, the number of patients at risk for symptomatic spinal metastases is likely to increase. Patients may suffer from intractable pain and neurological dysfunction, negatively influencing their quality of life. Timely diagnosis of patients is crucial and has been aided by several breakthrough advances in imaging techniques which aid in detection, staging, and follow-up of bone metastases. Breast metastases are usually responsive to hormonal therapy and pharmacologic interventions, but skeletal metastases often require surgical intervention. The treatments are palliative but goals include the preserving or restoring neurologic function, ensuring spinal stability, and relieving pain. Advances in surgical techniques and instrumentation have allowed more effective decompression and stabilization of the spine, and with the support of recent evidence the trend has shifted towards using more advanced surgical options in appropriately selected patients. In this review, the clinical presentation, diagnosis, patient selection, and surgical management of breast cancer metastatic to the spine are discussed.

Prolonged survival following aggressive treatment for metastatic breast cancer in the spine

In 2007, members of our group reported a 21 month median survival for patients undergoing surgery for metastatic breast cancer in the spinal column. Cervical spine metastases were associated with decreased survival, Estrogen receptor positivity was associated with improved survival, and age and visceral metastases did not significantly impact survival. In the current study, we reassess these variables in the context of modern adjuvant therapies, and investigate the impact of the Spinal Instability Neoplastic Score (SINS). We report an observational cohort of 43 patients undergoing surgical resection for metastatic breast cancer of the spine treated at a single academic institution from June 2002 to August 2011. Patient medical records were reviewed in accordance with policies outlined by the University Institutional Review Board. Median overall survival following surgery for metastatic breast cancer in the spine was 26.8 months. 1 year overall survival was 66%. 5 year-overall survival was 4%. Age (p=0.12), preoperative functional status (p=0.17), location of metastasis (p=0.34), the presence of visceral metastases (p=0.68), and spinal instability (p=0.81) were not significant variables on survival analysis. Postoperative adjuvant therapy with a single modality (radiation or chemotherapy) was associated with a significantly lower median survival compared to dual therapy with chemotherapy and radiation (p=0.042). Patients that received radiation and chemotherapy after surgery were younger but demonstrated prolonged median survival versus single modality therapy. This data supports the concept that visceral metastases do not impact survival, however cervical spine lesions were not associated with decreased survival.

Factors Associated With Improved Outcomes Following Decompressive Surgery for Prostate Cancer Metastatic to the Spine

BACKGROUND:

Metastatic spinal cord compression from prostate cancer is a debilitating disease causing neurological deficits, mechanical instability, and intractable pain. Surgical management may improve quality of life.

OBJECTIVE:

To define postoperative outcomes and explore associations with prolonged survival for patients with metastatic prostate cancer.

METHODS:

Retrospective chart reviews were performed of all patients undergoing spinal surgery for metastatic cancer from June 1, 2002 to August 31, 2011. Patient demographics, surgical details, adjuvant therapies, outcomes, complications, and postoperative survival were reviewed.

RESULTS:

Twenty-seven patients with prostate cancer underwent surgery at a median age of 65 years (range, 46-82 years). After surgery, 93% of patients had preserved or improved neurological status, 56% of nonambulatory patients recovered ambulation, 43% of incontinent patients recovered continence, and 23% experienced complications. Postoperative Frankel grades were significantly improved by at least 1 letter grade at 1 month (P = .03). The median analgesic and steroid usage was significantly lower up to 3 months and 6 months postoperatively, respectively (P = .007, .005). Median survival following surgery was 10.2 months, and patients with castration-resistant prostate cancer had a shorter median survival than those with hormone-naïve disease (9.8 vs 40 months). Better preoperative performance status was an independent predictor of survival (P = .02). Younger age (P = .005) and instrumentation greater than 7 spinal levels (P = .03) were associated with complications.

CONCLUSION:

Spinal surgery for prostate metastases improves neurological function and decreases analgesic requirements. Our findings support surgical intervention for carefully selected patients, and knowledge of preoperative hormone sensitivity and performance status may help with risk stratification.

The spectrum of complications following left ventricular assist device placement

INTRODUCTION

Left ventricular assist device (LVAD) support is associated with many complications, but relatively few studies have examined the full spectrum of complications beyond infectious and bleeding events.

METHODS

We conducted a retrospective review of patients receiving either a pulsatile-flow Heartmate XVE (HM1; Thoratec Corp., Pleasanton, CA, USA) or continuous-flow Heartmate II (HM2; Thoratec Corp.) LVAD at our institution (June 2000 to March 2012). Frequency and date of onset of nonbleeding, noninfectious complications were examined.

RESULTS

One hundred eighty-two LVADs were implanted, 49 HM1, and 133 HM2. Support duration was longer for HM2s (median 358 vs. 112 days; p = 0.0003). Overall, the most frequent complications were respiratory failure, ventricular arrhythmia, atrial arrhythmia, right heart failure, and renal failure. Respiratory failure, arrhythmias, severe psychiatric events, and renal failure all occurred with median date of onset ≤ seven days postprocedure. Right heart failure, hepatic failure, thromboembolism, and transient ischemic attacks had a median date of onset 8 to 30 days postprocedure. Stroke, hemolysis, and device failure occurred mostly more than a month postoperatively. Right heart failure, hepatic failure, and device failure were more frequent in HM1 patients than in HM2 patients. Several events, including stroke, had much later onset in HM2 patients.

CONCLUSION

In this 10-year review of complications following LVAD implantation, the most common adverse events tended to occur early after implantation. As pulsatile-flow HM1s showed greater frequency and earlier onset of some adverse events, our data suggest better overall outcomes with the continuous-flow HM2s.