The Incidence of Double Crush Syndrome in Surgically Treated Patients

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

Cervical radiculopathy and peripheral entrapment neuropathies often have overlapping symptoms that are difficult to distinguish on physical examination. Small-scale studies have attempted to report the incidence of this phenomenon, often called double crush syndrome (DCS), with varying results. The present study aims to determine the incidence of concomitant cervical radiculopathy and peripheral nerve compression and to determine if the DCS hypothesis, which states that compression of a nerve at one site leaves it more susceptible to compression at another, is valid.

METHODS

The PearlDiver database was queried from 2010 to 2020. The incidence of peripheral neuropathy in cervical radiculopathy was assessed. Propensity score matching was used to determine if patients with cervical radiculopathy were more likely to have peripheral nerve compression compared to controls, and vice versa, to test the DCS hypothesis.

RESULTS

The database contains records of 90,772 632 patients. The incidence of carpal tunnel syndrome (CTS) or peripheral ulnar nerve compression (PUnC) in cervical radiculopathy was 9.98% and 3.15%, respectively. The incidence of both carpal tunnel syndrome and PUnC in cervical radiculopathy was 1.84%. Patients with cervical radiculopathy were more likely than matched controls to have both CTS (P < .001) and PUnC (P < .001). Patients with CTS (P < .001) and with PUnC (P < .001) were more likely to have cervical radiculopathy than the control cohort.

CONCLUSIONS

The incidence of DCS is reported. Patients with cervical radiculopathy are more likely than matched controls to have peripheral nerve compression, and vice versa, in support of the DCS hypothesis.

Top 25 Most Cited Articles on Intraoperative Computer Tomography-Guided Navigation in Spine Surgery

BACKGROUND

In recent years, the use of intraoperative computer tomography-guided (CT-guided) navigation has gained significant popularity among health care providers who perform minimally invasive spine surgery. This review aims to identify and analyze trends in the literature related to the widespread adoption of CT-guided navigation in spine surgery, emphasizing the shift from conventional fluoroscopy-based techniques to CT-guided navigation.

METHODS

Articles pertaining to this study were identified via a database review and were hierarchically organized based on the number of citations. An "advanced document search" was performed on September 28th, 2022, utilizing Boolean search operator terms. The 25 most referenced articles were combined into a primary list after sorting results in descending order based on the total number of citations.

RESULTS

The "Top 25" list for intraoperative CT-guided navigation in spine surgery cumulatively received a total of 2742 citations, with an average of 12 new citations annually. The number of citations ranged from 246 for the most cited article to 60 for the 25th most cited article. The most cited article was a paper by Siewerdsen et al., with 246 total citations, averaging 15 new citations per year.

CONCLUSIONS

Intraoperative CT-guided navigation is 1 of many technological advances that is used to increase surgical accuracy, and it has become an increasingly popular alternative to conventional fluoroscopy-based techniques. Given the increasing adoption of intraoperative CT-guided navigation in spine surgery, this review provides impactful evidence for its utility in spine surgery.

Top 25 Most-Cited Articles on Robotic-Assisted Lumbar Spine Surgery

BACKGROUND

Robot-guided lumbar spine surgery has evolved rapidly with evidence to support its utility and feasibility compared with conventional freehand and fluoroscopy-based techniques. The objective of this study was to assess trends among the top 25 most-cited articles pertaining to robotic-guided lumbar spine surgery.

METHODS

An "advanced document search" using Boolean search operator terms was performed on 16 November 2022 through the Web of Science and SCOPUS citation databases to determine the top 25 most-referenced articles on robotic lumbar spine surgery. The articles were compiled into a directory and hierarchically organized based on the total number of citations.

RESULTS

Cumulatively, the "Top 25" list for robot-assisted navigation in lumbar spine surgery received 2240 citations, averaging 97.39 citations annually. The number of citations ranged from 221 to 40 for the 25 most-cited articles. The most-cited study, by Kantelhardt et al, received 221 citations, averaging 18 citations per year.

CONCLUSIONS

As utilization of robot-guided modalities in lumbar spine surgery increases, this review highlights the most impactful studies to support its efficacy and implementation. Practical considerations such as cost-effectiveness, however, need to be better defined through further longitudinal studies that evaluate patient-reported outcomes and cost-utility.

CLINICAL RELEVANCE

Through an overview of the top 25 most-cited articles, the present review highlights the rising prominence and technical efficacy of robotic-guided systems within lumbar spine surgery, with consideration to pragmatic limitations and need for additional data to facilitate cost-effective applications.

LEVEL OF EVIDENCE: 5

Cervical Disc Arthroplasty: Rationale, Designs, and Results of Randomized Controlled Trials

BACKGROUND

This review outlines clinical data and characteristics of current Food and Drug Administration (FDA)-approved implants in cervical disc replacement/cervical disc arthroplasty (CDR/CDA) to provide a centralized resource for spine surgeons.

METHODS

Randomized controlled trials (RCTs) on CDR/CDA were identified using a search of the PubMed, Web of Science, and Google Scholar databases. The initial search identified 69 studies. Duplicates were removed, and the following inclusion criteria were applied when determining eligibility of RCTs for the current review: (1) discussing CDR/CDA prosthesis and (2) published within between 2010 and 2020. Studies without clinical data or that were not RCTs were excluded. All articles were reviewed independently by 2 authors, with the involvement of an arbitrator to facilitate consensus on any discrepancies.

RESULTS

A total of 34 studies were included in the final review. Findings were synthesized into a comprehensive table describing key features and clinical results for each FDA-approved CDR/CDA implant and are overall suggestive of expanding indications and increasing utilization.

CONCLUSIONS

RCTs have provided substantial evidence to support CDR/CDA for treating single- and 2-level cervical degenerative disc disease in place of conventional anterior cervical discectomy and fusion.

CLINICAL RELEVANCE

This review provides a resource that consolidates relevant clinical data for current FDA-approved implants to help spine surgeons make an informed decision during preoperative planning.

LEVEL OF EVIDENCE: 5

Systematic Review and Meta-Analysis of the Effect of Osteoporosis on Fusion Rates and Complications Following Surgery for Degenerative Cervical Spine Pathology

BACKGROUND

As the elderly population grows, the increasing prevalence of osteoporosis presents a unique challenge for surgeons. Decreased bone strength and quality are associated with hardware failure and impaired bone healing, which may increase the rate of revision surgery and the development of complications. The purpose of this review is to determine the impact of osteoporosis on postoperative outcomes for patients with cervical degenerative disease or deformity.

METHODS

A systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Medical Subject Headings terms involving spine surgery for cervical degenerative disease and osteoporosis were performed. This review focused on radiographic outcomes, as well as surgical and medical complications.

RESULTS

There were 16 studies included in the degenerative group and 9 in the deformity group. Across degenerative studies, lower bone mineral density was associated with increased rates of cage subsidence in osteoporotic patients undergoing operative treatment for cervical degenerative disease. Most studies reported varied results on the relationship between osteoporosis and other outcomes such as revision and readmission rates, costs, and perioperative complications. Our meta-analysis suggests that osteoporotic patients carry a greater risk of reduced fusion rates at 6 months and 1 year postoperatively. With respect to cervical deformity correction, although individual complication rates were unchanged with osteoporosis, the collective risk of incurring any complication may be increased in patients with poor bone stock.

CONCLUSIONS

Overall, the literature suggests that outcomes for osteoporotic patients after cervical spine surgery are multifactorial. Osteoporosis seems to be a significant risk factor for developing cage subsidence and pseudarthrosis postoperatively, whereas reports on medical and hospital-related metrics were inconclusive. Our findings highlight the challenges of caring for osteoporotic patients and underline the need for adequately powered studies to understand how osteoporosis changes the risk index of patients undergoing cervical spine surgery.

CLINICAL RELEVANCE

In patients undergoing cervical spine surgery for degenerative disease, osteoporosis is a significant risk factor for long-term postoperative complications-notably cage subsidence and pseudarthrosis. Given the elective nature of these procedures, interdisciplinary collaboration between providers should be routinely implemented to enable medical optimization of patients prior to cervical spine surgery.

LEVEL OF EVIDENCE: 1

The Incidence of Vertebral Artery Injury in Cervical Spine Surgery

BACKGROUND

Previously reported estimates of vertebral artery injuries (VAIs) during cervical spine surgery relied on self-reported survey studies and retrospective cohorts, which may not be reflective of national averages. The largest study to date reports an incidence of 0.07%; however, significant variation exists between different cervical spine procedures. This study aimed to identify the incidence of VAIs in patients undergoing cervical spine procedures for degenerative pathologies.

METHODS

In this retrospective cohort study, a national insurance database was used to access data from the period 2010-2020 of patients who underwent anterior cervical discectomy and fusion, anterior corpectomy, posterior cervical fusion (C3-C7), or C1-C2 posterior fusion for degenerative pathologies. Patients who experienced a VAI were identified, and frequencies for the different procedures were compared.

RESULTS

This study included 224,326 patients, and overall incidence of VAIs across all procedures was 0.03%. The highest incidence of VAIs was estimated in C1-C2 posterior fusion (0.12%-1.10%). The number of patients with VAIs after anterior corpectomy, anterior cervical discectomy and fusion, and posterior fusion was 14 (0.06%), 43 (0.02%), and 26 (0.01%), respectively.

CONCLUSIONS

This is the largest study to date to our knowledge that provides frequencies of VAIs in patients undergoing cervical spine surgery in the United States. The overall incidence of 0.03% is lower than previously reported estimates, but significant variability exists between procedures, which is an important consideration when counseling patients about risks of surgery.

Preoperative Epidural Steroid Injection Does Not Increase Infection Risk Following Posterior Cervical Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The purpose of this study was to characterize the infection risk of preoperative epidural steroid injection (ESI) in patients undergoing posterior cervical surgery.

SUMMARY OF BACKGROUND DATA

ESI is a helpful tool for alleviating pain and is often used as a diagnostic tool before cervical surgery. However, a recent small-scale study found that ESI before cervical fusion was associated with an increased risk of postoperative infection.

MATERIALS AND METHODS

Patients from 2010 to 2020 with cervical myelopathy, spondylosis, and radiculopathy who underwent posterior cervical procedure including laminectomy, laminoforaminotomy, fusion, or laminoplasty were queried from the PearlDiver database. Patients who underwent revision or fusion above C2 or who had a diagnosis of neoplasm, trauma, or preexisting infection were excluded. Patients were divided on whether they received an ESI within 30 days before the procedure and subsequently matched by age, sex, and preoperative comorbidities. The χ 2 analysis was used to calculate the risk of postoperative infection within 90 days. Logistic regression controlling for age, sex, Elixhauser Comorbidity Index, and operated levels was conducted within the unmatched population to assess infection risk for injected patients across procedure subgroups.

RESULTS

Overall, 299,417 patients were identified with 3897 having received a preoperative ESI and 295,520 who did not. Matching resulted in 975 in the injected group and 1929 in the control group. There was no significant difference in postoperative infection rate in those who received an ESI within 30 days preoperatively and those who did not (3.28% vs. 3.78%, odds ratio=0.86, 95% CI: 0.57-1.32, P =0.494). Logistic regression accounting for age, sex, Elixhauser Comorbidity Index, and levels operated demonstrated that injection did not significantly increase infection risk in any of the procedure subgroups.

CONCLUSIONS

The present study found no association between preoperative ESI within 30 days before surgery and postoperative infection in patients undergoing posterior cervical surgery.

Increased dislocation rates following total hip arthroplasty in patients with ankylosing spondylitis

BACKGROUND

Patients with ankylosing spondylitis (AS) experience abnormal spinopelvic motion due to chronic inflammation of the axial skeleton, predisposing them to impingement and dislocation. The purpose of this study was to evaluate total hip arthroplasty (THA) dislocation rates in AS patients and evaluate the effects of age and gender on dislocation risk.

METHODS

Patients who underwent primary THA from 2005 to 2014 were identified using the PearlDiver database. AS patients were compared to age- and gender-matched controls without AS. Patients with a history of spine pathology or spine surgery were excluded. Univariate analyses were performed based on age and sex to evaluate dislocation rates at 90 days, 6 months, 1 year, and 5 years postoperatively.

RESULTS

A total of 2792 THA patients (59.6% male) with AS were identified and compared to an age- and gender-matched control group of 5582 THA patients (59.5% male) without AS or known spine pathology. At final follow-up, there were 96 dislocations (3.4%) in the AS group and 138 (2.5%) dislocations in the control group (OR 1.40; 95% CI, 1.08-1.83; p = 0.0118). AS patients ⩾70 years old had higher dislocation rates at all time points (OR range, 1.75-2.09; p < 0.05) compared to controls. At 5-year follow-up, dislocation-free survivorship was 95.7% (95% CI, 94.5-96.9%) for AS patients ⩾70 years old compared to 97.3% (95% CI, 96.6-98.0%) for patients ⩾70 years old without AS.

CONCLUSIONS

Older AS patients have higher dislocation rates following THA. This effect is likely related to decreased spinopelvic motion in the sagittal plane, predisposing patients to impinge and dislocate.

A Decreasing National Trend in Lumbar Disc Arthroplasty

STUDY DESIGN

Retrospective National Database Study.

OBJECTIVES

The aim of this study was to investigate the national trend of lumbar disc arthroplasty (LDA) utilization from 2005 to 2017.

METHODS

Patients undergoing primary LDA between 2005 and 2017 were identified in the National Inpatient Sample (NIS) database. Year of the procedure, demographic, socioeconomic, hospital, and cost parameters were analyzed. The data was weighted using provided weights from the NIS database to generate national estimates of LDA procedure incidence. Lastly, we assessed the incidence of cervical disc arthroplasty (CDA) between 2005 and 2017 to serve as a historical comparison.

RESULTS

An estimated 20 460 patients underwent primary LDA in the United States between 2005 and 2017. There was an initial decrease in LDA procedures between 2005 and 2006 and then a plateau between 2006 and 2009. From 2010 to 2013, there was a significant year-over-year decrease in annual LDA procedures performed, followed by a second plateau from 2014 to 2017. Overall, LDA procedures decreased 82% from 2005 to 2017. Over the same time, the annual incidence of CDA utilization increased 795% from approximately 474 procedures in 2005 to 4245 procedures in 2017 (P < .01).

CONCLUSIONS

Lumbar disc arthroplasty utilization decreased 82% from 2005 to 2017, with a significant decrease in the rate of utilization noted after 2010. The utilization of LDA to treat selected degenerative lumbar conditions has not paralleled the increasing popularity of CDA, and, in fact, has demonstrated a nearly opposite utilization trend.

The Role of Sex Hormones in Degenerative Disc Disease

STUDY DESIGN

Narrative review.

OBJECTIVES

The purpose of this review is to outline the role of sex hormones, particularly estrogen, in the pathogenesis of degenerative disc disease (DDD).

METHODS

A narrative review of studies discussing sex hormones and intervertebral disc (IVD) degeneration was conducted through a search of bibliographic databases to identify various mechanisms involved in effectuating DDD.

RESULTS

Estrogen-deficient states negatively impact various aspects of IVD function. These internal hormone environments reflect routine changes that commonly arise with physiologic aging and can compromise IVD structural integrity through a host of processes. Additionally, allosteric molecules such as micro-RNAs (mi-RNAs) and G protein-coupled estrogen receptors (GPER) antagonists can bind to estrogen receptors and inhibit protective downstream effects with estrogen receptor signaling. Furthermore, cursory studies have observed chondrogenic effects with testosterone supplementation, although the specific mechanism remains unclear.

CONCLUSIONS

Regulation of sex hormones, namely estrogen and testosterone, significantly impacts the structural integrity and function of IVDs. Uncovering underlying interactions driving these regulatory processes can facilitate development of novel, clinical therapies to treat DDD.

Nationwide Analysis of Sacroiliac Joint Fusion Trends: Regional Variations in Utilization and Population Characteristics

STUDY DESIGN/SETTING

Retrospective cohort analysis.

OBJECTIVES

This study evaluates utilization and demographic trends for sacroiliac joint (SIJ) fusions across the United States (US).

METHODS

Patients who underwent SIJ fusion from 2010-2021 were identified within the PearlDiver national database using International Classification of Disease (ICD-9, ICD-10) and Current Procedural Terminology (CPT) codes. Indications for trauma, malignancy, or infection were excluded. Demographic, clinical, and procedure characteristics were recorded along with annual utilization rates. Annual percent change (APC) was calculated to identify increasing or decreasing utilization from prior years. Negative binomial regression was performed to project subsequent utilization for 2022-2028. Chi-squared analysis followed by post-hoc comparisons were used to compare differences in diagnostic indications and clinical features associated with SIJ fusion across regions. Bonferroni adjustments were applied to P-values for pairwise analyses.

RESULTS

Overall, 18 032 patients (69.8% female, mean age = 51.0 + 13.4 years) underwent SIJ fusion between 2010 and 2021. Annual utilization increased by 33.5% on average. The South comprised the largest proportion of cases (48.9%). Projections for 2022-2028 predict continued growth in procedures, with an overall increase of 1100% from 1350 cases in 2021 to 16 195 by end of 2028. Spondyloarthropathy-induced sacroilitis was the most prevalent diagnostic indication nationwide (51%). Of patients undergoing SIJ fusion, 18% had a prior lumbar fusion, and only 45% received a preoperative diagnostic SIJ injection.

CONCLUSION

As SIJ fusion is increasingly utilized to treat refractory SIJ-based pain, establishing evidence-based guidelines, improving diagnostic strategies, and defining indications are imperative to support growing applications within clinical practice.

Evaluating Changes to the Modified K-Line Using Kinematic MRIs

STUDY DESIGN

Retrospective cross-sectional review of a large database.

OBJECTIVE

Little is known regarding extension K-lines for treatment of cervical myelopathy. Therefore, this study seeks to examine differences between K-lines drawn in neutral and extension.

SUMMARY OF BACKGROUND DATA

The modified K-line is a radiological tool used in surgical planning of the cervical spine. As posterior cervical decompression and fusion often results in patients being fused in a more lordotic position than the preoperative neutral radiograph, a K-line measured in the extension position may offer better utility for these patients.

MATERIALS AND METHODS

Total of 97 patients were selected with T2-weighted, upright cervical magnetic resonance imaging taken in neutral and extension. For each patient, the K-line was drawn at the mid-sagittal position for both neutral and extension. The distance from the most posterior portion of each disk (between C2 and C7) to the K-line was measured in neutral and extension and the difference was calculated. Paired t test was used to assess significant differences.

RESULTS

Across all levels between C2 and C7 there was an increase in the distance between the dorsal aspect of the disk and K-line when comparing neutral and extension radiographs. The average change in difference (extension minus neutral) at each cervical spinal level was 0.9 mm (C2-C3), 2.5 mm (C3-C4), 2.6 mm (C4-C5), 2.0 mm (C5-C6), and 0.9 mm (C6-C7). A paired t test showed that the K-line increase from neutral to extension was statistically significant across all disk levels ( P <0.001).

CONCLUSION

When positioned in extension, patients experience a significant increase in distance from the dorsal aspect of a disk to the K-line compared to when positioned in neutral, especially between C3 and C6. This is clinically relevant for surgeons considering a posterior cervical decompression and fusion in patients with a negative modified K-line on preoperative magnetic resonance imaging, as these patients may have enough cervical cord drift back when fused in an extended position, maximizing likelihood of improving postoperative DSM functional outcomes.

Complication Rates and Utilization Trends of 3-Level Posterior Column Osteotomy Compared to Single-Level Pedicle Subtraction Osteotomy

OBJECTIVE

The objective of this study is to assess differences in complication profiles between 3-level posterior column osteotomy (PCO) and single-level pedicle subtraction osteotomy (PSO) as both are reported to provide similar degrees of sagittal correction.

METHODS

The PearlDiver database was queried retrospectively using International Classification of Disease, 9th and 10th edition and Current Procedural Terminology codes to identify patients who underwent PCO or PSO for degenerative spine disease. Patients under age 18 or with history of spinal malignancy, infection, or trauma were excluded. Patients were separated into 2 cohorts, 3-level PCO or single-level PSO, matched at a 1:1 ratio based on age, sex, Elixhauser comorbidity index, and number of fused posterior segments. Thirtyday systemic and procedure-related complications were compared.

RESULTS

Matching resulted in 631 patients for each cohort. PCO patients had decreased odds of respiratory (odds ratio [OR], 0.58; 95% confidence interval [CI], 0.43-0.82; p = 0.001) and renal complications (OR, 0.59; 95% CI, 0.40-0.88; p = 0.009) compared to PSO patients. There was no significant difference in cardiac complications, sepsis, pressure ulcer, dural tear, delirium, neurologic injuries, postoperative hematoma, postoperative anemia, or overall complications.

CONCLUSION

Patients who undergo 3-level PCO have decreased respiratory and renal complications compared to single-level PSO. No differences were found in the other complications studied. Considering both procedures achieve similar sagittal correction, surgeons should be aware that 3-level PCO offers an improved safety profile compared to single-level PSO.

The Effect of COVID-19 on Spine Surgery

STUDY DESIGN/SETTING

Retrospective cohort analysis.

OBJECTIVES

To characterize the impact of COVID-19 on utilization of the ten most common spine procedures and percentages of outpatient procedures.

METHODS

The PearlDiver national database was queried from January 2010 to April 2021 for short (<6 segments) and long segment posterior instrumented fusion (≥6 segments), posterior cervical fusion, anterior cervical decompression and fusion (ACDF), cervical laminectomy, laminoplasty, and disc arthroplasty, lumbar laminectomy, microdiscectomy, and interbody fusion. Annual procedure utilization between January 2010 through April 2021 was recorded and compared. Monthly trends were compared to January 2020. Outpatient trends were compared between 2010-2019 and 2019-2021 using segmented linear regression.

RESULTS

Overall, all ten procedures decreased 4.3% in 2020 compared to 2019 and increased 6.3% in 2021 compared to 2019. March and April of 2020 had the largest decreases, with March 2020 decreasing 18.2% and April 2020 decreasing 51.6% compared to January 2020. Despite increasing COVID cases in January 2021, overall procedure utilization decreased only 1.8% compared to January 2020, and increased later in 2021 with April 2021 case volumes increasing by 138% compared to January 2020. Outpatient utilization of short segment posterior lumbar fusion and lumbar interbody fusion significantly increased during this time (P < .001).

CONCLUSION

The greatest impact on spine surgery volume from the COVID-19 pandemic occurred in March and April 2020. Spine procedure utilization was otherwise similar or increased compared to January 2020. Additionally, the volume of outpatient short segment posterior fusion and lumbar interbody fusions increased during this time period.

Are Cervical Disc Arthroplasty Medicare Reimbursement Trends Sustainable?

BACKGROUND

Cervical disc arthroplasty (CDA) was originally approved by the US Food and Drug Administration (FDA) in 2007 as a motion-sparing procedure to treat cervical degenerative disc disease. Since then, promising results from randomized control trials have led to increasing popularity. However, data discussing monetary trends are limited. The aim of this study was to determine how utilization, hospital charges, and Medicare physician reimbursement for CDA have changed over time.

METHODS

In this retrospective cohort study, International Classification of Diseases procedure codes were used to identify all patients who underwent CDA from 2007 to 2017 in the National Inpatient Sample database. The Physician Fee Schedule Look-up Tool from the Centers for Medicare and Medicaid Services was queried for primary CDA using current procedural terminology codes to determine Medicare physician reimbursement from 2009 to 2021. Nominal monetary values were adjusted for inflation using the Consumer Price Index and inflation-adjusted data reported in 2021 US dollars.

RESULTS

A total of 33,079 weighted patients who underwent CDA were included for analysis. CDA utilization increased by 183% from 2007 to 2017, with Medicare beneficiary utilization increasing 149%. Inflation-adjusted total hospital charges for CDA increased by 22.4%. However, inflation-adjusted Medicare physician reimbursement fell by 1.20% per year, demonstrating a total decrease of 12.9%, starting at $1928 in 2009 and declining to $1679 in 2021.

CONCLUSIONS

While utilization and total hospital charges for CDA continue to rise, Medicare physician reimbursement has not shown the same trend. In fact, inflation-adjusted reimbursement has seen a steady decline since FDA approval in 2007. If this trend persists, it may become unsustainable for physicians to continue offering CDA to Medicare patients. As disproportionate increases in hospital charges incentivize a transition to outpatient CDA, stricter patient selection criteria associated with outpatient procedures may create health care disparities for Medicare patients and those with higher comorbidity burden.

CLINICAL RELEVANCE

This study shows the decreasing reimbursement trends for CDA, which may disproportionately affect Medicare patients and those with increased comorbidities.

LEVEL OF EVIDENCE: 3

The Role of Psychosocial Screening in Patient Selection for Spine Surgery: A Review

BACKGROUND

The purpose of this review is to provide a brief history of previous attempts at developing patient screening tools and to further examine the definitions of these psychological concepts, relevance to clinical outcomes, and implications for spine surgeons during preoperative patient assessments.

METHODS

A literature review was performed by 2 independent researchers to identify original manuscripts related to spine surgery and novel psychological concepts. The history of presurgical psychology screening was also studied, and definitions of frequently utilized metrics were detailed.

RESULTS

Seven manuscripts were identified that utilized psychological metrics for preoperative risk assessments and correlated outcomes with these scores. The metrics most frequently used in the literature included resilience, patient activation, grit, and self-efficacy.

DISCUSSION

Current literature favors resilience and patient activation as important metrics for preoperative patient screening. Available studies demonstrate significant associations between these character traits and patient outcomes. Further research is warranted to investigate the roles of preoperative psychological screening to optimize patient selection in spine surgery.

CLINICAL RELEVANCE

The purpose of this review is to provide clinicians with a reference for available psychosocial screening tools and their relevance to patient selection. This review also serves to guide future research directions given the importance of this topic.

LEVEL OF EVIDENCE: 4

Incidence of complications associated with cervical spine surgery and post-operative physical therapy and implications for timing of initiation of post-operative physical therapy: a retrospective database study

PURPOSE

To describe the incidence of complications associated with cervical spine surgery and post-operative physical therapy (PT), and to identify if the timing of initiation of post-operative PT impacts the incidence rates.

METHODS

MOrtho PearlDiver database was queried using billing codes to identify patients who had undergone Anterior Cervical Discectomy and Fusion (ACDF), Posterior Cervical Fusion (PCF), or Cervical Foraminotomy and post-operative PT from 2010-2019. For each surgical procedure, patients were divided into three 12-week increments for post-operative PT (starting at post-operative weeks 2, 8, 12) and then matched based upon age, gender, and Charlson Comorbidity Index score. Each group was queried to determine complication rates and chi-square analysis with adjusted odds ratios, 95% confidence intervals, and p-values were used.

RESULTS

Following matching, 3,609 patients who underwent cervical spine surgery at one or more levels and had post-operative PT (ACDF:1784, PCF:1593, and cervical foraminotomy:232). The most frequent complications were new onset cervicalgia (2-14 weeks, 8-20 weeks, 12-24 weeks): ACDF (15.0%, 14.0%, 13.0%), PCF (18.8%, 18.0%, 19.9%), cervical foraminotomy (16.8%, 16.4%, 19.4%); revision: ADCF (7.9%, 8.2%, 7.4%), PCF (9.3%, 10.6%, 10.2%), cervical foraminotomy (11.6%, 10.8% and 13.4%); wound infection: ACDF (3.3%, 3.4%, 3.1%), PCF (8.3%, 8.0%,7.7%), cervical foraminotomy (5.2%, 6.5%, < 4.7%). None of the comparisons were statistically significant.

CONCLUSION

The most common post-operative complications included new onset cervicalgia, revision and wound infection. Complications rates were not impacted by the timing of initiation of PT whether at 2, 8, or 12 weeks post-operatively.

Secondary Fracture Rate After Vertebral Osteoporotic Compression Fracture Is Decreased by Anti-Osteoporotic Medication but Not Increased by Cement Augmentation

BACKGROUND

Painful vertebral osteoporotic compression fractures (OCFs) are often treated with cement augmentation, although controversies exist as to whether or not this increases the secondary fracture risk. Prevention of secondary fracture includes treatment of underlying osteoporosis. The purposes of this study were to determine (1) whether cement augmentation increases the rate of secondary fracture compared with nonoperative management, (2) whether anti-osteoporotic medications reduce the rate of secondary fracture, and (3) the rate of osteoporosis treatment with medications following vertebral OCF.

METHODS

The PearlDiver database was queried for all patients with a diagnosis of OCF from 2015 to 2019. Patients were excluded if they were <50 years old, had a diagnosis of spinal neoplasm or infection, or underwent lumbar fusion in the perioperative period. Secondary fracture risk was assessed using univariate and multivariate logistic regression analysis, with kyphoplasty, vertebroplasty, anti-osteoporotic medications, age, gender, and Elixhauser Comorbidity Index as variables.

RESULTS

A total of 36,145 patients were diagnosed with an OCF during the study period. Of those, 25,904 (71.7%) underwent nonoperative management and 10,241 (28.3%) underwent cement augmentation, including 1,556 who underwent vertebroplasty and 8,833 who underwent kyphoplasty. Patients who underwent nonoperative management had a secondary fracture rate of 21.8% following the initial OCF, compared with 14.5% in the vertebroplasty cohort and 18.5% in the kyphoplasty cohort, which was not a significant difference on multivariate analysis. In the entire cohort, 2,833 (7.8%) received anti-osteoporotic medications and 33,312 (92.2%) did not. The rate of secondary fracture was 10.1% in patients who received medications and 21.9% in those who did not, which was a significant difference on multivariate analysis (odds ratio = 1.23, p < 0.001).

CONCLUSIONS

Cement augmentation did not alter the rate of secondary fracture, whereas anti-osteoporotic medications significantly decreased the risk of subsequent OCF by 19%. Only 7.8% of patients received a prescription for an anti-osteoporotic medication following the initial OCF.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Timing of Total Hip Arthroplasty Affects Lumbar Spinal Fusion Outcomes

STUDY DESIGN

This is a retrospective cohort study of consecutive patients undergoing lumbar spinal fusion (LSF) within the PearlDiver Humana research database from 2010 to 2018.

OBJECTIVE

The aim of this study was to determine if timing of total hip arthroplasty (THA) affects LSF outcomes.

SUMMARY OF BACKGROUND DATA

In patients with both spine and hip pathology, outcomes of THA have been shown to be affected by the timing of THA relative to LSF. However, few studies have assessed postoperative outcomes following LSF in this clinical scenario.

MATERIALS AND METHODS

A national database was queried for patients undergoing lumbar fusion and divided into 4 groups: (1) those who underwent LSF without THA (No THA); (2) those who underwent THA at least 2 years before LSF (>2 Prior THA); (3) those who underwent THA in the 2 years before LSF (0-2 Prior THA); and (4) those who underwent THA after LSF (THA After). We assessed lumbar-specific outcomes, including pseudarthrosis, revision, mechanical failure, and adjacent segment disease (ASD); as well as systemic complications. Controlling for age, sex, and Charlson comorbidity index, complication rates between all groups were assessed using univariate and multivariate logistic regression analysis. Post hoc comparisons were performed using the Fisher exact test with Bonferroni correction to account for multiple pairwise comparisons, resulting in an adjusted threshold for statistical significance of P<0.007.

RESULTS

When compared with the no THA group, those in the THA After group had a higher rate of ASD on multivariate analysis [adjusted odds ratio: 1.53, 95% confidence interval: 1.20-1.94, P<0.001]. When compared with all patients who underwent THA before LSF, patients who underwent THA after LSF had an increased risk of ASD (adjusted odds ratio: 3.80, 95% confidence interval: 2.21-6.98, P<0.001).

CONCLUSIONS

Patients who undergo THA after LSF have an increased rate of lumbar-related complications both when compared with patients who do not undergo THA and when compared with patients who undergo THA before LSF.

Single position lumbar fusion: a systematic review and meta-analysis

BACKGROUND CONTEXT

Recently, a single position lumbar fusion has been described in which both the anterior or lateral interbody fusion as well as posterior percutaneous pedicle screw fixation are performed in a single position.

PURPOSE

The purpose of this study was to present and analyze the current evidence for single position lumbar fusion.

STUDY DESIGN/SETTING

This is a systematic review and meta-analysis.

PATIENT SAMPLE

Prospective or retrospective studies published in English that assessed outcomes of single position lumbar fusion surgery for patients with lumbar degenerative disease, spondylolisthesis, or radiculopathy were included.

OUTCOME MEASURES

Outcome measures included operative time, estimated blood loss, hospital length of stay, X-Ray exposure time, and postoperative outcomes including leg numbness or pain, leg weakness, lumbar lordosis, and segmental lordosis.

METHODS

This systematic review was performed in accordance with PRISMA guidelines. Two separate meta-analyses were performed. The first compared single position (SP) surgery, both lateral and prone, to dual position or flipped (F) surgery. The second meta-analysis compared lateral single position (LSP) surgery to prone single position (PSP) surgery. Variables were included if (1) they were a mean with a reported standard deviation or (2) if they were a categorical variable. For calculating standard error of the mean, we used sample size, mean, and standard deviation. A random effects model was used. The heterogeneity among studies was assessed with a significance level of <0.05.

RESULTS

Twenty-one articles were included for analysis. Three studies were prospective nonrandomized studies, while 18 were retrospective. Seven articles studied lateral single position only, 10 articles compared lateral single position to traditional repositioning surgery, three articles studied prone single position surgery, and one article compared prone single position surgery to traditional repositioning surgery. A detailed review is provided for all 21 articles. Seventeen studies were included for meta-analysis comparing the SP versus F groups, for a total of 942 patients in the SP group and 254 in the F group. Mean operative time was significantly less for the SP group compared with the F group (SP: 127.5±7.9, F: 188.7±15.5, p<.001). Average hospital length of stay was 2.87±0.3 days in the SP group and 6.63±0.6 days in the F group (p<.001). Complication rates did not significantly differ between groups. Pedicle screws placed in the lateral position had a higher rate of complication as compared with those placed in a prone position (L: 10.2±2%, P: 1.6±1%, p=.015). Seventeen studies were included in the LSP versus PSP analysis, including 13 in the LSP group and four in the PSP group, with a total of 785 patients in the LSP group and 85 patients in the PSP group. Operative time and X-Ray exposure was significantly less in the LSP compared with the PSP group (117.1±5.5 minutes vs. 166.9±21.9 minutes, p<.001; 43.7±15.5 minutes vs. 171.0±25.8 minutes, p<.001). Postoperative segmental lordosis was greater in the prone single position group (p<.001).

CONCLUSIONS

Single position surgery decreases operative times and hospital length of stay, while maintaining similar complication rates and radiographic outcomes. PSP surgery was found to be longer in duration and have increased radiation exposure time compared with LSP, while increasing postoperative segmental lordosis.

Acute Operative Management of Osteoporotic Vertebral Compression Fractures Is Associated with Decreased Morbidity

Study Design

Retrospective national database study design.

Purpose

This study was designed to determine whether acute percutaneous vertebral augmentation (PVA) alters morbidity compared with nonoperative management.

Overview of Literature

Osteoporotic vertebral compression fractures (OCFs) are common and represent a large economic and patient burden. Several recent studies have focused on whether PVA offers benefits compared with nonoperative treatment.

Methods

A retrospective cohort analysis was conducted using the Nationwide Inpatient Sample from 2015 to 2018. Patients with nonelective admissions for OCFs were identified using International Classification of Diseases (10th edition) codes. The exclusion criteria included age of less than 50 years, fusion and decompression procedures, and the presence of neoplasms and infections. Propensity score matching was implemented to construct 2:1 matched cohorts with similar comorbidities at admission. The patients were divided into the operative and nonoperative treatment groups. Univariate and multivariate regression analyses were performed to compare differences in in-hospital complication rates between the groups. All p-values of less than 0.05 were considered significant.

Results

We identified 14,850 patients in the operative group and 29,700 patients in the nonoperative group. In the multivariate analysis, operative treatment was associated with significantly lower rates of pneumonia (odds ratio [OR], 0.75; p<0.001), acute respiratory failure (OR, 0.84; p=0.009), myocardial infarction (OR, 0.20; p<0.001), acute heart failure (OR, 0.80; p=0.001), cardiogenic shock (OR, 0.23; p=0.001), sepsis (OR, 0.39; p<0.001), septic shock (OR 0.50; p<0.001), and pressure ulcerations (OR, 0.71; p<0.001). However, operative treatment was associated with a significantly greater risk of acute renal failure (OR, 1.19; p<0.001) than nonoperative treatment.

Conclusions

Patients who undergo acute PVA for OCFs have lower rates of respiratory complications, cardiac complications, sepsis, and pressure ulcerations while having a higher risk of acute renal failure.

Complication Trends and Costs of Surgical Management in 11,086 Osteoporotic Patients Receiving Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to compare different aspects of fusion surgery in patients with osteoporosis with regard to graft subtype and surgical approach.

SUMMARY OF BACKGROUND DATA

Osteoporosis and chronic lower back pain are common in elderly populations and significantly increase the risk of compression fractures within the spine.

METHODS

Using the 2016-2017 National Readmission Database we identified 11,086 osteoporotic patients who received lumbar fusion using ICD-10 coding. Information regarding biologic graft type and surgical approach was collected. Patients were stratified by number of levels fused. Perioperative complications were collected at 30-, 90-, and 180-day follow-up intervals. Statistical analysis included univariate testing and multivariate regression modeling, controlling for patient demographics and comorbidities.

RESULTS

Patients receiving single-level fusion with autologous grafts had higher rates of hardware failure (P = 0.00014) at 30-day follow-up and 90-day follow-up (P < 0.0001) and higher rates of lumbar vertebral fractures at 90-day follow-up (P = 0.045) compared to those treated with nonautologous grafts. Patients receiving lumbar fusion with anterior and posterior approaches had no difference in readmission or infection rates, but the anterior approach was associated with a higher cost.

CONCLUSION

In this study, osteoporotic patients treated with autologous grafts had higher rates of complications compared to those treated with nonautologous grafts. Anterior and posterior approaches had similar complication rates; however, the anterior approach was associated with a higher total cost.Level of Evidence: 4.

The Impact of Physical Therapy Following Cervical Spine Surgery for Degenerative Spine Disorders: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To characterize the effects of postoperative physical therapy (PT) after surgery for cervical spondylosis on patient-reported outcomes and impairments. Secondarily, to identify associated complications, adverse effects, and health care costs with postoperative PT, and to describe the content, timing, and duration of the PT.

SUMMARY OF BACKGROUND DATA

Cervical spine surgery is common; however, it is unclear if the addition of postoperative PT leads to improved patient outcomes and decreased health care costs.

MATERIALS AND METHODS

PubMed, Embase, Cochrane Central Register of Controlled Trials, Physiotherapy Evidence Database, and Web of Science were searched until July 2019. All peer-reviewed articles involving cervical spine surgery with postoperative PT for cervical spondylosis were considered for inclusion. Risk of bias was assessed using the Revised Cochrane risk-of-bias tool for randomized trials. Findings were described narratively, and GRADE approach was used to define the quality of evidence.

RESULTS

A total of 10,743 studies were screened. Six studies met inclusion criteria; 2 randomized controlled trials and 4 subsequent follow-up studies containing study arms that included postoperative PT after cervical spine surgery. Meta-analysis was not performed due to study heterogeneity and no study compared PT+surgery to surgery alone. PT treatment included exercise therapy, cognitive behavioral therapy, and optional vestibular rehabilitation. Included studies indicated PT appeared to have positive effects on patient outcomes, however, there were no treatment control groups and the quality of evidence was very low to low. Timing, duration, and content of PT programs varied. No studies reported complications, adverse effects, or cost-effectiveness relating to PT after surgery.

CONCLUSIONS

Current literature prevents a definitive conclusion regarding the impact of postoperative PT, given the lack of treatment control groups. PT treatment was limited to exercise therapy, cognitive behavioral therapy, and optional vestibular rehabilitation in the included studies. PT treatment varied, limiting consistent recommendations for content, timing, and treatment duration. Controlled trials are needed to determine the effectiveness of the addition of postoperative PT following cervical spine surgery for cervical spondylosis.

LEVEL OF EVIDENCE

Level II.

Venous Thromboembolism Prophylaxis in Elective Spine Surgery

STUDY DESIGN

Review.

OBJECTIVE

Venothromboembolic (VTE) complications, composed of deep vein thrombosis and pulmonary embolism are commonly observed in the perioperative setting. There are approximately 500 000 postoperative VTE cases annually in the United States and orthopedic procedures contribute significantly to this incidence. Data on the use of VTE prophylaxis in elective spinal surgery is sparse. This review aims to provide an updated consensus within the literature defining the risk factors, diagnosis, and the safety profile of routine use of pharmacological prophylaxis for VTE in elective spine surgery patients.

METHODS

A comprehensive review of the literature and compilation of findings relating to current identified risk factors for VTE, diagnostic methods, and prophylactic intervention and safety in elective spine surgery.

RESULTS

VTE prophylaxis use is still widely contested in elective spine surgery patients. The outlined benefits of mechanical prophylaxis compared with chemical prophylaxis varies among practitioners.

CONCLUSION

The benefits of any form of VTE prophylaxis continues to remain a controversial topic in the elective spine surgery setting. A specific set of guidelines for implementing prophylaxis is yet to be determined. As more risk factors for thromboembolic events are identified, the complexity surrounding intervention selection increases. The benefits of prophylaxis must also continue to be balanced against the increased risk of bleeding events and neurologic injury.

Biomechanical Analysis of an Anterior Cervical Discectomy and Fusion Pseudarthrosis Model Revised With Machined Interfacet Allograft Spacers

STUDY DESIGN

Biomechanics study.

OBJECTIVES

To evaluate the biomechanical advantage of interfacet allograft spacers in an unstable single-level and 2-level anterior cervical discectomy and fusion (ACDF) pseudoarthrosis model.

METHODS

Nine single-level and 8 two-level ACDF constructs were tested. Range of motion in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) at 1.5 N m were collected in 4 testing configurations: (1) intact spine, (2) ACDF with interbody graft and plate/screw, (3) ACDF with interbody graft and plate/loosened screws (loose condition), and (4) ACDF with interbody graft and plate/loosened screws supplemented with interfacet allograft spacers (rescue condition).

RESULTS

All fixation configurations resulted in statistically significant decreases in range of motion in all bending planes compared with the intact spine (P < .05). One Level. Performing ACDF with interbody graft and plate on the intact spine reduced FE, LB, and AR 60.0%, 64.9%, and 72.9%, respectively. Loosening the ACDF screws decreased these reductions to 40.9%, 44.6%, and 52.1%. The addition of interfacet allograft spacers to the loose condition increased these reductions to 74.0%, 84.1%, and 82.1%. Two Level. Performing ACDF with interbody graft and plate on the intact spine reduced FE, LB, and AR 72.0%, 71.1%, and 71.2%, respectively. Loosening the ACDF screws decreased these reductions to 55.4%, 55.3%, and 51.3%. The addition of interfacet allograft spacers to the loose condition significantly increased these reductions to 82.6%, 91.2%, and 89.3% (P < .05).

CONCLUSIONS

Supplementation of a loose ACDF construct (pseudarthrosis model) with interfacet allograft spacers significantly increases stability and has potential applications in treating cervical pseudarthrosis.

Comparison of Proximal Junctional Failure and Functional Outcomes Across Varying Definitions of Proximal Junctional Kyphosis

BACKGROUND

Proximal junctional kyphosis (PJK) is a well-recognized complication following surgery for adult spinal deformity (ASD); however, definitions for PJK and its clinical implications can significantly vary by study. This study compares multiple definitions of PJK and describes incidence and clinical significance by definition.

METHODS

From 2014 to 2019, patients with ASD who underwent spinal fusion were identified. Nine definitions of PJK were created based on previously established definitions using the following upper instrumented vertebra +2 (UIV+2) sagittal Cobb measurements: A= ≥10 postoperative AND preoperative, B = ≥10 postoperative, C = ≥10 preoperative, D = ≥15 postoperative AND preoperative, E = ≥15 postoperative, F = ≥15 preoperative, G = ≥20 postoperative AND preoperative, H = ≥20 postoperative, I = >20 preoperative. Incidence of PJK was calculated by definition. Area under the curve (AUC) was calculated based on a receiver operating characteristic to assess ability to predict proximal junctional failure (PJF). Univariate analysis was performed to assess association with postoperative Oswestry Disability Index (ODI) scores.

RESULTS

Across 82 patients, the incidence of PJK and AUC by definition was as follows: A = 47%, 0.47; B = 72%, 0.65; C = 49%, 0.45; D = 27%, 0.46; E = 57%, 0.62; F = 27%, 0.46; G = 10%, 0.55; H = 40%, 0.71; I = 10%, 0.55. No definition was associated with postoperative ODI scores (P < 0.05).

CONCLUSIONS

The incidence of PJK significantly decreased with stricter definitions. Definitions utilizing only postoperative UIV+2 values had higher incidences but were more likely to capture patients who developed PJF. No definition was associated with postoperative ODI scores. UIV+2 ≥20 was best in distinguishing patients who developed PJF.

Assessment of Lowest Instrumented Vertebra Tilt on Radiographic Measurements in Lenke "C" Modifier Curves Undergoing Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Multicenter, retrospective cohort study.

OBJECTIVES

The purpose of this study is to determine how the amount of residual lowest instrumented vertebra (LIV) tilt correlates with radiographic measurements. When performing a selective thoracic posterior spinal fusion for adolescent idiopathic scoliosis (AIS), the LIV may be tilted into the lumbar curve or made horizontal.

METHODS

This is a multicenter retrospective study of 33 consecutive patients with AIS, Lenke types 1 to 4, lumbar modifier C, and a minimum follow-up of 2 years, who underwent selective thoracic posterior spinal fusions. Measurements obtained from pre- and postoperative radiographs were correlated with postoperative LIV tilt.

RESULTS

At final follow-up, less postoperative LIV tilt significantly correlated with less thoracic apical translation (p =.023) when controlling for the position of the LIV relative to the stable vertebra and preoperative thoracic and lumbar curve flexibility. LIV tilt was not significantly associated with thoracic Cobb angle, lumbar Cobb angle, lumbar apical translation, coronal balance, sagittal balance, or the amount of correction obtained compared to their preoperative measurements (p >.05).

CONCLUSION

Decreased LIV tilt was significantly associated with decreased thoracic apical translation. LIV tilt did not significantly correlate with coronal balance or any other radiographic measurement. We caution that these findings may only be applicable in C modifier curves and when the correct LIV is chosen.

LEVEL OF EVIDENCE

Level III, Therapeutic study.